Power supply circuit of power battery cooling system and power battery system

Abstract

The present invention relates to the technical field of power batteries, and provides a power supply circuit of a power battery cooling system, a power battery system, and a method for handling thermal runaway of a power battery. The cooling system cools and dissipates heat from the power battery of an electric vehicle when the power battery is in a thermal runaway state. The cooling system is powered by a whole vehicle battery of the electric vehicle, and the power supply circuit includes a relay module; the relay module includes at least one relay group, and at least one battery module of the power battery is connected to the input end of the whole vehicle battery through the relay group, so that the battery module directly charges the whole vehicle battery. The present invention controls the battery module to directly supply power to the whole vehicle battery through the relay module. When the power battery is in thermal runaway and the main positive and negative relays are not allowed to close, the whole vehicle battery can be continuously powered to ensure the sustainable supply of power to the electronic water pump of the cooling system.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a power supply circuit of a power battery cooling system, a power battery system and a method for processing thermal runaway of a power battery. Background Art

[0002] When the power battery of an electric vehicle experiences thermal runaway, it first occurs in the single cell, then slowly spreads, and eventually causes thermal runaway of the entire battery pack, escalating to a serious accident of the entire vehicle. How to ensure that after the thermal runaway of a single cell, the heat generated inside the battery can be quickly transferred to the outside of the battery pack, so that the heat generation rate of the battery pack is lower than the heat dissipation rate, and heat is not accumulated inside the battery pack, is the key to ensuring that subsequent cells and modules, or even the entire battery pack, do not catch fire or explode.

[0003] In the prior art, the method of achieving rapid heat exchange between the battery pack and the outside world is: after detecting that the battery pack has reached the thermal runaway warning judgment condition, the BMS (battery management system) reports the warning signal to the VCU (vehicle control unit), and the VCU controls the vehicle to force the water cooling cycle to dissipate the heat of the battery pack. The cooling circuit of the battery pack is composed of a radiator, an electronic water pump, a cooling pipe, etc. The electronic water pump is driven by a motor (power of about 150W) to provide power for the coolant circulation, and the motor of the electronic water pump is powered by a 12V vehicle battery. The defect of the prior art is that when the power battery has a thermal runaway warning, the main positive and negative relays will not be allowed to close, and the power battery cannot power the vehicle battery through the DC / DC module. If the vehicle battery is in a low-power state or a low SOC state at this time, the operation time of the electronic water pump cannot be guaranteed or even the electronic water pump cannot be started. Usually, when the battery pack reaches the thermal runaway judgment condition, if the forced water cooling cycle can be maintained for more than 1 hour and no other cells in the battery system lose control, it can be judged that the external water cooling intervention has enabled the battery system to reach thermal balance, that is, the heat generated by the battery can be effectively transferred out and will not cause other cells to lose control later. When the vehicle battery is in a low-power state, the coolant circulation cannot be maintained for a long time or even the coolant circulation system cannot be started, and the heat dissipation problem when the battery pack is in thermal runaway cannot be completely solved. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a power supply circuit of a power battery cooling system and a power battery system to solve the above-mentioned problems.

[0005] In order to achieve the above-mentioned objectives, the first aspect of the present invention provides a power supply circuit of a power battery cooling system, wherein the cooling system cools and dissipates heat for the power battery of an electric vehicle when the power battery is in a thermal runaway state, and the cooling system is powered by a vehicle battery of the electric vehicle, and the power supply circuit includes a relay module; the relay module includes at least one relay group, and at least one battery module of the power battery is connected to the input end of the vehicle battery through the relay group, so that the battery module can directly charge the vehicle battery.

[0006] Optionally, the relay module includes N relay groups, and the N battery modules of the power battery are respectively connected to the input end of the vehicle battery through corresponding relay groups. At the same time, only one of the N relay groups is in a closed state, where N≥2 and is an integer.

[0007] Optionally, the power supply circuit further includes a connector, and the N relay groups are connected to the vehicle battery via the connector.

[0008] Optionally, the relay group includes two relays, the positive pole of the battery module is connected to the negative pole of the input terminal of the vehicle battery through one relay of the relay group, and the negative pole of the battery module is connected to the positive pole of the input terminal of the vehicle battery through another relay of the relay group.

[0009] The power supply circuit of the power battery cooling system provided by the present invention controls the battery module through a relay module to directly supply power to the whole vehicle battery. When the power battery thermal runaway occurs and the main positive and negative relays are not allowed to close, it can continuously supply power to the 12V whole vehicle battery to ensure the sustainable power supply of the electronic water pump of the cooling system.

[0010] A second aspect of the present invention provides a power battery system, comprising:

[0011] A battery management system, used to collect voltage parameters and temperature parameters of a power battery, and determine whether the power battery is in thermal runaway according to the voltage parameters and the temperature parameters;

[0012] a cooling system, used for cooling and dissipating the power battery when the power battery is in thermal runaway, the cooling system being powered by a vehicle battery of the electric vehicle; and

[0013] The power supply circuit of the power battery cooling system is used to directly charge the vehicle battery.

[0014] Optionally, the battery management system includes a main board and a slave board, and the main board is signal-connected to a relay module of a power supply circuit of the power battery cooling system.

[0015] Optionally, the cooling system includes an electronic water pump for pumping coolant, the output end of the vehicle battery is connected to the electronic water pump, and the electronic water pump is powered by the vehicle battery.

[0016] The power battery system provided by the present invention, through the power supply circuit of the power battery cooling system, can continuously supply power to the battery of the entire vehicle when the battery pack reaches the thermal runaway warning judgment condition or even when the single battery cell of the battery pack is in thermal runaway, thereby achieving uninterrupted power supply to the 12V vehicle battery, solving the problem of insufficient power supply for the cooling system, and completely solving the heat dissipation problem when the battery pack is in thermal runaway.

[0017] A third aspect of the present invention provides a method for handling thermal runaway of a power battery. Based on the above power battery system, the method comprises:

[0018] When the power battery is in thermal runaway, the battery management system is used to determine the abnormal battery module and the normal battery module;

[0019] Sending a relay closing instruction to a relay group connected to the normal battery module through the battery management system;

[0020] The normal battery module is used to continuously charge the battery of the entire vehicle, the battery of the entire vehicle is used to power the electronic water pump of the cooling system, and the cooling system is used to cool and dissipate heat for the power battery.

[0021] Furthermore, the battery management system determines the abnormal battery module and the normal battery module when the power battery has thermal runaway, including: the battery management system determines the abnormal single cell based on the voltage parameters, temperature parameters of the single cell collected from the board and the pressure change information in the battery pack, thereby determining the abnormal battery module.

[0022] Furthermore, the method also includes: sending a thermal runaway alarm signal to a vehicle controller through the battery management system.

[0023] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0025] Figure 1 is a schematic diagram of a power supply circuit of a power battery cooling system provided in Embodiment 1 of the present invention;

[0026] Figure 2 is a schematic diagram of a power battery system provided by Embodiment 2 of the present invention;

[0027] Figure 3 It is a flow chart of a method for handling thermal runaway of a power battery provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0029] In the embodiments of the present invention, the terms "first", "second", "third", etc. are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance. The "connection" described herein is used to describe the electrical power connection or signal connection between two components / elements; the "connection" can be a direct connection between two elements, or can be connected through an intermediate medium (such as a wire), or can be an indirect connection achieved through a third element.

[0030] Embodiment 1

[0031] Figure 1 Schematic diagram of the power supply circuit of the power battery cooling system provided by the first embodiment of the present invention. Figure 1As shown, this embodiment provides a power supply circuit of a power battery cooling system, wherein the cooling system cools and dissipates the power battery when the power battery of the electric vehicle is in a thermal runaway state, and the cooling system is powered by the whole vehicle battery of the electric vehicle. The power supply circuit includes a relay module, and the relay module includes at least one relay group. At least one battery module of the power battery is connected to the input end of the whole vehicle battery through the relay group, so that the battery module directly charges the whole vehicle battery. The relay group includes two relays, and the positive electrode of the battery module is connected to the negative electrode of the whole vehicle battery through one relay of the relay group, and the negative electrode of the battery module is connected to the positive electrode of the whole vehicle battery through another relay of the relay group. In this embodiment, the power battery includes five battery modules, and the relay module includes a first relay group and a second relay group. The first relay group includes relays K1 and K2, and the negative electrode of the fifth battery module is connected to the positive electrode of the input end of the whole vehicle battery through relay K1, and the positive electrode of the fifth battery module is connected to the negative electrode of the input end of the whole vehicle battery through relay K2. The second relay group includes relay K3 and relay K4. The positive pole of the first battery module is connected to the negative pole of the vehicle battery input terminal through relay K3, and the negative pole of the first battery module is connected to the positive pole of the vehicle battery input terminal through relay K4. At the same time, one of the first relay group and the second relay group is in a closed state, and the other is in an open state. For example, if the battery cell of any one of the first battery module, the second battery module, the third battery module, and the fourth battery module is abnormal, the second relay group is disconnected, the first relay group is closed, and the battery of the whole vehicle is powered by the fifth battery module; if the battery cell of the fifth battery module is abnormal, the first relay group is disconnected, the second relay group is closed, and the battery of the whole vehicle is powered by the first battery module.

[0032] Optionally, the relay module includes N relay groups, and the N battery modules of the power battery are respectively connected to the input end of the vehicle battery through the corresponding relay groups, and only one of the N relay groups is in a closed state, where N ≥ 2 and is an integer. For example, the power battery includes five battery modules, namely the first battery module, the second battery module, the third battery module, the fourth battery module, and the fifth battery module; the relay module includes five relay groups, namely the first relay group, the second relay group, the third relay group, the fourth relay group, and the fifth relay group. The first battery module, the second battery module, the third battery module, the fourth battery module, and the fifth battery module are respectively connected to the first relay group, the second relay group, the third relay group, the fourth relay group, and the fifth relay group. At the same time, only one of the five relay groups can be in a closed state, and the other four are in a disconnected state. When the power battery has thermal runaway, if the second battery module is abnormal, the second relay group will be disconnected and the third relay group will be closed; if the third battery module is also abnormal, the third relay group will be disconnected and the fourth relay group will be closed. This principle is used to control the opening and closing of each relay group.

[0033] In a preferred embodiment, the power supply circuit further includes a connector, and the N relay groups are connected to the vehicle battery through the connector. For example, the connector is set in the power battery pack, and the connector includes multiple input interfaces and multiple corresponding output interfaces. The multiple relay groups are respectively connected to the input interfaces of the connector through wires, and the output interfaces of the connector are connected to the input end of the vehicle battery through a flat cable.

[0034] The power supply circuit of the power battery cooling system provided in this embodiment controls the battery module through the relay module to directly supply power to the whole vehicle battery. When the power battery has thermal runaway and the main positive and negative relays are not allowed to close, it can continuously supply power to the 12V whole vehicle battery to ensure the sustainable power supply of the electronic water pump of the cooling system.

[0035] Embodiment 2

[0036] Figure 2 Schematic diagram of the power battery system provided by the second embodiment of the present invention. Figure 2As shown, this embodiment provides a power battery system, including a battery management system, a cooling system, and a power supply circuit of the power battery cooling system described in Example 1. The battery management system is used to collect voltage parameters and temperature parameters of the power battery, and determine whether the power battery is in thermal runaway according to the voltage parameters and the temperature parameters. The cooling system is used to cool and dissipate heat from the power battery when the power battery is in thermal runaway, and the cooling system is powered by the vehicle battery of the electric vehicle. The power supply circuit of the power battery cooling system is used to directly charge the vehicle battery. Specifically, the cooling system includes an electronic water pump for pumping coolant, the output end of the vehicle battery is connected to the electronic water pump, and the electronic water pump is powered by the vehicle battery.

[0037] In this embodiment, the battery management system includes a main board and a slave board, the slave board is used to collect voltage parameters and temperature parameters of the single cells of the power battery, and the main board is used to analyze whether the power battery is in thermal runaway according to the pressure change information in the battery pack and the voltage parameters and temperature parameters collected by the slave board. The main board is connected to the relay module signal of the power supply circuit of the power battery cooling system to transmit a control signal to the relay module to control the opening or closing of each relay in the relay module.

[0038] It should be noted that when the vehicle is operating normally, the power supply circuit is in a disconnected state (that is, all relays are in a disconnected state). Only when the battery management system determines that the battery has reached the thermal runaway warning judgment condition will the relay be forced to close, thereby connecting the power supply circuit between the battery module and the vehicle battery.

[0039] The power battery system provided in this embodiment, through the power supply circuit of the power battery cooling system, can continuously supply power to the battery of the entire vehicle when the battery pack reaches the thermal runaway warning judgment conditions or even when the single battery cell of the battery pack is in thermal runaway, so as to achieve uninterrupted power supply to the 12V vehicle battery, solve the problem of insufficient power supply of the cooling system, and completely solve the heat dissipation problem when the battery pack is in thermal runaway.

[0040] Embodiment 3

[0041] Figure 3 : is a flow chart of a method for handling thermal runaway of a power battery provided in Embodiment 3 of the present invention. Figure 3 As shown, this embodiment provides a method for handling thermal runaway of a power battery. Based on the power battery system described in the second embodiment, the method includes:

[0042] S1. When the power battery is in thermal runaway, the abnormal battery module and the normal battery module are determined by the battery management system.

[0043] Specifically, the battery management system determines the abnormal single cell according to the voltage parameters and temperature parameters of the single cell collected from the board and the pressure change information in the battery pack, thereby determining the abnormal battery module.

[0044] S2. Sending a relay closing instruction to the relay group connected to the normal battery module through the battery management system.

[0045] S3. Continuously charge the vehicle battery through the normal battery module, power the electronic water pump of the cooling system through the vehicle battery, and cool the power battery through the cooling system.

[0046] In this embodiment, the method for handling thermal runaway of a power battery also includes: sending a thermal runaway alarm signal to the vehicle controller through the battery management system. When the vehicle controller receives the thermal runaway warning signal from the mainboard of the battery management system, it determines the status of the vehicle, sends an alarm prompt message to the instrument control unit, sends the status of the vehicle to the remote data center, and instructs the next operation of the vehicle. The instrument control unit executes the instructions issued by the vehicle controller, and notifies the driver and passengers to evacuate immediately through sound, text, signal lights, etc. The remote data center transmits the thermal runaway warning information to the Fengyun platform via a wireless network. Based on the received warning information, the Fengyun platform identifies risks and prompts before a fault occurs, and notifies the owner and the fire department after the fault occurs.

[0047] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0048] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, the technical solutions of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. In addition, the various implementation modes of the embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. A power supply circuit of a power battery cooling system, wherein the cooling system cools and dissipates heat from the power battery of an electric vehicle when the power battery is in a thermal runaway state, and the cooling system is powered by a vehicle battery of the electric vehicle, characterized in that: The power supply circuit includes a relay module; The relay module includes N relay groups, and the N battery modules of the power battery are respectively connected to the input end of the vehicle battery through the corresponding relay groups, so that the battery module directly charges the vehicle battery; at the same time, only one of the N relay groups is in a closed state, where N ≥ 2 and is an integer; A relay group includes two relays. The positive pole of a battery module of the power battery is connected to the negative pole of the input end of the vehicle battery through one relay of the relay group, and the negative pole of the battery module is connected to the positive pole of the input end of the vehicle battery through another relay of the relay group.

2. The power supply circuit of the power battery cooling system according to claim 1, characterized in that: The power supply circuit also includes a connector, and the N relay groups are connected to the vehicle battery via the connector.

3. A power battery system, characterized in that: include: A battery management system, used to collect voltage parameters and temperature parameters of a power battery, and determine whether the power battery is in thermal runaway according to the voltage parameters and the temperature parameters; a cooling system, used for cooling and dissipating the power battery when the power battery is in thermal runaway, the cooling system being powered by a vehicle battery of the electric vehicle; and The power supply circuit of the power battery cooling system according to claim 1 or 2 is used to directly charge the vehicle battery.

4. The power battery system according to claim 3, characterized in that: The battery management system includes a main board and a slave board, and the main board is signal-connected to a relay module of a power supply circuit of the power battery cooling system.

5. The power battery system according to claim 4, characterized in that: The cooling system comprises an electronic water pump for pumping coolant, the output end of the vehicle battery is connected to the electronic water pump, and the electronic water pump is powered by the vehicle battery.

6. A method for handling thermal runaway of a power battery, based on the power battery system according to claim 5, characterized in that: The method comprises: When the power battery is in thermal runaway, the battery management system is used to determine the abnormal battery module and the normal battery module; Sending a relay closing instruction to a relay group connected to the normal battery module through the battery management system; The normal battery module is used to continuously charge the battery of the entire vehicle, the battery of the entire vehicle is used to power the electronic water pump of the cooling system, and the cooling system is used to cool and dissipate heat for the power battery.

7. The method for handling thermal runaway of a power battery according to claim 6, characterized in that: The battery management system determines an abnormal battery module and a normal battery module when the power battery is in thermal runaway, including: The battery management system determines the abnormal single cell according to the voltage parameters and temperature parameters of the single cell collected from the board and the pressure change information in the battery pack, thereby determining the abnormal battery module.

8. The method for processing thermal runaway of a power battery according to claim 6, characterized in that: The method further comprises: The battery management system sends a thermal runaway alarm signal to the vehicle controller.

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