Dual-Layer Cell Cover for Battery Venting and Thermal Propagation
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Solution Overview
Problem
Existing battery systems face challenges in safely managing thermal runaway of battery cells, which can lead to thermal propagation and potential explosions or fires due to inadequate venting and thermal management, posing risks to adjacent cells.
Innovation Solution
A dual-layer cover system comprising a thicker, heat-resistant first cover sheet with venting openings and a thinner, rupture-prone second cover sheet is used, where the second sheet is disposed between the cells and designed to rupture under high pressure, directing venting gas away from adjacent cells while the first sheet protects and stabilizes the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single thick cover sheet is used to protect battery cells from venting gas stream, then protection reliability is improved, but the cover sheet cannot rupture to allow pressure release during thermal runaway
Solution Approach 1:
The cover sheet is divided into two distinct layers: a first cover sheet made of heat-resistant material for protection, and a second cover sheet designed to rupture for pressure release. This segmentation allows each layer to fulfill its specific function independently, resolving the contradiction between needing protection and needing pressure release.
Solution Approach 2:
The second cover sheet acts as an intermediary element between the battery cell and the external environment. It is positioned to cover the venting exit and serves as a controlled failure point that ruptures under high pressure, mediating between the need for protection and the need for pressure release.
2Object-generated harmful factors
If a single thin cover sheet is used to allow pressure release through rupture, then pressure management is improved, but protection from venting gas stream and particles is insufficient
Solution Approach 1:
The cover system is segmented into two functional layers: the thinner second cover sheet that ruptures for pressure management, and the thicker first cover sheet that provides protection. This segmentation allows the thin sheet to fulfill its pressure release function while the thick sheet provides the necessary protection.
Solution Approach 2:
Different parts of the cover system have different thicknesses and properties: the second cover sheet is thin and rupture-prone for pressure release, while the first cover sheet is thick and heat-resistant for protection. This local differentiation of quality resolves the contradiction between needing thinness for pressure release and thickness for protection.
3Object-generated harmful factors
If venting openings are provided in the cover sheet for pressure release, then pressure management is improved, but particles from venting gas stream can pass through and cause thermal propagation
Solution Approach 1:
The first cover sheet acts as an intermediary protective barrier between the venting exit and the surrounding environment. It is positioned to receive particles from the venting gas stream that pass through the ruptured second cover sheet, preventing these particles from reaching adjacent battery cells and causing thermal propagation.
Solution Approach 2:
The venting gas stream and particles, which are harmful factors, are redirected through the ruptured second cover sheet and onto the first cover sheet. This converts the potentially harmful particle dispersion into a controlled path that protects adjacent cells, as the first cover sheet captures the particles and prevents thermal propagation.
4Temperature
If heat-resistant material is used for the cover sheet, then protection from high temperature is improved, but the cover sheet cannot rupture under pressure
Solution Approach 1:
The heat-resistant property is assigned specifically to the first cover sheet, while the second cover sheet is designed with rupture capability. This segmentation allows the heat-resistant material to provide thermal protection without compromising the pressure release function, as the rupture function is handled by the second sheet.
Solution Approach 2:
Different parts of the cover system have different material properties: the first cover sheet is made of heat-resistant material for thermal protection, while the second cover sheet is made of material that can rupture under pressure. This local differentiation of material quality resolves the contradiction between heat resistance and pressure-induced rupture.
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 dual-layer cover system effectively contains and directs venting gases, preventing thermal propagation and protecting adjacent cells from thermal runaway, enhancing safety and stability in battery systems.
Implementation Method 1
the second cover sheet is adapted to rupture at a section opposite the venting exits by the pressure of the discharged venting gas stream
Data Source
Figure 1
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AI summary
The present disclosure refers to a battery system (100) including: a plurality of battery cells (12), wherein each of the battery cells (12) includes a venting side with a venting exit (14) for discharging a venting gas stream (V), a first cover sheet (20) of a first thickness (t1) covering the plurality of battery cells (12) at the venting sides to protect the battery cells (12) from the venting gas stream (V), the first cover sheet (20) including venting openings (22) aligned with the venting exits (14) of the battery cells (12) for letting the discharged venting gas stream (V) pass through the first cover sheet (20), a second cover sheet (30) of a second thickness (t2) disposed between the first cover sheet (20) and the plurality of battery cells (12), the second cover sheet (30) covering the venting exits (14) of the battery cells (12), wherein the second cover sheet (30) is adapted to rupture at a section (32) opposite the venting exits (14) by the pressure of the discharged venting gas stream (V) exiting the covered venting exit (14), wherein the first thickness (t1) is larger than the second thickness (t2).