Battery apparatus and electrical apparatus

Abstract

The present application provides a battery apparatus and an electrical apparatus. The battery apparatus comprises a battery assembly and a fixing assembly. The battery assembly comprises an elastic member and a battery cell, the battery cell comprises two first surfaces opposite one another in a first direction, and the elastic member abuts against the battery cell and covers the first surfaces. The fixing assembly comprises two first fixing members arranged opposite to each other in the first direction, and the battery assembly is sandwiched between the two first fixing members. The battery apparatus comprises a 0% state of charge and a 100% state of charge. In the 0% state of charge, the elastic member has a first compression displacement in the first direction, and the elastic member abuts against the battery cell with a first compression force of F1. In the 100% state of charge, the elastic member has a second compression displacement in the first direction, and the elastic member abuts against the battery cell with a second compression force of F2. The second compression displacement is greater than the first compression displacement, and (F2-F1) / F1 is 0 to 0.1.

Description

Battery devices and electrical appliances

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application 202411547099.7, entitled "Battery Device and Power Consumption Device," filed on October 31, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of batteries, specifically to a battery device and an electrical device. Background Technology

[0004] Battery devices are characterized by high capacity and long lifespan, and are therefore widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0005] As batteries are used more widely, the requirements for battery performance are becoming increasingly stringent, and the cycle life of battery devices still needs to be further improved. Summary of the Invention

[0006] This application is made in view of the above-mentioned problems, and its purpose is to provide a battery device and an electrical device that can improve the stress uniformity of battery cells, thereby improving the cycle life of the battery device.

[0007] In a first aspect, embodiments of this application propose a battery device, which includes a battery assembly and a fixing assembly. The battery assembly includes an elastic member and a battery cell. The battery cell includes two first surfaces facing each other along a first direction. The elastic member abuts against the battery cell and covers the first surfaces. The fixing assembly includes two first fixing members arranged opposite each other along the first direction, with the battery assembly sandwiched between the two first fixing members. The battery device includes a 0% state of charge and a 100% state of charge. In the 0% state of charge, the elastic member has a first compression displacement along the first direction, and the elastic member abuts against the battery cell with a first compression force F1. In the 100% state of charge, the elastic member has a second compression displacement along the first direction, and the elastic member abuts against the battery cell with a second compression force F2. The second compression displacement is greater than the first compression displacement, and (F2-F1) / F1 is 0 to 0.1.

[0008] Therefore, when the above conditions are met in the embodiments of this application, the first compression force and the second compression force are kept basically constant, the force on the battery cell is kept basically constant, and the solid-solid interface can make stable and good contact, thereby improving the electrochemical performance of the battery device and increasing the cycle life of the battery device.

[0009] In some embodiments, the battery assembly includes a plurality of battery cells arranged along a first direction, with an elastic member abutting between two adjacent battery cells. The elastic member can transmit forces between two adjacent battery cells, so that the forces on each battery cell in the battery assembly remain essentially constant, and the solid-solid interface can maintain stable and good contact, thereby improving the electrochemical performance of the battery device and increasing the cycle life of the battery device.

[0010] In some embodiments, the elastic member further abuts against at least one end of the battery assembly along the first direction and against the first fixing member. The elastic member can further transmit forces between the fixing member and the battery assembly, improving the overall stress stability of the battery assembly and improving the electrochemical performance of the battery device.

[0011] In some embodiments, the battery cell further includes two opposing second surfaces connected by a first surface, and the area of ​​the first surface is larger than the area of ​​the second surface. The relatively larger area of ​​the first surface allows for greater deformation during the cyclic charging and discharging of the battery device. By placing the first surface against the elastic member, the stress stability of the battery assembly can be improved more effectively.

[0012] In some embodiments, the elastic member is a sheet-like structure. The sheet-like structure facilitates contact between the elastic member and the battery cell at all points, and helps to ensure uniform stress distribution throughout the battery cell.

[0013] In some embodiments, the elastic modulus of the elastic member is from 10 MPa to 500 MPa, and optionally from 50 MPa to 100 MPa. When the elastic modulus of the elastic member is within the above range, the elastic member is in a compressed state in the battery device, and the compressive force is essentially constant; moreover, the elastic member can uniformly transmit force to the battery cells, improve the uniformity of current density at various points on the electrode, and ensure uniform lithium intercalation speed at the negative electrode, thereby reducing the risk of lithium plating and improving the reliability of the battery device.

[0014] In some embodiments, the Shore hardness of the elastic member is between 50A and 90A. When the Shore hardness of the elastic member is within this range, the elastic member can be in a compressed state within the battery device, and the compressive force is substantially constant.

[0015] In some embodiments, the compressive permanent deformation rate of the elastic member is 0 to 30%, optionally 0% to 25%. When the compressive permanent deformation rate of the elastic member is within the above range, the elastic member has the ability to restore its original shape.

[0016] In some embodiments, the average thickness of the elastic member is 0.5 mm to 5 mm, optionally 1 mm to 3 mm. When the average thickness of the elastic member is within the above range, it enables the elastic member to be in a compressed state when located in the battery device, and the compressive force is substantially constant.

[0017] In some implementations, the main material of the elastic member includes one or more of silicone rubber, polyurethane, and butadiene rubber.

[0018] In some embodiments, the fixing assembly further includes two second fixing members disposed opposite each other along a second direction, the two second fixing members being fixedly connected by a first fixing member, and the battery assembly being located between the two second fixing members, wherein the second direction is perpendicular to the first direction. The two second fixing members are fixedly connected by the first fixing member, and the fixing assembly clamps and fixes the battery assembly, applying a preload force based on the battery assembly, thereby improving good contact at the solid-solid interface in the battery assembly.

[0019] Secondly, this application proposes an electrical device including a battery device as described in any embodiment of the first aspect of this application. Attached Figure Description

[0020] 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.

[0021] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0022] Figure 2 is an exploded schematic diagram of a battery pack provided in some embodiments of this application;

[0023] Figure 3 is a schematic diagram of the structure of a battery module provided in some embodiments of this application.

[0024] Figure 4 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0025] Figure 5 is a schematic diagram of the structure of the electrode assembly of a battery cell provided in some embodiments of this application;

[0026] Figure 6 is a schematic diagram of the structure of a battery device provided in some embodiments of this application;

[0027] Figure 7 is a schematic diagram of the structure of a battery device provided in some other embodiments of this application;

[0028] The accompanying drawings may not be drawn to scale.

[0029] The reference numerals in the attached drawings are explained as follows: X, first direction; Y, second direction; 1, vehicle; 2, battery pack; 3, controller; 4, motor; 5, housing; 5a, first housing section; 5b, second housing section; 5c, storage space; 6, battery module; 7, battery device; 30, battery assembly; 31, battery cell; 311, outer casing; 3111, first surface; 3112, second surface; 312, electrode assembly; 3121, positive electrode; 3122, negative electrode; 3123, solid electrolyte layer; 32, elastic member; 40, fixing component; 41, first fixing component; 42, second fixing component. Detailed Implementation

[0030] The following detailed description discloses embodiments of the battery device and power-consuming device of this application. 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 unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0031] 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.

[0032] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0033] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0034] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) 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.

[0035] In this application, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations.

[0036] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0038] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0039] In this application, "multiple" refers to two or more (including two). In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be used again after being discharged by activating the active material in a 0% state of charge manner.

[0040] In this application, the battery cell may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium lithium-ion battery cells, sodium-ion battery cells, magnesium-ion battery cells, lithium metal battery cells, sodium metal batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited to these shapes either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these types either.

[0041] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery device mentioned in this application may include a battery module or a battery pack. A battery device generally includes a housing for encapsulating one or more battery cells. The housing can prevent liquids or other foreign matter from affecting the 0% state of charge or discharge of the battery cells.

[0042] Solid-state and semi-solid-state battery cells both include solid electrolytes, which have higher thermal and chemical stability and can withstand higher temperatures and mechanical stresses, thus improving the reliability of battery cells.

[0043] The main transport between the electrode and the solid electrolyte is through the solid-solid interface. In order for active ions such as lithium ions and sodium ions to be transported smoothly between the electrode and the solid electrolyte, the battery cells are usually fixed in the fixing assembly to form a battery device. Then, a certain pre-tightening force is applied to the battery cells by the fixing assembly to ensure good contact between the electrode and the solid electrolyte interface.

[0044] However, during the cyclic charging and discharging of a battery device, the volume of the battery cells expands or contracts. To mitigate the adverse effects of these volume changes, buffer pads are typically placed between adjacent battery cells. However, these buffer pads exhibit creep relaxation characteristics, causing the pressure on the battery cells to continuously decrease and failing to maintain the stability of the battery cells under stress. Furthermore, the uneven pressure can lead to instability at the solid-solid contact interface of the battery cells, resulting in a rapid decline in the electrochemical performance of the battery cells and a deterioration in cycle life.

[0045] In view of this, the present application proposes a battery device that provides a pre-tightening force to the battery assembly through a fixing component. An elastic member is provided in the battery device, which abuts against the battery cell. During the volume expansion or contraction of the battery cell, the elastic member can be compressed to different degrees in accordance with the volume change of the battery cell. However, the compressive force generated by the elastic member remains basically stable. The elastic member is not prone to creep relaxation, its structure is stable, and the force exerted by the elastic member on the battery cell is basically stable, so that the solid-solid interface can have stable and good contact. This improves the electrochemical performance of the battery device and increases the cycle life of the battery device.

[0046] The battery cells described in this application are applicable to battery devices and electrical devices that use battery devices.

[0047] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of this application do not impose special limitations on the above-mentioned electrical devices.

[0048] For ease of explanation, the following implementation method uses a vehicle as an example of an electrical device.

[0049] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application.

[0050] As shown in Figure 1, a battery pack 2 is installed inside the vehicle 1. The battery pack 2 can be located at the bottom, front, or rear of the vehicle 1. The battery pack 2 can be used to power the vehicle 1; for example, the battery pack 2 can serve as the operating power source for the vehicle 1.

[0051] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery pack 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0052] In some embodiments of this application, the battery pack 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0053] Figure 2 is an exploded view of a battery provided in some embodiments of this application. As shown in Figure 2, the battery pack 2 includes a housing 5 and a battery cell 31 (not shown in Figure 2), with the battery cell 31 housed within the housing 5.

[0054] The housing 5 is used to house the battery cell 31, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the battery cell 31. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.

[0055] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0056] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0057] In battery pack 2, there can be one or more battery cells 31. If there are multiple battery cells 31, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 31 are connected in both series and parallel. Multiple battery cells 31 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 31 is housed in the housing 5. Alternatively, multiple battery cells 31 can first be connected in series, parallel, or in a mixed manner to form battery modules 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed manner to form a whole assembly, which is then housed in the housing 5.

[0058] The battery cell 31 can be the smallest unit that makes up the battery.

[0059] Figure 3 is a schematic diagram of the battery module shown in Figure 2.

[0060] In some embodiments, as shown in Figure 3, there are multiple battery cells 31. These multiple battery cells 31 are first connected in series, parallel, or in a mixed manner to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or in a mixed manner to form a whole, which is housed in a casing.

[0061] Multiple battery cells 31 in battery module 6 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of the multiple battery cells 31 in battery module 6. There can be one or more busbars, and each busbar is used to electrically connect at least two battery cells 31.

[0062] Figure 4 is a schematic diagram of the structure of a battery cell 31 provided in some embodiments of this application; Figure 5 is a schematic diagram of the structure of the electrode assembly 312 of a battery cell 31 provided in some embodiments of this application.

[0063] As shown in Figures 4 and 5, in some embodiments, the battery cell 31 includes an electrode assembly 312 and a housing 311, with the electrode assembly 312 housed within the housing 311.

[0064] The internal cavity formed by the outer shell 311 can be used to accommodate the electrode assembly 312, the electrolyte, and other components. The outer shell 311 can be of various shapes, such as a cylinder or a cuboid. The shape of the outer shell 311 can be determined according to the specific shape of the electrode assembly 312. For example, if the electrode assembly 312 has a cylindrical structure, the outer shell 311 can be a cylindrical structure. If the electrode assembly 312 has a cuboid structure, the outer shell 311 can be a cuboid structure.

[0065] The outer casing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. The embodiments of this application do not impose any special restrictions on this.

[0066] The electrode assembly 312 housed within the housing 311 may be one or more. In this embodiment, the electrode assembly 312 may be a wound structure or a stacked structure, and may be a stacked structure.

[0067] The electrode assembly 312 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 31, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 312 also includes a separator disposed between the positive and negative electrodes, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0068] In some embodiments, the positive electrode can be a positive electrode sheet 3121, which may include 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.

[0069] 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.

[0070] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, silver-surfaced aluminum, or stainless steel can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0071] As an example, when the battery cell 31 in this embodiment is a lithium-ion battery or a lithium metal battery, the positive electrode active material may include one or more of the following materials: phosphates, layered transition metal oxides, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxides and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 31. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode film layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0072] Examples of phosphates may include, but are not limited to, one or more of 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.

[0073] Layered transition metal oxides include those with the general formula Li a Ni b Co c M d O e A f One or more of the compounds and their modified compounds. 0.8≤a≤1.2, 0.3≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes one or more of N, F, S and Cl.

[0074] Examples of layered transition metal oxides may 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 LiNi0.5 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) 0.80 Co 0.15 Al 0.05 One or more of O2 and its modified compounds.

[0075] When the battery cell 31 in the embodiments of this application is a sodium-ion battery or a sodium metal battery, the positive electrode active material may include, but is not limited to, one or more of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0076] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In the given condition, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes H. + Li + Na+ K + and NH4 + One or more of the following, M' is a transition metal cation, optionally one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0077] In the embodiments of this application, the modified compounds of the above-mentioned positive electrode active materials can be doped and / or surface coated to modify the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0078] During the charging and discharging process, the battery cell 31 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 31 at different discharge states. In the examples of positive electrode active materials in this application, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery system, the molar content of Li may change after charge-discharge cycles.

[0079] In the embodiments of this application, the molar content of oxygen (O) in the positive electrode active materials is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0080] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, a positive electrode film layer may or may not be provided on the surface of the foamed metal. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0081] In some embodiments, the positive electrode film layer may optionally include a positive electrode conductive agent. This application does not impose particular limitations on the type of positive electrode conductive agent. As an example, the positive electrode conductive agent includes one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode film layer is ≤5 wt%.

[0082] In some embodiments, the positive electrode film layer may optionally include a positive electrode binder. This application does not impose particular limitations on the type of positive electrode binder. As an example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode film layer is ≤5 wt%.

[0083] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0084] In some embodiments, the battery cell 31 is an ion-type battery such as a lithium-ion battery, and the negative electrode can be a negative electrode sheet 3122. The negative electrode sheet 3122 may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector. The negative electrode film layer includes a negative electrode active material.

[0085] 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.

[0086] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0087] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 31. As an example, the negative electrode active material may include one or more of the following materials: carbon materials (e.g., carbon materials include one or more of artificial graphite, natural graphite, soft carbon, and hard carbon), silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode films may also be used. These negative electrode films may be used alone or in combination of two or more.

[0088] In some embodiments, the negative electrode film layer may optionally include a negative electrode conductive agent. This application does not impose particular limitations on the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode film layer is ≤5 wt%.

[0089] In some embodiments, the negative electrode film layer may optionally include a negative electrode binder. This application does not impose particular limitations on the type of negative electrode binder. As an example, the negative electrode binder may include one or more of the following: styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode film layer is ≤5 wt%.

[0090] In some embodiments, the negative electrode film layer may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of other additives in the negative electrode film layer is ≤2 wt%.

[0091] In some embodiments, the battery cell 31 also includes an electrolyte. During the charging and discharging process of the battery cell 31, active ions repeatedly insert and extract between the positive and negative electrode plates, and the electrolyte plays a role in conducting active ions between the positive and negative electrode plates. The embodiments of this application do not impose any particular limitation on the type of electrolyte, and it can be selected according to actual needs.

[0092] The electrolyte may include a solid electrolyte layer 3123. When the electrolyte is a solid electrolyte layer 3123, it can be used alone or in combination with a liquid electrolyte, i.e., an electrolyte solution. Optionally, the electrolyte is a solid electrolyte.

[0093] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

[0094] Sulfide solid electrolytes include one or more of the following: sulfide crystalline solid electrolytes, sulfide glass, and glass-ceramic solid electrolytes.

[0095] In some embodiments, the sulfide solid electrolyte includes Li 10 GeP2S 12 Li6PS5Cl, Li 10 SnP2S 12 One or more of Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3.

[0096] Oxide solid electrolytes are classified into two categories according to their material structure: crystalline oxide electrolytes and glassy oxide electrolytes (amorphous oxide electrolytes). Crystalline oxide electrolytes include one or more types such as perovskite, NASICON, LISICON, and garnet, while glassy oxide electrolytes include LiPON type electrolytes.

[0097] In some embodiments, the oxide solid electrolyte includes Li 3.3 La 0.56 TiO3, LiTi2(PO4)3, Li 14 Zn(GeO4)4, Li7La3Zr2O 12 Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 2), Li 7-a La3Zr 2-a M a O 12 (M includes one or more of Ta and Nb; 0 < a < 2), Li b La 2 / 3-b TiO3 (0 < b < 2), LiAlO2, Li2ZrO3 and Li4Ti5O 12 One or more of them.

[0098] In some embodiments, the halide solid electrolyte includes one or more of Li3YCl6, Li3ErCl6, Li3YBr6, Li3InBr6, and Li3InCl6.

[0099] Polymer solid electrolytes (SPEs) are primarily composed of a polymer matrix and an electrolyte salt. The electrolyte salt may include lithium salts, specifically one or more of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), and lithium tetrafluoroborate (LiBF4). The electrolyte salt may also include sodium salts, specifically one or more of sodium hexafluorophosphate (NaPF6), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), and sodium tetrafluoroborate (NaBF4).

[0100] In some embodiments, the SPE includes one or more of the following: epoxy compounds, polyester compounds, polyalkoxy compounds, polyolefin compounds, polyacrylonitrile (PAN), and monoionic polymer electrolytes. For example, epoxy compounds include one or more of polyethylene oxide (PEO) and polypropylene oxide (PPO). Polyolefin compounds include one or more of polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC). Polyester compounds include one or more of polycarbonate compounds and polymethyl methacrylate (PMMA). Polycarbonate compounds include one or more of polypropylene carbonate and polytrimethylene carbonate.

[0101] Furthermore, the polymer matrix can be hybridized with inorganic particles, including metal oxide nanoparticles such as MgO, Al2O3, and SiO2, as well as one or more of zeolites and montmorillonite. The addition of inorganic particles can reduce crystallinity, and the interactions between the polymer matrix, lithium salt, and inorganic particles can improve conductivity and ion transference number. Inorganic particles can also adsorb trace impurities such as moisture in the electrolyte and improve mechanical properties.

[0102] As shown in Figure 6, in some embodiments, the battery device 7 includes a battery assembly 30 and a fixing assembly 40. The battery assembly 30 includes an elastic member 32 and a battery cell 31 containing a solid electrolyte. The battery cell 31 includes two first surfaces 3111 that are opposite to each other along a first direction X. The fixing assembly 40 includes two first fixing members 41 that are disposed opposite to each other along the first direction X. The battery assembly 30 is sandwiched between the two first fixing members 41. The elastic member 32 abuts against the battery cell 31 and covers the first surface 3111.

[0103] Each battery cell 31 includes a solid electrolyte, which can be understood as a solid-state battery cell.

[0104] Two first fixing members 41 are arranged opposite each other along the first direction X, clamping all battery components 30 therein, and can give the battery components 30 a pre-tightening force along the first direction X;

[0105] Furthermore, the battery device 7 also includes an elastic member 32, which has elastic deformation capability, such as compressive deformation capability. The elastic member 32 abuts against the battery cell 31 and is in a compressed state, having compressive displacement in the first direction X, and is able to transmit force between the fixing assembly 40 and the battery cell 31. The elastic member 32 can be compressed to different degrees according to the volume change of the battery assembly 30, but the compressive force generated by the elastic member 32 remains basically stable, making the force exerted by the elastic member 32 on the battery cell 31 basically stable. Moreover, the elastic member 32 can cover the first surface 3111, making the force on the first surface 3111 relatively uniform. This allows for stable and good contact between the solid and solid interfaces, thereby improving the electrochemical performance of the battery device 7. In this embodiment, the elastic member 32 covers the first surface 3111, which can be understood as the projection surface of the first surface 3111 along the first direction X being located within the projection surface of the elastic member 32 along the first direction X. The projection area of ​​the elastic member 32 along the first direction X can be substantially equal to the area of ​​the first surface 3111, or the projection area of ​​the elastic member 32 along the first direction X can be greater than the area of ​​the first surface 3111. The first surface 3111 can basically contact the elastic member 32 at all points, making the force on the first surface 3111 uniform and improving the cycle life and reliability of the battery device 7.

[0106] Specifically, during the cyclic charging and discharging process of the battery device 7, the volume of the individual battery cells 31 in the battery assembly 30 undergoes different degrees of volume changes, and the elastic member 32 undergoes different degrees of compression deformation accordingly. The battery device 7 is in different states, for example, the battery device 7 includes a 0% state of charge and a 100% state of charge. In the 0% state of charge, the volume expansion of the battery assembly 30 is relatively small, and the individual battery cells 31 exert a force on the elastic member 32. The elastic member 32 has a first compression displacement along the first direction X, and the elastic member 32 abuts against the individual battery cells 31 with a first compression force F1. When the battery device 7 is 100% charged, the volume expansion of the battery assembly 30 is relatively large. The battery cell 31 exerts a force on the elastic member 32. The elastic member 32 has a second compressive displacement along the first direction X. The elastic member 32 abuts against the battery cell 31 with a second compressive force F2. (F2-F1) / F1 is 0 to 0.1, so that the first compressive force F1 and the second compressive force F2 remain basically constant, and the force on the battery cell 31 remains basically constant. The solid-solid interface can have stable and good contact, thereby improving the electrochemical performance of the battery device 7 and increasing the cycle life of the battery device 7.

[0107] In this embodiment of the application, when the battery cell 31 is charged at a 1C rate to the cutoff upper limit voltage, the battery cell 31 can be considered to be in a 100% state of charge (SOC).

[0108] When the battery cell 31 is discharged at a 1C rate to the cutoff upper limit voltage, the battery cell 31 can be considered to be in a 0% state of charge (SOC).

[0109] In the embodiments of this application, (F2-F1) / F1 is from 0 to 0.1. Indicatively, (F2-F1) / F1 can be 0, 0.0001, 0.0005, 0.001, 0.005, 0.008, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, or a range of any two of the above values. When (F2-F1) / F1 is 0, it indicates that the first compressive force F1 and the second compressive force F2 are the same.

[0110] In this embodiment of the application, the battery assembly 30 includes one or more battery cells 31.

[0111] In some embodiments, the elastic member 32 abuts between two adjacent battery cells 31, and the elastic member 32 is able to transmit force between the two battery cells 31.

[0112] In the embodiments of this application, an elastic member 32 can be provided between any two adjacent battery cells 31; of course, the elastic member 32 can also be provided only between some of the two adjacent battery cells 31.

[0113] For example, the battery assembly 30 includes three battery cells 31 arranged along a first direction X, defined as a first battery cell, a second battery cell, and a third battery cell, respectively. An elastic member 32 is provided between the first and second battery cells, and between the second and third battery cells. In other words, an elastic member 32 is provided between any two adjacent battery assemblies 30, which helps to further improve the stress stability of the battery assembly 30. Alternatively, an elastic member 32 is provided between the first and second battery cells, but not between the second and third battery cells. This approach can simultaneously improve the electrochemical performance and energy density of the battery device 7.

[0114] As shown in Figure 7, in some embodiments, the elastic member 32 is also disposed at at least one end of the battery assembly 30 along the first direction X, which may be both ends; specifically, the elastic member 32 is disposed on at least one side of the plurality of battery cells 31 along the first direction X, which may be both sides, and abuts between the first fixing member 41 and the battery cell 31.

[0115] The elastic member 32 can further transmit forces between the fixed component 40 and the battery component 30, improve the overall stress stability of the battery component 30, and improve the electrochemical performance of the battery device 7.

[0116] In some embodiments, when the outer casing 311 of the battery cell 31 has a cuboid or flat structure, the outer casing 311 includes two first surfaces 3111 and two second surfaces 3112. The two first surfaces 3111 are arranged opposite each other along a first direction X, and the two first surfaces 3111 are connected by the second surfaces 3112. The two second surfaces 3112 are connected by the first surfaces 3111, and the area of ​​the first surfaces 3111 is larger than the area of ​​the second surfaces 3112. Of course, in other embodiments, the two second surfaces 3112 may be arranged opposite each other along a second direction Y. The second surfaces 3112 can be understood as the side surfaces of the battery cell 31.

[0117] The first surface 3111 has a relatively large area, and during the cyclic charging and discharging of the battery device 7, the deformation of the first surface 3111 is relatively greater. By placing the first surface 3111 against the elastic member 32, the stress stability of the battery assembly 30 can be improved more effectively. Of course, in some other embodiments, the elastic member 32 can abut against the second surface 3112.

[0118] In some embodiments, the elastic member 32 can be a sheet-like structure with the above-mentioned characteristics; of course, it can also be other structural forms, such as a funnel-shaped structure with two platforms, the surfaces of the two platforms respectively abutting against the first surface 3111. The sheet-like structure is beneficial for the elastic member 32 and the battery cell 31 to make contact at all points, which is beneficial for the battery cell 31 to be subjected to uniform force at all points.

[0119] Optionally, the elastic modulus of the elastic member 32 is from 10 MPa to 500 MPa, for example, 10 MPa, 50 MPa, 100 MPa, 150 MPa, 200 MPa, 250 MPa, 300 MPa, 350 MPa, 400 MPa, 450 MPa, 500 MPa, or any combination of two of the above values. Optionally, the elastic modulus of the elastic member 32 is from 50 MPa to 100 MPa. Optionally, the elastic modulus of the elastic member is from 50 MPa to 100 MPa. When the elastic modulus of the elastic member 32 is within the above range, the elastic member 32 is in a compressed state in the battery device 7, and the compressive force is substantially constant.

[0120] The elastic member 32 is in contact with the battery cell 31, which can buffer the volume change of the battery cell 31. Moreover, the elastic member 32 can also evenly transmit the external force to all parts of the battery cell 31, so that the force on the battery cell 31 is relatively uniform. Furthermore, since the elastic member 32 has a certain elastic deformation capability, it can be evenly attached to the surface of the battery cell 31, which can alleviate the problem of uneven local force caused by the unevenness of the surface of the battery cell 31, improve the uniformity of current density at all parts of the electrode, and the uniformity of lithium intercalation speed of the negative electrode, reduce the risk of lithium plating, and improve the reliability of the battery device 7.

[0121] Optionally, the Shore hardness of the elastic member 32 is between 50A and 90A, for example, 50A, 55A, 60A, 65A, 70A, 75A, 80A, 85A, 90A, or any combination of two of the above values. When the Shore hardness of the elastic member 32 is within the above range, the elastic member 32 can be in a compressed state in the battery device 7, and the compressive force is substantially constant.

[0122] Optionally, the compressive strength of the elastic member 32 is 0 to 30%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 20%, 25%, 30%, or any combination of two of the above values. Optionally, the compressive strength of the elastic member 32 is 0 to 25%. When the compressive strength of the elastic member 32 is within the above range, the elastic member 32 has the ability to restore its original shape in the battery device 7 and can change accordingly according to the volume change of the battery cell 31.

[0123] Optionally, the average thickness of the elastic member 32 is from 0.5 mm to 5 mm, for example, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or any combination of two of the above values. Optionally, the average thickness of the elastic member 32 is from 1 mm to 3 mm. When the average thickness of the elastic member 32 is within the above range, it is possible to ensure that the elastic member 32 is in a compressed state when located in the battery device 7, and the compressive force is substantially constant.

[0124] The average thickness of the elastic member 32 can be obtained by testing the thickness at multiple locations of the elastic member 32, such as 10 locations, and calculating its average value.

[0125] For example, the elastic member 32 is a sheet structure with an average thickness of 0.5 mm to 5 mm, optionally 1 mm to 3 mm.

[0126] For example, the main material of the elastic member 32 includes rubber-like materials, such as one or more of silicone rubber, polyurethane, and butadiene rubber. In the embodiments of this application, the main material refers to the material with the highest mass proportion in the elastic member 50, such as a material with a mass proportion greater than 80%, or even a material with a mass proportion of 100%.

[0127] It should be noted that rubber-based materials include organic polymers and fillers.

[0128] For example, the organic polymers of silicone rubber include silicone polymers, the organic polymers of polyurethane include polyurethane polymers, and the organic polymers of butadiene rubber include butadiene-1,4-polybutadiene.

[0129] The filler includes one or more of silica, carbon black, and zinc oxide. Fillers can increase the mechanical strength of rubber-like materials, thereby improving their elastic modulus, Shore hardness, and Poisson's ratio. In the embodiments of this application, the elastic modulus, Shore hardness, and Poisson's ratio can be adjusted by changing the mass ratio of the filler in the rubber-like material.

[0130] In some embodiments, the filler content in the rubber material is 20% to 60% by mass, optionally 40% to 60%, for example 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any range of two of the above values.

[0131] As the mass content of filler increases, the elastic modulus of the material also increases, but the compression set also increases.

[0132] Taking silicone rubber as an example,

[0133] When the mass content of silica is 40%, the Shore hardness of silicone rubber is 51A and the compression set is 6%.

[0134] When the mass content of silicon dioxide is 50%, the Shore hardness is 63A and the compression set is 9%.

[0135] When the silica content is 60% by mass, the Shore hardness is 75A and the compression set is 11%.

[0136] For example, the second compression displacement is 5mm to 8mm, such as 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, or any combination of two of the above values. The second compression displacement can be the maximum displacement of the elastic member 32 assembled in the battery device 7, which is related to the expansion and deformation of the battery cell 31. When the second compression displacement is within the above range, the compressive force generated by the elastic member 32 when assembled in the battery device 7 can be kept basically constant, so that the force on the battery assembly 30 can be kept stable, thereby effectively improving the electrochemical performance of the battery device 7.

[0137] For example, the first compression displacement is 5 mm to 8 mm, such as 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, or any combination of two of the above values. The first compression displacement can be the minimum displacement of the elastic member 32 assembled in the battery device 7, which is related to the expansion and deformation of the battery cell 31. When the first compression displacement is within the above range, the compressive force generated by the elastic member 32 when assembled in the battery device 7 can be kept basically constant, so that the force on the battery assembly 30 can be kept stable, thereby effectively improving the electrochemical performance of the battery device 7.

[0138] In this embodiment of the application, the elastic member 32 can be in contact with the first surface 3111; or it can be bonded to the same surface.

[0139] The fixing component 40 is used to fix and clamp the battery assembly 30. In some embodiments, the fixing component 40 may further include two second fixing members 42, which are arranged opposite each other along a second direction Y. The two second fixing members 42 are fixedly connected by a first fixing member 41, and the battery assembly 30 is located between the two second fixing members 42, wherein the second direction Y is perpendicular to the first direction X.

[0140] The first fixing member 41 and the second fixing member 42 can be fixedly connected by welding, bolting or other means; the battery assembly 30 is clamped and fixed by the fixing component 40, and a pre-tightening force is applied to the battery assembly 30 to improve the good contact of the solid-solid interface in the battery assembly 30.

[0141] As a specific embodiment of this application, the battery device 7 includes a battery assembly 30 and a fixing assembly 40. The battery assembly 30 includes an elastic member 32 and a battery cell 31 containing a solid electrolyte. The battery cell 31 includes two first surfaces 3111 that are opposite to each other along the first direction X. The fixing assembly 40 includes two first fixing members 41 that are opposite to each other along the first direction X, and the battery assembly 30 is sandwiched between the two first fixing members 41. The elastic member 32 abuts between two adjacent battery cells 31. The elastic member 32 is also located at both ends of the battery assembly 30 along the first direction X and covers the first surfaces 3111.

[0142] The battery device 7 includes a 0% state of charge and a 100% state of charge. In the 0% state of charge, the elastic member 32 has a first compression displacement along the first direction X, and the elastic member 32 abuts against the battery assembly 30 with a first compression force F1. In the 100% state of charge, the elastic member 32 has a second compression displacement along the first direction X, and the elastic member 32 abuts against the battery assembly 30 with a second compression force F2. The second compression displacement is greater than the first compression displacement, and (F2-F1) / F1 is 0 to 0.1.

[0143] In this application, the elastic modulus of a material has a well-known meaning in the art and can be tested using instruments and methods well-known in the art, such as testing the elastic modulus according to the test method in GB / T 1041-2008 "Determination of compressibility properties of plastics".

[0144] In this application, the thickness of components, etc., are terms known in the art and can be measured using instruments and methods known in the art, such as micrometers.

[0145] In this application, the compressive force of the elastic member 32 is a well-known concept in the art and can be tested using instruments and methods known in the art. For example, in accordance with standard ISO 7500-1, the elastic member 32 is removed by disassembling the battery device 7 and the compressive force is tested by setting the elastic member 32 at a preset compression displacement using a universal testing machine.

[0146] In this application, the Shore hardness of the elastic member 32 can be tested using instruments and methods known in the art, such as according to standard GB / T 531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber Part 1: Shore hardness tester method (Shore hardness).

[0147] In this application, the compressive permanent deformation rate of the elastic member 32 refers to the permanent deformation produced by the member during compression under certain temperature and pressure conditions. It can be used to characterize the elasticity and elastic recovery ability of the frame and can be tested using instruments and methods known in the art.

[0148] For example, rubber materials can be tested according to standard GB / T 7759.1-2015 Determination of compression set of vulcanized rubber or thermoplastic rubber Part 1: Under normal and high temperature conditions;

[0149] Plastic materials can be tested according to the standard GB / T 1041-2008 "Determination of compressive properties of plastics";

[0150] The foam material can be tested according to the standard GB / T 6669-2008 "Determination of compression set of flexible foam polymer materials".

[0151] Example

[0152] The following embodiments describe the contents disclosed in this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of the embodiments of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0153] Example 1

[0154] The battery device includes a battery assembly and a fixing assembly. The battery assembly includes an elastic member and a plurality of battery cells containing solid electrolytes arranged along a first direction. The elastic member is located between two adjacent battery cells and at both ends of the battery assembly along the first direction. The fixing assembly includes two first fixing members arranged opposite to each other along the first direction, with the battery assembly sandwiched between the two first fixing members.

[0155] Examples 2-1 and 2-2

[0156] The battery device was prepared using a method similar to that of Example 1, except that the material of the elastic member was adjusted.

[0157] Examples 3-1 and 3-2

[0158] The battery device was prepared using a method similar to that of Example 1, except that the dimensions of the elastic member, such as its thickness, were adjusted.

[0159] Comparative Example 1

[0160] The battery device was prepared using a method similar to that of Example 1, except that the material of the elastic member was replaced with a cushioning pad.

[0161] Performance testing

[0162] 1. Cycle life of the battery device

[0163] At 25°C, the battery devices prepared in the examples and comparative examples were charged at a 1C rate and discharged at a 1C rate to conduct a full charge and discharge cycle test until the capacity of the battery device decayed to 80% of the initial capacity, and the number of cycles was recorded.

[0164] 2. Lithium plating test of battery device

[0165] At 25°C, the battery devices prepared in the examples and comparative examples were fully charged at 1C and fully discharged at 1C 10 times. Then, the battery devices were fully charged at 1C. The negative electrode was then disassembled and the lithium deposition on the surface of the negative electrode was observed.

[0166] in,

[0167] A lithium deposition area of ​​0 to 1% on the negative electrode surface is considered to indicate no lithium deposition.

[0168] A lithium plating area on the negative electrode surface of greater than 1% and less than or equal to 5% is considered slight lithium plating.

[0169] A lithium plating area on the negative electrode surface of greater than 5% and less than or equal to 40% is considered moderate lithium plating.

[0170] A lithium plating area greater than 40% on the negative electrode surface is considered severe lithium plating.

[0171] Test Results

[0172] The test results are shown in Table 1.

[0173] Table 1

[0174] As can be seen from Table 1,

[0175] Comparative Example 1 uses silicone rubber, in which the filler includes silica. The silica content is less than 20% by mass. During use, it may creep and relax, which may cause pressure fluctuations in the battery cells and changes in the solid-solid contact interface, resulting in rapid degradation of electrochemical performance and deterioration of cycle life.

[0176] The embodiments of this application include an elastic component, which includes silicone rubber. The filler in the silicone rubber includes silicon dioxide, and the mass content of silicon dioxide is 50%. It has a high elastic modulus, which makes the battery component stable under stress during use and allows the solid-solid interface to have stable and good contact, thereby improving the electrochemical performance of the battery device and increasing the cycle life of the battery device.

[0177] When different materials are used for the elastic components, the elastic modulus of the elastic components ranges from 10MPa to 500MPa, and can be selected from 50MPa to 100MPa; the Shore hardness of the elastic components ranges from 50A to 90A, and the compression set rate ranges from 0 to 30%. All of these can ensure the stability of the battery cells under stress and the stable and good contact of the solid-solid interface, thereby improving the electrochemical performance of the battery device and increasing the cycle life of the battery device.

[0178] Furthermore, the aforementioned elastic components can make the force on each part of the battery cell more uniform, which is conducive to the uniform distribution of current density in the electrode, resulting in uniform lithium intercalation in the negative electrode and a lower risk of lithium plating. In the embodiment, the negative electrode has slight lithium plating or even no lithium plating, which can improve the reliability of the battery cell.

[0179] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery device, comprising: A battery assembly includes an elastic member and a battery cell, the battery cell including two first surfaces facing each other along a first direction, the elastic member abutting against the battery cell and covering the first surfaces; The fixing assembly includes two first fixing members disposed opposite each other along a first direction, with the battery assembly sandwiched between the two first fixing members. in, The battery device includes 0% state of charge and 100% state of charge. In the 0% charged state, the elastic member has a first compressive displacement along the first direction, and the elastic member abuts against the battery cell with a first compressive force F1; At the 100% charged state, the elastic member has a second compressive displacement along the first direction, and the elastic member abuts against the battery cell with a second compressive force F2. The second compression displacement is greater than the first compression displacement, and (F2-F1) / F1 is between 0 and 0.

1.

2. The battery device according to claim 1, wherein, The battery assembly includes a plurality of battery cells arranged along a first direction, and the elastic member abuts between two adjacent battery cells.

3. The battery device according to claim 1 or 2, wherein, The elastic member also abuts against at least one end of the battery assembly along the first direction and against the first fixing member.

4. The battery device according to any one of claims 1 to 3, wherein, The battery cell also includes two second surfaces that are opposite each other, which are connected by the first surface, and the area of ​​the first surface is larger than the area of ​​the second surface.

5. The battery device according to any one of claims 1 to 4, wherein, The elastic member has a sheet-like structure.

6. The battery device according to any one of claims 1 to 5, wherein, The elastic modulus of the elastic member is from 10 MPa to 500 MPa.

7. The battery device according to any one of claims 1 to 6, wherein, The Shore hardness of the elastic member is 50A to 90A.

8. The battery device according to any one of claims 1 to 7, wherein, The compressive permanent deformation rate of the elastic member is 0 to 30%.

9. The battery device according to claim 8, wherein, The average thickness of the elastic member is 0.5 mm to 5 mm.

10. The battery device according to any one of claims 1 to 9, wherein, The main material of the elastic component includes one or more of silicone rubber, polyurethane, and butadiene rubber.

11. The battery device according to any one of claims 1 to 10, wherein, The fixing assembly further includes two second fixing members disposed opposite each other along a second direction. The two second fixing members are fixedly connected by the first fixing member, and the battery assembly is located between the two second fixing members, wherein the second direction is perpendicular to the first direction.

12. An electrical device comprising a battery device as claimed in any one of claims 1 to 11.

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