Organosilicon laminates and batteries

Abstract

This invention provides an organosilicon laminate (1) formed by stacking layers comprising a silicone rubber layer (A)(2) and an organosilicon layer (B)(3) with a lower hardness than the silicone rubber layer (2). The organosilicon layer (B)(3) is at least one layer selected from an organosilicon sponge layer (B1) and an organosilicon gel layer (B2). Both the silicone rubber layer (A)(2) and the organosilicon layer (B)(3) are formed of a material that maintains its shape by ceramization during combustion and becoming a sintered body. The organosilicon laminate (1) is fire-resistant. The silicone rubber layer (A)(2) and the organosilicon layer (B)(3) are stacked alternately, preferably with two or more layers of each, totaling four or more layers. This provides an organosilicon laminate with high fire resistance and high compression resistance as a buffer material for batteries.

Description

Technical Field

[0001] This invention relates to organosilicon laminates that can be used in buffer materials between battery cells, etc. Background Technology

[0002] In recent years, electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs), which have seen increasing demand and production, use electricity from batteries as their energy source and are powered by electric motors. Batteries typically consist of multiple battery cells housed within a battery casing. Batteries are designed to handle various abnormal scenarios, including abnormal heating such as thermal runaway. If abnormal heating occurs, there are concerns that the cell materials may deform or break due to cell expansion.

[0003] Patent Document 1 discloses a flame-retardant thermal expansion component with a thermal conductivity of 1 W / m·K or higher below 80°C and 0.5 W / m·K or lower above 80°C. Patent Document 2 discloses filling the open space of a battery module container with a foam containing silicone rubber adhesive and hollow glass beads. Patent Document 3 discloses a heat sink for dissipating battery heat, comprising cylindrical, U-shaped, or spiral heat sink fins, cushioning material, and an adhesive layer.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-172762

[0007] Patent Document 2: Japanese Patent Publication No. 2020-507194

[0008] Patent Document 3: Japanese Patent Application Publication No. 2021-015696 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, the aforementioned technologies still have problems with the fire resistance and compression resistance of the battery's buffer materials, and efforts are being made to improve them.

[0011] In order to solve the above-mentioned problems, the present invention provides an organosilicon laminate with high fire resistance and compression resistance as a buffer material for batteries.

[0012] Methods for solving problems

[0013] The organosilicon laminate of the present invention is an organosilicon laminate comprising a silicone rubber layer (A) and an organosilicon layer (B) with a hardness lower than that of the silicone rubber layer, wherein the organosilicon layer (B) is at least one layer selected from an organosilicon sponge layer (B1) and an organosilicon gel layer (B2), and both the silicone rubber layer (A) and the organosilicon layer (B) are formed of a material that maintains its shape by ceramizing during combustion and becoming a sintered body, and the organosilicon laminate has fire resistance.

[0014] Invention Effects

[0015] This invention relates to an organosilicon laminate comprising a silicone rubber layer (A) and an organosilicon layer (B) with a lower hardness than the silicone rubber layer. The organosilicon layer (B) is at least one layer selected from an organosilicon sponge layer (B1) and an organosilicon gel layer (B2). Both the silicone rubber layer (A) and the organosilicon layer (B) are formed from a material that maintains its shape by ceramization during combustion, becoming a sintered body. The organosilicon laminate possesses fire resistance, thus providing a battery buffer material with high fire resistance and high compressibility. These properties also prevent material deformation when the battery abnormally heats up. Attached Figure Description

[0016] [ Figure 1 ] Figure 1 (A) is a schematic cross-sectional view of an organosilicon laminate disposed between battery cells according to one embodiment of the present invention. Figure 1 (B) is Figure 1 (A) Schematic cross-sectional view of an abnormal heating event.

[0017] [ Figure 2 ] Figure 2 (A) is a schematic cross-sectional view of the battery cells of the comparative example with silicone material disposed between them. Figure 2 (B) is Figure 2 (A) Schematic cross-sectional view of an abnormal heating event.

[0018] [ Figure 3 ] Figure 3 This is a schematic cross-sectional view of a battery in one embodiment of the present invention, in which an organosilicon laminate is arranged between multiple battery cells. Detailed Implementation

[0019] The present invention is a silicone laminate formed by laminating a silicone rubber layer (A) and a silicone layer (B) having a lower hardness than the above-mentioned silicone rubber layer. Preferably, the ASKER A hardness of the silicone rubber layer (A) is 40 to 80, and preferably the ASKER C hardness of the silicone layer (B) is 30 to 70, and the hardness relationship is A > B. Thus, the silicone rubber layer (A) with a high hardness becomes the core material, and it is a material that maintains fire resistance and heat insulation while reducing deformation caused by unit expansion.

[0020] The silicone layer (B) is at least one layer selected from a silicone sponge layer (B1) and a silicone gel layer (B2). Thus, it becomes a silicone layer with a lower hardness than the silicone rubber layer (A). Both the above-mentioned silicone rubber layer (A) and the above-mentioned silicone layer (B) are formed of materials that maintain their shape by ceramizing during combustion and becoming sintered bodies. As such a silicone raw material, for example, there is a commercially available silicone base material KE-1734-U manufactured by Shin-Etsu Chemical Co., Ltd. By using such a silicone raw material, the above-mentioned silicone laminate has fire resistance. If it has fire resistance, even if the battery cell overheats abnormally, the possibility of combustion is low.

[0021] The silicone rubber layer (A) and the silicone layer (B) are alternately laminated, and preferably each layer is laminated two or more layers, and a total of four or more layers are laminated. The silicone rubber layer (A) and the silicone layer (B) can be set to a specified thickness, for example, each has a thickness of 1 to 100 mm, and the number of laminated layers can be selected according to the size of the battery cell.

[0022] The thickness of the silicone rubber layer (A) in the lamination direction is 1 to 100 mm, and the thickness of the silicone layer (B) in the lamination direction is 1 to 100 mm. Preferably, the thickness of the silicone layer (B) is in the range of 0.1 to 10 times the thickness of the silicone rubber layer (A). It is easy to manufacture as long as it is within the above range.

[0023] The fire resistance of the above-mentioned silicone laminate is preferably the fire resistance that can maintain its shape when burned by a gas burner for 5 minutes. The gas burner specified in the UL94 standard can be used. As long as it has this degree of fire resistance, even if the battery cell overheats abnormally, the possibility of combustion is low.

[0024] Preferably, the above-mentioned silicone laminate not only has fire resistance but also has a flame retardancy that meets 5VB in the UL94 standard, vertical burning test. The above-mentioned fire-resistant silicone raw material is used to exhibit flame retardancy. The vertical burning test of the UL94 standard is classified from top to bottom as 5VA, 5VB, V-0, V-1, V-2. 5VB is judged by the vertical burning test in the same way as V-0, V-1, V-2, but a gas burner with 10 times the combustion energy is used in the test, and it is considered qualified if the following three conditions are met.

[0025] (1) None of the test pieces burned for more than 60 seconds after being exposed to the flame 5 times.

[0026] (2) No particles falling off (from the test piece).

[0027] (3) No obvious damage was found on the part of each test piece that came into contact with the flame.

[0028] The preferred silicone sponge layer (B1) is an independent foam with a foaming ratio of 1.2 to 3. If the foaming ratio is this, the silicone sponge layer will disappear or foam when the battery cell heats up abnormally, but the heat insulation properties can still be maintained because the fire-resistant rubber layer remains.

[0029] The compressive strength of the organosilicon laminate at 50% compression is preferably 1 to 30 N / mm. 2 Therefore, it can prevent battery deformation and damage when the battery cell overheats abnormally. From this functional perspective, the organosilicon laminate is useful as a buffer material sandwiched between battery cells.

[0030] Preferably, both the silicone rubber layer (A) and the organosilicon layer (B) are peroxide-cured. Peroxide-cured materials offer better processability compared to addition-cured materials.

[0031] Examples of organic peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, (bis(2,4-dichlorobenzoyl) peroxide), p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, di-tert-butyl peroxide, tert-butyl peroxybenzoate, and 1,6-hexanediol-bis-tert-butyl peroxycarbonate. Preferably, the amount of organic peroxide added is 0.1 to 15 parts by weight relative to 100 parts by weight of the silicone rubber component, more preferably 0.2 to 10 parts by weight. If the amount added is too small, the crosslinking reaction cannot be fully carried out, sometimes resulting in decreased hardness, insufficient rubber strength, increased compression set, and other deterioration of physical properties. If the amount added is too large, a large amount of curing agent decomposition products are generated, sometimes leading to increased compression set, other deterioration of physical properties, or increased discoloration of the resulting sheet.

[0032] The following description uses accompanying drawings. In the drawings, the same symbol means the same thing. Figure 1 (A) is a schematic cross-sectional view of a silicone laminate 1 disposed between battery cells 4a and 4b according to one embodiment of the present invention. The silicone laminate 1 is a silicone laminate consisting of a silicone rubber layer (A)2 and a silicone layer (B)3 with a lower hardness than the aforementioned silicone rubber layer. The silicone layer (B)3 is either a silicone sponge layer (B1) or a silicone gel layer (B2). Figure 1(B) is a schematic cross-sectional view of abnormal heating. The silicone rubber layer (A)2 is a high-hardness silicone rubber layer with fire resistance, so it becomes the core material, maintaining fire resistance and heat insulation while preventing deformation between cells 4a and 4b caused by cell expansion.

[0033] Figure 2 (A) is a schematic cross-sectional view of the battery cells 4a and 4b of the comparative example, in which the organosilicon material 5 is disposed. Figure 2 (B) is Figure 2 (A) is a schematic cross-sectional view of an abnormally heated cell. If abnormal heating occurs, for example, battery cell 4b deforms, forming an expansion portion 6, which damages the adjacent battery cell 4a.

[0034] Figure 3 This is a schematic cross-sectional view of a battery in one embodiment of the present invention, in which an organosilicon laminate 1 is arranged between multiple battery cells 4a, 4b... The battery cell has a thermally conductive thin plate (TIM) 8 mounted on a cooling device 7, on which the battery cells 4a, 4b... are arranged, and the organosilicon laminate 1 is arranged between each battery cell 4a, 4b... The upper part is covered by a buffer material plate 9 and a battery casing 10, and wiring 11 is led out from the battery cell 4a.

[0035] Example

[0036] The following description uses examples. The present invention is not limited to these examples. Various parameters were measured using the methods described below.

[0037] <Fire resistance>

[0038] Determine whether the thermal gas burner used in the V-0, V-1, and V-2 vertical burning tests according to UL94 standards maintains its shape after burning for 5 minutes.

[0039] Flame retardancy

[0040] Determine whether it has flame retardancy that meets 5VB in the vertical burning test according to UL94 standard.

[0041] <Hardness>

[0042] The hardness of ASKER A and ASKER C was determined using a rubber hardness tester specified in JIS K 7312.

[0043] <Methods for determining compressive strength>

[0044] ■ Test method: in accordance with ASTM D575-91.

[0045] ■ Sample dimensions: 10mm in length and 10mm in width (thickness is described in the table of the examples).

[0046] ■ Dimensions of upper and lower pressure plates: 30mm vertical, 30mm horizontal, 4mm thick

[0047] ■ Compression speed: 5mm / min

[0048] ■ Compression ratio: 10-50%

[0049] ■Test Methods

[0050] (1) The stacked samples are held in place by upper and lower pressure plates.

[0051] (2) Take the position where the load is felt as the starting position of the measurement and compress it to 10-50%.

[0052] (3) Record the load value for each compression.

[0053] (Examples 1-4, Comparative Examples 1-5)

[0054] 1. Raw material composition

[0055] (1) Silicone rubber layer A

[0056] (a) 100 parts by weight of silicone substrate KE-1734-U manufactured by Shin-Etsu Chemical Co., Ltd., with the addition of 2.5 parts by weight of vulcanizing agent (bis(2,4-dichlorobenzoyl) peroxide), and mixed with two rollers.

[0057] (b) Press the mixture at 120°C for 5 minutes using a press.

[0058] (c) The obtained sheet is subjected to secondary vulcanization at 200°C for 4 hours.

[0059] (2) Organosilicon sponge layer B1

[0060] (a) 100 parts by weight of silicone substrate KE-1734-U manufactured by Shin-Etsu Chemical Co., Ltd., 2.9 parts by weight of vulcanizing agent (bis(2,4-dichlorobenzoyl) peroxide) and 4 parts by weight of foaming agent were added and mixed with two rollers.

[0061] (b) The mixture is pressurized at 150°C for 10 minutes using a press. During this pressing process, the mixture foams (independent foaming) with a foaming ratio of two times.

[0062] (c) The obtained sheet is subjected to secondary vulcanization at 200°C for 4 hours.

[0063] (3) Non-fire-resistant silicone rubber layer

[0064] (a) 100 parts by weight of silicone substrate SH502UA / B manufactured by DOW TORAY, with the addition of 2.5 parts by weight of vulcanizing agent (bis(2,4-dichlorobenzoyl) peroxide), and mixed with two rollers.

[0065] (b) Press the mixture at 120°C for 5 minutes using a press.

[0066] (c) The obtained sheet is subjected to secondary vulcanization at 200°C for 4 hours.

[0067] (d) The hardness of the obtained sheet ASKER A is 50.

[0068] (4) Stacking method

[0069] The surface of the cured thin plate is subjected to corona treatment and then heated at 80°C for 1 hour for bonding.

[0070] Tables 1 and 2 summarize the various physical properties of the obtained laminates.

[0071] Table 1

[0072]

[0073] (Note: The stacking number is 7 layers, A-B1-A-B1-A-B1-A)

[0074] Table 2

[0075]

[0076] (Note: The number of layers in Comparative Examples 3-5 is 7 layers of CDCDCDC)

[0077] As shown in Tables 1 and 2, each embodiment, compared with the comparative examples, was confirmed to be an organosilicon laminate with high fire resistance and compression resistance. These properties also prevent material deformation when the battery abnormally heats up.

[0078] (Examples 5-7)

[0079] 100 parts by weight of a commercially available addition-reaction type silicone gel raw material, namely organopolysiloxane (one of agent A and agent B contains a crosslinking agent, and the other contains a platinum catalyst), were mixed with 2 parts by weight of crosslinking agent and 1 part by weight of platinum catalyst. The mixture was then pressurized at 100°C for 10 minutes. Table 3 summarizes the conditions and results.

[0080] Table 3

[0081]

[0082] (Note: The stacking number is 7 layers, A-B2-A-B2-A-B2-A)

[0083] As shown in Table 3, Examples 5-7 were confirmed to be organosilicon laminates with high fire resistance, flame retardancy, and compression resistance. These properties also prevent material deformation when the battery overheats abnormally.

[0084] Industrial availability

[0085] In addition to being used as a buffer material for battery cells, the organosilicon laminate of the present invention can also be used as a variety of buffer materials.

[0086] Symbol Explanation

[0087] 1- Organosilicon laminate

[0088] 2 – High-hardness silicone rubber layer (A)

[0089] 3 - Low-hardness silicone layer (B)

[0090] 4a, 4b - Battery cells

[0091] 5- Organosilicon materials

[0092] 6 - Expansion section

[0093] 7 - Cooling device

[0094] 8 - Thermally Conductive Thin Sheets (TIM)

[0095] 9 - Thin plate of cushioning material

[0096] 10 - Battery casing

[0097] 11 - Wiring

Claims

1. An organosilicon laminate, characterized in that: It is an organosilicon laminate comprising a silicone rubber layer (A) and an organosilicon layer (B) with a lower hardness than the silicone rubber layer. The silicone layer (B) is at least one layer selected from the silicone sponge layer (B1) and the silicone gel layer (B2); Both the silicone rubber layer (A) and the organosilicon layer (B) are formed of a material that maintains its shape by being ceramized during combustion and becoming a sintered body. The organosilicon laminate is fire-resistant. The silicone rubber layer (A) and the organosilicon layer (B) are alternately stacked, with each layer stacked at least twice, for a total of at least four layers. The silicone rubber layer (A) has an ASKER A hardness of 40 to 80 as measured using a rubber durometer specified in JIS K 7312, and the silicone layer (B) has an ASKER C hardness of 30 to 70 as measured using a rubber durometer specified in JIS K 7312.

2. The organosilicon laminate according to claim 1, wherein, The thickness of the silicone rubber layer (A) in the stacking direction is 1 to 100 mm, and the thickness of the organosilicon layer (B) in the stacking direction is 1 to 100 mm. The thickness of the organosilicon layer (B) is 0.1 to 10 times the thickness of the silicone rubber layer (A).

3. The organosilicon laminate according to claim 1 or 2, wherein, The fire resistance of the organosilicon laminate is the fire resistance in which it maintains its shape when burned in a gas burner for 5 minutes.

4. The organosilicon laminate according to claim 1 or 2, wherein, The organosilicon laminate not only has fire resistance, but also meets the 5VB flame retardancy requirement in the UL94 standard and vertical burning test.

5. The organosilicon laminate according to claim 1 or 2, wherein, The silicone sponge layer (B1) is an independent foam with a foaming ratio of 1.2 to 3 times.

6. The organosilicon laminate according to claim 1 or 2, wherein, The compressive strength of the organosilicon laminate at 50% compression is 1–30 N / mm. 2 .

7. The organosilicon laminate according to claim 1 or 2, wherein, Both the silicone rubber layer (A) and the organosilicon layer (B) are vulcanized with peroxide.

8. A battery, characterized in that, The organosilicon laminate according to any one of claims 1 to 7 is a buffer material sandwiched between battery cells.

9. The battery according to claim 8, wherein, The sides of the silicone rubber layer (A) and the silicone layer (B) of the silicone laminate face the cells of the battery.

Images