Secondary battery
By using laser welding and connecting plate design, the problem of foreign objects entering the electrode assembly during ultrasonic welding was solved, enabling direct connection between the tab and the electrode post, reducing the risk of short circuit in the secondary battery, improving processing efficiency, and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- AESC DYNAMICS TECHNOLOGY (HEBEI) LTD
- Filing Date
- 2025-05-06
- Publication Date
- 2026-06-12
AI Technical Summary
During the welding process of the tabs and terminals of a secondary battery, the frictional vibrations generated by ultrasonic welding may cause foreign objects to enter the electrode assembly, leading to safety hazards and short circuit risks.
Laser welding is used to connect the tabs and the electrode post, and the tabs are constrained by connecting pieces to prevent foreign objects from ultrasonic welding from entering the electrode assembly, thus achieving direct connection of the tabs.
This effectively prevents foreign objects from entering the electrode assembly during ultrasonic welding, reduces the risk of short circuits in secondary batteries, improves processing efficiency, and saves processing costs.
Smart Images
Figure CN224355410U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a secondary battery. Background Technology
[0002] In the field of new energy power batteries, the application of secondary batteries is becoming increasingly widespread. For example, secondary batteries (such as lithium-ion batteries) can be used in electronic devices such as vehicles, energy storage, mobile phones, tablets, wearable devices, power banks, e-cigarettes, digital products, power tools, power units, and energy storage devices. Secondary batteries typically consist of a casing and electrode assemblies. The electrode assembly includes a positive electrode, a first separator, a negative electrode, and a second separator, which are stacked sequentially to form a wound electrode assembly or a stacked electrode assembly, and then encapsulated within the casing.
[0003] However, when welding the tabs to the terminals on the cover of the secondary battery, the tabs are usually ultrasonically pre-welded to form a weld mark, and then the tabs and terminals are laser-welded in the ultrasonic weld mark area. The foreign matter generated by the ultrasonic friction vibration of ultrasonic welding poses a safety hazard. Utility Model Content
[0004] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery that at least avoids foreign objects generated by ultrasonic friction vibration during ultrasonic welding from entering the electrode assembly, realizes direct connection of the electrode tabs, and constrains the electrode tabs through connecting pieces to prevent short circuit of the secondary battery.
[0005] To achieve the above objectives, this utility model provides a secondary battery, comprising: a cover plate assembly, the cover plate assembly including a cover plate and an electrode post disposed on the cover plate; an electrode assembly including an electrode body and electrode tabs extending from the electrode body, with multiple electrode tabs stacked to form an electrode tab group; and a connecting piece, the connecting piece including a first part and a second part stacked, and the first part and the second part being connected by a bending portion; wherein, the electrode tab group is disposed between the first part and the second part, the first part is connected to the electrode post, and the second part and the electrode tab group are laser welded to the first part.
[0006] In some embodiments, the second part, the tab assembly, and the first part are laser-welded to the pole post.
[0007] In some embodiments, the bent portion is provided with at least one through hole or groove.
[0008] In some embodiments, the ratio of the length of the laser-printed electrode extending in the second direction to the length of the electrode post in the second direction is in the range of 0.5 to 0.9, wherein the second direction is perpendicular to the first direction, which is the direction along the thickness of the electrode body, in the lower surface plane of the cover plate facing the electrode assembly.
[0009] In some embodiments, at least one tab in the tab assembly abuts against or bends within the bend.
[0010] In some embodiments, in a second direction, the first portion has a width greater than that of the electrode post and the tab has a width less than that of the first portion, and the second direction is a direction perpendicular to the thickness of the electrode body within the surface of the cover plate facing the electrode assembly.
[0011] In some embodiments, the length of the second portion in the second direction is less than the length of the tab assembly, and / or the length of the second portion in the first direction is less than the length of the first portion, wherein the second direction is perpendicular to the first direction in the lower surface plane of the cover plate facing the electrode assembly, and the first direction is the direction along the thickness of the electrode body.
[0012] In some embodiments, the secondary battery further includes a first insulating tape that at least covers the laser-welded stamping on the second portion and extends toward the root of the tab assembly.
[0013] In some embodiments, the first insulating tape extends to the root of the tab assembly and then to the electrode body; or, the secondary battery further includes a second insulating tape, one end of which overlaps with the first insulating tape, and the other end of which extends to the root of the tab assembly and then to the electrode body.
[0014] In some embodiments, the tab assembly includes a positive tab assembly and a negative tab assembly extending from the electrode assembly, and the connecting piece includes a positive connecting piece and a negative connecting piece. The positive connecting piece is made of aluminum, and the negative connecting piece is made of copper. The positive terminal of the cover plate assembly is connected to the positive tab assembly through the positive connecting piece, and the negative terminal of the cover plate assembly is connected to the negative tab assembly through the negative connecting piece. The thickness of the connecting piece is in the range of 0.05 mm to 0.25 mm.
[0015] The beneficial technical effects of this utility model are at least as follows:
[0016] In this embodiment, the tab assembly is disposed between the first part and the second part. The first part is connected to the electrode post, and the second part and the tab assembly are laser welded to the first part. This at least prevents foreign objects generated by ultrasonic friction vibration during ultrasonic welding from entering the electrode assembly, thus achieving direct connection of the tabs. Furthermore, the tabs are constrained by the connecting piece to prevent short circuits in the secondary battery. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 A schematic diagram of an electronic device, using a vehicle as an example, is shown.
[0019] Figure 2A A perspective view of a secondary battery according to an embodiment of this application is shown.
[0020] Figure 2B A top view schematic diagram of a secondary battery according to an embodiment of this application is shown.
[0021] Figure 3 It shows Figure 2A An enlarged schematic diagram of region A in the middle.
[0022] Figure 4 An exploded view of a cover plate assembly and connecting piece according to some embodiments of this application is shown.
[0023] Figure 5A A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0024] Figure 5B A top view schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0025] Figure 5C A side view schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0026] Figure 6 It shows Figure 5A Enlarged schematic diagram of region B in the middle.
[0027] Figure 7 It shows Figure 5C A magnified view of region C in the middle.
[0028] Figure 8 A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0029] Figure 9A A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0030] Figure 9B A top view schematic diagram of a secondary battery according to some embodiments of this application is shown.
[0031] Figure 10 It shows Figure 9A A magnified diagram of region D in the middle.
[0032] Figure 11 A three-dimensional schematic diagram of a cover plate assembly and a connecting piece according to some embodiments of this application is shown.
[0033] Figure 12 An exploded view of a cover plate assembly and connecting piece according to some embodiments of this application is shown.
[0034] Figure 13 A three-dimensional schematic diagram of a cover plate assembly and a connecting piece according to some embodiments of this application is shown.
[0035] Figure 14 An exploded view of a cover plate assembly and connecting piece according to some embodiments of this application is shown.
[0036] Figure 15 A three-dimensional schematic diagram of a cover plate assembly and a connecting piece according to some embodiments of this application is shown.
[0037] Figure 16 An exploded view of a cover plate assembly and connecting piece according to some embodiments of this application is shown.
[0038] Figure 17 A three-dimensional schematic diagram of a cover plate assembly and a connecting piece according to some embodiments of this application is shown.
[0039] Figure 18 It shows Figure 9A A magnified view of region E in the middle.
[0040] Figure 19 A three-dimensional schematic diagram of a connecting piece and a pole according to some embodiments of this application is shown.
[0041] Figure 20 A three-dimensional schematic diagram of a connecting piece according to some embodiments of this application is shown.
[0042] Figure 21 A three-dimensional schematic diagram of a connecting piece according to some embodiments of this application is shown.
[0043] Figure 22 A three-dimensional schematic diagram of a connecting piece and a pole according to some embodiments of this application is shown.
[0044] Figures 23 to 26 A schematic diagram illustrating the assembly process of a secondary battery according to some embodiments of this application is shown. Detailed Implementation
[0045] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.
[0046] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.
[0047] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.
[0048] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.
[0049] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.
[0050] Figure 1 A schematic diagram of an electronic device is shown, using vehicle 1000 as an example. See also Figure 1 For ease of explanation, the following embodiments use a vehicle 1000 as an example of an electronic device. However, it is not difficult to understand that the electronic device provided in this application is not limited to a vehicle; the electronic device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, a power tool, etc.
[0051] A battery pack 1002 can be installed inside the vehicle 1000, and the battery pack 1002 can be located at the bottom of the vehicle body 1001 (e.g., Figure 1 (As shown) or at the head, tail, or any other suitable location. The battery pack 1002 can be used to power the vehicle 1000; for example, the battery pack 1002 can serve as the operating power source or drive power source for the vehicle 1000. The battery pack 1002 may include multiple secondary batteries and a housing assembly that houses the multiple secondary batteries.
[0052] It should be understood that the secondary battery in this application can be of various shapes, such as cylindrical, flat, cuboid, or other shapes, and the embodiments of this application do not limit this. On the other hand, the secondary battery in this application can be a lithium-ion battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, etc., and the embodiments of this application do not limit this either.
[0053] Figure 2A A perspective view of a secondary battery according to an embodiment of this application is shown. Figure 2B A top view schematic diagram of a secondary battery according to an embodiment of this application is shown. Figure 3 It shows Figure 2A An enlarged view of region A in the diagram. For ease of understanding, Figure 2A and Figure 2B The image shows an electrode assembly 120 and a cover assembly 202, wherein the cover assembly 202 is not in the assembled state of the secondary battery. It is understood that when the cover assembly 202 is assembled, the second portion 232 of the connecting piece 230 faces the electrode assembly 120. In some embodiments, the opposite ends of the casing of the secondary battery of this application may each have openings, and the cover assembly 202 is respectively disposed at the openings and seals the receiving cavity. The casing and the cover assembly 202 are components that jointly house the electrode assembly 120 and the electrolyte. The casing can be made of any of a variety of available materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The casing may be in the shape of a flat cuboid with openings on opposite sides, and together with the cover assembly 202, defines a receiving cavity in which the electrode assembly 120 is disposed. The cover assembly 202 of the secondary battery has terminals 208, which can be connected to the tabs 121 of the electrode assembly 120.
[0054] In some embodiments, the electrode assembly 120 may include a positive electrode, a first separator, a negative electrode, and a second separator stacked sequentially to form the electrode assembly 120. The electrode assembly 120 also includes a tab group 121, which is formed by stacking a plurality of tabs 1213 extending from the electrode assembly 120. In some embodiments, the tab group 121 includes a positive tab group 1211 and a negative tab group 1212 respectively disposed on opposite sides of the secondary battery. An electrolyte may be located between the positive electrode, the first separator, the negative electrode, and the second separator.
[0055] The positive electrode in a secondary battery may include a positive current collector and a positive active material layer coated on both sides of the positive current collector. The portion of the positive current collector not coated with the positive active material layer constitutes the positive electrode tab. The negative electrode may include a negative current collector and a negative active material layer coated on both sides of the negative current collector. The portion of the negative current collector not coated with the negative active material layer constitutes the negative electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector may be aluminum, and the positive active material layer may include a positive active material, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The material of the negative current collector may be copper, and the negative active material layer may include a negative active material, such as carbon or silicon. In some embodiments, the materials of the first separator and the second separator may be, for example, PP (polypropylene) or PE (polyethylene). The positive and negative electrode sheets will be described in further detail in the following illustrations.
[0056] See also Figure 2A , Figure 2B and Figure 3In some embodiments, the secondary battery of this application includes: a cover plate assembly 202, which includes a cover plate 206 and an electrode post 208 disposed on the cover plate 206; an electrode assembly 120, which includes an electrode body 122 and electrode tabs 1213 extending from the electrode body 122, wherein a plurality of electrode tabs 1213 are stacked to form an electrode tab group 121; a connecting piece 230, which includes a first portion 231 and a second portion 232 stacked together, and the first portion 231 and the second portion 232 are connected by a bending portion 233; the electrode tab group 121 is disposed between the first portion 231 and the second portion 232, the first portion 231 is connected to the electrode post 208, and the second portion 232 and the electrode tab group 121 are laser welded to the first portion 231. In some embodiments, the connecting piece 230 may also be referred to as a protective piece, which is used to prevent the electrode tabs 1213 from directly contacting the laser and penetrating the electrode tabs 1213. According to embodiments of this application, the first portion 231 and the second portion 232 can be straight segments of the connecting piece 230, while the bent portion 233 is a bent segment connecting these two straight segments. It is understood that by laser welding the first portion 231, the second portion 232, and the tab assembly 121, the problem of foreign matter generated by ultrasonic friction vibration entering the electrode plate of the electrode assembly 120 is at least avoided when ultrasonic welding is used. Additionally, at least the connecting piece 230 enables a direct electrical connection between the tab assembly 121 and the terminal post 208, and the connecting piece 230, configured with the bent portion 233, constrains the tabs 1213 in the tab assembly 121, preventing the tabs 1213 from contacting the casing and causing a short circuit in the secondary battery. In other words, electrode sheets with multiple equal-length tabs 1213 become electrode assembly 120 after being wound or stacked. Multiple tabs 1213 of the positive electrode sheet or multiple tabs 1213 of the negative electrode sheet are stacked and bundled together to form tab group 121. Within the same tab group 121, the multiple tabs 1213 may have varying lengths. Furthermore, the first portion 231, the second portion 232, and the bending portion 233 of the connecting piece 230 clamp the tabs 1213 in the tab group 121. Due to the presence of the bending portion 233, longer tabs 1213 can be bent or abut against the bending portion 233, while shorter tabs 1213 remain unaffected. Alternatively, in some embodiments, at least one tab 1213 in the tab group 121 abuts against the bending portion 233 or is bent within the bending portion 233. However, it is also possible that none of the tabs 1213 in the tab assembly 121 abut against the bending portion 233 or bends within the bending portion 233. According to the structure of the connecting piece 230 in the embodiments of this application, at least the need to cut the tabs 1213 to obtain better length consistency when the tabs 1213 in the tab assembly 121 have different lengths can be reduced. Furthermore, in some embodiments, it is not necessary to cut the tabs 1213 of different lengths.
[0057] In some embodiments, the second portion 232, the tab assembly 121, and the first portion 231 are welded to the pole post 208 via laser solder joint 240. It is understood that using laser solder joint 240 to weld the connecting piece 230 and the tab assembly 121 to the pole post 208 eliminates the need for ultrasonic pre-welding of the tab 1213 in the tab assembly 121 and also eliminates the need for a traditional adapter piece, reducing the internal resistance between the tab 1213 and the pole post 208. However, the first portion 231 of the connecting piece 230 can also be fixed to the pole post 208 in other ways, such as riveting. See also... Figure 2A , Figure 2B and Figure 3 , Figure 3 The diagram also shows that the connection between the first portion 231 of the connecting piece 230 and the pole post 208 is achieved by constructing the pole post 208 and the first portion 231 of the connecting piece 230 as a single unit. The connection method between the connecting piece 230 and the pole post 208 will be described further later.
[0058] Figure 4 An exploded view of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 4 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 4 The diagram shows the cover plate assembly 202 and the connecting piece 230. In some embodiments, a groove 235 is formed on the connecting piece 230 (also in...). Figure 3 (As shown in the diagram) to facilitate the formation of the bending portion 233, when the bending portion 233 is formed, the groove 235 is located on the bending portion 233. The cover plate assembly 202 may include: a pole post 208, a lower plastic 207, a cover plate 206, an upper plastic 205, and a riveting member 204. The pole post 208 is fixed to the cover plate 206 by the lower plastic 207, the upper plastic 205, and the riveting member 204. One end of the pole post 208 penetrates the lower plastic 207, the cover plate 206, the upper plastic 205, and the riveting member 204, and the other end is connected to the connecting piece 230. In some embodiments, the connecting piece 230 is welded to the pole post 208, and the part of the connecting piece 230 connected to the pole post 208 is the first part 231, which can also be understood as the first part 231 of the connecting piece being welded to the lower surface of the pole post 208, which will be described in detail later.
[0059] See now. Figure 2A , Figure 2B , Figure 3 as well as Figure 4 . Figure 2A The diagram shows the first direction F, the second direction S, and the third direction T. Figure 2BThe second direction S and the third direction T are shown. In some embodiments, the first direction F is along the thickness of the electrode body 122; the second direction S is in the lower surface plane of the cover plate 206 facing the electrode assembly 120, perpendicular to the first direction F; and the third direction T is the direction of the cover plate 206 towards the electrode assembly 120 in the assembled state. As described above, Figure 2A and Figure 2B The illustration shows the cover assembly 202 not in an assembled state within the secondary battery, and only one cover assembly 202 connected to the positive electrode tab group 1221 is shown, omitting the housing. In this case, the cover assembly 202 connected to the positive electrode tab group 1221 can be referred to as the positive electrode cover assembly, and the connecting piece 230 connecting the positive electrode tab group 1221 and the positive electrode cover assembly can also be referred to as the positive electrode connecting piece. When the cover assembly 202 is assembled into the secondary battery, the cover assembly 202 is folded upwards, for example, along the first direction F. At this time, the second portion 232 of the connecting piece 230 faces the electrode body 122, and the laser solder mark 240 also faces the electrode body 122, thus the cover assembly 202 is assembled into the secondary battery. In some embodiments, combined with... Figure 2A , Figure 2B , Figure 3 ,as well as Figure 4 When the cover plate assembly 202 is assembled to the secondary battery, the ratio of the length of the laser weld 240 extending in the second direction S to the length of the electrode post 208 in the second direction S is in the range of 0.5 to 0.9. If the ratio of the length of the laser weld 240 to the length of the electrode post 208 in the second direction S is too low, for example, below 0.5, the connection strength of the laser weld 240 is insufficient; if the ratio is too high, for example, above 0.9, the laser weld 240 will be too close to the lower plastic 207 during laser welding, which may easily cause the lower plastic 207 to melt. Furthermore, in some embodiments, when the cover plate assembly 202 is assembled to the secondary battery, in the second direction S, the first portion 231 has a width greater than the width of the electrode post 208, and the tab 1213 has a width smaller than the width of the first portion 231. The second direction S is the direction perpendicular to the thickness of the electrode body 122 within the surface of the cover plate 206 facing the electrode assembly 120. Alternatively, when the width of the pole post 208 in the second direction S is small, the cross-section of the pole post 208 is narrower than the tab 1213 of the tab assembly 121. In this case, the area of the first part 231 of the connecting piece 230 is increased. More preferably, the width of the first part 231 of the connecting piece 230 is strengthened in the second direction S so that the width of the first part 231 is greater than the width of the pole post 208 and the tab 1213, so as to enhance the protective effect of the connecting piece 230 on the tab 1213.
[0060] Figure 5A A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown. Figure 5B A top view schematic diagram of a secondary battery according to some embodiments of this application is shown. Figure 5C A side view schematic diagram of a secondary battery according to some embodiments of this application is shown. Figure 6 It shows Figure 5A Enlarged schematic diagram of region B in the middle. Figure 7 It shows Figure 5C A magnified view of region C in the middle. Similar to... Figure 2A , Figure 5A , Figure 5B and Figure 5C The cover assembly 202 shown is not in an assembled state within the secondary battery, and only one cover assembly 202 connected to the positive electrode tab group 1221 is shown, omitting the housing. In this case, the cover assembly 202 connected to the positive electrode tab group 1221 can be referred to as the positive electrode cover assembly, and the connecting piece 230 connecting the positive electrode tab group 1221 and the positive electrode cover assembly can also be referred to as the positive electrode connecting piece. See also Figure 5A , Figure 5B , Figure 5C , Figure 6 as well as Figure 7 In some embodiments, the secondary battery further includes a first insulating tape 260, which at least covers the laser solder mark 240 on the second portion 322 of the connecting piece 320. It is understood that this arrangement of the first insulating tape 260 at least prevents solder slag generated during laser cutting to form the laser solder mark 240 from falling into the electrode body 122 of the secondary battery. The first insulating tape 260 may extend towards the root of the tab 1213 without contacting the electrode body 122; however, the first insulating tape 260 may also extend to the electrode body 122 after reaching the root of the tab 1213. It can also be understood that the root of the tab 1213 is the root of the tab assembly 121. Figure 6 and Figure 7 The diagram shows that the connection between the first portion 231 of the connecting piece 230 and the pole post 208, as described above, is achieved by constructing the pole post 208 and the first portion 231 of the connecting piece 230 as a single unit. However, the connection between the first portion 231 of the connecting piece 230 and the pole post 208 can be achieved in any other reasonable manner. Figure 8 A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown. Similar to Figure 2 and... Figure 5A , Figure 8 The cover assembly 202 shown is not in an assembled state within the secondary battery, and only one cover assembly 202 connected to the positive electrode tab group 1221 is shown, omitting the housing. In this case, the cover assembly 202 connected to the positive electrode tab group 1221 can be referred to as the positive electrode cover assembly, and the connecting piece 230 connecting the positive electrode tab group 1221 and the positive electrode cover assembly can also be referred to as the positive electrode connecting piece. See also Figure 8 In some embodiments, the secondary battery further includes a second insulating tape 270, one end of which overlaps with the first insulating tape 260, and the other end of which extends to the root of the tab 1213 of the tab assembly 121 and then to the electrode body 122. This arrangement of the second insulating tape 270 at least strengthens the outermost layer of tabs 1213 in the tab assembly 121, preventing the tabs 1213 from breaking.
[0061] Figure 9A A three-dimensional schematic diagram of a secondary battery according to some embodiments of this application is shown. Figure 9B A top view schematic diagram of a secondary battery according to some embodiments of this application is shown. Figure 10 It shows Figure 9A A magnified view of region D in the middle. Similar to the aforementioned... Figure 2A , Figure 2B , Figure 5A as well as Figure 5B , Figure 9A and Figure 9B The cover assembly 202 shown is not in an assembled state within the secondary battery. Only a cover assembly 202 connected to the positive electrode tab group 1221 is shown, and the housing is omitted. In this case, the cover assembly 202 connected to the positive electrode tab group 1221 can be referred to as the positive electrode cover assembly, and the connecting piece 230 connecting the positive electrode tab group 1221 and the positive electrode cover assembly can also be referred to as the positive electrode connecting piece. See also Figure 9A , Figure 9B Figure 9C and Figure 10 In some embodiments, with the cover assembly 202 assembled to the secondary battery, the length of the second portion 232 of the connecting piece 230 in the second direction S is less than the length of the tab assembly 121, and / or, in the first direction F, the length of the second portion 232 of the connecting piece 230 is less than the length of the first portion 231 of the connecting piece 230. Preferably, the length of the second portion 232 of the connecting piece 230 in the first direction F is less than the length of the tab assembly 121. This arrangement of the second portion 232 of the connecting piece 230 at least ensures that the tabs 1213 of the tab assembly 121 are exposed relative to the second portion 232 of the connecting piece 230, facilitating the application of pressure from above by the processing tool to limit the tabs 1213 during secondary battery processing. Furthermore, the smaller area of the second portion 232 of the connecting piece 230 also saves material; and the arrangement of the tabs 1213 of the tab assembly 121 is visualized.
[0062] It is understood that, according to some embodiments of this application, the tab assembly 121 includes a positive tab assembly 1211 and a negative tab assembly 1212 extending from the electrode assembly 120, and the connecting piece 230 includes a positive connecting piece and a negative connecting piece. The positive electrode post of the cover plate assembly 202 is connected to the positive tab assembly 1211 via the positive connecting piece, and the negative electrode post of the cover plate assembly 202 is connected to the negative tab assembly 1212 via the negative connecting piece. It is understood that, as illustrated in the figures of this application, the positive tab assembly 1211 and the negative tab assembly 1212 are respectively disposed on opposite sides of the electrode assembly 120, and the positive and negative electrode posts are also respectively disposed on the two cover plate assemblies 202 located on opposite sides of the electrode assembly 120. The tab assembly 121 includes a positive electrode tab assembly 1211 and a negative electrode tab assembly 1212 located on opposite sides of the electrode assembly 120. The cover plate assembly 202 connected to the positive electrode tab assembly 1211 via a connecting piece 230 can be referred to as the positive electrode cover plate assembly, and the cover plate assembly 202 connected to the negative electrode tab assembly 1212 via a connecting piece 230 can be referred to as the negative electrode cover plate assembly. However, in some embodiments of this application, the positive electrode tab assembly 1211 and the negative electrode tab assembly 1212 may be located on the same side of the electrode assembly 120 and connected to the positive electrode post and negative electrode post disposed on the same cover plate assembly 202 via different connecting pieces 230. It is understood that the connecting piece 230 connecting the positive electrode tab assembly 1211 to the positive electrode post is a positive connecting piece, and the connecting piece 230 connecting the negative electrode tab assembly 1212 to the negative electrode post is a negative connecting piece. Furthermore, in some embodiments, the positive electrode connecting piece is made of aluminum, the negative electrode connecting piece is made of copper, and the thickness of the connecting piece 230 is in the range of 0.05mm to 0.25mm. If the thickness of the connecting piece 230 is set reasonably, for example within the above-mentioned thickness range, then it is at least convenient to bend the connecting piece 230; if the connecting piece 230 is set too thin, for example less than 0.05mm, then the protective strength of the connecting piece 230 for the tab 1213 is reduced; if the connecting piece 230 is set too thick, for example greater than 0.25mm, then the connecting piece 230 is not easy to bend.
[0063] Figure 11 A three-dimensional schematic diagram of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. It can be understood that... Figure 11 Corresponding to Figure 4 An exploded view of the cover plate assembly 202 and the connecting piece 230. Note that... Figure 11 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 4 and Figure 11In some embodiments, a groove 235 is formed on the connecting piece 230 to facilitate the formation of the bending portion 233. When the bending portion 233 is formed, the groove 235 is located on the bending portion 233, and the connecting piece 230 is welded to the lower surface of the pole post 208 of the cover plate assembly 202. The connecting piece 230 may not completely cover the lower surface of the pole post 208. At least one groove 235 may be provided, and it is also feasible to provide multiple grooves 235 to facilitate bending.
[0064] Figure 12 An exploded view of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Figure 13 A three-dimensional schematic diagram of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 12 and Figure 13 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. Figure 12 and Figure 13 Correspondingly, it can be understood that in some embodiments, similar to Figure 4 and Figure 11 A groove 235 is formed on the connecting piece 230 to facilitate the formation of the bending portion 233. When the bending portion 233 is formed, the groove 235 is located on the bending portion 233. The connecting piece 230 can be constructed as an integral part with the pole post 208 to realize the connection between the connecting piece 230 and the pole post 208.
[0065] Figure 14 An exploded view of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Figure 15 A three-dimensional schematic diagram of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 14 and Figure 15 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. Figure 14 and Figure 15 Correspondingly, in some embodiments, at least one through hole 236 is formed on the connecting piece 230 to facilitate the formation of the bending portion 233, and the through hole 236 is located on the bending portion 233 when the bending portion 233 is formed. The connecting piece 230 is welded to the lower surface of the pole post 208 of the cover plate assembly 202, and the connecting piece 230 may not completely cover the lower surface of the pole post 208.
[0066] Figure 16 An exploded view of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Figure 17 A three-dimensional schematic diagram of the cover plate assembly 202 and the connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 16 and Figure 17The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. Figure 16 and Figure 17 Correspondingly, in some embodiments, at least one through hole 236 is formed on the connecting piece 230 to facilitate the formation of the bending portion 233. When the bending portion 233 is formed, the through hole 236 is located on the bending portion 233. The connecting piece 230 can be integrally constructed with the pole post 208 to realize the connection between the connecting piece 230 and the pole post 208.
[0067] Figure 18 It shows Figure 9A A magnified view of region E in the middle. See also: Figure 9A and Figure 18 In some embodiments, the second portion 232 of the connecting piece 230 near the inner edge 2321 of the tab assembly 121 may be rounded. In some embodiments, the second portion 232 of the connecting piece 230 near the inner edge 2321 of the tab assembly 121 may be a rounded transition. It is understood that, as described above... Figure 9A The illustration shows the cover assembly 202 not in the assembled state within the secondary battery. When the cover assembly 202 is assembled into the secondary battery, the cover assembly 202 is folded upwards, for example, along the first direction F. In this case, the excessively sharp inner edge 2321 may damage the tabs 1213. As described above, the arrangement of the second portion 232 near the inner edge 2321 of the tab assembly 121 can effectively prevent damage to the tabs 1213 near the inner edge 2321 when the cover assembly 202 is assembled into the secondary battery. However, the above-described arrangement of the inner edge 2321 of the second portion 232 is not only applicable to… Figure 9A The embodiments shown are not applicable to the various connecting pieces 230 used in the embodiments of this application.
[0068] As illustrated in the figure above, the connecting piece 230 before bending has a relatively regular profile, such as a trapezoidal or rectangular profile. However, the connecting piece 230 before bending can also have other suitable shape profiles.
[0069] Figure 19 A three-dimensional schematic diagram of the connecting piece 230 and the pole post 208 according to some embodiments of this application is shown. Note that... Figure 19 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 19 The connecting piece 231 has a notch 239 that extends into a groove 235. Together, the notch 239 and the groove 235 define the connecting piece 230 as two parts with different areas. Furthermore, in some embodiments, the groove 235 is offset from the pole post 208.
[0070] Figure 20 A three-dimensional schematic diagram of a connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 20 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 20 The connecting piece 231 has a notch 239 that does not extend into the groove 235. The notch 239 and the groove 235 together define the connecting piece 230 as two parts with different areas.
[0071] Figure 21 A three-dimensional schematic diagram of a connecting piece 230 according to some embodiments of this application is shown. Note that... Figure 21 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 20 The connecting piece 231 has a rectangular outline and a groove 235 that defines the connecting piece 230 into two parts.
[0072] Figure 22 A three-dimensional schematic diagram of the connecting piece 230 and the pole post 208 according to some embodiments of this application is shown. Note that... Figure 22 The diagram shows the state of the connecting piece 230 when it is not bent, at which point the bend 233 is not formed. See also... Figure 22 The connecting piece 231 has a notch 239 that extends into a groove 235. The notch 239 and the groove 235 together define the connecting piece 230 as two portions with different areas. Furthermore, in some embodiments, the groove 235 is offset from the pole post 208. Unlike... Figure 19 The connecting piece 230 and the pole post 208 shown are not integral parts. Figure 22 The connecting piece 230 and the pole post 208 shown are integrally formed as a single piece.
[0073] Figures 23 to 26 A schematic diagram illustrating the assembly process of a secondary battery according to some embodiments of this application is shown. Figure 23 In the process, a portion of the connecting piece 230 is bent and the roller 550 is abutted against the lower surface of the bent portion of the connecting piece 230, and the electrode assembly 121 formed by the stacked electrode tabs 1213 is overlapped on the upper surface of the other unbent portion of the connecting piece 230. Figure 24 The diagram illustrates the continued bending of the connecting piece 230 via roller 550; however, the bending methods for the connecting piece 230 include, but are not limited to, using a folding knife, a contour block, or other reasonable methods. Figure 25 In the process, after the connecting piece 230 is completely bent by the roller 550, the upper surface of the second part 232 of the connecting piece 230 is flattened and pressed by the roller 550, and the electrode tab 1213 in the electrode tab assembly 121 held therein by the first part 231 and the second part 232 can also be flattened and pressed. Figure 26In the process, the connecting piece 230 is pressed together by the pressure head 560, and the tab assembly 121, the first part 231, and the second part 232 are welded together by the laser 570. Figure 26 The diagram illustrates the weld mark 240 formed by laser 570 welding.
[0074] It is understood that the ultrasonic pre-welding of electrode tabs in traditional assembly methods can be eliminated through the assembly process described above, thereby avoiding foreign matter generated by ultrasonic friction vibration. Furthermore, by simultaneously welding the electrode tabs 121 on both sides of the electrode assembly 120, the processing efficiency of the secondary battery can be significantly improved. Additionally, it is understood that the assembly process described above allows for the assembly of the secondary battery without moving the assembly position of the electrode assembly 120. Consequently, since this assembly process avoids frequent and repeated handling and transfer of the electrode assembly 120, it can save factory space, reduce equipment investment, and lower the processing cost of the secondary battery.
[0075] Embodiments of this application also provide an electronic device 1000, which includes a secondary battery as described above, and the electronic device 1000 can have the beneficial effects described above regarding the secondary battery.
[0076] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A secondary battery, characterized in that, include: A cover plate assembly, the cover plate assembly including a cover plate and a pole disposed on the cover plate; An electrode assembly includes an electrode body and tabs extending from the electrode body, with multiple tabs stacked together to form a tab group; A connecting piece, the connecting piece comprising a first part and a second part stacked together, and the first part and the second part being connected by a bending portion; The electrode assembly is disposed between the first part and the second part, the first part is connected to the electrode post, and the second part and the electrode assembly are laser welded to the first part.
2. The secondary battery according to claim 1, wherein, The second part, the tab assembly, and the first part are welded to the pole post by laser soldering.
3. The secondary battery according to claim 1, wherein, The bent portion is provided with at least one through hole or groove.
4. The secondary battery according to claim 2, wherein, The ratio of the length of the laser-printed electrode extending in the second direction to the length of the electrode post in the second direction is in the range of 0.5 to 0.9, wherein, in the lower surface plane of the cover plate facing the electrode assembly, the second direction is perpendicular to the first direction, which is the direction along the thickness of the electrode body.
5. The secondary battery according to claim 1, wherein, At least one of the tabs in the tab assembly abuts against the bending portion or bends within the bending portion.
6. The secondary battery according to claim 1, wherein, In a second direction, the first portion has a width greater than that of the electrode post and the tab has a width less than that of the first portion, and the second direction is a direction perpendicular to the thickness of the electrode body within the surface of the cover plate facing the electrode assembly.
7. The secondary battery according to claim 1, wherein, In the second direction, the length of the second portion is less than the length of the tab assembly, and / or in the first direction, the length of the second portion is less than the length of the first portion, wherein, in the lower surface plane of the cover plate facing the electrode assembly, the second direction is perpendicular to the first direction, and the first direction is the direction along the thickness of the electrode body.
8. The secondary battery according to claim 1 further includes a first insulating tape, the first insulating tape at least covering the laser solder mark on the second portion and extending toward the root of the tab assembly.
9. The secondary battery according to claim 8, wherein, The first insulating tape extends to the root of the tab assembly and then to the electrode body; or, it further includes a second insulating tape, one end of which overlaps with the first insulating tape, and the other end of which extends to the root of the tab assembly and then to the electrode body.
10. The secondary battery according to any one of claims 1 to 9, characterized in that, The electrode assembly includes a positive electrode assembly and a negative electrode assembly extending from the electrode assembly. The connecting piece includes a positive connecting piece and a negative connecting piece. The positive connecting piece is made of aluminum, and the negative connecting piece is made of copper. The positive electrode post of the cover plate assembly is connected to the positive electrode assembly through the positive connecting piece, and the negative electrode post of the cover plate assembly is connected to the negative electrode assembly through the negative connecting piece. The thickness of the connecting piece is in the range of 0.05 mm to 0.25 mm.