CN213150884U

CN213150884U - Aluminum-plastic film structure and lithium ion battery

Info

Publication number: CN213150884U
Application number: CN202021386873.8U
Authority: CN
Inventors: 向萍
Original assignee: Shanghai Cenat New Energy Co Ltd
Current assignee: Shanghai Cenat New Energy Co Ltd
Priority date: 2020-07-14
Filing date: 2020-07-14
Publication date: 2021-05-07
Anticipated expiration: 2030-07-14

Abstract

The utility model is suitable for a lithium ion battery field provides an aluminum-plastic film structure and lithium ion battery. Wherein plastic-aluminum membrane structure, including nylon layer, aluminium lamination and the CPP layer of range upon range of setting, plastic-aluminum membrane structure is still including locating the first insulating layer between aluminium lamination and the CPP layer. The utility model provides an aluminum-plastic membrane structure can improve the high temperature resistant ability of aluminum-plastic membrane structure, hinders the chain thermal runaway phenomenon that high temperature external radiation probably produced, hinders high temperature internal radiation simultaneously and makes electric core be in relatively stable operating temperature.

Description

Aluminum-plastic film structure and lithium ion battery

Technical Field

The utility model belongs to the lithium ion battery field especially relates to an aluminum-plastic film structure and lithium ion battery.

Background

Because the requirement of the current market on the energy density of the battery core is higher and higher, in order to pursue high energy density, the material of the positive electrode is selected to be a material with higher capacity, but the stability of the material is poor, the surface of the material is easy to break and decompose in the charging and discharging process to release oxygen, so that the temperature of the battery core is continuously increased, finally, the internal short circuit occurs in the battery core, and the temperature is rapidly increased to cause thermal runaway. Because heat conduction, the inside electricity core that has generated thermal runaway transmits the heat to adjacent electric core through electric core extranal packing plastic-aluminum membrane, and makes adjacent electric core temperature climb, finally triggers the chain thermal runaway reaction of battery module. Therefore, it is important to block the temperature transmission between the battery cells and improve the thermal insulation of the aluminum-plastic film. In the prior art, an aluminum-plastic film used for a battery core is high in heat conductivity coefficient, the aluminum-plastic film usually comprises a nylon layer, an aluminum layer and a CPP layer, the CPP layer is made of a polypropylene material, the melting point is 170 ℃, and the high-temperature resistance is poor. Once the internal temperature of the battery core exceeds the melting point of the CPP layer, the CPP layer is melted and fails, reactants inside the battery core and the aluminum layer are subjected to chemical reaction, and the aluminum-plastic film fails.

In the existing design, a heat insulation plate is added between each electric core to reduce the temperature transfer between the electric cores under the condition of thermal runaway of the electric cores, and the mode has high requirement on the heat insulation plate material and poor heat insulation effect; a liquid cooling system is arranged in the battery pack to cool each battery core, but the method can additionally increase the weight of the battery pack and reduce the energy conversion rate of the battery core.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome above-mentioned prior art not enough, provide an aluminum-plastic membrane structure and lithium ion battery, it aims at another kind and solves the interior electric core of battery package and takes place chain thermal runaway's scheme.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

in a first aspect, the aluminum-plastic film structure comprises a nylon layer, an aluminum layer and a CPP layer which are arranged in a stacked mode, and further comprises a first heat insulation layer arranged between the aluminum layer and the CPP layer.

Through adopting above-mentioned technical scheme, through add first insulating layer between aluminium lamination and CPP layer, reach thermal-insulated and the effect of protection aluminium lamination, improve the high temperature resistance ability of plastic-aluminum membrane structure, hinder the chain thermal runaway phenomenon that high temperature external radiation probably produced, hinder high temperature internal radiation simultaneously and make electric core be in relatively stable operating temperature.

Optionally, the first thermal insulation layer is made of mica.

By adopting the technical scheme, a better heat insulation effect is obtained.

Optionally, the thickness of the first thermal insulation layer is 10-30 μm.

By adopting the technical scheme, the requirement of the high-temperature resistance of the aluminum plastic film is met, and the manufacturing cost of the first heat insulation layer is reduced.

Optionally, the aluminum layer has a thickness of 30-40 μm.

By adopting the technical scheme, the requirements of water resistance and plasticity of the aluminum-plastic film structure can be met.

Optionally, the nylon layer has a thickness of 25-30 μm.

By adopting the technical scheme, the material cost is reduced on the basis of meeting the performance requirement of the nylon layer.

Optionally, the CPP layer has a thickness of 30-40 μm.

By adopting the technical scheme, the packaging quality can be ensured and the material cost is reduced.

Optionally, the aluminum layer and the first thermal insulation layer, and the first thermal insulation layer and the CPP layer are all adhesively connected by a first adhesive layer.

By adopting the technical scheme, the cutting performance, the short-circuit prevention performance and the appearance performance of the aluminum-plastic film structure are improved.

Optionally, the aluminum-plastic film structure further includes a second thermal insulation layer disposed between the nylon layer and the aluminum layer, and the second thermal insulation layer is made of mica.

By adopting the technical scheme, the high-temperature resistance and the heat insulation effect of the aluminum plastic film structure are further improved, the chain thermal runaway phenomenon possibly generated by high-temperature outward radiation is prevented, and meanwhile, the high-temperature inward radiation is prevented to enable the battery cell to be at a relatively stable working temperature.

Optionally, the nylon layer and the second heat insulation layer, and the second heat insulation layer and the aluminum layer are bonded and connected through a second adhesion layer.

In a second aspect, a lithium ion battery is provided, which includes the aluminum plastic film structure as described above.

By adopting the technical scheme, the high temperature resistance and the insulating capability of the aluminum-plastic film structure are improved, the interlocking thermal runaway phenomenon possibly generated by high-temperature outward radiation is prevented, and meanwhile, the high-temperature inward radiation is prevented to enable the battery cell to be at a relatively stable working temperature.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a first schematic view of an aluminum-plastic film structure provided in an embodiment of the present application;

fig. 2 is a second schematic diagram of an aluminum plastic film structure provided in the embodiment of the present application.

Wherein, in the figures, the respective reference numerals:

1. a nylon layer; 2. an aluminum layer; 3. a CPP layer; 4. a first insulating layer; 51. a first adhesive layer; 52. a second adhesive layer; 6. a second insulating layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

Referring to fig. 1 and fig. 2, an embodiment of the present application provides an aluminum-plastic film structure and a lithium ion battery using the aluminum-plastic film structure.

The plastic-aluminum membrane structure comprises a nylon layer 1, an aluminum layer 2, a CPP layer 3 and a first heat insulation layer 4, wherein the nylon layer 1, the aluminum layer 2 and the CPP layer 3 are arranged in a stacking mode, and the first heat insulation layer 4 is arranged between the aluminum layer 2 and the CPP layer 3.

The first insulating layer 4 is made of mica. The mica has good heat resistance, the natural mica can work for a long time at the high temperature of 800 ℃, the synthetic mica can resist the high temperature of 1200 ℃, and the synthetic mica has good heat insulation effect. Mica is an aluminosilicate amphoteric substance, and has the advantages of acid and alkali resistance, corrosion resistance, good chemical stability and good corona resistance.

The first thermal insulation layer 4 can also be made of inorganic thermal insulation material such as aerogel material, aerogel felt material, etc. to be suitable for high temperature environment and provide thermal insulation function.

When the cell wrapped by the aluminum-plastic film added with the first heat insulation layer 4 loses efficacy due to internal thermal runaway of the CPP layer 3, the shape of the cell is maintained at high temperature due to the good heat resistance of the first heat insulation layer 4, so that the electrolyte is prevented from contacting with the aluminum layer 2 to react, and the aluminum layer 2 is protected. It should be noted that the first thermal insulating layer 4 contacts the electrolyte but does not chemically react with the electrolyte in the case of welding of the CPP layer 3, so as to ensure the structural integrity of the first thermal insulating layer 4 and protect the aluminum layer 2. In addition, the addition of the first heat insulation layer 4 can protect the aluminum layer 2 during CPP packaging, and the risk of excessive melting and electric leakage during heat sealing of the CPP layer 3 caused by improper process treatment in the battery cell packaging process is reduced.

First insulating layer 4 has good thermal-insulated effect and can reduce the inside outside transmission of heat of electric core for adjacent electric core can normally work and not receive the temperature influence, and fundamentally avoids the chain thermal runaway problem between the electric core, and strives for the time for BMS system detects unusual electric core in the battery package, improves battery package factor of safety. In addition, the first heat insulation layer 4 has a good heat insulation effect, and can also reduce the inward conduction of the external environment temperature of the battery cell, so that the battery cell can still normally operate at high temperature.

By last, the plastic-aluminum membrane that this embodiment provided combines and lithium ion battery through add first insulating layer 4 between aluminium lamination 2 and CPP layer 3, reaches thermal-insulated and the effect of protection aluminium lamination 2, improves the high temperature resistance ability of plastic-aluminum membrane structure, hinders the chain thermal runaway phenomenon that high temperature external radiation probably produced, hinders high temperature internal radiation simultaneously and makes electric core be in relatively stable operating temperature.

Mica has a unique crystal structure, which makes it have a group of extremely complete basal cleavage, and can be peeled, sized, cut to a desired thickness, theoretically, a flake thickness of 0.001 μm. In addition, the mica has good dielectric strength and mechanical property, and does not generate layer, crack and deformation when being processed and punched. The thickness of the first heat-insulating layer 4 is preferably 10-30 μm, which can meet the requirement of the aluminum plastic film on high temperature resistance and reduce the manufacturing cost of the first heat-insulating layer 4. The thickness of the first insulating layer 4 may be 10 μm, 11 μm, 15 μm, 16 μm, 18 μm, 19 μm, 20 μm, 22.5 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 30 μm, etc.

The aluminum layer 2 has the main function of preventing moisture from entering the aluminum plastic film structure, and the metal aluminum and oxygen in the air can generate oxidation reaction at room temperature to generate an aluminum oxide film layer on the surface of the outer layer, so that water vapor is prevented from permeating to protect the interior of the battery cell. At the same time, the aluminium layer 2 provides the required plasticity when the aluminium-plastic film structure is crated. The thickness of the aluminum layer 2 is preferably 30-40 μm, and the waterproof and plasticity requirements of the aluminum-plastic film structure can be met. The aluminum layer 2 may have a thickness of 30 μm, 31 μm, 32 μm, 33 μm, 34.5 μm, 35 μm, 36 μm, 37.5 μm, 38 μm, 39 μm, 40 μm, or the like.

The nylon layer 1 is used for protecting the aluminum layer 2 from being scratched, can be continuously operated in the processing process without damaging the appearance, and reduces the influence of impact shock generated by falling of the lithium ion battery on the inside of the battery cell in the use process of the lithium ion battery. The thickness of the nylon layer 1 is preferably 25-30 μm, so that the material cost is reduced on the basis of meeting the performance requirement. The thickness of the nylon layer 1 may be 25 μm, 25.5 μm, 26 μm, 26.8 μm, 27 μm, 28 μm, 29 μm, 30 μm, or the like.

The CPP (polypropylene) layer 3 is used for bonding with the tab. In this scheme, the adding of first insulating layer 4 can protect aluminium lamination 2 when CPP encapsulates, reduces the risk of excessive melt electric leakage when the improper CPP layer 3 heat-seal that causes because of technology handles among the electric core packaging process, consequently, reduces to 30-40 mu m under the condition that encapsulation quality can be guaranteed to CPP layer 3 thickness, and reduces the material cost. The CPP layer 3 may have a thickness of 30 μm, 31 μm, 32 μm, 33 μm, 34.5 μm, 35 μm, 36 μm, 37.8 μm, 38.5 μm, 39 μm, 40 μm, etc.

In another embodiment of the present application, referring to fig. 1, the aluminum layer 2 and the first thermal insulation layer 4, and the first thermal insulation layer 4 and the CPP layer 3 are adhesively connected by first adhesive layers 51, and each first adhesive layer 51 is made of an adhesive. The aluminum layer 2, the first thermal insulation layer 4 and the CPP layer 3 are bonded through the first adhesion layer 51 and then directly pressed. Namely, the aluminum-plastic film structure is prepared by a dry method, and compared with a heat seal preparation method, the aluminum-plastic film structure prepared by the dry method has good cutting performance, short circuit prevention performance and appearance performance.

In the structure shown in fig. 1, the nylon layer 1 and the aluminum layer 2 are adhesively bonded to each other by the first adhesive layer 51.

In this embodiment, each first adhesion layer 51 is made of the same adhesive, so as to reduce the production cost. In other embodiments, each first adhesive layer 51 may be selected from different adhesives according to the materials to be adhered, and is not limited herein.

The skilled person can also use MPP (modified polypropylene) to connect the aluminum layer 2, the first thermal insulation layer 4 and the CPP layer 3, and then hot press them by heating and pressing, i.e. a hot press preparation method is used. And are not intended to be limited solely thereto.

In another embodiment of the present application, referring to fig. 2, the aluminum-plastic film structure further includes a second thermal insulation layer 6 disposed between the nylon layer 1 and the aluminum layer 2, and the second thermal insulation layer 6 is made of mica. The arrangement of the second heat insulation layer 6 further improves the high temperature resistance and the heat insulation effect of the aluminum plastic film structure, and blocks the chain thermal runaway phenomenon possibly generated by high temperature outward radiation, and simultaneously blocks the high temperature inward radiation to enable the battery cell to be at a relatively stable working temperature.

The nylon layer 1, the second thermal insulation layer 6 and the aluminum layer 2 are connected by a second adhesive layer 52. Each of the second adhesive layers 52 is made of an adhesive. Preferably, the first adhesive layer 51 and the second adhesive layer 52 are the same material and differ only in position.

In combination with the figure, the nylon layer 1, the second thermal insulation layer 6 and the aluminum layer 2 are all bonded and connected through the second adhesion layer 52, the aluminum layer 2, the first thermal insulation layer 4 and the CPP layer 3 are all bonded and connected through the first adhesion layer 51, and after adhesion, the aluminum-plastic film structure which is stably connected is formed through direct pressing.

The preparation method comprises the following steps:

preparing a CPP layer 3 with the thickness of 30-40 microns, a mica sheet with the thickness of 10-30 microns, an aluminum layer 2 with the thickness of 30-40 microns and a nylon layer 1 with the thickness of 25-30 microns, adhering the layers by using an adhesive with the thickness of 2-3 microns, and then integrally pressing to form the aluminum-plastic film structure shown in the figure 1 or the figure 2.

The battery core is formed by respectively assembling a positive plate of an aluminum foil with the thickness of 12-15 mu m and a positive active material, a conductive agent and a binder, a negative plate of a copper foil with the thickness of 6-8 mu m and a negative active material, a conductive agent and a binder, and a diaphragm with the thickness of 16-25 mu m in a zigzag lamination manner, the battery core is placed into a punched aluminum-plastic film structure, electrolyte is injected, and then the battery core is sealed and assembled at the sealing temperature of 150 ℃ and 170 ℃ on a full-automatic heat sealing machine.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modification, equivalent replacement or improvement made within the spirit and principle of the present invention should be included in the present invention.

Claims

1. An aluminum-plastic film structure comprises a nylon layer, an aluminum layer and a CPP layer which are arranged in a laminated manner, and is characterized by further comprising a first heat insulation layer arranged between the aluminum layer and the CPP layer; the first heat insulation layer is made of mica.

2. The aluminum-plastic film structure of claim 1, wherein the first thermal barrier layer has a thickness of 10-30 μm.

3. The aluminum-plastic film structure of claim 1, wherein the aluminum layer has a thickness of 30 to 40 μm.

4. The aluminum-plastic film structure of claim 1, wherein the nylon layer has a thickness of 25 to 30 μm.

5. The aluminum-plastic film structure of claim 1, wherein the CPP layer has a thickness of 30-40 μ ι η.

6. The aluminum-plastic film structure of any one of claims 1 to 5, wherein the first thermal insulation layer and the aluminum layer, the first thermal insulation layer and the CPP layer are adhesively connected by a first adhesive layer.

7. The aluminum-plastic film structure of any of claims 1 to 5, further comprising a second insulating layer disposed between the nylon layer and the aluminum layer.

8. The aluminum-plastic film structure of claim 7, wherein the nylon layer and the second thermal insulation layer, and the second thermal insulation layer and the aluminum layer are bonded together by a second adhesive layer.

9. A lithium ion battery comprising the aluminum plastic film structure of any one of claims 1 to 8.