WO2023184880A1 - 电池容量确定方法和装置、以及存储介质 - Google Patents

电池容量确定方法和装置、以及存储介质 Download PDF

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Publication number
WO2023184880A1
WO2023184880A1 PCT/CN2022/118757 CN2022118757W WO2023184880A1 WO 2023184880 A1 WO2023184880 A1 WO 2023184880A1 CN 2022118757 W CN2022118757 W CN 2022118757W WO 2023184880 A1 WO2023184880 A1 WO 2023184880A1
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Prior art keywords
inflection point
battery
voltage
charging
capacity
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PCT/CN2022/118757
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English (en)
French (fr)
Inventor
李晓倩
冯天宇
邓林旺
洪菁菁
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BYD Co Ltd
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BYD Co Ltd
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Priority to JP2024535665A priority Critical patent/JP7844638B2/ja
Priority to EP22934699.4A priority patent/EP4446759A4/en
Priority to KR1020247021718A priority patent/KR20240121779A/ko
Publication of WO2023184880A1 publication Critical patent/WO2023184880A1/zh
Priority to US18/758,033 priority patent/US20240353499A1/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/10—Measuring sum, difference or ratio
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16528—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values using digital techniques or performing arithmetic operations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
    • G01R19/16576—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing DC or AC voltage with one threshold
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/30—Measuring the maximum or the minimum value of current or voltage reached in a time interval
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/3644—Constructional arrangements
    • G01R31/3648—Constructional arrangements comprising digital calculation means, e.g. for performing an algorithm
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/371—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] with remote indication, e.g. on external chargers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3835—Arrangements for monitoring battery or accumulator variables, e.g. SoC involving only voltage measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/80—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including monitoring or indicating arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/80—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including monitoring or indicating arrangements
    • H02J7/84—Control of state of health [SOH]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/385—Arrangements for measuring battery or accumulator variables
    • G01R31/387—Determining ampere-hour charge capacity or SoC
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to the field of battery technology, and in particular to a battery capacity determination method and device, and a non-transitory computer-readable storage medium.
  • SOH State of Health, battery health status
  • SOHC State of Health Capacity, battery capacity health state
  • the remaining battery capacity is mainly calculated by fully charging and fully discharging the battery to calculate the total amount of electricity in the charging or discharging stage, or charging and discharging within a certain SOC (State of Charge, battery state of charge) interval. According to the charging or discharging amount And the corresponding SOC interval to calculate the total battery capacity.
  • SOC State of Charge, battery state of charge
  • one object of the present invention is to propose a battery capacity determination method that can quickly calculate the battery capacity and improve the accuracy of the battery capacity calculation.
  • the second object of the present invention is to provide a non-transitory computer-readable storage medium.
  • the third object of the present invention is to provide a battery capacity determining device.
  • the present invention proposes a battery capacity determination method.
  • the determination method includes: obtaining the first inflection point voltage of the battery and its corresponding first inflection point electric quantity, the second inflection point voltage and its corresponding third inflection point.
  • Two inflection point power the first inflection point voltage is greater than the second inflection point voltage; control the battery to charge, and record the first charging curve of the battery in real time; determine the target inflection point according to the first charging curve; detect the The power of the battery is obtained until the charging is completed, and the first charging power when the battery is charged to the first inflection point and the second charging power when the battery is completed are obtained; and when the determined target inflection point includes the At the first inflection point, the current capacity of the battery is calculated based on the first inflection point power, the first charged power and the second charged power; wherein, the first inflection point power, the first charged power The charged power, the second charged power and the current battery capacity are respectively defined as Q_HVTP, Qch_HVTP, Qch_End and Qnow.
  • the determined target inflection point also includes the second inflection point
  • obtain the third charging power when the battery is charged to the second inflection point and calculate the charging power according to the second inflection point power and the second inflection point.
  • the first charging power and the third charging power correct the first inflection point power; wherein the second inflection point power and the third charging power are respectively defined as Q_LVTP and Qch_LVTP, Q_HVTP, Qch_HVTP, Q_LVTP and Qch_LVTP satisfies the relationship:
  • Q_HVTP Q_LVTP+Qch_HVTP-Qch_LVTP.
  • the first charging curve is analyzed to determine the target inflection point, and when the battery is detected to be fully charged, that is, the charging is completed, the first charging capacity and the battery are obtained when the battery is charged to the first inflection point.
  • the second charging power when charging is completed.
  • the determined target inflection point includes the first inflection point
  • the current capacity of the battery can be calculated based on the first inflection point power, the first charging power and the second charging power of the battery. That is to say, the calculation method of the embodiment of the present invention can accurately calculate any starting state before the target inflection point.
  • the first inflection point power of the aged battery can also be corrected based on the second inflection point power, the first charging power, and the third charging power when the battery is charged to the second inflection point.
  • Obtaining the accurate value of the first inflection point power of the battery in the current aging state can avoid inaccurate calculation of the battery's current capacity due to changes in the first inflection point power caused by battery aging, which is beneficial to improving the accuracy of battery capacity calculation.
  • the speed and accuracy of battery capacity calculation can be greatly improved.
  • the battery capacity determination method further includes: when the determined target inflection point only includes the first inflection point, if the time from the current time to the last correction of the first inflection point power is greater than a preset time, Then, the first inflection point electric quantity is corrected according to the preset empirical formula of the change of the first inflection point electric quantity with time.
  • determining the target inflection point according to the first charging curve includes: obtaining a voltage difference curve of the first charging curve; obtaining a peak voltage corresponding to a maximum value point of the voltage difference curve; and comparing the The peak voltage is combined with the first inflection point voltage and the second inflection point voltage to determine the target inflection point.
  • comparing the peak voltage with the first inflection point voltage and the second inflection point voltage to determine the target inflection point includes: if the peak voltage is greater than the first inflection point voltage, then The maximum value point is the target inflection point, and the target inflection point is the first inflection point; or, if the peak voltage is less than the second inflection point voltage, the maximum value point is the target inflection point, and the maximum value point is the target inflection point.
  • the target inflection point is the second inflection point.
  • comparing the peak voltage with the first inflection point voltage and the second inflection point voltage to determine the target inflection point further includes: if the peak voltage is neither greater than the first inflection point voltage nor is less than the second inflection point voltage, continue charging the battery and find the target inflection point.
  • the first charging curve is a voltage-capacity characteristic curve established based on the first voltage data and the corresponding first capacity data of the battery during charging.
  • Obtaining the voltage difference curve of the first charging curve includes: performing a smoothing filtering process on the first charging curve, and performing a first-order derivation of the first voltage data with respect to the first capacity data to obtain the The first voltage data is related to the change rate of the first capacity data, and a voltage difference curve of the first charging curve is established based on the change rate and the first capacity data.
  • obtaining the first inflection point voltage of the battery and its corresponding first inflection point power, the second inflection point voltage and its corresponding second inflection point power includes: obtaining the second charging curve of the battery; The second charging curve determines the first inflection point and the second inflection point; obtains the first inflection point voltage corresponding to the first inflection point, the first inflection point electric quantity, and the second inflection point corresponding to the second inflection point. The inflection point voltage and the second inflection point electric quantity.
  • obtaining the second charging curve of the battery includes: determining one or more reference batteries; emptying the reference battery before performing constant current charging; recording the second charging curve during the constant current charging process. Capacity data and corresponding second voltage data; and establishing a voltage-capacity characteristic curve according to the second capacity data and corresponding second voltage data, thereby obtaining the second charging curve.
  • the battery capacity determination method further includes: obtaining an initial capacity of the battery; and calculating a battery capacity state of health (SOHC) of the battery based on the current capacity of the battery and the initial capacity of the battery.
  • SOHC battery capacity state of health
  • recording the first charging curve of the battery in real time includes: collecting and recording at least one of the following parameters of the battery through a battery management system (BMS): voltage, current, temperature, current charging time, and charging the amount of electricity; and obtaining the first charging curve according to the BMS charging algorithm.
  • BMS battery management system
  • the first electric quantity is less than the second electric quantity.
  • the first inflection point voltage and the first inflection point electric quantity are the voltage and inflection point electric quantity corresponding to the high voltage platform inflection point in the second charging curve.
  • the second inflection point voltage and the second inflection point electric quantity are the voltage and inflection point electric quantity corresponding to the low voltage platform inflection point in the second charging curve.
  • the battery capacity determination method further includes: obtaining the current capacity of the battery calculated for the previous n times, and calculating the weighted current capacity of the battery based on the current capacity of the battery calculated for the previous n times. capacity.
  • a battery capacity state of health (SOHC) of the battery is calculated based on the weighted current capacity of the battery and the initial capacity of the battery.
  • obtaining the third electric quantity when the battery is charged to the second inflection point includes: obtaining the third electric quantity when the battery is charged to the second inflection point through a battery management system (BMS).
  • BMS battery management system
  • the battery capacity determination method is executed by a computer program stored on a non-transitory computer-readable storage medium.
  • the present invention proposes a non-transitory computer-readable storage medium on which a computer program is stored.
  • the computer program is executed, the battery capacity determination method as described above is implemented.
  • the speed and accuracy of battery capacity calculation can be greatly improved.
  • the present invention proposes a battery capacity determining device, which includes at least one processor and a memory communicatively connected to the at least one processor.
  • the memory stores instructions that can be processed by the at least one processor, and when the instructions are processed by the at least one processor, the battery capacity determination method as described above is implemented.
  • the processor executes the above battery capacity determination method, which can greatly improve the speed and accuracy of battery capacity calculation.
  • a battery, the capacity of the battery is calculated using the battery capacity determination method as described above.
  • the current capacity is calculated using the above battery capacity determination method, which can greatly improve the speed and accuracy of battery capacity calculation.
  • FIG. 1 is a schematic diagram comparing the first charging curve and the charging voltage difference curve of batteries with different aging degrees according to an embodiment of the present invention.
  • Figure 2 is a flow chart of a battery capacity determination method provided by one embodiment of the present invention.
  • FIG. 3 is a functional block diagram of a battery capacity determining device according to an embodiment of the present invention.
  • the battery capacity determination method proposed in the embodiment of the present invention can greatly improve the speed and accuracy of battery capacity calculation.
  • the general concept of the calculation method of the embodiment of the present invention is to detect the voltage-capacity curve in the charging process of the battery to be tested in real time, analyze the curve characteristics, and find the curve characteristic points. There is no need to deeply discharge the battery before charging and the battery is initially charged. Battery capacity can be accurately calculated even when the SOC status is unknown.
  • the voltage-capacity characteristic curve i.e., charging curve
  • a battery such as but not limited to a lithium-ion battery
  • the point where the voltage changes the fastest in this area is called the voltage platform inflection point. It is distinguished by the voltage level.
  • the higher voltage is called the high voltage platform inflection point (note: is HVTP), and the lower voltage is called the low voltage platform inflection point (recorded as LVTP).
  • the voltage platform inflection point appears as the maximum value point of the curve on the voltage difference curve.
  • the high voltage platform inflection point and the low voltage platform inflection point can be distinguished according to the voltage value.
  • the SOC state at the beginning of charging is uncertain. If charging starts at a lower SOC segment (for example, 5%), two platform inflection points of HVTP and LVTP can be detected during the charging process. ; If charging starts in the middle SOC segment (that is, the area between HVTP and LVTP), only one platform inflection point of HVTP can be detected during the charging process.
  • Figure 1 shows the charging curves and voltage difference curves of various batteries. Different curves represent batteries with different aging levels. It is not difficult to see that the curve of a battery with a lighter aging degree will have two inflection points of high and low voltage platforms.
  • the inflection point power corresponding to LVTP is Q_LVTP (or also known as is the inflection point characteristic capacity of the low-voltage platform) remains basically unchanged, that is, the inflection point power Q_LVTP is a fixed value, and the inflection point power Q_HVTP corresponding to HVTP (or called the high-voltage platform inflection point characteristic capacity) changes slightly within a certain aging range, but HVTP
  • the voltages corresponding to LVTP and LVTP will not change with the translation of the characteristic curve, so the detected platform inflection points can be distinguished by voltage.
  • FIG. 2 is a flow chart of a battery capacity determination method according to one embodiment of the present invention. As shown in FIG. 2 , the battery capacity determination method according to the embodiment of the present invention at least includes steps S1 to S5. The specific process of each step is as follows:
  • Step S1 Obtain the first inflection point voltage and its corresponding first inflection point power, the second inflection point voltage and its corresponding second inflection point power of the battery, where the first inflection point voltage is greater than the second inflection point voltage.
  • the first inflection point voltage and the first inflection point electrical quantity are the voltage and inflection point electrical quantity corresponding to the inflection point of the high voltage platform, and the second inflection point voltage and the second inflection point electrical quantity are also The voltage corresponding to the inflection point of the low-voltage platform and the amount of energy at the inflection point.
  • the first inflection point voltage and the first inflection point capacity are both characteristic parameters of the battery when it leaves the factory, and both correspond to the first inflection point of the battery when it leaves the factory.
  • the second inflection point voltage and the second inflection point capacity are both characteristic parameters of the battery when it leaves the factory, and both correspond to the second inflection point of the battery when it leaves the factory.
  • the first inflection point and the second inflection point are characteristic points of the battery and will change as the battery ages.
  • the first inflection point and the second inflection point correspond to the first inflection point voltage and the second inflection point voltage respectively, or in other words, the first inflection point and the second inflection point correspond to the first inflection point power and the second inflection point power respectively, but as the battery With use, the battery capacity will decrease, and the voltage values corresponding to the first inflection point and the second inflection point may change. In some cases, the voltage value corresponding to the second inflection point will be smaller than the second inflection point voltage, and the voltage value corresponding to the first inflection point is generally not much different from the first inflection point voltage.
  • the voltage corresponding to the high-voltage platform inflection point or the low-voltage platform inflection point in the voltage-capacity characteristic curve and the inflection point power can be determined, and only need to The values of these characteristic quantities can be obtained through the voltage-capacity characteristic curve of a small number of batteries.
  • the specific acquisition method will be described in detail in the subsequent content.
  • Step S2 Control the battery to charge, and record the first charging curve of the battery in real time.
  • the first capacity data of the battery during the charging process and its corresponding first voltage data are recorded in real time.
  • the voltage-capacity characteristic curve established by the first voltage data is the first charging curve.
  • the voltage, voltage, and The current, temperature, current charging time, charging power and other parameters are collected and recorded.
  • the charging curve of the lithium-ion power battery can be obtained according to the BMS charging algorithm, which will not be described in detail.
  • Step S3 Determine the target inflection point according to the first charging curve.
  • the first charging curve is analyzed to obtain its inflection point, and whether the inflection point of the first charging curve is a target inflection point is determined based on the first inflection point voltage and the second inflection point voltage.
  • the high-voltage platform inflection point can be detected during the charging process, which means that the target inflection point at least includes the high-voltage platform inflection point (defined as the first inflection point ), the specific method of determining the target inflection point will be described in detail in subsequent content.
  • Step S4 Detect the power of the battery until charging is completed, and obtain the first charging power when the battery is charged to the first inflection point and the second charging power when the battery is completed. It should be noted that the completion of charging means that the battery reaches a fully charged state.
  • the charging power from the beginning of charging to when the battery reaches the first inflection point is used as the first charge.
  • the charging capacity of the battery from the beginning of charging to the completion of charging of the battery is used as the second charging capacity, and the first charging capacity is smaller than the second charging capacity.
  • the charging capacity of the battery during the charging process can be obtained through the aforementioned BMS, which will not be described in detail here. For example, when the battery starts charging, the power is 10% of the battery capacity. After charging for a certain period of time, the battery is charged to the first inflection point. At this time, the battery power reaches 60% of the battery capacity.
  • the first The charging capacity is 60% when charging to the first inflection point minus 10% when charging starts, that is, the first charging capacity is 50% of the battery capacity.
  • the battery continues to be charged, reaching 100% of battery capacity when the battery charge is complete.
  • the second charging capacity is the charging capacity when the battery is fully charged, in this case, the second charging capacity is 100% minus 10% when charging is started, that is, the second charging capacity is the battery capacity 90%.
  • battery capacity will decrease as the battery usage time increases. In other words, the first charging capacity and the second charging capacity will gradually decrease as the battery ages.
  • Step S5 When the determined target inflection point includes the first inflection point, calculate the current capacity of the battery based on the first inflection point power, the first charging power, and the second charging power.
  • the current capacity of the battery is also the total power of the battery in the current state.
  • the high voltage platform inflection point ie, the first inflection point
  • the first inflection point is relatively easy to trigger. Therefore, in the embodiment of the present invention, when the determined target inflection point includes the first inflection point (ie, the high voltage platform inflection point), according to the first inflection point power, the first charging power and the The second charging power is used to calculate the current capacity of the battery, and the current capacity of the battery is used to determine the status of the battery, which is beneficial to achieving timely updates of the battery status.
  • the first inflection point power, the first charging power, the second charging power and the current capacity of the battery are respectively defined as Q_HVTP, Qch_HVTP, Qch_End and Qnow
  • the battery capacity determination method can be quickly determined according to the aforementioned relational expression. Calculate the current capacity Qnow of the battery.
  • the target inflection point when charging a battery with an unknown SOC state, is determined by analyzing the first charging curve of the battery, and the battery capacity is obtained when the battery is fully charged, that is, when charging is completed.
  • the first charging capacity when charging to the first inflection point i.e. the high voltage platform inflection point
  • the second charging capacity when the battery is fully charged when the determined target inflection point includes the first inflection point
  • the current capacity of the battery can be calculated from the first inflection point power, the first charge power and the second charge power.
  • the calculation method of the embodiment of the present invention can accurately calculate any starting state before the target inflection point. There is no need to deeply discharge the battery before charging, avoiding the loss of the battery itself caused by full charge or full discharge, and improving the battery efficiency. lifespan and charging safety; furthermore, when calculating the current capacity of the battery, only the first charge amount when the battery reaches the first inflection point and the second charge amount when the battery is completed are detected, which is helpful for quickly calculating the battery capacity. , and there is no need to select an SOC interval. Compared with selecting a specific SOC interval for charging or discharging to calculate battery capacity, it can avoid errors caused by inaccurate SOC estimation on battery status calculation, thus improving the accuracy of battery capacity calculation. In summary, according to the battery capacity determination method of the present invention, the speed and accuracy of battery capacity calculation can be greatly improved.
  • obtaining the first inflection point voltage of the battery and its corresponding first inflection point power, the second inflection point voltage and its corresponding second inflection point power in step S1 specifically includes: obtaining The second charging curve of the battery; determining the first inflection point and the second inflection point according to the second charging curve; obtaining the first inflection point voltage corresponding to the first inflection point, the first inflection point electric quantity, and The second inflection point voltage and the second inflection point electric quantity corresponding to the second inflection point.
  • some reference batteries can be extracted from several batteries of the same batch and same specification and then discharged and charged at a constant current, and the second capacity data and the second capacity data during the charging process of the reference battery can be recorded. Its corresponding second voltage data, and establish a voltage-capacity characteristic curve according to the second capacity data and the second voltage data during the charging process of the reference battery, thereby obtaining the second charging curve.
  • the first inflection point voltage corresponding to the first inflection point i.e., the high voltage platform inflection point
  • the second inflection point That is, the second inflection point voltage corresponding to the low voltage platform inflection point
  • the specific analysis process is the same as the process of analyzing the charging curve of the battery in the test stage in the prior art, and will not be described again.
  • the reference battery in the embodiment of the present invention can be the battery to be tested itself, or one or several batteries from the same batch as the battery to be tested can be extracted.
  • the second charging curve, the first inflection point voltage and its corresponding first inflection point electric quantity, and the second inflection point voltage and its corresponding second inflection point electric quantity may be pre-stored in a non-transitory computer.
  • readable storage media such as NVM (non-volatile memory, non-volatile storage unit) included in BMS or other software.
  • determining the target inflection point according to the first charging curve in step S3 specifically includes: obtaining the voltage difference curve of the first charging curve; obtaining the voltage difference curve The peak voltage corresponding to the maximum value point; compare the peak voltage with the first inflection point voltage and the second inflection point voltage to determine the target inflection point.
  • obtaining the voltage difference curve of the first charging curve includes: performing smoothing filtering on the first charging curve, and performing a processing on the first voltage data with respect to the first capacity data.
  • First-order derivation is used to obtain the change rate of the first voltage data with respect to the first capacity data, and a voltage difference curve of the first charging curve is established based on the change rate and the first capacity data, as shown in Figure 1 .
  • comparing the peak voltage with the first inflection point voltage and the second inflection point voltage to determine the target inflection point specifically includes: if the peak voltage is greater than the first inflection point voltage, Inflection point voltage, then the maximum value point is the target inflection point, and the target inflection point is the first inflection point; or, if the peak voltage is less than the second inflection point voltage, then the maximum value point is the target Inflection point, and the target inflection point is the second inflection point.
  • the peak voltage does not satisfy any of the above relationships with the first inflection point voltage threshold or the second inflection point voltage, continue to search for the next peak voltage. Compare the first voltage or the second voltage.
  • the first inflection point can be determined according to its corresponding voltage difference curve and the voltage values of the first inflection point voltage and the second inflection point voltage. ) and the second turning point (LVTP). More specifically, the maximum value point is selected within the interval of the voltage difference curve, and it is judged whether the point is the maximum value point of the voltage difference curve. If it is not the maximum value point, the battery will continue to be charged, and the first point in the charging process will be recorded in real time.
  • First voltage data and first capacity data find the maximum value point of the curve; if it is the maximum value point, obtain the peak voltage corresponding to the maximum value point of the voltage difference curve based on the maximum value point, and compare the peak voltage with the second Compare the first inflection point voltage in the charging curve. If the peak voltage is greater than the first inflection point voltage, it means that the peak voltage is the target inflection point, and the target inflection point power is the first inflection point power; compare the peak voltage with the second inflection point in the second charging curve If the peak voltage is less than the second inflection point voltage, it means that the peak voltage is the target inflection point, and the target inflection point power is the second inflection point power.
  • the peak voltage is neither greater than the first inflection point voltage nor less than the second inflection point threshold, continue charging and find the target inflection point. Therefore, in the embodiment of the present invention, by adding the restriction condition of the voltage value, it can be determined whether the detected target inflection point is the first inflection point or the second inflection point, and misjudgments caused by abnormal data in the middle interval under special circumstances can also be filtered, thereby improving the accuracy of the detection. Accuracy of battery status calculation.
  • the battery capacity determination method in the embodiment of the present invention further includes the step of correcting the first inflection point power Q_HVTP.
  • the battery capacity determination method further includes step S6:
  • the third charging power when the battery is charged to the second inflection point is obtained, and the third charging power is obtained according to the second inflection point power and the first charging power.
  • the electric quantity and the third charged electric quantity correct the first inflection point electric quantity.
  • the third charging capacity is less than the first charging capacity.
  • the third charging capacity when the battery is charged to the second inflection point during the charging process can be obtained through the aforementioned BMS, which will not be discussed here. Repeat.
  • the third charging power is defined as Qch_LVTP, the first inflection point power Q_HVTP, the second inflection point power Q_LVTP, the first charging power Qch_HVTP and the third charging power
  • the first inflection point electric quantity Q_HVTP can be corrected.
  • the second inflection point power Q_LVTP is a fixed value that does not change due to aging, and the third charge of the battery in any aging state
  • the electric quantity Qch_LVTP and the first charged electric quantity Qch_HVTP are determined values obtained in real time during the battery charging process.
  • the first charged electric quantity Qch_HVTP and the third charged electric quantity The power Qch_LVTP is used to correct the first inflection point power Q_HVTP of the battery after aging, and the accurate value of the first inflection point power Q_HVTP of the battery in the current aging state can be obtained, thereby avoiding the first inflection point power Q_HVTP caused by battery aging.
  • the change in Q_HVTP results in inaccurate calculation of the battery's current capacity Qnow, which is beneficial to improving the accuracy of the battery capacity calculation.
  • the first inflection point power Q_HVTP of the battery can be based on the second inflection point power Q_LVTP, the first charge
  • the input power Qch_HVTP and the third charging power Qch_LVTP are corrected in time.
  • the battery capacity determination method further includes: the time for the last correction of the first inflection point power distance is greater than the preset time, and the determined When the target inflection point only includes the first inflection point, the first inflection point electric quantity is corrected according to a preset empirical formula of the change of the first inflection point electric quantity with time.
  • the preset time can be set according to the aging speed of the battery. For example, for a battery with a slow aging speed, the preset time can be 8 months, 10 months or 1 year. For a faster battery, the preset time may be 4 months, 5 months or 6 months. The preset time may be set according to the specific aging speed of the battery, which is not limited.
  • the time from the first inflection point power Q_HVTP to the last correction is defined as ⁇ T
  • the empirical formula for the change of the first inflection point power Q_HVTP over time is defined as f( ⁇ T).
  • the first inflection point electric quantity is defined as Q_HVTP_ ⁇ T.
  • the first inflection point electric quantity Q_HVTP, the empirical formula f( ⁇ T) and the corrected first inflection point electric quantity are defined as Q_HVTP_ ⁇ T, satisfying the relationship:
  • the empirical formula for the change of the first inflection point power Q_HVTP with time is defined as f( ⁇ T).
  • the empirical formula for the change of the first inflection point power Q_HVTP over time is defined as f( ⁇ T), which can be obtained through multiple tests and will not be described again here.
  • the empirical formula of the change of the first inflection point power Q_HVTP over time can be based on the last corrected first inflection point power Q_HVTP and the test obtained It is defined as f( ⁇ T) to correct the first inflection point power Q_HVTP.
  • the battery capacity determination method of the embodiment of the present invention can satisfy different users' different usage habits of battery charging and discharging. It can be understood that, no matter which correction method is based on, the corrected first inflection point power Q_HVTP and the correction time of the first inflection point power Q_HVTP can be stored in a readable storage medium, for example, the aforementioned BMS contains NVM or other software to calculate the battery status next time.
  • the battery capacity determination method further includes: obtaining the initial capacity of the battery; and calculating the SOHC of the battery based on the current capacity of the battery and the initial capacity of the battery.
  • the initial capacity of the battery is defined as Qnew
  • the current capacity of the battery calculated for the previous n times can be obtained, and Calculate the weighted current capacity Qnow of the battery based on the current capacity of the battery calculated n times, and calculate the SOHC of the battery based on the weighted current capacity Qnow of the battery.
  • the weighted current capacity Qnow of the battery can be calculated according to the following formula:
  • Qnow is the weighted current capacity of the battery
  • Qnow 1 to Qnow n are the current capacities of the battery calculated n times
  • n 1 -n n are the weight parameters corresponding to the current capacity of the battery n times
  • n 1 +n 2 +...n n 1
  • the specific value of n 1 -n n can be set based on the historical data and current working conditions of the battery, and is not limited.
  • the SOHC of the battery is calculated according to the aforementioned SOHC calculation formula, and the calculation result is more accurate.
  • the following takes the power battery of an electric vehicle as an example to illustrate the battery capacity determination method in the embodiment of the present invention.
  • the battery capacity determination method is executed, it mainly includes the following steps:
  • the capacity curve (i.e., the aforementioned second charging curve) is obtained by analyzing the characteristics of the charging voltage curve to obtain the first inflection point voltage and the first inflection point quantity Q_HVTP corresponding to the high voltage platform inflection point of the battery (i.e., the first inflection point), and The second inflection point voltage and the second inflection point power Q_LVTP corresponding to the battery's low voltage platform inflection point (ie, the second inflection point), where the first inflection point Q_HVTP will be stored in the NVM of the BMS, and the second inflection point
  • the electric quantity Q_LVTP is a fixed value written into the corresponding software of the BMS, so that it can be quickly called to implement subsequent calculations.
  • the second step is to start charging the battery to be tested with unknown SOC status in real vehicle applications, and record the voltage-capacity curve of the battery after the start of charging in real time (i.e., the aforementioned first charging curve).
  • the first inflection point voltage and the second inflection point voltage obtained in one step determine the target inflection point of the battery; wherein, during the charging process of the battery, the charge of the battery when charging to each node is obtained in real time.
  • the charging capacity includes the first charging capacity Qch_HVTP when the battery is charged to the first inflection point, the second charging capacity Qch_End when the battery is charged, and the third charging capacity when the battery is charged to the second inflection point. 3. Charge into Qch_LVTP.
  • the first inflection point power Q_HVTP is corrected and updated according to the determined target inflection point and the charging power corresponding to the target inflection point.
  • the specific correction method is: 1. If it is detected at the same time The first inflection point (HVTP) and the second inflection point (LVTP) are corrected according to the second inflection point power Q_LVTP, the first charging power Qch_HVTP and the third charging power Qch_LVTP. Inflection point power Q_HVTP, and its update time is stored in NVM for subsequent calculations; 2.
  • the first inflection point electric quantity Q_HVTP is corrected according to the empirical formula f ( ⁇ T) and its update time is stored in NVM for subsequent calculations; for more detailed information on the above two correction methods, please refer to the above-mentioned relevant content, here No longer.
  • the fourth step is to calculate the current capacity Qnow of the battery after the battery is charged to a fully charged state. After the current capacity Qnow of the battery is calculated, the SOHC of the battery is further calculated based on the current capacity of the battery. . It should be noted that the detailed calculation method of the current capacity Qnow of the battery and the SOHC of the battery can be found in the above-mentioned relevant contents, and will not be described again here.
  • the batteries used in electric vehicles can at least detect the high-voltage platform inflection point (first inflection point) located in a higher SOC segment. ), making the battery capacity determination method of the embodiment of the present invention particularly suitable for power batteries of electric vehicles.
  • the battery status when calculating the battery status according to the battery capacity determination method of the embodiment of the present invention, there is no need to deeply discharge the battery before charging, which avoids the loss of the battery itself caused by full charge or full discharge, which is beneficial to improving the life of the battery. and charging safety; Furthermore, when calculating the current capacity of the battery, it is only necessary to detect the first charging capacity when the battery is charged to the first inflection point (i.e., the high voltage platform inflection point) and the second charging capacity when the battery charging is completed, that is The battery's capacity can be quickly calculated based on the battery's first inflection point capacity (i.e., the characteristic capacity of the high-voltage platform's inflection point), and there is no need to select a SOC interval.
  • the first inflection point i.e., the high voltage platform inflection point
  • the second charging capacity when the battery charging is completed
  • the determined target inflection point includes the first inflection point and the second inflection point (i.e., the low-voltage platform inflection point), the second inflection point power (i.e., the low-voltage platform inflection point characteristic capacity), the first charging power, and the battery charge to
  • the third charging power at the second inflection point corrects the power at the first inflection point.
  • the power at the first inflection point can be corrected according to the preset first inflection point.
  • the empirical formula of the change of the inflection point power with time is used to correct the first inflection point power. In this way, by correcting the first inflection point power in time, it can avoid inaccurate calculation of the battery's current capacity due to changes in the first inflection point power due to battery aging, which is beneficial to improve
  • the accuracy of the battery status calculation and the two correction methods for the first inflection point power can enable the battery capacity determination method of the embodiment of the present invention to meet the different usage habits of different users for battery charging and discharging.
  • the non-transitory computer-readable storage medium according to the second embodiment of the present invention has a computer program stored thereon.
  • the computer program When the computer program is executed, the battery capacity determination method mentioned in any of the above embodiments is implemented.
  • the speed and accuracy of battery capacity calculation can be greatly improved.
  • FIG 3 is a functional block diagram of the battery capacity determination device 1 according to the third embodiment of the present invention.
  • the battery capacity determination device 1 provided by the present invention includes at least one processor 10 and the at least one processor.
  • the memory 20 is communicatively connected to the processor 10, wherein the memory 20 stores instructions that can be processed by the at least one processor 10.
  • the instructions are processed by the at least one processor 10, any of the above embodiments can be implemented. How to determine the battery capacity.
  • the battery capacity determination device 1 through its processor 10 executing the battery capacity determination method mentioned in any of the above embodiments, the speed and accuracy of battery capacity calculation can be greatly improved.
  • a battery is provided, and the capacity of the battery can be calculated using the battery capacity determination method mentioned in any of the above embodiments.
  • the current capacity of the battery is calculated through the above-mentioned battery capacity determination method, which can greatly improve the speed and accuracy of battery capacity calculation.

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Abstract

一种电池容量确定方法和装置、以及非临时性计算机可读存储介质。该电池容量确定方法包括：获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量（S1）；控制电池进行充电，并实时记录电池的第一充电曲线（S2）；根据第一充电曲线确定目标拐点（S3）；检测电池的电量直至充电完成，获取第一充入电量和第二充入电量（S4）；在确定的目标拐点包括第一拐点时，根据第一拐点电量、第一充入电量以及第二充入电量计算电池的当前容量（S5）。

Description

电池容量确定方法和装置、以及存储介质
本申请要求于2022年03月29日提交中国专利局、申请号为202210318139.5、申请名称为“电池容量确定方法和装置、存储介质、以及电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及电池技术领域，尤其涉及一种电池容量确定方法和装置，以及一种非临时性计算机可读存储介质。
背景技术
随着电池技术的快速发展，锂离子电池在电动车辆、储能电站等领域有着非常广泛的应用。锂离子电池在不断充放电循环使用中会逐渐老化，性能会逐渐衰减，具体表现为容量减少、内阻增大、以及功率降低等。电池的老化程度表示为SOH(State of Health，电池健康状态)。SOH可通过剩余容量、内阻、循环次数等多种方式来定义，其中，最常用且最直观的方式是通过电池剩余容量进行定义，即电池老化后的容量与电池初始容量的百分比，也称之为SOHC(State of Health Capacity，电池容量健康状态)。
目前，电池剩余容量主要是通过对电池进行满充、满放来计算充电或者放电阶段的总电量，或者在一定SOC(State of Charge，电池荷电状态)区间进行充放电，根据充电或者放电电量以及相应的SOC区间来计算总的电池容量。
然而，以上计算电池剩余容量的方法均存在缺点。具体而言，电池满充、满放不仅花费更多的时间和设备资源，还可能引发过充失火甚至爆炸等一系列安全相关问题，再者，因为用户通常会在电池完全放空前对电池进行充电，使得电池满放工况难以触发，且一旦触发还会影响电池自身寿命，因此通过电池满充满放计算电池剩余容量在应用中并不现实；而在特定SOC区间进行充电或放电以获取电池剩余容量，SOC区间的选取需足够长，同样存在难以触发的问题，而且对SOC估算的精度要求较高，SOC估算不准容易对结果造成较大误差。
发明内容
为解决上述技术问题，本发明的一个目的在于提出一种电池容量确定方法，该方法可以快速计算电池容量并提高电池容量计算的准确性。
本发明的第二个目的在于提出一种非临时性计算机可读存储介质。
本发明的第三个目的在于提出一种电池容量确定装置。
为了实现上述目的，第一方面，本发明提出一种电池容量确定方法，所述确定方法包括：获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量，所述第一拐点电压大于所述第二拐点电压；控制所述电池进行充电，并实时记录所述电池的第一充电曲线；根据所述第一充电曲线确定目标拐点；检测所述电池的电量直至充电完成，获取所述电池充电至所述第一拐点时的第一充入电量和所述电池充电完成时的第二充入电量；以及在确定的所述目标拐点包括所述第一拐点时，根据所述第一拐点电量、所述第一充入电量以及所述第二充入电量计算所述电池的当前容量；其中，所述第一拐点电量、所述第一充入电量、所述第二充入电量和所述电池当前容量分别定义为Q_HVTP、Qch_HVTP、Qch_End和Qnow，Q_HVTP、Qch_HVTP、Qch_End以及Qnow满足关系式：Qnow＝Q_HVTP+ Qch_End-Qch_HVTP。
可选地，在确定的所述目标拐点还包括所述第二拐点时，获取所述电池充电至所述第二拐点时的第三充入电量，并根据所述第二拐点电量、所述第一充入电量及所述第三充入电量校正所述第一拐点电量；其中，所述第二拐点电量和所述第三充入电量分别定义为Q_LVTP和Qch_LVTP，Q_HVTP、Qch_HVTP、Q_LVTP以及Qch_LVTP满足关系式：
Q_HVTP＝Q_LVTP+Qch_HVTP-Qch_LVTP。
根据本发明实施例的电池容量确定方法，通过分析第一充电曲线以确定目标拐点，并在检测到电池的电量充满即充电完成时获得电池充电至第一拐点时的第一充入电量及电池充电完成时的第二充入电量，当确定的目标拐点包括第一拐点时，根据电池的第一拐点电量、第一充入电量和第二充入电量即可计算获得电池的当前容量。也即是说，本发明实施例的计算方法在目标拐点之前的任意起始状态均可精确计算，无需在充电前对电池进行深度放电，避免满充或满放对电池自身造成损耗，提高电池寿命和充电安全；再者，计算电池的当前容量时，只需检测电池充电至第一拐点时的第一充入电量及电池充电完成时的第二充入电量，有利于快速计算电池容量，而且无需进行SOC的区间选取，相较于选取特定SOC区间进行充电或放电计算电池容量，能够避免SOC估算不准对电池状态计算造成的误差，从而提高了电池容量计算的准确性。此外，在计算电池的当前容量时，还可以根据第二拐点电量、第一充入电量及电池充电至第二拐点时的第三充入电量来校正老化后的电池的第一拐点电量，可以获得当前老化状态下的电池的第一拐点电量的准确值，从而可避免因电池老化引起第一拐点电量发生变化而导致电池的当前容量计算不准确，有利于提高电池容量计算的准确性。综上，根据本发明的电池容量确定方法，能够大大提高电池容量计算的速度和准确性。
可选地，所述电池容量确定方法还包括：在确定的所述目标拐点只包括所述第一拐点时，如果当前时间距离所述第一拐点电量的上一次校正的时间大于预设时间，则根据预设的所述第一拐点电量随时间变化的经验公式校正所述第一拐点电量。
可选地，所述根据所述第一充电曲线确定目标拐点包括：获取所述第一充电曲线的电压差分曲线；获取所述电压差分曲线的极大值点对应的峰值电压；以及比较所述峰值电压与所述第一拐点电压和所述第二拐点电压，以确定所述目标拐点。
可选地，所述对比所述峰值电压与所述第一拐点电压和所述第二拐点电压的大小，以确定所述目标拐点包括：若所述峰值电压大于所述第一拐点电压，则所述极大值点为目标拐点，且所述目标拐点为所述第一拐点；或者，若所述峰值电压小于所述第二拐点电压，则所述极大值点为目标拐点，且所述目标拐点为第二拐点。
可选地，所述比较所述峰值电压与所述第一拐点电压和所述第二拐点电压的大小，以确定所述目标拐点，还包括：若峰值电压既不大于第一拐点电压也不小于第二拐点电压，则继续对所述电池充电并寻找目标拐点。
可选地，所述第一充电曲线为根据所述电池在充电过程中的第一电压数据及其对应的第一容量数据建立的电压-容量特性曲线。所述获取所述第一充电曲线的电压差分曲线包括：对所述第一充电曲线进行平滑滤波处理，并对所述第一电压数据关于所述第一容量数据进行一阶求导，获得所述第一电压数据关于所述第一容量数据的变化率，根据所述变化率与所述第一容量数据建立所述第一充电曲线的电压差分曲线。
可选地，所述获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量包括：获取所述电池的第二充电曲线；根据所述第二充电曲线确定所述第一拐点和所述第二拐点；获取所述第一拐点对应的所述第一拐点电压、所述第一拐点电量， 以及所述第二拐点对应的所述第二拐点电压、所述第二拐点电量。
可选地，所述获取所述电池的第二充电曲线，包括：确定一个或多个参考电池；将所述参考电池放空后再进行恒流充电；记录所述恒流充电过程中的第二容量数据及对应的第二电压数据；以及根据所述第二容量数据以及对应的所述第二电压数据建立电压-容量特性曲线，从而获得所述第二充电曲线。
可选地，所述电池容量确定方法还包括：获取所述电池的初始容量；以及根据所述电池的当前容量和所述电池的初始容量计算所述电池的电池容量健康状态(SOHC)。
可选地，所述实时记录所述电池的第一充电曲线，包括：通过电池管理系统(BMS)采集和记录所述电池以下参数中的至少一个：电压、电流、温度、当前次充电时间、和充入电量；以及根据BMS充电算法获取所述第一充电曲线。
可选地，所述第一电量小于所述第二电量。
可选地，所述第一拐点电压和所述第一拐点电量为所述第二充电曲线中的高电压平台拐点对应的电压及拐点电量。
可选地，所述第二拐点电压和所述第二拐点电量为所述第二充电曲线中的低电压平台拐点对应的电压及拐点电量。
可选地，所述电池容量确定方法还包括：获取前n次计算的所述电池的当前容量，并根据所述前n次计算的所述电池的当前容量计算加权后的所述电池的当前容量。
可选地，根据所述加权后的所述电池的当前容量和所述电池的初始容量计算所述电池的电池容量健康状态(SOHC)。
可选地，所述获取所述电池充电至所述第二拐点时的第三电量包括：通过电池管理系统(BMS)获取所述电池充电至所述第二拐点时的第三电量。
可选地，所述电池容量确定方法由存储在非临时性计算机可读存储介质上的计算机程序执行。
第二方面，本发明提出一种非临时性计算机可读存储介质，其上存储有计算机程序，所述计算机程序被执行时实现如上所述的电池容量确定方法。
根据本发明实施例的非临时性计算机可读存储介质，通过执行其存储的计算机程序，能够大大提高电池容量计算的速度和准确性。
第三方面，本发明提出一种电池容量确定装置，所述电池容量确定装置包括至少一个处理器，以及与所述至少一个处理器通信连接的存储器。其中，所述存储器上存储有可被所述至少一个处理器处理的指令，所述指令被所述至少一个处理器处理时实现如上所述的电池容量确定方法。
根据本发明实施例的电池容量确定装置，通过处理器执行上述电池容量确定方法，能够大大提高电池容量计算的速度和准确性。
一种电池，所述电池的容量采用如上所述的电池容量确定方法进行计算。
根据本发明实施例的电池，其当前容量采用上述电池容量确定方法进行计算，能够大大提高电池容量计算的速度和准确性。
本发明的附加方面和优点将在下面的描述内容中部分给出，部分将从下面的描述中变得明显，或通过本发明的实践了解到。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对实施方式中所需要使用的附图作 简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本发明其中一实施例提供的不同老化程度的电池的第一充电曲线以及充电电压差分曲线的对比示意图。
图2是本发明其中一实施例提供的电池容量确定方法的流程图。
图3是本发明其中一实施例提供的电池容量确定装置的功能框图。
具体实施方式
为了使得本申请的目的、技术方案和优点更为明显，下面将参照附图详细描述根据本申请的示例实施例。显然，所描述的实施例仅仅是本申请的一部分实施例，而不是本申请的全部实施例，应理解，本申请不受这里描述的示例实施例的限制。基于本申请中描述的本申请实施例，本领域技术人员在没有付出创造性劳动的情况下所得到的所有其它实施例都应落入本申请的保护范围之内。
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或者具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，仅用于解释本发明，而不能理解为对本发明的限制。
对于现有技术存在的问题，本发明实施例提出的电池容量确定方法，能够大大提高电池容量计算的速度和准确性。本发明实施例的计算方法总的构思为，通过实时检测待测电池充电过程中的电压-容量曲线，分析曲线特性，寻找曲线特征点，在充电前不需要对电池进行深度放电且在电池初始SOC状态未知的情况下也可精确计算电池容量。
首先，对本发明实施例中用到的曲线特征点作解释和说明。
请参阅图1，一般来说，电池(例如是但不限于锂离子电池)的电压-容量特性曲线(即充电曲线)存在三个电压变化较缓慢的区间，称之为电压平台区。两两电压平台区之间存在一段电压变化较快的区域，该区域内电压变化最快的点称之为电压平台拐点，以电压高低来区分，电压较高的称为高电压平台拐点(记为HVTP)，电压较低的称为低电压平台拐点(记为LVTP)。电压平台拐点在电压差分曲线上表现为曲线的极大值点，在实际应用中可以根据电压值的高低对高电压平台拐点与低电压平台拐点进行区分。以电动汽车的动力锂离子电池为例，其充电开始的SOC状态并不确定，如果充电开始于较低的SOC段(例如5％)，充电过程中则可以检测到HVTP、LVTP两个平台拐点；如果充电开始于中间SOC段(即介于HVTP与LVTP之间的区域)，充电过程中仅能检测到HVTP一个平台拐点。图1所示为多种电池的充电曲线以及电压差分曲线图，不同曲线代表不同老化程度的电池，不难看出，老化程度较轻的电池的曲线会具有高、低两个电压平台拐点。
本领域普通技术人员悉知的是，如图1所示，随着电池的老化，电池的电压-容量特性曲线会整体向低容量方向移动，移动过程中LVTP对应的拐点电量Q_LVTP(或者称之为低电压平台拐点特征容量)基本保持不变，即拐点电量Q_LVTP为固定值，HVTP对应的拐点电量Q_HVTP(或者称之为高电压平台拐点特征容量)在一定老化范围内变化较小，但HVTP和LVTP各自对应的电压不会随特性曲线平移而发生变化，故可以用电压对检测到的平台拐点加以区分。
基于上文的解释说明，下面参照附图描述根据本发明实施例的电池容量确定方法。
图2是根据本发明其中一实施例提供的电池容量确定方法的流程图，如图2所示，本发明实施例的电池容量确定方法至少包括步骤S1-步骤S5。每个步骤的具体过程如下：
步骤S1，获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量，所述第一拐点电压大于所述第二拐点电压。本领域普通技术人员可以理解的是，所述第一拐点电压和所述第一拐点电量即高电压平台拐点对应的电压及拐点电量，所述第二拐点电压和所述第二拐点电量也即低电压平台拐点对应的电压及拐点电量。第一拐点电压和第一拐点电量都是电池出厂时的特征参数，并且都与电池出厂时的第一拐点对应。类似地，第二拐点电压和第二拐点电量都是电池出厂时的特征参数，并且都与电池出厂时的第二拐点对应。第一拐点和第二拐点是电池的一个特征点，会随着电池老化改变。出厂时，第一拐点、第二拐点分别和第一拐点电压、第二拐点电压对应，或者说，第一拐点、第二拐点分别和第一拐点电量、第二拐点电量对应，但是随着电池的使用，电池容量会减小，第一拐点和第二拐点对应的电压值可能会改变。在一些情况下，第二拐点对应的电压值会小于第二拐点电压，第一拐点对应的电压值一般和第一拐点电压相差不大。
在本发明的实施例中，对于确定批次及规格的电池而言，其电压-容量特性曲线中的高电压平台拐点或低电压平台拐点对应的电压以及拐点电量都是可以确定的，只需要通过少量电池的电压-容量特性曲线便可获取这些特征量的取值，具体的获取方法在后续内容中会进行详细描述。
步骤S2，控制所述电池进行充电，并实时记录所述电池的第一充电曲线。
在本发明的实施例中，对未知SOC状态的电池进行充电时，实时记录所述电池在充电过程中的第一容量数据及其对应的第一电压数据，根据所述第一容量数据和所述第一电压数据建立的电压-容量特性曲线即所述第一充电曲线。具体地，以锂离子动力电池为例，在现有技术中，对所述锂离子动力电池进行充电时，通过BMS(Battery Management System，电池管理系统)可对所述锂离子动力电池的电压、电流、温度以及当前次充电时间、充入电量等参数进行采集和记录，根据BMS充电算法即可获取所述锂离子动力电池的充电曲线，对此不作赘述。
步骤S3，根据所述第一充电曲线确定目标拐点。
在本发明的实施例中，分析所述第一充电曲线以获取其拐点，并根据所述第一拐点电压和所述第二拐点电压确定所述第一充电曲线的拐点是否为目标拐点。其中，如前所述，对于未知SOC状态的电池来说，在其充电过程中至少可以检测到高电压平台拐点，也即意味着所述目标拐点至少包括高电压平台拐点(定义为第一拐点)，所述目标拐点的具体确定方法在后续内容中会进行详细描述。
步骤S4，检测所述电池的电量直至充电完成，获取所述电池充电至所述第一拐点时的第一充入电量和所述电池充电完成时的第二充入电量。需要说明的是，充电完成是指所述电池达到满充状态。
在本发明的实施例中，检测到所述电池的电量达到满充电量时，将所述电池从开始充电至所述电池充电至所述第一拐点时的充入电量作为所述第一充入电量，将所述电池从开始充电至所述电池充电完成时的充入电量作为所述第二充入电量，所述第一充入电量小于所述第二充入电量。其中，所述电池在充电过程中的充入电量可以通过前述的BMS获得，在此不做赘述。例如，电池在开始充电时电量为电池容量的10％，在充电一定时间后，该电池充电至第一拐点，此时该电池的电量达到电池容量的60％，在这种情况下，第一充入电量为充电至第一拐点时的60％减去开始充电时的10％，即第一充入电量为电池容量的50％。类似地，对电池继续充电，在该电池充电完成时达到电池容量的100％。由于第二充入电量为电池充电完成时的充入电量，因此，在这种情况下，第二充入电量为100％减去开始充电时的10％，即第二 充入电量为电池容量的90％。但是值得注意的是，由于电池老化等因素，电池容量会随着电池使用时间增加而衰减。也就是说，第一充入电量和第二充入电量会随着电池的老化逐渐减小。
步骤S5，在确定的所述目标拐点包括所述第一拐点时，根据所述第一拐点电量、所述第一充入电量以及所述第二充入电量计算所述电池的当前容量。其中，所述电池的当前容量也即所述电池在当前状态下的总电量。
可以理解的是，对于未知SOC状态的电池来说，在其充电过程中至少可以检测到高电压平台拐点(即所述第一拐点)，也即意味着所述第一拐点比较容易触发。因此，在本发明的实施例中，当确定的所述目标拐点包括所述第一拐点(即高电压平台拐点)时，根据所述第一拐点电量、所述第一充入电量以及所述第二充入电量来计算所述电池的当前容量，并通过所述电池的当前容量来判断所述电池的状态，有利于实现所述电池状态的及时更新。
具体地，在本发明的实施例中，将所述第一拐点电量、所述第一充入电量、所述第二充入电量及所述电池的当前容量分别定义为Q_HVTP、Qch_HVTP、Qch_End及Qnow，所述第一拐点电量Q_HVTP、所述第一充入电量Qch_HVTP、所述第二充入电量Qch_End以及所述电池当前容量Qnow满足关系式：Qnow＝Q_HVTP+Qch_End-Qch_HVTP。换句话说，本发明实施例的电池容量确定方法中，只要确定所述第一拐点电量Q_HVTP、所述第一充入电量Qch_HVTP以及所述第二充入电量Qch_End，就可以根据前述关系式快速计算所述电池的当前容量Qnow。
综上，根据本发明实施例的电池容量确定方法，未知SOC状态的电池进行充电时，通过分析电池的第一充电曲线以确定目标拐点，并在检测到电池的电量充满即充电完成时获得电池充电至第一拐点(即高电压平台拐点)时的第一充入电量及电池充电完成时的第二充入电量，当确定的目标拐点包括第一拐点时，根据已经获得的该电池的第一拐点电量、第一充入电量和第二充入电量即可计算获得电池的当前容量。也即是说，本发明实施例的计算方法在目标拐点之前的任意起始状态均可精确计算，无需在充电前对电池进行深度放电，避免满充或满放对电池自身造成损耗，提高电池寿命和充电安全；再者，计算电池的当前容量时，只需检测电池充电至第一拐点时的第一充入电量及电池充电完成时的第二充入电量，有利于快速计算电池的容量，而且无需进行SOC的区间选取，相较于选取特定SOC区间进行充电或放电计算电池容量，能够避免SOC估算不准对电池状态计算造成的误差，从而提高了电池容量计算的准确性。综上，根据本发明的电池容量确定方法，能够大大提高电池容量计算的速度和准确性。
需要说明的是，在本发明的实施例中，步骤S1所述获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量，具体包括：获取所述电池的第二充电曲线；根据所述第二充电曲线确定所述第一拐点和第二拐点；获取所述第一拐点对应的所述第一拐点电压、所述第一拐点电量，以及所述第二拐点对应的所述第二拐点电压、所述第二拐点电量。
具体地，在所述电池的测试阶段，可以从同一批次、相同规格的若干所述电池中抽取部分参考电池放空后进行恒流充电，记录所述参考电池充电过程中的第二容量数据及其对应的第二电压数据，并根据所述参考电池充电过程中的所述第二容量数据和所述第二电压数据建立电压-容量特性曲线，从而获得所述第二充电曲线。进一步地，通过分析所述第二充电曲线的曲线特性，即可确定所述第一拐点(即高电压平台拐点)对应的第一拐点电压及其对应的第一拐点电量，以及第二拐点(即低电压平台拐点)对应的第二拐点电压及其对应的第二拐 点电量，具体的分析过程与现有技中对测试阶段的电池的充电曲线进行分析的过程相同，对此不做赘述。
其中，可以理解的是，由于对于确定批次的电池，其高、低电压平台拐点对应的拐点电量Q_HVTP、Q_LVTP以及对应的电压都是确定的，只需少量的电池特征曲线便可确定这些特征量的取值，所以，本发明实施例中的参考电池可以为待测电池本身，或者可以抽取与待测电池同批次的一个或者几个电池。此外，所述第二充电曲线、所述第一拐点电压及其对应的所述第一拐点电量、以及所述第二拐点电压及其对应的所述第二拐点电量可以预存在非临时性计算机可读存储介质中，例如BMS包含的NVM(non-volatile memory，非易失性存储单元)或者其他软件中。
还需要说明的是，在本发明的实施例中，步骤S3所述根据所述第一充电曲线确定目标拐点，具体包括：获取所述第一充电曲线的电压差分曲线；获取所述电压差分曲线的极大值点对应的峰值电压；对比所述峰值电压与所述第一拐点电压和所述第二拐点电压的大小，以确定所述目标拐点。
在一些实施例中，所述获取所述第一充电曲线的电压差分曲线包括：对所述第一充电曲线进行平滑滤波处理，并对所述第一电压数据关于所述第一容量数据进行一阶求导，获得所述第一电压数据关于所述第一容量数据的变化率，根据该变化率与所述第一容量数据建立所述第一充电曲线的电压差分曲线，见图1所示。
在一些实施例中，所述对比所述峰值电压与所述第一拐点电压和所述第二拐点电压的大小，以确定所述目标拐点，具体包括：若所述峰值电压大于所述第一拐点电压，则所述极大值点为目标拐点，且所述目标拐点为所述第一拐点；或者，若所述峰值电压小于所述第二拐点电压，则所述极大值点为目标拐点，且所述目标拐点为第二拐点。本领域技术人员可以理解的是，在本发明的实施例中，若峰值电压与所述第一拐点电压阈值或所述第二拐点电压不满足以上任一种关系，则继续寻找下一个峰值电压对比所述第一电压或所述第二电压。
具体地，请结合图1，对于任一老化程度的电池而言，根据其对应的电压差分曲线，并结合第一拐点电压和第二拐点电压的电压值大小，即可确定第一拐点(HVTP)以及第二拐点(LVTP)。更具体地，在电压差分曲线的区间内选取最大值点，判断该点是否为电压差分曲线的极大值点，若不是极大值点，则继续为电池充电，通过实时记录充电过程中第一电压数据和第一容量数据，寻找该曲线的极大值点；若是极大值点，则根据该极大值点获取电压差分曲线极大值点对应的峰值电压，将峰值电压与第二充电曲线中的第一拐点电压作比较，若峰值电压大于第一拐点电压，说明该峰值电压为目标拐点，且目标拐点电量为第一拐点电量；将峰值电压与第二充电曲线中第二拐点电压作比较，若峰值电压小于第二拐点电压，说明该峰值电压为目标拐点，且目标拐点电量为第二拐点电量。若峰值电压既不大于第一拐点电压也不小于第二拐点阈值，则继续充电并寻找目标拐点。因此，在本发明实施例中，通过增加电压值的限制条件，可以确定检测到的目标拐点是第一拐点或者第二拐点，以及也可以过滤特殊情况中间区间数据异常造成的误判，提高了电池状态计算的准确性。
如前所述，随着电池的老化，电池的电压-容量特性曲线会整体向低容量方向移动，移动过程中第一拐点(HVTP)对应的第一拐点电量Q_HVTP会在一定老化范围内变化，而第二拐点(LVTP)对应的第二拐点电量Q_LVTP基本保持不变。所述第一拐点电量Q_HVTP会因为电池的老化而发生变化，如此，基于所述第一拐点电量Q_HVTP而计算得到的所述电池的当前容量Qnow的准确性会受到影响。为了提高所述电池容量计算的准确度，本发明实施例的电池容量确定方法还包括对所述第一拐点电量Q_HVTP进行校正的步骤。
具体地，如图2所示，在一些实施例中，所述电池容量确定方法还包括步骤S6：
在确定的所述目标拐点还包括所述第二拐点时，获取所述电池充电至所述第二拐点时的第三充入电量，并根据所述第二拐点电量、所述第一充入电量及所述第三充入电量校正所述第一拐点电量。
其中，所述第三充入电量小于所述第一充入电量，所述电池在充电过程中充电至所述第二拐点时的第三充入电量可以通过前述的BMS获得，在此不再赘述。
在本发明的实施例中，所述第三充入电量定义为Qch_LVTP，所述第一拐点电量Q_HVTP、所述第二拐点电量Q_LVTP、所述第一充入电量Qch_HVTP以及所述第三充入电量Qch_LVTP将满足关系式：Q_HVTP＝Q_LVTP+Qch_HVTP-Qch_LVTP。换句话说，在确定所述第二拐点电量Q_LVTP并获得所述第三充入电量定义为Qch_LVTP和所述第一充入电量Qch_HVTP之后，即可对所述第一拐点电量Q_HVTP进行校正。
可以理解的是，对于确定批次及规格的电池而言，所述第二拐点电量Q_LVTP为不因老化而发生变化的固定值，且所述电池在任一老化状态下的所述第三充入电量Qch_LVTP和所述第一充入电量Qch_HVTP为所述电池充电过程中实时获取的确定值，因此，根据所述第二拐点电量Q_LVTP、所述第一充入电量Qch_HVTP及所述第三充入电量Qch_LVTP来校正老化后的所述电池的第一拐点电量Q_HVTP，可以获得当前老化状态下的所述电池的第一拐点电量Q_HVTP的准确值，从而可避免因电池老化引起所述第一拐点电量Q_HVTP发生变化而导致所述电池的当前容量Qnow计算不准确，有利于提高所述电池容量计算的准确性。
此外，还可以理解的是，不同的用户对电池的充放电有不同的使用习惯。一些用户习惯于在电池放电至较低的SOC段之后再对电池进行充电，或者偶尔在电池放电至较低的SOC段之后再对电池进行充电，如此，该电池在充电过程中所述第二拐点可以经常触发或偶尔触发，基于上述实施例中的所述第一拐点电量Q_HVTP的校正方法，该电池的所述第一拐点电量Q_HVTP可以根据所述第二拐点电量Q_LVTP、所述第一充入电量Qch_HVTP以及所述第三充入电量Qch_LVTP进行及时校正。然而，还有一些用户习惯于在电池放电至较低的SOC段之前即对电池进行充电，使得该电池在充电过程中所述第二拐点可能长时间未触发，进而使得所述第一拐点电量Q_HVTP将不能够根据所述第二拐点电量Q_LVTP、所述第一充入电量Qch_HVTP以及所述第三充入电量Qch_LVTP进行及时校正。
为了满足不同用户对电池充放电的使用习惯，在另一些实施例中，所述电池容量确定方法还包括：在所述第一拐点电量距离上一次校正的时间大于预设时间，且确定的所述目标拐点只包括所述第一拐点时，根据预设的所述第一拐点电量随时间变化的经验公式校正所述第一拐点电量。
其中，所述预设时间可以根据所述电池的老化速度进行设定，例如，对于老化速度较慢的电池，所述预设时间可以是8个月、10个月或者1年，而对于老化速度较快的电池，所述预设时间可以是4个月、5个月或者6个月，所述预设时间可以根据所述电池的具体老化速度进行设定，对此不作限定。
具体地，在本发明的实施例中，将所述第一拐点电量Q_HVTP距离上一次校正的时间定义为ΔT，所述第一拐点电量Q_HVTP随时间变化的经验公式定义为f(ΔT)，校正后的所述第一拐点电量定义为Q_HVTP_ΔT，所述第一拐点电量Q_HVTP、所述经验公式f(ΔT)以及校正后的所述第一拐点电量定义为Q_HVTP_ΔT满足关系式：
Q_HVTP_ΔT＝Q_HVTP-f(ΔT)。
其中，本领域普通技术人员悉知的是，对于不同批次及不同规格的电池而言，所述第一拐点电量Q_HVTP随时间变化的经验公式定义为f(ΔT)不同，而对于确定批次及规格的电池而言，所述第一拐点电量Q_HVTP随时间变化的经验公式定义为f(ΔT)可以经过多次测试得出，在此不做赘述。
如上所述，对于充电过程中所述第二拐点长时间不触发的电池，可以根据上一次校正的所述第一拐点电量Q_HVTP以及测试获得的所述第一拐点电量Q_HVTP随时间变化的经验公式定义为f(ΔT)对所述第一拐点电量Q_HVTP进行校正，如此，也可以避免因电池老化引起所述第一拐点电量Q_HVTP发生变化且所述第一拐点电量Q_HVTP未基于触发的所述第二拐点对应的所述第二拐点电量Q_LVTP进行及时校正导致的所述电池的当前容量Qnow计算不准确，提高所述电池状态计算的准确性。
基于上述两种对所述第一拐点电量Q_HVTP进行校正的方法，本发明实施例的所述电池容量确定方法可以满足不同用户对电池充放电的不同使用习惯。可以理解的是，不管是基于哪一种校正方法，校正后的所述第一拐点电量Q_HVTP以及所述第一拐点电量Q_HVTP的校正时间均可以存储于可读存储介质中，例如前述的BMS包含的NVM或者其他软件中，以便于下一次计算所述电池的状态。
进一步地，在本发明的实施例中，所述电池容量确定方法还包括：获取所述电池的初始容量；根据所述电池的当前容量和所述电池的初始容量计算所述电池的SOHC。具体地，将所述电池的初始容量定义为Qnew，所述电池的SOHC、所述电池的当前容量Qnow及所述电池的初始容量Qnew满足关系式：SOHC＝Qnow/Qnew*100％。
其中，可选地，为消除随机误差，即随机原因如温度、电流或系统算法误差等引起的所述电池的当前容量的计算误差，可以获取前n次计算的所述电池的当前容量，并根据n次计算的所述电池的当前容量计算加权后的所述电池的当前容量Qnow，以及根据加权后的所述电池的当前容量Qnow计算所述电池的SOHC。具体地，可以根据以下公式计算加权后的所述电池的当前容量Qnow：
Qnow＝n 1Qnow 1+n 2Qnow 2+…+n nQnow n。
其中，Qnow为加权后的所述电池的当前容量，Qnow 1至Qnow n为n次计算的所述电池的当前容量，n 1-n n为n次所述电池的当前容量对应的权重参数，n 1+n 2+…n n＝1，n 1-n n的具体取值可结合所述电池的历史数据和当前工况进行设定，对此不作限定。
在计算得到加权后的所述电池的当前容量Qnow后，再根据前述SOHC的计算公式计算所述电池的SOHC，计算结果更加准确。
下面以电动汽车的动力电池为例，对本发明实施例中的所述电池容量确定方法进行举例说明，所述电池容量确定方法被执行时的主要包括以下步骤：
第一步，电池出厂后，将相同规格的待检测电池抽取部分作为参考电池，将所述参考电池的电量放空后再恒流充至满电状态，记录所述参考电池充电过程中的电压-容量曲线(即前述第二充电曲线)，通过分析充电电压曲线特性，以获得所述电池的高电压平台拐点(即所述第一拐点)对应的第一拐点电压及第一拐点电量Q_HVTP、以及所述电池的低电压平台拐点(即所述第二拐点)对应的第二拐点电压及第二拐点电量Q_LVTP，其中，所述第一拐点Q_HVTP将存储于BMS的NVM中，所述第二拐点电量Q_LVTP为定值写入BMS的相应软件中，以便于快速调用实现后续的计算。
第二步，对实车应用中未知SOC状态的待测电池开始充电，实时记录所述电池充电开始 后的电压-容量曲线(即前述第一充电曲线)，根据所述第一充电曲线以及第一步中获得的所述第一拐点电压和所述第二拐点电压确定所述电池的目标拐点；其中，在所述电池的充电过程中，实时获取所述电池在充电至各个节点时的充入电量，包括所述电池充电至所述第一拐点时的第一充入电量Qch_HVTP、所述电池充电完成时的第二充入电量Qch_End及所述电池充电至所述第二拐点时的第三充入电量Qch_LVTP。
第三步，充电完成后，根据确定的所述目标拐点以及所述目标拐点对应的充入电量，对所述第一拐点电量Q_HVTP进行校正更新，具体的校正方法为：1、如果同时检测到所述第一拐点(HVTP)和所述第二拐点(LVTP)，则根据所述第二拐点电量Q_LVTP、所述第一充入电量Qch_HVTP及所述第三充入电量Qch_LVTP校正所述第一拐点电量Q_HVTP，并且将其更新时刻存储于NVM用于后续的计算；2、如果未检测到所述第二拐点(LVTP)且距离所述第一拐点电量Q_HVTP上一次的更新时间超过预设时间，则按经验公式f(ΔT)校正所述第一拐点电量Q_HVTP并将其更新时刻存储于NVM用于后续的计算；其中，上述两种校正方法更详细的内容可以参见前述相关内容，在此不再赘述。
第四步，在所述电池充电至满充状态后，则计算所述电池的当前容量Qnow，在计算得到所述电池的当前容量Qnow后，根据所述电池的当前容量进一步计算所述电池SOHC。需要说明的是，所述电池的当前容量Qnow以及所述电池的SOHC的详细计算方法可以参见前述相关内容，在此也不再赘述。
可以理解的是，一般用于电动汽车的电池在其容量衰减大于20％时就需要进行更换，因此电动汽车所使用的电池至少能检测位于较高的SOC段的高电压平台拐点(第一拐点)，使得本发明实施例的电池容量确定方法尤其适用于电动汽车的动力电池。
总而言之，根据本发明实施例的所述电池容量确定方法来计算电池的状态时，无需在充电前对电池进行深度放电，避免了满充或者满放对电池自身造成损耗，有利于提高电池的寿命和充电安全；再者，计算电池的当前容量时，只需检测电池充电至第一拐点(即高电压平台拐点)时的第一充入电量及电池充电完成时的第二充入电量，即可结合电池的第一拐点电量(即高电压平台拐点特征容量)快速计算电池的容量，而且无需进行SOC的区间选取，相较于选取特定SOC区间进行充电或放电计算电池容量，能够避免SOC估算不准对电池状态计算造成的误差，从而提高了电池容量计算的准确性。此外，在确定的目标拐点包括第一拐点和第二拐点(即低电压平台拐点)时，还可以根据第二拐点电量(即低电压平台拐点特征容量)、第一充入电量及电池充电至第二拐点的第三充入电量校正第一拐点电量，而在确定的目标拐点只包括第一拐点且第一拐点电量距离上一次校正的时间大于预设时间时，可以根据预设的第一拐点电量随时间变化的经验公式来校正第一拐点电量；如此，通过及时校正第一拐点电量，可以避免因电池老化引起第一拐点电量发生变化而导致电池的当前容量计算不准确，有利于提高电池状态计算的准确性，而且第一拐点电量具备两种校正方法，可以使本发明实施例的电池容量确定方法满足不同用户对电池充放电的不同使用习惯。
本发明第二方面实施例的非临时性计算机可读存储介质，其上存储有计算机程序，所述计算机程序被执行时实现上述任一实施例提到的电池容量确定方法。
根据本发明实施例的非临时性计算机可读存储介质，通过执行其存储的计算机程序，能够大大提高电池容量计算的速度和准确性。
图3为本发明第三方面实施例的电池容量确定装置1的功能框图，如图3所示，本发明提供的所述电池容量确定装置1包括至少一个处理器10和与所述至少一个处理器10通信连接的存储器20，其中，所述存储器20上存储有可被所述至少一个处理器10处理的指令，所述指令被 所述至少一个处理器10处理时实现上述任一实施例提到的电池容量确定方法。
根据本发明实施例的电池容量确定装置1，通过其处理器10执行上述任一实施例提到的电池容量确定方法，能够大大提高电池容量计算的速度和准确性。
需要说明的是，提供一种电池，所述电池的容量可采用上述任一实施例提到电池容量确定方法进行计算。根据本发明实施例的电池，通过上述的电池容量确定方法来计算其当前容量，能够大大提高电池容量计算的速度和准确性。
在本发明的描述中，参考术语“实施例”、“具体实施例”、“示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
尽管已经示出和描述了本发明的实施例，本领域的普通技术人员可以理解：在不脱离本发明的原理和宗旨的情况下可以对这些实施例进行多种变化、修改、替换和变型，本发明的范围由权利要求及其等同物限定。

Claims (20)

  1. 一种电池容量确定方法，其特征在于，包括：
    获取(S1)电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量，所述第一拐点电压大于所述第二拐点电压；
    控制(S2)所述电池进行充电，并实时记录所述电池的第一充电曲线；
    根据所述第一充电曲线确定(S3)目标拐点；
    检测(S4)所述电池的电量直至充电完成，获取所述电池充电至第一拐点时的第一充入电量和所述电池充电完成时的第二充入电量；
    在确定的所述目标拐点包括所述第一拐点时，根据所述第一拐点电量、所述第一充入电量以及所述第二充入电量计算所述电池的当前容量；
    其中，所述第一拐点电量、所述第一充入电量、所述第二充入电量和所述电池当前容量分别定义为Q_HVTP、Qch_HVTP、Qch_End和Qnow，Q_HVTP、Qch_HVTP、Qch_End以及Qnow满足关系式：Qnow＝Q_HVTP+Qch_End-Qch_HVTP。
  2. 如权利要求1所述的电池容量确定方法，其特征在于，所述电池容量确定方法还包括：
    在确定的所述目标拐点还包括第二拐点时，获取(S6)所述电池充电至所述第二拐点时的第三充入电量，并根据所述第二拐点电量、所述第一充入电量及所述第三充入电量校正所述第一拐点电量；
    其中，所述第二拐点电量和所述第三充入电量分别定义为Q_LVTP和Qch_LVTP，
    Q_HVTP、Qch_HVTP、Q_LVTP以及Qch_LVTP满足关系式：
    Q_HVTP＝Q_LVTP+Qch_HVTP-Qch_LVTP。
  3. 如权利要求1所述的电池容量确定方法，其特征在于，所述电池容量确定方法还包括：
    在确定的所述目标拐点只包括所述第一拐点时，如果当前时间距离所述第一拐点电量的上一次校正的时间大于预设时间，则根据预设的所述第一拐点电量随时间变化的经验公式校正所述第一拐点电量。
  4. 如权利要求1-3中任一项所述的电池容量确定方法，其特征在于，所述根据所述第一充电曲线确定目标拐点，包括：
    获取所述第一充电曲线的电压差分曲线；
    获取所述电压差分曲线的极大值点对应的峰值电压；以及
    比较所述峰值电压与所述第一拐点电压和所述第二拐点电压，以确定所述目标拐点。
  5. 如权利要求4所述的电池容量确定方法，其特征在于，所述比较所述峰值电压与所述第一拐点电压和所述第二拐点电压，以确定所述目标拐点，包括：
    若所述峰值电压大于所述第一拐点电压，则所述极大值点为目标拐点，且所述目标拐点为所述第一拐点；或者，若所述峰值电压小于所述第二拐点电压，则所述极大值点为目标拐点，且所述目标拐点为第二拐点。
  6. 如权利要求5所述的电池容量确定方法，其特征在于，所述比较所述峰值电压与所述第一拐点电压和所述第二拐点电压，以确定所述目标拐点，还包括：
    若所述峰值电压既不大于第一拐点电压也不小于第二拐点电压，则继续对所述电池充电并寻找目标拐点。
  7. 如权利要求4-6中任一项所述的电池容量确定方法，其特征在于，所述第一充电曲线为根据所述电池在充电过程中的第一电压数据及其对应的第一容量数据建立的电压-容量特性曲线，所述获取所述第一充电曲线的电压差分曲线，包括：
    对所述第一充电曲线进行平滑滤波处理，并对所述第一电压数据关于所述第一容量数据进行一阶求导，获得所述第一电压数据关于所述第一容量数据的变化率，根据所述变化率与所述第一容量数据建立所述第一充电曲线的电压差分曲线。
  8. 如权利要求1-7中任一项所述的电池容量确定方法，其特征在于，所述获取电池的第一拐点电压及其对应的第一拐点电量、第二拐点电压及其对应的第二拐点电量，包括：
    获取所述电池的第二充电曲线；
    根据所述第二充电曲线确定所述第一拐点和所述第二拐点；以及
    获取所述第一拐点对应的所述第一拐点电压、所述第一拐点电量，以及所述第二拐点对应的所述第二拐点电压、所述第二拐点电量。
  9. 如权利要求8所述的电池容量确定方法，其特征在于，所述获取所述电池的第二充电曲线，包括：
    确定一个或多个参考电池；
    将所述参考电池放空后再进行恒流充电；
    记录所述恒流充电过程中的第二容量数据及对应的第二电压数据；以及
    根据所述第二容量数据以及对应的所述第二电压数据建立电压-容量特性曲线，从而获得所述第二充电曲线。
  10. 如权利要求1-9中任一项所述的电池容量确定方法，其特征在于，所述电池容量确定方法还包括：
    获取所述电池的初始容量；以及
    根据所述电池的当前容量和所述电池的初始容量计算所述电池的电池容量健康状态 (SOHC)。
  11. 如权利要求1-10中任一项所述的电池容量确定方法，其特征在于，所述实时记录所述电池的第一充电曲线，包括：
    通过电池管理系统(BMS)采集和记录所述电池以下参数中的至少一个：电压、电流、温度、当前次充电时间、和充入电量；以及
    根据BMS充电算法获取所述第一充电曲线。
  12. 如权利要求1-11中任一项所述的电池容量确定方法，其特征在于，所述第一电量小于所述第二电量。
  13. 如权利要求1-12中任一项所述的电池容量确定方法，其特征在于，所述第一拐点电压和所述第一拐点电量为所述第二充电曲线中的高电压平台拐点对应的电压及拐点电量。
  14. 如权利要求1-13中任一项所述的电池容量确定方法，其特征在于，所述第二拐点电压和所述第二拐点电量为所述第二充电曲线中的低电压平台拐点对应的电压及拐点电量。
  15. 如权利要求1-14中任一项所述的电池容量确定方法，其特征在于，所述电池容量确定方法还包括：
    获取前n次计算的所述电池的当前容量，并根据所述前n次计算的所述电池的当前容量计算加权后的所述电池的当前容量。
  16. 如权利要求15所述的电池容量确定方法，其特征在于，根据所述加权后的所述电池的当前容量和所述电池的初始容量计算所述电池的电池容量健康状态(SOHC)。
  17. 如权利要求1-16中任一项所述的电池容量确定方法，其特征在于，所述获取所述电池充电至所述第二拐点时的第三电量，包括：
    通过电池管理系统(BMS)获取所述电池充电至所述第二拐点时的第三电量。
  18. 如权利要求1-17中任一项所述的电池容量确定方法，其特征在于，所述电池容量确定方法可以用于计算电池的容量。
  19. 一种非临时性计算机可读存储介质，其上存储有计算机程序，其特征在于，所述计算机程序被执行时实现如权利要求1-18中任一项所述的电池容量确定方法。
  20. 一种电池容量确定装置(1)，其特征在于，包括：
    至少一个处理器(10)；以及
    与所述至少一个处理器(10)通信连接的存储器(20)；其中，所述存储器(20)上存储有可以被所述至少一个处理器(10)处理的指令，所述指令被所述至少一个处理器(10)处理时实现如权利要求1-18中任一项所述的电池容量确定方法。
PCT/CN2022/118757 2022-03-29 2022-09-14 电池容量确定方法和装置、以及存储介质 Ceased WO2023184880A1 (zh)

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