Batteries, their manufacturing methods, and electrical devices

Abstract

This application provides a battery, a method for manufacturing the same, and an electrical device thereof. The battery includes multiple battery cells, with an adhesive layer disposed between at least two of the battery cells. The adhesive layer comprises a thermoplastic elastomer and has a porous structure. This adhesive layer integrates bonding, cushioning, and heat insulation functions. By placing this adhesive layer between at least two battery cells, the safety performance and lifespan of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of secondary battery technology, and in particular to a battery, its preparation method, and an electrical device thereof. Background Technology

[0002] In recent years, the application of secondary batteries, such as lithium-ion batteries, has become increasingly widespread. They are now widely used in energy storage power systems for hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, and electric vehicles. Due to the significant development of secondary batteries, higher requirements have been placed on their energy density, cycle performance, and safety performance. Currently, hot melt adhesives are mostly used as adhesive layers to bond battery cells and form the battery. However, traditional adhesive layers often fail to provide adequate cushioning and thermal insulation, thus affecting battery performance. Summary of the Invention

[0003] To achieve the above objectives, a first aspect of this application provides a battery comprising a plurality of battery cells, wherein an adhesive layer is disposed between at least two of the battery cells, the adhesive layer comprising a thermoplastic elastomer and having a cellular structure.

[0004] The adhesive layer in the battery provided in this application has a porous structure, whose abundant pores effectively reduce heat conduction, thus providing excellent thermal insulation. Simultaneously, this adhesive layer is made of thermoplastic elastomer, which allows it to maintain strong adhesion and high thermal insulation while exhibiting good compression resilience, thereby providing excellent cushioning protection. Therefore, this adhesive layer integrates bonding, cushioning, and thermal insulation functions. Placing this adhesive layer between at least two battery cells can improve the battery's safety performance and lifespan.

[0005] In some embodiments, the pore size of the foam structure is 0.1 mm to 1 mm, and the porosity is 80% to 99%. Therefore, the adhesive layer has high porosity and contains a large number of micron-sized pores, giving it a lightweight and low-density characteristic, thus providing excellent thermal insulation and good cushioning performance.

[0006] In some embodiments, the density of the adhesive layer is ≤0.2 g / cm³. 3 Therefore, the adhesive layer is lightweight and low in density, and its abundant pores can effectively block heat conduction, thus providing excellent thermal insulation performance.

[0007] In some embodiments, the density of the adhesive layer is ≤0.025 g / cm³. 3 As a result, the density of the adhesive layer is further reduced, and the thermal insulation performance is further improved.

[0008] In some embodiments, the thermal conductivity of the adhesive layer is ≤0.05 W / (m·K). Therefore, the adhesive layer has low thermal conductivity and excellent thermal insulation performance.

[0009] In some embodiments, the adhesive layer has a bonding strength of ≥0.65 MPa. Therefore, the high bonding strength of the adhesive layer effectively secures the battery cells and reduces the likelihood of them shifting or detaching.

[0010] In some embodiments, the compression resilience of the adhesive layer is ≥55%. Therefore, the adhesive layer has a high compression resilience and excellent cushioning performance.

[0011] In some embodiments, the compressive modulus of the adhesive layer is ≤0.7MPa. Therefore, the low compressive modulus of the adhesive layer provides good cushioning and protection for the battery cells while maintaining a certain level of support and dimensional stability.

[0012] In some embodiments, the thermoplastic elastomer includes at least one selected from styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, thermoplastic polyurethane elastomers, polyester-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers; the styrene-based thermoplastic elastomer includes at least one selected from styrene-butadiene-styrene triblock copolymers, hydrogenated styrene-butadiene-styrene triblock copolymers, styrene-isoprene-styrene triblock copolymers, and hydrogenated styrene-isoprene-styrene triblock copolymers; the olefin-based thermoplastic elastomer includes at least one selected from ethylene-vinyl acetate copolymers and ethylene-ethyl acrylate copolymers. Thus, the adhesive layer exhibits excellent cushioning and resilience properties and processing and molding performance.

[0013] In some embodiments, the thermoplastic elastomer includes styrene-butadiene-styrene triblock copolymer, styrene-isoprene-styrene triblock copolymer, and thermoplastic polyurethane elastomer. Therefore, by utilizing the synergistic effect of these three thermoplastic elastomers, the adhesive layer exhibits strong adhesion and high compression resilience, serving a dual function of adhesion and cushioning. Furthermore, it facilitates increased porosity, resulting in lower density and lower thermal conductivity, thereby achieving superior thermal insulation performance.

[0014] In some embodiments, the weight ratio of the styrene-butadiene-styrene triblock copolymer, the styrene-isoprene-styrene triblock copolymer, and the thermoplastic polyurethane elastomer is (10~30):(50~70):(10~30). Thus, the three thermoplastic elastomers work synergistically at this weight ratio, resulting in excellent adhesive properties, cushioning properties, and thermal insulation properties in the adhesive layer.

[0015] In some embodiments, the styrene-butadiene-styrene triblock copolymer has a number-average molecular weight of 100,000 to 120,000 and a butadiene weight percentage of 60% to 80%. Thus, the adhesive layer can maintain high adhesion while improving its tensile strength and workability.

[0016] In some embodiments, the styrene-isoprene-styrene triblock copolymer has a number-average molecular weight of 150,000 to 200,000 and an isoprene weight percentage of 70% to 80%. This improves the adhesion between the adhesive layer and the battery cell, and provides good tensile strength and workability.

[0017] In some embodiments, the number-average molecular weight of the thermoplastic polyurethane elastomer is 10,000 to 15,000. This can improve the mechanical strength of the adhesive layer while also aiding in the formation of a low-density, high-porosity adhesive layer.

[0018] In some embodiments, the adhesive layer further includes at least one of a tackifying resin, an inorganic filler, and an antioxidant. Thus, adding a tackifying resin can further improve the adhesive properties of the adhesive layer; adding an inorganic filler can reinforce the adhesive layer and improve its resistance to deformation; and adding an antioxidant can improve the thermo-oxidative stability of the adhesive layer.

[0019] In some embodiments, the tackifying resin includes at least one selected from 145 rosin resin, 138 rosin resin, terpene resin, C5 / C9 copolymer petroleum resin, thermoplastic phenolic resin, and polystyrene resin. Therefore, the above-mentioned tackifying resin has good compatibility or miscibility with the thermoplastic elastomer, which can improve the adhesive performance while also enhancing the elasticity of the adhesive layer.

[0020] In some embodiments, the weight ratio of the thermoplastic elastomer to the tackifying resin is 100:(20~40). Therefore, by controlling the weight ratio of the thermoplastic elastomer to the tackifying resin, the adhesive properties of the adhesive layer can be further improved.

[0021] In some embodiments, the inorganic filler includes at least one selected from calcium carbonate, barium sulfate, and clay. Therefore, the aforementioned inorganic filler provides good reinforcement to the adhesive layer and enhances its resistance to deformation.

[0022] In some embodiments, the inorganic filler has a particle size of 20 nm to 50 nm. Therefore, using inorganic fillers within this particle size range can improve the dispersion uniformity of the inorganic filler in the adhesive layer, enhance the overall reinforcing effect of the adhesive layer, and thus improve the deformation resistance of the adhesive layer.

[0023] In some embodiments, the weight ratio of the thermoplastic elastomer to the inorganic filler is 100:(15~25). This improves the adhesive layer's resistance to deformation.

[0024] In some embodiments, the antioxidant includes at least one selected from 2,6-di-tert-butyl-p-cresol and 4,4′-bis(6-tert-butyl-resorcinol) sulfide. Therefore, the antioxidant can improve the antioxidant properties of the adhesive layer and extend its service life.

[0025] In some embodiments, the weight ratio of the thermoplastic elastomer to the antioxidant is 100:(0.3~0.5). This improves the thermo-oxidative stability of the adhesive layer.

[0026] In some embodiments, the thickness of the adhesive layer is 0.5 mm to 5 mm. Thus, the adhesive layer can provide bonding, cushioning, and thermal insulation while minimizing its thickness, thereby saving internal battery space.

[0027] A second aspect of this application provides a method for preparing a battery, comprising the following steps:

[0028] A hot melt adhesive containing thermoplastic elastomer is melted to obtain a hot melt adhesive liquid;

[0029] The hot melt adhesive liquid is foamed to obtain a foamed adhesive liquid;

[0030] The battery is obtained by bonding at least two battery cells together using the foaming adhesive to form an adhesive layer with a pore structure between the at least two battery cells.

[0031] This application involves melting and foaming a hot melt adhesive to obtain a foamed adhesive solution rich in air bubbles. This foamed adhesive solution is then used to bond battery cells together to form an adhesive layer. This adhesive layer has a porous structure, and its abundant pores effectively reduce heat conduction, thus providing excellent thermal insulation. Simultaneously, the adhesive layer is made of a thermoplastic elastomer, which maintains strong adhesion and high thermal insulation while exhibiting good compression resilience, providing excellent cushioning protection. Therefore, this adhesive layer integrates bonding, cushioning, and thermal insulation functions. Placing this adhesive layer between at least two battery cells can improve battery safety and lifespan. Furthermore, this preparation method is simple, efficient, low-cost, and easily scalable for mass production.

[0032] In some embodiments, the pore diameter of the adhesive layer is 0.1 mm to 1 mm, and the porosity is 80% to 99%. Therefore, the adhesive layer has high porosity and contains a large number of micron-sized pores, giving it a lightweight and low-density characteristic, thus providing excellent thermal insulation and good cushioning performance.

[0033] In some embodiments, the foaming process employs a combined foaming process that combines physical and chemical foaming. This overcomes the problems of uneven cell distribution and easy cell rupture that exist when using physical or chemical foaming alone, resulting in a high foaming ratio in the adhesive layer, thereby forming a low-density cell structure and effectively reducing thermal conductivity and improving cushioning and resilience.

[0034] In some embodiments, the combined foaming process includes the following steps: adding a foaming agent to the hot melt adhesive liquid and introducing compressed gas. Thereby, the foaming agent provides a chemical foaming effect by decomposing to generate gas, while the introduction of compressed gas provides a physical foaming effect. The two work together to effectively increase the foaming ratio of the adhesive layer and reduce its density, thereby achieving excellent thermal insulation and cushioning performance.

[0035] In some embodiments, the mass-to-volume ratio of the thermoplastic elastomer to the compressed gas is 100g:(20L~300L). Therefore, within this range, the mass-to-volume ratio of the thermoplastic elastomer to the compressed gas can significantly increase the foaming ratio of the adhesive layer through sufficient physical foaming, reducing its density and thermal conductivity, thereby improving its thermal insulation and cushioning performance.

[0036] In some embodiments, the mass-to-volume ratio of the thermoplastic elastomer to the compressed gas is 100g:(100L~200L). This further reduces the density and thermal conductivity of the adhesive layer, improves its thermal insulation and cushioning properties, and helps save on the amount of compressed air used.

[0037] In some embodiments, the combined foaming process further includes the following steps: adding a foaming aid and a surfactant to the hot melt adhesive liquid. The foaming aid can increase the gas generation of the foaming agent, adjust the decomposition temperature and rate of the foaming agent, and enhance the foaming effect; the surfactant has a good dispersing effect on the gas generated by chemical foaming and the compressed gas injected by physical foaming, and can promote gas expansion to form a stable cell structure, thereby increasing the foaming ratio of the adhesive layer.

[0038] In some embodiments, the weight ratio of the thermoplastic elastomer, the foaming agent, the foaming aid, and the surfactant is 100:(2~15):(0.02~1):(0.1~1). This increases the foaming ratio of the adhesive layer, reduces its density, creates abundant pores, and improves the thermal insulation and cushioning properties of the adhesive layer.

[0039] In some embodiments, the weight ratio of the thermoplastic elastomer, the foaming agent, the foaming aid, and the surfactant is 100:(5~10):(0.1~0.6):(0.2~0.7). This results in a higher foaming ratio, lower density, and lower thermal conductivity in the adhesive layer, further improving its thermal insulation and cushioning properties, and contributing to cost reduction.

[0040] In some embodiments, the foaming agent includes at least one selected from carbonate foaming agents, bicarbonate foaming agents, sulfonyl hydrazine foaming agents, and azo foaming agents. Therefore, the aforementioned foaming agents have suitable decomposition temperatures and exhibit good dispersibility and high compatibility in thermoplastic elastomers, thereby achieving good foaming effects and providing excellent thermal insulation and cushioning properties.

[0041] In some embodiments, the foaming agent includes at least one of a metal oxide and a metal stearate. Therefore, the aforementioned foaming agent can act as a catalyst to adjust the decomposition temperature and time of the foaming agent, increasing the amount of gas generated and thus improving the foaming ratio to provide superior thermal insulation and cushioning performance.

[0042] In some embodiments, the surfactant includes at least one of sodium dodecyl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate. Therefore, using the above-mentioned surfactant can promote gas dispersion and expansion, making it difficult for the gas formed during foaming to escape from the cells, effectively stabilizing the cell structure and improving foam quality, thereby enhancing thermal insulation and cushioning performance.

[0043] In some embodiments, the compressed gas includes at least one of compressed air, compressed nitrogen, and compressed carbon dioxide. This allows for good physical foaming without reacting with the hot melt adhesive and affecting the performance of the adhesive layer.

[0044] In some embodiments, the melting temperature of the melt treatment is 150°C to 200°C. This allows the hot melt adhesive to be converted into a molten state, facilitating subsequent uniform mixing with foaming agents, foaming aids, and surfactants, and achieving a good foaming effect.

[0045] A third aspect of this application provides an electrical device. The electrical device includes the aforementioned battery, or a battery manufactured using the same method as the aforementioned battery. This improves the safety performance and service life of the electrical device.

[0046] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0047] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0048] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application.

[0049] Figure 2 for Figure 1 An exploded view of a battery cell according to one embodiment of this application is shown.

[0050] Figure 3 This is a schematic diagram of an electrical device that uses a secondary battery as a power source according to one embodiment of this application.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1. Battery cell; 11. Casing; 12. Electrode assembly; 13. Cover plate; 2. Electrical device. Detailed Implementation

[0053] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0054] 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 herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be independently included or excluded, and they can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0056] In this application, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or more" means one or more types.

[0057] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0058] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0059] Those skilled in the art will understand that the order in which the steps are written in the methods of various embodiments or examples does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0060] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0061] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0062] Currently, hot melt adhesive is commonly used as an adhesive layer to bond two adjacent battery cells and form a battery. However, traditional adhesive layers can only achieve the bonding function and are difficult to combine good buffering performance and excellent heat insulation performance, thus failing to provide good protection for battery cells.

[0063] Based on this, one embodiment of this application provides a battery including a plurality of battery cells, with an adhesive layer disposed between at least two battery cells. The adhesive layer includes a thermoplastic elastomer and has a pore structure.

[0064] In this application, unless otherwise specified, "cell battery" refers to the basic unit capable of converting chemical energy into electrical energy. Furthermore, a cell battery typically includes at least a positive electrode, a negative electrode, and an electrolyte. During the charging and discharging process, active ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor for the active ions between the positive and negative electrodes.

[0065] Unless otherwise specified in this application, "battery" can refer to a battery module or a battery pack.

[0066] A battery module includes at least one battery cell. The number of battery cells in a battery module can be one or more, and those skilled in the art can select an appropriate number based on the application and capacity of the battery module.

[0067] In a battery module, multiple battery cells can be arranged sequentially along the length of the module. Of course, they can also be arranged in any other manner. Furthermore, these battery cells can be secured using fasteners.

[0068] Optionally, the battery module may also include a housing with a receiving space in which multiple battery cells are housed.

[0069] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the battery pack may contain one or more battery modules. Those skilled in the art can select an appropriate number based on the application and capacity of the battery pack.

[0070] The battery pack may include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper body and a lower body, with the upper body covering the lower body to form a closed space for accommodating the battery modules. The multiple battery modules can be arranged in any manner within the battery box.

[0071] In this application, thermoplastic elastomer (TPE) is a type of polymer material that has the elasticity of rubber at room temperature and the ability to be plasticized and molded at high temperature, possessing the physical and mechanical properties of vulcanized rubber and the processing properties of thermoplastic plastic.

[0072] In this application, a pore structure refers to a structure with pores (or voids, holes), and the pores in the pore structure can be arranged regularly or irregularly. Pore structures are characterized by being lightweight, low-density, and having a high specific surface area, which can effectively reduce heat conduction.

[0073] The adhesive layer in the battery provided in this application has a porous structure, whose abundant pores effectively reduce heat conduction, thus providing excellent thermal insulation. Simultaneously, this adhesive layer is made of thermoplastic elastomer, which allows it to maintain strong adhesion and high thermal insulation while exhibiting good compression resilience, thereby providing excellent cushioning protection. Therefore, this adhesive layer integrates bonding, cushioning, and thermal insulation functions. Placing this adhesive layer between at least two battery cells can improve the battery's safety performance and lifespan.

[0074] The following is a description of the adhesive layer.

[0075] In some embodiments, the pore size of the foam structure is 0.1 mm to 1 mm, and the porosity is 80% to 99%.

[0076] In this application, pore size has a meaning known in the art and can be tested using instruments and methods known in the art, such as optical microscopy or scanning electron microscopy (SEM). As an example, the pore size of the bubble structure can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or a range of any of the above values. Further, the pore size of the bubble structure can be 0.3 mm to 0.5 mm.

[0077] In this application, porosity refers to the percentage of pore volume in a material to the total volume of the material in its natural state, reflecting the density of the material. High porosity indicates low density. Porosity can be tested using instruments and methods known in the art, and for example, it can be calculated using the following formula: P = (1 - ρ′ / ρ) × 100%, where P represents porosity (in %) and ρ′ represents the bulk density of the material (in g / cm³). 3 ), representing the density of the material (unit: g / cm³). 3 As an example, the porosity of the bubble structure can be 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, or a range of any of the above values. Further, the porosity of the bubble structure can be 90% to 99%.

[0078] As a result, the adhesive layer has high porosity and contains a large number of micron-sized pores, making it lightweight and low-density, thus providing excellent thermal insulation and good cushioning performance.

[0079] In some embodiments, the density of the adhesive layer is ≤0.2 g / cm³. 3 In this application, density has a meaning known in the art and can be tested using instruments and methods known in the art, such as GB / T 6343-2009. As an example, the density of the adhesive layer can be 0.01 g / cm³. 3 0.015g / cm 3 0.02g / cm 3 0.025g / cm 3 0.03g / cm 3 0.035g / cm 3 0.04g / cm 3 0.045g / cm 3 0.05g / cm 3 0.055g / cm 3 0.06g / cm 30.065g / cm 3 0.07g / cm 3 0.075g / cm 3 0.08g / cm 3 0.085g / cm 3 0.09g / cm 3 0.1g / cm 3 0.12g / cm 3 0.14 g / cm 3 0.16g / cm 3 0.18g / cm 3 or 0.2g / cm 3 The value can be any of the above values. Therefore, the adhesive layer is lightweight and low-density, and its abundant pores effectively block heat conduction, providing excellent thermal insulation performance.

[0080] In some embodiments, the density of the adhesive layer is ≤0.025 g / cm³. 3 Furthermore, the density of the adhesive layer can be 0.015 g / cm³. 3 ~0.025g / cm 3 As a result, the density of the adhesive layer is further reduced, and the thermal insulation performance is further improved.

[0081] In some embodiments, the thermal conductivity of the adhesive layer is ≤0.05 W / (m·K). In this application, thermal conductivity has a meaning known in the art and can be tested using instruments and methods known in the art, referring to GB / T 10295-2008, and measured using a heat flow meter. Exemplarily, the thermal conductivity of the adhesive layer can be 0.005 W / (m·K), 0.01 W / (m·K), 0.015 W / (m·K), 0.02 W / (m·K), 0.025 W / (m·K), 0.03 W / (m·K), 0.035 W / (m·K), 0.04 W / (m·K), 0.045 W / (m·K), or 0.05 W / (m·K), or a range of any of the above values. Further, the thermal conductivity of the adhesive layer can be 0.015 W / (m·K) to 0.025 W / (m·K). Therefore, the adhesive layer has a low thermal conductivity and excellent thermal insulation performance.

[0082] In some embodiments, the adhesive layer satisfies the following properties: the adhesive layer includes a first surface and a second surface disposed opposite each other, and the temperature difference between the first surface and the second surface is defined as the heat insulation temperature. When the temperature of the first surface is heated to 200±3°C, the temperature of the second surface is below 140°C. As an example, the temperature of the second surface can be 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, or 140°C, or a range of any of the above values. Further, the temperature of the second surface is below 100°C. Therefore, the adhesive layer has excellent heat insulation performance, providing good heat insulation protection for the battery cells, improving the safety performance and service life of the battery.

[0083] In some embodiments, the adhesive strength of the adhesive layer is ≥0.65 MPa. In this application, adhesive strength has a meaning known in the art and can be tested using instruments and methods known in the art, such as GB / T 7124-2008. As an example, the adhesive strength of the adhesive layer can be 0.65 MPa, 0.7 MPa, 0.75 MPa, 0.8 MPa, 0.85 MPa, 0.9 MPa, 0.95 MPa, 1 MPa, or 1.1 MPa. Further, the adhesive strength of the adhesive layer can be between 0.65 MPa and 0.95 MPa. Therefore, the adhesive strength of the adhesive layer is high, which can effectively fix the battery cells and reduce their displacement and detachment.

[0084] In some embodiments, the compression rebound rate of the adhesive layer is ≥55%. In this application, the compression rebound rate has a well-known meaning in the art and can be tested using instruments and methods known in the art. It can be determined by the following method: Prepare an adhesive layer sample with dimensions of φ10mm × 2mm (diameter 10mm, thickness 2nm). Completely cover the sample surface with the pressure surface of a compression testing machine, compress it to 50% of its rated value, and after decompression, record the rebound thickness. Calculate the compression rebound rate using the formula: Compression rebound rate = (Rebound thickness - Initial thickness × 50%) / (Initial thickness × 50%). Exemplarily, the compression rebound rate of the adhesive layer can be 55%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 75%, 80%, 90%, 100%, or any range of the above values. Further, the compression rebound rate of the adhesive layer can be 65%~75%. Therefore, the adhesive layer has a high compression rebound rate and excellent cushioning performance.

[0085] In some embodiments, the compressive modulus of the adhesive layer is ≤0.7 MPa. In this application, compressive modulus has a well-known meaning in the art and can be tested using instruments and methods known in the art. Referring to GB / T 7757-2009, the compression testing machine should completely cover the sample surface, with a compression rate of 2 mm / min, compressed to 90% strain, and the slope of the linear portion of the compressive stress-strain curve should be extracted as the compressive modulus. The compressive modulus of the adhesive layer can be 0.4 MPa, 0.45 MPa, 0.5 MPa, 0.55 MPa, 0.6 MPa, 0.65 MPa, or 0.7 MPa, or a range of any of the above values. Further, the compressive modulus of the adhesive layer can be 0.55 MPa to 0.65 MPa. Therefore, the low compressive modulus of the adhesive layer can provide good cushioning and protection for the battery cells while maintaining a certain level of support and dimensional stability.

[0086] In some embodiments, the thermoplastic elastomer includes at least one selected from styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, thermoplastic polyurethane elastomers (TPU), polyester-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers. Specifically, styrene-based thermoplastic elastomers include at least one selected from styrene-butadiene-styrene triblock copolymer (SBS), hydrogenated styrene-butadiene-styrene triblock copolymer (SEBS), styrene-isoprene-styrene triblock copolymer (SIS), and hydrogenated styrene-isoprene-styrene triblock copolymer (SEPS). Olefin-based thermoplastic elastomers include at least one selected from ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate copolymer (EEA). In this application, a block copolymer refers to a special copolymer formed by alternating polymerization of two or more polymer segments with different chemical structures. Based on the number of segments constituting the block copolymer, it is classified into diblock copolymers, triblock copolymers, and multiblock copolymers, etc. Therefore, the adhesive layer is made of the aforementioned thermoplastic elastomer, which has excellent cushioning and rebound properties and processing and molding performance.

[0087] In some embodiments, the thermoplastic elastomer includes styrene-butadiene-styrene triblock copolymer (SBS), styrene-isoprene-styrene triblock copolymer (SIS), and thermoplastic polyurethane elastomer (TPU).

[0088] Styrene-butadiene-styrene triblock copolymer (SBS) and styrene-isoprene-styrene triblock copolymer (SIS) are thermoplastic elastomers. They possess advantages such as high tensile strength, excellent elasticity, compression resilience, high adhesion, and good compatibility. Furthermore, they can melt at high temperatures and solidify upon cooling, facilitating the application of adhesive layers. Adding thermoplastic polyurethane elastomer (TPU) can enhance the mechanical strength of the adhesive layer, contributing to higher porosity and thus improving cushioning and insulation properties. Therefore, the synergistic effect of SBS, SIS, and TPU results in strong adhesion and high compression resilience in the adhesive layer, providing both bonding and cushioning. This also helps increase porosity, leading to lower density and lower thermal conductivity, ultimately achieving superior insulation performance.

[0089] In some embodiments, the weight ratio of styrene-butadiene-styrene triblock copolymer (SBS), styrene-isoprene-styrene triblock copolymer (SIS), and thermoplastic polyurethane elastomer (TPU) is (10~30):(50~70):(10~30). The weight ratio of SBS to SIS can be 10:50, 20:50, 30:50, 10:60, 20:60, 30:60, 10:70, 20:70, or 30:70, or any range of the above values; the weight ratio of SBS to TPU can be 10:10, 20:10, 30:10, 10:20, 20:20, 30:20, 10:30, 20:30, or 30:30, or any range of the above values; the weight ratio of SIS to TPU can be 50:10, 50:10, 50:10, 60:20, 60:20, 60:20, 70:30, 70:30, or 70:30, or any range of the above values. Furthermore, the weight ratio of SBS, SIS, and TPU is (15~25):(55~65):(15~25). Thus, SBS, SIS, and TPU work synergistically at this weight ratio, resulting in excellent adhesive properties, cushioning performance, and thermal insulation properties.

[0090] In some embodiments, the number average molecular weight of the styrene-butadiene-styrene triblock copolymer (SBS) is 100,000 to 120,000, for example, 100,000, 105,000, 110,000, 115,000, or 120,000, or any range thereof. In the SBS, the weight percentage of butadiene is 60% to 80%, for example, 60%, 65%, 70%, 75%, or 80%, or any range thereof. Thus, the adhesive layer can improve its tensile strength and workability while maintaining high adhesion.

[0091] In some embodiments, the number average molecular weight of the styrene-isoprene-styrene triblock copolymer (SIS) is 150,000 to 200,000, for example, 150,000, 160,000, 170,000, 180,000, 190,000, or 200,000, or any range thereof. The weight percentage of isoprene is 70% to 80%, for example, 70%, 72%, 74%, 76%, 78%, or 80%, or any range thereof. This improves the adhesion between the adhesive layer and the battery cell, and provides good tensile strength and workability.

[0092] In some embodiments, the number average molecular weight of the thermoplastic polyurethane elastomer (TPU) is 10,000 to 15,000, for example, 10,000, 11,000, 12,000, 13,000, 14,000, or 15,000, or any range of the above values. This can improve the mechanical strength of the adhesive layer while also aiding in the formation of a low-density, high-porosity adhesive layer.

[0093] In some embodiments, the adhesive layer further includes at least one of a tackifying resin, an inorganic filler, and an antioxidant. Thus, adding a tackifying resin can further improve the adhesive properties of the adhesive layer; adding an inorganic filler can reinforce the adhesive layer and improve its resistance to deformation; and adding an antioxidant can improve the thermo-oxidative stability of the adhesive layer.

[0094] In some embodiments, the number average molecular weight of the tackifying resin is 300 to 3000, for example, it can be 300, 500, 800, 1000, 1500, 2000, 2500 or 3000, or any range of the above values. This improves the adhesion of the adhesive layer and enhances its bonding strength with the battery cell.

[0095] In some embodiments, the tackifying resin includes at least one selected from 145 rosin resin, 138 rosin resin, terpene resin, C5 / C9 copolymer petroleum resin, thermoplastic phenolic resin, and polystyrene resin. Therefore, the above-mentioned tackifying resin has good compatibility or miscibility with the thermoplastic elastomer, which can improve the adhesive performance while also enhancing the elasticity of the adhesive layer.

[0096] In some embodiments, the tackifying resin may include at least two of 145 rosin resin, 138 rosin resin, terpene resin, C5 / C9 copolymer petroleum resin, thermoplastic phenolic resin, and polystyrene resin. Therefore, by compounding the tackifying resins, a better tackifying effect can be achieved, improving the overall tackiness of the adhesive layer and facilitating the adjustment of the adhesive layer's heat resistance and flexibility.

[0097] In some embodiments, the weight ratio of thermoplastic elastomer to tackifying resin is 100:(20~40), for example, it can be 100:20, 100:25, 100:30, 100:35 or 100:40, or a range of any of the above values. Therefore, by controlling the weight ratio of thermoplastic elastomer to tackifying resin, the adhesive performance of the adhesive layer can be further improved.

[0098] In some specific embodiments, the tackifying resin may include 145 rosin resin and C5 / C9 copolymer petroleum resin, and the weight ratio of the thermoplastic elastomer, 145 rosin resin, and C5 / C9 copolymer petroleum resin may be 100:(15~30):(5~10). Specifically, the weight ratio of the thermoplastic elastomer to 145 rosin resin may be 100:15, 100:20, 100:25, or 100:30, or a range of any of the above values ​​such as 100:5, 100:6, 100:7, 100:8, 100:9, or 100:10, or any range of the above values. Therefore, the adhesive layer exhibits excellent bonding and cushioning properties.

[0099] In some embodiments, the inorganic filler includes at least one selected from calcium carbonate, barium sulfate, and clay. Clay is a type of soil material derived from aluminosilicate minerals, and may be selected from at least one selected from kaolin, montmorillonite, bentonite, vermiculite clay, illite clay, and chlorite clay. Further, the inorganic filler may include calcium carbonate. Therefore, the above-mentioned inorganic filler has a good reinforcing effect on the adhesive layer and improves the deformation resistance of the adhesive layer.

[0100] In some embodiments, the inorganic filler has a particle size of 20 nm to 50 nm, and its particle size can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm, or any combination of the above values. Therefore, using inorganic fillers within this particle size range can improve the dispersion uniformity of the inorganic filler in the adhesive layer, enhance the overall reinforcing effect of the adhesive layer, and thus improve the deformation resistance of the adhesive layer.

[0101] In some embodiments, the weight ratio of thermoplastic elastomer to inorganic filler is 100:(15~25), for example, it can be 100:15, 100:16, 100:17, 100:18, 100:19, 100:20, 100:21, 100:22, 100:23, 100:24 or 100:25, or a range of any of the above values. This improves the deformation resistance of the adhesive layer.

[0102] In some embodiments, the antioxidant includes at least one selected from 2,6-di-tert-butyl-p-cresol (BHT) and 4,4′-bis(6-tert-butyl-resorcinol) sulfide. Further, the antioxidant may include 2,6-di-tert-butyl-p-cresol (BHT). Thus, the above-mentioned antioxidants can improve the antioxidant properties of the adhesive layer and extend its service life.

[0103] In some embodiments, the weight ratio of thermoplastic elastomer to antioxidant is 100:(0.3~0.5), for example, it can be 100:0.3, 100:0.35, 100:0.4, 100:0.45 or 100:0.5, or any range of the above values. This improves the thermo-oxidative stability of the adhesive layer.

[0104] In some embodiments, the thickness of the adhesive layer is 0.5mm to 5mm, for example, it can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, or any range of the above values. Thus, the adhesive layer can provide bonding, cushioning, and thermal insulation while minimizing its thickness, saving internal space in the battery.

[0105] The following is a description of a single battery cell.

[0106] In this application, the secondary battery includes at least one battery cell. A secondary battery may include one or more battery cells.

[0107] Typically, a battery cell includes a positive electrode, a negative electrode, an electrolyte, and a separator. During charging and discharging, active ions move back and forth between the positive and negative electrodes, inserting and releasing. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0108] The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0109] As a non-limiting example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0110] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be obtained by forming a metal material on a polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymer material substrate in the positive electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0111] In some embodiments, the positive electrode active material may be a known positive electrode active material for batteries. As a non-limiting example, the positive electrode active material may include one or more of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, one or more of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modified compounds. Non-limiting examples of lithium-containing phosphates with an olivine structure include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium manganese iron phosphate and carbon composites. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.8 Co 0.15 Al 0.05 O2.

[0112] In some embodiments, the positive electrode active material layer may optionally include a binder. As a non-limiting example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0113] In some embodiments, the positive electrode active material layer may optionally include a conductive agent. As a non-limiting example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0114] In some embodiments, the positive electrode sheet can be prepared by dispersing the components used to prepare the positive electrode sheet, such as the positive active material, conductive agent, binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry onto at least one surface of the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing, and other processes. The solvent can be selected from, but is not limited to, any of the solvents described in the foregoing embodiments, such as N-methylpyrrolidone (NMP). The surface of the positive electrode current collector coated with the positive electrode slurry can be a single surface or both surfaces of the positive electrode current collector. The solid content of the positive electrode slurry can be 40wt% to 80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s to 25000 mPa·s. When coating the positive electrode slurry, the coating areal density per unit area (dry weight, minus solvent) can be 15 mg / cm³. 2 ~35mg / cm 2 The compaction density of the positive electrode sheet can be 3.0 g / cm³. 3 ~3.6g / cm 3 3.3g / cm³ is an option. 3 ~3.5g / cm 3 .

[0115] The negative electrode sheet includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector, wherein the negative active material layer includes a negative active material.

[0116] As a non-limiting example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0117] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymeric material substrate and a metal layer formed on at least one surface of the polymeric material substrate. The composite current collector can be obtained by forming a metal material on the polymeric material substrate. Non-limiting examples of the metal material in the negative electrode current collector may include one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limiting examples of the polymeric material substrate in the negative electrode current collector may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0118] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0119] In some embodiments, the negative electrode active material layer may optionally include a binder. The binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0120] In some embodiments, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0121] In some embodiments, the negative electrode active material layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0122] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder, and any other components, in a solvent (a non-limiting example of a solvent is deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto at least one surface of a negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing, and other processes. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector. The solid content of the negative electrode slurry can be 40wt%~60wt%. The viscosity of the negative electrode slurry at room temperature can be adjusted to 2000mPa·s~10000mPa·s. When coating the negative electrode slurry, the coating unit areal density (dry weight, deducting solvent) can be 75g / m². 2 ~220g / m 2 The compaction density of the negative electrode sheet can be 1.0 g / cm³. 3 ~ 1.8g / cm 3 .

[0123] Electrolytes function to conduct ions between the positive and negative electrode plates. This application does not impose any particular restrictions on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel, or completely solid.

[0124] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0125] In some embodiments, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorophosphate (LiPO2F2), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0126] In some embodiments, the solvent may include ethylene carbonate (EC, ), propylene carbonate (PC, ), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butene carbonate ( One or more of the following: fluoroethylene carbonate (FEC), methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0127] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0128] In some embodiments, the additives in the electrolyte may include, but are not limited to, one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoromethyl ethylene carbonate (TFPC), etc.

[0129] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0130] In some embodiments, the material of the separator may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0131] In some embodiments, the thickness of the isolation membrane is 6μm to 40μm, and optionally 12μm to 20μm.

[0132] In some embodiments, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding process or a stacking process.

[0133] In some embodiments, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0134] In some embodiments, the outer packaging of the battery cell can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic, and further, non-limiting examples of plastic can include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0135] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1Here is a square-structured battery cell 1 as an example.

[0136] In some of these embodiments, reference is made to Figure 2 The outer packaging of the battery cell 1 may include a housing 11 and a cover plate 13. The housing 11 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the cover plate 13 can be placed over the opening to close the receiving cavity. The positive electrode sheet, negative electrode sheet, and separator can be formed into an electrode assembly 12 by a winding process or a stacking process. The electrode assembly 12 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 12. The number of electrode assemblies 12 contained in the battery cell 1 can be one or more, which can be selected by those skilled in the art according to actual needs.

[0137] Another embodiment of this application provides a method for preparing a battery, comprising the following steps:

[0138] S10: Melt the hot melt adhesive containing thermoplastic elastomer to obtain a hot melt adhesive liquid;

[0139] S20: Foaming treatment is performed on hot melt adhesive liquid to obtain foamed adhesive liquid;

[0140] S30: At least two battery cells are bonded together using a foaming adhesive to form an adhesive layer with a pore structure between the at least two battery cells, thereby obtaining a battery.

[0141] The adhesive layer has a porous structure and a density ≤0.2 g / cm³. 3 .

[0142] This application involves melting and foaming a hot melt adhesive to obtain a foamed adhesive solution rich in air bubbles. This foamed adhesive solution is then used to bond battery cells together to form an adhesive layer. This adhesive layer has a porous structure, and its abundant pores effectively reduce heat conduction, thus providing excellent thermal insulation. Simultaneously, the adhesive layer is made of a thermoplastic elastomer, which maintains strong adhesion and high thermal insulation while exhibiting good compression resilience, providing excellent cushioning protection. Therefore, this adhesive layer integrates bonding, cushioning, and thermal insulation functions. Placing this adhesive layer between at least two battery cells can improve battery safety and lifespan. Furthermore, this preparation method is simple, efficient, low-cost, and easily scalable for mass production.

[0143] In some embodiments, the pore size of the foam structure is 0.1 mm to 1 mm, and the porosity is 80% to 99%. Further, the pore size of the foam structure can be 0.3 mm to 0.5 mm, and the porosity can be 90% to 99%. Thus, the adhesive layer has high porosity and contains a large number of micron-sized pores, giving it a lightweight and low-density characteristic, thereby providing excellent thermal insulation performance and good cushioning performance.

[0144] In some implementations, the foaming process employs a combined foaming process that integrates physical and chemical foaming. This overcomes the problems of uneven cell distribution and easy cell rupture that exist when using physical or chemical foaming alone, resulting in a high foaming ratio of the adhesive layer, thereby forming a low-density cell structure and effectively reducing thermal conductivity and improving cushioning and resilience.

[0145] In some embodiments, the combined foaming process includes the following steps: adding a foaming agent to the hot melt adhesive liquid and introducing compressed gas. Thereby, the foaming agent provides a chemical foaming effect by decomposing to generate gas, while the introduction of compressed gas provides a physical foaming effect. The two work together to effectively increase the foaming ratio of the adhesive layer and reduce its density, thereby achieving excellent thermal insulation and cushioning properties.

[0146] In some embodiments, the mass-to-volume ratio of the thermoplastic elastomer to the compressed gas is 100g:(20L~300L), for example, it can be 100g:20L, 100g:40L, 100g:60L, 100g:80L, 100g:100L, 100g:120L, 100g:140L, 100g:160L, 100g:180L, 100g:200L, 100g:220L, 100g:240L, 100g:260L, 100g:280L, or 100g:300L, or any range of the above values. Therefore, within this range, the mass-to-volume ratio of the thermoplastic elastomer to the compressed gas can significantly increase the foaming ratio of the adhesive layer through sufficient physical foaming, reducing its density and thermal conductivity, thereby improving its thermal insulation and cushioning performance.

[0147] In some embodiments, the mass-to-volume ratio of thermoplastic elastomer to compressed gas can be 100g:(100L~200L). This further reduces the density and thermal conductivity of the adhesive layer, improves its thermal insulation and cushioning properties, and helps save on compressed air consumption.

[0148] In some embodiments, the compressed gas includes at least one of compressed air, compressed nitrogen, and compressed carbon dioxide. Further, the compressed gas may include compressed air. This allows for good physical foaming without reacting with the hot melt adhesive and affecting the performance of the adhesive layer.

[0149] In some embodiments, the compression ratio of the compressed gas is 6 to 10 times, for example, 6, 7, 8, 9, or 10 times, or any range of the above values. This increases the total amount of gas introduced into the hot melt adhesive, thereby increasing the foaming ratio of the adhesive layer.

[0150] In some embodiments, the combined foaming process further includes the following steps: adding a foaming aid and a surfactant to the hot melt adhesive liquid. The foaming aid can increase the gas generation of the foaming agent, adjust the decomposition temperature and rate of the foaming agent, and enhance the foaming effect; the surfactant has a good dispersing effect on the gas generated by chemical foaming and the compressed gas injected by physical foaming, and can promote gas expansion to form a stable cell structure, thereby increasing the foaming ratio of the adhesive layer.

[0151] In some embodiments, the weight ratio of the thermoplastic elastomer, foaming agent, foaming aid, and surfactant is 100:(2~15):(0.02~1):(0.1~1). The weight ratio of the thermoplastic elastomer to the foaming agent can be 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, or 100:15, or a range of any of the above values; the weight ratio of the thermoplastic elastomer to the foaming aid can include 100:0.02, 100:0.05, 100:0.08, 100:0.1, 100:0.2, 10... The weight ratio of thermoplastic elastomer to surfactant can be 0:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, or 100:1, or any range of the above values; the weight ratio of thermoplastic elastomer to surfactant can be 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, or 100:1, or any range of the above values. This allows for an increase in the foaming ratio of the adhesive layer, a decrease in its density, the formation of abundant pores, and an improvement in the thermal insulation and cushioning properties of the adhesive layer.

[0152] In some embodiments, the weight ratio of thermoplastic elastomer, foaming agent, foaming aid, and surfactant is 100:(5~10):(0.1~0.6):(0.2~0.7). This results in an adhesive layer exhibiting a higher foaming ratio, lower density, and lower thermal conductivity, further improving thermal insulation and cushioning performance, and contributing to cost reduction.

[0153] In some embodiments, the blowing agent includes at least one selected from carbonate blowing agents, bicarbonate blowing agents, sulfonyl hydrazine blowing agents, and azo blowing agents. Specifically, the bicarbonate blowing agent may be selected from at least one selected from sodium bicarbonate (NaHCO3), ammonium bicarbonate (NH4HCO3), and calcium bicarbonate (Ca(HCO3)2); the carbonate blowing agent may be selected from at least one selected from sodium carbonate (Na2CO3), ammonium carbonate ((NH4)2CO3), and calcium carbonate (CaCO3); the sulfonyl hydrazine blowing agent may be selected from at least one selected from benzenesulfonyl hydrazine (BSH), p-toluenesulfonyl hydrazine (TSH), and 2,4-toluenedisulfonyl hydrazine; and the azo blowing agent may be selected from at least one selected from azodicarbonamide (AC), azobisisobutyronitrile (AIBN), barium azodicarbonate, barium azodicarboxylate, and potassium azoformamide formate. Further, the blowing agent may include NaHCO3. Therefore, the above-mentioned foaming agent has a suitable decomposition temperature and good dispersibility and high compatibility in thermoplastic elastomers, thereby achieving a good foaming effect and providing excellent thermal insulation and cushioning performance.

[0154] In some embodiments, the foaming aid includes at least one of a metal oxide and a metal stearate. The metal oxide may be selected from at least one of zinc oxide (ZnO), lead oxide (PbO), cadmium oxide (CdO), and manganese oxide (MnO); the metal stearate may be selected from at least one of zinc stearate, chromium stearate, barium stearate, and calcium stearate. Further, the foaming aid may include zinc oxide (ZnO). Therefore, the above-mentioned foaming aid can act as a catalyst to adjust the decomposition temperature and decomposition time of the foaming agent, increase the gas evolution, and thereby improve the foaming ratio to provide superior thermal insulation and cushioning performance.

[0155] In some embodiments, the surfactant includes at least one of sodium dodecyl sulfate (SDS) and sodium fatty alcohol polyoxyethylene ether sulfate (AES). Further, the surfactant may include sodium dodecyl sulfate (SDS). Thus, by using the above-mentioned surfactant, the dispersion and expansion of the gas can be promoted, making it difficult for the gas formed during foaming to escape from the cells, effectively stabilizing the cell structure and improving the foam quality, thereby enhancing the thermal insulation and cushioning performance.

[0156] In some embodiments, the foaming process is carried out under stirring conditions at a speed of 500 rpm to 1000 rpm. The stirring speed can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, or 1000 rpm, or any combination of the above values. This allows the foaming agent, foaming aid, surfactant, and compressed air to be uniformly dispersed in the hot melt adhesive, improving the uniformity and stability of the cell distribution, thereby increasing the foaming ratio.

[0157] In some embodiments, the melting temperature of the melt treatment is 150°C to 200°C, for example, it can be 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C, or any range of the above values. Further, the melting temperature of the melt treatment can be 160°C to 180°C. Thus, the hot melt adhesive can be transformed into a molten state, facilitating subsequent uniform mixing with the foaming agent, foaming aid, and surfactant, and achieving a good foaming effect.

[0158] In some embodiments, the method for preparing hot melt adhesive includes the following steps:

[0159] S11: A thermoplastic elastomer is obtained by mixing styrene-butadiene-styrene triblock copolymer (SBS), styrene-isoprene-styrene triblock copolymer (SIS), and thermoplastic polyurethane elastomer (TPU).

[0160] S12: Mix thermoplastic elastomer, tackifying resin and antioxidant to obtain the first mixture;

[0161] S13: Mix the first mixture and the inorganic filler to obtain the second mixture;

[0162] S14: The second mixture is subjected to intensive mixing to obtain hot melt adhesive.

[0163] Thus, the thermoplastic elastomer, tackifying resin, antioxidant, and inorganic filler can be uniformly dispersed, and the entire system reacts fully during the mixing process to obtain a hot melt adhesive with high elasticity, high strength, and thermoplasticity. Steps S11, S12, and S13 can employ methods and equipment known in the art to mix the components uniformly. There are no particular limitations on the mixing time, and the mixing speed can be 20 rpm to 100 rpm, for example, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, or 100 rpm. Further, SBS, SIS, and TPU are stirred uniformly at 20 rpm to 50 rpm, and the thermoplastic elastomer, tackifying resin, and antioxidant are stirred at 80 rpm to 100 rpm for 30 to 60 minutes.

[0164] In some embodiments, the mixing temperature for the internal mixing process is 150°C to 180°C, and the mixing time is 5 min to 7 min. The mixing temperature can be 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, or 180°C, or any range of these values; the mixing time can be 5 min, 5.5 min, 6 min, 6.5 min, or 7 min. Thus, the components in the second mixture can fully react to form a highly elastic, high-strength, thermoplastic hot melt adhesive.

[0165] In some embodiments, after the internal mixing process, the following step is also included: passing the hot melt adhesive through a two-roll mill 10 to 15 times while it is still hot to improve the uniformity and smoothness of the hot melt adhesive.

[0166] In some embodiments, a foaming adhesive is used to bond at least two battery cells to form an adhesive layer between the at least two battery cells. This includes the following steps: applying a foaming adhesive to the surface of a battery cell to form a liquid film, attaching another battery cell to the liquid film, and cooling the liquid film to solidify it into an adhesive layer, thereby obtaining a battery.

[0167] In some implementations, the opposing surfaces of adjacent battery cells are large surfaces, and the adhesive layer is placed between the two opposing large surfaces to achieve better adhesion, cushioning, and heat insulation.

[0168] Another embodiment of this application provides an electrical device. This electrical device includes the aforementioned battery, or a battery manufactured using the same method as described above. This improves the safety performance and lifespan of the electrical device.

[0169] Understandably, the aforementioned battery can be a power source for an electrical device or an energy storage unit for that device. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc., but are not limited to these.

[0170] As an electrical device, the aforementioned batteries can be selected according to its usage requirements.

[0171] Figure 3 Here is an example of an electrical device 2. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device, a battery pack or battery module can be used.

[0172] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source, but are not limited to this; they can also use a battery pack or battery module.

[0173] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0174] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0175] Example 1

[0176] 1) Preparation of hot melt adhesive:

[0177] Take 20 parts by weight of styrene-butadiene-styrene triblock copolymer (SBS), 60 parts by weight of styrene-isoprene-styrene triblock copolymer (SIS), and 20 parts by weight of thermoplastic polyurethane elastomer (TPU), and stir them thoroughly at a speed of 50 rpm to obtain thermoplastic elastomer.

[0178] Add 21 parts by weight of 145 rosin resin, 7 parts by weight of C5 / C9 copolymer petroleum resin, and 0.3 parts by weight of antioxidant 2,6-di-tert-butyl-p-cresol (BHT) to the thermoplastic elastomer, increase the speed to 100 rpm and continue stirring for 60 min to obtain the first mixture.

[0179] The first mixture is added to an internal mixer, and 20 parts by weight of ultrafine calcium carbonate with an average particle size of 35±10nm are added. The mixture is mixed for 5 minutes to ensure that the ultrafine calcium carbonate is evenly dispersed, thus obtaining the second mixture.

[0180] Raise the temperature of the internal mixer to 162±3℃ and heat and mix for 5 minutes to allow the system to react fully. After the reaction is complete, while still hot, pass the mixture through a rolling mill 10 times to obtain a hot melt adhesive with high elasticity, high strength, and thermoplasticity.

[0181] 2) Battery fabrication:

[0182] The hot melt adhesive is heated to 170±10℃ to obtain a molten hot melt adhesive liquid.

[0183] 0.5 parts by weight of sodium dodecyl sulfate (SDS) were prepared into a 10% SDS solution. 8 parts by weight of sodium bicarbonate (NaHCO3), 0.1 parts by weight of zinc oxide (ZnO), and the SDS solution were added to the hot melt adhesive liquid. The compressed air was injected at a flow rate of 10 L / s according to a mass-volume ratio of thermoplastic elastomer to compressed air of 100 g: 10 L, and stirred thoroughly at a speed of 1000 rpm to foam the adhesive liquid, thus obtaining a foamed adhesive liquid.

[0184] Molten foamed adhesive is coated onto the surface of a single battery cell to form a liquid film. Another battery cell is then attached to the liquid film. The liquid film is then cooled to solidify, forming an adhesive layer with a porous structure, thus obtaining the battery.

[0185] As shown in Table 1 below, the preparation methods of the batteries in Examples 2-26 and Comparative Examples 1-8 are similar to those of the battery in Example 1, with the specific differences from Example 1 as follows:

[0186] Examples 2-6: The amount of compressed air used is different;

[0187] Examples 7-10: Different amounts of foaming agent were used;

[0188] Examples 11-15: Different amounts of foaming agent were used;

[0189] Examples 16-19: Different amounts of surfactant were used;

[0190] Examples 20-26: The weight ratios of SBS, SIS, and TPU are different;

[0191] Comparative Example 1: No foaming treatment was performed.

[0192] Table 1. Relevant parameters of the adhesive layer

[0193]

[0194] Test case

[0195] The adhesive layers in the batteries of Examples 1-26 and Comparative Examples 1-8 were tested as follows:

[0196] (1) Bond strength: Refer to GB / T 7124-2008, the size of the bonding area is 25mm×12.5mm, and the thickness of the test sample is 2mm.

[0197] (2) Compression rebound rate: The adhesive layer is made into a sample with a sample size of φ10mm×2mm. The pressure surface of the compression tester is completely covered to the sample surface. The sample is compressed at 50% compression. After decompression, the rebound thickness is recorded and the compression rebound rate is calculated. The calculation formula is: Compression rebound rate = (rebound thickness - initial thickness × 50%) / (initial thickness × 50%).

[0198] (3) Compression modulus: The compression tester completely covers the sample surface, the compression rate is 2 mm / min, and the strain is compressed to 90%. The slope of the linear part of the compression stress-strain curve is extracted as the compression modulus. For details, please refer to GB / T 7757-2009.

[0199] (4) Density and porosity: Refer to GB / T 6343-2009. Then, the porosity P is calculated according to the formula P=(1-ρ′ / ρ)×100%; where ρ′ is the bulk density of the material, that is, the density of the adhesive layer measured in each embodiment; ρ is the density of the material, that is, the density of the adhesive layer in Comparative Example 1.

[0200] (5) Thermal conductivity: Refer to GB / T 10295-2008.

[0201] (6) Insulation temperature: A 2mm thick adhesive layer is used as the insulation pad. The insulation pad includes a first side and a second side that are set opposite to each other. The heating temperature of the first side is set to 200±3℃ and held for 5 minutes. The temperature of the second side is read. The lower the temperature of the second side, the better the insulation effect of the insulation pad.

[0202] The performance test results of the adhesive layers of Examples 1-26 and Comparative Examples 1-8 are shown in Table 2 below.

[0203] Table 2. Performance test results of adhesive layer

[0204]

[0205] Based on the above results, the density of the adhesive layer in Examples 1-26 is 0.019 g / cm³. 3 ~0.196g / cm 3 The thermal conductivity is 0.017 W / (m·K) to 0.05 W / (m·K). Under test conditions where the temperature of the first surface is 200±3℃, the temperature of the second surface can be maintained between 20℃ and 140℃. The heat insulation effect is significantly better than that of Comparative Example 1, indicating that the adhesive layer provided in this application has excellent heat insulation and protection effects. At the same time, the adhesive layers of Examples 1 to 26 have high bonding strength, low compression modulus, and high compression rebound rate, and also have excellent bonding performance and buffering rebound effect, realizing the integrated function of bonding, buffering and heat insulation.

[0206] A comparison of Examples 1-6 shows that with increasing compressed air dosage, density, thermal conductivity, and temperature of the second surface initially decrease significantly, then the change becomes gradual. A comparison of Examples 5 and 7-10 shows that with increasing foaming agent dosage, the temperature of the second surface initially decreases, then slightly increases. A comparison of Examples 5 and 11-15 shows that the temperature of the second surface decreases with increasing foaming agent dosage, but when the foaming agent dosage increases to 0.1 parts by weight or more, the decrease in temperature is not significant. A comparison of Examples 5 and 16-19 shows that with increasing surfactant dosage, the temperature of the second surface initially decreases, then increases. A comparison of Examples 5 and 20-26 shows that, with increasing TPU content, the temperature of the second side initially decreases significantly, then becomes less pronounced; the compressive modulus gradually increases, while the compression rebound rate gradually decreases. Conversely, with increasing SBS and SIS content, the compression rebound rate gradually increases. A good balance between thermal insulation and cushioning performance is achieved when the mass ratio of SBS, SIS, and TPU is 2:6:2. Therefore, using the adhesive layer of Example 5 can achieve excellent bonding, cushioning, and thermal insulation performance while minimizing raw material usage, thereby reducing costs.

[0207] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0208] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery, characterized in that, It includes multiple battery cells, with an adhesive layer disposed between at least two of the battery cells, the adhesive layer comprising a thermoplastic elastomer and having a cellular structure.

2. The battery according to claim 1, characterized in that, The pore size of the bubble structure is 0.1mm to 1mm, and the porosity is 80% to 99%.

3. The battery according to claim 1 or 2, characterized in that, The density of the adhesive layer is ≤0.2 g / cm³. 3 .

4. The battery according to claim 3, characterized in that, The density of the adhesive layer is ≤0.025 g / cm³. 3 .

5. The battery according to any one of claims 1 to 4, characterized in that, The thermal conductivity of the adhesive layer is ≤0.05W / (m·K).

6. The battery according to any one of claims 1 to 5, characterized in that, The adhesive layer satisfies at least one of the following conditions: (1) The adhesive strength of the adhesive layer is ≥0.65MPa; (2) The compression resilience of the adhesive layer is ≥55%; (3) The compressive modulus of the adhesive layer is ≤0.7MPa.

7. The battery according to any one of claims 1 to 6, characterized in that, The thermoplastic elastomer includes at least one of styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, thermoplastic polyurethane elastomers, polyester-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers. The styrene-based thermoplastic elastomers include at least one of styrene-butadiene-styrene triblock copolymers, hydrogenated styrene-butadiene-styrene triblock copolymers, styrene-isoprene-styrene triblock copolymers, and hydrogenated styrene-isoprene-styrene triblock copolymers. The olefin-based thermoplastic elastomers include at least one of ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer.

8. The battery according to claim 7, characterized in that, The thermoplastic elastomers include styrene-butadiene-styrene triblock copolymers, styrene-isoprene-styrene triblock copolymers, and thermoplastic polyurethane elastomers.

9. The battery according to claim 8, characterized in that, The weight ratio of the styrene-butadiene-styrene triblock copolymer, the styrene-isoprene-styrene triblock copolymer, and the thermoplastic polyurethane elastomer is (10~30):(50~70):(10~30).

10. The battery according to any one of claims 7 to 9, characterized in that, The thermoplastic elastomer satisfies at least one of the following conditions: (1) The number average molecular weight of the styrene-butadiene-styrene triblock copolymer is 100,000 to 120,000, and the weight percentage of butadiene is 60% to 80%; (2) The number average molecular weight of the styrene-isoprene-styrene triblock copolymer is 150,000 to 200,000, and the weight percentage of isoprene is 70% to 80%; (3) The number average molecular weight of the thermoplastic polyurethane elastomer is 10,000 to 15,000.

11. The battery according to any one of claims 1 to 10, characterized in that, The adhesive layer further includes at least one of tackifying resin, inorganic filler, and antioxidant.

12. The battery according to claim 11, characterized in that, The adhesive layer satisfies at least one of the following conditions: (1) The tackifying resin includes at least one of 145 rosin resin, 138 rosin resin, terpene resin, C5 / C9 copolymer petroleum resin, thermoplastic phenolic resin and polystyrene resin; (2) The weight ratio of the thermoplastic elastomer to the tackifying resin is 100:(20~40); (3) The inorganic filler includes at least one of calcium carbonate, barium sulfate and clay; (4) The particle size of the inorganic filler is 20nm~50nm; (5) The weight ratio of the thermoplastic elastomer to the inorganic filler is 100:(15~25); (6) The antioxidant includes at least one of 2,6-di-tert-butyl-p-cresol and 4,4′-bis(6-tert-butyl-resorcinol) sulfide; (7) The weight ratio of the thermoplastic elastomer to the antioxidant is 100: (0.3~0.5).

13. The battery according to any one of claims 1 to 12, characterized in that, The thickness of the adhesive layer is 0.5mm to 5mm.

14. A method for preparing a battery, characterized in that, Includes the following steps: A hot melt adhesive containing thermoplastic elastomer is melted to obtain a hot melt adhesive liquid; The hot melt adhesive liquid is foamed to obtain a foamed adhesive liquid; The battery is obtained by bonding at least two battery cells together using the foaming adhesive to form an adhesive layer with a pore structure between the at least two battery cells.

15. The method for preparing a battery according to claim 14, characterized in that, The adhesive layer has a pore diameter of 0.1 mm to 1 mm and a porosity of 80% to 99%.

16. The method for preparing a battery according to claim 14 or 15, characterized in that, The foaming process employs a combined foaming process that integrates physical and chemical foaming.

17. The method for preparing a battery according to claim 16, characterized in that, The combined foaming process includes the following steps: adding a foaming agent to the hot melt adhesive liquid and introducing compressed gas.

18. The method for preparing a battery according to claim 17, characterized in that, The mass-to-volume ratio of the thermoplastic elastomer to the compressed gas is 100g:(20L~300L).

19. The method for preparing a battery according to claim 18, characterized in that, The mass-to-volume ratio of the thermoplastic elastomer to the compressed gas is 100g:(100L~200L).

20. The method for preparing a battery according to any one of claims 17 to 19, characterized in that, The combined foaming process further includes the following steps: adding foaming aids and surfactants to the hot melt adhesive liquid.

21. The method for preparing a battery according to claim 20, characterized in that, The weight ratio of the thermoplastic elastomer, the foaming agent, the foaming aid, and the surfactant is 100:(2~15):(0.02~1):(0.1~1).

22. The method for preparing a battery according to claim 21, characterized in that, The weight ratio of the thermoplastic elastomer, the foaming agent, the foaming aid, and the surfactant is 100:(5~10):(0.1~0.6):(0.2~0.7).

23. The method for preparing a battery according to any one of claims 20 to 22, characterized in that, The combined foaming process satisfies at least one of the following conditions: (1) The foaming agent includes at least one of carbonate foaming agents, bicarbonate foaming agents, sulfonyl hydrazine foaming agents and azo foaming agents; (2) The foaming agent includes at least one of metal oxide and metal stearate; (3) The surfactant includes at least one of sodium dodecyl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate; (4) The compressed gas includes at least one of compressed air, compressed nitrogen and compressed carbon dioxide.

24. The method for preparing a battery according to any one of claims 14 to 23, characterized in that, The melting temperature of the melt treatment is 150℃~200℃.

25. An electrical appliance, characterized in that, The battery includes any one of claims 1 to 13, or a battery prepared by any one of claims 14 to 24.

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