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 shell, an electrode assembly, a current collecting component and a sealing plate, the shell comprises a side wall and a cover plate assembly, and the side wall comprises an opening; the cover plate assembly seals the opening; the cover plate assembly comprises a first cover plate and a second cover plate, and the first cover plate covers the opening and is in sealed connection with the side wall; the first cover plate comprises a first through hole; the second cover plate at least partially shields the first through hole and is welded with the first cover plate; the electrode assembly is arranged in the shell and is provided with a roll core through hole; the current collecting component is arranged on the side, facing the cover plate component, of the electrode component, and the current collecting component is electrically connected with the electrode component and the shell; the sealing plate is arranged on one side of the second cover plate away from the electrode assembly; liquid injection holes are formed in the first cover plate and / or the second cover plate, and the projections of the liquid injection holes are located on the periphery of the roll core through hole; and the sealing plate seals the liquid injection hole. According to the utility model, the technical problem that the position of the roll core through hole of the electrode assembly is easy to collapse in the liquid injection process can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a secondary battery, a battery pack and an electronic device. Background Art

[0002] In the prior art, secondary batteries usually adopt a central injection method, that is, the injection hole is set at the position of the winding core through-hole of the electrode assembly. With this injection method, when injecting liquid into the interior of the shell, the electrolyte with a high flow rate will directly rush into the interior of the winding core through-hole, which can easily cause local collapse at the location of the winding core through-hole, affecting the integrity of the electrode interface, and thus reducing the charge and discharge performance and cycle stability of the secondary battery. At the same time, during the injection process, the electrolyte needs to penetrate into the diaphragm first and then penetrate through the diaphragm into the electrode during the flow inside the secondary battery, which will also limit the infiltration speed of the electrode assembly. Utility Model Content

[0003] The utility model provides a secondary battery, a battery pack and an electronic device, which are used to improve the technical problem that the position of the winding core through hole of the electrode assembly is prone to collapse during the liquid injection process.

[0004] To achieve the above-mentioned objectives and other related objectives, the utility model provides a secondary battery, comprising: a shell, an electrode assembly, a current collecting component and a sealing plate; the shell comprises a side wall and a cover plate assembly, the side wall comprises an opening at one end along the axial direction of the secondary battery; the cover plate assembly seals the opening; the cover plate assembly comprises: a first cover plate and a second cover plate, the first cover plate covers the opening and is sealed with the side wall; the first cover plate comprises a first through hole; the second cover plate at least partially covers the first through hole; the second cover plate is welded to the first cover plate; the electrode assembly is sealed and installed in the shell, and the electrode assembly has a winding core through hole; the current collecting component is arranged on the side of the electrode assembly facing the cover plate assembly, and the current collecting component is electrically connected to the electrode assembly and the shell respectively; the sealing plate is arranged on the side of the second cover plate away from the electrode assembly; wherein the first cover plate and / or the second cover plate are provided with an injection hole, and the projection of the injection hole is located on the outer periphery of the winding core through hole along the axial direction of the secondary battery; the sealing plate seals the injection hole.

[0005] In an example of the secondary battery of the present invention, the liquid injection hole includes a second through hole provided in the second cover plate, at least a portion of the second through hole is exposed to the first through hole, and at least another portion is connected to the end surface of the electrode assembly on the opening side.

[0006] In an example of a secondary battery of the present invention, along the axial direction of the secondary battery, the second cover plate is arranged between the first cover plate and the current collecting member, and the outer edge of the second cover plate abuts against the outer peripheral edge of the first through hole; the surface of the first cover plate facing the electrode assembly at least partially blocks the second through hole.

[0007] In an example of the secondary battery of the present invention, the second through hole extends along the radial direction of the secondary battery and passes through the outer edge of the second cover plate.

[0008] In an example of a secondary battery of the present invention, along the axial direction of the secondary battery, the second cover plate is arranged between the first cover plate and the current collecting member, and the outer edge of the second cover plate abuts the outer peripheral edge of the first through hole; the injection hole includes a through groove arranged on the first cover plate and / or the second cover plate, one end of the through groove is connected to the first through hole, and the other end extends along the radial direction of the secondary battery and is connected to the end face of the electrode assembly located on the opening side.

[0009] In an example of the secondary battery of the present invention, the through groove includes a second groove provided on the second cover plate, the second groove is located on a side of the second cover plate facing the first cover plate, and at least a portion of the second groove is exposed to the first through hole.

[0010] In an example of the secondary battery of the present invention, the through slot includes a first groove provided on the first cover plate, the first groove is located on a side of the first cover plate facing the second cover plate, and the first groove is communicated with the first through hole.

[0011] In an example of the secondary battery of the present invention, the current collecting component includes a current collecting body and a cover plate welding portion, the cover plate welding portion is welded to the second cover plate to form a first weld mark, the first weld mark is spaced apart from the injection hole, and the surface of the first weld mark is coated with sealant.

[0012] In an example of the secondary battery of the present invention, the sealing plate covers the first weld mark.

[0013] In an example of a secondary battery of the present invention, the thickness of the cover plate welding part is greater than the thickness of the current collecting body, and the cover plate welding part protrudes toward the second cover plate side relative to the current collecting body; the central area of the cover plate welding part includes a central hole connected to the core through hole, and the edge area of the cover plate welding part includes a third groove, and the two ends of the third groove are respectively connected to the liquid injection hole and the central hole.

[0014] The utility model also provides a battery pack, which includes the secondary battery in any one of the above examples.

[0015] The present invention further provides an electronic device, which includes the battery pack in the above example.

[0016] In the secondary battery of the present invention, since the projection of the injection hole is located on the periphery of the winding core through-hole along the axial direction of the secondary battery, the injection hole and the winding core through-hole can be offset in the radial direction. With this arrangement, when electrolyte is injected through the injection hole, the impact force generated by the high-speed electrolyte is absorbed by the current collecting member or the end face of the electrode assembly at the position directly opposite the injection hole. This can mitigate the impact of the liquid flow on the winding core through-hole, correspondingly reducing the probability of collapse at the winding core through-hole position, improving the integrity of the electrode interface at this location, and thus improving the charge and discharge performance and cycle stability of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a cross-sectional view of the overall structure of an embodiment of a secondary battery of the present utility model;

[0019] Figure 2 for Figure 1 A local enlarged view of the middle area A;

[0020] Figure 3 A partial cross-sectional view of a second cover plate with a second through hole in an embodiment of a secondary battery according to the present invention;

[0021] Figure 4 for Figure 3 A schematic structural diagram of the second cover plate in the embodiment;

[0022] Figure 5 A partial cross-sectional view of another embodiment of the secondary battery of the present invention, in which a second through hole is provided on the second cover;

[0023] Figure 6 for Figure 5 A schematic structural diagram of the second cover plate in the embodiment;

[0024] Figure 7 This is a schematic diagram of the liquid injection hole at the first through hole after removing the sealing plate in one embodiment of the secondary battery of the present invention;

[0025] Figure 8 A partial cross-sectional view of a secondary battery according to an embodiment of the present invention in which a through groove is provided on the second cover plate;

[0026] Figure 9 A three-dimensional partial cross-sectional view of a secondary battery according to an embodiment of the present invention in which a through groove is provided on the second cover plate;

[0027] Figure 10 This is a structural diagram of a second cover plate provided with a first groove in an embodiment of a secondary battery of the present invention;

[0028] Figure 11 This is a structural schematic diagram of another embodiment of the secondary battery of the present invention in which the second cover plate is provided with a first groove;

[0029] Figure 12 A partial cross-sectional view of a second groove provided on the first cover plate in an embodiment of a secondary battery of the present invention;

[0030] Figure 13 This is a schematic diagram of the three-dimensional structure of the first cover plate in one embodiment of the secondary battery of the present invention in one angle direction;

[0031] Figure 14 This is a schematic diagram of the three-dimensional structure of the first cover plate in another angle direction in an embodiment of the secondary battery of the present invention;

[0032] Figure 15 This is a schematic structural diagram of a secondary battery according to an embodiment of the present invention, in which the through groove is located at the first through hole after the sealing plate is removed;

[0033] Figure 16 This is a schematic diagram of the overall structure of the current collecting component in one embodiment of the secondary battery of the present utility model;

[0034] Figure 17 This is a schematic diagram of the overall structure of a secondary battery in an embodiment of the present invention, in which a third groove is provided on the current collecting member;

[0035] Figure 18 A partial cross-sectional view of a current collecting member provided with a third groove in an embodiment of a secondary battery of the present invention;

[0036] Figure 19 This is a structural diagram of a secondary battery in accordance with an embodiment of the present invention in which a current collecting component is not provided with a cover plate welding portion;

[0037] Figure 20 This is a partial cross-sectional view of a secondary battery according to an embodiment of the present invention, in which a current collecting component is not provided with a cover plate welding portion;

[0038] Figure 21 This is a schematic diagram of the distribution of the first weld print on the second cover plate in one embodiment of the secondary battery of the present utility model;

[0039] Figure 22 This is a schematic diagram of the overall structure of an embodiment of a battery pack of the present utility model;

[0040] Figure 23 This is a structural schematic diagram of the battery pack of the utility model installed on a vehicle.

[0041] Component number description

[0042] 100, secondary battery; 110, housing; 111, side wall; 112, opening; 113, end wall; 120, electrode assembly; 121, winding core through hole; 122, first electrode tab; 123, second electrode tab; 124, gas storage space; 130, current collecting member; 131, current collecting body; 132, cover plate welding portion; 1321, center hole; 1322, third groove; 140, cover plate assembly; 141, first cover plate; 1411, first through hole; 1412, first protrusion; 14 13. Cover portion; 1414. Second protrusion; 142. Second cover plate; 1421. First weld mark; 150. Electrode terminal; 160. Sealing plate; 170. Liquid injection hole; 171. Second through hole; 1711. Through opening; 172. Through groove; 1721. Second groove; 17211. Groove opening; 1722. First groove; 200. Battery pack; 210. Case; 211. First case portion; 212. Second case portion; 300. Electronic device; 310. Working portion. DETAILED DESCRIPTION

[0043] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation methods. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following examples and the features in the examples can be combined with each other unless there is a conflict. It should also be understood that the terms used in the examples of the present invention are for the purpose of describing specific implementation methods, not for the purpose of limiting the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0044] When numerical ranges are given in the examples, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any value between the endpoints may be used. Unless otherwise defined, all technical and scientific terms used in this utility model are consistent with the prior art as understood by those skilled in the art and the description of this utility model. Any prior art methods, equipment, and materials similar or equivalent to those described in the examples of this utility model may also be used to implement this utility model.

[0045] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0046] See also Figures 1 to 23 The present invention provides a secondary battery 100, a battery pack 200, and an electronic device 300. In the secondary battery 100, the projection of the injection hole 170 is located on the periphery of the winding core through-hole 121. This allows the injection hole 170 to be radially offset from the winding core through-hole 121. This prevents the electrolyte from directly entering the winding core through-hole 121 during the injection process, thereby mitigating the impact of the electrolyte flow on the winding core through-hole 121 and reducing the probability of collapse at the winding core through-hole 121. This improves the charge-discharge performance and cycle stability of the secondary battery 100.

[0047] See also Figure 1 and Figure 2 The secondary battery 100 includes a case 110 , an electrode assembly 120 , a current collecting member 130 , and a sealing plate 160 .

[0048] An installation cavity is formed in the shell 110 for installing the electrode assembly 120, the electrolyte (not shown) and other components. The installation cavity can be an opening 112 at one end or an opening 112 at both ends. Specifically, the size of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as a diameter of 46 mm, a height of 80 mm, 95 mm, 120 mm and other specifications. The shell 110 can be in a variety of shapes, such as cylindrical, prismatic, etc. The material of the shell 110 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 110 from rusting during long-term use, a layer of rust-proof material, such as metal nickel, etc., can also be plated on the surface of the shell 110.

[0049] See also Figure 1 In one example of the secondary battery 100 of the present invention, the housing 110 is a cylindrical structure, comprising an end wall 113, a side wall 111 surrounding the end wall 113, and a cover assembly 140. Along the height direction of the housing 110, one end of the side wall 111 is fixedly connected to the end wall 113, forming a closed end. The other end of the side wall 111 is provided with an opening 112. The cover assembly 140 is disposed at the opening 112 and seals the opening 112.

[0050] like Figure 1 and Figure 2As shown, the electrode assembly 120 is housed in the shell 110. The electrode assembly 120 is a component in the secondary battery 100 where electrochemical reactions occur. The electrode assembly 120 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. Preferably, in this embodiment, the electrode assembly 120 is formed by winding the positive electrode sheet, the negative electrode sheet and the separator, and a winding core through hole 121 is formed in the central area of the electrode assembly 120. The positive electrode sheet includes a positive current collector and a positive active material layer, and the positive active material layer is coated on the surface of the positive current collector; the positive current collector includes a positive coating area and a positive electrode tab connected to the positive coating area, the positive coating area is coated with the positive active material layer, and the positive electrode tab is not coated with the positive active material layer. The negative electrode sheet includes a negative current collector and a negative active material layer, which is coated on the surface of the current collector. The negative current collector includes a negative coating region and a negative tab connected to the negative coating region. The negative coating region is coated with the negative active material layer, while the negative tab is uncoated. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material layer includes a positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative current collector can be made of copper, and the negative active material layer includes a negative active material, which can be carbon or silicon. The separator can be primarily made of PP or PE. To protect and insulate the electrode assembly 120, an insulating film can be applied to the outside of the electrode assembly 120. The insulating film can be made of PP, PE, PET, PVC, or other polymer materials.

[0051] See also Figure 1 In one example of the secondary battery 100 of the present invention, the electrode assembly 120 is sealed within the housing 110. A first electrode tab 122 and a second electrode tab 123 are respectively provided at opposite ends of the lengthwise direction of the electrode assembly 120. The first electrode tab 122 and the second electrode tab 123 have opposite polarities. The first electrode tab 122 faces the opening 112 of the housing 110 and is the negative electrode tab. It should be noted that in other embodiments, the first electrode tab 122 may be the positive electrode tab, and the second electrode tab 123 may be the negative electrode tab.

[0052] See also Figure 1In one example of the secondary battery 100 of the present invention, a terminal mounting hole is formed through the end wall 113 of the housing 110. The electrode terminal 150 is installed in a sealed and insulated manner within the terminal mounting hole. The mounting method of the electrode terminal 150 on the end wall 113 is not limited as long as the seal and insulation between the electrode terminal 150 and the end wall 113 are achieved. The electrode assembly 120 has a second electrode tab 123 on the side facing the end wall 113. One end of the electrode terminal 150 can be directly welded to the second electrode tab 123 or conductively connected to the second electrode tab 123 via a current collecting member, without specific limitations.

[0053] See also Figure 2 In one example of the secondary battery 100 of the present invention, the current collecting member 130 is disposed within the housing 110 and is located on the side of the electrode assembly 120 facing the cap plate assembly 140. The current collecting member 130 is welded to the first electrode tab 122 and the housing 110 to achieve electrical connection. The current collecting member 130 can be welded to the cap plate assembly 140, to the sidewall 111, or to both the cap plate assembly 140 and the sidewall 111. The specific location and area of the welding between the current collecting member 130 and the first electrode tab 122 are not limited, as long as a stable electrical connection between the current collecting member 130 and the first electrode tab 122 is achieved.

[0054] See also Figure 2 and Figure 3 , the cover plate assembly 140 includes a first cover plate 141 and a second cover plate 142. The first cover plate 141 covers the opening 112, and the outer edge of the first cover plate 141 is sealed to the side wall 111 of the shell 110. There can be various sealing methods, such as welding connection sealing, mechanical crimping sealing, etc. The first cover plate 141 includes a first through hole 1411, and the first through hole 1411 can be located in the central area of the first cover plate 141, or it can be offset from the central area. The shape of the first through hole 1411 can also be various, such as a square hole, a round hole or other special-shaped holes. Preferably, in order to facilitate the processing and positioning of the first through hole 1411 on the first cover plate 141, in this embodiment, the first through hole 1411 is a round hole structure, and the first through hole 1411 is coaxially arranged with the first cover plate 141.

[0055] Please continue reading Figure 2 and Figure 3The second cover plate 142 is disposed on the side of the current collecting member 130 facing away from the electrode assembly 120, and the second cover plate 142 at least partially blocks the first through hole 1411. The outer edge of the second cover plate 142 is welded to the first cover plate 141. Along the axial direction of the secondary battery 100, the second cover plate 142 can be located on the side of the first cover plate 141 facing away from the electrode assembly 120, or on the side of the first cover plate 141 facing the electrode assembly 120, as long as it can partially block the first through hole 1411. The second cover plate 142 can be in the shape of a disk that matches the first through hole 1411, or it can be in other shapes that can block the first through hole 1411, such as a rectangular plate, a polygonal plate, etc.

[0056] It should be noted that the current collecting member 130 may be welded to the first cover plate 141 or to the second cover plate 142 , as long as electrical connection between the current collecting member 130 and the first cover plate 141 is achieved.

[0057] See also Figure 2 In one embodiment, the first cover plate 141 is provided with a liquid injection hole 170. The shape of the liquid injection hole 170 is not limited, for example, it can be a circular hole, an elongated hole or a through groove, etc. In other embodiments, the liquid injection hole 170 can be provided on the second cover plate 142. In some other embodiments, both the first cover plate 141 and the second cover plate 142 can be provided with a liquid injection hole 170. As long as the liquid injection requirements of the secondary battery 100 can be met, the specific setting position of the liquid injection hole 170 is not limited. The sealing plate 160 is provided on the side of the second cover plate 142 away from the electrode assembly 120, and the sealing plate 160 seals the liquid injection hole 170. The sealing plate 160 can be sealed and connected to the first cover plate 141, or it can be sealed and connected to the second cover plate 142, as long as it is ensured that the sealing plate 160 can seal the liquid injection hole 170.

[0058] See also Figure 2, along the axial direction of the secondary battery 100, the projection of the injection hole 170 is located on the outer periphery of the core through hole 121, that is, the projection of the injection hole 170 does not overlap with the projection of the core through hole 121. In this way, the injection hole 170 and the core through hole 121 can be offset in the radial direction of the secondary battery 100. When the electrolyte is injected through the injection hole 170, the liquid flow impact force generated by the electrolyte will be absorbed by the collecting component 130 or the end face of the electrode assembly 120 at the position directly opposite the injection hole 170, thereby slowing down or avoiding the liquid flow impact at the position of the core through hole 121. This can reduce the probability of local collapse at the position of the core through hole 121, improve the integrity of the electrode interface at this position, and further improve the charge and discharge performance and cycle stability of the secondary battery 100. At the same time, since the injection hole 170 can directly enter the end face of the electrode assembly 120 below or enter the end face of the electrode assembly 120 after passing through the collecting component 130, compared with the method in which the electrolyte directly enters the interior of the electrode assembly 120 from the winding core through hole 121, this method can make the electrolyte penetrate into the interior of the electrode assembly 120 from the end face tab stacking layer of the electrode assembly 120, thereby increasing the infiltration speed of the electrolyte in the interior of the electrode assembly 120, and at the same time, it can also increase the exhaust speed inside the shell 110 during the formation process, thereby improving the production efficiency of the secondary battery 100.

[0059] See also Figures 2 to 4 In an example of the secondary battery 100 of the present invention, the liquid injection hole 170 includes a second through hole 171 provided on the second cover plate 142, at least a portion of the second through hole 171 is exposed to the first through hole 1411, and at least another portion is connected to the end face of the electrode assembly 120 on the side of the opening 112. The second through hole 171 can be completely exposed to the first through hole 1411, or partially exposed to the first through hole 1411. The second through hole 171 is connected to the end face of the electrode assembly 120, which means that the second through hole 171 is connected to the end face of the electrode assembly 120 on the side of the opening 112. The second through hole 171 can be directly connected to the end face of the electrode assembly 120 below, or it can be indirectly connected to the end face of the electrode assembly 120 through the hollow area provided on the current collecting member 130. The second through hole 171 can be any shape, such as an elongated hole, a circular hole, a rectangular hole, etc. By setting the second through hole 171, the injection hole 170 can be connected with the end face of the electrode assembly 120 in the vertical direction, shortening the length of the electrolyte flow path, and thereby increasing the flow rate of the electrolyte entering the end face of the electrode assembly 120, which is beneficial to increasing the infiltration speed of the electrolyte inside the electrode assembly 120.

[0060] Specifically, see Figure 3 and Figure 4In this embodiment, the second through hole 171 is an elongated hole. Along its length, one end of the elongated hole is exposed within the first through hole 1411, and the other end of the elongated hole extends radially outward from the secondary battery 100. This arrangement allows the elongated hole to extend longer in the radial direction of the electrode assembly 120, given the same area. This improves the uniformity of electrolyte infiltration along the radial direction of the end surface of the electrode assembly 120, thereby achieving better electrolyte injection results.

[0061] It should be noted that the number of second through holes 171 can be one or more. Preferably, in one embodiment, in order to improve the uniformity of liquid injection inside the electrode assembly 120, multiple second through holes 171 are provided, and the multiple second through holes 171 are arranged in an array along the axis of the electrode assembly 120. In this way, a relatively uniform liquid injection effect can be achieved in the circumferential direction of the electrode assembly 120.

[0062] See also Figure 2 and Figure 3 In one example of the secondary battery 100 of the present invention, the second cover plate 142 is disposed between the first cover plate 141 and the current collecting member 130 along the axial direction of the secondary battery 100. The outer edge of the second cover plate 142 extends below the outer periphery of the first through hole 1411 and abuts against the surface of the outer periphery of the first through hole 1411 facing the electrode assembly 120. The surface of the first cover plate 141 facing the electrode assembly 120 at least partially blocks the second through hole 171. With this arrangement, when electrolyte is injected through the second through hole 171, in the radial direction of the secondary battery 100, the electrolyte can flow through the second through hole 171 into the end surface area of the electrode assembly 120 below the abutment position of the second cover plate 142 and the first cover plate 141, thereby achieving electrolyte injection into the interior of the electrode assembly 120 and improving the uniformity of electrolyte injection in the radial direction of the electrode assembly 120.

[0063] In order to further increase the injection speed inside the electrode assembly 120, preferably, refer to Figure 5 and Figure 6 In one example of the secondary battery 100 of the present invention, the second through hole 171 extends in the radial direction of the secondary battery 100 and penetrates the outer edge of the second cover plate 142. This configuration forms a through opening 1711 on the side of the second through hole 171 away from the first through hole 1411. The provision of the through opening 1711 can reduce the resistance of the electrolyte entering the end face of the electrode assembly 120, thereby further improving the injection speed of the electrolyte into the electrode assembly 120.

[0064] Compared to Figure 3 The difference between the embodiments shown is that in an example of the secondary battery 100 of the present invention, please refer to Figure 12 and Figure 13The injection hole 170 includes a through groove 172 provided on the first cover plate 141. One end of the through groove 172 is connected to the first through hole 1411, and the other end extends along the radial direction of the secondary battery 100 and is connected to the end surface of the electrode assembly 120 located on the side of the opening 112. The cross-sectional shape of the through groove 172 is not limited, for example, it can be a circular cross-section, a rectangular cross-section, etc. In other embodiments, the through groove 172 can be provided on the second cover plate 142, such as Figure 9 and Figure 10 In other embodiments, the through slot 172 may be partially provided on the first cover plate 141 and partially provided on the second cover plate 142, as shown in FIG. Figure 15 By providing the through slots 172 , when electrolyte is injected through the injection hole 170 , the electrolyte is transported through the through slots 172 to a position on the end surface of the lower electrode assembly 120 away from the winding core through hole 121 , thereby further improving the wetting effect of the electrode in the radially outer region of the winding core through hole 121 .

[0065] Specifically, see Figures 9 to 11 In one example of the secondary battery 100 of the present invention, the through groove 172 includes a second groove 1721 provided on the second cover plate 142. The second groove 1721 is located on the side of the second cover plate 142 facing the first cover plate 141. At least a portion of the second groove 1721 is exposed to the first through hole 1411. Another portion of the second groove 1721 extends along the radial direction of the secondary battery 100 and forms a groove opening 17211 facing the outer periphery of the second cover plate 142. In this embodiment, the second groove 1721 can be a groove structure formed by removing material along the thickness direction of the second cover plate 142, such as Figure 10 In another embodiment, the through groove 172 may also be a groove structure formed by machining a notch on the second cover plate 142 and then blocking the side of the notch facing the electrode assembly 120 with a baffle, as shown in FIG. Figure 11 As shown. The second groove 1721 can be in the shape of a roughly elongated groove extending in the radial direction of the second cover plate 142, or can be in the shape of a roughly rectangular groove, etc. Optionally, in this embodiment, the second groove 1721 is in the shape of a roughly elongated groove, and along the length direction of the second groove 1721, one end of the second groove 1721 is exposed to the first through-hole 1411, and the other end of the second groove 1721 extends in the radial direction of the secondary battery 100 and forms a groove opening 17211 facing the outer periphery of the second cover plate 142. When liquid is injected through the second groove 1721, the electrolyte enters from the end of the second groove 1721 that is connected to the first through-hole 1411, then flows out from the groove opening 17211 of the second groove 1721, and finally enters the end face area of the electrode assembly 120 below the groove opening 17211. The provision of the second groove 1721 can also improve the uniformity of liquid injection in the radial direction of the electrode assembly 120.

[0066] See also Figures 12 to 14 In one example of the secondary battery 100 of the present invention, the through groove 172 includes a first groove 1722 provided in the first cover plate 141. The first groove 1722 is located on the side of the first cover plate 141 facing the second cover plate 142. Along the radial direction of the secondary battery 100, one end of the first groove 1722 communicates with the first through hole 1411. The other end of the first groove 1722 extends radially and communicates with the end surface of the electrode assembly 120 below. The first groove 1722 can have a rectangular groove structure, a trapezoidal groove structure, a V-shaped groove structure, or the like extending radially along the secondary battery 100. Along the radial direction of the secondary battery 100, one end of the first groove 1722 penetrates the inner wall of the first through hole 1411 to communicate with the first through hole 1411. The other end of the first groove 1722 extends away from the first through hole 1411 and communicates with the end surface of the electrode assembly 120 below.

[0067] Specifically, see 12 to Figure 14 The first cover plate 141 includes a cover body 1413 and a second protrusion 1414. The cover body 1413 is arranged around the outer periphery of the second protrusion 1414, and the second protrusion 1414 protrudes toward the electrode assembly 120 relative to the cover body 1413. The first through hole 1411 passes through the central area of the second protrusion 1414, and the surface of the second protrusion 1414 facing the electrode assembly 120 abuts against the edge area of the second cover plate 142 below. The first groove 1722 is provided on the side of the second protrusion 1414 facing the electrode assembly 120, and passes through the area where the second protrusion 1414 protrudes from the cover body 1413 along the radial direction of the secondary battery 100. The number of first grooves 1722 is not limited, and can be one or multiple arranged around the first through hole 1411, which is determined according to the actual injection requirements. By setting the first groove 1722 on the first cover plate 141 , when electrolyte is injected through the first groove 1722 , the electrolyte enters from the end of the first groove 1722 connected to the first through hole 1411 and then enters the end surface area of the electrode assembly 120 below.

[0068] It should be noted that, under the premise of meeting the liquid injection requirements of the electrode assembly 120, the second groove 1721 may be provided only on the second cover plate 142, such as Figure 9 Alternatively, the first groove 1722 may be provided only on the first cover plate 141, as shown in FIG. Figure 14 Alternatively, the second groove 1721 may be provided on the second cover plate 142, and the first groove 1722 may be provided on the first cover plate 141, as shown. Figure 12 shown.

[0069] See also Figure 2 、 Figure 16 and Figure 21In an example of the secondary battery 100 of the present invention, along the axial direction of the secondary battery 100, the current collecting component 130 includes a current collecting body 131 and a cover plate welding portion 132. The current collecting body 131 is arranged around the outer periphery of the cover plate welding portion 132. The current collecting body 131 is conductively connected to the cover plate welding portion 132. The conductive connection method can be a welding connection or an integral molding connection, and there is no specific limitation on this. The current collecting body 131 is welded to the first pole ear 122 below to achieve electrical connection with the electrode assembly 120. The cover plate welding portion 132 abuts against the second cover plate 142 and is welded to form a first weld mark 1421. The first weld mark 1421 is spaced apart from the injection hole 170, that is, along the axial direction of the secondary battery 100, the projection of the first weld mark 1421 does not overlap with the projection of the injection hole 170, as shown in FIG. Figure 21 As shown. The specific distribution position and weld track of the first weld mark 1421 are not restricted, and are subject to the welding strength requirements between the current collecting component 130 and the second cover plate 142. This arrangement can avoid positional interference between the injection hole 170 and the first weld mark 1421. The surface of the first weld mark 1421 is coated with a sealant. This arrangement can fix the welding slag at the position of the first weld mark 1421 on the surface of the second cover plate 142 by the sealant, thereby preventing the electrolyte overflowing from the injection hole 170 during the injection process from carrying the welding slag back into the injection hole 170, thereby reducing the risk of failure of the secondary battery 100.

[0070] See also Figure 2 In one example of the secondary battery 100 of the present invention, the sealing plate 160 covers the first weld mark 1421. This configuration allows the sealing plate 160 to simultaneously cover the liquid injection hole 170 and the first weld mark 1421. This not only seals the liquid injection hole 170 but also prevents corrosion of the first weld mark 1421, thereby ensuring the weld strength of the first weld mark 1421.

[0071] See also Figure 8 、 Figure 17 and Figure 18In one example of the secondary battery 100 of the present invention, the thickness of the cover plate welding portion 132 is greater than the thickness of the current collecting body 131, and the cover plate welding portion 132 protrudes relative to the current collecting body 131 toward the second cover plate 142. The central region of the cover plate welding portion 132 includes a central hole 1321 that communicates with the winding core through-hole 121. The central hole 1321 can be coaxial with the winding core through-hole 121, or it can be coaxial with the winding core through-hole 121. Preferably, to facilitate the positioning and installation between the cover plate welding portion 132 and the winding core through-hole 121, in this embodiment, the central hole 1321 is coaxial with the winding core through-hole 121. The edge region of the cover plate welding portion 132 includes a third groove 1322. The third groove 1322 extends in the radial direction of the cover plate welding portion 132. One end of the third groove 1322 communicates with the central hole 1321 to achieve communication with the winding core through-hole 121; the other end of the third groove 1322 communicates with the injection hole 170. It should be noted that, on the radially outer side of the cover plate welding portion 132, a gas storage space 124 is formed between the first cover plate 141 and the end surface of the electrode assembly 120. Figure 8 In this embodiment, the third groove 1322 is connected to the liquid injection hole 170 , specifically, the third groove 1322 is connected to the gas storage space 124 , thereby achieving communication between the third groove 1322 and the liquid injection hole 170 .

[0072] By setting a third groove 1322 on the cover plate welding portion 132, when the electrolyte is injected into the interior of the electrode assembly 120 through the injection hole 170, the electrolyte will partially fill the gas storage space 124 in the later stage of injection. At this time, the electrolyte in the gas storage space 124 can flow into the core through hole 121 through the third groove 1322, thereby realizing the injection of liquid in the central area of the electrode assembly 120. This not only improves the wetting speed of the central area of the electrode assembly 120, but also improves the uniformity of the injection inside the electrode assembly 120.

[0073] See also Figures 18 to 20In one example of the secondary battery 100 of the present invention, the outer periphery of the first cover plate 141 further includes a first protrusion 1412 that matches the opening 112. The first protrusion 1412 protrudes toward the electrode assembly 120 and is welded to the current collecting member 130. The first protrusion 1412 surrounds the outer periphery of the cover body 1413. The first protrusion 1412 can be integrally stamped and connected to the cover body 1413, or welded. The outer periphery of the first protrusion 1412 matches the shape of the sidewall 111 of the housing 110. The outer periphery of the first protrusion 1412 is circumferentially opposed to the inner wall of the sidewall 111. This allows the sidewall 111 and the first protrusion 1412 to be welded externally to the housing 110, achieving a sealed connection between the outer periphery of the first cover plate 141 and the sidewall 111. The surface of the first protrusion 1412 facing the electrode assembly 120 abuts and is welded to the surface of the current collecting member 130 below facing away from the electrode assembly 120. This arrangement allows the welding position between the current collecting member 130 and the first cover plate 141 to be set away from the injection hole 170 at the first through hole 1411, thereby reducing the probability of welding slag entering the injection hole 170 along with the electrolyte. At the same time, since the outer periphery of the current collecting member 130 is welded to the first cover plate 141, the central area of the current collecting member 130 does not need to be provided with the cover plate welding portion 132, as shown in FIG. Figure 19 and Figure 20 As shown, with this arrangement, the electrolyte in the gas storage space 124 can flow into the winding core through-hole 121 without the need to provide the third groove 1322 , thereby further improving the wetting speed and uniformity of the electrode assembly 120 .

[0074] See also Figure 22 In one embodiment of the battery pack 200 of the present invention, the battery pack 200 includes a housing 210 and at least one secondary battery 100. The housing 210 includes a first housing portion 211 and a second housing portion 212. The first housing portion 211 and the second housing portion 212 overlap to form a storage space. Multiple secondary batteries 100 are accommodated in the storage space. The multiple secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 can be, for example, a battery module, a battery pack, or the like.

[0075] See also Figure 23In one example of an electronic device 300 of the present invention, the electronic device 300 includes a working unit 310 and a battery pack 200. The working unit 310 is electrically connected to the battery pack 200 to obtain electrical energy. The working unit 310 can be a unit component that can obtain electrical energy from the battery pack 200 and perform corresponding operations, such as the blade rotation unit of a fan, the dust collection unit of a vacuum cleaner, or the wheel drive unit of an electric vehicle. The electronic device 300 can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.; spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship 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. The embodiment of the present utility model does not impose any special restrictions on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of the present utility model, the electronic device 300 is a vehicle, the working part 310 is the body of the vehicle, and the battery pack 200 is fixedly installed on the body, thereby providing driving force for the vehicle to realize the operation of the vehicle.

[0076] In the secondary battery of the present invention, since the projection of the injection hole is located on the periphery of the winding core through hole along the axial direction of the secondary battery, the injection hole and the winding core through hole can be offset in the radial direction. With this arrangement, when the electrolyte is injected through the injection hole, the impact force generated by the high-speed electrolyte will be absorbed by the collecting component or the end face of the electrode assembly at the position opposite the injection hole. This can slow down the impact of the liquid flow on the winding core through hole position, correspondingly reduce the probability of collapse at the winding core through hole position, and improve the integrity of the electrode interface at this position, thereby improving the charge and discharge performance and cycle stability of the secondary battery. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance. The above embodiments only illustrate the principle and effect of the present invention, and are not used to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A secondary battery, characterized in that: include: A housing comprising a side wall and a cover assembly, wherein one end of the side wall along the axial direction of the secondary battery comprises an opening, and the cover assembly seals the opening; The cover plate assembly includes: a first cover plate and a second cover plate, the first cover plate covers the opening and is sealed with the side wall; the first cover plate includes a first through hole; the second cover plate at least partially covers the first through hole; the second cover plate is welded to the first cover plate; an electrode assembly, sealed and mounted in the housing, the electrode assembly having a winding core through-hole; a current collecting member, disposed on a side of the electrode assembly facing the cover plate assembly, and electrically connected to the electrode assembly and the housing, respectively; a sealing plate, disposed on a side of the second cover plate facing away from the electrode assembly; The first cover plate and / or the second cover plate is provided with a liquid injection hole, and along the axial direction of the secondary battery, the projection of the liquid injection hole is located at the periphery of the winding core through hole; the sealing plate seals the liquid injection hole.

2. The secondary battery according to claim 1, wherein The liquid injection hole includes a second through hole provided in the second cover plate, at least a portion of the second through hole is exposed to the first through hole, and at least another portion is communicated with the end surface of the electrode assembly located at the opening side.

3. The secondary battery according to claim 2, wherein Along the axial direction of the secondary battery, the second cover plate is arranged between the first cover plate and the current collecting member, and the outer edge of the second cover plate abuts against the outer periphery of the first through hole; the surface of the first cover plate facing the electrode assembly at least partially blocks the second through hole.

4. The secondary battery according to claim 3, wherein The second through hole extends in a radial direction of the secondary battery and passes through an outer edge of the second cap plate.

5. The secondary battery according to claim 1, wherein Along the axial direction of the secondary battery, the second cover plate is arranged between the first cover plate and the current collecting member, and the outer edge of the second cover plate abuts the outer peripheral edge of the first through hole; the injection hole includes a through groove provided on the first cover plate and / or the second cover plate, one end of the through groove is connected to the first through hole, and the other end extends along the radial direction of the secondary battery and is connected to the end face of the electrode assembly located on the opening side.

6. The secondary battery according to claim 5, characterized in that The through slot includes a second groove provided on the second cover plate, the second groove is located on a side of the second cover plate facing the first cover plate, and at least a portion of the second groove is exposed to the first through hole.

7. The secondary battery according to claim 5, characterized in that The through slot includes a first groove provided on the first cover plate, the first groove is located on a side of the first cover plate facing the second cover plate, and the first groove is communicated with the first through hole.

8. The secondary battery according to any one of claims 1 to 7, characterized in that The current collecting component includes a current collecting body and a cover plate welding portion. The cover plate welding portion is welded to the second cover plate to form a first weld mark. The first weld mark is spaced apart from the liquid injection hole, and a surface of the first weld mark is coated with sealant.

9. The secondary battery according to claim 8, characterized in that The sealing plate covers the first weld print.

10. The secondary battery according to claim 8, wherein The thickness of the cover plate welding part is greater than the thickness of the collecting body, and the cover plate welding part protrudes toward the second cover plate side relative to the collecting body; the central area of the cover plate welding part includes a central hole connected to the core through hole, and the edge area of the cover plate welding part includes a third groove, and the two ends of the third groove are respectively connected to the injection hole and the central hole.

11. A battery pack, characterized in that: The battery pack includes the secondary battery according to any one of claims 1 to 10.

12. An electronic device, characterized in that: The electronic device includes the battery pack according to claim 11.

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