Overheating early warning battery, preparation method therefor, and overheating early warning battery pack

Abstract

The present application relates to an overheating early warning battery, a preparation method therefor, and an overheating early warning battery pack. The overheating early warning battery of the present application comprises a plurality of battery cells, and the surface of each battery cell is provided with a phase change material layer. The material of the phase change material layer comprises a phase change material, and the melting point of the phase change material is 60-80°C. Bubbles are dispersed in the phase change material layer, and the bubbles are filled with a tracer gas. When the temperature of the battery cell rises above the melting point of the phase change material due to overheating, the phase change material is gradually melted, and the tracer gas in the phase change material layer escapes from the interior of the phase change material layer. The tracer gas is monitored to provide an early warning about the overheating of the battery. The overheating early warning battery of the present application can provide a real-time and accurate early warning about the overheating of the battery, and can also provide an early warning about the overheating of a single battery cell to reflect the local overheating of the battery, thereby performing overheating management and control on the battery in the early stage of thermal runaway of the battery.

Description

Overheating warning battery, preparation method thereof and overheating warning battery pack TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical energy storage, in particular to an overheating warning battery, a preparation method thereof and an overheating warning battery pack. BACKGROUND

[0002] Lithium ion battery or sodium ion battery energy storage system can be used as a power source for new power systems, new energy vehicles and electric ships and other high-energy carriers. However, the lithium ion battery or sodium ion battery usually uses an organic electrolyte with a low boiling point and flammability, and the battery material system has a high calorific value. After an abnormal failure occurs in the battery body or the application environment or the electrical equipment, the battery is prone to overheat, which may trigger thermal runaway of the battery. In the energy storage container or battery pack in which the batteries are closely arranged, the thermal runaway is prone to spread and spread, and then evolve into a combustion and explosion event, which seriously threatens the safety of the energy storage system.

[0003] The traditional scheme for overheating warning of the battery mainly involves arranging temperature sensors on the surface of the battery or the bus bar, combining the actual monitoring value of the temperature sensor to warn the thermal runaway, and then taking control measures to realize the safety management of the battery. However, the monitoring of the temperature variable has a lag, and it is difficult to reflect the local overheating state of the battery through single-point temperature monitoring, thereby losing the opportunity to control the overheating of the battery in the early stage of thermal runaway.

[0004] SUMMARY

[0005] The following is a summary of the subject matter described in detail in this document. This summary is not intended to limit the scope of protection of the claims.

[0006] Therefore, it is necessary to provide an overheating warning battery, a preparation method thereof and an overheating warning battery pack. The overheating warning battery in the present application can accurately warn the overheating of the battery in real time, and can also warn the overheating of the single-point battery to reflect the local overheating of the battery, thereby controlling the overheating of the battery in the early stage of thermal runaway.

[0007] In a first aspect, the present application provides an overheating warning battery, comprising a plurality of battery monomers, and a phase change material layer arranged on the surface of each battery monomer.

[0008] The material of the phase change material layer comprises a phase change material, and the melting point of the phase change material is 60-80 DEG C.

[0009] The phase change material layer is internally dispersed with bubbles, and the bubbles are filled with a tracer gas.

[0010] In some embodiments, the phase change material comprises at least one of paraffin, palmitic acid, n-alkane, and stearic acid.

[0011] In some embodiments, the tracer gas comprises at least one of helium, nitrogen, argon, chloroform, and chlorine dioxide.

[0012] In some embodiments, the volume percentage of the bubbles in the phase change material layer is 5% to 10%.

[0013] In some embodiments, the overheating warning battery further comprises a sublimation coating, which is arranged between the phase change material layer and the battery cell.

[0014] The material of the sublimation coating comprises a sublimation material, and the sublimation temperature of the sublimation material is 55°C to 75°C.

[0015] In some embodiments, the sublimation material comprises at least one of iodine and salicylic acid.

[0016] In some embodiments, the overheating warning battery further comprises a cooling material layer, which is arranged on the surface of each battery cell not covered by the phase change material layer.

[0017] The material of the cooling material layer comprises at least one of graphene, lamp black, carbon nanotube, and aluminum oxide.

[0018] In some embodiments, the overheating warning battery further comprises a fire-retardant layer, which is arranged between adjacent battery cells, and the material of the fire-retardant layer comprises a fire-retardant material.

[0019] In some embodiments, the fire-retardant material comprises at least one of aerogel and fireproof cotton.

[0020] In some embodiments, the plurality of battery cells are arranged in an array, and the phase change material layer, the fire-retardant layer, and the phase change material layer are sequentially arranged between adjacent battery cells.

[0021] In a second aspect, the present application provides a preparation method of an overheating warning battery, comprising the following steps:

[0022] Providing a plurality of battery cells;

[0023] Preparing a phase change material layer on the surface of each battery cell, the material of the phase change material layer comprises a phase change material, the melting point of the phase change material is 60°C to 80°C, and the phase change material layer is internally dispersed with bubbles, and the bubbles are filled with a tracer gas.

[0024] In some embodiments, the step of preparing a phase change material layer on the surface of each battery cell comprises the following steps:

[0025] forming a liquid phase change material layer on the surface of the battery cell;

[0026] injecting the tracer gas into the liquid phase change material layer;

[0027] solidifying the liquid phase change material layer.

[0028] In a third aspect, the present application provides a battery pack for overheating warning, which comprises the battery for overheating warning described in any one of the above or the battery for overheating warning prepared by the method for preparing the battery for overheating warning described in any one of the above.

[0029] The battery for overheating warning comprises a plurality of battery cells, and each battery cell is provided with a phase change material layer on the surface thereof. When the battery cell is overheated and the temperature thereof rises above the melting point of the phase change material, the phase change material will gradually melt, and the tracer gas in the phase change material layer will escape from the inside of the phase change material layer. By monitoring the tracer gas through the sensor, the overheating of the battery can be warned. By detecting the content and concentration of the tracer gas, the overheating degree and the overheating speed of the battery can be detected. In the present application, the phase change material layer provided on the surface of the battery cell and the bubbles of the tracer gas dispersed in the phase change material layer can realize real-time and accurate warning of the overheating of the battery. Meanwhile, the phase change material layer is provided on the surface of each battery cell, and the content and concentration of the tracer gas at different positions can be detected to locate the specific battery cell that is overheated, so as to realize the warning of the overheating of the single-point battery. The battery for overheating warning in the present application can realize real-time and accurate warning of the overheating of the battery, and can also realize the warning of the overheating of the single-point battery to reflect the local overheating of the battery, and thus the overheating of the battery can be controlled in the early stage of thermal runaway of the battery.

[0030] Other aspects can become apparent from the following detailed description, when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation to the technical solutions of the present application.

[0032] FIG. 1 is a structural schematic diagram of a battery for overheating warning provided by an embodiment of the present application.

[0033] EXPLANATION OF REFERENCE NUMERALS

[0034] 10, battery cell; 20, phase change material layer; 30, flame-retardant layer. DETAILED DESCRIPTION

[0035] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways from those described herein without departing from the scope of the present application, and it is understood that similar improvements can be made by those skilled in the art in the light of the above teachings. Therefore, the present application is not limited to the following disclosed specific embodiments.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0038] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0039] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] Referring to FIG. 1, an embodiment of the present application provides an overheating early warning battery, which includes a plurality of battery monomers 10, and each battery monomer 10 is provided with a phase change material layer 20 on the surface thereof. The material of the phase change material layer 20 includes a phase change material, and the melting point of the phase change material is 60-80℃. The phase change material layer 20 is internally dispersed with bubbles, and the bubbles are filled with tracer gas.

[0041] The above-mentioned overheating battery early warning battery includes a plurality of battery monomers 10, and each battery monomer 10 is provided with a phase change material layer 20 on the surface thereof. When the battery monomer 10 is overheated to cause the temperature thereof to rise above the melting point of the phase change material, the phase change material will gradually melt, and the tracer gas in the phase change material layer 20 will escape from the inside of the phase change material layer 20. By setting a sensor to monitor the tracer gas, the overheating condition of the battery can be early warned. By detecting the content and concentration of the tracer gas, the overheating degree and the overheating speed of the battery can be detected. In the present application, by setting the phase change material layer 20 on the surface of the battery monomer 10 and the bubbles of the tracer gas dispersed in the phase change material layer 20, the overheating condition of the battery can be accurately early warned in real time. Meanwhile, each battery monomer 10 is provided with the phase change material layer 20 on the surface thereof, so that the content and concentration of the tracer gas of the tracer gas at different positions can be detected to locate the specific battery monomer 10 that is overheated, and the early warning of the single-point battery overheating condition can be realized. In the present application, the overheating early warning battery can accurately early warn the overheating condition of the battery in real time, and can also early warn the single-point battery overheating condition to reflect the local overheating condition of the battery, and thus the overheating control of the battery in the early stage of thermal runaway of the battery can be realized.

[0042] The phase change material has a low melting point, and in the early stage of the overheating of the battery monomer 10, when the temperature of the battery monomer 10 reaches the melting point of the phase change material, the overheating condition of the battery can be monitored, so that the overheating condition of the battery is controlled to prevent the temperature of the battery from further rising. Optionally, the melting point of the phase change material is 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃ or 80℃. Alternatively, the melting point of the phase change material can also be within the range between any two of the above-mentioned melting points.

[0043] It can be understood that the tracer gas is usually a gas used for leak detection of a vacuum system. The tracer gas is easy to be detected or tracked due to its unique mass. The tracer gas has a wide range of applications in many fields, especially in the fields of energy science and technology, civil engineering, etc., and is used in power, ventilation, nuclear industry, etc. The tracer gas usually has the characteristics of chemical inertness, non-reactivity with other substances, low content in air, easy to pass through the leak hole, etc. In this application, the tracer gas is sealed in the phase change material layer 20 in the form of bubbles. When the temperature of the phase change material reaches its melting point due to the temperature rise of the battery cell 10, the phase change material melts and releases the tracer gas sealed in the phase change material layer 20 in the form of bubbles, thereby facilitating the monitoring of the overheating of the battery by detecting the tracer gas.

[0044] In some embodiments, the phase change material includes at least one of paraffin, palmitic acid, n-alkane, and stearic acid.

[0045] In some embodiments, the tracer gas includes at least one of helium, nitrogen, argon, chloroform, and chlorine dioxide.

[0046] In some embodiments, the volume percentage of the bubbles in the phase change material layer 20 is 5% to 10%. Alternatively, 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 can also be within the range between any two of the above-mentioned volume percentages.

[0047] In some embodiments, the overheating warning battery further includes a sublimation coating layer arranged between the phase change material layer 20 and the battery cell 10. The material of the sublimation coating layer includes a sublimation material, and the sublimation temperature of the sublimation material is 55°C to 75°C.

[0048] The sublimation coating layer arranged between the phase change material layer 20 and the battery cell 10 can accelerate sublimation when the temperature of the battery cell rises. 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 absorb part of the heat generated by the overheating of the battery, reduce the temperature of the battery cell, maintain the phase change temperature unchanged, promote the accelerated sublimation of the sublimation coating layer, and play the role of passive cooling and accelerated evaporation of the coating layer.

[0049] In some monomer battery applications, the surface temperature exceeds the allowable temperature of the battery and does not reach the self-heating temperature of the battery material side reaction, and the coating is released by volatilization. During the operation of the energy storage system, if the battery cell is overheated, the sublimation coating reaches the corresponding temperature to accelerate sublimation. By monitoring the content and concentration of gaseous biochemical materials, the overheating degree and speed 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 a range between any two of the above temperatures.

[0050] In some embodiments, the sublimation material includes at least one of iodine and salicylic acid.

[0051] In some embodiments, the overheat warning battery further includes a cooling material layer disposed on the surface of each battery monomer 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.

[0052] The cooling material layer disposed on the surface of each battery monomer 10 not covered by the phase change material layer 20 can direct the heat generated during battery operation, especially the large amount of heat generated during abnormal heat generation when the battery is overheated, to other low-temperature areas in the energy storage system, such as cold plates, ventilation corridors and ventilation exhausts, etc., thereby accelerating heat dissipation and reducing the risk of thermal runaway of the battery monomer 10. At the same time, the cooling material layer in combination with the phase change material layer 20, both of which work together to absorb heat through phase change and radiate heat through the cooling material layer to achieve targeted cooling of the battery in the case of excessive heat generation when the battery cell is abnormal. The material of the above-mentioned cooling material layer has good high-temperature resistance, heat radiation performance and high emissivity, and at the same time, the cooling material layer can form a good thermal reflection section on the surface of the battery monomer 10, which can direct the heat generated during battery operation to other low-temperature areas, reduce heat accumulation and improve the safety of the battery.

[0053] In some embodiments, the overheat warning battery further includes a fire-retardant layer 30 disposed between adjacent battery monomers 10, and the material of the fire-retardant layer 30 includes a fire-retardant material. It can be understood that the fire-retardant layer 30 of the present application can achieve fire-retardant and heat-insulating between adjacent battery monomers 10 by using conventional fire-retardant layers 30 in the art.

[0054] It can be understood that the flame-retardant material is a material that can inhibit or delay combustion without being easily combustible. Conventional flame-retardant materials mainly include bromine, nitrogen, red phosphorus and compounds, antimony trioxide, magnesium hydroxide, aluminum hydroxide and silicon-based flame-retardant materials.

[0055] In some embodiments, the flame-retardant material includes at least one of aerogel and fireproof cotton.

[0056] It can be understood that aerogel refers to a kind of nanoscale porous solid material formed by replacing the liquid phase in the gel with gas through sol-gel method and 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 available environmental temperature range is wide. The outstanding thermal insulation performance of aerogel comes from its porous structure. The pore size of aerogel is smaller than the average free path of air molecules under normal pressure, so the air molecules in the gap are approximately stationary, thereby avoiding the convective heat transfer of air. The extremely low bulk density and tortuous path of the porous structure of aerogel also prevent gaseous and solid heat conduction, and the gap wall can also reduce thermal radiation. The three aspects jointly reduce the heat transfer path, so that aerogel has excellent thermal insulation effect.

[0057] Fireproof cotton, also known as flame-retardant sponge and fireproof sponge, is a polyurethane foaming material with the chemical name of polyurethane foaming material. The main raw materials are fire retardant, isocyanate and polyether, polyol, etc. The auxiliary raw materials are a small amount of freon, water, etc. It is usually synthesized by adding flame retardant to various polyurethane.

[0058] Referring back to FIG. 1, in some embodiments, the plurality of battery monomers 10 are arranged in an array, and the phase change material layer 20, the flame-retardant layer 30 and the phase change material layer 20 are sequentially stacked between adjacent battery monomers 10.

[0059] In some embodiments, the overheat early warning battery includes a plurality of battery monomers 10, and each battery monomer 10 is provided with a phase change material layer 20 on the surface. The phase change material layer 20 is arranged on the two opposite surfaces of the monomer battery. The material of the phase change material layer 20 includes a phase change material with a melting point of 60-80°C. The phase change material layer 20 is internally dispersed with bubbles filled with tracer gas. The phase change material includes at least one of paraffin, palmitic acid, n-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 5-10%. The overheat early warning battery further includes a sublimation coating arranged between the phase change material layer 20 and the battery monomer 10. The material of the sublimation coating includes a sublimation material with a sublimation temperature of 55-75°C. The sublimation material includes at least one of iodine and salicylic acid. The overheat early warning battery further includes a cooling material layer arranged on the surface of each battery monomer 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 nanotube and aluminum oxide. The overheat early warning battery further includes a fire-retardant layer 30 arranged between adjacent battery monomers 10, and the material of the fire-retardant layer 30 includes a fire-retardant material. It can be understood that the fire-retardant layer 30 of the present application can realize the fire-retardant and heat insulation between adjacent battery monomers 10 by the conventional fire-retardant layer 30 in the art. The fire-retardant material includes at least one of aerogel and fireproof cotton. The plurality of battery monomers 10 are arranged in an array, and the phase change material layer 20, the fire-retardant layer 30 and the phase change material layer 20 are sequentially stacked between adjacent battery monomers 10.

[0060] Compared with the conventional battery overheat early warning method, the overheat early warning battery of the present application has the following beneficial effects:

[0061] 1. The conventional method of realizing early warning of battery overheat by arranging temperature sensors in the system in advance has the following problems: due to the cost limitation of the sensors, the number of sensors arranged is limited and cannot capture the temperature state of each battery cell, there is a monitoring blind spot for local thermal runaway, and the temperature monitoring has a lag, and when the abnormal battery cell overheats to a certain extent or even triggers thermal runaway, the alarm is triggered at this time, which is difficult to actively control. By sealing the tracer gas inside the phase change material layer 20 and arranging the sublimation coating on the surface of the battery, when the battery has an overheat risk, the phase change material absorbs heat while releasing the tracer gas, and the sublimation coating accelerates sublimation. By monitoring the content and concentration of the tracer gas and / or gaseous sublimation material, the overheat degree and speed of the battery can be obtained, the early warning of thermal runaway can be realized, and control can be performed.

[0062] 2. Existing energy storage systems lack the ability to control localized thermal runaway and do not consider the cooling requirements of each individual cell. Even after detecting a battery cell showing signs of thermal runaway, they cannot effectively and promptly enhance cooling. This application addresses this by placing a phase change material layer 20 between the flame-retardant layer 30 and the battery cell 10. Through the phase change heat absorption of the phase change material, the overheated battery cell 10 can be cooled in a targeted manner, reducing the risk of thermal runaway. Furthermore, placing the flame-retardant layer 30 between the phase change material layers 20 can prevent the large amount of heat carried by adjacent battery cells 10 due to electrolyte spraying or jet fire when the battery cell 10 temperature becomes too high, thus controlling thermal runaway between adjacent battery cells 10 and minimizing the harm caused by thermal runaway.

[0063] 3. This application provides a cooling material layer on the battery cell 10, which can radiate a large amount of heat generated during battery operation, especially during abnormal heat generation, to low-temperature areas such as cold plates, ventilation corridors, and ventilation exhaust ports. This accelerates heat dissipation, reduces heat accumulation, and further reduces the risk of thermal runaway of the battery cell 10 while ensuring battery performance, thereby improving the safety of the energy storage system.

[0064] Another embodiment of this application provides a method for preparing an overheat warning battery, comprising the following steps:

[0065] Provide multiple battery cells 10;

[0066] A phase change material layer 20 is prepared on the surface of each battery cell 10. The phase change material layer 20 is made of 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 tracer gas is filled inside the bubbles.

[0067] In some embodiments, preparing a phase change material layer 20 on the surface of each battery cell 10 includes the following steps:

[0068] A liquid phase change material layer is formed on the surface of the battery cell 10;

[0069] Inject tracer gas into the interior of the liquid phase change material layer;

[0070] Solidified liquid phase change material layer.

[0071] Another embodiment of this application provides an overheat warning battery pack, including the overheat warning battery of any of the above claims or the overheat warning battery prepared by the preparation method of the overheat warning battery of any of the above claims.

[0072] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application encompasses all such possible combinations.

[0073] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope. It should be pointed out that, for ordinary skilled persons in the art, several modifications 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 should be subject to the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. An overheat warning battery, wherein, The battery cell includes a plurality of battery monomers, and a phase change material layer is arranged on the surface of each battery monomer. The phase change material layer is made of a phase change material with a melting point of 60-80°C. The phase change material layer is internally dispersed with bubbles filled with tracer gas.

2. The overheat warning cell of claim 1, wherein, The phase change material includes at least one of paraffin, palmitic acid, n-alkane and stearic acid.

3. The overheat warning cell of claim 1, wherein, The tracer gas includes at least one of helium, nitrogen, argon, chloroform and chlorine dioxide.

4. The overheat warning cell of claim 1, wherein, The bubbles account for 5-10% of the volume percentage of the phase change material layer.

5. The overheat warning cell of any one of claims 1 to 4, wherein, The superheating warning battery further includes a sublimation coating arranged between the phase change material layer and the battery monomer. Optionally, the sublimation coating is made of a sublimation material with a sublimation temperature of 55-75°C.

6. The overheat warning cell of claim 5, wherein, The sublimation material includes at least one of iodine and salicylic acid.

7. The overheat warning cell of any one of claims 1 to 4, wherein The superheating warning battery further includes a cooling material layer arranged on the surface of each battery monomer not covered by the phase change material layer. Optionally, the cooling material layer is made of at least one of graphene, lamp black, carbon nanotube and aluminum oxide.

8. The overheat warning cell of any one of claims 1 to 4, wherein The superheating warning battery further includes a fire-retardant layer arranged between adjacent battery monomers, and the fire-retardant layer is made of a fire-retardant material.

9. The overheat warning cell of claim 8, wherein, The fire-retardant material includes at least one of aerogel and fireproof cotton.

10. The overheat warning cell of claim 8, wherein, The battery monomers are arranged in an array, and the phase change material layer, the fire-retardant layer and the phase change material layer are sequentially arranged between adjacent battery monomers.

11. A preparation method of a superheating warning battery, including the following steps: Providing a plurality of battery monomers; Preparing a phase change material layer on the surface of each battery monomer, and the phase change material layer is made of a phase change material with a melting point of 60-80°C, and the phase change material layer is internally dispersed with bubbles filled with tracer gas.

12. The method of claim 11, wherein the overheat warning battery is prepared by the steps of: Preparing a phase change material layer on the surface of each battery monomer includes the following steps: Forming a liquid phase change material layer on the surface of the battery monomer; Injecting the tracer gas into the liquid phase change material layer; Solidifying the liquid phase change material layer.

13. A superheating warning battery pack including the superheating warning battery of any one of claims 1-10 or the superheating warning battery prepared by the preparation method of any one of claims 11-12.

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