Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device. The secondary battery includes: a case; the electrode assembly is accommodated in the shell and comprises a winding structure formed by winding a first electrode plate, a diaphragm and a second electrode plate; along the height direction, a first electrode current collector of the first electrode plate comprises a first electrode coating area and a first electrode non-coating area; along the winding direction, the first electrode non-coating area sequentially comprises a first electrode non-tab-out starting area, a first electrode tab-out area and a first electrode non-tab-out ending area; the first tab is bent towards the direction of a central hole of the winding structure, a first accommodating space is formed between the bent first tab and the initial region of the first electrode without the tab, and a supporting piece is arranged in the first accommodating space. By arranging the supporting piece, the outer side area, not extending out of the tab starting area, of the first electrode in the height direction is supported, the area can serve as an effective welding area, and therefore the area of the effective welding area is increased.

Description

Technical Field

[0001] This utility model relates to a secondary battery, a battery pack, and an electronic device. Background Technology

[0002] In existing technology, the electrode assembly of a secondary battery includes a spiral structure formed by stacking and winding a positive electrode, a separator, and a negative electrode. Because the inner ring of this spiral structure lacks tabs to avoid obstructing the central hole, after the tabs are cut and flattened (the middle ring tabs bend towards the central hole), the lack of tabs on the inner ring acts as a support, making this area prone to laser welding breakage. Therefore, this area is not an effective welding area, reducing the effective welding area for laser welding and resulting in a smaller effective welding area. This reduces the welding process window and leads to poor performance. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defect in the prior art that the inner ring of the winding structure has no tabs, resulting in a small effective welding area, and to provide a secondary battery, battery pack and electronic device.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] A secondary battery, characterized in that it comprises:

[0006] case;

[0007] An electrode assembly is housed within the housing. The electrode assembly includes a first electrode sheet, a diaphragm, and a wound structure formed by stacking and winding a second electrode sheet. The first electrode sheet includes a first electrode current collector. Along the height direction of the wound structure, the first electrode current collector includes a first electrode coated area covered by a first electrode active material layer and a first electrode uncoated area not covered by the first electrode active material layer.

[0008] Along the winding direction of the winding structure, the uncoated area of ​​the first electrode sequentially includes the first electrode tabless starting area, the first electrode tabless area, and the first electrode tabless ending area; the first electrode tabless area includes the first tab, and neither the first electrode tabless starting area nor the first electrode tabless starting area includes the first tab.

[0009] The first electrode tab is a folded electrode tab. The first electrode tab is bent toward the central hole of the winding structure. A first receiving space is formed between the bent first electrode tab and the first electrode not exiting the electrode tab starting area. A support member is provided in the first receiving space.

[0010] In this technical solution, by setting a support member in the first accommodating space, the support member can support the outer area along the height direction of the first electrode's un-exited tab starting area, so that this area can be used as an effective welding area, thereby increasing the effective welding area area, ensuring the welding process window, and thus improving the yield.

[0011] Preferably, along the height direction of the winding structure, the orthographic projection of the support member does not overlap with the central hole.

[0012] Preferably, the second electrode sheet includes a second electrode current collector; along the height direction of the winding structure, the second electrode current collector includes a second electrode coated area covered by the second electrode active material layer and a second electrode uncoated area not covered by the second electrode active material layer;

[0013] Along the winding direction of the winding structure, the uncoated area of ​​the second electrode sequentially includes the starting area of ​​the second electrode not exiting the tab, the exit area of ​​the second electrode, and the ending area of ​​the second electrode not exiting the tab; the exit area of ​​the second electrode includes the second tab, while the starting area and the ending area of ​​the second electrode not exiting the tab do not include the second tab;

[0014] The second electrode tab is a folded electrode tab. The second electrode tab is bent toward the central hole of the winding structure. A second receiving space is formed between the bent second electrode tab and the starting area of ​​the second electrode before it exits the electrode tab. The support member is provided in the second receiving space.

[0015] Preferably, the support member is a ring-shaped structure.

[0016] Preferably, the inner diameter of the annular structure is 5mm-10mm; and / or,

[0017] The ratio of the inner diameter of the annular structure to the diameter of the central hole of the winding structure is 0.4-1.6; and / or,

[0018] The diameter of the central hole in the winding structure is 4mm-8mm.

[0019] Preferably, along the height direction of the winding structure, the size of the support member is 100μm~500μm; and / or,

[0020] The support member is made of an insulating material; and / or,

[0021] The support member is covered with an adhesive layer on at least one side along the height direction of the winding structure.

[0022] Preferably, along the height direction of the winding structure, the side of the first tab closest to the center hole of the winding structure abuts against the side of the support member away from the starting area of ​​the first electrode before it exits the tab.

[0023] Preferably, the housing includes a surrounding sidewall, one end of which is formed with an opening; the end of the housing near the opening includes a press-fit portion recessed into the housing.

[0024] The secondary battery also includes:

[0025] Cover plate, installed in the opening;

[0026] An insulating seal is provided around the periphery of the cover plate to insulate and seal the cover plate and the housing;

[0027] A collector plate is disposed between the electrode assembly and the cover plate and is electrically connected to the housing. The connecting piece of the collector plate is located on the side of the crimping part facing the electrode assembly and is welded to the crimping part.

[0028] And / or,

[0029] The secondary battery is a cylindrical battery;

[0030] And / or,

[0031] The first electrode is a negative electrode.

[0032] A battery pack characterized in that it includes a secondary battery as described above.

[0033] An electronic device characterized in that it includes a battery pack as described above.

[0034] The positive and progressive effects of this utility model are as follows:

[0035] This invention provides a support member within the first accommodating space formed between the first electrode tab after bending and the starting area of ​​the first electrode not extending beyond the electrode tab. This support member provides support to the outer region along the height direction of the starting area of ​​the first electrode not extending beyond the electrode tab, enabling this region to serve as an effective welding area. This increases the effective welding area, ensures the welding process window, and thus improves the yield rate. Attached Figure Description

[0036] Figure 1 This is a cross-sectional view of a secondary battery according to a preferred embodiment of the present invention.

[0037] Figure 2 for Figure 1 A magnified schematic diagram of part A in the middle.

[0038] Figure 3 This is a three-dimensional structural diagram of the electrode assembly of a secondary battery according to a preferred embodiment of the present invention.

[0039] Figure 4 This is a cross-sectional view of the electrode assembly of a secondary battery according to a preferred embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the structure of the first electrode sheet of a secondary battery in a preferred embodiment of the present invention when it is not wound.

[0041] Figure 6 This is a partial cross-sectional view (I) of the electrode assembly of a secondary battery according to a preferred embodiment of the present invention.

[0042] Figure 7 This is a schematic diagram of the structure of the second electrode sheet of a secondary battery in a preferred embodiment of the present invention when it is not wound.

[0043] Figure 8 This is a partial cross-sectional view (II) of the electrode assembly of a secondary battery according to a preferred embodiment of the present invention.

[0044] Figure 9 This is a partial cross-sectional view (III) of the electrode assembly of a secondary battery according to a preferred embodiment of the present invention.

[0045] Figure 10 This is a top view of the support structure of a secondary battery according to a preferred embodiment of the present invention.

[0046] Figure 11 This is a partial cross-sectional view of the first electrode sheet of a single coil in a secondary battery according to a preferred embodiment of the present invention.

[0047] Figure 12 This is a partial cross-sectional view of the second electrode sheet of a single coil in a secondary battery according to a preferred embodiment of the present invention.

[0048] Figure 13 This is a schematic diagram of the battery pack structure according to a preferred embodiment of the present invention.

[0049] Figure 14 This is a schematic diagram of the structure of an electronic device according to a preferred embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures

[0051] Electronic devices 1000

[0052] Battery pack 100

[0053] Work Department 300

[0054] Box 310

[0055] Box lid 320

[0056] Secondary battery 1

[0057] Casing 10

[0058] Side wall 11

[0059] Opening 12

[0060] end wall 13

[0061] Electrode assembly 20

[0062] 201 winding structure

[0063] Center Hole 2011

[0064] First electrode plate 21

[0065] First electrode current collector 211

[0066] First electrode active material layer 2111

[0067] First electrode coating area 212

[0068] Uncoated area 213 of the first electrode

[0069] The first electrode has not yet left the starting area of ​​the electrode ear 214

[0070] First electrode outlet region 215

[0071] First Pole Ear 2151

[0072] First electrode connection region 2152

[0073] The first electrode did not exit the electrode end area 216

[0074] The first electrode plate starts at position 217.

[0075] The first electrode plate ends at position 218.

[0076] First accommodation space 219

[0077] Diaphragm 22

[0078] Diaphragm starting position 221

[0079] Diaphragm termination position 222

[0080] Second electrode plate 23

[0081] Second electrode current collector 231

[0082] Second electrode active material layer 2311

[0083] Second electrode coating area 232

[0084] Uncoated area 233 of the second electrode

[0085] The second electrode did not exit the starting area of ​​the electrode ear 234

[0086] Second electrode outlet region 235

[0087] Second pole ear 2351

[0088] Second electrode connection region 2352

[0089] The second electrode did not exit the electrode end area 236

[0090] The second electrode plate starts at position 237.

[0091] The second electrode plate ends at position 238.

[0092] Second accommodation space 239

[0093] Insulation layer 24

[0094] Insulating film 25

[0095] Support component 26

[0096] crimping part 30

[0097] Cover plate 40

[0098] Insulating seal 50

[0099] First Collector Disk 61

[0100] Second collection disk 62

[0101] 70 pole

[0102] Height direction H of the winding structure

[0103] Radial R of the wound structure

[0104] The winding direction P of the wound structure

[0105] The inner diameter f1 of the ring structure

[0106] The diameter of the center hole is f3

[0107] The dimension h of the support member along the height direction of the winding structure Detailed Implementation

[0108] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0109] In existing technology, the electrode assembly of a secondary battery includes a spiral structure formed by stacking and winding a positive electrode, a separator, and a negative electrode. Because the inner ring of this spiral structure lacks tabs to avoid obstructing the central hole, after the tabs are cut and flattened (the middle ring tabs bend towards the central hole), the lack of tabs on the inner ring acts as a support, making this area prone to laser welding breakage. Therefore, this area is not an effective welding area, reducing the effective welding area for laser welding and resulting in a smaller effective welding area. This reduces the welding process window and leads to poor performance.

[0110] like Figure 1 and Figure 2 As shown, this embodiment provides a secondary battery 1. The secondary battery 1 includes a housing 10 and an electrode assembly 20, the electrode assembly 20 being housed within the housing 10.

[0111] like Figure 3 and Figure 4 As shown, the electrode assembly 20 includes a wound structure 201 formed by stacking and winding a first electrode sheet 21, a diaphragm 22, and a second electrode sheet 23. The first electrode sheet 21 includes a first electrode current collector 211; along the height direction H of the wound structure 201, the first electrode current collector 211 includes a first electrode coated area 212 covered by the first electrode active material layer 2111 and a first electrode uncoated area 213 not covered by the first electrode active material layer 2111.

[0112] like Figure 5 , Figure 6 and Figure 9 As shown, along the winding direction P of the winding structure 201, the uncoated area 213 of the first electrode includes, in sequence, the first electrode tabless starting area 214, the first electrode tabless area 215, and the first electrode tabless ending area 216; the first electrode tabless area 215 includes the first tab 2151, while the first electrode tabless starting area 214 and the first electrode tabless ending area 216 do not include the first tab 2151.

[0113] The first electrode tab 2151 is a folded electrode tab. The first electrode tab 2151 is bent toward the central hole 2011 of the winding structure 201. A first receiving space 219 is formed between the bent first electrode tab 2151 and the first electrode not exiting the electrode tab starting area 214. A support member 26 is provided in the first receiving space 219.

[0114] In this way, by setting the support member 26 in the first accommodating space 219, the support member 26 can support the outer region along the height direction H of the first electrode not exiting the tab starting area 214, so that this region can be used as an effective welding area, thereby increasing the effective welding area area, ensuring the welding process window, and thus improving the yield.

[0115] Preferably, along the height direction H of the winding structure 201, the orthographic projection of the support member 26 does not overlap with the central hole 2011, so as to avoid obstructing the central hole 2011 and affecting the exhaust function of the central hole 2011.

[0116] like Figure 7 , Figure 8 As shown, the second electrode sheet 23 includes a second electrode current collector 231; along the height direction H of the winding structure 201, the second electrode current collector 231 includes a second electrode coated area 232 covered by the second electrode active material layer 2311 and a second electrode uncoated area 233 not covered by the second electrode active material layer 2311.

[0117] Along the winding direction P of the winding structure 201, the uncoated area 233 of the second electrode includes, in sequence, the starting area 234 of the second electrode not exiting the tab, the exit area 235 of the second electrode, and the ending area 236 of the second electrode not exiting the tab; the exit area 235 of the second electrode includes the second tab 2351, while the starting area 234 and the ending area 236 of the second electrode not exiting the tab do not include the second tab 2351.

[0118] The second electrode tab 2351 is a folded electrode tab. The second electrode tab 2351 is bent toward the central hole 2011 of the winding structure 201. A second accommodating space 239 is formed between the bent second electrode tab 2351 and the second electrode not exiting the electrode tab starting area 234.

[0119] In this embodiment, the first electrode sheet 21 is a negative electrode sheet, and correspondingly, the first electrode tab 2151 is a negative electrode tab; the second electrode sheet 23 is a positive electrode sheet, and correspondingly, the second electrode tab 2351 is a positive electrode tab. Since the metal part of the positive electrode sheet is typically made of aluminum, and the metal part of the negative electrode sheet is typically made of copper, the hardness of the metal part of the positive electrode sheet is higher than that of the metal part of the negative electrode sheet. That is, the hardness of the negative electrode tab of the negative electrode sheet is lower than the hardness of the positive electrode tab of the positive electrode sheet. Therefore, providing the support member 26 within the first receiving space 219 is more conducive to supporting the outer region along the height direction H of the negative electrode sheet's non-exit electrode starting area (the first electrode non-exit tab starting area 214). In other embodiments, the first electrode sheet 21 may be a positive electrode sheet, and the second electrode sheet 23 may be a negative electrode sheet.

[0120] In this embodiment, the support member 26 is provided only in the first receiving space 219, but it is not limited to this. In other embodiments, the support member 26 may be provided only in the second receiving space 239. Alternatively, the support member 26 may be provided in both the first receiving space 219 and the second receiving space 239 at both ends of the winding structure 201 along the height direction H, so that it can simultaneously support the outer regions of the first electrode not exiting the tab starting region 214 and the second electrode not exiting the tab starting region 234 located at both ends of the winding structure 201 along the height direction H.

[0121] Preferably, along the height direction H of the winding structure 201, the side of the first tab 2151 near the center hole 2011 of the winding structure 201 abuts against the side of the support member 26 away from the first electrode tab initiation area 214, so that the support member 26 can support the outer region of the first electrode tab initiation area 214 along the height direction to the maximum extent, thereby increasing the effective welding area.

[0122] Specifically, the support member 26 has a ring-shaped structure. This provides better support while the inner hole in the middle of the ring structure prevents it from obstructing the central hole 2011.

[0123] Please refer to the following: Figure 9 and Figure 10 Preferably, the inner diameter f1 of the annular structure is 5mm-10mm, for example, it can be 5mm, 6mm, 6.5mm, 7.5mm, 9.3mm or 10mm. By limiting the range of the inner diameter f1 of the annular structure, on the one hand, it avoids the inner diameter f1 of the annular structure being too small, which would block the central hole 2011 and thus affect the venting of the central hole 2011; on the other hand, it avoids the inner diameter f1 of the annular structure being too large, which would affect the support strength.

[0124] The ratio of the inner diameter f1 of the annular structure to the diameter f3 of the central hole 2011 of the winding structure 201 is 0.4-1.6, for example, it can be 0.4, 0.5, 0.95, 1, 1.3, or 1.6. By limiting the range of this ratio, on the one hand, it avoids the inner diameter f1 of the annular structure being too small, which would block the central hole 2011 and thus affect the venting of the central hole 2011; on the other hand, it avoids the inner diameter f1 of the annular structure being too large, which would affect the support strength.

[0125] The aperture f3 of the central hole 2011 of the winding structure 201 is 4mm-8mm, for example, it can be 4mm, 5mm, 5.5mm, 6mm, 7.3mm or 8mm. By limiting the range of the aperture f3 of the central hole 2011 of the winding structure 201, on the one hand, it avoids the aperture f3 of the central hole 2011 being too large, which would affect the overall energy density of the secondary battery 1; on the other hand, it avoids the aperture f3 of the central hole 2011 being too small, which would make winding difficult.

[0126] Preferably, the dimension h of the support member 26 along the height direction H of the winding structure 201 is 100μm to 500μm, for example, it can be 100μm, 140μm, 250μm, 300μm, 395μm, or 500μm. By limiting the range of the dimension h of the support member 26 along the height direction H of the winding structure 201, on the one hand, it is avoided that the dimension h is too small and cannot play a supporting role; on the other hand, it is avoided that the dimension h is too large and affects the overall energy density of the secondary battery 1.

[0127] In this embodiment, the material of the support member 26 is an insulating material. For example, the material of the support member 26 is one of silicone, PP (polypropylene), PEPE (polyethylene), or PET (polyethylene terephthalate).

[0128] The support member 26 is covered with an adhesive layer on at least one side along the height direction H of the winding structure 201 to facilitate the assembly and fixation of the support member 26.

[0129] In this embodiment, when the first electrode sheet 21 is unwound (when the first electrode sheet 21 is unfolded), along the winding direction P of the winding structure 201, the positions of the first electrode not exiting the tab start area 214, the first electrode exiting the tab area 215, and the first electrode not exiting the tab end area 216 are as follows: Figure 5 As shown; and after the winding structure 201 is formed, the positions of the first electrode not exiting the tab starting area 214, the first electrode exiting the tab area 215, and the first electrode not exiting the tab ending area 216 are as follows: Figure 6 As shown. Similarly, when the second electrode sheet 23 is unwound (when the second electrode sheet 23 is unfolded), that is, in the state before winding, along the winding direction P of the winding structure 201, the positions of the second electrode not exiting the tab start area 234, the second electrode exiting the tab area 235, and the second electrode not exiting the tab end area 236 are as follows: Figure 7 As shown; and after the winding structure 201 is formed, the positions of the second electrode not exiting the tab starting area 234, the second electrode exiting the tab area 235, and the second electrode not exiting the tab ending area 236 are as follows: Figure 8 As shown.

[0130] Please refer to the following: Figure 4 In the winding structure 201, the second electrode sheet 23 includes a starting position 237 and a ending position 238; the first electrode sheet 21 includes a starting position 217 and an ending position 218; and the separator 22 includes a starting position 221 and an ending position 222. The winding structure 201 is also covered with an insulating film 25, which can be synthesized from PP, PE, PET, PVC, or other polymer materials. The axial direction of the central hole 2011 is the same as the axial direction of the winding structure 201, and the axial direction of the winding structure 201 is in the same direction as the height direction H of the secondary battery 1. The separator 22 is made of insulating material, specifically PP (polypropylene) or PE (polyethylene), etc.

[0131] like Figure 11 As shown, the first electrode tab region 215 includes a first tab 2151 and a first electrode connection region 2152 connecting the first tab 2151 and the first electrode coating region 212. Figure 12 As shown, the second electrode outlet region 235 includes a second electrode tab 2351 and a second electrode connection region 2352 connecting the second electrode tab 2351 and the second electrode coating region 232.

[0132] In this embodiment, the housing 10 contains one electrode assembly 20, but it is not limited to this. In other embodiments, the housing 10 may also contain two, three, four or other values ​​of electrode assemblies 20, which can be adjusted according to design needs.

[0133] The second electrode connection region 2352 includes a first side away from the central hole 2011 of the winding structure 201 along a radial direction R, and a second side close to the central hole 2011. At least a portion of the first side and / or the second side is covered with an insulating layer 24. Thus, by covering at least a portion of the first side and / or the second side of the second electrode connection region 2352 with an insulating layer 24, the risk of deformation of the second electrode connection region 2352 can be reduced, and the insulation performance of the second electrode connection region 2352 can be improved, thereby significantly improving the safety and reliability of the battery performance. The insulating layer 24 is mainly composed of boehmite and PVDF (polyvinylidene fluoride). The boehmite accounts for 80%, and the PVDF accounts for 20%. The thickness of the insulating layer 24 is 1.5μm-2.5μm, for example, it can be 1.5μm, 1.7μm, 2μm, 2.1μm, 2.3μm, or 2.5μm. By setting the thickness range of the insulating layer 24, it is possible to avoid the insulating layer 24 being too thin, which would make it difficult to obtain the required electrical insulation and support strength; at the same time, it is also possible to avoid the insulating layer 24 being too thick, which would lead to a longer curing time for the coating layer and an increase in the overall thickness of the structure. Preferably, the thickness of the insulating layer 24 is 2 μm.

[0134] Please refer to the following: Figure 12 In this embodiment, both the first and second sides of the second electrode connection region 2352 are covered with an insulating layer 24. However, this is not a limitation; in other embodiments, only the first side of the second electrode connection region 2352 may be covered with the insulating layer 24, or only the second side of the second electrode connection region 2352 may be covered with the insulating layer 24. Adjustments can be made according to design requirements.

[0135] Please refer to the following: Figure 1 and Figure 2In this embodiment, the housing 10 includes a surrounding sidewall 11, one end of which has an opening 12; the end of the housing 10 near the opening 12 includes a crimping portion 30 recessed into the housing 10. The secondary battery 1 also includes a cover plate 40, an insulating seal 50, and a current collector. The cover plate 40 is mounted on the opening 12. The insulating seal 50 surrounds the periphery of the cover plate 40 to insulate and seal the cover plate 40 and the housing 10. The current collector is disposed between the electrode assembly 20 and the cover plate 40 and is electrically connected to the housing 10. The connecting piece of the current collector is located on the side of the crimping portion 30 facing the electrode assembly 20 and is welded to the crimping portion 30. In this way, by setting the connecting piece of the current collector plate to be located on the side of the crimping part 30 facing the electrode assembly 20 and welded to the crimping part 30, that is, the welding area of ​​the current collector plate and the electrode tab is located closer to the electrode assembly 20 than the crimping part 30, the influence of the crimping part 30 on the welding area of ​​the electrode tab and the current collector plate can be prevented, thereby improving the welding strength of the electrode tab and the current collector plate.

[0136] Furthermore, the housing 10 also includes an end wall 13, and a side wall 11 is disposed around the end wall 13 and located at the end of the side wall 11 away from the opening 12. The end wall 13 and the side wall 11 enclose a receiving cavity within the housing 10 for accommodating the electrode assembly 20, electrolyte, and other necessary battery components. The connection between the end wall 13 and the side wall 11 can be achieved in various ways, such as integral stamping, integral casting, or separate welding.

[0137] The secondary battery 1 also includes a terminal post 70, which passes through the end wall 13 and is insulated from the end wall 13.

[0138] The current collector includes a first current collector 61 and a second current collector 62. The first current collector 61 is disposed between the electrode assembly 20 and the end wall 13; the second current collector 62 is disposed between the electrode assembly 20 and the cover plate 40. In this embodiment, the first current collector 61 corresponds to the second tab 2351 (positive tab), and the second tab 2351 is electrically connected to the electrode post 70 through the first current collector 61; the second current collector 62 corresponds to the first tab 2151 (negative tab), and the first tab 2151 is electrically connected to the housing 10 through the second current collector 62. However, this is not a limitation. In other embodiments, the first current collector 61 may correspond to the first tab 2151, and the second current collector 62 may correspond to the second tab 2351.

[0139] In this embodiment, the secondary battery 1 is a cylindrical battery. Cylindrical batteries have advantages such as high energy density, long cycle life, and good safety performance. However, it is not limited to this; in other embodiments, the secondary battery 1 can also be a prismatic battery or other shaped batteries.

[0140] Applying the specific structure of the support member 26 in this embodiment to a cylindrical battery, that is, placing the support member 26 within the first accommodating space 219 formed between the bent first tab 2151 and the first electrode not extending beyond the tab starting area 214, the support member 26 can support the outer region along the height direction H of the first electrode not extending beyond the tab starting area 214, so that this region can serve as an effective welding area, thereby increasing the effective welding area, ensuring the window for the welding process, and thus improving the yield.

[0141] As described above, in this embodiment, the first tab 2151 is a folded tab. When welding the tabs and current collector of the cylindrical battery, the pretreatment steps of the tabs include two different processing methods: one is the flattening tab processing method, and the other is the folded tab processing method used for the first tab 2151 in this embodiment.

[0142] In this embodiment, the welding sequence of the first current collector 61 and the second current collector 62 of the secondary battery 1 to the electrode assembly 20 is as follows: First, place the first current collector 61; then, press the electrode assembly 20 together on both sides of the first and second electrodes (the pressing process can increase the contact between the current collector and the electrode assembly 20 and avoid poor welding); the first current collector 61 is welded using line welding instead of spot welding. This is because the first tab 2151 (negative electrode tab) is relatively soft. After two pressings, the second current collector 62 and the electrode assembly 20 will be closer together. Spot welding would cause the diaphragm 22 to be burned due to concentrated heat. Wire welding has less heat and can avoid burning the diaphragm 22, which would cause a short circuit between the positive and first electrodes; next, place the second current collector 62; press the electrode assembly 20 together on both sides of the first and second electrodes again; finally, weld the second current collector 62.

[0143] like Figure 13 As shown, this utility model also provides a battery pack 100, which includes the aforementioned secondary battery 1. In one embodiment of the battery pack 100, the battery pack 100 includes a housing 310, a cover 320, and multiple secondary batteries 1. The multiple secondary batteries 1 are placed in the housing 310 and connected in series or parallel, or a combination of series and parallel connections. The cover 320 seals the housing 310 to protect the multiple secondary batteries 1. It should be noted that, in addition to the secondary battery 1 of this utility model, the battery pack 100 may also include a battery pack 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.

[0144] like Figure 14As 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.

[0145] 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 secondary battery, characterized in that, It includes: case; An electrode assembly is housed within the housing. The electrode assembly includes a first electrode sheet, a diaphragm, and a wound structure formed by stacking and winding a second electrode sheet. The first electrode sheet includes a first electrode current collector. Along the height direction of the wound structure, the first electrode current collector includes a first electrode coated area covered by a first electrode active material layer and a first electrode uncoated area not covered by the first electrode active material layer. Along the winding direction of the winding structure, the uncoated area of ​​the first electrode sequentially includes the first electrode tabless starting area, the first electrode tabless area, and the first electrode tabless ending area; the first electrode tabless area includes the first tab, while the first electrode tabless starting area and the first electrode tabless ending area do not include the first tab. The first electrode tab is a folded electrode tab. The first electrode tab is bent toward the central hole of the winding structure. A first receiving space is formed between the bent first electrode tab and the first electrode not exiting the electrode tab starting area. A support member is provided in the first receiving space.

2. The secondary battery as described in claim 1, characterized in that, Along the height direction of the winding structure, the orthographic projection of the support member does not overlap with the central hole.

3. The secondary battery as described in claim 1, characterized in that, The second electrode sheet includes a second electrode current collector; along the height direction of the winding structure, the second electrode current collector includes a second electrode coated area covered by the second electrode active material layer and a second electrode uncoated area not covered by the second electrode active material layer; Along the winding direction of the winding structure, the uncoated area of ​​the second electrode sequentially includes the starting area of ​​the second electrode not exiting the tab, the exit area of ​​the second electrode, and the ending area of ​​the second electrode not exiting the tab; the exit area of ​​the second electrode includes the second tab, while the starting area and the ending area of ​​the second electrode not exiting the tab do not include the second tab; The second electrode tab is a folded electrode tab. The second electrode tab is bent toward the central hole of the winding structure. A second receiving space is formed between the bent second electrode tab and the starting area of ​​the second electrode before it exits the electrode tab. The support member is provided in the second receiving space.

4. The secondary battery as described in claim 1, characterized in that, The support component is a ring-shaped structure.

5. The secondary battery as described in claim 4, characterized in that, The inner diameter of the annular structure is 5mm-10mm; and / or, The ratio of the inner diameter of the annular structure to the diameter of the central hole of the winding structure is 0.4-1.6; and / or, The diameter of the central hole in the winding structure is 4mm-8mm.

6. The secondary battery as described in claim 1, characterized in that, Along the height direction of the winding structure, the dimensions of the support member are 100μm~500μm; and / or, The support member is made of an insulating material; and / or, The support member is covered with an adhesive layer on at least one side along the height direction of the winding structure.

7. The secondary battery as described in claim 1, characterized in that, Along the height direction of the winding structure, the side of the first tab closest to the center hole of the winding structure abuts against the side of the support member away from the starting area of ​​the first electrode before it exits the tab.

8. The secondary battery according to any one of claims 1-7, characterized in that, The housing includes a surrounding sidewall, one end of which is formed with an opening; the end of the housing near the opening includes a press-fit portion recessed into the housing. The secondary battery also includes: Cover plate, installed in the opening; An insulating seal is provided around the periphery of the cover plate to insulate and seal the cover plate and the housing; A collector plate is disposed between the electrode assembly and the cover plate and is electrically connected to the housing. The connecting piece of the collector plate is located on the side of the crimping part facing the electrode assembly and is welded to the crimping part. And / or, The secondary battery is a cylindrical battery; And / or, The first electrode is a negative electrode.

9. A battery pack, characterized in that, The secondary 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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