JPH1014116A - Residual battery capacity indicator for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to measure the residual battery capacity accurately even when auxiliary power is stopped. SOLUTION: A residual battery capacity "indicator installed in an electric vehicle which drives auxiliary power according to pedal stepping power has an indicating section 1 which is installed in the electric vehicle and has a plurality of lamps, a residual capacity measuring section 3 which measures the battery residual capacity based on a voltage value 9a of a battery 12 of the electric vehicle, and an indication controlling section 2 which controls the lighting and flickering of the lamps according to the battery residual capacity measured by the battery residual capacity measuring section 3. The battery residual capacity measuring section 3 has a measuring means 3B which measures the residual capacity at all times during the driving of auxiliary power and a measuring means 3C which measures the residual capacity when a specified period of time has passed after the auxiliary power stops during the stoppage of the auxiliary power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining amount display device for an electric vehicle, and more particularly, measures and displays the remaining amount of a battery installed in the electric vehicle and supplying power to auxiliary power of the electric vehicle. The present invention relates to a battery level display device. Examples of the electric vehicle include an electric assist bicycle and an electric wheelchair.

[0002]

2. Description of the Related Art Conventionally, a battery remaining amount display device for an electric vehicle is provided with one remaining amount indicating lamp (red), which is turned off when the remaining amount is large, and is turned on or blinking when the remaining amount of the battery is small. And inform the driver.

[0003]

However, in the above-mentioned conventional example, the information given by one lamp is, for example, two elements, that is, more or less than a predetermined remaining amount of 5%. There was a disadvantage that it was not possible to grasp.

[0004] For this reason, although the power consumption rate changes depending on the load at the time of traveling, there is an inconvenience that it is difficult for the driver to feel the change in the power consumption that changes according to the load.

[0005] Further, in the conventional battery remaining amount measuring method,
Although the remaining battery level was measured based on the correlation between the current value, the battery voltage, and the remaining battery level, it is difficult to accurately measure the remaining battery level based on the voltage value when the auxiliary power is stopped and the current value is “0”. , There was an inconvenience.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a battery remaining amount display device for an electric vehicle which can solve the disadvantages of the prior art and can measure the battery remaining amount accurately even when the auxiliary power is stopped. That is its purpose.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a battery remaining amount display device mounted on an electric vehicle (for example, an electric assist bicycle) for driving an auxiliary power (motor) according to a pedal depression force. A display unit equipped with a plurality of lamps, a remaining amount measuring unit for measuring the remaining amount of the battery based on the voltage value of the battery (battery) of the electric vehicle, and a battery measured by the remaining amount measuring unit A display control unit that controls lighting and blinking of the lamp according to the remaining amount. Moreover, the remaining amount measuring unit measures the remaining amount of the battery while the auxiliary power is being driven, and measures the remaining battery level after a certain period of time has elapsed from the stop of the auxiliary power while the auxiliary power is stopped. And a stop-time measuring means. This aims to achieve the above-mentioned object.

In the present invention, in order to more accurately measure the remaining battery power when the auxiliary power is stopped, the measurement method is switched between when the auxiliary power is driven and when the auxiliary power is stopped. Since the remaining battery level is measured after a predetermined time (for example, 5 seconds) has elapsed since the stop of the operation, stable measurement is performed regardless of a change in the voltage value depending on whether the current value of the auxiliary power immediately before the stop is large.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a battery remaining amount display device for an electric vehicle according to the present invention. A battery remaining amount display device mounted on an electric vehicle that drives auxiliary power in accordance with a pedal depression force includes a display unit 1 provided on the electric vehicle and having a plurality of lamps, and a voltage value 9a of a battery (battery) 12 of the electric vehicle. And a display control unit 2 that controls lighting and blinking of a lamp according to the remaining battery level measured by the remaining battery level measurement unit 3.
And

In addition, the remaining amount measuring unit 3 includes a driving time measuring means 3B for constantly measuring the remaining amount while the auxiliary power is being driven, and the remaining time after the auxiliary power is stopped for a certain period of time while the auxiliary power is stopped. And a stop-time measuring means 3C for measuring the amount.

The remaining amount measuring unit 3 controls the switching between the driving-time measuring unit 3B and the stop-time measuring unit 3C depending on whether or not the auxiliary power is driven. Since the remaining battery level is measured after a lapse of time, it is possible to prevent the measurement of the remaining level when the battery voltage is unstable immediately after the motor stops, and therefore, regardless of the value of the drive current value immediately before the stop. In addition, accurate and stable measurement of the remaining battery level can be performed.

[0013] Further, the driving time measuring means 3B is provided with a first predetermined voltage corresponding to the battery voltage value and the driving current value of the auxiliary power.
A current value measuring function for measuring the remaining battery level based on the remaining battery level conversion table, and the stop-time measuring means 3C includes a second remaining capacity conversion table predetermined according to the battery voltage value and the battery temperature. It has a temperature-dependent measurement function for measuring the remaining battery level based on the temperature.

As described above, when the driving of the auxiliary power is stopped, the remaining amount of the battery is measured based on the relationship between the voltage value when the current value is set to "0" and the battery temperature. The remaining battery level can be measured.

Further, the first remaining amount conversion table has a plurality of remaining amount conversion tables corresponding to the battery temperature, and the driving time measuring means reads the first remaining amount conversion table from the first remaining amount conversion table based on the battery temperature. A conversion table selection function for selecting a remaining amount conversion table according to the temperature is provided. For this reason, it is possible to calculate the remaining battery capacity according to the battery characteristics accompanying the change in the battery temperature.

Further, the remaining amount measuring unit 3 includes a previous measurement value use unit that does not update the remaining battery amount when the remaining battery amount calculated based on the battery voltage is larger than the previously measured remaining battery amount. I have. Since the battery voltage gradually recovers when the load is removed, in such a case, the measured value will be larger than the previous battery remaining amount. Is used to avoid user confusion.

As shown in FIG. 1, the remaining amount measuring section 3 measures a current measuring module 7 for measuring a current value 7a, a voltage measuring module 9 for measuring a voltage value 9a, and a battery temperature 13a. A battery temperature measuring unit 13 is provided. These measures the operating state of the motor 11 and the battery 12 of the electric vehicle.

[0018]

Next, an embodiment in which an electric assist bicycle is adopted as an electric vehicle will be described.

FIG. 2 is a configuration diagram showing an example of the display unit 1. As shown in FIG. As shown in FIG. 2A, the display unit 1 is provided at a position where the driver of the electric assist bicycle can easily see. Further, as shown in FIG. 2B, the display unit 1 has three lamps (remaining amount indicating lamps) 1a to 1c. In this embodiment, the left two are green and the right one is red.

FIG. 3 is an explanatory diagram showing an example of the remaining battery level display on the display unit 1 shown in FIG. Display control unit 2
Controls lighting and blinking of a lamp according to the remaining battery capacity (battery capacity) as shown in FIG. In the present embodiment, when the remaining amount of the battery becomes 50% from the state of completion of the charging, the green lamps 1a and 1b are turned on and the green lamp 1 is turned on.
It changes to lighting of only b. For this reason, the driver can accurately grasp the battery power consumption according to the load during traveling by accumulating traveling experience.

FIG. 4 is a graph showing characteristics of the secondary battery. The secondary battery has a characteristic that the internal resistance of the battery increases as the remaining amount of the battery decreases. Then, the voltage drop caused by the current flowing through the battery increases. When the current value is the same, the battery voltage value decreases as the remaining battery level decreases. In addition, the battery voltage at the time of no load (with no current flowing) also decreases as the remaining amount decreases.

For this reason, in this embodiment, as shown in FIG. 5, the battery characteristics are checked in advance, and the relationship between the current and voltage at each remaining battery level is mapped and stored in the memory 3A. The figures shown are examples that emphasize the change,
Specify more in detail as needed.

FIGS. 6 and 7 are flowcharts showing an example of the remaining battery level measuring process by the configuration shown in FIG.

First, a motor speed is obtained (step S1). This is the motor rotation speed calculated by the motor controller 3 according to the pedal depression force. If the motor has stopped, the process at the time of stopping the motor is performed (step S2).

On the other hand, if the motor speed is not "0",
Clear the flag that counts 5 seconds (step S
4). The 5s-flag is a flag used in a process for prohibiting the measurement of the remaining battery level after the motor is stopped. If the motor speed is not "0", the remaining battery level measurement unit 3C does not measure the remaining battery level. , Clear this flag.

Next, the battery temperature T is measured (step S).
5). Further, a map shown in FIG. 5A is selected according to the battery temperature T (step S6). Subsequently, the current value I and the voltage value V are measured (steps S7 and S8).
Based on the current value I and the voltage value V, the remaining battery value CpNew is obtained from a map (step S9). If there is no direct value on the map, it is corrected from the values before and after.

Next, the previously measured remaining battery value Cp
Pre is compared with the remaining battery value CpNew measured this time (step S10). This is a process for preventing the driver from being confused by not updating the display when the remaining battery level is recovered (increased). When the battery remaining value CpPre measured last time is larger than the battery remaining value CpNew measured this time, the battery remaining value measured last time is set as the battery remaining value measured this time (step S11).

Further, according to a predetermined remaining amount display,
Select a battery display pattern (steps S16-
S18). Alternatively, the battery may be prevented from being discharged by displaying a value smaller than the value measured by the remaining amount measuring unit 3. For example, when the remaining battery capacity reaches 60% or more in step S12, the remaining battery capacity may be displayed as 50% in step S15.

FIG. 7 is a flowchart showing the processing when the motor is stopped. When the motor is stopped,
The motor is not driven again for a certain period of time (here,
After 5 seconds), the remaining battery level is measured. For this reason, a flag (5s
-Flag). Also, 5s counter Cnt
Is a count value for counting 5 seconds.

First, when the flag is "0", the value of the flag is set to "1" and the value of Cnt is set to "0" (step S22). Thereby, the count of 5 seconds is started. Next, the parallel processing for incrementing Cnt every second is started. Specifically, a timer is started. This value of Cnt is used in step S24.

After the start of the counting, the flow returns to step S1 to check whether the motor is rotating. If the state where the motor is stopped continues, the value of Cnt becomes “5” in step S25. Then, since the battery voltage value is stable enough to enable stable measurement of the remaining battery charge,
The battery temperature T is measured (step S26), and a map shown in FIG. 5B corresponding to the battery temperature T is selected.

Here, the current value I is measured (step S2).
8) If the current value is not “0” even though the motor is not driven (step S29), it is determined that there is some abnormality, and a predetermined abnormality handling process is performed (step S3).
0), the remaining battery level is not measured. As the abnormality handling process, for example, an abnormality notification is performed by the display unit 1.

When it is confirmed that the current value I is "0" and normal, the voltage value is measured (step S31),
Further, a corresponding remaining battery level in the map is specified from the voltage value V and the battery temperature T (step S32).

As described above, according to the present embodiment, the state of charge of the battery can be determined by the three lamps, so that a mistake in forgetting to charge, an abnormality in the battery, and a failure in the charging system can be prevented. In addition, since it becomes easy to grasp the process of decreasing the remaining amount of the battery, it is possible to estimate the total mileage. For this reason, when going back and forth along a certain route, it is easy to prevent a phenomenon that the battery runs out on the return route. In addition, by accumulating the traveling experience, it is possible to expect a driver's accurate judgment on the traveling schedule and the charging point.

Furthermore, since the measurement of the remaining battery level is switched between when the motor is driven and when the motor is stopped, maps corresponding to the battery characteristics in each state can be created. The remaining battery capacity can be specified very accurately.

[0036]

Since the present invention is constructed and functions as described above, according to this, the remaining amount measuring unit controls the switching between the driving time measuring means and the stop time measuring means depending on whether or not the auxiliary power is driven. Further, since the stop-time measuring means measures the remaining battery power after a certain period of time has elapsed since the stop of the auxiliary power, it is possible to prevent the measurement of the remaining power when the battery voltage is unstable immediately after the motor stops. Therefore, it is possible to provide an unprecedented excellent battery remaining amount display device for an electric vehicle that can accurately and stably measure the remaining battery amount regardless of the value of the drive current value immediately before the stop.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

2A and 2B are explanatory diagrams showing a configuration of a display unit shown in FIG. 1; FIG. 2A is a diagram showing a state of attachment to an electric assist bicycle, and FIG. 2B is a front view of the display unit; is there.

FIG. 3 is an explanatory diagram showing an example of a remaining battery level display by a display unit shown in FIG. 2;

FIG. 4 is a graph showing characteristics of the battery (secondary battery) shown in FIG.

FIG. 5 is an explanatory diagram illustrating an example of a remaining amount conversion table (map) used by the remaining amount measurement unit. FIG. 5A is a diagram illustrating an example of a first remaining amount conversion table. B) is a diagram showing an example of a second remaining amount conversion table.

6 is a flowchart illustrating an example of a remaining amount measurement process by a remaining amount measuring unit illustrated in FIG. 1, and particularly illustrating an operation example of a driving-time measuring unit.

FIG. 7 is a flowchart illustrating an example of a remaining amount measurement process connected to FIG. 6, and particularly illustrating an operation example of a stop time measurement unit.

[Explanation of symbols]

 Reference Signs List 1 display unit 2 display control unit 3 remaining amount measuring unit 3A memory (for storing remaining amount conversion table) 3B driving measuring unit 3C stopping measuring unit 5 motor controller 7 current measuring module 9 voltage measuring module 11 motor 12 battery 13 battery temperature Measuring unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B62M 23/02 B62M 23/02 H G01R 31/36 G01R 31/36 E // H01M 10/48 H01M 10/48 P

Claims (4)

[Claims] 1. A battery remaining amount display device mounted on an electric vehicle that drives auxiliary power in accordance with a pedal depressing force, a display unit provided on the electric vehicle and having a plurality of lamps, and a voltage of a battery of the electric vehicle. A remaining amount measuring unit that measures the remaining amount of the battery based on the value, and a display control unit that controls lighting and blinking of the lamp according to the remaining amount of the battery measured by the remaining amount measuring unit, The remaining amount measuring unit measures the remaining amount of the battery while the auxiliary power is being driven, and measures the remaining battery level after a certain time has elapsed from the stop of the auxiliary power while the auxiliary power is stopped. A battery remaining amount display device for an electric vehicle, comprising: a stop time measurement unit. 2. The method according to claim 1, wherein the driving-time measuring means measures the remaining battery power based on a first remaining power conversion table predetermined according to the battery voltage value and a driving current value of the auxiliary power. A measurement function, wherein the stop-time measuring means includes a temperature-based measurement function of measuring the battery remaining amount based on a second remaining amount conversion table predetermined according to a voltage value and a temperature of the battery. The battery remaining amount display device for an electric vehicle according to claim 1, wherein: 3. The first remaining amount conversion table includes a plurality of remaining amount conversion tables according to a battery temperature, and the driving-time measuring unit performs the first remaining amount conversion table based on the battery temperature. 3. The battery remaining amount display device for an electric vehicle according to claim 1, further comprising a conversion table selecting function for selecting a remaining amount conversion table according to the battery temperature from the table. 4. The apparatus according to claim 1, wherein the remaining amount measuring unit includes a previous measurement value use unit that does not update the remaining battery amount when the remaining battery amount calculated based on the battery voltage is larger than the previously measured remaining battery amount. The battery remaining amount display device for an electric vehicle according to claim 1, wherein: