Overheat warning battery and preparation method thereof, overheat warning battery pack

Abstract

The present application relates to an overheat warning battery and a preparation method thereof, and an overheat warning battery pack. The overheat warning battery of the present application includes a plurality of battery cells, and a phase change material layer is arranged on the surface of each battery cell. The material of the phase change material layer includes a phase change material, and the melting point of the phase change material is 60°C~80°C. Bubbles are dispersed inside the phase change material layer, and the bubbles are filled with tracer gas. When the battery cell is overheated and its temperature rises above the melting point of the phase change material, the phase change material will gradually melt, and cause the tracer gas inside the phase change material layer to escape from the inside of the phase change material layer. Monitoring the tracer gas can warn of the overheating of the battery. The overheat warning battery in the present application can provide real-time and accurate warning of the overheating of the battery. At the same time, it can also realize the warning of the overheating of the battery at a single point to reflect the local overheating of the battery, thereby realizing the overheating control of the battery in the early stage of thermal runaway of the battery.

Description

Technical Field

[0001] The present application relates to the field of electrochemical energy storage technology, and in particular to an overheat warning battery and a preparation method thereof, and an overheat warning battery pack. Background Art

[0002] Lithium-ion battery or sodium-ion battery energy storage systems can serve as a power / energy source for high-energy carriers such as new power systems, new energy vehicles and electric ships. However, lithium-ion batteries or sodium-ion batteries usually use low-boiling-point, flammable organic electrolytes, and the battery material system has a high calorific value. After an abnormal failure occurs in the battery body, application environment, or electrical equipment, it is easy to cause battery overheating, and then trigger battery thermal runaway. In energy storage containers or battery packs where batteries are closely arranged, a chain reaction can easily be triggered, causing thermal runaway to spread and spread, and then evolve into events such as combustion and explosion, which seriously threatens the safety of the energy storage system.

[0003] The traditional solution for overheating warning of batteries is to pre-arrange temperature sensors on the battery surface or busbar, and use the actual monitoring values ​​of the temperature sensors to warn of thermal runaway, and then take control measures to achieve safe battery management. However, the monitoring of temperature variables has a lag, and it is difficult to reflect the local overheating state of the battery through single-point temperature monitoring, which leads to the loss of the opportunity to control the overheating of the battery in the early stage of thermal runaway. Summary of the invention

[0004] Based on this, it is necessary to provide an overheat warning battery and its preparation method, and an overheat warning battery pack. The overheat warning battery in this application can provide real-time and accurate warning of battery overheating. At the same time, it can also provide warning of single-point battery overheating to reflect the local overheating of the battery, thereby achieving overheat control of the battery in the early stage of battery thermal runaway.

[0005] In a first aspect, the present application provides an overheat warning battery, comprising a plurality of battery cells, each of which has a phase change material layer disposed on its surface;

[0006] The material of the phase change material layer includes a phase change material, and the melting point of the phase change material is 60° C. to 80° C.;

[0007] Bubbles are dispersed inside the phase change material layer, and the bubbles are filled with tracer gas.

[0008] In some embodiments, the phase change material includes at least one of paraffin, palmitic acid, normal alkane and stearic acid.

[0009] In some embodiments, the tracer gas includes at least one of helium, nitrogen, argon, chloroform and chlorine dioxide.

[0010] In some embodiments, the bubbles account for 5% to 10% of the volume of the phase change material layer.

[0011] In some embodiments, the overheat warning battery further includes a sublimation coating, and the sublimation coating is disposed between the phase change material layer and the battery cell;

[0012] The material of the sublimation coating includes a sublimation material, and the sublimation temperature of the sublimation material is 55° C. to 75° C.

[0013] In some embodiments, the sublimation material includes at least one of iodine and salicylic acid.

[0014] In some embodiments, the overheat warning battery further includes a cooling material layer, and the cooling material layer is disposed on the surface of each battery cell that is not covered by the phase change material layer;

[0015] The material of the cooling material layer includes at least one of graphene, lamp black, carbon nanotubes and aluminum oxide.

[0016] In some embodiments, the overheat warning battery further includes a flame retardant layer, the flame retardant layer is disposed between adjacent battery cells, and the material of the flame retardant layer includes a flame retardant material.

[0017] In some embodiments, the flame retardant material includes at least one of aerogel and fireproof wool.

[0018] In some embodiments, a plurality of the battery cells are arranged in an array, and the phase change material layer, the flame retardant layer, and the phase change material layer are sequentially stacked between adjacent battery cells.

[0019] In a second aspect, the present application provides a method for preparing an overheat warning battery, comprising the following steps:

[0020] Providing a plurality of battery cells;

[0021] A phase change material layer is prepared on the surface of each battery cell, wherein the material of the phase change material layer includes a phase change material having a melting point of 60° C. to 80° C.; bubbles are dispersed inside the phase change material layer, and the bubbles are filled with a tracer gas.

[0022] In some embodiments, preparing a phase change material layer on the surface of each battery cell comprises the following steps:

[0023] forming a liquid phase change material layer on the surface of the battery cell;

[0024] Injecting the tracer gas into the liquid phase change material layer;

[0025] The liquid phase change material layer is solidified.

[0026] In a third aspect, the present application provides an overheat warning battery pack, comprising the overheat warning battery described in any one of the above items or an overheat warning battery prepared by the preparation method of the overheat warning battery described in any one of the above items.

[0027] The above-mentioned overheated battery warning battery includes a plurality of battery cells, and a phase change material layer is arranged on the surface of each battery cell. When the battery cell is overheated and its temperature rises to above the melting point of the phase change material, the phase change material will gradually melt, and cause the tracer gas inside the phase change material layer to escape from the inside of the phase change material layer. By setting a sensor to monitor the tracer gas, it is possible to warn of the overheating of the battery. By detecting the content and concentration of the tracer gas, the degree of overheating of the battery and the speed of overheating can be detected. The present application can realize real-time and accurate warning of battery overheating by the phase change material layer arranged on the surface of the battery cell and the bubbles of the tracer gas dispersed inside the phase change material layer. At the same time, a phase change material layer is arranged on the surface of each battery cell, and the content and concentration of the tracer gas of the tracer gas at different parts can be detected to locate the specific battery cell that has overheated, so as to realize warning of single-point battery overheating. The overheat warning battery in the present application can provide real-time and accurate warning of battery overheating. At the same time, it can also provide warning of single-point battery overheating to reflect local overheating of the battery, thereby achieving overheating control of the battery in the early stage of battery thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the structure of an overheat warning battery provided in one embodiment of the present application.

[0029] Description of Reference Numerals

[0030] 10. Battery cell; 20. Phase change material layer; 30. Flame retardant layer. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] Reference Figure 1 As shown, an embodiment of the present application provides an overheat warning battery, including a plurality of battery cells 10, and a phase change material layer 20 is provided on the surface of each battery cell 10. The material of the phase change material layer 20 includes a phase change material, and the melting point of the phase change material is 60° C. to 80° C. Bubbles are dispersed inside the phase change material layer 20, and the bubbles are filled with tracer gas.

[0037] The above-mentioned overheated battery warning battery includes a plurality of battery cells 10, and a phase change material layer 20 is arranged on the surface of each battery cell 10. When the battery cell 10 is overheated and its temperature rises to above the melting point of the phase change material, the phase change material will gradually melt, and cause the tracer gas inside the phase change material layer 20 to escape from the inside of the phase change material layer 20. By setting a sensor to monitor the tracer gas, an early warning of the overheating of the battery can be issued. By detecting the content and concentration of the tracer gas, the degree of overheating of the battery and the speed of overheating can be detected. The present application can realize real-time and accurate early warning of battery overheating by the phase change material layer 20 arranged on the surface of the battery cell 10 and the bubbles of the tracer gas dispersed in the phase change material layer 20. At the same time, a phase change material layer 20 is arranged on the surface of each battery cell 10, and the content and concentration of the tracer gas of the tracer gas at different parts can be detected to locate the specific battery cell 10 that has overheated, so as to realize early warning of the overheating of the battery at a single point. The overheat warning battery in the present application can provide real-time and accurate warning of battery overheating. At the same time, it can also provide warning of single-point battery overheating to reflect local overheating of the battery, thereby achieving overheating control of the battery in the early stage of battery thermal runaway.

[0038] The phase change material has a low melting point. In the early stage of overheating of the battery cell 10, when the temperature of the battery cell 10 reaches the melting point of the phase change material, the overheating of the battery can be monitored, so as to control the overheating of the battery to prevent the battery temperature from further increasing. Optionally, the melting point of the phase change material is 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C or 80°C. Alternatively, the melting point of the phase change material can also be within the range between any two of the above melting points.

[0039] It is understandable that tracer gas is usually a gas used to detect leaks in vacuum systems. Tracer gas is easy to detect or track due to its unique quality. Tracer gas has a wide range of applications in many fields, especially in the fields of energy science and technology, civil engineering, and is used in electricity, ventilation, nuclear industry and other scenarios. Tracer gas usually has the characteristics of being chemically inactive, not easy to react with other substances, having a small content in the air, and being easy to pass through leaks. In the present application, the tracer gas is sealed in the form of bubbles inside the phase change material layer 20. When the temperature of the phase change material reaches its melting point due to the increase in the temperature of the battery cell 10, the melting of the phase change material will release the tracer gas sealed in the form of bubbles in the phase change material layer 20, thereby facilitating the monitoring of the overheating of the battery by detecting the tracer gas.

[0040] In some embodiments, the phase change material includes at least one of paraffin, palmitic acid, n-alkane, and stearic acid.

[0041] In some embodiments, the tracer gas includes at least one of helium, nitrogen, argon, chloroform and chlorine dioxide.

[0042] In some embodiments, the volume percentage of the bubbles in the phase change material layer 20 is 5% to 10%. Optionally, the volume percentage of the bubbles in the phase change material layer 20 is 5%, 5.2%, 5.5%, 5.8%, 6%, 6.2%, 6.5%, 6.8%, 7%, 7.2%, 7.5%, 7.8%, 8%, 8.2%, 8.5%, 8.8%, 9%, 9.2%, 9.5%, 9.8% or 10%. Alternatively, the volume percentage of the bubbles in the phase change material layer 20 may also be within the range between any two of the above volume percentages.

[0043] In some embodiments, the overheat warning battery further includes a sublimation coating, which is disposed between the phase change material layer 20 and the battery cell 10. The material of the sublimation coating includes a sublimation material, and the sublimation temperature of the sublimation material is 55°C to 75°C.

[0044] The sublimation coating disposed between the phase change material layer 20 and the battery cell 10 can accelerate sublimation when the temperature of the single battery increases. By detecting the content and concentration of the gaseous sublimation material, the overheating of the battery can also be monitored. At the same time, the melting process of the phase change material can not only absorb part of the heat generated by the overheating of the battery and reduce the temperature of the battery cell, but also maintain the phase change temperature unchanged to promote the accelerated sublimation of the sublimation coating, and at the same time play the role of passive heat dissipation cooling and accelerated volatilization of the coating.

[0045] When the surface temperature of a single cell exceeds the allowable temperature of the battery and does not reach the self-exothermic temperature of the side reaction of the battery material during the application process, the coating volatilizes and releases. During the operation of the energy storage system, if the battery cell is overheated, the sublimation coating reaches the corresponding temperature and accelerates sublimation. By monitoring the content and concentration of gaseous biochemical materials, the degree and speed of overheating of the battery cell can be analyzed to achieve early warning of thermal runaway. Optionally, the sublimation temperature of the sublimation material is 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C or 75°C. Alternatively, the sublimation temperature of the sublimation material can also be within the range between any two of the above temperatures.

[0046] In some of these embodiments, the sublimation material includes at least one of iodine and salicylic acid.

[0047] In some embodiments, the overheat warning battery further includes a cooling material layer, which is disposed on the surface of each battery cell 10 not covered by the phase change material layer 20. The cooling material layer includes at least one of graphene, lamp black, carbon nanotubes and aluminum oxide.

[0048] A cooling material layer is provided on the surface of each battery cell 10 that is not covered by the phase change material layer 20, so that the heat generated during the operation of the battery, especially the large amount of heat generated during the abnormal heat generation when the battery is overheated, can be radiated to other low-temperature areas in the energy storage system, such as cold plates, ventilation corridors, and ventilation exhaust ports, thereby accelerating the dissipation of heat to reduce the risk of thermal runaway of the battery cell 10. At the same time, the cooling material layer is combined with the phase change material layer 20, and the two work together to generate heat during the operation of the system, especially the excessive heat generation under abnormal conditions of the battery cell, through the phase change of the phase change material to absorb heat and the radiation of the cooling material layer to dissipate heat, thereby achieving targeted cooling of the battery. The material of the above-mentioned cooling material layer has good high temperature resistance, thermal radiation performance and high emissivity. At the same time, the cooling material layer can form a good heat reflection cross-section on the surface of the battery cell 10, and can radiate the heat generated during the operation of the battery to other low-temperature areas, reduce heat accumulation, and improve the safety of the battery.

[0049] In some embodiments, the overheat warning battery further includes a flame retardant layer 30, which is disposed between adjacent battery cells 10, and the material of the flame retardant layer 30 includes a flame retardant material. It is understood that the flame retardant layer 30 of the present application can be a conventional flame retardant layer 30 in the art to achieve flame retardant insulation between adjacent battery cells 10.

[0050] It is understood that flame retardant materials are materials that can inhibit or delay combustion but are not easy to burn themselves. Conventional flame retardant materials mainly include bromine-based, nitrogen-based, red phosphorus and compounds, antimony trioxide, magnesium hydroxide, aluminum hydroxide and silicon-based flame retardant materials.

[0051] In some embodiments, the flame retardant material includes at least one of aerogel and fireproof wool.

[0052] It is understood that aerogel refers to a nano-scale porous solid material formed by replacing the liquid phase in the gel with gas through a sol-gel method using a certain drying method. Compared with traditional thermal insulation materials, aerogel has better thermal insulation performance and longer service life. The low thermal conductivity of aerogel ensures its excellent thermal insulation effect, and the usable ambient temperature range is wide. The outstanding thermal insulation performance of aerogel comes from its porous structure. The pore size of aerogel is lower than the mean free path of air molecules at normal pressure, so the air molecules in the gap are approximately stationary, thereby avoiding convective heat transfer of the air. The extremely low volume density of aerogel and the tortuous path of the porous structure also prevent gaseous and solid heat conduction, and the gap wall can also reduce thermal radiation. The three aspects work together to reduce the heat transfer path, giving aerogel an excellent thermal insulation effect.

[0053] Fireproof cotton is also known as flame retardant sponge, fireproof sponge, and flame retardant cotton. Its chemical name is polyurethane foam material. The main raw materials are fire retardants, isocyanates, polyethers, polyols, etc. Auxiliary raw materials include a small amount of freon, water, etc. It is usually synthesized by adding flame retardants to various polyurethanes.

[0054] Refer again Figure 1 As shown, in some embodiments, a plurality of battery cells 10 are arranged in an array, and a phase change material layer 20 , a flame retardant layer 30 and a phase change material layer 20 are sequentially stacked between adjacent battery cells 10 .

[0055] In some embodiments, the overheat warning battery includes a plurality of battery cells 10, and a phase change material layer 20 is disposed on the surface of each battery cell 10. The phase change material layer 20 is disposed on two opposite surfaces of the single battery. The material of the phase change material layer 20 includes a phase change material, and the melting point of the phase change material is 60°C to 80°C. Bubbles are dispersed inside the phase change material layer 20, and the bubbles are filled with tracer gas. The phase change material includes at least one of paraffin, palmitic acid, normal alkane and stearic acid. The tracer gas includes at least one of helium, nitrogen, argon, chloroform and chlorine dioxide. The volume percentage of the bubbles in the phase change material layer 20 is 5% to 10%. The overheat warning battery also includes a sublimation coating, which is disposed between the phase change material layer 20 and the battery cell 10. The material of the sublimation coating includes a sublimation material, and the sublimation temperature of the sublimation material is 55°C to 75°C. The sublimation material includes at least one of iodine and salicylic acid. The overheat warning battery also includes a cooling material layer, which is arranged on the surface of each battery cell 10 not covered by the phase change material layer 20. The material of the cooling material layer includes at least one of graphene, lamp black, carbon nanotubes and aluminum oxide. The overheat warning battery also includes a flame retardant layer 30, which is arranged between adjacent battery cells 10, and the material of the flame retardant layer 30 includes a flame retardant material. It is understandable that the flame retardant layer 30 of the present application can be used through a conventional flame retardant layer 30 in the art to achieve flame retardancy and heat insulation between adjacent battery cells 10. The flame retardant material includes at least one of aerogel and fireproof cotton. A plurality of battery cells 10 are arranged in an array, and a phase change material layer 20, a flame retardant layer 30 and a phase change material layer 20 are sequentially stacked between adjacent battery cells 10.

[0056] Compared with the traditional battery overheat warning method, the overheat warning battery of the present application has the following beneficial effects:

[0057] 1. The traditional method of realizing early warning of battery overheating by pre-arranged temperature sensors in the system is limited by the cost of sensors, the number of arrangements is limited, and the temperature state of each battery cell cannot be captured. There is a monitoring blind spot for local thermal runaway, and there is a lag in temperature monitoring. The alarm is triggered only when the abnormal battery cell overheats to a certain degree or even triggers thermal runaway. At this time, it is difficult to actively control safety. The present application seals the tracer gas inside the phase change material layer 20 and sets a sublimation coating on the surface of the battery. When the battery is at risk of overheating, the phase change material releases the tracer gas while absorbing heat, and the sublimation coating accelerates sublimation. By monitoring the content and concentration of the tracer gas and / or gaseous sublimation material, the degree and speed of battery overheating can be obtained, and early warning of thermal runaway can be achieved, and control can be carried out.

[0058] 2. Existing energy storage systems do not have the ability to control local thermal runaway, and do not consider the cooling requirements of each individual battery cell. Even after a battery cell with a tendency to thermal runaway is found, it is not possible to promptly and effectively strengthen refrigeration in a targeted manner. The present application provides a phase change material layer 20 between the flame retardant layer 30 and the battery cell 10, and absorbs heat through the phase change of the phase change material to perform targeted cooling of the overheated battery cell 10, thereby reducing the risk of thermal runaway. On the other hand, by providing a flame retardant layer 30 between the phase change material layers 20, when the temperature of the battery cell 10 is too high, it can block the huge heat carried by the adjacent battery cells 10 due to the injection of electrolyte, jet fire, etc., control the thermal runaway between adjacent battery cells 10, and control the hazards of thermal runaway to a smaller extent.

[0059] 3. The present application sets a cooling material layer on the battery cell 10, which can radiate a large amount of heat during the operation of the battery, especially during the abnormal heat generation process, to low-temperature areas such as cold plates, ventilation corridors, and ventilation exhaust ports, thereby accelerating heat dissipation and reducing heat accumulation. On the basis of ensuring the performance of the battery, the risk of thermal runaway of the battery cell 10 is further reduced, thereby improving the safety of the energy storage system.

[0060] Another embodiment of the present application provides a method for preparing an overheat warning battery, comprising the following steps:

[0061] Providing a plurality of battery cells 10;

[0062] A phase change material layer 20 is prepared on the surface of each battery cell 10. The material of the phase change material layer 20 includes a phase change material with a melting point of 60°C to 80°C. Bubbles are dispersed inside the phase change material layer 20 and are filled with a tracer gas.

[0063] In some embodiments, preparing the phase change material layer 20 on the surface of each battery cell 10 includes the following steps:

[0064] forming a liquid phase change material layer on the surface of the battery cell 10;

[0065] injecting a tracer gas into the liquid phase change material layer;

[0066] The liquid phase change material layer is solidified.

[0067] Yet another embodiment of the present application provides an overheat warning battery pack, comprising any of the above-mentioned overheat warning batteries or an overheat warning battery prepared by any of the above-mentioned methods for preparing an overheat warning battery.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. An overheat warning battery, It is characterized in that It comprises a plurality of battery cells, each of which has a phase change material layer disposed on its surface; The material of the phase change material layer includes a phase change material, and the melting point of the phase change material is 60° C. to 80° C.; Bubbles are dispersed inside the phase change material layer, and the bubbles are filled with tracer gas; The overheat warning battery further includes a sublimation coating, which is disposed between the phase change material layer and the battery cell; The material of the sublimation coating includes a sublimation material, and the sublimation temperature of the sublimation material is 55° C. to 75° C.; The overheat warning battery further includes a cooling material layer, which is disposed on the surface of each battery cell not covered by the phase change material layer; The material of the cooling material layer includes at least one of graphene, lamp black, carbon nanotubes and aluminum oxide; The overheat warning battery also includes a flame retardant layer, which is arranged between adjacent battery cells, and the material of the flame retardant layer includes a flame retardant material; a plurality of the battery cells are arranged in an array, and the phase change material layer, the flame retardant layer and the phase change material layer are sequentially stacked between adjacent battery cells.

2. The overheat warning battery according to claim 1, It is characterized in that The phase change material includes at least one of paraffin, palmitic acid, normal alkane and stearic acid.

3. The overheat warning battery according to claim 1, It is characterized in that The tracer gas includes at least one of helium, nitrogen, argon, chloroform and chlorine dioxide.

4. The overheat warning battery according to claim 1, It is characterized in that The volume percentage of the bubbles in the phase change material layer is 5% to 10%.

5. The overheat warning battery according to claim 1, It is characterized in that The sublimation material includes at least one of iodine and salicylic acid.

6. The overheat warning battery according to claim 1, It is characterized in that The flame retardant material includes at least one of aerogel and fireproof cotton.

7. An overheat warning battery pack, It is characterized in that The invention comprises the overheat warning battery as claimed in any one of claims 1 to 6.

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