Battery cell and battery

Abstract

The utility model provides a battery cell and battery, the battery cell comprises a positive plate, a negative plate and a diaphragm arranged between the positive plate and the negative plate, the positive plate, the negative plate and the diaphragm are superposed in sequence, the positive plate comprises a first current collector and first active coatings, the first active coatings are arranged on the surfaces of the two sides of the first current collector in the thickness direction, and the second active coatings are arranged on the surfaces of the two sides of the first current collector in the thickness direction. The first active coatings on the two sides are symmetrically arranged, the negative plate comprises a second current collector and second active coatings, the second active coatings are arranged on the surfaces of the two sides of the second current collector in the thickness direction, and the second active coatings on the two sides form a dislocation area along at least one end of the length direction of the second current collector. According to the battery cell, no height difference exists in the thickness direction of the positive plate, so that the positive plate does not have a dislocation area influenced by shearing force in the circulating process, the welding strength of the positive plate is improved, and the problem that the pole piece structure of a battery in the prior art has a piece breaking risk is solved; and the performance and the safety of the battery are influenced.

Description

Technical Field

[0001] This application relates to the field of battery-related technology, and more specifically, to a battery cell and a battery. Background Technology

[0002] In existing technologies, cylindrical pouch lithium-ion batteries are widely used in e-cigarettes, smart headphones, styluses, and smart home consumer products due to their high maturity, consistency, energy density, low cost, and high production efficiency. The electrode structure designs of these batteries mainly include top-out tab structures, center-mounted tab structures, and all-tab structures. Among these, the top-out tab structure has become the mainstream choice in current consumer products due to its simple structure and mature equipment technology.

[0003] However, cylindrical pouch lithium-ion batteries with a tab-shaped head have significant defects during cycling. Especially in the application of large-diameter cylindrical batteries, the breakage problem mainly occurs in the misaligned area at the tail of the positive electrode. This problem is not only difficult to solve effectively by conventional methods such as improving tab burrs, reducing winding tension, or increasing foil tensile strength, but also poses a potential risk to the safety and performance of the battery because the broken cells cannot be screened.

[0004] In existing technologies, the active coating at the tail of the positive electrode forms a misaligned region, creating a height difference along the thickness direction. This height difference, during battery charge-discharge cycles, is accompanied by the periodic expansion and contraction of the electrode, causing the misaligned region to bear significant shear forces. Positive electrodes, often made of aluminum foil, are more prone to breakage under stress compared to negative electrode materials. Furthermore, in existing technologies, after the positive electrode is wound, the misaligned region is located on the outer ring of the cell, experiencing even greater forces and becoming a weak point in the battery structure, thus leading to electrode breakage.

[0005] As can be seen from the above, the electrode structure of batteries in the existing technology has the risk of electrode breakage, which affects the performance and safety of the battery. Utility Model Content

[0006] The main objective of this invention is to provide a battery cell and battery to solve the problem that the electrode structure of batteries in the prior art has the risk of electrode breakage, which affects the performance and safety of the battery.

[0007] To achieve the above objectives, according to one aspect of the present invention, a battery cell is provided. The battery cell includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The positive electrode, the negative electrode, and the separator are stacked sequentially. The positive electrode includes a first current collector and a first active coating. The first active coating is disposed on the surfaces of both sides of the first current collector in the thickness direction, and the first active coatings on both sides are symmetrically disposed. The negative electrode includes a second current collector and a second active coating. The second active coating is disposed on the surfaces of both sides of the second current collector in the thickness direction, and the second active coatings on both sides form a misaligned region at at least one end along the length direction of the second current collector.

[0008] Furthermore, the positive electrode also includes a positive tab, and along the length direction of the first current collector, the first end of the first current collector has a first empty foil region, the positive tab is connected to the first current collector in the first empty foil region, and the positive tab is connected to the surface of the first current collector facing the negative electrode.

[0009] Furthermore, the positive electrode also includes a first adhesive paper, which is provided on both sides of the first current collector along the thickness direction of the first current collector. The first adhesive paper has a first portion adhered to the first active coating and a second portion adhered to the first empty foil area.

[0010] Furthermore, the first adhesive tape is attached to the positive electrode tab.

[0011] Furthermore, the tail end of the first current collector has a second empty foil region, and the positive electrode also includes a first adhesive paper. Along the thickness direction of the first current collector, the first adhesive paper is provided on both sides of the tail end of the first current collector. The first adhesive paper has a first part adhered to the first active coating and a second part adhered to the second empty foil region.

[0012] Furthermore, along the length direction of the second current collector, the second current collector has a head end and a tail end. The head end of the second current collector has a third empty foil region on the side facing the positive electrode plate, and the head end of the second current collector has a fourth empty foil region on the side away from the positive electrode plate. Along the length direction of the second current collector, the extension length of the third empty foil region is greater than the extension length of the fourth empty foil region, forming a misaligned region. The negative electrode plate also includes a negative electrode tab, which is connected to the second current collector at the third empty foil region and connected to the surface of the second current collector facing the positive electrode plate.

[0013] Furthermore, the ends of the second active coatings on both sides are flush with the tail end of the second current collector.

[0014] Furthermore, the first current collector has a first empty foil region at its head end, and the extension length of the third empty foil region is greater than the extension length of the first empty foil region along the length direction of the first current collector.

[0015] Furthermore, the negative electrode also includes a third adhesive paper and a fourth adhesive paper. The third adhesive paper is disposed in the third empty foil area, a portion of the third adhesive paper is bonded to the negative electrode tab, and another portion of the third adhesive paper is bonded to the second current collector. The fourth adhesive paper is disposed on the side of the second current collector away from the positive electrode, a portion of the fourth adhesive paper is bonded to the second active coating, and another portion of the fourth adhesive paper is bonded to the second current collector in the fourth empty foil area.

[0016] In another aspect, this utility model provides a battery comprising the aforementioned battery cell.

[0017] By applying the technical solution of this utility model, the battery cell of this application adopts a first active coating that is symmetrically arranged on both sides of the thickness direction of the first current collector of the positive electrode sheet, ensuring that there is no height difference in the thickness direction of the positive electrode sheet, so that there is no misalignment area affected by shear force during the cycle, thereby improving the welding strength of the positive electrode sheet, significantly improving the problem of battery breakage during cycle, and improving the production quality of the battery. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0019] Figure 1 A schematic diagram of the positive electrode sheet of this utility model is shown;

[0020] Figure 2 A schematic diagram of the negative electrode sheet of this utility model is shown.

[0021] The above figures include the following reference numerals:

[0022] 10. Positive electrode sheet; 110. First current collector; 111. First empty foil region; 112. Second empty foil region; 120. First active coating; 130. Positive electrode tab; 140. First adhesive tape; 150. Second adhesive tape; 20. Negative electrode sheet; 210. Second current collector; 211. Third empty foil region; 212. Fourth empty foil region; 220. Second active coating; 230. Negative electrode tab; 240. Third adhesive tape; 250. Fourth adhesive tape. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0025] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0026] To address the risk of electrode breakage in existing battery technologies, which affects battery performance and safety, this application provides a battery comprising a casing and a cell disposed inside the casing. By rationally configuring the structure of the active coating on the current collector of the cell, the battery ensures the stability of the cell structure and improves the production quality of the battery.

[0027] The battery is a cylindrical soft-pack lithium battery.

[0028] like Figure 1 As shown, the battery cell includes a positive electrode 10, a negative electrode 20, and a separator disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the separator are stacked in sequence, and then the positive electrode 10, the negative electrode 20, and the separator are wound to form the battery cell.

[0029] The positive electrode 10 includes a first current collector 110 and a first active coating 120. The first active coating 120 is disposed on the surfaces of both sides of the first current collector 110 in the thickness direction, and the first active coatings 120 on both sides are symmetrically disposed.

[0030] Specifically, the battery cell of this application uses a first active coating 120 symmetrically formed on the surfaces of the first current collector 110 on both sides of the thickness direction of the positive electrode 10 to ensure that there is no height difference in the thickness direction of the positive electrode 10, so that there is no misalignment area affected by shear force during the cycle of the positive electrode 10, thereby improving the welding strength of the positive electrode 10, significantly improving the problem of battery breakage during cycle, and improving the production quality of the battery.

[0031] The first active coating 120 on both sides is flush with the ends of the first current collector 110 along its length direction; along the length direction of the first current collector 110, the two ends of the first active coating 120 are spaced apart from the beginning and end of the first current collector 110 to form corresponding first empty foil area 111 and second empty foil area 112. The first empty foil area 111 is symmetrically arranged on one side of the beginning of the first current collector 110 along its thickness direction, and the second empty foil area 112 is symmetrically arranged on one side of the end of the first current collector 110.

[0032] In this embodiment, the first current collector 110 is an aluminum foil structure.

[0033] like Figure 1 As shown, the positive electrode 10 also includes a positive electrode tab 130 disposed on the first current collector 110. The positive electrode tab 130 is connected to the first current collector 110 at the first empty foil region 111, that is, a positive electrode tab 130 is disposed at the beginning of the first current collector 110.

[0034] The positive electrode tab 130 is disposed on the surface of the first current collector 110 facing the negative electrode 20.

[0035] Specifically, the connection structure between the positive electrode tab 130 and the first current collector 110 can be either adhesive bonding or welding.

[0036] In this embodiment, one end of the positive electrode 130 is connected to the first end of the first current collector 110 to form a first end electrode structure, and the other end of the positive electrode 130 is used to realize power transmission.

[0037] like Figure 1 As shown, the positive electrode 10 also includes a first adhesive tape 140. The first adhesive tape 140 is provided on both sides of the first current collector 110 along the thickness direction of the first current collector 110. The first adhesive tape 140 has a first part that is adhered to the first active coating 120 and a second part that is adhered to the first empty foil area 111.

[0038] Specifically, the first adhesive tape 140 is bonded between the first current collector 110 and the first active coating 120 at the first empty foil area 111, which helps to improve the stability of the connection between the first current collector 110 and the first active coating 120, and also has an insulating function to avoid direct contact between the positive electrode 10 and the negative electrode 20, which could lead to a short circuit.

[0039] The two first adhesive sheets 140 located on both sides of the thickness direction of the first current collector 110 are symmetrically arranged relative to the first current collector 110 to ensure that the first active coating 120 on both sides of the first current collector 110 has the same adhesive force with the first current collector 110, thereby ensuring the uniformity of the force on the first end of the positive electrode 10.

[0040] In this embodiment, along the thickness direction of the first current collector 110, the first adhesive tape 140 is adhered to the positive electrode tab 130. The first adhesive tape 140 is applied to the connection area between the positive electrode tab 130 and the first current collector 110 to protect, seal and reinforce the connection area between the positive electrode tab 130 and the first current collector 110, thereby improving the stability of the structure.

[0041] In this embodiment, the tail end of the first current collector 110 has a second empty foil region 112 symmetrically arranged on both sides of the thickness direction of the first current collector 110. The positive electrode 10 also includes a second adhesive tape 150. Along the thickness direction of the first current collector 110, the tail end of the first current collector 110 is provided with a second adhesive tape 150. The second adhesive tape 150 has a first part adhered to the first active coating 120 and a second part adhered to the second empty foil region 112.

[0042] Specifically, the second adhesive tape 150 is bonded between the first current collector 110 and the first active coating 120 at the second empty foil area 112, which helps to improve the stability of the connection between the first current collector 110 and the first active coating 120, and also has an insulating function to avoid direct contact between the positive electrode 10 and the negative electrode 20, which could lead to a short circuit.

[0043] Furthermore, the two second adhesive strips 150 located on both sides of the first current collector 110 in the thickness direction are symmetrically arranged relative to the first current collector 110 to ensure that the adhesion force between the first active coating 120 on both sides of the first current collector 110 and the first current collector 110 is the same, thereby ensuring the uniformity of the force on the beginning end of the positive electrode sheet 10. At the same time, the second adhesive strip 150 at the end of the first current collector 110 has an insulating effect, preventing short circuits caused by contact between the end of the first current collector 110 and the end of the second current collector 210 during the winding and forming process of the battery cell.

[0044] like Figure 2 As shown, the negative electrode 20 includes a second current collector 210 and a second active coating 220. The second active coating 220 is disposed on the surfaces of both sides of the second current collector 210 in the thickness direction, and the second active coatings 220 on both sides form a misaligned region at at least one end along the length direction of the second current collector 210.

[0045] In this application, a misaligned region is formed between the second active coatings 220 on both sides of the second current collector 210 in the thickness direction of the negative electrode 20, so as to ensure that the first current collector 110 and the second current collector 210 form a completely insulating structure during the stacking of the positive electrode 10 and the negative electrode 20.

[0046] Specifically, along the length of the second current collector 210, the second current collector 210 has a beginning end and a end end. The beginning end of the second current collector 210 has a third empty foil region 211 on the side facing the positive electrode 10, and a fourth empty foil region 212 on the side facing away from the positive electrode 10. Along the length of the second current collector 210, the extension length of the third empty foil region 211 is greater than the extension length of the fourth empty foil region 212, forming a misaligned region.

[0047] It is understood that the third empty foil region 211 and the fourth empty foil region 212 are formed between the two ends of the second active coating 220 and the first and last ends of the second current collector 210. The extension length of the third empty foil region 211 is greater than that of the extension length of the second active coating 220 on the corresponding side. As a result, a misalignment is formed between the ends of the second active coating 220 on both sides of the first end of the second current collector 210. The non-overlapping parts of the third empty foil region 211 and the fourth empty foil region 212 form a misalignment area.

[0048] In this embodiment, along the length direction of the first current collector 110, the extension length of the third empty foil region 211 is greater than the extension length of the first empty foil region 111.

[0049] In this embodiment, the second current collector 210 is a copper foil structure. Compared to an aluminum foil structure, the copper foil structure has better strength and structural stability. The structural strength of the second current collector 210 is superior to that of the first current collector 110, and the second current collector 210 is less prone to breakage. Therefore, it can be understood that this application employs a structure that forms a height difference along the thickness direction of the second current collector 210, which helps to strengthen the overall strength of the battery cell and avoids the occurrence of electrode breakage.

[0050] This application employs a structure in which the first current collector 110 is fully coated with a first active coating 120 on both sides in the thickness direction, and the second current collector 210 is coated with a staggered second active coating 220 on both sides in the thickness direction. This structure eliminates shear forces during cycling, improving the cycle stability and safety of the battery. During battery cycling, the structure of the positive electrode 10 is more stable and less prone to breakage, thereby extending the battery's lifespan.

[0051] In this embodiment, the second active coatings 220 on both sides form a misaligned region at the beginning of the second current collector 210, and the ends of the second active coatings 220 on both sides are flush with the end of the second current collector 210. During the winding of the battery cell, the area at the end of the second current collector 210 that is in contact with the first current collector 110 is provided with the second active coating 220, thereby ensuring insulation between the second current collector 210 and the first current collector 110.

[0052] like Figure 2 As shown, the negative electrode 20 also includes a negative electrode tab 230, which is connected to a second current collector 210 at the third empty foil region 211, and the negative electrode tab 230 and the second current collector 210 are connected to the surface of the positive electrode 10.

[0053] Specifically, the connection structure between the negative electrode tab 230 and the second current collector 210 can be either adhesive bonding or welding.

[0054] In this embodiment, one end of the negative electrode 230 is connected to the first end of the second current collector 210 to form a first end electrode structure, and the other end of the negative electrode 230 is used to realize power transmission.

[0055] like Figure 2 As shown, the negative electrode 20 also includes a third adhesive tape 240, which is disposed in the third empty foil area 211. A portion of the third adhesive tape 240 is bonded to the negative electrode tab 230, and another portion of the third adhesive tape 240 is bonded to the second current collector 210.

[0056] Specifically, the third adhesive tape 240 is applied to the connection area between the negative electrode tab 230 and the second current collector 210. The third adhesive tape 240 can be used for insulation between the first current collector 110 and the second current collector 210. At the same time, the third adhesive tape 240 helps to strengthen the connection strength between the negative electrode tab 230 and the second current collector 210.

[0057] In an embodiment, the negative electrode 20 further includes a fourth adhesive tape 250, which is disposed on the side of the second current collector 210 away from the positive electrode 10. A portion of the fourth adhesive tape 250 is bonded to the second active coating 220, and another portion of the fourth adhesive tape 250 is bonded to the second current collector 210 at the fourth empty foil area 212.

[0058] Specifically, the fourth adhesive tape 250 is bonded between the second current collector 210 and the second active coating 220 at the fourth empty foil area 212, which helps to improve the stability of the connection between the second current collector 210 and the second active coating 220, and also has an insulating function to avoid direct contact between the positive electrode 10 and the negative electrode 20, which could lead to a short circuit.

[0059] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0060] The battery cell of this application uses a first active coating 120 that is symmetrically arranged on the surfaces of the first current collector 110 on both sides of the thickness direction of the positive electrode 10. This ensures that there is no height difference in the thickness direction of the positive electrode 10, so that there is no misalignment area affected by shear force during the cycle of the positive electrode 10. This improves the welding strength of the positive electrode 10, significantly improves the problem of battery breakage during cycle, and improves the production quality of the battery.

[0061] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0062] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0063] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0064] 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. An electric cell, characterized by, include: A positive electrode (10), a negative electrode (20), and a separator disposed between the positive electrode (10) and the negative electrode (20) are stacked sequentially. The positive electrode (10) includes a first current collector (110) and a first active coating (120). The first active coating (120) is disposed on the surfaces of the first current collector (110) on both sides in the thickness direction, and the first active coating (120) on both sides is symmetrically disposed. The negative electrode (20) includes a second current collector (210) and a second active coating (220). The second active coating (220) is disposed on the surfaces of both sides of the second current collector (210) in the thickness direction, and the second active coating (220) on both sides forms a misaligned region at at least one end along the length direction of the second current collector (210).

2. The electric cell of claim 1, wherein, The positive electrode (10) further includes a positive electrode tab (130). Along the length direction of the first current collector (110), the first end of the first current collector (110) has a first empty foil area (111). The positive electrode tab (130) is connected to the first current collector (110) at the first empty foil area (111). The positive electrode tab (130) is connected to the surface of the first current collector (110) facing the negative electrode (20).

3. The electric cell of claim 2, wherein, The positive electrode (10) further includes a first adhesive tape (140), which is provided on both sides of the first current collector (110) along the thickness direction of the first current collector (110). The first adhesive tape (140) has a first part adhered to the first active coating (120) and a second part adhered to the first empty foil area (111).

4. The electric cell of claim 3, wherein, The first adhesive tape (140) is attached to the positive electrode tab (130).

5. The electric cell of any one of claims 1 to 4, wherein, The first current collector (110) has a second empty foil area (112) at its tail end. The positive electrode (10) also includes a second adhesive tape (150). Along the thickness direction of the first current collector (110), the second adhesive tape (150) is provided on both sides of the tail end of the first current collector (110). The second adhesive tape (150) has a first part adhered to the first active coating (120) and a second part adhered to the second empty foil area (112).

6. The electric cell of any one of claims 1 to 4, wherein, Along the length direction of the second current collector (210), the second current collector (210) has a head end and a tail end. The head end of the second current collector (210) has a third empty foil region (211) on the side facing the positive electrode plate (10), and a fourth empty foil region (212) on the side away from the positive electrode plate (10). Along the length direction of the second current collector (210), the extension length of the third empty foil region (211) is greater than the extension length of the fourth empty foil region (212), forming the misalignment region. The negative electrode plate (20) also includes a negative electrode tab (230). The negative electrode tab (230) is connected to the second current collector (210) at the third empty foil region (211), and the negative electrode tab (230) is connected to the surface of the second current collector (210) facing the positive electrode plate (10).

7. The electric cell of claim 6, wherein, The ends of the second active coating (220) on both sides are flush with the tail end of the second current collector (210).

8. The electric cell of claim 6, wherein, The first current collector (110) has a first empty foil area (111) at its first end. Along the length direction of the first current collector (110), the extension length of the third empty foil area (211) is greater than the extension length of the first empty foil area (111).

9. The electric cell of claim 6, wherein, The negative electrode (20) also includes: A third adhesive tape (240) is disposed in the third empty foil area (211). A portion of the third adhesive tape (240) is bonded to the negative electrode tab (230), and another portion of the third adhesive tape (240) is bonded to the second current collector (210). A fourth adhesive tape (250) is disposed on the side of the second current collector (210) away from the positive electrode (10). A portion of the fourth adhesive tape (250) is bonded to the second active coating (220), and another portion of the fourth adhesive tape (250) is bonded to the second current collector (210) at the fourth empty foil area (212).

10. A battery, characterized by The battery comprises the cell according to any one of claims 1 to 9.

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