Packaging material suitable for lithium battery core and preparation method of packaging material

Abstract

The invention discloses a packaging material suitable for a lithium battery core and a preparation method thereof, the packaging material is composed of a flame-retardant shell and a flame-retardant insulating glue solution arranged in the flame-retardant shell, the flame-retardant shell is made of flame-retardant plastic, and the flame-retardant insulating glue solution is composed of a flame-retardant powder material and a liquid insulating resin glue. The packaging material disclosed by the invention is good in flame-retardant effect, good in insulating property and good in explosion-proof effect, and can effectively solve the safety problems of fire, explosion and the like caused by short circuit due to the fact that external sharp substances (such as steel needles, iron nails and the like) pierce a lithium battery core package and a lithium battery core.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery core packaging materials, and relates to a packaging material suitable for lithium battery cores and a preparation method thereof, and in particular to a flame retardant and explosion-proof packaging material suitable for lithium battery cores and a preparation method thereof. Background Art

[0002] Lithium batteries have always been a hot topic in the field of new energy at home and abroad due to their advantages such as high energy density, long service life, fast charging speed, large capacity, and no memory effect. They have been widely used in various industries such as automobiles, electronic appliances, etc. However, in actual applications, it is found that most lithium battery cells will quickly catch fire and explode after being punctured by external sharp objects (such as steel needles, nails, blades, etc.). For example, lithium batteries in electric vehicles may catch fire and explode when they are touched by sharp objects during driving, and lithium batteries in electronic components may catch fire and explode when they are touched by sharp objects. The reason is that after external objects puncture the lithium battery core, it will cause an internal short circuit in the lithium battery, causing a large amount of heat to be generated inside the lithium battery instantly, and the temperature rises rapidly, thereby igniting the electrolyte or diaphragm, causing fire and combustion until explosion. This phenomenon needs to be especially prevented in high-power lithium batteries, otherwise it will cause major safety accidents.

[0003] At present, the lithium battery industry mainly prevents lithium battery cells from catching fire and exploding due to being punctured by sharp external objects by reserving pressure relief valves on lithium batteries, adding flame retardants to electrolytes, optimizing the formulation of positive and negative electrode materials, or improving the flame retardant properties of diaphragms. Although these methods have improved the safety of lithium battery cells to a certain extent, the effect is not significant, because there are very few flame retardant materials that can be added to diaphragms, electrolytes, or positive and negative electrode materials. Adding too much will affect the electrical performance. Therefore, how to solve the problem of fire and explosion caused by needle puncture or sharp external objects puncturing batteries in the field of lithium batteries (especially power lithium batteries) has always been a major problem that has plagued the industry. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a packaging material suitable for lithium battery cells with good flame retardant effect, good insulation performance and good explosion-proof effect and a preparation method thereof. The packaging material can effectively solve the safety problems such as fire and explosion caused by short circuit caused by sharp external objects (such as steel needles, iron nails, etc.) piercing the lithium battery cell packaging and the lithium battery cell.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A packaging material suitable for lithium battery cores, the packaging material consists of a flame-retardant shell and a flame-retardant insulating glue liquid arranged in the flame-retardant shell, the flame-retardant shell is made of flame-retardant plastic, and the flame-retardant insulating glue liquid consists of flame-retardant powder material and liquid insulating resin glue.

[0007] The above-mentioned packaging material suitable for lithium battery cores, preferably, the mass ratio of the flame retardant powder material to the liquid insulating resin glue is 1-10:1-15.

[0008] The above-mentioned packaging material suitable for lithium battery cells, preferably, the flame retardant powder material includes one or more of magnesium hydroxide powder, ammonium polyphosphate powder and mica powder; the liquid insulating resin glue includes one or more of dimethyl silicone oil, liquid silicone, polyurethane liquid glue, epoxy resin liquid glue and acrylic resin liquid glue, wherein the multiple refers to multiple materials mixed in any proportion.

[0009] The above-mentioned packaging material suitable for lithium battery cells, preferably, the flame retardant plastic includes one or more of flame retardant polyethylene, flame retardant polypropylene, flame retardant polystyrene, flame retardant polyurethane, flame retardant epoxy resin, flame retardant polyester, flame retardant polycarbonate and flame retardant polyvinyl chloride, wherein multiple refers to multiple materials mixed in any proportion.

[0010] The above-mentioned packaging material suitable for lithium battery cells, preferably, the flame retardant shell is a thin-walled square flame retardant shell, and the wall thickness of the thin-walled square flame retardant shell is 0.1mm≤≤10mm.

[0011] The above-mentioned packaging material suitable for lithium battery cores, preferably, the inner cavity width of the flame retardant shell is ≥0.5mm.

[0012] The above-mentioned packaging material suitable for lithium battery core is preferably arranged outside the lithium battery core by bonding or welding.

[0013] As a general technical concept, the present invention also provides a method for preparing the above-mentioned packaging material suitable for lithium battery cores, comprising the following steps:

[0014] (1) Using flame-retardant plastic as raw material to prepare a flame-retardant shell;

[0015] (2) The flame retardant powder material and the liquid insulating resin glue are mixed to form a flame retardant insulating glue liquid, which is then injected into the flame retardant shell and sealed to obtain a packaging material suitable for a lithium battery cell.

[0016] In the above-mentioned method for preparing a packaging material suitable for a lithium battery cell, preferably, in step (1), the molding method includes injection molding or 3D printing.

[0017] In the above-mentioned method for preparing a packaging material suitable for lithium battery cores, preferably, in step (2), the injection method is injection.

[0018] In the present invention, the length and height of the inner cavity of the flame retardant shell can be adjusted according to the length and height of the lithium battery core to meet the needs of lithium battery core packaging.

[0019] The main innovative features of the present invention are:

[0020] In the prior art, most lithium battery cells will quickly catch fire and explode after being punctured by external sharp objects (such as steel needles, nails, blades, etc.), seriously affecting safety. However, the entire industry has not yet found an effective solution, which has become a technical bottleneck restricting the development of the industry. After long-term arduous research and experiments, the applicant creatively proposed a new solution from the perspective of lithium battery cell packaging, designed and manufactured a packaging material injected with a flame-retardant insulating glue (preferably high viscosity), and used the packaging material to package lithium battery cells. After the external sharp object punctures the packaging material, a layer of insulating flame-retardant material will adhere to its surface, so that the surface of the sharp object that punctures the lithium battery core is insulated, thereby avoiding causing a short circuit inside the lithium battery core. In addition, when the sharp object punctures the lithium battery core, the flame-retardant insulating glue in the packaging material flows into the lithium battery core, further improving the flame retardancy and insulation inside the lithium battery core, thereby effectively solving the problem of fire, combustion and explosion after the external sharp object punctures the lithium battery core, showing a huge prospect for industrial application.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] (1) The present invention provides a packaging material suitable for lithium battery cells, the packaging material is composed of a flame retardant shell (preferably a thin-walled square flame retardant shell) and a flame retardant insulating adhesive, the flame retardant insulating adhesive is encapsulated in the flame retardant shell, and the packaging material has the characteristics of good flame retardant effect, good insulation performance, good explosion-proof effect, etc. When the packaging material is used as a packaging container for lithium battery cells, it can effectively solve the safety problems such as fire and explosion caused by short circuit caused by external sharp objects (such as steel needles, iron nails, etc.) piercing the lithium battery cell packaging and the lithium battery cell.

[0023] (2) The method for preparing the packaging material suitable for lithium battery cells of the present invention has the advantages of being environmentally friendly, low cost, simple and controllable process, and easy to realize industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the cross-sectional structure of a packaging material suitable for a lithium battery cell according to Example 1 of the present invention.

[0025] Figure 2 This is a schematic structural diagram of a lithium battery cell packaged with a packaging material suitable for a lithium battery cell in Example 1 of the present invention.

[0026] Legend:

[0027] 1. Flame retardant shell; 2. Flame retardant insulating glue; 3. Lithium battery core. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0029] Example 1

[0030] A packaging material suitable for lithium battery core of the present invention, such as Figure 1 As shown, the packaging material consists of a flame-retardant outer shell 1 and a flame-retardant insulating adhesive liquid 2 arranged in the flame-retardant outer shell 1. The flame-retardant outer shell 1 is made of flame-retardant plastic, and the flame-retardant insulating adhesive liquid 2 is made of flame-retardant powder material and liquid insulating resin adhesive.

[0031] In this embodiment, the flame retardant plastic is flame retardant polyethylene.

[0032] In this embodiment, the flame retardant powder material is magnesium hydroxide powder and ammonium polyphosphate powder, and the liquid insulating resin adhesive is dimethyl silicone oil and liquid silicone. The mass ratio of the flame retardant powder material to the liquid insulating resin adhesive is 1:1, and the mass ratio of magnesium hydroxide powder, ammonium polyphosphate powder, dimethyl silicone oil, and liquid silicone is 1:1:1:1.

[0033] In this embodiment, the flame retardant shell 1 is a thin-walled square flame retardant shell, the wall thickness of the thin-walled square flame retardant shell is 0.1mm, the shell is a hollow structure, and the inner cavity width is 0.5mm. The cross section of the shell is rectangular, and the length and height of the shell can be determined according to the size of the lithium battery core.

[0034] A method for preparing a packaging material suitable for a lithium battery cell of this embodiment comprises the following steps:

[0035] (1) Using flame-retardant plastic as raw material, a flame-retardant shell 1 is prepared by 3D printing;

[0036] (2) Magnesium hydroxide powder, ammonium polyphosphate powder, dimethyl silicone oil and liquid silica gel are mixed in proportion and stirred for 30 minutes to form a flame retardant insulating adhesive 2, and the flame retardant insulating adhesive 2 is injected into the flame retardant shell 1 by injection technology. An injection hole can be set on the flame retardant shell 1. After the flame retardant insulating adhesive 2 fills the flame retardant shell 1, the injection hole is sealed with a hole cover to obtain a packaging material suitable for lithium battery cells.

[0037] In this embodiment, Figure 2 As shown, the packaging material can be prepared by fusion welding technology into a square packaging container with a length of 5 cm, an inner cavity width of 1 cm (suitable for 1 cm thick lithium battery cells), and a height of 8 cm, and the packaging container is encapsulated with a lithium battery cell.

[0038] Test: The packaging container and lithium battery core were pierced with a steel needle, and no combustion or explosion occurred.

[0039] Example 2

[0040] The invention discloses a packaging material suitable for lithium battery cells. The packaging material comprises a flame-retardant outer shell 1 and a flame-retardant insulating adhesive liquid 2 arranged in the flame-retardant outer shell 1. The flame-retardant outer shell 1 is made of flame-retardant plastic, and the flame-retardant insulating adhesive liquid 2 is made of flame-retardant powder material and liquid insulating resin adhesive.

[0041] In this embodiment, the flame retardant plastic is flame retardant polypropylene.

[0042] In this embodiment, the flame retardant powder material is mica powder and ammonium polyphosphate powder, and the liquid insulating resin adhesive is dimethyl silicone oil and polyurethane liquid adhesive. The mass ratio of the flame retardant powder material to the liquid insulating resin adhesive is 3:5, and the mass ratio of the mica powder, ammonium polyphosphate powder, dimethyl silicone oil, and polyurethane liquid adhesive is 1:2:2:3.

[0043] In this embodiment, the flame retardant shell 1 is a thin-walled square flame retardant shell, the wall thickness of the thin-walled square flame retardant shell is 0.2mm, the shell is a hollow structure, and the inner cavity width is 0.6mm. The cross-section of the shell is rectangular, and the length and height of the shell can be determined according to the size of the lithium battery core.

[0044] A method for preparing a packaging material suitable for a lithium battery cell of this embodiment comprises the following steps:

[0045] (1) Using flame-retardant plastic as raw material, a flame-retardant housing 1 is prepared by hollow injection molding;

[0046] (2) Mica powder, ammonium polyphosphate powder, dimethyl silicone oil and polyurethane liquid glue are mixed in proportion and stirred for 60 minutes to form a flame retardant insulating adhesive liquid 2, and the flame retardant insulating adhesive liquid 2 is injected into the flame retardant shell 1 by injection technology. An injection hole can be set on the flame retardant shell 1. After the flame retardant insulating adhesive liquid 2 fills the flame retardant shell 1, the injection hole is sealed with a hole cover to obtain a packaging material suitable for lithium battery cells.

[0047] In this embodiment, the packaging material can be prepared into a square packaging container with a length of 3 cm, an inner cavity width of 2 cm, and a height of 8 cm by fusion welding technology, and a lithium battery cell is encapsulated in the packaging container.

[0048] Test: The packaging container and lithium battery core were pierced with an iron nail, but no combustion or explosion occurred.

[0049] Example 3

[0050] The invention discloses a packaging material suitable for lithium battery cells. The packaging material comprises a flame-retardant outer shell 1 and a flame-retardant insulating adhesive liquid 2 arranged in the flame-retardant outer shell 1. The flame-retardant outer shell 1 is made of flame-retardant plastic, and the flame-retardant insulating adhesive liquid 2 is made of flame-retardant powder material and liquid insulating resin adhesive.

[0051] In this embodiment, the flame retardant plastic is flame retardant polystyrene.

[0052] In this embodiment, the flame retardant powder material is mica powder, ammonium polyphosphate powder and magnesium hydroxide powder, and the liquid insulating resin glue is dimethyl silicone oil, liquid silicone and polyurethane liquid glue. The mass ratio of the flame retardant powder material to the liquid insulating resin glue is 4:6, and the mass ratio of the mica powder, ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silicone and polyurethane liquid glue is 1:2:1:2:1:3.

[0053] In this embodiment, the flame retardant shell 1 is a thin-walled square flame retardant shell, the wall thickness of the thin-walled square flame retardant shell is 0.5 mm, the shell is a hollow structure, and the inner cavity width is 1.5 mm. The cross-section of the shell is rectangular, and the length and height of the shell can be determined according to the size of the lithium battery core.

[0054] A method for preparing a packaging material suitable for a lithium battery cell of this embodiment comprises the following steps:

[0055] (1) Using flame-retardant plastic as raw material, a flame-retardant shell 1 is prepared by a 3D printing method;

[0056] (2) Mica powder, ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silicone and polyurethane liquid glue are mixed in proportion and stirred for 50 minutes to form a flame retardant insulating adhesive liquid 2, and the flame retardant insulating adhesive liquid 2 is injected into the flame retardant shell 1 by injection technology. An injection hole can be set on the flame retardant shell 1. After the flame retardant insulating adhesive liquid 2 fills the flame retardant shell 1, the injection hole is sealed with a hole cover to obtain a packaging material suitable for lithium battery cells.

[0057] In this embodiment, the packaging material can be prepared into a square packaging container with a length of 5 cm, an inner cavity width of 3 cm, and a height of 8 cm by fusion welding technology, and a lithium battery cell is encapsulated in the packaging container.

[0058] Test: The packaging container and lithium battery core were pierced with a steel needle, and no combustion or explosion occurred.

[0059] Example 4

[0060] The invention discloses a packaging material suitable for lithium battery cells. The packaging material comprises a flame-retardant outer shell 1 and a flame-retardant insulating adhesive liquid 2 arranged in the flame-retardant outer shell 1. The flame-retardant outer shell 1 is made of flame-retardant plastic, and the flame-retardant insulating adhesive liquid 2 is made of flame-retardant powder material and liquid insulating resin adhesive.

[0061] In this embodiment, the flame retardant plastic is flame retardant polyvinyl chloride.

[0062] In this embodiment, the flame retardant powder material is mica powder, ammonium polyphosphate powder and magnesium hydroxide powder, and the liquid insulating resin glue is dimethyl silicone oil, liquid silicone and epoxy resin liquid glue. The mass ratio of the flame retardant powder material to the liquid insulating resin glue is 6:8, and the mass ratio of the mica powder, ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silicone and epoxy resin liquid glue is 2:1:3:3:2:3.

[0063] In this embodiment, the flame retardant shell 1 is a thin-walled square flame retardant shell, the wall thickness of the thin-walled square flame retardant shell is 1mm, the shell is a hollow structure, and the inner cavity width is 3mm. The cross section of the shell is rectangular, and the length and height of the shell can be determined according to the size of the lithium battery core.

[0064] A method for preparing a packaging material suitable for a lithium battery cell of this embodiment comprises the following steps:

[0065] (1) Using flame-retardant plastic as raw material, a flame-retardant shell 1 is prepared by a 3D printing method;

[0066] (2) Mica powder, ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silica gel and epoxy resin liquid glue are mixed in proportion and stirred for 30 minutes to form a flame retardant insulating glue solution 2, and the flame retardant insulating glue solution 2 is injected into the flame retardant shell 1 by injection technology. After the flame retardant insulating glue solution 2 fills the flame retardant shell 1, it is sealed to obtain a packaging material suitable for lithium battery cells.

[0067] In this embodiment, the packaging material can be prepared into a square packaging container with a length of 5 cm, an inner cavity width of 5 cm, and a height of 8 cm by fusion welding technology, and a lithium battery core is encapsulated in the packaging container.

[0068] Test: The packaging container and lithium battery core were pierced with a steel needle, and no combustion or explosion occurred.

[0069] Example 5

[0070] The invention discloses a packaging material suitable for lithium battery cells. The packaging material comprises a flame-retardant outer shell 1 and a flame-retardant insulating adhesive liquid 2 arranged in the flame-retardant outer shell 1. The flame-retardant outer shell 1 is made of flame-retardant plastic, and the flame-retardant insulating adhesive liquid 2 is made of flame-retardant powder material and liquid insulating resin adhesive.

[0071] In this embodiment, the flame retardant plastic is flame retardant polyester.

[0072] In this embodiment, the flame retardant powder material is ammonium polyphosphate powder and magnesium hydroxide powder, and the liquid insulating resin glue is dimethyl silicone oil, liquid silicone and epoxy resin liquid glue. The mass ratio of the flame retardant powder material to the liquid insulating resin glue is 5:9, and the mass ratio of ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silicone and epoxy resin liquid is 2:3:2:5:2.

[0073] In this embodiment, the flame retardant shell 1 is a thin-walled square flame retardant shell, the wall thickness of the thin-walled square flame retardant shell is 1mm, the shell is a hollow structure, and the inner cavity width is 5mm. The cross section of the shell is rectangular, and the length and height of the shell can be determined according to the size of the lithium battery core.

[0074] A method for preparing a packaging material suitable for a lithium battery cell of this embodiment comprises the following steps:

[0075] (1) Using flame-retardant plastic as raw material, a flame-retardant housing 1 is prepared by injection molding;

[0076] (2) Ammonium polyphosphate powder, magnesium hydroxide powder, dimethyl silicone oil, liquid silica gel and epoxy resin liquid are mixed in proportion and stirred for 60 minutes to form a flame retardant insulating adhesive 2, and the flame retardant insulating adhesive 2 is injected into the flame retardant shell 1 by injection technology. After the flame retardant insulating adhesive 2 fills the flame retardant shell 1, it is sealed to obtain a packaging material suitable for lithium battery cells.

[0077] In this embodiment, the packaging material can be prepared into a square packaging container with a length of 6 cm, an inner cavity width of 6 cm, and a height of 10 cm by fusion welding technology, and a lithium battery cell is encapsulated in the packaging container.

[0078] Test: The packaging container and lithium battery core were pierced with a steel needle, and no combustion or explosion occurred.

[0079] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A packaging material suitable for lithium battery cells, characterized in that: The packaging material consists of a flame-retardant outer shell (1) and a flame-retardant insulating adhesive liquid (2) arranged in the flame-retardant outer shell (1); the flame-retardant outer shell (1) is made of flame-retardant plastic; and the flame-retardant insulating adhesive liquid (2) is made of flame-retardant powder material and liquid insulating resin adhesive.

2. The packaging material for lithium battery cells according to claim 1, characterized in that: The mass ratio of the flame retardant powder material to the liquid insulating resin adhesive is 1-10:1-15.

3. The packaging material for lithium battery cells according to claim 1, characterized in that: The flame retardant powder material includes one or more of magnesium hydroxide powder, ammonium polyphosphate powder and mica powder; the liquid insulating resin glue includes one or more of dimethyl silicone oil, liquid silicone, polyurethane liquid glue, epoxy resin liquid glue and acrylic resin liquid glue.

4. The packaging material for lithium battery cells according to claim 1, characterized in that: The flame retardant plastic includes one or more of flame retardant polyethylene, flame retardant polypropylene, flame retardant polystyrene, flame retardant polyurethane, flame retardant epoxy resin, flame retardant polyester, flame retardant polycarbonate and flame retardant polyvinyl chloride.

5. The packaging material for lithium battery core according to any one of claims 1 to 4, characterized in that: The flame retardant shell (1) is a thin-walled square flame retardant shell, and the wall thickness of the thin-walled square flame retardant shell is 0.1 mm≤≤10 mm.

6. The packaging material for lithium battery core according to any one of claims 1 to 4, characterized in that: The inner cavity width of the flame retardant outer shell (1) is ≥0.5 mm.

7. The packaging material for lithium battery core according to any one of claims 1 to 4, characterized in that: The packaging material is arranged outside the lithium battery core (3) by bonding or welding.

8. A method for preparing a packaging material suitable for a lithium battery core according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Using flame-retardant plastic as raw material, preparing and molding a flame-retardant outer shell (1); (2) The flame retardant powder material and the liquid insulating resin glue are mixed to form a flame retardant insulating glue liquid (2), which is then injected into the flame retardant shell (1) and sealed to obtain a packaging material suitable for a lithium battery cell.

9. The method for preparing a packaging material suitable for a lithium battery cell according to claim 8, characterized in that: In step (1), the molding method includes injection molding or 3D printing.

10. The method for preparing a packaging material suitable for lithium battery core according to claim 8 or 9, characterized in that: In step (2), the injection method is injection.

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