CN215451549U

CN215451549U - Heating film and battery pack

Info

Publication number: CN215451549U
Application number: CN202120417951.4U
Authority: CN
Inventors: 张翔; 鲁志佩; 彭青波; 唐江龙; 郭舒
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2021-02-24
Filing date: 2021-02-24
Publication date: 2022-01-07
Anticipated expiration: 2031-02-24

Abstract

The utility model discloses a heating film and a battery pack. The application sets up heats the membrane, includes the sap bag and is located heating fluid and heating member in the sap bag. The heating membrane that this application set up passes through heating member heating liquid, and then heats the battery module. Because the heating member heats heating liquid earlier, makes the heating film more even to the heating of battery module, and then reduces local dry combustion method, reduces the risk that battery package thermal runaway.

Description

Heating film and battery pack

Technical Field

The utility model relates to the technical field of batteries, in particular to a heating film and a battery pack.

Background

The lithium ion battery is used for the electric automobile, and the performance of the lithium ion battery is obviously influenced by the temperature in all aspects. When the lithium ion battery works under the low-temperature condition, the internal resistance of the battery can be obviously increased, and the capacity is sharply reduced, so that the problems of insufficient power performance, insufficient driving range, limited charging and the like of the whole vehicle at the low temperature are caused.

Therefore, in the related art, the electric vehicle heats the lithium ion battery using the heating film. Generally, a conventional heating film is composed of a heating wire and outer films on both sides. When the heater strip is connected with the power supply, the heater strip generates heat, and then diffuses to the outer membranes on the two sides, thereby heating the battery module. But above-mentioned structure is because only heater strip department heat production, consequently can't accomplish the temperature uniformity to battery module heating to lead to heating film local area effectively to heat, lead to local dry combustion method, have potential thermal runaway risk.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is as follows: to the unable temperature uniformity nature of accomplishing the heating to the battery module of current heating film, and then lead to the problem of local dry combustion method, provide a heating film and battery package.

In order to solve the above technical problem, in a first aspect, the present invention provides a heating film for heating a battery module, including:

the liquid bag contains heating liquid;

the heating element is positioned in the liquid bag and used for heating the heating liquid;

and one end of the connecting piece is electrically connected with the heating piece, and the other end of the connecting piece is used for being matched with power supply equipment.

In an embodiment of the application, the heating element covers substantially the entire sac.

In an embodiment of the present application, the heating member has positive terminal, negative pole end and is located the positive terminal with the common port between the negative pole end, the connecting piece has positive connecting piece and negative pole connecting piece, positive connecting piece with the positive terminal is connected, the negative pole connecting piece with the negative pole end is connected.

In an embodiment of the present application, the positive terminal and the negative terminal of the heating element are located at the same end of the sac, and the common end of the heating element is "S-shaped" and covers substantially the entire sac.

In an embodiment of the application, the connecting piece with one of connecting with the heating member serves and is equipped with temperature sensor, temperature sensor is used for detecting heating fluid temperature, in order to incite somebody to action heating fluid temperature information sends to battery management system.

In a second aspect, the present invention also provides a battery pack, including:

a battery module;

and as described above, the heating film is disposed on the battery module.

In an embodiment of the present application, the battery pack further includes a battery management system, and the battery management system is configured to obtain the battery module temperature and the heating fluid temperature, and control the start and stop of the heating film based on the battery module temperature and the heating fluid temperature.

In an embodiment of the present application, the battery pack further includes a switch, one end of the switch is connected to the connecting member, the other end of the switch is connected to the battery management system, and the switch is further configured to be connected to a power supply device;

the battery management system is also used for controlling the switch to be closed when the battery module temperature is detected to be lower than a first preset temperature so as to start the heating film.

In an embodiment of the application, the battery management system is further configured to control the switch to be turned off to stop the heating film when detecting that the temperature of the heating liquid is greater than a second preset temperature;

wherein the second preset temperature is greater than the first preset temperature.

In an embodiment of the application, the battery management system is further configured to control the switch to be closed to start the heating film to heat when the temperature of the heating liquid is detected to be less than a third preset temperature and the temperature of the battery module is detected to be less than a first preset temperature;

the first preset temperature is lower than the third preset temperature, and the third preset temperature is lower than the second preset temperature.

The beneficial effects of the utility model are as follows: the application sets up heats the membrane, includes the sap bag and is located heating fluid and heating member in the sap bag. The heating membrane that this application set up passes through heating member heating liquid, and then heats the battery module. Because the heating member heats heating liquid earlier, makes the heating film more even to the heating of battery module, and then reduces local dry combustion method, reduces the risk that battery package thermal runaway.

Drawings

Fig. 1 is an exploded view of a battery module according to an embodiment of the present invention.

Fig. 2 is an enlarged partial cross-sectional view taken at a-a' in fig. 1.

Fig. 3 is a schematic structural diagram of a portion of a heating film according to an embodiment of the present invention.

Fig. 4 is a schematic view illustrating a heating control mode of the battery module according to an embodiment of the present invention.

The reference numerals in the specification are as follows:

100. a battery module;

200. a heat-conducting adhesive layer;

300. heating the film; 301. a liquid sac; 3011. an upper bladder body; 3012. a lower bag body; 302. heating the liquid; 303. a heating member; 3031. a positive terminal; 3032. a negative terminal; 3033. a common terminal; 304. a connecting member; 3041. a positive electrode connecting member; 3042. a negative electrode connecting member; 305. a temperature sensor; 306. a seal member;

400. a switch;

500. a battery management system.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the utility model and are not to be construed as limiting the utility model.

In the related art, a conventional heating film is composed of a heating wire and outer films on both sides. When the heater strip is connected with the power supply, the heater strip generates heat, and then diffuses to the outer membranes on the two sides, thereby heating the battery module. However, the above structure only generates heat at the position of the heating wire, so that the temperature uniformity of heating the battery module cannot be achieved. In addition, the faying face of present heating membrane and battery package is connected with heat-conducting glue often commonly used, however if the heat-conducting glue tears the condition and then can't ensure heating membrane and battery package and laminate completely, there is the local region very probably not to laminate with the battery package to lead to heating the unable effective heat conduction in membrane local region, lead to local dry combustion, there is potential thermal runaway risk.

Accordingly, disclosed herein is a heating film 300 and a battery pack. As shown in fig. 2-3, the heating film 300 includes a liquid bladder 301, a heating liquid 302, a heating member 303, and a connecting member 304. The liquid bag 301 is in surface contact with the battery module 100, the liquid bag 301 contains a heating liquid 302 and a heating member 303, the heating member 303 heats the heating liquid 302 to heat the whole heating film 300, and the liquid bag 301 is in surface contact with the battery module 100 to heat the battery module 100 by the heating film 300. The connector 304 has one end connected to the heating member 303 and the other end electrically connected to a power supply device. Further, the power supply device at one end of the connecting member 304 may be the battery module 100 in which the heating film 300 is used for heating, or may be an external battery module 100 or other discharge device. The present application prevents the problem of local dry burning of the heating film 300 by providing the heating film 300 described above.

Specifically, this application is through setting up liquid bag 301 and battery module 100 face contact to hold heating liquid 302 and heating member 303 with it, and then make heating film 300 heat battery module 100 indirectly, heating member 303 heats heating liquid 302 earlier promptly, and heating liquid 302 rethread liquid bag 301 heats battery module 100. Since the heating liquid 302 is filled in the whole liquid sac 301, when the heating member 303 heats the heating liquid 302 in contact with the heating member, the heating liquid 302 flows in the whole liquid sac 301, and the temperature is diffused to the heating liquid 302 in the whole liquid sac 301, so that the temperature of the heating film 300 is at the same level. Compared with the heating film 300 in the related art, the heating film 300 disclosed by the application is more uniform in heating the battery module 100, prevents local dry burning, and reduces the risk of battery thermal runaway.

Further, as shown in fig. 2, the sac 301 disclosed in the present application is divided into an upper sac body 3011 and a lower sac body 3012. Upper balloon body 3011 and lower balloon body 3012 combine to form fluid bladder 301. The liquid sac 301 is generally selected to have a high barrier property and also have a certain thermoplastic property, such as: polytetrafluoroethylene, and the like. The liquid bag 301 is made of an aluminum plastic film, polytetrafluoroethylene and the like, the liquid bag 301 is made of a material with high barrier property, the seepage of the heating liquid 302 can be effectively reduced, and the thermoplastic property is favorable for the liquid bag 301 processing technology and the built-in heating film 300.

Further, as shown in fig. 2-3, the heating element 303 disclosed herein is disposed within the sac 301. Generally, the heating element 303 is generally selected to have a resistance value of a conductive element, such as: copper wire, etc. The heating member 303 is generally required to be capable of generating heat when energized, and thus heating the heating liquid 302.

Further, as shown in fig. 2, a heating liquid 302 is disposed within the sac 301. The heating fluid 302 is generally selected to have a higher boiling point and is not conductive, such as: ethylene glycol, distilled water, and the like.

Still further, the melting point of the material of the liquid bag 301 is higher than the maximum temperature of the heating liquid 302 heated by the heating element 303. The above-mentioned limitation is intended to prevent the temperature of the heating liquid 302 after being heated by the heating member 303 from causing the melting of the liquid bladder 301, thereby causing a problem of leakage of the heating liquid 302. Therefore, in an embodiment of the present application, the liquid bag 301 may be made of an aluminum plastic film, and the heating liquid 302 may be made of distilled water.

In an embodiment of the present application, in order to ensure the uniform heating temperature of the heating film 300 on the battery module 100, the heating element 303 in the heating film 300 should cover substantially the entire liquid bag 301. Specifically, the heating member 303 is provided in an area substantially equal to the area of the liquid bladder 301, which ensures that the heating member 303 generates heat after passing an electric current to the heating liquid 302 in the entire liquid bladder 301. What has been said above generally means that a certain space is generally reserved between the heating member 303 and the liquid sac 301 in order to ensure the size limitation or the requirement of processing precision in the whole liquid sac 301.

In an embodiment of the present application, the connecting member 304 may be a connecting wire harness or a connecting copper bar, and the specific connecting form is not limited.

In one embodiment of the present application, as shown in fig. 3, the heating member 303 has a positive terminal 3031, a negative terminal 3032, and a common terminal 3033 between the positive terminal 3031 and the negative terminal 3032, the connector 304 has a positive connector 3041 and a negative connector 3042, the positive connector 3041 is connected to the positive terminal 3031, and the negative connector 3042 is connected to the negative terminal 3032. The current flows from the positive electrode of the battery module 100 to the negative electrode of the battery module 100 through the positive electrode connector 3041, the positive electrode terminal 3031, the common terminal 3033, the negative electrode terminal 3032 and the negative electrode connector 3042 in sequence.

Further, the positive terminal 3031 and the negative terminal 3032 of the heating member 303 are located at the same end of the sac 301, and the common terminal 3033 of the heating member 303 covers substantially the entire sac 301. The positive terminal 3031 and the negative terminal 3032 of the heating member 303 are located at the same end of the liquid bag 301, so that the connecting member 304 can be effectively utilized, the complexity of connection of the connecting member 304 is avoided, the common terminal 3033 of the heating member 303 covers the whole liquid bag 301, the heating area of the heating member 303 is increased, and the temperature uniformity of the heating film 300 to the battery module 100 is improved.

Still further, as illustrated in FIG. 3, the common end 3033 of the heating member 303 is in an "S" configuration.

In an embodiment of the present application, as shown in fig. 3, a temperature sensor 305 is disposed at one end of the connecting member 304 connected to the heating member 303, and the temperature sensor 305 is configured to detect a temperature of the heating liquid 302. The position where the temperature sensor 305 is disposed is generally selected from the positions where the connector 304 is connected to the heating member 303, and the purpose of this is to enable the temperature information detected by the temperature sensor 305 to be transmitted to the battery management system 500 through the connector 304, thereby improving the utilization rate of the connector 304. Generally, in order to ensure reliability in detecting the temperature of the heating liquid 302, the temperature sensor 305 is provided in plurality and is provided at the positive terminal 3031 and the negative terminal 3032 of the heating member 303, respectively. In the present application, the reason why the temperature sensors 305 are provided only at the positive terminal 3031 and the negative terminal 3032 of the heating member 303 is that: since the heating film 300 of the present application adopts the working mode that the heating member 303 heats the heating liquid 302, and further, compared with the conventional heating film 300, the heating film 300 of the present application heats the temperature more uniformly, the heating film 300 of the present application can detect the temperature of the heating liquid 302 of the entire heating film 300 by only arranging the temperature sensor 305 at the positive terminal 3031 and the negative terminal 3032 of the heating member 303, and the number of the temperature sensors 305 is reduced.

In the present embodiment, as shown in fig. 3, the heating film 300 further includes a sealing member 306. The seal 306 is disposed at the junction of the upper and

lower bodies

3011 and 3012 of the sac 301, and the connector 304 passes through the seal 306 to enter the interior of the sac 301.

In a second aspect, the present application also discloses a battery pack, as shown in fig. 1, which includes a battery module 100, and the above-mentioned heating film 300 disposed on the battery module 100. The heating film 300 transfers the generated heat to the battery module 100 through the thermal conductive adhesive layer 200, thereby achieving heating of the battery module 100 by the heating film 300.

In an embodiment of the present invention, as shown in fig. 1 and 4, the battery pack further includes a thermal conductive adhesive layer 200, the thermal conductive adhesive layer 200 is disposed on the battery module 100, and the heating film 300 is adhered to the battery module 100 through the thermal conductive adhesive layer 200. The arrangement of the thermal conductive adhesive layer 200 can improve the heating efficiency of the heating film 300 to the battery module 100, and improve the stability of the fixing of the heating film 300 on the battery module 100.

Specifically, the heating film 300 has a liquid bladder 301 and a heating liquid 302 due to the present application. Therefore, the heating liquid 302 will only adhere to the thermal conductive adhesive layer 200 due to gravity. Therefore, even if the thermal adhesive layer 200 is broken and is not in contact with the battery module 100, the heating liquid 302 in the heating film 300 is only attached to the surface of the battery module 100 due to gravity, so as to prevent the heating film 300 from being partially dried due to the fact that the heating film 300 cannot be attached to the battery module 100, and further reduce the risk of thermal runaway of the battery.

The battery pack disclosed in the present application further includes a battery management system. The battery management system is used for acquiring the temperature of the battery module and the temperature of the heating liquid, and controlling the starting and stopping of the heating film based on the temperature of the battery module and the temperature of the heating liquid. As shown in fig. 4, the battery management system 500 is connected to the temperature sensor 305 in the heating film 300, and detects the temperature of the heating liquid 302. The battery management system 500 is also connected to a temperature sensor 305 on the battery module 100 for detecting the temperature of the battery module 100.

Further, as shown in fig. 4, the battery pack disclosed in the present application further includes a switch 400, wherein one end of the switch 400 is connected to the connecting member 304, and the other end is electrically connected to the battery management system 500 and the power supply device. When the switch 400 is turned off, the power supply apparatus can supply power to the heating film 300 to satisfy the activation of the heating film 300. In particular, the power supply device may refer to the battery module 100 heated by the heating film 300, or may refer to an external power module or other discharge device. The switch 400 is also connected to the battery management system 500 to be controlled to be closed or opened by the battery management system 500. The battery management system 500 is further configured to control the switch 400 to be closed to start the heating film 300 when detecting that the temperature of the battery module 100 is less than a first preset temperature. The first predetermined temperature is a critical temperature, that is, when the temperature of the battery module 100 reaches the critical temperature, the battery module 100 needs to be heated, so as to prevent the temperature of the battery module 100 from being lower than the critical temperature.

Further, the battery management system 500 is further configured to control the switch 400 to be turned off to stop heating the heating film 300 when detecting that the temperature of the heating liquid 302 is greater than a second preset temperature; wherein the second preset temperature is greater than the first preset temperature. When the battery management system 500 detects that the temperature of the heating fluid 302 is greater than the second preset temperature, the purpose of opening the switch 400 is to ensure that the temperature of the heating fluid 302 is below the long-term operating temperature of the fluid bag 301. The second preset temperature refers to a maximum temperature at which the sac 301 can operate for a long time or stably. And the maximum temperature at which the liquid bladder 301 can operate for a long time or can operate stably is often greater than the first preset temperature. For example, since the liquid bag 301 can operate at 125 ℃ for a long time when it is made of an aluminum plastic film, the second preset temperature is set to 125 ℃ so that the liquid bag 301 can operate stably.

Further, the battery management system 500 is further configured to control the switch 400 to be closed to start the heating film 300 when the temperature of the heating liquid 302 is detected to be less than a third preset temperature and the temperature of the battery module 100 is detected to be less than a first preset temperature; the first preset temperature is lower than the third preset temperature, and the third preset temperature is lower than the second preset temperature. The third predetermined temperature is the lowest temperature at which the heating liquid 302 heats the battery module 100, in other words, the battery module 100 can be effectively heated only when the temperature of the heating liquid 302 is higher than the third predetermined temperature. Therefore, the battery management system 500 needs to determine whether the temperature of the heating fluid 302 is less than the third preset temperature, and if the temperature of the heating fluid 302 is less than the third preset temperature, the switch 400 needs to be closed to start the heating film 300 to heat. Particularly, it is ensured that the temperature of the heating film 300 is changed between the second preset temperature and the third preset temperature, so as to ensure that the power consumption of the heating film 300 is reduced and the service life of the heating film 300 is prolonged while the heating film 300 can effectively heat the battery module 100. In addition, the battery management system 500 determines whether the temperature of the heating liquid 302 is less than the third preset temperature, and also determines whether the temperature of the battery module 100 is less than the first preset temperature. If the battery management system 500 detects that the temperature of the battery module 100 is still less than the first preset temperature after the heating film 300 is turned on, the battery management system 500 also turns on the heating film 300 in real time until the temperature of the battery module 100 is increased to be higher than the first preset temperature.

In other words, during the entire heating process of the battery module, the final purpose thereof is to increase the temperature of the battery module above the first preset temperature. And in order to guarantee the heating efficiency of heating film and improve the life of heating film, consequently require the temperature of heating film to predetermine the temperature and the third and predetermine the temperature change between the temperature, and then can also reduce the consumption of heating film when satisfying battery module and heating effectively, improve the life of heating film. Before the temperature of the battery module reaches the first preset temperature, the switch of the heating film is closed or opened and is controlled according to the temperature of the heating liquid detected by the battery management system, and the battery management system opens the switch until the temperature of the battery module reaches the first preset temperature, stops supplying power to the heating film by the battery module and waits for the next time when the temperature of the battery module is lower than the first preset temperature.

The utility model discloses a battery pack is through setting up battery management system and switch to guarantee that the temperature of battery module is being less than critical temperature (when first preset temperature promptly), can control the heating film effectively and heat the battery module, and battery management system still controls the temperature of heating liquid and changes between maximum operating temperature and minimum operating temperature (between second preset temperature and the third preset temperature promptly) with the switch, with the consumption that reduces the heating film, and improve the life of heating film.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A heating film for heating a battery module, comprising:

the liquid bag contains heating liquid;

2. A heating film as claimed in claim 1, wherein the heating element covers substantially the entire sac.

3. The heating film according to claim 2, wherein the heating element has a positive terminal, a negative terminal, and a common terminal between the positive terminal and the negative terminal, the connecting element has a positive connecting element and a negative connecting element, the positive connecting element is connected to the positive terminal, and the negative connecting element is connected to the negative terminal.

4. A heating film as claimed in claim 3, wherein the positive and negative terminals of the heating element are located at the same end of the sac, and the common terminal of the heating element is "S-shaped" and covers substantially the entire sac.

5. A heating film according to any one of claims 1 to 4, wherein a temperature sensor is arranged at one end of the connecting member connected with the heating element, and the temperature sensor is used for detecting the temperature of the heating liquid so as to send the temperature information of the heating liquid to a battery management system.

6. A battery pack, comprising:

a battery module;

and the heating film according to any one of claims 1 to 5, which is provided on the battery module.

7. The battery pack according to claim 6, further comprising a battery management system configured to obtain the battery module temperature and the heating liquid temperature, and control the heating film to start and stop based on the battery module temperature and the heating liquid temperature.

8. The battery pack of claim 7, further comprising a switch, wherein one end of the switch is connected to the connecting member, and the other end of the switch is connected to the battery management system, and the switch is further configured to be connected to a power supply device;

9. The battery pack according to claim 8, wherein the battery management system is further configured to control the switch to be turned off to stop the heating film when detecting that the temperature of the heating liquid is greater than a second preset temperature;

10. The battery pack according to claim 9, wherein the battery management system is further configured to control the switch to be closed to start heating of the heating film when the temperature of the heating fluid is detected to be less than a third preset temperature and the temperature of the battery module is detected to be less than a first preset temperature;