Electrolyte-resistant heat-insulating al-plastic film for power battery, battery assembly and module structure

Abstract

This utility model discloses an electrolyte-resistant heat-insulating aluminum-plastic film for power batteries, a battery assembly, and a module structure, comprising a heat-sealing layer, an aluminum foil layer, and a nylon layer stacked sequentially from the inside out. The heat-sealing layer and the aluminum foil layer are connected by a first adhesive layer, and the aluminum foil layer and the nylon layer are connected by a second adhesive layer. A first corrosion-resistant layer is provided on the surface of the nylon layer away from the aluminum foil layer, and a first protrusion extending along a first direction is provided on the surface of the first corrosion-resistant layer away from the nylon layer, with adjacent first protrusions spaced apart. The first adhesive layer and / or the second adhesive layer consists of a unit adhesive outer layer and a heat-insulating core layer sandwiched between the unit adhesive outer layers. The first protrusions on the surface of the first corrosion-resistant layer increase the contact area of ​​the assembly, forming a stable concave-convex mating structure. The extension direction of the first protrusions is consistent with the electrolyte filling direction to prevent electrolyte retention. The adhesive layer is configured as a unit adhesive outer layer and a heat-insulating core layer to ensure high adhesion and heat insulation effect.

Description

Technical Field

[0001] This utility model relates to the field of aluminum-plastic film technology for batteries, and in particular to an electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries, battery components and module structures. Background Technology

[0002] A power battery consists of multiple lithium-ion battery cells. Lithium-ion battery manufacturing requires filling with electrolyte in a vacuum environment. This electrolyte can easily splash onto the nylon layer on the battery casing. Since nylon cannot withstand electrolyte corrosion, the nylon layer will turn white and blister after a certain period, leading to battery failure. Furthermore, lithium-ion battery cells have a large residual energy after thermal runaway. If one lithium-ion battery cell experiences thermal runaway, its heat will be continuously conducted to adjacent lithium-ion battery cells, causing heat diffusion throughout the entire power battery and resulting in damage to the entire battery.

[0003] Therefore, it is necessary to improve the heat insulation and electrolyte resistance properties of aluminum-plastic films in the existing technology. Utility Model Content

[0004] One of the objectives of this invention is to overcome the deficiencies in the existing technology and provide an electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries. The first protrusion on the surface of the first corrosion-resistant layer increases the surface contact area during power battery assembly, forming a concave-convex mating structure to improve connection stability. By adjusting the extension direction of the first protrusion to be consistent with the electrolyte filling direction, electrolyte retention on or around the first protrusion is prevented. The adhesive layer is configured as a unit adhesive outer layer and a heat-insulating adhesive core layer, ensuring not only high adhesion but also achieving a heat-insulating effect for the aluminum-plastic film.

[0005] To achieve the above technical effects, the technical solution of this utility model is as follows: an electrolyte-resistant heat-insulating aluminum-plastic film for power batteries, comprising a heat-sealing layer, an aluminum foil layer and a nylon layer stacked sequentially from the inside to the outside, wherein the heat-sealing layer and the aluminum foil layer are connected by a first adhesive layer, and the aluminum foil layer and the nylon layer are connected by a second adhesive layer;

[0006] A first corrosion-resistant layer is provided on the surface of the nylon layer away from the aluminum foil layer, and a first protrusion extending in a first direction is provided on the surface of the first corrosion-resistant layer away from the nylon layer, with adjacent first protrusions spaced apart.

[0007] The first adhesive layer and / or the second adhesive layer are composed of an outer unit adhesive layer and a heat-insulating core layer sandwiched between the outer unit adhesive layers.

[0008] A preferred technical solution is that the heat-sealing layer is a cast polypropylene layer.

[0009] The preferred technical solution is that the first corrosion-resistant layer is polyethylene terephthalate.

[0010] The preferred technical solution is that the first adhesive layer is a maleic anhydride modified polypropylene adhesive layer, and the second adhesive layer is a polyurethane adhesive layer.

[0011] The second objective of this utility model is to overcome the defects existing in the prior art and provide a battery assembly, including the above-mentioned electrolyte-resistant heat-insulating aluminum-plastic film for power batteries. The heat-sealing layers of the aluminum-plastic film are opposite to each other and surround a cell receiving groove. The cell receiving groove is provided with a cell. The cell receiving groove includes a filling port and a bottom end of the groove that are opposite to each other along the groove depth. The extension direction of the first protrusion is consistent with the groove depth direction.

[0012] The third objective of this utility model is to overcome the defects existing in the prior art and provide a module structure, including the above-mentioned battery assembly, and also including a heat insulation pad and a mounting bracket. The heat insulation pad includes an encapsulation layer and a phase change layer sandwiched between the encapsulation layers. A second corrosion-resistant layer is provided on the surface of the encapsulation layer away from the phase change layer. A second protrusion extending along a second direction is provided on the surface of the second corrosion-resistant layer away from the encapsulation layer. Adjacent second protrusions are spaced apart. The second direction is consistent with or at an angle to the first direction.

[0013] A preferred technical solution is that the battery components and heat insulation pads are interspersed and stacked on the mounting frame, with gaps between adjacent battery components and heat insulation pads.

[0014] A preferred technical solution is that the gap between adjacent battery components and heat insulation pads is filled with potting compound.

[0015] The preferred technical solution is that the potting compound is silicone or aerogel.

[0016] The advantages and beneficial effects of this utility model are as follows:

[0017] The electrolyte-resistant and heat-insulating aluminum-plastic film for this power battery has a reasonable structure. The first protrusion on the surface of the first corrosion-resistant layer increases the surface contact area when the power battery is assembled, forming a concave-convex structure to improve the connection stability. By adjusting the extension direction of the first protrusion to be consistent with the electrolyte filling direction, electrolyte is prevented from remaining on or around the first protrusion. The adhesive layer is set as a unit adhesive outer layer and a heat-insulating adhesive core layer, which not only ensures its high adhesion, but also enables the aluminum-plastic film to have a heat-insulating effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a cross-section of an electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries.

[0019] Figure 2 This is a schematic diagram of the battery assembly structure;

[0020] Figure 3This is a top view of part of the module structure;

[0021] Figure 4 This is a schematic diagram of the cross-section of the heat insulation pad.

[0022] In the diagram: 1. Aluminum-plastic film; 2. Heat insulation pad; 3. Battery assembly; 4. Mounting bracket; 11. Heat sealing layer; 12. Aluminum foil layer; 13. Nylon layer; 14. Nylon layer; 20. Phase change layer; 21. Encapsulation layer; 22. Second corrosion-resistant layer; 30. Cell receiving slot; 40. Encapsulating adhesive; 100. Unit adhesive outer layer; 101. Heat insulation core layer; 111. First adhesive layer; 112. Second adhesive layer; 141. First protrusion; 221. Second protrusion. Detailed Implementation

[0023] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0024] The terms "surface" and "end" refer to the normal operating state of the electrolyte-resistant heat-insulating aluminum-plastic film for power batteries. They are used only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0025] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0026] like Figures 1-4 As shown, the electrolyte-resistant heat-insulating aluminum-plastic film 1 for power batteries of this utility model includes a heat-sealing layer 11, an aluminum foil layer 12, and a nylon layer 13 stacked sequentially from the inside to the outside. The heat-sealing layer 11 and the aluminum foil layer 12 are connected by a first adhesive layer 111, and the aluminum foil layer 12 and the nylon layer 13 are connected by a second adhesive layer 112. A first corrosion-resistant layer 14 is provided on the surface of the nylon layer 13 away from the aluminum foil layer 12. A first protrusion 141 extending in a first direction is provided on the surface of the first corrosion-resistant layer 14 away from the nylon layer 13. Adjacent first protrusions 141 are spaced apart. The first adhesive layer 111 and / or the second adhesive layer 112 are composed of a unit adhesive outer layer 100 and a heat-insulating adhesive core layer 101 sandwiched between the unit adhesive outer layers 100.

[0027] The first protrusion 141 on the surface of the first corrosion-resistant layer 14 increases the surface contact area when assembling the power battery, forming a concave-convex structure to improve connection stability. By adjusting the extension direction of the first protrusion 141 to be consistent with the electrolyte filling direction, electrolyte is prevented from remaining on or around the first protrusion 141. The adhesive layer is set as an outer layer of unit adhesive and a heat-insulating core layer, which not only ensures its high adhesion, but also enables the aluminum-plastic film to have a heat insulation effect.

[0028] The first corrosion-resistant layer 14 has a minimum thickness of 4-12 μm, the nylon layer 13 has a thickness of 10-30 μm, the first adhesive layer 111 and the second adhesive layer 112 have a thickness of 3-6 μm, the aluminum foil layer 12 has a thickness of 20-60 μm, and the heat-sealing layer 11 has a thickness of 20-80 μm. Preferably, the first corrosion-resistant layer 14 has a minimum thickness of 6 μm, the nylon layer 13 has a thickness of 15 μm, the first adhesive layer 111 and the second adhesive layer 112 have a thickness of 4 μm, the aluminum foil layer 12 has a thickness of 40 μm, and the heat-sealing layer 11 has a thickness of 40 μm.

[0029] The heat-sealing layer 11 is a maleic anhydride-modified polypropylene layer. The advantages of this material selection include: the anhydride groups on the molecular chain of maleic anhydride-modified polypropylene can form chemical bonds with many polar materials, significantly improving adhesion strength, which is crucial for ensuring a strong connection between the tabs and the plastic film; better thermal stability compared to unmodified polypropylene, allowing it to be processed at high temperatures without easily decomposing or losing its physical properties, which is critical for ensuring the effectiveness and reliability of the heat-sealing step in battery manufacturing; good compatibility with other materials, including different types of plastics and metals, providing greater flexibility in the design of multilayer composite materials; and higher resistance to various chemicals, meaning that composites made from this material are more durable when facing electrolytes or other potentially harmful environmental factors.

[0030] The first corrosion-resistant layer 14 is polyethylene terephthalate (PET). While the nylon layer (PA polyamide) as the outer layer possesses good mechanical properties and barrier properties, its resistance to chemical corrosion (especially to strong acids, strong alkalis, or certain organic solvents) is relatively weak. PET exhibits good resistance to most acids, alkalis, salts, and organic solvents (such as ethanol and acetone), effectively protecting the aluminum foil layer and nylon layer from corrosive media and extending the service life of the aluminum-plastic film. PET has high tensile strength and puncture resistance, enhancing the overall structural stability of the aluminum-plastic film and preventing damage caused by external forces (such as friction and compression). In low-humidity environments, PET's barrier properties against water vapor and oxygen are superior to nylon, reducing the risk of oxidation or hydrolysis of the aluminum foil layer, which is crucial for water- and oxygen-sensitive applications such as lithium batteries. PET is easy to laminate with the nylon layer and has a lower cost, making it suitable for large-scale industrial applications.

[0031] The first adhesive layer 111 needs to be resistant to electrolyte. It needs to be stamped into an aluminum-plastic film to form a shell for packaging electrolyte. The aluminum-plastic film needs to have good flexibility and resistance to bending fatigue. Therefore, the first adhesive layer 111 is a maleic anhydride modified polypropylene adhesive layer, and the second adhesive layer 112 is a polyurethane adhesive layer.

[0032] like Figure 2 As shown, the battery assembly 3 includes the aforementioned electrolyte-resistant heat-insulating aluminum-plastic film 1 for power batteries. The heat-sealing layers 11 of the aluminum-plastic film 1 are arranged opposite each other to form a cell receiving groove 30. The cell receiving groove 30 is provided with a cell (not shown). The cell receiving groove 30 includes a filling port (not marked) and a bottom end (not marked) that are opposite each other along the groove depth. The extension direction of the first protrusion 141 is consistent with the groove depth direction. This ensures that the extension direction of the first protrusion 141 is consistent with the electrolyte filling direction, preventing electrolyte from accumulating on or around the first protrusion 141, and also ensuring that the first corrosion-resistant layer 14 is easy to clean and keeps its surface clean.

[0033] like Figure 3 As shown, the module structure includes the aforementioned battery assembly 3, as well as a heat insulation pad 2 and a mounting bracket 4. The heat insulation pad 2 includes an encapsulation layer 21 and a phase change layer 20 sandwiched between the encapsulation layers 21. A second corrosion-resistant layer 22 is provided on the surface of the encapsulation layer 21 away from the phase change layer 20. A second protrusion 221 extending along a second direction is provided on the surface of the second corrosion-resistant layer 22 away from the encapsulation layer 21. Adjacent second protrusions 221 are spaced apart, and the second direction is consistent with or at an angle to the first direction. Since the heat insulation pad 2 is used to prevent thermal runaway of adjacent battery cells, which could lead to damage to the entire battery due to heat diffusion, the strong connection between the heat insulation pad 2 and the battery assembly 3 is also crucial.

[0034] To achieve the heat insulation effect, the battery assembly 3 and the heat insulation pad 2 are interspersed and stacked on the mounting bracket 4, with gaps between adjacent battery assemblies 3 and heat insulation pads 2. Furthermore, the gaps between adjacent battery assemblies 3 and heat insulation pads 2 are filled with potting compound 40; the potting compound 40 is silicone or aerogel. Both adjacent battery assemblies 3 and heat insulation pads 2 are in contact with the potting compound 40, improving the connection strength.

[0035] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A heat-insulating aluminum-plastic film for power batteries with electrolyte resistance, comprising a heat-sealing layer, an aluminum foil layer and a nylon layer stacked sequentially from the inside to the outside, wherein the heat-sealing layer and the aluminum foil layer are connected by a first adhesive layer and the aluminum foil layer and the nylon layer are connected by a second adhesive layer; Its features are, A first corrosion-resistant layer is provided on the surface of the nylon layer away from the aluminum foil layer, and a first protrusion extending in a first direction is provided on the surface of the first corrosion-resistant layer away from the nylon layer, with adjacent first protrusions spaced apart. The first adhesive layer and / or the second adhesive layer are composed of an outer unit adhesive layer and a heat-insulating core layer sandwiched between the outer unit adhesive layers.

2. The electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries according to claim 1, characterized in that, The heat-sealing layer is a cast polypropylene layer.

3. The electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries according to claim 1, characterized in that, The first corrosion-resistant layer is polyethylene terephthalate.

4. The electrolyte-resistant and heat-insulating aluminum-plastic film for power batteries according to claim 1, characterized in that, The first adhesive layer is a maleic anhydride-modified polypropylene adhesive layer, and the second adhesive layer is a polyurethane adhesive layer.

5. A battery assembly, characterized in that, The invention includes the electrolyte-resistant heat-insulating aluminum-plastic film for power batteries as described in any one of claims 1 to 4, wherein the heat-sealing layers of the aluminum-plastic film are opposite to each other and surround a cell receiving groove, the cell receiving groove is provided with a cell, and the cell receiving groove includes a filling port and a bottom end of the groove that are opposite to each other along the groove depth, and the extension direction of the first protrusion is consistent with the groove depth direction.

6. A module structure, characterized in that, The battery assembly of claim 5 further includes a heat insulation pad and a mounting bracket. The heat insulation pad includes an encapsulation layer and a phase change layer sandwiched between the encapsulation layers. A second corrosion-resistant layer is provided on the surface of the encapsulation layer away from the phase change layer. A second protrusion extending in a second direction is provided on the surface of the second corrosion-resistant layer away from the encapsulation layer. Adjacent second protrusions are spaced apart. The second direction is consistent with or at an angle to the first direction.

7. The module structure according to claim 6, characterized in that, The battery components and heat insulation pads are interspersed and stacked on the mounting frame, with gaps between adjacent battery components and heat insulation pads.

8. The module structure according to claim 7, characterized in that, The gaps between adjacent battery components and heat insulation pads are filled with potting compound.

9. The module structure according to claim 8, characterized in that, The potting compound is silicone or aerogel.

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