Secondary batteries, battery packs, and electronic devices

Abstract

The present invention provides a secondary battery, battery pack, and electronic device that improve the problem of indentation easily occurring at the through-hole position of the wound body of the electrode member during the liquid injection process. [Solution] The secondary battery includes a case, electrode members, a current collector member, and a sealing plate. The case includes a side wall with an opening and a cover plate member. The cover plate member seals the opening. The cover plate member includes first and second cover plates, the first cover plate fitted into the opening, sealed with the side wall, and includes a first through hole. The second cover plate shields the first through hole and is welded to the first cover plate. The electrode members are installed inside the case and have a winding through hole. The current collector member is installed on the side of the electrode members facing the cover plate member and electrically connects the electrode members to the case. The sealing plate is installed on the side of the second cover plate facing away from the electrode members and seals the liquid injection hole. The first cover plate and / or the second cover plate have the liquid injection hole, and the projection of the liquid injection hole is located on the outer circumference of the winding through hole.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and more specifically, to secondary batteries, battery packs, and electronic devices.

Background Art

[0002] In the prior art, a method of injecting liquid from the center is usually adopted for secondary batteries, and the liquid injection hole is provided at the position of the through hole of the wound body of the electrode structure. When this liquid injection method is used, when injecting liquid into the battery case, the electrolyte with a high flow rate is likely to directly flow into the inside of the through hole of the wound body, and local depressions are likely to occur at the position of the through hole of the wound body, affecting the integrity of the electrode sheet interface, and further reducing the charge and discharge performance and cycle stability of the secondary battery. At the same time, in the process of liquid injection, the electrolyte needs to penetrate into the separator first and then penetrate through the separator and into the electrode sheet during the flow process inside the secondary battery, so the penetration rate of the electrode member is limited.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The present invention provides a secondary battery, a battery pack, and an electronic device that improve the technical problem that depressions are likely to occur at the position of the through hole of the wound body of the electrode member during the liquid injection process.

Means for Solving the Problems

[0004] To achieve the above-mentioned objectives and other related objectives, the present invention provides a secondary battery comprising a case, an electrode member, a current collector member and a sealing plate, wherein the case comprises a side wall and a cover plate member, the side wall comprising an opening along one axial end of the secondary battery, the cover plate member sealing the opening, the cover plate member comprising a first cover plate and a second cover plate, the first cover plate fitted into the opening and sealed with the side wall, the first cover plate comprising a first through hole, and the second cover plate comprising at least a portion of the first through hole. The second cover plate is welded to the first cover plate, the electrode members are sealed inside the case and have through-holes for the windings, the current collector is installed on the side of the electrode members facing the cover plate members and is electrically connected to the electrode members and the case respectively, the sealing plate is installed on the side of the second cover plate facing away from the electrode members, the first cover plate and / or the second cover plate are provided with liquid injection holes, the projection of the liquid injection holes is located on the outer circumference of the through-holes for the windings along the axial direction of the secondary battery, and the sealing plate seals the liquid injection holes.

[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 communicates with the end face located on the opening side of the electrode member.

[0006] In an example of the secondary battery of the present invention, the second cover plate is installed between the first cover plate and the current collector along the axial direction of the secondary battery, the outer edge of the second cover plate abuts against the outer edge of the first through hole, and the surface of the first cover plate facing the electrode member at least partially shields the second through hole.

[0007] In an example of the secondary battery of the present invention, the second through-hole extends radially through the secondary battery and penetrates the outer edge of the second cover plate.

[0008] In an example of the secondary battery of the present invention, a second cover plate is installed between a first cover plate and a current collector along the axial direction of the secondary battery, the outer edge of the second cover plate abuts against the outer edge of the first through hole, and the liquid injection hole includes a through groove installed in the first cover plate and / or the second cover plate, one end of the through groove communicates with the first through hole, and the other end extends radially in the secondary battery and communicates with the end face located on the opening side of the electrode member.

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

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

[0011] In an example of the secondary battery of the present invention, the current collector member includes a current collector body and a cover plate welded portion, the cover plate welded portion is welded to a second cover plate to form a first weld mark, the first weld mark is positioned at a distance from the liquid injection hole, and a sealant is applied to the surface of the first weld mark.

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

[0013] In an example of the secondary battery of the present invention, the thickness of the cover plate weld is greater than the thickness of the current collector body, the cover plate weld protrudes toward the second cover plate relative to the current collector body, the central region of the cover plate weld includes a central hole that communicates with the winding body through hole, the edge region of the cover plate weld includes a third groove, and both ends of the third groove communicate with the liquid injection hole and the central hole, respectively.

[0014] The present invention further provides a battery pack including a secondary battery in any of the above examples.

[0015] The present invention further provides an electronic device including a battery pack in the above example. [Effects of the Invention]

[0016] In the secondary battery of the present invention, the projection of the electrolyte injection hole is located on the outer circumference of the winding body through hole along the axial direction of the secondary battery, thereby enabling the electrolyte injection hole and the winding body through hole to be offset radially. By installing them in this way, when the electrolyte is injected through the electrolyte injection hole, the impact force generated from the electrolyte at high speed is absorbed by the end face of the current collector or electrode member at the front position of the electrolyte injection hole, thereby mitigating the impact of the liquid flow on the winding body through hole position, and correspondingly reducing the probability of collapse at the winding body through hole position, improving the integrity of the electrode sheet interface at that position, and thereby improving the charge / discharge performance and circulation stability of the secondary battery. [Brief explanation of the drawing]

[0017] To more clearly illustrate embodiments of the present invention or technical solutions in the prior art, the drawings necessary for use in describing embodiments or related technologies are briefly introduced below. Clearly, the drawings described below represent only embodiments of the present application, and those skilled in the art can obtain other embodiments based on these drawings without expending any creative effort.

[0018] [Figure 1] This is a cross-sectional view of the overall structure of one embodiment of the secondary battery of the present invention. [Figure 2] This is a magnified view of area A in Figure 1. [Figure 3] This is a partial cross-sectional view showing a second cover plate with a second through-hole in one embodiment of the secondary battery of the present invention. [Figure 4] This is a diagram illustrating the structure of the second cover plate in the embodiment shown in Figure 3. [Figure 5] This is a partial cross-sectional view showing a second cover plate with a second through-hole in another embodiment of the secondary battery of the present invention. [Figure 6]It is an explanatory diagram of the structure of the second cover plate in the embodiment of FIG. 5. [Figure 7] It is an explanatory diagram in which the liquid injection hole after removing the sealing plate is at the first through hole in one embodiment of the secondary battery of the present invention. [Figure 8] It is a partial cross-sectional view of the second cover plate in one embodiment of the secondary battery of the present invention, where a through groove is provided. [Figure 9] It is a three-dimensional partial cross-sectional view of the second cover plate in one embodiment of the secondary battery of the present invention, where a through groove is provided. [Figure 10] It is an explanatory diagram of the structure of the second cover plate in one embodiment of the secondary battery of the present invention, where a first groove is provided. [Figure 11] It is an explanatory diagram of the structure of the second cover plate in another embodiment of the secondary battery of the present invention, where a first groove is provided. [Figure 12] It is a partial cross-sectional view of the first cover plate in one embodiment of the secondary battery of the present invention, where a second groove is provided. [Figure 13] It is an explanatory diagram of the three-dimensional structure of the first cover plate in one embodiment of the secondary battery of the present invention in one angular direction. [Figure 14] It is an explanatory diagram of the three-dimensional structure of the first cover plate in one embodiment of the secondary battery of the present invention in another angular direction. [Figure 15] It is an explanatory diagram of the structure in which the through groove is located at the first through hole after removing the sealing plate in one embodiment of the secondary battery of the present invention. [Figure 16] It is an explanatory diagram of the overall structure of the current collector member in one embodiment of the secondary battery of the present invention. [Figure 17] It is an explanatory diagram of the overall structure of the current collector member in one embodiment of the secondary battery of the present invention, where a third groove is provided. [Figure 18] It is a partial cross-sectional view of the current collector member in one embodiment of the secondary battery of the present invention, where a third groove is provided. [Figure 19] It is an explanatory diagram of the structure of the current collector member in one embodiment of the secondary battery of the present invention, where no cover plate welding part is provided. [Figure 20]This is a partial cross-sectional diagram illustrating one embodiment of the secondary battery of the present invention, in which a cover plate weld is not installed on the current collector member. [Figure 21] This is an explanatory diagram showing the distribution of first weld marks on a second cover plate in one embodiment of the secondary battery of the present invention. [Figure 22] This is a diagram illustrating the overall structure of one embodiment of the battery pack of the present invention. [Figure 23] This is a diagram illustrating the structure of the battery pack of the present invention installed in a vehicle. [Modes for carrying out the invention]

[0019] The following describes implementations of the present invention through specific examples, so that those skilled in the art can easily understand other advantages and effects of the present invention as disclosed herein. The present invention can be implemented or applied in yet another different specific implementation, and the details of each item herein can be modified or changed in various ways based on different perspectives and applications without departing from the spirit of the invention. Where there is no conflict, the following embodiments and features within the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for describing specific specific implementations and are not intended to limit the scope of protection of the present invention. Test methods in the embodiments below that do not specify concrete conditions are usually carried out according to general conditions or according to conditions recommended by each manufacturer.

[0020] When this embodiment provides a numerical range, it should be understood that, unless otherwise stated in the invention, any numerical value at both endpoints of each numerical range and any value between the endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those understood by the articulate person to the existing art and as described in this invention, and furthermore, the invention can be realized using any existing methods, equipment and materials that are similar or equivalent to the methods, equipment and materials described in the embodiments of this invention.

[0021] Furthermore, terms such as "up," "down," "left," "right," "middle," and "one" cited herein are merely for the purpose of clarifying the explanation and are not used to limit the scope within which the present invention can be implemented. Any changes or adjustments to their relative relationships should be considered to fall within the scope within which the present invention can be implemented without any substantial change in technical content.

[0022] Referring to 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 electrolyte injection hole 170 is located on the outer circumference of the winding body through hole 121, thereby enabling a radially offset installation of the electrolyte injection hole 170 and the winding body through hole 121. In this way, direct flow of electrolyte into the winding body through hole 121 during the electrolyte injection process can be avoided, thereby mitigating the impact of the liquid flow on the winding body through hole 121, reducing the probability of depression appearing at the winding body through hole 121, and improving the charge / discharge performance and circulation stability of the secondary battery 100.

[0023] Referring to Figures 1 and 2, the secondary battery 100 includes a case 110, an electrode member 120, a current collector member 130, and a sealing plate 160.

[0024] A storage space is formed inside the case 110 and is used to house the electrode member 120, electrolyte (not shown), and other components. The storage space may have an opening 112 at one end or openings 112 at both ends. Specifically, the dimensions of the case 110 can be determined based on the specific dimensions of the electrode member 120, for example, a diameter of 46 mm and a height of 80 mm, 95 mm, or 120 mm. The case 110 may have various shapes, for example, cylindrical or prismatic. The material of the case 110 may also be various, for example, copper, iron, aluminum, steel, or aluminum alloy. To prevent the case 110 from rusting during long-term use, a layer of rust-preventive material, such as metallic nickel, may be plated onto the surface of the case 110.

[0025] Referring to Figure 1, in one embodiment of the secondary battery 100 of the present invention, the case 110 has a cylindrical structure and includes an end wall 113, a side wall 111 surrounding the end wall 113, and a cover plate member 140. Along the height direction of the case 110, one end of the side wall 111 is fixedly connected to the end wall 113 to form a closed end, and an opening 112 is provided at the other end of the side wall 111. The cover plate member 140 is installed in the opening 112 and seals the opening 112.

[0026] As shown in Figures 1 and 2, the electrode member 120 is housed in the case 110. The electrode member 120 is a component in the secondary battery 100 where an electrochemical reaction occurs. The electrode member 120 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually placed between the positive electrode sheet and the negative electrode sheet. Preferably, in this embodiment, the electrode member 120 consists of a winding of a positive electrode sheet, a negative electrode sheet and a separator, and a winding through hole 121 is formed in the central region of the electrode member 120. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is applied to the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode coating region and a positive electrode tab connected to the positive electrode coating region, the positive electrode active material layer is applied to the positive electrode coating region, and the positive electrode active material layer is not applied to the positive electrode tab. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is applied to the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode coating region and a negative electrode tab connected to the negative electrode coating region. The negative electrode coating region is coated with a negative electrode active material layer, while the negative electrode tab is not coated with the negative electrode active material layer. Taking a lithium-ion battery as an example, the positive electrode current collector may be made of aluminum, and the positive electrode active material layer contains a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode current collector may be made of copper, and the negative electrode active material layer contains a negative electrode active material, which may be carbon or silicon. The main substrate of the separator may be PP or PE. To provide protection and insulation to the electrode member 120, an insulating film may be coated on the outside of the electrode member 120, and the insulating film may be made of PP, PE, PET, PVC, or other polymer materials.

[0027] Referring to Figure 1, in one embodiment of the secondary battery 100 of the present invention, the electrode member 120 is sealed and installed inside the case 110, and a first tab 122 and a second tab 123 are provided at both ends of the electrode member 120 in the longitudinal direction, the polarities of the first tab 122 and the second tab 123 are opposite, the first tab 122 faces the opening 112 of the case 110, and the first tab 122 is the negative electrode tab. In other embodiments, the first tab 122 may be the positive electrode tab and the second tab 123 may be the negative electrode tab.

[0028] Referring to Figure 1, in one embodiment of the secondary battery 100 of the present invention, a through-terminal mounting hole is provided on the end wall 113 of the case 110, and the electrode terminal 150 is inserted into the terminal mounting hole in a sealed and insulated manner. The mounting method of the electrode terminal 150 on the end wall 113 is not limited as long as sealed insulation between the electrode terminal 150 and the end wall 113 can be achieved. The side of the electrode member 120 facing the end wall 113 has a second tab 123, and one end of the electrode terminal 150 may be directly welded to the second tab 123, or conductively connected to the second tab 123 via a current collector member, and there are no specific limitations on this.

[0029] Referring to Figure 2, in one embodiment of the secondary battery 100 of the present invention, the current collector member 130 is installed inside the case 110 and is located on the side of the electrode member 120 facing the cover plate member 140, and the current collector member 130 is welded to the first tab 122 and the case 110 to achieve electrical connection. The current collector member 130 may be welded to the cover plate member 140, to the side wall 111, or to the cover plate member 140 and the side wall 111 simultaneously. The specific location and welding area of ​​the welding between the current collector member 130 and the first tab 122 are not limited, as long as a stable electrical connection requirement between the current collector member 130 and the first tab 122 can be achieved.

[0030] Referring to Figures 2 and 3, the cover plate member 140 includes a first cover plate 141 and a second cover plate 142. The first cover plate 141 is fitted into the opening 112, and the outer edge of the first cover plate 141 is sealed to the side wall 111 of the case 110. There are various sealing methods, such as welded sealing and mechanical pressure welding sealing. The first cover plate 141 includes a first through hole 1411, which may be located in the central region of the first cover plate 141 or offset from the central region. There are also various shapes for the first through hole 1411, such as a square hole, a round hole or other irregularly shaped hole. Preferably, in this embodiment, to facilitate the machining positioning of the first through hole 1411 on the first cover plate 141, the first through hole 1411 is a round hole structure and is coaxially installed with the first cover plate 141.

[0031] Referring again to Figures 2 and 3, the second cover plate 142 is installed on the side of the current collector member 130 that is away from the electrode member 120, and the second cover plate 142 shields the first through hole 1411 at least partially. 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 may be located on the side of the first cover plate 141 that is away from the electrode member 120, or on the side of the first cover plate 141 that is facing the electrode member 120, as long as it can partially shield the first through hole 1411. The second cover plate 142 may be a disc shape corresponding to the first through hole 1411, or it may be any other shape that can shield the first through hole 1411, such as a rectangular plate or a polygonal plate.

[0032] The current collector 130 may be welded to the first cover plate 141 or to the second cover plate 142, as long as an electrical connection can be achieved between the current collector 130 and the first cover plate 141.

[0033] Referring to Figure 2, in one embodiment, the first cover plate 141 is provided with an injection hole 170. The shape of the injection hole 170 is not limited and may be, for example, a round hole, an elongated hole, or a through groove. In other embodiments, the injection hole 170 may be provided on the second cover plate 142. In yet another embodiment, the injection hole 170 may be provided on both the first cover plate 141 and the second cover plate 142. The specific installation location of the injection hole 170 is not limited as long as the liquid injection requirement of the secondary battery 100 is satisfied. The sealing plate 160 is installed on the side of the second cover plate 142 that is away from the electrode member 120, and the sealing plate 160 seals the injection hole 170. The sealing plate 160 may be sealed with the first cover plate 141 or sealed with the second cover plate 142, as long as the sealing plate 160 ensures that the injection hole 170 can be sealed.

[0034] Referring to Figure 2, along the axial direction of the secondary battery 100, the projection of the electrolyte injection hole 170 is located on the outer circumference of the winding body through hole 121, that is, the projection of the electrolyte injection hole 170 and the projection of the winding body through hole 121 do not overlap. By installing them in this manner, it is possible to achieve offset installation of the electrolyte injection hole 170 and the winding body through hole 121 in the radial direction of the secondary battery 100. When the electrolyte is injected through the electrolyte injection hole 170, the impact force of the liquid flow generated by the electrolyte is absorbed by the end face of the current collector member 130 or electrode member 120 at the position directly opposite the electrolyte injection hole 170. This mitigates or avoids the impact of the liquid flow received at the winding body through hole 121, thereby reducing the probability of partial depression appearing at the winding body through hole 121, improving the integrity of the electrode sheet interface at that location, and further improving the charge / discharge performance and circulation stability of the secondary battery 100. At the same time, since the electrolyte injection hole 170 can either enter directly into the end face of the electrode member 120 below, or enter into the end face of the electrode member 120 after passing through the current collector 130, this method allows the electrolyte to permeate into the electrode member 120 from the end face tab laminate layer of the electrode member 120, compared to the method in which the electrolyte enters directly into the inside of the electrode member 120 from the winding body through hole 121. This improves the penetration rate of the electrolyte inside the electrode member 120, and at the same time improves the exhaust rate inside the case 110 during the chemical conversion process, further improving the production efficiency of the secondary battery 100.

[0035] Referring to Figures 2 to 4, in one embodiment of the secondary battery 100 of the present invention, the liquid injection hole 170 includes a second through hole 171 installed in the second cover plate 142, where at least a portion of the second through hole 171 is exposed to the first through hole 1411, and at least another portion communicates with the end face of the electrode member 120 located on the opening 112 side. The second through hole 171 may be completely exposed to the first through hole 1411, or it may be partially exposed to the first through hole 1411. The communication between the second through hole 171 and the end face of the electrode member 120 refers to the communication between the second through hole 171 and the end face of the electrode member 120 located on the opening 112 side. The second through hole 171 may communicate directly with the end face of the electrode member 120 below, or it may communicate indirectly with the end face of the electrode member 120 through a gap region provided in the current collector member 130. The second through hole 171 may be any shape, such as an elongated hole, a round hole, or a square hole. By providing the second through-hole 171, vertical communication between the injection hole 170 and the end face of the electrode member 120 can be achieved, shortening the length of the electrolyte flow path and further improving the flow velocity of the electrolyte entering the end face of the electrode member 120, which is advantageous for improving the penetration rate of the electrolyte inside the electrode member 120.

[0036] Specifically, referring to Figures 3 and 4, in this embodiment, the second through-hole 171 is an elongated hole, with one end of the elongated hole exposed within the first through-hole 1411 along its length, and the other end of the elongated hole extending radially outward along the secondary battery 100. By installing it in this manner, for the same area, the elongated hole has a longer extension along the radial direction of the electrode member 120, thereby improving the uniformity of electrolyte penetration in the radial direction of the end face of the electrode member 120, and resulting in a better electrolyte injection effect.

[0037] The number of second through-holes 171 may be one or multiple. Preferably, in one embodiment, multiple second through-holes 171 are provided to improve the uniformity of the liquid injected inside the electrode member 120, and the multiple second through-holes 171 are arranged along the axis of the electrode member 120, thereby obtaining a relatively uniform liquid injection effect in the circumferential direction of the electrode member 120.

[0038] Referring to Figures 2 and 3, in one embodiment of the secondary battery 100 of the present invention, the second cover plate 142 is installed between the first cover plate 141 and the current collector 130 along the axial direction of the secondary battery 100, and the outer edge of the second cover plate 142 extends below the outer peripheral edge of the first through hole 1411 and abuts against the surface of the outer peripheral edge of the first through hole 1411 facing the electrode member 120. The surface of the first cover plate 141 facing the electrode member 120 shields the second through hole 171 at least partially. With this installation, when electrolyte is injected from 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 face region of the electrode member 120 below the position where the second cover plate 142 and the first cover plate 141 abut, further enabling injection into the inside of the electrode member 120 and improving the uniformity of injection in the radial direction of the electrode member 120.

[0039] To further improve the electrolyte injection speed inside the electrode member 120, preferably, as shown in Figures 5 and 6, in one embodiment of the secondary battery 100 of the present invention, the second through-hole 171 extends along the radial direction of the secondary battery 100 and penetrates the outer edge of the second cover plate 142. By installing it in this manner, a through-opening 1711 is formed on the side of the second through-hole 171 away from the first through-hole 1411, and the installation of the through-opening 1711 reduces the resistance when the electrolyte enters the end face of the electrode member 120, thereby further improving the electrolyte injection speed inside the electrode member 120.

[0040] Unlike the embodiment shown in Figure 3, in one embodiment of the secondary battery 100 of the present invention, as shown in Figures 12 and 13, the liquid injection hole 170 includes a through groove 172 provided in the first cover plate 141, one end of the through groove 172 communicates with the first through hole 1411, and the other end extends along the radial direction of the secondary battery 100 and communicates with the end face located on the opening 112 side of the electrode member 120. The cross-sectional shape of the through groove 172 is not limited and may be, for example, a circular cross-section, a rectangular cross-section, etc. In another embodiment, the through groove 172 may be provided in the second cover plate 142, as shown in Figures 9 and 10. In yet another embodiment, the through groove 172 may be partially provided in the first cover plate 141 and partially provided in the second cover plate 142, as shown in Figure 15. By installing the through groove 172, when the electrolyte is injected through the injection hole 170, the electrolyte is transported through the through groove 172 to a position away from the winding body through hole 121 on the end face of the lower electrode member 120, thereby further improving the penetration effect of the electrode sheet in the radially outer region of the winding body through hole 121.

[0041] Specifically, referring to Figures 9 to 11, in one embodiment of the secondary battery 100 of the present invention, the through groove 172 includes a second groove 1721 provided in the second cover plate 142, the second groove 1721 is located on the side of the second cover plate 142 toward the first cover plate 141, the second groove 1721 is at least partially exposed to the first through hole 1411, the other portion of the second groove 1721 extends along the radial direction of the secondary battery 100 and forms a groove opening 17211 toward the outer peripheral edge of the second cover plate 142. In this embodiment, the second groove 1721 may be a groove structure formed by material removal processing along the thickness direction of the second cover plate 142, as shown in Figure 10. In another embodiment, the through groove 172 may be a groove structure formed by machining a notch in the second cover plate 142 and then sealing the side of the notch toward the electrode member 120 with a shielding plate, as shown in Figure 11. The second groove 1721 may be a substantially elongated groove shape extending along the radial direction of the second cover plate 142, or it may be a substantially rectangular groove shape, etc. Selectively, in this embodiment, the second groove 1721 has a substantially elongated groove structure, with one end of the second groove 1721 exposed to the first through hole 1411 along the longitudinal direction of the second groove 1721, and the other end of the second groove 1721 extending along the radial direction of the secondary battery 100, forming a groove opening 17211 toward the outer peripheral edge of the second cover plate 142. When the electrolyte is injected through the second groove 1721, it enters from one end where the second groove 1721 and the first through hole 1411 are in communication, then flows out from the groove opening 17211 of the second groove 1721, and finally enters the end face region of the electrode member 120 below the groove opening 17211. By installing the second groove 1721, the uniformity of the electrolyte injection in the radial direction of the electrode member 120 can also be improved.

[0042] Referring to Figures 12 to 14, in one embodiment of the secondary battery 100 of the present invention, the through groove 172 includes a first groove 1722 installed on the first cover plate 141, the first groove 1722 is located on the side of the first cover plate 141 toward the second cover plate 142, one end of the first groove 1722 communicates with the first through hole 1411 along the radial direction of the secondary battery 100, and the other end of the first groove 1722 extends along the radial direction and communicates with the end face of the lower electrode member 120. The first groove 1722 can be a rectangular groove structure, a trapezoidal groove structure, a V-shaped groove structure, etc., extending along the radial direction of the secondary battery 100, and one end of the first groove 1722 penetrates the inner wall of the first through hole 1411 and communicates with the first through hole 1411 along the radial direction of the secondary battery 100. The other end of the first groove 1722 extends toward one side away from the first through hole 1411 and communicates with the end face of the lower electrode member 120.

[0043] Specifically, referring to Figures 12 to 14, the first cover plate 141 includes a cover body portion 1413 and a second protrusion portion 1414. The cover body portion 1413 is installed in an annular shape around the outer circumference of the second protrusion portion 1414, and the second protrusion portion 1414 protrudes toward the electrode member 120 relative to the cover body portion 1413. The first through hole 1411 penetrates the central region of the second protrusion portion 1414, and the surface of the second protrusion portion 1414 facing the electrode member 120 abuts against the edge region of the lower second cover plate 142. The first groove 1722 is installed on the side of the second protrusion portion 1414 facing the electrode member 120 and penetrates the region in which the second protrusion portion 1414 protrudes from the cover body portion 1413 along the radial direction of the secondary battery 100. The number of first grooves 1722 installed is not limited; there may be one, or there may be multiple grooves installed in a ring-like arrangement surrounding the first through-hole 1411, and the specific number will be determined by the actual liquid injection requirements. By installing the first grooves 1722 on the first cover plate 141, when liquid is injected through the first grooves 1722, the electrolyte enters from one end where the first groove 1722 and the first through-hole 1411 are in communication, and then enters the lower electrode member 120 end face region.

[0044] Furthermore, under the premise that the fluid injection requirement of the electrode member 120 is met, the second groove 1721 may be installed only on the second cover plate 142, as shown in Figure 9. Alternatively, the first groove 1722 may be installed only on the first cover plate 141, as shown in Figure 14. In addition, the second groove 1721 may be installed on the second cover plate 142 and the first groove 1722 may be installed on the first cover plate 141, as shown in Figure 12.

[0045] Referring to Figures 2, 16, and 21, in one embodiment of the secondary battery 100 of the present invention, along the axial direction of the secondary battery 100, the current collector member 130 includes a current collector body 131 and a cover plate welded portion 132, the current collector body 131 is installed annularly around the outer circumference of the cover plate welded portion 132, and the current collector body 131 and the cover plate welded portion 132 are electrically connected, the conductive connection method may be a welded connection or an integrally molded connection, and is not specifically limited thereto. The current collector body 131 is welded to a lower first tab 122 to realize an electrical connection with the electrode member 120. The cover plate welded portion 132 abuts against a second cover plate 142 and is welded to form a first weld mark 1421. The first weld mark 1421 is spaced apart from the liquid injection hole 170, that is, along the axial direction of the secondary battery 100, the projection of the first weld mark 1421 and the projection of the liquid injection hole 170 do not overlap, as shown in Figure 21. The specific distribution location and welding trajectory of the first weld marks 1421 are not limited, and the criterion is that the welding strength requirement between the current collector member 130 and the second cover plate 142 is met. By installing in this manner, positional interference between the liquid injection hole 170 and the first weld marks 1421 can be avoided. A sealant is applied to the surface of the first weld marks 1421. By installing in this manner, the welding slag at the location of the first weld marks 1421 can be fixed to the surface of the second cover plate 142 through the sealant, thereby preventing electrolyte that overflows from the liquid injection hole 170 during the liquid injection process from carrying the welding slag back into the liquid injection hole 170, and further reducing the risk of failure of the secondary battery 100.

[0046] Referring to Figure 2, in one embodiment of the secondary battery 100 of the present invention, the sealing plate 160 covers and seals the first weld mark 1421. By installing it in this manner, the sealing plate 160 can cover and seal both the liquid injection hole 170 and the first weld mark 1421 simultaneously, thereby sealing the liquid injection hole 170, preventing corrosion of the first weld mark 1421, and ensuring the welding strength of the first weld mark 1421.

[0047] Referring to Figures 8, 17, and 18, in one embodiment of the secondary battery 100 of the present invention, the thickness of the cover plate weld 132 is greater than the thickness of the current collector body 131, and the cover plate weld 132 protrudes toward the second cover plate 142 relative to the current collector body 131. The central region of the cover plate weld 132 includes a central hole 1321 that communicates with the winding body through hole 121, and the central hole 1321 may be installed coaxially with the winding body through hole 121 or on different axes. Preferably, in this embodiment, the central hole 1321 is installed coaxially with the winding body through hole 121 in order to facilitate positioning and installation between the cover plate weld 132 and the winding body through hole 121. The edge region of the cover plate weld 132 includes a third groove 1322, which extends radially along the cover plate weld 132. One end of the third groove 1322 communicates with the central hole 1321, thereby achieving communication with the winding body through hole 121, and the other end of the third groove 1322 communicates with the liquid injection hole 170. A gas storage space 124 is formed between the first cover plate 141 and the end face of the electrode member 120 on the radially outer side of the cover plate weld 132, as shown in Figure 8. In this embodiment, the communication between the third groove 1322 and the liquid injection hole 170 specifically refers to the communication between the third groove 1322 and the gas storage space 124, and further, the communication between the third groove 1322 and the liquid injection hole 170.

[0048] By installing a third groove 1322 in the cover plate weld 132, when the electrolyte is injected into the electrode member 120 through the injection hole 170, the electrolyte partially fills the gas storage space 124 in the later stages of injection. At this time, the electrolyte in the gas storage space 124 can flow through the third groove 1322 into the winding body through hole 121, and furthermore, injection of electrolyte into the central region of the electrode member 120 can be achieved. In this way, not only can the penetration rate of the central region of the electrode member 120 be improved, but the uniformity of the injected electrolyte inside the electrode member 120 can also be improved.

[0049] Referring to Figures 18 to 20, in one embodiment of the secondary battery 100 of the present invention, the outer peripheral edge of the first cover plate 141 further includes a first protrusion 1412 that fits into the opening 112, the first protrusion 1412 protrudes toward the electrode member 120 and is welded to the current collector member 130. The first protrusion 1412 is installed in an annular manner on the outer peripheral edge of the cover body 1413, and the first protrusion 1412 may be integrally press-formed and connected to the cover body 1413, or it may be welded. The outer peripheral surface shape of the first protrusion 1412 matches the shape of the side wall 111 of the case 110, the outer peripheral surface of the first protrusion 1412 and the inner wall of the side wall 111 are installed facing each other in the circumferential direction, and welding can be performed on the side wall 111 and the first protrusion 1412 outside the case 110, thereby achieving a sealed connection between the outer peripheral edge of the first cover plate 141 and the side wall 111. The surface of the first protrusion 1412 facing the electrode member 120 is welded to the surface of the lower current collector member 130 facing away from the electrode member 120. By installing it in this way, the welding position between the current collector member 130 and the first cover plate 141 can be moved away from the installation of the liquid injection hole 170 in the first through hole 1411, thereby reducing the probability that welding slag will enter the liquid injection hole 170 together with the electrolyte. At the same time, since the outer edge of the current collector member 130 is welded to the first cover plate 141, it is no longer necessary to install a cover plate weld 132 in the central region of the current collector member 130. As shown in Figures 19 and 20, by installing it in this way, the electrolyte in the gas storage space 124 can be allowed to flow into the wound body through hole 121 without the need to create a third groove 1322, thereby further improving the penetration speed and uniformity of penetration of the electrode member 120.

[0050] Referring to 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 section 211 and a second housing section 212, the first housing section 211 and the second housing section 212 are joined together to form a housing space, and multiple secondary batteries 100 are housed in the housing space, and the multiple secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 may be, for example, a battery module, a battery pack, etc.

[0051] Referring to Figure 23, in one embodiment of the electronic device 300 of the present invention, the electronic device 300 includes a work unit 310 and a battery pack 200, the work unit 310 being electrically connected to the battery pack 200 to receive power support. The work unit 310 can receive power from the battery pack 200 and may be a unit member that performs a corresponding task, such as a fan blade rotation unit, a vacuum cleaner dust collection unit, or a wheel drive unit in an electric vehicle. The electronic device 300 may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, or a power tool. The vehicle may be a fuel-powered vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle. The spacecraft includes airplanes, rockets, space shuttles, and spacecraft. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers. Embodiments of the present invention do not impose any special limitations on the electronic device 300 described above. In one embodiment of the electronic device 300 of the present invention, the electronic device 300 is a vehicle, the work unit 310 is the body of the vehicle, and the battery pack 200 is fixedly installed on the body to provide driving force to the vehicle and enable the operation of the vehicle.

[0052] In the secondary battery of the present invention, the projection of the electrolyte injection hole is located on the outer circumference of the winding body through hole along the axial direction of the secondary battery, thereby enabling a radially offset installation of the electrolyte injection hole and the winding body through hole. With this installation, when the electrolyte is injected through the electrolyte injection hole, the impact force generated by the electrolyte at high speed is absorbed by the end face of the current collector or electrode member at the position directly opposite the electrolyte injection hole. In this way, the impact of the liquid flow on the winding body through hole position can be mitigated, correspondingly reducing the probability of depression appearing at the winding body through hole position and improving the integrity of the electrode sheet interface at that position, thereby improving the charge / discharge performance and circulation stability of the secondary battery. Therefore, the present invention effectively overcomes some of the practical problems of the prior art and has very high utility and significance. The above-described embodiments exemplify the principles and effects of the present invention and do not limit the present invention. Those skilled in the art can modify or change the above-described embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical idea disclosed by the present invention should still be included in the rights claims of the present invention. [Industrial applicability]

[0053] The secondary battery of the present invention can achieve radially offset placement of the liquid injection hole and the winding body through hole, which mitigates the impact of the liquid flow on the winding body through hole position, reduces the probability of depression appearing at the winding body through hole position, improves the integrity of the electrode sheet interface at that position, and thereby improves the charge / discharge performance and circulation stability of the secondary battery. [Explanation of symbols]

[0054] 100 Secondary battery 110 cases 111 Side wall 112 Aperture 113 End wall 120 Electrode Member 121 Through hole in wound body 122 Tab 1 123 Second Tab 124 Gas storage space 130 Current collector 131 Current collector body 132 Cover plate weld 1321 Center hole 1322 Third groove 140 Cover plate component 141 First cover plate 1411 First through hole 1412 First protrusion 1413 Cover body 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 Box body 211 First box part 212 Second box part 300 Electronic equipment 310 Work Unit

Claims

1. It is a secondary battery, A case comprising a side wall and a cover plate member, wherein the side wall includes an opening along one axial end of the secondary battery, the cover plate member seals the opening, the cover plate member includes a first cover plate and a second cover plate, the first cover plate is fitted into the opening and sealed to the side wall, the first cover plate includes a first through hole, the second cover plate at least partially shields the first through hole, and the second cover plate is welded to the first cover plate, An electrode member having a winding through hole is sealed and installed inside the aforementioned case, A current collector is installed on the side of the electrode member facing the cover plate member and is electrically connected to the electrode member and the case, respectively. A sealing plate is installed on the side of the second cover plate facing away from the electrode member, Includes, The first cover plate and / or the second cover plate are provided with liquid injection holes, and along the axial direction of the secondary battery, the projection of the liquid injection holes is located on the outer circumference of the through-hole of the winding body. The aforementioned sealing plate is characterized by sealing the liquid injection hole.

2. The injection hole includes a second through-hole provided in the second cover plate. The secondary battery according to claim 1, characterized in that at least a portion of the second through hole is exposed to the first through hole, and at least another portion communicates with the end face located on the opening side of the electrode member.

3. Along the axial direction of the secondary battery, the second cover plate is installed between the first cover plate and the current collector, and the outer edge of the second cover plate abuts against the outer edge of the first through hole. The secondary battery according to claim 2, characterized in that the surface of the first cover plate facing the electrode member at least partially shields the second through hole.

4. The secondary battery according to claim 3, characterized in that the second through-hole extends radially through the secondary battery and penetrates the outer edge of the second cover plate.

5. Along the axial direction of the secondary battery, the second cover plate is installed between the first cover plate and the current collector, and the outer edge of the second cover plate abuts against the outer edge of the first through hole. The secondary battery according to claim 1, wherein the liquid injection hole includes a through groove provided in the first cover plate and / or the second cover plate, one end of the through groove communicates with the first through hole, and the other end extends radially of the secondary battery and communicates with the end face located on the opening side of the electrode member.

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

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

8. The secondary battery according to claim 1, characterized in that the current collector member includes a current collector body and a cover plate welded portion, the cover plate welded 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 sealant is applied to the surface of the first weld mark.

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

10. The thickness of the welded portion of the cover plate is greater than the thickness of the current collector body, and the welded portion of the cover plate protrudes toward the second cover plate relative to the current collector body. The secondary battery according to claim 8, characterized in that the central region of the cover plate weld includes a central hole communicating with the winding body through hole, the edge region of the cover plate weld includes a third groove, and both ends of the third groove communicate with the liquid injection hole and the central hole, respectively.

11. A battery pack characterized by including a secondary battery according to any one of claims 1 to 10.

12. An electronic device comprising the battery pack described in claim 11.

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