Rubber molded body and battery pack

Abstract

The invention relates to a rubber molded body, which is attached to the outer periphery of more than one lithium ion secondary battery cell having a safety valve or an exhaust hole so as to cover at least the safety valve or the exhaust hole, wherein: the thermal conductivity (measurement temperature: 33 DEG C), of the rubber molded body, measured by a steady state comparative-longitudinal heat flow method in accordance with JIS H7903: 2008 is less than 1.0 W / m.K; the thickness of a portion that covers the safety valve or the exhaust hole is 0.3-10.0 mm; and the hardness of the surface measured by a Type A durometer on the basis of JIS K6253 is 50-90.

Description

technical field [0001] The present invention relates to a rubber molded body obtained by molding and curing a rubber composition, and a battery pack including a lithium ion secondary battery core provided with the rubber molded body. Background technique [0002] In recent years, the demand for lithium ion secondary batteries (hereinafter sometimes referred to as "batteries") has increased. On the other hand, with the development of miniaturization and higher energy density (energy density of 300Wh / kg or more), there is a risk of high temperature due to heat generation depending on the usage method. Therefore, the safety of the cell or battery pack becomes more important. [0003] For example, lithium-ion secondary batteries are at risk of thermal runaway if they are overcharged or overdischarged, or internally or externally short-circuited due to accidental impact. A lithium-ion secondary battery in which thermal runaway occurs generates gas to increase the internal press...

AI Technical Summary

Problems solved by technology

Specifically, for example, in the case of a fireproof sheet made of fiber as described in Patent Document 1, the mesh of the fiber is expanded due to the high pressure of the gas, and in the case of a fireproof sheet made of resin, In the softened state of the resin before reaching the burning state, the fireproof sheet is reduced to a strength that cannot withstand the high pressure and burns through. Therefore, in any case, there is a risk that the fireproof sheet will have a through hole and spray out from the through hole. The high-temperature / high-pressure gas spreads to the components other than the fireproof sheet (such as the packaging housing for the battery) and burns them, and finally spreads to the machines and vehicles equipped with batteries and burns them

[0010] In addition, there is also a risk that air (oxygen) is supplied from the through hole, and the battery itself burns and spreads, causing thermal runaway of the adjacent normal lithium-ion secondary battery.

Images