Battery cell, battery device and electric device

Abstract

The utility model discloses a battery monomer, battery device and electricity utilization device, the battery monomer includes: shell subassembly, battery cell subassembly, insulating film and buffer layer, the shell subassembly has the accommodation cavity, battery cell subassembly is provided in the accommodation cavity, and battery cell subassembly includes battery cell body, battery cell body includes multilayer anode pole piece layer and multilayer cathode pole piece layer, and the buffer layer is located in the battery cell body. The buffer layer is arranged in the containing cavity and comprises at least one first buffer part and at least one second buffer part, the first buffer part extends in a long strip shape in the first direction, the second buffer part extends in a long strip shape in the second direction, and the first buffer part and the second buffer part are arranged in an intersecting mode; the first direction and the second direction are both perpendicular to the thickness direction of the shell assembly. Therefore, the buffer layer can be used for supporting the battery cell assembly, and the buffer layer can provide certain resistance for the expansion of the battery cell body, so that the pole piece is not easy to wrinkle.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, battery devices, as the power source, play an irreplaceable and crucial role. During use, individual battery cells require continuous charging and discharging, which can easily lead to expansion and deformation of the cell itself, resulting in wrinkling of the electrode plates and affecting the lifespan of the battery cell. Utility Model Content

[0003] This application proposes a battery cell, a battery device, and an electrical device. The buffer layer can be used to support the battery cell body and can provide a certain resistance to the expansion of the battery cell body, so that the electrode sheets are less likely to wrinkle.

[0004] In a first aspect, embodiments of this application provide a battery cell, comprising: a housing assembly, a cell assembly, an insulating film, and a buffer layer. The housing assembly has a receiving cavity, the cell assembly is disposed in the receiving cavity, and the cell assembly includes a cell body, the cell body including multiple anode electrode layers and multiple cathode electrode layers, the multiple anode electrode layers and multiple cathode electrode layers being alternately arranged along the thickness direction of the housing assembly, the insulating film being disposed in the receiving cavity and covering the cell body, and the buffer layer being disposed in the receiving cavity, the buffer layer including at least one first buffer portion and at least one second buffer portion, the first buffer portion extending in a first direction as an elongated strip, the second buffer portion extending in a second direction as an elongated strip, the first buffer portion and the second buffer portion being intersecting, the first direction and the second direction being perpendicular to the thickness direction of the housing assembly, wherein, in the thickness direction of the housing assembly, buffer layers are respectively sandwiched between opposite sides of the cell body and the insulating film; and / or, in the thickness direction of the housing assembly, buffer layers are respectively sandwiched between opposite sides of the insulating film and the housing assembly.

[0005] In the above technical solution, both the cell body and the buffer layer are located in the receiving cavity. The buffer layer can be used to support the cell body. When the battery cell is continuously charged and discharged, the cell body is prone to expansion and deformation. The buffer layer can provide a certain resistance to the expansion of the cell body, that is, the buffer layer can provide a binding force for the cell, so that the electrode is less likely to wrinkle, thereby reducing the possibility of lithium plating in the battery cell and improving the service life of the battery cell. Moreover, the buffer layer includes a first buffer part and a second buffer part that are intersected. The first buffer part and the second buffer part do not overlap in at least part of their area, so that the support range of the first buffer part and the second buffer part is larger, making it less likely to cause uneven stress on the cell body and improving the reliability of the battery cell.

[0006] In some embodiments, there are multiple first buffer portions and multiple second buffer portions, with multiple first buffer portions spaced apart along a second direction and multiple second buffer portions spaced apart along a first direction. Each first buffer portion intersects with all second buffer portions, and each second buffer portion intersects with all first buffer portions. The first direction is the height direction of the housing assembly, and the second direction is the length direction of the housing assembly.

[0007] In the above technical solution, multiple first buffer sections and multiple second buffer sections can increase the support area of ​​the buffer layer, so as to improve the binding force of the buffer layer on the battery cell body. Each first buffer section intersects with all second buffer sections, and each second buffer section intersects with all first buffer sections, so that the multiple first buffer sections and multiple second buffer sections can be approximately configured as a mesh structure, so that the force on the buffer layer can be better dispersed, which is beneficial to improving the service life of the buffer layer.

[0008] In some embodiments, two first buffer portions and two second buffer portions are connected end to end to form a square ring structure.

[0009] In the above technical solution, the two first buffer parts and the two second buffer parts are connected end to end to form a quadrilateral, so as to simplify the structure of the buffer layer and facilitate its processing and manufacturing.

[0010] In some embodiments, the width of the first buffer portion in the second direction is t1, and the width of the second buffer portion in the first direction is t2, where 20mm≤t1≤60mm and 20mm≤t2≤60mm.

[0011] In the above technical solution, by setting the width of the first buffer part in the second direction and the width of the second buffer part in the first direction to be within the range of 20mm to 60mm, both the first buffer part and the second buffer part have sufficient area to support the cell body, which helps to reduce the problem of electrode wrinkling during the charging and discharging process of the battery cell.

[0012] In some embodiments, one of the housing assembly, the cell assembly, and the insulating film is bonded to the buffer layer.

[0013] In the above technical solution, the buffer layer can be bonded and fixed to one of the housing assembly, cell assembly and insulating film, so as to simplify the assembly of the buffer layer and facilitate the improvement of the assembly efficiency of the battery cell.

[0014] In some embodiments, the housing assembly includes a housing body and a housing cover. The housing body is open at one end in the height direction of the housing assembly, and the housing cover is disposed on the open end of the housing body to define a receiving cavity. The cell assembly also includes a conductive portion that connects the cell body and the terminal post of the battery cell. In the height direction of the housing assembly, the center of the buffer layer is offset from the center of the housing body in a direction away from the conductive portion. The battery cell is configured to satisfy at least one of the following conditions A1 to A4. In condition A1, the dimension of the housing body in the height direction of the housing assembly is L1, and the dimension of the buffer layer in the height direction of the housing assembly is L1. The dimension of the upper part is L2, 0.9≤L2 / L1≤0.98; In condition A2, the dimension of the cell body in the height direction of the housing assembly is L3, and the dimension of the buffer layer in the height direction of the housing assembly is L2, 1.02≤L2 / L3≤1.1; In condition A3, the distance between the end of the buffer layer facing the housing cover and the housing cover is t3, 1mm≤t3≤3mm; In condition A4, the length of the housing assembly is greater than the thickness of the housing assembly, and in the length direction of the housing assembly, the distance between the buffer layer and the housing body is t4, 5mm≤t4≤15mm.

[0015] In the above technical solution, in condition A1, by setting the ratio of the height dimension of the buffer layer to the height dimension of the casing in the height direction within the range of 0.9 to 0.98, and by setting the center of the buffer layer away from the center of the casing in the direction away from the conductive part, the buffer layer has sufficient dimensions in the height direction to support the cell body. Simultaneously, the buffer layer does not easily affect the electrical connection between the conductive part and the terminal, thus improving the stability of the battery cell operation. In condition A2, by setting the ratio of the height dimension of the buffer layer to the height dimension of the cell body in the height direction within the range of 1.02 to 1.1, the buffer layer has sufficient dimensions in the height direction to support the cell body. The buffer layer supports the battery cell body and does not easily affect the electrical connection between the conductive part and the terminal, thus improving the stability of the battery cell operation. In condition A3, by setting the distance between the end of the buffer layer facing the cover and the cover in the range of 1mm to 3mm, a certain gap exists between the buffer layer and the cover, which does not easily affect the electrical connection between the conductive part and the terminal. In condition A4, in the length direction of the housing assembly, by setting the distance between the buffer layer and the housing body in the range of 5mm to 15mm, that is, the size of the buffer layer in the length direction is smaller than the size of the housing body in the length direction, more space is provided for the assembly of the buffer layer, which facilitates the assembly of the buffer layer.

[0016] In some embodiments, the buffer layer is a polymer layer capable of absorbing liquid and swelling, and the polymer layer is configured to satisfy at least one of the following conditions B1 to B3: In condition B1, the thickness of the polymer layer in the thickness direction of the housing assembly is d1, and the distance between the two inner wall surfaces of the housing assembly disposed opposite each other in the thickness direction is d2, where d1 = 0.002 * d2; In condition B2, the thickness of the polymer layer in the thickness direction of the housing assembly is d1, where 20 μm ≤ d1 ≤ 100 μm; In condition B3, the swelling thickness growth coefficient of the polymer layer is m, where 8 ≤ m ≤ 20.

[0017] In the above technical solution, in condition B1, the ratio of the thickness of the polymer layer to the distance between the two inner wall surfaces of the housing assembly in the thickness direction is 0.002, so that the thickness of the polymer layer in the cavity is more suitable, the polymer layer can provide a more stable binding force, and it is convenient to improve the applicability of the buffer layer; in condition B2, by setting the thickness of the polymer layer in the range of 20μm to 100μm, the polymer layer can better support the cell body after expansion, so that the binding force provided by the polymer layer on the cell body is more reasonable; in condition B3, by setting the swelling thickness growth coefficient of the polymer layer in the range of 8 to 20, the assembly of the polymer layer is more convenient, and the binding force provided by the polymer layer on the cell body is more reasonable.

[0018] In some embodiments, the cell body is a wound structure, and the peripheral wall of the cell body includes a flat area and an arcuate area connecting the flat area. The two arcuate areas are arranged opposite to each other along the length direction of the housing assembly, and the buffer layer is opposite to the flat area and offset from the arcuate area; or, the cell body is a stacked structure.

[0019] In the above technical solution, the cell body is a wound structure, the buffer layer is opposite to the flat area and the buffer layer is staggered from the arc area, so that the buffer layer is less likely to affect the gap of some electrode sheets in the arc area, reducing the possibility of the buffer layer causing the electrode interface to deteriorate in the arc area; the cell body is a stacked structure, and the buffer layer can be set opposite to the large surface of the cell body, making the setting position of the buffer layer more flexible.

[0020] In some embodiments, the buffer layer has a dimension of L4 in the length direction of the housing assembly, and the distance between the two inner wall surfaces of the housing assembly disposed opposite each other in the length direction is L5, where 0.85≤L4 / L5≤0.95.

[0021] In the above technical solution, by setting the ratio of the length dimension of the buffer layer to the distance between the two inner wall surfaces of the housing assembly that are arranged opposite each other in the length direction to a range of 0.85 to 0.95, the buffer layer can have sufficient length, provide suitable binding force for the cell body, and at the same time, the buffer layer is less likely to affect the gap of some electrode sheets in the arc area.

[0022] In some embodiments, there are multiple battery cell bodies arranged sequentially along the thickness direction of the housing assembly, an insulating film covers all battery cell bodies, and each of the multiple battery cell bodies has a buffer layer on its outermost side in the thickness direction of the housing assembly.

[0023] In the above technical solution, the buffer layer is located on the outermost side of the multiple cell bodies in the thickness direction of the housing assembly, so as to simplify the assembly of the buffer layer and the multiple cell bodies and facilitate the improvement of the assembly efficiency of the battery cells.

[0024] In some embodiments, a buffer layer is provided between two adjacent battery cell bodies.

[0025] In the above technical solution, the buffer layer can separate two adjacent cell bodies so that the two adjacent cell bodies are not likely to come into direct contact. When the two adjacent cell bodies expand, the buffer layer can provide a binding force, reducing the risk of electrode wrinkling.

[0026] In some embodiments, the peripheral wall of the battery cell body is a cylindrical surface, and a buffer layer is sleeved on the outside of the battery cell body.

[0027] In the above technical solution, the buffer layer is sleeved outside the cell body to make the assembly of the buffer layer simpler and facilitate the improvement of the assembly efficiency of the battery cell.

[0028] Secondly, embodiments of this application provide a battery device including a battery cell as described in the first aspect.

[0029] In the above technical solution, since the battery cell has a good service life, using the battery cell can improve the service life of the battery device.

[0030] Thirdly, embodiments of this application provide an electrical device, including a battery cell as described in the first aspect or a battery device as described in the second aspect.

[0031] In the above technical solution, since both the battery cell and the battery device have a good service life, using the battery cell or battery device can improve the service life of the electrical device. Attached Figure Description

[0032] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0033] Figure 1 The electrical device provided in some embodiments of this application is a structural schematic diagram of a vehicle;

[0034] Figure 2 Exploded views of the structure of the battery device provided in some embodiments of this application;

[0035] Figure 3A schematic diagram of a battery cell provided in some embodiments of this application;

[0036] Figure 4 This is a schematic diagram of the assembly of the insulating film and buffer layer provided in some embodiments of this application;

[0037] Figure 5 Exploded views of a single battery cell provided in some embodiments of this application;

[0038] Figure 6 This application provides assembly diagrams of the housing assembly and buffer layer for some embodiments;

[0039] Figure 7 for Figure 6 A cross-sectional view of the housing assembly and buffer layer shown;

[0040] Figure 8 A schematic diagram of a battery cell provided in some embodiments of this application;

[0041] Figure 9 A schematic diagram of a battery cell provided in some embodiments of this application;

[0042] Figure 10 A schematic diagram of a battery cell provided in some embodiments of this application;

[0043] Figure 11 for Figure 3 Another schematic diagram of the battery cell shown;

[0044] Figure 12 for Figure 3 Another schematic diagram of a single battery cell is shown.

[0045] Reference numerals: 100 for individual battery cell, 200 for battery assembly, 300 for electrical device.

[0046] 10 housing assembly, 12 receiving cavity, 14 housing body, 16 housing cover

[0047] Battery cell assembly 20, battery cell body 22, anode electrode layer 22a, cathode electrode layer 22b, flat region 22c, arc-shaped region 22d, conductive part 24.

[0048] Insulating film 30

[0049] Buffer layer 40, first buffer section 41, second buffer section 42

[0050] pole 50,

[0051] Box 60, Receiving cavity 62, First box 64, Second box 66,

[0052] Controller 72, Motor 74. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0055] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0057] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0058] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of the various components shown in the accompanying drawings in the embodiments of this application are merely illustrative and should not constitute any limitation on this application.

[0059] In this application, "multiple" means two or more (including two).

[0060] In this application, the battery cell may include lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited thereto.

[0061] The battery apparatus mentioned in the embodiments of this application can refer to an assembly of one or more battery cells for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar. In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0062] As an example, a battery cell assembly can be a battery module, which consists of multiple battery cells arranged and fixed together to form a single module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0063] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing. As an example, the individual battery cell assembly may be a battery pack, which can be housed within the housing by securing the battery pack to the housing. Alternatively, the individual battery cell assembly may be housed within the housing by directly securing multiple individual battery cells to the housing. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the individual battery cells.

[0064] A single battery cell comprises a casing assembly, a cell assembly, and an electrolyte. The casing assembly houses the cell assembly and electrolyte. The cell assembly consists of an anode electrode layer, a cathode electrode layer, and a separator. The casing assembly can be made of aluminum, but is not limited to this. The battery cell primarily functions by the movement of metal ions between the anode and cathode electrode layers. The anode electrode layer includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector material can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The cathode electrode layer includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector without the negative active material layer protrudes from the one coated with the negative active material layer, and the negative current collector without the negative active material layer serves as the negative electrode tab. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. To ensure that a large current can be passed without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together.

[0065] The separator can be made of PP (polypropylene) or PE (polyethylene), etc. Furthermore, the electrode assembly can be a wound structure or a stacked structure; the embodiments of this application are not limited to these.

[0066] In recent years, new energy vehicles have made leaps and bounds in development. In the field of electric vehicles, battery devices play an irreplaceable and important role as the power source of electric vehicles.

[0067] During use, battery cells undergo continuous charging and discharging, which can easily lead to expansion and deformation of the cell body, resulting in wrinkling of the electrode plates and affecting the lifespan of the battery cell. Related technologies utilize either symmetrical or asymmetrical housing assemblies for the battery cell, employing uneven thickness designs on the top and main surfaces to enhance the strength of the welds between the housing and the cover, and to secure the cell assembly. However, current asymmetrical housing assemblies only address the issue of weld cracking due to breathing fatigue in the later stages of charge-discharge cycles; they do not solve the problem of electrode wrinkling during cycle operation.

[0068] Based on the above considerations, in order to solve the problem of electrode wrinkling during the charging and discharging process of a battery cell, this application designs a battery cell, including: a housing assembly, a cell assembly, an insulating film, and a buffer layer. The housing assembly has a receiving cavity, the cell assembly is disposed in the receiving cavity, and the cell assembly includes a cell body, the cell body includes multiple anode electrode layers and multiple cathode electrode layers, the multiple anode electrode layers and multiple cathode electrode layers are alternately arranged along the thickness direction of the housing assembly, the insulating film is disposed in the receiving cavity and covers the cell body, the buffer layer is disposed in the receiving cavity, and the buffer layer includes at least one first buffer portion and at least one second buffer portion. The first buffer portion extends into an elongated shape along a first direction, and the second buffer portion extends into an elongated shape along a second direction. The first buffer portion and the second buffer portion are intersecting. Both the first direction and the second direction are perpendicular to the thickness direction of the housing assembly. In the thickness direction of the housing assembly, a buffer layer is sandwiched between the cell body and the insulating film; and / or, in the thickness direction of the housing assembly, a buffer layer is sandwiched between the insulating film and the housing assembly.

[0069] In the above technical solution, both the cell body and the buffer layer are located in the receiving cavity. The buffer layer can be used to support the cell body. When the battery cell is continuously charged and discharged, the cell body is prone to expansion and deformation. The buffer layer can provide a certain resistance to the expansion of the cell body, that is, the buffer layer can provide a binding force for the cell, so that the electrode is less likely to wrinkle, thereby reducing the possibility of lithium plating in the battery cell and improving the service life of the battery cell. Moreover, the buffer layer includes a first buffer part and a second buffer part that are intersected. The first buffer part and the second buffer part do not overlap in at least part of their area, so that the support range of the first buffer part and the second buffer part is larger, making it less likely to cause uneven stress on the cell body and improving the reliability of the battery cell.

[0070] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system incorporating the battery device disclosed in this application can be used to construct such an electrical device.

[0071] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0072] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device 300 according to an embodiment of this application.

[0073] Please refer to Figure 1 , Figure 1 The electrical device 300 provided in some embodiments of this application is a schematic diagram of a vehicle structure. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 200 is installed inside the vehicle, and the battery device 200 can be located at the bottom, front, or rear of the vehicle. The battery device 200 can be used to power the vehicle; for example, the battery device 200 can serve as the vehicle's operating power source. The vehicle may also include a controller 72 and a motor 74. The controller 72 is used to control the battery device 200 to supply power to the motor 74, for example, to meet the power needs of the vehicle during starting, navigation, and driving.

[0074] In some embodiments of this application, the battery device 200 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0075] Please refer to Figure 2 , Figure 2 This is an exploded view of the structure of a battery device 200 provided in some embodiments of this application. The battery device 200 includes a housing 60 and a plurality of battery cells 100, which are housed within the housing 60. The housing 60 provides assembly space for the battery cells 100 and can adopt various structures. In some embodiments, the housing 60 may include a first housing 64 and a second housing 66, which overlap each other, and together define a receiving cavity 62 for accommodating the battery cells 100. The second housing 66 may be a hollow structure open at one end, and the first housing 64 may be a plate-like structure, with the first housing 64 covering the open side of the second housing 66 so that the first housing 64 and the second housing 66 together define the receiving cavity 62; alternatively, the first housing 64 and the second housing 66 may both be hollow structures open on one side, with the open side of the first housing 64 covering the open side of the second housing 66. Of course, the box 60 formed by the first box 64 and the second box 66 can be of various shapes, such as a cylinder, a cuboid, etc.

[0076] In the battery device 200, multiple battery cells 100 can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 100 are connected in both series and parallel configurations. Multiple battery cells 100 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 100 is housed within the housing 60. Alternatively, the battery device 200 can also consist of multiple battery cells 100 first connected in series, parallel, or in a mixed configuration to form a battery cell assembly, and then these battery cell assemblies are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 60. The battery device 200 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 100.

[0077] Please refer to Figure 2 , Figure 2 The following is an exploded view of the structure of a battery device 200 provided in some embodiments of this application. The battery device 200 includes multiple rows of battery cells arranged along the length of a housing 60, with each row including multiple battery cells 100 arranged along the width of the housing 60; or, the multiple rows of battery cells are arranged along the width of the housing 60, with each row including multiple battery cells 100 arranged along the length of the housing 60.

[0078] Each battery cell 100 can be a secondary battery or a primary battery. A secondary battery refers to a battery cell 100 that can be recharged after discharge to activate its active materials and continue to be used. It can also be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited in this regard. The battery cell 100 can be cylindrical, flat, cuboid, or other shapes. For example, in... Figure 2 In the middle, the shape of the battery cell 100 is a cuboid.

[0079] Please refer to Figure 3In the embodiments of this application, the battery cell 100 includes: a housing assembly 10, a cell assembly 20, an insulating film 30, and a buffer layer 40. The housing assembly 10 has a receiving cavity 12. The cell assembly 20 is disposed in the receiving cavity 12, and the cell assembly 20 includes a cell body 22. The cell body 22 includes multiple anode electrode layers 22a and multiple cathode electrode layers 22b. The multiple anode electrode layers 22a and multiple cathode electrode layers 22b are alternately arranged along the thickness direction of the housing assembly 10. The insulating film 30 is disposed in the receiving cavity 12 and covers the cell body 22. The buffer layer 40 is disposed in the receiving cavity 12. For example, the cell body 22 has a stacked structure, which includes multiple anode plates and multiple cathode plates. A single anode plate can be formed as an anode plate layer 22a, and a single cathode plate can be formed as a cathode plate layer 22b. Another example is that the cell body 22 has a wound structure, which includes anode plates and cathode plates. The anode plates are wound to form multiple anode plate layers 22a, and the cathode plates are wound to form multiple cathode plate layers 22b.

[0080] In this configuration, buffer layers 40 are respectively sandwiched between opposite sides of the battery cell body 22 and the insulating film 30 in the thickness direction of the housing assembly 10. For example, if there is only one battery cell body 22, the buffer layer 40 is fixed on opposite sides of the battery cell body 22 in the thickness direction of the housing assembly 10, or the buffer layer 40 is fixed on opposite sides of the insulating film 30 in the thickness direction of the housing assembly 10 and the buffer layer 40 is located on the side of the insulating film 40 facing the battery cell body 22 (e.g., ...). Figure 3 (as shown); and / or, in the thickness direction of the housing assembly 10, buffer layers 40 are respectively sandwiched between opposite sides of the insulating film 30 and the housing assembly 10, for example, the buffer layers 40 are assembled on opposite sides of the insulating film 30 in the thickness direction of the housing assembly 10 and the buffer layers 40 are located on the side of the insulating film 30 facing the housing assembly 10 (e.g. Figure 4 As shown, the buffer layer 40 is disposed on the side of the insulating film 30 facing away from the cell body 22, or the buffer layer 40 is fixed to the inner wall surfaces of opposite sides of the housing assembly 10 in the thickness direction (e.g., Figure 6 (As shown).

[0081] As can be seen, both the cell body 22 and the buffer layer 40 are located within the receiving cavity 12. The buffer layer 40 can be used to support the cell body 22, making its position more stable. During continuous charging and discharging of the battery cell 100, the cell body 22 is prone to expansion and deformation. The buffer layer 40 can reduce the gap between the outer periphery of the cell body 22 and other components. The buffer layer 40 can provide a certain resistance to the expansion of the cell body 22, that is, it can provide a binding force to the cell body 22, thus improving the wrinkling phenomenon caused by insufficient binding of the outermost electrode layers of the cell body 22. For example, the outermost anode electrode layer 22a or cathode electrode layer 22b of the cell body 22 is less prone to wrinkling, thereby reducing the possibility of lithium plating problems in the battery cell 100, reducing the risk of water pressure drops, and improving the reliability and service life of the battery cell 100. Moreover, the buffer layer 40 has various different installation positions, making its assembly more flexible and adaptable to different installation situations.

[0082] For example, for a single buffer layer 40, when the buffer layer 40 is fixed to one side of the cell body 22 in the thickness direction of the housing assembly 10, the buffer layer 40 can be assembled to the outside of the cell body 22 in the external environment first, then the insulating film 30 can be wrapped around the buffer layer 40 and the cell body 22, and finally the insulating film 30, the buffer layer 40 and the cell body 22 can be installed together into the receiving cavity 12; when the buffer layer 40 is fixed to the side of the insulating film 30 facing the cell body 22 (the buffer layer 40 is fixed to the inner surface of the insulating film 30), the buffer layer 40 can be assembled to the side of the insulating film 30 facing the cell body 22 in the external environment first, and then the insulating film 30 can be wrapped around the buffer layer 40 and the cell body. 22. Finally, the insulating film 30, the buffer layer 40, and the cell body 22 are installed together into the receiving cavity 12. When the buffer layer 40 is fixed on the side of the insulating film 30 facing the housing assembly 10 (the buffer layer 40 is fixed on the outer surface of the insulating film 30), the insulating film 30 can be wrapped around the cell body 22 in the external environment first, then the buffer layer 40 can be assembled on the side of the insulating film 30 facing the housing assembly 10, and finally the insulating film 30, the buffer layer 40, and the cell body 22 can be installed together into the receiving cavity 12. When the buffer layer 40 is fixed on the inner side of the housing assembly 10, the buffer layer 40 can be assembled on the inner side of the housing assembly 10 first, and then the insulating film 30 and the cell body 22 can be installed together into the receiving cavity 12. It can be seen that through the above-mentioned setting position of the buffer layer 40, the assembly space of the buffer layer 40 is not easily restricted, making the assembly of the buffer layer 40 simpler and less likely to affect the assembly efficiency of the battery cell 100.

[0083] Please refer to Figure 4, the buffer layer 40 includes at least one first buffer portion 41 and at least one second buffer portion 42. The first buffer portion 41 extends in a long strip shape along a first direction, and the second buffer portion 42 extends in a long strip shape along a second direction. The first buffer portion 41 and the second buffer portion 42 are arranged intersectingly, so that the first direction and the second direction intersect at a non-zero angle, and both the first direction and the second direction are perpendicular to the thickness direction of the housing assembly 10. For example, a single first buffer portion 41 and a single second buffer portion 42 are configured as a "cross" shape, an "X" shape, a "T" shape or an "L" shape.

[0084] It can be seen that the structures of the first buffer portion 4 and the second buffer portion 42 are relatively regular, which is beneficial to reducing the processing difficulty of the buffer layer 40 and facilitating the batch processing and manufacturing of the buffer layer 40. The first buffer portion 41 and the second buffer portion 42 are arranged intersectingly, so that at least part of the first buffer portion 41 and the second buffer portion 42 do not overlap, so that the supporting ranges of the first buffer portion 41 and the second buffer portion 42 are larger, facilitating the cell body 22 to obtain a relatively uniform supporting force and not easily generating the situation of uneven force on the cell body 22, which is beneficial to improving the reliability of the battery cell 100.

[0085] It can be understood that in the embodiment of the present application, the numbers of the first buffer portion 41 and the second buffer portion 42 may be equal or unequal. For example, when there are multiple first buffer portions 41, the multiple first buffer portions 41 may be arranged at intervals along the second direction; and / or when there are multiple second buffer portions 42, the multiple second buffer portions 42 may be arranged at intervals along the first direction.

[0086] As an example, when the buffer layer 40 includes multiple first buffer portions 41 and multiple second buffer portions 42, the first buffer portion 41 and the second buffer portion 42 are arranged intersectingly, and the multiple first buffer portions 41 and the multiple second buffer portions 42 can define a "square" shape or a "well" shape to further increase the supporting area of the buffer layer 40.

[0087] Compared with some technologies where the buffer layer is a whole-piece solid structure to improve the wrinkling problem of the electrode sheet, but the buffer layer occupies a large space in the accommodating cavity, which is not conducive to improving the energy density of the battery cell and will affect the storage amount of the electrolyte in the accommodating cavity. However, for the buffer layer 40 according to the embodiment of the present application, the first buffer portion 41 and the second buffer portion 42 are arranged intersectingly, and at least part of the first buffer portion 41 and the second buffer portion 42 do not overlap, so that the supporting ranges of the first buffer portion 41 and the second buffer portion 42 are larger, facilitating the cell body 22 to obtain a relatively uniform supporting force. And the buffer layer 40 with the above arrangement form occupies less space in the accommodating cavity 12 compared with the whole-piece solid structure buffer layer, which is beneficial to improving the energy density of the battery cell 100, and the buffer layer 40 is not likely to affect the storage amount of the electrolyte, which is beneficial to improving the service life of the battery cell 100.

[0088] Please refer to Figures 4-6 In some embodiments, there are multiple first buffer portions 41 and multiple second buffer portions 42. The multiple first buffer portions 41 are spaced apart along the second direction, and the multiple second buffer portions 42 are spaced apart along the first direction. The first direction is the height direction of the housing assembly 10, and the second direction is the length direction of the housing assembly 10. At this time, the first direction and the second direction are perpendicular.

[0089] As can be seen, the multiple first buffer portions 41 and multiple second buffer portions 42 can increase the support area of ​​the buffer layer 40, which facilitates increasing the support force of the entire buffer layer 40 on the cell body 22. This is beneficial to improving the binding force of the entire buffer layer 40 on the cell body 22, so as to further improve the electrode wrinkling phenomenon that is prone to occur due to insufficient binding of the cell body 22. The multiple first buffer portions 41 are arranged at intervals along the second direction, and the multiple second buffer portions 42 are arranged at intervals along the first direction. The dispersed arrangement of the multiple first buffer portions 41 and the multiple second buffer portions 42 facilitates increasing the support range of the first buffer portions 41 and the second buffer portions 42, so that the cell body 22 can obtain a more uniform support force, so that the cell body 22 can obtain a more stable binding force, and is less prone to electrode wrinkling phenomenon due to uneven local force, which facilitates improving the reliability of the battery cell 100.

[0090] Each first buffer section 41 intersects with all second buffer sections 42, and each second buffer section 42 intersects with all first buffer sections 41. Thus, the multiple first buffer sections 41 and multiple second buffer sections 42 can be approximately configured as a mesh structure, so that the force on the buffer layer 40 can be better dispersed, which is beneficial to improving the service life of the buffer layer 40. At the same time, the buffer layer 40 can provide a stable binding force to the cell body 22, so as to improve the reliability of the battery cell 100.

[0091] Of course, in other embodiments of this application, the first direction may also form a non-zero angle with the height direction and length direction of the housing assembly 10, and the second direction may form a non-zero angle with the height direction and length direction of the housing assembly 10, and the angle between the first direction and the second direction is an acute angle.

[0092] Please refer to Figures 4-6 In some embodiments, two first buffer portions 41 and two second buffer portions 42 are connected end to end to form a square ring structure.

[0093] As can be seen, in the above scheme, there can be two or more first buffer parts 41 and two or more second buffer parts 42. The two first buffer parts 41 and two second buffer parts 42 connected end to end can form a quadrilateral, which makes the structure of the buffer layer 40 simpler and easier to manufacture. In addition, there is a certain area inside the quadrilateral that is not covered by the first buffer part 41 and / or the second buffer part 42, so that the buffer layer 40 can provide a more suitable binding force. At the same time, the buffer layer 40 will not occupy a large space in the receiving cavity 12, which is conducive to improving the energy density of the battery cell 100. Furthermore, the buffer layer 40 is not likely to affect the amount of electrolyte stored, which is beneficial to improving the service life of the battery cell 100.

[0094] For example, two first buffer portions 41 and two second buffer portions 42 are arranged end to end. Each first buffer portion 41 has a first end and a second end that are arranged opposite each other along a first direction. Each second buffer portion 42 has a third end and a fourth end that are arranged opposite each other along a second direction. The first end of one first buffer portion 41 is connected to the third end of one second buffer portion 42, the second end of one first buffer portion 41 is connected to the third end of another second buffer portion 42, the first end of another first buffer portion 41 is connected to the fourth end of one second buffer portion 42, and the second end of another first buffer portion 41 is connected to the fourth end of another second buffer portion 42, so that the two first buffer portions 41 and the two second buffer portions 42 are configured as quadrilaterals (e.g., rectangles or squares), which has a simple structure and is convenient for the processing and manufacturing of the buffer layer 40.

[0095] Please refer to Figures 4-6 In some embodiments, the width of the first buffer portion 41 in the second direction is t1, and the width of the second buffer portion 42 in the first direction is t2, where 20mm≤t1≤60mm and 20mm≤t2≤60mm.

[0096] It can be seen that when the width of the first buffer portion 41 in the second direction and the width of the second buffer portion 42 in the first direction are too small (e.g., t1 < 20mm, t2 < 20mm), the supporting area of ​​the first buffer portion 41 and the second buffer portion 42 is small, and the binding effect of the buffer layer 40 on the cell body 22 is limited. When the width of the first buffer portion 41 in the second direction and the width of the second buffer portion 42 in the first direction are too large (e.g., t1 < 20mm, t2 < 20mm), the supporting area of ​​the first buffer portion 41 and the second buffer portion 42 in the second direction is too small (e.g., t1 < 20mm, t2 < 20mm), the supporting area of ​​the first buffer portion 41 and the second buffer portion 42 in the second direction is too large (e.g., t1 < 20mm, t (t1>20mm, t2>20mm) The first buffer part 41 and the second buffer part 42 have sufficient support area, but this will increase the space occupied by the buffer layer 40 in the receiving cavity 12, which is not conducive to improving the energy density of the battery cell 100. By setting the width of the first buffer part 41 in the second direction and the width of the second buffer part 42 in the first direction to be within the range of 20mm to 60mm, the first buffer part 41 and the second buffer part 42 have reasonable areas for supporting the cell body 22, which is conducive to reducing the problem of electrode wrinkling during the charging and discharging process of the battery cell 100. At the same time, the buffer layer 40 will not occupy a large space in the receiving cavity 12, which is conducive to improving the energy density of the battery cell 100. For example, t1 and t2 can be equal or unequal; t1 can be 20mm, 25mm, 27mm, 32mm, 36mm, 41mm, 46mm, 49mm, 52mm, 57mm, 60mm, etc.; t2 can be 20mm, 25mm, 27mm, 32mm, 36mm, 41mm, 46mm, 49mm, 52mm, 57mm, 60mm, etc.

[0097] Please refer to Figures 3-6 In some embodiments, one of the housing assembly 10, the cell assembly 20, and the insulating film 30 is bonded to the buffer layer 40.

[0098] As can be seen, the buffer layer 40 can be bonded and fixed to one of the housing assembly 10, the cell assembly 20, and the insulating film 30. For example, the buffer layer 40 can be bonded to the outside of the cell assembly 20, or the inside of the insulating film 30, or the outside of the insulating film 30, or the inside of the housing assembly 10, so that the setting position of the buffer layer 40 is more flexible and can be adapted to different installation conditions. By bonding and fixing, the assembly of the buffer layer 40 is simpler and more reliable, which can improve the assembly efficiency of the buffer layer 40 and thus improve the assembly efficiency of the battery cell 100.

[0099] Please refer to Figure 5In some embodiments, the housing assembly 10 includes a housing body 14 and a housing cover 16. The housing body 14 is open at one end in the height direction of the housing assembly 10, and the housing cover 16 is disposed on the open end of the housing body 14 to define the receiving cavity 12, which makes the assembly of the battery cell 100 more convenient. For example, the buffer layer 40, the insulating film 30 and the cell body 22 can be installed into the housing body 14 together through the open end of the housing body 14, and then the housing cover 16 is disposed on the open end of the housing body 14, thereby completing the assembly of the battery cell 100.

[0100] Please refer to Figure 5 The cell assembly 20 also includes a conductive part 24, which connects the cell body 22 and the terminal 50 of the battery cell 100. The conductive part 24 can transfer current from the cell body 22 to the external terminal 50 to realize power output or input. In the height direction of the housing assembly 10, the center of the buffer layer 40 is offset from the center of the housing body 14 in a direction away from the conductive part 24, so that the buffer layer 40 can be at a certain distance from the conductive part 24 and is less likely to affect the electrical connection between the conductive part 24 and the terminal 50.

[0101] Please refer to Figures 5-7 , Figure 11 and Figure 12 The battery cell 100 is configured to satisfy at least one of the following conditions A1 to A4:

[0102] In condition A1, the dimension of the shell 14 in the height direction of the shell assembly 10 is L1, and the dimension of the buffer layer 40 in the height direction of the shell assembly 10 is L2, where 0.9 ≤ L2 / L1 ≤ 0.98. When the ratio of the dimension of the buffer layer 40 in the height direction to the dimension of the shell 14 in the height direction is too small (e.g., L2 / L1 < 0.9), the dimension of the buffer layer 40 in the height direction of the shell assembly 10 is small, resulting in a smaller support range for the buffer layer 40 and limited restraint effect of the buffer layer 40 on the cell body 22. When the ratio of the dimension of the buffer layer 40 in the height direction to the dimension of the shell 14 in the height direction is too large (e.g., ... If L2 / L1 > 0.98, the buffer layer 40 has a larger dimension in the height direction of the housing assembly 10, providing a larger support range. However, the buffer layer 40 may come into contact with the conductive part 24, thus affecting the electrical connection between the conductive part 24 and the terminal 50. By setting the ratio of the dimension of the buffer layer 40 in the height direction to the dimension of the housing 14 in the height direction within the range of 0.9 to 0.98, the buffer layer 40 has sufficient dimension in the height direction to support the cell body 22. At the same time, the buffer layer 40 is less likely to affect the electrical connection between the conductive part 24 and the terminal 50, which helps to improve the operational stability of the battery cell 100. For example, L2 / L1 can be 0.9, 0.92, 0.95, 0.97, 0.98, etc.

[0103] In condition A2, the dimension of the cell body 22 in the height direction of the housing assembly 10 is L3, and the dimension of the buffer layer 40 in the height direction of the housing assembly 10 is L2, where 1.02 ≤ L2 / L3 ≤ 1.1. When the ratio of the dimension of the buffer layer 40 in the height direction to the dimension of the cell body 22 in the height direction is too small (e.g., L2 / L3 < 1.02), the dimension of the buffer layer 40 in the height direction of the housing assembly 10 is small, resulting in a smaller support range for the buffer layer 40. The buffer layer 40 cannot adequately cover the cell body 22, thus limiting its binding effect on the cell body 22. When the ratio of the dimension of the buffer layer 40 in the height direction to the dimension of the cell body 22 in the height direction is... When the ratio is too large (e.g., L2 / L3 > 1.1), the buffer layer 40 has a large dimension in the height direction of the housing assembly 10. While the buffer layer 40 has a large support range, it may come into contact with the conductive part 24, thus affecting the electrical connection between the conductive part 24 and the terminal 50. By setting the ratio of the height dimension of the buffer layer 40 to the height dimension of the cell body 22 in the height direction within the range of 1.02 to 1.1, the buffer layer 40 has sufficient dimension in the height direction to support the cell body 22. Simultaneously, the buffer layer 40 is less likely to affect the electrical connection between the conductive part 24 and the terminal 50, or the connection between the cover 16 and the body 14, thus improving the operational stability of the battery cell 100. Examples of L2 / L3 ratios include 1.02, 1.04, 1.06, 1.07, and 1.1.

[0104] In condition A3, the distance between the end of the buffer layer 40 facing the cover 16 and the cover 16 is t3, where 1mm ≤ t3 ≤ 3mm. For example, in the height direction of the housing assembly 10, the center of the buffer layer 40 is offset from the center of the housing body 14 in a direction away from the conductive part 24. By setting the distance between the end of the buffer layer 40 facing the cover 16 and the cover 16 in the range of 1mm to 3mm, a certain gap is maintained between the buffer layer 40 and the cover 16. This prevents the buffer layer 40 from easily contacting the conductive part 24 and thus from affecting the electrical connection between the conductive part 24 and the terminal 50, thereby improving the reliability of the battery cell 100. For example, t3 can be 1mm, 1.5mm, 2mm, 2.3mm, 2.6mm, 3mm, etc.

[0105] In condition A4, the length of the housing assembly 10 is greater than its thickness. Along the length of the housing assembly 10, the distance between the buffer layer 40 and the housing body 14 is t4, where 5mm ≤ t4 ≤ 15mm. By setting the distance between the buffer layer 40 and the housing body 14 within the range of 5mm to 15mm (i.e., the length dimension of the buffer layer 40 is smaller than the length dimension of the housing body 14), the buffer layer 40 is less likely to be interfered with by the housing body 14 during assembly. This provides more space for the assembly of the buffer layer 40, facilitating its assembly and improving the assembly efficiency of the battery cell 100. For example, t4 can be 5mm, 7mm, 8mm, 9.5mm, 11mm, 12mm, 13.5mm, 14mm, 15mm, etc.

[0106] Please refer to Figure 3 In some embodiments, the buffer layer 40 is a polymer layer that can absorb and swell. For example, when the buffer layer 40 is assembled into the receiving cavity 12, the thickness of the buffer layer 40 will not change before absorbing the electrolyte, and there is a certain empty space between the cell body 22 and the housing assembly 10. When the buffer layer 40 absorbs the electrolyte, the thickness of the buffer layer 40 increases, and the buffer layer 40 can fill the empty space between the cell body 22 and the housing assembly 10, so that the buffer layer 40 can better support the cell body 22 and facilitate the improvement of the problem of electrode wrinkling of the cell body 22 during the charging and discharging process. It is evident that by setting the buffer layer 40 as a polymer layer capable of absorbing liquid and swelling, the requirement for the thickness of the buffer layer 40 is reduced, providing more space for the assembly of the buffer layer 40 and facilitating the improvement of the assembly efficiency of the buffer layer 40. At the same time, the polymer layer can also serve as a storage pool for electrolyte. When the battery cell 100 is continuously charged and discharged, the cell body 22 will expand, and the polymer layer will be subjected to a certain amount of extrusion pressure. The extrusion pressure can squeeze out a portion of the electrolyte absorbed by the polymer layer, which can replenish the electrolyte consumed by the cell body 22 during the cycle, thus facilitating the improvement of the service life of the battery cell 100.

[0107] Optionally, the polymer layer is oriented polystyrene (OPS). OPS has good strength and rigidity, stable shape, and is not easily deformed or damaged, which enables the polymer layer to provide a more stable binding effect on the battery cell body 22. At the same time, OPS has an extremely high shrinkage rate and is not prone to wrinkles during shrinkage, which helps to improve the stability of the polymer layer in use.

[0108] Please refer to Figure 3 The polymer layer is configured to satisfy at least one of the following conditions B1 to B3:

[0109] In condition B1, the thickness of the polymer layer in the thickness direction of the housing assembly 10 is d1, and the distance between the two inner wall surfaces of the housing 14 disposed opposite each other in the thickness direction of the housing assembly 10 is d2, where d1 = 0.002 * d2. It can be understood that the thickness of the polymer layer mentioned above refers to the thickness of the polymer layer before absorbing the electrolyte. After absorbing the electrolyte, the thickness of the polymer layer will increase so that the polymer layer can provide better binding force to the cell body 22.

[0110] It can be seen that the ratio of the thickness of the polymer layer to the distance between the two inner wall surfaces of the housing assembly 10 in the thickness direction is 0.002, which makes the thickness of the polymer layer in the receiving cavity 12 more suitable. After the polymer layer absorbs the electrolyte and expands, the polymer layer can better contact the battery cell body 22, so that the polymer layer can provide a more stable binding force, which facilitates the improvement of the applicability of the buffer layer 40.

[0111] For example, the polymer layer has a thickness of 20 μm, and the distance between the two inner wall surfaces of the shell 14 disposed opposite to each other in the thickness direction of the shell assembly 10 is 10000 μm. After the polymer layer absorbs the electrolyte and expands, the polymer layer can better contact the battery cell body 22, so that the polymer layer can provide a more stable binding force.

[0112] It is understood that the distance between the polymer layer and the shell 14 on the two inner wall surfaces that are relatively disposed in the thickness direction of the shell assembly 10 can be other values, as long as the ratio of the thickness of the polymer layer to the distance between the two inner wall surfaces that are relatively disposed in the thickness direction of the shell assembly 10 is 0.002, which is conducive to improving the applicability of the buffer layer 40.

[0113] In condition B2, the thickness of the polymer layer in the thickness direction of the housing assembly 10 is d1, where 20μm≤d1≤100μm. When the thickness of the polymer layer is too small (e.g., d1<20μm), the polymer layer has limited binding force on the cell body 22 after absorbing the electrolyte. When the thickness of the polymer layer is too large (e.g., d1>100μm), the polymer layer can make better contact with the cell body 22 after absorbing the electrolyte. However, due to the large thickness of the polymer layer, the assembly of the polymer layer is not very convenient. By setting the thickness of the polymer layer in the range of 20μm to 100μm, the polymer layer can better support the cell body 22 after expansion, making the binding force provided by the polymer layer on the cell body 22 more reasonable. At the same time, the assembly of the polymer layer is less affected by the housing assembly 10, which facilitates the improvement of the assembly efficiency of the battery cell 100. For example, d1 can be 20μm, 25μm, 30μm, 35μm, 42μm, 48μm, 53μm, 57μm, 62μm, 69μm, 75μm, 81μm, 86μm, 92μm, 97μm, 100μm, etc.

[0114] In condition B3, the swelling thickness growth coefficient of the polymer layer is m, where 8 ≤ m ≤ 20. When the swelling thickness growth coefficient of the polymer layer is too small (e.g., m < 8), the binding force of the polymer layer on the cell body 22 is limited after absorbing the electrolyte. If the polymer layer is to make better contact with the cell body 22, the thickness of the polymer layer before absorbing the electrolyte needs to be increased, which makes it easy for the polymer layer to interfere with the housing assembly 10 during assembly, which is not conducive to the assembly of the battery cell 100. When the swelling thickness growth coefficient of the polymer layer is too large (e.g., m > 8), the polymer layer can make better contact with the cell body 22 after absorbing the electrolyte, but the binding force of the polymer layer on the cell body 22 may be too large, affecting the normal operation of the cell body 22. By setting the swelling thickness growth coefficient of the polymer layer in the range of 8 to 20, the assembly of the polymer layer is more convenient, and the polymer layer can make better contact with the cell body 22, making the binding force provided by the polymer layer on the cell body 22 more reasonable, which is conducive to improving the reliability of the battery cell 100. For example, m can be 8, 10, 13, 15, 16, 18, 19, 20, etc.

[0115] Please refer to Figure 3 and Figure 8 In some embodiments, the cell body 22 has a wound structure. The peripheral wall of the cell body 22 includes a flat region 22c and an arc-shaped region 22d connecting the flat region 22c. The two arc-shaped regions 22d are arranged opposite to each other along the length of the housing assembly 10. The buffer layer 40 is opposite to the flat region 22c and is offset from the arc-shaped region 22d. For example, the battery cell 100 is a flat body. Due to the manufacturing process of the wound cell body 22, the electrode spacing in the flat region 22c is small, and the stress will be concentrated on the outermost electrode when the cell body 22 expands. The outermost electrode is prone to failure. The wrinkling phenomenon can be mitigated by aligning the buffer layer 40 with the flat region 22c, allowing the buffer layer 40 to better constrain the electrode sheets in the flat region 22c and reduce the risk of wrinkling of the electrode sheets in the cell body 22. In contrast, the electrode spacing in the arc region 22d is larger, leaving some space for electrode deformation, making it less prone to stress concentration on the outermost electrode sheets and thus less likely to cause wrinkling. If the buffer layer 40 is present, the electrode sheets in the arc region 22d may be squeezed by the buffer layer 40, affecting the spacing of some electrode sheets in the arc region 22d and causing deterioration of the electrode interface in the arc region 22d.

[0116] Please refer to Figure 9 In other embodiments of this application, the cell body 22 is a stacked structure, for example, the battery cell 100 is a cuboid, and the buffer layer 40 can be set opposite to the large surface of the cell body 22 (i.e. the side with the largest area of ​​the cell body 22), which reduces the requirements for the setting position of the buffer layer 40, makes the setting position of the buffer layer 40 more flexible, and facilitates the improvement of the assembly efficiency of the buffer layer 40.

[0117] Please refer to Figure 8 In some embodiments, the cell body 22 has a wound structure. The peripheral wall of the cell body 22 includes a flat region 22c and an arc-shaped region 22d connecting the flat region 22c. The two arc-shaped regions 22d are arranged opposite to each other along the length direction of the housing assembly 10. The buffer layer 40 is opposite to the flat region 22c and staggered from the arc-shaped region 22d. The length of the housing assembly 10 is greater than the thickness of the housing assembly 10. In the length direction of the housing assembly 10, the distance between the buffer layer 40 and the shell body 14 is t4, where 5mm ≤ t4 ≤ 15mm. It can be seen that in the length direction of the housing assembly 10, the distance between the buffer layer 40 and the shell body 14 is set in the range of 5mm to 15mm so that the buffer layer 40 is less likely to come into contact with the arc-shaped region 22d, thereby reducing the possibility of the buffer layer 40 affecting the arc-shaped region 22d and facilitating the improvement of the stability of the battery cell 100.

[0118] Please refer to Figure 8 In some embodiments, the buffer layer 40 has a dimension of L4 in the length direction of the housing assembly 10, and the distance between the two inner wall surfaces disposed opposite each other in the length direction of the housing assembly 10 is L5, where 0.85≤L4 / L5≤0.95.

[0119] It is evident that when the ratio of the length dimension of the buffer layer 40 to the distance between the two inner wall surfaces opposite each other in the length direction of the housing assembly 10 is small (e.g., L4 / L5 < 0.85), the length dimension of the buffer layer 40 is small. When the cell body 22 has a wound structure, the buffer layer 40 cannot effectively cover most of the flat area 22c, thus limiting the binding effect of the buffer layer 40 on the cell body 22. Conversely, when the ratio of the length dimension of the buffer layer 40 to the distance between the two inner wall surfaces opposite each other in the length direction of the housing assembly 10 is large (e.g., L4 / L5 > 0.95), the buffer layer 40... When there is an error in the setting position, the buffer layer 40 may come into contact with the arc-shaped area 22d, thereby affecting the gap of some of the electrode sheets in the arc-shaped area 22d and easily causing deterioration of the electrode interface in the arc-shaped area 22d. By setting the ratio of the length dimension of the buffer layer 40 to the distance between the two inner wall surfaces of the housing assembly 10 that are arranged opposite each other in the length direction within the range of 0.85 to 0.95, the buffer layer 40 can have sufficient length to provide suitable binding force for the cell body 22. At the same time, the buffer layer 40 is less likely to affect the gap of some of the electrode sheets in the arc-shaped area 22d, which helps to improve the reliability of the battery cell 100. For example, L4 / L5 are 0.85, 0.87, 0.88, 0.91, 0.93, 0.95, etc.

[0120] Please refer to Figure 3 , Figure 8 and Figure 9In some embodiments, there are multiple battery cell bodies 22 arranged sequentially along the thickness direction of the housing assembly 10, and the insulating film 30 covers all battery cell bodies 22.

[0121] As can be seen, multiple cell bodies 22 can be covered by the same insulating film 30, so that multiple cell bodies 22 and insulating film 30 can be assembled together in the receiving cavity 12, making the assembly of multiple cell bodies 22 and insulating film 30 simpler and facilitating the improvement of the assembly efficiency of battery cell 100.

[0122] Among them, the outermost side of the multiple battery cell bodies 22 in the thickness direction of the housing assembly 10 is provided with a buffer layer 40. The buffer layer 40 can support the multiple battery cell bodies 22, so that the multiple battery cell bodies 22 are in closer contact and the multiple battery cell bodies 22 are less likely to have electrode wrinkling during the charging and discharging process.

[0123] Please refer to Figure 8 and Figure 9 In some embodiments, a buffer layer 40 is provided between two adjacent cell bodies 22. That is, the cell body 22 can have a buffer layer 40 on both sides in the thickness direction of the housing assembly 10. The buffer layer 40 can separate two adjacent cell bodies 22 so that the two adjacent cell bodies 22 are not likely to come into direct contact. The two adjacent cell bodies 22 can share the buffer layer 40. When the two adjacent cell bodies 22 expand, the buffer layers 40 on both sides can provide a binding force to further reduce the risk of electrode wrinkling. The buffer layer 40 between two adjacent cell bodies 22 can simultaneously provide binding for the two cell bodies 22.

[0124] Please refer to Figure 10 In some embodiments, the peripheral wall of the cell body 22 is cylindrical, for example, the battery cell 100 is cylindrical, and the buffer layer 40 is sleeved on the outside of the cell body 22.

[0125] As can be seen, the buffer layer 40 is fitted outside the cell body 22. While improving the problem of wrinkling of the outer electrode sheet of the cell body 22, the assembly of the buffer layer 40 is simpler and facilitates the improvement of the assembly efficiency of the battery cell 100.

[0126] It can be understood that when the peripheral wall of the cell body 22 is a cylindrical surface, the height direction of the housing assembly 10 is the axial direction of the cell body 22, and the length direction, width direction and axial direction of the housing assembly 10 are mutually perpendicular. The length direction of the housing assembly 10 can be one of the radial directions of the cell body 22, and the width direction of the housing assembly 10 can be another radial direction of the cell body 22.

[0127] Secondly, embodiments of this application provide a battery device 200, including a battery cell 100 as described in the first aspect.

[0128] In the above technical solution, since the battery cell 100 has a good service life, the use of the battery cell 100 can improve the service life of the battery device 200.

[0129] Thirdly, embodiments of this application provide an electrical device 300, including a battery cell 100 (first aspect) or a battery device 200 (second aspect).

[0130] In the above technical solution, since both the battery cell 100 and the battery device 200 have a good service life, using the battery cell 100 or the battery device 200 can improve the service life of the power-consuming device 300.

[0131] The following describes a specific embodiment of the battery cell 100 of this application.

[0132] Example 1, please refer to Figure 3 The battery cell 100 includes a housing assembly 10, a cell assembly 20, an insulating film 30, and a buffer layer 40.

[0133] The housing assembly 10 has a receiving cavity 12. The housing assembly 10 includes a housing body 14 and a housing cover 16. The housing body 14 is open at one end in the height direction of the housing assembly 10, and the housing cover 16 covers the open end of the housing body 14 to define the receiving cavity 12.

[0134] The cell assembly 20 is disposed in the receiving cavity 12, and the cell assembly 20 includes a cell body 22, which includes multiple anode electrode layers 22a and multiple cathode electrode layers 22b. The multiple anode electrode layers 22a and multiple cathode electrode layers 22b are alternately arranged along the thickness direction of the housing assembly 10. The cell assembly 20 also includes a conductive part 24, which connects the cell body 22 and the terminal post 50 of the battery cell 100.

[0135] An insulating film 30 is disposed in the receiving cavity 12 and covers the battery cell body 22.

[0136] The buffer layer 40 is a polymer layer capable of absorbing liquid and swelling. The buffer layer 40 is disposed in the receiving cavity 12. Along the thickness direction of the housing assembly 10, the buffer layer 40 is sandwiched between the opposite sides of the battery cell body 22 and the insulating film 30. The insulating film 30 is bonded and fixed to the buffer layer 40. Along the height direction of the housing assembly 10, the center of the buffer layer 40 is offset from the center of the housing body 14 in a direction away from the conductive part 24. The buffer layer 40 includes two first buffer parts 41 and two second buffer parts 42. The first buffer parts 41 extend in a long strip along a first direction, and the second buffer parts 42 extend in a long strip along a second direction. The structure extends in an elongated shape, with two first buffer sections 41 spaced apart along a second direction and two second buffer sections 42 spaced apart along a first direction. Each first buffer section 41 intersects with all second buffer sections 42, and each second buffer section 42 intersects with all first buffer sections 41. The two first buffer sections 41 and the two second buffer sections 42 are connected end-to-end to form a square ring structure. The first direction is the height direction of the housing assembly 10, and the second direction is the length direction of the housing assembly 10. Both the first and second directions are perpendicular to the thickness direction of the housing assembly 10.

[0137] The cell body 22 has a wound structure. The peripheral wall of the cell body 22 includes a flat area 22c and an arc-shaped area 22d connecting the flat area 22c. The two arc-shaped areas 22d are arranged opposite to each other along the length direction of the housing assembly 10. The buffer layer 40 is opposite to the flat area 22c and staggered from the arc-shaped area 22d. There are multiple cell bodies 22 arranged sequentially along the thickness direction of the housing assembly 10. The insulating film 30 covers all cell bodies 22. The multiple cell bodies 22 are provided with a buffer layer 40 on the outermost side of the housing assembly 10 in the thickness direction.

[0138] Example 2

[0139] Please refer to Figure 4 and Figure 5 The structure of the battery cell 100 provided in Embodiment 2 is largely the same as that of the battery cell 100 in Embodiment 1. The difference is that buffer layers 40 are respectively sandwiched between the opposite sides of the insulating film 30 and the housing assembly 10 in the thickness direction of the housing assembly 10, and the insulating film 30 and the buffer layers 40 are bonded and fixed.

[0140] Example 3

[0141] Please refer to Figure 6 The structure of the battery cell 100 provided in Embodiment 3 is generally the same as that of the battery cell 100 in Embodiments 1 and 2. The difference is that: in the thickness direction of the housing assembly 10, buffer layers 40 are respectively sandwiched between the opposite sides of the insulating film 30 and the housing assembly 10, and the housing assembly 10 is bonded and fixed to the buffer layers 40.

[0142] Example 4

[0143] Please refer to Figure 8 The structure of the battery cell 100 provided in Embodiment 4 is largely the same as that of the battery cell 100 in Embodiment 1, except that a buffer layer 40 is provided between two adjacent cell bodies 22.

[0144] Example 5

[0145] Please refer to Figure 9 The structure of the battery cell 100 provided in Example 5 is largely the same as that of the battery cell 100 in Example 4, except that the cell body 22 has a stacked structure.

[0146] Example 6

[0147] Please refer to Figure 10 The structure of the battery cell 100 provided in Embodiment 6 is largely the same as that of the battery cell 100 in Embodiment 1, except that the peripheral wall of the cell body 22 is cylindrical and the buffer layer 40 is sleeved on the outside of the cell body 22.

[0148] As can be seen, in the above embodiments one to six, the cell body 22 and the buffer layer 40 are both located in the receiving cavity 12. The buffer layer 40 can be used to support the cell body 22. When the battery cell 100 is continuously charged and discharged, the cell body 22 is prone to expansion and deformation. The buffer layer 40 can provide a certain resistance to the expansion of the cell body 22, that is, the buffer layer 40 can provide a binding force to the cell cell, so that the electrode is less likely to wrinkle, thereby reducing the possibility of lithium plating in the battery cell 100 and improving the service life of the battery cell 100. Moreover, the buffer layer 40 includes a first buffer portion 41 and a second buffer portion 42 that are intersected. The first buffer portion 41 and the second buffer portion 42 do not overlap in at least part of their area, so that the support range of the first buffer portion 41 and the second buffer portion 42 is larger, making it less likely to cause uneven force on the cell body 22, which is conducive to improving the reliability of the battery cell 100.

[0149] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The above are merely preferred embodiments of this application and are not intended to limit the application. For those skilled in the art, unless otherwise specified, all implementation methods and optional implementation methods of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: A housing assembly having a receiving cavity therein; A battery cell assembly is disposed in the receiving cavity, and the battery cell assembly includes a battery cell body, the battery cell body including multiple anode electrode layers and multiple cathode electrode layers, the multiple anode electrode layers and the multiple cathode electrode layers are alternately arranged along the thickness direction of the housing assembly; An insulating film is disposed in the receiving cavity and covers the battery cell body; A buffer layer is disposed in the receiving cavity. The buffer layer includes at least one first buffer portion and at least one second buffer portion. The first buffer portion extends in an elongated shape along a first direction, and the second buffer portion extends in an elongated shape along a second direction. The first buffer portion and the second buffer portion are intersecting. Both the first direction and the second direction are perpendicular to the thickness direction of the housing assembly. Wherein, in the thickness direction of the housing assembly, the buffer layer is respectively sandwiched between the opposite sides of the battery cell body and the insulating film; and / or, In the thickness direction of the housing assembly, the buffer layer is respectively sandwiched between the opposite sides of the insulating film and the housing assembly.

2. The battery cell according to claim 1, characterized in that, There are multiple first buffer portions and multiple second buffer portions. The multiple first buffer portions are spaced apart along the second direction, and the multiple second buffer portions are spaced apart along the first direction. Each first buffer portion intersects with all the second buffer portions, and each second buffer portion intersects with all the first buffer portions. The first direction is the height direction of the housing assembly, and the second direction is the length direction of the housing assembly.

3. The battery cell according to claim 2, characterized in that, Two of the first buffer sections and two of the second buffer sections are connected end to end to form a square ring structure.

4. The battery cell according to claim 1, characterized in that, The width of the first buffer part in the second direction is t1, and the width of the second buffer part in the first direction is t2, where 20mm≤t1≤60mm and 20mm≤t2≤60mm.

5. The battery cell according to claim 1, characterized in that, One of the housing assembly, the cell assembly, and the insulating film is bonded and fixed to the buffer layer.

6. The battery cell according to claim 1, characterized in that, The housing assembly includes a housing body and a housing cover. The housing body is open at one end in the height direction of the housing assembly, and the housing cover is disposed on the open end of the housing body to define a receiving cavity. The cell assembly also includes a conductive portion that connects the cell body and the terminal of the battery cell. In the height direction of the housing assembly, the center of the buffer layer is offset from the center of the housing body in a direction away from the conductive portion. The battery cell is configured to satisfy at least one of the following conditions. The shell body has a dimension L1 in the height direction of the shell assembly, and the buffer layer has a dimension L2 in the height direction of the shell assembly, where 0.9 ≤ L2 / L1 ≤ 0.98; The cell body has a dimension of L3 in the height direction of the housing assembly, and the buffer layer has a dimension of L2 in the height direction of the housing assembly, where 1.02≤L2 / L3≤1.1; The distance between the end of the buffer layer facing the shell and the shell is t3, 1mm≤t3≤3mm; The length of the housing assembly is greater than the thickness of the housing assembly, and the distance between the buffer layer and the housing body in the length direction of the housing assembly is t4, where 5mm≤t4≤15mm.

7. The battery cell according to claim 1, characterized in that, The buffer layer is a polymer layer capable of absorbing liquid and swelling, and the polymer layer is configured to satisfy at least one of the following conditions: The polymer layer has a thickness of d1 in the thickness direction of the housing assembly, and the distance between the two inner wall surfaces of the housing assembly that are disposed opposite to each other in the thickness direction is d2, where d1 = 0.002 * d2; The polymer layer has a thickness d1 in the thickness direction of the housing assembly, where 20μm≤d1≤100μm; The swelling thickness growth coefficient of the polymer layer is m, where 8 ≤ m ≤ 20.

8. The battery cell according to any one of claims 1-7, characterized in that, The battery cell body has a wound structure. The peripheral wall of the battery cell body includes a flat area and an arc-shaped area connecting the flat area. The two arc-shaped areas are arranged opposite each other along the length direction of the housing assembly. The buffer layer is opposite to the flat area and offset from the arc-shaped area; or... The battery cell body has a stacked structure.

9. The battery cell according to claim 8, characterized in that, The buffer layer has a dimension of L4 in the length direction of the housing assembly, and the distance between the two inner wall surfaces of the housing assembly that are disposed opposite each other in the length direction is L5, where 0.85≤L4 / L5≤0.

95.

10. The battery cell according to claim 8, characterized in that, The battery cell body is a plurality of cells arranged sequentially along the thickness direction of the housing assembly. The insulating film covers all the battery cell bodies, and the buffer layer is provided on the outermost side of each of the plurality of battery cell bodies in the thickness direction of the housing assembly.

11. The battery cell according to claim 10, characterized in that, The buffer layer is provided between two adjacent battery cell bodies.

12. The battery cell according to claim 1, characterized in that, The peripheral wall of the battery cell body is cylindrical, and the buffer layer is sleeved on the battery cell body.

13. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-12.

14. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1-12 or a battery device according to claim 13.

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