JP2016014588A - Battery management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery management device capable of quickly detecting a battery state.SOLUTION: A battery management device comprises: a current sensor 3 detecting a current of a battery 1; a voltage sensor 2 detecting a voltage of the battery 1; arithmetic means 10 computing an SCO of the battery and a full charge capacity of the battery 1 on the basis of a detection value of the current sensor 3 or the voltage sensor 2; and storage means 10 storing a first map indicating a relative relation between a variation in voltage (dV/dSOC) per unit SOC of the battery 1 and the SOC, the arithmetic means 10 computing a variation in an integrated value of the detected current (dQ/dV) per unit voltage of the battery 1 on the basis of the detected current by the current sensor 3 and the detected voltage by the voltage sensor 2, identifying the SOC corresponding to the variation (dQ/dV) as a specific SOC, computing a variation (dV/dSOC) corresponding to the specific SOC while referring to a first map, and computes a full charge capacity on the basis of the variation (dV/dSOC) corresponding to the specific SOC and the variation (dQ/dV).

Description

  The present invention relates to a battery management device.

  In a secondary battery system including a secondary battery, a value of dQ / dV, which is a ratio of a change amount dV of the battery voltage V of the secondary battery to a change amount dQ of the storage amount Q of the secondary battery, is calculated for a predetermined time Based on the value of dQ / dV calculated for each T, a Q-dQ / dV curve representing the relationship between the value of stored energy Q and dQ / dV is drawn, and this Q-dQ / dV curve is stored in the ROM. Whether or not the secondary battery is in a state corresponding to one of the characteristic points of the Q-dQ / dV curve is determined by comparison with the Q-dQ / dV curve. When it is determined that the state corresponding to the feature point has been reached, the difference value is obtained by subtracting the storage amount estimated by the battery controller when the feature point is reached from the feature reference value (storage amount) at the feature point. What calculates and correct | amends the electrical storage amount with the said difference value is disclosed (patent document 1).

JP 2010-257984 A

  However, in the above secondary battery system, since the state of the secondary battery cannot be grasped unless the state (dQ / dV) of the secondary battery becomes the characteristic point (dQ / dV), for example, the secondary battery When the secondary battery is used for a long time within the range where the state does not correspond to the feature point, there is a problem that the state of the secondary battery cannot be detected for a long time.

  The problem to be solved by the present invention is to provide a battery management device capable of detecting the state of a battery in a short time.

  The present invention stores a relative relationship between a change amount (dV / dSOC) of the battery voltage per unit SOC of the battery and the SOC in a map, and based on the detection current of the current sensor and the detection voltage of the voltage sensor, The change amount (dQ / dV) of the integrated value of the detected current per unit voltage is calculated, the SOC corresponding to the change amount (dQ / dV) is specified as the specific SOC based on the SOC, and the specific SOC is referred to while referring to the map The corresponding change amount (dV / dSOC) is calculated, and the full charge capacity of the battery is calculated based on the specified change amount (dV / dSOC) and change amount (dQ / dV), thereby solving the above problem. To do.

  In the present invention, when the SOC is specified, the full charge capacity of the battery can be calculated from the change amount (dQ / dV) and the change amount (dV / dSOC) corresponding to the specified SOC. It is possible to widen the SOC range. As a result, the state of the battery can be detected in a short time.

1 is a block diagram of a vehicle drive system according to an embodiment of the present invention. It is a block diagram of the 1st controller of FIG. FIG. 2 is a graph showing characteristics of the battery of FIG. 1 and showing characteristics of internal resistance with respect to SOC. FIG. FIG. 2 is a graph showing the characteristics of the battery of FIG. 1 and showing the characteristics of the variation (dQ / dV) with respect to the SOC. FIG. 3 is a graph showing the characteristics of the battery of FIG. 1 and showing the slope characteristics of the amount of change (dQ / dV) with respect to the SOC. FIG. 2 is a graph showing the characteristics of the battery of FIG. 1 and showing the characteristics of the variation (dV / dSOC) with respect to the SOC. It is the table | surface which showed an example of the calculation result of SOC, variation | change_quantity (dQ / dV), variation | change_quantity (dV / dSOC), and a full charge capacity. It is a flowchart which shows the control procedure of the 1st controller of FIG. It is a graph which shows the characteristic of a battery, Comprising: It is the graph which showed the characteristic of the variation | change_quantity (dQ / dV) with respect to SOC. It is a graph which shows the characteristic of a battery, Comprising: It is the graph which showed the characteristic of the variation | change_quantity (dQ / dV) with respect to SOC. It is a graph which shows the characteristic of a battery, Comprising: It is the graph which showed the characteristic of the variation | change_quantity (dV / dSOC) with respect to SOC. It is a graph which shows the characteristic of a battery, Comprising: It is the graph which showed the characteristic of the variation | change_quantity (dQ / dV) with respect to SOC.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram of a vehicle drive system including a battery management device according to the present embodiment. The battery management device of this example is a device for managing the battery of the vehicle. In the following, the embodiment will be described by taking an electric vehicle as an example of a vehicle. However, the vehicle is not limited to an electric vehicle, and may be a vehicle equipped with a battery such as a hybrid vehicle.

  The drive system includes a battery 1, a voltage sensor 2, a current sensor 3, a temperature sensor 4, a capacity adjustment unit 5, an inverter (INV) 6, a motor 7, a charger 8, and a first controller 10. The second controller 20 is provided. Among the above-described configurations included in the drive system, the voltage sensor 2, the current sensor 3, the temperature sensor 4, the capacity adjustment unit 5, and the first controller 10 correspond to the configuration of the battery management device. Note that the configuration of the battery management apparatus does not necessarily include all the above-described configurations.

  The battery 1 is a secondary battery for supplying electric power to the motor 7 and auxiliary machines. The battery 1 includes a plurality of secondary batteries (cell batteries) connected in series. Voltage sensor 2 detects the voltage of battery 1, in other words, the total voltage of a plurality of secondary batteries included in battery 1. The voltage sensor 2 is connected between the positive and negative electrodes of the battery 1.

  The current sensor 3 detects the charge / discharge current of the battery 1. The current sensor 3 is connected to the negative electrode side of the battery 1. The temperature sensor 4 detects the temperature of the battery 1. The temperature sensor 4 is provided in the vicinity of the battery 1. Detection values of the voltage sensor 2, the current sensor 3, and the temperature sensor 4 are output to the first controller 10.

  The capacity adjustment unit 5 is a circuit for adjusting variations among a plurality of secondary batteries (cell batteries) included in the battery 1. The capacity adjustment unit 5 includes a sensor for detecting the voltage of the cell battery, a resistance for capacity adjustment, and a switch for switching electrical continuity between the resistance and the secondary battery. Sensors, resistors, and switches are connected to each cell battery. The deterioration rate of the secondary battery may vary from battery to battery due to variations in individual battery characteristics. Therefore, the capacity between the cell batteries varies. The capacity adjustment unit 5 detects the voltage of each cell battery using a sensor under the control of the first controller 10 and compares the detected voltages to detect variations in each cell battery.

  For example, when the voltage of one cell battery is higher than the voltage of another cell battery by a predetermined voltage or more, the capacity adjustment unit 5 determines that the amount of variation in the capacity of the plurality of cell batteries is larger than the predetermined value. Then, it is determined that there is variation among the plurality of cell batteries. The variation amount corresponds to the voltage difference between the upper limit and the lower limit of the voltage between the cell batteries, and is a value indicating how much the capacity or voltage is different between the cell batteries. And the capacity | capacitance adjustment part 5 turns on a switch so that an electric current may conduct between one cell battery and the resistance connected to one cell battery. Thereby, since one cell battery is discharged and the capacity | capacitance of the said cell battery is adjusted, dispersion | variation is suppressed.

  The inverter 6 is a circuit for converting the power of the battery 1 into AC power and outputting it to the motor 7. The inverter 6 includes a conversion circuit for converting power, a rectifier circuit, and a drive circuit. The conversion circuit is configured by a circuit in which switching elements such as IGBTs are connected in a bridge shape, for example, and the drive circuit is a circuit for switching on and off of the switching elements. Further, the inverter 6 converts AC power output from the motor 7 into DC power and outputs it to the battery 1 during the regenerative operation of the motor 7. The inverter 6 is connected between the battery 1 and the motor 7.

  The motor 7 is a driving source of the vehicle, and is constituted by, for example, a three-phase synchronous motor. The motor 7 is connected to the inverter 6.

  The charger 8 is a device for charging the battery 1 with electric power input from the outside of the vehicle. The charger 8 is connected to, for example, a household power system by a cable or the like, converts the power of the power system into power suitable for charging the battery 1, and outputs the power to the battery 1. The charger 8 is connected to the battery 1.

  The first controller 10 is a battery controller for managing the state of the battery 1. The first controller 10 includes a memory 10a in which various programs are stored, and a CPU (Central Processing Unit) 10b as an operation circuit that executes the stored programs. The memory 10a includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The first controller 10 manages the full charge capacity of the battery 1, the capacity charged in the battery 1, the deterioration rate of the battery 1, etc. as the state of the battery 1. Moreover, the 1st controller 10 has the function to adjust the dispersion | variation between several cell batteries other than the management function of the battery 1. FIG. Further, the first controller 10 has a functional block for exhibiting the management function of the battery 1. Each functional block will be described later with reference to FIG. Information on the battery 1 managed by the first controller 10 is transmitted to the second controller 20.

  The second controller 20 is a controller for controlling the inverter 6 and the charger 8, and includes a memory 20a and a CPU 20b. The second controller 20 controls the inverter 6 so that the torque required based on the accelerator opening is output from the motor 7 when the motor 7 is powered. In addition, the second controller 20 causes the inverter 6 to input power suitable for charging the battery 1 to the battery 1 for the regenerative operation of the motor 7 according to the state of the battery 1 during the regeneration of the motor 7. To control. Further, the second controller 20 outputs a switching signal corresponding to switching between regeneration and power running of the motor 7 to the first controller 10. This switching signal is a signal indicating switching between charging and discharging of the battery 1. Further, the second controller 20 acquires information on the battery 1 from the first controller 10.

  When charging the battery 1 with the electric power of the external power source of the vehicle, the second controller 20 outputs a charge control signal indicating the start and end of charging to the first controller 10 while controlling the charger 8. To do. After the first controller 10 receives the charging start signal from the second controller 20, the first controller 10 manages the state of the battery 1 being charged using the detected value of the voltage sensor 2 or the like. Then, when the first controller 10 detects that the capacity of the battery 1 has reached full charge, the first controller 10 outputs a signal indicating full charge to the second controller 20. The second controller 20 stops the operation of the charger 8 based on the fully charged signal. In addition, the 1st controller 10 and the 2nd controller 20 may be comprised by one controller.

  Next, functional blocks of the first controller 10 will be described with reference to FIG. FIG. 2 is a block diagram of the voltage sensor 2, the current sensor 3, the temperature sensor 4, the capacity adjustment unit 5, and the first controller 10.

  The first controller 10 includes a condition determination unit 11, a current integrated value calculation unit 12, a dQ / dV calculation unit 13, an approximate SOC calculation unit 14, an SOC identification unit 15, dV as functional blocks for exhibiting a battery management function. / DSOC calculation unit 16, full charge capacity calculation unit 17, and deterioration rate calculation unit 18.

  The condition determination unit 11 determines whether or not the state of the battery 1 is a state suitable for calculating the full charge capacity of the battery 1 or the degree of deterioration of the battery 1. The condition determination unit 11 acquires the detection values of the voltage sensor 2, the current sensor 3, and the temperature sensor, and acquires the variation amount of the cell battery managed by the capacity adjustment unit 5. Moreover, the condition determination unit 11 acquires the SOC calculated by the approximate SOC calculation unit 14. Determination conditions are set in the condition determination unit 11 in advance. The determination condition is a condition for determining whether or not the state of the battery 1 is suitable for a calculation such as a full charge capacity. The determination condition includes a current condition of the battery 1, a temperature condition of the battery 1, an internal resistance condition of the battery 1, and a variation condition of the cell battery. Each specific condition will be described later. The condition determination unit 11 outputs the determination result to the dQ / dV calculation unit 13.

  The current integration value calculation unit 12 integrates the charge / discharge current of the battery 1 by integrating the detection current of the current sensor 3. The integrated current value calculation unit 12 outputs information on the integrated current value to the dQ / dV calculation unit 13 and the approximate SOC calculation unit 14.

  The dQ / dV calculation unit 13 calculates the change amount (dQ / dV) of the current integrated value per unit voltage of the battery 1 based on the integrated value calculated by the current integrated value calculating unit 12 and the detection voltage of the voltage sensor 2. Calculate. The change amount (dQ / dV) indicates the ratio between the change amount of the voltage between the terminals of the battery 1 and the change amount of the current integrated value.

  The approximate SOC calculation unit 14 acquires the detection voltage of the voltage sensor while acquiring the current integration value from the current integration value calculation unit 12. The approximate SOC calculation unit 14 calculates the current SOC of the battery 1 as the approximate SOC using at least one of the current integrated value and the detected voltage.

  When the SOC is calculated using the integrated current value, the calculated SOC includes current sensor errors and the like, and the calculation accuracy may be lower than the SOC calculated by the SOC specifying unit 15 described later. is there. When calculating the SOC based on the detection voltage, the approximate SOC calculation unit 14 calculates the SOC while referring to a map showing the relative relationship between the open circuit voltage and the SOC. Since the battery 1 is loaded, the terminal voltage of the battery 1 detected by the voltage sensor 2 is different from the open voltage. For this reason, the SOC calculated using the map may have a lower calculation accuracy than the SOC calculated by the SOC specifying unit 15 described later. In this example, the SOC calculation accuracy is improved by calculating the SOC by the SOC specifying unit 15 in addition to the approximate SOC calculation unit 14. In addition, in order to distinguish the SOC calculated by the SOC specifying unit 15, the SOC calculated by the approximate SOC calculation unit 14 is shown as an approximate SOC.

  The SOC specifying unit 15 acquires the approximate SOC from the approximate SOC calculation unit 14 while acquiring the amount of change (dQ / dV) from the dQ / dV calculation unit 13. Based on the SOC, the SOC specifying unit 15 calculates the SOC corresponding to the change amount (dQ / dV) as the specific SOC. In addition, the SOC specifying unit 15 refers to the map (SOC-dQ / dV map) stored in the memory 10a, and sets the SOC range that matches the amount of change (dQ / dV) within a predetermined period as the specific SOC range. Identify.

  The dV / dSOC calculation unit 16 acquires the specific SOC from the SOC specifying unit 15. The dV / dSOC calculation unit 16 calculates a change amount (dV / dSOC) corresponding to a specific SOC while referring to a map (SOC-dV / dSOC map) stored in the memory 10a. Further, the dV / dSOC calculation unit 16 refers to the map (SOC-dV / dSOC map), and calculates the amount of change (dV / dSOC) corresponding to a plurality of specific SOCs included in the specific SOC range for each specific SOC. Calculate. The change amount (dV / dSOC) indicates a ratio between the change amount of the voltage between the terminals of the battery 1 and the change amount of the SOC.

  The full charge capacity calculation unit 17 acquires the change amount (dV / dSOC) from the dV / dSOC calculation unit 16 while acquiring the change amount (dQ / dV) from the dQ / dV calculation unit 13. The full charge capacity calculation unit 17 calculates the full charge capacity of the battery 1 based on the change amount (dQ / dV) and the change amount (dV / dSOC). Further, when the full charge capacity calculation unit 17 calculates the full charge capacity based on a plurality of change amounts (dQ / dV) calculated within a predetermined period, the change amount calculated for each of a plurality of specific SOCs. The full charge capacity is calculated by associating (dV / dSOC) with a plurality of variations (dQ / dV).

  The deterioration rate calculation unit 18 acquires the full charge capacity from the full charge capacity calculation unit 17. The deterioration rate calculation unit 18 calculates the deterioration rate of the battery 1 by calculating the ratio between the acquired full charge capacity and the initial full charge capacity of the battery 1. The initial full charge capacity of the battery 1 is stored in the memory 10a.

  Next, control of the management function of the state of the battery 1 by the first controller 10 will be described with reference to FIGS. FIG. 3 is a graph showing a characteristic of the internal resistance with respect to the SOC of the battery 1. Graph a shows the characteristics when the battery temperature is high, and graph b shows the characteristics when the battery temperature is low.

  FIG. 4 is a graph showing characteristics of the amount of change (dQ / dV) with respect to the SOC of the battery 1. FIG. 5 is a graph showing characteristics of the gradient of the change amount (dQ / dV) with respect to the SOC of the battery 1. 4 and 5, graph a shows the characteristics of the battery 1 in the initial state, and graph b shows the characteristics of the battery 1 after deterioration. FIG. 6 is a graph showing characteristics of the amount of change (dV / dSOC) with respect to the SOC of the battery 1.

  The condition determination unit 11 determines whether a current condition for calculating a full charge capacity or the like is satisfied based on the detection current of the current sensor 3. The current condition is set in advance. The current condition is that the current value (detected current) is equal to or greater than the lower limit current value, and the amount of change in the current value during a predetermined time is within a certain range (predetermined current width). The lower limit current value is a threshold value of a preset current value, and is a lower limit value that can ensure the calculation accuracy of the current integrated value. The lower limit current value is set in consideration of the detection accuracy of the current sensor 3 or the resolution of AD conversion processed when the detection value of the sensor is output to the first controller 10. The lower limit current value is, for example, a current value that suppresses the integration accuracy of the current integration value within 1%.

  The predetermined time and the predetermined current width are threshold values that indicate that the polarization of the battery 1 is suppressed and the voltage of the battery 1 is stabilized by the charge / discharge time of the battery 1 and the fluctuation range of the current value.

  Here, the relationship between the terminal voltage (CCV) of the battery 1 and the open circuit voltage (OCV) will be described. In this example, as described below, the full charge capacity and the like are calculated using a map (SOC-dV / dSOC map). The voltage defined in this map is an open circuit voltage (no load voltage). On the other hand, the voltage detected by the voltage sensor 2 in a state where the battery 1 is loaded is an inter-terminal voltage (load voltage). Therefore, in order to increase the calculation accuracy of the full charge capacity, it is better that the fluctuation of the IR value (current × internal resistance of the battery 1), which is the difference between the terminal voltage and the open circuit voltage, is small. That is, if the fluctuation of the IR value is small, the fluctuation of the open circuit voltage can be grasped by the fluctuation of the voltage between terminals.

  The fluctuation of the IR value is caused by the polarization action of the battery 1. For example, immediately after the current of the battery 1 starts to flow, the polarization of the battery 1 gradually increases, so that the fluctuation range of the IR value increases. Further, for example, when the battery 1 is charged by an external power supply immediately after the vehicle is stopped, polarization due to discharge during vehicle travel remains. Immediately after the start of charging, the fluctuation range of the IR value increases due to the polarization of the battery 1.

  Therefore, the condition determination unit 11 determines that the current is detected when the detected current of the current sensor 3 is equal to or greater than the lower limit current value and the amount of change in the current value during a predetermined time is within a certain range (predetermined current width). It is determined that the condition is satisfied. When the current condition is not satisfied, the condition determination unit 11 determines that the current state of the battery 1 is not suitable for the calculation condition such as the full charge capacity, and the determination result is determined as the current integrated value calculation unit 12 and the dQ / The result is output to the dV calculation unit 13.

  When the dQ / dV calculating unit 13 acquires a signal indicating that the current condition is not satisfied, the dQ / dV calculating unit 13 does not calculate the amount of change (dQ / dV) based on the current voltage of the battery 1 or the like. Similarly, the full charge capacity calculation unit 17 and the deterioration rate calculation unit 18 do not perform calculation. That is, the first controller 10 calculates the full charge capacity when the current condition is satisfied, and does not calculate the full charge capacity when the current condition is not satisfied.

  Thereby, for example, when the load applied to the battery 1 fluctuates and the IR value fluctuates, or when the IR value of the battery 1 fluctuates due to the polarization of the battery 1 developing, the full charge capacity, etc. Therefore, the calculation accuracy of the state of the battery 1 is increased.

  The condition determination unit 11 determines whether a temperature condition for calculating a full charge capacity or the like is satisfied based on the temperature detected by the temperature sensor 4. The temperature condition is set in advance. The temperature condition is that the amount of change in battery temperature during a predetermined time is within a certain range (predetermined temperature range).

  The predetermined time and the predetermined temperature range are threshold values that indicate that the overall temperature of the battery 1 is stabilized after the temperature change of the battery 1 by the elapsed time and the width of the temperature change. For example, immediately after a high load is applied to the battery 1 and the temperature of the battery 1 rises, the temperature of the battery 1 decreases, and it takes time for the temperature to stabilize. Further, in some cell batteries in the battery 1, when a load is applied and the temperature distribution in the cell is biased, it takes time until the temperature distribution becomes uniform.

  The temperature of the battery 1 affects the internal resistance of the battery 1. When the temperature change of the battery 1 is large, the fluctuation of the internal resistance is also large, and the IR value is largely fluctuated.

  Therefore, the condition determination unit 11 determines that the temperature condition is satisfied when the change amount of the detection voltage of the temperature sensor 4 is within a certain range for a predetermined time. Further, the condition determination unit 11 determines that the temperature condition is not satisfied when the amount of change in the detected voltage of the temperature sensor 4 is within a certain range for a predetermined time, and determines the determination result as a current integrated value calculation unit. 12 and the output to the dQ / dV calculator 13. As in the case of the current condition, the dQ / dV calculation unit 13 does not calculate the amount of change (dQ / dV) based on the current voltage of the battery 1 or the like when the temperature condition is not satisfied.

  Thus, in this example, when the temperature of the battery 1 is not stable and the IR value is likely to fluctuate, the calculation of the state of the battery 1 is increased because the full charge capacity and the like are not calculated. .

  The condition determination unit 11 determines whether or not the cell battery variation condition for calculating the full charge capacity or the like is satisfied based on the variation amount between the cell batteries managed by the capacity adjustment unit 5. The variation condition is set in advance, and the variation amount is equal to or less than a predetermined value. The predetermined value is a threshold value of the variation condition, and is set in advance according to the characteristics of the cell battery.

  When variation occurs between cell batteries, the open voltage of each cell battery is different, and the SOC of each cell battery is also different. The voltage sensor 2 detects the total voltage of the cell batteries having different SOCs as the inter-terminal voltage of the battery 1. When the detection voltage of the voltage sensor 2 is used to calculate the full charge capacity of the battery 1, the calculation accuracy is lowered.

  Therefore, the condition determination unit 11 determines that the variation condition is satisfied when the variation amount is equal to or less than the predetermined value. On the other hand, when the variation amount is larger than the predetermined value, the condition determination unit 11 determines that the variation condition is not satisfied, and outputs the determination result to the current integrated value calculation unit 12 and the dQ / dV calculation unit 13. Similarly to the current and temperature conditions, the dQ / dV calculation unit 13 does not calculate the amount of change (dQ / dV) based on the current voltage of the battery 1 or the like when the variation condition is not satisfied.

  Thereby, in this example, when the difference in SOC between the cell batteries is large, the calculation accuracy of the state of the battery 1 is increased because the calculation of the full charge capacity and the like is not performed.

  The condition determination unit 11 determines whether or not the internal resistance condition of the battery 1 for calculating the full charge capacity or the like is satisfied based on the SOC of the battery 1. The internal resistance condition is set in advance, and the SOC is equal to or greater than a predetermined value (SOC threshold value). The condition determination unit 11 acquires the SOC of the battery 1 from the approximate SOC calculation unit 14.

  As shown in FIG. 3, the internal resistance of the battery 1 changes according to the SOC of the battery 1, and when the SOC is low, the internal resistance of the battery 1 increases. Further, in the example of FIG. 3, the internal resistance is particularly high when the SOC is 20% or less. And when internal resistance is high, IR value becomes large.

  Therefore, the condition determination unit 11 determines that the internal resistance condition is satisfied when the SOC of the battery 1 is higher than a predetermined value (20% in the example of FIG. 3). Moreover, the condition determination part 11 is. When the SOC is equal to or less than the predetermined value, it is determined that the internal resistance condition is not satisfied, and the determination result is output to the dQ / dV calculation unit 13. As in the case of the above condition, the dQ / dV calculation unit 13 does not calculate the amount of change (dQ / dV) based on the current voltage of the battery 1 or the like when the internal resistance condition is not satisfied.

  Thereby, in this example, since the calculation of the full charge capacity or the like is not performed in the SOC region where the internal resistance is large, the calculation accuracy of the state of the battery 1 is increased. As shown in FIG. 3, the characteristics of the internal resistance and SOC of the battery 1 are temperature dependent. Therefore, when the battery temperature is lower than the predetermined value, the SOC threshold value may be set higher than the predetermined threshold value, and when the battery temperature is higher than the predetermined value, the SOC threshold value may be set lower than the predetermined threshold value.

The current integrated value calculation unit 12 satisfies the above condition when charging or discharging of the battery 1 is started from the no-load state of the battery 1, when the current integrated value becomes higher than the integrated value threshold (Q _th ), or If the current integration is interrupted (hereinafter also referred to as “predetermined timing”), the current integration value is reset to zero and the current integration is started. Then, the integrated current value calculation unit 12 outputs the integrated current value after being reset at a predetermined timing to the dQ / dV calculation unit 13. On the other hand, the current integrated value calculation unit 12 calculates a current integrated value (integrated value of charge / discharge current of the battery 1) obtained by integrating the detected current of the current sensor without resetting at a predetermined timing. The current integrated value calculation unit 12 outputs a current integrated value corresponding to the integrated value of the charge / discharge current to the approximate SOC calculation unit 14.

The dQ / dV calculation unit 13 stores the voltage value detected by the voltage sensor in the memory 10a at the same timing as the predetermined timing among the detection voltages of the voltage sensor 2. For example, when the current is integrated during the period when the current integrated value reaches the integrated value threshold (Q _th ) from the time when charging or discharging of the battery 1 is started from the no-load state of the battery 1, The terminal voltage of the battery 1 and the terminal voltage of the battery 1 when the integrated value reaches the integrated value threshold (Q _th ) are stored in the memory 10a. Therefore, the difference between these two inter-terminal voltages is the amount of change in inter-terminal voltage during the current integration period.

The integrated value threshold value (Q _th ) is a threshold value that defines the current integrated value and the voltage change amount necessary for calculating the change amount (dQ / dV) with high accuracy. For example, when the integrated value threshold (Q _th ) is set to an extremely small value, the current integration period is shortened. When the integration period is shortened, the amount of change in voltage during the integration period is also reduced. Therefore, there is a possibility that the amount of change in voltage during the integration period is more influenced by the change in voltage value due to the resolution of the voltage sensor or the like than the voltage change during charging and discharging.

Further, when the integrated value threshold (Q _th ) is set to an extremely large value, the current integration period becomes long. When the integration period is long, the fluctuation range of the current of the battery 1 also increases. For this reason, since the integrated current value is reset before the integration period elapses, the number of data when calculating the change amount (dQ / dV) is reduced. Alternatively, there is a possibility that the charging of the battery 1 or the traveling of the vehicle is terminated before the current integrated value is calculated. Therefore, the integrated threshold value (Q _th ) is set to such an extent that the calculation accuracy of the fluctuation amount (dQ / dV) can be ensured.

  The dQ / dV calculation unit 13 calculates the difference between the detection voltage detected at the start point of the integration period of the current integration value and the detection voltage detected at the end point of the integration period. The amount of change (dV) in the inter-terminal voltage is calculated. Further, the dQ / dV calculation unit 13 calculates the change amount (dQ / dV) by calculating the ratio between the current integrated value (dQ) and the change amount (dV). The dQ / dV calculator 13 stores the calculated change amount (dQ / dV) in the memory 10a. The dQ / dV calculation unit 13 performs the above calculation at a predetermined cycle.

  When the SOC specifying unit 15 obtains the change amount (dQ / dV) and the approximate SOC, it corresponds to the change amount (dQ / dV) while referring to the map (SOC-dQ / dV map) stored in the memory 10a. The SOC to be specified is specified.

  The characteristic of graph a in FIG. 4 is the characteristic when dQ / dV is calculated for every 1 Ah when the battery 1 in the initial state is charged with a constant current (10 A) from the SOC (0%) state. It is shown as an example. Moreover, the characteristic of the graph b has shown the characteristic in the case similar to the graph a in the battery 1 of a deterioration rate (70%) with respect to the battery 1 of an initial state.

  The memory 10a stores a map (a characteristic map shown by the graph a in FIG. 4) indicating a correspondence relationship between the SOC and the change amount (dV / dSOC) at least in the initial state of the battery 1. Regarding the correspondence between the SOC after deterioration of the battery 1 and the amount of change (dV / dSOC), the first controller 10 uses the calculation result of the dQ / dV calculation unit 13 and the like according to the deterioration rate of the battery 1. While calculating the correspondence, the calculated correspondence is recorded in the memory 10a as a map (SOC-dQ / dV map). Alternatively, the correspondence relationship between the SOC and the amount of change (dV / dSOC) may be recorded in advance in the memory 10 a as a map corresponding to the deterioration rate of the battery 1.

  The SOC specifying unit 15 calculates the characteristic of the change amount (dQ / dV) within a predetermined period, and the calculated characteristic matches the characteristic of which part of the characteristics indicated by the map (SOC-dQ / dV map). Judge whether to do. In the predetermined period, the range to be matched with the characteristics of the map (SOC-dQ / dV map) is defined by time.

  For example, assume that the amount of change (dQ / dV) within a predetermined period has changed from a certain value to three times. At this time, from the characteristics shown in FIG. 4, the SOC range in which the amount of change (dQ / dV) can change three times is 47% or less. Not only in the initial state of the battery 1, but also when the battery 1 deteriorates according to the graph b, the SOC range in which the amount of change (dQ / dV) can change three times is limited. Further, the calculation target is a case where the SOC of the battery 1 is 20% or more from the internal resistance condition. Therefore, among the characteristics shown in the map (SOC-dQ / dV map), the SOC range that matches the amount of change (dQ / dV) within a predetermined period is between 20% and 47%.

  Further, the SOC specifying unit 15 can specify the SOC of the current battery 1 in the specified SOC range from the slope of the change amount (dQ / dV). As shown in graph a of FIG. 5, when the SOC range is 20% to 47%, the slope of the change amount (dQ / dV) is the smallest at SOC (26%), and SOC (37%). Becomes the largest. Therefore, the SOC specifying unit 15 specifies the SOC within the SOC range from the change in the slope of the change amount (dQ / dV) within the predetermined period. For example, when the slope of the amount of change (dQ / dV) within a predetermined time changes from decreasing to increasing, the SOC is specified as 26%. Then, if the SOC of one change amount (dQ / dV) among the plurality of change amounts (dQ / dV) within a predetermined period is specified, other change amounts (dQ / dV) are also shown in FIG. Can be calculated from the characteristics of the map (SOC-dQ / dV map) shown in FIG.

  As another example, the SOC range may be specified from a decrease in the amount of change (dQ / dV) within a predetermined period. For example, assume that the amount of change (dQ / dV) has decreased from a certain value to a value of 40%. At this time, the SOC range in which the change amount (dQ / dV) can be reduced to a value of 40% is 83% or more from the characteristics of FIG. Therefore, when the amount of change (dQ / dV) within a predetermined period decreases from a certain value to a value of 40%, the SOC specifying unit 15 specifies the SOC range as 83% or more.

  Furthermore, the SOC can be specified from the characteristics of the slope. When the SOC is specified from the slope of the change amount (dQ / dV), the slope change amount is not limited to increase / decrease of the slope. For example, when the SOC range is specified in the range of 47% to 69%, the amount of decrease in the slope is a single change amount (dQ / Suppose that the voltage becomes smaller at dV). As shown in FIG. 5, when the SOC is 53%, the slope changes from a steep decrease to a gradual decrease. Therefore, SOC is specified as 53 percent out of the SOC range (47% to 69%). In addition, although the said specific example demonstrated the battery 1 of the initial state, the SOC range can be specified also about the battery 1 of a degradation degree similarly to the above.

  In addition, the SOC specifying unit 15 calculates the characteristics between the SOC calculated by the approximate SOC calculation unit 14 and the amount of change (dQ / dV) within a predetermined time, and the calculated characteristics are mapped (SOC-dQ / dV map). It may be determined which part of the characteristics indicated by The SOC specifying unit 15 specifies an approximate SOC corresponding to a plurality of changes (dQ / dV) within a predetermined time. The SOC specifying unit 15 calculates a characteristic from the transition of the change amount (dQ / dV) with respect to the change amount of the approximate SOC. And the SOC specific | specification part 15 determines with which characteristic the calculated characteristic is suitable among the characteristics shown by a map (SOC-dQ / dV map). Thereby, the SOC specific | specification part 15 can specify a SOC range.

  When the SOC range cannot be specified by the above-described specifying method, the SOC specifying unit 15 accumulates data of a new change amount (dQ / dV) until the SOC can be specified. For example, it is assumed that the amount of change (dQ / dV) within a predetermined period has decreased by 50% from a certain value. At this time, from the characteristics shown in FIG. 4, the SOC range in which the variation (dQ / dV) is reduced by 50% is two ranges of 47% to 69% and 83% or more. Furthermore, it is assumed that the slope of the change amount (dQ / dV) is monotonously decreasing at a constant rate. In such a case, since the SOC range cannot be specified as one range even from the slope of the change amount (dQ / dV), the SOC specifying unit 15 further accumulates data of the change amount (dQ / dV).

  When the SOC range is specified by the SOC specifying unit 15, the dV / dSOC calculation unit 16 refers to a map (SOC-dQ / dV map) stored in the memory 10 a and changes (dV) that match the SOC range. / DSOC). When there are a plurality of change amounts (dQ / dV) within a predetermined period, when the SOC range is specified, SOCs corresponding to the plurality of change amounts (dQ / dV) are specified within the specified SOC range. The The dV / dSOC calculation unit 16 calculates each dV / dSOC with reference to the map for the plurality of specified SOCs.

Next, when the change amount (dQ / dV) is calculated by the dQ / dV calculation unit 13 and the change amount (dV / dSOC) is calculated by the dV / dSOC calculation unit 16, the full charge capacity calculation unit 17 As shown in the equation (1), the product of the change amount (dQ / dV) and the change amount (dV / dSOC) is obtained, so that the change amount of the capacity (dQ (Ah)) of the battery 1 and the SOC of the battery 1 are calculated. The ratio (dQ / dSOC) to the amount of change (dSOC (%)) is calculated.
dQ / dSOC [Ah /%] = (dQ / dV) × (dV / dSOC) (1)

Then, the full charge capacity calculation unit 17 calculates the full charge capacity corresponding to the current integration point where the SOC corresponds to 0% to 100%. The full charge capacity is obtained by multiplying the calculation result of Expression (1) by 100, as shown in Expression (2).
Full charge capacity = (dQ / dSOC) × 100 (2)

  When there are a plurality of change amounts (dQ / dV) within a predetermined period, a plurality of SOCs corresponding to the change amount (dQ / dV) are also specified, and the change amount (dV / dSOC) with respect to the specified SOC. ) Are also calculated multiple times. Therefore, the full charge capacity calculation unit 17 uses the equations (1) and (2) to match the respective full charge capacities using the change amounts (dQ / dV) and the change amounts (dV / dSOC). Calculate. Then, the full charge capacity calculation unit 17 calculates the average full charge capacity of each battery 1 to calculate the current full charge capacity of the battery 1.

  Next, the calculation control of the full charge capacity will be described with reference to FIG. FIG. 7 is a table for explaining calculation results of the dQ / dV calculating unit 13, the SOC specifying unit 15, the dV / dSOC calculating unit 16, and the full charge capacity calculating unit 17.

  For example, it is assumed that the dQ / dV calculation unit 13 sequentially calculates the change amount (dQ / dV) as 0.5, 1.2, 1.3, and 1.1 during a predetermined period during charging of the battery 1. . At this time, the battery 1 has deteriorated from the initial state, and the characteristics of the battery 1 are indicated by the characteristics of the graph b in FIGS. 4 and 5.

  The SOC specifying unit 15 corresponds to the dQ / dV change amount (0.5, 1.2, 1.3, 1.1) while referring to the map (SOC-dQ / dV) recorded in the memory 10a. Specify the SOC (30%, 40%, 50%, 60%).

  Next, the dV / dSOC calculation unit 16 sets the SOC (30%), (40%), (50%), and (60%) while referring to the map (SOC-dQ / dV map) shown in FIG. The corresponding change amounts (dV / dSOC) are calculated as 0.7, 0.35, 0.35, and 0.45, respectively.

  Then, the full charge capacity calculation unit 17 calculates Equation (1) and Equation (2) from the dQ / dV change amount (0.5) and the dV / dSOC change amount (0.7) when the SOC is 30%. And the full charge capacity is calculated as 35 (Ah). Similarly, the full charge capacity calculation unit 17 calculates the full charge capacity (42 Ah, 45.5 Ah, 49.5 Ah) for other SOCs (40%, 50%, 60%). Finally, the full charge capacity calculation unit 17 calculates the average value of the calculated full charge capacities (35 Ah, 42 Ah, 45.5 Ah, 49.5 Ah), thereby calculating the full charge capacity as 43 Ah.

  Next, the control flow of the battery 1 state management function will be described with reference to FIG. FIG. 8 is a flowchart showing a control procedure of the first controller 10. Note that the control flow of FIG. 8 is repeatedly performed at a predetermined cycle.

  In step S1, the first controller 10 acquires a detection value (sensor value) of the voltage sensor 2 or the like. In step S2, the condition determination unit 11 determines whether or not the current condition is satisfied based on the acquired detection value. If the current condition is satisfied, the condition determination unit 11 determines whether or not the temperature condition is satisfied in step S3. If the temperature condition is satisfied, in step S4, the condition determination unit 11 determines whether or not the cell battery variation condition is satisfied. If the cell battery variation condition is satisfied, the condition determination unit 11 determines whether or not the internal resistance condition is satisfied in step S5.

  If the internal resistance condition is satisfied, the process proceeds to step S6. On the other hand, if the current condition, temperature condition, cell battery variation condition, or internal resistance condition is not satisfied, the process returns to step S1.

In step S6, the integrated current value calculator 12 calculates the integrated current value (Q). At step S7, whether the current integral calculation unit 12 compares the current integrated value (Q) and the cumulative value threshold _{(Q th),} is the current integrated value (Q) is the integrated value threshold _{(Q th)} or higher Determine whether or not. If the current integrated value (Q) is less than the integrated value threshold (Q _th ), the process returns to step S1.

On the other hand, if the current integrated value (Q) is equal to or greater than the integrated value threshold (Q _th ), in step S8, the dQ / dV calculator 13 calculates the amount of change (dQ / dV). In step S9, the SOC specifying unit 15 specifies the SOC corresponding to the calculated change amount (dQ / dV) while referring to the map (SOC-dQ / dV map).

  In step S10, the SOC specifying unit 15 determines whether or not the SOC has been specified. For example, when a plurality of calculation results of the SOC range or the SOC are calculated and it is not possible to specify one SOC from a plurality of calculation results from the slope of the change amount (dQ / dV) or the approximate SOC, the SOC specifying unit 15 , It is determined that the SOC cannot be specified, and the process returns to step S1.

  On the other hand, when it is determined that the SOC can be specified, in step S11, the dV / dSOC calculation unit 16 calculates the amount of change (dV / dSOC). In step S12, the full charge capacity calculation unit 17 calculates the full charge capacity of the battery 1 based on the change amount (dV / dSOC) and the change amount (dQ / dV). In step S13, the deterioration rate calculation unit 18 calculates the deterioration rate of the battery 1 based on the calculated full charge capacity. Then, the first controller 10 ends the control flow.

  As described above, in this example, the change amount (dQ / dV) is calculated based on the detection current of the current sensor 3 and the detection voltage of the voltage sensor, and the SOC corresponding to the change amount (dQ / dV) is set as the specific SOC. The change amount (dV / dSOC) corresponding to the specific SOC is calculated with reference to the map (SOC-dQ / dV map), and the change amount (dV / dSOC) and the change amount (dQ / dV), the full charge capacity of the battery 1 is calculated. Thereby, since the range of SOC which is the calculation target of the full charge capacity can be widened, it is not necessary to charge / discharge the battery 1 unnecessarily in order to calculate the state of the battery 1. As a result, the time for detecting the state of the battery 1 can be shortened.

  In this example, the SOC range that matches the amount of change within a predetermined period is specified as the specific SOC range while referring to the map (SOC-dV / dSOC), and the map (SOC-dQ / dV map) is referred to. In addition, the amount of change (dV / dSOC) is calculated for each SOC included in the range of the characteristic SOC, and the full charge capacity of the battery 1 is determined while corresponding the amount of change (dQ / dV) and the amount of change (dV / dSOC). Calculate. As a result, it is possible to widen the SOC range that is the target of calculation of the full charge capacity. In this example, since the full charge capacity is calculated using a plurality of change amounts (dQ / dV) and change amounts (dV / dSOC), the calculation accuracy of the full charge capacity is increased.

In this example, when calculating the amount of change (dQ / dV), the integrated value of the detection voltage of the current sensor 3 is set to be equal to or greater than the integrated threshold value (Q _th ). For example, it is conceivable that the current integrated value when calculating the change amount (dQ / dV) is divided not by the current value but by time. However, when divided by time, for example, if the current value within the time is small, the integrated current value is also small, and the amount of change in voltage is also small. Therefore, the calculation error of the change amount (dQ / dV) becomes large. Further, when the voltage change amount or the current integrated value is low, the sensor resolution is easily affected. On the other hand, in this example, since the threshold value of the current integrated value when calculating the amount of change (dQ / dV) is defined by the current value, the calculation accuracy such as the full charge capacity can be improved.

  In this example, the slope of the change amount (dQ / dV) within a predetermined period is associated with the slope of the change amount (dQ / dV) indicated by the map (SOC-dQ / dV map), and the SOC range Is identified. Thereby, in this example, since the SOC range is specified by adding the gradient of the change amount (dQ / dV), the calculation accuracy of the SOC corresponding to the change amount (dQ / dV) is increased. As a result, the calculation accuracy of the full charge capacity can be improved.

  Further, in this example, when the SOC range that matches the amount of change (dQ / dV) within a predetermined period cannot be specified while referring to the map (SOC-dQ / dV map), the newly detected voltage sensor 2 and the like A new change amount (dQ / dV) is calculated using the detected value. Then, the SOC is specified with reference to the map (SOC-dQ / dV map) while adding the new change amount (dQ / dV) to the change amount (dQ / dV) in the predetermined period. Thus, in this example, the amount of change (dQ / dV) is continuously calculated until the SOC is specified, and is added to the calculation target when specifying the SOC, so that the calculation accuracy when specifying the SOC can be improved. .

  In this example, the condition determination unit 11 may set a predetermined current width or a predetermined time included in the current condition according to the SOC or voltage of the battery 1. In the SOC-OCV curve, the change amount (dV) of the voltage of the battery 1 is small in a portion with a small curvature. When the fluctuation range of the IR value due to the polarization of the battery 1 is large, the amount of change (dV) in the voltage of the battery 1 is more influenced by the voltage fluctuation due to the polarization action than the voltage fluctuation due to charging / discharging of the battery 1. . Therefore, for example, when the voltage of the battery 1 is in a band where the voltage fluctuation is small, the condition determination unit 11 makes the current width of the current condition smaller than a predetermined value and the voltage of the battery 1 is not in a band where the voltage fluctuation is small. For this, the current width of the current condition is set higher than the predetermined value. The band with a small voltage fluctuation is a voltage range set according to the characteristics of the battery 1.

  Alternatively, when the voltage of the battery 1 is in a band where the voltage fluctuation is small, the condition determination unit 11 shortens the predetermined time of the current condition from a predetermined value and the voltage of the battery 1 is not in a band where the voltage fluctuation is small. Makes the predetermined time of the current condition longer than the predetermined value. The condition determination unit 11 may change the current condition in the same manner as described above according to the SOC instead of the voltage.

  The condition determination unit 11 may set a predetermined current width or a predetermined time included in the current condition according to the internal resistance of the battery 1. When the internal resistance of the battery 1 is high, the IR value is also high. Therefore, when the internal resistance of the battery 1 is higher than the predetermined resistance value, the condition determination unit 11 makes the current width of the current condition smaller than the predetermined value, and the internal resistance of the battery 1 is lower than the predetermined resistance value. For this, the current width of the current condition is set higher than the predetermined value.

  Alternatively, when the internal resistance of the battery 1 is higher than a predetermined resistance value, the condition determination unit 11 shortens the predetermined time of the current condition from the predetermined value, and the internal resistance of the battery 1 is lower than the predetermined resistance value. The predetermined time of the current condition is made longer than the predetermined value. The internal resistance of the battery 1 may be calculated using the detection value of the sensor. Further, as shown in FIG. 3, the internal resistance of the battery 1 depends on the SOC and temperature of the battery 1. Therefore, the internal resistance may be estimated from the SOC or temperature of the battery 1.

  Moreover, the condition determination part 11 may set the predetermined time prescribed | regulated by electric current conditions according to the deterioration rate of the battery 1, the temperature of the battery 1, or the presence or absence of the switching of charging / discharging to the battery 1. FIG. The polarization characteristics (polarization saturation time) of the battery 1 depend on the temperature and deterioration rate of the battery 1. Therefore, the condition determination unit 11 sets the predetermined time for the current condition to a longer time as the temperature of the battery 1 is higher or the deterioration rate of the battery 1 is higher.

  Further, immediately after the charging and discharging of the battery 1 are switched, it takes time until the polarization of the battery 1 is stabilized. Therefore, the condition determination unit 11 makes the predetermined time longer than a predetermined threshold time when there is a charge / discharge switching to the battery 1, and sets the predetermined time when there is no charge / discharge switching to the battery 1. Shorter than the threshold time.

  Thereby, the current conditions are varied in consideration of the temperature of the battery 1, the deterioration rate, or whether charging / discharging is switched or not, so that the calculation accuracy such as the full charge capacity can be improved.

In this example, the integrated threshold value (Q _th ) may be set so that the calculation accuracy of the voltage change amount (dV) can be ensured in the initial state of the battery 1. When the battery 1 deteriorates, the amount of change (dV) increases. Therefore, if at least the calculation accuracy of the amount of change (dV) in the initial state of the battery 1 can be ensured, it is possible to cope with the deterioration of the battery 1.

Further, the integrated threshold value (Q _th ) may be set according to the state of the battery 1 in the SOC-OCV curve. For example, when the state of the battery 1 is in a place where the slope of the SOC-OCV curve is steep, the amount of change in voltage becomes larger than the amount of change in SOC. Therefore, the integration threshold value (Q _th ) is set so that the accuracy of the current integration value can be ensured. On the other hand, when the slope of the SOC-OCV curve is moderate, the amount of change in voltage is smaller than the amount of change in SOC. Therefore, the integrated threshold value (Q _th ) is set so that the accuracy of the voltage change amount can be ensured.

  Note that the full charge capacity calculation unit 17 may calculate the current full charge capacity of the battery 1 using a weighted average or the like using the full charge capacity calculated at the previous calculation timing. Similarly, the deterioration rate calculation unit 18 may calculate the current deterioration rate of the battery 1 by a weighted average or the like using the deterioration rate calculated at the previous calculation timing.

  The SOC specifying unit 15 uses the map (SOC-dQ / dV map) to specify the SOC that matches the amount of change (dQ / dV) within the predetermined period, but the SOC calculating unit 14 calculates the SOC. The SOC may be calculated as a specific SOC. That is, in this example, in order to increase the calculation accuracy of the SOC, the map calculation by the SOC specifying unit 15 is used. However, when the calculation accuracy of the approximate SOC calculation unit 14 satisfies the requirement for the calculation accuracy of the SOC, the map calculation is performed. It is not always necessary to use an operation.

  The memory 10a corresponds to the “storage unit” of the present invention, and the first controller 10 corresponds to the “calculation unit” of the present invention.

<< Second Embodiment >>
A battery management apparatus according to another embodiment of the present invention will be described. The present invention differs from the first embodiment described above in some control of the SOC specifying unit 15, the dV / dSOC calculation unit 16, and the full charge capacity calculation unit 17. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

  The SOC specifying unit 15 of the first controller 10 refers to the map (SOC-dQ / dV map), and when there are a plurality of ranges that match the amount of change (dQ / dV) in a predetermined period, the approximate SOC calculation unit 14 The SOC is specified using the result of the calculation (approximate SOC).

  Hereinafter, specific control of the SOC specifying unit 15 will be described with reference to FIG. FIG. 9 is a graph showing the characteristic of the change amount (dQ / dV) with respect to the SOC of the battery 1. In FIG. 9, graph a shows the characteristics of the battery 1 in the initial state, and graph b shows the characteristics of the deterioration degree of the battery 1.

  For example, it is assumed that the amount of change (dQ / dV) within a predetermined period changes twice from a certain value in a state where the battery 1 has deteriorated to some extent (state of graph b in FIG. 9). At this time, from the characteristics shown in FIG. 9, two SOC ranges in which the amount of change can be doubled are specified in a range of 50% or less and a range of 70% to 86%. Therefore, the SOC specifying unit 15 cannot specify one SOC range only by referring to the map (SOC-dQ / dV map).

  In such a case, the SOC specifying unit 15 acquires the approximate SOC calculated by the approximate SOC calculation unit 14 at the same timing as the timing when the change amount (dQ / dV) is calculated. For example, when the estimated SOC is 80% and the range of calculation accuracy of the estimated SOC is in the range of −5% to + 5%, the SOC specifying unit 15 starts from 70% of the two SOC ranges. A range of up to 86% is specified as the SOC range.

  Next, the control of the SOC specifying unit 15 when the battery 1 has the characteristics shown in FIG. 10 will be described. FIG. 10 is a graph showing characteristics of the amount of change (dQ / dV) with respect to the SOC of the battery 1. In FIG. 10, graph a shows the characteristics of the battery 1 in the initial state, and graph b shows the characteristics of the degree of deterioration of the battery 1.

  For example, it is assumed that the amount of change (dQ / dV) within a predetermined period changes at a constant value in a state where the battery 1 has deteriorated to some extent (the state of the graph b in FIG. 10). At this time, from the characteristics shown in FIG. 10, two SOC ranges in which the amount of change changes at a constant value are specified in a range from 23% to 50% and a range from 52% to 90%.

For example, it is assumed that the approximate SOC is 50%, and the range of calculation accuracy when the approximate SOC is 50% is in the range of −5% to + 5%. In this case, the SOC specifying unit 15 cannot specify which SOC range of the two SOC ranges. Therefore, the SOC specifying unit 15 acquires a new change amount (dQ / dV) from the dQ / dV calculation unit,
The number of data of the change amount (dQ / dV) within the predetermined period is increased. The SOC specifying unit 15 acquires a new change amount (dQ / dV) until the change amount (dQ / dV) increases or decreases from a constant value to a different value.

  For example, when the amount of change (dQ / dV) increases from a constant value while the SOC increases due to charging of the battery 1, the SOC range is specified as a range from 23% to 50%. For example, when the amount of change (dQ / dV) decreases from a constant value while the SOC increases due to charging of the battery 1, the SOC range is specified as a range from 52% to 90%.

  As shown in FIG. 10, when the characteristic of the change amount (dQ / dV) with respect to the SOC changes as a characteristic of the battery 1, the SOC specifying unit 15 sets the change amount (dQ / dV) to the change amount (dQ / dV). If the corresponding SOC can be specified in the SOC range, the dV / dSOC calculation unit 16 can calculate the amount of change (dV / dSOC), and the full charge capacity calculation unit 17 can calculate the full charge capacity.

  Hereinafter, control of the dV / dSOC calculation unit 16 and control of the full charge capacity calculation unit 17 will be described with reference to FIGS. 10 and 11. FIG. 11 is a graph showing characteristics of the amount of change (dV / dSOC) with respect to the SOC of the battery 1. Note that the characteristics shown in FIG. 11 are based on the ratio between the SOC change amount and the open circuit voltage change amount (change amount (dV / dSOC)) when the battery 1 has the characteristics shown in FIG. Is the characteristic with the horizontal axis.

  For example, it is assumed that the SOC range is specified as a range from 23% to 50% as described above. Further, it is assumed that the calculation accuracy range of the approximate SOC is in the range of −5% to + 5%. Therefore, from the calculation accuracy of the SOC range and the approximate SOC, when the approximate SOC is in the range of 27% to 45%, the dQ / dV calculation unit 13 has acquired the amount of change (dQ / dV).

  In the map shown in FIG. 11 (SOC-dV / dSOC map), when the SOC range is 27% to 45%, the amount of change (dV / dSOC) is a constant value (0.57). Become. Therefore, the dV / dSOC calculation unit 16 calculates the dV / dSOC change amount (0.57) corresponding to the SOC range (27% to 45%) while referring to the map (SOC-dV / dSOC map).

  The full charge capacity calculation unit 17 calculates the full charge capacity from the dV / dSOC change amount (0.57) and the dQ / dV change amount (0.59) by using the equations (1) and (2). Calculate as (Ah).

  As described above, in this example, a plurality of SOC ranges that match the amount of change (dQ / dV) within a predetermined period are specified within the SOC range indicated by the map (SOC-dQ / dV map). The range including the approximate SOC is specified as the specific SOC range. Thereby, the calculation precision of SOC at the time of specifying SOC becomes high. As a result, the calculation accuracy of the full charge capacity can be improved.

  In addition, the present example includes a characteristic in which the characteristic of the relative relationship indicated by the map (SOC-dQ / dV map) changes at a constant change amount (dQ / dV) with respect to the SOC depending on the battery performance of the battery 1. When the characteristic of the relative relationship shown by (SOC-dV / dSOC map) includes a characteristic that changes with a constant change amount (dV / dSOC) with respect to the SOC, the change amount (dQ of a constant value within a predetermined period). / DV) is specified, and a constant value change amount (dV / dSOC) corresponding to the specified SOC range is calculated, and a constant value change amount (dQ / dV) and a constant value change are calculated. Based on the amount (dV / dSOC), the full charge capacity of the battery 1 is calculated.

  Thereby, the full charge capacity can be calculated without waiting for increase / decrease in the change amount (dQ / dV). As a result, the time for detecting the state of the battery 1 can be shortened.

<< Third Embodiment >>
A battery management apparatus according to another embodiment of the present invention will be described. The present invention differs from the above-described first embodiment in a part of the control of the SOC specifying unit 15. Other configurations are the same as those of the first embodiment described above, and the descriptions of the first and second embodiments are incorporated as appropriate.

  The SOC specifying unit 15 of the first controller 10 specifies a range that matches the amount of change (dQ / dV) within a predetermined period, and determines the SOC of the current battery 1 from the change amount (dQ / dV) maximum or minimum point. Identifies which SOC is in the specified SOC range.

  Hereinafter, specific control of the SOC specifying unit 15 will be described with reference to FIG. FIG. 12 is a graph showing the characteristic of the change amount (dQ / dV) with respect to the SOC of the battery 1. In FIG. 12, the graph a shows the characteristics of the battery 1 in the initial state, and the graph b shows the characteristics of the deterioration degree of the battery 1.

  For example, in a state in which the battery 1 has deteriorated to some extent (the state of graph b in FIG. 12), the amount of change (dQ / dV) within a predetermined period increases as the SOC increases, and decreases at the maximum point To do. The SOC specifying unit 15 specifies the maximum point of the change amount (dQ / dV) from the change of the change amount (dQ / dV). As shown in graph b of FIG. 12, there are two maximum points of change (dQ / dV) when SOC (48%) and SOC (84%). When the characteristics before and after the maximum point are compared between the two points, the characteristics before and after the SOC (48%) change more slowly than the characteristics before and after the SOC (84%). Therefore, the SOC specifying unit 15 calculates an increase / decrease amount of the change amount (dQ / dV) when two maximum points of the change amount (dQ / dV) are specified. When the increase / decrease amount is equal to or greater than the predetermined value, the SOC specifying unit 15 specifies the SOC of the battery 1 as 84%. On the other hand, when the increase / decrease amount is less than the predetermined value, the SOC specifying unit 15 specifies the SOC of the battery 1 as 48%.

  Further, for example, in a state where the battery 1 has deteriorated to some extent (the state of graph b in FIG. 12), the amount of change (dQ / dV) within a predetermined period decreases as the SOC increases, and increases from the minimum point as a boundary. Suppose that The SOC specifying unit 15 specifies the minimum point of the change amount (dQ / dV) from the change of the change amount (dQ / dV). As shown in the graph b of FIG. 12, there is one minimum point of change (dQ / dV) when the SOC is 70%. Therefore, the SOC specifying unit 15 specifies the SOC of the battery 1 as 70% when the minimum point of the change amount (dQ / dV) is specified.

  As described above, the SOC specifying unit 15 associates the maximum point of the change amount (dQ / dV) within the predetermined period with the maximum point indicated by the map (SOC-dQ / dV map), and calculates the SOC with respect to the maximum point. Identify. Further, the SOC specifying unit 15 specifies the SOC for the minimum point by associating the minimum point of the change amount (dQ / dV) within the predetermined period with the minimum point indicated by the map (SOC-dQ / dV map). . Thereby, the calculation precision of SOC can be improved. Further, since the SOC is identified quickly, the frequency of calculating the full charge capacity can be improved even when the battery 1 is used for a short time.

  As a modification of the present invention, the SOC specifying unit 15 specifies the SOC using the approximate SOC in addition to the maximum or minimum point of the change amount (dQ / dV) as described above. For example, the SOC specifying unit 15 specifies the maximum point of the change amount (dQ / dV) from the change of the change amount (dQ / dV) within a predetermined period.

  For example, it is assumed that the approximate SOC calculated by the approximate SOC calculation unit 14 is 50%, and the calculation accuracy range of the approximate SOC is in the range of −5% to + 5%. As shown in the graph b of FIG. 12, on the map (SOC-dQ / dV map), the maximum points of the variation (dQ / dV) are when SOC (48%) and when SOC (84%). Although there are two points, the SOC specifying unit 15 can specify the SOC for the maximum point as 48% from the estimated SOC (50%).

  As another example, for example, it is assumed that the approximate SOC calculated by the approximate SOC calculation unit 14 is 85%, and the range of calculation accuracy of the approximate SOC is in the range of −5% to + 5%. In such a case, the SOC specifying unit 15 can specify the SOC with respect to the maximum point as 84% from the estimated SOC (85%).

  In addition, when the SOC specifying unit 15 specifies the maximum point or the minimum point of the change amount (dQ / dV), not only the increase / decrease amount of the change amount (dQ / dV) but also the change amount (dQ / dV), for example. ) And the change value (previous value) of the change amount (dQ / dV) are calculated, and the time when the sign of the difference is inverted as the battery 1 is charged or discharged is specified. Thus, the maximum point or the minimum point of the change amount (dQ / dV) may be specified. Thereby, the precision of SOC can be raised. Further, since the SOC is identified quickly, the frequency of calculating the full charge capacity can be improved even when the battery 1 is used for a short time.

DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Voltage sensor 3 ... Current sensor 4 ... Temperature sensor 5 ... Capacity adjustment part 6 ... Inverter (INV)
DESCRIPTION OF SYMBOLS 7 ... Motor 8 ... Charger 10 ... 1st controller 11 ... Condition determination part 12 ... Current integration value calculating part 13 ... dQ / dV calculating part 14 ... Approximate SOC calculating part 15 ... SOC specific | specification part 16 ... dV / dSOC calculating part 17 ... Full charge capacity calculation unit 18 ... Deterioration rate calculation unit

Claims (14)

A current sensor for detecting the current of the battery;
A voltage sensor for detecting the voltage of the battery;
Calculation means for calculating the SOC of the battery and the full charge capacity of the battery based on the detection value of the current sensor or the voltage sensor;
Storage means for storing a first map showing a relative relationship between the change amount of the voltage per unit SOC of the battery (dV / dSOC) and the SOC;
The computing means is
Based on the detected current of the current sensor and the detected voltage of the voltage sensor, a change amount (dQ / dV) of the integrated value of the detected current per unit voltage of the battery is calculated,
An SOC corresponding to the amount of change (dQ / dV) is specified as a specific SOC,
Calculating the amount of change (dV / dSOC) corresponding to the specific SOC while referring to the first map;
A battery management device that calculates the full charge capacity based on the amount of change (dV / dSOC) and the amount of change (dQ / dV) corresponding to the specific SOC. The battery management device according to claim 1,
The storage means
Storing a second map showing a relative relationship between the SOC and the amount of change (dQ / dV);
The computing means is
While referring to the second map, the SOC range that matches the amount of change (dQ / dV) within a predetermined period is specified as a specific SOC range,
While calculating the change amount (dV / dSOC) for each of the specific SOCs included in the specific SOC range while referring to the first map,
The full charge capacity is calculated by associating the amount of change (dQ / dV) within the predetermined period with the amount of change (dV / dSOC) calculated for each specific SOC. Management device. The battery management device according to claim 2,
The battery management device according to claim 1, wherein an integrated value of the detected currents within the predetermined period is equal to or greater than a predetermined value. In the battery management device according to claim 2 or 3,
The computing means is
The specific SOC range is specified by associating the slope of the change amount (dQ / dV) within the predetermined period with the slope of the change amount (dQ / dV) shown in the second map. A battery management device. In the battery management device according to any one of claims 2 to 4,
The computing means is
While referring to the second map, if the SOC range that matches the amount of change (dQ / dV) within a predetermined period cannot be specified, a new amount of change (dQ / dV) is calculated,
A battery management device, wherein the specific SOC is specified with reference to the second map while adding the new change amount (dQ / dV) to the change amount (dQ / dV) within the predetermined period. The battery management device according to claim 2,
The computing means is
Based on the detected current of the current sensor and the detected voltage of the voltage sensor, an approximate value of the SOC is calculated,
When a plurality of ranges of the SOC that match the amount of change (dQ / dV) within a predetermined period are specified within the range of the SOC shown in the second map, the range including the approximate value Is specified as the specific SOC range. The battery management device according to claim 2,
The computing means is
The SOC corresponding to the local maximum point is specified as the specific SOC by associating the local maximum point of the amount of change (dQ / dV) within the predetermined period with the local maximum point shown in the second map, or
The minimum point of the amount of change (dQ / dV) within the predetermined period is associated with the minimum point indicated by the second map, and the SOC for the minimum point is specified as the specific SOC. Battery management device. The battery management device according to claim 1,
The storage means
Storing a second map showing a relative relationship between the SOC and the amount of change (dQ / dV);
The characteristic of the relative relationship recorded in the first map includes a characteristic that changes at a constant change amount (dV / dSOC) with respect to the SOC.
The characteristics of the relative relationship stored in the second map include a characteristic that changes at a constant amount of change (dQ / dV) with respect to the SOC.
The computing means is
While referring to the second map, the range of the SOC that matches the amount of change (dQ / dV) of the constant value within a predetermined period is specified as a specific SOC range,
While calculating the change amount (dV / dSOC) corresponding to the specific SOC range while referring to the first map,
A battery management device that calculates the full charge capacity based on the amount of change (dV / dSOC) corresponding to the specific SOC range and the amount of change (dQ / dV) of the constant value. In the battery management device according to any one of claims 1 to 8,
The computing means is
The battery management device, wherein the change amount (dQ / dV) is calculated when the change amount of the current detected by the current sensor is within a certain range for a predetermined time. The battery management device according to claim 9, wherein
The computing means is
The battery management device, wherein the predetermined time is set according to a degree of deterioration of the battery, a detected temperature of the battery, or whether charging / discharging of the battery is switched. In the battery management device according to any one of claims 1 to 10,
A temperature sensor for detecting the temperature of the battery;
The computing means is
The battery management device, wherein the change amount (dQ / dV) is calculated when the change amount of the temperature detected by the temperature sensor is within a certain range for a predetermined time. In the battery management device according to any one of claims 1 to 11,
Cell capacity management means for managing the capacity of a plurality of cell batteries included in the battery,
The computing means is
A battery management device that calculates the amount of change (dQ / dV) when a variation amount indicating a variation in capacity of the plurality of cell batteries is a predetermined value or less. In the battery management device according to any one of claims 1 to 12,
The computing means is
A battery management device that calculates the amount of change (dQ / dV) when the SOC is equal to or greater than a predetermined value. In a method for managing battery status,
The current sensor detects the battery current,
The voltage of the battery is detected by a voltage sensor,
Based on the detected current of the current sensor and the detected voltage of the voltage sensor, a change amount (dQ / dV) of the integrated value of the detected current per unit voltage of the battery is calculated,
An SOC corresponding to the change amount (dQ / dV) is specified as a specific SOC, and a map showing the relative relationship between the change amount (dV / dSOC) of the voltage per unit SOC of the battery and the SOC is referred to. , Calculating the amount of change (dV / dSOC) corresponding to the specific SOC,
A battery management method comprising: calculating a full charge capacity of the battery based on the specified change amount (dV / dSOC) and the change amount (dQ / dV).

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