Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a kind of secondary battery, battery pack and electronic device;The secondary battery includes: shell, cover plate, electrode assembly and current collecting member;Shell includes side wall, and side wall is formed at least one opening around in circumference direction;Cover plate blocks at least one opening;Electrode assembly is housed in shell, and one side of electrode assembly has tab;Current collecting member is set between electrode assembly and cover plate, and current collecting member includes first connecting part and second connecting part, and first connecting part is welded with tab, and second connecting part surrounds the outer periphery of first connecting part and is annular;Second connecting part extends towards the outside of shell, is clamped between side wall and cover plate, and second connecting part, side wall and cover plate are connected by welding mark, and welding mark covers the end of second connecting part away from electrode assembly, the end of side wall away from electrode assembly and cover plate, and the melting width of welding mark is T, the thickness of second connecting part is D, T is 1.1D, can improve the anti-vibration impact capacity of secondary battery, reduce welding failure risk.

Description

Technical Field

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

[0002] Current secondary batteries typically have a current collector located near the opening of the casing. This current collector is welded to the side wall of the casing and to the tabs of the electrode assembly. When the secondary battery is subjected to vibration and impact, the electrode assembly causes axial vibration displacement of the current collector within the battery, which can easily pull on the welded joint between the current collector and the casing, posing a risk of weld failure. Especially in designs where the outer edge of the current collector is fully enclosed by welding, there is a pressing need to optimize the welding design of the current collector to improve the secondary battery's resistance to vibration and impact and reduce the risk of weld failure. Utility Model Content

[0003] This invention provides a secondary battery, a battery pack, and an electronic device to improve the vibration and shock resistance of the secondary battery and reduce the risk of welding failure.

[0004] This utility model provides a secondary battery, which includes: a shell, a cover plate, an electrode assembly, and a current collector; the shell includes a side wall, and the side wall forms at least one opening in the circumferential direction; the cover plate seals at least one opening; the electrode assembly is housed in the shell, and the electrode assembly has a tab on the side facing the cover plate; the current collector is disposed between the electrode assembly and the cover plate, and the current collector includes a first connecting part and a second connecting part, the first connecting part is welded to the tab, and the second connecting part surrounds the outer periphery of the first connecting part and is annular; at least a portion of the second connecting part extends along the inner wall of the shell toward the outer side of the shell and is clamped between the outer periphery of the side wall and the cover plate, the second connecting part, the side wall and the cover plate are connected by a solder joint, the solder joint covers the end of the second connecting part facing away from the electrode assembly, the end of the side wall facing away from the electrode assembly and the cover plate, the weld width is T, the thickness of the second connecting part is D, and T≥1.1D.

[0005] In one embodiment of the secondary battery of this utility model, the current collector further includes a buffer portion. On the cross section through the axis of the cover plate, the end of the second connecting portion away from the solder mark is defined as the first end, and the end of the first connecting portion located on the radially outer side is defined as the second end. Along the axial direction of the cover plate, the first end is closer to the electrode assembly than the second end, and the buffer portion connects the first end and the second end.

[0006] In one embodiment of the secondary battery of this utility model, the buffer part is an annular inclined wall. On the cross section through the axis of the cover plate, the angle between the inclined wall and the plane where the first connecting part is located is α, where 15°<α≤45°.

[0007] In one embodiment of the secondary battery of this utility model, the cover plate includes a third connecting portion disposed on the outer periphery. The third connecting portion extends along the axial direction of the cover plate, and the outer periphery of the third connecting portion abuts against the second connecting portion and is connected by soldering.

[0008] In one embodiment of the secondary battery of this utility model, the cover plate further includes a body portion and a transition portion. The body portion is located at the center of the cover plate. On a cross section through the axis of the cover plate, the two ends of the transition portion are defined as the third end and the fourth end. The third end is connected to the end of the third connecting portion near the electrode assembly, and the fourth end is connected to the outer periphery of the body portion. Along the axial direction of the cover plate, the third end is closer to the electrode assembly than the fourth end.

[0009] In one embodiment of the secondary battery of this utility model, along the axial direction of the cover plate, the first end is closer to the electrode assembly than the third end, and the second end is closer to the fourth end of the electrode assembly, so that the transition part and the buffer part are spaced apart, and the end of the second connecting part away from the electrode assembly, the end of the side wall away from the electrode assembly and the end of the cover plate away from the electrode assembly are flush.

[0010] In one embodiment of the secondary battery of this utility model, the first connecting part includes a plurality of tab connecting parts, which are arranged at intervals along the circumference of the current collector; the current collector also includes at least one thickness reduction part, which is disposed on at least one side of the two sides of the first connecting part along the thickness direction, and the thickness reduction part surrounds the radial outer side of the tab connecting part. The thickness reduction part is a closed ring or includes a plurality of arc-shaped thinning parts arranged at intervals along the circumference of the current collector.

[0011] In one embodiment of the secondary battery of this utility model, at least one arc-shaped thinning portion is provided on the radially outer side of each electrode connection portion.

[0012] This utility model also provides a battery pack, which includes any of the above-mentioned secondary batteries.

[0013] This invention also provides an electronic device that includes the aforementioned battery pack.

[0014] The beneficial effects of this utility model are as follows: The secondary battery proposed in this utility model, by providing at least a portion of the second connecting part extending outward along the inner wall of the casing and clamped between the outer periphery of the side wall and the cover plate, and connecting the second connecting part, the side wall, and the cover plate with the same weld mark, increases the contact area between the second connecting part and the side wall, and between the second connecting part and the cover plate, which is beneficial to improving welding quality. Furthermore, the weld width is T, and the thickness of the second connecting part is D, with T ≥ 1.1D. This arrangement ensures that the triple welding area of ​​the second connecting part, the side wall, and the cover plate has a larger molten pool cross-sectional area, thereby achieving the beneficial effects of improving the secondary battery's resistance to vibration and impact and reducing the risk of welding failure. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] In the attached diagram:

[0017] Figure 1 This is a schematic diagram of the structure of a secondary battery in one embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the electrode assembly in one embodiment of the secondary battery of this utility model;

[0019] Figure 3 This is an embodiment of the secondary battery of the present invention. Figure 1 A magnified view of a section at point A in the middle;

[0020] Figure 4 This is an embodiment of the secondary battery of the present invention. Figure 3 A magnified view of a section at point B in the middle;

[0021] Figure 5 This is an embodiment of the secondary battery of the present invention. Figure 3 A magnified view of a section at point B in the middle;

[0022] Figure 6 This is a partially enlarged view of the secondary battery in one embodiment of the present invention.

[0023] Figure 7 This is an embodiment of the secondary battery of the present invention. Figure 1 A magnified view of a section at point A in the middle;

[0024] Figure 8 This is an embodiment of the secondary battery of the present invention. Figure 7 A magnified view of a section at point C;

[0025] Figure 9 This is an embodiment of the secondary battery of the present invention. Figure 7 A magnified view of a section at point C;

[0026] Figure 10 This is a partially enlarged view of the secondary battery after removing the cover plate in one embodiment of the present invention.

[0027] Figure 11 This is a partially enlarged view of the secondary battery after removing the cover plate in one embodiment of the present invention.

[0028] Figure 12 This is a partially enlarged view of the secondary battery after removing the cover plate in one embodiment of the present invention.

[0029] Figure 13 This is a schematic diagram of the electrode assembly in one embodiment of the present invention;

[0030] Figure 14 This is a schematic diagram of the electronic device in one embodiment of the present invention.

[0031] The attached figures are labeled as follows:

[0032] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Housing; 102. Housing cover; 100. Secondary battery; 110. Casing; 111. End wall; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. First electrode; 1211. Negative current collector; 1212. First coated area; 1213. First uncoated area; 122. Separator; 123. Second electrode; 1231. Positive current collector; 1232. Second coated area; 1233. Second uncoated area; 124. First tab; 12 5. Second tab; 130. Current collector; 131. First connecting part; 1311. Second end; 1312. Tab connecting part; 132. Second connecting part; 1321. First end; 133. Buffer part; 1331. Inclined wall; 134. First recess; 135. Thickness reduction part; 1351. Arc-shaped thinning part; 140. Cover plate; 141. Third connecting part; 142. Body part; 143. Transition part; 1431. Third end; 1432. Fourth end; 144. Second recess; 150. Pole post; 160. Weld mark. Detailed Implementation

[0033] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0034] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0035] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0036] Please see Figures 1 to 14 This utility model provides a secondary battery 100, a battery pack 10, and an electronic device 1. In the secondary battery 100, at least a portion of a second connecting part 132 extends along the inner wall of the housing 110 toward the outer side of the housing 110 and is sandwiched between the side wall 112 and the outer periphery of the cover plate 140. The second connecting part 132, the side wall 112, and the cover plate 140 are connected by the same solder mark 160. The weld width of the solder mark 160 is T, and the thickness of the second connecting part 132 is D, with T ≥ 1.1D. This arrangement can improve the welding quality, thereby achieving the beneficial effects of improving the vibration and shock resistance of the secondary battery 100 and reducing the risk of welding failure.

[0037] Please see Figure 1 This utility model provides a secondary battery 100, which includes a cover plate 140, a shell 110, an electrode assembly 120, a current collector 130, and a terminal post 150.

[0038] Please see Figure 1 The housing 110 includes a sidewall 112 having at least one opening 113, and the sidewall 112 circumferentially surrounds a receiving cavity. The receiving cavity is used to accommodate an electrode assembly 120, an electrolyte (not shown), and other components. The receiving cavity has at least one opening 113 at each of its axial ends, and a cover plate 140 seals at least one opening 113. In one embodiment, the housing 110 has openings 113 at opposite ends of the receiving cavity, and each opening 113 is closed by an end cap. In this embodiment, the housing 110 has an opening 113 at one end of the receiving cavity, and the other end of the receiving cavity has an end wall 111 integrally formed with the surrounding sidewall 112, wherein the end wall 111 and the sidewall 112 are integrally stamped or integrally cast. The circumference of the sidewall 112 is not limited and can be cylindrical, cuboid or prism-shaped, or can be along any other closed-loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, the sidewall 112 is cylindrical and surrounds the outer edge of the end wall 111, and a circular opening 113 is formed at the end of the sidewall 112 away from the end wall 111. The end cap that closes the opening 113 is also circular.

[0039] Please see Figure 1 and Figure 2The electrode assembly 120 is disposed within the receiving cavity of the housing 110. The electrode assembly 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes a wound structure formed by stacking and winding a first electrode 121, a second electrode 123, and a separator 122. The first electrode 121 and the second electrode 123 have opposite polarities. In some embodiments, the first electrode 121 is a positive electrode and the second electrode 123 is a negative electrode. In other embodiments, the first electrode 121 is a negative electrode and the second electrode 123 is a positive electrode.

[0040] Please see Figure 1 and Figure 2 In this embodiment, the first electrode 121 is a negative electrode. The first electrode 121 includes a negative current collector 1211 and a negative active material. The negative active material is coated on the surface of the negative current collector 1211. The negative current collector 1211 includes a first coated area 1212 coated with active material and a first uncoated area 1213 uncoated with active material. The first uncoated area 1213 is located at the end of the first electrode 121. The first uncoated area 1213 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 to form an electrode tab. In order to distinguish the electrode tab formed by the second electrode 123, the electrode tab located on the first electrode 121 is called the first electrode tab 124. The first electrode tab 124 is the corresponding negative electrode tab.

[0041] Please see Figures 1 to 2 The second electrode 123 is a positive electrode. Specifically, the second electrode 123 includes a positive current collector 1231 and a positive active material. The positive active material is coated on the surface of the positive current collector 1231. The positive current collector 1231 includes a second coated area 1232 coated with active material and a second uncoated area 1233 uncoated with active material. The second uncoated area 1233 is located at the end of the second electrode 123. The other end of the second uncoated area 1233 extends out of the diaphragm 122 along the winding axis of the electrode assembly 120 and is bent toward the winding axis to form a second tab 125. The second tab 125 is the corresponding positive tab.

[0042] Please see Figures 1 to 2A separator 122 is disposed between the first electrode 121 and the second electrode 123 to isolate the positive electrode active material layer and the negative electrode active material layer. Taking a lithium-ion secondary battery 100 as an example, the positive electrode current collector 1231 can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector 1211 can be made of copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The substrate material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 120, an insulating film can also be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0043] Please see Figure 1 and Figure 2 Furthermore, if the first tab 124 faces the end wall 111 or the opening 113, then the second tab 125 faces the other end of the housing 110. In this embodiment, the second tab 125 faces the end wall 111 and is electrically connected to the post 150, making the post 150 positively charged. The first tab 124 faces the opening 113, and the housing 110 is electrically connected to the first tab 124, thus becoming negatively charged. However, in another embodiment, the first tab 124 can be connected to the post 150, and the second tab 125 can be connected to the housing 110.

[0044] Please see Figure 1 The secondary battery 100 also includes a terminal post 150, which is fixed to the end wall 111 and electrically connected to the electrode assembly 120. Specifically, the end wall 111 is provided with a terminal post hole, and the terminal post 150 is installed through the terminal post hole and insulated from the end wall 111. The end of the terminal post 150 facing the electrode assembly 120 passes through the end wall 111 and is directly electrically connected to the second electrode tab 125 or indirectly connected via a transfer connection. The structure of the terminal post 150 can be any suitable form that can pass through the end wall 111 and be electrically connected to the second electrode tab 125 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or an irregular contour that can achieve stable conductivity. The shape of the terminal post hole corresponds to the shape of the terminal post 150. In this embodiment, the cross-section of the terminal post 150 is circular.

[0045] Please see Figures 3 to 9The secondary battery 100 also includes a current collector 130, which is disposed between the electrode assembly 120 and the cover plate 140. The current collector 130 includes a first connecting portion 131 and a second connecting portion 132. The first connecting portion 131 is welded to the first tab 124 of the electrode assembly 120. The welding method can be ultrasonic welding, resistance welding, laser welding, etc., and is not limited thereto. In this embodiment, laser welding is used. The first tab 124 is the negative electrode tab, and copper is the preferred material for the current collector 130. It should be noted that the first connecting portion 131 is the part where the current collector 130 and the first tab 124 fit together. For example, it can be disc-shaped and can be used for welding the current collector 130 and the first tab 124. In order to improve the positioning, processing convenience, interchangeability and uniformity of the current collector 130 during installation, the first connecting portion 131 in this embodiment adopts a circular structure. The second connecting part 132 is arranged around the outer periphery of the first connecting part 131. The second connecting part 132 can be an integral closed ring structure or one or more arc-shaped structures, and there is no limitation on this.

[0046] Please see Figures 3 to 9 The second connecting portion 132 surrounds the outer periphery of the first connecting portion 131 and is annular, that is, the second connecting portion 132 is an annular closed structure. At least a portion of the second connecting portion 132 extends along the inner wall of the housing 110 toward the outer side of the housing 110 and is sandwiched between the side wall 112 and the outer periphery of the cover plate 140. That is, along the radial direction of the flow collecting member 130 from the inside to the outside, the cover plate 140, the second connecting portion 132 and the side wall 112 are arranged in sequence. The structure of the cover plate 140 can take many forms and is not limited thereto. For example, it can be disc-shaped or it can be a structure with an upward-turned outer periphery.

[0047] Please see Figures 3 to 5 In one embodiment of the secondary battery 100 of this utility model, the cover plate 140 includes a third connecting portion 141 disposed on the outer periphery, the third connecting portion 141 being along the axial direction of the cover plate 140 (e.g., Figure 3 Extending in the X direction, the outer periphery of the third connecting portion 141 abuts against the second connecting portion 132. The cover plate 140, the second connecting portion 132, and the side wall 112 are connected by a single weld 160, requiring only one welding process to achieve the welded connection of the cover plate 140, the second connecting portion 132, and the side wall 112, forming a triple-welded area. Compared to conventional embodiments where the cover plate 140 is welded separately to the current collector 130 and the housing 110, this process reduces the number of welding steps and improves assembly efficiency. Furthermore, please refer to... Figure 6Since the second connecting part 132 is a closed ring structure, the resulting solder mark 160 is also a closed ring. The solder mark 160 covers one end of the second connecting part 132 facing away from the electrode assembly 120, one end of the side wall 112 facing away from the electrode assembly 120, and the cover plate 140. The full ring of solder mark 160 makes the current collector 130, the housing 110 and the cover plate 140 electrically connected.

[0048] Please see Figure 5 The second connecting portion 132, the side wall 112, and the cover plate 140 are connected by a weld 160; the weld width of the weld 160 is T, and the thickness of the second connecting portion 132 is D, where T ≥ 1.1D. It should be noted that the weld width T of the weld 160 is the width of the weld 160 along the radial direction of the cover plate 140. This arrangement ensures that the triple-welded area has a larger molten pool cross-sectional area, thereby achieving the beneficial effects of improving the vibration and shock resistance of the secondary battery 100 and reducing the risk of welding failure.

[0049] Please see Figures 7 to 9 In one embodiment of the secondary battery 100 of this utility model, the current collector 130 further includes a buffer portion 133. On a cross-section passing through the axis of the cover plate 140, the end of the second connecting portion 132 facing away from the solder mark 160 is defined as the first end 1321, and the end of the first connecting portion 131 located radially outward is defined as the second end 1311. Along the axial direction of the cover plate 140, the first end 1321 is closer to the electrode assembly 120 than the second end 1311. The buffer portion 133 connects the first end 1321 and the second end 1311. The shape of the buffer portion 133 is not limited. The buffer portion 133 can be a straight inclined wall 1331, a wavy curved wall, or a combination of various shapes, as long as the buffer portion 133 can form a redundant structure. This configuration enables the electrode assembly 120 to drive the current collector 130 to generate axial displacement inside the secondary battery 100 under vibration conditions. The buffer part 133 can undergo local deformation under tensile force, thereby releasing stress and weakening the pull on the welded part between the current collector 130 and the shell 110. This improves the vibration and impact resistance of the secondary battery 100 and reduces the risk of welding failure.

[0050] Please see Figure 9 In one embodiment of the secondary battery 100 of this utility model, the buffer portion 133 is an annular inclined wall 1331. On a cross-section passing through the axis of the cover plate 140, the angle between the inclined wall 1331 and the plane containing the first connecting portion 131 is α, where 15° < α ≤ 45°. Compared to... Figure 5In the embodiment shown, the first end 1321 of the second connecting part 132 and the second end 1311 of the first connecting part 131 are at the same height. This arrangement allows the buffer part 133 between the second connecting part 132 and the first connecting part 131 to form a redundant structure, which plays a buffering role to resist the pulling of the welding part on the current collector 130 after the electrode assembly 120 is subjected to external force.

[0051] Please see Figure 8 The second connecting portion 132 and the buffer portion 133 can form a first recess 134 recessed towards the electrode assembly 120 and a protrusion formed on the side of the current collector 130 facing the electrode assembly 120. The first recess 134 can provide a larger accommodating space on the side of the current collector 130 facing the cover plate 140, which can avoid assembly interference.

[0052] Please see Figure 8 In one embodiment of the secondary battery 100 of this utility model, the cover plate 140 further includes a body portion 142 and a transition portion 143. The body portion 142 is located at the center of the cover plate 140. On a cross-section passing through the axis of the cover plate 140, the two ends of the transition portion 143 are defined as a third end 1431 and a fourth end 1432. The third end 1431 is connected to the end of the second connecting portion 132 near the electrode assembly 120, and the fourth end 1432 is connected to the outer periphery of the body portion 142. Along the axial direction of the cover plate 140, the third end 1431 is closer to the electrode assembly 120 than the fourth end 1432. In this design, the transition portion 143 and the second connecting portion 132 can form a second recess 144 recessed towards the electrode assembly 120. This arrangement can maximize the utilization of the accommodating space of the first recess 134. Preferably, the outer periphery of the third connecting part 141 is in an interference fit with the second connecting part 132. In this case, the third connecting part 141 has a radially outward elastic force, which is beneficial to press the second connecting part 132 to the side wall 112, thereby improving welding efficiency and welding quality.

[0053] Please see Figure 8 In one embodiment of the secondary battery 100 of this utility model, along the axial direction of the cover plate 140, the first end 1321 is closer to the electrode assembly 120 than the third end 1431, and the second end 1311 is closer to the electrode assembly 120 than the fourth end 1432. This allows the second recess 144 to be accommodated within the first recess 134. It can be understood that there is a gap between the first recess 134 and the second recess 144. The existence of this gap allows the second connecting part 132 to move upward as a whole without interfering with the cover plate 140. This achieves that the end of the second connecting part 132 facing away from the electrode assembly 120, the end of the side wall 112 facing away from the electrode assembly 120, and the end of the cover plate 140 facing away from the electrode assembly 120 are flush or substantially flush. This arrangement is beneficial to improving the reliability of welding, thereby improving the vibration and shock resistance of the secondary battery 100 and reducing the risk of welding failure.

[0054] Please see Figure 10 In one embodiment of the secondary battery 100 of this utility model, the first connecting portion 131 includes a plurality of tab connecting portions 1312, and the tab connecting portions 1312 are the areas in the first connecting portion 131 that are welded to the tabs. The plurality of tab connecting portions 1312 are arranged at intervals along the circumferential direction of the current collector 130. The number of tab connecting portions 1312 is not limited, but preferably, the plurality of tab connecting portions 1312 are arranged at equal intervals along the circumferential direction.

[0055] Please see Figures 10 to 13 The current collector 130 also includes at least one thickness reduction portion 135, which is disposed on at least one side of the two sides of the first connecting portion 131 along the thickness direction. The thickness reduction portion 135 surrounds the radial outer side of the tab connecting portion 1312. The thickness reduction portion 135 can form a gap on the first connecting portion 131. The gap can cause local deformation of the material when subjected to impact, thereby releasing stress and weakening the stress transmission between the tab connecting portion 1312 and the second connecting portion 132.

[0056] The thickness reduction portion 135 is a closed annulus or includes a plurality of arc-shaped thinning portions 1351 arranged circumferentially along the flow collector 130. For example, in one embodiment, such as Figure 10 As shown, a plurality of thickness-reducing portions 135 are provided on the side of the first connecting portion 131 facing the cover plate 140. Along the circumference of the current-collecting member 130, each thickness-reducing portion 135 includes a plurality of spaced-apart arc-shaped thinning portions 1351. At least one arc-shaped thinning portion 1351 is correspondingly provided on the radially outer side of each electrode tab connecting portion 1312. This arrangement can maximize the relief of stress on the electrode tab connecting portion 1312. Specifically, the first connecting portion 131 forms one or more laser weld marks by laser welding between the electrode tab connecting portion 1312 and the lower electrode tab. An arc-shaped thinning portion 1351 is correspondingly provided on the radially outer side of this laser weld mark. In another embodiment, as... Figure 11 As shown, with Figure 10 The difference in the illustrated embodiment is that the circumferential length of the thickness reduction portion 135 is larger, which allows for stress relief over a greater area. In some other embodiments, such as... Figure 12 As shown, the thickness reduction portion 135 is a closed ring. This thickness reduction portion 135 is simple to process and can release stress generated at any position in the circumferential direction of the current collector 130. All of the above features can release stress through the thickness reduction portion 135 when the secondary battery 100 experiences radial vibration, reducing the problem of continuous tearing of the solder mark 160 in the radial direction, which could lead to welding failure.

[0057] Please see Figure 13This utility model also provides a battery pack 10, which includes the secondary battery 100 described above. In one embodiment of the battery pack 10, the battery pack 10 includes a housing 101, a cover 102, and multiple secondary batteries 100. The multiple secondary batteries 100 are placed in the housing 101 and are connected in series or parallel, or a combination of series and parallel connections. The cover 102 covers the housing 101 to protect the multiple secondary batteries 100. It should be noted that, in addition to the secondary battery 100 of this utility model, the battery pack 10 may also include a battery pack thermal management system, circuit board, etc. The battery pack 10 can be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0058] Please see Figure 14 This utility model also provides an electronic device 1, which includes the aforementioned battery pack 10. A working unit 11 is electrically connected to the battery pack 10 to obtain electrical power. As an example, the electronic device 1 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 unit 11 is the vehicle body, and the battery pack 10 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 1 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, etc.; the working unit 11 can be a unit component capable of obtaining electrical power from the battery pack 10 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 1.

[0059] The beneficial effects of this utility model are as follows: The secondary battery proposed in this utility model, by providing at least a portion of the second connecting part extending outward along the inner wall of the casing and clamped between the outer periphery of the side wall and the cover plate, and connecting the second connecting part, the side wall, and the cover plate with the same weld mark, increases the contact area between the second connecting part and the side wall, and between the second connecting part and the cover plate, which is beneficial to improving welding quality. Furthermore, the weld width is T, and the thickness of the second connecting part is D, with T ≥ 1.1D. This arrangement ensures that the triple welding area of ​​the second connecting part, the side wall, and the cover plate has a larger molten pool cross-sectional area, thereby achieving the beneficial effects of improving the secondary battery's resistance to vibration and impact and reducing the risk of welding failure.

[0060] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A secondary battery, characterized in that, include: A housing, including sidewalls, said sidewalls forming at least one opening in the circumferential direction; Cover plate, sealing at least one of the openings; An electrode assembly is housed within the housing, and the electrode assembly has tabs on the side facing the cover plate; A current collector is disposed between the electrode assembly and the cover plate. The current collector includes a first connecting part and a second connecting part. The first connecting part is welded to the electrode tab, and the second connecting part surrounds the outer periphery of the first connecting part and is annular. At least a portion of the second connecting part extends outward along the inner wall of the housing and is sandwiched between the outer periphery of the side wall and the cover plate. The second connecting part, the side wall and the cover plate are connected by a solder joint. The solder joint covers the end of the second connecting part facing away from the electrode assembly, the end of the side wall facing away from the electrode assembly and the cover plate. The weld width of the solder joint is T, and the thickness of the second connecting part is D, where T≥1.1D.

2. The secondary battery according to claim 1, characterized in that, The current collection component also includes a buffer portion. On a cross section passing through the axis of the cover plate, the end of the second connection portion away from the solder mark is defined as the first end, and the end of the first connection portion located radially outward is defined as the second end. Along the axial direction of the cover plate, the first end is closer to the electrode assembly than the second end, and the buffer portion connects the first end and the second end.

3. The secondary battery according to claim 2, characterized in that, The buffer section is an annular inclined wall. On the cross section passing through the axis of the cover plate, the angle between the inclined wall and the plane where the first connecting part is located is α, where 15°<α≤45°.

4. The secondary battery according to claim 2, characterized in that, The cover plate includes a third connecting portion disposed on its outer periphery, the third connecting portion extending axially along the cover plate, the outer periphery of the third connecting portion abutting against the second connecting portion and being connected by the solder stamp.

5. The secondary battery according to claim 4, characterized in that, The cover plate also includes a body portion and a transition portion. The body portion is located at the center of the cover plate. On a cross section passing through the axis of the cover plate, the two ends of the transition portion are defined as a third end and a fourth end. The third end is connected to the end of the third connecting portion near the electrode assembly, and the fourth end is connected to the outer periphery of the body portion. Along the axial direction of the cover plate, the third end is closer to the electrode assembly than the fourth end.

6. The secondary battery according to claim 5, characterized in that, Along the axial direction of the cover plate, the first end is closer to the electrode assembly than the third end, and the second end is closer to the fourth end of the electrode assembly, such that the transition portion and the buffer portion are spaced apart, and the end of the second connecting portion facing away from the electrode assembly, the end of the sidewall facing away from the electrode assembly, and the end of the cover plate facing away from the electrode assembly are flush.

7. The secondary battery according to any one of claims 1 to 6, characterized in that, The first connecting part includes a plurality of electrode connecting parts, which are arranged at intervals along the circumference of the current collecting member; The current collecting component further includes at least one thickness reduction portion, which is disposed on at least one side of the two sides of the first connecting portion along the thickness direction. The thickness reduction portion surrounds the radial outer side of the electrode connecting portion. The thickness reduction portion is a closed ring or includes a plurality of arc-shaped thinning portions arranged at intervals along the circumference of the current collecting component.

8. The secondary battery according to claim 7, characterized in that, At least one arc-shaped thinning portion is provided on the radially outer side of each of the tab connections.

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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