Secondary battery and electronic device

Abstract

The utility model provides a secondary battery and an electronic device. The secondary battery comprises an electrode assembly, a shell and a current collecting component, the shell accommodates the electrode assembly and comprises a side wall with an opening at one end, and one side, close to the opening, of the side wall comprises a rolling groove sunken towards the interior of the shell; the current collecting component comprises a current collecting body and a shell connecting part arranged on the outer periphery of the current collecting body, the current collecting body is connected with the electrode assembly, the shell connecting part is bent towards the center of the current collecting body, and the shell connecting part is welded to the rolling groove; a bending part is arranged between the shell connecting part and the current collecting body, the bending part comprises a first bending section and a second bending section which are in angular connection, one end, far away from the second bending section, of the first bending section is connected with the shell connecting part and extends towards the central axis of the shell, and the second bending section is connected with the current collecting body and extends towards the direction deviating from the electrode assembly; the technical problems that the overall consistency of the electrode assembly is improved, and the product yield is reduced can be solved.

Description

TECHNICAL FIELD

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

[0002] Cylindrical battery is more and more favored by major car enterprises due to its high safety, long service life, excellent fast charging performance, excellent battery consistency and low production cost, and the consistency difference in its manufacturing process is the key factor limiting its yield improvement.

[0003] In the assembling process of cylindrical battery, the positive and negative current collecting members are first welded with the electrode assembly, and the positive current collecting member is then welded and connected with the pole, and the welding deviation of the above two welding processes will affect the concentricity of the electrode assembly and the shell, if the concentricity of the electrode assembly and the shell is low, the shell connecting part of the negative current collecting member and the shell welding will obviously pull the electrode assembly horizontally, so that the internal shear stress of the electrode assembly is generated and the local gap in the electrode assembly is increased, and the overall consistency of the electrode assembly and the product yield are reduced. SUMMARY

[0004] The utility model provides a kind of secondary battery and electronic device to improve the technical problem of the overall consistency of electrode assembly and the reduction of product yield.

[0005] To achieve the above object and other related purposes, the utility model provides a kind of secondary battery and electronic device, the secondary battery includes electrode assembly, shell and current collecting member;The shell contains the electrode assembly, and the shell includes the side wall of one end opening, the side wall includes the rolling groove recessed to the shell interior near the side of opening, and the rolling groove limits the electrode assembly to move to the opening direction;Current collecting member is at least partially arranged between rolling groove and electrode assembly, and the current collecting member includes current collecting body and shell connecting part arranged at the peripheral edge of current collecting body, and the current collecting body is connected with the electrode assembly, and the shell connecting part is bent to the center of current collecting body, and the shell connecting part is welded with the surface of rolling groove facing the electrode assembly;Bending part is arranged between shell connecting part and current collecting body, and the bending part includes first bending section and second bending section connected at an angle, and the first bending section is connected with shell connecting part at one end away from the second bending section, and extends to the central axis of shell, and the second bending section is connected with current collecting body at one end away from the first bending section, and extends in the direction away from the electrode assembly.

[0006] In the technical scheme, the welding process of the shell connecting portion and the shell makes the current collecting member and the shell in the concentric position, in the case that the concentricity of the electrode assembly and the shell is low, that is, the electrode assembly is deviated to one side in the shell, the bending portion arranged between the shell connecting portion and the current collecting body is stretched transversely or further folded to release the transverse shearing force between the current collecting body and the electrode assembly, so as to prevent the radial shearing force from being formed in the electrode assembly, cause the local state of the electrode assembly to be abnormal, and further improve the consistency of the electrode assembly; meanwhile, the transverse shearing force is prevented from tearing the welding connection between the current collecting body and the electrode assembly, so as to improve the welding quality of the current collecting member and the electrode assembly, and further improve the process consistency and product yield.

[0007] In addition, due to the influence of the roll groove and the bump sealing process, the current collecting member is subjected to radial extrusion, and if the stress cannot be released, the middle part of the current collecting member is prone to be raised. The second bending segment is connected to the current collecting body at one end and extends away from the electrode assembly, so that the two ends of the second bending segment have a height difference along the height direction of the secondary battery, and the current collecting member as a whole protrudes to one side of the electrode assembly. Since the welding position of the shell connecting portion and the shell is fixed, the protruding current collecting member can press down the electrode assembly to compensate for the tendency of the middle part of the current collecting member to be raised, so that the current collecting member can keep close contact with the electrode assembly after assembly, reduce the risk of welding tearing and increased internal resistance, and further improve the product yield and consistency.

[0008] In the example of the secondary battery of the utility model, along the radial direction of the secondary battery, the one end of the second bending segment connected to the first bending segment is located inside the one end of the second bending segment connected to the current collecting body.

[0009] In the technical scheme, the bending portion is transversely stretched and deformed towards the side wall, so as to release the transverse shearing force between the current collecting body and the electrode assembly, prevent the radial shearing force from being formed in the electrode assembly, cause the local state of the electrode assembly to be abnormal, and further improve the consistency of the electrode assembly.

[0010] In the example of the secondary battery of the utility model, along the radial direction of the secondary battery, the one end of the second bending segment connected to the current collecting body is located inside the one end of the second bending segment connected to the first bending segment.

[0011] In the technical scheme, the bending portion is folded towards the axis direction of the secondary battery, so as to release the transverse shearing force between the current collecting body and the electrode assembly, prevent the radial shearing force from being formed in the electrode assembly, cause the local state of the electrode assembly to be abnormal, and further improve the consistency of the electrode assembly.

[0012] In the example of the secondary battery of the utility model, the length of the first bending segment is a, and 2mm≤a≤4mm.

[0013] In the technical scheme, the length of the first bending section satisfies a≥2mm, which can provide compensation space for stretching or folding of the bending part; and the length of the first bending section satisfies a≤4mm, which can reduce the occupation of the radial dimension of the current collecting member, ensure the radial length of the welding mark formed by welding of the current collecting member to the electrode assembly, and further realize the effect of low internal resistance of the secondary battery.

[0014] In the secondary battery example, the length of the second bending section is b, wherein 0.5mm≤b≤1.5mm.

[0015] In the technical scheme, the length of the second bending section satisfies b≥0.5mm, which can provide compensation space for stretching or folding of the bending part; and b≤1.5mm, which can limit the occupation of the secondary battery in the height direction of the bending part, so as to realize high space utilization and energy density of the secondary battery.

[0016] In the secondary battery example, a first weak part extending along the circumference of the secondary battery is arranged between the first bending section and the second bending section; and / or a second weak part extending along the circumference of the secondary battery is arranged between the second bending section and the current collecting body; and / or a third weak part extending along the circumference of the secondary battery is arranged between the first bending section and the shell connecting part.

[0017] In the technical scheme, the stress generated when the corresponding part is bent can be weakened at the positions of the first weak part, the second weak part and the third weak part, and the bending at the positions of the first weak part, the second weak part and the third weak part is facilitated. In addition, due to the low strength of the first weak part, the second weak part and the third weak part, deformation will first occur at the first weak part, the second weak part and the third weak part under the action of stress during sealing, so as to reduce the transmission of stress to the positions of the welding of the current collecting body and the electrode assembly and the welding of the shell connecting part and the shell, and further improve the welding failure of the current collecting body and the electrode assembly, the shell connecting part and the shell caused by bending stress.

[0018] In the secondary battery example, the middle part of the current collecting body includes a raised part, which gradually rises towards the electrode assembly from the outside to the inside along the radial direction of the secondary battery.

[0019] In the technical scheme, the setting can further compensate the upward tendency of the middle part of the current collecting member during assembly.

[0020] In the secondary battery example, the diameter of the outer periphery of the raised part is D, wherein 8mm≤D≤37mm.

[0021] In the above technical solution, since the welding position of the current collecting body and the electrode assembly is mainly located in the annular region of 8mm≤D≤37mm, and the outer periphery of the raised portion is located in the annular region of 8mm≤D≤37mm, it is beneficial to compensate for the upward tendency of the current collecting body in the above region, and reduce the risk of the current collecting body and the electrode assembly being pulled off at the welding position due to the upward tendency of the middle part of the current collecting body.

[0022] In the example of the secondary battery of the utility model, along the height direction of the secondary battery, the height of the raised portion protruding from the current collecting body is H, and 0.5mm≤H≤1.5mm.

[0023] In the above technical solution, the limitation of 0.5mm≤H≤1.5mm can compensate for the upward tendency of the middle part of the current collecting body, and can also prevent the risk of false welding due to the raised portion being too high, thereby improving the reliability of the welding of the current collecting body and the electrode assembly.

[0024] 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.

[0025] In the secondary battery of the utility model, the shell connecting portion and the shell are in the concentric position during the welding process, and the bending portion arranged between the shell connecting portion and the current collecting body releases the transverse shear force between the current collecting body and the electrode assembly by transverse stretching or further folding, so as to prevent the formation of radial shear force inside the electrode assembly and cause the abnormal local state of the electrode assembly, thereby improving the consistency of the electrode assembly; at the same time, the transverse shear force is prevented from tearing the welding connection position of the current collecting member and the electrode assembly, so as to improve the welding quality of the current collecting member and the electrode assembly, and further realize the beneficial effects of improving the process consistency and product yield.

[0026] In addition, due to the influence of the rolling groove and the bump sealing process, the current collecting member is subjected to radial extrusion, and the middle part of the current collecting member is prone to be raised due to the inability to release stress. The second bending segment is connected to the current collecting body at one end and extends away from the electrode assembly, so that the two ends of the second bending segment have a height difference along the height direction of the secondary battery, and the current collecting member as a whole protrudes towards one side of the electrode assembly. Since the welding position of the shell connecting portion and the shell is fixed, the protruding current collecting member can press down the electrode assembly to compensate for the tendency of the middle part of the current collecting member to be raised, so that the current collecting member maintains a close state with the electrode assembly after assembly, reduces the risk of welding tearing and increased internal resistance, and further improves the product yield and consistency. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0028] Figure 1 It is a whole structure schematic view of a secondary battery embodiment of the present application.

[0029] Figure 2 It is an electrode assembly structure schematic view of a secondary battery embodiment of the present application.

[0030] Figure 3 It is Figure 1 It is a local enlarged view of A in the middle.

[0031] Figure 4 It is a sectional view of a current collecting member of a secondary battery embodiment of the present application.

[0032] Figure 5 It is a sectional view of a current collecting member of another secondary battery embodiment of the present application.

[0033] Figure 6 It is a sectional view of a current collecting member of still another secondary battery embodiment of the present application.

[0034] Figure 7 It is a top view of a current collecting member of a secondary battery embodiment of the present application.

[0035] Figure 8 It is a front view of a current collecting member of a secondary battery embodiment of the present application.

[0036] Figure 9 It is a local enlarged view of B in the middle in a secondary battery embodiment of the present application. Figure 8

[0037] Figure 10 It is a local enlarged view of B in the middle in still another secondary battery embodiment of the present application. Figure 8

[0038] Figure 11 It is a top view of a current collecting member of a secondary battery embodiment of the present application.

[0039] Figure 12 It is a front view of a current collecting member of a secondary battery embodiment of the present application.

[0040] Figure 13 It is a schematic view of a battery pack embodiment of the present application.

[0041] ​​Figure 14 Figure 1 is a schematic diagram of an embodiment of the electronic device

[0042] Element number explanation:

[0043] 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; 130, current collecting member; 131, current collecting body; 132, shell connecting part; 133, bending part; 1331, first bending section; 1332, second bending section; 1333, first weak part; 1334, second weak part; 1335, third weak part; 134, raised part; 140, cover plate; 150, pole. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be described in detail with specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. The present application can also be implemented or applied in other different specific embodiments, and each detail in the specification can be modified or changed based on different views 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 for describing specific specific embodiments, not for limiting the protection scope of the present application. The test methods not specified in the following embodiments are usually performed under conventional conditions or under the conditions recommended by the manufacturers.

[0045] When the embodiments give a numerical range, it should be understood that, unless otherwise specified by the present application, each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are consistent with the understanding of the prior art by those skilled in the art and the description of the present application. Any method, equipment and material of the prior art similar or equivalent to the method, equipment and material in the embodiments of the present application can be used to realize the present application.

[0046] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" in the specification are only for the convenience of clear description, and are not used to limit the scope of the utility model, and the change or adjustment of the relative relationship is also regarded as the scope of the utility model.

[0047] 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.

[0048] The secondary battery further includes a case, a cover plate, and a post, the case including an end wall and a side wall surrounding the end wall, one end of the side wall having an opening, the electrode assembly being assembled into the case via the opening of the case, the cover plate being used to cover the opening of the case to achieve sealing, and the post being electrically connected to the electrode assembly through the end wall to guide the electrical energy generated by the electrode assembly out.

[0049] The mainstream packaging method 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 collector member is electrically connected to the electrode assembly and the case at the same time to achieve the electrical connection between the electrode assembly and the case. Specifically, a rolling groove recessed towards the inside of the case is rolled on the side wall of the case, the edge of the current collector 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 member is arranged between the cover plate and the case, and the cover plate is pressed against the sealing member in a potted manner at the edge of the opening to form a reliable connection and achieve the sealing of the case.

[0050] In the assembly process of the cylindrical battery, the positive and negative current collector members are first welded to the electrode assembly, and the positive current collector member is then welded to the post. The inventors have found that the welding deviation of the above two welding processes will affect the concentricity of the electrode assembly and the case. The welding of the case connecting portion of the negative current collector member to the case will correct the concentricity deviation to a certain extent. If the concentricity of the electrode assembly and the case is low, the welding of the case connecting portion of the negative current collector member to the case will obviously pull the electrode assembly laterally, causing internal shear stress in the electrode assembly and increasing the local voids in the electrode assembly, reducing the consistency of the electrode assembly as a whole, deteriorating the performance of the local position of the electrode assembly, and reducing the product yield.

[0051] In view of this, the utility model provides a technical scheme, a bending portion is arranged between the case connecting portion and the current collector body, the bending portion releases the lateral shear force between the current collector body and the electrode assembly by being stretched laterally or further folded, so as to prevent the formation of radial shear force in the electrode assembly and cause the local state of the electrode assembly to be abnormal, thereby achieving the effect of improving the consistency of the electrode assembly.

[0052] Please refer to Figures 1 to 14The utility model provides a secondary battery 100 and electronic device 1, this secondary battery 100 includes: casing 110, electrode assembly 120, current collection member 130, cover plate 140 and pole 150.

[0053] Please refer to Figure 1 Casing 110 includes end wall 111 and the side wall 112 of surrounding end wall 111, as long as can form stable sealing and electric connection relation, the connection between end wall 111 and side wall 112 can be realized through multiple ways, for example can be integrated stamping forming, integrated casting forming or split welding form etc. The surrounding of side wall 112 is not limited, can present cylindrical or prismatic surrounding, also can along other any can with end wall 111 matching closed loop profile surrounding, and the outer edge of end wall 111 is circular in this embodiment, and side wall 112 is cylindrical and surrounds the outer edge of end wall 111, and the circular opening 113 is formed at the end of side wall 112 away from end wall 111. Form the accommodating cavity in the casing 110 surrounded by end wall 111 and side wall 112 for accommodating electrode assembly 120, electrolyte and other battery necessary components. Specifically, the diameter size of casing 110 can be determined according to the specific size of electrode assembly 120, such as 18mm, 21mm, 46mm etc. The material of casing 110 can be multiple, such as copper, iron, aluminum, steel, aluminum alloy etc., in order to prevent rust of casing 110 when long-term use, still can be plated with a layer of rust -resistant material such as metal nickel etc. on the surface of casing 110.

[0054] Please refer to Figures 1 to 2 Electrode assembly 120 is accommodated in casing 110, and electrode assembly 120 is the component of secondary battery 100 that occurs electrochemical reaction. Casing 110 can include one or more electrode assemblies 120. Electrode assembly 120 includes the winding structure of first pole piece 121, second pole piece 123 and diaphragm 122 laminated and wound, and the polarity of first pole piece 121 and second pole piece 123 is opposite, in some embodiments, first pole piece 121 is positive pole piece, and second pole piece 123 is negative pole piece, and in some other embodiments, first pole piece 121 is negative pole piece, and second pole piece 123 is positive pole piece.

[0055] Please refer to Figures 1 to 2In the embodiment, the first tab 121 is a negative electrode tab, and the first tab 121 includes a negative electrode current collector 1211 and a negative electrode active material, and the negative electrode active material is 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 uncoated with the active material, the first uncoated area 1213 is located at the end of the first tab 121, and the first uncoated area 1213 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 first tab 124, and the first tab 124 is a corresponding negative electrode tab.

[0056] Referring to Figures 1 to 2 The 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, and the positive electrode active material is coated on the surface of the positive electrode current collector 1231; the positive electrode current collector 1231 includes a second coated area 1232 coated with the active material and a second uncoated area 1233 uncoated with the active material, the second uncoated area 1233 is located at the end of the second tab 123, and the second uncoated area 1233 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, and the second tab 125 is a corresponding positive electrode tab.

[0057] Referring to Figures 1 to 2 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. Taking the lithium ion secondary battery 100 as an example, 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, etc. 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, etc. The base material of the separator 122 can be polypropylene (PP) or polyethylene (PE), etc. In order to protect and insulate the electrode assembly 120, an insulating film can also be wrapped outside the electrode assembly 120, and the insulating film can be synthesized by PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC) or other high molecular polymer materials.

[0058] Referring to Figure 1 and Figure 2Further, the first lug 124 faces the end wall 111 or the opening 113, and the second lug 125 faces the other end of the shell 110. In this embodiment, the second lug 125 faces the end wall 111, and the pole 150 is electrically connected to the second lug 125 to make the pole 150 positively charged. The lug facing the opening 113 is the first lug 124, and the shell 110 is electrically connected to the first lug 124 to make the shell 110 negatively charged. However, in another embodiment, the first lug 124 can be connected to the pole 150, and the second lug 125 can be connected to the shell 110.

[0059] Referring to Figure 1 The pole 150 is fixed to the end wall 111 and electrically connected to the electrode assembly 120. Specifically, the end wall 111 is provided with a pole hole, and the pole 150 is installed through the pole hole and insulated from the end wall 111. One end of the pole 150 facing the electrode assembly 120 is directly or indirectly electrically connected to the second lug 125 through the end wall 111. The pole 150 can have any suitable form that can pass through the end wall 111 and be electrically connected to the second lug 125 of the electrode assembly 120. For example, the pole 150 can have a circular, square, prismatic, or any other suitable cross-sectional shape that can achieve stable electrical conduction. The pole hole corresponds to the shape of the pole 150. In this embodiment, the pole 150 has a circular cross-section.

[0060] Referring to Figure 1 and Figure 3 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 to the side wall 112 to seal the opening 113. In a specific embodiment, the side wall 112 includes an annular groove 114 recessed into the shell 110 near the opening 113. The groove 114 can limit the movement of the electrode assembly 120 toward the opening 113. The side of the groove 114 away from the electrode assembly 120 is surrounded by a ring-shaped step on the shell 110, and the cover plate 140 is placed on the step. A sealing ring is provided 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.

[0061] Referring to Figure 1 , Figure 3 , Figure 7 and Figure 11The current collecting member 130 is arranged at least partially between the rolling groove 114 and the electrode assembly 120, and the electrode assembly 120 is electrically connected to the shell 110 through the current collecting member 130. It should be noted that the current collecting member 130 can have any shape that is rotationally symmetrical, for example, the current collecting member 130 can have a circular shape, a square shape, a regular polygonal shape, a petal shape, or any other shape that has a center of symmetry and can coincide with the original shape after rotating a certain angle around the center of symmetry. The shape of the current collecting member 130 is not limited in this regard, and the shape of the current collecting member 130 is suitable to achieve a stable and reliable electrical connection. The center of the current collecting member 130 is the center of symmetry of the current collecting member 130.

[0062] Specifically, referring to Figure 3 The current collecting member 130 includes a current collecting body 131 and a shell connecting portion 132 arranged at the outer periphery of the current collecting body 131. The current collecting body 131 is welded to the electrode assembly 120. Specifically, the current collecting body 131 is welded to the first tab 124. The welding method can be ultrasonic welding, resistance welding, laser welding, etc. The current collecting member 130 is preferably made of copper metal. It should be noted that the current collecting body 131 is the part of the current collecting member 130 that is attached to the first tab 124 and can be used for welding the current collecting member 130 to the first tab 124. In order to improve the positioning, processing convenience, interchangeability and uniformity of the current collecting member 130 during installation, the current collecting body 131 in the present embodiment has a circular structure.

[0063] Referring to Figure 3 , Figure 7 and Figure 11 The shell connecting portion 132 can have a whole annular structure or one or more sector annular structures, as long as the shell connecting portion 132 meets the flow guiding requirements and welding strength requirements between the shell connecting portion 132 and the shell 110. The shell connecting portion 132 in the present embodiment has four sector annular structures evenly connected to the outer periphery of the current collecting body 131. Before the shell 110 is rolled over the rolling groove 114, the shell connecting portion 132 is first welded to the side wall 112 of the shell 110. While the rolling groove 114 is being rolled, the shell connecting portion 132 that is welded to the shell 110 continues to bend towards the center of the current collecting body 131, and finally forms a bend towards the axis of the shell 110 and is welded to the surface of the rolling groove 114 that faces the electrode assembly 120.

[0064] In the case that the electrode assembly 120 is eccentric to the housing 110, i.e. the electrode assembly 120 is deviated to one side in the housing 110, the welding of the housing 110 connecting portion and the housing 110 can make the current collecting member 130 and the housing 110 in the concentric position, and the welding of the housing 110 connecting portion and the housing 110 can obviously pull the electrode assembly 120 in the transverse direction, so that the internal shear stress of the electrode assembly 120 is generated and the local gap in the electrode assembly 120 is increased, and the consistency of the whole electrode assembly 120 and the product yield are reduced. In an example of the secondary battery 100, please refer to Figures 3 to 6 , the bending portion 133 is arranged between the housing 110 connecting portion and the current collecting body 131, the bending portion 133 includes the first bending segment 1331 and the second bending segment 1332 which are connected at an angle, one end of the first bending segment 1331 which is away from the second bending segment 1332 is connected to the housing 110 connecting portion and extends to the central axis of the housing 110, and one end of the second bending segment 1332 which is away from the first bending segment 1331 is connected to the current collecting body 131 and extends to the direction away from the electrode assembly 120.

[0065] Please refer to Figures 7 to 10 , the bending portion 133 is an integral molding structure or a split welding structure with the current collecting body 131 and the housing 110 connecting portion, and the bending portion 133 in the embodiment is an integral molding structure. The included angle between the first bending segment 1331 and the second bending segment 1332 can be any value, and the included angle between the first bending segment 1331 and the second bending segment 1332 is close to a right angle before the housing 110 connecting portion is bent, and the included angle between the first bending segment 1331 and the second bending segment 1332 is changed during the bending process of the housing 110 connecting portion, so that the transverse stretching or further folding of the bending portion 133 is realized, for example, in an embodiment, please refer to Figure 4 , every two opposite bending portions 133 of the four bending portions 133 are stretched in the transverse direction and the other two are further folded; in another embodiment, please refer to Figure 5 , every two opposite bending portions 133 of the four bending portions 133 are further folded; in still another embodiment, please refer to Figure 6 , every two opposite bending portions 133 of the four bending portions 133 are stretched in the transverse direction. It can be understood that Figures 4 to 6 , the deformation of the bending portion 133 is not limited to the above several kinds, and the degree of the bending deformation is not limited.

[0066] The bending part 133 can release the transverse shearing force between the current collecting body 131 and the electrode assembly 120 through deformation, so as to prevent the radial shearing force from being formed inside the electrode assembly 120, the partial state of the electrode assembly 120 is abnormal, and the consistency of the electrode assembly 120 is improved; meanwhile, the transverse shearing force is prevented from tearing the welding connection between the current collecting member 130 and the first tab 124, the welding quality of the current collecting member 130 and the electrode assembly 120 is improved, and the beneficial effects of improving the process consistency and product yield are realized.

[0067] In addition, due to the influence of the rolling groove 114 and the bump sealing process, the current collecting member 130 is subjected to radial extrusion, and if the stress cannot be released, the middle part of the current collecting member 130 is prone to be warped. The second bending segment 1332 is connected to the current collecting body 131 at one end and extends away from the electrode assembly 120, so that the two ends of the second bending segment 1332 have a height difference along the height direction of the secondary battery 100, and the current collecting member 130 as a whole protrudes to the side of the electrode assembly 120. Since the welding position of the shell 110 connecting part and the shell 110 is fixed, the protruding current collecting member 130 can press down the electrode assembly 120, so as to compensate the warping trend of the middle part of the current collecting member 130, keep the current collecting member 130 in close contact with the electrode assembly 120 after assembly, reduce the risk of welding tearing and increased internal resistance, and further improve the product yield and consistency.

[0068] Please refer to Figure 5 In an example of the secondary battery 100 of the utility model, along the radial direction of the secondary battery 100, the one end of the second bending segment 1332 connecting the first bending segment 1331 is located inside the one end of the second bending segment 1332 connecting the current collecting body 131. The bending part 133 in this example is stretched and deformed in the direction of the side wall 112, and the transverse shearing force between the current collecting body 131 and the electrode assembly 120 is released through the above-mentioned manner, so as to prevent the radial shearing force from being formed inside the electrode assembly 120, the partial state of the electrode assembly 120 is abnormal, and the consistency of the electrode assembly 120 is improved.

[0069] Please refer to Figure 6 In an example of the secondary battery 100 of the utility model, along the radial direction of the secondary battery 100, the one end of the second bending segment 1332 connecting the current collecting body 131 is located inside the one end of the second bending segment 1332 connecting the first bending segment 1331. The bending part 133 in this example is folded in the direction of the axis of the secondary battery 100, and the transverse shearing force between the current collecting body 131 and the electrode assembly 120 is released through the above-mentioned manner, so as to prevent the radial shearing force from being formed inside the electrode assembly 120, the partial state of the electrode assembly 120 is abnormal, and the consistency of the electrode assembly 120 is improved.

[0070] Please refer toFigures 8 to 9 In the secondary battery 100 example of the utility model, the length of the first bending section 1331 is a, wherein, 2mm≤a≤4mm. For example, it can be 2mm, 2.5mm, 3mm, 3.5mm or 4mm, etc. The length of the first bending section 1331 satisfies a≥2mm, which can provide compensation space for the stretching or folding of the bending part 133; and satisfies a≤4mm, which can reduce the occupation of the radial dimension of the current collecting member 130, ensure the radial length of the welding mark formed by welding the current collecting member 130 to the electrode assembly 120, and further realize the effect of the secondary battery 100 having a lower internal resistance.

[0071] Please refer to Figures 8 to 9 In the secondary battery 100 example of the utility model, the length of the second bending section 1332 is b, wherein, 0.5mm≤b≤1.5mm. For example, it can be 0.5mm, 0.75mm, 1mm or 1.5mm, etc. The length of the second bending section 1332 satisfies b≥0.5mm, which can provide compensation space for the stretching or folding of the bending part 133; and b≤1.5mm, which can limit the occupation of the bending part 133 in the height direction of the secondary battery 100 to realize the secondary battery 100 having a higher space utilization and energy density.

[0072] Please refer to Figures 8 to 10 In the secondary battery 100 example of the utility model, a first weak part 1333 extending along the circumference of the secondary battery 100 is arranged between the first bending section 1331 and the second bending section 1332; and / or a second weak part 1334 extending along the circumference of the secondary battery 100 is arranged between the second bending section 1332 and the current collecting body 131; and / or a third weak part 1335 extending along the circumference of the secondary battery 100 is arranged between the first bending section 1331 and the shell 110 connecting part. For example, in some embodiments, only the first weak part 1333, only the second weak part 1334 or only the third weak part 1335 is arranged, and in the embodiment, only the third weak part 1335 is arranged, please refer to Figure 9 ; in another embodiment, a combination of two of the first weak part 1333, the second weak part 1334 and the third weak part 1335 is arranged; in still another embodiment, please refer to Figure 10 The first weak part 1333, the second weak part 1334 and the third weak part 1335 are arranged at the same time.

[0073] At the positions of the first, second and third weakened portions 1333, 1334 and 1335, the stress generated when the corresponding portions are bent can be weakened, and the bending at the first, second and third weakened portions 1333, 1334 and 1335 is facilitated. At the same time, due to the low strength of the first, second and third weakened portions 1333, 1334 and 1335, deformation is first generated at the first, second and third weakened portions 1333, 1334 and 1335 under the action of stress when the seal is formed, so as to reduce the transmission of stress to the positions where the current collecting body 131 and the electrode assembly 120 are welded, and the positions where the connecting portion of the shell 110 and the shell 110 are welded, thereby improving the problem of welding failure of the current collecting body 131, the electrode assembly 120, the connecting portion of the shell 110 and the shell 110 caused by bending stress.

[0074] Please refer to Figures 11 to 12 In an example of the secondary battery 100 of the present application, the middle portion of the current collecting body 131 includes a raised portion 134, which gradually rises from the outside to the inside along the radial direction of the secondary battery 100 and towards the electrode assembly 120. This arrangement can further compensate for the tendency of the middle portion of the current collecting member 130 to be raised upwards during assembly. This allows the current collecting member 130 to maintain a close contact with the electrode assembly 120 after assembly, thereby reducing the risk of welding tear and increased internal resistance, and further improving product yield and consistency.

[0075] Please refer to Figures 11 to 12 In an example of the secondary battery 100 of the present application, the diameter of the outer periphery of the raised portion 134 is D, where 8mm≤D≤37mm. For example, it can be 8mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm or 37mm, etc. Since the welding position of the current collecting body 131 and the first tab 124 is mainly located in the annular region of 8mm≤D≤37mm, the outer periphery of the raised portion 134 is limited to be located in the annular region of 8mm≤D≤37mm, which is conducive to compensating for the tendency of the current collecting body 131 to be raised upwards in the above-mentioned region, and reducing the risk of the welding position of the current collecting body 131 and the electrode assembly 120 being pulled apart due to the middle portion of the current collecting body 131 being raised upwards.

[0076] Please refer to Figures 11 to 12 In an example of the secondary battery 100 of the present application, along the height direction of the secondary battery 100, the height of the raised portion 134 protruding from the current collecting body 131 is H, where 0.5mm≤H≤1.5mm. For example, it can be 0.5mm, 0.75mm, 1mm or 1.5mm, etc. The raised portion 134 satisfying the above range can not only compensate for the tendency of the middle portion of the current collecting body 131 to be raised upwards, but also prevent the risk of virtual welding due to the raised portion 134 being too high, and can improve the reliability of the welding of the current collecting body 131 and the electrode assembly 120.

[0077] Please refer to Figure 14 The utility model also provides an electronic device 1, electronic device 1 includes battery pack 10. Please refer to Figure 13 Battery pack 10 includes the secondary battery 100 of any one of the above, in an embodiment of the utility model battery pack 10, battery pack 10 includes box 101, box cover 102 and multiple secondary batteries 100, multiple secondary batteries 100 are placed in box 101, and are connected in series or parallel with each other, or series and parallel hybrid, and box cover 102 is capped on box 101 to protect multiple secondary batteries 100. It needs to be explained that 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 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, please refer to Figure 14 Working part 11 is electrically connected with battery pack 10 to obtain power support. As an example, 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 vehicle, a hybrid vehicle or an extended range vehicle, but is not limited thereto. Working part 11 is a vehicle body, and battery pack 10 is arranged at the bottom of the vehicle body and provides power support for the running of the vehicle or the operation of the electrical elements in the vehicle. However, in other embodiments, 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. Working part 11 can be a unit component capable of obtaining the power of 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 car toy, an electric ship toy and an electric plane 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 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 secondary battery, the bending part releases the transverse shearing force between the current collecting body and the electrode assembly through transverse stretching or further folding, so as to prevent the formation of radial shearing force inside the electrode assembly, cause the partial state of the electrode assembly to be abnormal, and further achieve the effect of improving the consistency of the electrode assembly; meanwhile, the transverse shearing force is prevented from tearing the welding line, so as to improve the welding quality of the current collecting member and the electrode assembly, and further realize the beneficial effects of improving the process consistency and the product yield. Therefore, the utility model effectively overcomes some practical problems in the prior art, thereby having high utilization value and use significance. The above embodiment only exemplarily illustrates the principle and effect of the utility model, and is not used for limiting the utility model. Any person skilled in the art can modify or change the above embodiment without departing from the spirit and category of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art under the spirit and technical thought disclosed by the utility model still should be covered by the claims of the utility model.

Claims

1. A secondary battery, characterized in that, include: Electrode assembly; A housing that accommodates the electrode assembly, the housing including a sidewall with an opening at one end, the sidewall near the opening including a groove recessed into the housing, the groove restricting movement of the electrode assembly toward the opening; A current collecting component is at least partially disposed between the groove and the electrode assembly. The current collecting component includes a current collecting body and a housing connecting portion disposed on the outer periphery of the current collecting body. The current collecting body is connected to the electrode assembly. The housing connecting portion is bent toward the center of the current collecting body. The housing connecting portion is welded to the surface of the groove facing the electrode assembly. A bend is provided between the housing connection and the current collector body. The bend includes a first bend segment and a second bend segment connected at an angle. The end of the first bend segment away from the second bend segment is connected to the housing connection and extends toward the central axis of the housing. The end of the second bend segment away from the first bend segment is connected to the current collector body and extends in a direction away from the electrode assembly.

2. The secondary battery according to claim 1, characterized in that, Along the radial direction of the secondary battery, the end of the second bent segment that connects to the first bent segment is located inside the end of the second bent segment that connects to the current collector body.

3. The secondary battery according to claim 2, characterized in that, Along the radial direction of the secondary battery, the end of the second bent section that connects to the current collector body is located inside the end of the second bent section that connects to the first bent section.

4. The secondary battery according to any one of claims 1 to 3, characterized in that, The length of the first bent segment is a, where 2mm ≤ a ≤ 4mm.

5. The secondary battery according to any one of claims 1 to 3, characterized in that, The length of the second bent segment is b, where 0.5mm ≤ b ≤ 1.5mm.

6. The secondary battery according to any one of claims 1 to 3, characterized in that, A first weak portion extending circumferentially along the secondary battery is provided between the first bending segment and the second bending segment; and / or A second weak portion extending circumferentially along the secondary battery is provided between the second bending section and the current collector body; and / or A third weak section extending circumferentially along the secondary battery is provided between the first bending section and the housing connection portion.

7. The secondary battery according to any one of claims 1 to 3, characterized in that, The current collector body includes a raised portion in the middle, which gradually rises from the outside to the inside towards the electrode assembly along the radial direction of the secondary battery.

8. The secondary battery according to claim 7, characterized in that, The diameter of the outer periphery of the raised portion is D, where 8mm≤D≤37mm.

9. The secondary battery according to claim 7, characterized in that, Along the height direction of the secondary battery, the height of the raised portion protruding from the current collector body is H, where 0.5mm≤H≤1.5mm.

10. An electronic device, characterized in that, Includes a battery pack, said battery pack comprising the secondary battery according to any one of claims 1-9.

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