A lithium battery soft-pack laminated cell

Abstract

The present application provides a lithium battery soft-pack laminated cell, which relates to the technical field of lithium batteries and includes a current collector, a coating material, an edge coating layer having an insulating adhesive material, and a protective layer having an insulating film material. The coating material is coated on the center of both sides of the current collector, the edge coating layer is coated on both sides of both sides of the current collector, and the protective layer is arranged at both ends of the current collector. Two corresponding protective layers form a group of R-corner protection groups, and a plurality of R-corner protection groups are arranged equidistantly in the longitudinal extension direction of the current collector; extensions extending to the edge coating layer are provided at both ends of the protective layer, and the extensions are pressed onto the surface of the edge coating layer, and a plurality of small holes are opened on the surface of the extensions, and the adhesive material in the edge coating layer is deformed and extended into the small holes, so that the edge of the cell is wrapped by the R-corner protection group to prevent the R corner of the pole piece from scratching the aluminum-plastic film, thereby reducing the risk of damage to the aluminum-plastic film.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and more specifically, to a lithium battery soft-pack laminated cell. Background Art

[0002] Soft-pack lithium batteries are simply liquid lithium-ion batteries encased in a polymer shell. They are packaged in aluminum-plastic film, and in the event of a safety hazard, the worst that can happen is bulging and cracking.

[0003] Lithium-ion battery electrodes are mainly composed of a current collector, an active material layer, and an edge functional layer. Generally, aluminum foil or carbon-coated aluminum foil is used as the current collector for the positive electrode, and copper foil is used as the current collector for the negative electrode.

[0004] Among them, the edge reinforcement layer coated on the edge of the lithium-ion battery electrode can not only enhance the electrode's compressive strength, but also reduce the risk of short circuit. The raw materials used in traditional edge coating are mainly boehmite, which has poor tensile toughness.

[0005] After the pole pieces are stacked into bare cells, they are bent into multiple R angles, and the boehmite position is bent, which is prone to material falling off, directly affecting the performance of the battery.

[0006] There are multiple R corners bent in the laminated battery cells. When making soft-pack batteries, the sharp corners still have tiny burrs after slicing, which causes the R corners of the pole pieces to scratch the aluminum-plastic film during the assembly process. There is a risk of damage to the aluminum-plastic film, resulting in electrolyte leakage during the subsequent liquid injection.

[0007] Application Contents

[0008] The technical problem to be solved by the present application is that in conventional soft-pack laminated cells, the R corner of the pole piece scratches the aluminum-plastic film. In view of the problems existing in the prior art, a lithium battery soft-pack laminated cell is provided.

[0009] The purpose and effect of this application are achieved by the following specific technical means:

[0010] A lithium battery soft-pack laminated cell, comprising a current collector, a coating material, an edge coating layer having an insulating adhesive material, and a protective layer having an insulating film material;

[0011] A coating material is applied to the center of both sides of the current collector;

[0012] Edge coating, applied on both sides of the current collector;

[0013] The protective layers are multiple and greater in number and are arranged at both ends of the current collector. Two corresponding protective layers form a group of R-angle protection groups. Several R-angle protection groups are arranged equidistantly in the longitudinal extension direction of the current collector.

[0014] In a further preferred embodiment, the edge coating material is selected from the group consisting of: a chemically cross-linked water-insoluble polymer, N-methylpyrrolidone or deionized water, and a colorant.

[0015] A further preferred embodiment: the chemically cross-linked water-insoluble polymer is selected from one and / or more of fluoroplastics, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVF), polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FRP), soluble polytetrafluoroethylene (PFA), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrachloroethylene copolymer (ETFE), polyimide resin (PI), cycloolefin copolymer (COC), polyacrylic acid or styrene-butadiene rubber or polyamide or polyterephthalate, their derivatives, their cross-linked products and their copolymers.

[0016] A further preferred embodiment: the colorant is selected from one and / or more of carbon black, cobalt blue, ultramarine, iron oxide, cadmium red, chrome orange, molybdenum orange, cadmium yellow, chrome yellow, nickel titanium yellow, titanium white, lithopone, zinc white, phthalocyanine pigments, azo pigments, anthraquinone pigments, indigo pigments and metal complex pigments.

[0017] A further preferred embodiment: the thickness of the edge coating layer is 100 μm-500 μm.

[0018] A further preferred embodiment: the current collector also includes a support layer arranged between the current collector and the coating material, and the support layer is at least one of a conductive carbon material and a metal material; wherein the conductive carbon material is selected from zero-dimensional conductive carbon, including acetylene black and conductive carbon black; one-dimensional conductive carbon, including carbon nanotubes; two-dimensional conductive carbon, including conductive graphite and graphene; three-dimensional conductive carbon, including at least one of reduced graphene oxide; the metal material is selected from at least one of aluminum powder, iron powder and silver powder.

[0019] A further preferred solution is that the protective layer is arranged in a concave shape at the edge of the current collector, and the protective layer is bonded to the side section of the current collector.

[0020] A further preferred solution is that the protective layer is provided with extension parts extending to the edge coating layer at both ends, and the extension parts are pressed onto the surface of the edge coating layer, a plurality of small holes are opened on the surface of the extension parts, and the glue material in the edge coating layer is deformed and extends into the small holes.

[0021] A further preferred solution: the thickness of the extension portion is 1 μm-300 μm.

[0022] A further preferred solution is that the width of the edge coating layer covered by the extension portion is greater than or equal to two-thirds of the width of the edge coating layer.

[0023] Beneficial effects of this application:

[0024] 1. The insulating edge coating is more resilient than the traditional boehmite edge coating and can improve the tensile resistance of the current collector. The insulating edge coating can prevent the burrs generated during the cutting process of the current collector from piercing the separator. It improves the problem of traditional boehmite edge coating and ceramic coating being brittle after drying and ceramic particles easily causing the tape to break during rolling, resulting in a large amount of waste. The use of insulating edge coating can improve production efficiency;

[0025] 2. The protective layer is attached to both ends of the current collector by the glue sticking equipment. The material of the side coating layer will deform and squeeze into the small holes. Multiple small holes form multiple fixed points, which greatly improves the connection strength. During the later transmission process, the side coating layer cools and hardens. The side coating layer squeezed into the small holes can be firmly attached to the inner wall of the small holes, preventing the protective layer from falling off. The characteristics of the side coating layer and the protective layer are used to connect the two.

[0026] 3. Multiple groups of R-angle protection groups are equidistantly arranged in the longitudinal extension direction of the current collector. The pole pieces are laminated with the R-angle protection groups as the lamination edges, so the edge coating of the glue is not easy to fall off;

[0027] 4. Protect the edge coating with the R corner protection group. When assembling the aluminum-plastic film later, wrap the edge of the battery cell with the R corner protection group to prevent the R corner of the pole piece from scratching the aluminum-plastic film, reduce the risk of damage to the aluminum-plastic film, and effectively ensure the quality of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present application will be further described below with reference to the accompanying drawings.

[0029] Figure 1 A schematic diagram of the overall structural combination of this application (flattened);

[0030] Figure 2 This is a schematic diagram of the overall structural combination of this application (stacked state);

[0031] Figure 3 Schematic diagram of the current collector and protective layer structure combination of this application;

[0032] Figure 4 Schematic diagram of the combination structure of the edge coating layer and the protective layer of this application;

[0033] Figure 5 For this application Figure 1 A local enlarged structural diagram in FIG.

[0034] Figure 6 This is a schematic diagram of the protective layer structure of this application.

[0035] Figures 1-6 Middle: current collector (1), coating material (101), edge coating (102), protective layer (2), extension (201), small hole (202). DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned objectives, features and advantages of this application, Figures 1-6 The present application is further described in detail in the following embodiments. The following embodiments are merely examples of implementing the present application. It should be noted that the disclosed embodiments do not limit the scope of the present application. On the contrary, modifications and improvements made without departing from the scope of the present application are within the scope of patent protection of the present application.

[0037] See also Figure 4 A lithium battery soft-pack laminated cell comprises a current collector 1, a coating material 101, a side coating layer 102 having an insulating adhesive material, and a protective layer 2 having an insulating film material;

[0038] The current collector 1 further includes a support layer disposed between the current collector 1 and the coating material 101, and the support layer is at least one of a conductive carbon material and a metal material; wherein the conductive carbon material is selected from zero-dimensional conductive carbon, including acetylene black and conductive carbon black; one-dimensional conductive carbon, including carbon nanotubes; two-dimensional conductive carbon, including conductive graphite and graphene; three-dimensional conductive carbon, including at least one of reduced graphene oxide; the metal material is selected from at least one of aluminum powder, iron powder and silver powder;

[0039] Furthermore, the supporting layer is coated on the current collector 1 to form a carbon-coated foil, and the supporting layer is preferably made of conductive carbon material. The electron transmission efficiency can be improved by the supporting layer. The current collector 1 foil before the current collector 1 is coated can be called a bare foil. Because the surface of the bare foil is smooth, if the coating 101 is directly coated on the surface of the bare foil, it will cause the impedance of the coating 101 to increase when it is directly attached to the interface of the foil surface, and the coating 101 is prone to powdering. If the supporting layer is first coated on the bare foil to form a carbon-coated foil, then friction will be generated between the coating 101 and the supporting layer during coating, and the coating between the coating 101 and the current collector 1 can be tighter, thereby improving the coating quality.

[0040] See also Figure 4 When the current collector 1 is aluminum foil, the coating material 101 is the positive electrode active material layer; when the current collector 1 is copper foil, the coating material 101 is the negative electrode active material layer. The coating material 101 is applied to the center of both sides of the current collector 1. The coating method of the coating material 101 is continuous or intermittent.

[0041] Furthermore, the edge coating layer 102 is coated on both sides of the current collector 1;

[0042] Specifically, the edge coating 102 material is selected from: a chemically cross-linked water-insoluble polymer, N-methylpyrrolidone or deionized water, and a colorant;

[0043] Specifically, the chemically cross-linked water-insoluble polymer is selected from one and / or more of fluoroplastics, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVF), polytetrafluoroethylene (PTFE), polyperfluoroethylene propylene (FRP), soluble polytetrafluoroethylene (PFA), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrachloroethylene copolymer (ETFE), polyimide resin (PI), cyclic olefin copolymer (COC), polyacrylic acid or styrene-butadiene rubber or polyamide or polyterephthalate, their derivatives, their cross-linked products and their copolymers;

[0044] Furthermore, the coloring material is selected from one and / or more of carbon black, cobalt blue, ultramarine, iron oxide, cadmium red, chrome orange, molybdenum orange, cadmium yellow, chrome yellow, nickel titanium yellow, titanium dioxide, lithopone, zinc white, phthalocyanine pigments, azo pigments, anthraquinone pigments, indigo pigments and metal complex pigments;

[0045] The edge coating 102 is prepared as follows:

[0046] S1: Glue making

[0047] A chemically cross-linked water-insoluble polymer, N-methylpyrrolidone or deionized water, and a colorant are prepared. The chemically cross-linked water-insoluble polymer is exemplified by a fluoroplastic, with a ratio of 5%-30% fluoroplastic and 70%-95% N-methylpyrrolidone or deionized water. The prepared materials are placed in a blender at room temperature and a high dew point, and stirred for 2-4 hours to form a glue, thereby obtaining an insulating edge coating 102.

[0048] S2: Coloring of rubber compound

[0049] After the stirring time is over, 0.2%-1% of coloring material is added, and the coloring material is added to the mixer and blended with the insulating edge coating 102 obtained in S1, and stirred again for 2H-4h. After the stirring time is over, the colored insulating edge coating 102 is obtained.

[0050] The steps for applying the edge coating 102 are as follows:

[0051] Using a continuous or intermittent coating device to apply a colored insulating side coating 102 to both sides of the current collector 1 to form a side coating 102;

[0052] Furthermore, the insulating edge coating 102 is tougher than the traditional boehmite edge coating, and can improve the tensile strength of the current collector 1. The insulating edge coating 102 generates less dust during the production process, which is beneficial to maintaining the production environment. The edge coating position of the current collector 1 is smoother and less prone to burrs and beads. The main function of the colorant is to make the insulating edge coating 102 colorable, making it easier to identify the position of the edge coating 102 in the subsequent lithium battery processing stage.

[0053] During the subsequent transmission and rolling process of the pole piece, the insulating edge coating 102 can greatly reduce the pole piece's breakage rate.

[0054] The thickness of the edge coating 102 is 100 μm-500 μm. The insulating edge coating 102 can prevent burrs generated during the cutting process of the current collector 1 from piercing the separator. This improves the problem of traditional boehmite edge coatings and ceramic coatings being brittle after drying and ceramic particles easily causing tape breakage during rolling, resulting in a large amount of waste. The use of the insulating edge coating 102 can improve production efficiency.

[0055] Compared with the pole pieces coated with boehmite edge coating and ceramic coating, the pole pieces coated with insulating edge coating 102 have a significantly lower detection rate of burrs during die-cutting. Moreover, when the battery cell is overcharged or impacted, causing the battery temperature to rise, the edge coating 102 increases the contact internal resistance of the battery at high temperature, which can play an insulating role and provide better safety and stability.

[0056] See also Figures 1-6 , protective layers 2, the number of which is greater than one, are provided at both ends of the current collector 1, two corresponding protective layers 2 form a group of R corner protection groups, and the current collector 1 is provided with a plurality of R corner protection groups arranged equidistantly in the longitudinal extension direction;

[0057] A gluing device is set at the rear section of the electrode baking oven. When the electrode is output from the baking oven, the gluing device sticks the protective layer 2 to the two ends of the collector 1. The protective layer 2 is concave and covers the edge of the collector 1. The opposite surface of the protective layer 2 is provided with adhesive so that the protective layer 2 is bonded to the side section of the collector 1. The two ends of the protective layer 2 are provided with extensions 201 extending to the side coating 102. The extension 201 is pressed on the surface of the side coating 102. Because a number of small holes 202 are opened on the surface of the extension 201, and the side coating 102 made of adhesive material is hot-melted after baking, the surface of the side coating 102 is hot-melted. When the extension portion 201 is softened and pressed against the edge coating layer 102, the protective layer 2 is made of a plastic film, thereby improving the connectivity between the extension portion 201 and the edge coating layer 102. The material of the edge coating layer 102 deforms and squeezes into the small holes 202. The multiple small holes 202 form multiple fixed points, greatly improving the connection strength. During the subsequent transmission process, the edge coating layer 102 cools and hardens, and the edge coating layer 102 squeezed into the small holes 202 can be firmly attached to the inner wall of the small holes 202, preventing the protective layer 2 from falling off. The characteristics of the edge coating layer 102 and the protective layer 2 are used to connect the two.

[0058] The thickness of the extension portion 201 is 1 μm-300 μm, and the width of the extension portion 201 covering the edge coating 102 is greater than or equal to two-thirds of the width of the edge coating 102. The extension portion 201 has good connectivity with the edge coating 102, and the extension portion 201 is relatively thick, and has good tensile strength.

[0059] Multiple groups of R-corner protection groups are equidistantly arranged in the longitudinal extension direction of the current collector 1. The pole pieces are stacked with the R-corner protection groups as the stacking edges. The glue edge coating 102 is not easy to fall off, and the edge coating 102 is protected by the R-corner protection groups. When the aluminum-plastic film is assembled later, the edge of the battery cell is wrapped by the R-corner protection groups to prevent the pole piece R corner from scratching the aluminum-plastic film, reduce the risk of damage to the aluminum-plastic film, and effectively ensure the quality of the battery cell.

Claims

1. A lithium battery soft-pack laminated cell, characterized by: It includes a current collector, a coating material, an edge coating layer having an insulating adhesive material, and a protective layer having an insulating film material; A coating material is applied to the center of both sides of the current collector; Side coating, coated on both sides of the current collector, the thickness of the side coating is 100μm-500μm; Protective layers, the number of which is greater than one, are arranged at both ends of the current collector, and two corresponding protective layers form a group of R-corner protection groups. Several R-corner protection groups are arranged equidistantly in the longitudinal extension direction of the current collector. The protective layer is concavely arranged at the edge of the current collector, and the protective layer is bonded to the side section of the current collector. Extensions extending to the edge coating are provided at both ends of the protective layer, and the extensions are pressed onto the surface of the edge coating. Several small holes are opened on the surface of the extension, and the glue material in the edge coating is deformed and extends into the small holes. The thickness of the extension is 1μm-300μm, and the width of the edge coating covered by the extension is ≥ two-thirds of the width of the edge coating.

2. The lithium battery soft-pack laminated cell according to claim 1, characterized in that: The edge coating material is selected from the group consisting of: a chemically cross-linked water-insoluble polymer, N-methylpyrrolidone or deionized water, and a colorant.

3. The lithium battery soft-pack laminated cell according to claim 2, characterized in that: The chemically cross-linked water-insoluble polymer is selected from one or more of fluoroplastics, polyvinylidene fluoride, polyvinyl chloride, polytetrafluoroethylene, polyperfluoroethylene propylene, soluble polytetrafluoroethylene, polychlorotrifluoroethylene, ethylenechlorotrifluoroethylene copolymer, ethylene-tetrachloroethylene copolymer, polyimide resin, cycloolefin copolymer, polyacrylic acid or styrene-butadiene rubber or polyamide or polyterephthalate, their derivatives, their cross-linked products or their copolymers.

4. The lithium battery soft-pack laminated cell according to claim 2, characterized in that: The coloring material is selected from one or more of carbon black, cobalt blue, ultramarine, iron oxide, cadmium red, chrome orange, molybdenum orange, cadmium yellow, chrome yellow, nickel titanium yellow, titanium white, lithopone, zinc white, phthalocyanine pigments, azo pigments, anthraquinone pigments, indigo pigments and metal complex pigments.

5. The lithium battery soft-pack laminated cell according to claim 1, characterized in that: The current collector also includes a support layer arranged between the current collector and the coating material, and the support layer is at least one of a conductive carbon material and a metal material; wherein the conductive carbon material is selected from zero-dimensional conductive carbon, including acetylene black and conductive carbon black; one-dimensional conductive carbon, including carbon nanotubes; two-dimensional conductive carbon, including conductive graphite and graphene; three-dimensional conductive carbon, including at least one of reduced graphene oxide; the metal material is selected from at least one of aluminum powder, iron powder and silver powder.

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