Secondary batteries, battery packs and electronic devices

Abstract

This invention provides a secondary battery, a battery pack, and an electronic device. The secondary battery includes a housing, an electrode assembly, a cover plate, and a current collector. The housing includes a side wall and an opening. The electrode assembly is disposed within the housing, and the cover plate seals the opening. The current collector includes a first connecting portion, a second connecting portion, and a bent section. Along the height direction of the secondary battery, at least a portion of the second connecting portion overlaps between the side wall and the cover plate. The cover plate has an inclined surface opposite to the bent section, which presses against the bent section so that the outer periphery of the first connecting portion abuts against the side wall. This causes metal shavings generated by the radial movement of the second connecting portion and friction with the side wall of the housing to remain between the top of the second connecting portion and the side wall of the housing, preventing them from falling directly into the housing cavity containing the electrode assembly and avoiding any safety risks to the battery.

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] With the development of lithium battery technology, the energy density of rechargeable batteries is becoming increasingly important. Cylindrical batteries, which can achieve high energy density, have become the mainstream form of rechargeable battery. In existing cylindrical batteries, current collectors are typically placed near the opening of the casing. These current collectors are welded to the side wall of the casing and the tabs of the electrode assembly, thus achieving electrical connection between the casing and the electrode assembly.

[0003] During the assembly of the current collector into the casing, the leads of the current collector are interference-fitted with the side wall of the casing. After entering the interior of the cylindrical battery through the opening, the leads of the current collector are then welded to the side wall of the casing. However, during the assembly process, metal shavings are generated between the leads and the side wall of the casing. These shavings remain inside the casing as foreign objects, posing a safety risk to the cylindrical battery. Utility Model Content

[0004] This invention provides a secondary battery, a battery pack, and an electronic device to solve the technical problem that metal shavings generated during the current collector assembly's friction with the sidewall remain inside the casing as foreign objects, posing a safety risk to the secondary battery.

[0005] This invention provides a secondary battery, comprising a housing, an electrode assembly, a cover plate, and a current collector. The housing includes a surrounding sidewall with an opening at one end. The electrode assembly is disposed within the housing, and the cover plate is connected to the housing and seals the opening. The current collector is disposed between the electrode assembly and the cover plate; the current collector includes a first connecting portion, a second connecting portion, and a bent section. Along the radial direction of the secondary battery, the first connecting portion connects to the second connecting portion via the bent section; along the height direction of the secondary battery, the first connecting portion is recessed into the housing through the opening and electrically connected to the electrode assembly. At least a portion of the second connecting portion overlaps between the sidewall and the cover plate and is electrically connected to the housing and / or the cover plate. The cover plate has an inclined surface opposite to the bent section, which presses against the bent section so that the outer periphery of the first connecting portion abuts against the sidewall.

[0006] In one embodiment of the present invention, along the radial direction of the secondary battery, the outer periphery of the sidewall is flush with the outer periphery of the cover plate, and the outer periphery of the second connecting portion does not extend beyond the outer periphery of the sidewall and / or the cover plate.

[0007] In one embodiment of the present invention, along the radial direction of the secondary battery, the outer periphery of the second connecting portion is flush with the outer periphery of the side wall and / or the cover plate.

[0008] In one embodiment of this utility model, the cover plate includes a third connecting portion and a fourth connecting portion, with the second connecting portion disposed between the third connecting portion and the sidewall. Along the height direction of the secondary battery, the fourth connecting portion connects to the outer periphery of the third connecting portion and protrudes relative to the third connecting portion towards the sidewall. Along the radial direction of the secondary battery, the fourth connecting portion covers the outer periphery of the second connecting portion, and the end face of the second connecting portion facing the sidewall is flush with the end face of the fourth connecting portion facing the sidewall.

[0009] In one embodiment of the present invention, the sidewall has a mating surface facing the cover plate, the second connecting part overlaps the mating surface, the thickness of the sidewall is T, and the overlap length of the second connecting part on the mating surface is L, wherein L≤1 / 2T.

[0010] In one embodiment of the present invention, the cover plate includes a fourth connecting portion, and the side wall further includes a thinning portion, which is a groove formed by recessing from the outer periphery of the side wall to the inner periphery of the side wall; the fourth connecting portion is adapted to the thinning portion.

[0011] In one embodiment of the present invention, the thickness of the sidewall along the radial direction of the secondary battery is T, and the length of the thinned portion is D, wherein D≤1 / 2T.

[0012] In one embodiment of the present invention, the height of the thinned portion along the height direction of the secondary battery is H, wherein H > 0.2 mm.

[0013] The second aspect of this utility model also provides a battery pack 10, the battery pack 10 including any of the secondary batteries described above.

[0014] A third aspect of this invention also provides an electronic device comprising the aforementioned battery pack.

[0015] The beneficial effects of this utility model are as follows: This utility model proposes a secondary battery, a battery pack, and an electronic device. In the structure of this secondary battery, at least part of the second connecting portion of the current collector overlaps between the side wall and the cover plate along the height direction of the secondary battery. This allows for axial positioning of the current collector and the cover plate to be pre-assembled onto the opening, facilitating a one-time welding connection between the current collector, the housing, and the cover plate. During the assembly of the cover plate, the inclined surface on the cover plate presses against the bending section, causing the outer periphery of the first connecting portion to abut against the inner wall of the side wall. Metal shavings generated by the radial movement of the second connecting portion and the friction between it and the side wall of the housing remain between the second connecting portion and the top of the side wall of the housing, instead of falling directly into the housing cavity containing the electrode assembly, thus avoiding any safety risks to the battery. Attached Figure Description

[0016] 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.

[0017] In the attached diagram:

[0018] Figure 1 This is a schematic diagram of the structure of a secondary battery provided in one embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the electrode assembly provided in one embodiment of the present invention;

[0020] Figure 3 This is a partial assembly diagram of the shell, cover plate, and current collection component provided in one embodiment of the present invention. Figure 1 ;

[0021] Figure 4 This is a partial assembly diagram of the shell, cover plate, and current collection component provided in one embodiment of the present invention. Figure 2 ;

[0022] Figure 5 This is a partial assembly diagram of the shell, cover plate, and current collection component provided in one embodiment of the present invention. Figure 3 ;

[0023] Figure 6 This is a schematic diagram of the current collection component structure provided in one embodiment of the present utility model;

[0024] Figure 7 This is a schematic diagram of the structure of the electrode assembly provided in one embodiment of the present invention;

[0025] Figure 8This is a schematic diagram of the structure of an electronic device provided in one embodiment of the present invention.

[0026] The attached figures are labeled as follows:

[0027] 1. Electronic device; 10. Battery pack; 101. Housing; 102. Cover; 11. Working part; 100. Secondary battery; 110. Housing; 111. End wall; 112. Side wall; 1121. Mating surface; 1122. Thinning part; 113. Opening; 120. Electrode assembly; 121. First electrode; 1211. Negative electrode current collector; 1212. First coating area; 1213. First empty foil; 12 2. Diaphragm; 123. Second electrode; 1231. Positive current collector; 1232. Second coating area; 1233. Second empty foil; 124. First tab; 125. Second tab; 130. Cover plate; 131. Third connecting part; 132. Fourth connecting part; 133. Inclined surface; 140. Current collector component; 141. First connecting part; 142. Second connecting part; 143. Bending section; 150. Electrode post. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Please see Figures 1 to 8This utility model provides a secondary battery 100, a battery pack 10, and an electronic device 1. By axially overlapping the current collector 140 between the housing 110 and the cover plate 130, it is possible to facilitate one-time forming welding between the current collector 140, the housing 110, and the cover plate 130, ensuring the assembly and fixation of the current collector 140 on the housing 110. At the same time, it can also improve the technical problem in the existing secondary battery 100 where the cover plate 130 and the current collector 140 are pre-installed into the opening 113 of the housing 110, which compresses the inner wall of the opening 113, easily causing metal shavings to fall off and affecting the quality of the battery product.

[0032] Please see Figure 1 The present invention provides a secondary battery 100, which includes a housing 110, an electrode assembly 120, a cover plate 130, and a current collector 140.

[0033] Please see Figure 1 The housing 110 includes 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 circumference of the side wall 112 is not limited; it can be cylindrical or prismatic, or it can 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, surrounding the outer edge of the end wall 111, with a circular opening 113 formed at the end of the side wall 112 facing away from the end wall 111. A receiving cavity is formed within the housing 110 formed by the end wall 111 and the side wall 112 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components.

[0034] Please see Figures 1 to 2 Electrode assembly 120 is housed within housing 110 and is a component in the secondary battery 100 where electrochemical reactions occur. Housing 110 may contain one or more electrode assemblies 120. Electrode assembly 120 includes a wound structure formed by stacking and winding a first electrode 121, a second electrode 123, and a separator 122, wherein 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.

[0035] Please see Figure 2In 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 coating area 1212 coated with active material and an empty foil without active material. In order to distinguish it from the empty foil on the second electrode 123, the empty foil is called the first empty foil 1213. The first empty foil 1213 is located at the end of the first electrode 121. The first empty foil 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 it from 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.

[0036] Please see Figure 2 In this embodiment, 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 coating area 1232 coated with active material and a second empty foil 1233 uncoated with active material. The second empty foil 1233 is located at the end of the second electrode 123. The other end of the second empty foil 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.

[0037] Please see Figure 2 A 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 cylindrical battery 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.

[0038] Further, please refer to Figure 1If 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.

[0039] Please see Figure 1 The electrode post 150 is fixed to the end wall 111 and electrically connected to the electrode assembly 120. Specifically, the end wall 111 is provided with an electrode post hole, and the electrode post 150 is installed through the electrode post hole and insulated from the end wall 111. The end of the electrode 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 electrode 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 electrode post hole corresponds to the shape of the electrode post 150. In this embodiment, the cross-section of the electrode post 150 is circular.

[0040] Please see Figure 1 The cover plate 130 is connected to the housing 110 and seals the opening 113. Specifically, the outer periphery of the cover plate 130 is welded to the side wall 112 of the housing 110 to seal the opening 113 of the housing 110. The structural form of the welded connection between the outer periphery of the cover plate 130 and the side wall 112 of the housing 110 is not limited, as long as it meets the strength and sealing requirements of the welded connection between the housing 110 and the cover plate 130. For example, the outer periphery of the cover plate 130 and the side wall 112 are mated to form a weld seam around the opening 113 in the circumferential direction. When the cover plate 130 and the side wall 112 are sealed by welding, the laser is focused at the area where the weld seam is located to form a weld pool. The mating side wall 112 and the outer periphery of the cover plate 130 are welded together under the action of the thermal field of the weld pool to close the weld seam, thereby achieving the sealing weld between the outer periphery of the cover plate 130 and the side wall 112. The weld seam is located at the welding position between the cover plate 130 and the side wall 112, and the formation direction of the weld seam is related to the relative mating direction of the cover plate 130 and the side wall 112. For example, it is an annular weld seam formed by the outer periphery of the cover plate 130 and the outer wall of the side wall 112 along the circumferential direction of the opening 113. Or it is an annular weld seam formed by the outer periphery of the cover plate 130, the outer periphery of the flow collecting member 140, and the outer wall of the side wall 112 along the circumferential direction of the opening 113.

[0041] Please see Figure 3 and Figure 6A current collector 140 is disposed between the electrode assembly 120 and the cover plate 130, and is used to connect the first tab 124 and the cover plate 130. During the assembly of the secondary battery 100, the current collector 140 is placed between the tab and the cover plate 130, and then the three are welded together to achieve battery sealing and the formation of a current circuit. The current collector 140 includes a first connecting portion 141, a second connecting portion 142, and a bent section 143. Along the radial direction of the secondary battery, the first connecting portion 141 is recessed into the housing 110 through the opening 113 and is electrically connected to the electrode assembly 120. That is, the first connecting portion 141 is welded to the first tab 124 to achieve electrical connection between the current collector 140 and the first tab 124. Along the radial direction of the secondary battery, the first connecting portion 141 and the second connecting portion 142 are connected by a bending section 143. The first connecting portion 141, the second connecting portion 142, and the bending section 143 can be integrally stamped or integrally injection molded. Along the height direction of the secondary battery 100, at least a portion of the second connecting portion 142 overlaps between the side wall 112 and the cover plate 130, and is electrically connected to the housing 110 and / or the cover plate 130. Specifically, after the first connecting portion 141 is recessed into the housing 110 through the opening 113, the second connecting portion 142 overlaps at the end of the side wall 112, which facilitates the support and fixation of the current collector 140 on the housing 110, and creates a contact area between the current collector 140, the cover plate 130, and the housing 110, thereby facilitating a one-time welding connection between the current collector 140, the housing 110, and the cover plate 130, and realizing the electrical connection between the second connecting portion 142 and the housing 110 and / or the cover plate 130.

[0042] Please see Figure 3The surface of the cover plate 130 facing the electrode assembly 120 has an inclined surface 133 opposite to the bent section 143. The inclined surface 133 presses against the bent section 143 so that the outer periphery of the first connecting portion 141 abuts against the side wall 112. Specifically, when the cover plate 130 is assembled from top to bottom along the height direction of the secondary battery 100 to the opening 113 of the housing 110, the inclined surface 133 presses against the bent section 143, applying a radially outward compressive force to the bent section 143 so that the outer periphery of the first connecting portion 141 abuts against the inner wall of the side wall 112. At the same time, along the radial direction of the secondary battery 100, the surface of the second connecting portion 142 facing the side wall 112 slides on the end face of the side wall 112, that is, the second connecting portion 142 expands radially outward from the inner wall of the side wall 112 towards the outer wall. After the cover plate 130 is installed, the outer periphery of the first connecting portion 141 abuts against the inner wall of the side wall 112, preventing the second connecting portion 142 from excessively expanding radially outward. The second connecting portion 142 is pressed between the cover plate 130 and the side wall 112, and the second connecting portion 142 forms a mating surface with both the cover plate 130 and the side wall 112. During the radial expansion process, metal shavings generated by the friction between the second connecting portion 142 and the end face of the side wall 112 remain between the mating surfaces of the second connecting portion 142 and the side wall 112, and do not fall directly into the receiving cavity of the housing 110 that houses the electrode assembly 120, thus avoiding any safety risks to the battery.

[0043] Please see Figure 3 and Figure 4In one embodiment of the present invention, the outer periphery of the sidewall 112 is flush with the outer periphery of the cover plate 130 along the radial direction of the secondary battery 100. Furthermore, the outer periphery of the second connecting portion 142 does not extend beyond the outer periphery of the sidewall 112 and / or the cover plate 130 along the radial direction of the secondary battery 100. Specifically, in one embodiment, the outer periphery of the second connecting portion 142 can be flush with the outer periphery of the side wall 112 and the cover plate 130. During the integral welding of the current collecting member 140, the cover plate 130 and the side wall 112, the weld seam of the three is located on the same cylindrical surface. One circumferential weld along the circumference of the shell 110 can complete the welding fixation in one go, without the need for segmented welding. At the same time, since the outer periphery of the side wall 112 and the cover plate 130 is flush with the outer periphery of the current collecting member 140, there is no need to avoid any protruding structures during the side welding process. The welding equipment can be injected vertically along the circumference of the shell 110. During the welding process, the exhaust path of the weld pool is smooth, and the porosity and spatter inside the weld seam are significantly reduced, improving the welding quality and the sealing performance after welding. In other embodiments, along the radial direction of the secondary battery 100, the outer periphery of the second connecting portion 142 is at a certain distance from the outer periphery of the side wall 112 or the cover plate 130. The outer periphery of the side wall 112 is flush with the outer periphery of the cover plate 130, and there is a mating surface at the junction. During the process of integrally welding the current collector 140, cover plate 130, and side wall 112 to form an electrical connection, the laser welding power can be increased in the common contact area of ​​the current collector 140, cover plate 130, and side wall 112. Spot welding or penetration welding can be performed at multiple points along the circumference of the housing 110, so that the current collector 140, cover plate 130, and housing 110 form a partially integral welded connection area. Then, circumferential welding is performed at the mating surface of cover plate 130 and side wall 112 to achieve a sealed connection between cover plate 130 and side wall 112.

[0044] Please see Figure 3 In one embodiment of this utility model, along the radial direction of the secondary battery 100, the outer periphery of the second connecting portion 142 is flush with the outer periphery of the side wall 112 and / or the cover plate 130. Specifically, along the height direction of the secondary battery 100, the outer peripheries of the side wall 112, the second connecting portion 142, and the cover plate 130 are coplanar, forming a continuous cylindrical surface without any radial protrusions. After the outer peripheries of the three are flush, during the welding process, the welding energy can be applied continuously along the same cylindrical surface at once, and the laser or electron beam can be incident in a direction perpendicular to the cylindrical surface, without step shadows, with uniform energy distribution. The welding process results in high consistency of weld penetration and weld width, avoiding welding defects such as porosity and spatter, and improving the welding qualification rate.

[0045] Please see Figure 4In one embodiment of this utility model, the cover plate 130 adopts an inverted vertical edge structure, and the cover plate 130 includes a third connecting portion 131 and a fourth connecting portion 132. After the cover plate 130 is assembled at the opening 113, the second connecting portion 142 is sandwiched between the third connecting portion 131 and the side wall 112. Along the height direction of the secondary battery, the fourth connecting portion 132 is integrally connected to the outer periphery of the third connecting portion 131, and protrudes relative to the third connecting portion 131 towards the side wall 112, forming an annular flange facing the opening 113 of the housing 110. Along the radial direction of the secondary battery 100, the inner periphery of the fourth connecting portion 132 covers the outer periphery of the second connecting portion 142. Furthermore, along the radial direction of the secondary battery 100, the end face of the second connecting portion 142 facing the side wall 112 is flush with the end face of the fourth connecting portion 132 facing the side wall 112. That is, the end faces of the second connecting portion 142 and the fourth connecting portion 132 facing the side wall 112 fit together to form a mating surface, reducing the contact resistance between the current collector 140 and the housing 110 and the cover plate 130, and ensuring the stability of the electrical connection between the current collector 140, the housing 110, and the cover plate 130. At the same time, the snap-fit ​​structure between the fourth connecting portion 132 and the current collector 140 facilitates the assembly and positioning of the cover plate 130.

[0046] Please see Figure 4 In one embodiment of this utility model, the sidewall 112 has a mating surface 1121 facing the cover plate 130, and the second connecting part 142 overlaps the mating surface 1121. The thickness of the sidewall 112 is T, and the overlap length of the second connecting part 142 on the mating surface 1121 is L, wherein L≤1 / 2T. The overlap length of the second connecting part 142 on the mating surface 1121 does not exceed half the thickness of the sidewall 112, which ensures the overlap fixation of the current collecting member 140 during assembly. At the same time, during the welding and sealing process between the sidewall 112 and the fourth connecting part 132, the heat conduction of welding heat to the interior of the shell 110 is significantly reduced, improving the welding quality between the sidewall 112 and the cover plate 130.

[0047] Please see Figure 5In one embodiment of this utility model, the cover plate 130 includes a fourth connecting portion 132, and the side wall 112 includes a thinning portion 1122. The thinning portion 1122 is an annular groove formed by the outer periphery of the side wall 112 recessed towards the inner periphery of the side wall 112. The fourth connecting portion 132 is adapted to the thinning portion 1122. Specifically, the fourth connecting portion 132 of the cover plate 130 has an annular flange structure, and its inner wall is consistent with the contour of the groove. During assembly, the fourth connecting portion 132 is inserted into the thinning portion 1122 along the height direction of the secondary battery, so that the outer periphery of the cover plate 130 and the outer periphery of the side wall 112 are restored to the same cylindrical surface, and a guiding function is provided, thereby simplifying the assembly process of the cover plate 130 and the side wall 112. At the same time, the inner wall of the side wall 112 has a complete structure without protrusions or depressions, which facilitates the assembly of the electrode assembly 120 into the shell. Furthermore, during the assembly of the cover plate 130 and the housing 110, metal shavings generated by friction between the inner periphery of the fourth connecting part 132 and the side wall 112 are prevented from falling into the housing 110.

[0048] Please see Figure 4 In one embodiment of this utility model, along the radial direction of the secondary battery 100, the thickness of the sidewall 112 is T, and the length of the thinned portion 1122 is D, where D≤1 / 2T. The thinning length of the thinned portion 1122 does not exceed half the thickness of the sidewall 112, ensuring that the shell 110 still has sufficient circumferential stiffness at the opening 113 end, and preventing the sidewall 112 from being welded through to the fourth connecting portion 132 during welding.

[0049] Please see Figure 5 In one embodiment of this utility model, the height of the thinned portion 1122 along the height direction of the secondary battery 100 is H, where H > 0.2 mm. During the welding process between the shell 110 and the cover plate 130, the weld pool has sufficient dimensions in the height direction of the secondary battery 100 to ensure welding quality.

[0050] Please see Figure 7 The second aspect of this 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 a plurality of secondary batteries 100. The plurality of secondary batteries 100 are placed in the housing 101 and are connected in series or in parallel, or a combination of series and parallel connections. The cover 102 seals the housing 101 to protect the plurality of 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.

[0051] Please see Figure 8This utility model also provides an electronic device, 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, and spacecraft, 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 embodiment does not impose any special limitations on the aforementioned electronic device 1.

[0052] In the secondary battery, battery pack, and electronic device proposed in this utility model, the structure of the secondary battery includes at least a portion of the second connecting part of the current collector component overlapping between the side wall and the cover plate along the height direction of the secondary battery. This allows for axial positioning and pre-assembly of the current collector component and the cover plate onto the opening, facilitating subsequent one-time welding connection between the current collector component, the housing, and the cover plate. During the cover plate assembly process, the inclined surface on the cover plate presses against the bending section, causing the outer periphery of the first connecting part to abut against the inner wall of the side wall. Metal shavings generated by the radial movement of the second connecting part and its friction with the side wall of the housing remain between the second connecting part and the top of the side wall of the housing, instead of falling directly into the housing cavity containing the electrode assembly, thus avoiding safety risks to the battery. This solves the technical problem of metal shavings generated during the current collector component's insertion into the housing becoming foreign objects inside the housing, posing a safety risk to the secondary battery.

[0053] 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, the housing including surrounding sidewalls, one end of which is formed with an opening; Electrode assembly, disposed within the housing; A cover plate, connected to the housing, and sealing the opening; A current collector is disposed between the electrode assembly and the cover plate; the current collector includes a first connecting portion, a second connecting portion, and a bent section. Along the radial direction of the secondary battery, the first connecting portion is connected to the second connecting portion through the bent section; along the height direction of the secondary battery, the first connecting portion is recessed into the housing through the opening and is electrically connected to the electrode assembly; at least a portion of the second connecting portion overlaps between the side wall and the cover plate and is electrically connected to the housing and / or the cover plate. The cover plate is provided with an inclined surface opposite to the bent section; the inclined surface presses against the bent section so that the outer periphery of the first connecting part abuts against the side wall.

2. The secondary battery according to claim 1, characterized in that, Along the radial direction of the secondary battery, the outer periphery of the sidewall is flush with the outer periphery of the cover plate, and the outer periphery of the second connecting portion does not extend beyond the outer periphery of the sidewall and / or the cover plate.

3. The secondary battery according to claim 2, characterized in that, Along the radial direction of the secondary battery, the outer periphery of the second connection portion is flush with the outer periphery of the side wall and / or the cover plate.

4. The secondary battery according to claim 2, characterized in that, The cover plate includes a third connecting part and a fourth connecting part, and the second connecting part is disposed between the third connecting part and the side wall; Along the height direction of the secondary battery, the fourth connecting portion connects to the outer periphery of the third connecting portion and protrudes relative to the third connecting portion toward the sidewall. Along the radial direction of the secondary battery, the fourth connecting portion covers the outer periphery of the second connecting portion, and the end face of the second connecting portion facing the sidewall is flush with the end face of the fourth connecting portion facing the sidewall.

5. The secondary battery according to claim 4, characterized in that, The sidewall has a mating surface facing the cover plate, the second connecting part overlaps the mating surface, the thickness of the sidewall is T, and the overlap length of the second connecting part on the mating surface is L, wherein L≤1 / 2T.

6. The secondary battery according to claim 2, characterized in that, The cover plate includes a fourth connecting portion, and the side wall also includes a thinning portion, which is a groove formed by recessing from the outer periphery of the side wall to the inner periphery of the side wall; the fourth connecting portion is adapted to the thinning portion.

7. The secondary battery according to claim 6, characterized in that, Along the radial direction of the secondary battery, the thickness of the sidewall is T, and the length of the thinned portion is D, where D≤1 / 2T.

8. The secondary battery according to claim 6, characterized in that, Along the height direction of the secondary battery, the height of the thinned portion is H, where H > 0.2 mm.

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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