Composite isolating membrane structure, battery cell and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a composite isolating membrane structure, a battery cell and a battery, the composite isolating membrane structure comprises a base membrane and at least two coating composite layers; the coating composite layer is arranged on the surface of at least one side of the base film; the coating composite layer comprises a coating sub-layer and a convex sub-layer which are arranged in a laminated manner; the protrusions are connected to the base film in a layered mode. A blank concave area is arranged between every two adjacent protruding layers. According to the composite isolating membrane structure, the liquid retention capacity of a battery cell corresponding to the composite isolating membrane structure can be improved, the cycle life of the battery cell is favorably prolonged, and the use stability and safety are improved.

Description

Technical Field

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

[0002] In today's society, with the widespread use of electric vehicles and electronic products, lithium-ion batteries have become one of the important energy storage systems in modern society due to their high energy density, low self-discharge, long cycle life and environmental friendliness. At present, one of the important methods to improve the energy density of battery cells is to thin the isolation film.

[0003] However, the existing thinning of the diaphragm will also reduce the liquid retention capacity of the battery cell, thus affecting the service life of the battery cell. Utility Model Content

[0004] The utility model aims to provide a composite isolation membrane structure to improve the liquid retention capacity in view of the deficiencies of the prior art.

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

[0006] A composite isolation film structure comprises a base film and at least two coating composite layers; the coating composite layer is arranged on at least one side surface of the base film; and the coating composite layer comprises a coating layer and a protruding layer arranged in a stacked manner; the protruding layer is connected to the base film; and blank recessed areas are provided between adjacent protruding layers.

[0007] Preferably: on the same side surface of the base film, the coating composite layer is arranged along the length direction and / or width direction of the base film.

[0008] Preferably: the coated composite layer in the width direction of the first position of the base film is arranged between two adjacent coated composite layers in the width direction of the second position of the base film; and an assembly gap is provided between the coated composite layer in the width direction of the first position and the adjacent coated composite layer in the width direction of the second position;

[0009] And / or, the coated composite layer at the third position in the length direction of the base film is arranged between two adjacent coated composite layers at the fourth position in the length direction of the base film; and an installation gap is provided between the coated composite layer at the third position in the length direction and the adjacent coated composite layer at the fourth position in the length direction.

[0010] Preferably, a projection of the coating composite layer disposed on one surface of the base film toward the base film and a projection of the coating composite layer disposed on the other surface of the base film toward the base film at most partially overlap.

[0011] Preferably, a projection of the coating composite layer disposed on one surface of the base film toward the base film at least partially overlaps with a projection of the coating composite layer disposed on the other surface of the base film toward the base film.

[0012] Preferably: the relationship between the depth H1 of the blank recessed area disposed on one side of the surface of the base film and the depth H2 of the blank recessed area disposed on the other side of the surface of the base film satisfies: H1=H2;

[0013] And / or, the relationship between the depth of the base film and the sum of the depths H3 of the raised layers arranged on both sides of the base film, the depth H1 of the blank recessed area arranged on one side surface of the base film, and the depth H2 of the blank recessed area arranged on the other side surface of the base film satisfies: H3≥H1+H2+A; wherein A=3um~4um.

[0014] Preferably, the coating layer comprises a conductive coating layer and an adhesive layer, the conductive coating layer and the adhesive layer are stacked in sequence, and the conductive coating layer is connected to the protruding layer.

[0015] Preferably: the conductive coating layer is one of aluminum oxide, magnesium oxide, silicon oxide, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, magnesium nitride, tin dioxide, magnesium hydroxide and boehmite;

[0016] And / or, the adhesive layer is one of styrene-butadiene rubber, styrene-acrylic emulsion, acrylic emulsion, polyethyl acrylate, polymethyl methacrylate, polybutyl methacrylate, ethylene-vinyl acetate copolymer, polyvinyl acetate and polyurethane.

[0017] The utility model also discloses an electric core, comprising an anode sheet, a cathode sheet and an isolating film arranged between the anode sheet and the cathode sheet; the isolating film is the composite isolating film structure.

[0018] The utility model also discloses a battery, comprising the battery core.

[0019] The beneficial effect of the utility model lies in that the technical solution can effectively ensure the assembly stability between the composite isolation membrane structure and the pole piece by assembling the coating layer and the pole piece through the blank recessed area formed between adjacent raised layers, and can also form an effective space for storing electrolyte in the blank recessed area, thereby increasing the liquid retention of the battery cell corresponding to the composite isolation membrane structure in the case of the same thickness of the composite isolation membrane structure, and is beneficial to improving the cycle life of the battery cell and improving the stability and safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following will refer to the attached Figures 1 to 6 To describe the features, advantages and technical effects of exemplary embodiments of the present utility model.

[0021] Figure 1 This is a schematic structural diagram of a composite isolation membrane structure according to an embodiment of the utility model;

[0022] Figure 2 This is a schematic structural diagram of a composite isolation membrane structure according to an embodiment of the utility model;

[0023] Figure 3 A top view of a composite isolation membrane structure according to an embodiment of the present utility model;

[0024] Figure 4 This is a structural schematic diagram of a composite isolation membrane structure according to another embodiment of the utility model;

[0025] Figure 5 This is a structural schematic diagram of a composite isolation membrane structure according to another embodiment of the utility model;

[0026] Figure 6 It is a schematic structural diagram of a battery cell according to an embodiment of the utility model.

[0027] In the figure: 1-base film; 2-coating composite layer; 21-coating layer; 211-conductive coating layer; 212-adhesive layer; 22-convex layer; 3-blank recessed area. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship between the composite isolation membrane structure, the battery 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 associated objects before and after are an "or" relationship of a composite isolation membrane structure, a battery cell and a battery.

[0032] 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).

[0033] 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.

[0034] 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.

[0035] The following is combined with Figure 1 to Figure 6 The utility model is further described in detail, but it is not intended to limit the utility model.

[0036] like Figure 1As shown, in one embodiment of the utility model, the composite isolation film structure comprises a base film 1 and at least two coated composite layers 2; the coated composite layer 2 is arranged on at least one side surface of the base film 1; and the coated composite layer 2 comprises a stacked coating layer 21 and a raised layer 22; the raised layer 22 is connected to the base film 1; and a blank recessed area 3 is provided between adjacent raised layers 22.

[0037] The technical solution of the utility model can effectively ensure the assembly stability between the composite isolation membrane structure and the pole piece by assembling the coating layer and the pole piece through the blank recessed area formed between adjacent raised layers, and can also form an effective space for storing electrolyte in the blank recessed area, thereby increasing the liquid retention of the battery cell corresponding to the composite isolation membrane structure in the case of a composite isolation membrane structure of the same thickness, and is beneficial to improving the cycle life of the battery cell as well as improving the stability and safety of use.

[0038] Among them, the shape of the blank recessed area 3 is one of a regular triangle, a regular quadrilateral, and a regular hexagon that can be individually densely packed; the shape of the coated composite layer 2 is one of a regular triangle, a regular quadrilateral, and a regular hexagon that can be individually densely packed.

[0039] Specifically, in some embodiments, the coating layer 21 includes a conductive coating layer 211 and an adhesive layer 212, wherein Figure 2 As shown, the conductive coating layer 211 and the adhesive layer 212 are stacked in sequence, and the conductive coating layer 211 is connected to the protruding layer 22; the adhesive layer 212 is used for bonding and assembling with the pole piece. The adhesive layer 212 can effectively ensure the stability of the bonding and assembly of the coating layer 21 with the conductive coating layer 211 and the pole piece, respectively, and ensure the stability of the structure; and the conductive coating layer can effectively improve the conductivity of the electrolyte that penetrates. Among them, the conductive coating layer 211 and the adhesive layer 212 are mixed according to a parameter ratio of 2:1 or 3:1 or 4:1 or 6:1; this structure can ensure the rapidity of the production and processing of the coating layer, and can also reduce the coating process and improve the operating efficiency. Furthermore, the conductive coating layer 211 is one of materials such as aluminum oxide, magnesium oxide, silicon oxide, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, magnesium nitride, tin dioxide, magnesium hydroxide and boehmite; the bonding layer 212 is one of materials such as styrene-butadiene rubber, styrene-acrylic emulsion, acrylic emulsion, polyethyl acrylate, polymethyl methacrylate, polybutyl methacrylate, ethylene-vinyl acetate copolymer, polyvinyl acetate and polyurethane.

[0040] Specifically, in some embodiments, Figure 2As shown, the relationship between the depth H1 of the blank recessed area 3 located on one side of the surface of the base film 1 and the depth H2 of the blank recessed area 3 located on the other side of the surface of the base film 1 satisfies: H1=H2. The blank recessed areas 3 of the same depth can effectively ensure the uniformity of the structure after the isolation membrane structure and the pole piece are assembled, and ensure their stress conditions, thereby improving the stability of the structure. Among them, in some embodiments, H1≤2um, H2≤2um; this structure uses reasonable and smaller specifications to avoid the formation of excessive cavities in the recessed area due to electrolyte consumption in the later stage of the cycle, thereby improving the stability of the structure and the stability of use.

[0041] Specifically, in some embodiments, Figure 2 As shown, the relationship between the depth of the base film 1 and the sum of the depths of the convex layers 22 on both sides of the base film 1 H3, the depth H1 of the blank recessed area 3 on one side of the base film 1, and the depth H2 of the blank recessed area 3 on the other side of the base film 1 satisfies: H3≥H1+H2+A; wherein A=3um~4um. In other words, the tensile strength of the isolation film and the smoothness of the flow of the electrolyte can be guaranteed by a suitable depth difference.

[0042] Wherein, in some embodiments, Figure 1 and 2 As shown, the raised layer 22 is integrally fixedly formed with the base film 1. The raised layer 22 and the base film 1 formed integrally can effectively ensure the processing speed and the stability of the structure.

[0043] Specifically, in some embodiments, Figure 1 As shown, the number of the coating composite layers 2 is at least ten, and they are respectively arranged on two opposite side surfaces of the base film 1 .

[0044] Among them, in some embodiments, such as Figure 3 As shown, on the same side surface of the base film 1, the coating composite layers 2 are arranged in sequence and equidistantly along the length direction and / or width direction of the base film 1. That is to say, by arranging the coating composite layers arranged in sequence in the width direction and the length direction respectively, the flow space of the electrolyte can be further increased, and the space for storing the electrolyte is increased, so that the liquid retention of the battery cell can be increased and its conductive performance can be guaranteed. Furthermore, the coating composite layer 2 in the width direction of the first position D in the base film 1 is located between two adjacent coating composite layers 2 in the width direction of the second position C in the base film 1; and an assembly gap N is provided between the coating composite layer 2 in the width direction of the first position D and the adjacent coating composite layer 2 in the width direction of the second position C. That is, Figure 3As shown, the width L1 of the coated composite layer 2 + the width L2 of the coated composite layer 2 + the width L3 of the coated composite layer 2 < the width M of the base film 1 (composite isolation membrane structure). Furthermore, the coated composite layer 2 in the length direction of the third position in the base film 1 is located between two adjacent coated composite layers 2 in the length direction of the fourth position in the base film 1; and an installation gap is provided between the coated composite layer 2 in the length direction of the third position and the adjacent coated composite layers 2 in the length direction of the fourth position (not shown in the figure). Among them, the first position D, the second position C, the third position and the fourth position are any positions in the base film 1, respectively. In other words, the installation gap and the assembly gap N can effectively ensure that the electrolyte can quickly flow into the blank recessed area 3 when the isolation membrane structure is assembled; thereby forming an effective space for storing electrolyte and increasing the liquid retention of the battery cell.

[0045] Wherein, in other embodiments, Figure 4 and 5 As shown, on the same side surface of the base film 1, the coating composite layer 2 is covered on the base film 1 along the width direction of the base film 1; and the coating composite layers 2 are arranged in sequence and equidistantly along the length direction of the base film 1. In other words, by providing the coating composite layers arranged in sequence in the length direction, the flow space of the electrolyte can be further increased, and the space for storing the electrolyte is increased, so that the liquid retention of the battery cell can be increased and its conductive performance can be guaranteed.

[0046] Specifically, in some embodiments, the projection of the coating composite layer 2 on one side surface of the base film 1 toward the base film 1 and the projection of the coating composite layer 2 on the other side surface of the base film 1 toward the base film 1 at most partially overlap. Figure 2 As shown, the projection of the coated composite layer 2 located on one side surface of the base membrane 1 toward the base membrane 1 is staggered with the projection of the coated composite layer 2 located on the other side surface of the base membrane 1 toward the base membrane 1; that is, the coated composite layers 2 alternately arranged on both sides of the base membrane 1 can form more gaps for storing electrolyte, thereby ensuring that the battery cell has a higher liquid retention capacity under the same diaphragm thickness and improving the cycle life of the battery cell.

[0047] Specifically, in some other embodiments, the projection of the coating composite layer 2 on one side surface of the base film 1 toward the base film 1 and the projection of the coating composite layer 2 on the other side surface of the base film 1 toward the base film 1 at least partially overlap. Figure 5As shown, the projection of the coating composite layer 2 on one side of the base film 1 toward the base film 1 is overlapped with the projection of the coating composite layer 2 on the other side of the base film 1 toward the base film 1. That is, the coating composite layers 2 symmetrically arranged on both sides of the base film 1 can form a certain suitable gap for storing electrolyte, thereby ensuring that the battery cell has a higher liquid retention under the same diaphragm thickness and improving the cycle life of the battery cell.

[0048] The utility model also provides a battery cell, such as Figure 6 As shown, the battery cell includes an anode sheet 200, a cathode sheet 300 and an isolation membrane 100 arranged between the anode sheet 200 and the cathode sheet 300; the isolation membrane 100 is the above-mentioned composite isolation membrane structure, and the specific structure of the composite isolation membrane structure refers to the above-mentioned embodiment. Since this subject two 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.

[0049] The anode sheet 200 includes a positive electrode current collector and a positive electrode active material layer, 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 tab 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 tab is not coated with the positive electrode active material layer. The cathode sheet 300 includes a negative electrode current collector and a negative electrode active material layer, 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 tab 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 tab is not coated with a negative electrode active material layer.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 composite isolation membrane structure, characterized in that: It comprises a base film and at least two coating composite layers; the coating composite layer is arranged on at least one side surface of the base film; and the coating composite layer comprises a coating layer and a protrusion layer which are stacked; The raised layers are connected to the base film; and blank recessed areas are arranged between adjacent raised layers.

2. The composite isolation membrane structure according to claim 1, characterized in that: On the same side surface of the base film, the coating composite layer is arranged along the length direction and / or width direction of the base film.

3. The composite isolation membrane structure according to claim 2, characterized in that: The coated composite layer in the width direction of the first position of the base film is arranged between two adjacent coated composite layers in the width direction of the second position of the base film; and an assembly gap is provided between the coated composite layer in the width direction of the first position and the adjacent coated composite layer in the width direction of the second position; And / or, the coated composite layer at the third position in the length direction of the base film is arranged between two adjacent coated composite layers at the fourth position in the length direction of the base film; and an installation gap is provided between the coated composite layer at the third position in the length direction and the adjacent coated composite layer at the fourth position in the length direction.

4. The composite isolation membrane structure according to any one of claims 1 to 3, characterized in that: There is at most a partial overlap between the projection of the coating composite layer disposed on one surface of the base film toward the base film and the projection of the coating composite layer disposed on the other surface of the base film toward the base film.

5. The composite isolation membrane structure according to any one of claims 1 to 3, characterized in that: There is at least a partial overlap between a projection of the coating composite layer disposed on one surface of the base film toward the base film and a projection of the coating composite layer disposed on the other surface of the base film toward the base film.

6. The composite isolation membrane structure according to claim 1, characterized in that: The relationship between the depth H1 of the blank recessed area disposed on one side of the surface of the base film and the depth H2 of the blank recessed area disposed on the other side of the surface of the base film satisfies: H1=H2; And / or, the relationship between the depth of the base film and the sum of the depths H3 of the raised layers arranged on both sides of the base film, the depth H1 of the blank recessed area arranged on one side surface of the base film, and the depth H2 of the blank recessed area arranged on the other side surface of the base film satisfies: H3≥H1+H2+A; wherein A=3um~4um.

7. The composite isolation membrane structure according to claim 1, characterized in that: The coating layer comprises a conductive coating layer and an adhesive layer, the conductive coating layer and the adhesive layer are stacked in sequence, and the conductive coating layer is connected to the protruding layer.

8. The composite isolation membrane structure according to claim 7, characterized in that: The conductive coating layer is one of aluminum oxide, magnesium oxide, silicon oxide, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, magnesium nitride, tin dioxide, magnesium hydroxide and boehmite; And / or, the adhesive layer is one of styrene-butadiene rubber, styrene-acrylic emulsion, acrylic emulsion, polyethyl acrylate, polymethyl methacrylate, polybutyl methacrylate, ethylene-vinyl acetate copolymer, polyvinyl acetate and polyurethane.

9. A battery cell, characterized in that: It comprises an anode sheet, a cathode sheet and an isolation membrane arranged between the anode sheet and the cathode sheet; the isolation membrane is a composite isolation membrane 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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