Cylindrical battery, battery pack and electronic device

Abstract

The utility model provides a cylindrical battery, a battery pack and an electronic device. The cylindrical battery includes: a case; the electrode assembly is accommodated in the shell and comprises a winding structure formed by laminating and winding a positive plate, a diaphragm and a negative plate; a negative current collector of the negative plate comprises a negative active material coating region and a negative active material non-coating region; the negative electrode non-coated active material region comprises a negative electrode vertical part arranged along the height direction, a negative electrode flat part arranged along the radial direction, and a negative electrode bending part connected between the negative electrode vertical part and the negative electrode flat part; at least part of the negative electrode vertical part is covered with a reinforcing layer, the distance between the second edge, away from the negative electrode active material coating area, of the reinforcing layer and the diaphragm is d1 in the preset direction, and the value range of d1 is 0.2 mm-3 mm. The reinforcing layer covers a part of the area of the negative pole vertical part, so that the supporting performance of the bending of the negative pole lug can be improved, the diaphragm is prevented from being scalded, and the safety of the battery cell is improved.

Description

Technical Field

[0001] This utility model relates to the field of batteries, and in particular to a cylindrical battery, a battery pack, and an electronic device. Background Technology

[0002] In recent years, with the rapid development of electric vehicles, consumer electronics, and new energy storage systems, battery technology has become an important factor in the development of electric vehicles.

[0003] In the development of battery technology, how to improve the safety of battery cells is a technical problem that urgently needs to be solved. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the above-mentioned technical problems of the prior art and provide a cylindrical battery, battery pack and electronic device.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] A cylindrical battery, characterized in that it comprises:

[0007] case;

[0008] An electrode assembly is housed within the housing. The electrode assembly includes a positive electrode sheet, a separator, and a negative electrode sheet stacked and wound together to form a wound structure. The positive electrode sheet includes a positive current collector, and the negative electrode sheet includes a negative current collector. Along the height direction of the wound structure, the negative current collector includes a negative electrode coated active material region covered by a negative electrode active material layer and a negative electrode uncoated active material region not covered by the negative electrode active material layer.

[0009] The uncoated active material region of the negative electrode includes a vertical negative electrode portion disposed along the height direction, a flat negative electrode portion disposed radially along the winding structure, and a negative electrode bend portion connecting the vertical negative electrode portion and the flat negative electrode portion;

[0010] At least a portion of the negative electrode upright portion is covered with a reinforcing layer. The reinforcing layer includes a first edge close to the area of ​​the negative electrode coated with active material and a second edge away from the area of ​​the negative electrode coated with active material. Along a predetermined direction from the area of ​​the negative electrode coated with active material to the area of ​​the negative electrode uncoated with active material, the second edge extends beyond the membrane by a distance d1, where the value of d1 ranges from 0.2 mm to 3 mm.

[0011] In this technical solution, by covering at least a portion of the negative electrode upright portion with a reinforcing layer, the support for bending of the negative electrode tab can be improved. Specifically, since the negative electrode tab begins to bend at the negative electrode bending point, covering a portion of the negative electrode upright portion with a reinforcing layer can increase the position of the bend in the height direction, thereby increasing the relative position of the welding area of ​​the negative electrode tab and the separator in the height direction. This achieves the purpose of avoiding scalding the separator during welding and improves the safety of the battery cell. Furthermore, by setting the second edge of the reinforcing layer to extend beyond the range of the separator distance d1 along a preset direction, on the one hand, it avoids the distance d1 being too small, in which case the reinforcing layer will not provide support; on the other hand, it avoids the distance d1 being too large, which would make the size of the winding structure too large in the height direction, thus affecting the energy density of the battery.

[0012] Preferably, along the preset direction, the distance by which the diaphragm extends beyond the region of the negative electrode coated with active material is d2, and the value of d1 / d2 ranges from 0.2 to 0.8.

[0013] Preferably, the grayscale value of the reinforcing layer is 0-192.

[0014] Preferably, along the radial direction of the winding structure, the negative electrode upright includes a first negative electrode side facing away from the central hole of the winding structure and a second negative electrode side facing the central hole, wherein at least a portion of the first negative electrode side and / or the second negative electrode side is covered by the reinforcing layer.

[0015] Preferably, the thickness of the negative electrode current collector is less than or equal to 5.5 μm and greater than or equal to 4 μm.

[0016] Preferably, at least a portion of the uncoated active material area of ​​the negative electrode forms a negative electrode tab, and along the winding direction of the winding structure, two adjacent negative electrode tabs have a predetermined spacing.

[0017] The negative electrode tab is in the shape of a trapezoid, with the lower base of the trapezoid located near the area of ​​the negative electrode coated with active material, and the end of the negative electrode tab near the area of ​​the negative electrode coated with active material is covered with the reinforcing layer.

[0018] Preferably, the housing includes surrounding sidewalls, one end of which is formed with an opening;

[0019] The cylindrical battery also includes:

[0020] Cover plate, installed in the opening;

[0021] A negative electrode current collector is disposed between the electrode assembly and the cover plate and is electrically connected to the housing. One side of the connecting piece of the negative electrode current collector is welded to the flat part of the negative electrode.

[0022] Preferably, the housing further includes a crimping portion formed at one end of the sidewall near the opening and recessed into the housing.

[0023] The other side of the connecting piece of the negative electrode current collector is welded to the crimping part;

[0024] or,

[0025] The outer periphery of the cover plate, the end of the side wall of the housing near the opening, and the outer periphery of the connecting piece of the negative electrode current collector are connected by welding.

[0026] A battery pack characterized in that it includes cylindrical batteries as described above.

[0027] An electronic device characterized in that it includes a battery pack as described above.

[0028] The positive and progressive effects of this utility model are as follows:

[0029] This invention improves the support of the negative electrode tab during bending by covering a portion of the upright negative electrode section with a reinforcing layer. Specifically, since the negative electrode tab begins to bend at the negative electrode bending point, covering a portion of the upright negative electrode section with a reinforcing layer increases the bending position in the height direction. This increases the relative height of the welding area of ​​the negative electrode tab and the separator, preventing damage to the separator during welding and improving the safety of the battery cell. Furthermore, by setting the second edge of the reinforcing layer to extend beyond the range of the separator distance d1 along a preset direction, it avoids both situations where the distance d1 is too small, rendering the reinforcing layer ineffective, and where the distance d1 is too large, causing the winding structure to be too large in the height direction, thus affecting the energy density of the battery. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the cylindrical battery of Embodiment 1 of this utility model.

[0031] Figure 2 for Figure 1 A magnified schematic diagram of part A in the middle.

[0032] Figure 3 This is a three-dimensional structural diagram of the electrode assembly of the cylindrical battery according to Embodiment 1 of this utility model.

[0033] Figure 4 This is a partial cross-sectional view of the electrode assembly of the cylindrical battery according to Embodiment 1 of this utility model.

[0034] Figure 5 for Figure 4 A magnified schematic diagram of part B in the middle section.

[0035] Figure 6 This is a partial cross-sectional view of the single-turn negative electrode sheet of the cylindrical battery according to Embodiment 1 of this utility model.

[0036] Figure 7 This is a schematic diagram of the structure of the negative electrode sheet of the cylindrical battery in Embodiment 1 of this utility model when it is not wound.

[0037] Figure 8 This is a partial cross-sectional view of the single-turn positive electrode sheet of the cylindrical battery according to Embodiment 1 of this utility model.

[0038] Figure 9 This is a schematic diagram of the battery pack structure of Embodiment 1 of this utility model.

[0039] Figure 10 This is a schematic diagram of the electronic device according to Embodiment 1 of this utility model.

[0040] Figure 11 This is a cross-sectional view of the cylindrical battery of Embodiment 2 of this utility model.

[0041] Figure 12 for Figure 11 A magnified schematic diagram of part C in the middle.

[0042] Explanation of reference numerals in the attached figures

[0043] Electronic devices 1000

[0044] Battery pack 100

[0045] Box 110

[0046] Box lid 120

[0047] Work Department 300

[0048] Cylindrical battery 1

[0049] Casing 10

[0050] end wall 11

[0051] Side wall 12

[0052] Receiving cavity 13

[0053] Opening 14

[0054] Electrode assembly 20

[0055] 201 winding structure

[0056] Center Hole 2011

[0057] Positive electrode 21

[0058] Positive current collector 211

[0059] Positive electrode active material layer 2111

[0060] Positive electrode coating active material region 212

[0061] Uncoated active material region 213 of the positive electrode

[0062] Positive pole vertical part 214

[0063] Positive flat part 215

[0064] Positive electrode bending section 216

[0065] Positive electrode 217

[0066] Diaphragm 22

[0067] Negative electrode 23

[0068] Negative current collector 231

[0069] Negative electrode active material layer 2311

[0070] Negative electrode coating active material region 232

[0071] Uncoated active material region 233 on the negative electrode

[0072] Negative electrode vertical part 234

[0073] First negative electrode side 2341

[0074] Second negative electrode side 2342

[0075] Negative electrode flat part 235

[0076] Negative electrode bending section 236

[0077] Negative electrode tab 237

[0078] Reinforcement layer 24

[0079] First Edge 241

[0080] Second edge 242

[0081] crimping part 30

[0082] Cover plate 40

[0083] Insulating seal 50

[0084] Positive current collector 61

[0085] Negative current collector 62

[0086] Connecting piece 621

[0087] 70 pole

[0088] Insulating component 80

[0089] Height direction H

[0090] Winding direction P

[0091] Radial R

[0092] Preset direction Q Detailed Implementation

[0093] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0094] Example 1

[0095] like Figure 1 and Figure 2 As shown, this embodiment provides a cylindrical battery 1. The cylindrical battery 1 includes a housing 10 and an electrode assembly 20, the electrode assembly 20 being housed within the housing 10.

[0096] like Figures 3 to 8 As shown, the electrode assembly 20 includes a spiral structure 201 formed by stacking and winding a positive electrode 21, a separator 22, and a negative electrode 23; the positive electrode 21 includes a positive current collector 211, and the negative electrode 23 includes a negative current collector 231; along the height direction H of the spiral structure 201, the negative current collector 231 includes a negative electrode coated active material region 232 covered by the negative electrode active material layer 2311 and a negative electrode uncoated active material region 233 not covered by the negative electrode active material layer 2311.

[0097] The negative electrode uncoated active material region 233 includes a negative electrode upright portion 234 disposed along the height direction H, a negative electrode flat portion 235 disposed along the radial direction R of the winding structure 201, and a negative electrode bent portion 236 connecting the negative electrode upright portion 234 and the negative electrode flat portion 235.

[0098] At least a portion of the negative electrode upright portion 234 is covered with a reinforcing layer 24. The reinforcing layer 24 includes a first edge 241 close to the negative electrode coated active material region 232 and a second edge 242 away from the negative electrode coated active material region 232. Along a predetermined direction Q from the negative electrode coated active material region 232 to the negative electrode uncoated active material region 233, the second edge 242 extends beyond the separator 22 by a distance d1, where the value of d1 ranges from 0.2 mm to 3 mm.

[0099] In this way, by covering at least a portion of the negative electrode upright portion 234 with the reinforcing layer 24, the support of the negative electrode tab 237 during bending can be improved. Specifically, since the negative electrode tab 237 begins to bend at the negative electrode bending portion 236, by covering a portion of the negative electrode upright portion 234 with the reinforcing layer 24, the bending position in the height direction H can be increased, thereby increasing the relative position of the welding area of ​​the negative electrode tab 237 and the separator 22 in the height direction H. This achieves the purpose of avoiding burns to the separator 22 during welding and improves the safety of the battery cell. Furthermore, by setting the second edge 242 of the reinforcing layer 24 to extend beyond the range of the distance d1 of the separator 22 along the preset direction Q, on the one hand, it avoids the distance d1 being too small, in which case the reinforcing layer 24 will not provide support; on the other hand, it avoids the distance d1 being too large, which would make the size of the winding structure 201 in the height direction H too large, thus affecting the energy density of the battery. The value of d1 ranges from 0.2mm to 3mm, for example, it can be 0.2mm, 1mm, 1.6mm, 2.4mm or 3mm, etc.

[0100] It should be noted that the negative electrode flat portion 235 is arranged along the radial direction R of the winding structure 201, meaning that the negative electrode flat portion 235 is arranged along the radial direction R of the winding structure 201 and in a direction close to the radial direction R of the winding structure 201. At least a portion of the negative electrode upright portion 234 is covered with the reinforcing layer 24. This can be either a portion of the negative electrode upright portion 234 is covered with the reinforcing layer 24, or the entire area of ​​the negative electrode upright portion 234 is covered with the reinforcing layer 24.

[0101] Furthermore, along the preset direction Q, the distance by which the separator 22 extends beyond the negative electrode coated active material region 232 is d2, and the value of d1 / d2 ranges from 0.2 to 0.8. Thus, by setting the range of d1 / d2, the position of the reinforcing layer 24 in the height direction H can be controlled within a reasonable range. On the one hand, this avoids d1 / d2 being too small, rendering the reinforcing layer 24 ineffective; on the other hand, it avoids d1 / d2 being too large, causing the winding structure 201 to be too large along the height direction H, thereby affecting the energy density of the battery.

[0102] Preferably, the grayscale value of the reinforcing layer 24 is 0-192. A grayscale value of 0-192, meaning that the color of the reinforcing layer 24 is preferably gray or black, allows it to absorb the laser during laser cutting, avoiding laser reflection (e.g., when white). This reduces laser reflection and scattering, concentrating the laser energy and making the current collector easier to cut. Furthermore, this allows for cutting at relatively low power, reducing the likelihood of burrs on the cut edge and minimizing short circuits within the battery cell caused by burrs.

[0103] When the grayscale value is closer to 0, the color of the reinforcing layer 24 is darker. Compared with the white reinforcing layer in the prior art, the reinforcing layer 24 in this embodiment has a much stronger absorption effect on laser. When the grayscale value is greater than 192, the color of the reinforcing layer 24 becomes whiter as the grayscale value increases, and the absorption effect of the reinforcing layer 24 on laser is weaker.

[0104] An image of the reinforcement layer 24 can be captured by a camera or sensor, and then the grayscale value of the image can be analyzed by computer software to obtain the actual grayscale value of the reinforcement layer 24.

[0105] Preferably, along the radial direction R of the winding structure 201, the negative electrode upright portion 234 includes a first negative electrode side 2341 facing away from the central hole 2011 of the winding structure 201 and a second negative electrode side 2342 facing the central hole 2011, wherein at least a portion of the first negative electrode side 2341 and / or the second negative electrode side 2342 is covered with a reinforcing layer 24. Thus, by covering at least a portion of the first negative electrode side 2341 and / or the second negative electrode side 2342 with the reinforcing layer 24, the position of the bend in the height direction H can be increased, thereby increasing the relative position of the welding area of ​​the negative electrode tab 237 and the separator 22 in the height direction H, achieving the purpose of avoiding burns to the separator 22 during welding and improving the safety of the battery cell.

[0106] Please refer to the following: Figure 5 In this embodiment, both the first negative electrode side 2341 and the second negative electrode side 2342 are at least partially covered by the reinforcing layer 24. However, this is not a limitation. In other embodiments, only at least a portion of the first negative electrode side 2341 or only at least a portion of the second negative electrode side 2342 may be covered by the reinforcing layer 24. Adjustments can be made according to design requirements.

[0107] Preferably, the thickness t of the negative electrode current collector 231 is less than or equal to 5.5 μm and greater than or equal to 4 μm, for example, it can be 4 μm, 4.3 μm, 4.75 μm, 5.0 μm, or 5.5 μm. When the thickness t of the negative electrode current collector 231 is less than or equal to 5.5 μm and greater than or equal to 4 μm, the negative electrode current collector 231 is an ultra-thin current collector. Ultra-thin current collectors are prone to wrinkling. In this embodiment, by covering a portion of the negative electrode upright portion 234 with a reinforcing layer 24, the support of the negative electrode tab 237 during bending can be improved, solving the problem of wrinkling of ultra-thin current collectors. At the same time, ultra-thin current collectors can improve the volumetric energy density of the battery. Furthermore, by covering a portion of the negative electrode upright portion 234 with a reinforcing layer 24, the bending position in the height direction H can be improved, thereby increasing the relative position of the welding area of ​​the negative electrode tab 237 and the separator 22 in the height direction H, achieving the purpose of avoiding burns to the separator 22 during welding and improving the safety of the battery cell.

[0108] Specifically, at least a portion of the uncoated active material area 233 of the negative electrode forms a negative electrode tab 237. Along the winding direction P of the winding structure 201, adjacent negative electrode tabs 237 have a predetermined spacing. The negative electrode tab 237 is trapezoidal in shape, with the lower base of the trapezoid close to the coated active material area 232, and a reinforcing layer 24 covering the end of the negative electrode tab 237 near the coated active material area 232. Thus, by setting a predetermined spacing between adjacent negative electrode tabs 237 along the winding direction P, the bending of the negative electrode tab 237 can be better achieved. By setting the shape of the negative electrode tab 237 as a trapezoid, with the lower base of the trapezoid close to the coated active material area 232, the number of stacked negative electrode tabs 237 formed in the radial direction R after bending is relatively uniform. Because the upper base of the trapezoidal negative electrode tab 23 is shorter than the lower base, the end of the negative electrode tab 23 near the upper base is narrower. Therefore, a certain amount of pressure is required to hold the negative electrode tab 23 in place when it is welded to the current collector. Furthermore, covering the end of the negative electrode tab 237 near the negative electrode active material coating area 232 with a reinforcing layer 24 effectively increases the strength of the negative electrode tab 23, preventing it from affecting the height of the electrode assembly 20. Additionally, it prevents the welding surface (welding area) between the negative electrode tab 23 and the current collector from being too close to the diaphragm 22, thus avoiding burns to the diaphragm 22.

[0109] It should be noted that the negative electrode tab 237 is trapezoidal in shape, meaning that when the negative electrode sheet 23 is in an unwound state, the lower base of the trapezoid is longer than the upper base. Please refer to [reference needed]. Figure 7 Along a direction opposite to the preset direction Q, the negative electrode tab 237 includes a negative electrode flat portion 235, a negative electrode bent portion 236, and at least a portion of the negative electrode upright portion 234 connected in sequence.

[0110] Along the height direction H of the winding structure 201, the positive electrode current collector 211 includes a positive electrode coated active material region 212 covered by the positive electrode active material layer 2111 and a positive electrode uncoated active material region 213 not covered by the positive electrode active material layer 2111. The positive electrode uncoated active material region 213 includes a positive electrode upright portion 214 disposed along the height direction H, a positive electrode flat portion 215 disposed along the radial direction R of the winding structure 201, and a positive electrode bend portion 216 connecting the positive electrode upright portion 214 and the positive electrode flat portion 215. At least a portion of the positive electrode uncoated active material region 213 forms a positive electrode tab 217.

[0111] It should be noted that the positive electrode bending portion 216 is arc-shaped. The positive electrode bending portion 216 includes a first positive electrode bending end point A1 and a second positive electrode bending end point A2. The first positive electrode bending end point A1 is the position where the tangent of the positive electrode bending portion 216 intersects with the extension direction of the positive electrode upright portion 214, and the second positive electrode bending end point A2 is the position where the tangent of the positive electrode bending portion 216 intersects with the extension direction of the positive electrode flat portion 215.

[0112] Similarly, the negative electrode bending portion 236 is arc-shaped, and the negative electrode bending portion 236 includes a first negative electrode bending end point B1 and a second negative electrode bending end point B2. The first negative electrode bending end point B1 is the position where the tangent of the negative electrode bending portion 236 intersects with the extension direction of the negative electrode upright portion 234, and the second negative electrode bending end point B2 is the position where the tangent of the negative electrode bending portion 236 intersects with the extension direction of the negative electrode flat portion 235.

[0113] Please refer to the following: Figure 1 and Figure 2 In this embodiment, the casing 10 of the cylindrical battery 1 includes a surrounding sidewall 12, and an opening 14 is formed at one end of the sidewall 12.

[0114] The cylindrical battery 1 also includes a cover plate 40 and a negative electrode current collector 62. The cover plate 40 is installed in the opening 14. The negative electrode current collector 62 is disposed between the electrode assembly 20 and the cover plate 40 and is electrically connected to the housing 10. One side of the connecting piece 621 of the negative electrode current collector 62 is welded to the negative electrode flat portion 235. In this way, by providing a reinforcing layer 24 covering a portion of the negative electrode upright portion 234, support force can be provided for the welding of the negative electrode current collector 62, avoiding insufficient welding contact force between the negative electrode tab 237 and the negative electrode current collector 62, which could lead to the generation of explosion points.

[0115] The cylindrical battery 1 also includes an insulating seal 50, which surrounds the periphery of the cover plate 40 to insulate and seal the cover plate 40 and the housing 10.

[0116] The housing 10 also includes a crimping portion 30, which is formed at one end of the side wall 12 near the opening 14 and recessed into the housing 10; the other side of the connecting piece 621 of the negative electrode current collector 62 is welded to the crimping portion 30. In this way, by setting the connecting piece 621 of the negative electrode current collector 62 to be located on the side of the crimping portion 30 facing the electrode assembly 20 and welded to the crimping portion 30, that is, the welding area of ​​the negative electrode current collector 62 with the electrode tab is located closer to the electrode assembly 20 than the crimping portion 30, thereby preventing the crimping portion 30 from affecting the welding area between the electrode tab and the negative electrode current collector 62, thereby improving the welding strength between the electrode tab and the negative electrode current collector 62.

[0117] Furthermore, the housing 10 also includes an end wall 11, and a side wall 12 is disposed around the end wall 11 and located at the end of the side wall 12 away from the opening 14. The end wall 11 and the side wall 12 enclose a receiving cavity 13 within the housing 10 for accommodating the electrode assembly 20, electrolyte, and other necessary battery components. The connection between the end wall 11 and the side wall 12 can be achieved in various ways, such as integral stamping, integral casting, or separate welding.

[0118] The cylindrical battery 1 also includes a terminal 70 that passes through the end wall 11 and is insulated from the end wall 11 by an insulator 80.

[0119] The cylindrical battery 1 also includes a positive current collector 61. The positive current collector 61 is disposed between the electrode assembly 20 and the end wall 11; the negative current collector 62 is disposed between the electrode assembly 20 and the cover plate 40. In this embodiment, the positive current collector 61 corresponds to the positive electrode tab 217, and the positive electrode tab 217 is electrically connected to the terminal post 70 through the positive current collector 61; the negative current collector 62 corresponds to the negative electrode tab 237, and the negative electrode tab 237 is electrically connected to the housing 10 through the negative current collector 62.

[0120] In this embodiment, the welding sequence of the positive current collector 61 and negative current collector 62 of the cylindrical battery 1 to the electrode assembly 20 is as follows: First, place the positive current collector 61; then, press the electrode assembly 20 together on both the positive and negative sides (the pressing process can increase the contact between the current collector and the electrode assembly 20 and avoid poor welding); the positive current collector 61 is welded using line welding instead of spot welding. This is because the negative electrode tab 237 is relatively soft, and after two pressings, the negative current collector 62 and the electrode assembly 20 will be closer together. Spot welding would cause the separator 22 to be burned due to concentrated heat. Wire welding has less heat and can avoid burning the separator 22, which would cause a short circuit between the positive and negative electrodes; next, place the negative current collector 62; press the electrode assembly 20 together on both the positive and negative sides again; finally, weld the negative current collector 62.

[0121] The cylindrical battery 1 in this embodiment has advantages such as high energy density, long cycle life and good safety performance.

[0122] In this embodiment, the negative electrode tab 237 is a folded tab. When welding the tabs and current collector of the cylindrical battery 1, the pretreatment steps for the tabs include two different methods: one is a flattening tab treatment method, and the other is the folded tab treatment method used for the negative electrode tab 237 in this embodiment. Similarly, the positive electrode tab 217 is also a folded tab.

[0123] like Figure 9 As shown, this utility model also provides a battery pack 100, which includes the aforementioned cylindrical battery 1. In one embodiment of the battery pack 100, the battery pack 100 includes a housing 110, a cover 120, and multiple cylindrical batteries 1. The multiple cylindrical batteries 1 are placed in the housing 110 and connected in series or parallel, or a combination of series and parallel connections. The cover 120 seals the housing 110 to protect the multiple cylindrical batteries 1. It should be noted that, in addition to the cylindrical battery 1 of this utility model, the battery pack 100 may also include a thermal management system, circuit board, etc. The battery pack 100 can be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0124] like Figure 10As shown, this utility model also provides an electronic device 1000, which includes the aforementioned battery pack 100. A working part 300 is electrically connected to the battery pack 100 to obtain electrical power. As an example, the electronic device 1000 is a vehicle, which can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part 300 is the vehicle body, and the battery pack 100 is located at the bottom of the vehicle body, providing electrical power for the vehicle's operation or the operation of its internal electrical components. However, in other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part 300 can be a unit component capable of obtaining electrical power from the battery pack 100 and performing corresponding work, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electronic device 1000.

[0125] Example 2

[0126] like Figure 11 and Figure 12 As shown, the overall structure of the cylindrical battery 1 in this embodiment is basically the same as that in embodiment 1. The difference is that the cylindrical battery 1 in this embodiment does not include the pressing part in embodiment 1. Instead, the outer periphery of the cover plate 40, the end of the side wall 12 of the shell 10 near the opening 14, and the outer periphery of the connecting piece 621 of the negative electrode current collector 62 are connected by welding. That is, the outer periphery of the cover plate 40, one end of the shell 10, and the outer periphery of the connecting piece 621 of the negative electrode current collector 62 are directly connected together by welding. On the one hand, this makes the connection between the three more solid; on the other hand, it enables the one-step welding assembly of the negative electrode current collector 62, the cover plate 40, and the shell 10, thereby improving the production efficiency of the battery.

[0127] Furthermore, in conjunction with the reinforcing layer 24 mentioned above covering a portion of the negative electrode upright portion 234, the strength of the negative electrode tab 237 is increased by setting the reinforcing layer 24, thereby increasing the distance between the welding area and the diaphragm 22 and preventing the diaphragm 22 from being burned during welding of the three.

[0128] Specifically, the outer periphery of the cover plate 40, the end of the housing 10, and the outer periphery of the connecting piece 621 are fused together by laser welding.

[0129] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A cylindrical battery, characterized in that, It includes: case; An electrode assembly is housed within the housing. The electrode assembly includes a positive electrode sheet, a separator, and a negative electrode sheet stacked and wound together to form a wound structure. The positive electrode sheet includes a positive current collector, and the negative electrode sheet includes a negative current collector. Along the height direction of the wound structure, the negative current collector includes a negative electrode coated active material region covered by a negative electrode active material layer and a negative electrode uncoated active material region not covered by the negative electrode active material layer. The uncoated active material region of the negative electrode includes a vertical negative electrode portion disposed along the height direction, a flat negative electrode portion disposed radially along the winding structure, and a negative electrode bend portion connecting the vertical negative electrode portion and the flat negative electrode portion; At least a portion of the negative electrode upright portion is covered with a reinforcing layer. The reinforcing layer includes a first edge close to the area of ​​the negative electrode coated with active material and a second edge away from the area of ​​the negative electrode coated with active material. Along a predetermined direction from the area of ​​the negative electrode coated with active material to the area of ​​the negative electrode uncoated with active material, the second edge extends beyond the membrane by a distance d1, where the value of d1 ranges from 0.2 mm to 3 mm.

2. The cylindrical battery as described in claim 1, characterized in that, Along the preset direction, the distance by which the diaphragm extends beyond the region of the negative electrode coated with active material is d2, and the value of d1 / d2 ranges from 0.2 to 0.

8.

3. The cylindrical battery as described in claim 1, characterized in that, The grayscale value of the reinforcing layer is 0-192.

4. The cylindrical battery as described in claim 1, characterized in that, Along the radial direction of the winding structure, the negative electrode upright includes a first negative electrode side away from the central hole of the winding structure and a second negative electrode side facing the central hole, wherein at least a portion of the first negative electrode side and / or the second negative electrode side is covered by the reinforcing layer.

5. The cylindrical battery as described in claim 1, characterized in that, The thickness of the negative electrode current collector is less than or equal to 5.5 μm and greater than or equal to 4 μm.

6. The cylindrical battery as described in claim 1, characterized in that, At least a portion of the uncoated active material area of ​​the negative electrode forms a negative electrode tab, and along the winding direction of the winding structure, two adjacent negative electrode tabs have a predetermined spacing. The negative electrode tab is in the shape of a trapezoid, with the lower base of the trapezoid located near the area of ​​the negative electrode coated with active material, and the end of the negative electrode tab near the area of ​​the negative electrode coated with active material is covered with the reinforcing layer.

7. The cylindrical battery according to any one of claims 1-6, characterized in that, The housing includes surrounding sidewalls, one end of which is formed with an opening; The cylindrical battery also includes: Cover plate, installed in the opening; A negative electrode current collector is disposed between the electrode assembly and the cover plate and is electrically connected to the housing. One side of the connecting piece of the negative electrode current collector is welded to the flat part of the negative electrode.

8. The cylindrical battery as described in claim 7, characterized in that, The housing also includes a crimping portion formed at one end of the side wall near the opening and recessed into the housing. The other side of the connecting piece of the negative electrode current collector is welded to the crimping part; or, The outer periphery of the cover plate, the end of the side wall of the housing near the opening, and the outer periphery of the connecting piece of the negative electrode current collector are connected by welding.

9. A battery pack, characterized in that, The cylindrical battery includes any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the battery pack as described in claim 9.

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