Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery. The secondary battery comprises a top cover and a pole arranged on the top cover, the electrode assembly comprises a battery cell main body and a lug protruding out of the battery cell main body, and a riveting hole is formed in the lug; and the rivet is connected with the pole and penetrates through the riveting hole to rivet the pole and the tab. The utility model aims to provide a secondary battery, a battery pack and an electronic device so as to improve the energy density and safety of the secondary battery.

Description

Technical Field

[0001] The utility model relates to a secondary battery, a battery pack and an electronic device. Background Art

[0002] For decades, with the rise of new energy vehicles and electrochemical energy storage stations, the development of lithium-ion batteries has received much attention. During the production process of lithium-ion batteries, it is necessary to connect the wound or laminated and hot-pressed electrode assembly / rolled battery cell (JR) to the pole column on the top cover plate. At present, most batteries use riveting, screws, or ultrasonic welding to connect the tab of the electrode assembly to the adapter plate, and then use laser welding to connect the pole column to the adapter plate; there are also some batteries that cancel the use of the adapter plate in order to improve space utilization and energy density, and directly connect the tab to the pole column by laser welding. Summary of the Utility Model

[0003] Aiming at the problems existing in the related art, the purpose of the utility model is to provide a secondary battery, a battery pack and an electronic device to improve the energy density and safety of the secondary battery.

[0004] To achieve the above purpose, the utility model provides a secondary battery, including: a top cover and a pole column arranged on the top cover; an electrode assembly, including a cell main body and a tab protruding from the cell main body, and a riveting hole is arranged on the tab; a rivet, connecting the pole column and passing through the riveting hole to rivet the pole column and the tab.

[0005] In some embodiments, the rivet is arranged on the side of the pole column facing the electrode assembly.

[0006] In some embodiments, the pole column and the rivet are an integral part.

[0007] In some embodiments, the pole column includes a positive pole column and a negative pole column, the tab includes a positive tab and a negative tab, the positive pole column is riveted to the positive tab by a rivet, and the negative pole column is riveted to the negative tab by another rivet.

[0008] In some embodiments, the secondary battery includes one or more electrode assemblies, and the pole column is connected to a corresponding number of rivets to connect the tabs of one or more electrode assemblies.

[0009] In some embodiments, the rivet is a solid structure or a hollow structure. When projected along the direction from the electrode assembly to the pole column, the shape of the outer boundary of the rivet is one or a combination of a circle, an ellipse, a square, a rectangle, a rhombus, and a triangle.

[0010] In some embodiments, the edge area of the rivet is welded to the pole column and the tab.

[0011] In some embodiments, the electrode assembly is a wound or laminated electrode assembly.

[0012] An embodiment of the present application further provides a battery pack, including the secondary battery of any one of the above.

[0013] An embodiment of the present application further provides an electronic device, including the above battery pack.

[0014] The beneficial technical effects of the present utility model are as follows:

[0015] In the embodiment of the present application, rivets are used to rivet the tab and the terminal post, without involving the use of a transition piece, which can effectively reduce the weight of the secondary battery and improve the battery energy density; and it can avoid the safety risk caused by the welding slag of the tab and the terminal post in conventional ultrasonic welding or laser welding to the electrode assembly, improving the safety performance of the secondary battery; in addition, the embodiment of the present application uses the riveting method, which can effectively improve the situation of tab cracking when welding the tab and the terminal post in the prior art, improve the excellent rate of the secondary battery, and reduce the production cost of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Shows an electrical device according to an embodiment of the present application.

[0018] Figure 2 Shows an electrode assembly according to an embodiment of the present application.

[0019] Figure 3 Shows a bottom view of a top cover and the structure thereon according to an embodiment of the present application.

[0020] Figure 4 Shows a front view of a top cover and the structure thereon according to an embodiment of the present application.

[0021] Figure 5 Shows a partial structure of a secondary battery according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To better understand the spirit of the embodiments of the present application, the following further describes it in conjunction with some preferred embodiments of the present application.

[0023] Embodiments of the present application will be described in detail below. Throughout the specification of the present application, components that are the same or similar and components having the same or similar functions are denoted by like reference numerals. The embodiments of the drawings described herein are illustrative, diagrammatic, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0024] As used herein, the terms "substantially", "essentially", "substantially", and "about" are used to describe and account for minor variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs exactly and instances in which the event or circumstance occurs very nearly.

[0025] In this specification, unless specifically specified or limited otherwise, relative terms such as: "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "higher", "horizontal", "vertical", "above", "below", "upper", "lower", "top", "bottom" and their derivatives (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are for convenience of description only and do not require the present application to be constructed or operated in a particular direction.

[0026] For ease of description, "first", "second", "third", etc. may be used herein to distinguish different components of a figure or a series of figures. "First", "second", "third", etc. are not intended to describe corresponding components.

[0027] As described in the background art, when the tab is connected to the terminal by a connecting piece, the connecting piece occupies a certain space and weight in the battery, resulting in a low energy density of the battery; and when the tab is directly laser welded to the inner surface of the terminal, the welding area of the tab is prone to cracking, affecting the battery performance and consistency. In addition, in conventional production, metal debris is easily generated during the process of connecting the tab to the terminal by ultrasonic welding or laser welding, remaining inside the electrode assembly, which will pose a fatal safety risk to the electrode assembly.

[0028] The present utility model provides an electronic device 1000. For the convenience of description in the following embodiments, the electronic device 1000 is taken as an example of a vehicle for illustration. Refer to Figure 1, a battery pack 1002 is provided inside the vehicle. The battery pack 1002 can be arranged at the bottom, head or tail of the vehicle body 1001. The battery pack 1002 can be used for power supply of the vehicle. For example, the battery pack 1002 can serve as the operating power source of the vehicle. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain power support. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc., but is not limited thereto. The working part is the vehicle body, and the battery pack 1002 is arranged at the bottom of the vehicle body and provides power support for the running of the vehicle or the operation of the electrical components inside the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the working part can obtain the electric energy of the battery pack 1002 and is a unit component that performs corresponding work, such as the fan blade rotation unit of a fan, the dust suction working unit of a vacuum cleaner, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and a railway electric tool, such as an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, a planer, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned electronic device 1000.

[0029] Figure 2 The electrode assembly 120 according to an embodiment of the present application is shown. Figure 3 The bottom view of the top cover 172 and the structure thereon according to an embodiment of the present application is shown (i.e., the inner side of the cover plate 172 facing the electrode assembly 120 is shown). Figure 4 The front view of the top cover 172 and the structure thereon according to an embodiment of the present application is shown. Figure 5 The partial structure of the secondary battery 100 according to an embodiment of the present application is shown. Figure 5 The top cover 172 and the two electrode assemblies 120 are shown unfolded to rivet the tab 122 to the terminal post 50, and the bottom view angle of the top cover 172 is shown. After the riveting is completed, the tab 122 is bent at the position connected to the cell body 124 so that the two electrode assemblies 120 are combined and bundled together, and then placed into the battery housing.

[0030] The secondary battery 100 includes a battery case, an electrode assembly 120, and a terminal post 50. The battery case includes a top cover 172, an end wall, and a side wall surrounding the end wall. As long as a stable sealing and electrical connection relationship can be formed, the connection between the end wall and the side wall can be achieved in various ways. For example, it can be integrally stamped, integrally cast, or separately welded. The surrounding of the side wall is not limited and can be cylindrical or prismatic, or it can surround along any other closed-loop contour that can match the end wall. An accommodation cavity is formed inside the battery case for accommodating the electrode assembly 120, the electrolyte, and other necessary battery components. Specifically, the diameter of the battery case can be determined according to the specific size of the electrode assembly 120. The material of the battery case can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. To prevent the battery case from rusting during long-term use, an anti-rust material such as metallic nickel can also be plated on the surface of the battery case.

[0031] The electrode assembly 120 is accommodated within the battery case. The electrode assembly 120 is a component in the secondary battery 100 where electrochemical reactions occur. One or more electrode assemblies 120 may be included within the battery case. The electrode assembly 120 is a wound or laminated electrode assembly, including stacked and / or wound positive electrode plates, a first separator, negative electrode plates, and a second separator. The positive electrode plate includes a positive current collector and a positive active material layer coated on the positive current collector. A first coated area coated with the positive active material layer and a first uncoated area not coated with the positive active material layer are formed on the positive current collector. The first coated area and the first uncoated area are arranged along the height direction of the electrode assembly 120. The first uncoated area extends to outside the separator towards one end in the height direction of the secondary battery 100 and forms a bent positive electrode tab 125. The negative electrode plate includes a negative current collector and a negative active material layer coated on the negative current collector. A second coated area coated with the negative active material layer and a second uncoated area not coated with the negative active material layer are formed on the negative current collector. The second coated area and the second uncoated area are arranged along the height direction of the electrode assembly 120. The second uncoated area also extends to outside the separator towards one end in the height direction of the secondary battery 100 and forms a bent negative electrode tab 26. The first separator and the second separator are disposed between the positive electrode plate and the negative electrode plate to isolate the positive active material layer and the negative active material layer. Taking the lithium-ion secondary battery 100 as an example, the material of the positive current collector may be aluminum. The positive active material layer includes a positive active material, and the positive active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. The material of the negative current collector may be copper. The negative active material layer includes a negative active material, and the negative active material may be carbon or silicon, etc. The base material of the first separator and the second separator may be PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the battery cell, an insulating film may also be coated outside the battery cell, and the insulating film may be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0032] Further, in the present utility model, the positive electrode tab 125 and the negative electrode tab 126 face and are respectively electrically connected to the positive electrode post 55 and the negative electrode post 56 on the top cover 172. The top cover 172 is hermetically installed on the side wall of the battery case; the outer edge shape of the top cover 172 corresponds to the shape of the side wall opening, and the installation method of the top cover 172 includes but is not limited to mechanical sealing or welding sealing.

[0033] See Figures 2 to 5, embodiments of the present application provide a secondary battery 100. The secondary battery 100 includes a battery housing and an electrode assembly 120 accommodated in the battery housing. The battery housing includes a top cover 172 and a pole column 50 provided on the top cover 172; the electrode assembly 120 includes a battery cell main body 124 and a tab 122 protruding from the battery cell main body 124, and a riveting hole 1220 is provided on the tab 122; a rivet 10 connects the pole column 50 and passes through the riveting hole 1200 to rivet the pole column 50 and the tab 122. Embodiments of the present application use the rivet 10 to rivet the tab 122 and the pole column 50, without involving the use of a transition piece, which can effectively reduce the weight of the secondary battery 100 and improve the battery energy density; and it can avoid the safety risk caused by the welding slag of the conventional ultrasonic welding or laser welding of the tab and the pole column to the electrode assembly 120, and improve the safety performance of the secondary battery 100; in addition, embodiments of the present application use the riveting method, which can effectively improve the situation of tab cracking when welding the tab and the pole column in the prior art, improve the excellent rate of the secondary battery 100, and reduce the production cost of the secondary battery 100.

[0034] See Figures 3 to 5 , the rivet 10 is provided on the side of the pole column 50 facing the electrode assembly 120 to pass through the riveting hole 1220 on the tab 122 of the electrode assembly 120 and rivet the tab 122. The pole column 50 and the rivet 10 can be an integral part, or the rivet can also be connected to the pole column 50 through other processes (such as welding). At this time, there is no need to worry about the problem of welding slag, because it is not yet connected to the electrode assembly 120 at this time, and the welding slag will not remain in the battery housing and affect the electrode assembly 120. The pole column 50 includes a positive pole column 55 and a negative pole column 56, the tab 122 includes a positive tab 125 and a negative tab 126, the positive pole column 55 is riveted to the positive tab 125 through the rivet 10, and the negative pole column 56 is riveted to the negative tab 126 through another rivet 10. One or more (such as but not limited to Figure 5 the two shown) electrode assemblies 120 can be accommodated in the battery housing, and the pole column 50 is connected to a corresponding number of rivets 10 to connect the tabs 122 of one or more electrode assemblies 120.

[0035] See Figure 3 , when projected along the direction from the electrode assembly 120 to the pole column 50, the shape of the outer boundary of the rivet 10 is one or a combination of a circle, an ellipse, a square, a rectangle, a rhombus, a triangle, etc. The rivet 10 can also be other shapes, and the shape of the riveting hole 1220 on the tab 122 matches the rivet 10. See Figure 5 , the rivet 10 is a hollow structure. After the rivet 10 passes through the riveting hole 1222, the edge turns outwards to clamp the tab 122. The rivet 10 can also be a staple-shaped solid structure, and the nail rod protruding after passing through the riveting hole 1220 is upset by the axial force to form a nail head to clamp the tab 122.

[0036] In other embodiments, the edge region of the rivet 10 can be welded (such as laser welding or resistance welding) to the pole column 50 and the tab 122 to enhance its riveting strength.

[0037] After the positive electrode plate, the negative electrode plate, and the separator are wound (or laminated) and hot-pressed, an electrode assembly 120 is formed. For the electrode assembly 120 that has undergone hot pressing (or hot-pressing pairing), the tabs 122 are first shaped by ultrasonic pre-welding. After the tabs 122 are shaped, riveting holes 1220 matching the rivets 10 are formed in the tabs 122. After the riveting holes 1220 in the tabs 122 are opened, the riveting holes 1220 in the tabs 122 are sleeved on the rivets 10 connected to the pole column 50 of the top cover 172, and then corresponding riveting operations are performed to connect the electrode assembly 120 and the top cover 172 by riveting. The lower plastic 180 is located inside the top cover 172 and is made of an insulating material to insulate the electrode assembly 120; the explosion-proof valve 182 is provided on the top cover 172 for exhausting the secondary battery 100. When exhausting, the gas can break through the explosion-proof valve 182 to prevent the secondary battery 100 from exploding, thereby improving the safety performance of the secondary battery 100. The liquid injection hole 186 is located on the top cover 172. After Figure 5 the structures shown are combined together and then placed into the battery case, electrolyte is injected into the secondary battery 100 through the liquid injection hole 186.

[0038] An embodiment of the present application further provides a battery pack 1002, including the secondary battery 100 of any one of the above, and the battery pack 1002 can have the beneficial effects described above regarding the secondary battery 100.

[0039] An embodiment of the present application further provides an electronic device 1000, including the battery pack 1002 of any one of the above, and the electronic device 1000 can have the beneficial effects described above regarding the secondary battery 100 and the battery pack 1002.

[0040] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A secondary battery, characterized in that: include: A top cover and a pole arranged on the top cover; The electrode assembly comprises a battery cell body and a pole ear protruding from the battery cell body, wherein the pole ear is provided with a rivet hole; A rivet is connected to the pole and passes through the riveting hole to rivet the pole and the pole ear.

2. The secondary battery according to claim 1, characterized in that: The rivet is disposed on a side of the pole facing the electrode assembly.

3. The secondary battery according to claim 1, characterized in that: The pole and the rivet are an integral piece.

4. The secondary battery according to claim 1, characterized in that: The pole column includes a positive pole column and a negative pole column, the pole tab includes a positive pole tab and a negative pole tab, the positive pole column is riveted to the positive pole tab via the rivet, and the negative pole column is riveted to the negative pole tab via another rivet.

5. The secondary battery according to claim 1, characterized in that: The secondary battery includes one or more electrode assemblies, and a corresponding number of rivets are connected to the electrode posts to connect the electrode tabs of the one or more electrode assemblies.

6. The secondary battery according to claim 1, characterized in that: The rivet is a solid structure or a hollow structure. When projected in the direction from the electrode assembly to the pole, the shape of the outer boundary of the rivet is one or a combination of circle, ellipse, square, rectangle, diamond, triangle.

7. The secondary battery according to claim 1, characterized in that: The edge area of ​​the rivet is welded together with the pole and the pole ear.

8. The secondary battery according to claim 1, characterized in that: The electrode assembly is a wound or laminated electrode assembly.

9. A battery pack, characterized in that: A secondary battery comprising any one of claims 1 to 8.

10. An electronic device, characterized in that: A battery pack comprising the battery pack of claim 9.

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