A battery cell and a battery

Abstract

This utility model relates to the field of battery technology, and discloses a battery cell and a battery. The battery cell includes: an electrode assembly formed by sequentially stacking and winding a first insulating layer, a second electrode, and a first electrode along a winding direction; the electrode assembly has a first bending region; the electrode assembly has multiple winding layers formed from the inside out, the innermost layer of which is the first winding layer; the first electrode in the first winding layer has a first empty foil region and a first coating region spaced apart; the first coating region has a first active material layer; the first empty foil region is located in the first bending region; and a first barrier layer is disposed in the first bending region, on the surface of the first electrode near the first insulating layer, and covers the first empty foil region. This utility model's battery cell and battery solve the problem of lithium deposition in the first bending region of the first electrode after long-term use by setting a first empty foil region in the first bending region of the first electrode and covering the first empty foil region with a first barrier layer.

Description

Technical Field

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

[0002] A battery composed of cells assembled by a winding method is called a wound battery. Wound batteries include cylindrical wound batteries and prismatic wound batteries. For prismatic wound batteries, the inner electrodes have larger bending angles on both sides and need to withstand greater curvature. This causes the electrode coating to be subjected to both compressive and shear stresses, weakening the bonding force between active material particles and even causing microcracks. Bending leads to localized compression of the separator, uneven electrolyte wetting, and obstruction of the lithium-ion diffusion path, forming localized high current density areas. Coating cracking increases the contact resistance between the current collector and the active material, and the local polarization voltage exceeds the lithium deposition potential. Cyclic stress causes cracks to propagate, exposing new active surfaces. After repeated charge and discharge cycles, lithium can easily precipitate from the active material on the electrode surface in the bent areas, posing a safety risk and causing battery performance degradation. Utility Model Content

[0003] The purpose of this invention is to provide a battery cell and a battery that solves the problem of lithium deposition in the first bending zone after long-term use of the first electrode.

[0004] To achieve the above objectives, in a first aspect, this utility model provides a battery cell, comprising:

[0005] An electrode assembly has a winding direction. The electrode assembly includes a first electrode, a second electrode, a first insulating layer, and a second insulating layer. The first insulating layer, the second electrode, the second insulating layer, and the first electrode are sequentially stacked and wound along the winding direction to form the electrode assembly. The electrode assembly has a first bending region.

[0006] The electrode assembly has multiple winding layers formed from the inside out. The innermost layer of the multiple winding layers is the first winding layer. The first electrode in the first winding layer has a first empty foil area and a first coating area that are spaced apart. The first coating area is provided with a first active material layer. The first empty foil area is located in the first bending area.

[0007] A first barrier layer is disposed in the first bending area, on the side surface of the first electrode sheet near the first insulating layer, and covers the first empty foil area.

[0008] In some embodiments, the electrode assembly has a first direction, the electrode assembly has a second bending region disposed opposite to the first bending region along the first direction, the first electrode sheet in the first winding layer has a second empty foil region and a second coating region disposed at intervals, the second coating region is provided with a second active material layer, and the second empty foil region is located in the second bending region.

[0009] In some embodiments, the first barrier layer is an adhesive layer, and the porosity of the first barrier layer is less than that of the first isolation layer and the second isolation layer.

[0010] In some embodiments, the battery cell further includes a second barrier layer disposed in the second empty foil region and on the inner surface of the first electrode.

[0011] In some embodiments, the second barrier layer is an adhesive layer, and the porosity of the second barrier layer is less than that of the first isolation layer and the second isolation layer.

[0012] In some embodiments, the first electrode has a second heat-affected zone along the winding direction, the second heat-affected zone being located on both sides of the second empty foil zone, and the second heat-affected zone having a second deactivating material layer.

[0013] In some embodiments, the first electrode has a first heat-affected zone along the winding direction, the first heat-affected zone being located on both sides of the first empty foil zone, and the first heat-affected zone having a first deactivating material layer.

[0014] In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0015] In some embodiments, the battery cell further includes a first tab and a second tab, wherein the first tab is electrically connected to a first electrode plate and the second tab is electrically connected to a second electrode plate.

[0016] In a second aspect, this utility model provides a battery, including the battery cell provided in the first aspect.

[0017] The present invention discloses an electrode assembly and a battery, which, compared with the prior art, have the following advantages:

[0018] The electrode assembly has a winding direction and includes a first electrode, a second electrode, a first insulating layer, and a second insulating layer. The first insulating layer, the second electrode, the second insulating layer, and the first electrode are sequentially stacked and wound along the winding direction to form the electrode assembly. The electrode assembly has a first bending region. The electrode assembly has multiple winding layers formed from the inside out. The innermost layer of the multiple winding layers is the first winding layer. The first electrode in the first winding layer has a first empty foil region and a first coating region spaced apart. The first coating region is provided with a first active material layer. The first empty foil region is located in the first bending region. A first barrier layer is disposed in the first bending region, on the surface of the first electrode near the first insulating layer, and covers the first empty foil region. Thus, by setting a first empty foil area in the first bending area of ​​the first electrode, the first electrode does not have a first active material layer in the first bending area, and a first barrier layer is covered in the first empty foil area. The first isolation layer in the first bending area is the innermost layer, which avoids the first corner from being too loose, resulting in an excessive gap between the first electrode and the second electrode, and solves the problem of lithium plating on the first electrode in the first ring after the electrode assembly is charged and discharged. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view of a battery cell along a first direction according to some embodiments of the present invention.

[0020] Figure 2 yes Figure 1 A magnified schematic diagram of the first bend in the middle section.

[0021] Figure 3 This is a schematic diagram of the unfolded structure of the first electrode of a battery cell according to some embodiments of this utility model.

[0022] In the figure: 1. Electrode assembly; 1a. First bending area; 1b. Second bending area; 11. Second electrode; 12. First electrode; 12a. First empty foil area; 12b. First coating area; 12c. Second empty foil area; 12d. Second coating area; 12e. First heat-affected zone; 12f. Second heat-affected zone; 121. First active material layer; 122. Second active material layer; 13. First isolation layer; 14. Second isolation layer; 2. First barrier layer; 3. Second barrier layer; 4. Second electrode tab; 5. First electrode tab; X. First direction; A. Winding direction. Detailed Implementation

[0023] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0024] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the embodiments of the application, "parallel" refers to a state in which the angle formed by two lines, a line and a surface, or a surface is -1° to 1°. "Perpendicular" refers to a state in which the angle formed by two lines, a line and a surface, or a surface is 89° to 91°. Equal distances, equal angles, or equal areas refer to a state in which the tolerance range is -1% to 1%.

[0028] like Figures 1-3As shown, some embodiments of the present invention provide a battery cell including: an electrode assembly 1 and a first barrier layer 2. The electrode assembly 1 has a winding direction A, and the electrode assembly 1 includes a first electrode 12, a second electrode 11, a first insulating layer 13 and a second insulating layer 14. The first insulating layer 13, the second electrode 11, the second insulating layer 14 and the first electrode 12 are sequentially stacked and wound along the winding direction A to form the electrode assembly 1. The electrode assembly 1 has a first bending region 1a.

[0029] The electrode assembly 1 has a multi-layer winding layer formed from the inside out. The innermost layer of the multi-layer winding layer is the first winding layer. The first electrode 12 in the first winding layer has a first empty foil area 12a and a first coating area 12b arranged at intervals. The first coating area 12b is provided with a first active material layer 121. The first empty foil area 12a is located in the first bending area 1a.

[0030] The first barrier layer 2 is disposed in the first bending area 1a and on the side surface of the first electrode 12 near the first insulating layer 13, and covers the first empty foil area 12a.

[0031] Thus, by setting a first empty foil area 12a in the first bending area 1a of the first electrode 12, the first electrode 12 does not have a first active material layer 121 in the first bending area 1a, and a first barrier layer 2 is set in the first empty foil area 12a. The first isolation layer 13 in the first bending area 1a is the innermost layer, which avoids the corners of the first winding layer from becoming loose, resulting in an excessive gap between the first electrode 12 and the second electrode 11, and solves the problem of lithium plating on the first electrode 12 in the first winding after the electrode assembly 1 is charged and discharged.

[0032] The first insulating layer 13 is provided to prevent the first electrode 12 from directly contacting the winding needle and shedding powder or foreign matter into the battery cell during the manufacturing process. Furthermore, the innermost first insulating layer 13 can be bonded during the hot-pressing process, ensuring that the inner ring of the entire electrode assembly remains open.

[0033] In conventional designs, the innermost (first) winding of the electrode assembly has the greatest bending curvature and the most significant stress concentration. If the electrode in this area is coated with an active material layer, under repeated charging and discharging and mechanical stress, the interface between the active material layer and the electrode is prone to microcracks, peeling, or loosening. This results in an excessively large physical gap between the electrode in this area and the separator layer immediately adjacent to it. During charging, if such an excessively large physical gap exists in the first winding bending area, the actual electrode surface area participating in the reaction in this area will decrease or poor contact will occur, potentially leading to an abnormally high local current density. Lithium ions may encounter obstacles or delays on their migration path to the active material surface of the electrode. This can cause some lithium ions to fail to embed into the electrode in a timely and uniform manner, instead gaining electrons directly on the electrode surface and being reduced and deposited, forming metallic lithium (i.e., lithium plating). Lithium plating not only reduces capacity but also grows lithium dendrites, which can pierce the separator and cause short circuits, posing a serious safety hazard.

[0034] Based on the structural configuration of the first electrode 12 in this embodiment, a first barrier layer 2 is provided on the inner surface of the first empty foil region 12a to enhance structural stability and interface contact. After the first barrier layer 2 is cured, it can significantly enhance the rigidity and deformation resistance of the first electrode 12 in the first empty foil region 12a, preventing the first electrode 12 from springing back or wrinkling after bending, providing mechanical support, and ensuring that the first electrode 12 in the first empty foil region 12a and the first isolation layer 13 adjacent to its outer side can maintain a tight and uniform physical contact, effectively eliminating or minimizing the gap between the two and improving interface adhesion. Although the first electrode 12 does not have active material in the first empty foil region 12a, the material selection of the first barrier layer 2 ensures the wetting of the electrolyte and the necessary conduction of lithium ions (as an ion channel), without affecting the overall ion pathway.

[0035] like Figure 3 As shown, in some embodiments, the electrode assembly 1 has a first direction X, and the electrode assembly has a second bending region 1b disposed opposite to the first bending region 1a along the first direction X. The first electrode 12 in the first winding layer has a second empty foil region 12c and a second coating region 12d disposed at intervals. The second coating region 12d is provided with a second active material layer 122, and the second empty foil region 12c is located in the second bending region 1b. In this way, by setting the second empty foil region 12c, the first electrode 12 does not have the second active material layer 122 in the second bending region 1b, which can avoid the corners of the first winding layer from becoming loose, resulting in an excessively large gap between the first electrode 12 and the second electrode 11, and solve the problem of lithium plating on the first electrode 12 in the first winding after the electrode assembly 1 has been charged and discharged.

[0036] like Figure 1As shown, in some embodiments, the second barrier layer 3 is an adhesive layer, and the porosity of the second barrier layer 3 is lower than that of the first isolation layer 13 and the second isolation layer 14. Thus, because the second barrier layer 3 is elastic, it provides a buffering effect, reducing the localized excessive stress on the first electrode 12 in the second bending region 1b due to excessive bending angle, thereby reducing the risk of breakage of the first electrode 12 due to excessive localized stress. Furthermore, the porosity of the second barrier layer 3 forms a functionally graded structure with the porosity of the first isolation layer 13 and the second isolation layer 14, with the high porosity of the first isolation layer 13 and the second isolation layer 14 maintaining electrolyte wetting and lithium-ion migration channels.

[0037] like Figure 1 and 3 As shown, in some embodiments, the battery cell further includes a second barrier layer 3, disposed in the second empty foil region 12c and on the inner surface of the first electrode 12. Thus, the second barrier layer 3 can protect the second empty foil region 12c of the first electrode 12.

[0038] Based on the structural configuration of the first electrode 12 in this embodiment, a second barrier layer 3 is provided on the inner surface of the second empty foil region 12c to enhance structural stability and interface contact. After the second barrier layer 3 is cured, it can significantly enhance the rigidity and deformation resistance of the first electrode 12 in the second empty foil region 12c, preventing the first electrode 12 from springing back or wrinkling after bending, providing mechanical support, and ensuring that the first electrode 12 in the second empty foil region 12c and the first isolation layer 13 adjacent to its outer side can maintain a tight and uniform physical contact, effectively eliminating or minimizing the gap between the two and improving interface adhesion. Although the first electrode 12 does not have active material in the second empty foil region 12c, the material selection of the second barrier layer 3 ensures the wetting of the electrolyte and the necessary conduction of lithium ions (as an ion channel), without affecting the overall ion pathway.

[0039] like Figure 3As shown, in some embodiments, the first electrode 12 along the winding direction A has a second heat-affected zone 12f, which is located on both sides of the second empty foil region 12c. The second heat-affected zone 12f is provided with a second deactivating material layer 124. Specifically, in actual processing, the second empty foil region 12c also has a second active material layer 122. The second active material layer 122 of the second empty foil region 12c is cleaned by a laser cleaning process to obtain the second empty foil region 12c. The second deactivating material layer 124 is formed on both sides of the second empty foil region 12c. The second deactivating material layer 124 is formed when the high temperature generated by laser cleaning causes the second active material layer 122 to lose its activity, but it is not completely removed. The laser cleaning process solves the contamination problem of traditional dry / wet cleaning. Laser cleaning can precisely control the cleaning range. The formation of the deactivating material layer is actually a byproduct of cleaning, but it is crucial to the battery safety performance. Laser cleaning does not require direct contact with the surface of the first electrode 12, avoiding damage to the substrate caused by mechanical friction and chemical corrosion, thus protecting the integrity and precision of the first electrode 12. The laser beam has high energy density and good directionality, which can quickly heat and remove contaminants, resulting in high cleaning efficiency and precise positioning.

[0040] In some embodiments, the formation of the second heat-affected zone 12f is such that the first electrode 12 is continuously coated to form the second active material layer 122 during the initial coating stage. The entire area of ​​the first electrode 12 to be coated (including the part that will eventually become an empty foil) is first coated with active material slurry, and then the second empty foil area 12c is formed by laser cleaning process. This achieves precise positioning of the second empty foil area 12c. Compared with leaving a gap when coating the active material directly, it is easier to control the width, positional accuracy and edge quality of the second empty foil area 12c.

[0041] like Figure 3As shown, in some embodiments, the first electrode 12 along the winding direction A has a first heat-affected zone 12e, which is located on both sides of the first empty foil area 12a. The first heat-affected zone 12e is provided with a first deactivating material layer 123. Specifically, in actual processing, the first empty foil area 12a also has a first active material layer 121. The first heat-affected zone 12e of the first empty foil area 12a is cleaned by laser cleaning process to obtain the first empty foil area 12a, and the first deactivating material layer 123 is formed on both sides of the first empty foil area 12a. The first deactivating material layer 123 is formed when the high temperature generated by laser cleaning causes the first active material layer 121 to lose its activity, but it is not completely removed. The laser cleaning process solves the contamination problem of traditional dry / wet cleaning. Laser cleaning can precisely control the cleaning range and avoid secondary damage. The formation of the deactivating material layer is actually a by-product of cleaning, but it is crucial to the battery safety performance. Laser cleaning does not require direct contact with the surface of the first electrode 12, avoiding damage to the substrate caused by mechanical friction and chemical corrosion, thus protecting the integrity and precision of the first electrode 12. The laser beam has high energy density and good directionality, which can quickly heat and remove contaminants, resulting in high cleaning efficiency and precise positioning.

[0042] In some embodiments, the formation of the first heat-affected zone 12e is such that the first electrode 12 is continuously coated to form the first deactivating material layer 123 during the initial coating stage. The entire area of ​​the first electrode 12 that needs to be coated (including the part that will eventually become an empty foil) is first coated with active material slurry, and then the first empty foil area 12a is formed by laser cleaning process. This achieves precise positioning of the first empty foil area 12a. Compared with leaving a gap when coating the active material directly, it is easier to control the width, positional accuracy and edge quality of the first empty foil area 12a.

[0043] like Figure 1 As shown, in some embodiments, the first barrier layer 2 is an adhesive layer, and the porosity of the first barrier layer 2 is lower than that of the first isolation layer 13 and the second isolation layer 14. Thus, because the first barrier layer 2 is elastic, it provides a buffering effect, reducing the localized excessive stress on the first electrode 12 in the first bending region 1a due to an excessive bending angle, thereby reducing the risk of breakage of the first electrode 12 due to excessive localized stress. Furthermore, the porosity of the first barrier layer 2 forms a functionally graded structure with the porosity of the first isolation layer 13 and the second isolation layer 14, with the high porosity of the first isolation layer 13 and the second isolation layer 14 maintaining electrolyte wetting and lithium-ion migration channels.

[0044] In some embodiments, the first electrode 12 is a positive electrode and the second electrode 11 is a negative electrode. It should be noted that the positive electrode needs to address the lithium plating problem, while the negative electrode does not.

[0045] The positive electrode includes a positive current collector and a positive active material disposed on at least one surface of the positive current collector. The positive current collector has two surfaces perpendicular to its thickness direction, and the positive active material is disposed on at least one of the two opposing surfaces of the positive current collector.

[0046] In some embodiments, the positive electrode current collector includes either a metal foil or a composite current collector. When the positive electrode current collector is a metal foil, it includes at least one of the following: surface-plated aluminum, stainless steel, surface-plated stainless steel, aluminum, nickel, carbon electrode, carbon, nickel, or titanium. When the positive electrode current collector includes a composite current collector, it comprises a polymer material layer and a metal layer arranged sequentially. The polymer material layer includes, but is not limited to, substrates such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, and polyethylene; the metal layer includes, but is not limited to, metallic materials such as aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys.

[0047] In some embodiments, the negative electrode includes one of a metal foil and a negative current collector. When the negative electrode includes a metal foil, the metal foil includes, but is not limited to, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium. When the negative electrode includes a negative current collector, the negative current collector includes two surfaces perpendicular to its thickness direction, and at least one of the two surfaces is provided with a negative electrode active material.

[0048] Positive electrode active materials include, but are not limited to, lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The positive electrode active material layer allows for the extraction and insertion of lithium ions. Negative electrode active materials include, but are not limited to, carbon and silicon. The negative electrode active material allows for the extraction and insertion of lithium ions.

[0049] Both the first isolation layer 13 and the second isolation layer 14 can be made of materials such as polypropylene (PP) and polyethylene (PE).

[0050] like Figure 1 As shown, in some embodiments, the battery cell further includes a first tab 5 and a second tab 4. The first tab 5 is electrically connected to the first electrode 12, and the second tab 4 is electrically connected to the second electrode 11. Thus, the first tab 5 and the second tab 4 satisfy the current transmission requirements.

[0051] Specifically, the battery cell also includes a casing. The first tab 5 serves as the positive current outlet, connecting the first electrode 12 to the positive terminal of the casing. The second tab 4 serves as the negative current outlet, connecting the second electrode 11 to the negative terminal of the casing, thus forming a complete current path from electrode to tab to terminal to external circuit. The selection of tab materials needs to consider conductivity, density, corrosion resistance, weldability, and cost. While aluminum and copper are the mainstream materials, many variations and coating technologies are worth exploring in practical applications.

[0052] In some embodiments, the first electrode 5 is made of aluminum, aluminum-magnesium alloy, aluminum-iron alloy, or aluminum-carbon nanotube composite material. The second electrode 4 is made of copper, or has a nickel plating, graphene composite plating, or silver nanoparticle coating on its surface.

[0053] The battery provided in other embodiments of this utility model includes the battery cell provided in some embodiments.

[0054] Based on the battery structure of this embodiment, by setting a first empty foil area 12a in the first bending area 1a of the first electrode 12, the first electrode 12 does not have a first active material layer 121 in the first bending area 1a, and a first barrier layer 2 is covered in the first empty foil area 12a. The first isolation layer 13 in the first bending area 1a is the innermost layer, which avoids the first corner from being easily fluffy, resulting in an excessive gap between the first electrode 12 and the second electrode 11, and solves the problem of lithium plating on the first electrode 12 in the first ring after the electrode assembly 1 is charged and discharged.

[0055] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery cell, characterized in that, include: An electrode assembly (1) has a winding direction (A). The electrode assembly (1) includes a first electrode (12), a second electrode (11), a first insulating layer (13), and a second insulating layer (14). The first insulating layer (13), the second electrode (11), the second insulating layer (14), and the first electrode (12) are sequentially stacked and wound along the winding direction (A) to form the electrode assembly (1). The electrode assembly (1) has a first bending region (1a). The electrode assembly (1) has a multi-layer winding layer formed from the inside out. The innermost layer of the multi-layer winding layer is the first winding layer. The first electrode (12) in the first winding layer has a first empty foil area (12a) and a first coating area (12b) arranged at intervals. The first coating area (12b) is provided with a first active material layer (121). The first empty foil area (12a) is located in the first bending area (1a). A first barrier layer (2) is disposed in the first bending area (1a), on the side surface of the first electrode (12) near the first isolation layer (13), and covers the first empty foil area (12a).

2. The battery cell according to claim 1, characterized in that, The electrode assembly (1) has a first direction (X), and the electrode assembly (1) has a second bending region (1b) disposed opposite to the first bending region (1a) along the first direction (X). The first electrode sheet (12) in the first winding layer has a second empty foil region (12c) and a second coating region (12d) disposed at intervals. The second coating region (12d) is provided with a second active material layer (122). The second empty foil region (12c) is located in the second bending region (1b).

3. The battery cell according to claim 2, characterized in that, The first barrier layer (2) is an adhesive layer, and the porosity of the first barrier layer (2) is less than that of the first isolation layer (13) and the second isolation layer (14).

4. The battery cell according to claim 3, characterized in that, The battery cell also includes a second barrier layer (3), which is disposed in the second empty foil area (12c) and on the inner surface of the first electrode (12).

5. The battery cell according to claim 4, characterized in that, The second barrier layer (3) is an adhesive layer, and the porosity of the second barrier layer (3) is less than that of the first isolation layer (13) and the second isolation layer (14).

6. The battery cell according to claim 2, characterized in that, Along the winding direction (A), the first electrode (12) has a second heat-affected zone (12f), which is located on both sides of the second empty foil area (12c), and the second heat-affected zone (12f) is provided with a second deactivating material layer (124).

7. The battery cell according to claim 1, characterized in that, Along the winding direction (A), the first electrode (12) has a first heat-affected zone (12e), which is located on both sides of the first empty foil area (12a), and the first heat-affected zone (12e) is provided with a first deactivating material layer (123).

8. The battery cell according to claim 1, characterized in that, The first electrode (12) is a positive electrode, and the second electrode (11) is a negative electrode.

9. The battery cell according to any one of claims 1-8, characterized in that, The battery cell also includes a first tab (5) and a second tab (4), the first tab (5) being electrically connected to the first electrode (12), and the second tab (4) being electrically connected to the second electrode (11).

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

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