Battery, battery pack, and energy storage system

Abstract

The present application provides a battery, a battery pack, and an energy storage system. The battery comprises: a casing; and a battery cell arranged in the casing. A support frame is arranged between at least one inner wall of the casing and the battery cell, the material of the support frame comprising a solid-solid phase change material so as to improve the consistency of the internal temperature of the battery.

Description

Batteries, battery packs and energy storage systems

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on February 7, 2024, with application number 202410173909.0 and application name “Batteries, Battery Packs and Energy Storage Systems”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of batteries, and specifically designs a battery, a battery pack, and an energy storage system. Background Art

[0004] Batteries generate heat during use. If this heat isn't dissipated promptly, the internal temperature of the battery will gradually rise. When the temperature inside the battery reaches a certain point, the SEI film decomposes, the separator melts, and the negative electrode reacts with the electrolyte. This, in turn, causes the positive electrode and electrolyte to decompose. This process continues to release heat and produce gas, potentially leading to thermal runaway, such as battery combustion and explosion. Furthermore, during the battery's charge and discharge cycles, temperature differences develop between different parts of the battery cell, particularly the winding core, affecting the battery's temperature consistency. This uneven cell temperature can easily lead to localized lithium deposition within the cell, reducing battery performance and lifespan. Localized lithium deposition can also cause short circuits within the cell, leading to thermal runaway. Existing heat dissipation methods typically involve installing a liquid cooling device external to the battery to dissipate heat. However, existing liquid cooling devices are typically located at the bottom of the battery, preventing the timely absorption of heat from the top and sides. Consequently, current heat dissipation devices cannot achieve uniform internal cell temperatures.

[0005] Summary of the Invention

[0006] The present application provides a battery, a battery pack, and an energy storage system to improve the consistency of the internal temperature of the battery, reduce local lithium plating, delay the occurrence of thermal runaway, and reduce the hazards of thermal runaway.

[0007] In a first aspect, the present application provides a battery comprising a housing and a battery cell disposed within the housing, wherein a support frame is disposed between at least one inner wall of the housing and the battery cell, and the support frame is made of a solid-solid phase change material.

[0008] The battery of the present application has a support frame provided between the battery cell and at least one inner wall of the shell, and the material of the support frame includes solid-solid phase change material, which can be mainly prepared by solid-solid phase change material. Since the solid-solid phase change material has the function of absorbing and releasing heat, the heat absorption and heat release function of the solid-solid phase change material can be used to improve the consistency of the temperature of the battery cell in the battery, reduce the capacity decay caused by local temperature rise of the battery cell, and reduce the occurrence of lithium precipitation problems caused by local low temperature of the battery cell. In addition, during the operation of the battery, when the temperature inside the battery rises from a low temperature to the phase transition point of the solid-solid phase change material, the support frame can absorb the heat generated by the battery cell during operation to reduce the temperature inside the battery, delay the occurrence of thermal runaway, or reduce the degree of thermal runaway damage, and even avoid thermal runaway caused by excessive temperature of the battery cell. When the ambient temperature drops and the temperature of the battery is lower than the phase transition point of the solid-solid phase change material, the solid-solid phase change material can release heat to increase the temperature inside the battery so that the battery cell operates at normal operating temperature. Therefore, the battery of the present application achieves thermal management of the battery cell by using a support frame containing solid-solid phase change material, thereby ensuring that the battery can operate at an appropriate temperature.

[0009] The support frame is provided between the load-bearing inner wall of the shell and the battery cell. A support member is provided between the load-bearing inner wall of the shell and the battery cell to reduce the contact between the battery cell and the shell, and avoid lithium deposition caused by gravity squeezing between the battery cell and the shell.

[0010] To achieve uniform absorption of heat around the battery cells, in an optional implementation, the support frame is provided between each inner wall of the housing and each surface of the battery cells. Since the support frame is provided between each inner wall of the housing and the battery cells, heat from all sides of the battery cells can be absorbed simultaneously, thereby further improving the temperature consistency within the battery cells, further reducing the occurrence of capacity attenuation caused by local temperature rise in the battery cells, and also reducing the occurrence of lithium deposition caused by local low temperature in the battery cells, allowing the battery cells to operate within the normal operating temperature range. At the same time, when the battery cells experience thermal runaway, the support frame can also consume some of the heat, reducing the degree of failure risk.

[0011] In addition, when support frames are provided on all four sides of the battery cell, since the support frames are provided between the housing and the battery cell, when the battery is placed on its side, that is, when the small surface of the battery is parallel to the placement surface and the battery pole is located on the side of the battery, the support frames can support the battery cell, preventing the battery cell from tilting when placed on its side and partially contacting the inner wall of the housing to cause lithium deposition, thereby reducing the chance of lithium deposition in the battery cell. When the battery is placed flat, that is, when the large surface of the battery is parallel to the placement surface, by providing support members around the battery cell, it is possible to prevent the electrolyte from contacting the explosion-proof valve and corroding the explosion-proof valve, thereby preventing corrosion and leakage, thereby improving the safety of the battery.

[0012] The multiple support frames arranged around the battery cells can be an integrated structure, which is more stable and easy to disassemble and install.

[0013] The support frame is formed of two or more types of solid-solid phase change materials, each with a different phase transition point. By configuring solid-solid phase change materials with different phase transition points, the heat absorption and heat release functions of the solid-solid phase change materials can be controlled at different temperatures, thereby achieving temperature control of the battery cells at different temperatures.

[0014] During the battery's charge and discharge process, the cells expand and contract. To prevent the support frame from affecting the cell's expansion, in one optional implementation, the support frame can be an elastic support frame. The elastic support member can elastically deform when the cell expands and is squeezed, thereby providing space for the cell to expand.

[0015] During the battery's charge and discharge process, as the cell expands with full charge, the interlayer spacing between the electrode plates within the cell decreases, causing the electrolyte to be squeezed out from both sides of the cell. When the cell discharges, the interlayer spacing is restored, and the electrolyte is reabsorbed into the gaps in the cell due to the wetting and adhesion forces. This change in the interlayer spacing between the electrode plates within the cell caused by charging and discharging can be likened to the cell's "breathing" effect. During battery use, electrolyte consumption occurs. When the electrolyte decreases, gravity increases the electrolyte reabsorption path at the top of the cell, thereby affecting battery performance. To reduce the electrolyte reabsorption path, in one optional implementation, the support frame can have a porous structure. When the support frame has a porous structure, during the battery charging process, the electrolyte squeezed out of the cell can be absorbed by the support frame. When the battery discharges, the electrolyte absorbed by the support frame can be reabsorbed into the cell at the nearest location. Since the support frame is arranged between the inner walls of the shell and the battery cell, it can achieve liquid retention in all directions, shorten the electrolyte back-absorption path, and avoid problems such as purple spots in a part of the battery cell due to insufficient electrolyte.

[0016] Among them, the organic solid-solid phase change material can be a polymer phase change material, such as at least one of polyethylene glycol, a composite material of ethylene-propylene-carbon nanotubes, a composite material of cellulose-polyethylene glycol and high-density polyethylene, and a polylactic acid-polyurethane composite material. In an optional implementation, the support frame can be formed by polymerizing monomers of the solid-solid phase change material in the battery. For example, during the assembly of the battery, the surface of the shell can be firstly formed with a support frame of the organic solid-solid phase change material through monomer self-polymerization, and then the battery cell can be assembled. Since the support frame is formed by self-polymerization, the distribution of the support frame in the shell is more uniform. After the shell and the battery cell are assembled, the electrolyte can be injected into the shell.

[0017] In an optional implementation, when the battery is a conventional liquid battery, that is, when the battery is filled with an electrolyte, in order to achieve rapid absorption of heat in the battery cell and reduce the heat inside the battery cell, a solid-solid phase change material can be provided in the battery cell. The solid-solid phase change material can be an organic solid-solid phase change material. The solid-solid phase change material can exist in the form of material particles or in the form of a solid-solid phase change material. Among them, the solid-solid phase change material can be added to the electrolyte or added to the electrode. Exemplarily, the presence of the solid-solid phase change material in the battery cell includes at least one of the following forms:

[0018] a) provided in the positive electrode material layer of the positive electrode sheet;

[0019] b) provided in the negative electrode material layer of the negative electrode sheet;

[0020] c) provided in the diaphragm;

[0021] d) provided between the positive electrode sheet and the diaphragm;

[0022] e) provided between the separator and the negative electrode sheet;

[0023] f) provided on the surface of the positive electrode sheet;

[0024] g) provided on the surface of the diaphragm;

[0025] h) is arranged on the surface of the negative electrode sheet.

[0026] When there are two or more battery cells, the solid-solid phase change material may also exist between two adjacent battery cells.

[0027] When the solid-solid phase change material exists in the form of a solid-solid phase variant, the solid-solid phase variant can exist in at least one of the following forms: long strips, branches, sheets, or a network. The solid-solid phase variant can be formed by polymerizing monomers of the solid-solid phase change material. To achieve liquid retention of the electrolyte within the battery cell and shorten the electrolyte reabsorption path, in an optional implementation, the solid-solid phase variant can have a porous structure. In addition to absorbing the internal heat of the battery cell, the porous solid-solid phase variant also has the ability to retain electrolyte, allowing the electrolyte to quickly infiltrate the electrode during charging. Due to the small spacing between the positive and negative electrode sheets of the battery cell, the size of the solid-solid phase variant can be micrometer- or nanometer-sized in the direction of the arrangement of the positive and negative electrode sheets. In addition, during the electrolyte reabsorption process, the electrolyte within the battery can flow from the rich area along the solid-solid phase variant to the lean area, achieving uniform electrolyte distribution and reducing the problem of lean electrolyte in a certain area of ​​the battery cell.

[0028] In another optional implementation of the present application, the battery is an all-solid-state battery. When the battery is an all-solid-state battery, the battery cell may include a positive electrode sheet, a solid electrolyte layer and a negative electrode sheet. Among them, the positive electrode sheet, the solid electrolyte layer and the negative electrode sheet are stacked in sequence. The solid electrolyte layer includes a solid electrolyte. The solid electrolyte can be used to achieve the transmission of active elements. In addition, the solid electrolyte layer may include a solid-solid phase change material, which is used to provide a heat absorption function for the solid electrolyte layer. The solid-solid phase change material can be mixed with the solid electrolyte to form a solid electrolyte layer. The solid-solid phase change material of the solid electrolyte layer can exist in the form of powder particles or in the form of solid-solid phase change. Among them, the addition ratio of the solid-solid phase change material in the solid electrolyte layer is based on not affecting the transmission of active elements in the solid-state battery.

[0029] Among them, when the battery is a solid-state battery, the solid-solid phase change material in the battery core can be set in the solid electrolyte layer and can also exist in the following forms:

[0030] a) provided in the positive electrode material layer of the positive electrode sheet;

[0031] b) provided in the negative electrode material layer of the negative electrode sheet;

[0032] c) provided between the positive electrode sheet and the solid electrolyte layer;

[0033] d) provided between the solid electrolyte layer and the negative electrode sheet;

[0034] e) provided on the surface of the positive electrode sheet;

[0035] f), provided on the surface of the solid electrolyte layer;

[0036] g) is arranged on the surface of the negative electrode sheet.

[0037] When there are two or more battery cells, the solid-solid phase change material may also exist between two adjacent battery cells.

[0038] The battery cell may contain two or more types of solid-solid phase change materials, each with a different phase transition point. By configuring solid-solid phase change materials with different phase transition points, the heat absorption and heat release functions of the solid-solid phase change materials can be controlled at different temperatures, thereby enabling temperature control of the battery cell at different temperatures.

[0039] In addition, when the battery is a solid-state battery, the solid electrolyte layer also includes a copolymer that has the ability to transport active elements and solid-solid phase change properties. The solid electrolyte may contain only the copolymer, or it may include both the copolymer and a traditional solid electrolyte. The copolymer may include structural unit A and structural unit B. Structural unit A is a structural unit for transporting active elements, and structural unit B is a structural unit for achieving solid-solid phase change. Structural unit A may be primarily formed by polymerizing monomers of traditional organic electrolytes. Structural unit B may be primarily formed by polymerizing monomers of organic solid-solid phase change materials.

[0040] In one implementation, the structural unit A includes at least one of the following structural units:

[0041] n is an integer greater than or equal to 1, and the hydrogen in the structural unit A may be substituted by at least one of a halogen, -OH, -NH2, an alkyl group having C1-C60 carbon atoms, an alkoxy group having C1-C60 carbon atoms, an aromatic group having C1-C60 carbon atoms, an arylene group having C1-C60 carbon atoms, an ether group having C1-C60 carbon atoms, an ester group having C1-C60 carbon atoms, or an alcoholamine group having C1-C60 carbon atoms;

[0042] Structural unit B includes at least one of the following structural units:

[0043] In the structural unit B, m and n are each independently selected from an integer greater than or equal to 1, R is a diphenylmethane group, and the hydrogen in the structural unit B can be replaced by at least one of a halogen, -OH, -NH2, an alkyl group having C1-C60 carbon atoms, an alkoxy group having C1-C60 carbon atoms, an aromatic group having C1-C60 carbon atoms, an arylene group having C1-C60 carbon atoms, an ether group having C1-C60 carbon atoms, an ester group having C1-C60 carbon atoms, or an alcoholamine group having C1-C60 carbon atoms.

[0044] The monomers forming the copolymer may include a first monomer and a second monomer. The first monomer and the second monomer may form a copolymer having a structural unit A and a structural unit B through copolymerization.

[0045] The first monomer may be selected from at least one of ethylene oxide, vinylidene fluoride, acrylonitrile, methyl methacrylate, hexafluoropropylene, and ethylene oxide.

[0046] The second monomer may be selected from at least one of a polyol compound, an olefin compound, a lactic acid compound, and an isocyanate compound.

[0047] In a second aspect, the present application provides a battery pack, which may include a case and a plurality of batteries according to the first aspect of the present application, wherein the plurality of batteries are connected in series or in parallel.

[0048] In a third aspect, the present application provides an energy storage system, which includes a power converter and at least one battery pack according to the second aspect of the present application; the power converter is used to convert the voltage output by the battery pack into power and output it to a power grid or a load, and / or, convert the voltage output by an external power supply into power and output it to the battery pack.

[0049] The technical effects that can be achieved in the second and third aspects mentioned above can be described with reference to the corresponding effects in the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG1 is a schematic structural diagram of a battery according to an embodiment;

[0051] FIG2 is a schematic side view of a battery according to an embodiment;

[0052] FIG3 is a schematic diagram of a side-placed structure of a battery according to an embodiment;

[0053] FIG4 is a schematic diagram of a top view of a battery according to an embodiment;

[0054] FIG5 is a schematic structural diagram of a battery in a flat state according to an embodiment;

[0055] FIG6 is a schematic diagram of the connection structure of an energy storage system.

[0056] Figure numerals: 1-shell; 11-pole; 12-explosion-proof valve; 13-small surface; 14-large surface; 2-battery cell; 20-tab; 21-positive electrode; 22-diaphragm; 23-negative electrode; 24-flat surface; 25-curved surface; 3-support frame; 4-solid-solid phase variation; 100-battery pack; 200-power converter; 300-grid; 400-load; 500-photovoltaic module. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0058] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "above", "the", and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0059] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0060] For ease of understanding, the following first explains the relevant terms in the embodiments of the present application.

[0061] A battery cell is the basic unit that enables battery operation. For liquid batteries, a battery cell may consist of a positive electrode material, a negative electrode material, and a separator. For solid-state batteries, a battery cell may consist of a positive electrode material, a negative electrode material, and a solid electrolyte. Battery cells can include stacked cores and wound cores. A stacked core is a stack of positive and negative electrode sheets and a separator. A wound core is a collection of positive and negative electrode sheets and a separator produced through a winding process.

[0062] A battery consists of a casing and cells. The casing encapsulates the cells, providing insulation and assembly. It is the smallest saleable unit of a product.

[0063] A battery pack includes at least one battery cell. Multiple batteries can be connected in series or parallel to achieve different output voltages and currents. In addition to batteries, a battery pack may also include control modules such as a battery management system.

[0064] Lithium deposition: During the charge and discharge process of the battery, active ions, such as lithium ions, cannot be embedded in the negative electrode material, and a silvery-white metal element will form on the surface of the negative electrode, which is called lithium deposition.

[0065] Sideways: The battery's terminals are parallel to the surface on which it is placed. In a rolled-core battery, when the battery is placed on its side, the curved corners of the roll will touch the inner wall of the battery case.

[0066] Thermal runaway refers to a chain reaction phenomenon related to heat, triggered by various factors. This chain reaction is accompanied by the generation of large amounts of heat and the emission of harmful gases, and cannot be effectively controlled. Battery thermal runaway often begins with the decomposition of the SEI film on the negative electrode of the battery cell, followed by the decomposition and melting of the separator, which causes a reaction between the negative electrode and the electrolyte. Subsequently, the positive electrode and electrolyte also decompose, triggering a large-scale internal short circuit in the battery, causing the electrolyte to burn, which can then spread to other cells, easily causing the entire battery pack to spontaneously combust or even explode.

[0067] Existing batteries typically dissipate heat by installing a heat sink externally, such as a liquid cooling plate at the bottom. However, the battery lacks internal heat dissipation elements, which prevents timely heat conduction during operation. The battery's interior near the liquid cooling plate dissipates heat faster and remains cooler, while areas farther from the plate dissipate heat more slowly and remain hotter. This can easily lead to uneven temperatures within the battery.

[0068] To address the above-mentioned issues, embodiments of the present application provide a battery. The battery of the present application provides a support frame primarily formed of a solid-solid phase change material between the battery housing and the battery cell. During battery operation, the support frame absorbs heat released by the battery cell, reducing the internal temperature of the battery cell. Alternatively, the heat release characteristics of the solid-solid phase change material are utilized to release heat within the battery, thereby effectively managing the battery's thermal state and improving the uniformity of the battery's internal temperature.

[0069] Figure 1 is a schematic diagram of the structure of a battery according to one embodiment. As shown in Figure 1, when the battery is a liquid battery, the battery includes a housing 1, a battery cell 2, and an electrolyte. The battery cell 2 is located within the housing 1. The housing is a rectangular parallelepiped structure, with its length along the x-direction shown in Figure 1, its width along the y-direction shown in Figure 1, and its height along the z-direction shown in Figure 1. The housing 1 includes a bottom plate, side plates, and a top plate. The bottom plate and top plate are arranged opposite each other, with the side plates arranged between the bottom plate and top plate. The top of the housing 1 has an opening in the height direction of the housing 1, and the top plate covers the opening of the housing 1 to form a closed storage space with the bottom plate and side plates. The battery cell 2 is a rectangular parallelepiped structure or a structure similar to a rectangular parallelepiped and is located within the storage space of the housing 1 to encapsulate the battery cell 2 and prevent electrolyte leakage. The top plate of the housing 1 is typically provided with poles 11, a positive pole and a negative pole. The two poles 11 are spaced apart along the length direction x of the housing 1 and are fixedly connected to the top plate. The tabs 20 of the battery cell 2 are divided into positive and negative tabs. One end of the positive tab is connected to the positive electrode sheet 21 of the battery cell 2, and the other end is connected to the positive electrode post. One end of the negative tab is connected to the negative electrode sheet 23 of the battery cell 2, and the other end is connected to the negative electrode post. The material of the housing 1 can be aluminum alloy, and its inner wall can be provided with an insulating film, such as Mylar film, to achieve insulation from the battery cell 2.

[0070] In order to achieve rapid absorption of heat in the battery cell 2, in an embodiment of the present application, a support frame 3 may be provided between at least one inner wall of the shell 1 and the battery cell 2. The support frame 3 may be provided between one inner wall of the shell 1 and the battery cell 2, or between two inner walls of the shell 1 and the battery cell 2, or between three inner walls of the shell 1 and the battery cell 2. Accordingly, the support frame 3 may be provided between all inner walls of the shell 1 and the battery cell 2. In order to support the battery cell 2, a support frame 3 is required to be provided between at least the load-bearing wall of the shell 1 and the battery cell 2. As shown in Figure 1, when the shell 1 is a rectangular parallelepiped structure, a support frame 3 is provided between each inner wall of the shell 1 and the battery cell 2, such as a support frame 3 is provided between the top plate of the shell 1 and the battery cell 2, between the side plate of the shell 1 and the battery cell 2, and between the bottom plate of the shell 1 and the battery cell 2. During battery operation, when the temperature inside the battery reaches the phase transition point of the solid-solid phase change material, the support frame 3 absorbs the heat generated by the battery cells 2 during operation. The support frame 3 then conducts heat, evenly distributing the heat within the support frame 3. Because the support frame 3 is positioned between the inner walls of the housing 1 and the battery cells 2, heat from all directions around the battery cells 2 within the battery is absorbed by the support frame 3, improving temperature consistency within the battery cells 2.

[0071] During the charge and discharge process of the battery, the battery cell 2 will expand and contract. Therefore, the support frame 3 in the battery of the embodiment of the present application is an elastic support member to provide expansion space for the contraction of the battery cell 2. During the charge and discharge process of the battery, as the battery cell 2 is fully charged and expanded, the interlayer spacing between the electrode pieces in the battery cell 2 decreases, causing part of the electrolyte to be squeezed out of the battery cell 2 and flow into the gap between the battery cell and the shell. When the battery cell 2 is discharged, the interlayer spacing is restored, and the electrolyte is re-absorbed into the gap of the battery cell 2 under the action of the wetting adhesion force. During this process, the electrolyte will be repeatedly absorbed or discharged from the battery cell 2, and the electrolyte will tend to accumulate at the bottom of the battery under the action of gravity, and the upper part of the battery is prone to the problem of purple spots due to lack of electrolyte. Therefore, in order to shorten the back-absorption path of the electrolyte, the support frame 3 can be a porous structure. The support frame 3 is set to a porous structure, which can achieve liquid retention performance for the electrolyte. After the electrolyte is squeezed out, it can enter the support frame 3 adjacent to it. When the battery cell 2 discharges and the electrolyte is reabsorbed, the electrolyte can enter the battery cell 2 from the adjacent support frame 3. Therefore, compared with the traditional battery structure, the electrolyte reabsorption path at the top of the battery cell 2 will be significantly shortened, thereby improving the cycle performance of the battery cell 2.

[0072] Among them, the material forming the support frame 3 may include a solid-solid phase change material. The solid-solid phase change material is mainly an organic solid-solid phase change material. The organic solid-solid phase change material can form the desired support frame structure through polymerization. In addition, the support frame 3 may also include inorganic solid-solid phase change particles to improve the flame retardancy of the battery. The support frame 3 of the present application can be formed by polymerizing polymerizable monomers of solid-solid phase change materials in the shell 1. Therefore, multiple support frames 3 in the shell 1 can be an integrated connection structure. After the support frame 3 is formed in the shell 1, the battery cell 2 and the shell 1 can be assembled.

[0073] The phase transition point of the solid-solid phase change material may be within the normal operating range of the battery, slightly above the maximum normal operating temperature of the battery, or near the maximum operating temperature of the battery. The normal operating temperature range of the battery may be the battery's designed operating temperature, which may be determined based on the battery type, battery safety design, and other factors. When the temperature within the battery reaches the phase transition point of the solid-solid phase change material, the molecular structure of the solid-solid phase change material may change to absorb and release heat.

[0074] Taking the normal operating temperature of a battery as an example, which is 25-45°C, the phase transition point of the solid-solid phase change material can be set to 40-45°C. When the temperature inside the battery exceeds the phase transition point of the solid-solid phase change material, the solid-solid phase change material absorbs heat through phase transition, reducing the temperature and temperature rise rate inside the battery, delaying the occurrence of battery thermal runaway and reducing the severity of the damage caused by thermal runaway. When the temperature inside the battery drops from a high temperature to the phase transition point of the solid-solid phase change material, the solid-solid phase change material releases heat through molecular structural changes, heating the battery cell and keeping the temperature inside the battery within the normal operating range as much as possible.

[0075] In another application scenario, when the battery is used in a high-temperature environment, such as a desert area, due to the high ambient temperature of the battery, the phase change point of the solid-solid phase change material can be controlled within the range of 60-70°C to avoid phase change when the battery is not in operation.

[0076] In another application scenario, when the battery is used in a low-temperature environment, such as in the extremely cold northern regions, the phase change point of the solid-solid phase change material can be controlled to be lower, so that the solid-solid phase change material is easy to generate heat, so that the battery temperature reaches the lowest operating temperature range, and the battery is prevented from stopping working due to excessively low temperature.

[0077] It is understood that the solid-solid phase change material forming the support frame can be one, two, or more than one. Different phase change materials can have different phase transition points. By adding solid-solid phase change materials with different phase transition points, different temperature controls can be achieved, allowing the battery to operate within the desired operating range, avoiding battery cell capacity degradation caused by excessively high battery temperatures or lithium deposition caused by excessively low battery temperatures.

[0078] The solid-solid phase change material may be, for example, at least one of polyvinyl alcohol, polyethylene glycol, a composite material of ethylene-propylene-carbon nanotubes, a composite material of cellulose bonded to polyethylene glycol and high-density polyethylene, and a polylactic acid-polyurethane composite material. Among them, the solid-solid phase change material with different phase change temperatures can be obtained by modifying the above materials. For example, the phase change temperature and rigidity of the material can be controlled by changing the chain length, side group type, etc. of the polymer molecules or monomers of the solid-solid phase change material to ensure that the battery undergoes a phase change before thermal runaway. The endothermic reaction during the phase change process is used to delay the internal temperature rise of the battery cell 2 and stabilize the temperature inside the battery cell 2. At the same time, part of the heat can be absorbed when the battery cell 2 experiences thermal runaway. In addition, in a low-temperature environment, the heat released by the solid-solid phase change material during the heat release process can be used to heat the battery cell to prevent lithium deposition due to low temperature.

[0079] In addition to being present in the support frame 3 between the battery cell 2 and the shell 1, the solid-solid phase change material can also be present in the internal structure of the battery cell. For example, the solid-solid phase change material is added to the positive electrode sheet or the negative electrode sheet during the preparation of the electrode sheet, the solid-solid phase change material can also be added during the preparation of the diaphragm, and can also be added to the electrolyte. By adding the solid-solid phase change material inside the battery cell, the heat inside the battery cell can be absorbed in time to avoid the accumulation of heat inside the battery cell. The solid-solid phase change material inside the battery cell can be an organic solid-solid phase change material or an inorganic solid-solid phase change material. The solid-solid phase change material can exist in the form of material particles or in the form of a solid-solid phase change variant. The solid-solid phase change variant can be an object with a certain structure formed by the polymerization of monomers of the solid-solid phase change material. When the solid-solid phase change material exists in the form of a solid-solid phase change variant, the solid-solid phase change variant can exist in at least one of the following forms: long strips, branches, sheets or meshes.

[0080] Exemplarily, the solid-solid phase change material exists in the battery core in at least one of the following forms:

[0081] a) In the positive electrode material layer of the positive electrode sheet: For example, the solid-solid phase change material can be mixed with the positive electrode active material to form the positive electrode material layer.

[0082] b) in the negative electrode material layer of the negative electrode sheet: for example, the solid-solid phase change material can be mixed with the negative electrode active material to form the negative electrode material layer.

[0083] c) provided in the diaphragm: For example, the solid-solid phase change material can be mixed with the raw materials for preparing the diaphragm to form a diaphragm with a solid-solid phase change function.

[0084] d) Disposed between the positive electrode sheet and the separator: For example, particles of solid-solid phase change material or solid-solid phase change variant can be dispersed and disposed between the positive electrode sheet and the separator.

[0085] e) Disposed between the separator and the negative electrode sheet: For example, particles of solid-solid phase change material or solid-solid phase change material can be dispersed and disposed between the negative electrode sheet and the separator.

[0086] f) provided on the surface of the positive electrode sheet: for example, the solid-solid phase change material or the solid-solid phase change agent may be adhered to the surface of the positive electrode sheet.

[0087] g) provided on the surface of the diaphragm: for example, the solid-solid phase change material or the solid-solid phase change agent may be adhered to the surface of the diaphragm.

[0088] h) provided on the surface of the negative electrode sheet: for example, the solid-solid phase change material or the solid-solid phase change material may adhere to the surface of the negative electrode sheet.

[0089] The solid-solid phase change material present in the liquid battery cell can be one, two, or more than one. Different phase change materials can have different phase transition points. By adding solid-solid phase change materials with different phase transition points, different temperature controls can be achieved, allowing the battery to operate within the desired operating range, avoiding cell capacity decay due to excessively high battery temperatures or lithium deposition due to excessively low cell temperatures.

[0090] Among them, when the battery is a liquid battery, the number of cells in the battery can be one, two, or more than two. When there are two or more cells in the battery, the solid-solid phase change material can also be present between two adjacent cells. When the number of cells is two or more, when the battery is in a flat state, as the electrolyte is consumed, there will be a problem of lack of electrolyte in the top cell. The presence of the support frame can serve as a storage unit for the electrolyte. During the charge and discharge process of the battery, it can absorb and release the electrolyte, thereby shortening the path for the electrolyte to be sucked back to the top cell and reducing the occurrence of the problem of broken bridge and lithium precipitation.

[0091] FIG2 is a schematic side view of the structure of a battery according to an embodiment. Referring to FIG1 and FIG2 , the battery cell 2 is a stacked core. The stacked core includes positive electrode sheets 21, separators 22, and negative electrode sheets 23 arranged alternately and stacked along the width direction of the housing 1 (the y direction shown in FIG2 ). The positive electrode sheets 21, separators 22, and negative electrode sheets 23 may be rectangular or square. Referring to FIG2 , the solid-solid phase change material within the battery cell 2 exists in the form of solid-solid phase changers 4. The solid-solid phase changers may be elastic phase changers. During battery charging, the solid-solid phase changers 4 may be squeezed and contracted, and during battery discharge, the solid-solid phase changers 4 may return to their original shape. The solid-solid phase changers 4 may be in the form of at least one of a strip, a branch, a sheet, or a mesh. In the arrangement direction of the electrode sheets, the size of the solid-solid phase changers 4 may be micrometer-scale or nanometer-scale, not exceeding the spacing between the electrode sheets and the separator 22.

[0092] The solid-solid phase transformer 4 can have a porous structure. This porous structure can enhance the electrolyte retention capability of the solid-solid phase transformer 4, allowing the electrolyte to quickly penetrate the electrode during charging. Furthermore, during electrolyte resorption, the electrolyte within the battery can flow from the liquid-rich area along the solid-solid phase transformer to the liquid-poor area, achieving uniform electrolyte distribution and reducing the risk of electrolyte starvation in a single area of ​​the battery cell 2.

[0093] When the battery is a solid-state battery, that is, the battery does not contain an electrolyte and a separator. The battery cell includes a positive electrode sheet, a solid electrolyte layer, and a negative electrode sheet, and the positive electrode sheet, the solid electrolyte layer, and the negative electrode sheet are alternately and stacked. The solid electrolyte layer includes a solid electrolyte. Among them, in a solid-state battery, the solid electrolyte can be an organic solid electrolyte. Organic solid electrolytes include but are not limited to polyvinyl alcohol (polyvinyl alcohol polymer, PVA), polyvinylidene chloride (PVDC), polypropylene oxide, polyethylene oxide (PEO), polyvinylidene difluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinylidene fluoride-hexafluoropropylene (HFP) copolymer (PVDF-HFP), etc., and polymers with certain similarities in molecular structure to the above materials. Among them, polyethylene oxide has become the main material of organic polymer solid electrolytes due to its good compatibility with metal lithium negative electrodes. Since polyethylene oxide (PEO) inherently contains no lithium, it requires pre-lithiation. Its lithium conduction mechanism is the induction of lithium ions by ether oxygen bonds or highly electronegative atoms, followed by the movement of lithium-rich segments in the amorphous region to achieve near-neighbor transfer of lithium ions. The ultimate effect is that lithium ions enter from one side of the polymer layer and exit from the other, enabling lithium ion charge and discharge transport. The higher the crystallinity of PEO after doping with lithium salts, the greater its strength, but the lower its lithium ion conductivity. Therefore, the appropriate degree of crystallinity can be reduced through inorganic particle doping, polymer grafting, copolymerization, cross-linking modification, and other methods.

[0094] In a solid-state battery, when a solid-solid phase change material is present inside the battery cell, it may be present in the solid electrolyte layer. In this case, the solid electrolyte layer may include a solid-solid phase change material and a solid electrolyte. The solid-solid phase change material in the solid electrolyte layer may be present in the form of powder particles or in the form of a solid-solid phase change variant. The form of the solid-solid phase change material is not specifically limited here. The addition ratio of the solid-solid phase change material in the solid electrolyte layer shall be such that it does not affect the transmission of active elements in the solid-state battery.

[0095] Similarly, when the battery is a solid-state battery, the solid-solid phase change material in the battery cell can be provided in the solid electrolyte layer or in the following forms:

[0096] a) provided in the positive electrode material layer of the positive electrode sheet;

[0097] b) provided in the negative electrode material layer of the negative electrode sheet;

[0098] c) provided between the positive electrode sheet and the solid electrolyte layer;

[0099] d) provided between the solid electrolyte layer and the negative electrode sheet;

[0100] e) provided on the surface of the positive electrode sheet;

[0101] f), provided on the surface of the solid electrolyte layer;

[0102] g) is arranged on the surface of the negative electrode sheet.

[0103] Similarly, the solid-state phase change material present in the battery cell of a solid-state battery can be one, two, or more than one. Different phase change materials can have different phase transition points. By adding solid-state phase change materials with different phase transition points, different temperature controls can be achieved, allowing the battery to operate within the desired operating range, avoiding problems such as cell capacity decay caused by excessively high battery temperatures or lithium deposition caused by excessively low cell temperatures.

[0104] Among them, the solid-solid phase change material in the solid electrolyte layer can exist in the form of a copolymer with a solid-solid phase change function in addition to the form of a pure substance. When the solid electrolyte layer contains a copolymer with a solid-solid phase change function, the copolymer can also have the function of transmitting active elements and realize the transmission of active ions such as lithium, sodium, potassium, calcium, and magnesium. Therefore, in the battery of the embodiment of the present application, the solid electrolyte layer can not only realize the conventional ion transmission function, but also play the role of phase change heat absorption. When the battery cell 2 generates heat during the working process, it can be absorbed by the solid electrolyte layer and conducted to the support frame 3, and then conducted to the shell 1 by the support frame 3 to achieve the effect of temperature balance of the battery cell 2.

[0105] In one embodiment, the copolymer may include structural unit A and structural unit B. Structural unit A is a structural unit for transporting active elements, and structural unit B is a structural unit for achieving solid-solid phase transition. Thus, the copolymer can simultaneously have the functions of transporting active elements and undergoing solid-solid phase transition.

[0106] The structural unit A may be, for example, at least one of the following structural units:

[0107] In structural unit A, n is an integer greater than or equal to 1, and the hydrogen in the structural unit A may be substituted by at least one of halogen, -OH, -NH2, a C1-C60 alkyl group, a C1-C60 alkoxy group, a C1-C60 aromatic group, a C1-C60 arylene group, a C1-C60 ether group, a C1-C60 ester group, or a C1-C60 alcoholamine group. The halogen may be an element such as F, Cl, Br, or I.

[0108] The structural unit B may be, for example, at least one of the following structural units:

[0109] In the structural unit B, m and n are each independently selected from an integer greater than or equal to 1, R is a diphenylmethane group, and the hydrogen in the structural unit B can be replaced by at least one of a halogen, -OH, -NH2, an alkyl group having C1-C60 carbon atoms, an alkoxy group having C1-C60 carbon atoms, an aromatic group having C1-C60 carbon atoms, an arylene group having C1-C60 carbon atoms, an ether group having C1-C60 carbon atoms, an ester group having C1-C60 carbon atoms, or an alcoholamine group having C1-C60 carbon atoms.

[0110] For example, when preparing a copolymer, the copolymer can be formed by copolymerizing two monomers, namely a first monomer and a second monomer. The first monomer and the second monomer can form a copolymer having structural units A and B through copolymerization.

[0111] For example, the first monomer may be selected from at least one of ethylene oxide, vinylidene fluoride, acrylonitrile, methyl methacrylate, hexafluoropropylene, and ethylene oxide, and the second monomer may be selected from at least one of polyol compounds, olefin compounds, lactic acid compounds, and isocyanate compounds.

[0112] It is understood that when preparing a copolymer, the phase transition temperature and rigidity of the copolymer can be controlled by changing the chain length of the copolymer molecules or the monomers forming the copolymer, the type of side groups, etc. through grafting or copolymerization.

[0113] As an example, a polymerizable monomer of a solid-solid phase change material can be copolymerized with a polymerizable monomer of a solid electrolyte such as PEO or PVDC to form a solid electrolyte with the following structure, which exhibits both solid-solid phase change properties and the ability to transport active elements. The polymerizable monomer of the solid-solid phase change material is represented by PCM.

[0114] Similarly, a solid electrolyte having the following structural formula can also be formed:

[0115] Among them, the hydrogen in the above structure can also be replaced by at least one of halogen, -OH, -NH2, alkyl group with C1-C60 carbon atoms, alkoxy group with C1-C60 carbon atoms, aromatic group with C1-C60 carbon atoms, arylene group with C1-C60 carbon atoms, ether group with C1-C60 carbon atoms, ester group with C1-C60 carbon atoms, or alcoholamine group with C1-C60 carbon atoms.

[0116] The connection structure in the above reaction formula is only an example. The arrangement and combination of each segment are different, and a variety of molecular structures may appear during the copolymerization process.

[0117] In the copolymers of the embodiments of the present application, the phase transition temperature and molecular rigidity of the copolymers can be regulated by modifying the molecular structure of the copolymers. The specific implementation methods are as follows: 1) changing the steric hindrance: adding symmetrical side chains on both sides of the molecular segments of the copolymer to increase the distance between the main chains, reduce the steric hindrance between the molecular chains, and reduce the rigidity; 2) changing the alkyl chain length to change the phase change enthalpy. By regulating the phase transition temperature, the phase transition can occur when the temperature of the battery cell is higher or lower than the appropriate operating temperature range, thereby generating endothermic / exothermic phenomena and achieving the purpose of thermal management. At the same time, the rigidity adjustment of the solid-solid phase change molecules can regulate the elasticity of the support frame and the solid-solid phase change body, so that it can both support the battery cell and be compressed.

[0118] In traditional batteries, due to the influence of gravity, when the battery is placed on its side, the battery cell will tilt inside the shell, and the bottom corner of the battery cell will tilt and abut against the shell. As the electrode expands, it will interfere with the shell, causing lithium deposition and deteriorating the cycle life.

[0119] Continuing with Figure 1 , the battery cell 2 can be either a stacked or wound core. In the stacked configuration, the battery cell 2 includes a positive electrode sheet 21, a separator 22, and a negative electrode sheet 23, alternately stacked along the width of the housing 1. In the wound core configuration, the positive electrode sheet 21, the negative electrode sheet 23, and the separator 22 are wound together.

[0120] Figure 3 is a schematic diagram of the side-placed structure of a battery in an embodiment. Referring to Figures 1, 2 and 3, during the battery cycle, the thickness of the core stack will increase due to expansion. Usually, a certain expansion gap is reserved between the core stack and the inner wall of the shell 1 to allow the core stack to expand. However, when the expansion size of the core stack exceeds the reserved space, stress concentration is prone to occur at the four corners of the positive electrode sheet 21 and the negative electrode sheet 23 in the core stack, resulting in lithium deposition. The battery in the embodiment of the present application, by providing a support frame 3 between the shell 1 and the battery cell 2, when the battery is placed on its side, that is, when the small surface 13 of the battery is parallel to the placement surface, the support frame 3 can prevent it from abutting against the shell 1. When the battery cell 2 is deformed during the charge and discharge process, the support frame 3 may also be deformed accordingly.

[0121] FIG4 is a schematic diagram of the top structure of a battery according to an embodiment. As shown in FIG4 , the battery core 2 is a winding core. The winding core can be formed by winding a positive electrode sheet 21, a separator 22 and a negative electrode sheet 23 stacked in sequence into a columnar structure. After winding, the columnar structure can be extruded to form a structure similar to a rectangular parallelepiped. The winding core includes two oppositely arranged end faces, which are faces perpendicular to the winding direction. The circumferential side surface between the two end faces includes two oppositely arranged flat surfaces 24 and two oppositely arranged curved surfaces 25, and the two flat surfaces 24 and the two curved surfaces 25 are connected. Referring to FIG1 , the end face is arranged along the height direction of the shell 1 (the z direction shown in FIG1 ), the flat surface 24 is arranged along the width direction of the shell 1 (the y direction shown in FIG1 ), and the curved surface 25 is arranged along the length direction of the shell 1 (the x direction shown in FIG1 ). The lugs 20 of the winding core are drawn out from one end face of the winding core and are respectively connected to the poles 11 of the top plate. Referring to Figure 3, when the battery is placed on its side, gravity causes the bottom corners of the core to come into contact with the casing 1. The core expands during cycling, but the corners are squeezed and restrained by the casing 1, preventing them from releasing. This leads to severe lithium deposition in these corners, resulting in cycling failure and a shortened battery life.

[0122] In this application, by providing an elastic gap between the shell and the battery cell, when the core expands during charging and discharging, the support frame can deform accordingly, providing space for the core to expand, reducing the degree of compression of the core corners, reducing the risk of lithium deposition, and avoiding the occurrence of short circuits between the core and the inner wall of the shell, thereby improving the safety of the battery. When the core is placed on its side as shown in Figure 4, the support frame can support and limit the core, and the curved surface 25 can avoid contact with the inner wall of the shell, thereby preventing the occurrence of lithium deposition.

[0123] Figure 5 is a schematic diagram of a horizontally placed battery structure according to one embodiment. As shown in Figure 5 , when the battery is placed horizontally, with its large surface 14 parallel to the placement surface, the height of the electrolyte within the battery can exceed the height of the explosion-proof valve 12. When a support frame is installed between the battery housing and the battery cell, it can prevent the electrolyte from infiltrating the explosion-proof valve 12, reducing the risk of electrolyte corrosion and, consequently, the risk of leakage.

[0124] In summary, the battery of the embodiment of the present application has the following advantages:

[0125] 1) By setting up a support frame made of solid-solid phase change material, the heat absorption and release phenomenon during the phase change process is used to delay the temperature rise inside the battery cell, thereby achieving thermal management and alleviating the problem of continuous heat generation and thermal runaway during battery use.

[0126] 2) During the operation of the battery, by setting up a porous support frame, the problem of insufficient electrolyte above the battery cell can be alleviated, which is caused by the increase in electrolyte consumption, the longer electrolyte back-absorption path and the longer back-absorption time, the intensified "breathing" effect of the battery cell, and the tendency of electrolyte shortage above the battery cell.

[0127] 3) By polymerizing the polymerizable monomers at low temperature in the shell, the phase change material can be evenly dispersed and polymerized inside the battery. The phase change material is used to implement temperature control, making the temperature distribution inside the battery cell more balanced, thereby alleviating the problem of temperature differences between different parts of the battery cell, which leads to reduced consistency.

[0128] 4) In the application scenario where the battery is placed on its side, a support frame can be set to prevent the battery cell from tilting, which can alleviate the lithium plating problem easily caused by the interference between the battery cell and the shell.

[0129] The above description only uses lithium batteries as an example, but the battery of the present application is not limited to lithium batteries, and can also be a sodium battery, potassium battery, magnesium battery or calcium battery.

[0130] Based on the same technical concept, an embodiment of the present application provides a battery pack comprising multiple batteries according to the embodiments of the present application. The multiple batteries can be connected in series or in parallel via external connectors. Since the battery pack includes all the technical features of the battery, it also includes all the beneficial effects of the battery, which will not be elaborated here.

[0131] Based on the same technical concept, an embodiment of the present application provides an energy storage system. Figure 6 is a schematic diagram of the connection structure of an energy storage system. As shown in Figure 6, the energy storage system includes the battery pack 100 and the power converter 200 of the present application, and the power converter 200 is used to convert the voltage output by the battery pack 100 into power and output it to the power grid 300 or the external load 400, and / or, the power converter 200 is used to convert the voltage output by the external power supply into power and output it to the battery pack 100. Among them, the battery pack 100 can be connected to the photovoltaic module 500, and the photovoltaic module 500 is used to charge the battery pack 100. Since the energy storage system includes the battery pack 100, and the battery pack 100 includes all the technical features of the battery, the energy storage system also includes all the beneficial effects of the battery, which will not be repeated here.

[0132] In summary, the battery, battery pack and energy storage system provided in the present application can improve the thermal conductivity of the battery cells, reduce the probability of thermal runaway, and reduce the degree of squeezing of the corners of the upright stacked core battery and the corners of the side-placed rolled core battery during use, thereby reducing the risk of lithium plating and increasing the service life of the battery.

[0133] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A battery, characterized in that: The invention comprises a shell and a battery cell arranged in the shell, a support frame is provided between at least one inner wall of the shell and the battery cell, and the material of the support frame comprises solid-solid phase change material.

2. The battery according to claim 1, characterized in that The support frame is provided between the load-bearing inner wall of the shell and the battery core.

3. The battery according to claim 1 or 2, characterized in that The support frame is provided between each inner wall of the shell and each surface of the battery core.

4. The battery according to any one of claims 1 to 3, characterized in that The support frame is a porous structure.

5. The battery according to any one of claims 1 to 4, characterized in that: The support frame is an elastic support frame.

6. The battery according to any one of claims 1 to 5, characterized in that: The battery core comprises a positive electrode sheet, a separator and a negative electrode sheet which are stacked, and the solid-solid phase change material is arranged in the battery core.

7. The battery according to claim 6, characterized in that A solid-solid phase changer is provided in the battery core. The material of the solid-solid phase changer includes the solid-solid phase change material. The solid-solid phase changer is in at least one of a strip shape, a branch shape, a sheet shape or a mesh shape.

8. The battery according to claim 7, characterized in that The solid-solid phase variant is a porous structure.

9. The battery according to any one of claims 1 to 5, characterized in that: The battery core includes a positive electrode sheet, a solid electrolyte layer and a negative electrode sheet which are stacked, and the solid electrolyte layer includes a solid electrolyte.

10. The battery according to claim 9, characterized in that The solid electrolyte layer further includes the solid-solid phase change material.

11. The battery according to any one of claims 1 to 10, characterized in that: The solid-solid phase change material includes at least one of polyethylene glycol, an ethylene-propylene-carbon nanotube composite material, a cellulose-polyethylene glycol-high-density polyethylene composite material, and a polylactic acid-polyurethane composite material.

12. The battery according to any one of claims 1 to 5, characterized in that: The battery core comprises a positive electrode sheet, a solid electrolyte layer and a negative electrode sheet which are stacked. The solid electrolyte layer comprises a copolymer. The copolymer has the performance of transmitting active elements and the performance of solid-solid phase change.

13. The battery according to claim 12, characterized in that The copolymer comprises structural unit A and structural unit B; The structural unit A comprises at least one of the following structural units: In the structural unit A, n is an integer greater than or equal to 1, and the hydrogen in the structural unit A may be substituted by at least one of F, -OH, -NH2, an alkyl group having C1-C60 carbon atoms, an alkoxy group having C1-C60 carbon atoms, an aromatic group having C1-C60 carbon atoms, an arylene group having C1-C60 carbon atoms, an ether group having C1-C60 carbon atoms, an ester group having C1-C60 carbon atoms, or an alcoholamine group having C1-C60 carbon atoms; The structural unit B includes at least one of the following structural units: In the structural unit B, m and n are each independently selected from an integer greater than or equal to 1, R is a diphenylmethane group, and the hydrogen in the structural unit B can be replaced by at least one of F, -OH, -NH2, an alkyl group having C1-C60 carbon atoms, an alkoxy group having C1-C60 carbon atoms, an aromatic group having C1-C60 carbon atoms, an arylene group having C1-C60 carbon atoms, an ether group having C1-C60 carbon atoms, an ester group having C1-C60 carbon atoms, or an alcoholamine group having C1-C60 carbon atoms.

14. The battery according to claim 12, characterized in that The comonomers of the copolymer include a first monomer and a second monomer, The first monomer is selected from at least one of ethylene oxide, vinylidene fluoride, acrylonitrile, methyl methacrylate, hexafluoropropylene, and ethylene oxide; The second monomer is selected from at least one of polyol compounds, olefin compounds, lactic acid compounds, and isocyanate compounds. A sort of.

15. The battery according to any one of claims 1 to 14, characterized in that: The support frame is formed of two or more types of solid-solid phase change materials, and different solid-solid phase change materials have different phase change points.

16. The battery according to any one of claims 6 to 15, characterized in that: There are two or more types of solid-solid phase change materials arranged in the battery core, and different solid-solid phase change materials have different phase change points.

17. A battery pack, characterized in that: The battery pack includes a plurality of batteries according to any one of claims 1 to 16, and the plurality of batteries are connected in series or in parallel.

18. An energy storage system, characterized in that: The energy storage system includes a power converter and at least one battery pack as described in claim 17; the power converter is used to convert the voltage output by the battery pack into power and output it to the power grid or load, and / or, convert the voltage output by an external power supply into power and output it to the battery pack.

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