CN218783115U

CN218783115U - Battery thermal runaway prevention system

Info

Publication number: CN218783115U
Application number: CN202222530342.7U
Authority: CN
Inventors: 易如清
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-09-23
Filing date: 2022-09-23
Publication date: 2023-03-31
Anticipated expiration: 2032-09-23

Abstract

The system for preventing thermal runaway of the battery comprises a battery pack formed by connecting a plurality of modules in series, wherein each module is provided with a relatively independent cooling unit, the cooling units are respectively provided with valves, the system further comprises an air conditioning system, a liquid storage tank and a pump, the pump conveys cooling liquid to the cooling units and the cooling units circulate through the air conditioning system, and the system further comprises a battery management unit which respectively monitors each module and controls the opening and closing of a valve; the module of series connection divide into two parts, is equipped with the contactor, and the C terminal of the preceding module of module, the D terminal of back module are connected to the contactor, still include the connecting rod of swing joint C terminal and D terminal, and air conditioning system includes D1 terminal and C1 terminal, and the connecting rod includes three with each terminal connection state: C-D, C-C1, D-D1. This system is when the impaired and possible spontaneous combustion of electric core, cuts off load circuit, switch-on air conditioning system circuit, and the switching process is done to the contactor simultaneously, and partial module is for air conditioning system power supply to cooling unit to having the impaired module of electric core cools down, avoids the emergence of battery package spontaneous combustion condition.

Description

Battery thermal runaway prevention system

Technical Field

The utility model relates to a battery field exactly indicates a prevention system out of control who takes place unusual intensification in the battery use.

Background

At present, the batteries are the biggest bottleneck restricting the development of the electric vehicles. The grouping mode of the current power battery pack (not limited to lithium battery cells) has 2 types: 1. the parallelly connected capacity that improves of little electric core, then the series connection forms the module, is established ties together by a plurality of modules at last and becomes power battery package. Typical power packs are, for example, the 18650 and 21700 power packs of Tesla. 2. A plurality of big electric cores establish ties earlier and become the module, then a plurality of modules establish ties again and become power battery package. The purpose of forming the module here is for management convenience. Early ningde and biddi were so grouped. In the prior art, the new energy automobile has frequent spontaneous combustion and ignition events, and spontaneous combustion can occur under several conditions.

1) During a traffic accident, the battery core in the battery pack is extruded and seriously deformed, so that the internal short circuit of part of the battery core is caused, and the internal temperature is higher and higher to cause thermal runaway.

2) When general charging or heavy current charge, the great or inside little short circuit that has taken place of individual electric core internal resistance, this electricity core must generate heat more, if can not in time cool down, also can lead to thermal runaway.

3) The process of traveling is kind, and little short circuit has taken place for a certain electricity core inside, and when little short circuit becomes the short circuit, inside generates heat more badly, then causes thermal runaway.

4) During parking, even if the vehicle stops in the garage after driving, if a certain electric core is internally subjected to micro short circuit and serious, the internal self-discharge current can be large, and thermal runaway can also be caused.

The reasons for the internal micro short circuit of the battery core are many: the method mainly comprises the steps that lithium dendrites caused by lithium precipitation penetrate through a diaphragm to cause short circuit, impurities in positive and negative electrode materials penetrate through the diaphragm to cause short circuit, burrs on copper foils or aluminum foils of positive and negative electrode fluids penetrate through the diaphragm to cause short circuit, the diaphragm contracts and deforms to cause direct contact of the positive and negative electrodes, and the like.

When the battery management system BMS finds that a certain cell is abnormal (e.g., the internal temperature is too high, or the power failure of the cell is severe), the cell should be stripped, and the stripping means electrical stripping, that is, the cell does not participate in the battery pack work any more. However, if the battery cell is connected in series in the power battery pack, the direct disconnection may cause the battery pack to be completely disconnected from the load circuit, which is certainly undesirable for the designer of the entire vehicle system. When the abnormal battery core is at high temperature and can be spontaneously combusted, the owner of the vehicle is still stranded, and the vehicle can only hope that the fire-fighting troops can catch up in time or the spontaneous combustion of the pray cannot occur. The existing electric automobile power supply lacks a battery thermal runaway prevention system.

SUMMERY OF THE UTILITY MODEL

The utility model provides a battery thermal runaway prevention system.

The system for preventing the thermal runaway of the battery comprises a battery pack formed by connecting a plurality of modules in series, wherein each module is provided with a relatively independent cooling unit, the cooling units are respectively provided with a valve, the system further comprises an air conditioning system, a liquid storage tank and a pump, the pump conveys cooling liquid to the cooling units and the cooling units circulate through the air conditioning system, and the system further comprises a battery management unit, and the battery management unit monitors each module and controls the opening and closing of a valve respectively;

the module of establishing ties divide into two parts, is equipped with a contactor between, and the contactor includes the C terminal of the preceding module of intermediate junction module, the D terminal of back module, still includes the connecting rod of swing joint C terminal and D terminal, and air conditioning system includes D1 terminal and C1 terminal, and the connecting rod includes three kinds with each terminal connection status: C-D, C-C1 and D-D1.

Preferably, the valve is a solenoid valve.

Preferably, the contactor is located in the middle of the series of modules.

Preferably, the battery pack is further connected with a load, a switch K is connected with the battery pack, the load is connected with the air conditioning system in parallel and is connected through a switch Ki, the battery management unit controls one of the switch K and the switch Ki to be disconnected from the other, the switch K is closed to be connected with the load to work when the connection state of the connecting rod is C-D, and the switch Ki is closed to be connected with the air conditioning system to work when the connection state of the connecting rod is C-C1 or D-D1.

The utility model discloses a system reach the battery package in the control analysis and have electric core impaired and probably to be the switching process when leading to taking place battery package spontaneous combustion, load circuit cuts off, switch-on air conditioning system circuit, the switching process is done to the contactor simultaneously, make that partial module that has electric core impaired open circuit, the power supply of air conditioning system is given to the module that the state is good, and open the valve of the cooling unit that has the impaired module of electric core, let the coolant liquid carry out cooling to this module, avoid the emergence of battery package spontaneous combustion condition.

Drawings

Fig. 1 is a schematic diagram of a battery thermal runaway prevention system.

Fig. 2 is a schematic diagram of the connection between the battery module and the air conditioning system.

Fig. 3 is a circuit diagram of the control pump and air conditioning system in the battery management unit.

Fig. 4 is a circuit diagram of a battery pack monitoring circuit in the battery management unit.

Fig. 5 is a circuit diagram of a single chip in the battery management unit.

Detailed Description

The present invention will be further described with reference to the following examples.

As shown in fig. 1, the system for preventing thermal runaway of battery of the present application comprises a battery pack formed by connecting a plurality of modules in series, for example, four modules 10 are shown in the figure, wherein each module 10 has a relatively independent cooling unit 20, the cooling unit 20 is a box for placing the battery module and is provided with a valve 21, and a solenoid valve is selected here; the cooling system further comprises an air conditioning system 30, a liquid storage tank 40 and a pump 50, wherein the pump 50 conveys cooling liquid in the liquid storage tank 40 to the cooling unit 20 for cooling and then circulates through the air conditioning system 30, and the battery management unit 60 is used for respectively monitoring the opening and closing of each module 10 and each control valve 21; referring to fig. 2 to 5 again, the series module 10 is divided into two parts, a contactor 1 is arranged in the middle, the contactor 1 includes a C terminal of a front module of the middle connection module 10, a D terminal of a rear module, and a connecting rod 2 movably connecting the C terminal and the D terminal, the air conditioning system 30 includes the D1 terminal and the C1 terminal, and the connecting rod 2 and each terminal are connected in three states: the battery pack is further connected with a load 70, the connecting circuit is provided with a switch K, the load 70 is connected with the air conditioning system 30 in parallel and is connected through a switch Ki, the battery management unit 60 also controls the switch K and the switch Ki at the same time, when the connecting state of the connecting rod 2 is C-D, the switch K is closed to connect the load 70 to work, and when the connecting state of the connecting rod 2 is C-C1 or D-D1, the switch Ki is closed to connect the air conditioning system 30 to work. For example, when an electric vehicle is running, when a certain electric core in a battery pack is in a fault and causes a short circuit (micro short circuit), the temperature is rapidly raised, here, the battery management unit 60 monitors the running condition of the battery, when the temperature measured by the temperature sensor (RT 1-RT4 in fig. 4) is raised too fast within a specified time or reaches a certain rated value, it is determined that the electric core in a certain module is damaged, and a signal of K _ OUT is controlled to control opening and closing of K1 (relay), at this time, the battery management unit 60 cuts off a working circuit of the load 70 (turns off the switch Ki), turns on a working circuit of the air conditioning system 30 and a working circuit of the pump 50 (turns on the switch K), for example, it is determined that the electric core in a second module is damaged, the valve 21 of the cooling unit of the module is simultaneously opened, at this time, the air conditioning system 30 operates, the pump 50 delivers the cooling liquid to the cooling unit 20 for cooling, the module without the electric core fault does not perform cooling, and the cooling liquid after heat exchange is delivered back to the air conditioning system 30 for cooling.

The system provided by the application can make a judgment in advance when a battery cell breaks down and possibly causes spontaneous combustion of a battery pack (vehicle), the working state of a module of a damaged battery cell is closed, the working state of a load is closed, the other part of the module continues to supply electric energy and starts an air conditioning system to work, (generally speaking, a contactor 1 is selected in the middle, no matter which battery cell is damaged, the voltage change after switching is basically ensured to be not large, the influence of the voltage reduction after switching on the air conditioning system is avoided, the voltage reduction after switching can be realized through other boosting circuits and the like, which is not the key point of the discussion in the application and is not repeated here), the module where the damaged battery cell is located is cooled and cooled, the damaged high-temperature module can be cooled to the greatest extent, spontaneous combustion is avoided or the time of dangerous occurrence is prolonged to the greatest extent, so that people in a vehicle can withdraw as soon as possible, the most reasonable processing is carried out in striving for time, and insurance personnel and property safety are ensured.

The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.

Claims

1. A battery thermal runaway prevention system comprises a battery pack formed by connecting a plurality of modules in series, and is characterized in that each module is provided with a relatively independent cooling unit, each cooling unit is provided with a valve, the battery pack further comprises an air conditioning system, a liquid storage tank and a pump, the pump conveys cooling liquid to the cooling unit and the cooling unit circulates through the air conditioning system, and the battery pack further comprises a battery management unit, and the battery management unit monitors each module and controls the valve to be switched on and off respectively;

the module of establishing ties divide into two parts, is equipped with a contactor between, the contactor includes the C terminal of the preceding module of intermediate junction module, the D terminal of back module, still includes the connecting rod of swing joint C terminal and D terminal, air conditioning system includes D1 terminal and C1 terminal, the connecting rod includes three with each terminal connection state: C-D, C-C1 and D-D1.

2. The battery thermal runaway prevention system of claim 1, wherein the valve is a solenoid valve.

3. The system of claim 1, wherein the contactor is disposed in the middle of the series of modules.

4. The system for preventing thermal runaway of a battery according to claim 1, wherein the battery pack is further connected to a load, and a switch K is connected to the battery pack, wherein the load is connected to the air conditioning system in parallel and is connected to the battery pack through a switch Ki, the battery management unit controls one of the switch K and the switch Ki to be disconnected from the other, the switch K closes the connection of the load to operate when the connection state of the connection bar is C-D, and the switch Ki closes the air conditioning system to operate when the connection state of the connection bar is C-C1 or D-D1.