Battery Cell Thickness Ratio for Thermal Runaway Pressure Relief
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Solution Overview
Problem
Existing battery cells face challenges in ensuring safety, particularly during thermal runaway, due to high gas production rates and heat release power, leading to structural deformation and potential explosion, especially when the volumetric energy density is high.
Innovation Solution
Adjusting the relationship between the volumetric energy density and minimum thickness of the battery cell to ensure it falls within a specific range (E≥600 Wh/L, 6 Wh/(L·mm)≤E/T≤100 Wh/(L·mm), incorporating a pressure relief mechanism, and optimizing the connection between the shell and end cover through welding to enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the volumetric energy density of the battery cell is increased to improve energy storage capacity, then the energy density is improved, but the gas production rate and heat release power during thermal runaway increase, leading to higher safety risks and structural deformation
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative relationships between volumetric energy density E and minimum thickness T (6 Wh/(L·mm)≤E/T≤100 Wh/(L·mm)). This parameter optimization allows the battery cell to achieve high energy density (E≥600 Wh/L) while maintaining safety by controlling the thickness to prevent excessive gas pressure buildup and structural deformation during thermal runaway events.
2Stability of the object's composition
If the minimum thickness of the battery cell is increased to reduce deformation during thermal runaway, then the structural stability is improved, but the volumetric energy density decreases
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by defining the relationship 6 Wh/(L·mm)≤E/T≤100 Wh/(L·mm). This allows determination of the minimum thickness T based on the volumetric energy density E, ensuring structural stability while maximizing energy density. The parameter change approach finds the optimal balance point between these two conflicting requirements.
Solution Approach 2:
The patent applies dynamics by making the minimum thickness T a dynamic parameter that adapts to different volumetric energy density requirements. Rather than using a fixed thickness value, the thickness is determined based on the specific energy density target, allowing the design to optimize both structural stability and energy density for different application scenarios.
3Quantity of substance
If the minimum thickness of the battery cell is decreased to improve volumetric energy density, then the energy density is improved, but the risk of cracking and structural deformation increases during thermal runaway
Solution Approach 1:
The patent uses parameter changes to establish the minimum thickness T as a function of volumetric energy density E through the relationship 6 Wh/(L·mm)≤E/T≤100 Wh/(L·mm). This parameter optimization ensures that the battery cell maintains sufficient structural strength and resistance to cracking while achieving high volumetric energy density, by preventing the thickness from being reduced below the safety threshold.
Data Source
AI summary
Embodiments of the present application provide a battery cell, a battery, and an electrical apparatus. For the battery cell of the present application, the volumetric energy density of the battery cell is E, the minimum thickness of the battery cell is T, and T and E meet: E≥600 Wh/L, and 6 Wh/(L·mm)≤E/T≤100 Wh/(L·mm). For the battery cell provided in the present application, the high-energy-density battery cell has a high gas production rate and heat release power when thermal runaway occurs, and therefore, the minimum thickness of the battery cell is adjusted to meet requirements of the high-energy battery cell, thereby ensuring the safety of the battery cell.