US-20260128421-A1 - SILICA AEROGEL POWDER USED IN THERMAL INSULATOR FOR BATTERY PACK AND THERMAL INSULATOR FOR BATTERY PACK

Abstract

When a silica aerogel powder used in a thermal insulator for a battery pack is measured by a nitrogen adsorption amount measurement method, a specific surface area and a pore volume at a relative pressure of 0.99 measured based on an adsorption isotherm that is obtained are 550 m 2 /g or more, and 3.5 mL/g or more and 5.0 mL/g or less, respectively, and when a [mL/g] is a pore volume at a relative pressure of 0.93, b [mL/g] is a pore volume at a relative pressure of 0.965, and c [mL/g] is a pore volume at a relative pressure of 0.99, the following conditions (i) and (ii) are satisfied: 0 ≤ ( a / c × 100 ) ≤ 50 ( i ) 50 ≤ ( b / c × 100 ) < 1 ⁢ 0 ⁢ 0 ( ii )

Inventors

• Shigeaki Takamatsu
• Shota Hayashi
• Koichiro TACHIBANA
• Ryota UEOKA
• Shusaku Tsutsumi

Assignees

• SUMITOMO RIKO COMPANY LIMITED
• TIEM FACTORY INC.

Dates

Publication Date

20260507

Application Date

20260105

Priority Date

20240325

Claims (10)

1. 1 . A silica aerogel powder used in a thermal insulator for a battery pack, characterized in that, when the silica aerogel powder is measured by a nitrogen adsorption amount measurement method, a specific surface area and a pore volume at a relative pressure of 0.99 measured based on an adsorption isotherm that is obtained are 550 m 2 /g or more, and 3.5 mL/g or more and 5.0 mL/g or less, respectively, and when a [mL/g] is a pore volume at a relative pressure of 0.93, b [mL/g] is a pore volume at a relative pressure of 0.965, and c [mL/g] is a pore volume at a relative pressure of 0.99, the following conditions (i) and (ii) are satisfied: 0 ≤ ( a / c × 100 ) ≤ 50 ( i ) 50 ≤ ( b / c × 100 ) < 1 ⁢ 0 ⁢ 0 . ( ii )
2. 2 . A thermal insulator for a battery pack, the thermal insulator comprising the silica aerogel powder according to claim 1 .
3. 3 . The thermal insulator for a battery pack according to claim 2 , the thermal insulator comprising a press-molded component of a composition containing the silica aerogel powder.
4. 4 . The thermal insulator for a battery pack according to claim 2 , the thermal insulator further comprising at least one selected from among infrared shielding particles, inorganic fibers, and dispersants.
5. 5 . The thermal insulator for a battery pack according to claim 2 , wherein the silica aerogel powder has an average particle size of 30 μm or more and 150 μm or less.
6. 6 . The thermal insulator for a battery pack according to claim 2 , wherein the thermal insulator is used in a vehicle.
7. 7 . A thermal insulator for a battery pack, the thermal insulator including a silica aerogel, characterized in that, when the silica aerogel is measured by a nitrogen adsorption amount measurement method, a specific surface area and a pore volume at a relative pressure of 0.99 measured based on an adsorption isotherm that is obtained are 550 m 2 /g or more, and 3.5 mL/g or more and 5.0 mL/g or less, respectively, and when a [mL/g] is a pore volume at a relative pressure of 0.93, b [mL/g] is a pore volume at a relative pressure of 0.965, and c [mL/g] is a pore volume at a relative pressure of 0.99, the following conditions (i) and (ii) are satisfied: 0 ≤ ( a / c × 100 ) ≤ 50 ( i ) 50 ≤ ( b / c × 100 ) < 1 ⁢ 0 ⁢ 0 . ( ii )
8. 8 . The thermal insulator for a battery pack according to claim 7 , the thermal insulator further comprising at least one selected from among infrared shielding particles and dispersants.
9. 9 . The thermal insulator for a battery pack according to claim 7 , wherein the thermal insulator is used in a vehicle.
10. 10 . The thermal insulator for a battery pack according to claim 7 , the thermal insulator further comprising a fiber material.

Description

CLAIM FOR PRIORITY This application is a Continuation of PCT/JP2025/009356 filed Mar. 12, 2025, the contents of which is expressly incorporated by reference herein in its entirety. TECHNICAL FIELD The present disclosure relates to a thermal insulator disposed between adjacent battery cells in a battery pack in which a plurality of battery cells is accommodated, and specifically to a thermal insulator using a silica aerogel powder or silica aerogel. BACKGROUND ART A battery pack in which a plurality of battery cells is accommodated is mounted in hybrid electric vehicles and battery electric vehicles. In the battery pack, a battery module formed by laminating a plurality of battery cells is accommodated in a casing in a state in which the battery module is fixed by fastening members from both sides in a lamination direction. A thermal insulator is disposed between adjacent battery cells in order to suppress heat transfer and thermal runaway when battery cells overheat abnormally. The battery cells expand and contract as a result of charging and discharging. Therefore, it is preferable for the thermal insulator disposed between the battery cells to be able to deform in response to the expansion and contraction of the battery cells while maintaining its thermal insulation. More specifically, when the battery cell is charged and expands, the thickness of the thermal insulator is reduced due to the compressive force, and at the same time, it is necessary to generate a reaction force equal to or above a certain value to energize the battery cell and avoid positional displacement of the battery cell. In addition, when the battery cell is discharged and contracts (returns to its original thickness), the thickness of the thermal insulator also needs to be returned. Silica aerogels having low thermal conductivity are known as thermal insulator materials. For example, Patent Document 1 describes an aerogel powder with excellent flexibility and resistance to breakage under compressive force, the aerogel powder being made of an aerogel that is a hydrolysis condensation product of a silane compound. The silane compound as a raw material satisfies 0≤Qx≤70, 30≤Tx≤100, 0≤Dx<30 (where Qx+Tx+Dx=100), when Qx, Tx, and Dx are mass percentages of a tetrafunctional silane compound, a trifunctional silane compound, and a bifunctional silane compound, respectively. Patent Document 2 describes a silica aerogel as an example of an aerogel used in an aerogel composite. Paragraphs [0023] and [0025] of Patent Document 2 describe, as physical and structural properties of the aerogel, (a) an average pore diameter of 2 nm to 100 nm, (b) a porosity of 80% or more, (c) a surface area of 20 m2/g or more, (d) a pore volume of 2.0 mL/g or more, and the like, as determined by a nitrogen porosity measurement test. RELATED ART DOCUMENTS Patent Documents Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-165387 (JP 2021-165387 A)Patent Document 2: Japanese Unexamined Patent Application Publication No. 2023-27128 (JP 2023-27128 A) SUMMARY OF THE INVENTION Problem to be Solved by the Invention Patent Document 1 describes the use of a predetermined silane compound as a raw material in order to improve the flexibility and resistance to breakage (a property of being difficult to break) of the aerogel powder under compressive force. However, Patent Document 1 does not describe imparting compression recovery to a silica aerogel, that is, imparting the ability to deform under load and return to its original state upon unloading. In addition, Patent Document 1 describes that, when pores are approximated as a tube and the inner diameter of the tube is approximated as a circle, the pore portion of the aerogel is in the range of 5 nm or more and 100 nm or less. In addition, Patent Document 1 describes that the inner diameter of the tube is equal to or smaller than the mean free path of elemental molecules constituting air under atmospheric pressure. However, Patent Document 1 simply describes the size of the pore portion (pores) of the aerogel but does not provide any technical concept focusing on and specifying the pore structure to achieve desired properties. Similarly, in Patent Document 2, as a general structure of the aerogel, the values of the surface area and the pore volume are described, and there is no examination of the pore structure. The present disclosure has been made in view of the above circumstances, and provides a silica aerogel powder having excellent thermal insulation and compression recovery and used in a thermal insulator for a battery pack, and a thermal insulator for a battery pack using the same. The present disclosure also provides a thermal insulator for a battery pack using a silica aerogel having excellent thermal insulation and compression recovery. Means for Solving the Problem (1) In order to solve the above issue, a silica aerogel powder of the present disclosure is a silica aerogel powder used in a