Battery cell and secondary battery

Abstract

This application provides a battery cell and a secondary battery. The battery cell includes: an electrode assembly comprising a main body and tabs extending from the main body; an adapter plate comprising a connecting body portion and two connecting portions, the two connecting portions being located at one end of the main body portion and stacked, the width of the connecting portions being greater than the width of the tabs; the tabs are welded between the two connecting portions to form a first solder mark area on the tabs; the two connecting portions are welded to form two second solder mark areas, the two second solder mark areas being located on both sides of the tabs along their width direction. The battery cell and secondary battery provided by this application have a simple structure, are easy to manufacture, are safe and reliable, and have strong stability.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell and a secondary battery. Background Technology

[0002] With the rise of new energy vehicles and electrochemical energy storage stations, higher requirements have been placed on the structure of lithium-ion battery cells. Common lithium-ion battery cells can be classified into pouch cells, cylindrical cells, and aluminum-cased cells according to their assembly form. Among them, pouch cells have attracted much attention due to their high energy density and strong safety. However, the electrode components of existing pouch cells are prone to localized cracking and warping after being connected to the adapter plate, which affects the cell's performance. Therefore, there is an urgent need for a battery cell with better stability. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a battery cell and a secondary battery to solve the related problems mentioned in the background art.

[0004] A first aspect of this application provides a battery cell, comprising: an electrode assembly including a body and tabs extending from the body; an adapter plate including a connected body portion and two connecting portions, the two connecting portions being located at one end of the body portion and stacked, the width of the connecting portions being greater than the width of the tabs; the tabs being soldered between the two connecting portions and forming a first solder mark area on the tabs; the two connecting portions being soldered to form two second solder mark areas, the two second solder mark areas being located on both sides of the tabs along their width direction.

[0005] Furthermore, the first solder area is a strip-shaped structure extending along the width direction of the electrode assembly, and the second solder area is a strip-shaped structure extending along the length direction of the electrode assembly.

[0006] Furthermore, the distance between the first solder area and the edge of the tab is greater than or equal to 2 mm, and the distance between the second solder area and the tab is greater than or equal to 4 mm and less than or equal to 10 mm.

[0007] Furthermore, the thicknesses of the two connecting portions are not equal.

[0008] Furthermore, two overlapping adhesive tapes are attached to the adapter piece, the width of the adhesive tapes being greater than the width of the connecting portion, the connecting portion being located between the two adhesive tapes, and the adhesive tapes covering the first soldering area and the second soldering area.

[0009] Furthermore, one side of the tape is attached to the top of the body.

[0010] Furthermore, the adapter piece is provided with a sealant layer, which is located between the main body and the connecting part.

[0011] Furthermore, the sealant layer is located on the side of the tape away from the connector, and the orthographic projection of the tape on the adapter piece at least partially covers the orthographic projection of the sealant layer on the adapter piece.

[0012] Furthermore, the sealant layer is disposed in the same layer as the tape, and the edge of the sealant layer abuts against or is spaced apart from the edge of the tape.

[0013] A second aspect of this application provides a secondary battery, including the cell described in the first aspect above.

[0014] As can be seen from the above description, the battery cell and secondary battery provided in this application include: an electrode assembly comprising a main body and tabs extending from the main body; an adapter plate comprising a connecting body portion and two connecting portions, the two connecting portions being located at one end of the main body portion and stacked, the width of the connecting portions being greater than the width of the tabs; the tabs are welded between the two connecting portions and a first solder mark area is formed on the tabs; the two connecting portions are welded to form two second solder mark areas, the two second solder mark areas being located on both sides of the tabs along their width direction. By setting two connecting portions to cover the tabs for welding, the stability of the connection can be effectively improved, eliminating the need for additional protective plates and avoiding the problem of lifting; by forming a first solder mark area on the tabs and two second solder mark areas outside the tabs, the binding of the tabs is increased, greatly reducing the risk of tab cracking. This battery cell and secondary battery have a simple structure, are easy to manufacture, are safe and reliable, and have strong stability. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a side view of a battery cell in an embodiment of this application.

[0017] Figure 2 for Figure 1 A magnified cross-sectional view of point A in the middle.

[0018] Figure 3 This is a schematic diagram of the structure of an adapter piece in an embodiment of this application.

[0019] Figure 4 This is a partial structural diagram of the adapter plate and electrode assembly in an embodiment of this application.

[0020] Figure 5This is a partial structural diagram of the connection between the connecting part and the electrode tab in an embodiment of this application.

[0021] Reference numerals: 1. Electrode assembly; 1-1. Main body; 1-2. Electrode tab; 1-3. First soldering area; 2. Adapter piece; 2-1. Main body; 2-2. Connecting part; 2-3. Second soldering area; 3. Adhesive tape; 4. Sealing adhesive layer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0023] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. In existing battery cells, when connecting electrode components and adapter plates, the tabs are connected to single-layer adapter plates by ultrasonic welding or other methods. During the welding process, protective plates are used for welding protection, and after welding, tape is applied for insulation.

[0024] In the process of developing this application, it was discovered that these types of battery cells are prone to the following problems: First, when welding the tabs to the adapter plates using ultrasonic welding, the tabs at the edge of the solder joint are prone to cracking, affecting the cell performance and consistency. Second, during ultrasonic welding, the protective sheet around the perimeter is prone to lifting, and the lifted portion of the protective sheet may puncture the aluminum-plastic film of the battery cell, causing safety performance issues and reliability failures. Third, as the lifespan of the pouch cell decreases, the electrode assembly will continuously expand, and the tensile force on the tabs in the welding area will also increase, easily causing the tabs to break and affecting the cell performance. Fourth, the adhesive tape at the tabs, due to long-term immersion in the electrolyte, will continuously decrease in adhesion, and the tape may separate and migrate, causing insulation failure.

[0025] The following describes specific embodiments in conjunction with the appendix. Figures 1 to 5 The technical solution of this application will be further described in detail.

[0026] In some embodiments of this application, a battery cell is provided, comprising: an electrode assembly 1, including a main body 1-1 and tabs 1-2 extending from the main body 1-1; an adapter piece 2, including a connected body portion 2-1 and two connecting portions 2-2, the two connecting portions 2-2 being located at one end of the body portion 2-1 and stacked, the width of the connecting portions 2-2 being greater than the width of the tabs 1-2; the tabs 1-2 being welded between the two connecting portions 2-2 and forming a first solder mark area 1-3 on the tabs 1-2; the two connecting portions 2-2 being welded to form two second solder mark areas 2-3, the two second solder mark areas 2-3 being located on both sides of the tabs 1-2 along its width direction.

[0027] like Figure 1 The diagram shows a schematic of a battery cell. The battery cell includes an electrode assembly 1 and an adapter plate 2. In the diagram, the L direction is the length direction of the electrode assembly 1, and the H direction is the thickness direction of the electrode assembly 1.

[0028] like Figure 2 As shown, Figure 1 A magnified structural diagram at point A. Electrode assembly 1 includes a main body 1-1 and tabs 1-2. The main body 1-1 is, for example, a stacked body or a wound body, and the tabs 1-2 are, for example, a positive tab or a negative tab.

[0029] like Figure 3 The diagram shows a schematic of an adapter piece 2. The adapter piece 2 includes a main body 2-1 and two connecting parts 2-2, made of, for example, metal. The two connecting parts 2-2 are located at one end of the main body 2-1 and are stacked. They can be manufactured by stacking multiple layers of metal sheets and then hot-pressing them in different areas, or by welding or other methods to connect the connecting parts 2-2 to the main body 2-1. The specific method is not limited.

[0030] like Figure 4 The diagram shows the structure of the adapter 2 and the electrode assembly 1. The W direction in the diagram represents the width of the electrode assembly 1. The width of the connecting portion 2-2 is greater than the width of the tab 1-2, and the tab 1-2 is located between the two connecting portions 2-2, so that the two connecting portions 2-2 can partially cover the tab 1-2.

[0031] The two connecting parts 2-2 are welded, for example, by ultrasonic welding, friction welding, or laser welding. The welding forms a first solder mark area 1-3 in the area where the tab 1-2 is located. The shape of the first solder mark area 1-3 is, for example, rectangular, elliptical, triangular, straight, or curved. The connection between the tab 1-2 and the adapter piece 2 is achieved through the first solder mark area 1-3.

[0032] Two second solder areas 2-3 are formed outside the area where the tab 1-2 is located. The shape of the second solder areas 2-3 is, for example, rectangular, elliptical, triangular, straight, or curved. The two second solder areas 2-3 are located on both sides of the tab 1-2 along the W direction, which can effectively improve the stability of the connection, increase the restraint of the tab 1-2 to a certain extent, and reduce the risk of the tab 1-2 tearing caused by the expansion of the electrode assembly 1.

[0033] Because this connection method has two connecting parts 2-2, there is no need to use a protective sheet during welding, which avoids the problem of the protective sheet lifting up, and simplifies the manufacturing process and reduces the production cost of the battery cell.

[0034] This battery cell has a simple structure and is easy to manufacture. It can effectively improve defects such as cracking and warping of the tabs 1-2, and has strong stability, safety and reliability. The consistency of the battery cell is greatly improved.

[0035] In some embodiments, the first solder area 1-3 is a strip structure extending along the width direction of the electrode assembly 1, and the second solder area 2-3 is a strip structure extending along the length direction of the electrode assembly 1.

[0036] like Figure 5 The diagram shows a structural schematic of the connection portion 2-2 and the tab 1-2 mating. The first soldering area 1-3 is a strip-shaped structure that extends along the W direction, which increases the mating width between the tab 1-2 and the connection portion 2-2, ensuring the stability of the soldering.

[0037] The second soldering area 2-3 is also a strip structure, and the strip structure extends along the L direction. This can further improve the connection effect of the connecting part 2-2, prevent the ends from lifting, and also increase the cooperation effect between the tab 1-2 and the connecting part 2-2.

[0038] In some embodiments, the distance between the first solder area 1-3 and the edge of the tab 1-2 is greater than or equal to 2 mm, and the distance between the second solder area 2-3 and the tab 1-2 is greater than or equal to 4 mm and less than or equal to 10 mm.

[0039] The distance between the first soldering area 1-3 and the edge of the tab 1-2 is greater than or equal to 2mm. The distance is, for example, 2mm, 3mm or 4mm, etc., and there is no specific limitation. While ensuring the fit width between the tab 1-2 and the connecting part 2-2, the welding effect can be ensured and the unevenness of the welding surface can be avoided, which would affect the subsequent performance of the battery cell.

[0040] The distance between the second soldering area 2-3 and the tab 1-2 is greater than or equal to 4mm and less than or equal to 10mm. The distance can be, for example, 4mm, 6mm, 8mm or 10mm, etc., and there is no specific limitation. This can ensure the welding effect, avoid the tab 1-2 being reduced due to excessive distance, and also avoid the welding flatness being affected by excessive distance and the end of the connection 2-2 being warped due to excessive distance.

[0041] In some embodiments, the thicknesses of the two connecting portions 2-2 are not equal.

[0042] One connecting part 2-2 can be thicker, and the other connecting part 2-2 can be thinner. For example, the thickness of one connecting part 2-2 can be 50% to 80% of the thickness of the other connecting part 2-2, without any specific limitation. While ensuring the structural strength of the adapter piece 2, the thinner connecting part 2-2 can face the welding equipment (e.g., the welding head) during welding. This is more conducive to welding processing, and the thicker connecting part 2-2 can provide support, improving the welding effect.

[0043] In some embodiments, two overlapping adhesive tapes 3 are attached to the adapter piece 2. The width of the adhesive tapes 3 is greater than the width of the connecting portion 2-2. The connecting portion 2-2 is located between the two adhesive tapes 3. The adhesive tapes 3 cover the first soldering area 1-3 and the second soldering area 2-3.

[0044] like Figure 3 As shown, two opposing adhesive tapes 3 are stacked on the adapter piece 2. The adhesive tapes 3 are, for example, pressure-sensitive adhesive. The width of the adhesive tapes 3 is greater than the width of the connecting part 2-2, and both connecting parts 2-2 are located between the two adhesive tapes 3. Thus, after the connecting part 2-2 and the tab 1-2 are welded, as shown... Figure 4 As shown, the tape 3 can adhere to and cover the connecting part 2-2, and cover the first soldering area 1-3 and the second soldering area 2-3 for protection. It can also prevent debris or metal fragments during the welding process from falling into the electrode assembly 1, puncturing the diaphragm or causing an internal short circuit.

[0045] In some embodiments, the thickness of the tape 3 is 0.1 mm to 1.0 mm, and the thickness of the body portion 2-1 is 0.1 mm to 2.0 mm.

[0046] The thickness of the tape 3 is 0.1mm to 1.0mm, such as 0.1mm, 0.5mm, 0.7mm or 1.0mm, which can balance protection and space utilization. The thickness of the body part 2-1 is 0.1mm to 2.0mm, such as 0.1mm, 0.5mm, 1.0mm or 2.0mm, which can ensure connection and conductivity.

[0047] In some embodiments, one side of the tape 3 is attached to the top of the body 1-1.

[0048] like Figure 2 and Figure 4 As shown, one side of the tape 3 is attached to the top of the body 1-1 of the electrode assembly 1, which can improve the connection stability of the adapter 2 and the tab 1-2 and reduce the risk of the tab 1-2 tearing caused by the expansion of the electrode assembly 1.

[0049] In some embodiments, the adapter piece 2 is provided with a sealant layer 4, which is located between the body part 2-1 and the connecting part 2-2.

[0050] like Figure 3 As shown, the adapter plate 2 is provided with a sealing layer 4, which is made of materials such as polypropylene. The sealing layer 4 is located between the main body 2-1 and the connecting part 2-2, so that when the battery cell is subsequently heat-sealed with aluminum-plastic film, it can provide a heat-sealing mating position for the adapter plate 2, ensuring the sealing effect of the battery cell.

[0051] In some embodiments, the sealant layer 4 is located on the side of the tape 3 away from the connector 2-2, and the orthographic projection of the tape 3 on the adapter piece 2 at least partially covers the orthographic projection of the sealant layer 4 on the adapter piece 2.

[0052] like Figure 2 As shown, the sealant layer 4 is located on the side of the tape 3 away from the connecting part 2-2. This allows the sealant layer 4 to be applied after the tape 3 is attached to the adapter piece 2. The orthographic projection of the tape 3 on the adapter piece 2 at least partially covers the orthographic projection of the sealant layer 4 on the adapter piece 2, which can improve structural stability.

[0053] In some embodiments, the sealant layer 4 is disposed in the same layer as the tape 3, and the edge of the sealant layer 4 abuts against or is spaced from the edge of the tape 3.

[0054] like Figure 3 As shown, the sealant layer 4 and the tape 3 can be set in the same layer to improve space utilization. The edge of the sealant layer 4 and the edge of the tape 3 can be set to abut or spaced apart to ensure sealing effect.

[0055] The battery cell can be manufactured by first winding or stacking positive and negative electrode sheets and separators to form electrode assembly 1; then hot pressing the main body 1-1 of electrode assembly 1, and shaping the tabs 1-2 of electrode assembly 1 by ultrasonic pre-welding and cutting; then clamping the tabs 1-2 between the two connecting parts 2-2 of the adapter piece 2 and ultrasonically welding them to form three solder areas; finally, covering the solder areas with tape 3, and attaching the edges of the tape 3 to the main body 1-1 to complete the manufacturing process.

[0056] In some embodiments of this application, a secondary battery is provided, including the battery cell as described in any of the above embodiments.

[0057] Secondary batteries consist of one or more cells and can be used in electrical devices, such as vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0058] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0059] Furthermore, given that details have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0060] Although this application has been described in conjunction with embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0061] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: An electrode assembly, including a body and tabs extending from the body; The adapter includes a connecting body and two connecting parts, the two connecting parts being located at one end of the body and stacked, the width of the connecting parts being greater than the width of the tab; the tab is welded between the two connecting parts and forms a first solder mark area on the tab; the two connecting parts are welded together to form two second solder mark areas, the two second solder mark areas being located on both sides of the tab along its width direction.

2. The battery cell according to claim 1, characterized in that, The first solder area is a strip-shaped structure extending along the width direction of the electrode assembly, and the second solder area is a strip-shaped structure extending along the length direction of the electrode assembly.

3. The battery cell according to claim 1, characterized in that, The distance between the first solder area and the edge of the tab is greater than or equal to 2 mm, and the distance between the second solder area and the tab is greater than or equal to 4 mm and less than or equal to 10 mm.

4. The battery cell according to claim 1, characterized in that, The thicknesses of the two connecting parts are not equal.

5. The battery cell according to claim 1, characterized in that, The adapter piece is attached with two layers of adhesive tape, the width of which is greater than the width of the connecting part. The connecting part is located between the two adhesive tapes, and the adhesive tapes cover the first soldering area and the second soldering area.

6. The battery cell according to claim 5, characterized in that, One side of the tape is attached to the top of the body.

7. The battery cell according to claim 5, characterized in that, The adapter plate is provided with a sealant layer, which is located between the main body and the connecting part.

8. The battery cell according to claim 7, characterized in that, The sealant layer is located on the side of the tape away from the connector, and the orthographic projection of the tape on the adapter piece at least partially covers the orthographic projection of the sealant layer on the adapter piece.

9. The battery cell according to claim 7, characterized in that, The sealant layer is disposed in the same layer as the tape, and the edge of the sealant layer abuts against or is spaced apart from the edge of the tape.

10. A secondary battery, characterized in that, Includes the battery cell described in any one of claims 1-9.

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