Battery cell and preparation method therefor, and electric device

Abstract

Disclosed in the embodiments of the present application are a battery cell and a preparation method therefor, and an electric device. The battery cell comprises: an electrode assembly and an aluminum-plastic film configured to accommodate the electrode assembly, wherein the aluminum-plastic film comprises a first phase-change material and a second phase-change material. The first phase-change material has a phase-change temperature T1 satisfying: 40°C≤T1≤60°C, and the second phase-change material has a phase-change temperature T2 satisfying: 80°C≤T2≤140°C. The technical solution of the present application can effectively control the temperature of the battery, thereby reducing the risk of high-temperature aging and thermal runaway, and thus improving the operational performance and safety of the battery.

Description

Battery cells and their preparation methods, and electrical devices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510479711.X, filed on April 16, 2025, entitled “Battery Cell and Method for Preparation Thereof, Electrical Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and more specifically, to a battery cell, a method for preparing the same, and an electrical device thereof. Background Technology

[0004] With increasing environmental pollution, the new energy industry is attracting more and more attention. Within the new energy industry, battery technology is a crucial factor in its development.

[0005] The development of battery technology requires consideration of various design factors, such as energy density, cycle life, capacity, and reliability. Battery operating temperature is a crucial factor affecting battery performance and safety; therefore, effectively controlling battery temperature is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

[0006] This application is made in view of the above-mentioned issues, and its purpose is to effectively control the temperature of the battery, reduce the risk of high-temperature aging and thermal runaway, thereby improving the performance and safety of the battery.

[0007] To achieve the above objectives, this application provides a battery cell, a method for preparing the same, and an electrical device thereof.

[0008] In a first aspect, a battery cell is provided, comprising: an electrode assembly; and an aluminum-plastic film for accommodating the electrode assembly. The aluminum-plastic film includes a first phase change material and a second phase change material. The phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

[0009] In this embodiment, the aluminum-plastic film used to house the electrode assembly includes a first phase change material and a second phase change material. On one hand, since the normal operating temperature of a typical battery cell generally does not exceed 60°C, a phase change material with a phase change temperature between 40°C and 60°C is selected as the first phase change material. During the temperature rise of the battery cell, when the temperature reaches the phase change temperature of the first phase change material, the first phase change material undergoes a phase change and absorbs heat to lower the temperature of the battery cell, allowing it to operate at its normal operating temperature and preventing aging at high temperatures, thereby improving the battery cell's performance. On the other hand, the separator in a typical battery cell shrinks when it reaches approximately 140°C, causing contact between the positive and negative electrodes and generating a large amount of heat, potentially leading to thermal runaway. A phase change material with a phase change temperature between 80°C and 140°C is selected as the second phase change material. During the continuous rise of the battery cell temperature, approaching thermal runaway, when the temperature reaches the phase change temperature of the second phase change material, the second phase change material undergoes a phase change and absorbs heat to lower the temperature of the battery cell, reducing the risk of thermal runaway and thus improving the safety performance of the battery cell. Therefore, the technical solution of this application effectively controls the temperature of the battery cell by adding a first phase change material and a second phase change material with different phase change temperatures to the aluminum-plastic film. This can reduce the risk of high-temperature aging of the battery cell, improve the performance of the battery cell, and reduce the risk of thermal runaway of the battery cell, thereby improving the safety performance of the battery cell.

[0010] In one possible implementation, the first phase change material and the second phase change material are solid-solid phase change materials.

[0011] In the above scheme, the phase change material in the aluminum-plastic film is a solid-solid phase change material. During the use of the battery cell, when the temperature of the battery cell reaches the phase change temperature of the phase change material, the phase change material undergoes a solid-solid phase change to absorb heat and cool the battery cell. The phase change material remains solid, thus not affecting the structural morphology of the aluminum-plastic film and ensuring the structural stability of the aluminum-plastic film.

[0012] In one possible implementation, the first phase change material includes at least one of neopentyl glycol, trimethylolpropane, and 2-amino-2-methyl-1,3-propanediol; and the second phase change material includes at least one of trimethylolethane, trimethylolaminomethane, and trimethylolaminoethane.

[0013] In one possible implementation, the mass ratio of the first phase change material to the second phase change material is 2:8 to 8:2.

[0014] In one possible implementation, the aluminum-plastic film includes an outer protective layer, a metal layer, and a heat-sealing layer, wherein the heat-sealing layer, the metal layer, and the outer protective layer are sequentially disposed along a direction away from the electrode assembly, and the outer protective layer includes a first phase change material and a second phase change material.

[0015] The outer protective layer is located on the outermost side of the aluminum-plastic film. The outer protective layer contains a first phase change material and a second phase change material. When the first phase change material and / or the second phase change material undergo a phase change and absorb heat, causing the temperature of the battery cell to drop below the phase change temperature of the first phase change material and / or the second phase change material, the first phase change material and / or the second phase change material will switch back to their original state and release heat. Because the outer protective layer is located on the outermost side of the aluminum-plastic film, the released heat will be transferred to the external environment and will not be released into the battery cell, thus preventing the temperature of the battery cell from rising again.

[0016] In one possible implementation, the outer protective layer further includes a protective material, which includes at least one of thermoplastic polyester and thermoplastic resin, wherein the ratio of the sum of the masses of the first phase change material and the second phase change material to the mass of the protective material is 6:4 to 9:1.

[0017] The outer protective layer includes thermoplastic polyester and / or thermoplastic resin, which gives the aluminum-plastic film good impact resistance, puncture resistance, heat resistance, abrasion resistance and insulation, and protects the metal layer from scratches, so as to ensure the stability and safety of the battery cells in various operating environments.

[0018] In one possible implementation, the thermoplastic polyester comprises a polyester resin, which includes at least one of polyethylene, polypropylene, and nylon.

[0019] In one possible implementation, the aluminum-plastic film further includes a first adhesive layer and a second adhesive layer, wherein the first adhesive layer is disposed between the outer protective layer and the metal layer, and the second adhesive layer is disposed between the metal layer and the outer protective layer, and the first adhesive layer and / or the second adhesive layer and / or the heat-sealing layer include the first phase change material and the second phase change material.

[0020] In one possible implementation, the thickness D1 of the outer protective layer satisfies: 23μm≤D1≤27μm, and / or the thickness D2 of the metal layer satisfies: 38μm≤D2≤42μm, and / or the thickness D3 of the heat-sealing layer satisfies: 78μm≤D3≤82μm, and / or the thickness D4 of the first adhesive layer satisfies: 2μm≤D4≤4μm, and / or the thickness D5 of the second adhesive layer satisfies: 2μm≤D5≤4μm.

[0021] In a second aspect, a method for preparing a battery cell is provided, comprising: preparing an aluminum-plastic film; and accommodating an electrode assembly in the aluminum-plastic film to prepare the battery cell; wherein the aluminum-plastic film comprises a first phase change material and a second phase change material, the phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

[0022] The above-mentioned method for preparing battery cells is relatively simple and has low complexity. Furthermore, the aluminum-plastic film of the prepared battery cells includes a first phase change material and a second phase change material, which can effectively control the battery temperature, reduce the risk of high-temperature aging and thermal runaway, thereby improving the battery's performance and safety.

[0023] In one possible implementation, the preparation of the aluminum-plastic film includes: providing a metal layer; preparing a heat-sealing layer on one side surface of the metal layer; mixing a first phase change material and a second phase change material to obtain a slurry for an outer protective layer; and coating the slurry for the outer protective layer onto the other side surface of the metal layer to prepare the aluminum-plastic film.

[0024] In one possible implementation, the step of preparing a heat-sealing layer on one side surface of the metal layer includes: mixing the first phase change material and the second phase change material to obtain a slurry for the heat-sealing layer; and applying the slurry for the heat-sealing layer to one side surface of the metal layer to prepare the heat-sealing layer.

[0025] Thirdly, an electrical device is provided, comprising a battery cell as described in the first aspect and any possible implementation thereof, and / or a battery cell obtained according to the preparation method of the second aspect. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0027] Figure 1 is a schematic diagram of the structure of an aluminum-plastic film according to an embodiment of this application;

[0028] Figure 2 is a schematic structural diagram of a battery cell according to an embodiment of this application;

[0029] Figure 3 is a flowchart of a method for preparing a battery cell according to an embodiment of this application;

[0030] Figure 4 is a schematic structural diagram of a battery according to an embodiment of this application;

[0031] Figure 5 is a schematic structural diagram of an electrical device according to an embodiment of this application. Detailed Implementation

[0032] The battery cell and its preparation method, as well as the embodiments of the electrical device, of this application have been described in detail with reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0033] The "range" disclosed in this application is defined by 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 and can be arbitrarily combined; 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 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 "ab" 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 "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0034] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0035] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0036] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may 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.

[0037] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0038] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0039] In some embodiments, the battery cell in this application can be a metal battery. Specifically, the metal battery may include lithium metal secondary batteries, sodium metal batteries, or magnesium metal batteries, etc. This application does not limit this.

[0040] Typically, a battery cell includes a positive electrode, a negative electrode, an electrolyte, and a separator. During the charging and discharging process, active ions move back and forth between the positive and negative electrodes, inserting and extracting. The electrolyte acts as a conductor between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through; for example, the separator can be a membrane.

[0041] The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, charge / discharge rate, and reliability. Battery operating temperature is a crucial factor affecting battery performance and safety. For example, continuous operation at high temperatures can lead to battery aging and shorten its lifespan; conversely, thermal runaway can cause a continuous rise in battery temperature, compromising its safety. Therefore, effectively controlling battery temperature is a critical technical challenge that urgently needs to be addressed in battery technology.

[0042] In view of this, this application provides a battery cell, including an electrode assembly and an aluminum-plastic film for housing the electrode assembly. The aluminum-plastic film includes a first phase change material and a second phase change material with different phase change temperatures. Specifically, the phase change temperature of the first phase change material is between 40°C and 60°C. The normal operating temperature of a battery generally does not exceed 60°C. During the process of battery cell temperature rise, when the battery cell temperature reaches the phase change temperature of the first phase change material, the first phase change material undergoes a phase change and absorbs heat to reduce the temperature of the battery cell, allowing the battery cell to operate at its normal operating temperature and preventing aging at high temperatures, thereby improving the battery cell's performance. The phase change temperature of the second phase change material is between 80°C and 140°C. Generally, the separator in a battery cell shrinks when it reaches around 140°C, causing contact between the positive and negative electrodes and generating a large amount of heat, potentially leading to thermal runaway. Therefore, during the process of battery cell temperature continuously rising and approaching thermal runaway, when the battery cell temperature reaches the phase change temperature of the second phase change material, the second phase change material undergoes a phase change and absorbs heat to reduce the temperature of the battery cell, reducing the risk of thermal runaway and thus improving the safety performance of the battery cell.

[0043] [Battery cell]

[0044] This application provides a battery cell including an electrode assembly and an aluminum-plastic film for housing the electrode assembly.

[0045] The aluminum-plastic film includes a first phase change material and a second phase change material. The phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

[0046] Phase transition temperature is the critical temperature at which a substance transitions between different phases. It should be understood that in the embodiments of this application, the phase transition of the first phase change material and the second phase change material is a reversible phase transition. A reversible phase transition refers to a phase change that occurs between two phases at a certain temperature and phase equilibrium pressure. This phase transition occurs at the saturated vapor pressure of the substance and under isothermal and isobaric conditions. During a reversible phase transition, the substance can completely revert to its original state.

[0047] For example, the first phase change material and the second phase change material are solid-solid phase change materials.

[0048] The phase change material in aluminum-plastic film is a solid-solid phase change material. During the use of the battery cell, when the temperature of the battery cell reaches the phase change temperature of the phase change material, the phase change material undergoes a solid-solid phase change to absorb heat and cool the battery cell. The phase change material remains solid, thus not affecting the structural morphology of the aluminum-plastic film and ensuring the structural stability of the aluminum-plastic film.

[0049] Generally, the normal operating temperature of a battery cell does not exceed 60°C. Therefore, in this embodiment, a phase change material with a phase change temperature between 40°C and 60°C is selected as the first phase change material. During the process of battery cell temperature increase, when the battery cell temperature reaches the phase change temperature of the first phase change material, the first phase change material undergoes a phase change and absorbs heat to reduce the temperature of the battery cell. This allows the battery cell to operate at its normal operating temperature, preventing aging at high temperatures and improving the performance of the battery cell.

[0050] For example, the phase transition temperature T1 of the first phase change material can be 40°C, 42°C, 45°C, 50°C, 53°C, 55°C, 57°C, 60°C, or a value within the range obtained by any combination of the above two values.

[0051] For example, the first phase change material may include at least one of neopentyl glycol, trimethylolpropane, and 2-amino-2-methyl-1,3-propanediol.

[0052] The phase transition temperature of neopentyl glycol is 40℃ and the phase transition enthalpy is 70 J / g; the phase transition temperature of trimethylolpropane is 55℃ and the phase transition enthalpy is 100 J / g; and the phase transition temperature of 2-amino-2-methyl-1,3-propanediol is 57℃ and the phase transition enthalpy is 171 J / g.

[0053] Phase transition enthalpy refers to the enthalpy change of a substance during a phase transition process under isothermal and isobaric conditions without any non-volume work, i.e., the heat absorbed or released.

[0054] Generally, the separator in a battery cell shrinks when it reaches around 140°C, causing the positive and negative electrodes to come into contact and generate a large amount of heat, potentially leading to thermal runaway. Therefore, in this embodiment, a phase change material with a phase change temperature between 80°C and 140°C is selected as the second phase change material. As the battery cell temperature continues to rise and approaches thermal runaway, when the battery cell temperature reaches the phase change temperature of the second phase change material, the second phase change material undergoes a phase change and absorbs heat, thereby reducing the temperature of the battery cell, lowering the risk of thermal runaway, and improving the safety performance of the battery cell.

[0055] For example, the phase transition temperature T2 of the second phase change material can be 80℃, 85℃, 90℃, 95℃, 100℃, 110℃, 120℃, 130℃, 135℃, 140℃, or a value within the range obtained by any combination of the above two values.

[0056] For example, the second phase change material includes at least one of tris(hydroxymethyl)ethane, tris(hydroxymethyl)aminomethane, and tris(hydroxymethyl)aminoethane.

[0057] The phase transition temperature of tris(hydroxymethyl)ethane is 80℃ and the phase transition enthalpy is 100 J / g; the phase transition temperature of tris(hydroxymethyl)aminomethane is 134℃ and the phase transition enthalpy is 260 J / g; the phase transition temperature of tris(hydroxymethyl)aminoethane is 134℃ and the phase transition enthalpy is 270 J / g.

[0058] In this embodiment, the aluminum-plastic film 10 includes a first phase change material and a second phase change material with different phase change temperatures, which can effectively control the temperature of the battery cells at different temperature stages. On the one hand, it can control the battery cells to be at their normal operating temperature, preventing them from aging at high temperatures and thus improving their performance. On the other hand, when the battery cells continue to heat up, it can reduce their temperature, thereby reducing the risk of thermal runaway and improving their safety performance.

[0059] In some embodiments, the mass ratio of the first phase change material to the second phase change material is 2:8 to 8:2.

[0060] For example, the mass ratio of the first phase change material and the second phase change material can be 2:8, 3:7, 4:6, 4:5, 5:5, 6:4, 7:3, 8:2, or a ratio within the range obtained by any combination of the above two ratios.

[0061] Figure 1 is a schematic diagram of the structure of an aluminum-plastic film according to an embodiment of this application. As shown in Figure 1, the aluminum-plastic film 10 includes an outer protective layer 13, a metal layer 12, and a heat-sealing layer 11.

[0062] The electrode assembly is housed in the aluminum-plastic film 10, and the heat-sealing layer 11, the metal layer 12 and the outer protective layer 13 are sequentially arranged in the direction away from the electrode assembly.

[0063] In some embodiments, the outer protective layer 13 includes a first phase change material and a second phase change material.

[0064] The outer protective layer 13 is located on the outermost side of the aluminum-plastic film 10. The outer protective layer 13 contains a first phase change material and a second phase change material. When the first phase change material and / or the second phase change material undergo a phase change and absorb heat, causing the temperature of the battery cell to drop below the phase change temperature of the first phase change material and / or the second phase change material, the first phase change material and / or the second phase change material will switch back to their original state and release heat. Because the outer protective layer 13 is located on the outermost side of the aluminum-plastic film 10, the released heat will be transferred to the external environment and will not be released into the battery cell, thus preventing the temperature of the battery cell from rising again.

[0065] In some embodiments, the outer protective layer 13 further includes a protective material, which includes at least one of thermoplastic polyester and thermoplastic resin, and the ratio of the sum of the masses of the first phase change material and the second phase change material to the mass of the protective material is 6:4 to 9:1.

[0066] For example, the ratio of the sum of the masses of the first phase change material and the second phase change material to the mass of the protective material can be 6:4, 7:3, 8:2, 9:1, or a ratio within the range obtained by any combination of the above two ratios.

[0067] The outer protective layer 13 includes thermoplastic polyester and / or thermoplastic resin, which enables the aluminum-plastic film 10 to have good impact resistance, puncture resistance, heat resistance, friction resistance and insulation, and protects the metal layer 12 from scratches, so as to ensure the stability and safety of the battery cell in various usage environments.

[0068] In some embodiments, the thermoplastic polyester includes polyester resin, and the thermoplastic resin includes at least one of polyethylene, polypropylene, and nylon.

[0069] In some embodiments, the heat-sealing layer 11 includes a first phase change material and a second phase change material.

[0070] As an example, the heat-sealing layer 11 includes a first sub-heat-sealing layer 111 and a second sub-heat-sealing layer 112. The first sub-heat-sealing layer 111 includes a heat-adhesive resin (e.g., polypropylene), antioxidants, slip agents, antistatic agents, acid-resistant agents, and solvent-resistant agents, etc. The second sub-heat-sealing layer 112 may include an acid-modified polyolefin, such as an ethylene-propylene copolymer modified with unsaturated carboxylic acids, which can enhance the adhesion between the heat-sealing layer 11 and the metal layer 12.

[0071] In some embodiments, the first sub-heat-sealing layer 111 and / or the second sub-heat-sealing layer 112 include a first phase change material and a second phase change material.

[0072] As an example, the first sub-heat-sealing layer 111 includes a first phase change material and a second phase change material, while the second sub-heat-sealing layer 112 does not include the first phase change material and the second phase change material.

[0073] As an example, the second sub-heat-sealing layer 112 includes a first phase change material and a second phase change material, while the first sub-heat-sealing layer 111 does not include the first phase change material and the second phase change material.

[0074] As an example, the first sub-heat-sealing layer 111 and the second sub-heat-sealing layer 112 include a first phase change material and a second phase change material.

[0075] As an example, the metal layer 12 comprises aluminum. The metal layer 12 can prevent external water vapor from penetrating into the aluminum-plastic film 10.

[0076] As an example, a chemical conversion treatment layer 14 is provided between the metal layer 12 and the heat-sealing layer 11. The chemical conversion treatment layer 14 can be formed by reacting chromate with the surface of the aluminum metal layer 12 to improve the adhesion of the surface of the aluminum metal layer 12 and prevent corrosion of the aluminum metal layer 12.

[0077] In some embodiments, the aluminum-plastic film 10 further includes a first adhesive layer and a second adhesive layer. The first adhesive layer is disposed between the heat-sealing layer 11 and the metal layer 12 for bonding the heat-sealing layer 11 and the metal layer 12. The second adhesive layer is disposed between the metal layer 12 and the outer protective layer 13 for bonding the metal layer 12 and the outer protective layer 13. The first adhesive layer and / or the second adhesive layer include a first phase change material and a second phase change material.

[0078] As an example, the first adhesive layer includes a first phase change material and a second phase change material, while the second adhesive layer does not include the first phase change material and the second phase change material.

[0079] As an example, the second adhesive layer includes a first phase change material and a second phase change material, while the first adhesive layer does not include the first phase change material and the second phase change material.

[0080] As an example, the first adhesive layer and the second adhesive layer include a first phase change material and a second phase change material.

[0081] In some embodiments, as shown in FIG1, the thickness of the outer protective layer 13 is D1, and D1 satisfies: 23μm≤D1≤27μm.

[0082] For example, D1 can be 23μm, 24μm, 25μm, 26μm, 27μm, or a value within the range obtained by any combination of the above two values.

[0083] In some embodiments, as shown in FIG1, the thickness of the metal layer 12 is D2, and D2 satisfies: 38μm≤D2≤42μm.

[0084] For example, D2 can be 38μm, 39μm, 40μm, 41μm, 42μm, or a value within the range obtained by any combination of the above two values.

[0085] In some embodiments, as shown in FIG1, the thickness of the heat-sealing layer 11 is D3, and D3 satisfies: 78μm≤D3≤82μm.

[0086] For example, D3 can be 78μm, 79μm, 80μm, 81μm, 82μm, or a value within the range obtained by any combination of the above two values.

[0087] In some embodiments, the thickness D4 of the first adhesive layer (not shown in the figure) satisfies: 2μm≤D4≤4μm.

[0088] For example, D4 ​​can be 2μm, 2.5μm, 3μm, 3.5μm, 4μm, or a value within the range obtained by any combination of the above two values.

[0089] In some embodiments, the thickness D5 of the second adhesive layer (not shown in the figure) satisfies: 2μm≤D5≤4μm.

[0090] For example, D5 can be 2μm, 2.5μm, 3μm, 3.5μm, 4μm, or a value within the range obtained by any combination of the above two values.

[0091] 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. The battery cell can be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, a magnesium-ion battery, etc.

[0092] Figure 2 is a schematic diagram of a battery cell according to an embodiment of this application. For example, as shown in Figure 2, the battery cell 3 is a square battery cell. The battery cell 3 may include an outer packaging 31, which can be used to encapsulate the electrode assembly 32 and the electrolyte (not shown in the figure). Exemplarily, the outer packaging 31 can be a flexible packaging bag, such as an aluminum-plastic film 10.

[0093] The electrode assembly 32 can be made from a positive electrode, a negative electrode, and a separator through a winding process or a stacking process.

[0094] In some embodiments, the electrode assembly 32 includes an electrode assembly body 321 and a tab 322 extending from the electrode assembly body 321.

[0095] In some embodiments, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0096] [Positive electrode plate]

[0097] 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.

[0098] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0099] In some embodiments, the positive 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 substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0100] In some embodiments, the positive electrode active material may be a known battery positive electrode active material. As an example, the positive electrode active material may include at least one of the following materials: lithium 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 battery positive electrode active materials 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, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as 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 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 )), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0101] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0102] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0103] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0104] During the charging and discharging process of a battery, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of cathode materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. When the cathode material is applied to the battery system, the molar Li content changes after charge-discharge cycles.

[0105] In the examples of cathode materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0106] [Negative electrode plate]

[0107] The negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0108] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0109] 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 polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0110] In some embodiments, the negative electrode film layer may optionally include a binder. The binder may be selected from at least one 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).

[0111] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0112] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na) or lithium carboxymethyl cellulose (CMC-Li)).

[0113] 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 (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0114] [Electrolytes]

[0115] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel-like, or entirely solid.

[0116] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0117] Electrolyte salts may include one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0118] Solvents may include one or more of the following: ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, 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.

[0119] The electrolyte may also optionally include negative electrode film-forming additives, positive electrode film-forming additives, and performance additives that can improve certain battery performance, such as performance additives that improve battery overcharge performance, battery high temperature or low temperature performance, etc.

[0120] [Isolation Component]

[0121] The separator is used to isolate the positive electrode and the negative electrode. 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.

[0122] The material of the separator can be selected from one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film; there are no particular restrictions. When the separator is a multi-layer composite film, the materials of each layer can be the same or different; there are no particular restrictions.

[0123] Positive electrode, negative electrode and separator can be made into electrode assembly by winding process or stacking process.

[0124] [Preparation methods for battery cells]

[0125] Figure 3 is a schematic diagram of a method for preparing a battery cell according to an embodiment of this application. Referring to Figure 3, the method 300 for preparing a battery cell may include the following steps.

[0126] Step 310: Prepare aluminum-plastic film;

[0127] Step 320: The electrode assembly is housed in an aluminum-plastic film to prepare a single battery cell.

[0128] The aluminum-plastic film includes a first phase change material and a second phase change material. The phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

[0129] In some embodiments, preparing an aluminum-plastic film includes: providing a metal layer; preparing a heat-sealing layer on one side surface of the metal layer; mixing a first phase change material and a second phase change material to obtain a slurry for an outer protective layer; and coating the slurry for the outer protective layer onto the other side surface of the metal layer to prepare an aluminum-plastic film.

[0130] In some embodiments, preparing a heat-sealing layer on one side surface of a metal layer includes: mixing a first phase change material and a second phase change material to obtain a slurry for the heat-sealing layer; and applying the slurry for the heat-sealing layer to one side surface of the metal layer to prepare the heat-sealing layer.

[0131] In some embodiments, the preparation method 300 further includes: perforating the aluminum-plastic film before accommodating the electrode assembly in the aluminum-plastic film.

[0132] Punching refers to the process of punching a hole in an aluminum-plastic film to accommodate electrode components during the production of a battery cell, using a molding die under heating.

[0133] The above-mentioned method for preparing battery cells is relatively simple and has low complexity. Furthermore, the aluminum-plastic film of the prepared battery cells includes a first phase change material and a second phase change material, which can effectively control the battery temperature, reduce the risk of high-temperature aging and thermal runaway, thereby improving the battery's performance and safety.

[0134] [Battery]

[0135] This application provides a battery, including the battery cells described in the above embodiments. Figure 4 is a schematic diagram of the structure of a battery according to an embodiment of this application. As shown in Figure 4, the battery 5 may include multiple battery cells 3 to meet different power usage requirements. The shape of the battery cell 3 in this application embodiment can be set according to actual applications. For example, the battery cell 3 can be a cuboid as shown in Figure 2, or it can be a cylinder or other shape different from that shown in Figure 2. This application embodiment is not limited to this.

[0136] It should be understood that, as shown in FIG. 4, the battery 5 in this embodiment may further include a housing 51, which can be used to accommodate multiple battery cells 3. The housing 51 in this embodiment has a hollow internal structure, and the multiple battery cells 3 are accommodated within the housing 51. The housing 51 may include two parts, referred to herein as a first housing portion 511 and a second housing portion 512, which are fastened together. The shapes of the first housing portion 511 and the second housing portion 512 can be determined according to the shape of the components accommodated internally, for example, according to the shape of the combination of the multiple battery cells 3 accommodated internally. At least one of the first housing portion 511 and the second housing portion 512 has an opening. For example, as shown in Figure 4, the first housing portion 511 and the second housing portion 512 can both be hollow cuboids with one open face. The openings of the first housing portion 511 and the second housing portion 512 are opposite to each other, and the first housing portion 511 and the second housing portion 512 are interlocked to form a housing 51 with a closed cavity, which can be used to accommodate multiple battery cells 3. The multiple battery cells 3 are connected in parallel, series, or mixed and placed inside the housing 51 formed by the interlocking of the first housing portion 511 and the second housing portion 512.

[0137] For example, unlike what is shown in Figure 4, only one of the first housing portion 511 and the second housing portion 512 may be a hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 512 as a hollow cuboid with one opening, and the first housing portion 511 as a plate-shaped example, then the first housing portion 511 covers the opening of the second housing portion 512 to form a housing 51 with a closed chamber, which can be used to accommodate multiple battery cells 3.

[0138] Battery cells 3 can be directly assembled into battery 5, or they can be first assembled into battery modules, and then multiple battery modules can be assembled into battery 5.

[0139] [Electrical appliances]

[0140] This application provides an electrical device, including the battery described in the above embodiments.

[0141] Figure 5 is a schematic diagram of an electrical device according to an embodiment of this application. As shown in Figure 5, this application provides an electrical device 6, including the battery in the above embodiment.

[0142] Alternatively, the electrical device may also be an energy storage device, a lighting device, a spacecraft, etc., as is the case in the embodiments of this application.

[0143] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0144] [Examples and Comparative Examples]

[0145] 1. Preparation of aluminum-plastic film

[0146] Aluminum-plastic film 1:

[0147] Preparation of the metal layer: The surface of the aluminum foil is treated to remove oil and oxides, and the surface of the aluminum foil is passivated with chromate. Finally, the aluminum foil is dried to obtain the metal layer with a thickness of 40 μm.

[0148] Preparation of the heat-sealing layer: Anhydride-modified polypropylene is coated onto one side of the metal layer by extrusion and cured at 40℃~50℃ for 48 hours to obtain the heat-sealing layer with a thickness of 80μm.

[0149] Preparation of the outer protective layer: The first phase change material 2-amino-2-methyl-1,3-propanediol, the second phase change material tris(hydroxymethyl)aminoethane, and the protective material nylon were mixed using a high-speed mixer at a mass ratio of 3.1:3.9:3. The mixing temperature was controlled at 220℃, the speed of the high-speed mixer was 150 r / min, and the mixing time was 7 h. The uniformly mixed material was then extruded and coated onto the other side of the metal layer using a melt extruder to form an outer protective layer with a thickness of 25 μm.

[0150] Aluminum-plastic film 2-9: The preparation of aluminum-plastic film 2-9 is similar to that of aluminum-plastic film 1. The difference is that the phase change material in the outer protective layer is different during the preparation of aluminum-plastic film 2-9, as detailed in Table 1.

[0151] Aluminum-plastic film 10-12: The preparation of aluminum-plastic film 10-12 is similar to that of aluminum-plastic film 1. The difference is that in the preparation process of aluminum-plastic film 10-12, the mass ratios of the first phase change material, the second phase change material and the protective material are 4:5:1, 3.6:4.4:2 and 2.7:3.3:4, respectively.

[0152] Aluminum-plastic film 13-14: The preparation of aluminum-plastic film 13-14 is similar to that of aluminum-plastic film 1. The difference is that the phase change material in the outer protective layer is different during the preparation of aluminum-plastic film 13-14, as detailed in Table 1.

[0153] The preparation of the metal layer and heat-sealing layer of aluminum-plastic film 15 is similar to that of aluminum-plastic film 1. The difference is that the outer protective layer of aluminum-plastic film 15 does not include phase change material, but only protective material.

[0154] [Example 1]

[0155] (1) Aluminum-plastic film

[0156] The aluminum-plastic film used is the aluminum-plastic film 1 prepared as described above.

[0157] (2) Preparation of positive electrode sheet

[0158] Lithium nickel cobalt manganese oxide (LiNi) is used as the positive electrode active material. 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black, and binder PVDF are mixed in a mass ratio of 98:1:1 and dissolved in solvent N-methylpyrrolidone (NMP). After thorough mixing, a positive electrode slurry is prepared. The positive electrode slurry is then subjected to a concentration of approximately 25 mg / cm³. 2 The load is evenly coated on the two opposite surfaces of the positive current collector aluminum foil. After drying, cold pressing and cutting, a rectangular positive electrode sheet of 40mm*50mm is formed.

[0159] (3) Preparation of negative electrode sheet

[0160] A 50μm thick lithium foil is rolled onto one side of a 12μm thick copper foil and then cut into a rectangular negative electrode sheet of 41mm*51mm.

[0161] (4) Separation membrane: Conventional polyethylene membrane is used.

[0162] (5) Preparation of electrolyte: Lithium bis(fluorosulfonyl)imide (LiFSI) and dimethyl ethylene glycol (DME) are mixed evenly at a mass ratio of 748:867 to obtain an electrolyte with a concentration of 4 mol / L of LiFSI.

[0163] (6) Preparation of lithium metal battery: 19 positive electrode sheets and 20 negative electrode sheets are matched and separated by the separator to form an electrode assembly. An internal heating film is installed on one side of the electrode assembly and wrapped in an aluminum-plastic film bag to form a stacked dry cell cell. 3g of the prepared electrolyte is then injected, and the aluminum-plastic film bag is vacuum-sealed to obtain the lithium metal battery.

[0164] The battery cells of Examples 2-12 and Comparative Examples 1-3 were prepared using methods similar to those of the battery cell of Example 1, except that different aluminum-plastic films were used (Aluminum-plastic film 1-12 was used in Examples 1-12, and aluminum-plastic film 13-15 was used in Comparative Examples 1-3), as detailed in Table 1. Performance parameters of Examples 1-12 and Comparative Examples 1-3 are shown in Table 1.

[0165] Table 1. Product parameters and performance parameters of Examples 1-12 and Comparative Examples 1-3

[0166] In Table 1, t represents the thermal runaway resistance time of a single battery cell.

[0167] The following is a brief description of the testing methods for the physicochemical and performance parameters involved in the embodiments of this application. It should be understood that the following testing methods are only examples, and other testing methods known in the art can also be used for testing.

[0168] 1. Thermal runaway resistance time test

[0169] The thermal runaway resistance time test for lithium metal batteries can be conducted with reference to the national standard GB 38031-2020 "Safety Requirements for Power Batteries for Electric Vehicles". Specifically, the lithium metal battery is placed at a test temperature that meets the above national standard for testing, and the time from the start of the test to the triggering of thermal runaway is recorded. This time is the thermal runaway resistance time of the battery.

[0170] 2. Cyclic performance test

[0171] At 25°C, the lithium metal battery was charged at a constant current of 0.2C to a voltage of 4.3V, then charged at a constant voltage of 4.3V until the current ≤0.05C, allowed to stand for 5 minutes, and then discharged at a constant current of 1C to a voltage of 2.8V. This constitutes one charge-discharge cycle, and the discharge capacity at this point is recorded as the discharge capacity of the battery in its first cycle. This charge-discharge cycle was repeated, and the number of cycles corresponding to when the battery retains 80% of its capacity was calculated.

[0172] The capacity retention rate (%) of the battery after N cycles at 25℃ = (discharge capacity of the battery in the Nth cycle / discharge capacity of the battery in the first cycle) × 100%.

[0173] 3. Confirmation of phase transition temperature and phase transition enthalpy of phase change materials

[0174] Using a differential scanning calorimeter (DSC), under programmed temperature control, the same power value was input to both the phase change material (PCM) under test and the blank control group. The relationship between the power difference between the output power values ​​of the PCM and the blank control group and temperature was measured. During phase change, PCM exhibits endothermic or exothermic phenomena, and the DSC curve will show characteristic endothermic or exothermic peaks. Based on these peaks, the phase change temperature of the PCM can be determined, and the phase change enthalpy can be obtained from the area of ​​the exothermic peak.

[0175] 4. Confirmation of phase change materials

[0176] (1) Characterization of the structure of phase change materials

[0177] The phase change material in aluminum-plastic film was tested using an X-ray diffractometer in accordance with the national standard GB / T 5618-2014 to characterize the structure of the phase change material.

[0178] (2) Chemical element and content testing of phase change materials

[0179] Elemental content can be tested using inductively coupled plasma atomic emission spectrometry according to US EPA 6010D. In addition, atomic absorption spectrometry, spectrophotometry, titration, gravimetric methods, and other methods can also be used for testing.

[0180] 5. Dimensional Measurement

[0181] The thickness of each layer of the aluminum-plastic film can be measured using a micrometer.

[0182] Based on the results of Examples 1, 6, and 9 and Comparative Example 1, it can be seen that by simultaneously adding the first phase change material and the second phase change material to the aluminum-plastic film, the battery cell not only has good cycle performance, but also has a longer time to resist thermal runaway, resulting in higher safety performance.

[0183] Based on the results of Examples 1-3 and Comparative Example 2, it can be seen that by simultaneously adding the first phase change material and the second phase change material to the aluminum-plastic film, the battery cell not only has a longer time to resist thermal runaway, but also has good cycle performance, thus improving the performance of the battery cell.

[0184] Based on the results of Examples 1-12 and Comparative Example 3, it can be seen that by adding a first phase change material and a second phase change material to the aluminum-plastic film, the battery cell has both good cycle performance and a long thermal runaway resistance time, and the battery's performance and safety are significantly improved.

[0185] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A battery cell, characterized in that, include: Electrode assembly; An aluminum-plastic film is used to accommodate the electrode assembly. The aluminum-plastic film includes a first phase change material and a second phase change material. The phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

2. The battery cell according to claim 1, characterized in that, The first phase change material and the second phase change material are solid-solid phase change materials.

3. The battery cell according to claim 2, characterized in that, The first phase change material includes at least one of neopentyl glycol, trimethylolpropane, and 2-amino-2-methyl-1,3-propanediol; the second phase change material includes at least one of trimethylolethane, trimethylolaminomethane, and trimethylolaminoethane.

4. The battery cell according to any one of claims 1 to 3, characterized in that, The mass ratio of the first phase change material to the second phase change material is 2:8 to 8:

2.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The aluminum-plastic film includes an outer protective layer, a metal layer, and a heat-sealing layer. The heat-sealing layer, the metal layer, and the outer protective layer are arranged sequentially along the direction away from the electrode assembly. The outer protective layer includes a first phase change material and a second phase change material.

6. The battery cell according to claim 5, characterized in that, The outer protective layer further includes a protective material, which includes at least one of thermoplastic polyester and thermoplastic resin, and the ratio of the sum of the masses of the first phase change material and the second phase change material to the mass of the protective material is 6:4 to 9:

1.

7. The battery cell according to claim 6, characterized in that, The thermoplastic polyester includes polyester resin, and the thermoplastic resin includes at least one of polyethylene, polypropylene, and nylon.

8. The battery cell according to any one of claims 5 to 7, characterized in that, The aluminum-plastic film further includes a first adhesive layer and a second adhesive layer. The first adhesive layer is disposed between the heat-sealing layer and the metal layer, and the second adhesive layer is disposed between the metal layer and the outer protective layer. The first adhesive layer and / or the second adhesive layer and / or the heat-sealing layer include the first phase change material and the second phase change material.

9. The battery cell according to claim 8, characterized in that, The thickness D1 of the outer protective layer satisfies: 23μm≤D1≤27μm, and / or the thickness D2 of the metal layer satisfies: 38μm≤D2≤42μm, and / or the thickness D3 of the heat-sealing layer satisfies: 78μm≤D3≤82μm, and / or the thickness D4 of the first adhesive layer satisfies: 2μm≤D4≤4μm, and / or the thickness D5 of the second adhesive layer satisfies: 2μm≤D5≤4μm.

10. A method for preparing a single battery cell, characterized in that, include: Preparation of aluminum-plastic film; The electrode assembly is housed in the aluminum-plastic film to prepare the battery cell; The aluminum-plastic film includes a first phase change material and a second phase change material. The phase change temperature T1 of the first phase change material satisfies: 40℃≤T1≤60℃, and the phase change temperature T2 of the second phase change material satisfies: 80℃≤T2≤140℃.

11. The preparation method according to claim 10, characterized in that, The preparation of the aluminum-plastic film includes: Provide a metal layer; A heat-sealing layer is prepared on one side surface of the metal layer; The first phase change material and the second phase change material are mixed to obtain a slurry for the outer protective layer; The slurry of the outer protective layer is applied to the other side surface of the metal layer to prepare the aluminum-plastic film.

12. The preparation method according to claim 11, characterized in that, The preparation of a heat-sealing layer on one side surface of the metal layer includes: The first phase change material and the second phase change material are mixed to obtain the slurry of the heat-sealing layer; The heat-sealing layer is prepared by applying the slurry of the heat-sealing layer to one side surface of the metal layer.

13. An electrical appliance, characterized in that, Includes battery cells according to any one of claims 1 to 9, and / or battery cells prepared by the preparation method according to any one of claims 10 to 12.

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