Secondary battery and electronic device

Abstract

To provide a secondary battery in which a buffer part is configured to absorb bending stress when a housing connection part is bent, and a problem of welding failure between a collector member and a tab is improved in a mechanical seal process of a cylindrical battery, and to provide an electronic device.SOLUTION: The rechargeable battery includes a case, an electrode member, a cap plate, and a current collecting member. The housing includes a surrounding sidewall. An opening is formed at one end of the side wall. One end of the side wall close to the opening includes a rolling groove recessed toward an interior of the housing. An electrode member is received in the housing, the electrode member including a tab facing the opening. The cap plate is attached to seal the opening. The current collecting member includes a current collecting body and a housing connecting portion provided at an outer peripheral edge of the current collecting body. The current collecting body is fixedly connected to the tab. The housing connection portion is bent toward an axial direction of the housing and is welded to a surface of the roll groove facing the electrode member. The current collecting member further includes a buffer portion connecting the casing connecting portion and the current collecting body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of batteries, and more particularly to secondary batteries and electronic devices. [Background technology]

[0002] Mechanical sealing is the mainstream packaging method for existing cylindrical batteries, and is widely used due to the advantages of mature technology and equipment and a fast production cycle. In conventional cylindrical batteries, a current collecting member is typically located near the opening of the housing. One end of the current collecting member is welded to the side wall of the housing, and the other end is electrically connected to the electrode tab of the electrode member, thereby achieving electrical connection between the housing and the electrode member. After this, the housing is mechanically sealed. This involves roll-pressing a roll groove recessed into the side wall of the housing and crimping a cap plate using an upsetting process. During this process, bending stresses generated in the current collecting member can cause the current collecting member's interior to lift, potentially causing the welded portion between the current collecting member and the electrode tab to peel off, resulting in a poor electrical connection of the electrode member. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the above-mentioned drawbacks of the prior art, the present invention provides a secondary battery and an electronic device that improve the technical problem of welding defects easily occurring between the current collecting member and the tab during the mechanical sealing process of a cylindrical battery. [Means for solving the problem]

[0004] To achieve the above and other related objectives, the present invention provides a secondary battery. The secondary battery includes a housing, an electrode member, a cap plate, and a current collecting member. The housing includes a surrounding sidewall, with an opening formed at one end of the sidewall. One end of the sidewall near the opening includes a roll groove recessed into the housing. The electrode member is housed within the housing, and the electrode member includes a tab facing the opening. The cap plate is attached to seal the opening. The current collecting member includes a current collecting body and a housing connecting portion provided on the outer periphery of the current collecting body. The current collecting body is fixedly connected to the tab. The housing connecting portion is bent toward the axis of the housing and welded to the surface of the roll groove facing the electrode member. The current collecting member further includes a buffer portion connecting the housing connecting portion to the current collecting body. The buffer portion is configured to absorb bending stress when the housing connecting portion is bent.

[0005] In the above technical solution, a buffer is provided between the housing connection part and the current collecting body, which can absorb bending stress generated when the housing connection part is bent, reduce the transmission of bending stress from the housing connection part to the fixed connection part between the current collecting body and the tab, and alleviate the problem of poor welding between the current collecting member and the tab caused by bending stress.

[0006] In one example of the secondary battery of the present invention, the buffer portion includes an arch-shaped protrusion that protrudes from the current collector body and extends circumferentially along the outer edge of the current collector body, and the side of the buffer portion facing the arch-shaped protrusion is formed as a recess.

[0007] In the above-mentioned technical solution, when the bending stress generated when the housing connection part is bent is transmitted to the current collecting body, the buffer part protruding from the current collecting body is pulled and deformed to become straight under the action of the bending stress, and can absorb part of the bending stress, thereby weakening the transmission of the bending stress of the housing connection part to the fixed connection point between the current collecting body and the tab, and improving the problem of poor welding between the current collecting member and the tab due to the bending stress.

[0008] In one example of the secondary battery of the present invention, the thickness of the current collecting body is a, the height that the buffer portion protrudes from the current collecting body is b, and 0.5a≦b≦3a.

[0009] In the above-mentioned technical solution, by setting the height of the buffer portion protruding from the current collecting body to 0.5a or more, it is possible to achieve that the buffer portion has space to deform, and by setting it to 3a or less, it is possible to avoid the buffer portion being too high and interfering with the bending of the housing connection portion, and it is also beneficial to saving materials.

[0010] In one example of the secondary battery of the present invention, the distance from the inside of the arch-shaped projection to the outer periphery of the current collecting member along the radial direction of the current collecting member is c, where b≦c≦4 mm.

[0011] In the above-mentioned technical solution, by setting b to be equal to or less than c, it is possible to achieve a sufficient space between the housing connection part and the current collecting body to accommodate the buffer part, and by setting the distance c from the inside of the arch-shaped protrusion to the outer edge of the current collecting member to be equal to or less than 4 mm, it is possible to make the buffer part and the housing connection part relatively close to each other, which is more helpful in absorbing bending stress and can reduce the transmission of bending stress from the housing connection part to the fixed connection point between the current collecting body and the tab.

[0012] In one example of the secondary battery of the present invention, the buffer section is provided with a first weakened section extending along the circumferential direction of the current collecting member, and the first weakened section is configured to weaken the strength of the buffer section.

[0013] In the above-mentioned technical solution, the installation of the first weak part helps to weaken the strength of the buffer part and further helps to deform the buffer part, thereby reducing the transmission of bending stress at the housing connection part to the fixed connection point between the current collecting body and the tab.

[0014] In one example of the secondary battery of the present invention, the current collecting member includes a plurality of housing connection portions and a plurality of buffer portions connected in a one-to-one correspondence with each housing connection portion. The plurality of buffer portions are connected to the outer periphery of the current collecting body so as to surround the periphery. The housing connection portions include a bent portion connected to the buffer portions. Notches are provided on both sides of the bent portion and / or the buffer portions along the circumferential direction of the housing.

[0015] In the above technical solution, the multiple housing connections are separated from the outer periphery surrounding the current collecting body. Their relatively high structural strength and relatively large contact area enhance heat dissipation and lower electrical resistance, while also reducing material usage and stress concentration. Each housing connection is connected to a corresponding buffer section, which absorbs bending stress at the corresponding housing connection section, improving the uniformity and balance of the force exerted on the current collecting member and thereby improving the stability of the current collecting member's conductivity. The inclusion of notches reduces the width of the bending section and / or buffer section. This reduces the strength of the bending section and / or buffer section to facilitate deformation, helping to absorb bending stress. In addition, the notches in the bending section reduce bending stress generated when the housing connection section is bent. The combination of these effects reduces the transmission of bending stress to the connection between the current collecting member and the tab, thereby alleviating the problem of poor welding between the current collecting member and the tab due to bending stress.

[0016] In one example of the secondary battery of the present invention, the sum of the minimum current-carrying areas of all the bent portions is s1, the sum of the minimum current-carrying areas of all the buffer portions is s2, and the total area of ​​the weld line formed by welding the current collector body and the tab is s, where s1>s and s2>s.

[0017] In the above technical solutions, the minimum current-carrying area of ​​the bent portion is the smallest point of the cross-sectional area of ​​each bent portion along the circumferential direction of the current collecting member. The minimum current-carrying area of ​​the buffer portion is the smallest point of the cross-sectional area of ​​each buffer portion along the circumferential direction of the current collecting member. The total area of ​​the weld lines refers to the area of ​​all the weld lines formed by the welding between the tab connection portions and the tabs, projected along the axial direction of the electrode member. A configuration in which the sum s1 of the minimum current-carrying areas of all the bent portions and the sum s2 of the minimum current-carrying areas of all the buffer portions are equally larger than the total weld line area s can reduce the transmission of bending stress without affecting the current-carrying effect of the bent portions and the buffer portions.

[0018] In one example of the secondary battery of the present invention, the housing connection portion includes a bent portion connected to the buffer portion. The bent portion is provided with a second weakened portion extending along the circumferential direction of the current collecting member. The second weakened portion is configured to weaken the strength of the bent portion.

[0019] In the above technical solution, providing a second weak portion at the bend reduces stress generated when the housing connection portion is bent. Because the second weak portion has low strength, it deforms first under stress, reducing the stress transmission to the welded portion between the current collecting member and the tab. This alleviates the problem of poor welding between the current collecting member and the tab due to bending stress. The second weak portion can also guide and position the bend of the bend, improving the accuracy of the bend position and helping to improve the consistency of the assembly quality of secondary batteries. Furthermore, when welding the housing connection portion to the housing before roll grooving, the second weak portion can serve as a reference line for the welding position, facilitating the positioning of the welding head during welding.

[0020] In one example of the secondary battery of the present invention, the sum of the minimum current-carrying areas of all the second weak parts is s3, the total area of ​​the weld line formed by welding the current collector body and the tab is s, and s3>s.

[0021] In the above-mentioned technical solution, the minimum current-carrying area of ​​each second weak part is the smallest point of the cross-sectional area of ​​each second weak part along the circumferential direction of the current collecting member. The sum s3 of the minimum current-carrying areas of all the second weak parts is greater than the total area s of the weld lines, which can weaken the transmission of bending stress without affecting the current-carrying effect of the second weak parts.

[0022] The present invention further provides an electronic device, which includes an electrode member, and a battery assembly including any one of the secondary batteries described above. [Effects of the Invention]

[0023] The secondary battery of the present invention has a buffer section provided between the housing connection section and the current collector body. The buffer section absorbs bending stress that occurs when the housing connection section is bent, weakening the transmission of bending stress from the housing connection section to the fixed connection point between the current collector body and the tab, thereby alleviating the problem of poor welding between the current collector member and the tab due to bending stress. [Brief explanation of the drawings]

[0024] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. The drawings described below are only some embodiments of the present invention, and it is obvious that those skilled in the art can obtain other embodiments based on these drawings without expending creative efforts.

[0025] [Figure 1] 1 is a diagram showing the overall structure of an example of a secondary battery of the present invention. [Figure 2] 1 is a structural diagram of an electrode member of an example of a secondary battery of the present invention. [Figure 3] 1 is a structural diagram of a current collecting member of a secondary battery according to a first embodiment of the present invention before being bent. [Figure 4] FIG. 4 is a partial enlarged view of a portion A in FIG. 3. [Figure 5] FIG. 4 is a front view of the current collecting member of FIG. [Figure 6] FIG. 6 is a partial enlarged view of a portion B in FIG. 5. [Figure 7] FIG. 10 is a structural diagram of a current collecting member of a secondary battery according to a second embodiment of the present invention before being bent. [Figure 8] FIG. 8 is a partial enlarged view of a portion C in FIG. 7. [Figure 9] FIG. 10 is a structural view of a current collecting member of a secondary battery according to a third embodiment of the present invention before being bent. [Figure 10] FIG. 10 is a partial enlarged view of a portion D in FIG. 9. [Figure 11] FIG. 10 is a structural view of a current collecting member of a secondary battery according to a fourth embodiment of the present invention before being bent. [Figure 12] FIG. 12 is a partial enlarged view of a portion E in FIG. [Figure 13] FIG. 12 is a front view of the current collecting member of FIG. [Figure 14] FIG. 14 is a partial enlarged view of a portion F in FIG. [Figure 15] FIG. 10 is a structural view of a current collecting member of a secondary battery according to a fifth embodiment of the present invention before being bent. [Figure 16]FIG. 16 is a partial enlarged view of a portion G in FIG. [Figure 17] FIG. 10 is a structural view of a current collecting member of a sixth embodiment of a secondary battery of the present invention before bending. [Figure 18] FIG. 18 is a partial enlarged view of a portion H in FIG. [Figure 19] 1 is a schematic diagram of an example of a battery pack in an electronic device of the present invention. [Figure 20] 1 is a schematic diagram of an example of an electronic device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The following describes how the present invention is implemented through specific embodiments. 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 may be implemented or applied in other different specific embodiments. Various changes and modifications may be made to the details of this specification based on different perspectives and applications without departing from the spirit of the present invention. The following embodiments and their features may be combined with each other unless inconsistent. It should also be understood that the terms used in the embodiments of the present invention do not limit the scope of protection of the present invention but are intended to describe specific embodiments. Test methods without specifying specific conditions in the following embodiments are usually based on general conditions or conditions recommended by manufacturers.

[0027] When an embodiment provides a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected unless otherwise specified in the present invention. Unless otherwise defined, all technical and scientific terms used in the present invention are consistent with the understanding of the prior art by those skilled in the art and the description of the present invention. The present invention can also be achieved by combining any methods, equipment, and materials in the prior art that are similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention.

[0028] The terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are used for the convenience of explanation and do not limit the scope of the present invention. Changing or adjusting the relative relationships between these terms is also considered to be within the scope of the present invention, provided that the technical content is not substantially changed.

[0029] A secondary battery includes an electrode member, which is a member where an electrochemical reaction occurs in the secondary battery, and may include one or more electrode members.

[0030] The secondary battery further includes a housing, a cap plate, and a terminal. The housing includes an end wall and a side wall surrounding the end wall. One end of the side wall has an opening, and the electrode member is assembled inside the housing through the opening. The cap plate is used to cover and seal the opening of the housing. The terminal penetrates the end wall and is electrically connected to the electrode member, thereby conducting electrical energy generated by the electrode member.

[0031] Mechanical seals are the mainstream packaging method for existing secondary batteries. Mechanical seals are widely used due to the advantages of mature technology and equipment, as well as a fast production cycle. The current collecting member is simultaneously electrically connected to the electrode member and the housing, achieving electrical connection between the electrode member and the housing. Specifically, a roll groove recessed into the side wall of the housing is first roll-pressed into the housing, and the side of the roll groove closest to the electrode member presses against the edge of the current collecting member. The roll groove can limit axial displacement of the electrode member. A cap plate is attached to a step formed on the side of the roll groove farther from the electrode member, and a seal member is provided between the cap plate and the housing. The edge of the opening is then upset to press the cap plate against the seal member, forming a reliable connection and sealing the housing.

[0032] There are several methods for connecting the electrode member and the housing, and one common method is to provide a housing connection part on the edge of the current collecting member, first weld the housing connection part to the side wall of the housing, and then roll press a roll groove into the side wall to bend the housing connection part toward the axis of the housing. However, the inventor discovered that when the housing connection part bends toward the axis of the housing, bending stress is generated, and this bending stress may be further transmitted to the inside of the current collecting member, causing the inside of the current collecting member to lift up and peeling off the welded part between the current collecting member and the electrode tab, posing a risk of poor electrical connection of the electrode member.

[0033] In view of this, the present invention provides a technical solution in which a buffer is provided between the housing connection part and the current collecting body, which can absorb the bending stress generated when the housing connection part is bent, reduce the transmission of the bending stress at the housing connection part to the fixed connection part between the current collecting body and the tab, and alleviate the problem of poor welding between the current collecting member and the tab due to the bending stress.

[0034] 1 to 20, the present invention provides a secondary battery 100. The secondary battery 100 includes a housing 110, an electrode member 120, a terminal 140, a cap plate 130, and a current collecting member 150.

[0035] Referring to FIG. 1 , the housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The connection between the end wall 111 and the side wall 112 may be realized by a variety of methods, such as integral stamping, integral casting, or split welding, as long as a stable sealing and electrical connection can be formed. The enclosure formed by the side wall 112 is not limited to a cylindrical or prismatic enclosure, and may have any other closed loop shape that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111. A circular opening 113 is formed at one end of the side wall 112 opposite the end wall 111. A housing cavity is formed within the housing 110, surrounded by the end wall 111 and the side wall 112, to accommodate the electrode member 120, electrolyte, and other components required for the battery. Specifically, the diameter size of the housing 110 may be determined depending on the specific size of the electrode member 120, and may be, for example, 18 mm, 21 mm, 46 mm, etc. The material of the housing 110 may be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. To prevent the housing 110 from rusting during long-term use, the surface of the housing 110 may be plated with a layer of an anti-rust material, such as metallic nickel.

[0036] 1 and 2, the electrode member 120 is housed in the housing 110. The electrode member 120 is a component where an electrochemical reaction occurs in the secondary battery 100. One or more electrode members 120 may be included in the housing 110. The electrode member 120 includes a wound structure formed by winding an electrode sheet and a separator 122. Specifically, in this embodiment, the electrode member 120 includes a positive electrode sheet 121, a separator 122, and a negative electrode sheet 123, which are wound around the axial direction of the housing 110.

[0037] 1 and 2, the positive electrode sheet 121 includes a positive electrode current collector 1211 and a positive electrode active material layer coated on the positive electrode current collector 1211. A first coated region 1212 coated with the positive electrode active material layer and a first uncoated region 1213 not coated with the positive electrode active material layer are formed on the positive electrode current collector 1211, and the first coated region 1212 and the first uncoated region 1213 are arranged along the axial direction of the casing 110. One end of the first uncoated region 1213 facing the height direction of the secondary battery 100 extends outside the separator 122 and is bent toward the axial line of the casing 110 to form a stacked positive electrode tab 125.

[0038] 1 and 2, the negative electrode sheet 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231. A second coated region 1232 coated with the negative electrode active material layer and a second uncoated region 1233 not coated with the negative electrode active material layer are formed on the negative electrode current collector 1231, and the second coated region 1232 and the second uncoated region 1233 are arranged along the axial direction of the casing 110. The other end of the second uncoated region 1233 facing in the height direction of the secondary battery 100 extends outside the separator 122 and is bent toward the axial line of the casing 110 to form a stacked negative electrode tab 124.

[0039] 1 and 2, the separator 122 is disposed between the positive electrode sheet 121 and the negative electrode sheet 123 to separate the positive electrode active material layer from the negative electrode active material layer. Taking the lithium-ion secondary battery 100 as an example, the positive electrode current collector 1211 may be made of aluminum, the positive electrode active material layer includes a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector 1231 may be made of copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The base material of the separator 122 may be polypropylene (PP), polyethylene (PE), etc. To provide the cell with protection and insulation functions, the outside of the cell may be further covered with an insulating film, which may be composed of PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0040] 1 and 2, the positive electrode tab 125 in the present invention faces the end wall 111 or the opening 113, and the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the terminal 140, causing the terminal 140 to be positively charged. The negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, causing the housing 110 to be negatively charged. However, in other embodiments, the negative electrode tab 124 may be connected to the terminal 140, and the positive electrode tab 125 may be connected to the housing 110.

[0041] Referring to FIG. 1 , the cap plate 130 is attached to seal the opening 113. The outer edge shape of the cap plate 130 corresponds to the shape of the opening 113 and connects with the side wall 112 to seal the opening 113. In a specific embodiment, a roll groove 114 recessed into the housing 110 is roll-pressed in an area near the outer edge of the side wall 112 of the housing 110. The roll groove 114 includes a first side wall 1141 and a second side wall 1142. The first side wall 1141 is close to the electrode member 120 and can limit the axial displacement of the electrode member 120. The side of the second side wall 1142 far from the roll groove 114 surrounds the housing 110 to form an annular step, and the cap plate 130 is disposed on the step. A seal ring is provided between the cap plate 130 and the roll groove 114. The edges of the opening 113 are upset to compress the cap plate 130 against the seal ring, forming a reliable connection.

[0042] 1 and 2 , the terminal 140 is fixed to the end wall 111 and electrically connected to the electrode member 120. Specifically, a terminal hole is provided in the end wall 111, and the terminal 140 is attached by penetrating the terminal hole and is insulated from the end wall 111. One end of the terminal 140 facing the electrode member 120 penetrates the end wall 111 and is electrically connected directly or indirectly to the positive electrode tab 125. The structure of the terminal 140 may be any suitable shape that can penetrate the end wall 111 and electrically connect to the positive electrode tab 125 of the electrode member 120. For example, the cross section may be circular, square, prismatic, or a specially shaped profile that can achieve stable electrical conduction, and the shapes of the terminal hole and the terminal 140 correspond to each other. In this embodiment, the cross section of the terminal 140 is circular.

[0043] 1 , the current collecting member 150 is provided between the electrode member 120 and the cap plate 130. The housing 110 and the electrode member 120 are electrically connected by the current collecting member 150. Specifically, the current collecting member 150 includes a current collecting body 151 and a housing connection portion 152 that connects to the outer periphery of the current collecting body 151. The housing connection portion 152 may have an overall annular structure or one or more fan-shaped portions, as long as it satisfies the electrical conductivity requirements and welding strength requirements between the current collecting member 150 and the housing 110. Before the roll groove 114 is roll-pressed into the housing 110, the housing connection portion 152 is first welded to the side wall 112 of the housing 110, and while the roll groove 114 is being roll-pressed, the housing connection portion 152 welded to the housing 110 continues to bend toward the axis of the housing 110, and finally bends toward the axis of the housing 110 to form a welded structure with the surface of the roll groove 114 facing the electrode member 120.

[0044] Referring to Figures 3, 7, 9, 11, 15, and 17, the current collecting body 151 is fixedly connected to the tab. There are several ways to connect the current collecting body 151 and the tab, such as welding or conductive adhesive bonding, as long as they can achieve electrical connection between the current collecting member 150 and the tab and satisfy electrical conductivity requirements. In this embodiment, welding is used. Furthermore, the portion where the current collecting body 151 is welded to the tab is a tab connection portion 154. The shape and position of the tab connection portion 154 are not limited. In this embodiment, it is preferable that four tab connection portions 154 are formed on the current collecting body 151 by welding to the tab. The four tab connection portions 154 are evenly spaced around the circumferential direction of the current collecting body 151. This configuration provides better welding balance stability between the current collecting body 151 and the tab and more uniform electrical conductivity, thereby improving electrical conductivity stability between the housing 110 and the electrode member 120.

[0045] Considering the problem that bending stress occurs when housing connection portion 152 bends toward the axis of housing 110 and that this bending stress may be further transmitted to the inside of current collecting member 150, causing the inside of current collecting member 150 to lift up, with reference to FIGS. 3 to 18 , current collecting member 150 further includes buffer portion 153 that connects housing connection portion 152 and current collecting body 151. Buffer portion 153 may have a variety of forms, including, but not limited to, an easily deformable elastic structure or elastic material, as long as it can absorb the bending stress when housing connection portion 152 is bent. Buffer portion 153 can reduce the transmission of bending stress from housing connection portion 152 to the fixed connection point between current collecting body 151 and the tab, thereby improving the problem of poor welding between current collecting member 150 and the tab due to bending stress.

[0046] 3 to 18 , in one example of the secondary battery 100 of the present invention, the buffer portion 153 includes an arch-shaped protrusion protruding from the current collecting body 151 and extending circumferentially around the outer periphery of the current collecting body 151. The side of the buffer portion 153 facing the arch-shaped protrusion is formed as a recess. When bending stress generated by bending the housing connection portion 152 is transmitted to the current collecting body 151, the buffer portion 153 is stretched and deformed to straighten, partially absorbing the bending stress. This reduces the transmission of the bending stress of the housing connection portion 152 to the fixed connection point between the current collecting body 151 and the tab, thereby alleviating the problem of poor welding between the current collecting member 150 and the tab due to bending stress. The direction of the arch-shaped protrusion is not limited, and it may protrude toward the cap plate 130 or toward the electrode member 120. In this embodiment, the arch-shaped protrusion preferably protrudes toward the cap plate 130. This configuration does not occupy axial space in the housing 110, and the larger storage space of the housing 110 helps to improve energy density.

[0047] 3 to 6, in one example of secondary battery 100 of the present invention, current collecting body 151 has a thickness a, and buffer portion 153 protrudes from current collecting body 151 to a height b, where 0.5a≦b≦3a. For example, b may be 0.5a, 0.75a, a, 1.25a, ​​1.5a, 1.75a, 2a, 2.5a, or 3a. Setting the height of buffer portion 153 protruding from current collecting body 151 to 0.5a or more ensures that buffer portion 153 has space to deform. Setting the height to 3a or less prevents buffer portion 153 from being excessively high and interfering with the bending of housing connection portion 152, and also contributes to saving materials.

[0048] 3 to 6, in one example of the secondary battery 100 of the present invention, the distance c from the inner side of the arch-shaped protrusion to the outer periphery of the current collecting member 150 along the radial direction of the current collecting member 150 satisfies the condition b≦c≦4 mm. By setting b equal to or less than c, it is possible to provide a sufficient space between the housing connection portion 152 and the current collecting body 151 to accommodate the buffer portion 153. Setting the distance c from the inner side of the arch-shaped protrusion to the outer periphery of the current collecting member to be equal to or less than 4 mm may be, for example, 4 mm, 3.5 mm, 3 mm, 2.5 mm, 2 mm, 1.5 mm, or 1 mm, as long as it is equal to or greater than b. The value of b may be appropriately adjusted according to the actual situation. This configuration allows the buffer portion 153 and the housing connection portion 152 to be relatively close to each other, which further helps absorb bending stress and reduces the transmission of bending stress from the housing connection portion 152 to the fixed connection point between the current collecting body 151 and the tab.

[0049] 11 to 18, in one example of secondary battery 100 of the present invention, first weakened portions 1531 extending along the circumferential direction of current collecting member 150 are provided on buffer portion 153. First weakened portions 1531 may have a variety of forms, for example, a combination of one or more of thinning, notching, and hollowing, as long as they can weaken the strength of buffer portion 153 and make buffer portion 153 easier to deform. This reduces the transmission of bending stress from housing connection portion 152 to the fixed connection point between current collecting body 151 and the tab.

[0050] 3 to 18 , in one example of a secondary battery 100 according to the present invention, a current collecting member 150 includes a plurality of housing connectors 152 and a plurality of buffers 153 connected to the housing connectors 152 in a one-to-one correspondence. The buffers 153 are connected to surround the outer periphery of the current collecting body 150. This configuration provides relatively high structural strength and a relatively large contact area, thereby improving heat dissipation and lowering electrical resistance, while also reducing material usage and stress concentration. Furthermore, for convenient positioning and connection between the housing connectors 152 and the current collecting member 150, in this embodiment, the housing connectors 152 have the same shape and are arranged along the circumferential direction of the current collecting body 150. This configuration can produce a more uniform electrical conductivity between the current collecting member 150 and the sidewall 112 in the circumferential direction, thereby improving the stability of electrical conductivity between the housing 110 and the electrode member 120. Furthermore, each housing connection portion 152 is connected to a buffer portion 153 in a one-to-one correspondence, and each buffer portion 153 can have the effect of absorbing bending stress on the corresponding housing connection portion 152, thereby improving the uniformity and balance of the force received by the collecting member 150 and thereby improving the stability of the conductivity of the collecting member 150.

[0051] 7 to 18 , in one example of the secondary battery 100 of the present invention, the housing connection portion 152 includes a bending portion 1521 connected to the buffer portion 153. Notches 1522 are provided on both sides of the bending portion 1521 and / or the buffer portion 153 along the circumferential direction of the housing 110. This configuration may include openings 113 provided only on both sides of the bending portion 1521 or notches 1522 provided only on both sides of the buffer portion 153. In addition, notches 1522 may be provided on both ends of the bending portion 1521 and the buffer portion 153. The provision of the notches 1522 reduces the width of the bending portion 1521 and / or the buffer portion 153, thereby reducing the strength of the bending portion 1521 and / or the buffer portion 153 to facilitate deformation and help absorb bending stress. Furthermore, the notches 1522 in the bending portion 1521 can reduce bending stress generated when the housing connection portion 152 is bent. The combination of the above effects can weaken the transmission of bending stress to the welded portion between the current collecting member 150 and the tab, thereby alleviating the problem of poor welding between the current collecting member 150 and the tab due to bending stress.

[0052] 3 to 18, in one example of secondary battery 100 of the present invention, the sum of the minimum current-carrying areas of all bent portions 1521 is s1, the sum of the minimum current-carrying areas of all buffer portions 153 is s2, and the total area of ​​the weld line formed by welding current collecting body 151 to the tab is s, where s1 > s and s2 > s. It should be noted that the minimum current-carrying area of ​​bent portions 1521 is the smallest point in the cross-sectional area of ​​each bent portion 1521 along the circumferential direction of current collecting member 150. The minimum current-carrying area of ​​buffer portions 153 is the smallest point in the cross-sectional area of ​​each buffer portion 153 along the circumferential direction of current collecting member 150. The total area of ​​the weld line refers to the area of ​​all the weld lines formed by welding current collecting body 151 to the tab projected along the axial direction of electrode member 120. A configuration in which the sum s1 of the minimum current-carrying areas of all bending sections 1521 and the sum s2 of the minimum current-carrying areas of all buffer sections 153 are equally larger than the total welding line area s can weaken the transmission of bending stress while not affecting the current-carrying effect of bending sections 1521 and buffer sections 153.

[0053] 3 to 18 , in one example of secondary battery 100 of the present invention, housing connection portion 152 includes bent portion 1521 connected to buffer portion 153. Bent portion 1521 is provided with second weakened portion 1523 extending along the circumferential direction of current collecting member 150. Second weakened portion 1523 may have multiple forms, such as a combination of one or more of thinning, notching, and hollowing, as long as it weakens the strength of buffer portion 153 and makes buffer portion 153 more easily deformable. Providing second weakened portion 1523 in bent portion 1521 can weaken the stress generated when housing connection portion 152 is bent. At the same time, because second weakened portion 1523 has low strength, second weakened portion 1523 of bent portion 1521 is primarily deformed under the action of stress, thereby reducing the transmission of stress to the welded portion between current collecting member 150 and the tab. This alleviates the problem of poor welding between the current collecting member 150 and the tab due to bending stress, and the second weakened portion 1523 can also guide and position the bending of the bending portion 1521, improving the accuracy of the bending position of the bending portion 1521 and helping to improve the consistency of the assembly quality of the secondary battery 100. In addition, when welding the housing connection portion 152 and the housing 110 before roll grooving 114, the second weakened portion 1523 can also serve as a reference line for the welding position, which is convenient for positioning the welding head during welding.

[0054] 3 to 18, in one example of secondary battery 100 of the present invention, second weak portions 1523 have a minimum current-carrying area s3, and the total area of ​​the weld lines formed by welding current collecting body 151 to the tab is s, where s3 > s. It should be noted that the minimum current-carrying area of ​​second weak portions 1523 is the smallest point in the cross-sectional area of ​​each second weak portion 1523 along the circumferential direction of current collecting member 150. A configuration in which the sum s3 of the minimum current-carrying areas of all second weak portions 1523 is larger than the total area s of the weld lines can weaken the transmission of bending stress without affecting the flow effect of second weak portions 1523.

[0055] 3 to 6, in one embodiment of the secondary battery 100 of the present invention, the outer periphery of the current collecting body 151 is surrounded by four housing connectors 152. A buffer section 153 is provided between each housing connector 152 and the current collecting body 151. The buffer section 153 is an arch-shaped protrusion that protrudes toward the cap plate 130. The thickness a of the current collecting body 151 is 0.2 mm. The height b of the buffer section 153 that protrudes from the current collecting body 151 is 0.4 mm. The distance c from the inside of the arch-shaped protrusion to the outer periphery of the current collecting member 150 is 3.5 mm. The bent section 1521 is provided with a second weakened section 1523 that reduces the strength of the bent section 1521. The second weakened section 1523 has a thin structure. The configuration of this thin structure reduces the stress generated when the housing connection portion 152 is bent, while at the same time weakening the strength of the bending portion 1521. When stress is applied, the second weak portion 1523 of the bending portion 1521 deforms first, thereby weakening the transmission of stress to the welding portion between the current collecting member 150 and the tab, thereby improving the problem of poor welding between the current collecting member 150 and the tab due to bending stress.

[0056] 7 and 8, a second embodiment of a secondary battery 100 according to the present invention differs from the first embodiment in that notches 1522 are provided at both ends of a bent portion 1521 to reduce the strength of the bent portion 1521. The provision of the notches 1522 reduces the width of the bent portion 1521, further reducing the strength of the bent portion 1521 to facilitate deformation and helping to absorb bending stress. In addition, the notches 1522 in the bent portion 1521 can reduce the bending stress generated when the housing connection portion 152 is bent. The combination of the above effects can reduce the transmission of bending stress to the welded portion between the current collecting member 150 and the tab, thereby alleviating the problem of poor welding between the current collecting member 150 and the tab due to bending stress.

[0057] 9 and 10, a third embodiment of a secondary battery 100 according to the present invention differs from the first embodiment in that notches 1522 are provided at both ends of the buffer portion 153 to reduce the strength of the buffer portion 153. The provision of the notches 1522 reduces the width of the buffer portion 153, further reducing the strength of the buffer portion 153 to facilitate deformation and helping to absorb bending stress. This reduces the transmission of bending stress to the welded portion between the current collecting member 150 and the tab, thereby alleviating the problem of poor welding between the current collecting member 150 and the tab due to bending stress.

[0058] 11 to 14, a fourth embodiment of a secondary battery 100 of the present invention differs from the second embodiment in that a first weak portion 1531 is provided in a buffer portion 153. The first weak portion 1531 has a thin structure. This thin structure can weaken the strength of the buffer portion 153 and is favorable for deformation of the buffer portion 153, thereby weakening the transmission of bending stress of the housing connection portion 152 to the fixed connection portion between the current collector body 151 and the tab.

[0059] 15 and 16 , in a fifth embodiment of the secondary battery 100 of the present invention, the outer periphery of the current collecting body 151 is surrounded by four housing connectors 152. A buffer section 153 is provided between each housing connector 152 and the current collecting body 151. The buffer section 153 is an arch-shaped protrusion that protrudes toward the cap plate 130. The thickness a of the current collecting body 151 is 0.2 mm. The height b of the buffer section 153 that protrudes from the current collecting body 151 is 0.4 mm. The distance c from the inside of the arch-shaped protrusion to the outer periphery of the current collecting member 150 is 3.5 mm. The buffer section 153 is provided with a first weak section 1531. The first weak section 1531 has a hollowed-out structure. That is, a plurality of through holes are provided along the circumferential direction of the buffer section 153. The shape of the through holes may be, but is not limited to, a circular hole, an elliptical hole, an oblong hole, or the like. In this embodiment, the bent portion 1521 is a circular hole. Furthermore, notches 1522 are provided at both ends of the bent portion 1521 to reduce the strength of the bent portion 1521. Second weakened portions 1523 may also be provided to further reduce the strength of the bent portion 1521. The second weakened portions 1523 have a thinned structure. The combined effect of the first weakened portions 1531, the second weakened portions 1523, and the notches 1522 has the effect of further effectively reducing the transmission of bending stress to the welded portion between the current collecting member 150 and the tab, thereby alleviating the problem of poor welding between the current collecting member 150 and the tab due to bending stress.

[0060] 17 and 18, in a sixth embodiment of the secondary battery 100 of the present invention, the through-hole has an elongated shape. The elongated hole has a larger cutout area formed in the buffer portion 153, which has the effect of weakening the strength of the buffer portion 153 more preferably.

[0061] Referring to FIG. 20 , the present invention further provides an electronic device 1. The electronic device 1 includes a battery assembly 10. The battery assembly 10 includes a secondary battery 100 according to any one of the above-described embodiments. In one embodiment of the battery assembly 10 of the present invention, referring to FIG. 19 , the battery assembly 10 includes a case 101, a case lid 102, and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are disposed within the case 101 and connected in series or parallel to one another, or a combination of series and parallel. The case lid 102 covers the case 101 to protect the plurality of secondary batteries 100. It should be noted that the battery assembly 10 may include components such as a thermal management system for the battery assembly 10, a circuit board, etc., in addition to the secondary battery 100 of the present invention. The battery assembly 10 may be a battery module, a battery pack, an energy storage cabinet, etc., each of which will not be described here.

[0062] The electronic device 1 further includes an operating unit 11. The operating unit 11 is electrically connected to the battery assembly 10 to obtain power support. As an example, the electronic device 1 is a vehicle, which may be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle may be, but is not limited to, a pure electric vehicle, a hybrid vehicle, or a range-extending vehicle. The operating unit 11 is a vehicle body, and the battery assembly 10 is installed at the bottom of the body and provides power support for running the vehicle or operating electrical components inside the vehicle. However, in some other embodiments, the electronic device 10 may be a mobile phone, a portable device, a notebook computer, a boat, an airplane, an electric toy, an electric tool, or the like. Aircraft include airplanes, rockets, space shuttles, spacecraft, and the like. The operating unit 11 may be a unit that obtains electrical energy from the battery assembly 10 and performs a corresponding operation, such as a blade rotation unit of an electric fan or a dust collection unit of a vacuum cleaner. The electric toys include stationary or mobile electric toys, such as game consoles, electric toy cars, electric toy boats, electric toy airplanes, etc. The electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, electric planes, etc. The embodiments of the present invention are not particularly limited to the electronic device 1 described above.

[0063] The secondary battery of the present invention includes a buffer between the housing connection and the current collecting body. The buffer absorbs bending stress generated when the housing connection is bent, reducing the transmission of bending stress from the housing connection to the fixed connection between the current collecting body and the tab, thereby improving the problem of poor welding between the current collecting member and the tab due to bending stress. Therefore, the present invention effectively overcomes several practical problems in the prior art and has high utility and practical significance. The above-described embodiments are intended to illustrate the principles and effects of the present invention and are not intended to limit the present invention. Those skilled in the art may modify or alter the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed by the present invention are still intended to be protected by the claims of the present invention. [Industrial Applicability]

[0064] The secondary battery of the present invention has a buffer section provided between the housing connection section and the current collector body. The buffer section absorbs bending stress that occurs when the housing connection section is bent, weakening the transmission of bending stress from the housing connection section to the fixed connection point between the current collector body and the tab, thereby alleviating the problem of poor welding between the current collector member and the tab due to bending stress. [Explanation of symbols]

[0065] 1:Electronic equipment 10:Battery assembly 11: Operating unit 101: Box body 102: Box lid 100: Secondary battery 110: Cabinet 111: End wall 112: Side wall 113:Aperture 114: Roll Groove 1141: First side wall 1142: Second side wall 120: Electrode member 121: Positive electrode sheet 1211: Positive electrode current collector 1212: 1st application area 1213: 1st non-coating area 122: Separator 123: Negative electrode sheet 1231: Negative electrode current collector 1232:Second application area 1233: 2nd non-coating area 124: Negative electrode tab 125: Positive electrode tab 130: Cap plate 140: Terminal 150: Current collecting member 151: Current collector body 152: Housing connection part 1521: Bend 1522: Notch 1523: Second vulnerable part 153:Buffer section 1531: First weak spot 154: Tab connection

Claims

1. a housing including a side wall surrounding the periphery, an opening formed in one end of the side wall, and an end of the side wall near the opening including a roll groove recessed toward the inside of the housing; an electrode member housed within the housing and including a tab facing the opening; a cap plate attached to seal the opening; a current collecting member including a current collecting body fixedly connected to the tab, and a housing connection portion provided on an outer peripheral edge of the current collecting body, bent toward an axis of the housing, and welded to a surface of the roll groove facing the electrode member; Including, The current collecting member further includes a buffer portion that connects the housing connection portion and the current collecting body, and the buffer portion is configured to be able to absorb bending stress when the housing connection portion is bent. characterized in that Secondary battery.

2. The buffer portion includes an arch-shaped protrusion that protrudes from the current collecting body and extends along the circumferential direction of the outer periphery of the current collecting body, and the buffer portion has a recess formed on the side facing the arch-shaped protrusion. characterized in that The secondary battery according to claim 1 .

3. The thickness of the current collecting body is a, the height of the buffer portion protruding from the current collecting body is b, and 0.5a≦b≦3a characterized in that The secondary battery according to claim 2 .

4. The distance from the inside of the arch-shaped protrusion to the outer circumferential edge of the current collecting member along the radial direction of the current collecting member is c, and b≦c≦4 mm. characterized in that The secondary battery according to claim 3 .

5. The buffer portion is provided with a first weakened portion extending along the circumferential direction of the current collecting member, and the first weakened portion is configured to weaken the strength of the buffer portion. characterized in that The secondary battery according to claim 2 .

6. the current collecting member includes a plurality of the housing connection portions and a plurality of the buffer portions connected in one-to-one correspondence with the housing connection portions, The plurality of buffer portions are connected to the outer periphery of the current collecting body so as to surround the periphery, The housing connection portion includes a bent portion connected to the buffer portion, and the bent portion and / or the buffer portion are provided with notches on both sides along the circumferential direction of the housing. characterized in that The secondary battery according to claim 1 .

7. The sum of the minimum current-carrying areas of all the bent portions is s1, the sum of the minimum current-carrying areas of all the buffer portions is s2, and the total area of ​​the weld line formed by welding the current collecting body and the tab is s, where s1>s and s2>s. characterized in that The secondary battery according to claim 6.

8. The housing connection portion includes a bent portion connected to the buffer portion, and the bent portion is provided with a second weakened portion extending along the circumferential direction of the current collecting member, and the second weakened portion is configured to weaken the strength of the bent portion. characterized in that The secondary battery according to claim 6.

9. The sum of the minimum current-carrying areas of all the second weak portions is s3, the total area of ​​the weld line formed by welding the current collecting body and the tab is s, and s3>s characterized in that The secondary battery according to claim 8.

10. A battery assembly including the secondary battery according to any one of claims 1 to 9. characterized in that electronic equipment.

Images