JP2017195681A - Battery capacity measuring apparatus and battery capacity measuring program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery capacity measuring apparatus capable of achieving highly precise calculation of a battery capacity.SOLUTION: Battery capacity measuring apparatus 29, 30, 31, measuring a battery capacity of an on-vehicle battery 11 when battery charging is performed until the battery is fully charged after the battery is discharged to an empty state, includes a measurement part 2 and a control part 3. The measurement part 2 measures a remaining amount of the battery 11. The control part 3 controls operations of on-vehicle apparatuses 15-19 connected with the battery 11. The control part 3, when the remaining amount of the battery 11 reaches less than a predetermined value during discharging of the battery 11, reduces power consumption of the on-vehicle apparatuses 15-19 to maintain the power constant more than when the remaining amount of the battery is not less than the predetermined value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus and a program for measuring the battery capacity of an in-vehicle battery.

  2. Description of the Related Art Conventionally, a method using a current integration method (Coulomb counter method) is known as one of methods for measuring the battery capacity of a battery (drive battery) mounted on an electric vehicle or a hybrid vehicle. That is, the charging capacity is obtained by integrating the current values when the battery is discharged to the empty state and then charged to the fully charged state. Since the charge capacity obtained by such a method is commensurate with the capacity deterioration of the battery at that time, it is recommended to measure it as one of the maintenance inspection items (see Patent Document 1).

JP 2008-278624

  However, depending on the discharge state when discharging the battery to the empty state, there is a problem that the charge capacity cannot be accurately grasped. For example, the greater the rate of decrease in battery voltage (or the rate of increase in discharge depth), the higher the concentration of lithium ions ionized from the positive electrode into the electrolyte. As a result, the amount of lithium ions adsorbed again on the positive electrode upon completion of discharge increases, so that the amount of battery voltage swinging back increases, and the battery discharge depth becomes shallower than the intended depth (ie, 0%). As a result, the value of the charge capacity calculated from the integrated current value is evaluated to be less than the actual value. Therefore, the estimated value of the cruising distance of the vehicle is shorter than the actual value, and good estimation accuracy cannot be obtained.

  One of the objects of the present case has been invented in view of the problems as described above, and is to provide a battery capacity measuring device and a program capable of accurately calculating the battery capacity of an in-vehicle battery. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

  (1) The battery capacity measuring device disclosed herein is a battery capacity measuring device that measures the battery capacity of the battery when the vehicle-mounted battery is discharged to an empty state and then charged to a fully charged state. The device includes a control unit that controls an operating state of an in-vehicle device connected to the battery, and a measurement unit that measures a remaining battery level of the battery. The control unit reduces the power consumption of the in-vehicle device to be constant when the remaining battery level drops below a predetermined value during discharging of the battery than when the remaining battery level is equal to or higher than the predetermined value. Hold.

It is preferable that the control unit reduce the power consumption so that a discharge speed (voltage drop speed, discharge depth reduction speed) immediately before the empty state is a predetermined speed or less. The in-vehicle device includes an air conditioning hot water heater, an air conditioning compressor, a DC-DC converter, and the like.
(2) It is preferable that the said control part reduces the said power consumption by setting the drive duty ratio of the said vehicle-mounted apparatus small.
(3) It is preferable that the control unit keeps the driving duty ratio constant until the remaining battery level is reduced to less than the predetermined value and then becomes zero.

(4) It is preferable that the said control part sets the said drive duty ratio small, so that the external temperature during discharge of the said battery is low.
(5) It is preferable that the said control part reduces the said power consumption by setting the discharge current value of the said battery small.
(6) It is preferable that the said control part hold | maintains the discharge current value of the said battery constant until it becomes zero after the said battery remaining charge falls below the said predetermined value.

(7) It is preferable that the said control part sets the said discharge current value small, so that the battery temperature during discharge of the said battery is low. Instead of or in addition to the battery temperature, the discharge current value may be set with reference to the outside air temperature or hot water temperature.
(8) It is preferable to provide a calculation unit that calculates a charge capacity of the battery based on an integrated current value when the battery is charged from an empty state to a fully charged state. In this case, the calculation unit calculates the battery health based on the charge capacity and the new battery charge capacity, and calculates the battery discharge capacity based on the charge capacity and the health. It is preferable.

  (9) The battery capacity measurement program disclosed here is a battery capacity measurement program for measuring the battery capacity of the battery when the vehicle-mounted battery is discharged to an empty state and then charged to a fully charged state. This program is a program for causing a computer to function as a control unit that controls an operating state of an in-vehicle device connected to the battery and a measurement unit that measures the remaining battery level of the battery. Further, the control means reduces the power consumption of the in-vehicle device when the remaining battery level drops below a predetermined value during discharging of the battery than when the remaining battery level is equal to or higher than the predetermined value. Has a function to keep it constant.

  By reducing the power consumption of the in-vehicle device and keeping it constant immediately before the in-vehicle battery becomes empty, the fluctuation can be suppressed while reducing the amount of battery voltage to swing back. Therefore, the calculation accuracy of the battery capacity measured at the time of subsequent charging can be improved.

It is a figure for demonstrating the vehicle carrying the battery of a measuring object. It is a block diagram for demonstrating the structure of a battery capacity measuring apparatus. (A) is a graph illustrating the voltage change during charging and discharging, and (B) to (D) are graphs for explaining the amount of battery voltage to swing back. (A) is a graph illustrating the relationship between the outside air temperature and the drive duty ratio, (B) is a graph illustrating the relationship between the battery temperature and the discharge current value, and (C) illustrates the relationship between the soundness level and the conversion coefficient. It is a graph to do. It is a flowchart which illustrates the procedure in the case of controlling a drive duty ratio. It is a flowchart which illustrates the procedure in the case of controlling a discharge current value.

  A battery capacity measuring apparatus as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined.

[1. Vehicle configuration]
A secondary battery that is a target of “measurement control” for measuring battery capacity (discharge capacity, charge capacity) in the present embodiment is a battery 11 (drive battery) mounted on a vehicle 10 as shown in FIG. . The vehicle 10 is an electric vehicle equipped with at least a traveling motor generator 12 (simply referred to as a motor 12). Alternatively, it is a hybrid vehicle equipped with an engine 14 for driving not only the motor 12 but also a motor generator 13 for power generation (simply called the generator 13). The engine 14 is a prime mover that drives the generator 13 to generate electric power, and is controlled so as to continue operation in a rotational speed region where engine efficiency is high as necessary.

  The battery capacity of the battery 11 is measured during external charging by an external power supply facility. An inlet 25 (charging port) for connecting the vehicle 10 to an external power supply facility is provided on the side surface of the vehicle 10. The inlet 25 is provided with a normal charging socket that can be connected to a household outlet 27 using a charging cable 26 and a quick charging socket that can be connected to a charging stand 28. In the present embodiment, the control for measuring the battery capacity of the battery 11 during normal charging via the normal charging socket will be described in detail, but it is also possible to measure the battery capacity during quick charging via the quick charging socket. . In principle, it is also possible to measure the battery capacity during charging using the electric power generated by driving the generator 13 with the engine 14 (during internal charging).

  As shown in FIG. 2, the motor 12 (generator 13) is connected to the battery 11 via the inverter 15. Hereinafter, the DC circuit connected to the battery 11 is referred to as a battery circuit 20. The battery circuit 20 is provided with a contactor (circuit connection / disconnection switch) (not shown), and the charge / discharge current of the battery 11 is supplied and disconnected according to the connection / disconnection state of the contactor.

  A control circuit 41 and an assembled battery 42 are built in the battery 11. The assembled battery 42 is a secondary battery serving as a power supply source of the motor 12, and is, for example, a lithium ion secondary battery, a lithium ion capacitor, a nickel hydrogen storage battery, an alkaline ion storage battery, or the like. The control circuit 41 is an electric circuit in which a switching element (for example, a bipolar transistor or FET) or a variable resistor is interposed, and has a function of controlling at least the discharge current of the battery 11.

  The inverter 15 is a converter (DC-AC inverter) that mutually converts DC power on the battery 11 side and AC power on the motor 12 side. When the motor 12 is powered, alternating drive power is supplied from the battery 11 side to the motor 12 side. On the other hand, during the regeneration of the motor 12 or the power generation of the generator 13, DC charging power is supplied from the motor 12 side to the battery 11 side. The inverter 15 and the motor 12 (generator 13) are connected by a three-phase AC power line. Note that the circuit closer to the motor 12 than the inverter 15 can be boosted to about 600 [V], for example. On the other hand, the voltage of the battery circuit 20 is about 200 to 300 [V].

Connected to the battery circuit 20 are in-vehicle devices such as a transformer 16, a charger 17, an air conditioning compressor 18, and an air conditioning hot water heater 19. The transformer 16 is a DC-DC converter for supplying the electric power of the battery 11 to a low voltage system (so-called 12 [V] system), and automatically when the storage amount of the auxiliary battery 24 falls below a predetermined amount. And has a function of charging the auxiliary battery 24.
The charger 17 is an on-board charger (OBC) that charges the battery 11 by converting power input from an external power supply facility during normal charging. Here, AC power supplied from the outside of the vehicle 10 is converted into DC power having a predetermined charging voltage corresponding to the battery voltage, and the battery 11 is charged.

  The air-conditioning compressor 18 is a compressor for pumping refrigerant used during cooling of the air-conditioning apparatus, and the air-conditioning hot water heater 19 is a heater for raising the temperature of hot water used during heating. These are used as an electric load when the battery 11 is discharged to an empty state immediately before performing normal charging. Further, a controller 32 (modulator) and a heater 33 are provided inside the hot water heater 19 for air conditioning.

  The controller 32 converts the direct current supplied from the battery 11 into a pulse signal and outputs it to the heater 33. Here, for example, the pulse width of a pulse signal modulated by a PWM (Pulse Width Modulation) method is adjusted, and the magnitude of the current (power) output to the heater 33 is freely controlled. The value of the duty ratio (drive duty ratio) of the pulse signal output from the controller 32 can be changed. The heater 33 is a heating device for raising the temperature of hot water as a heat medium. The heat given by the heater 33 is transferred to the air through the heat exchanger and supplied into the vehicle interior by the hot air fan.

  The battery 11 is provided with a current sensor 21, a voltage sensor 22, and a battery temperature sensor 23 as sensors for acquiring parameters corresponding to the charge / discharge state. The current sensor 21 detects the current (input / output current) of the battery 11, the voltage sensor 22 detects the voltage of the battery 11, and the battery temperature sensor 23 detects the battery temperature. Various types of information detected by these sensors 21 to 23 are transmitted to the battery control device 29 that controls the operating state and charging / discharging state of the battery 11.

  The battery control device 29 measures, calculates, and controls the charge / discharge state of the battery 11, the charge rate SOC (State Of Charge), the soundness level SOH (State Of Health), the operating state of the control circuit 41, the state of the assembled battery 42, and the like. This is an electronic control device (computer, ECU, Electronic Control Unit) having the function of connecting to the in-vehicle network of the vehicle 10. The battery control device 29 includes a processor, a memory, an interface device, and the like that are connected to each other via a bus.

  The processor is a processing device including, for example, a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (register), and the like. The memory is a storage device that stores a program and working data, and includes a ROM (Read Only Memory), a RAM (Random Access Memory), a nonvolatile memory, and the like. The contents of the control performed by the battery control device 29 are recorded and stored in the memory as firmware or an application program. When the program is executed, the contents of the program are expanded in the memory space and executed by the processor.

  In addition to the sensors 21 to 23 described above, the motor 12, the generator 13, the engine 14, the inverter 15, the transformer 16, the charger 16, the air conditioning compressor 18, the air conditioning hot water heater 19, and the like are connected on the in-vehicle network. . Also, it is possible to connect any electronic device to the in-vehicle network via a connector (not shown).

  In FIG. 2, a measurement device 30 (MUT, Multi-Use Tester) for extracting the measurement results of the operating state and the charge / discharge state of the battery 11 and the measurement results of the measurement device 30 are analyzed and displayed. The vehicle 10 connected with the notebook personal computer 31 is illustrated. Both the measuring device 30 and the notebook personal computer 31 are electronic devices (computers) including a processor, a memory, and an interface device connected to each other via a bus. The drive currents of the battery control device 29 and the measurement device 30 are supplied from the low voltage system of the vehicle 10.

[2. Control configuration]
The main body of measurement control for measuring the battery capacity of the battery 11 during external charging includes at least one of the battery control device 29, the measurement device 30, and the notebook computer 31. The measurement control program 1 (measurement program) is recorded and stored in, for example, a memory built in the battery control device 29, the measurement device 30, or the notebook personal computer 31, or recorded on a recording medium readable by these computers. Saved.

In the measurement control, as shown in FIG. 3A, control is performed in which the battery 11 is discharged to a full state after being discharged to an empty state. The term empty state of the battery 11 corresponds to the state at time t ₁ and the voltage of the battery 11 is in a state where a predetermined lower limit voltage (discharge termination voltage, for example, 2.5 [V]). Similarly, the fully charged state equivalent to the state of time t _2, the voltage of the battery 11 is in a state where a predetermined upper limit voltage (charge voltage, for example, 4.2 [V]). Charge capacity of the battery 11 is calculated by integrating the current value from time t ₁ to time t _2.

As a load for discharging the battery 11, an air conditioning compressor 18 and an air conditioning warm water heater 19 are used (or used in combination). Further, in the discharge is completed the time t _1, unwag amount R of the battery voltage is changed according to the discharge state. For example, when the battery voltage decrease rate is small, the amount of swingback R is a relatively small value as shown in FIG. On the other hand, when the rate of decrease of the battery voltage is large, as shown in FIG. 3 (C), the amount of swingback R becomes a relatively large value. Such fluctuations in the amount of swingback R are one of the factors that reduce the calculation accuracy of the charge capacity. In addition, the larger the swingback amount R, the smaller the evaluation result of the charge capacity is evaluated.

Therefore, in the measurement control according to the present embodiment, control is performed to keep the output of the battery 11 (that is, the power consumption of the in-vehicle device) at a constant level while the discharge is finished, while keeping it constant. For example, as shown in FIG. 3D, the battery voltage decrease rate (voltage decrease rate, discharge depth decrease rate) between time t ₀ before the completion of discharge and time t _{1 at} which discharge is completed. There discharge state is controlled to be smaller predetermined speed less than the time t ₀ before. In other words, the discharge state is controlled so that the decrease gradient ΔV of the battery voltage becomes a small and constant value just before the end of the discharge. As a result, the amount of swingback R is reduced, fluctuations in the amount of swingback R are suppressed, and the calculation accuracy of the charge capacity is improved.

  The measurement program 1 (battery capacity measurement program) includes a measurement unit 2 (measurement unit), a control unit 3 (control unit), and a calculation unit 4 (calculation unit). These represent the functions of measurement control programmed as software. These functions can be realized by causing the processors of the battery control device 29, the measurement device 30, and the notebook personal computer 31 to read the measurement program 1 and execute arithmetic processing. However, these functions can also be realized by an electronic circuit (hardware). Alternatively, a part of these functions may be hardware, and the other part may be software.

  The measuring unit 2 has a function of measuring the remaining battery level of the battery 11. The remaining battery level can be calculated by integrating the charge / discharge current detected by the current sensor 21. Alternatively, the relationship between the voltage of the battery 11 and the remaining battery level may be grasped in advance in the form of a map, a graph, a mathematical expression, or the like, and the remaining battery level corresponding to the voltage detected by the voltage sensor 22 may be calculated. Information on the remaining battery level calculated here is transmitted to the control unit 3.

  The control unit 3 has a function of controlling the charge / discharge state of the battery 11 and the operating state of the in-vehicle device connected to the battery 11. The on-vehicle device here includes an inverter 15, a transformer 16, a charger 17, an air conditioning compressor 18, an air conditioning hot water heater 19, and the like. In the present embodiment, details of control when the air-conditioning hot water heater 19 is a control target will be described in detail.

  When the remaining battery level drops below a predetermined value (for example, less than the equivalent of one segment) in the discharge state of the battery 11 shown in FIG. In contrast, control is performed to reduce the power consumption of the air-conditioning hot water heater 19 and keep it constant. In other words, the operating state of the air-conditioning hot water heater 19 is controlled so that the rate of voltage drop immediately before the discharge of the battery 11 is completed (immediately before the battery 11 becomes empty). Thereafter, after confirming that the battery 11 is empty, the battery 11 is charged to a fully charged state.

  The “segment” is a minimum unit of the battery remaining amount displayed on the battery fuel gauge (power meter) provided in the vehicle interior of the vehicle 10. For example, 16 battery segments arranged in a bar graph are displayed on the battery level indicator as a fully charged battery level. Further, as the remaining battery level decreases from the fully charged state, the number of segments to be lit is reduced, and when the remaining battery level becomes zero, all segments are turned off. Therefore, the “one-segment equivalent amount” here is a minute value close to zero, and is a battery remaining amount of about several percent in terms of the charge rate SOC. Instead of confirming that the remaining battery level has decreased below a predetermined value, it may be confirmed that the battery voltage has decreased below a predetermined voltage (for example, 3.0 [V]).

There are the following three types of methods for reducing the power consumption just before the discharge is completed.
The first method is to reduce the drive duty ratio of the hot water heater 19 for air conditioning. That is, by reducing the pulse width of the pulse signal output from the controller 32 to the heater 33, the power consumption of the air-conditioning hot water heater 19 is reduced. In this case, the control unit 3 keeps the value of the drive duty ratio constant until the remaining battery level during discharge becomes zero (that is, empty). Note that the value of the drive duty ratio may be a preset fixed value (for example, about several percent) or a variable value set according to the outside air temperature. For example, as shown in FIG. 4A, the relationship between the drive duty ratio and the outside air temperature may be such that the drive duty ratio becomes smaller as the outside air temperature is lower. Thereby, the output according to the fluctuation | variation of the internal resistance value of the battery 11 will be set, and the fall rate of a battery voltage will become fixed. For example, even if the internal resistance value of the battery 11 increases due to a decrease in the outside air temperature, an increase in the battery voltage decrease gradient ΔV can be prevented by reducing the drive duty ratio.

  The second method is to reduce the discharge current value of the battery 11. That is, by reducing the current supplied to the battery circuit 20 by the control circuit 41, the power consumption of the air conditioning hot water heater 19 is reduced. In this case, the control unit 3 keeps the discharge current value constant until the remaining battery level during discharge becomes zero. The discharge current value may be a preset fixed value (for example, about several amperes) or a variable value set according to the battery temperature. For example, as shown in FIG. 4B, the relationship between the discharge current value and the battery temperature may be such that the lower the battery temperature, the smaller the relationship. Thereby, the output according to the fluctuation | variation of the internal resistance value of the battery 11 will be set, and the fall rate of a battery voltage will become fixed.

  The third method uses both the first method and the second method. That is, both the drive duty ratio of the air-conditioning hot water heater 19 and the discharge current value of the battery 11 are reduced. In this case, the control unit 3 keeps both the drive duty ratio and the discharge current value constant until the remaining battery level during discharge becomes zero. Thereby, while the power consumption of the warm water heater 19 for air conditioning further reduces, the fluctuation | variation is suppressed. In addition, while using both the first method and the second method, control may be added such that one method is stopped according to the outside air temperature or the battery temperature and only the other method is selected.

  The calculation unit 4 has a function of calculating the charge capacity and discharge capacity of the battery 11 and a function of outputting and storing the calculation result. The charge capacity is calculated as an integrated current value when the battery 11 is charged from an empty state to a fully charged state. Further, the discharge capacity is calculated based on the soundness level SOH of the battery 11 and the charge capacity. Preferably, the discharge capacity is calculated based on a value obtained by multiplying the charge capacity by the conversion coefficient. The conversion coefficient is a coefficient representing the ratio of the discharge capacity to the charge capacity, and is set according to the soundness level SOH of the battery 11. The soundness level SOH here is expressed as a percentage of the current charging capacity with respect to the charging capacity when the battery 11 is new.

  The value of the conversion coefficient is set to a smaller value as the soundness level SOH is lower (deterioration is progressing, the soundness level SOH is closer to 0%). FIG. 4C is a graph illustrating the relationship between the soundness level SOH and the conversion coefficient. In this example, a characteristic is set such that the value of the conversion coefficient gradually approaches 1.0 as the soundness degree SOH approaches 100%. The calculation unit 4 sets a conversion coefficient based on the characteristics defined in such graphs and maps, and uses this to calculate the discharge capacity.

  Information on the charge capacity and discharge capacity calculated by the calculation unit 4 is recorded and stored as a parameter representing the actual charge / discharge capacity of the battery 11 at that time. When the main body that performs the measurement control is the battery control device 29, the measurement result is recorded and stored in a nonvolatile memory in the battery control device 29, and is used for the subsequent calculation of the charge rate SOC and the soundness level SOH. On the other hand, when the main body that performs the measurement control is the measurement device 30 or the notebook computer 31, the measurement result is displayed on the display and output to the battery control device 29, and the information is stored in the nonvolatile memory in the battery control device 29. Is recorded and saved.

  In addition, the value of the charging rate SOC of the battery 11 is calculated as a percentage of the remaining battery level at that time with respect to the charging capacity (or discharging capacity). The remaining battery level is calculated by subtracting the power consumption from the above charge capacity (or discharge capacity) as needed. Further, the cruising distance of the vehicle 10 is calculated by multiplying the remaining battery level at that time by the power consumption (the average value of the distance traveled by the vehicle in unit power amount). Therefore, by improving the calculation accuracy of the charge capacity and the discharge capacity, the estimation accuracy of the charging rate SOC, the soundness level SOH, the cruising range, and the like are also improved.

[3. flowchart]
FIG. 5 is a flowchart illustrating a specific execution procedure of measurement control. In this flow, power consumption is reduced by reducing the drive duty ratio of the hot water heater 19 for air conditioning just before the completion of discharging before charging. First, when it is detected and confirmed that the charging cable 26 is connected between the vehicle 10 and the outlet 27 and the measuring device 30 is connected to the battery control device 29 (step A1), the battery control device 29, The measurement program 1 is executed in either the measurement device 30 or the notebook personal computer 31, and measurement control is started. In the measurement control, the operating state of the air conditioning hot water heater 19 is controlled so that the battery 11 is temporarily emptied before starting external charging.

  That is, discharging from the battery 11 is started, and the hot water heater 19 for air conditioning is driven at almost maximum output by the power of the battery 11 (step A2). At this time, the drive duty ratio of the hot water heater 19 for air conditioning is controlled to be 90 to 100%, for example. In addition, information such as current, voltage, and battery temperature during discharge is acquired, and based on these information, it is determined whether or not the remaining battery level of the battery 11 has become less than one segment (step A3).

  When the remaining battery level of the battery 11 is less than the equivalent of one segment, the control unit 3 changes the driving duty ratio of the air conditioning hot water heater 19 to a small value (step A4), and the air conditioning hot water heater 19 is driven at a low output. (Step A5). The hot water heater 19 for air conditioning is controlled with a drive duty ratio smaller than at least step A2. Further, the value of the drive duty ratio is kept constant until the battery 11 becomes empty (step A6). As described above, by reducing the power consumption of the air-conditioning hot water heater 19 while it is about to be discharged immediately before charging, the battery voltage decrease rate becomes small and becomes a constant value. As a result, the amount of rocking R is reduced, and fluctuations thereof are suppressed.

  Thereafter, when the remaining battery level becomes zero and the battery 11 becomes empty, external charging of the battery 11 is started (step A7). During charging, information such as current, voltage, and battery temperature is acquired (step A8), and it is determined based on these information whether the battery 11 is fully charged (step A9). When the battery 11 is fully charged, the charge capacity corresponding to the time integral value of the current during charging is calculated, and the discharge capacity is calculated based on the charge capacity (step A10).

  Since the battery voltage swingback amount R is small and becomes a stable value by the control of step A5, the calculation accuracy of the charge capacity and discharge capacity is improved, and the capacity value very close to the actual charge capacity and discharge capacity is obtained. It is grasped with high accuracy. Thereafter, the measurement results (charge capacity, discharge capacity) are displayed on the display of the measurement device 30 or the notebook personal computer 31, and recorded and stored in the nonvolatile memory in the battery control device 29 (step A11), and the measurement control ends. .

  The flowchart shown in FIG. 6 implements control for reducing the discharge current value of the battery 11 just before the completion of discharging before charging, and only the step A4 in FIG. 5 is changed. By setting the discharge current value to a small and constant value (step B4), the power consumption of the air-conditioning hot water heater 19 becomes a small and constant value, and the rate of decrease in the battery voltage also becomes a small and constant value. As a result, the amount of rocking R is reduced, and fluctuations thereof are suppressed. Therefore, the calculation accuracy of the charge capacity and discharge capacity is improved, and the capacity value very close to the actual charge capacity and discharge capacity can be grasped with high accuracy.

[4. effect]
(1) In the measurement control implemented by the measurement program 1 described above, the power consumption of the hot water heater 19 for air conditioning is reduced and kept constant immediately before the on-vehicle battery 11 becomes empty. By such control, as shown in FIG. 3D, it is possible to keep the fluctuation R of the battery voltage constant while suppressing the fluctuation R of the battery voltage. Therefore, the calculation accuracy of the battery capacity measured at the time of subsequent charging can be improved. Further, by reducing the power consumption of the air-conditioning hot water heater 19, it is possible to suppress excessive temperature rise and evaporation of the hot water, and to prevent the air-conditioning hot water heater 19 from being damaged. Further, since the air-conditioning hot water heater 19 is driven at a high output until immediately before the battery 11 becomes empty, the time required to discharge the battery 11 to the empty state is not unnecessarily prolonged. Therefore, measurement control can be completed efficiently in a relatively short time.

  (2) When a method (first method) for reducing the drive duty ratio of the air-conditioning hot water heater 19 is adopted as a method for reducing the power consumption, the air-conditioning hot water heater 19 becomes a control target. Thus, there is no need to positively change the discharge state of the battery 11, and there is an advantage that it can be easily mounted. Even if the battery 11 is not equipped with a function for changing the discharge current value, the power consumption of the air-conditioning hot water heater 19 can be reduced.

(3) Since the value of the drive duty ratio is held until the battery 11 becomes empty after the remaining battery level becomes less than the predetermined value, the voltage reduction rate until the battery voltage reaches the lower limit voltage is stabilized. Can do. For example, as shown in FIG. 3D, the decrease gradient ΔV of the battery voltage can be made constant. Therefore, the calculation accuracy of the charge capacity can be improved, and the calculation accuracy of the discharge capacity can also be improved.
(4) Also, as shown in FIG. 4A, by increasing the drive duty ratio as the outside air temperature is lower, it is possible to prevent an increase in the decrease gradient ΔV due to an increase in the internal resistance value of the battery 11. The decrease gradient ΔV can be made constant. Therefore, the calculation accuracy of the charge capacity and discharge capacity can be improved.

  (5) When a technique (second technique) for reducing the discharge current value of the battery 11 is adopted as a technique for reducing the power consumption, the battery 11 becomes a control target, and thus the hot water heater 19 for air conditioning. This eliminates the need to positively change the operating state of the device, and provides an advantage that it can be easily mounted. Further, even if the air conditioning hot water heater 19 is not equipped with a function for changing the drive duty ratio, the power consumption of the air conditioning hot water heater 19 can be reduced.

(6) Since the value of the discharge current value is held until the battery 11 becomes empty after the remaining battery level becomes less than the predetermined value, the voltage drop rate until the battery voltage reaches the lower limit voltage is stabilized. Can do. For example, as shown in FIG. 3D, the decrease gradient ΔV of the battery voltage can be made constant. Therefore, the calculation accuracy of the charge capacity can be improved, and the calculation accuracy of the discharge capacity can also be improved.
(7) Further, as shown in FIG. 4B, the discharge current value is set to be smaller as the battery temperature is lower, so that the increase in the decrease gradient ΔV due to the increase in the internal resistance value of the battery 11 can be prevented. The decrease gradient ΔV can be made constant. Therefore, the calculation accuracy of the charge capacity and discharge capacity can be improved.

  (8) In the above measurement control, the discharge capacity is calculated based on the soundness level SOH of the battery 11 and the charge capacity. For example, as shown in FIG. 4C, a lower conversion coefficient is set as the soundness level SOH of the battery 11 is lower, and it is estimated that the smaller the conversion coefficient, the smaller the ratio of the discharge capacity to the charge capacity. . In this way, by referring to the charge capacity and the soundness level SOH corresponding to the discharge state before charging, the difference between the charge capacity and the discharge capacity that changes due to the deterioration of the battery 11 can be corrected, and the discharge capacity can be corrected. Calculation accuracy can be improved.

[5. Modified example]
The above measurement control can be performed not only when charging by the external power supply facility of the vehicle 10 but also when charging using the generated power generated by the generator 13. If the vehicle 10 is capable of performing at least the control of charging the vehicle-mounted battery 11 to an empty state and then charging it to a fully charged state, the above-described measurement control can be performed, and the effects derived from the above-described measurement control , Will be effective.

  In the above-described measurement control, the control for consuming the remaining power when charging the battery 11 with the hot water heater 19 for air conditioning has been described, but instead of or in addition to the hot water heater 19 for air conditioning, the compressor 18 for air conditioning and the transformer A vehicle-mounted device such as 16 may be used. As long as the vehicle-mounted device that can adjust at least the power consumption and that is interposed in the battery circuit 20 can be used, it is possible to perform control that provides the same effect as the above-described embodiment.

  In the above-described embodiment, the method of setting the drive duty ratio according to the outside air temperature has been described. However, instead of or in addition to the outside air temperature, the battery temperature or the outside air pressure, the humidity in the case of the battery 11, and the individual cell temperature. The drive duty ratio may be set using parameters such as the cumulative usage time of the battery 11 and the number of charge / discharge cycles. The same applies to the setting of the discharge current value. By using these parameters, it becomes possible to measure the battery capacity according to the environmental conditions during charging / discharging of the vehicle 10 and the usage history of the battery 11, and the calculation accuracy of the battery capacity can be further improved.

  In the above-described embodiment, the controller 32 that modulates the current supplied to the heater 33 by the PWM method is illustrated, but the modulation method is not limited to this. For example, a controller that controls current by a PAM (Pulse Amplitude Modulation) method or a PPM (Pulse Position Modulation) method may be used. Any controller, electronic circuit, or semiconductor device can be applied as long as it controls at least the drive duty ratio of the heater 33.

1 Measurement program (battery capacity measurement program)
2 Measuring unit (measuring means)
3 Control unit (control means)
4. Calculation unit (calculation means)
10 Vehicle 11 Battery (drive battery)
15 Inverter 16 Transformer (DC-DC converter)
17 Battery charger (OBC)
18 Air-conditioning compressor 19 Air-conditioning hot water heater 29 Battery control device 30 Measuring device (MUT)
31 Notebook PC 32 Controller 33 Heater 41 Control Circuit 42 Battery

Claims (9)

In the battery capacity measuring device that measures the battery capacity of the battery when charging the vehicle-mounted battery to the full state after discharging it to the empty state,
A control unit for controlling the operating state of the in-vehicle device connected to the battery;
A measuring unit for measuring the battery remaining amount of the battery,
The control unit reduces the power consumption of the in-vehicle device to be constant when the remaining battery level drops below a predetermined value during discharging of the battery than when the remaining battery level is equal to or higher than the predetermined value. A battery capacity measuring device characterized by holding. The battery capacity measuring device according to claim 1, wherein the control unit reduces the power consumption by setting a drive duty ratio of the in-vehicle device to be small. The battery capacity measuring device according to claim 2, wherein the control unit holds the driving duty ratio constant until the remaining battery level is reduced to less than the predetermined value and then becomes zero. 4. The battery capacity measuring device according to claim 2, wherein the controller sets the drive duty ratio to be smaller as the outside air temperature during discharge of the battery is lower. The said control part reduces the said power consumption by setting the discharge current value of the said battery small, The battery capacity measuring apparatus of any one of Claims 1-4 characterized by the above-mentioned. The battery capacity measuring device according to claim 5, wherein the control unit maintains a constant discharge current value of the battery until the remaining battery level becomes less than the predetermined value and then becomes zero. . The battery capacity measuring device according to claim 5 or 6, wherein the controller sets the discharge current value to be smaller as the battery temperature during discharging of the battery is lower. Based on a current integrated value when the battery is charged from an empty state to a fully charged state, a calculation unit that calculates a charging capacity of the battery,
The calculation unit calculates the battery health based on the charge capacity and the new battery charge capacity, and calculates the battery discharge capacity based on the charge capacity and the health. The battery capacity measuring device according to any one of claims 1 to 6. In the battery capacity measurement program for measuring the battery capacity of the battery when charging the vehicle-mounted battery to the full state after discharging it to the empty state,
Control means for controlling the operating state of the in-vehicle device connected to the battery;
A program for causing a computer to function as measurement means for measuring the remaining battery capacity of the battery,
The control means reduces the power consumption of the in-vehicle device to be constant when the remaining battery level drops below a predetermined value during discharging of the battery, compared to when the remaining battery level is equal to or higher than the predetermined value. A battery capacity measurement program characterized by holding.

Images