Charge control device and charge control method

Abstract

To achieve a charging control device capable of suppressing a sense of discomfort of a user relative to a charging status of a battery.SOLUTION: A charging control device (2) calculates a reflection rate for reflecting a first charging current value in an allowable charging current value based on a relation between a damage amount of a battery and the reflection rate of the first charging current value and a current damage amount of the battery, calculates the first charging current value this time based on a relation among a remaining capacity of the battery, a temperature of the battery, and the first charging current value, a current remaining capacity of the battery, and a current temperature of the battery, calculates a second charging current value this time based on a relation among the remaining capacity of the battery, the temperature of the battery, and the second charging current value, the current remaining capacity of the battery, and the current temperature of the battery, and calculates an allowable charging current value this time based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a charge control device and a charge control method. [Background technology]

[0002] It is preferable to be able to suppress deterioration of a battery when charging the battery. For example, a charge control device in Patent Document 1 monitors the state of a battery, and when DC charging is not in progress, calculates a first allowable charging current value, which is a maximum current value at which metallic lithium does not precipitate on the negative electrode of the battery, according to the battery monitoring result, and calculates an input allowable power using the calculated first allowable charging current value, and when DC charging is in progress, calculates a second allowable charging current value, and calculates an input allowable power using the calculated second allowable charging current value.

[0003] At this time, the second allowable charging current value is set to a saturation current value at which the first allowable charging current value becomes saturated if DC charging is continued, thereby preventing a charging current that exceeds the saturation current value from flowing through the battery during DC charging, and preventing metallic lithium from being deposited on the negative electrode of the battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-68637 Summary of the Invention [Problem to be solved by the invention]

[0005] The present applicant has found the following problem: When the charge control device of Patent Document 1 charges a battery multiple times in a short period of time, as the battery deteriorates, the allowable charging current value becomes extremely low compared to the previous charging, causing the user to feel uncomfortable about the charging status of the battery.

[0006] The present disclosure has been made in consideration of such problems, and provides a charge control device and a charge control method that can suppress a user's discomfort regarding the charging status of a battery when the battery is being charged. [Means for solving the problem]

[0007] A charging control device according to an embodiment of the present disclosure is a charging control device for a battery that controls a charging current based on an allowable charging current value, A storage unit for storing a charging control program; A control unit that executes the charging control program; Equipped with the storage unit stores a first relationship between a preset amount of damage to the battery and a reflection rate at which a first charging current value is reflected in the allowable charging current value, a second relationship between a preset remaining capacity of the battery, a temperature of the battery, and the first charging current value, and a third relationship between a preset remaining capacity of the battery, a temperature of the battery, and a second charging current value that is reflected in the allowable charging current value and is smaller than the first charging current value; The control unit is Calculating the current amount of damage to the battery; calculating the reflection rate for reflecting the first charging current value in the current allowable charging current value based on the first relationship and the calculated amount of damage to the battery; calculating the first charging current value to be reflected in the allowable charging current value based on the second relationship, a current remaining capacity of the battery, and a current temperature of the battery; calculating the second charging current value to be reflected in the current allowable charging current value based on the third relationship, a current remaining capacity of the battery, and a current temperature of the battery; The allowable charging current value for charging the battery this time is calculated based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate.

[0008] A charging control method according to one aspect of the present disclosure is a charging control method for a battery, which controls a charging current based on an allowable charging current value, comprising: Calculating the current amount of damage to the battery; calculating a reflection rate for reflecting the first charging current value in the permissible charging current value based on a preset relationship between an amount of damage to the battery and a reflection rate for reflecting the first charging current value in the permissible charging current value and the calculated amount of damage to the battery; calculating the first charging current value to be reflected in the allowable charging current value based on a preset relationship between the remaining capacity of the battery, the temperature of the battery, and the first charging current value, and based on the current remaining capacity of the battery and the current temperature of the battery; calculating a second charging current value to be reflected in the allowable charging current value based on a relationship between a preset remaining capacity of the battery, a temperature of the battery, and a second charging current value that is smaller than the first charging current value, a current remaining capacity of the battery, and a current temperature of the battery; The allowable charging current value for charging the battery this time is calculated based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate. Effect of the Invention

[0009] According to the present disclosure, it is possible to realize a charge control device and a charge control method that can suppress a user's discomfort caused by the charging status of a battery when the battery is being charged. [Brief description of the drawings]

[0010] [Figure 1] 1 is an overall configuration diagram of a vehicle equipped with a charge control device according to an embodiment; [Diagram 2] FIG. 4 is a flowchart showing a process flow of a charge control program for implementing a charge control method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0012] First, a basic configuration of a vehicle 1 equipped with a charging control device 2 according to the present embodiment will be described. Fig. 1 is an overall configuration diagram of a vehicle equipped with a charging control device according to the present embodiment. Vehicle 1 is a plug-in hybrid vehicle.

[0013] However, the charging control device 2 of this embodiment is not limited to being installed in a plug-in hybrid vehicle, but can also be applied to vehicles (e.g., electric vehicles or fuel cell vehicles) that can externally charge the on-board battery (lithium ion secondary battery), and even to applications other than vehicles.

[0014] In this embodiment, the external charging will be described by taking DC (Direct Current) charging, which charges the on-board battery 10 using power supplied from a direct current power source external to the vehicle, as an example. The external charging may be AC ​​(Alternating current) charging, which charges the on-board battery 10 using power supplied from an alternating current power source external to the vehicle 1.

[0015] 1, the vehicle 1 includes a battery 10, a monitoring unit 15, system main relays (SMR) 25a, 25b, a power control unit (PCU) 30, motor generators 41, 42, an engine 50, a power split device 60, a drive shaft 70, drive wheels 75, a communication device 80, and an ECU (Electronic Control Unit) 100. The vehicle 1 also includes an inlet 90 and charging relays 91a, 91b as a configuration for performing DC charging.

[0016] The battery 10 is mounted on the vehicle 1 as a driving power source (i.e., a power source) of the vehicle 1. The battery 10 includes a plurality of stacked cells 11. The cells 11 in this embodiment are, for example, lithium ion secondary batteries.

[0017] The monitoring unit 15 detects the state of the battery 10. Specifically, the monitoring unit 15 includes a voltage sensor 16, a current sensor 17, and a temperature sensor 18. The voltage sensor 16 detects the terminal voltage of the battery 10 (hereinafter also referred to as "voltage VB"), and outputs a signal indicating the detection result to the ECU 100.

[0018] The current sensor 17 detects a current (hereinafter also referred to as "current IB") input to and output from the battery 10, and outputs a signal indicating the detection result to the ECU 100. The output of the current sensor 17 indicates a negative value when the battery 10 is being charged, and indicates a positive value when the battery 10 is being discharged.

[0019] The temperature sensor 18 detects the temperature of the battery 10 (hereinafter also referred to as “temperature TB”), and outputs a signal indicating the detection result to the ECU 100. The voltage sensor 16, the current sensor 17, or the temperature sensor 18 may be configured to detect the voltage, current, or temperature of a representative cell 11 (or a plurality of cells) of the battery 10.

[0020] The SMRs 25a and 25b are electrically connected to a power line connecting the battery 10 and the PCU 30. The SMRs 25a and 25b switch between supplying and cutting off power between the battery 10 and the PCU 30 in response to a control signal from the ECU 100.

[0021] In response to a control signal from the ECU 100, the PCU 30 converts the DC power stored in the battery 10 into AC power and supplies it to the motor generators 41, 42. The PCU 30 also converts the AC power generated by the motor generators 41, 42 into DC power and supplies it to the battery 10.

[0022] The PCU 30 is configured to be able to separately control the states of the motor generators 41, 42, and can, for example, put the motor generator 41 in a regenerative state while putting the motor generator 42 in a powering state. The PCU 30 is configured to include, for example, two inverters provided corresponding to the motor generators 41, 42, and a converter that boosts the DC voltage supplied to each inverter to a level equal to or higher than the output voltage of the battery 10.

[0023] Each of the motor generators 41 and 42 is an AC rotating electric machine, for example, a three-phase AC rotating electric machine with a permanent magnet embedded in a rotor (not shown). The motor generator 41 is connected to the crankshaft of the engine 50 via a power split device 60.

[0024] When starting the engine 50, the motor generator 41 uses the electric power of the battery 10 to rotate the crankshaft of the engine 50. The motor generator 41 is also capable of generating electricity using the power of the engine 50.

[0025] The AC power generated by the motor generator 41 is converted to DC power by the PCU 30 and charged into the battery 10. The AC power generated by the motor generator 41 may also be supplied to the motor generator .

[0026] The motor generator 42 rotates the drive shaft 70 using at least one of the power from the battery 10 and the power generated by the motor generator 41. The motor generator 42 can also generate power by regenerative braking during braking or when reducing acceleration. The AC power generated by the motor generator 42 is converted to DC power by the PCU 30 and charged into the battery 10.

[0027] The engine 50 is an internal combustion engine such as a gasoline engine or a diesel engine. The engine 50 is controlled by a control signal from the ECU 100. The power split device 60 is, for example, a planetary gear mechanism having three rotation shafts, a sun gear, a carrier, and a ring gear, and splits the power generated by the engine 50 into power transmitted to the drive wheels 75 and power transmitted to the motor generator 41.

[0028] The communication device 80 is configured to be able to communicate with the DC charging stand 200 via a communication signal line SL. The communication between the vehicle 1 and the DC charging stand 200 is performed, for example, by communication according to a Controller Area Network (CAN) communication protocol (hereinafter also referred to as "CAN communication"). Note that the communication between the vehicle 1 and the DC charging stand 200 is not limited to CAN communication, and may be performed, for example, by power line communication (PLC).

[0029] The inlet 90 is configured to be connectable to a charging connector 220 provided at an end of a charging cable 210 of the DC charging stand 200. The charging cable 210 includes power lines L1, L2 and a communication signal line L3. When the charging connector 220 is connected to the inlet 90, the power lines CPL, CNL and the communication signal line SL of the vehicle 1 are electrically connected to the power lines L1, L2 and the communication signal line L3 of the charging cable 210, respectively.

[0030] The charging relays 91a, 91b are electrically connected to a power line connecting the battery 10 and the inlet 90. The charging relays 91a, 91b switch between supplying and cutting off power between the battery 10 and the inlet 90 in response to a control signal from the ECU 100.

[0031] The ECU 100 includes a CPU (Central Processing Unit) 110, a memory 120, and an input / output port (not shown). The ECU 100 may be divided into a plurality of ECUs for different functions, such as an engine ECU that controls the engine 50, a charging ECU that controls charging of the battery 10, an MGECU that controls the motor generators 41 and 42 via the PCU 30, and the like.

[0032] The memory 120 includes a read only memory (ROM) and a random access memory (RAM), and is a storage unit that stores programs executed by the ECU 100, maps used for various controls, and the like.

[0033] In detail, the memory 120 stores, for example, a charging control program. The memory 120 also stores, for example, a first map showing a relationship between a preset damage amount of the battery 10 and a reflection rate at which a first charging current value is reflected in the allowable charging current value, a second map showing a preset relationship between the remaining capacity of the battery 10, the temperature of the battery 10, and the first charging current value, and a third map showing a preset relationship between the remaining capacity of the battery 10, the temperature of the battery 10, and the second charging current value reflected in the allowable charging current value.

[0034] Here, the allowable charging current value is a maximum current limit value when charging the battery 10. The first charging current value is a temporary allowable current value that is allowable for the cell durability of the battery 10 until the amount of damage to the battery 10 reaches a predetermined threshold. The second charging current value is a continuous allowable current value that is smaller than the first charging current value and is allowable for the cell durability regardless of the amount of damage to the battery 10.

[0035] The CPU 110 is a control unit that loads a program stored in the ROM into the RAM and executes it. The CPU 110 outputs control signals based on signals from the sensors and the maps stored in the memory 120, and controls the devices so that the vehicle 1 is in a desired state.

[0036] Such an ECU 100 functions as a charging control device 2 that controls DC charging. The ECU 100 outputs a control signal to the DC charging stand 200 via the communication device 80. The DC charging stand 200 supplies power to the vehicle 1 (inlet 90) in accordance with the control signal received from the vehicle 1. Note that the control of the engine 50 and motor generators 41, 42 by the ECU 100 is not essential to this disclosure and will not be described here.

[0037] Next, a process flow of a charge control program for implementing the charge control method of the present embodiment will be described. Fig. 2 is a flow chart showing a process flow of a charge control program for implementing the charge control method of the present embodiment. Note that the following process is executed repeatedly at a preset cycle.

[0038] First, the CPU 110 determines whether or not the battery 10 is being DC charged (S1). For example, when the inlet 90 of the vehicle 1 and the charging connector 220 of the DC charging stand 200 are connected, the CPU 110 determines that the battery 10 is being DC charged (YES in S1).

[0039] Next, when the battery 10 is being DC charged, the CPU 110 calculates the amount of damage to the battery 10 (S2). The CPU 110 can calculate the amount of damage to the battery 10 based on, for example, the following <Equation 1>.

[0040] <Formula 1> Amount of damage to battery 10=Previously calculated amount of damage to battery 10+predetermined first coefficient×(current current value of battery 10 / previously calculated first charging current value)

[0041] Here, the first coefficient can be set by calculating backward from a current load that does not cause high-rate degradation of the battery 10 when the battery 10 is continuously charged with the previously calculated first charging current value. However, the first coefficient can be set appropriately.

[0042] The current value of the battery is the current IB detected by the current sensor 17. , most When the amount of damage to the battery 10 was calculated for the first time, the first charging current value calculated last time was , not yet Because it has not been calculated, The damage amount of battery 10 calculated initially is set to 0. .

[0043] Next, CPU 110 calculates (S3) a reflection rate for reflecting the first charging current value in the current allowable charging current value based on the first map and the calculated amount of damage to battery 10. That is, CPU 110 calculates a reflection rate for reflecting the first charging current value in the current allowable charging current value based on a preset relationship between the amount of damage to battery 10 and the reflection rate for reflecting the first charging current value in the allowable charging current value, and the calculated amount of damage to battery 10.

[0044] Next, CPU 110 calculates (S4) a first charging current value to be reflected in the current allowable charging current value based on the second map, the current remaining capacity of battery 10, and the current temperature of battery 10. That is, CPU 110 calculates the first charging current value to be reflected in the current allowable charging current value based on a preset relationship between the remaining capacity of battery 10, the temperature of battery 10, and the first charging current value, the current remaining capacity of battery 10, and the current temperature of battery 10.

[0045] Here, the remaining capacity of the battery 10 can be calculated by a voltage measurement method based on the voltage VB detected by the voltage sensor 16, or a current measurement method based on the current IB detected by the current sensor 17. In this case, the remaining capacity of the battery 10 may be, for example, the largest remaining capacity among the calculated remaining capacities of the cells 11, and more specifically, the maximum remaining capacity of all the cells 11.

[0046] The temperature of the battery 10 is the temperature TB detected by the temperature sensor 18. At this time, the lowest temperature among the temperatures of all the cells 11 detected by the temperature sensor 18 should be used as the temperature of the battery 10.

[0047] Next, CPU 110 calculates (S5) a second charging current value to be reflected in the current allowable charging current value based on the third relationship, the current remaining capacity of battery 10, and the current temperature of battery 10. That is, CPU 110 calculates the second charging current value to be reflected in the current allowable charging current value based on a preset relationship between the remaining capacity of battery 10, the temperature of battery 10, and the second charging current value, the current remaining capacity of battery 10, and the current temperature of battery 10.

[0048] Next, the CPU 110 calculates an allowable charging current value for currently charging the battery 10 based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate (S6). In detail, the CPU 110 can calculate the allowable charging current value based on, for example, the following <Equation 2>.

[0049] <Formula 2> Allowable charging current value = This time calculated first charging current value × calculated reflection rate + This time calculated second charging current value × (1 - calculated reflection rate)

[0050] The CPU 110 generates a control signal and controls the DC charging stand 200 based on the control signal so that the battery 10 is charged with the current allowable charging current value calculated in this manner. At this time, the first charging current value and the second charging current value can be increased or decreased according to the amount of damage to the battery 10, and it is possible to prevent the allowable charging current value from becoming extremely low compared to the charging time in the previous cycle. Therefore, the change in the charging status of the battery 10, such as the charging time, is small compared to the charging time in the previous cycle, and it is possible to prevent the user from feeling uncomfortable.

[0051] On the other hand, for example, when the inlet 90 of the vehicle 1 and the charging connector 220 of the DC charging stand 200 are not connected, the CPU 110 determines that the battery 10 is not undergoing DC charging (NO in S1), and reduces the amount of damage to the battery 10 calculated previously by a preset reduction amount for each of the above-mentioned periods (S7).

[0052] Here, the preset reduction amount can be set according to, for example, the speed at which the electrolyte concentration unevenness in the electrolyte of the battery 10 is alleviated when DC charging is stopped. Note that the cycle for reducing the previously calculated amount of damage to the battery 10 by the preset reduction amount may be different from the above-mentioned cycle.

[0053] The amount of damage to the battery 10 calculated in this manner can be used as the amount of damage to the battery 10 calculated previously, for example, when the amount of damage to the battery 10 is calculated for the first time after DC charging of the battery 10 is started. This makes it possible to increase the first charging current value according to the degree of recovery of the amount of damage to the battery 10. Therefore, it is possible to calculate an appropriate allowable charging current value according to the amount of damage to the battery 10.

[0054] In this way, the charge control device and the charge control method of the present embodiment can increase or decrease the first charge current value and the second charge current value according to the amount of damage to the battery 10, and can prevent the allowable charge current value from becoming extremely low compared to the previous charging period. Therefore, the change in the charging status, such as the charging time of the battery 10, is small compared to the previous charging period, and discomfort felt by the user can be reduced.

[0055] Moreover, the charge control device and the charge control method of the present embodiment reduce the previously calculated amount of damage to the battery 10 at preset intervals when the battery 10 is not DC charged. This makes it possible to increase the first charging current value according to the degree of recovery of the amount of damage to the battery 10. Therefore, it is possible to calculate an appropriate allowable charging current value according to the amount of damage to the battery 10.

[0056] In addition, the present disclosure is not limited to the above embodiment, and can be appropriately modified without departing from the spirit and scope of the present disclosure. For example, it is not limited to a map, and it is sufficient if each relationship is shown. [Explanation of symbols]

[0057] 1 vehicle, 2 charging control device, 10 battery, 11 cell, 15 monitoring unit, 16 voltage sensor, 17 current sensor, 18 temperature sensor, 41, 42 motor generator, 50 engine, 60 power split device, 70 drive shaft, 75 drive wheel, 80 communication device, 90 inlet, 91a, 91b charging relay, 100 ECU, 110 CPU, 120 memory, 200 DC charging stand, 210 charging cable, 220 charging connector

Claims

1. A battery charge control device that controls a charge current based on an allowable charge current value, A storage unit for storing a charging control program; A control unit that executes the charging control program; Equipped with the storage unit stores a first relationship between a preset amount of damage to the battery and a reflection rate at which a first charging current value is reflected in the allowable charging current value, a second relationship between a preset remaining capacity of the battery, a temperature of the battery, and the first charging current value, and a third relationship between a preset remaining capacity of the battery, a temperature of the battery, and a second charging current value that is reflected in the allowable charging current value and is smaller than the first charging current value; The control unit is Calculating the current amount of damage to the battery; calculating the reflection rate for reflecting the first charging current value in the current allowable charging current value based on the first relationship and the calculated amount of damage to the battery; calculating the first charging current value to be reflected in the allowable charging current value based on the second relationship, a current remaining capacity of the battery, and a current temperature of the battery; calculating the second charging current value to be reflected in the current allowable charging current value based on the third relationship, a current remaining capacity of the battery, and a current temperature of the battery; calculating the allowable charging current value for currently charging the battery based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate; Charging control device.

2. 2 . The charge control device according to claim 1 , wherein, when the battery is not being charged, the control unit reduces an amount of damage to the battery by a preset reduction amount for each preset first period.

3. 3. The charging control device according to claim 1, wherein the control unit calculates the allowable charging current value at a predetermined second period, and calculates the amount of damage to the battery for each second period based on the following Equation 1. <Equation 1> Amount of damage to battery=Previously calculated amount of damage to battery+Previously set coefficient×(Current battery current value / Previously calculated first charging current value) However, the amount of damage to the battery that is initially calculated is set to zero.

4. The charge control device according to claim 1 , wherein the control unit calculates the allowable charging current value based on the following <Equation 2>. <Formula 2> Allowable charging current value=Currently calculated first charging current value×Calculated reflection rate+Currently calculated second charging current value×(1−Calculated reflection rate)

5. A method for controlling charging of a battery, the method comprising: controlling a charging current based on an allowable charging current value, the method comprising: Calculating the current amount of damage to the battery; calculating a reflection rate for reflecting the first charging current value in the permissible charging current value based on a preset relationship between an amount of damage to the battery and a reflection rate for reflecting a first charging current value in the permissible charging current value and the calculated amount of damage to the battery; calculating the first charging current value to be reflected in the allowable charging current value based on a preset relationship between the remaining capacity of the battery, the temperature of the battery, and the first charging current value, a current remaining capacity of the battery, and a current temperature of the battery; calculating the second charging current value to be reflected in the allowable charging current value based on a relationship between a preset remaining capacity of the battery, a temperature of the battery, and a second charging current value that is smaller than the first charging current value, a current remaining capacity of the battery, and a current temperature of the battery; calculating the allowable charging current value for currently charging the battery based on the calculated first charging current value, the calculated second charging current value, and the calculated reflection rate; Charging control method.

Images