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 comprises: a housing, which comprises a shell and a cover plate, the cover plate covers the opening of the shell, and the cover plate is provided with an explosion-proof valve; the electrode assembly is accommodated in the shell; the current collecting component is in welded connection with the tabs of the electrode assembly and is provided with a plurality of welding areas which are arranged around a central hole of the current collecting component at intervals, each welding area comprises a plurality of welding marks, each welding area is provided with a first end adjacent to the central hole, and each welding mark comprises a second end adjacent to the central hole; a shortest distance H is formed between the first ends of the two adjacent welding areas in the direction around the center hole, and H is larger than or equal to 0.12 D and smaller than or equal to 0.17 D. The flow collecting component further comprises a through groove formed around the center hole, the through groove penetrates through the flow collecting component in the thickness direction of the flow collecting component, the shortest distance T is formed between the first end of the through groove and the center hole in the radial direction of the flow collecting component, and T is larger than or equal to 0 and smaller than or equal to 0.04 3D. According to the technical scheme, at least the flow collecting component can be effectively opened during pressure relief.

Description

Technical Field

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

[0002] In the field of new energy power batteries, secondary batteries generally include electrode components, a casing, and current collectors. The electrode components consist of positive and negative electrode plates, and a separator located between them. These positive and negative electrode plates and the separator are stacked and wound to form the electrode components, which are then encapsulated within the casing. Secondary batteries typically have current collectors at both ends of the electrode components within the casing. One end of the current collector is welded to the casing or end cap, and the other end is electrically connected to the tabs of the electrode components, thus achieving electrical connection between the casing and the electrode components. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery, battery pack and electronic device, so as to enable the current collector to open effectively when the pressure is released, so as to improve the safety performance of the battery.

[0004] To achieve the above objectives, this utility model provides a secondary battery, comprising: a casing, including a housing and a cover plate, one end of the housing forming an opening, the cover plate covering the opening and connected to the housing, and an explosion-proof valve provided on the cover plate; an electrode assembly, housed within the casing, the electrode assembly including tabs facing the cover plate; a current collector, welded to the tabs and having multiple welding areas formed by welding to the tabs and facing the cover plate, the multiple welding areas being arranged at intervals around a central hole of the current collector, each welding area including multiple weld marks, each welding area having a first end adjacent to the central hole, wherein the first ends of two adjacent welding areas along the direction surrounding the central hole have a minimum distance H, 0.12D≤H≤0.17D, where D is the outer diameter of the housing, the current collector also includes a through groove arranged around the central hole, the through groove penetrating the current collector in the thickness direction, the through groove having a first end adjacent to the central hole, and along the radial direction of the current collector, the first end of the through groove and the central hole having a minimum distance T, 0≤T≤0.043D.

[0005] In some embodiments, along the radial direction of the manifold, the first end of each welded area has a minimum distance L between it and the central hole, where L ≥ 0.043D.

[0006] In some embodiments, the through groove includes a first through groove and a second through groove disposed radially on opposite sides of the central hole along the flow collecting member. The projections of the first through groove and the second through groove along the axial direction of the central hole have a first shape and a second shape, respectively, wherein the first shape and the second shape are arranged asymmetrically with respect to the center of the central hole.

[0007] In some embodiments, at least one of the first shape and the second shape is an irregular shape.

[0008] In some embodiments, the through groove further has a second end away from the central hole, and the flow collecting member further includes a through hole disposed between the second end of the through groove and the edge of the flow collecting member. The through hole penetrates the flow collecting member in the thickness direction, and the second end of the through groove and the through hole have a minimum distance C, 0≤C≤0.043D.

[0009] In some embodiments, along the axial direction of the central hole, the projection of the explosion-proof valve onto the surface of the manifold facing the cover plate is a closed ring, and the portion of the closed ring located between two adjacent through holes is a bent root, the arc length of which is less than 1 / 5 of the circumference of the closed ring.

[0010] In some embodiments, the shortest distance T = 0, such that the through groove is connected to the central hole, and the through groove extends radially.

[0011] In some embodiments, the projection of the second end along the axial direction of the central hole includes a first line segment inclined relative to the longitudinal extension direction of the through slot, and the projection of the through hole along the axial direction of the central hole includes a second line segment opposite to and parallel to the first line segment.

[0012] Embodiments of this application also provide a battery pack including any of the above-described secondary batteries.

[0013] Embodiments of this application also provide an electronic device including the battery pack described above.

[0014] The beneficial technical effects of this utility model are as follows:

[0015] The technical solution of this application configures the shortest distance H between the first end of the adjacent welding area of ​​the current collector and the center hole to satisfy 0.12D≤H≤0.17D, and configures the shortest distance T between the first end of the through groove and the center hole to satisfy 0≤T≤0.043D. This can ensure that the current collector can be fully opened when depressurization is performed, thus ensuring smooth depressurization and avoiding affecting battery performance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A perspective view of a secondary battery according to an embodiment of this application is shown.

[0018] Figure 2 A front view of a secondary battery according to an embodiment of this application is shown.

[0019] Figure 3 A secondary battery according to an embodiment of this application is shown. Figure 2 A cross-sectional view of line X1-X1 in the diagram.

[0020] Figures 4 to 10 A top view schematic diagram of a current collection component according to several different embodiments of this application is shown.

[0021] Figure 11 A schematic diagram of an electronic device according to an embodiment of this application is shown when it is a vehicle. Detailed Implementation

[0022] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0023] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0024] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.

[0025] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0026] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0027] When the internal pressure of the secondary battery casing reaches a certain level, the explosion-proof valve on the cover plate will rupture to release the internal pressure and prevent the secondary battery from exploding from the casing. When the explosion-proof structure ruptures to release pressure, it is desirable that the current collector located in the pressure relief path can completely rupture and open to ensure smooth pressure relief. However, because the current collector on one side of the cover plate needs to be welded to the tabs of the electrode assembly, the current collector in existing technology may not be able to fully open when the explosion-proof valve ruptures to release pressure, thus hindering the pressure relief process and affecting the battery's safety performance.

[0028] Figure 1 A perspective view of a secondary battery 100 according to an embodiment of this application is shown. Figure 2 A front view of a secondary battery 100 according to an embodiment of this application is shown. Figure 3 A secondary battery 100 according to an embodiment of this application is shown. Figure 2 The cross-sectional view is shown along line X1-X1. In this embodiment, a cylindrical battery is shown as an example for the secondary battery 100. In some embodiments, the secondary battery 100 may be a 4680 cylindrical battery (46 mm in diameter, 80 mm in height), a 4695 cylindrical battery (46 mm in diameter, 95 mm in height), or a 46120 cylindrical battery (46 mm in diameter, 120 mm in height). Here, the diameter refers to the outer diameter of the casing.

[0029] See also Figures 1 to 3 The secondary battery 100 may include a cylindrical battery. The secondary battery 100 includes a casing, which comprises a housing 110 and a cover plate 140. The housing 110 may specifically include an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The side wall 112 may be cylindrical or follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111.

[0030] Specifically, the diameter of the housing 110 can be determined according to the specific size of the electrode assembly 130, such as 18mm, 21mm, 46mm, etc. The housing 110 and the cover plate 140 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the housing 110 and the cover plate 140 from rusting during long-term use, a layer of anti-rust material such as metallic nickel can be plated on the surface of the housing 110 and the cover plate 140.

[0031] An opening 113 is formed at one end of the side wall 112 opposite to the end wall 111, and a cover plate 140 is closed over the opening 113. The electrode assembly 130 is housed within the space defined by the housing 110 and the cover plate 140, and is used to house the electrode assembly 130, electrolyte, and other battery-essential components.

[0032] The electrode assembly 130 can be mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material, the positive active material being coated on the surface of the positive current collector; the positive current collector includes a coated area with active material and an uncoated area without active material, the uncoated area being wound to form the positive electrode tab of the electrode assembly 130. The negative electrode sheet includes a negative current collector and a negative active material, the negative active material being coated on the surface of the negative current collector; the negative current collector includes a coated area with active material and an uncoated area without active material, the uncoated area being wound to form the negative electrode tab of the electrode assembly 130. Taking a lithium-ion secondary battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the electrode assembly 130, an insulating film can be wrapped around the outside of the electrode assembly 130. The insulating film can be synthesized from PP, PE, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other polymer materials.

[0033] Electrode assembly 130 may include a first tab 131 facing opening 113 and a second tab 132 facing end wall 111. Terminal 120 may pass through end wall 111 and be insulated from end wall 111. Electrical insulation between terminal 120 and end wall 111 of housing 110 can be achieved in various ways. For example, insulation can be achieved by placing an insulating washer between terminal 120 and end wall 111. Terminal 120 may be made of a conductive metallic material. For example, the material of terminal 120 may be aluminum (Al).

[0034] In this embodiment, the first tab 131 is a negative tab, and the opening 113 side of the housing 110 is electrically connected to the first tab 131, thus carrying a negative charge. The second tab 132 can be a positive tab, and the terminal 120 is electrically connected to the second tab 132, carrying a positive charge. The first current collector 150 is disposed at the end of the electrode assembly 130 facing the opening 113, and the first tab 131 can be connected to the housing 110 through the first current collector 150. The first current collector 150 can be welded to the first tab 131. The second tab 132 can be electrically connected to the terminal 120 through the second current collector 160. In embodiments where the secondary battery is a cylindrical battery, the electrode assembly 130 can have a central through hole 133. The central through hole 133 can maintain smoother communication between the spaces at both ends of the electrode assembly 130, and can be used as an exhaust path for the gas generated by the electrode assembly 130 during operation.

[0035] The materials of the first current collector 150 and the second current collector 160 can be selected according to the polarity of the tabs they are connected to. For example, if the second current collector 160 is connected to the positive tab, the second current collector 160 can be made of aluminum, and the material of the first current collector 150 connected to the negative tab can be made of copper.

[0036] An explosion-proof valve 1413 may also be installed on the cover plate 140. The explosion-proof valve 1413 is used to at least partially open when the internal air pressure of the housing 110 reaches a certain level, so as to release the pressure inside the housing 110. The type of explosion-proof valve 1413 is not limited. Figure 3 In the illustrated embodiment, the explosion-proof valve 1413 includes grooves on the cover plate 140, with the grooves located on the side of the cover plate 140 facing the electrode assembly 130. The grooves can be annular. It should be noted that the annular structure is not limited to a circular or elliptical ring. Of course, in other embodiments, the grooves can also be other structures, as long as they can open when the pressure exceeds a set threshold. The explosion-proof valve 1413 with grooves is located in a weaker area of ​​the cover plate 140. When the air pressure inside the housing 110 exceeds a certain threshold, the weaker groove will rupture, allowing the air pressure inside the housing 110 to escape from the rupture, thereby preventing the secondary battery from exploding from the housing.

[0037] In this embodiment, the cover plate 140 and the side wall 112 are not integral. In other embodiments, the positions of the cover plate 140 and the end wall 111 can be interchanged, such that the cover plate 140 and the side wall 112 are integral. The cover plate 140 is located on the positive electrode side of the electrode assembly and is used for pressure relief from the positive electrode side.

[0038] Figure 4This is a top view schematic diagram of a current collector 150A according to an embodiment of this application. In this embodiment, the current collector is the first current collector described above, which is connected to the negative electrode tab of the electrode assembly. In the following description, the first current collector will be simply referred to as the current collector. It should also be understood that, for clarity of illustration, Figure 4 All structures on the flow collector are not shown, such as through slots.

[0039] As described above, the current collector 150A is welded to the corresponding tab of the electrode assembly (e.g., by laser penetration welding), therefore the current collector 150A can have a facing cover plate 140 formed by welding (see...). Figure 3 Multiple welding areas 152 are provided. These welding areas 152 can be arranged at intervals around the central hole 154 of the current collector 150A. The central hole 154 of the current collector 150A can be coaxially arranged with the central through hole 133 of the electrode assembly. Each welding area 152 can extend radially along the current collector 150A. In this embodiment, four welding areas 152 are provided around the central hole 154, and the four welding areas 152 are evenly arranged around the central hole 154. Each welding area 152 is a rectangular shape with rounded corners. Each welding area includes multiple solder marks, which can be solder joints or solder lines depending on the specific welding process.

[0040] Each welded area 152 has a first end 152a adjacent to the central hole 154 and a second end 152b distant from the central hole 154. It should be understood that the first end 152a adjacent to the central hole 154 refers to the boundary of the welded area 152 closest to the central hole 154. Figure 4 In the illustrated embodiment, the first end 152a is the short side of the welding area 152 closest to the center hole 154. In other embodiments, the first end 152a may also be an endpoint (e.g., Figure 7 The welding areas 152A and 152B in this application). The ends of other components in this application also have similar meanings.

[0041] Along the direction surrounding the central hole 154, the shortest distance between the first ends 152a of two adjacent welding areas 152 is H. According to an embodiment of this application, 0.12D≤H≤0.17D, where D is the outer diameter of the electrode assembly of the secondary battery. If H is less than 0.12D, the solder marks in the welding area 152 will be too dense in the central region of the current collector 150A, resulting in excessive tension between the current collector and the tab in the central region. This will resist the current collector from folding or tearing outward during pressure relief, preventing the current collector from opening. If H is greater than 0.17D, the tab of the electrode assembly in the central region may not be directly connected to the current collector, leading to an increase in the electron flow path in the inner ring near the central region, resulting in increased internal resistance and affecting battery performance. In the embodiment of this application, configuring H as 0.12D≤H≤0.17D ensures that the current collector can be fully opened during pressure relief, ensuring smooth pressure relief and avoiding impact on battery performance.

[0042] Figure 5 This is a top view of a current collection member 150B according to another embodiment of this application. Figure 5 A plurality of through slots 158 are shown arranged around the central hole 154. The through slots 158 penetrate the manifold 150B in the thickness direction. Each through slot 158 ​​may extend longitudinally in the radial direction of the manifold 150B. Each through slot 158 ​​may be located between two adjacent welding areas 152. In this plan view perpendicular to the axial direction of the central hole 154, each through slot 158 ​​may have the same shape. Each through slot 158 ​​may be arranged radially symmetrically with another through slot 158 ​​on the opposite side of the central hole 154 along the radial direction of the manifold 150B.

[0043] The through groove 158 has a first end 158a adjacent to the central hole 154 and a second end 158b distant from the central hole 154. The shortest distance T between the first end 158a of the through groove 158 and the central hole 154 along the radial direction of the manifold 150B. In some embodiments, T satisfies: 0 ≤ T ≤ 0.043D. Compared to the first end 152a of the welding region 152, the first end 158a of the through groove 158 can be closer to the central hole 154.

[0044] If T is greater than 0.043D, the solid width of the flow collector 150 between the first end 158a of the through groove 158 and the central hole 154 will be large, which may cause the flow collector to be unable to tear completely during pressure relief, thus making it impossible to open. In the embodiments of this application, T is configured to 0≤T≤0.043D, which can ensure that the flow collector can be fully opened during pressure relief, ensuring smooth pressure relief.

[0045] Along the radial direction of the manifold 150B, the shortest distance between the first end 152a of each welded area 152 and the central hole 154 is L. In some embodiments, the shortest distance L satisfies: L ≥ 0.043D. If L is less than 0.043D, the welded area between the manifold 150B and the tab may be too large, causing the manifold to fail to fully open during pressure relief. In the embodiments of this application, L is configured to be L ≥ 0.043D, which ensures that the manifold can fully open during pressure relief, guaranteeing smooth pressure relief.

[0046] In some embodiments, the radius of the central hole 154 is R, where R can satisfy: R≤0.15D. When the cylindrical battery is a 46-series cylindrical battery, i.e., the diameter of the casing is 46mm, 0mm≤R≤7mm. In such embodiments, for example, it should satisfy: 5.5mm≤H≤8mm, and L≥2mm.

[0047] Figure 6 This is a top view of a current collection member 150C according to another embodiment of this application. (See reference) Figure 6 As shown, with Figure 5 The difference in the illustrated embodiment is that the through grooves include through grooves 158a, 158b, 158c, and 158d arranged radially along the collector member 150C on opposite sides of the central hole. Through grooves 158a and 158c are arranged radially along the collector member 150C on opposite sides of the central hole 154, and through grooves 158b and 158d are arranged radially along the collector member 150C on opposite sides of the central hole 154.

[0048] In this embodiment, the through slots 158a, 158b, 158c, and 158d have different irregular shapes in the plan view. Through slot 158d has a rectangular shape. Each of the through slots 158a, 158b, 158c, and 158d extends radially along the collector member 150C. The through slots 158a and 158c, which are arranged opposite to each other, have different shapes, and their shapes are asymmetrical with respect to the center of the central hole 154. Similarly, the through slots 158b and 158d, which are arranged opposite to each other, also have different shapes, and their shapes are asymmetrical with respect to the center of the central hole 154. By configuring the through slots on opposite sides of the central hole 154 in an asymmetrical arrangement, this asymmetrical arrangement easily generates shear and torsional forces during the tearing process of the collector member. Compared to symmetrically arranged through slots, the asymmetrical arrangement makes the collector member easier to tear. This ensures that the manifold can be fully opened during depressurization, guaranteeing smooth depressurization.

[0049] Figure 7This is a top view of a flow collector 150D according to another embodiment of this application. It shows other optional structures for the welding area and the through groove. Reference Figure 7 As shown, the manifold member 150D has welding regions 152A, 152B, 152C, and 152D. The shapes of the welding regions 152A, 152B, 152C, and 152D can be different. In this embodiment, welding region 152C is rectangular, and welding region 152D is rhomboid. Welding regions 152A and 152B are shapes composed of a combination of rectangles and triangles. In other embodiments, each welding region of the manifold member can have any other shape, and this application is not limited thereto. Furthermore, the through groove of the manifold member 150D can also have any suitable shape. Figure 7 The shapes of the through slots 158a and 158c shown are merely examples.

[0050] Figure 8 This is a top view of a current collection member 150E according to another embodiment of this application. (See reference) Figure 8 As shown, the manifold 150E may also include a plurality of through holes 162, each through hole 162 being located between the second end 158b of each through groove 158 and the edge of the manifold 150E. Each through hole 162 is also located between two adjacent welding areas 152. The through holes 162 may have any suitable shape. Figure 7 The shape shown is merely an example and is not intended to limit the scope of this application. By providing the through-hole 162, the weight of the current collector 150E can be reduced, and it also facilitates the wetting of the electrolyte in the secondary battery.

[0051] The second end 158b of the through groove 158 has a minimum distance C between it and the through hole 162. In some embodiments, the minimum distance C satisfies 0 ≤ C ≤ 0.043D. If C is greater than 0.043D, the solid width of the current collecting member 150 between the second end 158b of the through groove 158 and the through hole 162 will be large, which may cause the current collecting member to be unable to be completely torn apart during pressure relief, thus making it impossible to open the current collecting member.

[0052] Compared to the welding area in the prior art (example size 6mm × 12mm), an example of this application improves the size of the welding area 152 to 6mm × 9mm. This allows the shortest distance L between the first end 152a of the welding area 152 and the central hole 154 to satisfy L ≥ 0.043D, and the shortest distance H between the first ends 152a of adjacent welding areas 152 to satisfy 0.12D ≤ H ≤ 0.17D. Furthermore, the shortest distance T between the first end 158a of the through groove 158 and the central hole 154 also satisfies 0 ≤ T ≤ 0.043D. According to simulation verification, compared to the prior art, the failure pressure of the current collector 150E in this embodiment can be reduced by approximately 18%, meaning the current collector is more easily torn. This ensures that the current collector can fully open during pressure relief, guaranteeing smooth pressure release.

[0053] also, Figure 8 The surface of the manifold 150E shown in the top view faces the cover plate 140 (see top view). Figure 3 ) surface, Figure 8 The explosion-proof valve 1413 is also shown (see Figure 3 The projection Pa on this surface is along the axial direction of the central hole 154. The projection Pa can be a circular or elliptical closed ring. The portion Pa' of the projection Pa between two adjacent through holes 162 can be referred to as the bend root, because when the manifold 150E tears, it will fold along this portion Pa' (bend root). The arc length of the portion Pa' between two adjacent through holes 162 can be reduced by increasing the size of the through holes 162. In some embodiments, the arc length of this portion Pa' is less than 1 / 5 of the circumference of the projection Pa. By reducing the arc length of the portion Pa' (bend root) to less than 1 / 5 of the circumference of the projection Pa, the span of the bend root is reduced, making it easier to fold along the portion Pa' after the manifold 150E tears, ensuring that the manifold can be fully opened during depressurization.

[0054] Figure 9 This is a top view of the current collection member 150F according to another embodiment of this application. (See reference) Figure 9 As shown, with Figure 8 The difference in the illustrated embodiment is that the shortest distance T = 0 between the through groove 158 and the central hole 154 of the manifold 150F, making the through groove 158 and the central hole 154 connected. Simulation verification shows that, compared to the prior art, the failure pressure of the manifold 150F in this embodiment can be reduced by approximately 17.7%, and the manifold is more easily torn. This ensures that the manifold can fully open during pressure relief, guaranteeing smooth pressure release.

[0055] Figure 10 This is a top view schematic diagram of a current collector 150G according to another embodiment of this application. (See reference) Figure 10 As shown in the top plan view, the second end 158b of the through groove 158 includes a first segment s1 inclined relative to the longitudinal extension direction of the through groove 158 (e.g., the radial direction of the collector member). The through hole 162 includes a second segment s2 opposite to and parallel to the first segment s1. Thus, a portion of the collector member 150G between the first segment s1 and the second segment s2 is arranged inclined (not perpendicular) relative to the radial direction of the collector member.

[0056] According to simulation verification, the failure pressure of current collector 150G can be further improved compared to current collectors 150E and 150F in the above embodiments. Specifically, the failure pressure of current collector 150G can be reduced by approximately 24.8% compared to the prior art. Therefore, compared to current collectors 150E and 150F in the above embodiments, current collector 150G is more easily torn, thereby further ensuring that the current collector can be fully opened during pressure relief, ensuring smooth pressure relief.

[0057] Embodiments of this application also provide a battery pack 1002, including a secondary battery 100 as described above, and the battery pack 1002 may have the beneficial effects described above regarding the secondary battery 100.

[0058] Embodiments of this application also provide an electronic device 1000, including the aforementioned battery pack 1002, and the electronic device 1000 can have the beneficial effects described above regarding the secondary battery 100 and / or battery pack 1002. For ease of explanation, the following embodiments use a vehicle as an example to illustrate the electronic device 1000. Figure 11 A schematic diagram of an electronic device according to an embodiment of this application is shown when it is a vehicle.

[0059] See Figure 11The vehicle has a battery pack 1002 installed inside, which can be located at the bottom, front, or rear of the vehicle body. The battery pack 1002 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. The vehicle 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 is the vehicle body, and the battery pack 1002 is located at the bottom of the vehicle body, providing electrical power for the vehicle's movement or the operation of its internal electrical components. However, in some 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 can obtain electrical energy from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner's 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.

[0060] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A secondary battery characterized by comprising: Comprising: a housing including a case and a cover plate, one end of the case forming an opening, the cover plate covering the opening and connected to the case, the cover plate being provided with an explosion-proof valve; an electrode assembly accommodated in the housing, the electrode assembly including a tab facing the cover plate; a current collecting member welded to the tab and having a plurality of tab-facing welded areas formed by welding to the tab, the plurality of welded areas being spaced around a central hole of the current collecting member, each of the welded areas including a plurality of welds, each of the welded areas having a first end adjacent to the central hole, wherein a shortest distance H between the first ends of two adjacent welded areas in a direction around the central hole is 0.12D≤H≤0.17D, where D is an outer diameter dimension of the case, the current collecting member further including a through groove arranged around the central hole, the through groove penetrating the current collecting member in a thickness direction of the current collecting member, the through groove having a first end adjacent to the central hole, a shortest distance T between the first end of the through groove and the central hole in a radial direction of the current collecting member being 0≤T≤0.043D. 2.The secondary battery of claim 1, wherein a shortest distance L between the first end of each of the welded areas and the central hole in the radial direction of the current collecting member is L≥0.043D. 3.The secondary battery of claim 1, wherein the through groove includes a first through groove and a second through groove disposed on opposite sides of the central hole in the radial direction of the current collecting member, projections of the first through groove and the second through groove in an axial direction of the central hole respectively having a first shape and a second shape, wherein the first shape and the second shape are asymmetrically arranged with respect to a center of the central hole. 4.The secondary battery of claim 3, wherein the first shape and the second shape are different. 5.The secondary battery of claim 1, wherein the through groove further has a second end away from the central hole, the current collecting member further including a through hole disposed between the second end of the through groove and an edge of the current collecting member, the through hole penetrating the current collecting member in the thickness direction of the current collecting member, a shortest distance C between the second end of the through groove and the through hole is 0≤C≤0.043D. 6.The secondary battery of claim 5, wherein a projection of the explosion-proof valve on a surface of the current collecting member facing the cover plate in the axial direction of the central hole is a closed loop, a section of the closed loop between adjacent two through holes is a bent root, and an arc length of the bent root is less than 1 / 5 of a circumference of the closed loop. 7.The secondary battery of claim 5, wherein the shortest distance T=0, such that the through groove communicates with the central hole, the through groove extends longitudinally in the radial direction. 8.The secondary battery of claim 7, wherein A projection of the second end of the through groove along an axial direction of the central hole includes a first line segment inclined with respect to a longitudinal extension direction of the through groove, and a projection of the through hole along the axial direction of the central hole includes a second line segment opposite to and parallel with the first line segment.

9. A battery pack characterized by comprising: A secondary battery including any one of claims 1 to 8.

10. An electronic device, comprising: A battery pack including claim 9.

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