Secondary battery, battery assembly, and electronic apparatus

Abstract

To provide a secondary battery capable of suppressing damage of a weld part between a collector component inside of a housing and the housing during roll grooving processing of a secondary battery sidewall, a battery assembly, and an electronic apparatus.SOLUTION: A secondary battery includes a housing, an end cap 2, an electrode assembly 3, and a collector component 4. The housing includes an end wall and a sidewall enclosing the end wall. An opening is formed at one side of the sidewall away from the end wall. The sidewall includes a recess 14 which is recessed toward the inside of the housing, a main body part extending between the recess and the end wall, and a transition part between the recess and the main body part. The end cap is disposed at the side of the opening and seals the opening. The electrode assembly is disposed inside of the housing. The collector component includes a collector 41 and a housing connection part 42, and the housing connection part is disposed between the recess and the electrode assembly.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] In the prior art, when processing a secondary battery, generally, current collecting components are disposed inside the housing of the secondary battery, and the current collecting components are welded to the side wall of the housing. Thereafter, roll grooving processing is performed on the side wall of the housing, and finally, the opening is pier-sealed, and an end cap is hermetically disposed at the opening of the housing, thereby completing the mechanical sealing of the secondary battery.

Summary of the Invention

Problems to be Solved by the Invention

[0003] When performing roll grooving processing on the side wall, a curved portion is formed on the side wall. When the curved portion of the side wall partially coincides with the welding position where the current collecting component and the side wall are welded, a large tensile force is generated on the weld mark formed by the welding between the current collecting component and the side wall due to the dent on the side wall during the roll grooving process. However, that large tensile force has a very high possibility of damaging the weld mark. As a result, the connection between the current collecting component and the side wall becomes weak, and this weak connection in turn affects the stability of the electrical connection between the current collecting component and the housing, and ultimately affects the electrical connection performance of the battery.

[0004] In view of the drawbacks of the prior art described above, the present invention provides a secondary battery, a battery assembly, and an electronic device that can solve the above technical problems, that is, the problem that when roll grooving processing is performed on the housing of the battery, there is a very high possibility of damaging the weld mark formed by the welding between the current collecting component and the housing, which affects the stability of the electrical connection between the current collecting component and the housing.

Means for Solving the Problems

[0005] To achieve the above object and other related objects, the present invention provides a secondary battery including a housing, an end cap, an electrode assembly, and a current collecting component. The housing includes an end wall and a side wall surrounding the end wall. An opening is formed on one side of the side wall away from the end wall. The side wall includes a recess formed near the opening and recessed toward the inside of the housing, a main body portion extending between the recess and the end wall, and a transition portion between the recess and the main body portion. The end cap is disposed on the opening side to seal the opening. The electrode assembly is disposed inside the housing. The first tab is disposed on the side facing the opening of the electrode assembly. The current collecting component includes a current collector and a housing connection portion. The current collector is electrically connected to the first tab. The housing connection portion is disposed between the recess and the electrode assembly. Here, the housing connection portion is welded to the main body portion and / or the transition portion.

[0006] In one example of the secondary battery of the present invention, the housing connection portion includes a curved portion extending toward the recess, and the curved portion abuts against and is welded to the main body portion and / or the transition portion.

[0007] In one example of the secondary battery of the present invention, the main body portion has a constant cross-section structure, and an included angle is formed between the curved portion and the main body portion, and the included angle ranges from 0° to 60°.

[0008] In one example of the secondary battery of the present invention, the housing connection portion further includes a folded edge portion, and the folded edge portion is connected to the curved portion and is bent toward the inside of the housing.

[0009] In one example of the secondary battery of the present invention, the housing connection portion is disposed on the outer periphery of the current collector. The housing connection portion includes a groove recessed toward the electrode assembly side. The groove includes a groove bottom wall, an outer groove wall and an inner groove wall connected to both sides of the groove bottom wall. The outer groove wall is connected to the curved portion, and the inner groove wall is connected to the current collector.

[0010] In one example of the secondary battery of the present invention, along the height direction of the secondary battery, the orthographic projection of the current collector and the inner groove wall covers the first tab.

[0011] In one example of the secondary battery of the present invention, along the height direction of the secondary battery, the first tab includes a depression recessed toward one side away from the current collector component, and the groove bottom wall of the groove abuts against the depression.

[0012] In one example of the secondary battery of the present invention, the included angle between the inner groove wall and the groove bottom wall is an obtuse angle.

[0013] In one example of the secondary battery of the present invention, along the height direction of the secondary battery, the distance between the position where the curved portion abuts against the main body portion and the groove bottom wall is d, and 0.3 mm ≤ d ≤ 2.5 mm.

[0014] In one example of the secondary battery of the present invention, along the radial direction of the secondary battery, the width of the groove is W1, the radial depth of the recess is W2, and W1 ≤ 0.7W2.

[0015] In one example of the secondary battery of the present invention, along the height direction of the secondary battery, the distance between the current collector and the groove bottom wall is h2, and d ≥ 0.5h2.

[0016] In one example of the secondary battery of the present invention, the recess includes a pressing portion bent toward the electrode assembly side on the side closer to the axis of the secondary battery of the recess, and the pressing portion at least partially abuts against the current collector.

[0017] In one example of the secondary battery of the present invention, the recess includes a first side wall on the side away from the opening of the recess, and the side away from the center of the opening of the first side wall is connected to the transition portion. Along the height direction of the secondary battery, the distance between the position where the first side wall is connected to the transition portion and the position where the pressing portion abuts against the current collector is h1, and 0.1 mm ≤ h1 ≤ 1 mm.

[0018] In one example of the secondary battery of the present invention, there are a plurality of housing connection portions, and the plurality of housing connection portions are arranged at intervals on the outer periphery of the current collector.

[0019] In one example of the secondary battery of the present invention, the current collector includes a lead-out portion on one side away from the electrode assembly of the current collector, and the lead-out portion is electrically connected to the end cap.

[0020] The present invention further provides a battery assembly including the secondary battery described in any one of the above examples.

[0021] The present invention further provides an electronic device including the battery assembly described above.

Advantages of the Invention

[0022] In the secondary battery of the present invention, by welding and connecting the housing connection portion to the main body portion and / or the transition portion, the welding position between the current collecting component and the housing can be installed so as to be separated from the concave portion. Therefore, the tension and deformation of the welding area between the current collecting component and the housing during the forming process of the concave portion can be reduced. Accordingly, the damage to the welding marks in the welding area can be reduced, and the stability of the welding connection between the current collecting component and the housing can be improved.

Brief Description of the Drawings

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings necessary for describing the embodiments or the prior art are briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. Those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0024]

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Embodiments for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Also, the present invention can be implemented or applied through other different specific embodiments. Each detail in this specification can be variously modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that when there is no contradiction between embodiments, the following embodiments and the features in the embodiments may be combined with each other. Also, it should be understood that the terms used in the embodiments of the present invention are for explaining specific embodiments and do not limit the protection scope of the present invention. For test methods for which specific conditions are not indicated in the following examples, usually, follow conventional conditions or the conditions suggested by various manufacturers.

[0026] When an embodiment provides a numerical range, it should be understood that any two endpoints of each numerical range and any numerical value between the two endpoints can be selected unless otherwise specifically stated in the present invention. Unless otherwise defined, all technical and scientific terms used in the present invention are consistent with the knowledge of the prior art and the description of the present invention by those skilled in the art. They can also be used together with the methods described in the embodiments of the present invention. The devices and materials are the same as or equivalent to any methods, devices, and materials of the prior art for implementing the present invention.

[0027] It should be noted that terms such as "upper", "lower", "left", "right", "middle", "one", etc. cited in this specification are for the convenience of explanation and are not used to limit this specification. Regarding the scope in which the present invention can be implemented, changes or adjustments in relative relationships should also be regarded as within the scope in which the present invention can be implemented unless there are substantial changes in the technical content.

[0028] Referring to FIGS. 1 to 20, the present invention provides a secondary battery 10, a battery assembly 20, and an electronic device 30. In the secondary battery 10, by welding the housing connection portion 42 of the current collecting component 4 to the main body portion 15 and / or the transition portion 16, the welding position between the current collecting component 4 and the housing 1 can be installed so as to be separated from the recess 14. Therefore, the tension and deformation of the welding region between the current collecting component 4 and the housing 1 during the forming process of the recess 14 can be reduced. Accordingly, damage to the weld marks in the welding region can be reduced, thereby improving the stability of the welding connection between the current collecting component 4 and the housing 1.

[0029] Referring to FIGS. 1 to 3, the structure of the secondary battery 10 will be further described. The secondary battery 10 includes a housing 1, an end cap 2, an electrode assembly 3, and a current collecting component 4. A receiving cavity is formed in the housing 1 and is used to accommodate the electrode assembly 3, an electrolyte (not shown), and other components. The housing 1 may have various shapes such as a cylindrical shape or a prismatic shape. The specific dimensions of the housing 1 can be determined based on the specific dimensions of the electrode assembly 3. For example, the diameter is 46 mm, and the height is 80 mm, 95 mm, 120 mm, and other specifications. The housing 1 can be made of various materials such as copper, iron, aluminum, steel, and aluminum alloy. In order to prevent the housing 1 from rusting after long-term use, the surface of the housing 1 may be plated with a layer of a rust-preventive material such as metallic nickel.

[0030] Referring to FIGS. 2 to 5, in one example of the secondary battery of the present invention, the housing 1 has a cylindrical structure. The housing 1 includes an end wall 11 and a side wall 12 surrounding the end wall 11. That is, the housing 1 includes a closed end and an open end. The end wall 11 is the closed end, and the opening 13 on the opposite side of the end wall 11 is the open end. On the side of the side wall 12 facing the opening 13, a recess 14 recessed toward the inside of the housing 1 is formed. On the side wall 12 between the recess 14 and the end wall 11, a main body portion 15 is formed, and the main body portion 15 extends along the height direction of the secondary battery 10. On the side wall 12 between the recess 14 and one end of the main body portion 15 away from the end wall 11, a transition portion 16 is formed. The recess 14 is a concave structure in which the side wall 12 is extruded and deformed toward the inside of the housing 1 under the action of mechanical external force. The recess 14 may be formed by punching the side wall 12 through a forming die, or may be formed by performing roll grooving on the side wall 12 through a roll grooving tool. It is sufficient that the recess 14 on the side wall 12 is a concave structure located in the circumferential direction of the side wall 12. In this example, the recess 14 is formed by performing roll grooving on the side wall 12 through a roll grooving tool. The cross-sectional shape of the recess 14 may be a shape that satisfies the requirements of the user, such as a rectangle, a square, or a trapezoid. On the side wall 12 on the side of the recess 14 close to the opening 13, a further extension portion 17 extending toward the center of the opening 13 is arranged. There is also a connection portion 18 between the extension portion 17 and the recess 14, and the extension portion 17 and the recess 14 are connected via the connection portion 18. It should be noted that the specific dimensions of the recess 14, the extension portion 17, and the connection portion 18 need to be determined according to the dimensional specifications of the secondary battery 10, and thus are not particularly limited in this embodiment. On the side of the recess 14 away from the opening 13, a first side wall 142 is arranged. One end of the first side wall 142 away from the center of the housing 1 is connected to one end of the transition portion 16, and the other end of the transition portion 16 is connected to one end of the main body portion 15 away from the end wall 11. The structural shape of the transition portion 16 may be an arc-shaped structure, an inclined surface structure, or any other structure that can form a smooth transition connection between the main body portion 15 and the recess 14.The main body portion 15 extending between the concave portion 14 and the end wall 11 may have a constant cross-sectional structure or a non-constant cross-sectional structure as long as it can meet the requirements of the user.

[0031] As shown in FIGS. 2 and 3, the electrode assembly 3 is housed in the housing 1. The electrode assembly 3 is a component within the secondary battery 10 that undergoes an electrochemical reaction. The housing 1 can include one or more electrode assemblies 3. The electrode assembly 3 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and usually, a separator is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector, and the positive electrode current collector includes a positive electrode coating region connected to the positive electrode coating region and a positive electrode tab. The positive electrode coating region is coated with the positive electrode active material layer, and the positive electrode tab is not coated with the positive electrode active material layer. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector, and the negative electrode current collector includes a negative electrode coating region connected to the negative electrode coating region and a negative electrode tab. The negative electrode coating region is coated with the negative electrode active material layer, and the negative electrode tab is not coated with the negative electrode active material layer. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material layer includes a positive electrode active material. The positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The material of the negative electrode current collector may be copper, and the negative electrode active material layer can include a negative electrode active material. The negative electrode active material may be carbon or silicon. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the battery cell, the electrode assembly 3 may be covered with an insulating film. The insulating film can be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0032] Referring to FIGS. 2 and 3, in one example of the secondary battery of the present invention, the electrode assembly 3 is sealed within the housing 1. Along the height direction of the secondary battery 10, the electrode assembly 3 is disposed between the end wall 11 and the recess 14, and the recess 14 can limit the axial movement of the electrode assembly 3 between the end wall 11 and the recess 14. The first tab 31 and the second tab are disposed at both ends of the electrode assembly 3 along the height direction of the secondary battery 10, and the first tab 31 and the second tab have opposite polarities. Here, the first tab 31 faces one side of the opening 13, and the first tab 31 is a negative electrode tab. It should be mentioned that in other embodiments, the first tab 31 may be a positive electrode tab, and the second tab may be a negative electrode tab.

[0033] Referring to FIGS. 2 to 4, the end cap 2 is disposed in the opening 13. By sandwiching the outer periphery of the end cap 2 between the extension portion 17, the connection portion 18, and the recess 14 via the seal ring 5, the end cap 2 is sealed and fixed at the opening 13. The current collecting component 4 is disposed in the housing 1 and is located between the end cap 2 and the electrode assembly 3. The current collecting component 4 includes a current collector 41 and a housing connection portion 42. The housing connection portion 42 is disposed on the outer periphery of the current collector 41. The housing connection portion 42 and the current collector 41 are electrically connected. There are many electrical connection methods, for example, welding connection, integral connection, or other methods capable of realizing the electrical connection between the housing connection portion 42 and the current collector 41 as options. In the present embodiment, in order to improve the assembly efficiency, the housing connection portion 42 and the current collector 41 are connected by integral stamping molding. The current collector 41 is electrically connected to the first tab 31. There are various electrical connection methods, for example, welding connection, conductive adhesive bonding, or other methods capable of realizing the electrical connection between the housing connection portion 42 and the first tab 31 as options. In the present embodiment, the current collector 41 and the first tab 31 are connected by welding. Along the height direction of the secondary battery 10, the housing connection portion 42 is located between the first side wall 142 and the electrode assembly 3. One end of the housing connection portion 42 away from the current collector 41 abuts against the inner surface of the main body portion 15 and is welded. Along the height direction of the secondary battery 10, the welding position of the housing connection portion 42 on the main body portion 15 may be higher than the height position of the electrode assembly 3, may be lower than the height position of the electrode assembly 3, or may coincide with the height position of the electrode assembly 3, but the present invention is not limited thereto.

[0034] By abutting one end of the casing connection portion 42 away from the current collector 41 against the inner surface of the main body portion 15 and welding it, the welding position between the casing connection portion 42 and the side wall 12 of the casing 1 can be defined. Therefore, the welding mark can be installed so as to be separated from the recess 14 in the height direction. In this way, during the forming process of the recess 14, for example, by adjusting the roll grooving position during the process of performing roll grooving on the casing 1, the welding mark can be set to be separated from the recess 14 in the height direction. Thereby, the tension and deformation of the welding mark can be reduced, effectively protecting the integrity of the welding mark. As a result, the stability of the welded connection between the current collecting component 4 and the casing 1 can be improved. At the same time, in the radial direction, since the welding position is located at one end of the first side wall 142 away from the center of the casing 1, when the opening position is pier-sealed and a tensile force is generated on the first side wall 142 by the pier-sealing force, the welding position between the current collecting component 4 and the casing 1 does not deform dramatically. In this way, the integrity of the welding mark at the welding position can be further protected, and the stability of the welded connection between the current collecting component 4 and the casing 1 can be further improved.

[0035] It should be noted that in another example of the present invention, one end of the casing connection portion 42 away from the current collector 41 may be abutted against the inner surface of the transition portion 16 and welded, and the advantageous effects of the above-described embodiment can also be achieved by such a configuration. In other embodiments, one end of the casing connection portion 42 away from the current collector 41 may be partially abutted against the inner surface of the main body portion 15 and welded, and partially abutted against the inner surface of the transition portion 16 and welded, and the above-described advantageous effects can also be achieved by such a configuration.

[0036] Referring to FIGS. 3 to 5, in one example of the secondary battery of the present invention, one side of the current collector connection portion 42 away from the current collector 41 includes a curved portion 421. The free end of the curved portion 421 extends toward the concave portion 14. The free end of the curved portion 421 abuts against and is welded to the inner surface of the main body portion 15. The cross-section of the curved portion 421 may be any curved structure such as an inclined surface structure, a curved structure bent multiple times, or a wavy structure. By disposing the curved portion 421, when the current collector connection portion 42 is welded to the side wall 12, the curved portion 421 can relieve the welding stress and reduce the transmission of the welding stress to the current collector 41, thereby improving the stability of the welded connection between the current collector 41 and the first tab 31.

[0037] It should be noted that, in another embodiment of the present invention, the curved portion 421 may be abutted against and welded to the inner surface of the transition portion 16. In this way, the curved portion 421 can also improve the positioning accuracy of the inner surfaces of the curved portion 421 and the main body portion 15 in the radial direction. In other embodiments, the curved portion 421 may be partially abutted against and welded to the inner surface of the transition portion 16 and partially abutted against and welded to the inner surface of the main body portion 15, and such a configuration can also achieve the advantageous effects described in the above embodiments.

[0038] Referring to FIGS. 6 to 8, in one example of the secondary battery of the present invention, the current collector 41 has a disc-shaped structure, the current collector connection portion 42 has an annular structure arranged coaxially with the current collector 41, and an annular curved portion 421 is arranged on one side of the current collector connection portion 42 away from the current collector 41. That is, the curved portion 421 is an integral structure disposed entirely on the outer periphery of the current collector 41. In this way, the overall rigidity and strength of the current collector 41 are increased, the current collecting component 4 is not easily deformed during the welding process, and the stability of the welded connection is improved. At the same time, since the contact area between the curved portion 421 and the side wall 12 of the housing 1 in the circumferential direction is increased, the positioning accuracy is increased, which helps to improve the configuration accuracy of the current collecting component 4.

[0039] Referring to FIGS. 9 to 11, in one example of the secondary battery of the present invention, the current collector 41 has a disk-shaped structure and has a plurality of housing connection portions 42. The plurality of housing connection portions 42 are arranged at intervals on the outer periphery of the current collector 41. Correspondingly, there are also a plurality of curved portions 421, and each curved portion 421 corresponds to one housing connection portion 42. In this way, a region cut between the plurality of housing connection portions 42 in the circumferential direction is formed. With such a structure, the stress generated between the housing connection portion 42 and the side wall 12 can be released, and the stress deformation caused by the current collecting component 4 itself can be reduced.

[0040] Referring to FIGS. 3, 4, 12, and 13, in one example of the secondary battery of the present invention, in order to facilitate the forming process of the main body portion 15, the main body portion 15 adopts a constant cross-sectional structure, and the constant cross-section may be a circular constant cross-sectional structure or a polygonal constant cross-sectional structure, etc. In the present embodiment, the main body portion 15 has a circular constant cross-sectional structure, and the main body portion 15 is a constant cross-sectional structure that extends in a linear direction. That is, the main body portion 15 has a cylindrical structure. There are a plurality of housing connection portions 42, and the plurality of housing connection portions 42 are arranged at intervals on the outer periphery of the current collector 41. The curved portion 421 is arranged corresponding to the housing connection portion 42, and the curved portion 421 abuts against and is welded to the inner surface of the main body portion 15. An included angle α is formed between the curved portion 421 and the main body portion 15, and the included angle α is in the range of 0° to 60°. Preferably, the included angle α is in the range of 30° to 60°. By setting the included angle α between the curved portion 421 and the main body portion 15 in the range of 30° to 60°, on the one hand, an appropriate contact force can be generated between the curved portion 421 and the side wall 12, so that without causing a large contact deformation in the current collector component 4 itself and affecting the configuration accuracy of the current collector component 4 itself, the positioning requirements between the curved portion 421 and the side wall 12 can be satisfied. On the other hand, by forming an included angle between the curved portion 421 and the main body portion 15, an elastic positioning structure can be formed on the side closer to the opening 13 of the current collector component 4, and it can be made to contract toward the center of the housing 1. Therefore, it becomes easier to perform interference-fitting of the current collector component 4 inside the housing 1. In this way, a more stable contact force can be generated between the curved portion 421 and the inner surface of the main body portion 15, so that the welding accuracy and the stability of the welding connection between the current collector component 4 and the housing 1 can be improved.

[0041] During the assembly process of the secondary battery, before the current collector component 4 is placed inside the housing 1, the current collector component 4 is in a free state, and the diameter size of the current collector component 4 may be larger than or equal to the inner diameter of the housing 1. However, preferably, in one embodiment of the secondary battery of the present invention, when the current collector component 4 is in a free state, the diameter size of the current collector component 4 is larger than the inner diameter size of the housing 1. In such a design, during the process of assembling the current collector component 4 into the housing 1, the current collector component 4 can achieve an interference fit between the current collector component 4 and the housing 1 by slight deformation, which helps to improve the placement accuracy of the current collector component 4 inside the housing 1. Referring to FIG. 4, in one example of the secondary battery of the present invention, the housing connection portion 42 also includes a folded edge portion 422. One end of the folded edge portion 422 is connected to the side where the curved portion 421 and the main body portion 15 are in contact and welded, and the other end of the folded edge portion 422 is bent towards the inside of the housing 1. The folded edge portion 422 may be a bevel structure, a curved structure, or any other structure that can block the welding of the curved portion 421. The folded edge portion 422 and the curved portion 421 may be integrally formed or welded, but the present invention is not limited thereto. By arranging the folded edge portion 422 at the welding position of the curved portion 421, a shielding cavity may be formed between the curved portion 421 and the folded edge portion 422. Since the shielding cavity can shield the welding slag generated when the curved portion 421 and the main body portion 15 are welded, it can reduce the scattering of the welding slag inside the housing 1 and reduce the probability of the welding slag entering the inside of the electrode assembly 3, thereby effectively mitigating the damage to the electrode assembly 3. At the same time, since the end of the curved portion 421 is connected to the folded edge portion 422, penetration welding can be employed to weld the curved portion 421 and the main body portion 15, thereby improving the quality of the welded connection.

[0042] Referring to FIGS. 5, 8, and 11, in one example of the secondary battery of the present invention, the housing connection portion 42 further includes a groove 423 recessed toward the electrode assembly 3 side. The groove 423 includes a groove bottom wall 424, which is connected to an outer groove wall 425 and an inner groove wall 426 on both sides of the groove bottom wall 424. The outer groove wall 425 is connected to the curved portion 421, and the inner groove wall 426 is connected to the current collector 41. The cross-sectional shape of the groove 423 may be square, rectangular, or trapezoidal, and the cross-sectional area of the groove 423 is not particularly limited as long as the cross-sectional area of the groove 423 satisfies the component dimension requirements. The connection between the outer groove wall 425 and the curved portion 421 may mean providing an additional curved portion 421 on the outer groove wall 425 and welding or integrally connecting the curved portion 421 to the outer groove wall 425, or may mean that the curved portion 421 is a part of the outer groove wall 425, or may mean that the outer groove wall 425 is the same structural component as the curved portion 421. In this embodiment, the outer groove wall 425 and the curved portion 421 are the same structural component. With such a configuration, the number of components can be reduced, and the assembly efficiency of the current collecting component 4 can be improved. One side of the groove 423 facing the electrode assembly 3 may or may not contact the end face of the electrode assembly 3, but the present invention is not limited thereto. By arranging the groove 423, a height difference is formed between the bottom wall of the groove 423 and the current collector 41, whereby the height of the welding position between the curved portion 421 and the side wall 12 is reduced, and as a result, the height space occupied within the housing 1 is saved, which helps to improve the volume energy density of the secondary battery 10. At the same time, since the groove 423 is close to the curved portion 421, when compressing and positioning the area of the groove 423, the curved portion 421 can be positioned more accurately, so that the welding accuracy of the curved portion 421 can be improved. Furthermore, the configuration of the groove 423 can also relieve the stress when welding the curved portion 421 to the side wall 12, thereby reducing the deformation of the current collecting component 4 itself caused by the welding stress.

[0043] In order to improve the positional accuracy and quality of the welding connection between the current collector component 4 and the side wall 12, the current collector component 4 is usually compressed and positioned during the welding connection between the current collector component 4 and the housing 1. In the present embodiment, since the groove 423 is provided in the current collector component 4, when positioning the current collector component 4, the positioning tool may be a profiling tool that conforms to the shape of the groove 423. When the profiling tool compresses the current collector component 4, the bottom surface of the profiling tool contacts and compresses the groove bottom wall 424 of the groove 423 to realize the compression and positioning of the current collector component 4 in the axial direction. The side wall of the profiling tool may realize the positioning of the current collector component 4 in the radial direction by abutting against the outer groove wall 425 and the inner groove wall 426 of the groove 423, and compress the curved portion 421 and the side wall 12 to ensure the quality of the welding connection between the current collector component 4 and the side wall 12. Naturally, in other embodiments, the positioning tool may not be selected from the profiling tool. As long as the current collector component 4 is positioned and compressed in the axial direction and the radial direction, the specific shape of the positioning tool is not particularly limited.

[0044] Referring to FIGS. 4 and 16, in one example of the secondary battery of the present invention, along the height direction of the secondary battery 10, the orthographic projection of the current collector 41 and the inner groove wall 426 covers the first tab 31. With such a configuration, the first tab 31 can be restricted within the collection cavity formed between the current collector 41 and the inner groove wall 426. In this way, the groove bottom wall 424 can be made to correspond to the region on the end face of the electrode where the first tab 31 is not disposed (i.e., the tab cutting region). Therefore, on the one hand, the configured height of the groove bottom wall 424 on the end face of the electrode assembly 3 can be reduced. Thus, the height of the welding position between the curved portion 421 and the main body portion 15 can be further reduced, and the height space occupied within the housing 1 can be further saved. On the other hand, when the groove bottom wall 424 is brought into close contact with and compressed against the region on the end face of the electrode where the first tab 31 is not disposed, when the pressing force is the same, the positioning accuracy in the height direction is more accurate. Therefore, the positioning accuracy of the groove 423 in the height direction of the secondary battery 10 can be improved, and thereby, the positioning accuracy of the welding connection between the curved portion 421 and the main body portion 15 can be improved.

[0045] Referring to FIGS. 4 and 17, in one example of the secondary battery of the present invention, along the height direction of the secondary battery 10, the first tab 31 includes a depression 311 that is recessed toward the side away from the current collecting component 4, and the groove bottom wall 424 of the groove 423 abuts against the depression 311. The area and shape of the depression 311 correspond to the shape and position of the groove bottom wall 424, and the depth of the depression 311 corresponds to the depth of the groove 423. The side of the groove bottom wall 424 facing the electrode assembly 3 abuts against the side of the depression 311 away from the electrode assembly 3. By disposing the depression 311, on the one hand, rapid positioning between the groove 423 and the depression 311 can be achieved, thereby improving the positioning efficiency of the current collecting component 4 on the end face of the electrode assembly 3. On the other hand, due to the configuration of the depression 311, the gap between the stacked first tabs 31 within the region can be reduced. Therefore, the positioning accuracy when the groove 423 is compressed and positioned in the height direction can be improved.

[0046] Referring to FIG. 16, in one example of the secondary battery of the present invention, one end of the inner groove wall 426 of the groove 423 is connected to the groove bottom wall 424, and the other end of the inner groove wall 426 of the groove 423 is connected to the current collector 41 and is inclined toward the center of the electrode assembly 3. Therefore, the included angle β between the inner groove wall 426 and the groove bottom wall 424 is an obtuse angle. With such a configuration, when the groove 423 is compressed with respect to the end face of the electrode assembly 3, the inner groove wall 426 generates a radial force toward the center of the electrode assembly 3 with respect to the first tab 31. This radial force pushes out the first tab 31 so as to perform lamination compression toward the center of the electrode assembly 3. As a result, the gap between the first tabs 31 in the radial direction decreases, and as a result, the inverted insertion of the first tab 31 during the compression process decreases.

[0047] Referring to FIGS. 4, 5, and 18, in one example of the secondary battery of the present invention, along the height direction of the secondary battery 10, the distance between the position where the curved portion 421 abuts against the main body portion 15 and the outer surface of the groove bottom wall 424 facing the electrode assembly 3 side is d, and 0.3 mm ≤ d ≤ 2.5 mm. For example, the dimension d may be 0.3 mm, 1.5 mm, 2 mm, or 2.5 mm. When the dimension d is smaller than 0.3 mm, the curved portion 421 cannot be properly positioned, which affects the accuracy of the radial positioning between the housing connection portion 42 and the main body portion 15. When the dimension d is larger than 2.5 mm, the dimension d will occupy more height space of the housing 1, which is disadvantageous for improving the volume energy density of the secondary battery 10. Therefore, in the present embodiment, by limiting the dimension d to the range of 0.3 mm to 2.5 mm, the positioning effect of the curved portion 421 and the dimension of the height space occupied in the housing 1 can be appropriately considered.

[0048] Referring to FIGS. 4, 5, and 18, in one example of the secondary battery of the present invention, along the height direction of the secondary battery 10, the distance between one side of the current collector 41 facing the electrode assembly 3 and one side of the groove bottom wall 424 facing the electrode assembly 3 is h2, and h2 ≦ 2d. When the dimension of h2 is large, the groove 423 will occupy a larger height space in the height direction of the secondary battery 10, so the volume energy density of the secondary battery 10 will decrease. In this embodiment, by limiting the dimension h2 to h2 ≦ 2d, the depth of the groove 423 can be limited, thereby reducing the structural space occupied by the groove 423 in the height direction and reducing the influence on the volume energy density of the secondary battery 10.

[0049] Referring to FIGS. 4, 5, and 18, in one example of the secondary battery of the present invention, the recess 14 includes a pressing portion 141 bent toward the electrode assembly 3 on the side of the recess 14 closer to the axis of the secondary battery 10. The pressing portion 141 abuts at least partially against the current collector 41. As long as the pressing portion 141 is at least partially compressed against the current collector 41, the specific dimension of the pressing portion 141 in the radial direction is not particularly limited. By arranging the pressing portion 141, a local region of the recess 14 can be brought into contact with the current collector 41. When the piercing seal force is the same, the compression stress generated between the pressing portion 141 and the current collector 41 becomes larger, thereby improving the positioning of the current collector 41 in the axial direction. At the same time, since the pressing portion 141 is arranged on the recess 14, the position of the pressing portion 141 on the recess 14 can be controlled to control the pressure position between the recess 14 and the current collector 41, thereby further improving the accurate compression and positioning of the current collecting component 4 in the axial direction.

[0050] The pressing amount of the pressing part 141 directly affects the amount of pressure generated by the pressing part 141 and the current collector 41. If the pressing amount is too large, the current collector 41 will be subjected to a greater pressure and be more likely to deform under pressure, thus affecting the dimensional accuracy of the current collector 41. If the pressing amount is too small, the current collector 41 cannot be properly pressed and positioned. Preferably, referring to FIGS. 4, 5, and 18, in one example of the secondary battery of the present invention, along the height direction of the secondary battery 10, the pressing amount of the pressing part 141 is h1, and 0.1 mm ≤ h1 ≤ 1 mm. The dimension h1 is the distance along the height direction of the secondary battery 10 between the position where the first side wall 142 connects the transition part 16 and the position where the pressing part 141 abuts against the current collector 41. In this embodiment, by limiting the dimension h1 to 0.1 mm to 1 mm, without causing large compression and deformation to the current collector 41 itself and affecting the dimensional accuracy, a better compression effect can be obtained between the pressing part 141 and the current collector 41.

[0051] Referring to FIGS. 4, 5, and 18, in one example of the secondary battery of this embodiment, the width of the groove 423 is W1, the radial depth of the recess 14 is W2, and W1 ≤ 0.7W2. When the width of the groove 423 is greater than 0.7W2, there is a possibility that the recess 14 cannot be brought into contact with the current collector 41 during the pierce seal process, thus affecting the positioning effect of the current collecting component 4 and the electrode assembly 3 in the axial direction. In the present invention, by setting W1 ≤ 0.7W2, it can be ensured that the recess 14 can be brought into contact with the current collector 41 and compressed during the pierce seal process. At the same time, since the force-receiving position of the current collector 41 is far from the curved part, it not only does not affect the axial positioning effect of the recess 14 on the electrode assembly 3, but also can reduce the tension and deformation caused by the curved part 421 during the pierce seal process, and can effectively protect the integrity of the weld mark.

[0052] Referring to FIGS. 3, 6, and 9, in one example of the secondary battery of the present embodiment, the current collector 41 includes a lead-out portion 43 on one side away from the electrode assembly 3 of the current collector 41, and the lead-out portion 43 is electrically connected to the end cap 2. The connection between the lead-out portion 43 and the current collector 41 may be an integral connection or a welded connection as long as the electrical connection between the lead-out portion 43 and the current collector 41 is achieved. In the present invention, the lead-out portion 43 and the current collector 41 are integrally stamped and connected. As long as the electrical connection between the lead-out portion 43 and the end cap 2 is achieved, the lead-out portion 43 may be abutted against the central region of the end cap 2 or the end region of the end cap 2, but the present invention is not limited thereto. By arranging the lead-out portion 43 and electrically connecting the lead-out portion 43 to the end cap 2, a current can be generated on the surface of the end cap 2, and thereby, a thin film can be generated on the surface of the end cap 2. This thin film can effectively prevent the erosion of the oxide, and thereby, prevent the corrosion of the surface of the end cap 2. Further, in the present embodiment, in order to evenly distribute the plurality of lead-out portions 43 in the circumferential direction of the current collector 41, the current on the surface of the end cap 2 can be made more uniform, and thereby, a better rust prevention effect on the surface of the end cap 2 can be achieved.

[0053] Referring to FIG. 19, the present invention further provides a battery assembly 20 including the secondary battery 10 described in any one of the above examples. The battery assembly 20 may be a battery module, a battery block, or a battery pack, but the present invention is not limited thereto. In one embodiment of the present invention, the battery assembly 20 includes a box body 21 and at least one secondary battery 10. The box body 21 includes a first box body 211 and a second box body 212. The first box body 211 and the second box body 212 overlap each other to form an accommodation space, and a plurality of secondary batteries 10 are accommodated in the accommodation space. The plurality of secondary batteries 10 can be connected in series and / or in parallel.

[0054] The present invention further provides an electronic device 30, which may be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, a power tool, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. The spacecraft includes airplanes, rockets, space shuttles, spacecraft, etc. The electric toy includes stationary or mobile electric toys, such as game consoles, electric toy cars, electric toy boats, and electric toy airplanes. The power tool includes metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric drivers, electric hammers, impact drills, concrete vibrators, planers, etc. Embodiments of the present invention are not particularly limited to the above-described electronic devices.

[0055] In the electronic device 30 of the present invention, the electronic device 30 includes an operation unit 310 and a battery assembly 20. The operation unit 310 is electrically connected to and supported by the battery assembly 20 to obtain electrical energy for support. The operation unit 310 may be a unit component that can obtain the electrical energy of the battery assembly 20 and perform corresponding operations, such as a blade rotation unit of a fan, a dust collection operation unit of a vacuum cleaner, a wheel drive unit of an electric vehicle, etc. Embodiments of the present invention do not impose special restrictions on the above-described electronic device 30.

[0056] Referring to FIG. 20, in one embodiment of the electronic device 30 of the present invention, the electronic device 30 is a vehicle, the operation unit 310 is the main body of the vehicle, and the battery assembly 20 is fixedly arranged on the main body of the vehicle to provide a driving force for operating the vehicle.

[0057] In the secondary battery of the present invention, by abutting one end of the current collector connection portion away from the current collector against the inner surface of the main body portion and welding, the welding position between the current collector connection portion and the side wall of the housing can be defined. Therefore, the welding mark can be installed so as to be separated from the recess in the height direction. In this way, during the forming process of the recess, for example, by adjusting the roll grooving position during the process of performing roll grooving on the housing, the welding mark can be installed so as to be separated from the recess in the height direction. Thereby, the tension and deformation of the welding mark are reduced, and the integrity of the welding mark is effectively protected. As a result, the stability of the welded connection between the current collecting component and the housing can be improved. At the same time, since the welding position is located at one end of the housing of the first side wall away from the center in the radial direction, when the opening position is sealed by piercing and a tensile force is generated on the first side wall by the piercing sealing force, the welding position between the current collecting component and the housing does not deform dramatically. In this way, the integrity of the welding mark at the welding position can be further protected, and the stability of the welded connection between the current collecting component and the housing can be further improved. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and significance of use. The above-described embodiments are merely examples for explaining the principle and effects of the present invention and do not limit the present invention. Those skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, any equivalent modifications or changes made by those skilled in the art without departing from the spirit and scope of the present invention shall be included in the protection scope of the present invention.

Industrial Applicability

[0058] The secondary battery, battery assembly, and electronic device of the present invention can be applied in the field of battery technology.

Explanation of Reference Numerals

[0059] 10 Secondary battery 1 Housing 11 End wall 12 Side wall 13 Opening 14 Recess 141 Pressing part 142 First side wall 15 Body part 16 Transition part 17 Extension part 18 Connection part 2 End cap 3 Electrode assembly 31 First tab 311 Depression 4 Current collector component 41 Current collector 42 Housing connection part 421 Bending part 422 Folded edge part 423 Groove 424 Groove bottom wall 425 Outer groove wall 426 Inner groove wall 43 Lead-out part 5 Seal ring 20 Battery assembly 21 Box body 211 First box body 212 Second box body 30 Electronic device 310 Operation part

Claims

1. a housing including an end wall and a side wall surrounding the end wall, the side wall having an opening formed on one side thereof remote from the end wall, the side wall including a recess formed near the opening and recessed toward an interior of the housing, a body portion extending between the recess and the end wall, and a transition portion between the recess and the body portion; an end cap disposed on the opening side and sealing the opening; an electrode assembly disposed within the housing, the electrode assembly having a first tab disposed on one side facing the opening; a current collecting part including a current collector electrically connected to the first tab, and a housing connection part disposed between the recess and the electrode assembly; wherein the housing connection portion is welded to the main body portion and / or the transition portion.

2. The secondary battery according to claim 1 , wherein the housing connection portion includes a curved portion extending toward the recess, and the curved portion abuts against and is welded to the main body portion and / or the transition portion.

3. 3. The secondary battery according to claim 2, wherein the main body portion has a constant cross-sectional structure, an included angle is formed between the curved portion and the main body portion, and the included angle is in the range of 0° to 60°.

4. The secondary battery according to claim 2 , wherein the housing connection portion further includes a folded edge portion, the folded edge portion being connected to the curved portion and bent toward the inside of the housing.

5. 3. The secondary battery according to claim 2, wherein the housing connection portion is disposed on an outer periphery of the current collector, the housing connection portion includes a groove recessed toward the electrode assembly side, the groove includes a groove bottom wall, and an outer groove wall and an inner groove wall connected to both sides of the groove bottom wall, the outer groove wall is connected to the curved portion, and the inner groove wall is connected to the current collector.

6. The secondary battery according to claim 5 , wherein an orthogonal projection of the current collector and the inner groove wall covers the first tab along a height direction of the secondary battery.

7. 6. The secondary battery according to claim 5, wherein the first tab includes a recess recessed toward one side away from the current collecting component along a height direction of the secondary battery, and the bottom wall of the groove abuts against the recess.

8. 6. The secondary battery according to claim 5, wherein an included angle between the inner groove wall and the groove bottom wall is an obtuse angle.

9. 6. The secondary battery according to claim 5, wherein a distance between the position where the curved portion abuts on the main body portion and the bottom wall of the groove is d, and 0.3 mm≦d≦2.5 mm, along a height direction of the secondary battery.

10. 6. The secondary battery according to claim 5, wherein the width of the groove is W1, the depth of the recess in the radial direction of the secondary battery is W2, and W1≦0.7W2.

11. 10. The secondary battery according to claim 9, wherein a distance between the current collector and the bottom wall of the groove along a height direction of the secondary battery is h2, and d≧0.5h2.

12. 2. The secondary battery according to claim 1, wherein the recess includes a pressing portion bent toward the electrode assembly on one side of the recess closer to the axis of the secondary battery, the pressing portion at least partially abutting the current collector.

13. 13. The secondary battery of claim 12, wherein the recess includes a first side wall on one side of the recess away from the opening, one side of the first side wall away from the center of the opening is connected to the transition portion, and a distance h1 between a position where the first side wall connects to the transition portion and a position where the pressing portion abuts against the current collector along a height direction of the secondary battery is 0.1 mm≦h1≦1 mm.

14. The secondary battery according to claim 1 , wherein there are a plurality of housing connectors, the plurality of housing connectors being spaced apart on an outer periphery of the current collector.

15. The secondary battery according to claim 1 , wherein the current collector includes a lead portion on one side of the current collector away from the electrode assembly, the lead portion being electrically connected to the end cap.

16. A battery assembly comprising the secondary battery according to any one of claims 1 to 15.

17. 17. An electronic device comprising the battery assembly of claim 16.

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