High-safety outer coating for preventing lithium battery combustion and its production method

Abstract

This invention discloses a high-safety outer coating for preventing lithium battery combustion and its production method, belonging to the field of lithium battery outer coatings. The high-safety outer coating for preventing lithium battery combustion includes a first bonding layer, a metal layer, and a nylon layer arranged sequentially from bottom to top. The metal layer is made of aluminum. The flame-retardant gas is composed of the following raw materials in parts by weight: 10-20 parts inert gas, 10-20 parts chemical gas, and 10-20 parts carbon dioxide. The flame-retardant material is composed of the following raw materials in parts by weight: 5-10 parts dry powder and 5-10 parts metal powder. This invention solves the problem that existing battery outer coatings suffer from reduced safety and weak flame-retardant ability in actual use due to short circuits caused by impacts, which generate continuous high temperatures and eventually lead to combustion. By filling the protruding grooves with gas and particles, the gas and particles are ejected when the battery is impacted and punctured, thus limiting the combustion of the flame.

Description

Technical Field

[0001] This invention relates to the field of lithium battery outer coatings, specifically to a high-safety outer coating that prevents lithium battery combustion and its production method. Background Technology

[0002] The outer coating of a lithium battery is a protective film that covers the surface of the lithium battery. It is used to protect the battery from the influence of the external environment, such as moisture, dust, and dirt. It is usually composed of one or more layers of materials and has functions such as waterproofing, dustproofing, and scratch resistance to ensure the safety and stability of the lithium battery.

[0003] Chinese Patent Publication No. CN215600444U discloses a novel outer coating for batteries, comprising an outer coating body, the outer coating body including parallel processed first and second vertical sides; the upper and lower ends of the first and second vertical sides are connected by first and second irregular sides respectively; the first irregular side includes a connected first oblique side, a first flat side and a second oblique side. The novel outer coating for batteries can adapt to specific processing needs, increase the size of the coating in the middle of the battery and prevent deformation.

[0004] In actual use, the battery outer film of the aforementioned patent can only wrap and protect the outside of the battery. However, if an impact causes a short circuit in the lithium battery, it will continuously generate high temperatures. After the sustained high temperature, the battery will burn. The battery outer film cannot limit the combustion of the flame, which reduces the safety of the battery in actual use and weakens its flame retardant ability. Summary of the Invention

[0005] The purpose of this invention is to provide a high-safety outer coating for preventing lithium battery combustion and a method for producing the same. By filling the protruding groove with gas and particles, the particles and gas are ejected when the battery is impacted and punctured, thus limiting the combustion of the flame and solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-safety outer coating to prevent lithium battery combustion, comprising a first bonding layer, a metal layer, and a nylon layer arranged sequentially from bottom to top. The metal layer is made of aluminum. A second protective layer is provided at the upper end of the nylon layer. A first protective layer is provided at the upper end of the second protective layer. A flame-retardant gas is arranged in an array inside the first protective layer facing the second protective layer. A protruding groove is provided on the outside of the flame-retardant gas. Both sides of the inside of the flame-retardant gas are filled with flame-retardant material. The flame-retardant gas is composed of the following raw materials in parts by weight: 10-20 parts of inert gas, 10-20 parts of chemical gas, and 10-20 parts of carbon dioxide. The flame-retardant material is composed of the following raw materials in parts by weight: 5-10 parts of dry powder and 5-10 parts of metal powder.

[0007] Preferably, both the first and second protective layers are composed of a mixture of polyester, polyimide, and polyethylene, wherein the mass ratio of polyester, polyimide, and polyethylene is 1:1:1.

[0008] Preferably, the protruding groove and the first protective layer are an integral structure, the horizontal height of the protruding groove is no more than two millimeters, a pressing groove is provided in the middle of the protruding groove, and the flame-retardant material is located on both sides of the pressing groove.

[0009] Preferably, the inert gas is nitrogen.

[0010] Preferably, the chemical gas is xenon.

[0011] Preferably, the dry powder is an inorganic salt.

[0012] Preferably, the metal powder is sodium chloride.

[0013] Preferably, a second bonding layer is applied to the lower end of the pressing groove position on the inner wall of the protruding groove, and both the first bonding layer and the second bonding layer are made of polypropylene.

[0014] Preferably, the heating temperature of the second bonding layer pressing position is 100°C, and the pressing device continuously presses the pressing groove and makes the second bonding layer adhere to the upper end of the second protective layer for 5-7 minutes.

[0015] A method for producing a high-safety outer coating to prevent lithium battery combustion includes the following steps:

[0016] Step 1: Cut the metal layer and nylon layer, and then use adhesive to bond and combine the metal layer and nylon layer together. The combination serves as the support for the entire lithium battery outer film. The metal layer increases the strength of the lithium battery outer film, and the nylon layer can block the penetration of water vapor, thus protecting the inside of the battery cell.

[0017] Step 2: Mix and stir polyester, polyimide and polyethylene. Wash and dry the mixture of polyester, polyimide and polyethylene. After drying, pour the mixture into a high-temperature melt extruder, melt it into a colloid and extrude it.

[0018] Step 3: Extrusion and pressing to form a sheet. After cooling, the sheet is fed into a longitudinal stretching machine, which stretches the sheet longitudinally.

[0019] Step 4: Divide the sheet into two equal parts. One part is set aside as the second protective layer and is used as the first protective layer by impact to form a groove. Heat treat both parts of the sheet.

[0020] Step 5: Cool the heat-treated film to room temperature to eliminate the heat and stress generated during the heat treatment process;

[0021] Step 6: Lay the second protective layer, which was not impacted in Step 4, on the top of the nylon layer and adhere it to the top of the nylon layer. Lay the material, which is the second protective layer, the nylon layer and the metal layer as a whole, inside the sealed device. Pour the flame retardant material array onto the top of the second protective layer.

[0022] Step 7: Move the first protective layer, which was dented and protruded by the impact in Step 4, toward the second protective layer, aligning the dented position with the second protective layer, and simultaneously aligning it with the flame-retardant material placed on the upper end of the second protective layer in Step 6.

[0023] Step 8: Fill the sealing device with flame-retardant gas. The flame-retardant gas will cause the protruding groove to expand, so as to avoid affecting the adhesion of the first protective layer and the second protective layer. Apply glue before the first protective layer and the second protective layer come into contact. Apply the second bonding layer at the middle position of the lower end of the protruding groove so that the first protective layer and the second protective layer are bonded and combined in the expanded state of the protruding groove.

[0024] Step 9: The stamping device extrudes the protruding groove surface at the position corresponding to the second bonding layer, so that the second bonding layer adheres to the second protective layer. The stamping device generates high temperature at the contact position with the first protective layer, which melts the second bonding layer and causes the protruding groove to stick to the second protective layer.

[0025] Step 10: A first adhesive layer is applied to the lower end of the metal layer. When it is subsequently attached to the battery surface, the first adhesive layer adheres to the battery and is heated. After the first adhesive layer melts, the structure of the first protective layer, the second protective layer, the nylon layer and the metal layer as a whole is fixed to the battery surface.

[0026] Step 11: Test the various performance indicators of the lithium battery separator. The slitting and packaging process mainly involves slitting and packaging the wound film according to certain size requirements.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention involves filling the space between the first and second protective layers with flame-retardant gas and flame-retardant material simultaneously. The protruding grooves on the outside buffer against impacts. When a sharp object punctures the battery, causing a short circuit and combustion, the sharp object will also puncture the protruding grooves containing the flame-retardant gas and material. The punctured grooves release the gas, carrying the flame-retardant material with them. The released gas envelops and suppresses the puncture site, preventing oxygen from entering. The flame-retardant gas actively retards the flame, and the released flame-retardant material covers the puncture site, further limiting the flame's combustion. The filling of flame-retardant gas and material improves battery safety during use, preventing continuous combustion after impact. Attached Figure Description

[0029] Figure 1 This is a perspective view of the overall external structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the outer membrane structure of the present invention;

[0031] Figure 3 For the present invention Figure 2 Enlarged view of a portion of region A in the middle;

[0032] Figure 4 This is a schematic diagram showing the positional relationship of the flame-retardant gases in this invention;

[0033] Figure 5 This is a schematic diagram showing the trajectory of the flame-retardant gas and flame-retardant material ejected after the protruding groove of the present invention is punctured.

[0034] In the diagram: 1. First protective layer; 2. Second protective layer; 3. Nylon layer; 4. Metal layer; 5. First bonding layer; 6. Protruding groove; 7. Pressing groove; 8. Second bonding layer; 9. Flame-retardant gas; 10. Flame-retardant material. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1:

[0037] To address the problem that in existing technologies, battery outer films can only protect the outside of the battery during actual use, while collisions can cause short circuits in lithium batteries, generating sustained high temperatures that can lead to combustion. Since the outer film cannot contain the flame, this reduces battery safety and weakens its flame-retardant capabilities during actual use. This embodiment provides the following technical solution:

[0038] The high-safety outer coating for preventing lithium battery combustion includes, from bottom to top, a first bonding layer 5, a metal layer 4, and a nylon layer 3, as shown below. Figure 1 and Figure 2 As shown, the first bonding layer 5 is made of polypropylene. Polypropylene melts at temperatures above 100 degrees Celsius and has adhesive properties. The battery's heat sealing mainly relies on the first bonding layer 5 melting and bonding together under the heating of the end cap. Then, the end cap is removed, and cooling causes it to solidify and bond. Heating the first bonding layer 5 allows the outer film to adhere to the battery surface. The metal layer 4 is made of aluminum. The purpose of laying the metal layer 4 is to prevent water penetration. The metal layer 4 blocks the penetration of moisture. At room temperature, the metal layer 4 reacts with oxygen in the air to form a dense oxide film, preventing moisture penetration and protecting the inside of the battery cell. Additionally, the metal layer 4 also improves the quality of the battery during molding. The nylon layer 3 provides plasticity to withstand impacts and improves the protection of the internal battery. A second protective layer 2 is provided on the upper end of the nylon layer 3, and a first protective layer 1 is provided on the upper end of the second protective layer 2. The first protective layer 1 and the second protective layer 2 are the outer protective film of the separator or battery packaging. The first protective layer 1 and the second protective layer 2 have good chemical stability, mechanical strength and electrical insulation properties to meet the battery's usage requirements in various environments. Flame-retardant gas 9 is arranged in an array inside the first protective layer 1 facing the second protective layer 2. Flame-retardant material 10 is filled on both sides inside the flame-retardant gas 9. The filling of flame-retardant material 10 allows the flame-retardant material 10 to directly contact the burning position when the battery is impacted, and directly retard the flame.

[0039] In this embodiment, both the first protective layer 1 and the second protective layer 2 are composed of polyester, polyimide and polyethylene. When the first protective layer 1 and the second protective layer 2 are combined, the flame-retardant gas 9 and the flame-retardant material 10 can be wrapped between the first protective layer 1 and the second protective layer 2, so that the protruding groove 6 is the flame-retardant point of the battery outer film, actively limiting the combustion of the flame and improving the safety of the battery during use. The mass ratio of polyester, polyimide and polyethylene is 1:1:1.

[0040] In this embodiment, the flame-retardant gas 9 is composed of the following parts by weight of raw materials: 10 parts of inert gas, 10 parts of chemical gas and 10 parts of carbon dioxide. The flame-retardant material 10 is composed of the following parts by weight of raw materials: 5 parts of dry powder and 5 parts of metal powder. After the external foreign object punctures the protrusion groove 6, the gas and powder reserved inside the protrusion groove 6 will be squeezed out and directly contact the battery ignition position, accurately limiting the flame at that position and restricting the combustion of the flame.

[0041] In this embodiment, the horizontal height of the protruding groove 6 is no more than two millimeters. Limiting the protruding height of the groove 6 facilitates the wrapping or flat storage of the outer film. Limiting the horizontal height also prevents the battery from becoming too thick after being wrapped in the outer film, thus avoiding the protruding groove 6 affecting the actual use and installation of the battery. Figure 3 , Figure 4 and Figure 5 As shown, a pressing groove 7 is provided in the middle of the protruding groove 6. The lower end of the pressing groove 7 on the inner wall of the protruding groove 6 is coated with a second adhesive layer 8. The external pressing heating structure can make the second adhesive layer 8 on the inner wall of the first protective layer 1 adhere to the upper end of the second protective layer 2 by pressing the pressing groove 7. Heating melts the second adhesive layer 8 and achieves connection. Pressing the pressing groove 7 can force the two sides inside the protruding groove 6 to form a tightness. The tightness causes the protruding groove 6 to be impacted and broken, and the internal flame-retardant gas 9 and flame-retardant material 10 can be ejected. The flame-retardant material 10 is located on both sides of the pressing groove 7.

[0042] In this embodiment, the inert gas is nitrogen and the chemical gas is xenon;

[0043] In this embodiment, the dry powder is an inorganic salt, and the metal powder is sodium chloride;

[0044] In this embodiment, the first bonding layer 5 and the second bonding layer 8 are both made of polypropylene. The heating temperature of the pressing position of the second bonding layer 8 is 100°C. The pressing device presses the pressing groove 7 and makes the second bonding layer 8 adhere to the upper end of the second protective layer 2 for 5 minutes.

[0045] A method for producing a high-safety outer coating to prevent lithium battery combustion includes the following steps:

[0046] Step 1: Cut the metal layer 4 and the nylon layer 3, and then use adhesive material to attach and combine the metal layer 4 and the nylon layer 3 together to form a support for the entire lithium battery outer film. The metal layer 4 increases the strength of the lithium battery outer film, and the nylon layer 3 can block the infiltration of water vapor, thus preventing water vapor from penetrating and protecting the inside of the battery cell.

[0047] Step 2: Mix and stir polyester, polyimide and polyethylene. Wash and dry the mixture of polyester, polyimide and polyethylene. After drying, pour the mixture into a high-temperature melt extruder, melt it into a colloid and extrude it.

[0048] Step 3: Extrusion and pressing to form a sheet. After cooling, the sheet is fed into a longitudinal stretching machine, which stretches the sheet longitudinally to make it thinner and form a film with a certain mechanical strength.

[0049] Step 4: Divide the sheet into two equal parts. One part is used as the second protective layer 2 and left to stand for use. The other part is formed with a recessed protrusion groove 6 by impact and is used as the first protective layer 1. Heat treat the two sheets. The heat treatment is mainly to eliminate the internal stress of the film and improve its dimensional stability and mechanical strength. At the same time, the heat treatment can also achieve the drying and purification of the film.

[0050] Step 5: Cool the heat-treated film to room temperature to eliminate the heat and stress generated during the heat treatment process;

[0051] Step 6: Lay the second protective layer 2, which was not impacted in Step 4, flat on the upper end of the nylon layer 3 and adhere it to the upper end of the nylon layer 3. Lay the material that integrates the second protective layer 2, the nylon layer 3 and the metal layer 4 flat inside the sealed device. Pour the flame retardant material 10 array onto the upper end of the second protective layer 2.

[0052] Step 7: Move the first protective layer 1, which was dented and protruded in step 4, toward the second protective layer 2, so that the dented position is aligned with the second protective layer 2 and the flame retardant material 10 placed on the upper end of the second protective layer 2 in step 6.

[0053] Step 8: Fill the sealing device with flame-retardant gas 9. The flame-retardant gas 9 will cause the protruding groove 6 to expand, so as to avoid affecting the adhesion of the first protective layer 1 and the second protective layer 2. Apply glue before the first protective layer 1 and the second protective layer 2 come into contact. Apply the second bonding layer 8 at the middle position of the lower end of the protruding groove 6 so that the first protective layer 1 and the second protective layer 2 are bonded and combined in the expanded state of the protruding groove 6.

[0054] Step 9: The stamping device extrudes the protruding groove 6 at the position corresponding to the second bonding layer 8, so that the second bonding layer 8 adheres to the second protective layer 2. At the same time, the stamping device generates high temperature at the contact position with the first protective layer 1, which melts the second bonding layer 8 and causes the protruding groove 6 to stick to the second protective layer 2. The pressing groove 7 formed by pressing can improve the tightness of the protruding grooves 6 on both sides.

[0055] Step 10: Apply a first adhesive layer 5 to the lower end of the metal layer 4. When it is subsequently attached to the battery surface, the first adhesive layer 5 adheres to the battery and is heated. After the first adhesive layer 5 melts, the structure of the first protective layer 1, the second protective layer 2, the nylon layer 3 and the metal layer 4 as a whole is fixed to the battery surface.

[0056] Step 11: Test various performance indicators of the lithium battery separator, such as thickness, porosity, air permeability, and mechanical strength. Products that pass the test can be sold on the market. The slitting and packaging process mainly involves slitting and packaging the rolled film according to certain size requirements to meet the needs of different battery models and specifications. The tested and inspected films are then rolled into rolls of a certain diameter.

[0057] Example 2: The flame-retardant gas 9 is composed of the following raw materials in parts by weight: 15 parts of inert gas, 5 parts of chemical gas and 10 parts of carbon dioxide. Other components are the same as in Example 1, and the optical film is prepared using the same preparation method.

[0058] Example 3: The flame-retardant gas 9 is composed of the following raw materials in parts by weight: 10 parts of inert gas, 5 parts of chemical gas and 15 parts of carbon dioxide. Other components are the same as in Example 1, and the optical film is prepared using the same preparation method.

[0059] Example 4: The flame-retardant gas 9 is composed of the following raw materials in parts by weight: 10 parts of inert gas, 15 parts of chemical gas and 5 parts of carbon dioxide. Other components are the same as in Example 1, and the optical film is prepared using the same preparation method.

[0060] Comparative Example 1: The flame-retardant gas 9 is composed of the following raw materials in parts by weight: 10 parts inert gas, 10 parts chemical gas, and other components are the same as in Example 1, and the optical film is prepared using the same preparation method.

[0061] Comparative Example 2: The flame-retardant gas 9 is composed of the following raw materials in parts by weight: 10 parts inert gas, 10 parts carbon dioxide, and other components are the same as in Example 1, and the optical film is prepared using the same preparation method.

[0062] Comparative Example 3: Flame-retardant gas 9 is composed of the following raw materials in parts by weight: 15 parts inert gas, 5 parts chemical gas and 10 parts carbon dioxide;

[0063] In this embodiment, there is no pressing groove 7 created by pressing, and no second adhesive layer 8 for adhering and applying to the pressing groove 7. The application of the second adhesive layer 8 in step eight is unnecessary, and the pressing of the pressing groove 7 in step nine is unnecessary. Other components are the same as in embodiment one.

[0064] The optical films described above were subjected to performance tests, and the following performance test table was obtained:

[0065]

[0066] As can be seen from the table above, the flame-retardant gas 9 in Examples 1 to 4, after being punctured, has a lower flame-suppressing and extinguishing effect than the flame-retardant gas 9 in the comparative example. Among them, the flame-retardant gas 9 in Example 2 has the highest flame-retardant efficiency. Compared with Examples 1, 3 and 4, the lack of inert gas filling reduces the ability of the flame-retardant gas 9 to extinguish the flame when the gas inside the flame-retardant gas 9 is ejected and covers the combustion point. The specification increases the proportion of inert gas in the flame-retardant gas 9, which helps the flame-retardant gas 9 to cover the collision position and contact the ignition point after the lithium battery is impacted and burns due to a short circuit, thus suppressing the flame. This shows that increasing the proportion of inert gas inside the flame-retardant gas 9 can improve the flame suppression effect and efficiency.

[0067] As can be seen from the table above, in Comparative Example 1, the lack of carbon dioxide gas will reduce the volume of the flame-retardant gas 9, reduce the speed of gas ejection, and thus reduce the flame suppression speed. In Comparative Example 2, the lack of chemical gas with good flame suppression effect will cause the gas to contact the flame burning position at a low speed after being punctured, further reducing the flame suppression speed. The instruction manual states that the reduction of the amount of flame-retardant gas 9 will reduce the ejection speed and flame suppression efficiency.

[0068] As can be seen from the table above, compared with the best-performing Example 2, Comparative Example 3 has the same gas ratio at the position of the flame-retardant gas 9. The difference is that the middle position inside the protruding groove 6 was not pressed after being filled with gas to form a pressing groove 7. Without pressing and forming a pressing groove 7, the tightness of the protruding groove 6 is reduced, which reduces the outflow rate of the flame-retardant gas 9 after the protruding groove 6 breaks. The reduced outflow rate of the flame-retardant gas 9 will also reduce the spraying rate of the flame-retardant material 10. On the other hand, the pressing groove 7 formed by pressing also helps with the roll-up storage of the battery outer film. This indicates that the pressing groove 7 can serve as the bending position of the entire protruding groove 6 and the source of tightness of the protruding groove 6, which facilitates the storage of the battery outer film and also helps to improve the subsequent flame suppression capability.

[0069] In summary, the present invention proposes a high-safety outer coating to prevent lithium battery combustion. It uses a pressing groove 7 as support to keep the protruding groove 6 taut. During the manufacturing of the battery outer coating, flame-retardant gas 9 and flame-retardant material 10 are filled into the protruding groove 6. When an external foreign object impacts the first bonding layer 5 and punctures the battery outer coating, the gas inside the taut protruding groove 6 will be ejected, carrying with it the flame-retardant material 10. This ejected gas covers the punctured area, actively suppressing flame combustion. By ejecting the gaseous and particulate media that suppress the flame, the combustion of the flame is limited, improving the safety of the battery during use without hindering its normal operation.

[0070] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for producing a high-safety outer coating to prevent lithium battery combustion, characterized in that: Includes the following steps: Step 1: Cut the metal layer (4) and the nylon layer (3), and use adhesive material to attach and combine the metal layer (4) and the nylon layer (3) together to form a support for the entire lithium battery outer film. The metal layer (4) increases the strength of the lithium battery outer film, and the nylon layer (3) can block the infiltration of water vapor, thus preventing water vapor from penetrating and protecting the inside of the battery cell. Step 2: Mix and stir polyester, polyimide and polyethylene. Wash and dry the mixture of polyester, polyimide and polyethylene. After drying, pour the mixture into a high-temperature melt extruder, melt it into a colloid and extrude it. Step 3: Extrusion and pressing to form a sheet. After cooling, the sheet is fed into a longitudinal stretching machine, which stretches the sheet longitudinally. Step 4: Divide the sheet into two equal parts. One part is used as the second protective layer (2) and left to stand for use. The other part is formed with a recessed protrusion groove (6) by impact and is used as the first protective layer (1). Heat treat the two parts of the sheet. Step 5: Cool the heat-treated film to room temperature to eliminate the heat and stress generated during the heat treatment process; Step 6: Lay the second protective layer (2) that was not impacted in step 4 on the upper end of the nylon layer (3) and stick it to the upper end of the nylon layer (3). Lay the material that integrates the second protective layer (2), the nylon layer (3) and the metal layer (4) into a sealed device. Pour the flame retardant material (10) array onto the upper end of the second protective layer (2). Step 7: Move the first protective layer (1) with the dented protrusion groove (6) formed by the impact in step 4 toward the second protective layer (2), align the dented position with the second protective layer (2), and align it with the flame retardant material (10) placed at the upper end of the second protective layer (2) in step 6. Step 8: Fill the sealing device with flame-retardant gas (9). The flame-retardant gas (9) will cause the protruding groove (6) to expand, so as to avoid affecting the adhesion of the first protective layer (1) and the second protective layer (2). Apply glue before the first protective layer (1) and the second protective layer (2) come into contact. Apply the second bonding layer (8) at the middle position of the lower end of the protruding groove (6) so that the first protective layer (1) and the second protective layer (2) are bonded and combined when the protruding groove (6) is in an expanded state. Step 9: The stamping device extrudes the protruding groove (6) to the position corresponding to the second bonding layer (8), so that the second bonding layer (8) adheres to the second protective layer (2). The stamping device generates high temperature at the contact position with the first protective layer (1) and melts the second bonding layer (8), causing the protruding groove (6) to stick to the second protective layer (2). Step 10: A first adhesive layer (5) is applied to the lower end of the metal layer (4). When it is subsequently attached to the battery surface, the first adhesive layer (5) adheres to the battery and is heated. After the first adhesive layer (5) melts, the structure of the first protective layer (1), the second protective layer (2), the nylon layer (3) and the metal layer (4) as a whole is fixed to the battery surface. Step 11: Test the various performance indicators of the lithium battery separator. The slitting and packaging process mainly involves slitting and packaging the wound film according to certain size requirements.

2. A high-safety outer coating for preventing lithium battery combustion, manufactured using the production method of the high-safety outer coating for preventing lithium battery combustion as described in claim 1, characterized in that, The material includes a first bonding layer (5), a metal layer (4) and a nylon layer (3) arranged sequentially from bottom to top. The metal layer (4) is made of aluminum. A second protective layer (2) is provided at the upper end of the nylon layer (3). A first protective layer (1) is provided at the upper end of the second protective layer (2). A flame-retardant gas (9) is arranged in an array inside the first protective layer (1) facing the second protective layer (2). A protruding groove (6) is provided on the outside of the flame-retardant gas (9). Flame-retardant material (10) is filled on both sides inside the flame-retardant gas (9).

3. The high-safety outer coating for preventing lithium battery combustion according to claim 2, characterized in that: The flame-retardant gas (9) is composed of the following parts by weight of raw materials: 10-20 parts of inert gas, 10-20 parts of chemical gas and 10-20 parts of carbon dioxide. The flame-retardant material (10) is composed of the following parts by weight of raw materials: 5-10 parts of dry powder and 5-10 parts of metal powder.

4. The high-safety outer coating for preventing lithium battery combustion according to claim 2, characterized in that: The first protective layer (1) and the second protective layer (2) are both composed of a mixture of polyester, polyimide and polyethylene, wherein the mass ratio of polyester, polyimide and polyethylene is 1:1:

1.

5. The high-safety outer coating for preventing lithium battery combustion according to claim 2, characterized in that: The protruding groove (6) and the first protective layer (1) are an integral structure. The horizontal height of the protruding groove (6) is no more than two millimeters. A pressing groove (7) is provided in the middle of the protruding groove (6). The flame retardant material (10) is located on both sides of the pressing groove (7).

6. The high-safety outer coating for preventing lithium battery combustion according to claim 3, characterized in that: The inert gas is nitrogen.

7. The high-safety outer coating for preventing lithium battery combustion according to claim 3, characterized in that: The chemical gas is xenon.

8. The high-safety outer coating for preventing lithium battery combustion according to claim 3, characterized in that: The dry powder is an inorganic salt.

9. The high-safety outer coating for preventing lithium battery combustion according to claim 3, characterized in that: The metal powder is sodium chloride.

10. The high-safety outer coating for preventing lithium battery combustion according to claim 2, characterized in that: The lower end of the pressing groove (7) on the inner wall of the protruding groove (6) is coated with a second bonding layer (8). The first bonding layer (5) and the second bonding layer (8) are both made of polypropylene. The heating temperature of the pressing position of the second bonding layer (8) is 100°C. The pressing device continuously presses the pressing groove (7) and makes the second bonding layer (8) adhere to the upper end of the second protective layer (2) for 5-7 minutes.

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