Battery control system for a vehicle

Abstract

In a battery control system of a vehicle of the present disclosure, a temperature determination section determines whether the temperature of a battery pack is equal to or higher than a prescribed minimum threshold temperature. A battery connection / disconnection control section controls a battery connection / disconnection section in such a manner that a first prescribed number of battery packs are connected to a load when it is determined by the temperature determination section that the temperature of all of the battery packs among a plurality of battery packs is equal to or higher than the minimum threshold temperature, and in such a manner that a second prescribed number of battery packs, which is less than the first prescribed number, are connected to the load when it is determined by the temperature determination section that the temperature of all of the battery packs among the plurality of battery packs is lower than the minimum threshold temperature.

Description

Technical Field

[0001] This disclosure relates to a battery control system for vehicles. Background Technology

[0002] Patent Document 1 discloses an electric vehicle comprising a first battery pack and a second battery pack constituting a battery module and a drive motor. The first battery pack and the second battery pack are connected in parallel, and a first contactor and a second contactor are provided between the first battery pack, the second battery pack and the drive motor.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2020-167864. Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Battery packs have a suitable operating temperature range. Using them below this range will reduce battery capacity or shorten battery life. Therefore, prolonged use at temperatures below the operating temperature range is not advisable. If a vehicle is parked for an extended period in low temperatures, causing the battery pack temperature to be significantly below the operating temperature range, it may take some time for the battery pack to reach the operating temperature range after the vehicle is started.

[0008] Therefore, the object of this disclosure is to provide a battery control system that, in a vehicle having multiple battery packs connected in parallel with a load, can efficiently heat up the low-temperature battery packs supplying power after power supply to the load begins.

[0009] Solution to the problem

[0010] To achieve the above objectives, the first aspect of this disclosure provides a battery control system for a vehicle, the vehicle being equipped with a battery module having multiple battery packs and the multiple battery packs being connected in parallel with a load, the battery control system for the vehicle comprising: a battery connection disconnection unit, a temperature determination unit, and a battery connection disconnection control unit.

[0011] The battery connection disconnection unit is configured to be located between the battery module and the load, enabling individual connection and disconnection of each of the multiple battery packs to the load. The temperature determination unit determines whether the temperature of the battery packs is above a predetermined minimum threshold temperature. When power is supplied from the battery module to the load, the battery connection disconnection control unit controls the battery connection disconnection unit to connect a first predetermined number of battery packs to the load if the temperature determination unit determines that the temperature of all battery packs in the multiple battery packs is above the minimum threshold temperature; otherwise, it controls the battery connection disconnection unit to connect a second predetermined number of battery packs, less than the first predetermined number, to the load if the temperature determination unit determines that the temperature of all battery packs in the multiple battery packs is below the minimum threshold temperature.

[0012] The second aspect of this disclosure is based on the battery control system of the first aspect, wherein the second specified quantity is a quantity greater than or equal to the minimum number of battery packs required for the vehicle to operate.

[0013] The third method of this disclosure is based on the battery control system of the first or second method, wherein when a portion of the battery pack is connected to the load, the battery connection disconnection control unit preferentially connects to the battery pack with the higher temperature.

[0014] Invention Effects

[0015] According to the battery control system disclosed herein, in a vehicle having multiple battery packs connected in parallel with a load, it is possible to efficiently heat up the low-temperature battery packs that supply power to the load after power supply begins. Attached Figure Description

[0016] Figure 1 This is a schematic side view of a vehicle equipped with a battery module according to one embodiment of the present disclosure.

[0017] Figure 2 It means Figure 1 A block diagram of the battery control system of the implementation method.

[0018] Figure 3 This is a flowchart representing the current control process.

[0019] Figure 4 This is a flowchart illustrating the battery pack connection / disconnection control process.

[0020] Explanation of reference numerals in the attached figures

[0021] 1: Battery module;

[0022] 2: Battery pack;

[0023] 3: Battery connection disconnection point;

[0024] 4: Load;

[0025] 5: Temperature sensor;

[0026] 6: Contactor;

[0027] 10: Battery control device;

[0028] 11: Temperature Acquisition Unit;

[0029] 12: Voltage acquisition unit;

[0030] 13: Upper limit current calculation unit;

[0031] 14: Current control unit;

[0032] 15: Temperature determination unit;

[0033] 16: Battery connection disconnection control unit. Detailed Implementation

[0034] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. The battery control system of this embodiment is installed in vehicles such as electric vehicles and hybrid vehicles.

[0035] like Figure 1 As shown, the vehicle is equipped with multiple (three in this embodiment) battery packs 2. These multiple battery packs 2 constitute the battery module 1. It should be noted that... Figure 1 The illustration shows an example of a truck with battery module 1 installed, but the vehicle is not limited to trucks.

[0036] like Figure 2 As shown, the battery control system includes: a battery module 1, a battery connection disconnection part 3, a load 4, and a battery control device 10.

[0037] Multiple battery packs 2 are connected in parallel with a load 4. Each battery pack 2 is equipped with a temperature sensor 5 to detect its temperature. The load 4 includes a drive motor (not shown) that propels the vehicle. The drive motor is powered by electricity supplied from the battery module 1.

[0038] The battery connection disconnection section 3 consists of the same number of contactors 6 as the battery pack 2, and is located between the battery module 1 and the load 4. Each of the multiple battery packs 2 is individually connected to and disconnected from the load 4 by turning the contactors 6 on and off. In this embodiment, the state where all battery packs 2 are connected to the load 4 (all contactors 6 are on) is described as the standard connection mode (normal state) of the battery connection disconnection section 3.

[0039] The battery control device 10 is, for example, an ECU (Electronic Control Unit), which includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and input / output circuits. The battery control device 10 functions as a temperature acquisition unit 11, a voltage acquisition unit 12, an upper limit current calculation unit 13, a current control unit 14, a temperature determination unit 15, and a battery connection / disconnection control unit 16 by executing a pre-stored control program.

[0040] The temperature acquisition unit 11 sequentially acquires the temperature of each battery pack 2 from the temperature sensor 5. The voltage acquisition unit 12 sequentially acquires the voltage between the terminals of each battery pack 2 (the voltage value of the battery pack 2) from the voltage sensor (not shown).

[0041] The battery control device 10 stores upper limit current value information (e.g., mapping) that represents the correspondence between the temperature and voltage values ​​of the battery pack 2 and the upper limit current value. The upper limit current value is the maximum current effective for protecting the battery pack 2; given a constant voltage, the upper limit current value decreases as the temperature rises. The battery pack 2 has a suitable operating temperature range; if the temperature rises above this range, the upper limit current value will decrease significantly. This upper limit current value information is calculated in advance through simulation or similar methods and stored in the battery control device 10.

[0042] The upper limit current calculation unit 13 uses the temperature of the battery pack 2 obtained by the temperature acquisition unit 11, the voltage value of the battery pack 2 obtained by the voltage acquisition unit 12, and the upper limit current value information to calculate the upper limit current value of each battery pack 2.

[0043] The current control unit 14 controls the current value of the battery pack 2 to be below the upper limit current value. Since the battery packs 2 are connected in parallel, the total current value flowing through the battery module 1 is evenly distributed to each battery pack 2, and the current value of each battery pack 2 is equal. The current control unit 14 controls the total current value so that the current below the smallest upper limit current value among the upper limit current values ​​of the parallel-connected battery packs 2 flows through each battery pack 2.

[0044] The battery control device 10 stores the minimum threshold temperature of the battery pack 2. The minimum threshold temperature refers to the temperature of the battery pack 2 that is below the lower limit of its operating temperature range and is likely to be a relatively long temperature that the battery pack 2 will take to heat up and reach the lower limit of its operating temperature range after power is supplied from it. The minimum threshold temperature is calculated in advance through simulation or the like and stored in the battery control device 10.

[0045] The temperature determination unit 15 compares all the temperatures of the battery pack 2 obtained by the temperature acquisition unit 11 with the minimum threshold temperature and determines whether each temperature is above the minimum threshold temperature. This determination can be performed only when power is supplied from the battery module 1 to the load 4, or it can be performed at any time (for example, whenever the temperature acquisition unit 11 acquires a temperature).

[0046] When power is supplied from battery module 1 to load 4, battery connection disconnection control unit 16 controls battery connection disconnection unit 3 to connect a first predetermined number of battery packs 2 to load 4 if temperature determination unit 15 determines that the temperature of all (three) of the multiple battery packs 2 is above the minimum threshold temperature, and if temperature determination unit 15 determines that the temperature of some (one or two) of the multiple battery packs 2 is below the minimum threshold temperature. That is, a first predetermined number of battery packs 2 are connected when the temperature of one or more battery packs 2 is equal to or higher than the minimum threshold temperature.

[0047] On the other hand, if the temperature determination unit 15 determines that the temperature of all battery packs 2 is below the minimum threshold temperature, the battery connection disconnection control unit 16 controls the battery connection disconnection unit 3 to connect a second predetermined number (first predetermined number > second predetermined number) of battery packs 2 to the load 4 in a manner that is less than the first predetermined number. When connecting the second predetermined number of battery packs 2, the battery connection disconnection control unit 16 prioritizes connecting the battery packs 2 with higher temperatures.

[0048] As a second specified quantity, a quantity greater than or equal to the minimum number of battery packs 2 required for vehicle operation is set. This second specified quantity can be a fixed value or a variable value calculated and set each time based on the vehicle's condition (e.g., load). In this embodiment, the number of connections in the normal connection mode, i.e., "3", is set as the first specified quantity. Furthermore, the minimum number of battery packs 2 required for vehicle operation is two, and "2" is set as the second specified quantity (fixed value).

[0049] It should be noted that if the temperature determination unit 15 determines that the temperature of a portion (one or two) of the multiple battery packs 2 is below the minimum threshold temperature, the battery connection disconnection unit 3 can also be controlled by connecting a second predetermined number of battery packs 2 to the load 4.

[0050] Next, refer to Figure 3 and Figure 4The flowchart below explains the current control processing and battery pack 2 connection / disconnection control processing performed by the battery control device 10. The battery control device 10 repeatedly performs current control processing during the period when power is supplied from the battery module 1 to the load 4. Additionally, the battery control device 10 performs battery pack 2 connection / disconnection control processing when power supply from the battery module 1 to the load 4 begins (e.g., when the vehicle's power is turned on). It should be noted that, in order to obtain the voltage values ​​of all battery packs 2, the battery control device 10 connects all battery packs 2 to the load 4 before the connection / disconnection control processing (setting the connection / disconnection unit 3 to the standard connection mode).

[0051] like Figure 3 As shown, in the current control process, the temperature and voltage values ​​of the three battery packs 2 are obtained respectively (step S1), and the upper limit current value of each battery pack 2 is calculated using the obtained temperature and voltage values ​​and upper limit current value information of the battery pack 2 respectively (step S2).

[0052] After calculating the upper limit current values ​​of the three battery packs 2, the total current value of the battery module 1 is controlled in such a way that the current equal to or lower than the smallest of the calculated upper limit current values ​​flows through each battery pack 2 (step S3).

[0053] like Figure 4 As shown, in the connection disconnection control process, the temperatures of the three battery packs 2 are obtained (step S11), and it is determined whether the obtained temperature of the battery pack 2 is above the minimum threshold temperature (step S12).

[0054] If the temperature of at least one of the three battery packs 2 is determined to be above the minimum threshold temperature, the battery connection disconnection unit 3 is controlled to connect the three battery packs 2 to the load 4. On the other hand, if the temperature determination unit 15 determines that the temperature of all three battery packs 2 is below the minimum threshold temperature, the battery connection disconnection unit 3 is controlled to connect the two battery packs 2 with higher temperatures to the load 4.

[0055] In this embodiment, when power is supplied from battery module 1 to load 4, if the temperature of all battery packs 2 is below the minimum threshold temperature, a second predetermined number (two) of battery packs 2, less than the first predetermined number (three) normally connected, is connected to load 4. That is, the number of connected battery packs 2 is reduced from three to two. Comparing the case where the number of connected battery packs 2 is three and the case where it is two, the current flowing through each battery pack 2 is greater when the number of connected battery packs 2 is two than when the number of connected battery packs 2 is three, and the temperature rise rate of each battery pack 2 due to its internal resistance is faster. Therefore, for example, when the vehicle is parked at low temperature for a long time and the temperature of all battery packs 2 has dropped below the minimum threshold temperature, the low-temperature battery packs 2 supplied with power can be heated efficiently after power supply to load 4 begins, and the time it takes for the temperature of the battery packs 2 to reach the operating temperature range can be shortened.

[0056] Since the second specified quantity is more than the minimum number of battery packs 2 required for the vehicle to run, even if the number of battery packs 2 connected is reduced, the vehicle can still run at a minimum.

[0057] In addition, when a portion of battery pack 2 is connected to the load, the battery pack 2 with higher temperature is connected first. Therefore, compared with the case of connecting the battery pack 2 with lower temperature, the time to reach the operating temperature range can be shortened.

[0058] The present disclosure has been described above based on the aforementioned embodiments, but the present disclosure is not limited to the content of the above embodiments, and of course, appropriate modifications can be made without departing from the scope of the present disclosure. That is, other embodiments, examples, and application techniques implemented by those skilled in the art based on the embodiments are all included in the scope of the present disclosure.

[0059] For example, in the above embodiment, an example was described where a battery module 1 is composed of three battery packs 2, and all three (all) battery packs 2 are connected in parallel with the load 4 in the normal state. However, the number of battery packs 2 constituting the battery module 1 is not limited to the above description, and any number is acceptable. Alternatively, some of the battery packs 2 may be connected to the load 4 in the normal state.

[0060] Industrial applicability

[0061] This disclosure can be applied to vehicles having multiple battery packs connected in parallel with the load.

Claims

1. A battery control system for a vehicle, the vehicle being equipped with a battery module having multiple battery packs connected in parallel with a load, the battery control system for the vehicle being characterized by comprising: A battery connection disconnection section, located between the battery module and the load, is capable of individually connecting and disconnecting each of the plurality of battery packs from the load; The temperature determination unit determines whether the temperature of each of the plurality of battery packs is above a specified minimum threshold temperature. as well as The battery connection disconnection control unit, when starting to supply power from the battery module to the load, controls the battery connection disconnection unit to connect a first predetermined number of battery groups to the load if the temperature determination unit determines that the temperature of at least one battery group among the plurality of battery groups is above the minimum threshold temperature; and controls the battery connection disconnection unit to connect a second predetermined number of battery groups, less than the first predetermined number, to the load if the temperature determination unit determines that the temperature of all battery groups among the plurality of battery groups is below the minimum threshold temperature. When the second specified number of battery packs are connected to the load, the battery connection disconnection control unit preferentially connects the battery packs with higher temperatures.

2. The vehicle battery control system as described in claim 1, characterized in that, The second specified quantity is calculated and set according to the state of the vehicle, and is a quantity greater than or equal to the minimum number of battery packs required for the vehicle to operate.

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