WO2023077802A1 - 一种电池容量特征提取方法 - Google Patents

一种电池容量特征提取方法 Download PDF

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WO2023077802A1
WO2023077802A1 PCT/CN2022/097986 CN2022097986W WO2023077802A1 WO 2023077802 A1 WO2023077802 A1 WO 2023077802A1 CN 2022097986 W CN2022097986 W CN 2022097986W WO 2023077802 A1 WO2023077802 A1 WO 2023077802A1
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charging
state
charge
voltage
driving
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French (fr)
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王辰
王泽兴
宗磊
邹广才
原诚寅
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Beijing National New Energy Vehicle Technology Innovation Center Co Ltd
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Beijing National New Energy Vehicle Technology Innovation Center Co Ltd
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/12—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to state of charge [SoC]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/16—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to battery ageing, e.g. to the number of charging cycles or the 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]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • 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
    • G01R31/388—Determining ampere-hour charge capacity or SoC involving voltage measurements

Definitions

  • the invention belongs to the technical field of power batteries, and more specifically relates to a battery capacity feature extraction method.
  • the power battery is an important part of the new energy vehicle, so it is very necessary to know the data characteristics of the power battery charging process, driving process, and parking process.
  • the data features that characterize the power battery charging process, driving process, and parking process are mainly Battery capacity characteristics, including capacity decay rate ( SOHC ), internal resistance aging ( SOHR ).
  • SOHC capacity decay rate
  • SOHR internal resistance aging
  • the current mainstream SOH C estimation method is to estimate the current maximum remaining capacity under full SOC based on the difference between the ampere-hour integral and the state of charge (SOC), and then estimate the SOHC of the battery, while the state of charge (SOC) It is obtained based on the equivalent circuit model and the initial test parameters of the battery.
  • SOC state of charge
  • SOH estimation needs to accurately extract the current and SOC of the sampling point at each time, but because of the large deviation between the actual internal resistance and capacity of the battery at the end of its life and the test parameters, and the poor consistency of the battery cell, it is impossible to obtain an accurate SOC. Therefore, SOHC cannot be calculated accurately.
  • the object of the present invention is to propose a method that can accurately calculate SOHC and calculate the accurate SOC required for SOHR .
  • the present invention provides a battery capacity feature extraction method, including: acquiring the state of charge at each moment during the charging process and discharging process of the power battery during which the current is less than the current threshold and the drive motor torque is less than the torque threshold , total voltage, the lowest value of the battery cell voltage and the highest value of the battery cell voltage; based on the state of charge and the total voltage at each moment, the table of the total voltage and the state of charge is obtained; based on the state of charge at each moment, the battery cell The lowest value of the body voltage and the highest value of the battery cell voltage are obtained to obtain the battery cell voltage and state of charge table; based on the total voltage and state of charge table, the first-order internal resistance table of the charging process and the first-order internal resistance table of the driving process are obtained. Resistance meter; based on the battery cell voltage and state of charge table, the charge capacity decay rate is obtained.
  • the table of total voltage and state of charge is obtained through the following steps: take the state of charge as the abscissa, draw the first coordinate system with the total voltage as the ordinate, and compare the state of charge and the total state of charge at each moment
  • the voltage is marked in the first coordinate system; the marked points are sequentially connected to obtain a first curve, and the first curve is fitted, and a table of total voltage and state of charge is obtained according to the fitted relational expression.
  • the battery cell voltage and state of charge table is obtained through the following steps: take the state of charge as the abscissa, draw the second coordinate system with the cell voltage as the ordinate, and plot the charge at each moment
  • the state, the lowest value of the battery cell voltage and the highest value of the battery cell voltage are marked in the second coordinate system; the marked points are sequentially connected to obtain the second curve, and the second curve is fitted, and according to The relational expression of the battery cell voltage and state of charge is obtained.
  • the first-order internal resistance table of the charging process is obtained through the following steps: calculating the first-order internal resistance value of the charging process under different first initial charge states, charging currents, cycle times, and charging static voltages, wherein, the The charging static voltage is the average value of the voltage in the static state before charging or charging; establish the first-order internal resistance value of the charging process and its corresponding first initial state of charge, charging current, number of cycles, charging static A first relationship table of voltages; based on the total voltage and state of charge table, using the charging static voltage as the total voltage to obtain a first modified state of charge corresponding to the charging static voltage; using the first relationship The first initial state of charge in the table is changed to the corrected state of charge to obtain the first-order internal resistance table of the charging process.
  • the following formula is used to calculate the first-order internal resistance value of the charging process:
  • tcharge_start-1 is the moment before the charging starts
  • tcharge_start is the charging start moment
  • tcharge_end is the charging end moment
  • t drive_start +1 is the moment after the charging end
  • I is the charging current.
  • the first-order internal resistance table of the driving process is obtained through the following steps: calculating the first-order internal resistance value of the driving process under different second initial charge states, discharge currents, cycle times, and driving static voltages, wherein the The driving static voltage is the average value of the voltage in the static state before stopping driving or driving; establish the first-order internal resistance value of the driving process and its corresponding second initial state of charge, discharge current, number of cycles, and driving static voltage
  • the second relationship table based on the total voltage and state of charge table, the driving static voltage is used as the total voltage to obtain a second modified state of charge corresponding to the driving static voltage; the second relationship table The second initial state of charge in is modified to the second revised state of charge, and the first-order internal resistance table of the driving process is obtained.
  • the following formula is used to calculate the first-order internal resistance value of the driving process:
  • the charge capacity decay rate is obtained through the following steps: based on the battery cell voltage and state of charge table and the lowest value of the battery cell voltage in the resting state before the start of charging, determine the state of charge in the resting state before the start of charging; Based on the battery cell voltage and state of charge table and the highest value of the battery cell voltage in the resting state at the end of charging, determine the state of charge in the resting state after charging; based on the state of charge of the power battery at each moment, Determine the time of resting state before charging and the time of resting state after charging; calculate the charge capacity decay rate based on the time of resting state before charging and the time of resting state after charging.
  • the charging capacity decay rate is calculated using the following formula:
  • SOC charge_start is the state of charge in the state of rest before the start of charging
  • SOC charge_end is the state of charge in the state of rest after the end of charging , is the moment of resting state before charging starts, is the static state at the end of charging
  • Q now is the current maximum available capacity of the battery
  • Q ini is the initial maximum available capacity of the battery
  • SOH c1 is the decay rate of the charging capacity
  • i is the current.
  • the discharge capacity decay rate is calculated using the following formula:
  • SOH c2 is the decay rate of the discharge capacity
  • M drive_end is the driving end mileage
  • M drive_start is the driving start mileage
  • M NEDC is the cruising range.
  • the beneficial effect of the present invention is that: the battery capacity feature extraction method of the present invention does not need the test data of the battery before getting on the vehicle, and only uses the driving data and the characteristics of the charging and discharging states of the vehicle in different time periods to determine the SOH C , the SOH C Accurate, according to the OCV-SOC table to correct the first-order internal resistance table during the charging process and the first-order internal resistance table during the driving process, to provide accurate internal resistance value and SOC for calculating SOH R.
  • Fig. 1 shows a flowchart of a method for extracting battery capacity features according to an embodiment of the present invention.
  • Fig. 2 shows a table diagram of the total voltage and the state of charge of the battery capacity feature extraction method according to an embodiment of the present invention.
  • Fig. 3 shows a table diagram of battery cell voltage and state of charge according to a battery capacity feature extraction method according to an embodiment of the present invention.
  • Fig. 4 shows another flow chart of the battery capacity feature extraction method according to an embodiment of the present invention.
  • a battery capacity feature extraction method comprising: acquiring the state of charge, total voltage, battery The lowest value of cell voltage and the highest value of battery cell voltage; based on the state of charge and total voltage at each moment, the table of total voltage and state of charge is obtained; based on the state of charge at each moment, the minimum value of battery cell voltage and The highest value of the battery cell voltage, obtain the battery cell voltage and state of charge table; based on the total voltage and charge state table, obtain the first-order internal resistance table during the charging process and the first-order internal resistance table during the driving process; based on the battery cell Voltage and state of charge table to obtain the charge capacity decay rate.
  • the total voltage OCV table and the cell voltage OCV table under different SOCs are obtained, that is, the total voltage and state of charge table and the battery cell voltage and state of charge table, which are recorded as “total voltage SOC-OCV table” and "battery cell voltage SOC-OCV table”.
  • the corrected SOC is obtained, and then the charging is modified.
  • the first order internal resistance table of the process and the SOC in the first order internal resistance table of the driving process Through the battery cell voltage SOC-OCV table, the state of charge in the resting state before charging and the state of charge in the resting state after charging are obtained, and the charging capacity decay rate is calculated.
  • the battery capacity feature extraction method does not require the test data of the battery before getting on the vehicle, but only uses the driving data and the characteristics of the charging and discharging states of the vehicle in different time periods to determine the SOHC .
  • the SOHC is accurate, according to The OCV-SOC table corrects the first-order internal resistance table during the charging process and the first-order internal resistance table during the driving process to provide accurate internal resistance values and SOC for calculating SOH R.
  • the table of total voltage and state of charge is obtained through the following steps: take the state of charge as the abscissa and the total voltage as the ordinate to draw the first coordinate system, and mark the state of charge and the total voltage at each moment in In the first coordinate system; connect the marked points in sequence to obtain the first curve, and fit the first curve, and obtain the total voltage and state of charge table according to the fitted relationship, also called "total voltage SOC-OCV surface".
  • the battery cell voltage and state of charge table is obtained through the following steps: the state of charge is taken as the abscissa, and the cell voltage is used as the ordinate to draw the second coordinate system, and the state of charge, battery The lowest value of the cell voltage and the highest value of the battery cell voltage are marked in the second coordinate system; the marked points are connected in turn to obtain the second curve, and the second curve is fitted, and the battery cell is obtained according to the fitted relational expression.
  • Body voltage and state of charge table is taken as the abscissa, and the cell voltage is used as the ordinate to draw the second coordinate system, and the state of charge, battery
  • the lowest value of the cell voltage and the highest value of the battery cell voltage are marked in the second coordinate system; the marked points are connected in turn to obtain the second curve, and the second curve is fitted, and the battery cell is obtained according to the fitted relational expression.
  • Body voltage and state of charge table is obtained through the following steps: the state of charge is taken as the abscissa, and the cell voltage is used
  • the first-order internal resistance table of the charging process is obtained through the following steps: calculating the first-order internal resistance value of the charging process under different first initial state of charge, charging current, number of cycles, and charging static voltage, wherein, The charging static voltage is the average value of the voltage in the static state before charging or charging; establish the first-order internal resistance value of the charging process and its corresponding first initial state of charge, charging current, number of cycles, and the first value of the charging static voltage A relational table; based on the total voltage and state of charge table, using the charging static voltage as the total voltage to obtain a first revised state of charge corresponding to the charging static voltage; modifying the first initial state of charge in the first relational table to Correct the state of charge and obtain the first-order internal resistance table of the charging process.
  • the SOC corresponding to the "first-order internal resistance table in the charging process” is corrected through the "total voltage SOC-OCV table".
  • the specific method is to use the static voltage before the charging start point as the OCV voltage, and compare the "total voltage SOC-OCV table” to obtain the corrected SOC of the charging start process, and replace the corrected SOC of the charging start process with that of the charging process. SOC from the first-order internal resistance table.
  • the time of the first row is recorded as t start
  • the time of the last row is recorded as t end
  • the initial capacity is recorded as Q ini , according to the formula
  • the moment when charging is an integer multiple of the initial capacity is intercepted, and this moment is taken as the initial moment of the cycle, and the last line of time data is used as the end moment of the previous cycle. If the lack of charging data is serious, the number of cycles will be calculated in kilometers.
  • the charging event and the driving event are included in each cycle according to the time interval of the cycle. If the charging or driving event spans the end time of the cycle, the number of cycles to which the event belongs is distinguished by the time ratio of the event in the two cycle cycles.
  • the following formula is used to calculate the first-order internal resistance value of the charging process:
  • tcharge_start-1 is the moment before the charging starts
  • tcharge_start is the charging start moment
  • tcharge_end is the charging end moment
  • t drive_start +1 is the moment after the charging end
  • I is the charging current.
  • the determination of the first-order internal resistance In every 50 cycles, search for the continuous recording time > 60s through the identification bits such as "total current”, “SOC”, “charging status” and “vehicle status”, and include charging The field of the start or end time point (t charge_start , t charge_end ). by formula
  • obtain the first-order internal resistance table of the driving process calculate the first-order internal resistance value of the driving process under different second initial state of charge, discharge current, number of cycles, and driving static voltage, wherein the driving static voltage is Stop driving or the average value of the voltage in the static state before driving; establish the first-order internal resistance value of the driving process and the second relationship table corresponding to the second initial state of charge, discharge current, number of cycles, and driving static voltage; Based on the total voltage and state of charge table, the driving static voltage is taken as the total voltage to obtain the second modified state of charge corresponding to the driving static voltage; the second initial state of charge in the second relationship table is modified to the second modified state of charge To obtain the first-order internal resistance table of the driving process.
  • the SOC corresponding to the "first-order internal resistance table during driving” is corrected through the "total voltage SOC-OCV table".
  • the specific method is to use the static voltage before the starting point of driving as the OCV voltage, and obtain the corrected SOC of the driving starting process by referring to the "total voltage SOC-OCV table", and replace the corrected SOC of the driving starting process with that of the driving process. SOC from the first-order internal resistance table.
  • the following formula is used to calculate the first-order internal resistance value of the driving process:
  • the charging capacity decay rate is obtained through the following steps: Based on the battery cell voltage and state of charge table and the lowest value of the battery cell voltage in the resting state before the start of charging, determine the state of charge in the resting state before the start of charging ;Based on the battery cell voltage and state of charge table and the highest value of the battery cell voltage in the static state at the end of charging, determine the state of charge in the static state after charging; based on the state of charge of the power battery at each moment, determine The moment of resting state before charging starts and the moment of resting state after charging; based on the moment of resting state before charging and the moment of resting state after charging, the charging capacity decay rate is calculated.
  • SCC charge_start is the state of charge in the state of rest before the start of charging
  • SOC charge_end is the state of charge in the state of rest after the end of charging , is the moment of resting state before charging starts, is the static state at the end of charging
  • Q now is the current maximum available capacity of the battery
  • Q ini is the initial maximum available capacity of the battery
  • SOH c1 is the decay rate of the charging capacity
  • i is the current.
  • the discharge capacity decay rate is calculated using the following formula:
  • SOH c2 is the decay rate of the discharge capacity
  • M drive_end is the driving end mileage
  • M drive_start is the driving start mileage
  • M NEDC is the cruising range.
  • This application also extracts other characteristic data to calculate the characteristic sensitivity of capacity attenuation.
  • the specific steps are as follows:
  • DOD i , DOC j the depth of discharge and depth of charge for each driving event and charging event, denoted as DOD i , DOC j , where i and j refer to the i-th driving event and the j-th charging event, respectively.
  • the estimated capacity of a single vehicle under different cycle times is corrected as follows: regularize and normalize the above-mentioned characteristic sensitivity relationship, Decomposed to get the weight parameters of SOH c corrected by current, temperature, and charging depth under different cycle periods, denoted as The capacity decay rate of a single vehicle is recorded as If there are other features with greater sensitivity, they can also be added to this formula.
  • the acquisition method of battery aging characteristics is derived, and the sensitivity of aging characteristics is quantified by machine learning algorithm, so as to improve the accuracy of battery capacity decay rate estimation.
  • Fig. 1 shows a flowchart of a method for extracting battery capacity features according to an embodiment of the present invention.
  • Fig. 2 shows a table diagram of the total voltage and the state of charge of the battery capacity feature extraction method according to an embodiment of the present invention.
  • Fig. 3 shows a table diagram of battery cell voltage and state of charge according to a battery capacity feature extraction method according to an embodiment of the present invention.
  • Fig. 4 shows another flow chart of the battery capacity feature extraction method according to an embodiment of the present invention.
  • the battery capacity feature extraction method includes:
  • Step 1 Obtain the state of charge, total voltage, minimum value of battery cell voltage and maximum battery cell voltage at each moment during the charging process and discharging process of the power battery when the current is less than the current threshold and the torque of the driving motor is less than the torque threshold value;
  • Step 2 Obtain the table of total voltage and state of charge based on the state of charge and total voltage at each moment;
  • Step 3 Obtain the battery cell voltage and state of charge table based on the state of charge, the lowest value of the battery cell voltage and the highest value of the battery cell voltage at each moment;
  • Step 4 Obtain the first-order internal resistance table of the charging process and the first-order internal resistance table of the driving process based on the total voltage and state of charge table;
  • Step 5 Obtain the charge capacity decay rate based on the battery cell voltage and state of charge table.
  • the table of total voltage and state of charge is obtained through the following steps: the first coordinate system is drawn with the state of charge as the abscissa and the total voltage as the ordinate, and the state of charge and the total voltage at each moment are marked on the first In the coordinate system; connect the marked points in sequence to obtain the first curve, fit the first curve, and obtain the table of total voltage and state of charge according to the fitted relationship.
  • the battery cell voltage and state of charge table is obtained through the following steps: the state of charge is taken as the abscissa, the cell voltage is used as the ordinate to draw the second coordinate system, and the state of charge, battery cell The lowest value of the voltage and the highest value of the battery cell voltage are marked in the second coordinate system; the marked points are connected in turn to obtain the second curve, and the second curve is fitted, and the battery cell voltage is obtained according to the fitted relationship with state of charge table.
  • the first-order internal resistance table of the charging process is obtained through the following steps: calculating the first-order internal resistance value of the charging process under different first initial state of charge, charging current, cycle times, charging static voltage, wherein, charging static The voltage is the average value of the voltage in the static state before charging or charging; establish the first-order internal resistance value of the charging process and the corresponding first initial state of charge, charging current, number of cycles, and the first relationship between charging static voltage table; based on the total voltage and state of charge table, the charging static voltage is used as the total voltage to obtain the first revised state of charge corresponding to the charging static voltage; the first initial state of charge in the first relationship table is modified to the corrected state of charge According to the charging state, the first-order internal resistance table of the charging process is obtained.
  • tcharge_start-1 is the moment before the charging starts
  • tcharge_start is the charging start moment
  • tcharge_end is the charging end moment
  • t drive_start +1 is the moment after the charging end
  • I is the charging current.
  • the first-order internal resistance table of the driving process calculate the first-order internal resistance value of the driving process under different second initial state of charge, discharge current, cycle times, driving static voltage, wherein, the driving static voltage is stop driving Or the average value of the voltage in the static state before driving; establish the first-order internal resistance value of the driving process and the second relationship table corresponding to the second initial state of charge, discharge current, cycle times, and driving static voltage; based on the total Voltage and state of charge table, using the driving static voltage as the total voltage to obtain the second modified state of charge corresponding to the driving static voltage; modify the second initial state of charge in the second relationship table to the second modified state of charge , to obtain the first-order internal resistance table of the driving process.
  • the charging capacity decay rate is obtained through the following steps: based on the battery cell voltage and state of charge table and the lowest value of the battery cell voltage in the static state before the start of charging, determine the state of charge in the static state before the start of charging; The battery cell voltage and state of charge table and the highest value of the battery cell voltage in the static state at the end of charging determine the state of charge in the static state after charging; based on the state of charge of the power battery at each moment, determine the start of charging The moment of the static state before charging and the moment of the static state after the end of charging; based on the moment of the static state before the start of charging and the moment of the static state after the end of charging, the charging capacity decay rate is calculated.
  • SOC charge_start is the state of charge in the state of rest before the start of charging
  • SOC charge_end is the state of charge in the state of rest after the end of charging , is the moment of resting state before charging starts, is the static state at the end of charging
  • Q now is the current maximum available capacity of the battery
  • Q ini is the initial maximum available capacity of the battery
  • SOH c1 is the decay rate of the charging capacity
  • i is the current.
  • SOH c2 is the decay rate of the discharge capacity
  • M drive_end is the driving end mileage
  • M drive_start is the driving start mileage
  • M NEDC is the cruising range.

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Abstract

一种电池容量特征提取方法，包括：获取动力电池充电过程及放电过程电流小于电流阈值且驱动电机转矩小于转矩阈值时段内，每个时刻的荷电状态、总电压、电池单体电压最低值和电池单体电压最高值；基于每个时刻的荷电状态和总电压，获得总电压与荷电状态表；获得电池单体电压与荷电状态表；基于总电压与荷电状态表，获得充电过程的一阶内阻表和驾驶过程的一阶内阻表；基于电池单体电压与荷电状态表，获得充电容量衰减率。本发明通过车辆在不同时间周期下的充放电状态特征确定SOHC，该SOHC准确，依据OCV-SOC表修正充电过程的一阶内阻表和驾驶过程的一阶内阻表，为计算SOHR提供准确的内阻值及SOC。

Description

一种电池容量特征提取方法 技术领域
本发明属于动力电池技术领域，更具体地，涉及一种电池容量特征提取方法。
背景技术
动力电池是新能源汽车的重要部件，因此获知动力电池的充电过程、行驶过程以及停车过程中的数据特征是非常必要的，通常表征动力电池充电过程、行驶过程以及停车过程中的数据特征主要是电池容量特征，包括容量衰减率(SOH C)、内阻老化(SOH R)。但是因为动力电池老化机理复杂，影响因素众多，在动力电池使用过程中的电池容量衰减率(SOH C)、内阻老化(SOH R)难以估计。目前的主流的SOH C的估算方法是基于安时积分和荷电状态(SOC)差值进行全SOC下的当前最大剩余容量估算，并由此估算电池的SOH C，而荷电状态(SOC)是基于等效电路模型和电池初始测试参数获得的，但由于电池老化，电池的初始测试参数无法持续沿用到电池的全生命周期的SOC估算当中，因此SOC估算不准确。而电池的全生命周期SOC估算精度也决定电池SOH估算的准确度。SOH估算需要准确的提取每个时刻采样点的电流、SOC，但因为电池在生命后期其真实内阻以及容量与测试参数偏差较大以及电芯一致性变差等原因，无法取得准确的SOC，因此也无法准确计算SOH C。
由于电池内阻跟电池温度、充放电倍率以及SOC相关性较大，且数值较小难以估算，因此目前没有成熟的的SOH R估计算法。
因此，特别需要一种方法能准确计算SOH C和计算SOH R需要的准确的SOC。
发明内容
本发明的目的是提出一种方法能准确计算SOH C和计算SOH R需要的准确的SOC。
为了实现上述目的，本发明提供了一种电池容量特征提取方法，包括：获取动力电池充电过程及放电过程电流小于电流阈值且驱动电机转矩小于转矩阈值时段内，每个时刻的荷电状态、总电压、电池单体电压最低值和电池单体电压最高值；基于每个时刻的荷电状态和总电压，获得总电压与荷电状态表；基于每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值，获得电池单体电压与荷电状态表；基于所述总电压与荷电状态表，获得充电过程的一阶内阻表和驾驶过程的一阶内阻表；基于电池单体电压与荷电状态表，获得充电容量衰减率。
优选地，通过下述步骤获得总电压与荷电状态表：以所述荷电状态为横坐标，以所述总电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和总电压标注在所述第一坐标系中；将标注的点依次连接获得第一曲线，对所述第一曲线进行拟合，根据拟合后的关系式，获得总电压与荷电状态表。
优选地，通过下述步骤获得电池单体电压与荷电状态表：以所述荷电状态为横坐标，以所述单体电压为纵坐标绘制第二坐标系，将每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值标注在所述第二坐标系中；将标注的点依次连接获得第二曲线，对所述第二曲线进行拟合，根据拟合后的关系式，获得电池单体电压与荷电状态表。
优选地，通过下述步骤获得充电过程的一阶内阻表：计算在不同第一初始荷电状态、充电电流、循环次数、充电静态电压下的充电过程的一阶内阻值，其中，所述充电静态电压为停止充电或者充电前静置状态下的电压的平均值；建立所述充电过程的一阶内阻值及与其对应的第一初始荷电状态、充电电流、循环次数、充电静态电压的第一关系表；基于所述总电 压与荷电状态表，将所述充电静态电压作为总电压，获得与所述充电静态电压对应的第一修正荷电状态；将所述第一关系表中的第一初始荷电状态修改为修正荷电状态，获得充电过程的一阶内阻表。
优选地，采用下述公式计算充电过程的一阶内阻值：
Figure PCTCN2022097986-appb-000001
其中，
Figure PCTCN2022097986-appb-000002
为充电开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000003
为充电结束时刻一阶内阻值，
Figure PCTCN2022097986-appb-000004
为充电开始前一时刻电压，
Figure PCTCN2022097986-appb-000005
为充电开始时刻电压，
Figure PCTCN2022097986-appb-000006
为充电结束时刻电压，
Figure PCTCN2022097986-appb-000007
为充电结束后一时刻电压，t charge_start-1为充电开始前一时刻，t charge_start为充电开始时刻，t charge_end为充电结束时刻，t drive_start+1为充电结束后一时刻，I为充电电流。
优选地，通过以下步骤获得驾驶过程的一阶内阻表：计算在不同第二初始荷电状态、放电电流、循环次数、驾驶静态电压下的驾驶过程的一阶内阻值，其中，所述驾驶静态电压为停止驾驶或者驾驶前静置状态下的电压的平均值；建立所述驾驶过程的一阶内阻值及与其对应的第二初始荷电状态、放电电流、循环次数、驾驶静态电压的第二关系表；基于所述总电压与荷电状态表，将所述驾驶静态电压作为总电压，获得与所述驾驶静态电压对应的第二修正荷电状态；将所述第二关系表中的第二初始荷电状态修改为第二修正荷电状态，获得驾驶过程的一阶内阻表。
优选地，采用下述公式计算驾驶过程的一阶内阻值：
Figure PCTCN2022097986-appb-000008
Figure PCTCN2022097986-appb-000009
其中，
Figure PCTCN2022097986-appb-000010
为驾驶开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000011
为驾驶结束时刻 一阶内阻值，
Figure PCTCN2022097986-appb-000012
为驾驶开始前一时刻电压，
Figure PCTCN2022097986-appb-000013
为驾驶开始时刻电压，
Figure PCTCN2022097986-appb-000014
为驾驶结束时刻电压，
Figure PCTCN2022097986-appb-000015
为驾驶结束后一时刻电压，t drive_start-1为驾驶开始前一时刻，t drive_start为驾驶开始时刻，t drive_end为驾驶结束时刻，t drive_end+1为驾驶结束后一时刻，I为放电电流。
优选地，通过下述步骤获得充电容量衰减率：基于电池单体电压与荷电状态表和充电开始前静置状态的电池单体电压最低值，确定充电开始前静置状态的荷电状态；基于电池单体电压与荷电状态表和充电结束时静置状态的电池单体电压最高值，确定充电结束后静置状态的荷电状态；基于所述动力电池每个时刻的荷电状态，确定充电开始前静置状态的时刻和充电结束后静置状态的时刻；基于所述充电开始前静置状态的时刻和充电结束后静置状态的时刻，计算充电容量衰减率。
优选地，采用下述公式计算充电容量衰减率：
Figure PCTCN2022097986-appb-000016
其中，
Figure PCTCN2022097986-appb-000017
为充电开始前静置状态的时刻到充电开始后静置状态的时刻的累计容量值，SOC charge_start为充电开始前静置状态的荷电状态，SOC charge_end为充电结束后静置状态的荷电状态，
Figure PCTCN2022097986-appb-000018
为充电开始前静置状态的时刻，
Figure PCTCN2022097986-appb-000019
为充电结束时静置状态，Q now为当前电池最大可用容量，Q ini为电池初始最大可用容量，SOH c1为充电容量衰减率，i为电流。
优选的，采用下述公式计算放电容量衰减率：
Figure PCTCN2022097986-appb-000020
其中，SOH c2为放电容量衰减率，M drive_end为驾驶结束里程，M drive_start为驾 驶开始里程，M NEDC为里程续航。
本发明的有益效果在于：本发明的电池容量特征提取方法不需要电池在上车前的测试数据，只通过行车数据，通过车辆在不同时间周期下的充放电状态特征确定SOH C，该SOH C准确，依据OCV-SOC表修正充电过程的一阶内阻表和驾驶过程的一阶内阻表，为计算SOH R提供准确的内阻值及SOC。
附图说明
通过结合附图对本发明示例性实施方式进行更详细的描述，本发明的上述以及其它目的、特征和优势将变得更加明显。其中，在本发明示例性实施方式中，相同的附图标记通常代表相同部件。
图1示出了根据本发明的一个实施例的电池容量特征提取方法的流程图。
图2示出了根据本发明的一个实施例的电池容量特征提取方法的总电压与荷电状态表图。
图3示出了根据本发明的一个实施例的电池容量特征提取方法的电池单体电压与荷电状态表图。
图4示出了根据本发明的一个实施例的电池容量特征提取方法的又一流程图。
具体实施方式
下面将参照附图更详细地描述本发明的优选实施例。虽然附图中显示了本发明的优选实施例，然而应该理解，可以以各种形式实现本发明而不应被这里阐述的实施方式所限制。相反，提供这些实施方式是为了使本发明更加透彻和完整，并且能够将本发明的范围完整地传达给本领域的技术人员。
根据本发明的一种电池容量特征提取方法，包括：获取动力电池充电过程及放电过程电流小于电流阈值且驱动电机转矩小于转矩阈值时段内，每个时刻的荷电状态、总电压、电池单体电压最低值和电池单体电压最高值；基于每个时刻的荷电状态和总电压，获得总电压与荷电状态表；基于每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值，获得电池单体电压与荷电状态表；基于总电压与荷电状态表，获得充电过程的一阶内阻表和驾驶过程的一阶内阻表；基于电池单体电压与荷电状态表，获得充电容量衰减率。
具体的，截取所有充电过程及放电过程电流<0.1C且驱动电机转矩<20Nm的字段，记录该字段的SOC、总电压、电池单体电压最低值、电池单体电压最高值。通过整体数据遍历，获得不同SOC下的总电压OCV表和单体电压OCV表，即总电压与荷电状态表和电池单体电压与荷电状态表，记为“总电压SOC-OCV表”和“电池单体电压SOC-OCV表”。通过计算获得充电过程的一阶内阻表和驾驶过程的一阶内阻表后，根据充电静置电压和驾驶静置电压，基于总电压SOC-OCV表，获得修正后的SOC，进而修改充电过程的一阶内阻表和驾驶过程的一阶内阻表中的SOC。通过电池单体电压SOC-OCV表，获得充电开始前静置状态的荷电状态和充电结束后静置状态的荷电状态，计算获得充电容量衰减率。
根据示例性的实施方式，电池容量特征提取方法不需要电池在上车前的测试数据，只通过行车数据，通过车辆在不同时间周期下的充放电状态特征确定SOH C，该SOH C准确，依据OCV-SOC表修正充电过程的一阶内阻表和驾驶过程的一阶内阻表，为计算SOH R提供准确的内阻值及SOC。
作为优选方案，通过下述步骤获得总电压与荷电状态表：以荷电状态为横坐标，以总电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和总电压标注在第一坐标系中；将标注的点依次连接获得第一曲线，对第一曲线进行拟合，根据拟合后的关系式，获得总电压与荷电状态表，也叫做 “总电压SOC-OCV表”。
具体的，截取所有充电过程及放电过程电流<0.1C且驱动电机转矩<20Nm的字段，记录该字段的SOC、总电压、电池单体电压最低值、电池单体电压最高值。通过整体数据遍历，获得不同SOC下的总电压OCV，以荷电状态为横坐标，以总电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和总电压标注在第一坐标系中，将标记的点连成曲线，对曲线进行拟合，获得曲线的拟合关系，根据拟合关系，生成总电压与荷电状态表。
作为优选方案，通过下述步骤获得电池单体电压与荷电状态表：以荷电状态为横坐标，以单体电压为纵坐标绘制第二坐标系，将每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值标注在第二坐标系中；将标注的点依次连接获得第二曲线，对第二曲线进行拟合，根据拟合后的关系式，获得电池单体电压与荷电状态表。
具体的，截取所有充电过程及放电过程电流<0.1C且驱动电机转矩<20Nm的字段，记录该字段的SOC、总电压、电池单体电压最低值、电池单体电压最高值。通过整体数据遍历，获得不同SOC下的电池单体电压最低值和电池单体电压最高值，以荷电状态为横坐标，以电池单体电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和电池单体电压标注在第一坐标系中，将标记的点连成曲线，对曲线进行拟合，获得曲线的拟合关系，根据拟合关系，生成电池单体电压与荷电状态表，也叫做“电池单体电压SOC-OCV表”。
作为优选方案，通过下述步骤获得充电过程的一阶内阻表：计算在不同第一初始荷电状态、充电电流、循环次数、充电静态电压下的充电过程的一阶内阻值，其中，充电静态电压为停止充电或者充电前静置状态下的电压的平均值；建立充电过程的一阶内阻值及与其对应的第一初始荷电状态、充电电流、循环次数、充电静态电压的第一关系表；基于总电压与荷电状态表，将充电静态电压作为总电压，获得与充电静态电压对应的第一 修正荷电状态；将第一关系表中的第一初始荷电状态修改为修正荷电状态，获得充电过程的一阶内阻表。
具体的，通过“总电压SOC-OCV表”修正“充电过程的一阶内阻表”对应的SOC。具体方法是，在充电起始点之前的静置电压作为OCV电压，对照“总电压SOC-OCV表”获得修正的充电起始过程的SOC，将修正的的充电起始过程的SOC替换充电过程的一阶内阻表中的SOC。
首行时间记为t start，末尾行时间记为t end，初始容量记为Q ini，按照公式
Figure PCTCN2022097986-appb-000021
计算历史过程中的电池循环次数。
截取充电时为初始容量的整数倍的时刻，以该时刻作为该循环周期的初始时刻，上一行时间数据作为上一循环周期的结束时刻。若充电数据缺失严重，则以公里数计算循环次数。将充电事件和驾驶事件按照循环周期的时间间隔列入每一个循环周期中。若充电或者驾驶事件跨越循环的结束时刻，则以该次事件在两次循环周期下的时间占比来区分该次事件属于的循环周期数。
作为优选方案，采用下述公式计算充电过程的一阶内阻值：
Figure PCTCN2022097986-appb-000022
其中，
Figure PCTCN2022097986-appb-000023
为充电开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000024
为充电结束时刻一阶内阻值，
Figure PCTCN2022097986-appb-000025
为充电开始前一时刻电压，
Figure PCTCN2022097986-appb-000026
为充电开始时刻电压，
Figure PCTCN2022097986-appb-000027
为充电结束时刻电压，
Figure PCTCN2022097986-appb-000028
为充电结束后一时刻电压，t charge_start-1为充电开始前一时刻，t charge_start为充电开始时刻，t charge_end为充电结束时刻，t drive_start+1为充电结束后一时刻，I为 充电电流。
具体的，一阶内阻确定：在每50个循环周期内，通过“总电流”、“SOC”、“充电状态”、“车辆状态”等标识位检索连续记录时间>60s的，且包含充电开始或者结束时刻点(t charge_start，t charge_end)的字段。通过公式
Figure PCTCN2022097986-appb-000029
计算在不同SOC、充电电流、循环次数以及静态电压下的一阶内阻值，基于历史数据，形成“充电过程的一阶内阻表”，将车辆停止充电或者充电前静置状态下的电压的平均值记为静止电压。
作为优选方案，获得驾驶过程的一阶内阻表：计算在不同第二初始荷电状态、放电电流、循环次数、驾驶静态电压下的驾驶过程的一阶内阻值，其中，驾驶静态电压为停止驾驶或者驾驶前静置状态下的电压的平均值；建立驾驶过程的一阶内阻值及与其对应的第二初始荷电状态、放电电流、循环次数、驾驶静态电压的第二关系表；基于总电压与荷电状态表，将驾驶静态电压作为总电压，获得与驾驶静态电压对应的第二修正荷电状态；将第二关系表中的第二初始荷电状态修改为第二修正荷电状态，获得驾驶过程的一阶内阻表。
具体的，通过“总电压SOC-OCV表”修正“驾驶过程的一阶内阻表”对应的SOC。具体方法是，在驾驶起始点之前的静置电压作为OCV电压，对照“总电压SOC-OCV表”获得修正的驾驶起始过程的SOC，将修正的的驾驶起始过程的SOC替换驾驶过程的一阶内阻表中的SOC。
作为优选方案，采用下述公式计算驾驶过程的一阶内阻值：
Figure PCTCN2022097986-appb-000030
其中，其中，
Figure PCTCN2022097986-appb-000031
为驾驶开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000032
为驾驶结束时刻一阶内阻值，
Figure PCTCN2022097986-appb-000033
为驾驶开始前一时刻电压，
Figure PCTCN2022097986-appb-000034
为驾驶开始时刻电压，
Figure PCTCN2022097986-appb-000035
为驾驶结束时刻电压，
Figure PCTCN2022097986-appb-000036
为驾驶结束后一时刻电压，t drive_start-1为驾驶开始前一时刻，t drive_start为驾驶开始时刻，t drive_end为驾驶结束时刻，t diive_end+1为驾驶结束后一时刻，I为放电电流。
具体的，在每50个循环周期内，通过“总电流”、“SOC”、“充电状态”、“车辆状态”等标识位检索连续记录时间>60s的，且包含驾驶开始或者结束时刻点(t drive_start，t drive_end)的字段。通过公式
Figure PCTCN2022097986-appb-000037
计算在不同SOC、充电电流、循环次数以及静态电压下的一阶内阻值，基于历史数据，形成“驾驶过程的一阶内阻表”，将车辆停止驾驶或者驾驶前静置状态下的电压的平均值记为静止电压。
作为优选方案，通过下述步骤获得充电容量衰减率：基于电池单体电压与荷电状态表和充电开始前静置状态的电池单体电压最低值，确定充电开始前静置状态的荷电状态；基于电池单体电压与荷电状态表和充电结束时静置状态的电池单体电压最高值，确定充电结束后静置状态的荷电状态；基于动力电池每个时刻的荷电状态，确定充电开始前静置状态的时刻和充电结束后静置状态的时刻；基于充电开始前静置状态的时刻和充电结束后静置状态的时刻，计算充电容量衰减率。
作为优选方案，采用下述公式计算充电容量衰减率：
Figure PCTCN2022097986-appb-000038
其中，
Figure PCTCN2022097986-appb-000039
为充电开始前静置状态的时刻到充电结束后静置状态的时刻的累计容量值，SCC charge_start为充电开始前静置状态的荷电状态，SOC charge_end为充电结束后静置状态的荷电状态，
Figure PCTCN2022097986-appb-000040
为充电开始前静置状态的时刻，
Figure PCTCN2022097986-appb-000041
为充电结束时静置状态，Q now为当前电池最大可用容量，Q ini为电池初始最大可用容量，SOH c1为充电容量衰减率，i为电流。
具体的，在充电过程中的，通过“电池单体电压SOC-OCV表”和在充电开始前静置状态的电池单体电压最低值，确定充电起始时SOC，记为SOC charge_start。通过“电池单体电压SOC-OCV表”和充电结束时静置状态的电池单体电压最高值，确定充电结束时SOC，记为SCC charge_end。通过以下公式积分各个充电过程中的充电容量，并计算放电容量衰减率：
Figure PCTCN2022097986-appb-000042
作为优选方案，采用下述公式计算放电容量衰减率：
Figure PCTCN2022097986-appb-000043
其中，SOH c2为放电容量衰减率，M drive_end为驾驶结束里程，M drive_start为驾驶开始里程，M NEDC为里程续航。
具体的，记录每次驾驶事件开始里程和结束里程，记为M drive_start和 M drive_end。通过公式
Figure PCTCN2022097986-appb-000044
近似计算放电容量衰减率。
本申请还提取其他特征数据，计算容量衰减的特征敏感度，具体步骤如下：
随机抽取1000辆该款车型数据，进行以下特征提取工作：
1.按照电池循环次数的获取步骤完成容量估计点数据，并按每50次循环次数进行区分，记为SOH N,k，其中N＝50,100,150,…，k为车辆号，k＝1,2,…,1000。
2.记录每次驾驶事件、充电事件的电流中位数记为
Figure PCTCN2022097986-appb-000045
其中i和j分别指第i次驾驶和第j次充电事件。
3.记录每次驾驶事件、充电事件的温度中位数记为
Figure PCTCN2022097986-appb-000046
其中i和j分别指第i次驾驶和第j次充电事件。
4.记录每次驾驶事件、充电事件的放电深度和充电深度，记为DOD i、DOC j,其中i和j分别指第i次驾驶和第j次充电事件。
5.记录每次驾驶事件、充电事件的压差中位数，记为dV i、dV j,其中i和j分别指第i次驾驶和第j次充电事件。
6.记录每次驾驶事件、充电事件的温差中位数，记为dT i、dT j,其中i和j分别指第i次驾驶和第j次充电事件。
7.通过“充电过程的一阶内阻表”和“驾驶过程的一阶内阻表”记录每次驾驶事件、充电事件的一阶内阻，记为
Figure PCTCN2022097986-appb-000047
其中i和j分别指第i次驾驶和第j次充电事件。
8.提取其他特征，包括但不限于每次充电事件和驾驶事件的温度升高值、车速中位数、压差中位数、温差中位数等等。
9.按照每50次循环记录一下特征数据，通过随机森林或者其他机器学习类算法训练出不同循环下的容量衰减的特征敏感度模型，根据每个循环阶段下的模型计算特征重要性，以此计算出不同特征对容量衰减的影响程 度。最后，总结在不同循环下的容量衰减的特征敏感度的关系式，记为
Figure PCTCN2022097986-appb-000048
10.基于该款车1000辆车的数据获得的敏感度信息表，对被估计的单一车辆不同循环次数下的容量进行如下修正：将上述特征敏感度关系式进行正则化、归一化处理，分解得到不同循环周期下，通过电流、温度、充电深度修正SOH c的权重参数，记为
Figure PCTCN2022097986-appb-000049
单一车辆的容量衰减率记为
Figure PCTCN2022097986-appb-000050
若有其他特征的特征敏感度较大，也可添加进此公式。
至此，获得每次充电事件的若干特征和每次驾驶事件的若干特征。
推导电池老化特征的获取方法，并以机器学习算法量化老化特征敏感度，提高电池容量衰减率估算的精度。
实施例一
图1示出了根据本发明的一个实施例的电池容量特征提取方法的流程图。图2示出了根据本发明的一个实施例的电池容量特征提取方法的总电压与荷电状态表图。图3示出了根据本发明的一个实施例的电池容量特征提取方法的电池单体电压与荷电状态表图。图4示出了根据本发明的一个实施例的电池容量特征提取方法的又一流程图。
如图1、图2、图3和图4所示，该电池容量特征提取方法，包括：
步骤1：获取动力电池充电过程及放电过程电流小于电流阈值且驱动电机转矩小于转矩阈值时段内，每个时刻的荷电状态、总电压、电池单体电压最低值和电池单体电压最高值；
步骤2：基于每个时刻的荷电状态和总电压，获得总电压与荷电状态表；
步骤3：基于每个时刻的荷电状态、电池单体电压最低值和电池单体电 压最高值，获得电池单体电压与荷电状态表；
步骤4：基于总电压与荷电状态表，获得充电过程的一阶内阻表和驾驶过程的一阶内阻表；
步骤5：基于电池单体电压与荷电状态表，获得充电容量衰减率。
其中，通过下述步骤获得总电压与荷电状态表：以荷电状态为横坐标，以总电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和总电压标注在第一坐标系中；将标注的点依次连接获得第一曲线，对第一曲线进行拟合，根据拟合后的关系式，获得总电压与荷电状态表。
其中，通过下述步骤获得电池单体电压与荷电状态表：以荷电状态为横坐标，以单体电压为纵坐标绘制第二坐标系，将每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值标注在第二坐标系中；将标注的点依次连接获得第二曲线，对第二曲线进行拟合，根据拟合后的关系式，获得电池单体电压与荷电状态表。
其中，通过下述步骤获得充电过程的一阶内阻表：计算在不同第一初始荷电状态、充电电流、循环次数、充电静态电压下的充电过程的一阶内阻值，其中，充电静态电压为停止充电或者充电前静置状态下的电压的平均值；建立充电过程的一阶内阻值及与其对应的第一初始荷电状态、充电电流、循环次数、充电静态电压的第一关系表；基于总电压与荷电状态表，将充电静态电压作为总电压，获得与充电静态电压对应的第一修正荷电状态；将第一关系表中的第一初始荷电状态修改为修正荷电状态，获得充电过程的一阶内阻表。
其中，采用下述公式计算充电过程的一阶内阻值：
Figure PCTCN2022097986-appb-000051
其中，
Figure PCTCN2022097986-appb-000052
为充电开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000053
为充电结束时 刻一阶内阻值，
Figure PCTCN2022097986-appb-000054
为充电开始前一时刻电压，
Figure PCTCN2022097986-appb-000055
为充电开始时刻电压，
Figure PCTCN2022097986-appb-000056
为充电结束时刻电压，
Figure PCTCN2022097986-appb-000057
为充电结束后一时刻电压，t charge_start-1为充电开始前一时刻，t charge_start为充电开始时刻，t charge_end为充电结束时刻，t drive_start+1为充电结束后一时刻，I为充电电流。
其中，获得驾驶过程的一阶内阻表：计算在不同第二初始荷电状态、放电电流、循环次数、驾驶静态电压下的驾驶过程的一阶内阻值，其中，驾驶静态电压为停止驾驶或者驾驶前静置状态下的电压的平均值；建立驾驶过程的一阶内阻值及与其对应的第二初始荷电状态、放电电流、循环次数、驾驶静态电压的第二关系表；基于总电压与荷电状态表，将驾驶静态电压作为总电压，获得与驾驶静态电压对应的第二修正荷电状态；将第二关系表中的第二初始荷电状态修改为第二修正荷电状态，获得驾驶过程的一阶内阻表。
其中，采用下述公式计算驾驶过程的一阶内阻值：
Figure PCTCN2022097986-appb-000058
其中，其中，
Figure PCTCN2022097986-appb-000059
为驾驶开始时刻一阶内阻值，
Figure PCTCN2022097986-appb-000060
为驾驶结束时刻一阶内阻值，
Figure PCTCN2022097986-appb-000061
为驾驶开始前一时刻电压，
Figure PCTCN2022097986-appb-000062
为驾驶开始时刻电压，
Figure PCTCN2022097986-appb-000063
为驾驶结束时刻电压，
Figure PCTCN2022097986-appb-000064
为驾驶结束后一时刻电压，t drive_start-1为驾驶开始前一时刻，t drive_start为驾驶开始时刻，t drive_end为驾驶结束时刻，t drive_end+1为驾驶结束后一时刻，I为放电电流。
其中，通过下述步骤获得充电容量衰减率：基于电池单体电压与荷电状态表和充电开始前静置状态的电池单体电压最低值，确定充电开始前静置状态的荷电状态；基于电池单体电压与荷电状态表和充电结束时静置状态的电池单体电压最高值，确定充电结束后静置状态的荷电状态；基于动 力电池每个时刻的荷电状态，确定充电开始前静置状态的时刻和充电结束后静置状态的时刻；基于充电开始前静置状态的时刻和充电结束后静置状态的时刻，计算充电容量衰减率。
其中，采用下述公式计算充电容量衰减率：
Figure PCTCN2022097986-appb-000065
其中，
Figure PCTCN2022097986-appb-000066
为充电开始前静置状态的时刻到充电结束后静置状态的时刻的累计容量值，SOC charge_start为充电开始前静置状态的荷电状态，SOC charge_end为充电结束后静置状态的荷电状态，
Figure PCTCN2022097986-appb-000067
为充电开始前静置状态的时刻，
Figure PCTCN2022097986-appb-000068
为充电结束时静置状态，Q now为当前电池最大可用容量，Q ini为电池初始最大可用容量，SOH c1为充电容量衰减率，i为电流。
其中，采用下述公式计算放电容量衰减率：
Figure PCTCN2022097986-appb-000069
其中，SOH c2为放电容量衰减率，M drive_end为驾驶结束里程，M drive_start为驾驶开始里程，M NEDC为里程续航。
以上已经描述了本发明的实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的实施例。在不偏离所说明的实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。

Claims (10)

  1. 一种电池容量特征提取方法，其特征在于，包括：
    获取动力电池充电过程及放电过程电流小于电流阈值且驱动电机转矩小于转矩阈值时段内，每个时刻的荷电状态、总电压、电池单体电压最低值和电池单体电压最高值；
    基于每个时刻的荷电状态和总电压，获得总电压与荷电状态表；
    基于每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值，获得电池单体电压与荷电状态表；
    基于所述总电压与荷电状态表，获得充电过程的一阶内阻表和驾驶过程的一阶内阻表；
    基于所述电池单体电压与荷电状态表，获得充电容量衰减率。
  2. 根据权利要求1所述的电池容量特征提取方法，其特征在于，通过下述步骤获得所述总电压与荷电状态表：
    以所述荷电状态为横坐标，以所述总电压为纵坐标绘制第一坐标系，将每个时刻的荷电状态和总电压标注在所述第一坐标系中；
    将标注的点依次连接获得第一曲线，对所述第一曲线进行拟合，根据拟合后的关系式，获得所述总电压与荷电状态表。
  3. 根据权利要求2所述的电池容量特征提取方法，其特征在于，通过下述步骤获得所述电池单体电压与荷电状态表：
    以所述荷电状态为横坐标，以所述电池单体电压为纵坐标绘制第二坐标系，将每个时刻的荷电状态、电池单体电压最低值和电池单体电压最高值标注在所述第二坐标系中；
    将标注的点依次连接获得第二曲线，对所述第二曲线进行拟合，根据拟合后的关系式，获得所述电池单体电压与荷电状态表。
  4. 根据权利要求3所述的电池容量特征提取方法，通过下述步骤获得所述充电过程的一阶内阻表：
    计算在不同第一初始荷电状态、充电电流、循环次数、充电静态电压下的充电过程的一阶内阻值，其中，所述充电静态电压为停止充电或者充电前静置状态下的电压的平均值；
    建立所述充电过程的一阶内阻值及与其对应的第一初始荷电状态、充电电流、循环次数、充电静态电压的第一关系表；
    基于所述总电压与荷电状态表，将所述充电静态电压作为总电压，获得与所述充电静态电压对应的第一修正荷电状态；
    将所述第一关系表中的第一初始荷电状态修改为修正荷电状态，获得所述充电过程的一阶内阻表。
  5. 根据权利要求4所述的电池容量特征提取方法，其特征在于，采用下述公式计算所述充电过程的一阶内阻值：
    Figure PCTCN2022097986-appb-100001
    其中，
    Figure PCTCN2022097986-appb-100002
    为充电开始时刻一阶内阻值，
    Figure PCTCN2022097986-appb-100003
    为充电结束时刻一阶内阻值，
    Figure PCTCN2022097986-appb-100004
    为充电开始前一时刻电压，
    Figure PCTCN2022097986-appb-100005
    为充电开始时刻电压，
    Figure PCTCN2022097986-appb-100006
    为充电结束时刻电压，
    Figure PCTCN2022097986-appb-100007
    为充电结束后一时刻电压，t charge_start-1为充电开始前一时刻，t charge_start为充电开始时刻，t charge_end为充电结束时刻，t drive_start+1为充电结束后一时刻，I为充电电流。
  6. 根据权利要求2所述的电池容量特征提取方法，其特征在于，通过以下步骤获得所述驾驶过程的一阶内阻表：
    计算在不同第二初始荷电状态、放电电流、循环次数、驾驶静态电压下的驾驶过程的一阶内阻值，其中，所述驾驶静态电压为停止驾驶或者驾 驶前静置状态下的电压的平均值；
    建立所述驾驶过程的一阶内阻值及与其对应的第二初始荷电状态、放电电流、循环次数、驾驶静态电压的第二关系表；
    基于所述总电压与荷电状态表，将所述驾驶静态电压作为总电压，获得与所述驾驶静态电压对应的第二修正荷电状态；
    将所述第二关系表中的第二初始荷电状态修改为第二修正荷电状态，获得驾驶过程的一阶内阻表。
  7. 根据权利要求1所述的电池容量特征提取方法，其特征在于，采用下述公式计算所述驾驶过程的一阶内阻值：
    Figure PCTCN2022097986-appb-100008
    Figure PCTCN2022097986-appb-100009
    其中，其中，
    Figure PCTCN2022097986-appb-100010
    为驾驶开始时刻一阶内阻值，
    Figure PCTCN2022097986-appb-100011
    为驾驶结束时刻一阶内阻值，
    Figure PCTCN2022097986-appb-100012
    为驾驶开始前一时刻电压，
    Figure PCTCN2022097986-appb-100013
    为驾驶开始时刻电压，
    Figure PCTCN2022097986-appb-100014
    为驾驶结束时刻电压，
    Figure PCTCN2022097986-appb-100015
    为驾驶结束后一时刻电压，t drive_start-1为驾驶开始前一时刻，t drive_start为驾驶开始时刻，t drive_end为驾驶结束时刻，t drive_end+1为驾驶结束后一时刻，I为放电电流。
  8. 根据权利要求1所述的电池容量特征提取方法，其特征在于，通过下述步骤获得所述充电容量衰减率：
    基于所述电池单体电压与荷电状态表和充电开始前静置状态的电池单体电压最低值，确定充电开始前静置状态的荷电状态；
    基于所述电池单体电压与荷电状态表和充电结束时静置状态的电池单体电压最高值，确定充电结束后静置状态的荷电状态；
    基于所述动力电池每个时刻的荷电状态，确定充电开始前静置状态的时刻和充电结束后静置状态的时刻；
    基于所述充电开始前静置状态的时刻和充电结束后静置状态的时刻， 计算充电容量衰减率。
  9. 根据权利要求8所述的电池容量特征提取方法，其特征在于，采用下述公式计算所述充电容量衰减率：
    Figure PCTCN2022097986-appb-100016
    其中，
    Figure PCTCN2022097986-appb-100017
    为充电开始前静置状态的时刻到充电结束后静置状态的时刻的累计容量值，SOC charge_start为充电开始前静置状态的荷电状态，SOC charge_end为充电结束后静置状态的荷电状态，
    Figure PCTCN2022097986-appb-100018
    为充电开始前静置状态的时刻，
    Figure PCTCN2022097986-appb-100019
    为充电结束时静置状态，Q now为当前电池最大可用容量，Q ini为电池初始最大可用容量，SOH c1为充电容量衰减率，i为电流。
  10. 根据权利要求8所述的电池容量特征提取方法，还包括：采用下述公式计算放电容量衰减率：
    Figure PCTCN2022097986-appb-100020
    其中，SOH c2为放电容量衰减率，M drive_end为驾驶结束里程，M drive_start为驾驶开始里程，M NEDC为里程续航。
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