Battery cell, battery, and electric device

Abstract

The application provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, an electrode assembly and a support. The shell is formed with an accommodating cavity; the electrode assembly is arranged in the accommodating cavity, and the electrode assembly comprises first and second pole pieces arranged in a preset order along a first direction. The first pole piece comprises a first part coinciding with the second pole piece and a second part exceeding the second pole piece. At least part of the support is arranged between the electrode assembly and the shell along the first direction. The bending strength of the support is greater than the bending strength of the first pole piece, and the projection of the support along the first direction covers the projection of the second part along the first direction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery and an electric device. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development.

[0003] During the use of the battery in charging and discharging, the electrode assembly will swell, especially in order to improve the energy density of the battery, high expansion materials are used as negative active materials, so that the expansion problem of the negative active material during charging and discharging cycle is more prominent, which affects the performance of the battery. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in some cases. To this end, one object of the present application is to provide a battery monomer, a battery and an electric device to improve the influence of electrode expansion on the performance of the battery.

[0005] Embodiments of the first aspect of the present application provide a battery monomer, which comprises a shell, an electrode assembly and a support. The shell is formed with a receiving cavity; the electrode assembly is arranged in the receiving cavity, and the electrode assembly comprises first and second electrode sheets arranged in a preset order along a first direction, the first electrode sheet comprises a first part coinciding with the second electrode sheet and a second part extending beyond the second electrode sheet, and at least part of the support is arranged between the electrode assembly and the shell along the first direction, the bending strength of the support is greater than that of the first electrode sheet, and the projection of the support along the first direction covers the projection of the second part along the first direction.

[0006] In the technical solution of the embodiments of the present application, the support can to some extent alleviate or block the shell from pressing the second part of the first electrode sheet, thereby reducing the probability of bending or breaking of the first electrode sheet and improving the reliability of the battery monomer.

[0007] In some embodiments, the second direction is perpendicular to the first direction, the outer edge size of the support along the second direction is L2, the maximum size of the first electrode sheet along the second direction is L1, and L2>L1. Limiting the outer edge size of the support to be greater than the maximum size of the first electrode sheet along the same direction can enable the support to completely cover the first electrode sheet after expansion and extension, thereby to some extent avoiding the second part of the first electrode sheet from extending to the outside of the support after expansion and thereby directly pressing the shell.

[0008] In some embodiments, the outer dimension L2 of the support along the second direction satisfies: L2≤1.05L1. Limiting the dimension of the support along the second direction can guarantee the supporting effect to some extent while taking into account the capacity density of the battery cell.

[0009] In some embodiments, the support comprises at least one hollowed-out region and a supporting portion surrounding the at least one hollowed-out region, and the projection of the supporting portion along the first direction covers the projection of the second portion along the first direction. By providing at least one hollowed-out region on the support, the weight of the support can be reduced while maintaining its supporting effect, which can reduce the loss of energy density of the battery cell.

[0010] In some embodiments, the minimum dimension of the second tab along the second direction is L3, and the hollowed-out dimension of any one of the at least one hollowed-out region along the second direction is L4, wherein L4

[0011] In some embodiments, the support comprises a first surface facing the electrode assembly, a second surface facing away from the electrode assembly, and an inner end surface connecting the first surface and the second surface, the inner end surface defining at least one hollowed-out region; the first tab comprises a first outer end surface, and the second tab comprises a second outer end surface; along the second direction, the minimum distance between the inner end surface and the second outer end surface is P1, and the minimum distance between the first outer end surface and the second outer end surface is P2, wherein P1 / P2≥25%.

[0012] In some embodiments, the inner end surface is connected to the first surface by a bevel or a circular arc surface. When the first tab is in contact with the support, the stress is more uniform, which can alleviate the concentrated force of the support on the first tab when the first tab expands, and improve the performance of the battery cell.

[0013] In some embodiments, the support comprises a first surface facing the electrode assembly, a second surface facing away from the electrode assembly, and a third outer end surface connecting the first surface and the second surface, wherein the third outer end surface is connected to the second surface by a bevel or a circular arc surface. The bevel or circular arc surface between the third outer end surface and the second surface realizes smooth transition connection, so that when the electrode assembly expands, the third outer end surface of the support and the connection between the second surface can be in contact with the shell and extruded with relatively gentle surfaces, which is conducive to relieving stress concentration.

[0014] In some embodiments, a ratio of a thickness of the support along the first direction to a minimum thickness of the electrode assembly along the first direction in a charge-discharge cycle is greater than or equal to 0.167 and less than or equal to 0.4. Limiting the ratio of the thickness of the support to the minimum thickness of the electrode assembly along the first direction to a certain numerical range enables the support to provide sufficient bending resistance while reducing capacity loss of the battery cell.

[0015] In some embodiments, the thickness of the support along the first direction is greater than or equal to 0.2 millimeters (mm) and less than or equal to 10 millimeters (mm). Reasonably setting the thickness of the support can balance the bending resistance and the energy density of the battery cell, and improve the performance of the battery.

[0016] In some embodiments, the support is fixedly connected to a side surface of the electrode assembly facing the housing. Fixedly connecting the support to the side surface of the electrode assembly facing the housing can maintain the relative position of the support and the electrode assembly, so that the electrode assembly does not deviate from the protection range of the support even if it is deformed by swelling, thereby improving the reliability of the protection of the support.

[0017] In some embodiments, the support includes a first support and a second support, and the first support and the second support are respectively located on two sides of the electrode assembly facing the housing along the first direction. By respectively providing the support on the two sides of the electrode assembly facing the housing, the extrusion of the second part of the first electrode tab at both ends by the housing when the electrode assembly swells can be better alleviated.

[0018] In some embodiments, the material of the support is stainless steel, and the support is insulatively connected to the electrode assembly. Stainless steel has high hardness, bending strength, and corrosion resistance, and can well protect the second part of the first electrode tab.

[0019] In some embodiments, the material of the support is thermosetting plastic. The support made of thermosetting plastic has high thermal stability, which can improve its supporting effect. Moreover, the density of plastic is relatively low, and the mass is lighter under the same volume, which is conducive to the lightweight of the battery cell

[0020] In some embodiments, the material of the support is one or more of phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastic, and glass fiber reinforced plastic. Phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastic, and glass fiber reinforced plastic all have strong bending resistance and thermal stability, and can provide good support for the first electrode tab.

[0021] In some embodiments, the bending strength of the support is greater than or equal to 50 MPa and less than or equal to 300 MPa. Reasonably selecting the range of the bending strength of the support can balance the protection effect of the support and the economy of the battery cell.

[0022] In some embodiments, the energy density of the soft-pack battery cell is greater than or equal to 360 Wh / kg and less than or equal to 520 Wh / kg. By further limiting the energy density of the battery cell, the degree of swelling deformation of the electrode assembly can be controlled to some extent, so that the support, the electrode assembly and the shell can better adapt to each other, and the reliability of the battery cell is improved.

[0023] In some embodiments, the energy density of the battery cell is greater than or equal to 400 Wh / kg and less than or equal to 500 Wh / kg. By further limiting the energy density of the battery cell, the shell and the support of the battery cell can better adapt to the swelling deformation of the electrode assembly, and the reliability of the battery cell is improved.

[0024] In some embodiments, the mass percentage of the silicon-based material in the active material of the first electrode tab is greater than or equal to 20% and less than or equal to 100%. By optimizing the proportion of the silicon-based material in the negative electrode tab, the energy density of the battery cell can be effectively improved, and the performance of the battery cell is improved.

[0025] In some embodiments, the mass percentage of the silicon-based material in the active material of the first electrode tab is greater than or equal to 30% and less than or equal to 70%. By further optimizing the proportion of the silicon-based material in the active material of the negative electrode tab, the swelling size of the electrode assembly and the designed size of the support can be better adapted, which ensures the energy density of the battery cell to some extent while improving the stability and reliability of the battery cell.

[0026] Embodiments of the second aspect of the application provide a battery comprising the battery cell in the above embodiments.

[0027] Embodiments of the third aspect of the application provide a power consumption device comprising the battery or the battery cell in the above embodiments, wherein the battery or the battery cell is used to provide electric energy.

[0028] The above description is only a summary of the technical solutions of the application. In order to enable the technical means of the application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the application to be more apparent and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0029] In the drawings, like reference numerals refer to same or similar components throughout the several views. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments in accordance with the present disclosure and should not be considered limiting of the scope of the present disclosure.

[0030] Figure 1Structural schematic view of a vehicle for some embodiments of the present application;

[0031] Figure 2 Structural schematic view of a battery for some embodiments of the present application;

[0032] Figure 3 Structural schematic view of a battery cell for some embodiments of the present application;

[0033] Figure 4 Structural schematic view of a support and a tab for some embodiments of the present application;

[0034] Figure 5 Structural schematic view of a support and a tab for some embodiments of the present application;

[0035] Figure 6 Structural schematic view of a support and a tab for some embodiments of the present application Figure 5 Structural schematic view along a first direction;

[0036] Figure 7 Structural schematic view of a support and a tab for some embodiments of the present application

[0037] Figure 8 Structural schematic view of a support for some embodiments of the present application;

[0038] Figure 9 Structural schematic view of a battery cell for some embodiments of the present application

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Vehicle 1000;

[0041] Battery 100, controller 200, motor 300;

[0042] Box 10, first box 11, second box 12;

[0043] Battery cell 20, shell 21, electrode assembly 22, support 23;

[0044] Bottom wall 211, side wall 212, rounded corner 213, first tab 221, second tab 222, separator 223; first portion 2211, second portion 2212, support portion 231, hollowed-out area 232, first surface 2311, second surface 2312, inner end surface 2313, first outer end surface 221A, second outer end surface 222A, third outer end surface 2314;

[0045] First direction X, second direction Y. DETAILED DESCRIPTION

[0046] The embodiments of the present application will be described in detail below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot be used to limit the protection scope of the present application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising," "comprises" and "including" as used herein are synonymous with and meant to have the same meaning as the term "including"; the term "coupled" as used herein means the joining of two members together with one or more intervening members.

[0048] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0049] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. The skilled person in the art explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0050] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0051] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0052] In the description of the embodiments of the present application, the orientations or positional relationships indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0053] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0054] At present, from the development of market situation, the application of power battery is more and more extensive. Power battery is not only applied to energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of power battery, the demand of its market is also increasing.

[0055] With the insertion or extraction of ions by the positive active material and the negative active material in the charging and discharging cycle of the battery, the thickness of the electrode assembly system side reaction and the peeling of the graphite sheet layer cause the electrode assembly to swell, that is, the positive electrode sheet and the negative electrode sheet expand outward. The expansion of the electrode sheet has an adverse effect on the performance and service life of the battery. In order to increase the energy density of the battery, the use of silicon-based material as negative active material makes the expansion problem of silicon-based negative active material in the charging and discharging cycle more prominent. For example, the battery electrode sheet will have a large expansion and extension during the charging and discharging process, and the laminated body / rolled body will continuously press the shell, that is, the electrode assembly will continuously collide with the shell, which will cause the part of the negative electrode sheet that exceeds the positive electrode sheet to be pressed by the shell, forming a serious crease or even breaking, affecting the performance of the battery.

[0056] In the embodiments of the present application, the support member can be arranged between the electrode assembly and the shell, the bending strength of the support member is greater than the bending strength of the battery pole piece, and the support member can relieve the shell from the electrode assembly, especially the part of the negative pole piece beyond the positive pole piece, when the electrode assembly expands, thereby reducing the probability of bending or breaking of the negative pole piece and improving the reliability of the battery monomer.

[0057] The battery monomer disclosed in the embodiments of the present application can be used in, but is not limited to, an electric device such as a vehicle, a ship or an aircraft. The power supply system of the electric device can be composed of the battery monomer and the battery disclosed in the present application, so that the performance deterioration caused by the expansion of the electrode assembly can be relieved, and the stability of the battery performance and the battery life can be improved.

[0058] The embodiments of the present application provide an electric device using a battery as a power supply. The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0059] The following embodiments are described with reference to a vehicle 1000 as an example of an electric device of an embodiment of the present application for convenience of description.

[0060] Please refer to Figure 1 , Figure 1 The vehicle 1000 provided in some embodiments of the present application is shown in the structural schematic diagram. The vehicle 1000 can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid car or a range extended car, etc. The vehicle 1000 is internally provided with a battery 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as the operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation and driving.

[0061] In some embodiments of the present application, the battery 100 can not only be used as the operating power supply of the vehicle 1000, but also be used as the driving power supply of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0062] Please refer to Figure 2 , Figure 2A schematic diagram of a battery 100 is provided for some embodiments of the present application. The battery 100 includes a box 10 and a battery cell 20, which is accommodated in the box 10. The box 10 is used to provide an accommodation space for the battery cell 20, and the box 10 can adopt various structures. In some embodiments, the box 10 can include a first box 11 and a second box 12, the first box 11 and the second box 12 are mutually covered, and the first box 11 and the second box 12 jointly define an accommodation space for accommodating the battery cell 20. The second box 12 can be a hollow structure with one end open, and the first box 11 can be a plate-shaped structure, which is covered on the open side of the second box 12 to jointly define the accommodation space with the second box 12; the first box 11 and the second box 12 can also be hollow structures with one side open, and the open side of the first box 11 is covered on the open side of the second box 12. Of course, the box 10 formed by the first box 11 and the second box 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0063] In the battery 100, the battery cell 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be that the multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the box 10. The battery 100 can also include other structures, for example, the battery 100 can also include a current collecting component for realizing the electrical connection between the multiple battery cells 20.

[0064] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0065] Please refer to Figures 3-4 , Figure 3 A structural schematic diagram of a battery cell 20 is provided for some embodiments of the present application, Figure 4 A structural schematic diagram of a support and a tab is provided for some embodiments of the present application. The battery cell 20 refers to the smallest unit of the battery. As shown in Figure 3 and Figure 4 In some embodiments, the battery cell 20 includes a shell 21, an electrode assembly 22, and other functional components.

[0066] The shell 21 is formed with a receiving cavity; the electrode assembly 22 is arranged in the receiving cavity, and the electrode assembly 22 includes first and second electrode sheets 221 and 222 arranged in a preset order along a first direction X, the first electrode sheet 221 includes a first portion 2211 coinciding with the second electrode sheet 222 and a second portion 2212 extending beyond the second electrode sheet 222,

[0067] The battery cell 20 further includes a support 23, at least part of the support 23 being arranged between the electrode assembly 22 and the shell 21 along the first direction X, the support 23 having a bending strength greater than that of the first electrode sheet 221, and a projection of the support 23 along the first direction X covering a projection of the second portion 2212 along the first direction X.

[0068] The shell 21 is a component for forming an internal environment of the battery cell 20, and the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte and other components. The shell 21 includes a side wall 212 and a bottom wall 211 connected to the side wall, and the side wall 212 and the bottom wall 211 together enclose a recessed receiving cavity. The side wall 212 and the bottom wall 211 can be connected by a rounded corner transition. In one example, the receiving cavity of the shell 21 can be stamped from an aluminum plastic film material.

[0069] The electrode assembly 22 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 22 can be contained in the shell 21. The electrode assembly 22 is mainly formed by winding or stacking the first and second electrode sheets 221 and 222, and generally has a separator 223 arranged between the first and second electrode sheets 221 and 222. The first electrode sheet 221 can be a negative electrode sheet, and the second electrode sheet 222 can be a positive electrode sheet.

[0070] The first and second electrode sheets 221 and 222 have portions with active materials constituting an electrode body of the electrode assembly 22, and portions without active materials of the first and second electrode sheets 221 and 222 each constituting a tab. The positive and negative tabs can be located together at one end of the electrode body or at two ends of the electrode body, respectively. In the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0071] Along the first direction X, the first and second electrode sheets 221 and 222 are sequentially and alternately stacked, and the separator 223 is arranged between the first and second electrode sheets 221 and 222. In one example, the electrode assembly 22 is a wound cell formed by winding the first and second electrode sheets 221 and 222. In another example, the electrode assembly 22 can be a laminated cell formed by stacking the first and second electrode sheets 221 and 222.

[0072] The first tab 221 includes a first portion 2211 and a second portion 2212. The first portion 2211 overlaps the second tab 222. The overlap means that the projection of the first portion 2211 along the first direction X overlaps the projection of the second tab 222 along the first direction X. It will be appreciated that the projection of the first portion 2211 along the first direction X can completely overlap the projection of the second tab 222 along the first direction X, or can partially overlap the projection of the second tab 222 along the first direction X.

[0073] The second portion 2212 is the part of the first tab 221 that extends beyond the second tab 222. The projection of the second portion 2212 along the first direction X does not continuously overlap the projection of the second tab 222 along the same direction. In other words, the second portion 2212 is effectively a cantilevered portion that extends beyond the second tab 222. This allows the first tab 221 to completely cover the second tab 222 to reduce the probability of lithium precipitation.

[0074] During the charge and discharge cycles, the electrode assembly 22 will expand and contract. When the electrode assembly 22 expands, the electrode assembly 22 will be pressed against the housing 21. The second portion 2212 of the first tab 221 is in a cantilevered state and will be bent when it is pressed against the housing 21 due to the lack of support. In an example, the electrode assembly 22 will expand in the first direction X when it is in a charged state. At this time, the second portion 2212 of the first tab 221 will first contact the rounded corner 213 of the housing 21 and will be bent under pressure as the degree of expansion increases. The bending of the tab will adversely affect the performance of the electrode assembly 22. The repeated expansion and contraction of the electrode assembly 22 will cause the second portion 2212 to repeatedly bend, and can even cause the second portion 2212 of the first tab 221 to be cut and broken.

[0075] The support 23 is a structural member with a certain bending strength, for example, the bending strength of the support 23 is greater than the bending strength of the first tab 221. Bending strength, also known as flexural strength, is a measure of a material's ability to resist bending without breaking. The greater the bending strength, the greater the material's ability to resist bending deformation. In the bending strength test, the sample is placed between two support points, and a force is applied to bend the sample. By measuring the deformation and stress of the sample under bending load, the bending strength of the material can be calculated. Common bending test methods include three-point bending test and four-point bending test. In the three-point bending test, the sample is placed between two support points, and a force is applied in the center. In the four-point bending test, the sample is placed between two symmetrical support points, and a force is applied between the two support points.

[0076] At least part of the support 23 is arranged between the electrode assembly 22 and the shell 21 along the first direction X. In one example, the support 23 can be flat and attached to a side surface of the electrode assembly 22 facing the bottom wall 211 of the shell 21. The projection of the support 23 along the first direction X covers the projection of the second portion 2212 along the first direction X, so that the support 23 will first contact and be pressed by the shell 21 when the electrode assembly 22 expands, and the support 23 can relieve or block the shell 21 from pressing the second portion 2212 of the first tab 221 to some extent.

[0077] By arranging the support 23 with high bending strength between the electrode assembly 22 and the shell 21, the shell 21 can be relieved or blocked from pressing the second portion 2212 of the first tab 221 to some extent, thereby reducing the probability of bending or breaking of the first tab 221 and improving the reliability of the battery cell 20.

[0078] Figure 5 The structural schematic diagram of the support and the tab provided for other embodiments of the present application, Figure 6 The structural schematic diagram of the support and the tab provided for other embodiments of the present application, Figure 5 The structural schematic diagram along the first direction X.

[0079] As Figures 5-6 shown, according to some embodiments of the present application, the second direction Y is perpendicular to the first direction X, the outer edge size of the support 23 along the second direction Y is L2, the maximum size of the first tab 221 along the second direction Y is L1, and L2>L1.

[0080] The first direction X is the thickness direction of the first tab 221 and the second tab 222, the second direction Y is perpendicular to the first direction X, and the second direction Y is parallel to the surface of the first tab 221 and the second tab 222, for example, the length direction or the width direction of the first tab 221 and the second tab 222.

[0081] The first tab 221 will expand and contract in the charge and discharge cycle, so the size of the first tab 221 along the second direction Y will change with the charge and discharge, as Figure 6 shown, the outer edge of the first tab 221 before charging is S1, and the outer edge of the first tab 221 after charging and expanding is S2. The maximum size L1 of the first tab 221 along the second direction Y refers to the size of the outer edge S2 of the first tab 221 along the second direction Y when the first tab 221 expands to the maximum extent in the charge and discharge cycle. In one example, the second direction Y is the length direction of the tab, and at this time, the outer edge size L2 of the support 23 refers to the length size of the support 23, and the maximum size L1 of the first tab 221 is the maximum length after expansion. It can be understood that the second direction Y can also be the width direction of the tab, for example Figure 6 the direction indicated by the third direction Z.

[0082] Limiting the outer edge size of the support 23 to be greater than the maximum size of the first pole piece 221 along the same direction Y can enable the support 23 to completely cover the first pole piece 221 after expansion and extension, and to some extent avoid the second portion 2212 of the first pole piece 221 from expanding and extending to the outside of the support 23 and directly pressing against the shell 21.

[0083] According to some embodiments of the present application, the outer edge size L2 of the support 23 along the second direction Y satisfies: L2≤1.05L1.

[0084] The greater the second size of the support 23 along the second direction Y, the greater the loss of the capacity density of the battery cell, and therefore it is necessary to limit the size of the support 23 along the second direction Y, so as to provide a supporting effect while taking into account the capacity density of the battery cell.

[0085] Figure 7 The structural schematic diagram of the support and the pole piece provided for yet some embodiments of the present application is shown. According to some embodiments of the present application, as shown in Figure 7 The support 23 includes at least one hollow area 232 and a support portion 231 surrounding the at least one hollow area 232, and the projection of the support portion 231 along the first direction X covers the projection of the second portion 2212 along the first direction X.

[0086] The hollow area 232 refers to an area penetrating through the support 23 along the first direction X. The number of hollow areas 232 can be one or multiple, for example, multiple hollow areas 232 arranged at intervals. The shape of the hollow area 232 can be any shape, for example, circular, square, etc. The projection of the support portion 231 along the first direction X covers the projection of the second portion 2212 along the first direction X, so that the projection range of the second portion 2212 along the first direction X on the support 23 falls completely within the range of the support portion 231. In one example, the support 23 is a frame-shaped with a hollow in the middle.

[0087] By providing at least one hollow area 232 on the support 23, the weight of the support 23 can be reduced while maintaining its supporting effect, so as to reduce the loss of the energy density of the battery cell.

[0088] According to some embodiments of the present application, the minimum size of the second pole piece 222 along the second direction Y is L3, the hollow size of any one of the at least one hollow area 232 along the second direction Y is L4, and L4

[0089] Since the second electrode 222 coincides with the first portion 2211 of the first electrode 221, the dimension of the second electrode 222 along the second direction Y is actually the same as the dimension of the first portion 2211 along the second direction Y. The minimum dimension L3 of the second electrode 222 along the second direction Y refers to the minimum dimension of the second electrode 222 along the second direction Y during a charge-discharge cycle. The fact that the cutout dimension L4 of the cutout area 232 along the second direction Y is less than L3 means that at least a portion of the support portion 231 has a projection along the first direction X that coincides with the first portion 2211 of the first electrode 221.

[0090] In this embodiment, the size of the hollow area 232 along the second direction Y is smaller than the minimum size of the second pole piece 222 along the same direction, so that the support part 231 can coincide with the first part 2211, which can provide a certain support force for the support part 231 and thus improve the support effect of the support member 23.

[0091] According to some embodiments of this application, the support portion 231 of the support member 23 includes a first surface 2311 facing the electrode assembly 22, a second surface 2312 facing away from the electrode assembly 22, and an inner end face 2313 connecting the first surface 2311 and the second surface 2312, the inner end face 2313 defining at least one hollow area 232. The first electrode 221 includes a first outer end face 221A, and the second electrode 222 includes a second outer end face 222A; along the second direction Y, the minimum distance between the inner end face 2313 and the second outer end face 222A is P1, and the minimum distance between the first outer end face 221A and the second outer end face 222A is P2, wherein P1 / P2≥25%.

[0092] The inner end face 2313 is the surface located between the first surface 2311 and the second surface 2312, facing the hollow area 232. The first outer end face 221A is the outer end face of the first electrode 221 along the thickness direction, and the second outer end face 222A is the outer end face of the second electrode 222 along the thickness direction.

[0093] like Figure 7 As shown, the minimum distance P1 between the inner end face 2313 and the second outer end face 222A is actually the minimum dimension of the portion of the support portion 231 extending from the inner end face to the outer end face that coincides with the second electrode 222 or the first portion 2211 of the first electrode 221 along the second direction Y. The minimum distance P2 between the first outer end face 221A and the second outer end face 222A is the minimum dimension of the portion of the first electrode 221 that extends beyond the second electrode 222 along the second direction Y, and is also the minimum dimension of the second portion 2212 located at one end of the first electrode 221 along the second direction Y.

[0094] In this embodiment, P1 and P2 satisfy: P1 / P2≥25%. For example, P1 can be 25% P2, so that a large enough contact area can be formed between the support portion 231 and the first portion 2211 of the first pole piece 221 to provide sufficient support force for the support member 23. In one example, P1 can also be 30% P2, 50% P2, or 100% P2.

[0095] Since the second portion 2212 of the first pole piece 221 is in a suspended state, it is essentially unable to provide support force for the support member 23, and the purpose of arranging the support member 23 is to avoid or alleviate the transmission of the extrusion force of the shell to the second portion 2212 to some extent, so the support force can be provided by the contact between the first portion 2211 of the first pole piece 221 and the support member 23. By limiting the value range of the ratio of P1 and P2, a large enough contact area can be formed between the first portion 2211 of the first pole piece 221 and the support member 23 to provide sufficient support force for the support member 23, and the larger P1 is, the larger the width of the support portion 231 is, and the smaller the hollow area 232 is, which is beneficial to improve the anti-deformation capability of the support member 23 as a whole.

[0096] Figure 8 A structural schematic diagram of the support member 23 is provided for some embodiments of the present application. According to some embodiments of the present application, as shown in Figure 8 The inner end surface 2313 is connected to the first surface 2311 through a bevel or a circular arc surface.

[0097] The bevel can be a bevel formed by chamfering between the inner end surface 2313 and the first surface 2311, and the circular arc surface can be a circular arc surface formed by rounding between the inner end surface 2313 and the first surface 2311.

[0098] The first pole piece 221 expands when charging due to the insertion of lithium ions, and the first portion 2211 receives more lithium ions and expands to a greater extent than the second portion 2212 because it coincides with the second pole piece 222. The smooth transition connection between the inner end surface 2313 and the first surface 2311 through the bevel or the circular arc surface makes the force more uniform when the first pole piece 221 contacts the support member 23, which can alleviate the concentrated force of the support member 23 on the first pole piece 221 when the first pole piece 221 expands, and improve the performance of the battery monomer 20.

[0099] According to some embodiments of the present application, as shown in Figure 8 The support member 23 further includes a third outer end surface 2314 connecting the first surface 2311 and the second surface 2312, and the third outer end surface 2314 is connected to the second surface 2312 through a bevel or a circular arc surface.

[0100] The third outer end surface 2314 is an outer end surface opposite to the inner end surface 2313. The bevel can be a bevel formed by chamfering between the third outer end surface 2314 and the second surface 2312. The arc surface can be an arc surface formed by rounding between the third outer end surface 2314 and the second surface 2312.

[0101] The third outer end surface 2314 and the second surface 2312 are connected through the bevel or the arc surface to achieve smooth transition, so that when the electrode assembly 22 expands, the connection between the third outer end surface 2314 and the second surface 2312 of the support 23 can be in contact with the shell 21 and extruded by a relatively gentle surface, which is beneficial to alleviate stress concentration.

[0102] Figure 9 A structural schematic diagram of a battery cell 20 provided for another embodiment of the present application. According to some embodiments of the present application, as shown in Figure 9 The ratio of the thickness T0 of the support 23 along the first direction X to the minimum thickness of the electrode assembly 22 along the first direction in the charge-discharge cycle is greater than or equal to 0.167 and less than or equal to 0.4.

[0103] The minimum thickness T1 is the minimum thickness of the electrode assembly 22 along the first direction X in the charge-discharge cycle, and the maximum thickness T2 is the maximum thickness of the electrode assembly 22 along the first direction X in the charge-discharge cycle. As shown in Figure 9 In the charge-discharge cycle, the thickness of the electrode assembly 22 along the first direction X will expand from the minimum thickness T1 to the maximum thickness T2, and then in the discharge process, the thickness of the electrode assembly 22 along the first direction X will shrink from the maximum thickness T2 to the minimum thickness T1. Therefore, the maximum expansion thickness is (T2-T1).

[0104] It can be understood that the support 23 can be a flat plate with uniform thickness, and the thickness of the support 23 along the first direction X is a uniform thickness T0. The bevel or arc surface between the third outer end surface 2314 and the second surface 2312 and between the inner end surface 2313 and the first surface 2311 is only a change at the local connection and does not substantially affect the thickness of the support 23.

[0105] The greater the thickness of the electrode assembly 22, the greater the maximum expansion thickness (T2-T1) of the electrode assembly 22 along the first direction X under other conditions, so that the extrusion of the shell 21 on the second part 2212 of the first tab 221 is more intense, so that the requirement for the bending resistance of the support 23 is higher, and in the case of a certain material, the greater the thickness of the support 23, the stronger the bending resistance. However, if the thickness of the support 23 is too large, it will also cause a large capacity loss of the battery cell 20, which is not conducive to the improvement of the energy density of the battery cell 20.

[0106] In one example, the minimum thickness T1 of the electrode assembly 22 is in a range of 0.5 mm to 60 mm, and the ratio of the maximum expansion thickness (T2-T1) in the charge-discharge cycle to the minimum thickness T1 of the electrode assembly 22 is the expansion change rate of the electrode assembly 22, which is in a range of 5% to 45%. The thickness T0 of the support 23 can be selected according to the minimum thickness of the electrode assembly 22, and can be further adjusted in combination with the material and bending strength of the support 23, so that the thickness of the support 23 meets the support requirement while minimizing the capacity loss of the battery cell 20.

[0107] The higher the proportion of the high-expansion material in the first tab 221 of the electrode assembly 22, the greater the expansion deformation of the first tab 221 during charging, and the more severe the extrusion of the electrode assembly 22 against the shell 21, and the greater the possibility of the second portion 2212 of the first tab 221 being pressed, bent, or even broken. Therefore, the support 23 needs to have greater bending strength to alleviate the degree of pressure bending of the second portion 2212 of the first tab 221. The thickness of the support 23 is positively correlated with the bending strength of the support 23. The ratio of the thickness T0 of the support 23 to the minimum thickness T1 of the electrode assembly 22 in the first direction in the charge-discharge cycle is set to satisfy 0.167≤T0 / T1≤0.4, so that the support has sufficient bending strength to alleviate the extrusion of the shell 21 against the first tab 221, while minimizing the capacity loss of the battery cell 20.

[0108] According to some embodiments of the present application, the thickness of the support 23 in the first direction X is in a range of greater than or equal to 0.2 millimeters (mm) and less than or equal to 10 millimeters (mm).

[0109] In some embodiments, the support 23 is a flat plate with uniform thickness. The thickness of the support 23 can be negatively correlated with the elastic modulus of the support 23. For example, the greater the elastic modulus, the thinner the thickness of the support 23 can be. Conversely, the smaller the elastic modulus, the greater the thickness of the support 23 needs to be, so as to ensure that the support 23 has sufficient bending performance to a certain extent.

[0110] By reasonably setting the thickness of the support 23, the bending performance and the energy density of the battery cell 20 can be considered, and the performance of the battery can be improved.

[0111] According to some embodiments of the present application, the support 23 is fixedly connected to the side surface of the electrode assembly 22 facing the shell 21.

[0112] The support 23 can be fixedly connected to the side surface of the electrode assembly 22 facing the shell 21. For example, the support 23 can be fixedly connected to the surface of the electrode assembly 22 by adhesion.

[0113] The fixing connection of the support 23 and the electrode assembly 22 facing the side surface of the shell 21 can keep the relative position of the support 23 and the electrode assembly 22, so that the electrode assembly 22 will not be out of the supporting range of the support 23 even if it is deformed by swelling, and the reliability of the protection of the support is improved.

[0114] In some embodiments, as shown in Figure 3 The support 23 includes a first support 23A and a second support 23B, which are respectively located on the two sides of the electrode assembly 22 facing the shell 21 along the first direction X.

[0115] The first support 23A and the second support 23B are respectively located on the two sides of the electrode assembly 22 along the first direction X, and the first support 23A and the second support 23B can be of the same material and structure, or of different materials and structures. In one example, the first support 23A can be a flat plate, and the second support 23B can also be a frame.

[0116] By respectively arranging the support 23 on the two sides of the electrode assembly 22 facing the shell 21, the extrusion of the second part 2212 of the first tab 221 at both ends of the shell 21 when the electrode assembly 22 swells can be better alleviated, and the structural stability of the battery monomer 20 is further improved.

[0117] According to some embodiments of the present application, the material of the support 23 is stainless steel, and the support 23 is insulatedly connected with the electrode assembly 22.

[0118] The support 23 made of stainless steel needs to be insulatedly connected with the electrode assembly 22 due to the electrical conductivity of stainless steel. In one example, the insulation connection between the support 23 and the electrode assembly 22 can be achieved through an insulating adhesive layer.

[0119] Stainless steel has high hardness, bending strength and corrosion resistance, and can well protect the second part of the first tab. At the same time, the support 23 made of stainless steel can be appropriately set to be thinner, so that the weight and the occupied volume can be reduced, which is beneficial to improve the energy density of the battery.

[0120] According to some embodiments of the present application, the material of the support 23 is thermosetting plastic.

[0121] Thermosetting plastic is a plastic with thermosetting resin as the main component, combined with various necessary additives to form a product through a cross-linking curing process. The characteristics of thermosetting plastic are that it hardens after a certain time of heating, pressing or adding a hardening agent at a certain temperature. After hardening, the chemical structure of the plastic changes, the texture is hard, it is insoluble in solvents, and it does not soften again when heated.

[0122] Since the electrode assembly 22 generates heat in the charge and discharge cycle, the support 23 made of thermosetting plastic has high thermal stability, which can improve the supporting effect. Moreover, the density of plastic is low, and the mass is lighter under the same volume, which is conducive to the lightweight of the battery monomer 20.

[0123] According to some embodiments of the present application, the material of the support 23 is one or more of phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastic, and glass fiber reinforced plastic.

[0124] Phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastic, and glass fiber reinforced plastic all have strong bending resistance and thermal stability, which can provide good support for the first electrode sheet 221.

[0125] According to some embodiments of the present application, the bending strength of the support 23 is greater than or equal to 50 MPa and less than or equal to 300 MPa.

[0126] The bending strength of the support 23 is directly related to the protection effect of the support 23 on the second part 2212 of the first electrode sheet 221. If the bending strength of the support 23 is too small, the deformation is too large when being extruded and deformed with the shell 21, and it cannot meet the requirement of protecting the first electrode sheet 221. If the bending strength is too high, it means that the material performance is excessive, which is also not conducive to the economy of the battery.

[0127] Reasonably selecting the range of the bending strength of the support 23 can take into account the protection effect of the support 23 and the economy of the battery monomer 20.

[0128] In some embodiments, the energy density of the battery monomer 20 is greater than or equal to 360 Wh / kg (watt-hour / kilogram) and less than or equal to 520 Wh / kg (watt-hour / kilogram).

[0129] The energy density refers to the energy released by the battery per unit mass or per unit volume, that is, the volume specific energy or the mass specific energy. In this embodiment, the energy density of the battery monomer 20 refers to the mass specific energy.

[0130] In some embodiments, the greater the energy density of the battery monomer 20, the more high-expansion materials contained in the active material of the electrode sheet, which makes the expansion degree of the electrode assembly 22 larger, and the problem of collision and extrusion between the electrode assembly 22 and the shell 21 is more prominent.

[0131] The energy density of the battery cell 20 has a direct impact on the degree of expansion of the electrode assembly 22 in the charge-discharge cycle. By further limiting the energy density of the battery cell 20, the degree of expansion and deformation of the electrode assembly 22 can be controlled to some extent, so that the support 23, the electrode assembly 22 and the shell 21 can better adapt to each other, and the reliability of the battery cell 20 can be improved.

[0132] In some embodiments, the energy density of the battery cell 20 is greater than or equal to 400 Wh / kg and less than or equal to 500 Wh / kg.

[0133] By further limiting the energy density of the battery cell 20, the shell 21 and the support 23 of the battery cell 20 can better adapt to the expansion and deformation of the electrode assembly 22, and the reliability of the battery cell 20 can be improved.

[0134] In some embodiments, the mass percentage of the silicon-based material in the active material of the first electrode sheet 221 is greater than or equal to 20% and less than or equal to 100%.

[0135] The first electrode sheet 221 is a negative electrode sheet, and the active material of the first electrode sheet 221 can include a high-expansion material, which in some embodiments can be a silicon-based material. Silicon-based negative electrode materials have the advantages of high theoretical specific capacity, low delithiation potential, environmental friendliness, abundant reserves, and low cost. Silicon is more prone to expansion during charging and discharging because silicon crystals have a tetrahedral structure (graphite has a layered structure).

[0136] In some examples, the silicon-based material is selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The elemental silicon can be pure silicon, such as silicon nanoparticles, silicon nanowires, and silicon nanotubes with a nanoscale size. The silicon oxide compound can be silicon suboxide (SiOx) composed of silicon and silicon dioxide. The silicon-carbon composite can be a silicon-carbon composite (Si / C) formed by coating carbon on the surface of silicon. The silicon-nitrogen composite can be a composite of silicon suboxide and nitrogen-doped carbon, a silicon-carbon nitride composite, or a nanoscale silicon-nitrogen-coated carbon composite material.

[0137] Using a silicon-based material as the negative electrode material of the battery cell can improve the energy density of the battery cell and improve the performance of the battery. By optimizing the proportion of the silicon-based material in the negative electrode sheet, the energy density of the battery cell can be effectively improved, and the performance of the battery cell can be improved.

[0138] In some embodiments, the mass percentage of the silicon-based material in the active material of the first electrode sheet 221 is greater than or equal to 30% and less than or equal to 70%.

[0139] By further preferably setting the proportion of the silicon-based material in the active material of the first tab 221, the expansion size of the electrode assembly 22 can be better adapted to the design size of the support 23, thereby ensuring the energy density of the battery cell to some extent while improving the stability and reliability of the battery cell.

[0140] Embodiments of the second aspect of the application provide a battery 100 comprising the battery cell 20 in the above embodiments.

[0141] Embodiments of the third aspect of the application provide a power consumption device comprising the battery 100 or the battery cell 20 in the above embodiments, and the battery 100 or the battery cell 20 is configured to provide electric energy.

[0142] The battery cell 20 of the application will be further described below in combination with a specific embodiment.

[0143] The battery cell 20 comprises a housing 21, an electrode assembly 22, and other functional components.

[0144] The housing 21 is formed with an accommodation cavity; the electrode assembly 22 is arranged in the accommodation cavity, and the electrode assembly 22 comprises first tabs 221 and second tabs 222 arranged in a preset order along a first direction X, and a separator 223 located between the first tabs 221 and the second tabs 222, the first tabs 221 comprise first portions 2211 coinciding with the second tabs 222 and second portions 2212 exceeding the second tabs.

[0145] The battery cell 20 further comprises a support 23, at least part of the support 23 is arranged between the electrode assembly 22 and the housing 21 along the first direction X, the bending strength of the support 23 is greater than the bending strength of the first tabs 221, and the projection of the support 23 along the first direction X covers the projection of the second portions 2212 along the first direction X.

[0146] A second direction Y is perpendicular to the first direction X, the outer edge size of the support 23 along the second direction Y is L2, the maximum size of the first tabs 221 along the second direction Y is L1, and L1 < L2 ≤ 1.05L1 is satisfied.

[0147] The support 23 can be a flat plate or a frame. In one example, the support 23 comprises at least one hollow area 232 and a support portion 231 surrounding the at least one hollow area 232, and the projection of the support portion 231 along the first direction X covers the projection of the second portions 2212 along the first direction X. The minimum size of the second tabs 222 along the second direction Y is L3, the hollow size of any one of the at least one hollow area 232 along the second direction Y is L4, and L4 < L3 is satisfied.

[0148] The support part 231 of the support 23 includes a first surface 2311 facing the electrode assembly 22, a second surface 2312 facing away from the electrode assembly 22, an inner end surface 2313 connecting the first surface 2311 and the second surface 2312, and a third outer end surface 2314 connecting the first surface 2311 and the second surface 2312. The first tab 221 includes a first outer end surface 221A, and the second tab 222 includes a second outer end surface 222A. In the second direction Y, the minimum distance between the inner end surface 2313 and the second outer end surface 222A is P1, and the minimum distance between the first outer end surface 221A and the second outer end surface 222A is P2, where P1 / P2≥25%.

[0149] The inner end surface 2313 is connected to the first surface 2311 by a bevel or a circular arc surface, and the third outer end surface 2314 is connected to the second surface 2312 by a bevel or a circular arc surface.

[0150] The ratio of the thickness T0 of the support 23 in the first direction X to the minimum thickness T1 of the electrode assembly 22 in the first direction X in the charge-discharge cycle satisfies: 0.167≤T0 / T1≤0.4. In some embodiments, the thickness of the support 23 in the first direction X is greater than or equal to 0.2 millimeters (mm) and less than or equal to 10 millimeters (mm).

[0151] The material of the support 23 can be stainless steel or thermosetting plastic. The bending strength of the support 23 is greater than or equal to 50 MPa and less than or equal to 300 MPa.

[0152] The energy density of the battery cell 20 is greater than or equal to 400 Wh / kg and less than or equal to 500 Wh / kg, and the mass percentage of silicon-based material in the active material of the first tab 221 is greater than or equal to 30% and less than or equal to 70%.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The shell has a receiving cavity; An electrode assembly is disposed within the receiving cavity. The electrode assembly includes a first electrode and a second electrode arranged in a preset order along a first direction. The first electrode includes a first portion overlapping the second electrode and a second portion extending beyond the second electrode. The first electrode includes a first outer end face parallel to the thickness direction, and the second electrode includes a second outer end face parallel to the thickness direction. A support member, at least a portion of which is disposed between the electrode assembly and the housing along the first direction, wherein the bending strength of the support member is greater than the bending strength of the first electrode sheet, the support member is a frame shape with a hollow center, the support member includes at least one hollow area and a support portion surrounding the at least one hollow area, and the inner end face of the support portion defines the at least one hollow area. Wherein, the projection of the support member along the first direction covers the projection of the second part along the first direction; Furthermore, in a plane perpendicular to the first direction, the orthographic projection of the second outer end face lies between the orthographic projection of the first outer end face and the orthographic projection of the inner end face.

2. The battery cell according to claim 1, characterized in that, The second direction is perpendicular to the first direction. The outer edge dimension of the support member along the second direction is L2, the maximum dimension of the first electrode along the second direction is L1, and L2 > L1.

3. The battery cell according to claim 2, characterized in that, The outer edge dimension of the support member along the second direction satisfies: L2≤1.05L1.

4. The battery cell according to claim 1, characterized in that, The minimum dimension of the second electrode along the second direction is L3, and the dimension of any one of the at least one hollowed-out area along the second direction is L4, wherein L4 < L3, and the second direction is perpendicular to the first direction.

5. The battery cell according to claim 1, characterized in that, The support includes a first surface facing the electrode assembly, a second surface facing away from the electrode assembly, and an inner end face connecting the first surface and the second surface; Along a second direction perpendicular to the first direction, the minimum distance between the inner end face and the second outer end face is P1, and the minimum distance between the first outer end face and the second outer end face is P2, wherein P1 / P2≥25%.

6. The battery cell according to claim 5, characterized in that, The inner end face is connected to the first surface via a bevel or a circular arc surface.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The support member includes a first surface facing the electrode assembly, a second surface facing away from the electrode assembly, and a third outer end surface connecting the first surface and the second surface. The third outer end face is connected to the second surface by a slope or a circular arc surface.

8. The battery cell according to any one of claims 1 to 6, characterized in that, The ratio of the thickness of the support member along the first direction to the minimum thickness of the electrode assembly along the first direction during charge-discharge cycles is greater than or equal to 0.167 and less than or equal to 0.

4.

9. The battery cell according to any one of claims 1 to 6, characterized in that, The thickness of the support member along the first direction is greater than or equal to 0.2 mm and less than or equal to 10 mm.

10. The battery cell according to any one of claims 1 to 6, characterized in that, The support member is fixedly connected to the side surface of the electrode assembly facing the housing.

11. The battery cell according to any one of claims 1 to 6, characterized in that, The support includes a first support and a second support, which are respectively located on both sides of the electrode assembly facing the housing along the first direction.

12. The battery cell according to any one of claims 1 to 6, characterized in that, The support is made of stainless steel and is insulated from the electrode assembly.

13. The battery cell according to any one of claims 1 to 6, characterized in that, The support component is made of thermosetting plastic.

14. The battery cell according to claim 13, characterized in that, The support component is made of one or more of the following materials: phenolic plastic, epoxy plastic, amino plastic, unsaturated polyester, alkyd plastic, and glass fiber reinforced plastic.

15. The battery cell according to any one of claims 1 to 6, characterized in that, The bending strength of the support is greater than or equal to 50 MPa and less than or equal to 300 MPa.

16. The battery cell according to any one of claims 1 to 6, characterized in that, The energy density of the battery cell is greater than or equal to 360Wh / kg and less than or equal to 520Wh / kg.

17. The battery cell according to claim 16, characterized in that, The energy density of the battery cell is greater than or equal to 400Wh / kg and less than or equal to 500Wh / kg.

18. The battery cell according to any one of claims 1 to 6, characterized in that, The mass percentage of silicon-based material in the active material of the first electrode is greater than or equal to 20% and less than or equal to 100%.

19. The battery cell according to claim 18, characterized in that, The mass percentage of silicon-based material in the active material of the first electrode is greater than or equal to 30% and less than or equal to 70%.

20. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 19.

21. An electrical appliance, characterized in that, The electrical device includes a battery cell as described in any one of claims 1 to 19 or a battery as described in claim 20, wherein the battery cell or the battery is used to provide electrical energy.

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