Positive Electrode Intermediate Layer for Battery Heat and Gas Suppression
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Solution Overview
Problem
Secondary batteries, such as lithium ion batteries, face challenges in suppressing heat generation during internal short circuits and gas generation during high temperature storage, with existing technologies offering limited effectiveness in these areas.
Innovation Solution
A positive electrode with an intermediate layer composed of metal compound particles, including sulfates, hydroxides, and oxides of alkaline earth or alkali metals, is used to mitigate heat and gas generation. This layer separates the current collector from the active material, reducing redox reactions and capturing fluoric acid to prevent gas formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an intermediate layer including aluminum oxide is formed between the current collector and mixture layer, then heat generation during normal operation is suppressed, but heat generation during internal short circuit cannot be sufficiently suppressed
Solution Approach 1:
The patent changes the chemical composition parameters of the intermediate layer by incorporating metal compounds (sulfates, hydroxides, or oxides of alkaline earth metals or alkali metals) in addition to aluminum oxide. This compositional parameter change enables the intermediate layer to suppress heat generation during internal short circuits more effectively than conventional aluminum oxide-only layers.
Solution Approach 2:
The patent creates a composite intermediate layer material combining aluminum oxide with metal compounds (sulfates, hydroxides, or oxides of alkaline earth metals or alkali metals). This composite structure provides both the heat suppression capability during normal operation and enhanced protection during internal short circuits, resolving the contradiction between normal operation performance and short circuit protection.
2Object-affected harmful factors
If conventional intermediate layers are used, then current collectability is maintained, but gas generation during high temperature storage cannot be sufficiently suppressed
Solution Approach 1:
The patent modifies the chemical composition of the intermediate layer by adding metal compounds (sulfates, hydroxides, or oxides of alkaline earth metals or alkali metals) to the aluminum oxide base. This compositional change provides chemical stability during high temperature storage, suppressing gas generation while maintaining current collectability.
Solution Approach 2:
The metal compounds in the intermediate layer act as sacrificial protective elements that can chemically interact with potential gas-generating species during high temperature storage, preventing gas formation while maintaining the structural integrity and electrical conductivity of the intermediate layer.
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 proposed solution effectively suppresses heat generation during internal short circuits and gas generation during high temperature storage, enhancing the safety and performance of secondary batteries.
Implementation Method 1
suppress the heat generated by the redox reaction between a positive electrode active material and an aluminum current collector
Implementation Method 2
capturing fluoric acid to prevent gas formation
Data Source
AI summary
This positive electrode includes a current collector, an intermediate layer which is formed at least on one surface of the current collector, and a composite material layer which is formed on the intermediate layer. The intermediate layer includes metal compound particles, a conductive material, and a binding material. The metal compound particles comprise at least one selected from a sulfated oxide, hydroxide, or oxide of alkali earth metal or alkali metal.