EPDM (Ethylene-Propylene-Diene Monomer) sealing material for new energy automobile battery cell and preparation method thereof

Abstract

The invention discloses an EPDM (Ethylene-Propylene-Diene Monomer) sealing material for a battery cell of a new energy automobile and a preparation method thereof. The material comprises the following raw materials in parts by weight: 100 parts of ethylene propylene diene monomer, 10-30 parts of carbon black, 25-55 parts of a composite inorganic filler, 1-2 parts of a processing aid, 0.5-1 part of an anti-aging agent and 6-8 parts of a vulcanizing agent, the main component of the composite inorganic filler is kaolin, and the composite inorganic filler contains 10-50% by weight of barium sulfate; according to the present invention, the reasonable ratio of the components, especially the mass ratio of the ethylene propylene diene monomer to the composite inorganic filler, is accurately optimized, such that the product prepared according to the sealing rubber formula can enhance the sealing and the safety of the strong battery cell, and further has characteristics of stable performance and high qualification rate.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer materials, in particular to an EPDM sealing material for a battery cell of a new energy vehicle and a preparation method thereof. BACKGROUND

[0002] New energy vehicles are growing rapidly, and power batteries are the most core components of new energy vehicles, which are composed of hundreds of battery cells. Each battery cell needs a rubber sealing element to seal the electrolyte. Once the electrolyte leaks, the entire battery pack needs to be replaced, or even cause a serious fire, leading to a fire, and even threatening the safety of the driver and passengers.

[0003] The material of the battery cell sealing element on the market is basically peroxide-vulcanized fluororubber. This fluororubber is expensive and contains PFAS, which is an environmentally unfriendly material. PFAS has become a highly concerned and controlled substance under a series of regulations. The new energy vehicle battery industry urgently needs a new solution. Therefore, EPDM material has entered the public's field of vision. Chinese patent CN113372655B discloses a ternary ethylene-propylene sealing material for hydrogen fuel cells. Liquid ternary ethylene-propylene rubber is used as the base material, and peroxide vulcanizing agent and polycyanate accelerator are added. The obtained sealing material for hydrogen fuel cells can be vulcanized under low temperature conditions and has good mechanical properties. However, as a sealing material for battery cells, not only does it need to have good compression set resistance, high and low temperature resistance and other conventional sealing element requirements, but it also needs to have good insulation, be able to resist long-term electrolyte corrosion, and not affect the hydrogen fluoride acid index and quality of the electrolyte. Therefore, the new energy vehicle battery industry needs a sealing material that is environmentally friendly, inexpensive, has good high and low temperature resistance, insulation and compression set resistance, and is resistant to electrolyte corrosion. SUMMARY

[0004] Based on the technical problems existing in the background art, the application provides an EPDM sealing material for a battery cell of a new energy vehicle, which has good high and low temperature resistance, insulation and compression set resistance, can resist long-term electrolyte corrosion, does not affect the hydrogen fluoride acid index and quality of the electrolyte, has good processability and demouldability, and can enhance the sealing and safety of the battery cell, has stable performance and a high qualification rate.

[0005] To achieve the above purposes, the technical scheme provided by the application is as follows:

[0006] An EPDM sealing material for a battery cell of a new energy vehicle, characterized in that the raw materials include, by weight fraction: 100 parts of ternary ethylene-propylene rubber; 3-7 parts of zinc oxide; 10-30 parts of carbon black; 25-55 parts of composite inorganic filler; Processing aid 1-2 parts; Antioxidant 0.5-1 parts; Vulcanizing agent 6-8 parts.

[0007] The main component of the composite inorganic filler is kaolin, and 10%-50% by weight of barium sulfate is contained.

[0008] Further, the preparation method of the composite inorganic filler comprises: dispersing kaolin in an ethanol / water mixed solvent, adding a barium sulfate emulsion, stirring and reacting at 60-80°C for 2-4 hours, and then spray drying to obtain a composite inorganic filler powder.

[0009] Further, the average particle size of the kaolin is less than 100 nm, and the specific surface area is greater than 300 m 2 / g.

[0010] Further, the ethylene content of the EPDM rubber is 15.0%-45.0%.

[0011] Further, the Mooney viscosity of the EPDM rubber is less than 10 MU.

[0012] The application also provides a method for preparing an EPDM sealing material for a new energy automobile battery cell, comprising the following steps: S1: preparing a composite inorganic filler; dispersing kaolin in an ethanol / water mixed solvent, adding a barium sulfate emulsion, stirring and reacting at 60-80°C for 2-4 hours, and then spray drying to obtain a composite inorganic filler powder; S2: determining the proportion of key components of the composite material; the mass ratio of the EPDM rubber to the composite inorganic filler is 1:(0.25-0.55); S3: mixing the EPDM rubber and zinc oxide at 140-160°C for 3-5 minutes to form a premixed base; S4: adding carbon black and composite inorganic filler and mixing to 110-130°C; S5: adding processing aid, antioxidant and vulcanizing agent respectively, and discharging after uniform mixing.

[0013] Further, the carbon black and the composite powder are added alternately, and the interval between each addition is 30-60 seconds.

[0014] The EPDM rubber in the above technical solution is preferably Arlanxeeton KELTAN@2650C, which is a long-chain branched EPDM rubber with controllable technology from Arlanxeeton, and has excellent physical and mechanical properties and good processing performance.

[0015] The carbon black preferably uses the fast extrusion carbon black of Shanghai Cabot Chemical Co., Ltd. The carbon black has good dispersibility and high calendering performance.

[0016] The kaolin preferably uses the German Hoffman VM56.

[0017] The barium sulfate preferably uses the German Schafer Ben BLANC FIXE N.

[0018] The vulcanizing agent preferably uses the peroxide vulcanizing agent DCP40.

[0019] The beneficial effects of the present application are:

[0020] (1) The raw material of the present application specifically uses low ethylene content EPDM, which makes the obtained material have good low temperature performance; the peroxide vulcanizing system is used, which makes the obtained material have satisfactory heat aging resistance and low compression permanent deformation ability.

[0021] (2) Establish the reinforcing system: the reinforcing system reasonably matches the carbon black and the acid and alkali resistant composite inorganic filler, which not only makes the obtained material have excellent insulation performance and electrolyte resistance, but also has very good dispersibility; the kaolin is the core and the barium sulfate is the shell, the kaolin not only provides the loading for the barium sulfate, but also makes the composite material glue have strong chemical reactivity, which can make the carbon black and the composite powder further react, so that the whole glue forms a complete crosslinking network, improves the interaction force between the glue and the carbon black and the composite powder, and thus improves the mechanical properties of the composite material.

[0022] (3) The present application selects appropriate raw materials and accurately optimizes the reasonable proportioning between the components, especially the mass proportioning between the EPDM and the composite inorganic filler, so that the product made of the sealing rubber formula not only enhances the sealing and safety of the high-power battery cell, but also has stable performance and high qualification rate. DETAILED DESCRIPTION

[0023] In order to make the skilled in the art better understand the technical solutions of the present application, some non-limiting embodiments are further disclosed below to further illustrate the present application in detail.

[0024] The reagents used in the present application can be purchased from the market or can be prepared by the method described in the present application.

[0025] Example 1

[0026] The present application proposes a new energy automobile battery cell EPDM sealing material, the raw material includes by weight fraction: EPDM (Alronxinko KELTAN@2650C) 100 parts; Zinc oxide 7 parts; Carbon black (Shanghai Cabot N550) 30 parts; Kaolin (Germany Hoffmann VM56) 20 parts; Barium sulfate (Germany Shahali Ben BLANC FIXE N) 15 parts; Processing aid 1 part; Antioxidant (TMQ) 1 part; Vulcanizing agent (DCP40) 6 parts.

[0027] The material in example 1 was tested, and the test results are as follows:

[0028] Example 2

[0029] The EPDM sealing material for new energy automobile battery cell proposed by the application comprises, by weight fraction: Ethylene propylene terpolymer (Alang Xinke KELTAN@2650C) 100 parts; Zinc oxide 5 parts; Carbon black (Shanghai Cabot N550) 20 parts; Kaolin (Germany Hoffmann VM56) 30 parts; Barium sulfate (Germany Shahali Ben BLANC FIXE N) 10 parts; Processing aid 1 part; Antioxidant (TMQ) 1 part; Vulcanizing agent (DCP40) 7 parts.

[0030] The material in example 2 was tested, and the test results are as follows:

[0031] Example 3

[0032] The EPDM sealing material for new energy automobile battery cell proposed by the application comprises, by weight fraction: Ethylene propylene terpolymer (Alang Xinke KELTAN@2650C) 100 parts; Zinc oxide 3 parts; Carbon black (Shanghai Cabot N550) 10 parts; Kaolin (Germany Hoffmann VM56) 40 parts; Barium sulfate (Germany Shahali Ben BLANC FIXE N) 5 parts; Processing aid 2 parts; Antioxidant (TMQ) 0.5 parts; Vulcanizing agent (DCP40) 8 parts.

[0033] The material in Example 3 was tested, and the test results are as follows:

[0034] Comparative Example 1 The weight fraction of the remaining materials in Example 1 was unchanged, and no kaolin was added.

[0035] Comparative Example 2 The weight fraction of the remaining materials in Example 1 was unchanged, and no barium sulfate was added.

[0036] Comparative Example 3 The weight fraction of the remaining materials in Example 1 was unchanged, and no kaolin and barium sulfate were added.

[0037] The data of each item in the comparative example and the comparative examples; the results are shown in the following table.

[0038]

[0039] From the above test results, it can be seen that the reasonable collocation of the reinforcing system, carbon black and acid and alkali resistant composite inorganic fillers, makes the obtained material have excellent insulation performance and electrolyte resistance, and accurate optimization of the reasonable ratio of each component, especially the mass ratio between the ethylene-propylene-diene rubber and the composite inorganic filler, makes the product made of the sealing rubber formula not only enhance the mechanical properties, but also exhibit satisfactory heat aging resistance and low compression permanent deformation ability.

[0040] The technical solutions of the present application have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein within the content, spirit and scope of the present application to realize and apply the technical solutions of the present application. Those skilled in the art can refer to the content herein to appropriately improve the process parameters for implementation. It is particularly pointed out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present application.

Claims

1. An EPDM sealing material for new energy vehicle battery cells, characterized in that: The raw materials include by weight: 100 parts of EPDM rubber 3-7 parts zinc oxide 10-30 parts of carbon black 25-55 parts of composite inorganic filler 1-2 parts of processing aid 0.5-1 part antioxidant 6-8 parts of vulcanizing agent The composite inorganic filler is mainly composed of kaolin and contains 10% to 50% by weight of barium sulfate.

2. The EPDM sealing material according to claim 1, characterized in that The preparation method of the composite inorganic filler comprises: dispersing kaolin in an ethanol / water mixed solvent, adding barium sulfate emulsion, stirring and reacting at 60-80° C. for 2-4 hours, and spray drying to obtain composite inorganic filler powder.

3. The EPDM sealing material according to claim 2, characterized in that: The average particle size of the kaolin is less than 100 nm, and the specific surface area is greater than 300 m 2 / g.

4. The EPDM sealing material according to claim 1, characterized in that: The vinyl content of the EPDM rubber is 15.0%-45.0%.

5. The EPDM sealing material according to claim 1, characterized in that: The Mooney viscosity of the EPDM rubber is lower than 10MU.

6. A method for preparing any one of claims 1-5 EPDM sealing materials, characterized in that: The steps include: S1: preparing a composite inorganic filler; dispersing kaolin in an ethanol / water mixed solvent, adding a barium sulfate emulsion, stirring and reacting at 60-80° C. for 2-4 hours, and spray drying to obtain a composite inorganic filler powder; S2: Determine the ratio of key components of the composite material; the mass ratio of EPDM rubber to composite inorganic filler in the component is 1:(0.25-0.55); S3: kneading EPDM rubber and zinc oxide at 140-160° C. for 3-5 minutes to form a premixed matrix; S4: Add carbon black and composite inorganic filler, and mix to 110-130°C; S5: Add processing aid, antioxidant and vulcanizing agent respectively, mix well and then discharge the glue.

7. The method according to claim 6, characterized in that Carbon black and composite powder are added alternately, with an interval of 30-60 seconds between each addition.

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