CN-117693425-B - Thermal insulation pad for battery system

Abstract

The invention relates to a thermal insulation mat (1) for insulating adjacent battery cells (2), in particular prismatic battery cells, in a battery system, comprising an elastically deformable base plate (7) made of a fiber-elastomer composite structure, wherein a defined number of ribs (8) are provided on both main surfaces of the base plate (7), which ribs extend parallel to each other and spaced apart from each other in the transverse direction on the main surfaces of the base plate (7), wherein the rib arrangement of the two main surfaces is surrounded by a surrounding frame (10), and wherein a gap (11) is present between the ribs (8) and the frame (10), wherein the fiber-elastomer composite structure of the base plate (7) is formed by an elastomer matrix with at least one intermediate layer embedded therein made of mineral fibers, and wherein the thermal insulation mat is simultaneously capable of compensating for system-inherent volume changes of the battery cells due to chemical aging of the battery cell assembly and to periodic expansion and contraction of the battery cells upon charging and discharging.

Inventors

• H. WALTER
• M - Margaret
• T. Fritz
• A. Tomaszpolsky
• J. Ullerman
• T. Yu bule

Assignees

• 欧瑞康摩擦系统(德国)有限公司

Dates

Publication Date

20260505

Application Date

20220713

Priority Date

20210716

Claims (15)

1. 1. Thermal insulation mat (1) for insulation between adjacent battery cells (2) in a battery system, having an elastically deformable base plate (7) consisting of a fiber-elastomer composite structure, on both main surfaces of which base plate (7) a number of ribs (8) are provided, which extend parallel to each other and spaced apart from each other in the transverse direction over the main surfaces of the base plate (7), the rib arrangement of the two main surfaces being surrounded by a surrounding frame (10), and a gap (11) being present between the ribs (8) and the frame (10), the fiber-elastomer composite structure of the base plate (7) being formed by an elastomer matrix together with at least one intermediate layer consisting of mineral fibers, the height of the surrounding frame (10) being greater than the height of the ribs (8) and the deformation resistance of the surrounding frame (10) being greater than the deformation resistance of the ribs (8) in the state in which no compressive load is applied.
2. 2. Thermal insulation pad (1) according to claim 1, characterized in that the elastomeric material is selected from the group consisting of silicone elastomers, styrene-butadiene rubber, acrylonitrile-butadiene rubber, natural rubber, butyl rubber, isobutylene-isoprene rubber and isoprene rubber, and polyurethane.
3. 3. Thermal insulation pad (1) according to claim 2, characterized in that the elastomer is selected from the group consisting of silicone elastomers and polyurethanes.
4. 4. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the mineral fibres for the intermediate layer are selected from glass fibres, basalt fibres, silicate fibres and oxide ceramic fibres.
5. 5. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the width of the surrounding frame (10) is larger than the width of the ribs (8).
6. 6. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the width of the space (9) between two adjacent ribs (8) is at least 1.5 to 2 times the width of the ribs (8).
7. 7. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the ribs (8) and surrounding frame (10) are formed of an elastomeric material.
8. 8. A thermal insulation pad according to claim 7, characterized in that the ribs (8) or the ribs (8) and surrounding frame (10) are formed of the same elastomeric material as the base plate (7).
9. 9. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the substrate (7) has two or more intermediate layers made of mineral fibers.
10. 10. Thermal insulation pad (1) according to claim 9, characterized in that an elastomer material is provided as adhesive between two intermediate layers made of mineral fibers.
11. 11. Thermal insulation pad (1) according to claim 1 or 2, characterized in that a metal foil reflecting infrared radiation is provided in the substrate (7).
12. 12. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the base plate (7), ribs (8) and surrounding frame (10) are one-piece members.
13. 13. Thermal insulation pad (1) according to claim 1 or 2, characterized in that in the ribs (8) there are provided laterally extending interruptions (16) and/or in the surrounding frame (10) at least one outlet for the out-gassing of the reaction gases.
14. 14. Thermal insulation pad (1) according to claim 1 or 2, characterized in that the ribs (8) of the two main surfaces of the base plate (7) are arranged offset from each other.
15. 15. Use of a thermal insulation pad according to any one of claims 1 to 14 in a battery system having prismatic battery cells.

Description

Thermal insulation pad for battery system Technical Field The present invention relates to a thermal insulation mat for a battery system, in particular a lithium ion battery system, which is arranged between individual battery cells of the battery system in order to prevent the propagation of overheating to neighboring battery cells in the event of a failure of a battery cell, for example due to overheating of the battery cell. The thermal insulation pad according to the present invention can be advantageously used for a battery system such as a battery system used in the field of electric automobiles. Background Battery systems are generally composed of a plurality of battery cells in order to achieve the necessary high energy density. Here, a certain number of battery cells are combined into one module and the respective modules are combined into one cell stack and electrically connected to each other. The battery system obtained is placed in a hermetically closed housing to protect it from external influences. In principle, battery types can be classified into cylindrical battery cells, prismatic battery cells, and pouch-type battery cells. Prismatic cells have a square shape with a rigid housing (also called a cell cup), whereas pouch cells, also called coffee pouch cells, have a flexible outer shell made of film. The invention relates in particular to a battery system with rechargeable batteries, so-called secondary battery cells, also called secondary batteries. A battery system commonly used in the field of electric automobiles is a lithium ion battery-based battery system, for example. In order to ensure the operational safety of a battery system composed of a plurality of individual battery cells, in the event of a single fire of one battery cell, for example, due to overheating, it is necessary to prevent the fire of the battery cell from spreading to adjacent battery cells, even to burn out the entire battery system (thermal runaway). When the battery cells fire, a high temperature of 600 ℃ or higher occurs within only a few seconds. In order to prevent overheating and prevent fire from spreading to adjacent battery cells, measures to prevent the temperature of adjacent battery cells from rising above a critical value must be taken. In lithium ion batteries, the decisive factors of the critical temperature values are in particular the electrolyte or the composition of the electrolyte and the triggering range for switching off the separator. Lithium ion battery cells use liquid electrolytes that include components that boiling around 100 ℃ and are flammable. Therefore, the cell temperature must be maintained below the boiling point to prevent pressure rise in the hermetically sealed cell. If the internal pressure of the cell is too high, the safety valve opens, the gas formed escapes, and the highly reactive electrolyte typically ignites immediately under such conditions. Turning off the separator is a safety measure for inhibiting ion transport and interrupting the current by closing the micropores of the separator when the critical temperature is exceeded. Shut-off separators are known which consist of a laminated structure comprising two polymer films, where the polymers have different melting points. For example, a typical shut-off separator is constructed of a polyethylene/polypropylene laminate structure, the polyethylene having a melting point of 120 ℃ and the polypropylene having a melting point of 170 ℃. If the melting point of the lower melting polymer film, here polyethylene, is exceeded, the polymer film melts and closes the pores of the higher melting polymer film, here polypropylene. From the foregoing, it can be seen that the cell temperature must be maintained below 150 ℃, especially below 120 ℃, and preferably below 100 ℃ as much as possible to prevent overheating of the cell and the safety risks associated therewith. It is known that thermal insulation means must be provided between adjacent cells to prevent the adjacent cells from warming above a critical temperature and thereby causing the cells to fire. In addition to thermal insulation, other aspects need to be considered for safe operation of the battery system. Thus, the thermal insulation structure should also function as an electrical insulator at the same time to achieve electrical insulation of the battery cells or of the potential differences across the battery cell housing between the battery cells of the module. Another important aspect in the design of lithium ion battery systems is the system-dependent volume change (also known as swelling) of the battery cells. The reason for this is, on the one hand, continuous cell swelling due to chemical aging of the cell assembly and, on the other hand, periodic swelling and swelling of the cells during charging and discharging. In particular, in the production of battery systems based on prismatic battery cells, the volume changes inherent in such systems must be taken into