Battery cell isolating membrane structure, battery cell and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell isolating membrane structure, a battery cell and a battery. The battery cell isolating membrane structure comprises a base material layer and a conducting coating, at least one straight section and at least one bent section are arranged on the base material layer; the straight sections and the bent sections are arranged in a staggered mode. And at least part of the structure in the conduction coating is connected to the bending section. According to the utility model, the risk of lithium precipitation can be reduced; and the structural stability and the use safety performance can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and in particular relates to a battery isolation film structure, a battery core and a battery. Background Art

[0002] A lithium-ion battery is a device that converts external energy into electrical energy and stores it inside, so as to power external electrical devices (such as portable electronic devices) when needed. At present, lithium-ion batteries are widely used in electronic products such as mobile phones, tablets, and laptops. Generally, a lithium-ion wound battery cell includes a shell, an electrode assembly housed in the shell, and a pole ear connected to the electrode assembly and partially extending out of the shell. Among them, the electrode assembly includes a first pole piece, a second pole piece, and a separator. The separator is arranged between the adjacent first pole piece and the second pole piece, and is bonded and fixed to the adjacent first pole piece and the second pole piece, thereby fixing the first pole piece, the second pole piece, and the separator.

[0003] However, in most existing wound battery cells, the upper and lower surfaces of the isolation film are tightly attached to the adjacent first electrode sheet and the second electrode sheet, and at the winding corners, due to the bending corners, the spacing will be relatively large, which will lead to large Li ion transmission resistance at the corners and easily cause lithium precipitation, thereby reducing the stability and safety of use. Utility Model Content

[0004] The purpose of the utility model is to provide a battery cell isolation membrane structure to solve the problem that the transmission resistance of Li ions at the existing corners is large and lithium precipitation is easily caused.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A battery cell isolation film structure comprises a substrate layer and a conductive coating; the substrate layer is provided with at least one straight section and at least one bent section; the straight section and the bent section are mutually staggered; at least part of the structure in the conductive coating is connected to the bent section.

[0007] Preferably: the straight section is a straight position of the substrate layer in a wound state; and the bent section is a corner position of the substrate layer in a wound state.

[0008] Preferably, at least a portion of the structure in the conductive coating is connected to the straight section.

[0009] Preferably: the conductive coating covers and is connected to the bending section.

[0010] Preferably: the width of the conductive coating is equal to the width of the bending section; and / or the relationship between the length L1 of the conductive coating and the length L2 of the bending section satisfies: L1≥L2.

[0011] Preferably, the relationship between the length L1 of the conductive coating and the length L2 of the bending section satisfies: L1-L2=A; wherein A is 0.5 mm to 1.0 mm.

[0012] Preferably, the conductive coating is one of LATP material, LLZO material and LLTO material.

[0013] The utility model also discloses a battery cell, comprising a positive electrode sheet, a negative electrode sheet and a separator arranged between the negative electrode sheet and the positive electrode sheet; and the positive electrode sheet, the separator and the negative electrode sheet are wound in sequence; the separator is the battery cell separator structure described above.

[0014] The utility model also discloses a battery, comprising the battery core.

[0015] The beneficial effects of the utility model lie in that the technical solution, by adopting straight sections and bent sections that are staggered with each other and providing a conductive coating only on the bent sections, can achieve the function of the substrate layer having multiple conductive ion conduction locations during use, and can improve the conductive performance of the substrate layer in the bent sections, reduce the ion transmission resistance, and thus help reduce the risk of lithium plating; thereby improving the stability of the structure and the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following will refer to the attached Figures 1 to 4 To describe the features, advantages and technical effects of exemplary embodiments of the present utility model.

[0017] Figure 1 A cross-sectional view of a cell isolation membrane structure according to an embodiment of the present utility model;

[0018] Figure 2 A top view of a cell isolation membrane structure according to an embodiment of the utility model;

[0019] Figure 3 A top view of a cell isolation membrane structure according to an embodiment of the utility model;

[0020] Figure 4 The figure is a schematic structural diagram of a battery cell according to an embodiment of the utility model.

[0021] In the figure: 1-substrate layer; 11-bend section; 12-straight section; 2-conductive coating; 100-positive electrode sheet; 200-negative electrode sheet; 300-isolation film; 4-straight position; 5-corner position. DETAILED DESCRIPTION

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0023] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship between the cell isolation membrane structure, the cell and the battery to describe the associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and multiple situations exist alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are an "or" relationship between a cell isolation membrane structure, a cell and a battery.

[0026] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0028] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0029] The following is combined with Figure 1 to Figure 4 The utility model is further described in detail, but it is not intended to limit the utility model.

[0030] like Figure 1 and 2 As shown, in one embodiment of the utility model, the battery cell isolation membrane structure includes a substrate layer 1 and a conductive coating 2; at least one straight section 12 and at least one bent section 11 are provided on the substrate layer 1; the straight section 12 and the bent section 11 are staggered with each other; at least part of the structure in the conductive coating 2 is connected to the bent section 11.

[0031] The technical solution of the utility model adopts straight sections and bent sections that are staggered with each other and only provides a conductive coating on the bent sections, so that the substrate layer can have the function of conducting conductive ions at multiple locations during use, and can improve the conductive performance of the substrate layer in the bent sections, reduce the ion transmission resistance, and thus help reduce the risk of lithium plating; thereby improving the stability of the structure and the safety of use.

[0032] Wherein, in some embodiments, Figure 1 As shown, the conductive coating 2 is connected to the upper and lower surfaces of the substrate layer 1. That is, by coating the upper and lower surfaces of the substrate layer 1 with the Li ion conductive layer, the Li ion conductive performance on both sides of the cell isolation membrane structure can be achieved, thereby improving the flow performance of Li ions.

[0033] Specifically, in some embodiments, the conductive coating 2 is a lithium-rich material such as LATP (low-activity phosphate cross-linked polymer), LLZO (lithium lanthanum zirconium oxide), LLTO (lithium lanthanum titanium oxide), etc. The structure can further improve the conduction performance of Li ions through lithium-rich materials such as LATP, LLZO, LLTO, etc., and can effectively reduce the transmission resistance of Li ions at the bend; thereby reducing the risk of lithium precipitation; and improving the stability of the structure and the safety of use.

[0034] Specifically, in some embodiments, Figure 1 and 4As shown, the straight section 12 is the straight position 4 of the substrate layer 1 in the wound state; the bent section 11 is the corner position 5 of the substrate layer 1 in the wound state. That is, the conductive coating 2 for conducting Li ions is coated on both sides of the substrate layer 1 of the cell isolation film structure, so that Li (lithium) ions can be better conducted, and the Li ion transmission resistance at the bend can be reduced; thereby, the risk of lithium precipitation can be reduced; and the stability of the structure and the safety performance of use can be improved.

[0035] Specifically, in some embodiments (not shown), at least part of the structure of the conductive coating 2 is connected to the straight section 12. The projection of the conductive coating 2 located in the straight section 12 toward the straight section 12 is smaller than the area of ​​the straight section 12; and the projection of the conductive coating 2 located in the straight section 12 toward the straight section 12 is at most one sixth to one fifth of the area of ​​the straight section 12. In other words, the conductive coating 2 can be appropriately extended to the straight section 12, and can effectively conduct the Li (lithium) ions in the straight position 4, thereby improving the transmission performance of the Li (lithium) ions, improving the stability of the structure and the safety performance of use.

[0036] Specifically, in some embodiments, the projection of the conductive coating 2 toward the bending section 11 is less than or equal to the area of ​​the bending section 11. Figure 2 As shown, the conductive coating 2 covers and connects to the bending section 11. The structure can effectively conduct Li (lithium) ions at the bending section 11 by fully covering the conductive coating 2, thereby increasing the conduction amount of Li (lithium) ions, thereby reducing the risk of lithium precipitation; and improving the stability of the structure and the safety performance of use. Figure 3 As shown, the width of the conductive coating 2 is equal to the width of the bending section 11, and the relationship between the length L1 of the conductive coating 2 and the length L2 of the bending section 11 satisfies: L1≥L2; further, L1-L2=A, A is 0mm~1.0mm. This structure can effectively buffer the extrusion of the conductive coating 2 by the substrate layer 1 during the winding process through the conductive coating 2 of a certain size, thereby ensuring the coverage of the conductive coating 2, and can effectively ensure the overall stability of the battery cell isolation film structure, thereby improving the safety of use.

[0037] Specifically, in some embodiments, Figure 1As shown, the width of the conductive coating 2 is equal to the width of the bending section 11, the width of the conductive coating is equal to the width of the bending section, and the thickness H1 of the conductive coating 2 has a value range of: H1 = 0.1μm ~ 50μm; the thickness H2 of the substrate layer has a value range of: H2 = 1μm ~ 50μm. This structure can effectively ensure the assembly stability of the battery cell isolation film structure between the pole pieces after winding through the conductive coating 2 of a certain appropriate thickness, thereby avoiding the gap between the pole pieces from being too large to affect the insulation performance, thereby improving the safety and stability of use.

[0038] The utility model also provides a battery cell, such as Figure 4 As shown, the battery cell includes a positive electrode sheet 100, a negative electrode sheet 200 and an isolation film 300 arranged between the negative electrode sheet 200 and the positive electrode sheet 100; and the positive electrode sheet 100, the isolation film 300 and the negative electrode sheet 200 are wound in sequence to form a core structure; the isolation film 300 is the battery cell isolation film structure; the specific structure of the battery cell isolation film structure refers to the above-mentioned embodiment. Since the present battery cell adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0039] Among them, the positive electrode sheet 100 includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode coating area and a positive electrode ear connected to the positive electrode coating area, the positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode ear is not coated with the positive electrode active material layer. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The negative electrode sheet 200 includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode coating area and a negative electrode ear connected to the negative electrode coating area, the negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode ear is not coated with a negative electrode active material layer. The material of the negative electrode current collector can be copper, and the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material can be carbon or silicon, etc.

[0040] The utility model also proposes a battery, which includes a battery cell. The specific structure of the battery cell refers to the above embodiment. Since the battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0041] Among them, the battery refers to a cup, trough or other container or part of a composite container that contains electrolyte solution and metal electrodes to generate current, and is a device that can convert chemical energy into electrical energy; the battery has positive and negative electrodes. With the advancement of science and technology, batteries generally refer to small devices that can generate electrical energy, such as solar cells. The performance parameters of batteries mainly include electromotive force, capacity, specific energy and resistance. Battery principle: In chemical batteries, the direct conversion of chemical energy into electrical energy is the result of spontaneous oxidation, reduction and other chemical reactions inside the battery, which are carried out on the two electrodes respectively. The negative electrode active material is composed of a reducing agent with a relatively negative potential and stable in the electrolyte, such as active metals such as zinc, cadmium, and lead, and hydrogen or hydrocarbons. The positive electrode active material is composed of an oxidizing agent with a relatively positive potential and stable in the electrolyte, such as metal oxides such as manganese dioxide, lead dioxide, and nickel oxide, oxygen or air, halogens and their salts, oxygen-containing acids and their salts, etc. The electrolyte is a material with good ionic conductivity, such as an aqueous solution of acid, alkali, or salt, an organic or inorganic non-aqueous solution, a molten salt, or a solid electrolyte.

[0042] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0043] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A cell isolation membrane structure, characterized in that: It comprises a substrate layer and a conductive coating; the substrate layer is provided with at least one straight section and at least one bent section; the straight section and the bent section are mutually staggered; at least part of the structure in the conductive coating is connected to the bent section.

2. The cell isolation membrane structure according to claim 1, characterized in that: The straight section is a straight position of the substrate layer in a wound state; the bent section is a corner position of the substrate layer in a wound state.

3. The cell isolation membrane structure according to claim 1 or 2, characterized in that: At least a portion of the structure in the conductive coating is connected to the straight section.

4. The cell isolation membrane structure according to claim 1 or 2, characterized in that: The conductive coating is covered and connected to the bending section.

5. The cell isolation membrane structure according to claim 4, characterized in that: The width of the conductive coating is equal to the width of the bending section; and / or, the relationship between the length L1 of the conductive coating and the length L2 of the bending section satisfies: L1≥L2.

6. The cell isolation membrane structure according to claim 5, characterized in that: The relationship between the length L1 of the conductive coating and the length L2 of the bending section satisfies: L1-L2=A; wherein A is 0.5 mm to 1.0 mm.

7. The cell isolation membrane structure according to claim 1 or 2, characterized in that: The width of the conductive coating is equal to the width of the bending section, and the thickness H1 of the conductive coating has a value range of H1=0.1 μm to 50 μm; the thickness H2 of the substrate layer has a value range of H2=1 μm to 50 μm.

8. The cell isolation membrane structure according to claim 1, characterized in that: The conductive coating is one of LATP material, LLZO material and LLTO material.

9. A battery cell, characterized in that: It comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the negative electrode sheet and the positive electrode sheet; and the positive electrode sheet, the separator and the negative electrode sheet are wound in sequence; the separator is the battery cell separator structure as described in any one of claims 1 to 8 above.

10. A battery, characterized in that: Comprising the battery cell as claimed in claim 9.

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