Battery Cell Shell Melting Point for Thermal Runaway Resistance
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Solution Overview
Problem
The challenge in battery technology is to enhance the safety of battery cells, particularly during thermal runaway, where the high-temperature and high-pressure substances released can cause the shell to melt, potentially leading to safety accidents.
Innovation Solution
The proposed solution involves a battery cell design where the shell's melting point is optimized based on the nickel content in the positive electrode active material. For 0.1≤M≤0.65, the melting point N is set to at least (50M+500)° C., and for 0.65<M<1, N is set to at least (950M+500)° C., to prevent shell melting during thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the nickel content in the positive electrode active material is increased to improve energy density, then the energy density is improved, but the heat generated during thermal runaway increases and the shell melting risk increases
Solution Approach 1:
The patent changes the parameter of shell melting point N based on the nickel content parameter M in the positive electrode active material. By establishing a dynamic relationship where N≥(50M+500)°C for 0.1≤M≤0.65 and N≥(950M+500)°C for 0.65<M<1, the shell's thermal resistance is optimized to match the heat generation characteristics of different nickel-content electrodes, resolving the contradiction between energy density and thermal safety.
2Reliability
If the shell melting point is increased to prevent shell melting during thermal runaway, then the safety is improved, but the material selection and design complexity increases
Solution Approach 1:
The patent simplifies material selection by establishing a clear parameter relationship between nickel content M and required melting point N. This quantitative guideline (N≥(50M+500)°C or N≥(950M+500)°C depending on M range) transforms a complex material selection problem into a straightforward calculation, reducing design complexity while ensuring safety.
3Reliability
If the shell wall thickness is increased to prevent shell melting, then the safety is improved, but the battery cell volume increases and energy density decreases
Solution Approach 1:
Instead of universally increasing wall thickness, the patent changes the parameter of shell melting point N based on electrode composition. This allows the use of thinner walls by compensating with higher melting point materials selected according to the specific nickel content M, thereby maintaining safety while minimizing volume increase and preserving energy density.
Data Source
AI summary
Embodiments of the present application provide a battery cell, a battery, and an electrical device. The battery cell includes a shell and a positive electrode plate. The melting point of the shell is N. The positive electrode plate is accommodated within the shell and includes a positive electrode active material, which includes lithium nickel cobalt manganese oxide. A weight of a nickel element in the lithium nickel cobalt manganese oxide is G1, and the sum of weights of a nickel element, a cobalt element, and a manganese element is G2. A value of G1/G2 is M. M and N meet: 0.1≤M≤0.65, N≥(50M+500)° C.; or M and N meet: 0.65<M<1, N≥(950M+500)° C. The present application reduces the risk of the melting of the shell during the thermal runaway of the battery cell and improve the safety.