Cylindrical battery and electric device

Abstract

A cylindrical battery (100) and an electric device (200). The cylindrical battery (100) comprises a casing (10), and an electrode assembly (20) and a current collecting disc (30) which are arranged in the casing (10). The electrode assembly (20) is formed by stacking a first electrode sheet (21), a separator (23) and a second electrode sheet (22) and then winding same, and in the winding direction of the electrode assembly (20), the first electrode sheet (21) comprises a first portion (211) and a second portion (212) connected to each other, the first portion (211) comprising a winding start section of the first electrode sheet (21). In the axial direction (X) of the cylindrical battery (100), the end face of the first portion (211) extends beyond the end face of the second portion (212). The electrode assembly (20) comprises a body part (24) and a flattened part (25) connected to each other, the body part (24) and the flattened part (25) being arranged in the axial direction (X), and the flattened part (25) being located at the portion of the first portion (211) extending beyond the second portion (212). The electrode assembly (20) and the current collecting disc (30) are arranged in the axial direction (X), and the current collecting disc (30) is connected to the flattened part (25). The diameter of the body part (24) is defined as D1, the diameter of the flattened part (25) is defined as D2, and D2<D1.

Description

Cylindrical batteries and electrical equipment Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a cylindrical battery and electrical equipment. Background Art

[0002] In cylindrical batteries, the ends of the electrode assemblies are usually flattened to connect to the current collecting plates. The flattened parts of the electrode sheets take up more space, resulting in a longer length of the electrode assembly, which affects the energy density of the cylindrical battery.

[0003] Summary of the Invention

[0004] In view of the above situation, it is necessary to provide a cylindrical battery to reduce the length of its internal battery cell components and improve the energy density of the cylindrical battery.

[0005] An embodiment of the present application provides a cylindrical battery, comprising a shell, an electrode assembly arranged in the shell, and a current collecting disk. The electrode assembly is formed by stacking and winding a first pole piece, a diaphragm, and a second pole piece, and the diaphragm is arranged between the first pole piece and the second pole piece. Along the winding direction of the electrode assembly, the first pole piece includes a first part and a second part that are connected to each other, and the first part includes a winding starting section of the first pole piece. Along the axial direction of the cylindrical battery, the end face of the first part exceeds the end face of the second part. The electrode assembly includes a main body and a flattened part that are connected to each other, and the main body and the flattened part are arranged in the axial direction. The flattened part is located in the part where the first part exceeds the second part, and along the axial direction, the flattened part exceeds the main body. The electrode assembly and the current collecting disk are arranged in the axial direction, and the current collecting disk is connected to the flattened part. The diameter of the main body is defined as D1, and the diameter of the flattened part is defined as D2, and D2 is less than D1.

[0006] In the above-mentioned cylindrical battery, the first part of the first pole piece extends axially beyond the second part, and the part of the first part extending beyond the second part forms a flattened part of the electrode assembly, and the diameter D2 of the flattened part is smaller than the diameter D1 of the main body. Compared with the electrode assembly in which the main body and the flattened part have equal diameters, the electrode assembly of the present application has a smaller end in the axial direction, which is convenient for compressing the flattened part and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly and improving the energy density of the cylindrical battery. At the same time, the first part is located at the starting section of the winding of the electrode assembly, so that the flattened part is denser after compression, which is convenient for connecting the current collecting plate and improving the current flow capacity between the first pole piece and the current collecting plate, thereby reducing the temperature rise.

[0007] In some embodiments of the present application, D1-D2 ≥ 3 mm, which is beneficial to compressing the flattened portion, reducing the length of the electrode assembly, and improving the energy density of the cylindrical battery. It is also beneficial to ensure the connection area between the flattened portion and the current collecting plate, and improve the current flow capacity between the electrode assembly and the current collecting plate.

[0008] In some embodiments of the present application, 13 mm ≤ D2 ≤ 40 mm, which is beneficial to further ensure the connection area between the flattened portion and the current collecting disk, and further improve the current flow capacity between the electrode assembly and the current collecting disk.

[0009] In some embodiments of the present application, the cylindrical battery further includes a first insulating member disposed within the housing, with the main body and the first insulating member arranged axially. When viewed in the reverse direction of the axial direction, the first insulating member surrounds the flattened portion. In the radial direction of the cylindrical battery, the projection of the first insulating member overlaps with the projection of the flattened portion. The first insulating member not only provides insulation protection, reducing the risk of short circuits in the electrode assembly, but also serves as a filler, reducing the risk of axial upward movement of the electrode assembly and improving the safety of the cylindrical battery.

[0010] In some embodiments of the present application, the thickness of the first insulating member is defined as H along the axial direction, 0.2mm≤H≤1mm, which is conducive to the first insulating member playing the role of insulation and filling protection, improving the safety performance of the cylindrical battery, and at the same time, it will not take up too much space, reducing the impact on the energy density of the cylindrical battery.

[0011] In some embodiments of the present application, the first pole piece includes a first current collector, a first insulating layer and a first active layer. The first insulating layer and the first active layer are both arranged on the same surface of the first current collector, and the first active layer and the first insulating layer are arranged axially.

[0012] In some embodiments of the present application, the first current collector includes a hollow foil region, where the first insulating layer and the first active layer are not provided. The first active layer, the first insulating layer, and the hollow foil region are arranged axially. A portion of the hollow foil region is flattened to form a flattened portion to facilitate connection between the first electrode sheet and the current collector plate.

[0013] In some embodiments of the present application, the distance between the end surface of the flattened portion and the first insulating layer is defined as L1 along the axial direction, 0.5mm≤L1≤1mm, which is beneficial to reducing the axial length of the electrode assembly and improving the energy density of the cylindrical battery.

[0014] In some embodiments of the present application, the first insulating layer is closer to the current collector than the first active layer, with a portion of the first insulating layer located in the first portion and a portion of the first insulating layer located in the second portion. The first insulating layer is located at the axial end of the second portion, which helps to cover and protect burrs of the first current collector at the end of the second portion, reducing the risk of puncturing the diaphragm by such burrs and improving the safety performance of the cylindrical battery.

[0015] In some embodiments of the present application, along the axial direction, the width of the first insulating layer in the first portion is determined to be W1, the width of the first insulating layer in the second portion is determined to be W2, and W1>W2.

[0016] In some embodiments of the present application, the current collecting tray includes a main portion and an extension portion that are interconnected. The main portion and the extension portion are stacked axially, with the main portion connected to the flattened portion, and the extension portion connected to the terminal post or cover of the cylindrical battery. The current collecting tray is designed as a two-layer structure, which helps reduce the height space it occupies and improve the energy density of the cylindrical battery.

[0017] In some embodiments of the present application, along the radial direction of the cylindrical battery, the maximum length of the current collecting disk after unfolding is defined as L2, 1.5≤L2 / D1≤2, which is beneficial to reducing the number of layers of the current collecting disk after folding, reducing the height space it occupies, and improving the energy density of the cylindrical battery.

[0018] In some embodiments of the present application, along the axial direction, the end of the first portion away from the current collecting disk is the first end, and the end of the second portion away from the current collecting disk is the second end. In the direction opposite to the axial direction, the first end does not exceed the second end.

[0019] An embodiment of the present application further provides an electrical device comprising the cylindrical battery of any of the aforementioned embodiments.

[0020] In the above-mentioned electrical equipment, the first part of the first electrode sheet in the cylindrical battery extends axially beyond the second part, and the part where the first part extends beyond the second part forms a flattened part of the electrode assembly, and the diameter D2 of the flattened part is smaller than the diameter D1 of the main body. Compared with the electrode assembly in which the main body and the flattened part have equal diameters, the end of the electrode assembly of the present application is smaller in the axial direction, which is convenient for compressing the flattened part and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly, improving the energy density of the cylindrical battery, and reducing the impact of the energy density of the cylindrical battery on the electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic structural diagram of a cylindrical battery in one embodiment of the present application.

[0022] FIG2 is a cross-sectional view of a cylindrical battery in one embodiment of the present application.

[0023] FIG3 is a schematic structural diagram of the first pole piece in an expanded state in one embodiment of the present application.

[0024] FIG4 is a schematic structural diagram of an electrode assembly in one embodiment of the present application.

[0025] FIG5 is a front view of an electrode assembly according to an embodiment of the present application.

[0026] FIG6 is a cross-sectional view of a portion of an electrode assembly according to an embodiment of the present application.

[0027] FIG7 is an exploded view of a portion of the cylindrical battery structure in one embodiment of the present application.

[0028] FIG8 is a schematic structural diagram of a current collecting plate in an expanded state in one embodiment of the present application.

[0029] FIG9 is a schematic diagram of the three-dimensional structure of the current collecting plate in an expanded state in one embodiment of the present application.

[0030] FIG10 is a schematic structural diagram of a current collecting plate in a bent state in one embodiment of the present application.

[0031] FIG11 is a schematic structural diagram of an electrical device in an embodiment of the present application.

[0032] Description of the main component symbols Cylindrical battery 100 Housing 10 Side wall 11 Bottom wall 12 Electrode assembly 20 First pole piece 21 First portion 211 Second portion 212 First current collector 214 First insulating layer 215 First active layer 216 Hollow foil area 217 Second pole piece 22 Second current collector 221 Separator 23 Main body 24 Flattened portion 25 End surface 251 Current collecting plate 30 Base material 31 Extension 32 Bending line 33 End cap 40 Explosion-proof disk 50 Groove 51 Orifice plate 60 Through hole 61 Structural component70 First insulating member 81 Second insulating member 82 Axial X Electrical equipment 200

[0033] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0035] It should be noted that when an element is considered to be “connected” to another element, it may be directly connected to the other element or there may be a centrally disposed element. When an element is considered to be “disposed on” another element, it may be directly disposed on the other element or there may be a centrally disposed element.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0037] An embodiment of the present application provides a cylindrical battery, comprising a shell, an electrode assembly arranged in the shell, and a current collecting disk. The electrode assembly is formed by stacking and winding a first pole piece, a diaphragm, and a second pole piece, and the diaphragm is arranged between the first pole piece and the second pole piece. Along the winding direction of the electrode assembly, the first pole piece includes a first part and a second part that are connected to each other, and the first part includes a winding starting section of the first pole piece. Along the axial direction of the cylindrical battery, the end face of the first part exceeds the end face of the second part. The electrode assembly includes a main body and a flattened part that are connected to each other, and the main body and the flattened part are arranged in the axial direction. The flattened part is located in the part where the first part exceeds the second part, and along the axial direction, the flattened part exceeds the main body. The electrode assembly and the current collecting disk are arranged in the axial direction, and the current collecting disk is connected to the flattened part. The diameter of the main body is defined as D1, and the diameter of the flattened part is defined as D2, and D2 is less than D1.

[0038] In the above-mentioned cylindrical battery, the first part of the first pole piece extends axially beyond the second part, and the part of the first part extending beyond the second part forms a flattened part of the electrode assembly, and the diameter D2 of the flattened part is smaller than the diameter D1 of the main body. Compared with the electrode assembly in which the main body and the flattened part have equal diameters, the electrode assembly of the present application has a smaller end in the axial direction, which is convenient for compressing the flattened part and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly and improving the energy density of the cylindrical battery. At the same time, the first part is located at the starting section of the winding of the electrode assembly, so that the flattened part is denser after compression, which is convenient for connecting the current collecting plate and improving the current flow capacity between the first pole piece and the current collecting plate, thereby reducing the temperature rise.

[0039] The embodiments of the present application are further described below with reference to the accompanying drawings.

[0040] As shown in FIG. 1 to FIG. 5 , an embodiment of the present application provides a cylindrical battery 100 , including a housing 10 , an electrode assembly 20 disposed in the housing 10 , and a current collecting plate 30 .

[0041] The electrode assembly 20 is formed by stacking and winding a first electrode sheet 21, a separator 23, and a second electrode sheet 22, with the separator 23 being disposed between the first electrode sheet 21 and the second electrode sheet 22. Along the winding direction of the electrode assembly 20, the first electrode sheet 21 includes a first portion 211 and a second portion 212 connected to each other, and the first portion 211 includes a winding starting section of the first electrode sheet 21. Along the axial direction X of the cylindrical battery 100, the end face of the first portion 211 exceeds the end face of the second portion 212. The winding starting section of the first electrode sheet 21 refers to the portion of the first electrode sheet 21 in the wound electrode assembly 20 that starts from the starting end of the first electrode sheet 21 and extends a distance along the winding direction of the electrode assembly 20.

[0042] The electrode assembly 20 includes a main body 24 and a flattened portion 25 connected to each other. The main body 24 and the flattened portion 25 are arranged along the axial direction X. The flattened portion 25 is located at the portion where the first portion 211 exceeds the second portion 212 , and, along the axial direction X, the flattened portion 25 exceeds the main body 24 .

[0043] The electrode assembly 20 and the current collecting plate 30 are arranged in an axial direction X, and the current collecting plate 30 is connected to the flattened portion 25. The diameter of the main body 24 is defined as D1, and the diameter of the flattened portion 25 is defined as D2, where D2 is less than D1.

[0044] In the above-mentioned cylindrical battery 100, the first part 211 of the first pole piece 21 exceeds the second part 212 along the axial direction X, and the part of the first part 211 exceeding the second part 212 forms the flattened part 25 of the electrode assembly 20, and the diameter D2 of the flattened part 25 is smaller than the diameter D1 of the main body 24. Compared with the electrode assembly in which the main body and the flattened part have equal diameters, the end of the electrode assembly 20 in the axial direction X is smaller, which is convenient for compressing the flattened part 25 and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly 20 and improving the energy density of the cylindrical battery 100. At the same time, the first part 211 is located at the starting section of the winding of the electrode assembly 20, so that the flattened part 25 is denser after compression, which is convenient for connecting the current collecting plate 30 and improving the current flow capacity between the first pole piece 21 and the current collecting plate 30, thereby reducing the temperature rise.

[0045] The axial direction X refers to the direction along the central axis of the cylindrical battery 100 and toward the top of the cylindrical battery 100 .

[0046] In one embodiment, the housing 10 includes a side wall 11 and a bottom wall 12 . The bottom wall 12 and the side wall 11 are arranged along the axial direction X and connected to each other to form a cylindrical cavity. The electrode assembly 20 and the current collecting plate 30 are located in the cavity.

[0047] As shown in Figures 2, 4 and 6, in one embodiment, one of the first electrode 21 and the second electrode 22 is a positive electrode and the other is a negative electrode. Optionally, the first electrode 21 is a positive electrode and the second electrode 22 is a negative electrode.

[0048] In one embodiment, along the axial direction X, part of the diaphragm 23 extends beyond the second pole piece 22 , and part of the first portion 211 extends beyond the diaphragm 23 . In one implementation, the flattened portion 25 is the part of the first portion 211 extending beyond the diaphragm 23 along the axial direction X.

[0049] In one embodiment, along a direction opposite to the axial direction X, a portion of the diaphragm 23 extends beyond the first electrode piece 21, and a portion of the second electrode piece 22 extends beyond the diaphragm 23 and connects to the bottom wall 12. In one embodiment, the second electrode piece 22 is electrically connected to the housing 10, and the housing 10 serves as an output terminal of the cylindrical battery 100.

[0050] In one embodiment, the cylindrical battery 100 further includes a structural member 70, which is disposed within the housing 10. Along the axial direction X, the bottom wall 12, the structural member 70, and the electrode assembly 20 are arranged. The structural member 70 connects the bottom wall 12 and the second electrode sheet 22, so that the second electrode sheet 22 is electrically connected to the housing 10.

[0051] As shown in Figures 2, 4, and 7, in one embodiment, the cylindrical battery 100 further includes an end cap 40. The current collecting disc 30 and the end cap 40 are arranged along the axial direction X. The current collecting disc 30 is connected to the end cap 40. The first electrode sheet 21 is electrically connected to the end cap 40. The end cap 40 serves as an output terminal of the cylindrical battery 100. In one embodiment, the end cap 40 can serve as the positive terminal of the cylindrical battery 100, and the housing 10 can serve as the negative terminal of the cylindrical battery 100.

[0052] In one embodiment, the cylindrical battery 100 further includes an orifice plate 60 and an explosion-proof disc 50. The current collecting plate 30, the orifice plate 60, the explosion-proof disc 50, and the end cap 40 are arranged along the axial direction X. The current collecting plate 30 is connected to the orifice plate 60, and the explosion-proof disc 50 is connected to the orifice plate 60 and the end cap 40, so that the first electrode 21 is electrically connected to the end cap 40.

[0053] In one embodiment, the cylindrical battery 100 further includes a second insulating member 82, which connects the sidewall 11 and the explosion-proof disk 50. The second insulating member 82 provides insulation and reduces the risk of short circuiting in the cylindrical battery 100. In one embodiment, the second insulating member 82 connects the sidewall 11 and the orifice plate 60, which further reduces the risk of short circuiting in the cylindrical battery 100.

[0054] In one embodiment, the second insulating member 82 is made of plastic material, which is beneficial to ensuring its insulation effect and reducing its own weight, thereby reducing the impact of its weight on the cylindrical battery 100.

[0055] In one embodiment, the second insulating member 82 is formed by melting plastic and then solidifying it through injection molding equipment, which helps to simplify the manufacturing process of the second insulating member 82, improve the manufacturing efficiency of the second insulating member 82, and reduce costs.

[0056] In one embodiment, the material of the second insulating member 82 includes but is not limited to any one of silicone, rubber, polypropylene (PP), and polyethylene terephthalate (PET).

[0057] In one embodiment, the explosion-proof disk 50 is provided with a groove 51, which is recessed in a direction opposite to the axial direction X. The groove 51 constitutes a weak area of ​​the explosion-proof disk 50. The orifice plate 60 is provided with a through hole 61, which allows electrolyte or gas to pass through.

[0058] In one embodiment, when the gas pressure in the cylindrical battery 100 increases, the gas can act on the explosion-proof plate 50 through the through hole 61. When the gas pressure increases to the pressure resistance threshold of the weak area of ​​the explosion-proof plate 50, the gas in the shell 10 can break through the explosion-proof plate 50 to achieve the purpose of pressure relief, reduce the risk of explosion of the cylindrical battery 100, and improve the safety performance of the cylindrical battery 100.

[0059] As shown in Figures 2 to 5 and 8 to 10, in one embodiment, the current collecting plate 30 includes a base portion 31 and an extension portion 32 connected to each other. The base portion 31 and the extension portion 32 are stacked along the axial direction X. The base portion 31 is connected to the flattened portion 25, and the extension portion 32 is connected to the orifice plate 60. The current collecting plate 30 is designed as a two-layer structure, which helps to reduce the height space it occupies and improve the energy density of the cylindrical battery 100.

[0060] In one embodiment, the original state of the current collecting tray 30 is an unfolded state (as shown in FIG8 ). During the assembly process of the cylindrical battery 100 , the current collecting tray 30 is bent along the bending line 33 to form a two-layer structure (as shown in FIG10 ), with the base portion 31 and the extension portion 32 stacked.

[0061] In one embodiment, along the radial direction of the cylindrical battery 100, the maximum length of the current collecting plate 30 in the unfolded state is defined as L2, and 1.5≤L2 / D1≤2. This is beneficial to reducing the number of layers of the current collecting plate 30 after folding, reducing the height space occupied by it, and improving the energy density of the cylindrical battery 100.

[0062] In one embodiment, the flattened portion 25 and the current collecting disk 30 are welded together, which is beneficial to improving the connection stability between the first pole piece 21 and the current collecting disk 30, improving the flow capacity between the first pole piece 21 and the current collecting disk 30, and reducing temperature rise.

[0063] In one embodiment, the current collecting plate 30 and the side wall 11 are separated along the radial direction of the cylindrical battery 100 , which helps to reduce the risk of short circuit of the cylindrical battery 100 and improve its safety performance.

[0064] In one embodiment, during the assembly process of the cylindrical battery 100, the substrate portion 31 is welded to the flattened portion 25, and then the current collecting plate 30 is bent along the bending line 33 so that the substrate portion 31 and the extension portion 32 are stacked. The current collecting plate 30 and the electrode assembly 20 are installed in the shell 10, and the current collecting plate 30 is pressed in the direction opposite to the axial direction X to compress the space occupied by the flattened portion 25, and then the orifice plate 60 and the explosion-proof plate 50 and other structures are connected.

[0065] As shown in Figures 2 to 6, in one embodiment, D1-D2 ≥ 3 mm, which is beneficial to compressing the flattened portion 25, reducing the length of the electrode assembly 20 along the axial direction X, and improving the energy density of the cylindrical battery 100. It is also beneficial to ensure the connection area between the flattened portion 25 and the current collecting plate 30, improve the flow capacity between the electrode assembly 20 and the current collecting plate 30, and reduce the temperature rise.

[0066] In one embodiment, 13 mm ≤ D2 ≤ 40 mm, which is beneficial for further ensuring the connection area between the flattened portion 25 and the current collecting plate 30 and further improving the current flow capacity between the electrode assembly 20 and the current collecting plate 30 .

[0067] In one embodiment, the diameter D2 of the flattened portion 25 is any one of 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm and 40mm, which is beneficial to ensure the connection area between the flattened portion 25 and the current collecting plate 30 and improve the flow capacity between the electrode assembly 20 and the current collecting plate 30.

[0068] In one embodiment, the first electrode 21 includes a first current collector 214, a first insulating layer 215 and a first active layer 216. The first insulating layer 215 and the first active layer 216 are both arranged on the same surface of the first current collector 214, and the first active layer 216 and the first insulating layer 215 are arranged along the axial direction X.

[0069] In one embodiment, the first active layer 216 is disposed on both side surfaces of the first current collector 214 . In one embodiment, the first insulating layer 215 is disposed on both side surfaces of the first current collector 214 .

[0070] In one embodiment, the first current collector 214 further includes a hollow foil region 217 , where the first insulating layer 215 and the first active layer 216 are not provided. The first active layer 216 , the first insulating layer 215 , and the hollow foil region 217 are arranged along the axial direction X. In one embodiment, the ends of the hollow foil region 217 along the axial direction X are flattened to form a flattened portion 25 .

[0071] In one embodiment, along the axial direction X, the first insulating layer 215 and the flattened portion 25 are separated, and the distance between the end surface 251 of the flattened portion 25 and the first insulating layer 215 is defined as L1, 0.5mm≤L1≤1mm, which is beneficial to reducing the length of the electrode assembly 20 along the axial direction X and improving the energy density of the cylindrical battery 100.

[0072] In one embodiment, L is any one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm, which is beneficial to reducing the length of the electrode assembly 20 along the axial direction X and improving the energy density of the cylindrical battery 100.

[0073] In one embodiment, along the axial direction X, the first insulating layer 215 is closer to the current collecting plate 30 than the first active layer 216 . Part of the first insulating layer 215 is located in the first portion 211 , and part of the first insulating layer 215 is located in the second portion 212 .

[0074] In one embodiment, during the preparation process of the first electrode 21, the first part 211 and the second part 212 are formed by cutting, so that the end of the second part 212 along the axial direction X has a first insulating layer 215. The first insulating layer 215 can cover and protect the burrs generated by cutting at the end of the second part 212, thereby reducing the risk of the burrs puncturing the diaphragm 23 and improving the safety performance of the cylindrical battery 100.

[0075] In one embodiment, part of the first insulating layer 215 is located on the main body portion 24 , and part of the first insulating layer 215 is located on the flattened portion 25 .

[0076] In one embodiment, along the axial direction X, the width of the first insulating layer 215 in the first portion 211 is defined as W1 , and the width of the first insulating layer 215 in the second portion 212 is defined as W2 , where W1 > W2 .

[0077] In one embodiment, along the direction opposite to the axial direction X, the end of the first portion 211 away from the collecting plate 30 is the first end, the end of the second portion 212 away from the collecting plate 30 is the second end, and the first end does not exceed the second end.

[0078] In one embodiment, the first end and the second end are flush.

[0079] In one embodiment, the second pole piece 22 includes a second current collector 221 and a second active layer (not shown), and the second active layer is disposed on the surface of the second current collector 221. In one embodiment, in a direction opposite to the axial direction X, the second active layer is not disposed at the end of the second current collector 221. The end of the second current collector 221 is connected to the structural member 70, thereby electrically connecting the second pole piece 22 and the structural member 70.

[0080] In one embodiment, the end of the second current collector 221 is welded to the structural member 70, which is beneficial to improving the connection stability between the second pole piece 22 and the structural member 70, improving the seismic performance of the cylindrical battery 100, and also beneficial to improving the flow capacity between the second pole piece 22 and the structural member 70 and reducing the temperature rise.

[0081] In one embodiment, the structural member 70 and the bottom wall 12 are welded together, which is beneficial to improving the connection stability between the bottom wall 12 and the structural member 70, improving the seismic performance of the cylindrical battery 100, and also beneficial to improving the flow capacity between the bottom wall 12 and the structural member 70 and reducing temperature rise.

[0082] In one embodiment, the second active layer is disposed on both side surfaces of the second current collector 221 .

[0083] In one embodiment, the cylindrical battery 100 further includes a first insulating member 81 . The first insulating member 81 is disposed within the housing 10 , and the main body 24 and the first insulating member 81 are arranged along the axial direction X. The first insulating member 81 can serve as a filler and protective element, thereby reducing the risk of the electrode assembly 20 shaking along the axial direction X and improving the safety performance of the cylindrical battery 100 .

[0084] In one embodiment, when viewed in the direction opposite to the axial direction X, the first insulating member 81 surrounds the flattened portion 25. Along the radial direction of the cylindrical battery 100, the projection of the first insulating member 81 overlaps with the projection of the flattened portion 25. The first insulating member 81 provides insulation and protection for the flattened portion 25, reducing the risk of short circuits in the electrode assembly 20.

[0085] In one embodiment, along the axial direction X, the thickness of the first insulating member 81 is defined as H, 0.2 mm ≤ H ≤ 1 mm, which is conducive to the first insulating member 81 playing the role of insulation and filling protection, improving the safety performance of the cylindrical battery 100, and at the same time, it will not occupy too much space, reducing the impact on the energy density of the cylindrical battery 100.

[0086] In one embodiment, the thickness H of the first insulating member 81 is any one of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1 mm, which is beneficial for the first insulating member 81 to play the role of insulation and filling protection, improve the safety performance of the cylindrical battery 100, reduce the space it occupies, and reduce the impact on the energy density of the cylindrical battery 100.

[0087] In one embodiment, the first insulating member 81 is made of plastic, which is beneficial for ensuring its insulation and buffering effects, and can also reduce its own weight and reduce the impact of its weight on the cylindrical battery 100.

[0088] In one embodiment, the first insulating member 81 is formed by melting plastic and then solidifying it through injection molding equipment, which is beneficial to simplifying the manufacturing process of the first insulating member 81, improving the manufacturing efficiency of the first insulating member 81, and reducing costs.

[0089] In one embodiment, the material of the first insulating member 81 includes but is not limited to any one of silicone, rubber, polypropylene (PP) and polyethylene terephthalate (PET).

[0090] To sum up, in the cylindrical battery 100 of the present application, the first part 211 of the first pole piece 21 exceeds the second part 212 along the axial direction X, and the part of the first part 211 exceeding the second part 212 forms the flattened part 25 of the electrode assembly 20, and the diameter D2 of the flattened part 25 is smaller than the diameter D1 of the main body 24. Compared with the electrode assembly 20 in which the main body 24 and the flattened part 25 have equal diameters, the end of the electrode assembly 20 of the present application along the axial direction X is smaller, which is convenient for compressing the flattened part 25 and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly 20 and improving the energy density of the cylindrical battery 100. At the same time, the first part 211 is located at the starting section of the winding of the electrode assembly 20, so that the flattened part 25 is denser after compression, which is convenient for connecting the current collecting plate 30 and improving the current flow capacity between the first pole piece 21 and the current collecting plate 30, thereby reducing the temperature rise.

[0091] As shown in FIG11 , an embodiment of the present application further provides an electric device 200 , comprising the cylindrical battery 100 according to any one of the aforementioned embodiments.

[0092] In the above-mentioned electrical equipment 200, the first part 211 of the first electrode 21 in the cylindrical battery 100 exceeds the second part 212 along the axial direction X, and the part of the first part 211 exceeding the second part 212 forms the flattened part 25 of the electrode assembly 20, and the diameter D2 of the flattened part 25 is smaller than the diameter D1 of the main body 24. Compared with the electrode assembly 20 in which the main body 24 and the flattened part 25 have equal diameters, the end of the electrode assembly 20 in the axial direction X is smaller, which is convenient for compressing the flattened part 25, and can also reduce the space occupied by the flattened area, thereby reducing the length of the electrode assembly 20, improving the energy density of the cylindrical battery 100, and reducing the impact of the energy density of the cylindrical battery 100 on the electrical equipment 200.

[0093] In one embodiment, the electric device 200 includes but is not limited to any one of an electric vehicle, an electric two-wheeled vehicle, a drone, a home appliance, and a consumer electronic product.

[0094] In addition, those skilled in the art may also make other changes within the spirit of this application. Of course, these changes made according to the spirit of this application should be included in the scope disclosed in this application.

Claims

1. A cylindrical battery, characterized in that: It includes a shell, an electrode assembly and a current collecting plate arranged in the shell; The electrode assembly is formed by stacking a first electrode sheet, a diaphragm and a second electrode sheet and then winding them. The diaphragm is arranged between the first electrode sheet and the second electrode sheet. Along the winding direction of the electrode assembly, the first electrode sheet includes a first part and a second part connected to each other. The first part includes a winding start section of the first electrode sheet. Along the axial direction of the cylindrical battery, the end surface of the first part exceeds the end surface of the second part. The electrode assembly comprises a main body and a flattened portion connected to each other, wherein the main body and the flattened portion are arranged along the axial direction, the flattened portion is a portion where the first portion exceeds the second portion, and along the axial direction, the flattened portion exceeds the main body; The electrode assembly and the current collecting plate are arranged along the axial direction, and the current collecting plate is connected to the flattened portion; The diameter of the main body is defined as D1, the diameter of the flattened portion is defined as D2, and D2<D1.

2. The cylindrical battery according to claim 1, characterized in that: D1-D2≥3mm.

3. The cylindrical battery according to claim 1, characterized in that: 13mm≤D2≤40mm.

4. The cylindrical battery according to claim 1, characterized in that: The cylindrical battery further includes a first insulating member, which is disposed in the housing, and the main body and the first insulating member are arranged along the axial direction; When viewed in the opposite direction of the axial direction, the first insulating member surrounds the flattened portion; Along the radial direction of the cylindrical battery, a projection of the first insulating member and a projection of the flattened portion overlap.

5. The cylindrical battery according to claim 4, characterized in that: Along the axial direction, the thickness of the first insulating member is defined as H, 0.2 mm ≤ H ≤ 1 mm.

6. The cylindrical battery according to claim 1, characterized in that: The first pole piece includes a first current collector, a first insulating layer and a first active layer, and the first insulating layer and the first active layer are both arranged on the same surface of the first current collector; The first current collector includes a hollow foil region, the hollow foil region is not provided with the first insulating layer and the first active layer, and the first active layer, the first insulating layer and the hollow foil region are arranged along the axial direction; Part of the empty foil area is flattened to form the flattened portion; Along the axial direction, a distance between an end surface of the flattened portion and the first insulating layer is defined as L1, and 0.5 mm ≤ L1 ≤ 1 mm.

7. The cylindrical battery according to claim 1, characterized in that: The first pole piece includes a first current collector, a first insulating layer and a first active layer, the first insulating layer and the first active layer are both arranged on the same surface of the first current collector, the first active layer and the first insulating layer are arranged along the axial direction, and the first insulating layer is closer to the current collector than the first active layer; A portion of the first insulating layer is located in the first portion, and a portion of the first insulating layer is located in the second portion.

8. The cylindrical battery according to claim 7, characterized in that: Along the axial direction, the width of the first insulating layer in the first portion is defined as W1, and the width of the first insulating layer in the second portion is defined as W2, where W1>W2.

9. The cylindrical battery according to claim 1, characterized in that: The current collecting plate includes a base portion and an extension portion connected to each other, the base portion and the extension portion are stacked along the axial direction, the base portion is connected to the flattened portion, and the extension portion is connected to the pole or cover of the cylindrical battery.

10. The cylindrical battery according to claim 9, characterized in that: Along the radial direction of the cylindrical battery, the maximum length of the current collecting plate after unfolding is defined as L2, and 1.5≤L2 / D1≤2.

11. An electrical device, characterized in that: Comprising a cylindrical battery as claimed in any one of claims 1 to 10.

Images