Collecting member, secondary battery, and electronic device

Abstract

The utility model provides a current collecting member, a secondary battery and an electronic device, the current collecting member is used for connecting a shell and an electrode assembly in the secondary battery, the current collecting member comprises a current collecting body and a plurality of pins, and the current collecting body is used for connecting the electrode assembly; the multiple pins are connected to the periphery of the current collecting body at intervals, each pin extends outwards from the current collecting body and is bent, and the pins are used for being connected with the shell; each pin is provided with at least one buffer hole, the buffer holes penetrate in the thickness direction of the pins and extend in the circumferential direction of the pins, and the technical problem that fixation between the current collecting component and the shell is prone to failure can be solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field, concretely relates to a current collection component, secondary battery and electronic device. BACKGROUND

[0002] Mechanical sealing is the mainstream packaging mode of the existing cylindrical battery, and is widely used because of its mature process and equipment and fast production rhythm. The existing cylindrical battery usually sets a current collection component at the position close to the opening of the shell, so that one end of the current collection component is welded to the side wall of the shell, and the other end is electrically connected with the tab of the electrode assembly, thereby realizing the electrical connection between the shell and the electrode assembly, and then mechanical sealing is carried out.

[0003] The mechanical sealing includes rolling a groove recessed towards the inside of the shell on the side wall of the shell, and then the cover plate is pressed tightly by the bump sealing mode. During the rolling process, the current collection component will be bent due to the deformation of the groove. Because of the bending stress, the fixation between the current collection component and the shell is prone to failure. SUMMARY

[0004] The utility model provides a kind of current collection component, secondary battery and electronic device to improve the technical problem that the fixation between current collection component and shell is prone to failure.

[0005] To achieve the above object and other related purposes, the utility model provides a kind of current collection component, secondary battery and electronic device, which is used for connecting the shell and the electrode assembly in the secondary battery, comprising: a current collection body and a plurality of pins, the current collection body is used for connecting the electrode assembly;A plurality of pins are connected to the outer periphery of the current collection body with intervals, each pin extends outward from the current collection body and is bent, and the pin is used for connecting the shell;At least one buffer hole is provided on each pin, the buffer hole penetrates along the thickness direction of the pin and extends along the circumferential direction of the pin.

[0006] In the above technical solution, the buffer hole is provided on the pin. During the mechanical sealing process, when the pin continues to bend towards the axis of the current collection body: on the one hand, the buffer hole plays a role in reducing the bending difficulty through local thinning effect. On the other hand, the buffer hole can absorb stress through plastic deformation. On the other hand, the stress isolation zone formed by the edge of the buffer hole blocks the stress conduction path. It can weaken the transmission of stress to the connection between the pin and the shell when the pin is bent, thereby reducing the risk of fracture of the current collection component at the connection with the shell, and improving the technical problem that the fixation between the current collection component and the shell is prone to failure.

[0007] In an example of the current collection component of the utility model, the pin includes a bending portion and a shell connecting portion connected in series, one end of the bending portion away from the shell connecting portion is connected with the current collection component, the shell connecting portion extends from the bending portion towards the direction away from the current collection body, the shell connecting portion is used for connecting the shell, and the buffer holes are all located in the shell connecting portion.

[0008] In the technical scheme, when the fixed connection mode of the pin and the shell is welding, due to the diffuse reflection of the laser on the pin, the reflected laser has the risk of burning the electrode assembly through the buffer hole, so the buffer hole is arranged on the shell connecting part to avoid the bending part. The arrangement makes the buffer hole and the electrode assembly not overlap, which can reduce the risk of the reflected laser irradiating the electrode assembly through the buffer hole, and further reduce the risk of the electrode assembly being burned.

[0009] In an example of the current collecting member, the hole wall profile of the buffer hole is a continuous smooth closed profile.

[0010] In the technical scheme, the hole wall profile of the buffer hole is a continuous smooth closed profile, which avoids the problem of stress concentration caused by sharp edges or corners, and can reduce the risk of the buffer hole being easily torn and damaged at the position of stress concentration.

[0011] In an example of the current collecting member, along the circumference of the current collecting member, the sum of the lengths of the buffer holes on each pin is L1, the length of the pin is L2, and L1≤0.8L2.

[0012] In the technical scheme, L1≤0.8L2 is limited. This is conducive to ensuring that the pin has sufficient strength, and further reducing the risk of fracture.

[0013] In an example of the current collecting member, along the direction in which the pin extends outward from the current collecting body, the length of the buffer hole is greater than 0.1mm.

[0014] In the technical scheme, the length of the buffer hole in the outward extending direction of the pin is limited to be greater than 0.1mm, which is conducive to the buffer hole having sufficient deformation space to ensure that the buffer hole has the ability to absorb stress and block stress transmission, so as to improve the technical problem of easy fixation failure between the current collecting member and the shell.

[0015] The utility model also provides a kind of secondary battery, and the secondary battery includes: shell, electrode assembly and current collecting member;Shell includes surrounding side wall, and the opening is formed in one end of side wall, and the end of shell close to opening includes the rolling groove recessed to shell interior;Electrode assembly is contained in shell, and electrode assembly includes tab facing opening;Current collecting member includes current collecting body and multiple interval connection pins on the outer periphery of current collecting body, and current collecting body is fixedly connected with tab, and pin is bent to the axis of shell, and is welded with the surface of rolling groove facing electrode assembly, and is formed with first welding mark, and at least one buffer hole is provided on each pin, and buffer hole penetrates along the thickness direction of pin, and extends along the circumference of pin;Along the circumference of pin, pin includes weakening portion provided with buffer hole, and first welding mark is located in weakening portion.

[0016] In the technical solution, the pin of the current collecting component is provided with a through buffer hole. During the mechanical sealing process, when the pin continues to be bent towards the axis of the current collecting body, on the one hand, the buffer hole reduces the bending difficulty through a local thinning effect. On the other hand, the buffer hole can absorb stress through plastic deformation. On the other hand, the stress isolation area formed by the edge of the buffer hole blocks the stress conduction path. The stress of the pin during bending can be weakened to the connection between the pin and the shell, thereby reducing the risk of fracture of the current collecting component at the connection with the shell and improving the technical problem of easy fixation failure between the current collecting component and the shell.

[0017] In addition, in the technical solution, the region of the pin provided with the buffer hole is weakened in structural strength, thereby forming a weakened part and limiting the first welding mark formed during the welding of the pin and the shell to be located in the weakened part. During the welding, the pulling force of the first welding mark on the pin can cause the buffer hole to deform, so that the pin is closer to the inner wall of the shell. In turn, the gap between the pin and the shell is reduced, and the risk of collapse of the molten pool of the first welding mark is reduced. The welding strength of the pin and the shell can be improved, which is beneficial to improve the technical problem of easy fixation failure between the current collecting component and the shell.

[0018] In the example of the secondary battery of the utility model, the minimum distance between the first welding mark and the edge of the buffer hole is greater than 1mm.

[0019] In the technical solution, the minimum distance between the first welding mark and the edge of the buffer hole is limited to be greater than 1mm. The risk of damaging the buffer hole during welding of the pin and the shell can be reduced.

[0020] In the example of the secondary battery of the utility model, the minimum distance between the first welding mark and the edge of the buffer hole is less than 2mm.

[0021] In the technical solution, since the current collecting body will be folded away from the electrode assembly from the middle during pressure relief of the secondary battery, the first welding mark is usually the fulcrum of the folding. Limiting the minimum distance between the first welding mark and the edge of the buffer hole to be less than 2mm can reduce the redundant length of the pin, which is beneficial to the root support during folding of the current collecting body and improves the safety performance of the secondary battery.

[0022] In the example of the secondary battery of the utility model, the buffer hole is located outside the electrode assembly along the radial direction of the current collecting component.

[0023] In the technical solution, the buffer hole is located outside the electrode assembly to prevent molten slag and the like generated during welding from falling onto the electrode assembly through the buffer hole, causing burns of the electrode assembly, and preventing damage to the electrode assembly by foreign matter.

[0024] In a secondary battery example of the utility model, the electrode assembly comprises a cladding layer cladded on the outermost side, and the cladding layer is higher than an end of the electrode assembly close to the current collecting member along the axial direction of the current collecting member.

[0025] In the above technical solution, a small amount of scattered laser light can be reflected into the inner wall of the shell through the buffer hole and then reflected onto the electrode assembly, causing the electrode assembly to be scalded. The outermost side of the electrode assembly is cladded with a cladding layer, and the cladding layer is higher than an end of the electrode assembly close to the current collecting member. The scattered laser light can be absorbed by the cladding layer to prevent damage to the electrode assembly.

[0026] The utility model also provides an electronic device, the electronic device includes battery group, and the battery group includes the secondary battery of any one of the above.

[0027] The utility model discloses a current collecting member, and a buffer hole is arranged through the pin. During the mechanical sealing process, when the pin continues to be bent towards the axial line of the current collecting body: on the one hand, the buffer hole plays the effect of reducing the bending difficulty through the local thinning effect. On the other hand, the buffer hole can realize the stress absorption effect through plastic deformation. On the other hand, the stress isolation area formed by the edge of the buffer hole blocks the stress conduction path. The stress transmission of the pin to the connection between the pin and the shell when being bent can be weakened, the risk of the current collecting member being broken at the connection with the shell is further reduced, and the technical problem of easy fixation failure between the current collecting member and the shell is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and other embodiments can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0029] Figure 1 It is a structure schematic view of the current collecting member example of the utility model;

[0030] Figure 2 It is a structure schematic view of the current collecting member example of the utility model;

[0031] Figure 3 It is a structure schematic view before mechanical sealing in a secondary battery example of the utility model;

[0032] Figure 4 It is Figure 3 It is a partial enlarged view of A in an example;

[0033] Figure 5 It is Figure 3 It is a partial enlarged view of A in an example;

[0034] Figure 6 For Figure 3 A local enlarged view at B in an example;

[0035] Figure 7 For a structure schematic view of a secondary battery of the utility model;

[0036] Figure 8 For a structure schematic view of an electrode assembly of a secondary battery of the utility model;

[0037] Figure 9 For Figure 8 A local enlarged view at B in an example;

[0038] Figure 10 For a schematic view of a battery pack in an example of the electronic device;

[0039] Figure 11 For a schematic view of an example of the electronic device.

[0040] Element number explanation:

[0041] 1, electronic device; 10, battery pack; 11, working part; 101, box body; 102, box cover; 100, secondary battery; 110, shell; 111, end wall; 112, side wall; 113, opening; 114, rolling groove; 120, electrode assembly; 121, first pole piece; 1211, negative current collector; 1212, first coating area; 1213, first non-coating area; 122, diaphragm; 123, second pole piece; 1231, positive current collector; 1232, second coating area; 1233, second non-coating area; 124, first pole lug; 125, second pole lug; 126, cladding layer; 130, current collecting member; 131, current collecting body; 132, pin; 1321, buffer hole; 1322, bending part; 1323, shell connecting part; 1324, first welding mark; 1325, weakened part; 140, cover plate; 150, pole column. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present application. The present application can also be implemented or applied through different specific embodiments, and the details in the present application can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present application are used to describe specific specific embodiments, but not to limit the protection scope of the present application. The test methods in the following embodiments are not specified, and are usually performed according to conventional conditions or conditions recommended by manufacturers.

[0043] When the embodiments give a numerical range, it should be understood that, unless otherwise stated by the present application, each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are used by those skilled in the art of the present technology and the description of the present application, and any method, device and material of the prior art similar or equivalent to the method, device and material in the embodiments of the present application can be used to implement the present application.

[0044] It should be understood that the terms such as "up", "down", "left", "right", "middle" and "one" in the present application are only for the convenience of clear description, and are not used to limit the scope of the present application. The change or adjustment of the relative relationship is also considered as the scope of the present application without substantial change of the technical content.

[0045] The secondary battery includes an electrode assembly, which is a component in which an electrochemical reaction occurs in the secondary battery, and can include one or more electrode assemblies.

[0046] The secondary battery further includes a case, a cover plate and a pole, the case includes an end wall and a side wall surrounding the end wall, one end of the side wall has an opening, the electrode assembly can be assembled into the case through the opening of the case, the cover plate is used to cover the opening of the case to achieve sealing, and the pole is electrically connected with the electrode assembly through the end wall to guide the electrical energy generated by the electrode assembly out.

[0047] The mainstream packaging mode of the existing secondary battery is mechanical sealing, which has the advantages of mature process and equipment and fast production rhythm, and is widely used. The current collecting member is electrically connected with the electrode assembly and the shell at the same time to realize the electrical connection between the electrode assembly and the shell. Specifically, a rolling groove recessed towards the inside of the shell is rolled on the side wall of the shell, the edge of the current collecting member is pressed against the side of the rolling groove close to the electrode assembly, the rolling groove can limit the axial displacement of the electrode assembly, the cover plate is installed on the step formed on the side of the rolling groove away from the electrode assembly, a sealing element is arranged between the cover plate and the shell, and the cover plate is pressed against the sealing element in a piling sealing mode to form reliable connection and realize the sealing of the shell.

[0048] There are various connection modes of the current collecting member and the shell, and a commonly used mode is that a pin is arranged on the edge of the current collecting member, the pin is first welded and fixed to the side wall of the shell, and then the rolling groove is rolled on the side wall to make the pin continue to bend towards the axis of the shell. However, the inventor finds that the pin has a large pulling force at the welding position of the pin and the side wall during the bending process, which causes the risk of breakage of the pin at the above-mentioned welding position. During the subsequent piling sealing process, the edge of the broken current collecting member is close to the vertical state, and the current collecting member has the possibility of being inserted into the electrode assembly after being pressed, which further causes the damage of the electrode assembly and reduces the product yield.

[0049] In view of this, the technical scheme is provided, a through buffer hole is arranged on the pin. The stress of the pin during the bending process can be weakened to the connection position of the pin and the shell, and the risk of breakage of the current collecting member at the connection position with the shell is reduced, and the technical problem of easy fixation failure between the current collecting member and the shell is improved.

[0050] Please refer to Figures 1 to 11 The utility model provides a current collecting member 130, a secondary battery 100 and an electronic device 1, the current collecting member 130 is used for connecting the shell 110 and the electrode assembly 120 in the secondary battery 100, and the current collecting member 130 comprises a current collecting body 131 and a plurality of pins 132.

[0051] Please refer to Figure 1 And Figure 2 The current collecting body 131 is used for connecting the electrode assembly 120, the shape of the current collecting body 131 can be any rotationally symmetrical shape, for example, can be circular, square, regular polygon, petal shape or other graphic shape with a symmetry center and capable of coinciding with the original graphic shape after rotating a certain angle around the symmetry center, and the limitation is not made to it, so as to be suitable for realizing the stable and reliable electrical connection relationship with the electrode assembly 120, and the center of the current collecting body 131 is the symmetry center of itself. The current collecting body 131 in the embodiment is approximately circular in shape.

[0052] Please refer to Figures 1 to 3The plurality of pins 132 are spacedly connected to the outer periphery of the current collecting body 131. The spacing of the plurality of pins 132 can not only reduce the processing difficulty of bending the pins 132, but also ensure the conductivity of the pins 132. The number of the pins 132 is not limited, and in the embodiment, the number of the pins 132 is four, which are evenly distributed in the circumferential direction of the current collecting body 131. The pin 132 and the current collecting body 131 can be integrally formed or fixedly connected as separate parts, which is not limited. In the embodiment, please refer to Figure 3 The pin 132 and the current collecting body 131 are integrally formed. Each pin 132 extends outward from the current collecting body 131 and is bent, so that the included angle between the pin 132 and the current collecting body 131 is a right angle or an obtuse angle. Preferably, the diameter of the current collecting body 131 is less than or equal to the diameter of the inner wall of the shell 110, and the diameter of the outer edge of the pin 132 is greater than or equal to the diameter of the inner wall of the shell 110. During the process of loading the current collecting member 130 into the shell 110, the pin 132 has a tendency to continue to bend in the vertical direction, and the included angle between the current collecting member 130 and the pin 132 becomes smaller, so that energy is stored, and the abutting and fixing between the pin 132 and the inner wall of the shell 110 are realized by the stored energy. This setting is conducive to the positioning of the current collecting member 130, thereby improving the welding quality. The shape of the pin 132 is not limited, as long as it can form a stable fixed connection with the shell 110 to realize conduction. In the embodiment, the pin 132 is a fan ring structure.

[0053] Please refer to Figures 1 to 6 Considering that when the mechanical seal is sealed, the pin 132 will have a large pulling force at the fixed connection position between the pin 132 and the shell 110 during the bending process, which may cause the pin 132 to break at the above-mentioned fixed connection position. In the embodiment, at least one buffer hole 1321 is arranged on each pin 132, which penetrates along the thickness direction of the pin 132 and extends along the circumferential direction of the pin 132. The number of the buffer hole 1321 is not limited, which can be one, two, three or more. The shape of the buffer hole 1321 is not limited, which can be circular, elliptical, oblong, rectangular or other irregular closed figures. In the embodiment, the buffer hole 1321 is an oblong hole.

[0054] Please refer to Figure 7 and Figure 9In the mechanical sealing process, when the pin 132 continues to bend towards the axis of the current collecting body 131: on the one hand, the buffer hole 1321 plays a role in reducing the difficulty of bending through the local thinning effect. On the other hand, the buffer hole 1321 can absorb stress through plastic deformation. In addition, the stress isolation area formed by the edge of the buffer hole 1321 blocks the stress conduction path. It can weaken the stress transmission of the pin 132 to the connection between the pin 132 and the shell 110 during bending, thereby reducing the risk of fracture of the current collecting member 130 at the connection with the shell 110, and improving the technical problem of easy fixation failure between the current collecting member 130 and the shell 110.

[0055] Considering that when the fixed connection mode of the pin 132 and the shell 110 is welding, due to the diffuse reflection of laser on the pin 132, the reflected laser has the risk of burning the electrode assembly 120 through the buffer hole 1321. Please refer to Figures 3 to 6 In an example of the current collecting member 130 of the utility model, the pin 132 includes a bending part 1322 and a shell connecting part 1323 connected to each other. When the pin 132 and the current collecting body 131 are integrally formed, the bending part 1322 is a fillet formed at the connection between the pin 132 and the current collecting body 131 during bending of the pin 132. The end of the bending part 1322 away from the shell connecting part 1323 is connected to the current collecting member 130, the shell connecting part 1323 extends from the bending part 1322 towards the direction away from the current collecting body 131, and the shell connecting part 1323 is connected at an angle with the current collecting body 131. The shell connecting part 1323 is used to connect the shell 110. The buffer holes 1321 are all located in the shell connecting part 1323. By avoiding the buffer holes 1321 from the bending part 1322, the buffer holes 1321 and the electrode assembly 120 can be made non-overlapping, the risk of the reflected laser irradiating the electrode assembly 120 through the buffer holes 1321 can be reduced, and the risk of the electrode assembly 120 being burned can be further reduced.

[0056] Please refer to Figures 3 to 6 In an example of the current collecting member 130 of the utility model, the hole wall profile of the buffer hole 1321 is a continuous and smooth closed profile. The shape of the buffer hole 1321 is not limited, for example, it can be a round hole, an oblong hole, an elliptical hole or other irregular continuous and smooth closed profiles, etc. By setting the hole wall profile of the buffer hole 1321 as a continuous and smooth closed profile, the problem of stress concentration caused by sharp edges or corners on the hole wall can be avoided, and the risk of the buffer hole 1321 being easily torn and damaged at the position of stress concentration can be reduced.

[0057] Please refer to Figure 4 and Figure 5In an example of the current utility model, along the circumference of the current collecting member 130, the sum of the lengths of the buffer holes 1321 on each pin 132 is L1, the length of the pin 132 is L2, and L1≤0.8L2. This setting is conducive to ensuring that the pin 132 has sufficient strength, thereby reducing the risk of fracture problems. It should be noted that in an embodiment, as shown in Figure 4 , the pin 132 is provided with one buffer hole 1321, and the length L1 of the buffer hole 1321 is as shown in Figure 4 . In another embodiment, as shown in Figure 5 , the pin 132 is provided with two buffer holes 1321, and the length L1 of the buffer hole 1321 is the sum of the lengths of the two buffer holes 1321, and the lengths of the two buffer holes 1321 are respectively shown by b and c, that is, L1=b+c.

[0058] Please refer to Figure 4 , in an example of the current utility model, along the direction in which the pin 132 extends outward from the current collecting body 131, the length of the buffer hole 1321 is greater than 0.1mm, and this size is shown by d in Figure 4 . This limitation is conducive to the buffer hole 1321 having sufficient deformation space to ensure that the buffer hole 1321 has the ability to absorb stress and block stress transmission, so as to be able to improve the technical problem of easy fixation failure between the current collecting member 130 and the shell 110.

[0059] Please refer to Figures 7 to 9 , the current utility model also provides a secondary battery 100, which comprises a shell 110, an electrode assembly 120, a current collecting member 130, a cover plate 140 and a pole 150.

[0060] Please refer to Figure 7The shell 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 can be achieved in various ways, such as one-piece stamping, one-piece casting or separate welding, as long as a stable sealing and electrical connection relationship can be formed. The surrounding of the side wall 112 is not limited, and can be cylindrical or prismatic, or any other closed-loop profile that can be matched with the end wall 111. In the 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 the end of the side wall 112 away from the end wall 111. The shell 110 formed by the end wall 111 and the side wall 112 has a receiving cavity for accommodating the electrode assembly 120, electrolyte and other necessary components of the battery. Specifically, the diameter of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc. The shell 110 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent rusting of the shell 110 during long-term use, a layer of anti-rust material such as metal nickel can be plated on the surface of the shell 110.

[0061] Referring to Figures 7 to 8 The electrode assembly 120 is accommodated in the shell 110, and the electrode assembly 120 is a component for electrochemical reaction in the secondary battery 100. One or more electrode assemblies 120 can be contained in the shell 110. The electrode assembly 120 includes a first electrode tab 121, a second electrode tab 123 and a separator 122 stacked and wound to form a wound structure. The first electrode tab 121 and the second electrode tab 123 have opposite polarities. In some embodiments, the first electrode tab 121 is a positive electrode tab, and the second electrode tab 123 is a negative electrode tab. In other embodiments, the first electrode tab 121 is a negative electrode tab, and the second electrode tab 123 is a positive electrode tab.

[0062] Referring to Figures 7 to 8 In the embodiment, the first electrode tab 121 is a negative electrode tab, and the first electrode tab 121 includes a negative electrode current collector 1211 and a negative electrode active material coated on the surface of the negative electrode current collector 1211. The negative electrode current collector 1211 includes a first coated area 1212 coated with the active material and a first uncoated area 1213 not coated with the active material. The first uncoated area 1213 is located at the end of the first electrode tab 121, and the first uncoated area 1213 extends beyond the separator 122 along the winding axis direction of the electrode assembly 120 and bends towards the winding axis to form a first tab 124. The first tab 124 is a corresponding negative electrode tab.

[0063] Referring to Figures 7 to 8The second tab 123 is a positive electrode tab. Specifically, the second tab 123 includes a positive electrode current collector 1231 and a positive electrode active material coated on a surface of the positive electrode current collector 1231. The positive electrode current collector 1231 includes a second coated area 1232 coated with the positive electrode active material and a second uncoated area 1233 uncoated with the positive electrode active material. The second uncoated area 1233 is located at an end of the second tab 123, extends out of the separator 122 along the winding axis direction of the electrode assembly 120, and is bent towards the winding axis to form a second tab 125. The second tab 125 is a corresponding positive electrode tab.

[0064] Referring to Figures 7 to 8 The separator 122 is arranged between the first tab 121 and the second tab 123 to separate the positive electrode active material layer and the negative electrode active material layer. In the example of the lithium ion secondary battery 100, the material of the positive electrode current collector 1231 can be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate. The material of the negative electrode current collector 1211 can be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material can be carbon or silicon. The base material of the separator 122 can be polypropylene (PP) or polyethylene (PE). To protect and insulate the electrode assembly 120, an insulating film can be wrapped outside the electrode assembly 120. The insulating film can be made of PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other high polymer materials.

[0065] Referring to Figure 7 and Figure 8 Further, the first tab 124 faces the end wall 111 or the opening 113, and the second tab 125 faces the other end of the housing 110. In the example, the second tab 125 faces the end wall 111 and is electrically connected to the pole 150 to make the pole 150 positively charged. The first tab 124 faces the opening 113, and the housing 110 is electrically connected to the first tab 124 to make the housing 110 negatively charged. However, in another example, the first tab 124 can be connected to the pole 150, and the second tab 125 can be connected to the housing 110.

[0066] Referring to Figure 7The pole post 150 is fixed to the end wall 111 and electrically connected with the electrode assembly 120. Specifically, the end wall 111 is provided with a pole post hole, the pole post 150 is installed through the pole post hole, and the pole post 150 is insulated from the end wall 111. The end of the pole post 150 towards the electrode assembly 120 is directly or indirectly electrically connected with the second pole lug 125 through the end wall 111. The pole post 150 can be in any suitable form that can be electrically connected with the second pole lug 125 of the electrode assembly 120 through the end wall 111, such as a circular, square, prism or special-shaped cross section that can achieve stable conduction. The pole post hole corresponds to the shape of the pole post 150. In the embodiment, the cross section of the pole post 150 is circular.

[0067] Referring to Figure 7 and Figure 9 , the cover plate 140 is sealingly installed in the opening 113. The outer edge of the cover plate 140 corresponds to the shape of the opening 113 and is connected with the side wall 112 to seal the opening 113. In a specific embodiment, before the shell 110 is rolled to form the rolling groove 114, the pin 132 is first welded to the side wall 112 of the shell 110 and forms a first welding mark 1324. At the same time of rolling the rolling groove 114, the pin 132 welded to the shell 110 continues to bend towards the axis of the shell 110 and finally bends towards the axis of the shell 110. At this time, the first welding mark 1324 is located on the surface of the rolling groove 114 facing the electrode assembly 120. The rolling groove 114 can limit the movement of the electrode assembly 120 towards the opening 113. The side of the rolling groove 114 away from the electrode assembly 120 is surrounded by an annular step formed on the shell 110, and the cover plate 140 is placed on the step. A sealing ring is arranged between the cover plate 140 and the shell 110. The edge of the opening 113 is potted to press the sealing ring tightly and form a reliable connection.

[0068] Referring to Figure 7 and Figure 9 , the current collecting member 130 is at least partially arranged between the rolling groove 114 and the electrode assembly 120. The electrode assembly 120 is electrically connected with the shell 110 through the current collecting member 130. Specifically, the current collecting member 130 includes a current collecting body 131 and a pin 132 connected to the outer periphery of the current collecting body 131. The current collecting body 131 is welded to the first pole lug 124 of the electrode assembly 120. The welding method can be ultrasonic welding, resistance welding, laser welding, etc., which is not limited. In the embodiment, laser welding is adopted. The first pole lug 124 is a negative pole lug. The material of the current collecting member 130 is preferably copper metal.

[0069] Referring to Figures 1 to 6In consideration of the fact that the pin 132 will have a large pulling force at the position where the pin 132 is fixedly connected to the shell 110 during the bending process, which will cause the pin 132 to be broken at the above-mentioned fixedly connected position, at least one buffer hole 1321 is arranged on each pin 132 in the embodiment, the buffer hole 1321 penetrates along the thickness direction of the pin 132 and extends along the circumferential direction of the pin 132. The number of the buffer hole 1321 is not limited, which can be one, two, three or more. The shape of the buffer hole 1321 is not limited, which can be circular, oval, oblong, rectangular or other irregular closed figures. The buffer hole 1321 in the embodiment is an oblong hole.

[0070] Please refer to Figure 9 By adopting the above-mentioned current collecting member 130, during the mechanical sealing process, when the pin 132 continues to bend towards the axis of the current collecting body 131: on the one hand, the buffer hole 1321 plays a role in reducing the bending difficulty through the local thinning effect. On the other hand, the buffer hole 1321 can absorb stress through plastic deformation. On the other hand, the stress isolation zone formed by the edge of the buffer hole 1321 blocks the stress conduction path. It can weaken the stress transmission of the pin 132 to the connection between the pin 132 and the shell 110 during the bending process, thereby reducing the risk of breaking of the current collecting member 130 at the connection with the shell 110, and improving the technical problem of easy fixation failure between the current collecting member 130 and the shell 110.

[0071] Please refer to Figures 4 to 6 Along the circumferential direction of the pin 132, the pin 132 includes a weakened portion 1325 provided with the buffer hole 1321. It should be noted that the region of the pin 132 provided with the buffer hole 1321 forms a weakened portion 1325 due to the weakening of the structural strength, such as the region enclosed by the dashed line shown in Figure 4 and Figure 5 . The first weld mark 1324 is located in the weakened portion 1325. The number of the buffer hole 1321 on each pin 132 is not limited, and the number of the first weld mark 1324 is also not limited. The number of the first weld mark 1324 can be consistent with the number of the buffer hole 1321, or can be less than the number of the buffer hole 1321, as long as the first weld mark 1324 is located in the weakened portion 1325.

[0072] In an embodiment, please refer to Figure 4 One buffer hole 1321 is arranged on the pin 132, and one first weld mark 1324 is arranged correspondingly. The first weld mark 1324 is located in the weakened portion 1325 corresponding to the buffer hole 1321. In another embodiment, please refer to Figure 5The pin 132 is provided with two buffer holes 1321, and two first solder marks 1324 are correspondingly arranged, and the two first solder marks 1324 are located in the weakened portions 1325 corresponding to the two buffer holes 1321. The welding process of the pin 132 and the shell 110 is carried out before the rolling groove 114, and in the welding process, the pulling force of the first solder mark 1324 in the weakened portion 1325 on the pin 132 causes the buffer hole 1321 to deform, so that the pin 132 is closer to the inner wall of the shell 110, the gap between the pin 132 and the shell 110 is reduced, and the risk of molten pool collapse of the first solder mark 1324 is reduced. In turn, the welding strength of the pin 132 and the shell 110 can be improved, which is beneficial to improve the technical problem that the fixing between the current collecting member 130 and the shell 110 is easy to fail.

[0073] In an example of the secondary battery 100 of the utility model, the minimum distance between the first solder mark 1324 and the edge of the buffer hole 1321 is greater than 1mm, such as Figure 9 indicated in a, which can be 1.2mm, 1.4mm, 1.5mm, 1.7mm or 1.8mm, etc. The setting can reduce the risk of damaging the buffer hole 1321 when welding the pin 132 and the shell 110.

[0074] Considering that when the secondary battery 100 is depressurized, the current collecting body 131 will be folded from the middle to the direction away from the electrode assembly 120, and the first solder mark 1324 is usually the folding fulcrum. In an example of the secondary battery 100 of the utility model, the minimum distance between the first solder mark 1324 and the edge of the buffer hole 1321 is less than 2mm, such as Figure 9 indicated in a. For example, it can be 1.2mm, 1.4mm, 1.5mm, 1.7mm or 1.8mm, etc. The setting can reduce the redundant length of the pin 132, which is beneficial to the root support when the current collecting body 131 is folded, and improves the safety performance of the secondary battery 100.

[0075] Please refer to Figure 4 , Figure 5 and Figure 9 In an example of the secondary battery 100 of the utility model, along the radial direction of the current collecting member 130, the buffer hole 1321 is located outside the electrode assembly 120. The setting can prevent the molten slag generated by welding from falling onto the electrode assembly 120 through the buffer hole 1321, causing burns to the electrode assembly 120, and preventing foreign matter from damaging the electrode assembly 120.

[0076] Please refer to Figure 6 and Figure 9In the secondary battery 100 example of the utility model, the electrode assembly 120 includes the cladding layer 126 cladded on the outermost side, the cladding layer 126 can be cladded on the outermost side of the electrode assembly 120 by winding, bonding or spraying curing and so on, and this is not limited. The material of the cladding layer 126 is not limited, for example, it can be polyimide, modified epoxy resin, fluorine rubber or silicone and so on. Considering that when the pin 132 and the shell 110 are welded, a small amount of scattered laser can be reflected into the inner wall of the shell 110 through the buffer hole 1321, and then reflected on the electrode assembly 120, causing the electrode assembly 120 to be scalded. Along the axial direction of the current collecting member 130, the cladding layer 126 is higher than the electrode assembly 120 near the one end of the current collecting member 130. The cladding layer 126 higher than the electrode assembly 120 can absorb scattered laser to prevent the diaphragm 122 from being scalded and causing damage to the electrode assembly 120.

[0077] Please refer to Figure 11 The utility model further provides an electronic device 1, electronic device 1 includes battery pack 10. The battery pack 10 includes the secondary battery 100 of any one of the above, in the battery pack 10 embodiment of the utility model, please refer to Figure 10 The battery pack 10 includes box body 101, box cover 102 and multiple secondary batteries 100, multiple secondary batteries 100 are placed in the box body 101, are connected in series or parallel with each other, or series and parallel hybrid, and the box cover 102 is capped on the box body 101 to protect multiple secondary batteries 100. It should be noted that the battery pack 10 can also include battery pack 10 thermal management system, circuit board and other parts in addition to the secondary battery 100 of the utility model, and the battery pack 10 can be a battery module or a battery pack, an energy storage cabinet, etc. ; Here will not be expanded one by one.

[0078] Further, the electronic device 1 further includes working part 11, and the working part 11 is electrically connected with the battery pack 10 to obtain power support. As an example, please refer to Figure 11The electronic device 1 is a vehicle, which can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid automobile or a range extended automobile, but is not limited thereto. The working part 11 is a vehicle body, and the battery pack 10 is arranged at the bottom of the vehicle body and provides power support for driving of the vehicle or operation of electrical elements in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The working part 11 can be a unit component capable of obtaining power of the battery pack 10 and making corresponding work, such as a fan blade rotating unit, a dust suction working unit of a dust collector, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not specially limit the above-mentioned electronic device 1.

[0079] The current collecting member is provided with the buffer hole penetrating the pin. The stress of the pin when being bent can be weakened to be transmitted to the connection between the pin and the shell, and the risk of the current collecting member being broken at the connection with the shell is reduced, and the technical problem of easy fixation failure between the current collecting member and the shell is improved. Therefore, the current collecting member effectively overcomes some practical problems in the prior art, and has high utilization value and use significance. The above-mentioned embodiments only exemplarily illustrate the principle and effect of the current collecting member, and are not used to limit the current collecting member. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the current collecting member. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the current collecting member should be covered by the claims of the current collecting member.

Claims

1. A current collecting member for connecting a case and an electrode assembly in a secondary battery, characterized by comprising: The application relates to a secondary battery, which comprises: a current collecting body for connecting the electrode assembly; a plurality of pins spaced apart from the outer periphery of the current collecting body, each pin extending outward from the current collecting body and being bent, the pin being used for connecting the shell; wherein at least one buffer hole is arranged on each pin, the buffer hole penetrating through the thickness direction of the pin and extending along the circumferential direction of the pin.

2. The current collecting member according to claim 1, characterized by The pin comprises a bent portion and a shell connecting portion connected to each other, one end of the bent portion away from the shell connecting portion being connected to the current collecting member, the shell connecting portion extending from the bent portion in a direction away from the current collecting body, the shell connecting portion being used for connecting the shell, and the buffer hole being located in the shell connecting portion.

3. The current collecting member according to claim 1, characterized by The hole wall profile of the buffer hole is a continuous smooth closed profile.

4. The current collecting member according to claim 1, characterized by Along the circumferential direction of the current collecting member, the sum of the lengths of the buffer holes on each pin is L1, and the length of the pin is L2, wherein L1<=0.8L2. Along the direction in which the pin extends outward from the current collecting body, the length of the buffer hole is greater than 0.1 mm.

5. The current collecting member according to claim 1, characterized by The application relates to a secondary battery, which comprises:

6. A secondary battery characterized by comprising: a shell comprising a surrounding side wall, one end of the side wall being provided with an opening, and the shell being provided with a rolling groove recessed towards the inside of the shell at the end close to the opening; an electrode assembly accommodated in the shell, the electrode assembly comprising a tab facing the opening; a current collecting member comprising a current collecting body and a plurality of pins spaced apart from the outer periphery of the current collecting body, the current collecting body being fixedly connected to the tab, the pin being bent towards the axis of the shell and being welded to the surface of the rolling groove facing the electrode assembly and being provided with a first welding mark, and at least one buffer hole being arranged on each pin, the buffer hole penetrating through the thickness direction of the pin and extending along the circumferential direction of the pin; wherein along the circumferential direction of the pin, the pin comprises a weakened portion provided with a buffer hole, and the first welding mark is located in the weakened portion. The minimum distance between the first welding mark and the edge of the buffer hole is greater than 1 mm.

7. The secondary battery according to claim 6, characterized by The minimum distance between the first welding mark and the edge of the buffer hole is less than 2 mm.

8. The secondary battery according to claim 7, characterized by Along the radial direction of the current collecting member, the buffer hole is located outside the electrode assembly.

9. The secondary battery according to claim 6, characterized by The electrode assembly comprises a cladding layer cladded on the outermost side, and along the axial direction of the current collecting member, the cladding layer is higher than the end of the electrode assembly close to the current collecting member.

10. The secondary battery according to claim 6, characterized by The application relates to a secondary battery, which comprises a battery pack, and the battery pack comprises the secondary battery according to any one of claims 6 to 10.

11. An electronic device, comprising: ​

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