JP5720538B2 - Storage device control device - Google Patents

Description

  The present invention relates to a control device for a power storage device mounted on a vehicle.

  In Patent Document 1, a battery deterioration state is detected, a battery target SOC is set high according to the deterioration state, and charge / discharge of the battery is controlled so that the battery SOC becomes the target SOC. Even when the deterioration state of the battery is in a predetermined state, a constant output and a traveling distance can be secured.

JP 2000-030753 A JP 2009-123435 A

  However, when charge / discharge control with a high target SOC is performed according to the deterioration state of the battery, a constant battery output can be ensured, but the battery SOC tends to be high. For this reason, for example, the capacity deterioration of the battery may be promoted by charging from a state in which the SOC is high, and it is not possible to suppress the battery life reduction.

A power storage device control device mounted on a hybrid vehicle according to a first aspect of the present invention includes a detection unit that detects a deterioration state based on an increase in resistance of the power storage device, and a controller that performs charge / discharge control of the power storage device. When a deterioration state is detected , the controller sets a target SOC based on relationship data that preliminarily defines a relationship between a decrease rate in which the increased resistance decreases with time and the SOC of the power storage device, and the power storage device The charge / discharge control is performed so that the target SOC is set from the target SOC before the deterioration state is detected by monitoring the SOC. At this time, a deterioration state that changes as the increased resistance decreases is detected by the detection unit, and the controller changes the target SOC based on the relationship data based on the change in the deterioration state that accompanies the decrease in the increased resistance. To do.

  According to the first invention of this application, since the SOC control center is controlled in accordance with the degree of increase in resistance (degree of deterioration), the SOC of the power storage device is maintained at a high level without maintaining the SOC higher than necessary. Therefore, the promotion of deterioration is suppressed, and the life of the power storage device can be improved.

  The detection unit detects the resistance of the power storage device after a lapse of a predetermined time from charge / discharge control centered on the first target SOC set based on the relational data, and the controller increases the resistance after the lapse of the predetermined time. The target SOC can be changed based on the amount of decrease and the expected amount of decrease based on the rate of decrease.

  Specifically, the controller continues the charge / discharge control without changing the first target SOC when the amount of decrease in the resistance that has increased after the predetermined time has elapsed is the same as the expected decrease, and after the predetermined time has elapsed, When the amount of decrease in the increased resistance is smaller than the expected amount of decrease, change to the second target SOC higher than the first target SOC, perform charge / discharge control so that the SOC of the power storage device becomes the second target SOC, When the amount of decrease in the increased resistance after the lapse of the predetermined time is larger than the expected amount of decrease, the resistance is changed to the third target SOC lower than the first target SOC, and the SOC of the power storage device is set to the third target SOC. Discharge control can be performed.

  For this reason, in charge / discharge control using the first target SOC set according to the rate of decrease of the increased resistance as the SOC control center, the decreased degree of the increased resistance (the degree of change in the deteriorated state) is detected, and the changed power storage Since the SOC control center is further changed according to the degree of increase in resistance of the device, it is possible to suppress the SOC from being kept higher than necessary, to suppress the deterioration of the power storage device, and to improve the life.

  The controller can calculate a reduction rate that reduces the increased resistance to the target value within a predetermined time, and can set the SOC corresponding to the reduction rate calculated based on the relationship data as the target SOC.

  The detection unit detects an internal resistance of the power storage device, and detects a deterioration state based on a resistance increase of the power storage device based on a difference between the detected internal resistance and a predetermined reference resistance value or a detected increase rate of the internal resistance. can do.

  The increase in resistance of the power storage device is due to an increase in internal resistance that occurs due to an uneven salt concentration in the electrolyte solution of the power storage device. As the power storage device, a lithium ion secondary battery can be used.

It is a block diagram of a hybrid vehicle. It is a figure which shows the structure of the battery mounted in a hybrid vehicle. It is an example which showed the relationship between the usage time of a battery, and the raise amount of battery resistance. It is a figure which shows the relationship between the recovery speed of a high rate resistance raise, and SOC. It is a flowchart which shows SOC control. It is a figure which shows an example of SOC control according to a high rate resistance raise. It is a figure which shows the recovery | restoration condition of the battery resistance which rose by the high rate resistance raise.

  Examples of the present invention will be described below.

Example 1
1 to 7 are diagrams showing the first embodiment. FIG. 1 is a block diagram showing the configuration of the plug-in hybrid vehicle of this embodiment. Although a plug-in hybrid vehicle will be described as an example, the controller 10 of the present embodiment can also be applied to a hybrid vehicle that does not have an external charging function from an external power source.

  As shown in FIG. 1, a plug-in hybrid vehicle 100 includes an engine 1, a first MG (Motor Generator) 2, a second MG 3, a power distribution mechanism 4, a transmission (such as a continuously variable transmission and a reduction gear) 5, and a battery 6. Installed.

  An output shaft of the engine 1 is connected to the power distribution mechanism 4. The power distribution mechanism 4 is connected to the input shaft of the transmission 5 and the input shaft of the first MG (power generation motor) 2. The output shaft of the transmission 5 is connected to a differential gear (differential device) 8 of the drive wheel 7, and the power of the engine 1 is transmitted to the drive wheel 7 via the power distribution mechanism 4. The output shaft of the transmission 5 is connected to the output shaft of a second MG (traveling motor) 3 so that the power of the second MG 3 is transmitted to the drive wheels 7 via the transmission 5.

  The power distribution mechanism 4 divides the power generated by the engine 1 into two paths, transmits the power generated by the engine 1 to the first MG 2, and transmits the power generated by the engine 1 to the first MG 2. And a second path for generating power. The power distribution mechanism 4 is controlled by a controller 10 which will be described later. The controller 10 is transmitted to each of the first and second paths in accordance with traveling control using the driving force of the engine 1 and charging control for the battery 6. Control power and ratio.

  The battery 6 (corresponding to a power storage device) is a power supply device that supplies power to the second MG 3, and the DC power of the battery 6 is converted into AC power by the inverter 9 and supplied to the second NG 3. The second MG 3 is an AC motor such as a three-phase synchronous motor or a three-phase induction motor.

  During regenerative braking of the plug-in hybrid vehicle 100, the second MG 3 is driven by the drive wheels 7 via the transmission 5, and the second MG 3 operates as a generator (generator). The second MG 3 is a driving source for driving the vehicle driven by the electric power supplied from the battery 7 and operates as a regenerative brake that converts braking energy into electric power. The electric power (regenerative energy) generated by the second MG 3 is an inverter. 9 is stored in the battery 6 through 9.

  The first MG 2 is a generator that generates electric power by being rotationally driven by the power of the engine 1 and supplies electric power generated through the inverter 9 to the battery 6. The first MG2 can be configured by an AC motor such as a three-phase synchronous motor or a three-phase induction motor, similarly to the second MG3.

  The engine 1 is an internal combustion engine. Exhaust gas discharged from the engine 1 is exhausted outside the vehicle through a catalyst (not shown) (for example, a three-way catalyst).

  Further, the electric power generated by the first MG 2 can be supplied as the electric power for driving the second MG 3 as it is, or can be supplied as the electric power stored in the battery 6. For example, the second MG 3 is controlled according to the SOC state of the battery 6 or the vehicle situation, and is driven by one or both of the electric power stored in the battery 6 and the electric power generated by the first MG 2.

  The controller 10 is a control device for the plug-in hybrid vehicle 100, calculates a required vehicle output required for the entire plug-in hybrid vehicle 100, and controls output of the engine 1 and the battery 6 based on the required vehicle output.

  The controller 10 functions as an engine control device that controls the engine 1 and a motor control device that controls the first MG2 and the second MG3, and also manages the charge / discharge control of the battery 6 and the SOC and deterioration state of the battery 6. Function as.

  The controller 10 selects a driving supply source according to the driving state, and performs vehicle travel control using driving force from one or both of the engine 1 and the second MG 3. For example, when the accelerator opening is small or the vehicle speed is low, the driving force from the engine 1 is not used (with the engine 1 stopped), and only the second MG 120 is used as the driving source. Run control. Note that even in the case of travel control of a plug-in hybrid vehicle using only the second MG 120 as a drive source, the engine 1 can be driven and power generation control by the first MG 2 can be performed.

  On the other hand, when the accelerator opening is large, when the vehicle speed is high, or when the SOC (State Of Charge) of the battery 6 is small, traveling control using the engine 1 as a drive source is performed. At this time, the controller 10 can perform travel control of the plug-in hybrid vehicle using only the engine 1 or both the engine 1 and the second MG 3 as drive sources.

  The plug-in hybrid vehicle 100 according to the present embodiment includes an external charging unit that charges the battery 6 with power supplied from the external power source 200. An inlet 12 is provided at a side portion of the plug-in hybrid vehicle 100, and a charging cable 220 having a connection plug 210 that connects the plug-in hybrid vehicle 100 and the external power source 200 is connected. The external power source 200 includes a household power source and a charging stand.

  The controller 10 can function as a power supply control device that performs external charging control via external charging means. When it is detected that the connection plug 210 extending from the external power source 200 is connected to the inlet 12 (a signal indicating that the connection plug 210 and the inlet 12 output from the inlet 12 or the connection plug 210 are connected). When receiving), the battery 11 is charged with the electric power supplied from the external power source 200 by controlling the charger 11 provided between the inlet 12 and the battery 6.

  The charger 11 is connected between the inlet 12 and the battery 6 and includes an AC / DC converter, a booster, and the like that convert AC power supplied from the external power source 200 into DC power. The charger 11 operates based on a drive signal output from the controller 10.

  The external power source 200 can include the charger 11. That is, when the external power source 200 includes the charger 11, the plug-in hybrid vehicle 100 may not include the charger 11.

  The controller 10 may have a system configuration in which each function as an engine control device, a motor control device, a battery control device, and a power supply control device is configured by an individual control device.

  FIG. 2 is a diagram illustrating a configuration of a battery system including the battery 6 mounted on the plug-in hybrid vehicle 100.

  The battery 6 is an assembled battery having a plurality of single cells 6a connected in series. As the single battery 6a (storage element), a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery. The number of single cells 6a constituting the battery 6 can be appropriately set based on the required output. The battery 6 may include a plurality of single cells 6a connected in parallel. The unit cell 6a includes a power generation element (for example, a positive electrode body, a negative electrode body, a positive electrode body, and a separator (including an electrolytic solution) disposed between the negative electrode bodies can be stacked). It consists of

  The battery 6 is provided with a voltage monitoring IC 20, a current sensor 21 and a temperature sensor 22. Each of the voltage monitoring IC 20, the current sensor 21 and the temperature sensor 22 is connected to the controller 10 and outputs a detection result to the controller 10. The voltage monitoring IC 20 detects the inter-terminal voltage of the battery 6 and the inter-terminal voltage of each unit cell 6 a that constitutes the battery 6. The current sensor 21 detects the charging / discharging current of the battery 6 that performs charging / discharging. The temperature sensor 22 detects the temperature of the battery 6. The temperature sensor 22 can be configured to be included in the voltage monitoring IC 20, for example, can be configured as a monitoring IC that detects the voltage and temperature of the battery 6.

  Next, SOC control of the battery 6 of the present embodiment will be described. As described above, the controller 10 automatically selects a drive source according to the driving state, and performs vehicle travel control using the drive force from one or both of the engine 1 and the second MG 3.

  The controller 10 monitors the SOC while the vehicle is traveling, and uses the engine 1 and the second MG 3 to control traveling so as to travel while maintaining the SOC of the battery 6 within a predetermined target value or within a predetermined range around the target value. It can be performed. For example, vehicle control using the driving force of the engine 1 and / or the driving force of the second MG 3 (the power of the battery 6) is performed so that the electric power (SOC) stored in the battery 6 does not become lower than a predetermined target value. When the SOC is lower than the target value, the controller 10 starts the engine 1 and performs charging control by the first MG 2, while increasing the SOC lower than the target value so as to approach the target value, the engine 1 And / or the driving force of the second MG 3 (the power of the battery 6) is used to perform the traveling control. On the other hand, when the SOC is higher than the target value, the controller 10 performs traveling control mainly using the driving force of the second MG 3 (power of the battery 6), and sets the SOC that is higher than the target value as the target value. It can be controlled to decrease so as to approach. The controller 10 performs charge / discharge control on the battery 6 with the target value as the SOC control center.

  Here, the SOC (State of Charge) indicates the ratio of the current charge capacity to the full charge capacity of the battery 6. The controller 10 performs processing for calculating or specifying the SOC of the battery 6 using the detection value of the voltage monitoring IC 20 or the current sensor 21, and stores and manages the charge / discharge history and the SOC information in a storage unit (not shown). In addition, the SOC information of each single cell 6a constituting the battery 6 can be managed.

  The SOC of the battery 6 can be specified from the OCV (Open Circuit Voltage) of the battery 6. Since SOC and OCV are in a correspondence relationship, if this correspondence relationship is obtained in advance, the SOC can be specified from the OCV. The OCV of the battery 6 can be calculated from the CCV (terminal voltage: Closed Circuit Voltage) of the battery 6 detected by the voltage monitoring IC 20. On the other hand, the SOC of the battery pack 10 can be calculated by detecting the charging / discharging current of the battery 6 using the current sensor 21 and integrating the current values when charging / discharging the battery 6.

  Next, the high rate resistance increase and the SOC control of the battery 6 according to the present embodiment will be described. The deterioration state of the battery 6 (secondary battery) that performs charging / discharging includes a deterioration component that occurs due to wear of the battery 6 and a deterioration component (high-rate deterioration component) that occurs due to an uneven salt concentration in the battery 6. ing.

  When the deterioration occurs due to the uneven salt concentration in the battery 6, the battery resistance increases. For example, a decrease in the electrolyte salt concentration in the positive electrode during discharge causes an increase in reaction resistance, and a decrease in the electrolyte salt concentration in the negative electrode during charging also increases the reaction resistance. Is expressed.

  FIG. 3 is an example showing the relationship between the usage time of the battery 6 and the amount of increase in battery resistance. The battery 6 has an initial resistance, and the amount of wear deterioration increases due to charging / discharging of the battery 6. Further, the amount of increase in the high-rate resistance changes due to charging / discharging of the battery 6. The amount of increase in resistance of the secondary battery is the sum of the amount of wear deterioration and the amount of increase in high-rate resistance.

  The occurrence of the high rate deterioration component can be detected by monitoring the increase in battery resistance. For example, the battery resistance of the battery 6 is obtained by dividing the difference between the OCV of the battery 6 and the voltage (CCV) at the time of charging / discharging by the charging / discharging current. By subtracting the battery resistance (corresponding to the reference resistance value) due to wear deterioration), it is possible to calculate the resistance increase amount (high rate resistance increase amount) due to the high rate deterioration component. If the high rate resistance increase amount exceeds a predetermined value, it can be detected that the high rate resistance increase has occurred.

  In addition, the occurrence of a high rate deterioration component can be detected using the high rate resistance increase rate. For example, an allowable value is set, and when the high rate resistance increase rate exceeds the allowable value, it can be determined that a high rate resistance increase has occurred. The allowable value can be set based on the amount of increase in the high-rate resistance and the battery resistance when no increase in the high-rate resistance occurs.

  On the other hand, since the high-rate deterioration component is generated due to the salt concentration unevenness in the battery 6, the resistance increased by the high-rate deterioration component is recovered by eliminating the salt concentration unevenness, and the battery resistance not including the high-rate deterioration component is recovered. It has been known.

  FIG. 4 is a diagram showing the relationship between the recovery amount of the increase in the high-rate resistance per unit time and the SOC of the battery 6. FIG. 4 shows a recovery rate of high-rate resistance increase (resistance decrease) by measuring the degree of recovery of resistance increased by the high-rate degradation component and its time in advance, and calculating a decrease amount (recovery amount) of increased resistance per unit time. The rate is a recovery speed map representing the relationship with the SOC of the battery 6.

  As shown in FIG. 4, the higher the SOC of the battery 6 is, the higher the recovery speed, which is the resistance reduction rate, and the lower the SOC is, the lower the recovery speed is. The recovery speed map is configured to be held in advance by the controller 10.

  In the present embodiment, for example, in the charge / discharge control of the battery 6 during traveling of the vehicle, when the high rate resistance increase is detected, and the high rate resistance increase is detected, the first target SOC corresponding to the recovery rate of the high rate resistance increase is detected. The charge / discharge control is performed with the first target SOC determined according to the recovery rate of the high rate resistance increase from the target SOC before the high rate resistance increase is detected (normal target SOC) as the SOC control center. To do.

  Further, in charge / discharge control using the first target SOC determined according to the recovery rate of the high-rate resistance increase as the SOC control center, the recovery rate (change degree of deterioration) of the high-rate resistance increase is detected, and the high-rate resistance increase Depending on the degree of recovery, the SOC control center is changed to a second target SOC different from the first target SOC, and charge / discharge control is performed so as to eliminate the generated high rate deterioration component.

  With reference to FIG. 5 to FIG. 7, an operation flow of charge / discharge control during traveling of the vehicle according to the present embodiment will be described. FIG. 5 is a flowchart of the SOC control according to the increase in the high-rate resistance by the controller 10. FIG. 6 is a diagram showing the transition of the SOC control center according to the increase in the high-rate resistance. FIG. 7 is a diagram illustrating a recovery state of the battery resistance that has increased due to the increase in the high-rate resistance.

  As shown in FIG. 6, the controller 10 performs charge / discharge control on the battery 6 while the vehicle is traveling, with a predetermined SOC (target SOC at normal time) as the SOC control center until a high-rate deterioration component is detected. The controller 10 performs high-rate resistance increase detection at predetermined timings during travel control during travel of the vehicle. In step S101, the controller 10 calculates the battery resistance of the battery 6 based on the detection values detected by the voltage monitoring IC 20 and the current sensor 21.

  In Step S102, the controller 10 obtains a high rate resistance increase amount by subtracting the wear deterioration amount not including the high rate deterioration component from the calculated battery resistance, and when the calculated high rate resistance increase amount exceeds a predetermined value, It is detected that a high-rate resistance rise has occurred. In the example of FIG. 6, the occurrence of a high-rate resistance increase is detected at time t1.

When the controller 10 detects the occurrence of the high-rate resistance increase in step S102, the controller 10 proceeds to step S103, and acquires the first target SOC corresponding to the recovery speed from the recovery speed map shown in FIG . The controller 10 calculates a recovery amount (recovery speed) per unit time from the high rate resistance increase amount and the recovery target time based on a preset recovery target time of the high rate resistance increase. The controller 10 determines the first target SOC corresponding to the increase in the high-rate resistance corresponding to the calculated recovery speed from the recovery speed map shown in FIG.

  For example, if the battery resistance increases by 20% due to the increase in the high-rate resistance from the state where the battery resistance before the increase in the high-rate resistance is detected to 1.5 mΩ, the resistance increases by 0.3 mΩ. The value is recovered at the recovery target time. When the recovery target time is set to 10 minutes, the rate of decrease that reduces the battery resistance to 1.50 mΩ, which is the target value in 10 minutes, that is, the recovery speed that recovers the increased resistance value of 0.3 mΩ, It can be calculated as 0.03 [mΩ / min]. The SOC corresponding to the recovery speed 0.03 can be obtained from the recovery speed map. The recovery target time can be arbitrarily set, and can be a relatively short time of several minutes or several tens of minutes, for example.

  In step S103, the controller 10 sets the first target SOC corresponding to the increase in the high-rate resistance acquired from the recovery speed map as the SOC control center. After the target SOC is set, the controller 10 performs charge / discharge control using the determined first target SOC as the SOC control center (S104). In the example of FIG. 6, charge / discharge control is performed by raising the SOC control center from the normal target SOC to the first target SOC (first target SOC> normal target SOC).

  The controller 10 uses the engine 1 and the second MG 3 so that when the current SOC control center is pulled up or pulled down, the SOC of the battery 6 runs while maintaining each SOC control center after the change. And run control. The controller 10 starts the engine 1, performs charge control by the first MG 2, and raises the SOC of the battery 6 so as to approach the raised SOC control center, while driving the engine 1 or / and the second MG 3. The travel control using (electric power of the battery 6) is performed, or the travel control mainly using the driving force of the second MG 3 (power of the battery 6) is performed, and the SOC of the battery 6 is lowered to the center of the SOC control. The driving control using the driving force of the engine 1 and / or the driving force of the second MG 3 (electric power of the battery 6) is performed while decreasing the distance so as to approach.

  Subsequently, the controller 10 detects the battery resistance of the battery 6 and detects the amount of increase in the high rate resistance after a predetermined time has elapsed after the start of charge / discharge control with the first target SOC corresponding to the increase in the high rate resistance as the SOC control center. The recovery status, that is, the degree of change in the deterioration degree is confirmed, and charge / discharge control is performed in which the SOC control center is further changed in accordance with the degree of change in the deterioration degree.

  For example, in the example of FIG. 6, at the time t2 after the elapse of a predetermined time from the time t1 when the charge / discharge control with the first target SOC corresponding to the increase in the high rate resistance as the SOC control center is started, the controller 10 6 battery resistance is detected (S105). The battery resistance of the battery 6 can be detected in the same manner as in step S101.

  Based on the battery resistance detected in step S105, the controller 10 confirms the recovery status of the high rate resistance increase (S106). In step S106, the controller 10 detects how much the increased resistance value at the time when the high-rate resistance increase is detected is lower at the time t2. Specifically, since the transition of the estimated (predicted) decrease in the resistance value can be calculated from the recovery speed corresponding to the first target SOC and the recovery target time, the battery resistance at the time t2 is By determining whether or not there is a deviation from the estimated decrease in the resistance value, it is possible to confirm the degree of recovery of the resistance value of the battery 6 that has increased due to the increase in the high-rate resistance.

  As shown in FIG. 7, in step S106, the controller 10 determines that the battery resistance value of the battery 6 detected at time t2 is within a predetermined range of the spinal resistance value corresponding to the recovery speed indicated by the dotted line. It is determined whether or not there is. When it is determined that the recovered battery resistance value at the time t2 is within the range of the estimated resistance value according to the recovery speed (the state shown in FIG. 6 and FIG. 7A), the controller 10 proceeds to step S107. The process proceeds to step S110 without changing the SOC control center, and the charge / discharge control using the first target SOC as the SOC control center is continued. For example, if the estimated resistance value at time t2 after the elapse of a predetermined time from time t1 is 1.65 mΩ, if the battery resistance value of the battery 6 detected at time t2 is 1.65 mΩ, the controller 10 The SOC control center is not changed.

  When it is determined that the battery resistance value of the battery 6 detected at the time t2 is smaller than the estimated resistance value corresponding to the recovery speed (the state shown in FIG. 6 and FIG. 7B), the controller 10 Since the battery resistance recovery is slower than the estimated resistance value in S108, the second target SOC higher than the first target SOC is set to the SOC control center based on the recovery speed map shown in FIG. 4 in order to increase the recovery speed. Set to. For example, if the increased resistance value at the time when the high-rate resistance increase is detected is 1.8 mΩ, and the estimated resistance value at the time t2 after a predetermined time has elapsed is 1.65 mΩ, the battery detected at the time t2 If the battery resistance value of 6 is 1.7 mΩ, the resistance value that has risen within the recovery target time does not decrease, so the controller 10 raises the SOC control center to a second target SOC that is higher than the first target SOC.

  For example, when the time t2 is a time when 5 minutes have elapsed from the time t1, the recovery speed for recovering the battery resistance value 1.7 mΩ of the battery 6 to 1.5 mΩ in the remaining 5 minutes is 0.04. The controller 10 acquires the SOC corresponding to the recovery speed 0.04 from the recovery speed map, and sets the second target SOC acquired from the recovery speed map corresponding to the recovery speed 0.04 as the SOC control center. Thus, when the recovery of the battery resistance is slower than the estimated resistance value, the controller 10 raises the SOC control center to the second target SOC higher than the first target SOC so as to increase the recovery speed (second target SOC> First target SOC). The controller 10 proceeds to step S110 and performs charge / discharge control with the second target SOC as the SOC control center.

  When it is determined that the battery resistance value of the battery 6 detected at the time t2 is larger than the estimated resistance value corresponding to the recovery speed (the state shown in FIG. 6 and FIG. 7C), the process proceeds to step S109. Since the battery resistance recovers faster than the estimated resistance value, a third target SOC lower than the first target SOC is set at the SOC control center based on the recovery speed map shown in FIG. 4 in order to reduce the recovery speed. For example, if the increased resistance value at the time when the high-rate resistance increase is detected is 1.8 mΩ, and the estimated resistance value at the time t2 after a predetermined time has elapsed is 1.65 mΩ, the battery detected at the time t2 If the battery resistance value of No. 6 is 1.60 mΩ, the resistance value that has risen earlier than the recovery target time is reduced to the target resistance value, so the controller 10 performs SOC control to a third target SOC that is lower than the first target SOC. Lower the center.

  For example, when the time t2 is a time when 5 minutes have elapsed from the time t1, the recovery speed for recovering the battery resistance value 1.60 mΩ of the battery 6 to 1.5 mΩ in the remaining 5 minutes is 0.02. The controller 10 acquires the SOC corresponding to the recovery speed 0.02 from the recovery speed map, and sets the third target SOC acquired from the recovery speed map corresponding to the recovery speed 0.02 as the SOC control center. As described above, when the battery resistance recovers faster than the estimated resistance value, the controller 10 lowers the SOC control center to the third target SOC lower than the first target SOC so that the recovery speed is slow (first target SOC> Third target SOC). The controller 10 proceeds to step S110 and performs charge / discharge control with the third target SOC as the SOC control center.

  The controller 10 calculates the battery resistance of the battery 6 again in step S111 after elapse of a predetermined time from the charge / discharge control in which the recovery speed is changed according to the degree of recovery of the increased battery resistance in step S110, and a high-rate resistance increase occurs. It is determined whether or not the resistance value of the battery 6 has recovered to the target resistance value reached in the recovery target time (S112). When it is determined that the controller 10 has not recovered to the target resistance value, the controller 10 returns to step S106 and confirms the recovery state of the battery resistance according to the recovery speed corresponding to the target SOC changed or maintained in steps S107 to S109. Then, the target SOC is set according to the recovery speed according to the degree of recovery, and charge / discharge control is performed with the set target SOC as the SOC control center (from step S106 to step S111).

  In step S112, when it is determined that the increased resistance value of the battery 6 in which the high-rate resistance increase has occurred has recovered to the target resistance value, the controller 10 proceeds to step S113, and sets the target SOC corresponding to the high-rate resistance increase. The charge / discharge control with the SOC control center is terminated, the control is switched to the control with the target SOC at the normal time where no increase in the high-rate resistance has occurred as the control center (the SOC control center is set as the target SOC at the normal time), and the charge / discharge control is performed. Continue discharge control. As shown in the example of FIG. 6, the charge / discharge control at the SOC control center according to the increase in leaf high-rate resistance is terminated with the cancellation of the increase in high-rate resistance at time t3, and thereafter the target according to the increase in high-rate resistance is reached. Charge / discharge control in which the SOC control center is shifted to the target SOC at the normal time lower than the SOC is performed.

  As described above, in this embodiment, when an increase in the high-rate resistance is detected, the SOC control center is changed to the target SOC corresponding to the recovery rate of the increase in the high-rate resistance, and the deterioration of the battery 6 due to the increase in the high-rate resistance is solved. When the deterioration of the battery 6 due to the increase in the high-rate resistance is eliminated, the SOC control center is changed to the normal target SOC.

  For this reason, the SOC control center is controlled in accordance with the increase degree (deterioration degree) of the battery resistance, and it is not necessary to maintain the SOC higher than necessary with respect to the generated battery resistance. After the occurrence of deterioration) has been resolved, that is, as the degree of increase in battery resistance has changed to 0, the SOC control center is changed to the normal low target SOC, so that the SOC becomes high. Since it can reduce, the deterioration promotion of the battery 6 is suppressed and the lifetime of the battery 6 can be improved.

  In particular, in the present embodiment, in charge / discharge control with the first target SOC determined according to the recovery rate of the high-rate resistance increase as the SOC control center, the recovery degree of the high-rate resistance increase (the degree of change in the deterioration level) is detected. Further, the SOC control center is further changed according to the recovery rate of the increase in the high-rate resistance, and charge / discharge control is performed so as to eliminate the generated high-rate deterioration component. For this reason, it is suppressed that SOC is maintained in a state higher than necessary, deterioration promotion of the battery 6 can be suppressed, and the life of the battery 6 can be improved.

1 Engine 2 1st MG
3 Second MG
4 Power Distribution Mechanism 5 Transmission 6 Battery 7 Drive Wheel 8 Differential 9 Inverter 10 Controller 11 Charger 12 Inlet 100 Plug-in Hybrid Vehicle 200 External Power Supply 210 Connection Plug 220 Charging Cable

Claims (7)

A control device for a power storage device mounted on a hybrid vehicle,
A detection unit for detecting a deterioration state based on an increase in resistance of the power storage device;
When the deterioration state is detected, a target SOC is set based on relationship data that preliminarily defines a relationship between a decrease rate in which the increased resistance decreases with time and the SOC of the power storage device, and the power storage A controller that performs charge / discharge control of the power storage device such that the SOC of the device is monitored to achieve the set target SOC from the target SOC before the deterioration state is detected ,
The detection unit detects a deterioration state that changes as the increased resistance decreases,
The controller is configured to change a target SOC based on the relational data based on a change in a deterioration state associated with a decrease in the increased resistance. The detection unit detects the resistance of the power storage device after a predetermined time has elapsed from charge / discharge control centered on the first target SOC set based on the relationship data,
2. The power storage device according to claim 1, wherein the controller changes the target SOC based on a decrease amount of the increased resistance after the lapse of the predetermined time and an expected decrease amount based on the decrease rate. Control device. The controller is
When the amount of decrease in the increased resistance after the lapse of the predetermined time is the same as the expected amount of decrease, the charge / discharge control is continued without changing the first target SOC,
When the amount of decrease in the increased resistance after the lapse of the predetermined time is smaller than the expected decrease amount, it is changed to a second target SOC higher than the first target SOC, and the SOC of the power storage device is changed to the second target SOC. The charge / discharge control is performed so as to be SOC,
When the amount of decrease in the increased resistance after the lapse of the predetermined time is larger than the expected amount of decrease, the SOC is changed to a third target SOC lower than the first target SOC, and the SOC of the power storage device is changed to the third target SOC. The power storage device control device according to claim 2, wherein the charge / discharge control is performed so as to be an SOC.   The controller calculates a reduction rate for reducing the increased resistance to a target value within a predetermined time, and sets an SOC corresponding to the calculated reduction rate as the target SOC based on the relationship data. The power storage device control device according to any one of claims 1 to 3, wherein the power storage device control device is characterized.   The detection unit detects an internal resistance of the power storage device, and increases the resistance of the power storage device based on a difference between the detected internal resistance and a predetermined reference resistance value or an increase rate of the detected internal resistance. 5. The storage device control device according to claim 1, wherein the deterioration state is detected.   6. The power storage device according to claim 1, wherein the increase in resistance of the power storage device is an increase in internal resistance caused by an uneven salt concentration in an electrolyte solution of the power storage device. Control device. The power storage device control device according to any one of claims 1 to 6, wherein the power storage device is a lithium ion secondary battery.

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