Battery Pack Heat Suppression Sheet for Thermal Runaway Integrity
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Solution Overview
Problem
Existing heat transfer suppression sheets for battery packs lose shape retention property, strength, and compression properties at high temperatures during thermal runaway of battery cells, due to the melting and disappearance of the matrix resin.
Innovation Solution
A heat transfer suppression sheet comprising a combination of first and second inorganic fibers and particles with specific glass transition points, along with an organic binder, which forms a network to retain the particles and maintain structural integrity even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a matrix resin is used to retain mineral-based powder and flame retardant in a heat transfer suppression sheet, then the powder retention is improved, but the shape retention property, strength, and compression properties decrease at high temperatures during thermal runaway
Solution Approach 1:
The patent uses a composite structure consisting of inorganic fibers (both crystalline and amorphous), inorganic particles, and organic binder. The inorganic fibers form a heat-resistant skeleton that maintains structural integrity at high temperatures, while the organic binder retains powder particles during normal operation. This composite approach allows the sheet to both retain powder effectively and maintain strength during thermal runaway.
Solution Approach 2:
The patent employs different types of inorganic fibers with different glass transition points (crystalline fibers with Tg ≥ 1000°C and amorphous fibers with Tg < 1000°C) in specific proportions. The amorphous fibers provide flexibility and binding at lower temperatures, while the crystalline fibers provide high-temperature structural support. This local differentiation of material properties resolves the contradiction between powder retention and high-temperature strength.
2Strength
If an organic binder is used to retain inorganic fibers and particles, then the structural integrity at normal temperatures is improved, but the material melts and disappears at high temperatures during thermal runaway
Solution Approach 1:
The patent carefully selects and controls the glass transition points of the inorganic fibers. By using a combination of amorphous fibers (Tg < 1000°C) and crystalline fibers (Tg ≥ 1000°C), the material transitions from a binder-dominated structure at normal temperatures to a fiber-skeleton-dominated structure at high temperatures. This parameter-based design ensures the organic binder performs its binding function at normal temperatures while the inorganic fiber network takes over structural support during thermal runaway, maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sheet maintains excellent shape retention property, strength, and compression properties during thermal runaway, effectively suppressing heat propagation and minimizing damage to adjacent battery cells.
Implementation Method 1
the first inorganic fiber is entangled with the second inorganic fiber to form a network
Implementation Method 2
bound by an organic binder
Implementation Method 3
heat transfer suppression sheet
Data Source
AI summary
A heat transfer suppression sheet contains a first inorganic fiber having a glass transition point of 800° C. or lower and/or a first inorganic particle having a glass transition point of 800° C. or lower; a second inorganic fiber having a glass transition point of 1000° C. or higher; a second inorganic particle having a glass transition point of 1000° C. or higher; and an organic binder.