Battery cell, battery device, and electric device

Abstract

A battery cell, a battery device, and an electric device. The battery cell comprises a first cushioning assembly and at least one electrode assembly; each electrode assembly comprises 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 comprises 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 in the thickness direction of the battery cell, and the first direction is perpendicular to the thickness direction; and the first cushioning assembly is provided on at least one side of the at least one electrode assembly in the thickness direction, and a projection of the main body portion in the thickness direction is located within a projection of the first cushioning assembly in the thickness direction. The use reliability of the battery cell can be improved.

Description

Battery cell, battery device, and powered device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411244103.2, filed on September 5, 2024, entitled “Battery cell, battery device, and powered device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to a battery cell, a battery device, and a powered device. BACKGROUND

[0004] Battery cells have characteristics such as high capacity and long service life, and are therefore 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, among others. Due to the great progress made in batteries, higher requirements are placed on the performance of batteries.

[0005] However, the use reliability of battery cells is still poor. SUMMARY

[0006] The present application provides a battery cell, a battery device, and a powered device, and the use reliability of the battery cell described in the present application can be improved.

[0007] 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 portion and a tab portion connected to at least one side of the main body portion along a first direction, the main body portion comprising a positive electrode portion containing a positive electrode active material, a negative electrode portion containing a negative electrode active material, and a solid-state electrolyte layer, the positive electrode portion, the solid-state electrolyte layer, and the negative electrode portion being stacked along a thickness direction of the battery cell, the first direction being perpendicular to the thickness direction; the first buffer assembly being disposed on at least one side of the at least one electrode assembly along the thickness direction, a projection of the main body portion along the thickness direction being located within a projection of the first buffer assembly along the thickness direction.

[0008] 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 loss, reduce the risk of positive and negative electrode contact short circuit, and improve the structural stability and use reliability of the battery cell.

[0009] In some embodiments, the first buffer assembly is disposed 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.

[0010] In some embodiments, the first buffer assembly extends beyond the body portion along a second direction, the second direction, the first direction and the thickness direction being perpendicular to each other. The first buffer assembly can effectively protect the electrode assembly, and improve the structural stability of the battery cell.

[0011] In some embodiments, the first buffer assembly further 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 region between the tab portion and the body portion, and provide space for assembling the tab portion with external components.

[0012] In some embodiments, the size of the portion of the tab portion close to the body portion along the first direction is L1, the size of the tab portion along the first direction is L2, and 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 region between the tab portion and the body portion, and provide space for assembling the tab portion with external components.

[0013] In some embodiments, the size of the first buffer assembly along the thickness direction is H1, and the size of the electrode assembly along the thickness direction is H2, and 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 without occupying too much space, thereby balancing the appropriate energy density.

[0014] 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.

[0015] In some embodiments, the layered structure comprises one or more hole structures. The hole structures make the layered structure lighter, which is conducive to improving the weight energy density of the battery cell.

[0016] In some embodiments, the first buffer assembly is adhered to at least one side of the electrode assembly along the thickness direction. The first buffer assembly has 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.

[0017] 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 strong bonding force with the surface of the electrode assembly and is not prone to falling off from the electrode assembly.

[0018] In some embodiments, the elastic modulus of the first buffer assembly is 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.

[0019] In some embodiments, the Poisson's ratio of the first buffer assembly is 0.2 to 0.35. When the Poisson's ratio of the first buffer assembly is in the above range, the first buffer assembly has excellent elastic deformation capability and can effectively buffer the stress problems caused by internal and external actions of the battery cell.

[0020] In some embodiments, the first buffer assembly comprises one or more of a polyolefin-based polymer, an organosiloxane-based polymer, a polyimide, a polyurethane, a polyethylene terephthalate, and a polystyrene butadiene copolymer.

[0021] 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.

[0022] In some embodiments, the organosiloxane-based polymer comprises one or more of polymethylvinylsiloxane, polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0023] In some embodiments, the projection of the negative electrode portion along the thickness direction is located within the 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 the 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.

[0024] In some embodiments, the battery cell further comprises a shell, and the shell accommodates the electrode assembly and the first buffer assembly.

[0025] In a second aspect, the embodiments of the present application further provide a battery device comprising the battery cell of any one of the embodiments of the first aspect of the present application.

[0026] In some embodiments, the battery device further comprises a second buffer assembly, and the second buffer assembly is arranged on at least one side of the at least one battery cell along the thickness direction, and the projection of the main body portion of the battery cell along the thickness direction is located within the projection of the second buffer assembly along the thickness direction.

[0027] Thus, 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 electrode 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 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] In some embodiments, the second buffer assembly further covers a part of the tab part close to the main body part. The first buffer assembly covers a part of the tab part, can effectively buffer and protect the connection area of the tab part and the main body part, and provides a space for assembling the tab part and an external component.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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 from the electrode assembly.

[0040] 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 problem caused by the internal and external effects of the battery cell.

[0041] 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 problem caused by the internal and external effects of the battery cell.

[0042] 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.

[0043] In some embodiments, the polyolefin-based polymer includes one or more of polypropylene, cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and terpolymer.

[0044] In some embodiments, the organosiloxane-based polymer comprises one or more of polymethylvinylsiloxane (PMVS), polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0045] In a fourth aspect, the embodiments of the present application further provide a battery device, comprising the battery device according to any one of the embodiments of the second aspect or the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0046] 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 of the 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.

[0047] FIG. 1 is a schematic diagram of an embodiment of a vehicle of the present application.

[0048] FIG. 2 is a schematic diagram of an embodiment of a battery pack of the present application.

[0049] FIG. 3 is a schematic diagram of an embodiment of a battery module of the present application.

[0050] FIG. 4 is a schematic diagram of an embodiment of a battery module and a second buffer assembly of the present application.

[0051] FIG. 5 is a schematic diagram of an embodiment of a battery pack and a second buffer assembly of the present application.

[0052] FIG. 6 is a schematic diagram of a structure of a battery cell of the present application.

[0053] FIG. 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.

[0054] FIG. 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.

[0055] FIG. 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.

[0056] FIG. 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.

[0057] The drawings are not necessarily drawn to scale.

[0058] The reference numerals are explained as follows: X, thickness direction; Y, first direction; Z, second direction; 1, electric device; 2, battery pack; 3, controller; 4, motor; 5, case; 5a, first case portion; 5b, second case portion; 5c, accommodation space; 6, battery module; 7, battery cell; 10, electrode assembly; 11, tab portion; 111, positive electrode tab; 112, negative electrode tab; 12, main body portion; 13, positive electrode portion; 14, negative electrode portion; 15, solid electrolyte layer; 20, housing; 30, first buffer assembly; 8, second buffer assembly. DETAILED DESCRIPTION

[0059] Hereinafter, embodiments of the battery cell, the battery device, and the electric device of the present application are specifically disclosed with appropriate reference to the accompanying drawings. However, there are cases where unnecessary detailed explanations are omitted. For example, there are cases where detailed explanations of matters that are already well known, repeated explanations 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 explanations 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.

[0060] The "ranges" disclosed in the present application are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The ranges defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if a minimum range value of 1 and 2 is listed, and if a maximum range value of 3, 4, and 5 is listed, then the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In the present application, unless otherwise stated, a numerical range "a to b" represents a shorthand manner of describing each and every numerical value that is contained in the range between "a" and "b," wherein "a" and "b" are both real numbers. For example, the numerical range "0 to 5" indicates that all real numbers between "0" and "5" have been listed herein, and "0 to 5" is merely a shorthand manner of describing each and every numerical value that is contained in the range between "0" and "5." In addition, when it is stated that a certain parameter is an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and the like.

[0061] All embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, if not otherwise specified.

[0062] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0063] If not specifically stated, all steps of the present application can be performed in sequence or randomly, preferably in sequence. 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.

[0064] In the present application, "a plurality of" refers to two or more (including two).

[0065] In the present application, the battery cell can include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc. The present application embodiments are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc. The present application embodiments are also not limited thereto. The battery cell is generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft package battery cells. Optionally, the battery cell of the present application can be a soft package battery cell.

[0066] The battery device mentioned in the embodiments of the present application can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, in parallel, or in a mixed connection through a busbar component.

[0067] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0068] In some embodiments, the battery device can be a battery pack, which includes a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body.

[0069] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be accommodated in the box body by fixing the battery module in the box body.

[0070] As an example, the battery cell assembly can also be accommodated in the box body by directly fixing a plurality of battery cells in the box body.

[0071] In the case that the electrode assembly of the battery cell comprises a solid electrolyte layer, the electrode assembly is relatively fragile and is prone to damage. During the charging and discharging process of the battery cell, the battery cell may expand in volume, resulting in internal stress in the battery cell. The battery cell may also be subjected to external forces. Either the internal stress or the external forces may cause damage to the electrode assembly, resulting in poor structural stability and poor reliability of the battery cell.

[0072] The application embodiments provide a battery device and a battery cell, and the battery device and the battery cell have the advantages of high structural stability, high cycle life, and high reliability.

[0073] The battery cell described in the application embodiments is suitable for a battery device and a power consumption device using the battery device.

[0074] The power consumption device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, for example, a game console, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer, etc. The application embodiments do not specially limit the above power consumption devices.

[0075] The following embodiments take the power consumption device as a vehicle for example for convenience of description.

[0076] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the application.

[0077] As shown in FIG. 1, the vehicle 1 is internally provided with a battery pack 2, which can be arranged at the bottom, the head, or the tail of the vehicle 1. The battery pack 2 can be used for power supply of the vehicle 1, for example, the battery pack 2 can be used as an operating power source of the vehicle 1.

[0078] The vehicle 1 can further include a controller 3 and a motor 4, and the controller 3 is used to control the battery pack 2 to supply power to the motor 4, for example, to meet the working power demand of the vehicle 1 during starting, navigation, and driving.

[0079] In some embodiments of the application, the battery pack 2 can not only be used as an operating power source of the vehicle 1, but also be used as a driving power source of the vehicle 1, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1.

[0080] Figure 2 is an exploded schematic view of a battery pack according to some embodiments of the present application. As shown in Figure 2, the battery pack 2 includes a box 5 and battery cells (not shown in Figure 2), which are accommodated in the box 5.

[0081] The box 5 is used to accommodate the battery cells, and the box 5 can have various structures. In some embodiments, the box 5 can include a first box part 5a and a second box part 5b, the first box part 5a and the second box part 5b are mutually coverable, and the first box part 5a and the second box part 5b together define an accommodation space 5c for accommodating the battery cells. The second box part 5b can be a hollow structure with one end open, and the first box part 5a can be a plate-like structure, which covers the open side of the second box part 5b to form the box 5 with the accommodation space 5c; or the first box part 5a and the second box part 5b can both be hollow structures with one side open, and the open side of the first box part 5a covers the open side of the second box part 5b to form the box 5 with the accommodation space 5c. Of course, the first box part 5a and the second box part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0082] To improve the sealing performance of the first box part 5a and the second box part 5b after being connected, a sealing member, such as a sealing glue, a sealing ring, etc., can be arranged between the first box part 5a and the second box part 5b.

[0083] Suppose the first box part 5a covers the top of the second box part 5b, the first box part 5a can also be referred to as an upper box cover, and the second box part 5b can also be referred to as a lower box.

[0084] In the battery pack 2, the battery cells can be one or multiple. If the battery cells are multiple, the multiple battery cells can be connected in series, in parallel, or in a mixed manner, where the mixed manner means that the multiple battery cells are connected in series and in parallel. The multiple battery cells can be directly connected in series, in parallel, or in a mixed manner, and then the whole of the multiple battery cells is accommodated in the box 5; of course, the multiple battery cells can first be connected in series, in parallel, or in a mixed manner to form a battery module 6, and then the multiple battery modules 6 are connected in series, in parallel, or in a mixed manner to form a whole, which is accommodated in the box 5.

[0085] The battery cell can be the smallest unit constituting a battery device.

[0086] Figure 3 is a structural schematic view of the battery module 6 shown in Figure 2.

[0087] In some embodiments, as shown in Figure 3, the battery cells 7 are multiple, and the multiple battery cells 7 are first connected in series, in parallel, or in a mixed manner to form the battery module 6. Then, the multiple battery modules 6 are connected in series, in parallel, or in a mixed manner to form a whole, which is accommodated in the box.

[0088] The plurality of battery cells 7 in the battery module 6 can be electrically connected through busbar components to realize parallel connection, series connection or mixed connection of the plurality of battery cells 7 in the battery module 6. The busbar components can be one or more, and each busbar component is used to electrically connect at least two battery cells 7.

[0089] When the battery device includes a plurality of battery cells 7, the plurality of battery cells 7 can be stacked along the thickness direction X of the battery cells 7 to assemble a battery pack; or the plurality of battery cells 7 can be grouped, each group of battery cells 7 is stacked along the thickness direction X to form a battery module 6, and then each battery module 6 is assembled into a battery pack.

[0090] In some embodiments, the battery device further includes a buffer assembly, for example, the buffer assembly includes a second buffer assembly 8, and the second buffer assembly 8 is arranged on at least one side of at least one battery cell 7 along the thickness direction X.

[0091] As shown in FIGS. 3 and 4, 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, and the second buffer assembly 8 is arranged on at least one side of the at least one battery cell 7, for example, the second buffer assembly 8 is arranged 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 part 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 arranged 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 second buffer assembly 8 is arranged on both sides of the plurality of battery cells 7 as a whole.

[0092] The second buffer assembly 8 can effectively buffer and protect the large face of the battery cell 7. In the embodiments of the present application, the large face of the battery cell 7 refers to the face with a relatively large area of the battery cell 7, for example, the electrode assembly 10 has a cuboid structure, and the electrode assembly 10 can include four side faces and two main faces, the area of the main face is larger than that of the side face, the main face is perpendicular to the thickness direction X, and the stress acting on the main face is more significant. Arranging the second buffer assembly 8 opposite to the large face can effectively buffer and protect the large face, thereby effectively buffering and protecting the battery cell 7, reducing the risk of damage to the electrode assembly 10 in the battery cell 7, reducing the risk of broken positive and negative plates and powder falling off, reducing the risk of positive and negative contact short circuit, reducing the problems of large self-discharge of the battery cell 7, capacity loss and the like, and improving the structural stability and use reliability of the battery cell 7, thereby improving the structural stability of the battery device.

[0093] Further, the second buffer assembly 8 can also be arranged between two adjacent battery cells 7 to further improve the buffering and protection effect of the battery cell 7.

[0094] In some embodiments, the second buffering assembly 8 extends beyond the electrode assembly 10 along the second direction Z, in particular, the second buffering assembly 8 extends beyond the main body portion 12 along the second direction Z. The second buffering assembly 8 can effectively protect the electrode assembly 10 in the battery cell 7, and improve the structural stability of the battery pack. Of course, the size of the second buffering assembly 8 along the second direction Z can also be the same as the size of the electrode assembly 10 along the second direction Z, or the projections of the two along the thickness direction X coincide.

[0095] Since the electrode assembly 10 in the battery cell 7 is at greater risk of damage, the second buffering assembly 8 can effectively protect the electrode assembly 10 and improve the structural stability of the battery cell 7. Further, the projection of the second buffering assembly 8 along the thickness direction X is located within the projection of the battery cell 7 along the thickness direction X, which can reduce the space occupancy of the second buffering assembly 8, improve the space occupancy of the battery cell 7, and help improve the volumetric energy density of the battery module 6. For example, the size of the second buffering assembly 8 along the second direction Z can be the same as the size of the battery cell 7 along the second direction Z, or the size of the second buffering assembly 8 along the second direction Z is smaller than the size of the battery cell 7 along the second direction Z.

[0096] In some embodiments, the tab portion 11 of the battery cell 7 is connected to at least one side of the main body portion 12 along the first direction Y, the first direction Y, the second direction Z, and the thickness direction X are perpendicular to each other; the second buffering assembly 8 also extends to the connection between the main body portion 12 and the tab portion 11 of the battery cell 7, effectively protecting the connection and reducing the risk of the tab portion 11 breaking from the connection.

[0097] Further, the second buffering assembly 8 also covers the part of the tab portion 11 of the battery cell 7 close to the main body portion 12; further, the size of the part of the tab portion 11 close to the main body portion 12 along the first direction Y is L1, the size of the tab portion 11 along the first direction Y is L2, and L1 / L2 is greater than 0 and less than or equal to 0.5. The second buffering assembly 8 covers the L1 part, which can effectively protect the tab portion 11 and provide space for the tab portion 11 to assemble with external components.

[0098] In some embodiments, the second buffering assembly 8 has a dimension H3 along the thickness direction X, and the battery cell 7 has a dimension 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 defined by any two of the above values. When the thickness of the second buffering assembly 8 is within the above range, the second buffering assembly 8 can effectively protect the battery cell 7, and does not occupy too much space, thereby achieving a proper energy density. In FIG. 4, H3 represents the dimension of the second buffering assembly 8 along the thickness direction X, i.e., the thickness of the second buffering 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.

[0099] In some embodiments, the second buffering assembly 8 can have a layered structure, for example, a single-layer structure or a multi-layer composite structure. Of course, the second buffering assembly 8 can also have other structure types, for example, a frame structure, etc. The layered structure covers a large surface of the battery cell 7, and can more effectively protect the battery cell 7.

[0100] One or more hole structures can be provided in the layered structure, and the holes can or can not penetrate the layered structure along the thickness direction X. The hole structures can make the layered structure have a mesh-like shape, etc. The hole structures can make the layered structure lighter, which is beneficial to improving the weight energy density of the battery device. Of course, the layered structure can also be a solid structure, i.e., it basically does not include macroscopic hole structures. However, due to the characteristics of the material itself, the layered structure can include micro-holes, etc.

[0101] In some embodiments, the second buffering assembly 8 can be arranged on the surface of the battery cell 7, and the second buffering assembly 8 and the shell 20 of the battery cell 7 can be in contact, and there can be no bonding force between them.

[0102] In other embodiments, the second buffering assembly 8 can be arranged on the surface of the battery cell 7, and the second buffering assembly 8 and the battery cell 7 have a strong bonding force, and are not prone to position movement. In the charging and discharging process of the battery device, the second buffering assembly 8 can effectively protect the battery cell 7.

[0103] Optionally, the peeling strength between the second buffering assembly 8 and the shell 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 a range defined by any two of the above values. When the peeling strength is within the above range, the second buffering assembly 8 and the surface of the battery cell 7 have a strong bonding force, and are not prone to falling off from the battery cell 7.

[0104] In the embodiments of the present application, the peeling strength between the second cushioning assembly 8 and the outer shell 20 is the meaning known in the art, which can be tested by using the devices and methods known in the art, for example, according to GB / T 2792-2014 Test Method for Adhesive Tape Peeling Strength.

[0105] In some embodiments, the second cushioning assembly 8 has an elastic modulus of 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 a range between any two of the above values. When the second cushioning assembly 8 has an elastic modulus in the above range, it has excellent elastic deformation capability and can effectively buffer the stress caused by internal and external actions of the battery monomer 7.

[0106] In the present application, the elastic modulus of the material is the meaning known in the art, which can be detected by using the instruments and methods known in the art, for example, according to GB / T 14694-1993 Determination of Compression Elastic Modulus of Plastics.

[0107] In some embodiments, the second cushioning assembly 8 has a Poisson's ratio of 0.2 to 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 a range between any two of the above values. When the second cushioning assembly 8 has a Poisson's ratio in the above range, it has excellent elastic deformation capability and can effectively buffer the stress caused by internal and external actions of the battery monomer 7.

[0108] In the present application, the Poisson's ratio of the material is the meaning known in the art, which can be detected by using the instruments and methods known in the art, for example, according to GB / T 1040.1-2018 Determination of Tensile Properties of Plastics Part 1: General Principles (ISO 527-1:2012).

[0109] In some embodiments, the second cushioning assembly 8 comprises one or more of polyolefin-based polymers, organosiloxane-based polymers, polyimides, polyurethanes, polyethylene terephthalate, and polystyrene butadiene copolymers.

[0110] Exemplarily, the polyolefin-based polymer includes one or more of cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and terpolymer of ethylene-propylene.

[0111] Exemplarily, the organosiloxane-based polymer includes one or more of polymethylvinylsiloxane PMVS, polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0112] The above-mentioned material can exist in the form of a rubber pad, such as cis-1,4-polyisoprene rubber, etc.

[0113] As shown in FIG. 5, in the case of the battery device being a battery pack, the battery pack includes a plurality of battery modules 6, which can be arranged in a stacked manner along the thickness direction X, and the second buffer assembly 8 can be arranged on at least one side of the plurality of battery modules 6 along the thickness direction X, thereby effectively buffering and protecting the battery monomers 7 in the battery modules 6. Optionally, the second buffer assembly 8 can also be arranged on both sides of the plurality of battery modules 6 along the thickness direction X.

[0114] Further, the second buffer assembly 8 can also be arranged between two adjacent battery modules 6, which can further improve the buffering and protection effect on the battery modules 6.

[0115] In some embodiments, the size of the second buffer assembly 8 along the thickness direction X is H3, the size of the battery monomer 7 along the thickness direction X is H4, 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 composed of any two of the above-mentioned values. When the thickness of the second buffer assembly 8 is in the above-mentioned range, it can effectively play a buffering and protection role, and at the same time, it will not occupy too much space, thereby being able to take into account the appropriate energy density.

[0116] In some embodiments, the second buffer assembly 8 can have a layered structure, such as a single-layer structure or a multi-layer composite structure. Of course, the second buffer assembly 8 can also have other structure types, such as a frame structure, etc. The layered structure covers the surface of the battery module 6, which can more effectively protect and buffer the battery monomer 7.

[0117] One or more hole structures can be arranged in the layered structure, which can or can not penetrate the layered structure along the thickness direction X. Through the arrangement of the hole structure, the layered structure can present a mesh-like form. The arrangement of the hole structure makes the layered structure lighter in weight, which is beneficial to improve the weight energy density of the battery device. Of course, the layered structure can also be a solid structure, i.e., it basically does not include a macroscopic hole structure; however, due to the characteristics of the material itself, the layered structure can include a micro-hole structure, etc.

[0118] In some embodiments, the second buffer assembly 8 can be disposed on a surface of the battery module 6, and the second buffer assembly 8 can be in contact with the housing 20 of the battery module 6 without any bonding force therebetween.

[0119] In some other embodiments, the second buffer assembly 8 can be adhered to a surface of the battery module 6, and the second buffer assembly 8 can have a strong bonding force with the battery module 6 and can not be easily moved in position. During the charging and discharging process of the battery pack, the second buffer assembly 8 can effectively play a buffering and protection role.

[0120] Optionally, the peeling strength between the second buffer assembly 8 and the housing 20 is greater than 0 N / m and less than or equal to 30 N / m, such as 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 a range formed by any two of the above values. When the peeling strength is in the above range, the second buffer assembly 8 has a strong bonding force with the surface of the battery module 6 and can not be easily detached from the second buffer assembly 8.

[0121] In some embodiments, the second buffer assembly 8 has an elastic modulus of 5 MPa to 200 MPa, such as 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 a range formed by any two of the above values. When the elastic modulus of the second buffer assembly 8 is in the above range, the second buffer assembly 8 has excellent elastic deformation capability and can effectively buffer the stress problems caused by internal and external actions of the battery cell 7.

[0122] In some embodiments, the second buffer assembly 8 has a Poisson's ratio of 0.2 to 0.35, such as 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 a range formed by any two of the above values. When the Poisson's ratio of the second buffer assembly 8 is in the above range, the second buffer assembly 8 has excellent elastic deformation capability and can effectively buffer the stress problems caused by internal and external actions of the battery cell 7.

[0123] As shown in FIG. 6, in some embodiments, the battery cell 7 includes an electrode assembly 10 and a housing 20, and the electrode assembly 10 is accommodated in the housing 20.

[0124] The shell 20 can be in various shapes, such as a cylinder, a cuboid, etc. The shape of the shell 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is in a cylindrical structure, the shell 20 can be selected to be in a cylindrical structure. If the electrode assembly 10 is in a cuboid structure, the shell 20 can be selected to be in a cuboid structure. Alternatively, the shell 20 is in a cuboid structure.

[0125] The material of the shell 20 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the embodiments of the present application do not make special limitations thereon. Alternatively, the inner wall of the shell 20 can further include an insulating layer, which can separate the shell 20 and the electrode assembly 10 to reduce the risk of short circuit. The material of the insulating layer can be selected from the commonly used materials in the art, and no special limitations are made herein.

[0126] The electrode assembly 10 accommodated in the shell 20 can be one or more.

[0127] As shown in FIG. 7, from the appearance 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 tab 111 and a negative tab 112, the polarities of the positive tab 111 and the negative tab 112 are opposite, and the positive tab 111 and the negative tab 112 respectively protrude from the main body portion 12. The positive tab 111 is a part of a positive tab sheet that is not coated with a positive active material layer, and a part of the positive tab sheet that is coated with the positive active material layer is a positive portion 13. The negative tab 112 is a part of a negative tab sheet that is not coated with a negative active material layer, and a part of the negative tab sheet that is coated with the negative active material layer is a negative portion 14. The negative tab 112 and the negative tab 112 are used to lead out the current in the main body portion 12.

[0128] The positive tab 111 and the negative tab 112 can be led out from the same end of the main body portion 12, or the positive tab 111 and the negative tab 112 can be led out from opposite ends of the main body portion 12, respectively.

[0129] The electrode assembly 10 includes a positive tab sheet and a negative tab sheet, and a solid electrolyte layer 15. During the charging and discharging process of the battery cell 7, active ions (such as lithium ions) are embedded and extracted between the positive tab sheet and the negative tab sheet.

[0130] The positive portion 13 includes a positive current collecting portion and a positive active material layer disposed on at least one side of the positive current collecting portion.

[0131] As an example, the positive current collecting portion has two opposite surfaces in the thickness direction X thereof, and the positive active material layer is disposed on any one or both of the two opposite surfaces of the positive current collecting portion.

[0132] As an example, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, titanium, silver surface-treated aluminum, or stainless steel, etc. can be employed. The composite current collector can 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 base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0133] As an example, when the battery cell 7 of the embodiment of the present application is a lithium ion battery, the positive electrode active material can include one or more of the following materials: phosphate, layered transition metal oxide, and each modified compound thereof; optionally, the positive electrode active material can include layered transition metal oxide and each modified compound thereof, which is advantageous to improve the energy density of the battery cell 7. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material layer can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination.

[0134] Examples of the phosphate can include, but are not limited to, one or more of lithium iron phosphate (such as LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0135] The layered transition metal oxide includes one or more of a compound of the general formula Li a Ni b Co c M d O e A f and a modified compound thereof. 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.

[0136] Examples of the layered transition metal oxide can include, but are not limited to, one or more of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM 333 ), LiNi 0.5Co 0.2 Mn 0.3 O2(also can be referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also can be referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also can be referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also can be referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2), and modified compounds thereof.

[0137] When the battery cell 7 of the embodiment of the present application is a sodium ion battery or a sodium metal battery, the positive electrode active material can include, but is not limited to, one or more of sodium-containing transition metal oxides, polyanion materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), Prussian blue type materials.

[0138] As an example, the positive electrode active material for a sodium ion battery can include one or more of NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, 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 type materials, materials of the general formula X p M’ q (PO4) r O x Y 3-x . In the general formula X p M’ q (PO4) r O x Y 3-x , 0 < p < 4, 0 < q < 2, 1 < r < 3, 0 < x < 2, X includes H + , Li + , Na + , K+ and NH4 + 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.

[0139] In the embodiments of the present application, the modification compound of each of the above positive electrode active materials can be a doping modification and / or a surface coating modification, for example, a carbon coating modification, a fast ion conductor coating modification, etc.

[0140] The battery cell 7 will be accompanied by the deintercalation and consumption of active ions such as Li during the charging and discharging process, and the molar content of Li is different when the battery cell 7 is discharged to different states. In the enumeration of the positive electrode active material in the embodiments of the present application, the molar content of Li is the initial state of the material, i.e. the state before feeding, and the positive electrode active material is applied to the battery system. After charging and discharging cycles, the molar content of Li may change.

[0141] In the enumeration of the positive electrode active material in the embodiments of the present application, the molar content of oxygen O is only the theoretical state value, and the release of oxygen from the lattice will cause the molar content of oxygen O to change. In fact, the molar content of oxygen O will fluctuate.

[0142] In some embodiments, the positive electrode can use a foam metal. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, etc. When the foam metal is used as the positive electrode, the surface of the foam metal can not be provided with a positive electrode active material layer, of course, the positive electrode active material layer can also be provided. As an example, the foam metal can also be filled or / and deposited with a lithium source material, a potassium metal or a sodium metal, and the lithium source material is a lithium metal and / or a lithium-rich material.

[0143] In some embodiments, the positive electrode active material layer can also optionally include a positive electrode conductive agent. The type of positive electrode conductive agent is not particularly limited in the embodiments of the present application. 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 content of the positive electrode conductive agent in the positive electrode active material layer is ≤5wt%.

[0144] In some embodiments, the positive electrode active material layer can also optionally include a positive electrode binder. The present embodiments do not have particular limitations on the kind of positive electrode binder, and as an example, the positive electrode binder can include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate-based resin. In some embodiments, the mass percentage content of the positive electrode binder in the positive electrode active material layer is ≤ 5 wt%.

[0145] The positive electrode active material layer is typically formed by coating a positive electrode slurry on a positive electrode current collector, drying, and cold-pressing. The positive electrode slurry is typically formed by dispersing and uniformly stirring a positive electrode active material, an optional conductive agent, an optional binder, and any other components in a solvent. The solvent can be N-methylpyrrolidone (NMP), but is not limited thereto.

[0146] In some embodiments, the battery cell 7 is an ionic battery such as a lithium ion battery, and the negative electrode portion 14 can 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.

[0147] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction X thereof, and the negative electrode active material layer is disposed on either one or both of the two surfaces of the negative electrode current collector.

[0148] As an example, the negative electrode current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, a carbon, nickel, or titanium, or the like can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0149] As an example, the negative active material can employ a negative active material for a battery cell 7 known in the art. As an example, the negative active material can include one or more of: a carbon material (e.g., the carbon material includes one or more of artificial graphite, natural graphite, soft carbon, hard carbon), a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can include one or more of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can include one or more of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative active material layer for a battery can also be used. These negative active material layers can be used alone or in combination with two or more.

[0150] In some embodiments, the negative active material layer can also optionally include a negative conductive agent. The present embodiments do not have a particular limitation on the type of negative conductive agent, and as an example, the negative conductive agent can include one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. In some embodiments, the mass percentage content of the negative conductive agent in the negative active material layer is ≤ 5 wt%.

[0151] In some embodiments, the negative active material layer can also optionally include a negative binder. The present embodiments do not have a particular limitation on the type of negative binder, and as an example, the negative binder can include one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (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 content of the negative binder in the negative active material layer is ≤ 5 wt%.

[0152] In some embodiments, the negative active material layer can also optionally include other auxiliary agents. As an example, the other auxiliary agents can include a thickening agent, such as carboxymethyl cellulose sodium (CMC-Na), a PTC thermistor material, etc. In some embodiments, the mass percentage content of the other auxiliary agents in the negative active material layer is ≤ 2 wt%.

[0153] In some embodiments, the battery cell 7 also includes an electrolyte. During charging and discharging of the battery cell 7, active ions are inserted and extracted between the positive electrode sheet and the negative electrode sheet, and the electrolyte functions to conduct the active ions between the positive electrode sheet and the negative electrode sheet. The present embodiments do not have a particular limitation on the type of electrolyte, and the electrolyte can be selected as needed.

[0154] The electrolyte can include a solid-state electrolyte, for example, a solid-state electrolyte disposed in a form of a film layer between the positive electrode sheet and the negative electrode sheet. For example, the positive electrode sheet, the solid-state electrolyte layer 15, and the negative electrode sheet are stacked, and the solid-state electrolyte layer 15 can be coated on a surface of the positive active material layer in the positive electrode sheet or on a surface of the negative active material layer in the negative electrode sheet.

[0155] The electrolyte can include a solid-state electrolyte and an electrolytic solution. The electrolytic solution can employ a material known in the art.

[0156] In some embodiments, the solid-state electrolyte includes one or more of a sulfide solid-state electrolyte, an oxide solid-state electrolyte, a halide solid-state electrolyte, and a polymer solid-state electrolyte.

[0157] The sulfide solid-state electrolyte includes one or more of a sulfide crystalline solid-state electrolyte, a sulfide glass, and a glass-ceramic solid-state electrolyte.

[0158] In some embodiments, the sulfide solid-state electrolyte includes Li 10 GeP2S 12 , Li6PS5Cl, Li 10 SnP2S 12 , Li2S-P2S5, Li2S-SiS2, and Li2S-B2S3.

[0159] The oxide solid-state electrolyte includes two categories of oxide crystalline and oxide glassy (amorphous) according to the classification of material structure, wherein the oxide crystalline electrolyte includes one or more of perovskite type, NASICON type, LISICON type, and garnet type, and the oxide glassy oxide electrolyte is, for example, a LiPON type electrolyte.

[0160] In some embodiments, the oxide solid-state 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 .

[0161] In some embodiments, the halide solid-state electrolyte includes one or more of Li3YCl6, Li3ErCl6, Li3YBr6, Li3InBr6, Li3InCl6.

[0162] The polymer solid-state electrolyte (SPE) is mainly composed of a polymer matrix and an electrolyte salt. The electrolyte salt can include a lithium salt, which can include one or more of lithium hexafluorophosphate LiPF6, lithium perchlorate LiClO4, lithium hexafluoroarsenate LiAsF6, lithium tetrafluoroborate LiBF4. The electrolyte salt can include a sodium salt, which can include one or more of sodium hexafluorophosphate NaPF6, sodium perchlorate NaClO4, sodium hexafluoroarsenate NaAsF6, sodium tetrafluoroborate NaBF4.

[0163] In some embodiments, the SPE includes one or more of a polyepoxy, a polyesters, a polyalkoxy, a polyolefin, a polyacrylonitrile (PAN), a single-ion polymer electrolyte. For example, the polyepoxy includes one or more of polyethylene oxide (PEO), polypropylene oxide (PPO). The polyolefin includes one or more of polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC). The polyesters include one or more of polycarbonates, polymethyl methacrylate (PMMA). The polycarbonates include one or more of polypropylene carbonate, polytrimethylene carbonate.

[0164] Further, the polymer matrix can be inorganic particle hybridized, the inorganic particles including one or more of metal oxide nanoparticles such as MgO, Al2O3, SiO2, and zeolites, montmorillonite, etc. The addition of inorganic particles can reduce crystallinity, and the interaction between the polymer matrix, lithium salt, and inorganic particles can improve electrical conductivity and ion transference number. The inorganic particles can also play a role in adsorbing trace impurities such as moisture in the electrolyte and improving mechanical properties.

[0165] When the battery cell 7 of the embodiments of the present application is a lithium ion battery, as an example, the electrolyte salt in the electrolyte can include, but is not limited to, one or more of lithium hexafluorophosphate LiPF6, lithium tetrafluoroborate LiBF4, lithium perchlorate LiClO4, lithium hexafluoroarsenate LiAsF6, lithium bisfluorosulfonylimide LiFSI, lithium bis-trifluoromethanesulfonylimide LiTFSI, lithium trifluoromethanesulfonate LiTFS, lithium difluorobisoxalate borate LiDFOB, lithium bisoxalate borate LiBOB, lithium difluorophosphate LiPO2F2, lithium difluorodioxalate phosphate LiDFOP, and lithium tetrafluoroxalate phosphate LiTFOP.

[0166] When the battery cell 7 of the embodiments of the present application is a sodium-ion battery, as an example, the electrolyte salt in the electrolyte solution can include, but is not limited to, one or more of sodium hexafluorophosphate NaPF6, sodium tetrafluoroborate NaBF4, sodium perchlorate NaClO4, sodium hexafluoroarsenate NaAsF6, sodium bisfluorosulfonylimide NaFSI, sodium bis-trifluoromethanesulfonylimide NaTFSI, sodium trifluoromethanesulfonate NaTFS, sodium difluorobisoxalate borate NaDFOB, sodium bisoxalate borate NaBOB, sodium difluorophosphate NaPO2F2, sodium difluorobisoxalate phosphate NaDFOP, and sodium tetrafluorobisoxalate phosphate NaTFOP.

[0167] As an example, the solvent in the electrolyte solution can include, but is not limited to, one or more of ethylene carbonate EC, propylene carbonate PC, methyl ethyl carbonate EMC, diethyl carbonate DEC, dimethyl carbonate DMC, dipropyl carbonate DPC, methyl propyl carbonate MPC, ethyl propyl carbonate EPC, 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, cyclobutane sulfone SF, dimethyl sulfone MSM, methyl ethyl sulfone EMS, and diethyl sulfone ESE.

[0168] In the embodiments of the present application, the polymer matrix and the electrolyte salt can be added to a solvent such as N,N-dimethylformamide, uniformly dispersed to obtain a slurry, and then inverted mold forming is performed to obtain a polymer solid-state electrolyte.

[0169] In the embodiments of the present application, the electrode assembly 10 is in a wound structure or a stacked structure, and can be in a stacked structure.

[0170] When the electrode assembly 10 is in a wound structure, the positive electrode sheet is in a whole sheet structure, the negative electrode sheet is in a whole sheet structure, and the positive electrode sheet and the negative electrode sheet are wound in the same direction.

[0171] When the electrode assembly 10 is in a stacked structure, there are a plurality of positive electrode sheets and a plurality of negative electrode sheets, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are stacked.

[0172] As shown in FIGS. 6 and 7, in some embodiments, the battery cell 7 includes the first buffer assembly 30 and at least one electrode assembly 10, each electrode assembly 10 including the tab portion 11 connected to at least one side of the body portion 12 along the first direction Y and the body portion 12 including the positive electrode portion 13 containing a positive electrode active material, the solid-state electrolyte layer 15, and the negative electrode portion 14 containing a negative electrode active material, the positive electrode portion 13, the solid-state electrolyte layer 15, and the negative electrode portion 14 being stacked along the thickness direction X of the battery cell 7, and the first direction Y being perpendicular to the thickness direction X; the first buffer assembly 30 is disposed at least one side of the at least one electrode assembly 10 along the thickness direction X, and the projection of the body portion 12 along the thickness direction X is located within the projection of the first buffer assembly 30 along the thickness direction X.

[0173] The tab portion 11 can be disposed on one side or both sides of the body portion 12 along the first direction Y.

[0174] The first buffer assembly 30 is disposed at least one side of the at least one electrode assembly 10, and the projection of the 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.

[0175] As shown in FIG. 8, optionally, the first buffer assembly 30 is disposed on both sides of the at least one electrode assembly 10.

[0176] The first buffer assembly 30 is disposed opposite to the large face of the battery cell 7, and can effectively buffer and protect the large face of the battery cell 7. In the embodiments of the present application, the large face of the battery cell 7 refers to the face with a relatively large area of the battery cell 7, for example, the electrode assembly 10 has a cuboid structure, and the electrode assembly 10 can include four side faces and two main faces, the area of the main face is larger than that of the side face, the main face is perpendicular to the thickness direction X, and the main face is subjected to more significant stress. By disposing the first buffer assembly 30 opposite to the large face, the large face 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 in the battery cell 7, reducing the risk of breakage and powdering of the electrode tab, reducing the risk of positive and negative electrode contact short circuit, and improving the structural stability and use reliability of the battery cell 7.

[0177] Moreover, it can also reduce the problems of large self-discharge and capacity loss of the battery cell 7, and further improve the electrical performance of the battery cell 7, such as improving the cycle performance and discharge rate performance of the battery cell 7.

[0178] As shown in FIGS. 8-10, in some embodiments, the first buffer assembly 30 extends beyond the electrode assembly 10 in the second direction Z, specifically, the first buffer assembly 30 extends beyond the main body portion 12 in the second direction Z. The first buffer assembly 30 can effectively protect the electrode assembly 10, and improve the structural stability of the battery cell 7. Of course, the size of the first buffer assembly 30 in the second direction Z can also be the same as the size of the electrode assembly 10 in the second direction Z, or the size of the first buffer assembly 30 in the second direction Z can also be the same as the size of the main body portion 12 in the second direction Z, and the projections of the two in the thickness direction X coincide.

[0179] Since the risk of damage to the electrode assembly 10 in the battery cell 7 is relatively large, the first buffer assembly 30 can effectively protect the electrode assembly 10, thereby improving the structural stability of the battery cell 7; further, the projection of the first buffer assembly 30 in the thickness direction X is located within the projection of the main body portion 12 in the thickness direction X, which can reduce the space occupancy of the first buffer assembly 30 and improve the space occupancy of the electrode assembly 10. For example, the size of the first buffer assembly 30 in the second direction Z is less than or equal to the size of the main body portion 12 in the second direction Z.

[0180] In some embodiments, the tab portion 11 of the battery cell 7 is connected to at least one side of the main body portion 12 in the first direction Y, for example, on one side or both sides, and the first direction Y, the second direction Z and the thickness direction X are perpendicular to each other; the first buffer assembly 30 also extends to the connection between the main body portion 12 and the tab portion 11 of the battery cell 7, effectively protecting the connection and reducing the risk of the tab portion 11 breaking from the connection.

[0181] Further, the first buffer assembly 30 also covers the part of the tab portion 11 of the battery cell 7 close to the main body portion 12; further, the size of the part of the tab portion 11 close to the main body portion 12 in the first direction Y is L1, and the size of the tab portion 11 in the first direction Y is L2, 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 a range composed of any two of the above values. The first buffer assembly 30 covers the L1 part, which can effectively protect the connection area between the tab portion 11 and the main body portion 12, and provide space for the assembly of the tab portion 11 and external components.

[0182] In some embodiments, the first buffer assembly 30 has a dimension H1 along the thickness direction X, the electrode assembly 10 has a dimension H2 along the thickness direction X, 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 a range defined by any two of the above values. When the thickness of the first buffer assembly 30 is within the above range, the first buffer assembly 30 can effectively play a buffering and protecting role, and does not occupy too much space, thereby being able to balance the appropriate energy density. In FIG. 8, H1 represents the dimension of the first buffer assembly 30 along the thickness direction X, i.e., the thickness of the first buffer assembly 30, and H2 represents the dimension of the electrode assembly 10 along the thickness direction X, i.e., the thickness of the electrode assembly 10.

[0183] In some embodiments, the first buffer assembly 30 can have a layered structure, for example, a single-layer structure or a multi-layer composite structure. Of course, the first buffer assembly 30 can also have other structure types, for example, a frame structure, etc. The layered structure covers the electrode assembly 10 and can more effectively play a buffering and protecting role for the battery cell 7.

[0184] One or more hole structures can be provided in the layered structure, and the holes can or can not penetrate the layered structure along the thickness direction X. Through the provision of the hole structure, the layered structure can present a mesh shape, etc. The provision of the hole structure makes the layered structure lighter in weight, which is beneficial to improving the weight energy density of the battery cell 7. Of course, the layered structure can also be a solid structure, i.e., it basically does not include a macroscopic hole structure. However, due to the characteristics of the material itself, the layered structure can include a micro-hole structure, etc.

[0185] In some embodiments, the first buffer assembly 30 can be arranged on the surface of the electrode assembly 10, and the first buffer assembly 30 and the electrode assembly 10 are in contact, and there can be no bonding force between them.

[0186] In other embodiments, the first buffer assembly 30 can be arranged on the surface of the electrode assembly 10, and the bonding force between the first buffer assembly 30 and the electrode assembly 10 is strong, and the first buffer assembly 30 is not prone to position movement. In the charging and discharging process of the battery cell 7, the first buffer assembly 30 can effectively play a buffering and protecting role.

[0187] Optionally, the peeling strength between the first buffer assembly 30 and the electrode assembly 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 a range defined by any two of the above values. When the peeling strength is within the above range, the bonding force between the first buffer assembly 30 and the surface of the electrode assembly 10 is strong, and the first buffer assembly 30 is not prone to falling off from the electrode assembly 10.

[0188] In some embodiments, the first buffer assembly 30 has an elastic modulus of 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 a range defined by any two of the above values. When the first buffer assembly 30 has an elastic modulus in the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external actions of the battery cell 7.

[0189] In some embodiments, the first buffer assembly 30 has a Poisson's ratio of 0.2 to 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 a range defined by any two of the above values. When the first buffer assembly 30 has a Poisson's ratio in the above range, it has excellent elastic deformation capability and can effectively buffer stress problems caused by internal and external actions of the battery cell 7.

[0190] In some embodiments, the first buffer assembly 30 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.

[0191] Illustratively, the polyolefin-based polymer includes one or more of cis-1,4-polyisoprene, cis-1,4-polybutadiene, polychloroprene, and ethylene-propylene terpolymer.

[0192] Illustratively, the organosiloxane-based polymer includes one or more of polymethylvinylsiloxane PMVS, polymethylphenylvinylsiloxane, and polyfluorosiloxane.

[0193] The above materials can exist in the form of a rubber pad, for example, cis-1,4-polyisoprene rubber, etc.

[0194] In some embodiments, the negative electrode portion 14 is projected in the thickness direction X within the projection of the solid-state electrolyte layer 15 in the thickness direction X, and the projection of the solid-state electrolyte layer 15 in the thickness direction X is within the projection of the first buffer assembly 30 in the thickness direction X. The first buffer assembly 10 can effectively buffer and protect the main body portion structure of the electrode assembly 10.

[0195] In some embodiments, the battery cell 7 further comprises a housing 20, which houses the electrode assembly 10 and the first buffer assembly 30.

[0196] As an embodiment of the present application, the battery cell 7 comprises the first buffer assembly 30 and the electrode assembly 10, each of the electrode assembly 10 comprises a main body portion 12 and a tab portion 11 connected to a side of the main body portion 12 along a first direction Y, the main body portion 12 comprises 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-state electrolyte layer 15, the positive electrode portion 13, the solid-state electrolyte layer 15, and the negative electrode portion 14 are stacked along a thickness direction X of the battery cell 7, the first direction Y is perpendicular to the thickness direction X; the first buffer assembly 30 is arranged on both sides of the electrode assembly 10 along the thickness direction X, a projection of the main body portion 12 along the thickness direction X is located within a 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 a second direction Z, the second direction Z, the first direction Y, and the thickness direction X are perpendicular to each other.

[0197] Embodiments

[0198] The embodiments described below are merely illustrative of the present application and do not limit the scope of the present application. Unless otherwise stated, all parts, percentages, and ratios reported herein are based on mass, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and used directly without further purification, and the instruments used in the embodiments are commercially available.

[0199] Embodiment 1

[0200] The battery cell comprises an electrode assembly and a first buffer assembly, the electrode assembly comprises a main body portion and a tab portion connected to a side of the main body portion along a first direction, the main body portion comprises a positive electrode portion containing a positive electrode active material, a negative electrode portion containing a negative electrode active material, and a solid-state electrolyte layer, the positive electrode portion, the solid-state electrolyte layer, and the negative electrode portion are stacked along a thickness direction of the battery cell, the first direction is perpendicular to the thickness direction; the first buffer assembly is arranged on both sides of the electrode assembly along the thickness direction, a projection of the main body portion along the thickness direction is located within a projection of the first buffer assembly along the thickness direction.

[0201] Embodiments 2-1 to 2-3

[0202] The battery cell is prepared by a method similar to that of Embodiment 1, except that the material of the first buffer assembly is adjusted.

[0203] Embodiments 3-1 and 3-2

[0204] A battery cell was prepared in a similar manner to Example 1, except that the thickness of the first buffer assembly was adjusted.

[0205] Example 4

[0206] A battery cell was prepared in a similar manner to Example 1, except that the value of L1 / L2 was adjusted.

[0207] Comparative Example 1

[0208] The battery cell comprises an electrode assembly, the electrode assembly comprises a main body part and a tab part connected to 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 cell, and the first direction is perpendicular to the thickness direction.

[0209] Performance test

[0210] In the present application, the electrical performance of the battery cell can be detected by using instruments and methods known in the art, for example, according to GB / T 31486-2015 Electrical performance requirements and test methods for power storage batteries for electric vehicles, GB / T 31484-2015 Cycle life requirements and test methods for power storage batteries for electric vehicles.

[0211] Specifically, the cycle life can be tested by the following method: at 25°C, the battery cells prepared in the examples and comparative examples are subjected to the following cycle test:

[0212] 1) stand for 30 min;

[0213] 2) charge at 0.33C rate to the upper limit voltage of the cut-off;

[0214] 3) stand for 30 min;

[0215] 4) discharge at 0.33C rate to the cut-off voltage;

[0216] 5) stand for 30 min;

[0217] 6) cycle 2) to 5) until the capacity of the battery cell decays to 80% of the initial capacity, and record the cycle number.

[0218] The cycle number of Comparative Example 1 is equivalent to 1, and the relative cycle number of other examples is calculated based on the cycle number of Comparative Example 1; for example, if the cycle number of Comparative Example 1 is 500 cycles and the cycle number of Example 1 is 625 cycles, then in the table, the cycle of Comparative Example 1 is 1 and the cycle of Example 1 is 625 / 500 = 1.25.

[0219] The discharge rate can be tested by the following method:

[0220] At 25℃, the battery cells prepared in the examples and comparative examples were charged to the upper limit voltage of the charge cut-off at a rate of 1C, discharged to the lower limit voltage of the discharge cut-off at a rate of 1C, and the discharge capacity was calculated. The discharge capacity of Comparative Example 1 was taken as 1, and the relative discharge capacity of other examples was calculated based on the discharge capacity of Comparative Example 1.

[0221] Test results

[0222] The test results are shown in Table 1.

[0223] Table 1

[0224] As can be seen from Table 1,

[0225] Compared with Comparative Example 1, the first buffer assembly of polyurethane used in Example 1 can effectively improve the use reliability of the battery cell, and can further improve the electrical performance of the battery cell, for example, the cycle performance can be improved by 25%, and the discharge rate performance can be improved by 20%;

[0226] The first buffer assembly of different materials can basically improve the electrical performance of the battery cell, but the protection effect of different materials on the battery cell is not consistent, and there are differences in electrical performance, and the degree of influence on the electrical performance is ranked as follows: polyethylene terephthalate > polyurethane > silicone rubber > polyimide;

[0227] The thickness of the first buffer assembly has an effect on the electrical performance of the battery cell, the thicker the first buffer assembly, the better the electrical performance of the battery cell, but it is not conducive to the improvement of the energy density;

[0228] The longer the length of the first buffer assembly covering the tab part, the more conducive to reducing the risk of tab part breakage and improving the use reliability of the battery cell; but it is not conducive to the improvement of the energy density of the battery cell and the assembly of the tab part and other parts; in general, when L1 / L2 is greater than 0 and less than or equal to 0.5, it is conducive to the comprehensive improvement of the use reliability of the battery cell and the like.

[0229] Although the illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments cannot be interpreted as a limitation on the implementation of the present application, and the embodiments can be changed, replaced and modified 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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