CN217545581U

CN217545581U - Battery heating protection circuit

Info

Publication number: CN217545581U
Application number: CN202221316232.4U
Authority: CN
Inventors: 张琴; 牟丽莎; 杨晓琴; 尹福利
Original assignee: Chongqing Changan New Energy Automobile Technology Co Ltd
Current assignee: Deep Blue Automotive Technology Co ltd
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-10-04
Anticipated expiration: 2032-05-30

Abstract

The utility model discloses a battery heating protection circuit, include: the heating device comprises a heating main loop and a control loop for controlling the on-off of the heating main loop; the heating main loop comprises: the battery heating device comprises a battery, a heating relay, a heating element, a heat conduction element and a thermosensitive element, wherein the heat conduction element is used for heating the battery and wrapping the heating element, and the thermosensitive element is close to the heat conduction element; the control loop includes: a temperature sensor for detecting a temperature of the battery; the battery control system is used for receiving the temperature sensor and is connected with the heating relay, and when the temperature of the battery exceeds a limit value, the battery control system controls the heating relay to disconnect the heating main loop. The utility model discloses series connection temperature sensing switch in the battery heating main circuit, when battery heating control circuit became invalid or the relay adhesion, can effectual disconnection battery heating circuit, play the function of battery heating protection. The battery heating protection circuit has the advantages of complete function, simple structure, reliable use and easy control of cost.

Description

Battery heating protection circuit

Technical Field

The utility model relates to a new energy automobile battery safety technical field, in particular to battery heating protection circuit.

Background

The lithium battery is widely used on new energy automobiles at present, the reaction rate of the electrode of the lithium battery is reduced in a low-temperature environment, and the charging and discharging current and power of the lithium battery are also obviously reduced. In order to ensure the performance of the battery, the battery is heated when the temperature of the battery is too low; when the target temperature is reached, the battery heating system needs to be shut down. In general, the battery heating circuit can be disconnected by sending a signal through a battery management system; in extreme cases, however, it may happen that the battery heating circuit cannot be disconnected, causing the battery to continue to heat up, thereby increasing the risk of thermal runaway.

Many attempts have been made by the skilled person to address the above state of the art.

Patent document CN202011169625.2 discloses a power battery heating protection circuit, method and device, which attempt to solve the problem that a battery heating relay is stuck and a heating main circuit cannot be disconnected. The disclosed battery heating protection measure is that a field effect tube (electronic switch) is connected in series on a battery heating main circuit, and the heating circuit can be closed by disconnecting the field effect tube under the condition that a heating relay is adhered, so that the reliability of the battery heating circuit is improved. However, the field effect transistor in the scheme depends on a controller signal, and when the field effect transistor cannot be disconnected due to the fact that the controller has a problem, the battery is heated, and the thermal runaway risk exists.

Patent document CN209592270U discloses a power battery heating protection device, which increases the reliability of a control circuit by connecting a thermosensitive element in series with a relay control circuit (the thermosensitive element is arranged at the highest point of the heating film temperature). The concrete expression is as follows: when the battery management unit (temperature sensor and software control) fails and the temperature of the heating film rises to reach the disconnection temperature of the thermosensitive element, the thermosensitive element automatically disconnects the control loop, and then the relay is disconnected to close the heating main circuit. The battery heating relay has the defects that when the battery heating relay is adhered, the heating main loop cannot be disconnected, and the battery still has the thermal runaway risk.

SUMMERY OF THE UTILITY MODEL

Solve the problem that heating circuit can't break off and lead to thermal runaway among the battery heating process for fundamentally, the utility model provides a power battery heating protection circuit can solve the battery heating thermal runaway problem that the disconnection of battery heating circuit became invalid (temperature sensor became invalid, relay adhesion or battery control unit card die etc.) arouses.

In the field of new energy automobiles, batteries exist in the form of battery modules, and the battery modules are formed by battery cores. The electric core is the minimum unit of the power battery and is also an electric energy storage unit, and the electric core has higher energy density to store electric energy as much as possible, so that the electric automobile has longer endurance mileage. When a plurality of electric cores are packaged together by the same shell frame, and contact is carried out with the outside through unified boundary, a module is formed. Such as the 350 module, 390 module, 590 module, etc., on the market.

A vehicle battery heating protection circuit, include: the heating device comprises a heating main loop and a control loop used for controlling the on-off of the heating main loop.

The heating main loop comprises: the heating device comprises a battery, a heating relay, a heating element, a heat conduction element and a heat sensitive element, wherein the heat conduction element is used for heating the battery and wrapping the heating element, the heat sensitive element is close to the heat conduction element, and the heat sensitive element is used for disconnecting the heating main loop when the temperature of the heat conduction element exceeds a limit value.

The control loop includes: a temperature sensor for detecting a temperature of the battery; and the battery control system is used for receiving the temperature sensor and is connected with the heating relay, and when the temperature of the battery exceeds a limit value, the battery control system controls the heating relay to disconnect the heating main loop.

And a battery management system BMS (battery management system) for controlling the battery to enter or exit the heating mode, wherein the battery management system is connected with a heating relay of the battery heating main loop. The temperature sensor transmits the acquired battery temperature to the battery management system.

Further, the battery management system can receive the temperature of the battery module detected by the temperature sensor, judge the detected temperature and execute preset control logic: when the temperature of the battery is lower than a limit value, the heating relay is closed, the heating main loop is switched on, the heating element works, and heat is transmitted through the heat conducting element to heat the battery module; when the temperature is higher than the limit value, the heating relay is switched off, the heating main loop is switched off, the heating element does not work any more, and the gradual cooling is realized.

Further, the battery management system has the card to die, and main relay has the risk of adhesion to exist, when battery management system or main relay adhesion became invalid, under the unable normal condition of disconnection of battery heating circuit, battery temperature continued rising, if at this moment continued heating, battery module temperature probably continued rising, dangerous situations such as battery explosion or burning take place. At the moment, when the heating element and the heat conducting element reach the set value of the thermal switch, the thermal switch disconnects the battery to heat the main loop, so that the temperature of the circuit is reduced.

Further, when the temperature of the heating element and the heat conducting element drops below the set value of the thermal switch, the thermal switch is automatically closed.

Furthermore, the thermal switch is a normally closed switch, and is preferably arranged at the highest temperature point of the heat conducting element, and the limit value of the thermal switch, namely the open-close temperature, is adjustable.

Furthermore, the heating element is wrapped in the heat conducting element, different heating powers and different spatial trends can be set according to the arrangement and heat dissipation conditions of the battery modules, and the temperature difference of the battery can be reduced; the heating element and the heat conduction element are arranged on the positive pole and the negative pole of the battery module, so that the consistency of the heating temperatures of the two ends of the battery monomer is improved.

Further, the heating element is a heating wire, and the heat conducting element is a bus bar.

Furthermore, a fuse is arranged in the battery heating main loop, and the circuit is disconnected when the heating main loop is short-circuited or overcurrent.

The utility model provides a battery heating protection circuit has following beneficial effect: the battery heating main circuit is connected with the thermosensitive switch in series, so that the battery heating circuit can be effectively disconnected when the battery heating control circuit fails or the relay is adhered, and the function of battery heating protection is achieved. The battery heating protection circuit has the advantages of complete function, simple structure, reliable use and easy control of cost.

Drawings

Fig. 1 is a schematic diagram of a battery heating protection circuit according to an embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of a battery heating protection circuit according to an embodiment 2 of the present invention.

Fig. 3 is a schematic structural diagram of a battery heating protection circuit in a busbar according to an embodiment of the present invention.

Fig. 4 is an assembly structure diagram of the battery heating protection circuit according to the embodiment of the present invention.

The battery pack comprises a battery module 11, a heating relay 12, a thermal switch 21, a heating element 22, a heat conducting element 23, a temperature sensor 14, a battery management system 15, a fuse 13, a main negative relay 16, a heating wire and a connector 24 of a heating loop.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings. The described embodiments are only a part of the present invention, and not all embodiments. All other embodiments obtained by a person skilled in the art based on the present embodiment without any creative effort belong to the protection scope of the present embodiment.

Referring to fig. 1, a battery heating protection circuit includes a battery module 11, a heating relay 12, a thermal switch 21, a heating element 22, a temperature sensor 14, a battery management system 15, a heat conduction element 23, and the like.

Furthermore, the battery heating protection circuit comprises a heating main loop and a control loop for controlling the on-off of the heating main loop.

Further, the battery heating control circuit is composed of a temperature sensor 14, a battery management system 15, a heating relay 12, and the like.

Further, the heating main circuit is formed by connecting the battery module 11, the heating relay 12, the thermal switch 21 and the heating element 22 in series, and the heating element 22 is arranged inside the groove of the heat conducting element 23.

Further, when the temperature sensor 14 detects that the battery temperature reaches the heating-on lower limit temperature, the battery management system 15 controls the heating relay 12 to close, the heating element 22 generates heat, and the heat is transferred to the battery module 11 through the heat conducting element 23.

Further, when the temperature sensor 14 detects that the battery temperature reaches the heating-off lower limit temperature, the battery management system 15 controls the heating relay 12 to be turned off, and the heating element 22 stops heating.

Further, when the temperature sensor 14 fails, or the relay fails, or the battery management system 15 fails, the battery heating circuit cannot be normally disconnected, and the temperature of the heat conducting element 23 continues to rise. When the temperature of the heat conducting element exceeds a certain limit value, the thermosensitive switch 21 is switched off, and the battery stops heating; in a low-temperature environment, when the temperature of the heat-conducting element 23 drops to the closing temperature point of the thermal switch 21, the thermal switch 21 is automatically closed.

Further, the thermo switch 21 can be recovered and continued to be used without maintenance after the heating protection is interrupted.

Further, the heater wires 22 and the bus bars 23 are disposed on both sides of the positive and negative electrodes of the single module, and the number of the heater wires 22 and the bus bars 23 is twice the number of the battery modules.

Referring to the second embodiment, as shown in fig. 2, a fuse 13 is connected in series in the main circuit for heating the battery, and when the current abnormally rises to a certain height and heat, the fuse itself fuses to cut off the current, thereby protecting the circuit from safe operation.

Furthermore, a main negative relay is connected in series in the battery heating main loop. After the charging signal of the whole vehicle is input, the main and negative relays are closed, and the charging mode is started.

Referring to fig. 3, the bus bar 23 is notched, and the heating wire 22 is disposed inside the notch of the bus bar 23; a groove of a thermal switch 21 is arranged in the middle (with the highest temperature) of the busbar 23, and the thermal switch 21 is arranged in the groove; the heating wires are fixedly connected with the bus bar through heat conducting structural adhesive.

Furthermore, the power value of the heating wires 22 can be adjusted according to requirements, the peripheral battery monomer heating wires which dissipate heat quickly are wound more densely, and the heating power is higher; thereby reducing the monomer temperature difference during heating.

Furthermore, the direction of the heating wires on the bus bar 23 can be adjusted according to the requirement (the direction of the grooves of the bus bar), and the temperature difference of the monomers in the heating process can also be reduced.

Referring to fig. 4, a thermal switch 21, a heating wire 22 and a bus bar 23 are disposed on both sides of the battery module, and the outlet end of the heating wire is connected to the high-voltage main circuit through a connector 24.

Claims

1. A battery thermal protection circuit, comprising: the heating device comprises a heating main loop and a control loop for controlling the on-off of the heating main loop;

the heating main loop comprises: the heating device comprises a battery, a heating relay, a heating element, a heat conduction element and a thermosensitive element, wherein the heat conduction element is used for heating the battery and wrapping the heating element, and the thermosensitive element is close to the heat conduction element and is used for disconnecting the heating main loop when the temperature of the heat conduction element exceeds a limit value;

2. The battery heating protection circuit of claim 1, wherein the heat sensitive element closes when the heat conductive element temperature drops below a defined value.

3. The battery heating protection circuit of claim 1, wherein the heat sensitive element is disposed at a point where the heat conductive element has a highest temperature during being heated.

4. The battery heating protection circuit of claim 1, wherein the heating element is a heating wire.

5. The battery heating protection circuit of claim 1, wherein the thermally conductive member is a bus bar.

6. The battery heating protection circuit of claim 1, wherein the heating main circuit is connected in series with a fuse for fusing.