Battery monomer, battery device and electric equipment

Abstract

The utility model relates to the technical field of battery equipment, and discloses a battery monomer, a battery device and electric equipment. Wherein the battery monomer comprises an electrode assembly, a first reinforcing piece and a second reinforcing piece, the electrode assembly comprises a cathode pole piece, an anode pole piece and a diaphragm, the cathode pole piece, the diaphragm and the anode pole piece are laminated, the electrode assembly is wound to form a straight part and a bent part, at least part of the first reinforcing piece is located at the bent part, and at least part of the second reinforcing piece is located at the bent part. A first reinforcing piece is arranged between the adjacent cathode pole piece and anode pole piece, a second reinforcing piece is arranged between the cathode pole piece and anode pole piece, the second reinforcing piece protrudes out of one end, facing the straight part, of the first reinforcing piece in the first direction, and the second reinforcing piece protrudes out of the other end, facing the straight part, of the first reinforcing piece in the projection direction. The side edge, facing the bent part, of the projection of the second reinforcer is at least connected with the side edge of the projection of the first reinforcer, and the second reinforcer is provided with a hole communicating the two sides of the second reinforcer in the second direction. By applying the technical scheme, the problem that metal dendrites are easy to separate out at the bending part of the electrode assembly to cause short circuit in the battery single body is solved.

Description

Technical Field

[0001] This application belongs to the field of battery equipment technology, and in particular relates to a battery cell, battery device and electrical equipment. Background Technology

[0002] The electrode assembly of a battery cell can be formed by winding, which creates both straight and curved sections. During winding, the inner radius is compressed while the outer radius is stretched. Over time, metal dendrites can easily precipitate on the anode electrode in the curved section. These dendrites can compress and damage the separator, and subsequently contact the cathode electrode, causing an internal short circuit within the battery cell. In severe cases, thermal runaway can occur, leading to a decrease in the stability and reliability of the battery cell. Utility Model Content

[0003] The purpose of this application is to provide a battery cell, battery device, and electrical equipment, which aims to solve the problem that metal dendrites are easily deposited in the bent part of the electrode assembly, leading to internal short circuits in the battery cell.

[0004] To achieve the above objectives, according to a first aspect of the embodiments of this application, a battery cell is provided, including an electrode assembly, a first reinforcing member, and a second reinforcing member. The electrode assembly includes a cathode electrode, an anode electrode, and a separator. The cathode electrode, separator, and anode electrode are sequentially stacked and wound. The electrode assembly is wound to form a straight portion and curved portions located on both sides of the straight portion. At least a portion of the first reinforcing member is located in the curved portion, and at least one layer of the first reinforcing member is provided between adjacent cathode and anode electrodes. The second reinforcing member is disposed between the cathode and anode electrodes. The second reinforcing member protrudes along a first direction from one end of the first reinforcing member facing the straight portion, and a second direction perpendicular to the first direction is used as the projection direction. The side of the projection of the second reinforcing member facing the curved portion is at least connected to the side of the projection of the first reinforcing member. The second reinforcing member has a hole connecting its two sides along the second direction.

[0005] In the battery cell provided in the embodiments of this application, the electrode assembly of the battery cell is formed by winding a cathode electrode, an anode electrode, and a separator after being stacked. This winding creates a straight portion and curved portions on both sides of the straight portion. In the curved portions, because the bending radii of the stacked cathode and anode electrodes at different layers are different, and because the radially inner side of each layer of cathode and anode electrodes in the curved portion is under bending compression and the radially outer side is under bending tension, bending stress exists on the cathode and anode electrodes in the curved portion. To address this, the electrode assembly of the battery cell is provided with a first reinforcing member. This first reinforcing member can reliably and stably function in the curved portion, providing a buffering effect against bending stress on the cathode and anode electrodes in the curved portion. This reduces the possibility of tearing of the cathode and anode electrodes in the curved portion (especially the radially outer sides of the cathode and anode electrodes in the curved portion), thereby reducing the possibility of metal dendrite precipitation at the tear site. However, due to the physical property of insufficient negative electrode capacity in the local area of ​​the anode electrode near the straight portion of the first reinforcing member, metal will precipitate and accumulate on the side of the anode electrode facing the cathode electrode during long-term use of the battery cell, forming metal dendrites. The continuously accumulating and growing metal dendrites will exert compressive and shear stress on the cathode electrode and the separator located between the anode and cathode electrodes, which will cause the cathode electrode to be torn by compression or the metal dendrites to damage the separator and overlap onto the cathode electrode, resulting in battery cell failure or internal short circuit causing thermal runaway. To address this, the battery cell is provided with a second reinforcing member, which is located between the cathode electrode and the anode electrode. The second reinforcing member protrudes from the end of the first reinforcing member facing the straight portion along a first direction, and the side of the projection of the second reinforcing member facing the curved portion is at least in contact with the side of the projection of the first reinforcing member. The second reinforcing member has pores connecting its two sides along the second direction to allow metal ions to pass through. Thus, the second reinforcing member can enhance the load-bearing capacity of the cathode electrode, such as tensile strength, tear resistance, and bending resistance, and can suppress cathode electrode breakage. Furthermore, the second reinforcing member can support and balance the extrusion and shearing effects of metal dendrites, thereby reducing the possibility of metal dendrites extruding and damaging the separator, which in turn reduces the possibility of metal dendrites contacting the cathode electrode. This reduces the possibility of internal short circuits in the battery cell, reduces the possibility of thermal runaway, and improves the stability and reliability of the battery cell.

[0006] In some embodiments, the cathode electrode includes a current collector and a cathode active material layer disposed on both sides of the current collector, and a second reinforcing member is disposed between the current collector and the diaphragm.

[0007] In some embodiments, the second reinforcing member is attached to the side of the cathode active material layer away from the current collector.

[0008] In some embodiments, the second reinforcing member is embedded in the cathode active material layer. The second reinforcing member can reduce the amount of cathode active material at its location, which to some extent reduces the number of electrons released from that location of the cathode electrode to the anode electrode, thereby reducing the possibility of metal deposition in the local area of ​​the anode electrode corresponding to the second reinforcing member near the straight portion of the first reinforcing member.

[0009] In some embodiments, the projection of the second reinforcing member along the second direction overlaps with the projection of the first reinforcing member along the second direction. Furthermore, the length of the overlapping region along the first direction is L, where 50 μm ≤ L ≤ 5 mm. Thus, even if the cathode electrode undergoes expansion and stretching, the likelihood of a gap appearing between the second and first reinforcing members during this process is reduced, decreasing the possibility of compressive shear stress exerted by metal dendrites on this gap. The second reinforcing member can consistently provide enhanced support, thereby reducing the possibility of metal dendrites compressing and damaging the diaphragm.

[0010] In some embodiments, the first reinforcing member is disposed between the current collector and the diaphragm, and the side of the second reinforcing member facing the bend is mated to the side of the first reinforcing member.

[0011] In some embodiments, the first reinforcing member has a protruding edge on the edge region of the straight portion facing the cathode electrode, the protruding edge engaging with the cathode active material layer, and the side of the second reinforcing member facing the curved portion abutting the protruding edge. This ensures a firm and reliable bond between the first reinforcing member and the cathode active material layer, and by reducing the amount of cathode active material in this area, the number of electrons released from the cathode active material layer of the cathode electrode to the local area of ​​the anode electrode near the straight portion of the first reinforcing member can be reduced.

[0012] In some embodiments, the cathode electrode includes a current collector and cathode active material layers disposed on both sides of the current collector. A first reinforcing member is stacked with the cathode active material layers, and the thickness of the cathode active material layer in the portion stacked with the first reinforcing member is less than the thickness of the remaining portion. This reduces the amount of cathode active material in the cathode active material layer corresponding to the curved portion of the cathode electrode, thereby reducing the number of electrons released from the cathode active material layer corresponding to the curved portion of the cathode electrode to the local area of ​​the anode electrode near the first reinforcing member facing the straight portion. This reduces the likelihood of metal deposition in the local area of ​​the anode electrode near the first reinforcing member facing the straight portion of the second reinforcing member.

[0013] In some embodiments, the cathode electrode includes a current collector, the current collector having cathode active material layers on both sides of the flat portion, and the current collector having first reinforcing members on both sides of the curved portion, the first reinforcing members being connected to the cathode active material layers at both ends facing the flat portion.

[0014] In some embodiments, the first reinforcing member extends to the straight portion, thereby enabling the first reinforcing member to always cover the cathode or anode sheet of the entire curved portion, thereby providing a buffering effect against bending stress and reducing the possibility of the cathode active material layer of the cathode sheet or the anode active material layer of the anode sheet being bent and cracking and shedding powder. The projection of the second reinforcing member along the second direction is located within the projection of the straight portion.

[0015] In some embodiments, the second reinforcing member includes at least one of a mesh grid, a parallel line grid, and a wavy line grid.

[0016] In some embodiments, the second reinforcing member is any one of a polyimide structural member, an aramid structural member, an aramid nanofiber structural member, a polyvinyl alcohol structural member, or a polyethylene terephthalate structural member.

[0017] In some embodiments, the thickness of the second reinforcing member along the second direction is D, and the cathode electrode includes a current collector and cathode active material layers disposed on both sides of the current collector. The thickness of the cathode active material layers along the second direction is H, where 1 / 20 ≤ D / H ≤ 1 / 2. Thus, the second reinforcing member can achieve a good balance between providing the required reinforcement effect and minimizing electrical performance loss.

[0018] In some embodiments, the width of the second reinforcing member along the third direction is W1, and the width of the cathode active material layer along the third direction is W2, where W2-5mm≤W1≤W2, and the first direction, the second direction, and the third direction are perpendicular to each other. The second reinforcing member can support and balance the extrusion and shearing effects of metal dendrites, thereby reducing the possibility of metal dendrites extruding and damaging the diaphragm.

[0019] According to a second aspect of an embodiment of this application, a battery device is provided. The battery device includes a battery cell as described above, the battery cell being used to store or provide electrical energy.

[0020] According to a third aspect of the embodiments of this application, an electrical device is provided. The electrical device includes an electrical load; and: the electrical device further includes a plurality of battery cells as described above, the electrical load being electrically connected to the plurality of battery cells; or, the electrical device further includes a battery device as described above, the electrical load being electrically connected to the battery device. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a perspective view of a battery cell according to an embodiment of this application;

[0023] Figure 2 for Figure 1 A schematic diagram of the exploded battery cell is shown.

[0024] Figure 3 This is a cross-sectional schematic diagram of an assembly structure of the electrode assembly, the first reinforcing member, and the second reinforcing member of a battery cell according to an embodiment of this application;

[0025] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0026] Figure 5 This is a cross-sectional schematic diagram of an assembly structure of the electrode assembly, the first reinforcing member, and the second reinforcing member of a battery cell according to an embodiment of this application;

[0027] Figure 6 for Figure 5 Enlarged view of point B in the middle;

[0028] Figure 7 This is a cross-sectional schematic diagram of an assembly structure of the electrode assembly, the first reinforcing member, and the second reinforcing member of a battery cell according to an embodiment of this application;

[0029] Figure 8 for Figure 7 Enlarged view of point C in the middle;

[0030] Figure 9 This is a cross-sectional schematic diagram of an assembly structure of the electrode assembly, the first reinforcing member, and the second reinforcing member of a battery cell according to an embodiment of this application;

[0031] Figure 10 for Figure 9 Enlarged view of point D in the middle;

[0032] Figure 11 This is a cross-sectional schematic diagram of an assembly structure of the electrode assembly, the first reinforcing member, and the second reinforcing member of a battery cell according to an embodiment of this application;

[0033] Figure 12 for Figure 11 Enlarged view of point E in the middle;

[0034] Figure 13 This is a schematic diagram of a grid-like mesh formed by interlacing warp and weft threads in a battery cell according to an embodiment of this application;

[0035] Figure 14 This is a schematic diagram of another type of mesh grid formed by the interlacing of warp and weft threads in a battery cell according to an embodiment of this application;

[0036] Figure 15 This is a schematic diagram of the parallel-line grid of a battery cell according to an embodiment of this application;

[0037] Figure 16 This is a schematic diagram of the wavy wire mesh grid of a battery cell according to an embodiment of this application;

[0038] Figure 17 This is an exploded view of a battery device according to an embodiment of this application;

[0039] Figure 18 This is a schematic diagram of the structure of an electrical device according to an embodiment of this application.

[0040] The figures in the diagram are labeled as follows:

[0041] 100. Battery cell;

[0042] 10. Electrode assembly; 11. Cathode electrode; 111. Current collector; 112. Cathode active material layer; 12. Anode electrode; 13. Diaphragm; 131. First diaphragm layer; 132. Second diaphragm layer; 14. Straight section; 15. Bending section; 16. Tab;

[0043] 20. First reinforcing member; 21. Protruding edge;

[0044] 30. Second reinforcing component;

[0045] 41. Outer shell; 411. Inner cavity; 42. Top cover; 421. Pole post structure; 422. Pressure relief structure;

[0046] 50. Metallic dendrites;

[0047] 60. Mid-section face;

[0048] 200. Battery assembly; 201. Box body; 202. Box cover; 203. Assembly space;

[0049] 400. Electrical equipment; 410. Electrical load; 420. Control device; 430. Chassis; 440. Wheel;

[0050] X, first direction; Y, second direction; Z, third direction. Detailed Implementation

[0051] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0052] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0053] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0054] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction 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.

[0055] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants (battery devices used in these applications are generally referred to as energy storage batteries), but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields (battery devices used in these applications are generally referred to as power batteries). With the continuous expansion of the application fields of battery devices, market users are paying increasing attention to and demanding higher standards for the stability and reliability of battery devices.

[0056] In related technologies, the electrode assembly of a battery cell can be formed by winding. This winding process creates both straight and curved sections. During winding, the inner radius is compressed while the outer radius is stretched. Over time, metal dendrites can easily precipitate on the anode electrode in the curved section. These dendrites can compress and damage the separator, and subsequently, they can contact the cathode electrode, causing an internal short circuit within the battery cell. In severe cases, thermal runaway can occur, leading to a decrease in the stability and reliability of the battery cell.

[0057] Based on the above considerations, embodiments of this application provide a single battery cell. The electrode assembly of this battery cell is formed by winding a cathode electrode, an anode electrode, and a separator together, resulting in a straight portion and curved portions on both sides of the straight portion. In the curved portions, due to the different bending radii of the stacked cathode and anode electrodes at different layers, and because the radially inner side of each layer of cathode and anode electrodes in the curved portion is under bending compression and the radially outer side is under bending tension, bending stress exists on the cathode and anode electrodes in the curved portion. To address this, the electrode assembly of this battery cell includes a first reinforcing member, at least a portion of which is located in the curved portion. This first reinforcing member can reliably and stably function in the curved portion, providing a buffering effect against bending stress on the cathode and anode electrodes in the curved portion. This reduces the possibility of tearing of the cathode and anode electrodes in the curved portion (especially the radially outer sides of the cathode and anode electrodes in the curved portion), thereby reducing the likelihood of metal dendrite precipitation at the tear site. However, due to the physical property of insufficient negative electrode capacity in the local area of ​​the anode electrode near the straight portion of the first reinforcing member, metal will precipitate and accumulate on the side of the anode electrode facing the cathode electrode during long-term use of the battery cell, forming metal dendrites. The continuously growing metal dendrites will exert compressive and shear stress on the cathode electrode and the separator located between the anode and cathode electrodes, which will cause the cathode electrode to be squeezed and torn, puncturing the separator and overlapping with the metal dendrites, causing a short circuit, or the metal dendrites will damage the separator and overlap with the cathode electrode, causing a short circuit, resulting in battery cell failure or internal short circuit causing thermal runaway. To address this, the battery cell is provided with a second reinforcing member, which is located between the cathode electrode and the anode electrode. The second reinforcing member protrudes from the end of the first reinforcing member facing the straight portion along a first direction, and the side of the projection of the second reinforcing member along a second direction perpendicular to the first direction toward the curved portion is at least in contact with the side of the projection of the first reinforcing member. The second reinforcing member has pores connecting its two sides along the second direction to allow metal ions to pass through. Thus, the second reinforcing member can enhance the load-bearing capacity of the cathode electrode, such as tensile strength, tear resistance, and bending resistance, and can suppress cathode electrode breakage. Furthermore, the second reinforcing member can support and balance the extrusion and shearing effects of metal dendrites, thereby reducing the possibility of metal dendrites extruding and damaging the separator, which in turn reduces the possibility of metal dendrites overlapping the cathode electrode. This reduces the possibility of internal short circuits in the battery cell, reduces the possibility of thermal runaway, and improves the stability and reliability of the battery cell.

[0058] To illustrate the technical solutions provided by the embodiments of this application, the following detailed description is provided in conjunction with specific drawings and embodiments.

[0059] like Figures 1 to 3 , Figure 5 , Figure 7 , Figure 9 and Figure 11 As shown, the positive and negative directions of the X-axis are the first direction X, the positive and negative directions of the Y-axis are the second direction Y, and the positive and negative directions of the Z-axis are the third direction Z. And, as... Figure 3 , Figure 5 , Figure 7 , Figure 9 and Figure 11 The bisecting plane 60 shown refers to the plane that bisects the length of the electrode assembly 10 along the first direction X, wherein, Figure 5 , Figure 7 , Figure 9 and Figure 11 All are divided by the midpoint 60, with only one curved section 15 and a portion of the straight section 14 shown in the figure.

[0060] According to a first aspect of the embodiments of this application, embodiments of this application provide a battery cell 100, such as... Figure 1 and Figure 2 As shown. Figures 3 to 12 As shown, the battery cell 100 includes an electrode assembly 10, a first reinforcing member 20, and a second reinforcing member 30. The electrode assembly 10 includes a cathode electrode 11, an anode electrode 12, and a separator 13. The cathode electrode 11, separator 13, and anode electrode 12 are sequentially stacked and wound. The electrode assembly 10 is wound to form a straight portion 14 and curved portions 15 located on both sides of the straight portion 14. At least one layer of the first reinforcing member 20 is provided between the cathode electrode 11 and the separator 13. At least a portion of the first reinforcing member 20 is located in the curved portion 15. The second reinforcing member 30 is provided between the cathode electrode 11 and the separator 13. At least a portion of the second reinforcing member 30 extends along the first direction X in the straight portion 14. Wherein, with the second direction Y perpendicular to the first direction X as the projection direction, the side of the projection of the second reinforcing member 30 toward the curved portion 15 is at least connected to the side of the projection of the first reinforcing member 20.

[0061] In the battery cell 100 provided in the embodiments of this application, the electrode assembly 10 of the battery cell 100 is formed by sequentially stacking and winding a cathode electrode 11, a first separator 131, an anode electrode 12, and a second separator 132. That is, the separator 13 of the electrode assembly 10 includes a first separator 131 and a second separator 132, and the cathode electrode 11 is wound as the innermost layer, so that the electrode assembly 10 is wound to form a straight portion 14 and curved portions 15 located on both sides of the straight portion 14. In the curved portion 15, due to the layers The cathode plates 11 and anode plates 12 stacked together in different layers have different bending radii. Furthermore, since the radial inner side of each layer of cathode plates 11 and anode plates 12 in the bending section 15 is under bending compression and the radial outer side is under bending tension, the cathode plates 11 and anode plates 12 in the bending section 15 are subject to bending stress. This results in the possibility of tearing of the cathode plates 11 and anode plates 12 in the bending section 15 (especially the radial outer side of the cathode plate 11 and the radial outer side of the anode plate 12 in the bending section 15). In response, the electrode assembly 10 of the battery cell 100 is provided with a first reinforcing member 20. At least a portion of the first reinforcing member 20 is located in the bending portion 15. The first reinforcing member 20 can reliably and stably function in the bending portion 15, and provide a buffering effect for the cathode electrode 11 and anode electrode 12 of the bending portion 15 to withstand bending stress. This reduces the possibility of tearing of the cathode electrode 11 and anode electrode 12 of the bending portion 15 (especially the radial outer side of the cathode electrode 11 and the radial outer side of the anode electrode 12 in the bending portion 15), thereby reducing the possibility of metal dendrites 50 precipitating at the tear site. However, due to the physical property of insufficient negative electrode capacity in the local area of ​​the anode electrode 12 near the first reinforcing member 20 facing the straight portion 14, during the long-term use of the battery cell 100, metal will precipitate and accumulate on the side of the anode electrode 12 facing the cathode electrode 11 and form metal dendrites 50. The continuously accumulating and growing metal dendrites 50 will exert compressive and shear stress on the cathode electrode 11 and the separator 13 located between the anode electrode 12 and the cathode electrode 11, causing the cathode electrode 11 to be squeezed and torn, puncturing the separator 13 and overlapping with the metal dendrites, causing a short circuit. Alternatively, the metal dendrites 50 may damage the separator 13 and directly overlap with the cathode electrode 11, causing a short circuit, resulting in the failure of the battery cell 100, or even causing an internal short circuit and thermal runaway. To address this, the battery cell 100 is provided with a second reinforcing member 30, which is disposed between the cathode electrode 11 and the anode electrode 12. The second reinforcing member 30 protrudes from the end of the first reinforcing member 20 toward the straight portion 14 along the first direction X. Furthermore, the side of the second reinforcing member 30 projecting toward the curved portion 15 along the second direction Y perpendicular to the first direction X is at least in contact with the side of the first reinforcing member 20 projecting toward the second direction Y perpendicular to the first direction X. The second reinforcing member 30 is provided with pores connecting its two sides along the second direction Y to allow metal ions to pass through.Thus, the second reinforcing member 30 can enhance the tensile strength, tear resistance, and bending resistance of the cathode electrode 11, thereby suppressing the breakage of the cathode electrode 11. Furthermore, the second reinforcing member 30 can support and balance the extrusion and shearing action of the metal dendrites 50, thereby reducing the possibility of the metal dendrites 50 extruding and damaging the separator 13, which means reducing the possibility of the metal dendrites 50 overlapping the cathode electrode 11. This reduces the possibility of internal short circuit in the battery cell 100, reduces the possibility of thermal runaway, and improves the stability and reliability of the battery cell 100.

[0062] The aforementioned "physical property of insufficient negative electrode capacity in a local area of ​​the anode electrode 12 near the first reinforcing member 20 facing the straight portion 14" refers to the following: the reversible capacity of the local area of ​​the anode electrode 12 near the first reinforcing member 20 facing the straight portion 14 is less than the charging capacity of the cathode electrode 11. This results in the anode electrode 12 not being able to fully receive the lithium ions released from the cathode electrode 11 during charging, leading to a state of "lithium-rich cathode electrode 11 and lithium-poor anode electrode 12". Consequently, the potential of the anode electrode 12 cannot continue to decrease at the end of charging and is forced to drop to 0V (vs. Li / Li). + The following conditions trigger the deposition of metal (e.g., lithium plating). Furthermore, in this embodiment, the first reinforcing member 20 may be a dense sheet component without pores for metal ions to pass through, or the first reinforcing member 20 may be a component with pores for metal ions to pass through.

[0063] like Figures 5 to 12 As shown, the cathode electrode 11 includes a current collector 111 and cathode active material layers 112 disposed on both sides of the current collector 111. In preparing the cathode electrode 11, using the current collector 111 as a substrate, cathode active material is first coated on one side of the current collector 111 and then subjected to processes such as extrusion and drying, so that the coated cathode active material forms the first cathode active material layer 112. Then, the current collector 111 is flipped, and cathode active material is coated on the other side of the current collector 111, followed by processes such as extrusion and drying, to prepare the second cathode active material layer 112. Similarly, the anode electrode 12 includes a current collector and anode active material layers disposed on both sides of the current collector. In preparing the anode electrode 12, using the current collector as a substrate, anode active material is first coated on one side of the current collector and then subjected to processes such as extrusion and drying, so that the coated anode active material forms the first anode active material layer. Then, the current collector is flipped over, and an anode active material is coated on the other side of the current collector. The material is then subjected to processes such as extrusion and drying to form a second layer of anode active material.

[0064] In the embodiments of this application, the second reinforcing member 30 is disposed between the current collector 111 and the diaphragm 13.

[0065] In some embodiments, such as Figure 9 and Figure 10 As shown, the second reinforcing member 30 is embedded in the cathode active material layer 112, and the surface of the second reinforcing member 30 facing the anode electrode 12 is exposed and attached to the diaphragm 13. This arrangement of the second reinforcing member 30 and the cathode electrode 11 enhances the tensile strength, tear resistance, and bending resistance of the cathode electrode 11 without increasing its thickness along the second direction Y. Furthermore, this arrangement maintains the flatness of the cathode electrode 11, ensuring a smooth and consistent fit between the cathode electrode 11 and the diaphragm 13, preventing any abrupt changes in the bonding surface. Thus, the second reinforcing member 30 helps the diaphragm 13 support and balance the compressive and shear stress of the metal dendrites 50, reducing the possibility of the metal dendrites 50 compressing and damaging the diaphragm 13. The process of embedding the second reinforcing member 30 in the cathode active material layer 112 is integrated into the fabrication process of the formed cathode electrode 11, thereby improving fabrication efficiency. In the process of preparing the cathode active material layer 112 on one side of the current collector 111 of the formed cathode electrode 11, a layer of cathode active material is first coated on that side of the current collector 111. Then, a second reinforcing member 30 is placed at a predetermined position on this layer of cathode active material. Another layer of cathode active material with the same thickness as the second reinforcing member 30 is coated. Then, extrusion, drying and other processes are performed. In this way, the cathode active material layer 112 is formed and the second reinforcing member 30 is embedded in the cathode active material layer 112. Furthermore, since the second reinforcing member 30 is embedded in the cathode active material layer 112, the amount of cathode active material at its location can be reduced. Thus, when the battery cell 100 is used for charging and discharging, taking the release of electrons from the cathode electrode 11 to the anode electrode 12 as an example, since the second reinforcing member 30 reduces the amount of cathode active material at its location, it can reduce the number of electrons released from the cathode electrode 11 to the anode electrode 12 at that location to a certain extent. This reduces the possibility of metal precipitation in the local area of ​​the anode electrode 12 corresponding to the second reinforcing member 30 near the first reinforcing member 20 and towards the flat portion 14, that is, it reduces the possibility of metal dendrites 50 forming in the local area of ​​the anode electrode 12, thereby improving the stability and reliability of the battery cell 100.

[0066] In other embodiments, the second reinforcement 30 may be attached to the side surface of the cathode active material layer 112 facing away from the current collector 111, in which case the diaphragm 13 covers the second reinforcement 30.

[0067] Taking the release of electrons from the cathode electrode 11 to the anode electrode 12 as an example, in order to further reduce the number of electrons released from the cathode electrode 11 to the local area of ​​the anode electrode 12 near the first reinforcing member 20 towards the straight portion 14, in some embodiments, the first reinforcing member 20 is stacked with the cathode active material layer 112, and the thickness of the cathode active material layer 112 in the portion stacked with the first reinforcing member 20 is less than the thickness of the remaining portion of the cathode active material layer 112. That is, the first reinforcing member 20 is embedded in the cathode active material layer 112, thereby reducing the amount of cathode active material in the cathode active material layer 112 of the cathode electrode 11 corresponding to the bent portion 15. This reduces the number of electrons released from the cathode active material layer 112 of the cathode electrode 11 corresponding to the bent portion 15 to the local area of ​​the anode electrode 12 near the first reinforcing member 20 towards the straight portion 14. In other words, this reduces the likelihood of metal precipitation in the local area of ​​the anode electrode 12 near the first reinforcing member 20 and facing the straight portion 14, corresponding to the second reinforcing member 30. This also reduces the possibility of metal dendrites 50 forming in this local area of ​​the anode electrode 12, thereby improving the stability and reliability of the battery cell 100. Furthermore, the first reinforcing member 20 is embedded in the cathode active material layer 112, which reduces (or even eliminates) the formation of a step between the side of the first reinforcing member 20 facing the straight portion 14 and the surface of the cathode electrode 11. This reduces the compressive and shear stress exerted by the metal dendrites 50 on the separator 13, reducing the possibility of the metal dendrites 50 compressing and damaging the separator 13. This also reduces the possibility of the metal dendrites 50 directly contacting the cathode electrode, thereby reducing the possibility of internal short circuits and thermal runaway in the battery cell 100, and improving the stability and reliability of the battery cell 100.

[0068] In some embodiments, the current collector 111 has cathode active material layers 112 on both sides of the flat portion 14, and first reinforcing members 20 are provided on both sides of the curved portion 15. The first reinforcing members 20 are abutted against the cathode active material layers 112 at both ends facing the flat portion 14. In this embodiment, if the cathode electrode 11 is flattened and straightened, the cathode active material layers 112 on the surface of the current collector 111 are distributed in segments at intervals, and a first reinforcing member 20 is provided between adjacent segments. That is, multiple segments of cathode active material layers 112 and multiple first reinforcing members 20 are alternately distributed on the surface of the current collector 111. Furthermore, the first reinforcing members 20 in this embodiment are dense sheet components without pores for metal ions to pass through. This reduces the metal ions transferred to the anode electrode 12, lowering the possibility of metal dendrite formation.

[0069] In the electrode assembly 10 of the battery cell 100 of this application, the projection of the first reinforcing member 20 toward the side of the straight portion 14 along the second direction Y can be an overlap of the projection along the second direction Y at the connection between the curved portion 15 and the straight portion 14 (this projection is a line segment, and the corresponding projection of the side of the first reinforcing member 20 is also a line segment, and the two line segments overlap). Alternatively, the first reinforcing member 20 extends to the straight portion 14, that is, the first reinforcing member 20 covers the cathode electrode 11 and anode electrode 12 of the curved portion 15. In this way, the first reinforcing member 20 plays a buffering role in bearing bending stress on the cathode electrode 11 and anode electrode 12 of the entire curved portion 15, thereby reducing the possibility of tearing of the cathode electrode 11 and anode electrode 12 of the curved portion 15 (especially the radially outer side of the cathode electrode 11 and the radially outer side of the anode electrode 12 in the curved portion 15), thereby reducing the possibility of metal dendrites 50 precipitating at the tear site. However, during the winding process, due to factors such as process errors in the winding process and / or assembly dimensional errors in the installation of the first reinforcing member 20 on the cathode electrode 11, the sides of the multi-layered first reinforcing members 20 facing the straight portion 14 in the electrode assembly 10 are prone to misalignment in the first direction X. This results in some first reinforcing members 20 not covering the entire cathode electrode 11 and anode electrode 12 of the curved portion 15. To address this, in the embodiments of this application, the first reinforcing member 20 extends to the straight portion 14, thereby ensuring that the first reinforcing member 20 always covers the entire cathode electrode 11 and anode electrode 12 of the curved portion 15, providing a buffering effect against bending stress for the entire cathode electrode 11 and anode electrode 12 of the curved portion 15. Furthermore, the projection of the second reinforcing member 30 along the second direction Y is located within the projection of the straight portion 14 along the second direction Y, ensuring that the second reinforcing member 30 is always located within the straight portion 14 of the wound electrode assembly 10.

[0070] When the side of the multilayer first reinforcing member 20 facing the straight portion 14 in the electrode assembly 10 is misaligned in the first direction X, and when the side of the first reinforcing member 20 facing the straight portion 14 forms a step with the surface of the cathode electrode 11, the compressive shear stress exerted on the separator 13 by the metal dendrites 50 precipitated in the local area of ​​the anode electrode 12 near the straight portion 14 of the first reinforcing member 20 becomes more pronounced. To address this, the second reinforcing member 30 enhances the tensile strength, tear resistance, and bending resistance of the cathode electrode 11, and supports and balances the compressive shear effect of the metal dendrites 50, thereby reducing the possibility of the metal dendrites 50 compressing and damaging the separator 13, i.e., reducing the possibility of the metal dendrites 50 directly contacting the cathode electrode, thus reducing the possibility of internal short circuits in the battery cell 100, reducing the possibility of thermal runaway, and improving the stability and reliability of the battery cell 100.

[0071] In some embodiments, the first reinforcing member 20 is disposed between the current collector 111 and the diaphragm 13, and the second reinforcing member 30 is also disposed between the current collector 111 and the diaphragm 13, such as... Figure 5 , Figure 6 , Figure 9 and Figure 10 As shown, the side of the second reinforcing member 30 facing the bend 15 is mated with the side of the first reinforcing member 20. In other embodiments, such as Figure 7 and Figure 8 The projection of the second reinforcing member 30 along the second direction Y overlaps with the projection of the first reinforcing member 20 along the second direction Y. In other words, the aforementioned "the side of the projection of the second reinforcing member 30 along the second direction Y toward the curved portion 15 is at least in contact with the side of the projection of the first reinforcing member 20" includes the following two possibilities: First, the side of the projection of the second reinforcing member 30 along the second direction Y toward the curved portion 15 is in contact with the side of the projection of the first reinforcing member 20; second, the projection of the second reinforcing member 30 along the second direction Y and the projection of the first reinforcing member 20 along the second direction Y partially overlap, i.e., the aforementioned overlapping area. The second reinforcing member 30 enhances the tensile strength, tear resistance, and bending resistance of the cathode electrode 11, thus suppressing its breakage. Furthermore, the second reinforcing member 30 supports and balances the extrusion and shearing action of the metal dendrites 50, thereby reducing the possibility of the metal dendrites 50 extruding and damaging the separator 13, which in turn reduces the possibility of the metal dendrites 50 directly contacting the cathode electrode. This reduces the possibility of internal short circuits in the battery cell 100, reduces the possibility of thermal runaway, and improves the stability and reliability of the battery cell 100.

[0072] In some embodiments, the overlapping area between the projection of the second reinforcing member 30 of the electrode assembly 10 of the battery cell 100 along the second direction Y and the projection of the first reinforcing member 20 along the second direction Y is substantially concentrated in the straight portion 14, and, as Figure 8As shown, the length of the overlapping region along the first direction X is L, 50μm≤L≤5mm. The length L of the overlapping region along the first direction X can be 50μm, 100μm, 150μm, 200μm, 300μm, 500μm, 800μm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm. Thus, during charging and discharging, even if the cathode electrode 11 of the electrode assembly 10 of the battery cell 100 expands and stretches, the second reinforcing member 30 can always play a role in strengthening and supporting it. This reduces the possibility of a gap region appearing between the second reinforcing member 30 and the first reinforcing member 20 when the cathode electrode 11 expands and stretches. It also reduces the possibility of the compressive shear stress applied by the metal dendrites 50 acting on this gap region, thereby reducing the possibility of the metal dendrites 50 compressing and damaging the separator 13. In other words, it reduces the possibility of the metal dendrites 50 directly contacting the cathode electrode, thereby reducing the possibility of internal short circuit in the battery cell 100, reducing the possibility of thermal runaway, and improving the stability and reliability of the battery cell 100.

[0073] As an example, the length L of the overlapping region along the first direction X between the projection of the second reinforcing member 30 along the second direction Y and the projection of the first reinforcing member 20 along the second direction Y can preferably be set to 500μm≤L≤2mm. Further, the length L of the overlapping region along the first direction X between the projection of the second reinforcing member 30 along the second direction Y and the projection of the first reinforcing member 20 along the second direction Y can be set to 0.5mm≤L≤2mm.

[0074] like Figure 11 and Figure 12As shown, in some embodiments, the first reinforcing member 20 has a protruding edge 21 facing the edge region of the straight portion 14 toward the cathode electrode 11, and the protruding edge 21 engages with the cathode active material layer 112. In this embodiment, the engagement of the protruding edge 21 with the cathode active material layer 112 makes the first reinforcing member 20 and the cathode active material layer 112 firmly and reliably bonded. Thus, during the winding and forming of the electrode assembly 10, the first reinforcing member 20 can more persistently and reliably function stably in the bending portion 15, providing a buffering effect against bending stress on the cathode electrode 11 and anode electrode 12 of the bending portion 15, thereby reducing the possibility of tearing of the cathode electrode 11 and anode electrode 12 of the bending portion 15 (especially the radially outer side of the cathode electrode 11 and the radially outer side of the anode electrode 12 in the bending portion 15), thereby reducing the possibility of metal dendrites 50 precipitating at the tear site. Furthermore, since the protruding edge 21 engages with the cathode active material layer 112, the amount of cathode active material at this location is reduced. When the battery cell 100 is used for charging and discharging, taking the release of electrons from the cathode electrode 11 to the anode electrode 12 as an example, the number of electrons released from this location of the cathode electrode 11 to the anode electrode 12 can be reduced to a certain extent. This reduces the possibility of metal precipitation in the local area of ​​the anode electrode 12 corresponding to the second reinforcing member 30 near the first reinforcing member 20 towards the straight portion 14, that is, it reduces the possibility of metal dendrites 50 forming in this local area of ​​the anode electrode 12, thereby improving the stability and reliability of the battery cell 100. In this embodiment, the side of the second reinforcing member 30 facing the curved portion 15 is mated with the protruding edge 21.

[0075] In some embodiments, the second reinforcing member 30 includes: Figure 13 , Figure 14 The grid-like mesh shown, such as Figure 15 The parallel line grid shown, such as Figure 16 At least one of the wavy wire mesh grids shown. In this embodiment, the second reinforcing member 30 preferably employs a mesh grid or a wavy wire mesh grid. The mesh grid can disperse the compressive shear stress it receives, preventing stress concentration on a single grid line and thus preventing crack propagation. The mesh structure allows the cathode active material slurry to fully penetrate, forming a strong mechanical interlock with the cathode active material layer 112, enhancing interfacial adhesion and preventing detachment. The pore size ranges from 20μm to 500μm, preferably from 20μm to 100μm. The mesh grid achieves maximum reinforcement coverage with minimal material usage. The wavy wire mesh grid can expand and contract like a spring, better absorbing the expansion / contraction stress of the electrode during cycling and buffering damage caused by volume changes.

[0076] In some embodiments, the second reinforcing member 30 is any one of a polyimide structural member, an aramid structural member, an aramid nanofiber structural member, a polyvinyl alcohol structural member, and a polyethylene terephthalate structural member. Specifically: the polyimide structural member is a component molded from polyimide material (i.e., PI material, PI is short for Polyimide); the aramid structural member is a component molded from aramid material (i.e., Aramid); the aramid nanofiber structural member is a component molded from aramid nanofiber material (i.e., ANF material, ANF is short for aramid nanofibers); the polyvinyl alcohol structural member is a component molded from polyvinyl alcohol material (i.e., PVA material, PVA is short for Polyvinyl Alcohol); and the polyethylene terephthalate structural member is a component molded from polyethylene terephthalate material (i.e., PET material, PET is short for Polyethylene terephthalate). In this embodiment, the second reinforcing member 30 is a component made of insulating material. Thus, even if the cathode electrode 11 is torn by shear stress and the break of the current collector 111 is warped or the metal dendrites pierce the diaphragm 13 (taking the second reinforcing member 30 being located between the current collector 111 and the diaphragm 13 as an example), the second reinforcing member 30 can block the break of the current collector 111 or block the metal dendrites, thereby preventing the break of the current collector 111 from overlapping with the anode electrode 12 or preventing the metal dendrites from overlapping with the current collector 111 of the cathode electrode 11, thus preventing internal short circuits that could lead to thermal runaway.

[0077] In this application, the second reinforcing member 30 is preferably a polyimide structural member or an aramid structural member. Polyimide structural members can withstand temperatures above 400°C, are fully compatible with electrode baking processes, do not deform or degrade, and possess extremely high tensile strength and modulus, providing better reinforcement. They are also stable within the 100V operating voltage range of the battery cell, do not participate in side reactions, and ensure service life. Aramid structural members, while providing reinforcement, are lighter in weight, have less impact on energy density, can cope with the bending deformation of the bending portion 15 during winding, and have excellent fatigue resistance. That is, even if the aramid structural member extends to the bending portion 15, it can still withstand the bending stress caused by winding and undergo adaptive deformation.

[0078] In some embodiments, such as Figure 10 As shown, the thickness of the second reinforcing member 30 along the second direction Y is D. The cathode electrode 11 includes a current collector 111 and cathode active material layers 112 disposed on both sides of the current collector 111. The thickness of the cathode active material layer 112 along the second direction Y is H, and 1 / 20 ≤ D / H ≤ 1 / 2. In this way, the second reinforcing member 30 can achieve a good balance between providing the required reinforcement effect and minimizing electrical performance loss.

[0079] In some embodiments, such as Figure 2 , Figures 13 to 16 As shown, the width of the second reinforcing member 30 along the third direction Z is W1, and the width of the cathode active material layer 112 along the third direction Z is W2, where W2-5mm≤W1≤W2. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other. When W1<W2, the distance between the two ends of the second reinforcing member 30 along the third direction Z and the corresponding ends of the cathode active material layer 112 along the third direction Z is equal. That is, along the third direction Z, the second reinforcing member 30 is centrally located on the cathode active material layer 112. This allows the second reinforcing member 30 to better support and balance the extrusion and shearing action of the metal dendrites 50, thereby reducing the possibility of the metal dendrites 50 extruding and damaging the diaphragm 13. In a preferred embodiment of this application, the width of the second reinforcing member 30 along the third direction Z is equal to the width of the cathode active material layer 112 along the third direction Z, i.e., W1=W2. Thus, regardless of where the metal dendrites 50 precipitate in the local area of ​​the anode electrode 12 near the first reinforcing member 20 toward the straight portion 14 along the third direction Z, the second reinforcing member 30 can support and balance the extrusion and shearing effect of the metal dendrites 50, thereby reducing the possibility of the metal dendrites 50 extruding and damaging the diaphragm 13.

[0080] like Figure 1 and Figure 2 As shown, the battery cell 100 provided in the embodiments of this application further includes a housing 41 and a top cover 42. The housing 41 has a receiving cavity 411 for accommodating the electrode assembly 10, and the top cover 42 is provided with a terminal post structure 421 and a pressure relief structure 422. After the electrode assembly 10 is formed by winding, the tabs 16 of the electrode assembly 10 are electrically connected to the terminal post structure 421, and then the electrode assembly 10 is installed into the receiving cavity 411. Next, the top cover 42 is closed onto the open end of the housing 41, and the gap between the housing 41 and the top cover 42 is sealed. The battery cell 100 in the embodiments of this application can be a secondary battery, which refers to a battery cell 100 that can be recharged after discharge to activate the active materials and continue to be used. The battery cell 100 can 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 the embodiments of this application are not limited to this. Furthermore, the battery cell 100 provided in the embodiments of this application is a square battery cell, also known as a square cell.

[0081] According to a second aspect of the embodiments of this application, embodiments of this application also provide a battery device 200, such as... Figure 17As shown, the battery device 200 includes a main body 201, a cover 202, and battery cells 100 as described above. The cover 202 closes onto the open end of the main body 201, forming an assembly space 203. Multiple battery cells 100 are arrayed and assembled within the assembly space 203. The battery cells 100 are used for storing electrical energy or supplying power.

[0082] According to a third aspect of the embodiments of this application, embodiments of this application also provide an electrical device 400, which includes an electrical load 410.

[0083] Electrical equipment 400 includes, but is not limited to, electric toys, power tools, electric vehicles, electric cars, ships, and spacecraft. Electric toys may include, but are not limited to, stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft may include, but are not limited to, airplanes, rockets, space shuttles, and spacecraft.

[0084] In some embodiments, the electrical device 400 further includes a battery device 200 as described above, i.e., the electrical device 400 employs one battery device 200 or multiple battery devices 200 connected in series, parallel, or mixed connections, and the electrical load 410 is electrically connected to the battery device 200. The battery device 200 is used to store electrical energy, or the battery device 200 is used to provide electrical energy to the electrical load 410, thereby enabling the electrical load 410 to operate normally.

[0085] Alternatively, in some other embodiments of this application, the electrical device 400 further includes battery cells 100 as described above. That is, the electrical device 400 uses multiple battery cells 100 connected in series, parallel, or in a mixed configuration, and the electrical load 410 is electrically connected to the multiple battery cells 100. The multiple battery cells 100 are used to store electrical energy, or to provide electrical energy to the electrical load 410, thereby enabling the electrical load 410 to operate normally.

[0086] Among them, the electrical equipment 400 is an electric vehicle, and it is assembled using a battery device 200, such as Figure 18As shown, the battery device 200 is mounted on the frame 430 of the electric vehicle. The electric vehicle includes the frame 430, a drive motor, and wheels 440. The battery device 200 and the drive motor are both fixedly mounted on the frame 430, and the wheels 440 are rotatably connected to the frame 430. The battery device 200 is electrically connected to the drive motor, and the drive motor is driven by the wheels 440. When the battery device 200 provided in this application supplies power to the drive motor (the drive motor is one of the electrical loads 410 of the electrical equipment 400), the drive motor drives the wheels 440 to rotate, enabling the electric vehicle to drive normally. Furthermore, the electric vehicle includes a control device 420, which is mounted on the frame 430 and electrically connected to the battery device 200. The control device 420 is used to control and monitor the charging and discharging status of the battery device 200. In some electric vehicles, the battery housing of the battery device 200 can be part of the chassis structure of the electric vehicle. For example, a portion of the battery box can be at least part of the floor of the electric vehicle, or a portion of the battery box can be at least part of the crossbeams and longitudinal beams of the electric vehicle.

[0087] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements 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: An electrode assembly includes a cathode electrode, an anode electrode, and a diaphragm, wherein the cathode electrode, the diaphragm, and the anode electrode are sequentially stacked and wound together, and the electrode assembly is wound to form a straight portion and curved portions located on both sides of the straight portion; A first reinforcing member, at least a portion of which is located in the bent portion, and at least one layer of the first reinforcing member is provided between adjacent cathode plates and anode plates; The second reinforcing member is disposed between the cathode electrode and the anode electrode. The second reinforcing member protrudes from the end of the first reinforcing member facing the straight portion along a first direction. The projection direction is a second direction perpendicular to the first direction. The side of the projection of the second reinforcing member facing the curved portion is at least connected to the side of the projection of the first reinforcing member. The second reinforcing member is provided with a hole connecting its two sides along the second direction.

2. The battery cell according to claim 1, characterized in that, The cathode electrode includes a current collector and a cathode active material layer disposed on both sides of the current collector, and the second reinforcing member is disposed between the current collector and the diaphragm.

3. The battery cell according to claim 2, characterized in that, The second reinforcing member is attached to the side of the cathode active material layer opposite to the current collector; Alternatively, the second reinforcing member may be embedded in the cathode active material layer.

4. The battery cell according to any one of claims 1-3, characterized in that, The projection of the second reinforcing member along the second direction overlaps with the projection of the first reinforcing member along the second direction.

5. The battery cell according to claim 4, characterized in that, The length of the overlapping region along the first direction is L, where 50μm≤L≤5mm.

6. The battery cell according to claim 2 or 3, characterized in that, The first reinforcing member is disposed between the current collector and the diaphragm, and the side of the second reinforcing member facing the curved portion is mated with the side of the first reinforcing member.

7. The battery cell according to claim 6, characterized in that, The first reinforcing member has a protruding edge facing the edge region of the straight portion toward the cathode electrode, and the protruding edge engages with the cathode active material layer. The second reinforcing member is disposed with the protruding edge on the side of the curved portion.

8. The battery cell according to claim 1, characterized in that, The cathode electrode includes a current collector and cathode active material layers disposed on both sides of the current collector. The first reinforcing member is stacked with the cathode active material layers, and the thickness of the cathode active material layer in the portion stacked with the first reinforcing member is less than the thickness of the cathode active material layer in the remaining portion. Alternatively, the cathode electrode includes a current collector, the current collector having the cathode active material layer on both sides of the straight portion, the current collector having the first reinforcing member on both sides of the curved portion, and the first reinforcing member having the cathode active material layer at both ends facing the straight portion.

9. The battery cell according to claim 1, characterized in that, The first reinforcing member extends to the straight portion, and the projection of the second reinforcing member along the second direction is located within the projection of the straight portion.

10. The battery cell according to claim 1, characterized in that, The second reinforcing member includes at least one of a mesh grid, a parallel line grid, and a wavy line grid.

11. The battery cell according to claim 10, characterized in that, The second reinforcing member is any one of the following: polyimide structural member, aramid structural member, aramid nanofiber structural member, polyvinyl alcohol structural member, and polyethylene terephthalate structural member.

12. The battery cell according to claim 2, characterized in that, The thickness of the second reinforcing member is D, and the thickness of the cathode active material layer is H, where 1 / 20 ≤ D / H ≤ 1 / 2.

13. The battery cell according to claim 12, characterized in that, The width of the second reinforcing member along the third direction is W1, and the width of the cathode active material layer along the third direction is W2, where W2-5mm≤W1≤W2, and the first direction, the second direction, and the third direction are perpendicular to each other.

14. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-13.

15. An electrical appliance, characterized in that, The electrical equipment includes a plurality of battery cells as described in any one of claims 1-13; Alternatively, the electrical device may include the battery device as described in claim 14.

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