JP2018008547A - Battery control system of hybrid vehicle - Google Patents

Abstract

In a battery control system for a hybrid vehicle, battery deterioration is suppressed and power performance during EV traveling is increased. A battery control system includes a control device that controls discharge power to a battery. The control device expands the allowable discharge power from the battery during EV traveling more than during HV traveling, and is the base allowable power that is the allowable discharge power during HV traveling and the maximum value of the allowable discharge power during EV traveling. Calculate the maximum allowable power. During EV traveling, the control device calculates a coefficient having a smaller value out of the first deterioration coefficient K1 based on the increase amount of the internal resistance value of the battery with respect to the initial value and the second deterioration coefficient K2 based on the elapsed use time of the battery. Then, by multiplying the difference between the maximum allowable power and the base allowable power, the amount of expansion of the discharge allowable power during EV traveling is calculated. [Selection] Figure 2

Description

  The present invention relates to a battery control system for a hybrid vehicle that includes an electric motor connected to a battery and an engine and travels using one or both of the electric motor and the engine as a drive source.

  Conventionally, a hybrid vehicle that includes an electric motor and an engine and travels using one or both of the electric motor and the engine as a drive source is known. A hybrid vehicle is equipped with a battery, which is a power storage unit, for supplying electric power to the electric motor. In the hybrid vehicle, an EV traveling mode in which driving of the engine is prohibited and the vehicle is driven by driving of the electric motor, and an HV traveling mode in which driving of the engine is permitted and the vehicle is driven are set. The EV traveling mode and the HV traveling mode are switched according to a vehicle request such as a user request or a vehicle request driving force.

  In Patent Document 1, a reference voltage value is calculated using a current voltage value, a current value, and an internal resistance value of an assembled battery corresponding to a battery, and discharging is possible using the reference voltage value and a predetermined internal resistance value. A configuration for calculating a power value is described. In this configuration, the predetermined internal resistance value is set higher than the current internal resistance value. Thereby, it is supposed that the dischargeable power value can be set in consideration of deterioration of the assembled battery.

JP, 2015-119558, A

  By the way, during EV traveling of the hybrid vehicle, it is desired to increase the power performance by increasing the discharge allowable power of the battery. On the other hand, if the state where the allowable discharge power of the battery is kept high is maintained, the battery may be deteriorated at an early stage. In the configuration described in Patent Document 1, there is room for improvement from the viewpoint of achieving both the suppression of the deterioration of the battery and the increase of the power performance by setting the discharge allowable power high during EV traveling.

  An object of the present invention is to suppress battery deterioration and increase power performance during EV traveling in a battery control system for a hybrid vehicle.

  A battery control system for a hybrid vehicle according to the present invention is a battery control system for a hybrid vehicle that includes an electric motor connected to a battery and an engine and travels using one or both of the electric motor and the engine as a drive source. . The battery control system includes a control device that controls discharge power to the battery. In the EV traveling that travels by prohibiting driving of the engine and driving the electric motor, the control device allows the discharge allowable power from the battery to be higher than in HV traveling that travels while permitting the driving of the engine. The base allowable power, which is the discharge allowable power during the HV traveling, and the maximum allowable power, which is the maximum value of the discharge allowable power during the EV traveling, are calculated. The battery deterioration coefficient calculated from the increase amount of the internal resistance value relative to the initial value, which is calculated based on the first deterioration coefficient corresponding to the ratio of the increase amount of the discharge allowable power and the battery usage elapsed time. Among the second deterioration coefficients corresponding to the ratio of the expansion amount of the discharge allowable power, the coefficient having a small value is set as the maximum allowable power and the base. By multiplying the difference between the volume power, to calculate the expansion amount of said discharge allowable power during the EV traveling.

  According to the battery control system for a hybrid vehicle according to the present invention, it is possible to suppress the deterioration of the battery and improve the power performance during EV traveling.

1 is a diagram illustrating a basic configuration and a circuit of a battery control system and a hybrid vehicle according to an embodiment of the present invention. It is a figure which shows the flowchart for demonstrating the calculation method of the discharge allowable electric power Wout at the time of EV driving | running | working of embodiment. In the embodiment, a diagram (a) showing a relationship between a vehicle elapsed year that is an elapsed time from the start of the first start of the control device and a discharge allowable power Wout calculated value, and a relationship between the vehicle elapsed year and the second deterioration coefficient K2. FIG. It is a 1st relationship used by embodiment, Comprising: It is a figure which shows the relationship between the increase amount (resistance increase amount) with respect to the initial value of the internal resistance value of a battery, and the 1st degradation coefficient K1. It is a 2nd relationship used by embodiment, Comprising: It is a figure which shows the relationship between vehicle elapsed years and the 2nd degradation coefficient K2.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, a case where a second motor generator having both functions of an electric motor and a generator is used as an electric motor for driving a wheel will be described. However, the electric motor may not have a function of a generator. . In addition, the numerical values and the number described below are examples for explanation, and can be appropriately changed according to the specifications of the battery control system of the hybrid vehicle. In the following, when a plurality of embodiments and modified examples are included, they can be implemented by appropriately combining them. In the following description, identical elements are denoted by the same reference symbols in all drawings. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a basic configuration and a circuit of a battery control system 12 and a hybrid vehicle 10 according to the embodiment. A one-dot chain line in FIG. 1 represents a signal line.

  The hybrid vehicle 10 on which the battery control system 12 is mounted will be described. The hybrid vehicle 10 travels using one or both of the second motor generator 18 and the engine 50 as a drive source. Specifically, the hybrid vehicle 10 includes a battery control system 12, an engine 50, a power distribution mechanism 51, and wheels 52. The battery control system 12 includes a battery 15, a first motor generator 16, a second motor generator 18 that is an electric motor for driving wheels, a current sensor 19, a voltage sensor 20, a temperature sensor 21, and a control device 22. .

  The battery 15 includes a battery module that includes a plurality of battery cells that are secondary batteries such as a nickel metal hydride battery or a lithium ion battery, and is configured by electrically connecting the plurality of battery cells in series or in parallel. The battery 15 may be a battery pack configured by electrically connecting a plurality of battery modules in series. The first motor generator 16 and the second motor generator 18 are connected to the battery 15. The DC voltage output from the battery 15 is boosted by the step-up / down converter 23. The boosted DC power is converted into three-phase AC power by the inverter 24. The converted AC power is supplied to at least one of the first motor generator 16 and the second motor generator 18. Hereinafter, the first motor generator 16 is referred to as a first MG 16, and the second motor generator 18 is referred to as a second MG 18. In FIG. 1, the first MG 16 and the second MG 18 are denoted as MG1 and MG2, respectively.

  Here, each of the first MG 16 and the second MG 18 has both functions of an electric motor and a generator. The first MG 16 is driven by electric power from the battery 15 and also has a function as a starter motor that starts the engine 50. The second MG 18 is driven by being supplied with electric power from the battery 15 and used to drive the vehicle. Specifically, the driving force of the second MG 18 is transmitted to the wheels 52 via the power distribution mechanism 51, and the wheels 52 are driven. The second MG 18 is also used as a generator that charges the battery 15 by regenerative power generation during braking of the vehicle and supplying power to the battery 15.

  The engine 50 is connected to the power distribution mechanism 51 and can drive the wheels 52 by the output of the engine 50. Further, the output of the engine 50 can be transmitted to the first MG 16 to generate electric power there.

  Further, in the hybrid vehicle 10, an EV travel mode and an HV travel mode are set, and the control device 22 described later switches so as to select either the EV travel mode or the HV travel mode according to a user request or a vehicle situation. The hybrid vehicle travels in the selected travel mode. The user request is generated by a user operation using an operation unit such as a switch or a button. The vehicle status is a state of charge (SOC) that is a ratio of the charging capacity to the full charging capacity of the battery 15, a vehicle required driving force based on an accelerator operation, or the like.

  In the EV travel mode, the driving of the engine 50 is stopped and the vehicle is traveled by the power of the second MG 18. The HV travel mode is a mode in which the engine 50 is allowed to drive and travels by appropriately driving the engine 50 according to the travel state (SOC, output request, etc.). That is, at least one of the engine 50 and the second MG 18 is driven to travel, and power is generated when the SOC decreases. Further, depending on the traveling situation, the vehicle travels only with the driving force of the engine 50. For example, the HV traveling mode can be a mode for traveling so as to maintain the SOC within a predetermined range. At this time, when the SOC falls below the lower limit of the predetermined range, the first MG 16 generates electric power by driving the engine. When the SOC exceeds the upper limit of the predetermined range in consideration of hysteresis, the engine driving is stopped, and the second MG 18 The vehicle is driven only by power.

  That is, the driving force of the second MG 18 and the engine 50 is transmitted to the wheels 52 via the power distribution mechanism 51, and the hybrid vehicle 10 travels using one or both of the second MG 18 and the engine 50 as a driving source. Note that the term “during HV traveling” may be in the HV traveling mode, or may be limited to when both the electric motor and the engine are driven in the HV traveling mode. The term “during EV travel” may include a state in which the engine is not driven in the HV travel mode.

  On the other hand, the driving force of the engine 50 is transmitted to the first MG 16 via the power distribution mechanism 51, whereby the first MG 16 is driven to generate power. The generated power is converted from alternating current to direct current by the inverter 24 and then stepped down by the step-up / down converter 23. Then, the electric power after the step-down is supplied to the battery 15 and the battery 15 is charged.

  The control device 22 is configured by a computer, for example, and includes a CPU that is a calculation unit and a storage unit such as a memory and a hard disk device. The control device 22 controls various devices in the vehicle. For example, the control device 22 controls on / off operations of switching elements (not shown) of the step-up / down converter 23 and the inverter 24 to control the rotation speed or torque of the first MG 16 and the second MG 18. Further, the control device 22 controls the on / off operation of the switching element of the step-up / down converter 23 to control the step-up / step-down operation.

  Moreover, the control apparatus 22 receives the signal showing a detected value from the various sensors mounted in the vehicle. Specifically, signals representing the current value, voltage value, and detected temperature value of the battery 15 are transmitted from the current sensor 19, the voltage sensor 20, and the temperature sensor 21 to the control device 22, respectively. Control device 22 calculates the SOC by integrating the current value of battery 15 detected by current sensor 19. The SOC can also be calculated from the battery voltage value detected by the voltage sensor 20.

  In addition, the control device 22 measures a “vehicle elapsed year”, which is an elapsed time from when the vehicle is completed and the control device 22 first starts to start, using a timer. Since the start of activation of the control device 22 substantially coincides with the start of use of the battery 15, the elapsed vehicle age substantially coincides with the “elapsed battery use time” that is the elapsed year from the start of use of the battery 15. . Alternatively, the date of completion of the vehicle at the factory may be stored in the control device 22 and the “year of vehicle lapse” may be calculated from the difference from the current date recognized by the vehicle. Further, the “vehicle elapsed years” is used for determining the deterioration of the battery 15, and when the battery 15 has a storage unit such as a memory, the date of production is stored in the storage unit. Alternatively, the control device 22 may read out the production date and use it as the “vehicle age”. “Vehicle elapsed years” do not need to be accurate until the date and time, and the start of the elapsed time may be a vehicle sales date or the like, and may be any as long as it indicates the elapsed usage time of the battery 15. Furthermore, the battery usage elapsed time may be set in consideration of the number of times of charging / discharging, an integrated value of charging / discharging current, and the like. In addition, when the battery 15 is replaced, the usage elapsed time may be started from that time. In addition, when only the control device 22 is replaced, information on the battery usage elapsed time may be taken over by some method.

  Further, the control device 22 connects the battery 15 and the inverter 24 when the start switch (not shown) is turned on by the user and the system main relay 25 is switched from off to on. As a result, the battery control system 12 is activated. On the other hand, the control device 22 disconnects the connection between the battery 15 and the inverter 24 when the start switch is turned off by the user and the system main relay 25 is switched from on to off. Thereby, the battery control system 12 will be in a halt condition.

  The control device 22 controls discharge power and charge power for the battery 15. When the discharge of the battery 15 is controlled, the discharge allowable power Wout is set. The control device 22 controls the discharge of the battery 15 so that the discharge power does not exceed the discharge allowable power Wout.

  Discharge allowable power Wout differs between EV traveling and HV traveling. Specifically, the control device 22 at least when the vehicle elapsed years, which is an elapsed time since the start of the start of the control device 22 for the first time, is within a predetermined time, during EV travel, than during HV travel, The discharge allowable power Wout from the battery 15 is increased. Therefore, the control device 22 calculates “base Wout” that is base allowable power and “expanded Wout” as maximum allowable power that is the maximum value of discharge allowable power during EV traveling. The base Wout is discharge allowable power for setting the discharge power during HV traveling. The expansion Wout is used for calculating the expansion amount of the discharge allowable power Wout from the base Wout during EV traveling.

  More specifically, discharge allowable power WoutQ1 (FIG. 3) during EV traveling is calculated by adding an expansion amount Q3 (FIG. 3) of discharge allowable power Wout to base WoutQ2 (FIG. 3) (Q1). = Q2 + Q3). Thereby, since the electric power taken out from the battery 15 at the time of EV running becomes larger than the electric power taken out at the time of HV running, the vehicle driving force at the time of EV running can be increased. In addition, since the discharge allowable power Wout is smaller during HV traveling than during EV traveling, the battery 15 can be prevented from being continuously taken out and the battery life can be extended.

  Furthermore, a coefficient having a smaller value is used for calculating the expansion amount of the discharge allowable power Wout among the first deterioration coefficient K1 and the second deterioration coefficient K2. The first deterioration coefficient K1 is a battery deterioration coefficient calculated from an increase amount of the internal resistance value of the battery 15 with respect to the initial value at the initial use. The second deterioration coefficient K2 is a battery deterioration coefficient calculated based on the vehicle age. Specifically, the discharge allowable power Wout is calculated by multiplying the difference between the expanded Wout and the base Wout by a coefficient having a smaller value out of the first deterioration coefficient K1 and the second deterioration coefficient K2. Hereinafter, the increase amount with respect to the initial value of the internal resistance value of the battery 15 is referred to as a resistance increase amount.

  The first deterioration coefficient K1 and the second deterioration coefficient K2 respectively correspond to the ratio of the increase amount of the discharge allowable power Wout for multiplying the above difference. Thereby, in the calculation of the expansion amount of the discharge allowable power Wout, a coefficient that makes the discharge allowable power smaller is used among the two coefficients K1 and K2 calculated from the resistance increase amount of the battery 15 and the vehicle age. For this reason, since it can suppress more effectively that discharge electric power is taken out from the battery 15, deterioration of the battery 15 can be suppressed more effectively.

  FIG. 2 is a flowchart illustrating a method for calculating the discharge allowable power Wout during EV travel according to the embodiment. FIG. 3 is a diagram (a) showing the relationship between the elapsed vehicle time that is the elapsed time from the start of the first start of the control device and the calculated discharge allowable power Wout, and the elapsed vehicle time and the second deterioration coefficient in the embodiment. It is a figure (b) which shows the relationship with K2.

  The calculation method of discharge allowable power Wout shown in FIG. 2 is executed as a pre-stage treatment when setting discharge power. For example, the discharge power is set so as not to exceed the set allowable discharge power Wout in each of the “travel trips” that are a plurality of system activation states. Each traveling trip means a state from Ready On to Ready Off. A program for executing the flowchart shown in FIG. 2 is stored in the storage unit of the control device 22 and is executed when the control device 22 is activated. This program is executed when the vehicle age is within a predetermined time, for example, within B5 (year) shown in FIG. When the vehicle age exceeds B5 (year), the discharge allowable power is such that the value gradually decreases with the increase of the vehicle age in both EV running and HV running due to the base deterioration coefficient described later. Wout is set.

  When the control device 22 is activated by the user's turning-on operation of the start switch (becomes Ready ON state), in step S10, it is determined whether or not the control device 22 is in EV travel. Hereinafter, step S is simply referred to as S. If the determination result in step S10 is affirmative, that is, if the vehicle is traveling on an EV, the enlarged WoutQa (FIG. 3) and the base WoutQ2 (FIG. 3) are calculated by the control device 22 in S11. Each of the expansion WoutQa and the base WoutQ2 is obtained using a map indicating a preset relationship using the calculated current SOC and the detected temperature of the battery 15. For this purpose, the storage unit of the control device 22 stores in advance a map showing the relationship between the SOC, the battery temperature, and the expanded WoutQa. The storage unit of the control device 22 also stores a map indicating the relationship among the SOC, the battery temperature, and the base WoutQ2. As a map, the relationship among the SOC, the temperature of the battery 15, and the expansion Wout or the base Wout can be shown in a three-axis space including an orthogonal x-axis, y-axis, and z-axis.

  In FIG. 3, the horizontal axis indicates the vehicle age, and the vertical axis indicates the calculated value of the discharge allowable power Wout from the battery during EV travel. As shown in FIG. 3, the discharge allowable power Wout during EV traveling gradually decreases as the vehicle age increases. In the example shown in FIG. 3A, the discharge allowable power Wout during EV travel is maintained at a constant expansion WoutQa with the vehicle age from 0 to B1. Then, when the vehicle age is from B1 to B5, discharge allowable power Wout during EV traveling gradually decreases and reaches base WoutQ2. When the vehicle age is B5 or later, discharge allowable power Wout during EV traveling and HV traveling gradually decreases from base WoutQ2 during B5 according to a preset base deterioration coefficient. The base deterioration coefficient is set separately from the first deterioration coefficient K1 and the second deterioration coefficient K2. The enlarged WoutQa is not calculated when the vehicle age is B5 or later.

  Next, in S <b> 13, a resistance increase amount that is an increase amount with respect to the initial value of the internal resistance value of the battery 15 is calculated or acquired by the control device 22. For example, the internal resistance value of the battery 15 is calculated based on the current value and the voltage value of the battery 15 transmitted from the current sensor 19 and the voltage sensor 20, and the amount of increase from the internal resistance value with respect to the initial value of the internal resistance value ( Resistance increase amount) is calculated. In S14, the first deterioration coefficient K1 is calculated from the calculated resistance increase amount.

  The first deterioration coefficient K1 may be calculated based on a resistance increase amount of the battery 15 from a preset relational expression. On the other hand, the control device 22 stores in advance map data indicating the relationship between the resistance increase amount of the battery 15 and the first deterioration coefficient K1, and the first deterioration coefficient K1 is calculated from the calculated resistance increase amount. May be.

  FIG. 4 is a diagram illustrating a first relationship used in the embodiment and a relationship between the battery resistance increase amount (mΩ) and the first deterioration coefficient K1. The first deterioration coefficient K1 is in the range of 0 to 1.0. In FIG. 4, A1, A2,... A5 increase in order as A1 <A2 <A3. The controller 22 can store map data indicating the relationship shown in FIG.

  In S13 of FIG. 2, instead of calculating the internal resistance value and the resistance increase amount of the battery 15 each time, the previous travel trip based on the average value of the plurality of internal resistance values calculated in the previous one travel trip. The amount of increase in resistance may be acquired. At this time, for example, in each traveling trip, the internal resistance value of the battery 15 is calculated at a plurality of preset timings and stored in the storage unit of the control device 22. Then, the control device 22 calculates an average value of the internal resistance value immediately before the end of one trip, that is, after the start switch is turned off and before Ready Off, and calculates the increase in resistance of the battery from the average value. Calculate and store. In the next travel trip, discharge allowable power Wout is calculated using the stored previous increase in resistance.

  Returning to FIG. 2, in S <b> 15, the vehicle age is acquired by measurement using the timer of the control device 22. In S16, the second deterioration coefficient K2 is calculated from the vehicle age.

  The second deterioration coefficient K2 may be calculated based on the age of the vehicle from a preset relational expression. On the other hand, the control device 22 may store map data indicating the relationship between the vehicle age and the second deterioration coefficient K2 in advance, and the second deterioration coefficient K2 may be calculated from the acquired vehicle age. .

  FIG. 5 is a diagram showing a second relationship used in the embodiment and a relationship between the vehicle age and the second deterioration coefficient K2. The second deterioration coefficient K2 is in the range of 0 to 1.0. In FIG. 5, B1, B2,... B5 increase in order as B1 <B2 <B3. The controller 22 can store map data indicating the relationship of FIG.

  Returning to FIG. 2, in S17, the control device 22 determines whether or not the first deterioration coefficient K1 is smaller than the second deterioration coefficient K2. When the determination result in S17 is affirmative, the control device 22 multiplies the difference (Qa−Q2) (FIG. 3) between the enlarged Wout and the base Wout by the first deterioration coefficient K1 on the smaller side. Thereby, the control device 22 calculates the expansion amount Q3 (FIG. 3) of the discharge allowable power Wout during EV traveling as the multiplication result (S18). In S20, discharge allowable power WoutQ1 (FIG. 3) during EV traveling is calculated by adding the multiplication result in S18 to base WoutQ2 (FIG. 3).

  On the other hand, if the determination result in S17 is negative, that is, if the first deterioration coefficient K1 is greater than or equal to the second deterioration coefficient K2, in S19, the control device 22 adds the second deterioration coefficient to the difference between the enlarged Wout and the base Wout. Multiply by K2. Thereby, the control device 22 calculates the expansion amount of the discharge allowable power Wout during EV traveling as the multiplication result. In S20, the allowable discharge power Wout during EV traveling is calculated by adding the multiplication result in S10 to the base Wout.

  The discharge allowable power Wout obtained in S20 is used as an upper limit value when setting the discharge power during EV traveling.

  On the other hand, if the determination result in S10 of FIG. 2 is negative, there is a possibility that the vehicle is traveling in HV. At this time, in S12, the control device 22 calculates the base Wout as in the case of S11 described above. This base Wout is used as an upper limit value for setting the discharge power during HV traveling. When the processes of S20 and S12 are completed, the process returns to S10 and the process is repeated unless the vehicle age exceeds a predetermined time, for example, B5 years. When the age of the vehicle exceeds a predetermined time, discharge allowable power Wout is set using a base deterioration coefficient that is another deterioration coefficient.

  According to said battery control system 12, deterioration of the battery 15 can be suppressed and the power performance at the time of EV driving | running | working can be made high. In FIG. 3A, the hatched portion indicates a portion of the allowable discharge power Wout during EV travel that exceeds the base Wout, which is the allowable discharge power during HV travel. In the example shown in FIG. 3A, the second deterioration coefficient K2 is smaller than the first deterioration coefficient K1 when the vehicle age is from B1 to B3. As a result, the discharge allowable power Wout during EV travel is gradually reduced in accordance with the slope of the second deterioration coefficient K2 shown in FIG.

  On the other hand, when the vehicle age is from B3 to B5, the first deterioration coefficient K1 is smaller than the second deterioration coefficient K2. When the vehicle age is from B3 to B5, the resistance increase amount of the battery 15 is changed in the middle, and the first deterioration coefficient K1 is also changed in the middle. The discharge allowable power Wout during EV travel is smaller than that until B3 due to the two first deterioration coefficients K1 set according to the two resistance increase amounts.

As shown in FIG. 3 (a), in the embodiment, the allowable discharge power Wout is higher during EV traveling than during HV traveling until the vehicle age reaches the predetermined time B5. Thereby, deterioration of the battery 15 can be suppressed and the power performance during EV traveling can be increased.

  In the example shown in FIG. 3, the base deterioration coefficient is set when the vehicle age is B5 or later. Then, the base deterioration coefficient is calculated from the relational expression between the preset base deterioration coefficient and the vehicle age in accordance with the vehicle age. At this time, similarly to the maps shown in FIGS. 4 and 5, a map indicating the relationship between the vehicle age and the base deterioration coefficient is stored in the control device 22, and the base deterioration coefficient may be calculated from the vehicle age. .

  When the vehicle age exceeds B5, the common discharge allowable power during EV travel and HV travel is gradually reduced according to the base deterioration coefficient obtained from the vehicle age. The base deterioration coefficient is a value of 1.0 or less, and gradually decreases from 1.0 in accordance with an increase in the vehicle age from B5. The discharge allowable power Wout after the vehicle age of B5 is calculated by multiplying the base WoutQ2 at the time of B5 by a base deterioration coefficient corresponding to the age. FIG. 3 shows that the process for calculating the expanded Wout is until the vehicle elapsed years until B5, and the process for calculating the discharge allowable power Wout in consideration of deterioration after B5. Note that the discharge allowable power during EV traveling may be set to be always higher than the discharge allowable power during HV traveling.

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Battery control system, 15 Battery, 16 1st motor generator (1st MG), 18 2nd motor generator (2nd MG), 19 Current sensor, 20 Voltage sensor, 21 Temperature sensor, 22 Control apparatus, 24 Inverter , 25 system main relay, 50 engine, 51 power distribution mechanism, 52 wheels.

Claims (1)

An electric motor connected to the battery and an engine;
A battery control system for a hybrid vehicle that travels using one or both of the electric motor and the engine as a drive source,
A control device for controlling discharge power to the battery;
The controller is
In EV traveling that travels by prohibiting driving of the engine and driving the electric motor, the discharge allowable power from the battery is increased compared to HV traveling that travels while permitting driving of the engine,
Calculating a base allowable power that is the discharge allowable power during the HV traveling and a maximum allowable power that is the maximum value of the discharge allowable power during the EV traveling;
A battery deterioration coefficient calculated from an increase amount of the internal resistance value of the battery with respect to an initial value during the EV traveling, the first deterioration coefficient corresponding to a ratio of the increase amount of the discharge allowable power, and use of the battery The battery degradation coefficient calculated based on the elapsed time and having a smaller value among the second degradation coefficients corresponding to the ratio of the increase amount of the discharge allowable power, the maximum allowable power and the base allowable power. The battery control system for a hybrid vehicle that calculates the amount of increase in the discharge allowable power during the EV travel by multiplying the difference with the above.

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