CN115810828A - A battery heat absorbing coating - Google Patents

Abstract

The present application relates to a battery heat absorbing coating, and provides a method for using the heat absorbing coating to reduce battery temperature. The heat-absorbing coating and method of the present application have a uniform cooling effect on the battery or the battery core, can stably prevent the battery from thermal runaway, and have less impact on the group margin of the battery, and have good application prospects.

Description

A battery heat absorbing coating

technical field

The application relates to a battery heat absorbing coating, which belongs to the technical field of electrochemical batteries.

Background technique

The battery generates heat during charging and discharging, causing the battery temperature to rise. In order to pursue higher energy density, in the process of battery grouping, the distance between batteries is getting smaller and smaller, and a large number of batteries are gathered together to work at the same time. cause damage and, in extreme cases, even thermal runaway.

The purpose of battery thermal management is to ensure that the battery operates within a certain temperature range to prevent damage to the battery or reduce the service life of the battery due to excessive battery temperature. How to cool down the battery and prevent thermal runaway is an urgent technical problem to be solved in battery thermal management.

Contents of the invention

In view of the above technical problems, the present application provides a battery heat absorbing coating, which can effectively cool down the battery and prevent thermal runaway.

In a first aspect, the present application provides a battery, the inner wall of the battery casing or the surface of the battery cell is coated with a coating, the coating has a heat-absorbing material that is not easily oxidized, and the heat-absorbing material is sublimated.

Since the sublimated endothermic material can directly change from solid phase to gas phase and quickly take away heat, when the battery reaches a certain temperature, it can evenly reduce the temperature of the battery by means of the sublimation of the endothermic material in the coating to avoid Thermal runaway; at the same time, because the heat-absorbing material is not easy to oxidize, it can stably exist on the inner wall of the battery shell or the surface of the battery cell, so that the temperature of the battery is in a stable and controllable state for a long time.

In some embodiments, the endothermic materials have different sublimation temperatures.

The heat-absorbing materials with different sublimation temperatures can work in different stages of battery heating, so that the battery temperature can be gradually and continuously reduced.

In some embodiments, the endothermic material includes one or more combinations of terephthalic acid, ferric chloride, benzoic acid, and potassium iodide.

The sublimation temperature of terephthalic acid and ferric chloride is about 300°C, that of benzoic acid is about 100°C, and that of potassium iodide is about 45°C, and they are not easily oxidized. When the surface of the battery cell or the inner wall of the battery case reaches the sublimation temperature of these endothermic materials, the heat-absorbing coating begins to sublimate, directly transforming from a solid state to a gaseous state, and quickly takes away the heat on the surface of the battery cell or the inner wall of the battery case, thereby reducing The temperature rise of the cell or battery.

In some embodiments, the coating has a thickness of 0.3 mm to 2 mm.

Such a thickness can ensure a good cooling effect without significantly occupying the internal space of the battery.

In some embodiments, the thickness of the coating is 0.3 mm to 0.5 mm, 0.5 mm to 1 mm, or 1 mm to 1.5 mm.

This is a more preferable thickness, that is to say, in addition to still ensuring a good cooling effect, it has less impact on the group margin of the battery.

In some embodiments, the coating includes a composite material formed of a heat absorbing material and a carrier.

Compared with pure endothermic materials, the composite material formed by endothermic materials and carriers can be more evenly and stably distributed on the surface of objects, so the cooling effect is also more uniform and stable.

In some embodiments, the carrier includes a combination of one or more of silicone resin, epoxy resin and PE resin.

These resins are well-known carriers, and they have their own advantages. Therefore, they can be used in various situations to form composite materials with various heat-absorbing materials, so as to cool the battery uniformly and stably.

In some embodiments, all sides except the tab end are coated with the coating.

This coating method minimizes battery temperature rise.

In the second aspect, the present application also provides a method for reducing the temperature of the battery cell, which includes coating the inner wall of the battery casing or the surface of the battery cell, the coating has a heat-absorbing material that is not easily oxidized, and the absorber Thermal materials sublimate at a certain temperature.

The principle of this method is that when the battery cell reaches a certain temperature, the heat-absorbing coating on the surface of the battery cell or the inner wall of the battery case begins to sublimate, quickly taking away the heat, and cooling the battery rapidly; at the same time, because the heat-absorbing material is not easy to oxidize, It can stably exist on the inner wall of the battery casing or the surface of the battery cell, so that the temperature of the battery is in a long-term stable and controllable state.

In some embodiments, the endothermic materials have different sublimation temperatures.

The use of endothermic materials with different sublimation temperatures can work in different stages of battery heating, thereby effectively reducing the battery temperature.

In some embodiments, the endothermic material is a combination of one or more of terephthalic acid, ferric chloride, benzoic acid, and potassium iodide.

The sublimation temperature of terephthalic acid and ferric chloride is about 300°C, that of benzoic acid is about 100°C, and that of potassium iodide is about 45°C, and they are not easily oxidized. When the surface of the battery cell or the inner wall of the battery case reaches the sublimation temperature of these endothermic materials, the heat-absorbing coating begins to sublimate, directly transforming from a solid state to a gaseous state, and quickly takes away the heat on the surface of the battery cell or the inner wall of the battery case, thereby reducing The temperature rise of the cell or battery.

In some embodiments, the coating has a thickness of 0.3 mm to 2 mm.

Such a thickness can ensure that the heat-absorbing material has a good cooling effect on the battery through sublimation, and at the same time does not significantly occupy the internal space of the battery.

In some embodiments, 0.3 mm to 0.5 mm, 0.5 mm to 1 mm, or 1 mm to 1.5 mm.

In addition to ensuring a good cooling effect, the optimal thickness has little influence on the group margin of the battery.

In some embodiments, the coating includes a composite material formed of a heat absorbing material and a carrier.

Compared with pure endothermic materials, the composite material formed by endothermic materials and carriers can be more evenly and stably distributed on the surface of objects, so the cooling effect is also more uniform and stable.

In some embodiments, the carrier includes a combination of one or more of silicone resin, epoxy resin and PE resin.

These resins are well-known carriers, and they have their own advantages. Therefore, they can be used in various situations to form composite materials with various heat-absorbing materials, so as to cool the battery uniformly and stably.

In some embodiments, the coating is applied on all sides except the tab end.

This coating method minimizes battery temperature rise.

In a third aspect, the present application further provides a battery module, including the above-mentioned battery.

The battery of the present application can sublimate rapidly at a certain temperature with the help of the heat-absorbing coating on the surface of the battery cell or the inner wall of the battery case; moreover, because the heat-absorbing coating can exist stably, the battery module including the battery is always In a state of stable and controllable temperature.

In a fourth aspect, the present application further provides a battery pack, including the above-mentioned battery module.

The battery of the present application includes a temperature-controllable battery module, so the temperature can always be in a stable and controllable state.

In a fifth aspect, the present application further provides an electrical device, including the above-mentioned battery pack.

The battery pack of the present application maintains a stable temperature due to the heat-absorbing coating in the battery that can sublime but is not easily oxidized, which is conducive to the safe operation of the electric device containing the battery pack and avoids thermal runaway.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the application.

FIG. 1 is a schematic diagram of an exploded structure of a battery cell in some embodiments of the present application.

FIG. 2 is a schematic diagram of a battery module according to an embodiment of the present application.

FIG. 3 is a schematic diagram of a battery pack according to an embodiment of the present application.

FIG. 4 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 3 .

FIG. 5 is a schematic diagram of an electrical device in which a battery is used as a power source according to an embodiment of the present application.

Among them: 1 battery pack; 10 large battery cell; 2 upper box; 20 battery cell; 21 shell; 22 end cap; 3 lower box; 30 positive terminal; 4 battery module; 40 negative terminal; 5 battery; 50 explosion-proof valve.

Detailed ways

Embodiments of the technical solutions of the present application will be described in detail below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and therefore are only examples, rather than limiting the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the application; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to To limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the description of the above drawings are intended to cover a non-exclusive inclusion.

Reference herein to "one or more" means that at least one of the elements is present; there may be a plurality of such elements, unless expressly and specifically defined otherwise.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

In battery thermal management, how to cool down the battery and prevent thermal runaway is a problem that people attach great importance to. Existing solutions include the use of heat sinks/buffer chambers for thermal management, but this method may first have the problem of uneven distribution, for example, it can only cool part of the battery pack or part of the module, which eventually leads to partial Accelerated battery degradation. Secondly, the heat-absorbing material adopts phase-change composite materials or heat-conducting oil, and these materials are prone to oxidation in the natural environment or under high-temperature conditions after the battery heats up.

In order to effectively cool down the battery, the applicant adopts a new battery heat-absorbing material, which can sublimate at a certain temperature, change from solid to gaseous, quickly take away heat, and achieve the effect of cooling the battery.

In order to solve the problem of uneven cooling, the applicant coats the inner wall of the battery casing or the surface of the battery cell, and makes the coating contain a heat-absorbing sublimation material.

In order to avoid oxidation of the endothermic material itself, the applicant uses an endothermic material that is not easily oxidized and has stable properties.

Based on the above considerations, in order to solve the problem of temperature rise of the battery during use, as well as the uneven cooling of the existing cooling means and the easy oxidation of the endothermic material itself, the inventor designed a battery after in-depth research. The inner wall of the casing of the battery or the surface of the cell of the battery is coated with a coating, and the coating has a heat-absorbing material that is not easily oxidized, and the heat-absorbing material sublimates at a certain temperature.

Since the sublimated endothermic material can directly change from solid phase to gas phase and quickly take away heat, when the battery reaches a certain temperature, it can evenly reduce the temperature of the battery by means of the sublimation of the endothermic material in the coating to avoid Thermal runaway; at the same time, because the heat-absorbing material is not easy to oxidize, it can stably exist on the inner wall of the battery shell or the surface of the battery cell, so that the temperature of the battery is in a stable and controllable state for a long time.

The endothermic material disclosed in the embodiments of the present application can be used, but not limited to, for cooling batteries such as lithium batteries, nickel-cadmium batteries, and nickel-metal hydride batteries.

According to some embodiments, the present application provides a battery, the inner wall of the battery case or the surface of the cell of the battery is coated with a coating, the coating has a heat-absorbing material that is not easily oxidized, and the heat-absorbing material has a certain sublimation temperature.

"Coating" is a technique of forming a film layer on the surface of an object, such as dipping, spraying or spin coating.

A "coating" is a continuous film obtained by a single application, which has been specially treated to protect the thin layer of the product.

"Resistant to oxidation" means that the substance is not prone to undergo an oxidation reaction in which electrons are lost.

"Heat absorbing material" means a material that can absorb heat or concentrate heat.

"Sublimation" refers to the phase change process in which a substance changes from a solid state directly to a gaseous state without going through a liquid state. Sublimation is an endothermic process that can be used to cool an object, keeping it cold. Sublimation can be divided into normal pressure sublimation, normal temperature sublimation, vacuum sublimation and low temperature sublimation.

Since the sublimated endothermic material can directly change from solid phase to gas phase and quickly take away heat, when the battery reaches a certain temperature, it can evenly reduce the temperature of the battery by means of the sublimation of the endothermic material in the coating to avoid Thermal runaway; at the same time, because the heat-absorbing material is not easy to oxidize, it can stably exist on the inner wall of the battery shell or the surface of the battery cell, so that the temperature of the battery is in a stable and controllable state for a long time.

In some embodiments, the endothermic materials have different sublimation temperatures.

The heat-absorbing materials with different sublimation temperatures can work in different stages of battery heating, so that the battery temperature can be gradually and continuously reduced.

In some embodiments, the endothermic material includes one or more combinations of terephthalic acid, ferric chloride, benzoic acid, and potassium iodide.

The sublimation temperature of terephthalic acid and ferric chloride is about 300°C, that of benzoic acid is about 100°C, and that of potassium iodide is about 45°C, and they are not easily oxidized. When the surface of the battery cell or the inner wall of the battery case reaches the sublimation temperature of these endothermic materials, the heat-absorbing coating begins to sublimate, directly transforming from a solid state to a gaseous state, and quickly takes away the heat on the surface of the battery cell or the inner wall of the battery case, thereby reducing The temperature rise of the cell or battery.

In some embodiments, the coating has a thickness of 0.3 mm to 2 mm.

Such a thickness can ensure a good cooling effect without significantly occupying the internal space of the battery.

In some embodiments, the thickness of the coating is 0.3 mm to 0.5 mm, 0.5 mm to 1 mm, or 1 mm to 1.5 mm.

This is a more preferable thickness, that is to say, in addition to still ensuring a good cooling effect, it has less impact on the group margin of the battery.

In some embodiments, the coating includes a composite material formed of a heat absorbing material and a carrier.

The "carrier" plays the role of bonding other substances to form a whole. There are many types of carriers, such as polymers (resins) and the like.

"Composite material" is composed of two or more material components with different chemical and physical properties in a designed form, proportion and distribution. Composite materials not only maintain the advantages of the properties of each component material, but also can obtain comprehensive properties that cannot be achieved by a single component material through the complementarity and correlation of the properties of each component.

Compared with pure endothermic materials, the composite material formed by endothermic materials and carriers can be more evenly and stably distributed on the surface of objects, so the cooling effect is also more uniform and stable.

In some embodiments, the carrier includes a combination of one or more of silicone resin, epoxy resin and PE resin.

These resins are well-known carriers, and they have their own advantages. Therefore, they can be used in various situations to form composite materials with various heat-absorbing materials, so as to cool the battery uniformly and stably.

In some embodiments, all sides except the tab end are coated with the coating.

This coating method minimizes battery temperature rise.

According to some embodiments, the present application also provides a method for reducing the temperature of a battery cell, comprising coating a coating on the inner wall of the battery casing or the surface of the battery cell, the coating has a heat-absorbing material that is not easily oxidized, and the The endothermic material sublimates at a certain temperature.

The principle of this method is that when the battery cell reaches a certain temperature, the heat-absorbing coating on the surface of the battery cell or the inner wall of the battery case begins to sublimate, quickly taking away the heat, and rapidly cooling the battery; at the same time, because the heat-absorbing material is not easy to oxidize, It can exist stably on the inner wall of the battery casing or on the surface of the battery cell, so that the temperature of the battery is in a long-term stable and controllable state.

In some embodiments, the endothermic materials have different sublimation temperatures.

The use of endothermic materials with different sublimation temperatures can work in different stages of battery heating, thereby effectively reducing the battery temperature.

In some embodiments, the endothermic material is a combination of one or more of terephthalic acid, ferric chloride, benzoic acid, and potassium iodide.

The sublimation temperature of terephthalic acid and ferric chloride is about 300°C, that of benzoic acid is about 100°C, and that of potassium iodide is about 45°C, and they are not easily oxidized. When the surface of the battery cell or the inner wall of the battery case reaches the sublimation temperature of these endothermic materials, the heat-absorbing coating begins to sublimate, directly transforming from a solid state to a gaseous state, and quickly takes away the heat on the surface of the battery cell or the inner wall of the battery case, thereby reducing The temperature rise of the cell or battery.

In some embodiments, the coating has a thickness of 0.3 mm to 2 mm.

Such a thickness can ensure that the heat-absorbing material has a good cooling effect on the battery through sublimation, and at the same time does not significantly occupy the internal space of the battery.

In some embodiments, 0.3 mm to 0.5 mm, 0.5 mm to 1 mm, or 1 mm to 1.5 mm.

In addition to ensuring a good cooling effect, the optimal thickness has little influence on the group margin of the battery.

In some embodiments, the coating includes a composite material formed of a heat absorbing material and a carrier.

Compared with pure endothermic materials, the composite material formed by endothermic materials and carriers can be more evenly and stably distributed on the surface of objects, so the cooling effect is also more uniform and stable.

In some embodiments, the carrier includes a combination of one or more of silicone resin, epoxy resin and PE resin.

These resins are well-known carriers, and they have their own advantages. Therefore, they can be used in various situations to form composite materials with various heat-absorbing materials, so as to cool the battery uniformly and stably.

In some embodiments, the coating is applied on all sides except the tab end.

This coating method minimizes battery temperature rise.

According to some embodiments, the present application also provides a battery module, including the above-mentioned battery.

The battery of the present application can sublimate rapidly at a certain temperature with the help of the heat-absorbing coating on the surface of the battery cell or the inner wall of the battery case; moreover, because the heat-absorbing coating can exist stably, the battery module including the battery is always In a state of stable and controllable temperature.

According to some embodiments, the present application also provides a battery pack, including the above-mentioned battery module.

The battery of the present application includes a temperature-controllable battery module, so the temperature can always be in a stable and controllable state.

According to some embodiments, the present application also provides an electric device, including the above-mentioned battery pack.

The battery pack of the present application maintains a stable temperature due to the heat-absorbing coating in the battery that can sublime but is not easily oxidized, which is conducive to the safe operation of the electric device containing the battery pack and avoids thermal runaway.

In some embodiments, FIG. 1 serves as an example battery cell. Referring to FIG. 1 , it includes: a battery cell large surface 10 , a battery cell 20 , a casing 21 , an end cap 22 , a positive terminal 30 , a negative terminal 40 , and an explosion-proof valve 50 .

In some embodiments, the batteries can be assembled into a battery module, and the number of batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

FIG. 2 is a battery module 4 as an example. Referring to FIG. 2 , in the battery module 4 , a plurality of batteries 5 may be arranged in sequence along the length direction of the battery module 4 . Of course, it can also be arranged in any other manner. Further, the plurality of batteries 5 can be fixed by fasteners.

Optionally, the battery module 4 may also include a housing with an accommodating space, and a plurality of batteries 5 are accommodated in the accommodating space.

In some embodiments, the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

3 and 4 show the battery pack 1 as an example. Referring to FIGS. 3 and 4 , the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 . Multiple battery modules 4 can be arranged in the battery box in any manner.

In addition, the present application also provides an electric device, the electric device includes at least one of the battery, battery module, or battery pack provided in the present application. The battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device. The electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.

As the electric device, a battery, a battery module or a battery pack can be selected according to its use requirements.

FIG. 5 is an example of an electrical device. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the electric device for the battery, a battery pack or a battery module can be used.

As another example, a device may be a cell phone, tablet, laptop, or the like. The device is usually required to be light and thin, and a battery can be used as a power source.

Example 1

Preparation method: Stir and mix terephthalic acid and N-methylpyrrolidone (NMP) evenly at a weight ratio of 30:1 as an endothermic material; add silicone resin (CAS67763-03-5) as a carrier, endothermic material and The carrier was mixed and stirred according to the mass ratio of 80:20 to make a slurry, and the slurry was coated on the large surface of the battery cell (position 10 in Figure 1) by an ossila slit coater, and then dried at 80°C for 10 minutes. The film is formed by the pressing method of NI-Y1 machine, the pressure is 7000±300kgF, and the time is 70s, the heat-absorbing coating can be formed, and the thickness is 1mm.

Test method: Arrange 3 temperature-sensing wires on the large surface, top cover, and bottom of the battery cell, and pass the thermal abuse test: heat up to 250°C at a rate of 3°C/min in the HE-REJ-72 constant temperature furnace, and set The temperature point is kept at a constant temperature for 2 hours, and the change of the battery cell is monitored.

Embodiment 2, adopt benzoic acid as endothermic material

Preparation method: Stir and mix benzoic acid and N-methylpyrrolidone (NMP) evenly at a weight ratio of 30:1 as the heat-absorbing material; add silicone resin (CAS67763-03-5) as the carrier, and the heat-absorbing material and carrier according to the mass Mix and stir at a ratio of 80:20 to make a slurry, and apply the slurry on the large surface of the battery cell (position 10 in Figure 1) through an ossila slit coater, and then dry it at 80°C for 10 minutes. The film is formed by the pressing method of NI-Y1 machine, the pressure is 7000±300kgF, and the time is 70s, the heat-absorbing coating can be formed, and the thickness is 1mm.

Test method: Arrange 3 temperature-sensing wires on the large surface, top cover, and bottom of the battery cell, and pass the thermal abuse test: heat up to 90°C at a rate of 3°C/min in the HE-REJ-72 constant temperature furnace, and set The temperature point is kept at a constant temperature for 2 hours, and the change of the battery cell is monitored.

Embodiment 3, adopt composite material as endothermic material

Preparation method: Stir and mix terephthalic acid, benzoic acid, potassium iodide, and N-methylpyrrolidone (NMP) at a weight ratio of 30:30:30:1 as an endothermic material; add silicone resin (CAS67763-03-5 ) as a carrier, the endothermic material and the carrier are mixed and stirred according to the mass ratio of 80:20 to make a slurry, and the slurry is coated on the large surface of the battery cell (position 10 in Figure 1) by an ossila slit coater, and then Dry at 80°C for 10 minutes. The film is formed by the pressing method of NI-Y1 machine, the pressure is 7000±300kgF, and the time is 70s, the heat-absorbing coating can be formed, and the thickness is 1.5mm.

Test method: Arrange 3 temperature-sensing wires on the large surface, top cover, and bottom of the battery cell, and pass the heat abuse test: heat up to 50°C, 90°C, 250°C at a rate of 3°C/min in a HE-REJ-72 constant temperature furnace ℃, and maintain a constant temperature for 2 hours at each set temperature point, and monitor the change of the battery cell.

Test results: see Table 1.

Table 1

The heat-absorbing coating of the present application adopts a heat-absorbing material capable of sublimation, which is directly transformed from a solid phase to a gas phase, so that heat can be quickly taken away. When the battery reaches a certain temperature, the temperature of the battery can be uniformly lowered by the sublimation of the endothermic material in the coating to avoid thermal runaway; when the endothermic material with different sublimation temperatures is used, it can work at different stages of battery heating , so that the temperature of the battery is in a stable and controllable state for a long time, effectively avoiding thermal runaway.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit it; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present application. All of them should be covered by the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (19)

1. A battery, characterized in that, the inner wall of the battery casing or the surface of the cell of the battery is coated with a coating, and the coating has a heat-absorbing material that is not easy to oxidize, and the heat-absorbing material is resistant to oxidation at a certain temperature sublimation. 2. The battery according to claim 1, wherein the heat absorbing materials have different sublimation temperatures. 3. The battery according to claim 1 or 2, wherein the heat-absorbing material comprises one or more combinations of terephthalic acid, ferric chloride, benzoic acid and potassium iodide. 4. The battery according to any one of claims 1-3, characterized in that, the thickness of the coating is 0.3mm-2mm. 5 . The battery according to claim 1 , wherein the coating has a thickness of 0.3 mm˜0.5 mm, 0.5 mm˜1 mm, or 1 mm˜1.5 mm. 6. The battery according to any one of claims 1-5, wherein the coating comprises a composite material formed of a heat absorbing material and a carrier. 7. The battery according to claim 6, wherein the carrier comprises a combination of one or more of silicone resin, epoxy resin and PE resin. 8. The battery according to any one of claims 1-7, characterized in that all sides except the tab ends are coated with the coating. 9. A method for reducing the temperature of a battery, characterized in that it includes coating the inner wall of the battery casing or the surface of the battery cell, the coating has a heat-absorbing material that is not easily oxidized, and the heat-absorbing material is placed on the surface of the battery. Sublimation at a certain temperature. 10. The method of claim 9, wherein the heat absorbing materials have different sublimation temperatures. 11. The method according to claim 9 or 10, wherein the endothermic material comprises a combination of one or more of terephthalic acid, ferric chloride, benzoic acid and potassium iodide. 12. The method according to any one of claims 9-11, characterized in that, the coating formed by the coating has a thickness of 0.3mm-2mm. 13. The method according to any one of claims 9-12, characterized in that, the coating formed by the coating has a thickness of 0.3mm-0.5mm, 0.5mm-1mm, or 1mm-1.5mm. 14. The method according to any one of claims 9-13, wherein the coating comprises a composite material formed of a heat absorbing material and a carrier. 15. The method according to claim 14, wherein the carrier comprises one or more combinations of silicone resin, epoxy resin and PE resin. 16. The method according to any one of claims 9-15, characterized in that the coating is performed on all sides except the tab end. 17. A battery module, comprising the battery according to any one of claims 1-8. 18. A battery pack, comprising the battery module according to claim 17. 19. An electrical device, comprising the battery pack according to claim 18.

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