JP5838840B2 - Battery system - Google Patents

Description

  The present invention relates to a battery system that controls charging / discharging of each assembled battery when a vehicle is driven using two assembled batteries.

  In the technique described in Patent Document 1, in a vehicle equipped with a large-capacity power storage device and a large-output power storage device, the large-capacity power storage device is mainly discharged until the predetermined condition is satisfied, and after the predetermined condition is satisfied, At least the large output power storage device is discharged. Here, the temperature of the large-capacity power storage device is used as a parameter for determining the predetermined condition.

JP 2011-030308 A JP 2011-041461 A

  In Patent Document 1, a large-capacity power storage device and a large-output power storage device are selectively used in consideration of deterioration of the large-capacity power storage device due to temperature. Here, the power storage device may deteriorate due to factors other than temperature. Specifically, when the power storage device is discharged, a salt concentration distribution may be generated to cause deterioration.

A battery system according to the present invention includes a motor generator that is a drive source for running a vehicle, a first assembled battery and a second assembled battery that are connected in parallel to the motor generator and supply power to the motor generator, And a controller for controlling charging / discharging of the assembled battery and the second assembled battery. When the first assembled battery and the second assembled battery supply power to the motor generator, the output power of the second assembled battery is higher than the output power of the first assembled battery. The controller, in the second assembled battery, when the deterioration due to the salt concentration distribution during discharge is generated by using the output power of the first assembled battery, charging the second assembled battery. Further, the controller discharges the first assembled battery so as to satisfy the required power supplied to the motor generator.

According to the present invention, when deterioration due to the salt concentration distribution occurs by discharging the second assembled battery, it becomes easy to eliminate the deterioration due to the salt concentration distribution by charging the second assembled battery. Here, since the first assembled battery and the second assembled battery are connected in parallel, the output power of the first assembled battery can be used as the charging power of the second assembled battery . In the present invention, since the required power supplied to the motor generator is secured by discharging the first assembled battery, the running performance of the vehicle can be secured.

It is a figure which shows the structure of a battery system. It is a figure which shows charge and discharge of an assembled battery. It is a figure which shows the relationship between the capacity maintenance rate of an assembled battery, and the square root of time. It is a flowchart which shows charge / discharge control of an assembled battery. It is a figure which shows the electric power change in charging / discharging control of a 1st assembled battery and a 2nd assembled battery. It is a figure which shows the electric power change in charging / discharging control of a 1st assembled battery and a 2nd assembled battery.

  Examples of the present invention will be described below.

  A battery system that is Embodiment 1 of the present invention will be described. FIG. 1 is a diagram illustrating a configuration of a battery system according to the present embodiment. The battery system of the present embodiment is mounted on a vehicle. Such vehicles include electric vehicles and hybrid vehicles. The electric vehicle includes only an assembled battery described later as a power source for running the vehicle. The hybrid vehicle includes an engine or a fuel cell as a power source for running the vehicle in addition to the assembled battery described later.

  The first assembled battery 10 includes a plurality of single cells 11 connected in series. A fuse 12 is connected to two unit cells 11 included in the first assembled battery 10. The second assembled battery 20 has a plurality of single cells 21 connected in series. A fuse 22 is connected to two unit cells 21 included in the second assembled battery 20. The fuses 12 and 22 are used to suppress excessive current from flowing through the assembled batteries 10 and 20.

  As the cells 11 and 21, secondary batteries such as nickel metal hydride batteries and lithium ion batteries can be used. In FIG. 1, the plurality of single cells 11 and 21 constituting the assembled batteries 10 and 20 are connected in series, but the assembled batteries 10 and 20 include a plurality of single cells 11 and 21 connected in parallel. It may be.

  As the first assembled battery 10, for example, an assembled battery having an energy capacity larger than that of the second assembled battery 20 can be used. Specifically, the power capacity density of the single cells 11 constituting the first assembled battery 10 can be made higher than the power capacity density of the single cells 21 constituting the second assembled battery 20. The power capacity density of the cells 11 and 21 is, for example, the capacity per unit mass of the cells 11 and 21 (unit [Wh / kg]) or the capacity per unit volume of the cells 11 and 21 (unit [Wh / kg]). L]).

  Further, as the second assembled battery 20, an assembled battery that charges and discharges with a larger current than the first assembled battery 10 can be used. Specifically, the output density of the unit cells 21 constituting the second assembled battery 20 can be made higher than the output density of the unit cells 11 constituting the first assembled battery 10. The output density of the cells 11 and 21 is, for example, the power per unit mass of the cells 11 and 21 (unit [W / kg]) or the power per unit volume of the cells 11 and 21 (unit [W / L]). ]).

  The voltage sensor 13 detects the voltage between the terminals of the first assembled battery 10 and outputs the detection result to the controller 100. The current sensor 14 detects the charge / discharge current of the first assembled battery 10 and outputs the detection result to the controller 100. The voltage sensor 23 detects the voltage between the terminals of the second assembled battery 20 and outputs the detection result to the controller 100. The current sensor 24 detects the charge / discharge current of the second assembled battery 20 and outputs the detection result to the controller 100.

  First assembled battery 10 is connected to boost converter 30 via positive electrode line PL1 and negative electrode line NL1. Capacitor 16 is connected to positive electrode line PL1 and negative electrode line NL1, and smoothes voltage fluctuation between positive electrode line PL1 and negative electrode line NL1.

  A system main relay SMR-G1 is provided in the positive electrode line PL1, and a system main relay SMR-B1 is provided in the negative electrode line NL1. System main relay SMR-P1 and current limiting resistor 15 are connected in series to each other, and are connected in parallel to system main relay SMR-G1. The current limiting resistor 15 is used for suppressing the inrush current from flowing when the first assembled battery 10 is connected to the boost converter 30.

  System main relays SMR-G1, SMR-P1, and SMR-B1 are switched between ON and OFF in response to a control signal from controller 100. When connecting the first assembled battery 10 to the boost converter 30, first, the controller 100 switches the system main relays SMR-P1 and SMR-B1 from off to on. At this time, a current flows through the current limiting resistor 15. Next, the controller 100 switches the system main relay SMR-G1 from off to on and switches the system main relay SMR-P1 from on to off.

  Thereby, the connection between the first assembled battery 10 and the boost converter 30 is completed. When the connection between the first assembled battery 10 and the boost converter 30 is cut off, the controller 100 switches the system main relays SMR-G1 and SMR-B1 from on to off.

  Second assembled battery 20 is connected to inverter 40 via positive electrode line PL2 and negative electrode line NL2. A system main relay SMR-G2 is provided in the positive line PL2, and a system main relay SMR-B2 is provided in the negative line NL2. System main relay SMR-P2 and current limiting resistor 25 are connected in series to each other, and are connected in parallel to system main relay SMR-G2.

  System main relays SMR-G2, SMR-P2, and SMR-B2 are switched between on and off in response to a control signal from controller 100. When connecting the second assembled battery 20 to the inverter 40 (in other words, bus lines PB and NB described later), the controller 100 first switches the system main relays SMR-P2 and SMR-B2 from off to on. At this time, a current flows through the current limiting resistor 25. Next, the controller 100 switches the system main relay SMR-G2 from off to on and switches the system main relay SMR-P2 from on to off.

  Thereby, the connection between the second assembled battery 20 and the inverter 40 (bus lines PB, NB) is completed. When the connection between the second assembled battery 20 and the inverter 40 (bus lines PB, NB) is cut off, the controller 100 switches the system main relays SMR-G2, SMR-B2 from on to off. By connecting the second assembled battery 20 to the bus lines PB and NB, the power of the first assembled battery 10 can be supplied to the second assembled battery 20. That is, the second assembled battery 20 can be charged using the output power of the first assembled battery 10.

  Boost converter 30 boosts the voltage between positive line PL1 and negative line NL1, and outputs the boosted voltage between bus lines PB and NB. Boost converter 30 has a reactor 31. One end of reactor 31 is connected to positive electrode line PL <b> 1, and the other end of reactor 31 is connected to the emitter of transistor 32 and the collector of transistor 33.

  The transistors 32 and 33 are connected in series between the bus lines PB and NB. Here, the collector of the transistor 32 is connected to the bus line PB, and the emitter of the transistor 33 is connected to the bus line NB. The emitter of the transistor 32 is connected to the collector of the transistor 33. As the transistors 32 and 33, for example, an IGBT (Insulated Gate Bipolar Transistor), an npn transistor, or a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) can be used.

  The diodes 34 and 35 are connected in parallel to the transistors 32 and 33, respectively. Specifically, the anodes of the diodes 34 and 35 are connected to the emitters of the transistors 32 and 33, and the cathodes of the diodes 34 and 35 are connected to the collectors of the transistors 32 and 33. The capacitor 17 is connected to the bus lines PB and NB, and smoothes voltage fluctuations between the bus lines PB and NB.

  The step-up converter 30 can perform a step-up operation or a step-down operation. When the boost converter 30 performs a boost operation, the controller 100 turns on the transistor 33 and turns off the transistor 32. Thereby, a current flows from the first assembled battery 10 to the reactor 31, and magnetic energy corresponding to the amount of current is accumulated in the reactor 31. Next, the controller 100 causes the current to flow from the reactor 31 to the inverter 40 via the diode 34 by switching the transistor 33 from on to off. As a result, the energy accumulated in reactor 31 is released from boost converter 30 and the boost operation is performed.

  When boost converter 30 performs a step-down operation, controller 100 turns on transistor 32 and turns off transistor 33. Thereby, the electric power from the inverter 40 is supplied to the 1st assembled battery 10, and the 1st assembled battery 10 is charged.

  Inverter 40 converts DC power supplied from boost converter 30 or second assembled battery 20 into AC power and outputs the AC power to motor generator (MG) 50. Further, the inverter 40 converts AC power generated by the motor generator 50 into DC power and outputs the DC power to the boost converter 30 and the second assembled battery 20. Inverter 40 operates in response to a control signal from controller 100. As motor generator 50, a three-phase AC motor can be used.

  Motor generator 50 converts electrical energy (AC power) supplied from inverter 40 into kinetic energy. Motor generator 50 is connected to wheels, and kinetic energy (rotational force) generated by motor generator 50 is transmitted to the wheels. Thereby, the vehicle can be driven. Further, when the vehicle is decelerated or stopped, the motor generator 50 receives the rotational force from the wheels and generates electric power. The AC power generated by the motor generator 50 is output to the inverter 40.

  The controller 100 has a memory 101 and a timer 102. The memory 101 stores a program for operating the controller 100 and various information. The timer 102 is used to measure the discharge time of the assembled batteries 10 and 20 as will be described later. Note that the memory 101 and the timer 102 can be provided outside the controller 100.

  In the battery system of the present embodiment, the vehicle can be driven using the outputs of the first assembled battery 10 and the second assembled battery 20. For example, as the power for running the vehicle, the output power of the second assembled battery 20 can be mainly used, and the output power of the first assembled battery 10 can be used supplementarily. The first assembled battery 10 and the second assembled battery 20 are repeatedly discharged and charged, for example, as shown in FIG. 2 according to the traveling pattern of the vehicle. In FIG. 2, the vertical axis represents the current value, and the horizontal axis represents time. Here, the current value when discharging the assembled batteries 10 and 20 is a positive value, and the current value when charging the assembled batteries 10 and 20 is a negative value.

  As the battery packs 10 and 20 continue to be discharged, in other words, as the discharge time t_dc shown in FIG. 2 becomes longer, the battery packs 10 and 20 are likely to deteriorate. If the discharge of the assembled batteries 10 and 20 is continued at a discharge rate equal to or higher than a predetermined value, polarization (salt concentration distribution) occurs, and the internal resistance of the assembled batteries 10 and 20 tends to increase.

  In addition, when a lithium ion secondary battery is used as the unit cells 11 and 21, lithium may be deposited due to a salt concentration distribution, and the capacity of the unit cells 11 and 21 (the assembled batteries 10 and 20) is increased by the deposition of lithium. Will fall. Here, as shown in FIG. 3, as the discharge time t_dc becomes longer, the capacity maintenance rate of the assembled batteries 10 and 20 tends to decrease. The capacity retention rate may be proportional to the square root of time, as shown in FIG.

  The capacity maintenance rate is a value obtained by dividing the full charge capacity of the current assembled battery 10, 20 by the full charge capacity of the assembled battery 10, 20 in the initial state. The initial state is a state in which the assembled batteries 10 and 20 are not deteriorated. For example, the initial state can be a state immediately after the assembled batteries 10 and 20 are manufactured. When the full charge capacity of the assembled batteries 10 and 20 is reduced, the capacity maintenance rate is lower than 1.

  Deterioration (increase in internal resistance and decrease in full charge capacity due to salt concentration distribution) due to continued discharge of the assembled batteries 10 and 20 can be eliminated by charging the assembled batteries 10 and 20. That is, by charging the assembled batteries 10 and 20, the salt concentration distribution generated by the discharge of the assembled batteries 10 and 20 can be easily eliminated. If the salt concentration distribution is eliminated, it is possible to suppress an increase in internal resistance and a decrease in full charge capacity.

  In this embodiment, when one of the assembled batteries 10 and 20 is deteriorated (deterioration due to the salt concentration distribution), the output of the other assembled battery is used to replace one of the assembled batteries. By charging, deterioration of one assembled battery is suppressed. This process will be described with reference to FIG. The process shown in FIG. 4 is executed by the controller 100.

  When the process shown in FIG. 4 is started, the second assembled battery 20 is mainly used rather than the first assembled battery 10, and the discharge power W2out_c of the second assembled battery 20 is the second as shown in FIGS. It is higher than the discharge power W1out_c of the battery pack 10. As shown in FIGS. 5 and 6, the power Wout when the assembled batteries 10 and 20 are discharged is a positive value, and the power Win when the assembled batteries 10 and 20 are charged is a negative value. .

  In step S <b> 101 of FIG. 4, the controller 100 uses the timer 102 to measure the discharge time t_dc of the second assembled battery 20. Here, the discharge time t_dc is a time when the second assembled battery 20 continues to be discharged. In addition, when the discharge of the second assembled battery 20 is intermittently performed, a time obtained by accumulating these discharge times can be set as a discharge time t_dc. In the present embodiment, as described above, the second assembled battery 20 is used more actively than the first assembled battery 10, and the output power W2out_c of the second assembled battery 20 is greater than the output power W1out_c of the first assembled battery 10. Therefore, the second assembled battery 20 is likely to be deteriorated due to the salt concentration distribution.

  In step S102, the controller 100 determines whether or not the discharge time t_dc acquired in step S101 is longer than the threshold value t_th. The threshold value t_th is a time until deterioration due to the salt concentration distribution occurs by continuing to discharge the second assembled battery 20. The threshold value t_th can be obtained in advance by an experiment or the like, and information regarding the threshold value t_th can be stored in the memory 101.

  When the discharge time t_dc is longer than the threshold value t_th, the controller 100 performs the process of step S103. When the discharge time t_dc is longer than the threshold value t_th, the controller 100 determines that the second assembled battery 20 has deteriorated due to the salt concentration distribution, and performs the process of step S103. On the other hand, when the discharge time t_dc is shorter than the threshold value t_th, the controller 100 performs the process of step S101.

  In this embodiment, the discharge time t_dc is compared with the threshold value t_th, but the present invention is not limited to this. In other words, in the second assembled battery 20, it is only necessary to suppress deterioration due to the salt concentration distribution. When deterioration due to the salt concentration distribution occurs, the internal resistance of the second assembled battery 20 tends to increase. For this reason, it is possible to calculate the internal resistance of the second assembled battery 20 and determine whether the calculated internal resistance (current internal resistance) is higher than a predetermined threshold.

  That is, when the current internal resistance is higher than the threshold value, it can be determined that the deterioration due to the salt concentration distribution has occurred. Here, the deterioration of the second assembled battery 20 (single battery 21) includes deterioration due to wear of the material constituting the single battery 21 (referred to as a wear deterioration component). Therefore, by removing the wear deterioration component from the current internal resistance, the deterioration component due to the salt concentration distribution can be specified. Since the wear deterioration component increases with the passage of time, the current wear deterioration component can be specified if the relationship between the wear deterioration component and the time is obtained in advance through experiments or the like.

  In step S103, the controller 100 determines whether or not a condition of the following formula (1) is satisfied.

  In the above formula (1), W1out_max represents the maximum output power of the first assembled battery 10, and the maximum output power W1out_max is an upper limit value when controlling the discharge of the first assembled battery 10. When controlling charging / discharging of the first assembled battery 10, an upper limit value corresponding to charging and discharging is set, and the first assembled battery 10 is set so that the charging power and discharging power of the first assembled battery 10 do not exceed the upper limit value. Charging / discharging is controlled. W1out_c indicates the current output power of the first assembled battery 10, and W2out_c indicates the current output power of the second assembled battery 20.

  W2in_req shown in the above equation (1) is electric power when charging the second assembled battery 20. In the present embodiment, since the second assembled battery 20 is charged using the output power of the first assembled battery 10, the power W2in_req is the first assembled battery 10 used for charging the second assembled battery 20. Output power. As described above, when the second assembled battery 20 is deteriorated due to the salt concentration distribution, the deterioration due to the salt concentration distribution can be eliminated by charging the second assembled battery 20. For this reason, the charging power of the second assembled battery 20 for eliminating the deterioration due to the salt concentration distribution is the power W2in_req. The power W2in_req can be determined in advance by experiments or the like.

  In the process of step S103, the power supplied to the inverter 40 while charging the second assembled battery 20 using the output of the first assembled battery 10 (the sum of the output power W1out_c and W2out_c of the assembled batteries 10 and 20). It is determined whether or not it can be maintained. If the maximum output power W1out_max of the first assembled battery 10 is higher than the sum of the power W1out_c, the power W2out_c, and the power W2in_req, the power supplied to the inverter 40 can be maintained while charging the second assembled battery 20. .

  In the process of step S103, when the condition of the above formula (1) is satisfied, the controller 100 performs the process of step S104. On the other hand, when the condition of the above formula (1) is not satisfied, the controller 100 ends the process shown in FIG.

  In addition, when it is not necessary to maintain the electric power supplied to the inverter 40, in other words, when the electric power supplied to the inverter 40 may decrease, it is determined whether or not the condition of the above formula (1) is satisfied. It is not necessary to discriminate. Specifically, the process may proceed from step S102 to step S104. However, even in this case, it is necessary to secure the power supplied to the inverter 40 and the power for charging the second assembled battery 20 by the output power of the first assembled battery 10.

  In step S <b> 104, the controller 100 discharges the first assembled battery 10 and charges the second assembled battery 20 using the output power of the first assembled battery 10. Here, the output power of the first assembled battery 10 is the sum of the powers W1out_c, W2out_c, and W2in_req, as shown in FIGS. 5 and 6, time t1 corresponds to the threshold value t_th.

  At time t2 shown in FIGS. 5 and 6, the vehicle is driven using only the output power of the first assembled battery 10. Since the output power of the first assembled battery 10 at time t2 is higher than the sum of the power W1out_c and W2out_c, the output of the first assembled battery 10 (power W1out_c) and the output of the second assembled battery 20 (power W2out_c) are used. Electric power equal to that when the vehicle is running can be ensured. That is, the electric power when the vehicle is traveling at a time prior to time t1 can be made equal to the electric power when the vehicle is traveling at a time later than time t1.

  Moreover, since the output electric power of the 1st assembled battery 10 after the time t2 also contains electric power W2in_req, the 2nd assembled battery 20 can also be charged using electric power W2in_req. 5 and 6, the portion of the output power of the first assembled battery 10 that exceeds the sum of the power W1out_c and the power W2out_c is used for charging the second assembled battery 20, and the amount of discharge power of the first assembled battery 10 Eout is equal to the charge power amount Ein of the second assembled battery 20.

  In step S105, the controller 100 determines whether or not the electric energy Ein when charging the second assembled battery 20 is greater than the electric energy Ein_req for eliminating the deterioration (degradation due to the salt concentration distribution) of the second assembled battery 20. Is determined. Here, the electric energy Ein_req can be obtained in advance by an experiment or the like, and information on the electric energy Ein_req can be stored in the memory 101.

  When the electric energy Ein is greater than the required electric energy Ein_req, the controller 100 determines that the deterioration of the second assembled battery 20 (degradation due to the salt concentration distribution) has been eliminated by charging the second assembled battery 20, and in step S106 Process. On the other hand, when the power amount Ein is smaller than the required power amount Ein_req, the controller 100 continues the process of step S104.

  In step S106, first, the controller 100 calculates SOC1 (State of Charge) of the first assembled battery 10. The SOC indicates the ratio of the current charge capacity to the full charge capacity. Since the SOC has a correspondence with OCV (Open Circuit Voltage), the SOC can be specified by specifying the OCV if the correspondence is obtained in advance. The OCV can be obtained by detecting the voltage of the first assembled battery 10 in a state where the polarization of the unit cell 11 is relaxed. On the other hand, the SOC of the first assembled battery 10 can also be calculated by integrating the current value when the first assembled battery 10 is charged and discharged. Here, since the first assembled battery 10 continues to be discharged, the SOC of the first assembled battery 10 decreases.

  In step S106, controller 100 determines whether or not SOC1 of first assembled battery 10 is higher than lower limit value SOC_lim. The lower limit value SOC_lim is a lower limit value of SOC determined in advance from the viewpoint of securing the output of the first assembled battery 10. Information regarding the lower limit SOC_lim can be stored in the memory 101 in advance. When the SOC1 is higher than the lower limit SOC_lim, the controller 100 performs the process of step S107. On the other hand, when SOC1 is lower than the lower limit SOC_lim, the controller 100 performs the process of step S108.

  In step S107, the controller 100 discharges the first assembled battery 10 and the second assembled battery 20. As shown in FIG. 6, after the time t3 has elapsed, the second assembled battery 20 is switched from charging to discharging. Further, the first assembled battery 10 remains discharged. Here, the output power of the first assembled battery 10 is used as main power for running the vehicle, and the output power of the second assembled battery 20 is used as auxiliary power for running the vehicle. That is, as shown in FIG. 6, the controller 100 sets the output power of the first assembled battery 10 to the power W2out_c and sets the output power of the second assembled battery 20 to the power W1out_c.

  In the present embodiment, the output power of the second assembled battery 20 after the time t3 has elapsed is made equal to the output power W1out_c of the first assembled battery 10 until the time t1, but may be different from the output power W1out_c. it can. Further, the output power of the first assembled battery 10 after the time t3 has elapsed is made equal to the output power W2out_c of the second assembled battery 10 up to the time t1, but may be different from the output power W2out_c. That is, the power supplied to the inverter 40 may be equal before the time t1 and after the time t3 has elapsed.

  In FIG. 6, before the time t1, the output power of the second assembled battery 20 is used as the main power for driving the vehicle, and the output power of the first assembled battery 10 is used as an auxiliary for driving the vehicle. It is used as typical power. When performing the process of step S107, the relationship of the output power in the 1st assembled battery 10 and the 2nd assembled battery 20 becomes reverse to the relationship of the output power before the time t1.

  In step S107, after the output power of the first assembled battery 10 and the second assembled battery 20 is set, the first assembled battery 10 and the second assembled battery 20 are discharged under this setting condition. After performing step S107, the process returns to step S106. That is, the first assembled battery 10 and the second assembled battery 20 are discharged under the conditions set in step S107 until the SOC1 of the first assembled battery 10 becomes lower than the lower limit SOC_lim.

  In step S108, the controller 100 discharges the first assembled battery 10 and the second assembled battery 20. As shown in FIG. 5, after the time t3 has elapsed, the second assembled battery 20 is switched from charging to discharging. Further, the first assembled battery 10 remains discharged.

  Here, the output power of the second assembled battery 20 is used as main power for running the vehicle, and the output power of the first assembled battery 10 is used as auxiliary power for running the vehicle. That is, as shown in FIG. 5, the controller 100 returns the output power of the second assembled battery 20 to the power W2out_c and returns the output power of the first assembled battery 10 to the power W1out_c. After performing the process of step S107, the process shown in FIG. 4 is completed.

  In the present embodiment, the second assembled battery 20 is charged using the output power of the first assembled battery 10 to eliminate the deterioration due to the salt concentration distribution in the second assembled battery 20, but this is not the only case. It is not a thing. That is, by supplying the regenerative power generated by the motor generator 50 to the second assembled battery 20, it is possible to eliminate the deterioration due to the salt concentration distribution in the second assembled battery 20. Further, by using the regenerative power and the output power of the first assembled battery 10 together, it is possible to eliminate the deterioration due to the salt concentration distribution in the second assembled battery 20.

10: first assembled battery 20: second assembled battery 11, 21: single cell 12: fuse 13, 23: voltage sensor 14, 24: current sensor 15, 25: current limiting resistor 16, 17: capacitor 30: boost converter 31 : Reactor 32, 33: Transistor 34, 35: Diode 40: Inverter 50: Motor generator 100: Controller 101: Memory 102: Timer

Claims (2)

A motor generator as a drive source for running the vehicle;
A first assembled battery and a second assembled battery connected in parallel to the motor generator and supplying power to the motor generator;
A controller for controlling charging / discharging of the first assembled battery and the second assembled battery,
When the first assembled battery and the second assembled battery supply power to the motor generator, the output power of the second assembled battery is higher than the output power of the first assembled battery,
Wherein the controller is in the second assembled battery, when the deterioration due to the salt concentration distribution during discharge is generated by using the output power of the first assembled battery, thereby charging the second assembled battery, wherein A battery system, wherein the first assembled battery is discharged so as to satisfy a required power supplied to a motor generator. When the controller uses the output power of the first assembled battery to charge the second assembled battery and supplies power to the motor generator, the controller uses the output power of the first assembled battery as the first assembled battery. The total power when the second assembled battery supplies power to the motor generator and the power for charging the second assembled battery are added to each other. The battery system described.