Battery cell, battery device and electric device

Abstract

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises a first buffer assembly and at least one electrode assembly, each electrode assembly comprises a main body part and a tab part connected to at least one side of the main body part along a first direction, the main body part comprises a positive electrode part containing a positive electrode active material, a negative electrode part containing a negative electrode active material and a solid electrolyte layer, the positive electrode part, the solid electrolyte layer and the negative electrode part are stacked along the thickness direction of the battery monomer, and the first direction is vertical to the thickness direction; the first buffer assembly is arranged on at least one side of the at least one electrode assembly in the thickness direction, and the projection of the main body part in the thickness direction is located in the projection of the first buffer assembly in the thickness direction. The use reliability of the battery monomer disclosed by the invention can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a battery cell, a battery device and a power consumption device. BACKGROUND

[0002] Battery cells have characteristics such as high capacity and long service life, and are widely used in electronic devices such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools, etc. Due to the great progress of batteries, higher requirements are put forward for the performance of batteries.

[0003] However, the use reliability of the battery cell is still poor. SUMMARY

[0004] The present application provides a battery cell, a battery device and a power consumption device, and the use reliability of the battery cell described in the present application can be improved.

[0005] In a first aspect, the embodiments of the present application provide a battery cell, the battery cell comprising a first buffer assembly and at least one electrode assembly, each electrode assembly comprising a main body part and a tab part connected to at least one side of the main body part along a first direction, the main body part comprising a positive electrode part containing a positive electrode active material, a negative electrode part containing a negative electrode active material and a solid electrolyte layer, the positive electrode part, the solid electrolyte layer and the negative electrode part being stacked along a thickness direction of the battery cell, the first direction being perpendicular to the thickness direction; the first buffer assembly is arranged on at least one side of the at least one electrode assembly along the thickness direction, and the projection of the main body part along the thickness direction is located within the projection of the first buffer assembly along the thickness direction.

[0006] Thus, in the embodiments of the present application, the first buffer assembly can effectively buffer and protect the battery cell, reduce the risk of damage to the electrode assembly inside the battery cell, reduce the risk of tab breakage and powder falling off, reduce the risk of positive and negative electrode contact short circuit, and improve the structural stability and use reliability of the battery cell.

[0007] In some embodiments, the first buffer assembly is arranged on both sides of the at least one electrode assembly along the thickness direction. Thus, the structural stability and use reliability of the battery cell can be further improved in the embodiments of the present application.

[0008] In some embodiments, the first buffer assembly extends beyond the main body part along a second direction, and the second direction, the first direction and the thickness direction are perpendicular to each other. The first buffer assembly can effectively buffer and protect the electrode assembly, and improve the structural stability of the battery cell.

[0009] In some embodiments, the first buffer assembly also covers a portion of the tab portion close to the body portion. The first buffer assembly covering the portion of the tab portion can effectively protect the connection area between the tab portion and the body portion, and provide space for assembling the tab portion with external components.

[0010] In some embodiments, the portion of the tab portion close to the body portion has a dimension along the first direction of L1, and the tab portion has a dimension along the first direction of L2, L1 / L2 is greater than 0 and less than or equal to 0.5. The first buffer assembly covering the portion of the tab portion can effectively protect the connection area between the tab portion and the body portion, and provide space for assembling the tab portion with external components.

[0011] In some embodiments, the first buffer assembly has a dimension along the thickness direction of H1, and the electrode assembly has a dimension along the thickness direction of H2, H1 / H2 is greater than 0 and less than or equal to 0.3. When the thickness of the first buffer assembly is within the above range, the first buffer assembly can effectively protect the battery cell, and at the same time, the space occupied by the first buffer assembly is not too large, so that the appropriate energy density can be achieved.

[0012] In some embodiments, the first buffer assembly has a layered structure. The layered structure covering the electrode assembly can more effectively protect the battery cell.

[0013] In some embodiments, the layered structure comprises one or more hole structures. The hole structures can make the layered structure lighter, which is beneficial to improve the weight energy density of the battery cell.

[0014] In some embodiments, the first buffer assembly is attached to at least one side of the electrode assembly along the thickness direction. The first buffer assembly has a strong bonding force with the electrode assembly, and is not prone to position movement. During the charging and discharging process of the battery cell, the first buffer assembly can effectively protect the battery cell.

[0015] In some embodiments, the peeling strength between the first buffer assembly and the electrode assembly is greater than 0 N / m and less than or equal to 30 N / m. When the peeling strength is within the above range, the first buffer assembly has a strong bonding force with the surface of the electrode assembly, and is not prone to falling off from the electrode assembly.

[0016] In some embodiments, the first buffer assembly has an elastic modulus of 5 MPa to 200 MPa. When the elastic modulus of the first buffer assembly is within the above range, the first buffer assembly has excellent elastic deformation ability, and can effectively buffer the stress problems caused by internal and external actions of the battery cell.

[0017] In some embodiments, the first buffer assembly has a Poisson's ratio of 0.2 to 0.35. When the Poisson's ratio of the first buffer assembly is within the above range, the first buffer assembly has excellent elastic deformation ability, and can effectively buffer the stress problems caused by internal and external actions of the battery cell.

[0018] In some embodiments, the first buffer assembly comprises one or more of a polyolefin-based polymer, a polysiloxane-based polymer, a polyimide, a polyurethane, a polyethylene terephthalate, and a polystyrene butadiene copolymer.

[0019] In some embodiments, the polyolefin-based polymer comprises one or more of polypropylene, cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and ethylene propylene terpolymer.

[0020] In some embodiments, the polysiloxane-based polymer comprises one or more of polymethylvinylsiloxane, polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0021] In some embodiments, a projection of the negative electrode portion along the thickness direction is located within a projection of the solid-state electrolyte layer along the thickness direction, and the projection of the solid-state electrolyte layer along the thickness direction is located within a projection of the first buffer assembly along the thickness direction. The first buffer assembly can effectively buffer and protect the main body portion structure of the electrode assembly.

[0022] In some embodiments, the battery monomer further comprises a shell, the shell accommodating the electrode assembly and the first buffer assembly.

[0023] In a second aspect, the embodiments of the present application further provide a battery device comprising the battery monomer of any of the embodiments of the first aspect.

[0024] In some embodiments, the battery device further comprises a second buffer assembly, the second buffer assembly being arranged on at least one side of the at least one battery monomer along the thickness direction, and a projection of the main body portion of the battery monomer along the thickness direction being located within a projection of the second buffer assembly along the thickness direction.

[0025] Thus, in the embodiments of the present application, the second buffer assembly can effectively buffer and protect the battery monomer, reduce the risk of damage to the electrode assembly in the battery monomer, reduce the risk of breakage and powdering of the electrode tab, reduce the risk of positive and negative electrode contact short circuit, and improve the structural stability and use reliability of the battery monomer.

[0026] In a third aspect, the embodiments of the present application further provide a battery device, which comprises a second buffer assembly and at least one battery cell. Each battery cell comprises at least one electrode assembly, and each electrode assembly comprises a main body part and a tab part connected to at least one side of the main body part along a first direction. The main body part comprises a positive electrode part containing a positive electrode active material, a negative electrode part containing a negative electrode active material, and a solid electrolyte layer. The positive electrode part, the solid electrolyte layer, and the negative electrode part are stacked along a thickness direction of the battery cell, and the first direction is perpendicular to the thickness direction. The second buffer assembly is arranged on at least one side of the at least one battery cell along the thickness direction, and a projection of the main body part along the thickness direction is located within a projection of the second buffer assembly along the thickness direction.

[0027] Therefore, in the embodiments of the present application, the second buffer assembly can effectively buffer and protect the battery cell, reduce the risk of damage to the electrode assembly in the battery cell, reduce the risk of breakage and powdering of the tab, reduce the risk of positive and negative electrode contact short circuit, and improve the structural stability and use reliability of the battery cell.

[0028] In some embodiments, the second buffer assembly is arranged on both sides of the at least one battery cell along the thickness direction. Therefore, in the embodiments of the present application, the second buffer assembly can further improve the structural stability and use reliability of the battery cell.

[0029] In some embodiments, the battery cell is a plurality of battery cells, and the second buffer assembly is arranged between adjacent two battery cells. Therefore, in the embodiments of the present application, the second buffer assembly can further improve the structural stability and use reliability of the battery cell.

[0030] In some embodiments, the second buffer assembly extends beyond the main body part along a second direction, and the second direction, the first direction, and the thickness direction are perpendicular to each other. The second buffer assembly can effectively buffer and protect the electrode assembly, and improve the structural stability of the battery cell.

[0031] In some embodiments, a projection of the second buffer assembly along the thickness direction is located within a projection of the battery cell along the thickness direction. The above arrangement can reduce the space occupation of the second buffer assembly, and is beneficial to improving the energy density of the battery device.

[0032] In some embodiments, the second buffer assembly further covers a part of the tab part close to the main body part. The part of the tab part covered by the first buffer assembly can effectively buffer and protect the connection area of the tab part and the main body part, and provide space for assembling the tab part with external components.

[0033] In some embodiments, the second buffer assembly has a thickness of H3, and the battery cell has a thickness of H4, and H3 / H4 is greater than 0 and less than or equal to 0.35. The first buffer assembly covers the portion of the tab part, and can effectively protect the connection area between the tab part and the main body part, and provide space for assembling the tab part and the external component.

[0034] In some embodiments, the second buffer assembly has a layered structure. The layered structure covers the electrode assembly, and can effectively protect the battery cell.

[0035] In some embodiments, the layered structure includes one or more hole structures. The hole structures are configured to make the layered structure lighter, which is beneficial to improve the weight energy density of the battery cell.

[0036] In some embodiments, the second buffer assembly is attached to at least one side of the battery cell in the thickness direction. The second buffer assembly has a strong bonding force with the battery cell, and is not prone to position movement. During the charging and discharging process of the battery cell, the second buffer assembly can effectively protect the battery cell.

[0037] In some embodiments, the peeling strength between the second buffer assembly and the shell of the battery cell is greater than 0 N / m and less than or equal to 30 N / m. When the peeling strength is in the above range, the second buffer assembly has a strong bonding force with the surface of the battery cell, and is not prone to falling off the electrode assembly.

[0038] In some embodiments, the second buffer assembly has an elastic modulus of 5 MPa to 200 MPa. When the elastic modulus of the second buffer assembly is in the above range, the second buffer assembly has excellent elastic deformation capability, and can effectively buffer the stress problems caused by internal and external effects of the battery cell.

[0039] In some embodiments, the second buffer assembly has a Poisson's ratio of 0.2 to 0.35. When the Poisson's ratio of the second buffer assembly is in the above range, the second buffer assembly has excellent elastic deformation capability, and can effectively buffer the stress problems caused by internal and external effects of the battery cell.

[0040] In some embodiments, the second buffer assembly includes one or more of a polyolefin-based polymer, an organosiloxane-based polymer, a polyimide, a polyurethane, a polyethylene terephthalate, and a polystyrene butadiene copolymer.

[0041] In some embodiments, the polyolefin-based polymer includes one or more of polypropylene, cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and terpolymer.

[0042] In some embodiments, the organosiloxane-based polymer comprises one or more of polymethylvinylsiloxane (PMVS), polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0043] In a fourth aspect, the embodiments of the present application further provide a battery device, which comprises the battery device according to any one of the embodiments of the second aspect or the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of the drawings.

[0045] Figure 1 is a schematic diagram of an embodiment of a vehicle of the present application.

[0046] Figure 2 is a schematic diagram of an embodiment of a battery pack of the present application.

[0047] Figure 3 is a schematic diagram of an embodiment of a battery module of the present application.

[0048] Figure 4 is a schematic diagram of an embodiment of a battery module and a second buffer assembly of the present application.

[0049] Figure 5 is a schematic diagram of an embodiment of a battery pack and a second buffer assembly of the present application.

[0050] Figure 6 is a schematic diagram of a structure of a battery cell of the present application.

[0051] Figure 7 is a schematic diagram of an embodiment of an electrode assembly and a first buffer assembly in a battery cell of the present application.

[0052] Figure 8 is a schematic diagram of another embodiment of an electrode assembly and a first buffer assembly in a battery cell of the present application.

[0053] Figure 9 is a schematic diagram of still another embodiment of an electrode assembly and a first buffer assembly in a battery cell of the present application.

[0054] Figure 10 is a schematic diagram of yet another embodiment of an electrode assembly and a first buffer assembly in a battery cell of the present application.

[0055] The drawings are not necessarily drawn according to the actual proportions.

[0056] Reference signs are explained as follows.

[0057] X, thickness direction; Y, first direction; Z, second direction;

[0058] 1, electric device; 2, battery pack; 3, controller; 4, motor; 5, case; 5a, first case portion;

[0059] 5b, second case portion; 5c, accommodation space; 6, battery module;

[0060] 7, battery cell;

[0061] 10, electrode assembly; 11, tab portion; 111, positive electrode tab; 112, negative electrode tab;

[0062] 12, main body portion;

[0063] 13, positive electrode portion; 14, negative electrode portion; 15, solid electrolyte layer;

[0064] 20, housing;

[0065] 30, first cushioning assembly;

[0066] 8, second cushioning assembly. DETAILED DESCRIPTION

[0067] Hereinafter, embodiments of the battery cell, the battery device, and the electric device of the present application are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed description is omitted. For example, there will be cases where detailed description of matters that are already well known, repeated description of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided so that those skilled in the art can fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0068] The ranges disclosed herein are intended to be "open" ranges, i.e., the upper and lower limits of the range are not included. The ranges are also intended to include any and all sub-ranges of the range, i.e., all combinations of any two of the range limits, unless otherwise indicated. For example, a range of "1 to 10" is intended to include any number from 1 to 10, including the numbers 1 and 10. Any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed

[0069] All embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, if not specifically stated otherwise.

[0070] All technical features and optional technical features of the present application can be combined with each other to form new technical solutions, if not specifically stated otherwise.

[0071] All steps of the present application can be performed in sequence or randomly, preferably in sequence, if not specifically stated otherwise. For example, a method comprising steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, it is mentioned that the method can further comprise step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0072] "Multiple" appearing in the present application means more than two (including two).

[0073] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to these. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, cuboid / square battery cells, and pouch battery cells. Optionally, the battery cell in this application may be a pouch battery cell.

[0074] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0075] In some implementations, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0076] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0077] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0078] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0079] When the electrode assembly of a battery cell includes a solid electrolyte layer, the electrode assembly is brittle and prone to damage. Furthermore, the battery cell expands in volume during charging and discharging, generating internal stress; the battery cell may also be subjected to external forces. Both internal stress and external forces can damage the electrode assembly, resulting in poor structural stability and reliability of the battery cell.

[0080] The embodiments of this application buffer the force by setting a buffer component in the battery device and / or battery cell, so that the electrode component is not easily damaged, thereby improving the structural stability of the battery cell and improving the cycle life of the battery cell.

[0081] The battery cells described in this application are applicable to battery devices and electrical devices that use battery devices.

[0082] 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.

[0083] For ease of explanation, the following implementation method uses a vehicle as an example of an electrical device.

[0084] Figure 1 A schematic diagram of the vehicle structure provided for some embodiments of this application.

[0085] like Figure 1 As shown, 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.

[0086] 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.

[0087] 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.

[0088] Figure 2 This is an exploded view of a battery pack provided for some embodiments of this application. For example... Figure 2 As shown, the battery pack 2 includes a housing 5 and individual battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0089] The housing 5 is used to house individual battery cells, 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 individual battery cells. The second housing portion 5b may be a hollow structure with one open end, 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 open side, 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 have various shapes, such as cylinders, cuboids, etc.

[0090] 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.

[0091] 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.

[0092] In battery pack 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed in housing 5. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed in housing 5.

[0093] A single battery cell can be the smallest unit that makes up a battery device.

[0094] Figure 3 for Figure 2 The diagram shows the structure of battery module 6.

[0095] In some implementations, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0096] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0097] When the battery device includes multiple battery cells 7, the multiple battery cells 7 can be stacked and assembled into a battery pack along the thickness direction X of the battery cells 7; or the multiple battery cells 7 can be grouped, and each group of battery cells 7 can be stacked and assembled into a battery module 6 along the thickness direction X, and then the battery modules 6 can be assembled into a battery pack.

[0098] In some embodiments, the battery device further includes a buffer assembly, such as a second buffer assembly 8 disposed on at least one side of at least one battery cell 7 along the thickness direction X.

[0099] like Figure 3 and Figure 4 As shown, when the battery device is a battery module 6, the battery module 6 includes at least one battery cell 7 stacked along the thickness direction X. The at least one battery cell 7 is considered as a whole, and the second buffer assembly 8 is disposed on at least one side of the at least one battery cell 7. For example, the second buffer assembly 8 is disposed on at least one side of the at least one battery cell 7 along the thickness direction X, and the projection of the main body portion 12 of the battery cell 7 along the thickness direction X is located within the projection of the second buffer assembly 8 along the thickness direction X. Optionally, the second buffer assembly 8 is disposed on both sides of the at least one battery cell 7. For example, when the at least one battery cell 7 is a plurality of battery cells 7, the plurality of battery cells 7 are considered as a whole, and the second buffer assembly 8 is disposed on both sides of the plurality of battery cells 7.

[0100] The second buffer component 8 can effectively buffer and protect the large surface of the battery cell 7. In this embodiment, the large surface of the battery cell 7 refers to the surface with a relatively large area. For example, the electrode assembly 10 has a cuboid structure and can include four side surfaces and two main surfaces. The area of ​​the main surfaces is larger than that of the side surfaces. The main surfaces are perpendicular to the thickness direction X, and the stress on the main surfaces is more significant. By setting the second buffer component 8 opposite to the large surface, the large surface can be effectively buffered and protected, thereby effectively buffering and protecting the battery cell 7, reducing the risk of damage to the electrode assembly 10 inside the battery cell 7, reducing the risk of electrode breakage and powder shedding, reducing the risk of short circuit between the positive and negative electrodes, reducing problems such as high self-discharge and capacity loss of the battery cell 7, improving the structural stability and reliability of the battery cell 7, and thus improving the structural stability of the battery device.

[0101] Furthermore, a second buffer assembly 8 can be provided between two adjacent battery cells 7, which can further enhance the buffer protection of the battery cells 7.

[0102] In some embodiments, the second buffer assembly 8 extends beyond the electrode assembly 10 along the second direction Z; specifically, the second buffer assembly 8 extends beyond the main body 12 along the second direction Z. The second buffer assembly 8 can effectively buffer and protect the electrode assembly 10 in the battery cell 7, improving the structural stability of the battery pack. Of course, the dimension of the second buffer assembly 8 along the second direction Z can also be the same as the dimension of the electrode assembly 10 along the second direction Z, or their projections in the thickness direction X can coincide.

[0103] Since the electrode assembly 10 in the battery cell 7 is at high risk of damage, the second buffer assembly 8 effectively buffers and protects the electrode assembly 10, thereby improving the structural stability of the battery cell 7. Furthermore, by ensuring that the projection of the second buffer assembly 8 along the thickness direction X lies within the projection of the battery cell 7 along the thickness direction X, the space occupancy rate of the second buffer assembly 8 is reduced, increasing the space occupancy rate of the battery cell 7 and thus improving the volumetric energy density of the battery module 6. For example, the dimension of the second buffer assembly 8 along the second direction Z can be the same as the dimension of the battery cell 7 along the second direction Z, or the dimension of the second buffer assembly 8 along the second direction Z can be smaller than the dimension of the battery cell 7 along the second direction Z.

[0104] In some embodiments, the tab 11 of the battery cell 7 is connected to at least one side of the main body 12 along the first direction Y, wherein the first direction Y, the second direction Z, and the thickness direction X are perpendicular to each other; the second buffer assembly 8 also extends to the connection between the main body 12 and the tab 11 of the battery cell 7, providing effective buffer protection at the connection and reducing the risk of the tab 11 breaking at the connection.

[0105] Furthermore, the second buffer assembly 8 also covers the portion of the tab 11 in the battery cell 7 that is close to the main body 12; even further, the portion of the tab 11 close to the main body 12 has a dimension L1 along the first direction Y, and the tab 11 has a dimension L2 along the first direction Y, where L1 / L2 is greater than 0 and less than or equal to 0.5. The second buffer assembly 8 covers the L1 portion, which can effectively buffer and protect the tab 11, and also provides space for the tab 11 to be assembled with external components.

[0106] In some embodiments, the second buffer assembly 8 has a dimension of H3 along the thickness direction X, and the battery cell 7 has a dimension of H4 along the thickness direction X. H3 / H4 is greater than 0 and less than or equal to 0.35, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, or a range consisting of any two of the above values. When the thickness of the second buffer assembly 8 is within the above range, it can provide effective buffering protection without occupying excessive space, thereby achieving a suitable energy density. Figure 4In the diagram, H3 represents the dimension of the second buffer assembly 8 along the thickness direction X, i.e., the thickness of the second buffer assembly 8. H4 represents the dimension of the battery cell 7 along the thickness direction X, i.e., the thickness of the battery cell 7.

[0107] In some embodiments, the second buffer component 8 can be a layered structure, such as a single-layer structure or a multi-layer composite structure. Of course, the second buffer component 8 can also be other structural types, such as a frame structure. The layered structure covers the large surface area of ​​the battery cell 7, providing more effective protection and buffering for the battery cell 7.

[0108] Layered structures can incorporate one or more pores. These pores may penetrate the layered structure along its thickness direction (X) or not. The inclusion of pores allows the layered structure to take on a mesh-like or other form. The inclusion of pores makes the layered structure lighter, which is beneficial for increasing the gravimetric energy density of the battery device. Of course, layered structures can also be solid structures, meaning they generally do not include macroscopic pores; however, due to the inherent properties of the material, layered structures can include micropores and other similar structures.

[0109] In some embodiments, the second buffer component 8 may be disposed on the surface of the battery cell 7, and the second buffer component 8 and the outer casing 20 of the battery cell 7 are in contact, but there may be no bonding force between them.

[0110] In other embodiments, the second buffer component 8 can be adhered to the surface of the battery cell 7. The second buffer component 8 has a strong bond with the battery cell 7 and is not prone to positional movement. During the charging and discharging process of the battery device, it can effectively play a buffering and protective role.

[0111] Optionally, the peel strength between the second buffer component 8 and the outer casing 20 is greater than 0 N / m and less than or equal to 30 N / m, for example, 1 N / m, 5 N / m, 8 N / m, 10 N / m, 12 N / m, 13 N / m, 15 N / m, 16 N / m, 18 N / m, 20 N / m, 22 N / m, 25 N / m, 28 N / m, 30 N / m, or any two of the above values. When the peel strength is within the above range, the second buffer component 8 has a stronger bond with the surface of the battery cell 7 and is not easy to detach from the battery cell 7.

[0112] In the embodiments of this application, the peel strength between the second buffer component 8 and the outer shell 20 has a meaning known in the art and can be tested using equipment and methods known in the art, such as the test method for peel strength of adhesive tape in GB / T 2792-2014.

[0113] In some embodiments, the elastic modulus of the second buffer component 8 is from 5 MPa to 200 MPa, for example, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, or any combination of two of the above values. When the elastic modulus of the second buffer component 8 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0114] In this application, the elastic modulus of a material has a meaning known in the art and can be tested using instruments and methods known in the art, such as according to GB / T 14694-1993, the method for determining the compressive elastic modulus of plastics.

[0115] In some embodiments, the Poisson's ratio of the second buffer component 8 is between 0.2 and 0.35, for example, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, or any combination of two of the above values. When the Poisson's ratio of the second buffer component 8 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0116] In this application, the Poisson's ratio of the material is a meaning known in the art and can be tested using instruments and methods known in the art, such as in accordance with GB / T1040.1-2018 Determination of tensile properties of plastics Part 1: General (ISO 527-1:2012).

[0117] In some embodiments, the second buffer component 8 includes one or more of polyolefin polymers, organosiloxane polymers, polyimides, polyurethanes, polyethylene terephthalate, and polystyrene-butadiene copolymers.

[0118] For example, the polyolefin polymer includes one or more of cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and ethylene propylene diene monomer (EPDM) copolymers.

[0119] For example, organosiloxane polymers include one or more of polymethylvinylsiloxane (PMVS), polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0120] The aforementioned materials can exist in the form of rubber pads, such as cis-1,4-polyisoprene rubber.

[0121] like Figure 5 As shown, when the battery device is a battery pack, the battery pack includes multiple battery modules 6, which can be stacked along the thickness direction X. The second buffer component 8 can be disposed on at least one side of the multiple battery modules 6 along the thickness direction X, thereby effectively buffering and protecting the individual battery cells 7 in the battery modules 6. Optionally, the second buffer component 8 can also be disposed on both sides of the multiple battery modules 6 along the thickness direction X.

[0122] Furthermore, a second buffer component 8 can be provided between two adjacent battery modules 6 to further enhance the buffer protection of the battery module 6.

[0123] In some embodiments, the second buffer assembly 8 has a dimension of H3 along the thickness direction X, and the battery cell 7 has a dimension of H4 along the thickness direction X. H3 / H4 is greater than 0 and less than or equal to 0.35, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, or a range consisting of any two of the above values. When the thickness of the second buffer assembly 8 is within the above range, it can provide effective buffering protection without occupying excessive space, thereby achieving a suitable energy density.

[0124] In some embodiments, the second buffer component 8 can be a layered structure, such as a single-layer structure or a multi-layer composite structure. Of course, the second buffer component 8 can also be other structural types, such as a frame structure. The layered structure covering the surface of the battery module 6 can provide more effective protection and buffering for the individual battery cells 7.

[0125] Layered structures can incorporate one or more pores. These pores may penetrate the layered structure along its thickness direction (X) or not. The inclusion of pores allows the layered structure to take on a mesh-like or other form. The inclusion of pores makes the layered structure lighter, which is beneficial for increasing the gravimetric energy density of the battery device. Of course, layered structures can also be solid structures, meaning they generally do not include macroscopic pores; however, due to the inherent properties of the material, layered structures can include micropores and other similar structures.

[0126] In some embodiments, the second buffer component 8 may be disposed on the surface of the battery module 6, and the second buffer component 8 and the housing 20 of the battery module 6 may be in contact, but there may be no bonding force between them.

[0127] In other embodiments, the second buffer component 8 can be adhered to the surface of the battery module 6. The second buffer component 8 has a strong bond with the battery module 6 and is not prone to positional movement. During the charging and discharging process of the battery pack, it can effectively play a buffering and protective role.

[0128] Optionally, the peel strength between the second buffer component 8 and the outer casing 20 is greater than 0 N / m and less than or equal to 30 N / m, for example, 1 N / m, 5 N / m, 8 N / m, 10 N / m, 12 N / m, 13 N / m, 15 N / m, 16 N / m, 18 N / m, 20 N / m, 22 N / m, 25 N / m, 28 N / m, 30 N / m, or any two of the above values. When the peel strength is within the above range, the bonding force between the second buffer component 8 and the surface of the battery module 6 is stronger, and it is not easy for the second buffer component 8 to fall off.

[0129] In some embodiments, the elastic modulus of the second buffer component 8 is from 5 MPa to 200 MPa, for example, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, or any combination of two of the above values. When the elastic modulus of the second buffer component 8 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0130] In some embodiments, the Poisson's ratio of the second buffer component 8 is between 0.2 and 0.35, for example, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, or any combination of two of the above values. When the Poisson's ratio of the second buffer component 8 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0131] like Figure 6 As shown, in some embodiments, the battery cell 7 includes an electrode assembly 10 and a housing 20, with the electrode assembly 10 housed within the housing 20.

[0132] The outer casing 20 can be of various shapes, such as a cylinder or a cuboid. The shape of the outer casing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cylindrical structure, the outer casing 20 can be a cylindrical structure. If the electrode assembly 10 is a cuboid structure, the outer casing 20 can be a cuboid structure. Optionally, the outer casing 20 can be a cuboid structure.

[0133] The outer casing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not impose any special limitations on this. Optionally, the inner wall of the outer casing 20 may also include an insulating layer, which can separate the outer casing 20 from the electrode assembly 10, reducing the risk of short circuit. The material of the insulating layer can be selected from materials commonly used in the art, and no special limitations are imposed here.

[0134] The electrode assembly 10 housed within the housing 20 may be one or more.

[0135] like Figure 7 As shown, from the external shape of the electrode assembly 10, the electrode assembly 10 includes a tab portion 11 and a main body portion 12. The tab portion 11 includes a positive electrode tab 111 and a negative electrode tab 112, with opposite polarities. The positive electrode tab 111 and the negative electrode tab 112 extend beyond the main body portion 12. The positive electrode tab 111 is the portion of the positive electrode sheet without a positive active material layer, and the portion of the positive electrode sheet coated with a positive active material layer is the positive electrode portion 13. The negative electrode tab 112 is the portion of the negative electrode sheet without a negative active material layer, and the portion of the negative electrode sheet coated with a negative active material layer is the negative electrode portion 14. The negative electrode tabs 112 and 112 are used to draw out the current from the main body portion 12.

[0136] The positive electrode tab 111 and the negative electrode tab 112 can be drawn from the same end of the main body 12, or the positive electrode tab 111 and the negative electrode tab 112 can be drawn from opposite ends of the main body 12 respectively.

[0137] The electrode assembly 10 includes a positive electrode, a negative electrode, and a solid electrolyte layer 15. During the charging and discharging process of the battery cell 7, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive and negative electrode.

[0138] The positive electrode portion 13 includes a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector.

[0139] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction X, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0140] As an example, the positive 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-treated 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.).

[0141] As an example, when the battery cell 7 in this embodiment is a lithium-ion battery, the positive electrode active material may include one or more of the following materials: phosphate, layered transition metal oxide, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxide and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 7. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0142] 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.

[0143] 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.

[0144] 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 LiNi 0.5Co 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.

[0145] When the battery cell 7 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.

[0146] 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.

[0147] 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.

[0148] During the charging and discharging process, the battery cell 7 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 7 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.

[0149] 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.

[0150] 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, the surface of the foamed metal may or may not have a positive electrode active material layer. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0151] In some embodiments, the positive electrode active material 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 active material layer is ≤5 wt%.

[0152] In some embodiments, the positive electrode active material 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 active material layer is ≤5 wt%.

[0153] The positive electrode active material layer is typically formed by coating a positive electrode slurry onto the 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.

[0154] In some embodiments, the battery cell 7 is an ion-type battery such as a lithium-ion battery, and the negative electrode portion 14 may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material.

[0155] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction X, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0156] As an example, the negative current collector can be made of metal foil, foamed metal, or a composite current collector. For example, as a metal foil, silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc., can be used. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. A composite current collector may include a polymer material base layer and a metal layer. A composite current collector 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.).

[0157] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 7. 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 negative electrode active material layers in batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0158] In some embodiments, the negative electrode active material 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 active material layer is ≤5 wt%.

[0159] In some embodiments, the negative electrode active material 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 active material layer is ≤5 wt%.

[0160] In some embodiments, the negative electrode active material 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 active material layer is ≤2 wt%.

[0161] In some embodiments, the battery cell 7 also includes an electrolyte. During the charging and discharging process of the battery cell 7, active ions repeatedly insert and extract between the positive and negative electrode plates, and the electrolyte acts as a conductor for these 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.

[0162] The electrolyte may include a solid electrolyte, for example, a solid electrolyte disposed in the form of a film between the positive electrode and the negative electrode. For example, the positive electrode, the solid electrolyte layer 15 and the negative electrode are stacked, and the solid electrolyte layer 15 may be coated on the surface of the positive electrode active material layer in the positive electrode, or coated on the surface of the negative electrode active material layer in the negative electrode.

[0163] Electrolytes can include solid electrolytes and liquid electrolytes. Liquid electrolytes can be made of materials known in the art.

[0164] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

[0165] Sulfide solid electrolytes include one or more of the following: sulfide crystalline solid electrolytes, sulfide glass, and glass-ceramic solid electrolytes.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] In some embodiments, the halide solid electrolyte includes one or more of Li3YCl6, Li3ErCl6, Li3YBr6, Li3InBr6, and Li3InCl6.

[0170] 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).

[0171] 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.

[0172] 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.

[0173] When the battery cell 7 in the embodiments of this application is a lithium-ion battery, as an example, the electrolyte salt in the electrolyte may include, but is not limited to, one or more of the following: lithium hexafluorophosphate LiPF6, lithium tetrafluoroborate LiBF4, lithium perchlorate LiClO4, lithium hexafluoroarsenate LiAsF6, lithium bis(fluorosulfonyl)imide LiFSI, lithium bis(trifluoromethanesulfonyl)imide LiTFSI, lithium trifluoromethanesulfonate LiTFS, lithium difluorooxalate borate LiDFOB, lithium dioxalate borate LiBOB, lithium difluorophosphate LiPO2F2, lithium difluorodioxalate phosphate LiDFOP, and lithium tetrafluorooxalate phosphate LiTFOP.

[0174] When the battery cell 7 in the embodiments of this application is a sodium-ion battery, as an example, the electrolyte salt in the electrolyte may include, but is not limited to, one or more of the following: sodium hexafluorophosphate NaPF6, sodium tetrafluoroborate NaBF4, sodium perchlorate NaClO4, sodium hexafluoroarsenate NaAsF6, sodium bis(fluorosulfonyl)imide NaFSI, sodium bis(trifluoromethanesulfonyl)imide NaTFSI, sodium trifluoromethanesulfonate NaTFS, sodium difluorooxalate borate NaDFOB, sodium dioxalate borate NaBOB, sodium difluorophosphate NaPO2F2, sodium difluorodioxalate phosphate NaDFOP, and sodium tetrafluorooxalate phosphate NaTFOP.

[0175] As an example, the solvent in the electrolyte may include, but is not limited to, one or more of the following: ethylene carbonate EC, propylene carbonate PC, ethyl methyl carbonate EMC, diethyl carbonate DEC, dimethyl carbonate DMC, dipropyl carbonate DPC, methyl propyl carbonate MPC, ethyl propyl carbonate EPC, butylene carbonate BC, fluoroethylene carbonate FEC, methyl formate MF, methyl acetate MA, ethyl acetate EA, propyl acetate PA, methyl propionate MP, ethyl propionate EP, propyl propionate PP, methyl butyrate MB, ethyl butyrate EB, 1,4-butyrolactone GBL, sulfolane SF, dimethyl sulfone MSM, methyl ethyl sulfone EMS, and diethyl sulfone ESE.

[0176] In this embodiment, the polymer matrix and electrolyte salt can be added to a solvent such as N,N-dimethylformamide, dispersed evenly to obtain a slurry, and then molded to obtain a polymer solid electrolyte.

[0177] In the embodiments of this application, the electrode assembly 10 is a wound structure or a stacked structure, and can be selected as a stacked structure.

[0178] When the electrode assembly 10 has a wound structure, the positive electrode sheet is a single piece and the negative electrode sheet is a single piece, and the positive and negative electrode sheets are wound in the same direction.

[0179] When the electrode assembly 10 has a stacked structure, there are multiple positive electrode sheets and multiple negative electrode sheets, and the multiple positive electrode sheets and multiple negative electrode sheets are stacked.

[0180] like Figure 6 and Figure 7As shown, in some embodiments, the battery cell 7 includes a first buffer assembly 30 and at least one electrode assembly 10. Each electrode assembly 10 includes a main body portion 12 and a tab portion 11 connected to at least one side of the main body portion 12 along a first direction Y. The main body portion 12 includes a positive electrode portion 13 containing a positive electrode active material, a negative electrode portion 14 containing a negative electrode active material, and a solid electrolyte layer 15. The positive electrode portion 13, the solid electrolyte layer 15, and the negative electrode portion 14 are stacked along the thickness direction X of the battery cell 7, and the first direction Y is perpendicular to the thickness direction X. The first buffer assembly 30 is disposed on at least one side of at least one electrode assembly 10 along the thickness direction X, and the projection of the main body portion 12 along the thickness direction X is located within the projection of the first buffer assembly 30 along the thickness direction X.

[0181] The tab 11 can be provided on one or both sides of the main body 12 along the first direction Y.

[0182] Considering at least one electrode assembly 10 as a whole, a first buffer assembly 30 is disposed on at least one side of at least one electrode assembly 10, and the projection of the main body portion 12 of the electrode assembly 10 along the thickness direction X is located within the projection of the first buffer assembly 30 along the thickness direction X.

[0183] like Figure 8 As shown, optionally, the first buffer component 30 is disposed on both sides of at least one electrode component 10.

[0184] The first buffer component 30 is positioned opposite to the large surface of the battery cell 7, effectively buffering and protecting the large surface of the battery cell 7. In this embodiment, the large surface of the battery cell 7 refers to the surface with a relatively large area. For example, the electrode assembly 10 has a cuboid structure and may include four side surfaces and two main surfaces. The area of ​​the main surfaces is larger than that of the side surfaces, and the main surfaces are perpendicular to the thickness direction X. The stress on the main surfaces is more significant. By positioning the first buffer component 30 opposite to the large surface, the large surface can be effectively buffered and protected, thereby effectively buffering and protecting the battery cell 7, reducing the risk of damage to the electrode assembly 10 inside the battery cell 7, reducing the risk of electrode breakage and powder shedding, reducing the risk of short circuit between the positive and negative electrodes, and improving the structural stability and reliability of the battery cell 7.

[0185] Furthermore, it can reduce problems such as large self-discharge and capacity loss of battery cell 7, and further improve the electrical performance of battery cell 7, such as improving the cycle performance and discharge rate performance of battery cell 7.

[0186] like Figure 8 to Figure 10As shown, in some embodiments, the first buffer component 30 extends beyond the electrode assembly 10 along the second direction Z. Specifically, the first buffer component 30 extends beyond the main body portion 12 along the second direction Z. The first buffer component 30 can effectively buffer and protect the electrode assembly 10, improving the structural stability of the battery cell 7. Of course, the dimension of the first buffer component 30 along the second direction Z can also be the same as the dimension of the electrode assembly 10 along the second direction Z, or the dimension of the first buffer component 30 along the second direction Z can also be the same as the dimension of the main body portion 12 along the second direction Z, with their projections in the thickness direction X coinciding.

[0187] Since the electrode assembly 10 in the battery cell 7 is at high risk of damage, the first buffer assembly 30 can effectively improve the structural stability of the battery cell 7 by providing effective buffer protection for the electrode assembly 10. Furthermore, by ensuring that the projection of the first buffer assembly 30 along the thickness direction X is located within the projection of the main body 12 along the thickness direction X, the space occupancy rate of the first buffer assembly 30 can be reduced, thereby increasing the space occupancy rate of the electrode assembly 10. For example, the dimension of the first buffer assembly 30 along the second direction Z is less than or equal to the dimension of the main body 12 along the second direction Z.

[0188] In some embodiments, the tab 11 of the battery cell 7 is connected to at least one side of the main body 12 along the first direction Y, for example, located on one or both sides, with the first direction Y, the second direction Z and the thickness direction X being perpendicular to each other; the first buffer assembly 30 also extends to the connection between the main body 12 of the battery cell 7 and the tab 11, providing effective buffer protection at the connection and reducing the risk of the tab 11 breaking from the connection.

[0189] Furthermore, the first buffer assembly 30 also covers the portion of the tab 11 in the battery cell 7 that is close to the main body 12; even further, the dimension of the portion of the tab 11 close to the main body 12 along the first direction Y is L1, and the dimension of the tab 11 along the first direction Y is L2, where L1 / L2 is greater than 0 and less than or equal to 0.5, for example, 0.05, 0.1, 0.15, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.40, 0.45, 0.5, or any range of two of the above values. The first buffer assembly 30 covering the L1 portion can effectively buffer and protect the connection area between the tab 11 and the main body 12, and provide space for the tab 11 to be assembled with external components.

[0190] In some embodiments, the dimension of the first buffer component 30 along the thickness direction X is H1, and the dimension of the electrode component 10 along the thickness direction X is H2, where H1 / H2 is greater than 0 and less than or equal to 0.3, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, or any combination of two of the above values. When the thickness of the first buffer component 30 is within the above range, it can provide effective buffering and protection without occupying excessive space, thereby achieving an appropriate energy density. Figure 8 In the diagram, H1 represents the dimension of the first buffer component 30 along the thickness direction X, i.e., the thickness of the first buffer component 30, and H2 represents the dimension of the electrode component 10 along the thickness direction X, i.e., the thickness of the electrode component 10.

[0191] In some embodiments, the first buffer component 30 can be a layered structure, such as a single-layer structure or a multi-layer composite structure. Of course, the first buffer component 30 can also be other structural types, such as a frame structure. The layered structure covering the electrode assembly 10 can provide more effective protection and buffering for the battery cell 7.

[0192] One or more pore structures can be incorporated into the layered structure. These pores may or may not penetrate the layered structure along the thickness direction X. By incorporating pore structures, the layered structure can take on a mesh-like or other form. The inclusion of pore structures makes the layered structure lighter, which is beneficial for increasing the gravimetric energy density of the battery cell 7. Of course, the layered structure can also be a solid structure, meaning it basically does not include macroscopic pore structures; however, due to the inherent properties of the material, the layered structure can include structures such as micropores.

[0193] In some embodiments, the first buffer component 30 may be disposed on the surface of the electrode component 10, and the first buffer component 30 and the electrode component 10 may be in contact, but there may be no bonding force between them.

[0194] In other embodiments, the first buffer component 30 can be adhered to the surface of the electrode component 10. The first buffer component 30 has a strong bond with the electrode component 10 and is not prone to positional movement. During the charging and discharging process of the battery cell 7, it can effectively play a buffering and protective role.

[0195] Optionally, the peel strength between the first buffer component 30 and the electrode component 10 is greater than 0 N / m and less than or equal to 30 N / m, for example, 1 N / m, 5 N / m, 8 N / m, 10 N / m, 12 N / m, 13 N / m, 15 N / m, 16 N / m, 18 N / m, 20 N / m, 22 N / m, 25 N / m, 28 N / m, 30 N / m or any two of the above values. When the peel strength is within the above range, the bonding force between the first buffer component 30 and the surface of the electrode component 10 is stronger, and it is not easy for the first buffer component 30 to fall off the electrode component 10.

[0196] In some embodiments, the elastic modulus of the first buffer component 30 is from 5 MPa to 200 MPa, for example, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, or any combination of two of the above values. When the elastic modulus of the first buffer component 30 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0197] In some embodiments, the Poisson's ratio of the first buffer component 30 is between 0.2 and 0.35, for example, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, or any combination of two of the above values. When the Poisson's ratio of the first buffer component 30 is within the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external forces on the battery cell 7.

[0198] In some embodiments, the first buffer component 30 includes one or more of polyolefin polymers, organosiloxane polymers, polyimides, polyurethanes, polyethylene terephthalate, and polystyrene-butadiene copolymers.

[0199] For example, the polyolefin polymer includes one or more of cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and ethylene propylene diene monomer (EPDM) copolymers.

[0200] For example, organosiloxane polymers include one or more of polymethylvinylsiloxane (PMVS), polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0201] The aforementioned materials can exist in the form of rubber pads, such as cis-1,4-polyisoprene rubber.

[0202] In some embodiments, the projection of the negative electrode portion 14 along the thickness direction X lies within the projection of the solid electrolyte layer 15 along the thickness direction X, and the projection of the solid electrolyte layer 15 along the thickness direction X lies within the projection of the first buffer assembly 30 along the thickness direction X. The first buffer assembly 10 can effectively buffer and protect the main body structure of the electrode assembly 10.

[0203] In some embodiments, the battery cell 7 further includes a housing 20 that houses the electrode assembly 10 and the first buffer assembly 30.

[0204] In one specific embodiment of this application, the battery cell 7 includes a first buffer assembly 30 and an electrode assembly 10. Each electrode assembly 10 includes a main body portion 12 and a tab portion 11 connected to one side of the main body portion 12 along the first direction Y. The main body portion 12 includes a positive electrode portion 13 containing a positive electrode active material, a negative electrode portion 14 containing a negative electrode active material, and a solid electrolyte layer 15. The positive electrode portion 13, the solid electrolyte layer 15, and the negative electrode portion 14 are stacked along the thickness direction X of the battery cell 7, and the first direction Y is perpendicular to the thickness direction X. The first buffer assembly 30 is disposed on both sides of the electrode assembly 10 along the thickness direction X, and the projection of the main body portion 12 along the thickness direction X is located within the projection of the first buffer assembly 30 along the thickness direction X. The first buffer assembly 30 extends beyond the main body portion 12 along the second direction Z, and the second direction Z, the first direction Y, and the thickness direction X are all perpendicular to each other.

[0205] Example

[0206] 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.

[0207] Example 1

[0208] The battery cell includes an electrode assembly and a first buffer assembly. The electrode assembly includes a main body and a tab connected to one side of the main body along a first direction. The main body includes a positive electrode portion containing a positive electrode active material, a negative electrode portion containing a negative electrode active material, and a solid electrolyte layer. The positive electrode portion, the solid electrolyte layer, and the negative electrode portion are stacked along the thickness direction of the battery cell, and the first direction is perpendicular to the thickness direction. The first buffer assembly is disposed on both sides of the electrode assembly along the thickness direction, and the projection of the main body along the thickness direction is located within the projection of the first buffer assembly along the thickness direction.

[0209] Examples 2-1 to 2-3

[0210] Battery cells were prepared using a method similar to that of Example 1, except that the material of the first buffer component was adjusted.

[0211] Examples 3-1 and 3-2

[0212] Battery cells were prepared using a method similar to that of Example 1, except that the thickness of the first buffer component was adjusted.

[0213] Example 4

[0214] Battery cells were prepared using a method similar to that of Example 1, except that the values ​​of L1 / L2 were adjusted.

[0215] Comparative Example 1

[0216] The battery cell includes an electrode assembly, which includes a main body and a tab connected to one side of the main body along a first direction. The main body includes a positive electrode portion containing a positive electrode active material, a negative electrode portion containing a negative electrode active material, and a solid electrolyte layer. The positive electrode portion, the solid electrolyte layer, and the negative electrode portion are stacked along the thickness direction of the battery cell, and the first direction is perpendicular to the thickness direction.

[0217] Performance test

[0218] In this application, the electrical performance of the battery cells can be tested using instruments and methods known in the art, such as in accordance with GB / T 31486-2015 Electrical Performance Requirements and Test Methods for Power Batteries for Electric Vehicles and GB / T31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles.

[0219] Specifically, cycle life can be tested using the following method: The battery cells prepared in the examples and comparative examples are subjected to the following cycle tests at 25°C:

[0220] 1) Let stand for 30 minutes;

[0221] 2) Charge at a 0.33C rate to the cutoff upper limit voltage;

[0222] 3) Let it sit for 30 minutes;

[0223] 4) Discharge at a rate of 0.33C to the cutoff voltage;

[0224] 5) Let it sit for 30 minutes;

[0225] 6) Repeat steps 2) to 5) until the capacity of a single battery cell decreases to 80% of its initial capacity, and record the number of cycles.

[0226] The number of cycles in Comparative Example 1 is equal to 1. For other embodiments, the number of cycles is calculated relative to the number of cycles in Comparative Example 1. For example, the number of cycles in Comparative Example 1 is 500 cycles and the number of cycles in Embodiment 1 is 625 cycles. In the table, it is shown that the number of cycles in Comparative Example 1 is 1 and the number of cycles in Embodiment 1 is 625 / 500 = 1.25.

[0227] The discharge rate can be tested using the following methods:

[0228] At 25°C, the battery cells prepared in the examples and comparative examples were charged at a 1C rate to the upper limit of the charging cutoff voltage and discharged at a 1C rate to the discharge cutoff voltage, and the discharge capacity was calculated. The discharge capacity of Comparative Example 1 was taken as 1, and for other examples, the relative discharge capacity was calculated based on the discharge capacity of Comparative Example 1.

[0229] Test results

[0230] The test results are shown in Table 1.

[0231] Table 1

[0232]

[0233] As can be seen from Table 1,

[0234] Compared to Comparative Example 1, Example 1 uses a polyurethane-based first buffer component, which can effectively improve the reliability of the battery cell and further improve the electrical performance of the battery cell, such as improving cycle performance by 25% and discharge rate performance by 20%.

[0235] First buffer components made of different materials can generally improve the electrical performance of individual battery cells. However, the degree of protection provided by different materials to individual battery cells varies, resulting in differences in electrical performance. The order of their impact on electrical performance is as follows: polyethylene terephthalate > polyurethane > silicone rubber > polyimide.

[0236] The thickness of the first buffer component affects the electrical performance of the battery cell. The thicker the first buffer component, the better the electrical performance of the battery cell, but it is not conducive to improving the energy density.

[0237] The longer the length of the first buffer component covering the tab, the better it is to reduce the risk of tab breakage and improve the reliability of the battery cell; however, it is not conducive to improving the energy density of the battery cell and the assembly of the tab and other components; overall, when L1 / L2 is greater than 0 and less than or equal to 0.5, it is conducive to the overall improvement of the reliability of the battery cell.

[0238] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the implementation of the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the implementation of the present application.

Claims

1. A battery cell comprising: at least one electrode assembly, each of the electrode assemblies including a main body portion and a tab portion connected to at least one side of the main body portion in a first direction, the main body portion including a positive electrode portion including a positive electrode active material, a negative electrode portion including a negative electrode active material, and a solid electrolyte layer, the positive electrode portion, the solid electrolyte layer, and the negative electrode portion being stacked in a thickness direction of the battery cell, the first direction being perpendicular to the thickness direction; and a first buffer assembly provided on at least one side of the at least one electrode assembly in the thickness direction, a projection of the main body portion in the thickness direction being located within a projection of the first buffer assembly in the thickness direction. The first buffer assembly is provided on both sides of the at least one electrode assembly in the thickness direction.

2. The battery cell of claim 1, wherein, The first buffer assembly extends beyond the main body portion in a second direction, the second direction, the first direction, and the thickness direction being perpendicular to each other.

3. The battery cell of claim 1 or 2, wherein, The first buffer assembly also covers a portion of the tab portion close to the main body portion.

4. The battery cell of any one of claims 1 to 3, wherein, A dimension of the portion of the tab portion close to the main body portion in the first direction is L1, a dimension of the tab portion in the first direction is L2, L1 / L2 is greater than 0 and less than or equal to 0.

5.

5. The battery cell of claim 4, wherein, A dimension of the first buffer assembly in the thickness direction is H1, a dimension of the electrode assembly in the thickness direction is H2, H1 / H2 is greater than 0 and less than or equal to 0.

3.

6. The battery cell of any one of claims 1 to 5, wherein, The first buffer assembly has a layered structure.

7. The battery cell of any one of claims 1 to 6, wherein, The layered structure includes one or more hole structures.

8. The battery cell of claim 7, wherein, The first buffer assembly is adhered to at least one side of the at least one electrode assembly in the thickness direction.

9. The battery cell of any one of claims 1-8, wherein, A peeling strength between the first buffer assembly and the electrode assembly is greater than 0 N / m and less than or equal to 30 N / m.

10. The battery cell of any one of claims 1 to 9, wherein, An elastic modulus of the first buffer assembly is 5 MPa to 200 MPa.

11. The battery cell of any one of claims 1-10, wherein, A Poisson's ratio of the first buffer assembly is 0.2 to 0.

35.

12. The battery cell of any one of claims 1-11, wherein, The first buffer assembly includes one or more of a polyolefin-based polymer, an organosiloxane-based polymer, a polyimide, a polyurethane, a polyethylene terephthalate, and a polystyrene butadiene copolymer.

13. The battery cell of any one of claims 1-12, wherein, The polyolefin-based polymer includes one or more of a polypropylene, a cis-1,4-polyisoprene, a cis-1,4-polybutadiene, a polychloroprene, and a terpolymer of ethylene-propylene.

14. The battery cell of claim 13, wherein, The organosiloxane-based polymer includes one or more of a polymethylvinylsiloxane, a polymethylphenylvinylsiloxane, and a polyfluorosiloxane.

15. The battery cell of claim 13 or 14, wherein, 16.The battery cell according to any one of claims 1 to 15, wherein a projection of the negative electrode portion in the thickness direction is located within a projection of the solid electrolyte layer in the thickness direction, and a projection of the solid electrolyte layer in the thickness direction is located within a projection of the first buffer assembly in the thickness direction. 17.The battery cell according to any one of claims 1 to 16, further comprising a case that accommodates the electrode assembly and the first buffer assembly. 18.A battery device including at least one battery cell according to any one of claims 1 to 17. ​ 19. The battery device according to claim 18, further comprising a second buffer member provided on at least one side of the at least one battery cell in the thickness direction, a projection of the main portion of the battery cell in the thickness direction being located within a projection of the second buffer member in the thickness direction.

20. A battery device comprising: at least one battery cell, each of the battery cells including at least one electrode member, each of the electrode members including a main portion and a tab portion connected to at least one side of the main portion in a first direction, the main portion including a positive electrode portion including a positive electrode active material, a negative electrode portion including a negative electrode active material, and a solid electrolyte layer, the positive electrode portion, the solid electrolyte layer, and the negative electrode portion being stacked in a thickness direction of the battery cell, the first direction being perpendicular to the thickness direction; and a second buffer member provided on at least one side of the at least one battery cell in the thickness direction, a projection of the main portion in the thickness direction being located within a projection of the second buffer member in the thickness direction. The second buffer member is provided on both sides of the at least one battery cell in the thickness direction.

21. The battery device of claim 19 or 20, wherein, The battery cells are a plurality of battery cells, and the second buffer member is provided between adjacent two of the battery cells.

22. The battery device of any one of claims 19-21, wherein, The second buffer member extends beyond the main portion in a second direction, the second direction, the first direction, and the thickness direction being perpendicular to each other.

23. The battery device of any one of claims 19-22, wherein, A projection of the second buffer member in the thickness direction is located within a projection of the battery cell in the thickness direction.

24. The battery device of any one of claims 19-23, wherein, The second buffer member also covers a portion of the tab portion close to the main portion.

25. The battery device of any one of claims 19-24, wherein, A dimension of the second buffer member in the thickness direction is H3, and a dimension of the battery cell in the thickness direction is H4, H3 / H4 being greater than 0 and less than or equal to 0.

35.

26. The battery device of any one of claims 19-25, wherein, The second buffer member is a layered structure.

27. The battery device of any one of claims 19-26, wherein, The layered structure includes one or more hole structures.

28. The battery device of claim 27, wherein, The second buffer member is adhered to at least one side of the at least one battery cell in the thickness direction.

29. The battery device of any one of claims 19-28, wherein, A peeling strength between the second buffer member and a housing of the battery cell is greater than 0 N / m and less than or equal to 30 N / m.

30. The battery device of any one of claims 19-29, wherein, An elastic modulus of the second buffer member is 5 MPa to 200 MPa.

31. The battery device of any one of claims 19-30, wherein, A Poisson's ratio of the second buffer member is 0.2 to 0.

35.

32. The battery device of any one of claims 19-31, wherein, The second buffer member includes one or more of a polyolefin-based polymer, an organosiloxane-based polymer, a polyimide, a polyurethane, a polyethylene terephthalate, and a polystyrene butadiene copolymer.

33. The battery device of any one of claims 19-32, wherein, 34. The battery device according to claim 33, wherein the polyolefin-based polymer includes one or more of polypropylene, cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and terpolymer of ethylene-propylene; the organosiloxane-based polymer includes one or more of polymethylvinylsiloxane PMVS, polymethylphenylvinylsiloxane, and polyfluorosiloxane.

35. An electric device including the battery device according to any one of claims 19 to 34. ​

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