Aluminum plastic film and lithium ion battery thereof

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to an aluminum-plastic film and a lithium ion battery thereof, the aluminum-plastic film comprises an outer layer, a first bonding layer, a heat conduction layer, a second bonding layer and a sealing layer which are sequentially stacked, the heat conduction layer comprises a metal bending sheet and a first heat conduction material, the metal bending sheet is arranged in the heat conduction layer, and a gap between the metal bending sheet and the heat conduction layer is filled with the first heat conduction material; the outer layer is filled with a first heat conduction material, and / or the first bonding layer is filled with a second heat conduction material. By optimizing the structure of the aluminum-plastic film, the heat transfer rate of the aluminum-plastic film can be improved, and the overall heat dissipation effect of the aluminum-plastic film can be improved, so that the performance of the battery cell hot box is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to an aluminum plastic film and a lithium ion battery thereof. Background Art

[0002] Nowadays, lithium ion batteries have the advantages of large energy density and power density, high working voltage, light weight, small volume, long cycle life, good safety, environmental friendliness, etc., and have broad application prospects in portable electrical appliances, power tools, large-scale energy storage, electric vehicle power sources, etc.

[0003] Under the conditions of battery abuse, such as overcharging, over-discharging, short circuit, extrusion, puncture, high temperature, etc., lithium ion batteries may catch fire, explode and other dangers. Therefore, the safety performance requirements for lithium ion batteries in all aspects are getting higher and higher. In particular, the thermal box performance is an important indicator. The thermal box test is often carried out at high temperature, and the heat generation rate of the lithium ion battery is greater than the heat dissipation rate, resulting in thermal runaway of the battery.

[0004] In the process of realizing the present utility model, the inventor found that there are at least the following problems in the prior art

[0005] The prior art copes with battery thermal runaway by changing the composition of electrolyte additives, but cannot guarantee the low temperature performance of the battery core. Summary of the Utility Model

[0006] One of the purposes of the present utility model is to provide an aluminum plastic film aiming at the deficiencies of the prior art. By optimizing the structure of the aluminum plastic film, the heat transfer rate of the aluminum plastic film can be improved, which helps to enhance the overall heat dissipation effect of the aluminum plastic film, thereby improving the thermal box performance of the battery core.

[0007] In order to achieve the above purpose, the present utility model adopts the following technical solutions:

[0008] An aluminum plastic film, comprising an outer layer, a first adhesive layer, a heat conducting layer, a second adhesive layer and a sealing layer which are sequentially laminated; the heat conducting layer includes metal bending pieces and a first heat conducting material, the metal bending pieces are arranged in the heat conducting layer, and the first heat conducting material fills the gaps between the metal bending pieces and the heat conducting layer; the outer layer is filled with a first heat conducting material, and / or the first adhesive layer is filled with a second heat conducting material.

[0009] Preferably, the cross-sectional shape of the metal bending piece is wavy, stepped, semi-circular or pier-shaped.

[0010] Preferably, the cross section of part of the metal bending pieces is bent into an arc, and the radius of the arc is 0.5 μm to 1.5 μm.

[0011] Preferably, the first heat-conducting material is glass fiber, carbon fiber, heat-conducting ceramic sheet or heat-conducting silica gel.

[0012] Preferably, the second heat-conducting material is metal particles or non-metal particles.

[0013] Preferably, the second heat-conducting material is silicon particles, aluminum particles, magnesium particles or diamond particles.

[0014] Preferably, the outer layer is a nylon layer, the sealing layer is a PP layer, and the metal bending piece is an aluminum sheet.

[0015] Preferably, the metal bending piece extends along the length direction or the width direction of the heat-conducting layer.

[0016] Preferably, the projection of the metal bending piece and the heat-conducting layer in the thickness direction partially overlaps.

[0017] The second object of the present utility model is to provide a lithium-ion battery, including the above-mentioned aluminum plastic film.

[0018] One of the above technical solutions has the following beneficial effects

[0019] By optimizing the structure of the aluminum plastic film, the present utility model designs the metal bending piece into a preset two-dimensional shape. In the same length direction, compared with the flat aluminum layer of the existing aluminum plastic film, the metal bending piece has an increased specific surface area. At the same time, the first heat-conducting material is filled in the area outside the metal bending piece, and the metal bending piece contacts the first heat-conducting material, which can improve the overall heat dissipation capacity of the heat-conducting layer. In addition, filling the first heat-conducting material in the outer layer can improve the problem of poor heat dissipation of the nylon layer of the existing aluminum plastic film. The first adhesive layer is filled with the second heat-conducting material, which can improve the heat transfer rate from the heat-conducting layer to the outer layer, and helps to improve the overall heat dissipation effect of the aluminum plastic film. Description of the Drawings

[0020] The features, advantages and technical effects of the exemplary embodiments of the present utility model will be described below with reference to the drawings.

[0021] Figure 1 It is a schematic cross-sectional structure diagram of Embodiment 1 in the present utility model.

[0022] Figure 2 It is a schematic cross-sectional structure diagram of Embodiment 2 in the present utility model.

[0023] Figure 3 It is a schematic cross-sectional structure diagram of Embodiment 3 in the present utility model.

[0024] Figure 4 It is a schematic cross-sectional structure diagram of Embodiment 4 in the present utility model.

[0025] Figure 5This is a schematic cross-sectional structure diagram of Embodiment 5 in the present utility model.

[0026] Figure 6 This is a schematic cross-sectional structure diagram of Embodiment 6 in the present utility model.

[0027] Figure 7 This is a schematic cross-sectional structure diagram of Embodiment 7 in the present utility model.

[0028] Among them, the reference numerals are explained as follows:

[0029] 1 - Outer layer;

[0030] 2 - First adhesive layer;

[0031] 3 - Heat-conducting layer; 31 - Metal bending piece;

[0032] 4 - Sealing layer;

[0033] 5 - Second adhesive layer. Detailed implementation manners

[0034] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" is an open-ended term and should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0035] In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In the utility model, unless otherwise clearly specified and defined, terms such as "installed", "connected", "connected", "fixed", etc. 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0037] The following further elaborates on the present utility model in conjunction with the accompanying drawings, but does not limit the present utility model.

[0038] Embodiment 1

[0039] Since the existing technology addresses battery thermal runaway by changing the composition of the electrolyte additive, it cannot guarantee the low-temperature performance of the battery cells.

[0040] The aluminum-plastic film of the present utility model includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 that are sequentially laminated; the heat-conducting layer 3 includes metal bending pieces 31 and a first heat-conducting material. The metal bending pieces 31 are arranged inside the heat-conducting layer 3, and the first heat-conducting material fills the gaps between the metal bending pieces 31 and the heat-conducting layer 3; the outer layer 1 is filled with the first heat-conducting material, and the first adhesive layer 2 is filled with a second heat-conducting material. By optimizing the structure of the aluminum-plastic film, the present utility model designs the metal bending pieces 31 into a preset two-dimensional shape. In the same length direction, compared with the flat aluminum layer of the existing aluminum-plastic film, the metal bending pieces 31 have an increased specific surface area. At the same time, the first heat-conducting material is filled in the area outside the metal bending pieces 31, and the metal bending pieces 31 are in contact with the first heat-conducting material, which can improve the overall heat dissipation ability of the heat-conducting layer 3. In addition, the outer layer 1 is filled with the first heat-conducting material, which can improve the problem of poor heat dissipation of the nylon layer of the existing aluminum-plastic film. The first adhesive layer 2 is filled with the second heat-conducting material, which can improve the heat transfer rate from the heat-conducting layer 3 to the outer layer 1, contributing to improving the overall heat dissipation effect of the aluminum-plastic film.

[0041] In the aluminum-plastic film according to the present utility model, the cross-sectional shape of the metal bending pieces 31 is wavy, stepped, semi-circular, or pier-shaped. Specifically, the cross-sectional shape of the metal bending pieces 31 is one or more of wavy, stepped, semi-circular, and pier-shaped; in this embodiment, it is preferably wavy, and the wavy shape has multiple wave peaks, and the first heat-conducting material is filled at the wave peaks.

[0042] In the aluminum-plastic film according to the present utility model, part of the cross-section of the metal bending pieces 31 is bent into an arc, and the radius of the arc is 0.5 μm to 1.5 μm. For example, the radius of the arc is designed to be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc. Compared with the flat aluminum layer of the existing aluminum-plastic film, it can increase the specific surface area, and the surface area of the metal bending pieces 31 is 1.5 to 3 times that of the flat aluminum layer.

[0043] In the aluminum-plastic film according to the present utility model, the first heat-conducting material is glass fiber, carbon fiber, heat-conducting ceramic sheet, or heat-conducting silica gel. Specifically, the present utility model can use one of glass fiber, carbon fiber, and heat-conducting ceramic sheet and mix it with heat-conducting silica gel to form the first heat-conducting material. The role of the heat-conducting silica gel is to fully fill the gaps or voids between different functional layers and improve the heat dissipation efficiency. The present utility model preferably uses carbon fiber, and its thermal conductivity is 400 to 700 W / m·K.

[0044] In the aluminum-plastic film according to the present utility model, the second heat-conducting material may be metal particles or non-metal particles. The second heat-conducting material may be one or more of silicon particles, aluminum particles, magnesium particles or diamond particles, without limitation here.

[0045] In the aluminum-plastic film according to the present utility model, the outer layer 1 is a nylon layer, the sealing layer 4 is a PP layer (polypropylene layer), and the metal bending piece 31 is an aluminum sheet. Specifically, the outer layer 1 is a mixed layer of a nylon layer and the first heat-conducting material. The metal bending piece 31 is preferably an aluminum sheet, and may also be other metal materials, without limitation here.

[0046] In the aluminum-plastic film according to the present utility model, the metal bending piece 31 extends along the length direction or the width direction of the heat-conducting layer 3. In this embodiment, the metal bending piece 31 extends along the length direction or the width direction of the heat-conducting layer 3. The overall length and width of the metal bending piece 31 are the same as the length and width of the adjacent first adhesive layer 2 and the sealing layer 4, which helps to further increase the specific area and achieve the improvement of the heat dissipation capacity of the heat-conducting layer 3. Among them, the projections of the metal bending piece 31 and the heat-conducting layer 3 in the thickness direction completely overlap, that is, the heat-conducting layer 3 can completely cover the metal bending piece 31, and the projected areas of the two are approximately the same. However, the present utility model is not limited thereto. In some embodiments, the projections of the metal bending piece 31 and the heat-conducting layer 3 in the thickness direction may also partially overlap, and the projected area of the heat-conducting layer 3 is slightly larger, which can meet the heat dissipation performance requirements of different battery structures.

[0047] The working principle of the present utility model is:

[0048] By optimizing the structure of the aluminum-plastic film, the present utility model designs the metal bending piece 31 into a preset two-dimensional shape. In the same length direction, the metal bending piece 31 increases the specific surface area compared with the flat aluminum layer of the existing aluminum-plastic film. At the same time, the first heat-conducting material is filled in the area outside the metal bending piece 31. The contact between the metal bending piece 31 and the first heat-conducting material can improve the overall heat dissipation capacity of the heat-conducting layer 3. In addition, the first heat-conducting material is filled in the outer layer 1, which can improve the problem of poor heat dissipation of the nylon layer of the existing aluminum-plastic film. The second heat-conducting material is filled in the first adhesive layer 2, which can improve the heat transfer rate from the heat-conducting layer 3 to the outer layer 1, and helps to improve the overall heat dissipation effect of the aluminum-plastic film.

[0049] The lithium-ion battery according to the embodiment of the present utility model includes a battery cell, which includes a first electrode sheet, a separator, and a second electrode sheet. The first electrode sheet, the separator, and the second electrode sheet are wound in sequence. The battery is encapsulated with an aluminum-plastic film, and electrode tabs are respectively provided on the first electrode sheet and the second electrode sheet. In order to avoid short circuit between the positive and negative electrode sheets, a separator is provided between every two adjacent electrode sheets, and the electrode sheets with opposite polarities are electrically isolated through the separator. The first electrode sheet can be a positive electrode sheet or a cathode sheet, and the second electrode sheet can be a negative electrode sheet or an anode sheet; or, the first electrode sheet can be a negative electrode sheet or an anode sheet, and the second electrode sheet can be a positive electrode sheet or a cathode sheet, which is not limited here.

[0050] The lithium-ion battery according to the embodiment of the present utility model can also be used in different electrical devices. The electrical devices can be automobiles, mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, and electric tools, etc. The automobiles can be fuel vehicles, gas vehicles, or new energy vehicles. The new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; The spacecrafts include airplanes, rockets, space shuttles, and spaceships, etc.; The electric toys include fixed or mobile electric toys, for example, game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc.; The electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not make special restrictions on the above-mentioned electrical devices.

[0051] It should be noted that: the battery cell in this embodiment is formed by winding an anode sheet, a cathode sheet, and a separator. The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) stacked in sequence. Among them, the metal bending piece 31 in the heat-conducting layer 3 is arranged in a wave shape. The first heat-conducting material is composed of carbon fiber and silica gel and is coated on the surface of the metal bending piece 31. The outer layer 1 is made of a mixture of heat-conducting materials carbon fiber, silica gel, and nylon; The first adhesive layer 2 is formed by adding non-metallic silicon particles.

[0052] Embodiment 2

[0053] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) stacked in sequence. Among them, the metal bending piece 31 in the heat-conducting layer 3 is arranged in a wave shape. The first heat-conducting material is composed of carbon fiber and silica gel and is coated on the surface of the metal bending piece 31. The outer layer 1 is made of a mixture of heat-conducting materials carbon fiber, silica gel, and nylon.

[0054] Other structures are the same as those in Embodiment 1 and will not be described in detail here.

[0055] Embodiment 3

[0056] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) that are laminated in sequence. Among them, the metal bending piece 31 in the heat-conducting layer 3 is arranged in a wavy shape. The first heat-conducting material is composed of carbon fiber and silica gel and is coated on the surface of the metal bending piece 31. The first adhesive layer 2 is formed by adding non-metallic silicon particles.

[0057] The other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0058] Embodiment 4

[0059] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) that are laminated in sequence. Among them, the outer layer 1 is made of a mixture of the heat-conducting materials carbon fiber, silica gel, and nylon; the first adhesive layer 2 is formed by adding non-metallic silicon particles.

[0060] The other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0061] Embodiment 5

[0062] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) that are laminated in sequence. Among them, the metal bending piece 31 in the heat-conducting layer 3 is arranged in a wavy shape. The first heat-conducting material is composed of carbon fiber and silica gel and is coated on the surface of the metal bending piece 31.

[0063] The other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0064] Embodiment 6

[0065] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) that are laminated in sequence. Among them, the outer layer 1 is made of a mixture of the heat-conducting materials carbon fiber, silica gel, and nylon.

[0066] The other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0067] Embodiment 7

[0068] The aluminum-plastic film of this embodiment includes an outer layer 1, a first adhesive layer 2, a heat-conducting layer 3, a second adhesive layer 5, and a sealing layer 4 (PP layer) that are laminated in sequence. Among them, the first adhesive layer 2 is formed by adding non-metallic silicon particles.

[0069] The other structures are the same as those in Embodiment 1 and will not be elaborated here.

[0070] Comparative Example 1

[0071] Differences from the first embodiment: In this embodiment, a conventional aluminum-plastic film structure is adopted; the aluminum-plastic film is composed of a nylon layer, an adhesive layer, an aluminum layer, an adhesive layer, and a sealing layer (PP layer).

[0072] The thermal box performance tests were carried out on the battery cores of Examples 1-7 and Comparative Example 1. First, the battery cores were placed at room temperature and charged at a constant current and constant voltage of 0.5C to 4.53V, with a cut-off at 0.05C. Then, the battery cores were placed in an incubator and heated at a rate of 5°C / min to a preset temperature (such as 128°C, 130°C, 132°C, 135°C, etc.), and kept for 60 minutes before stopping, while monitoring the surface temperature of the battery cores in real time. If the battery cores do not catch fire or explode, they pass the test.

[0073] Table 1. Comparison table of thermal box performance tests of the battery cores of Examples 1-7 and Comparative Example 1

[0074] 128℃ 130℃ 132℃ 135℃ Example 1 3 / 3 pass 3 / 3 pass 3 / 3 pass 3 / 3 pass Example 2 3 / 3 pass 3 / 3 pass 3 / 3 pass 2 / 3 pass Example 3 3 / 3 pass 3 / 3 pass 3 / 3 pass 0 / 3 pass Example 4 3 / 3 pass 0 / 3 pass 0 / 3 pass 0 / 3 pass Example 5 3 / 3 pass 3 / 3 pass 0 / 3 pass 0 / 3 pass Example 6 3 / 3 pass 1 / 3 pass 0 / 3 pass 0 / 3 pass Example 7 2 / 3 pass 0 / 3 pass 0 / 3 pass 0 / 3 pass Comparative Example 1 0 / 3 pass 0 / 3 pass 0 / 3 pass 0 / 3 pass

[0075] As can be seen from Table 1, the results of the thermal box performance tests of the battery cores of Examples 1-3 are all better than those of the battery core of Comparative Example 1, indicating that in the present invention, the intermediate metal bending piece 31 of the heat conduction layer 3 is set in a wave shape, which can increase the specific surface area, and the first heat conduction material with a high heat conduction coefficient is filled at the wave crest. In the same length direction, at the same time, the metal bending piece 31 is in contact with the first heat conduction material with a high heat conduction coefficient, which can improve the heat dissipation ability of the aluminum-plastic film; in addition, the outer layer 1 mixed with the first heat conduction material with a high heat conduction coefficient in nylon helps to improve the problem of poor heat dissipation of the nylon layer of the existing aluminum-plastic film; adding metal or non-metal particles with high thermal conductivity to the first adhesive layer 2 can increase the heat transfer rate from the heat conduction layer 3 to the outer layer 1, improve the overall heat dissipation effect of the aluminum-plastic film, and improve the thermal box performance of the battery core. In addition, the results of the thermal box performance tests of the battery cores of Examples 5-7 are better than those of the battery core of Comparative Example 1, indicating that improving only one of the outer layer 1, the first adhesive layer 2, and the heat conduction layer 3 can also improve the overall heat dissipation effect of the aluminum-plastic film, but the best effect of the thermal box performance of the battery core cannot be achieved.

[0076] According to the disclosure and teaching of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the above specific embodiments, and any obvious improvements, substitutions, or variations made by those skilled in the art based on the present invention fall within the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. An aluminum-plastic film, characterized in that: It comprises an outer layer (1), a first adhesive layer (2), a heat-conducting layer (3), a second adhesive layer (5) and a sealing layer (4) which are stacked in sequence; The heat-conducting layer (3) comprises a metal bending sheet (31) and a first heat-conducting material, wherein the metal bending sheet (31) is arranged in the heat-conducting layer (3), and the first heat-conducting material fills a gap between the metal bending sheet (31) and the heat-conducting layer (3); The outer layer (1) is filled with a first heat-conducting material, and / or the first adhesive layer (2) is filled with a second heat-conducting material.

2. The aluminum-plastic film according to claim 1, characterized in that: The cross-sectional shape of the metal bending sheet (31) is wave-shaped, stepped, semicircular or stone pier-shaped.

3. An aluminum-plastic film as claimed in claim 2, characterized in that: A portion of the cross section of the metal bending sheet (31) is bent into an arc, and the radius of the arc is 0.5 μm to 1.5 μm.

4. An aluminum-plastic film according to any one of claims 1 to 3, characterized in that: The first thermally conductive material is glass fiber, carbon fiber, thermally conductive ceramic sheet or thermally conductive silica gel.

5. An aluminum-plastic film according to any one of claims 1 to 3, characterized in that: The second heat conductive material is metal particles or non-metal particles.

6. An aluminum-plastic film according to any one of claims 1 to 3, characterized in that: The second thermally conductive material is silicon particles, aluminum particles, magnesium particles or diamond particles.

7. An aluminum-plastic film according to any one of claims 1 to 3, characterized in that: The outer layer (1) is a nylon layer, the sealing layer (4) is a PP layer, and the metal bending sheet (31) is an aluminum sheet.

8. An aluminum-plastic film according to any one of claims 1 to 3, characterized in that: The metal bending sheet (31) extends along the length direction or the width direction of the heat conducting layer (3).

9. An aluminum-plastic film as claimed in claim 8, characterized in that: The projections of the metal bending sheet (31) and the heat conducting layer (3) in the thickness direction partially overlap.

10. A lithium-ion battery, characterized in that: The invention comprises the aluminum-plastic film according to any one of claims 1 to 9.

Images