Battery Electrode Surface Fillers for Nail Penetration Heat Suppression
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Solution Overview
Problem
Existing electrodes for non-aqueous electrolyte secondary batteries face issues with increased resistance and heat generation during nail penetration tests, which compromise battery safety.
Innovation Solution
Incorporating an aggregate of filler particles containing boron oxide, potassium pyrosulfate, or compounds with alkali metals and Br on the electrode surface, which transform into a liquid phase at specific temperatures to form a coating film that acts as a resistor, reducing short circuit current and ion conductivity, thereby suppressing temperature and resistance increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a coating layer containing functional material or an intermediate layer of polyphosphate is disposed on the electrode surface, then heat generation is suppressed, but resistance increases
Solution Approach 1:
The filler particles undergo phase transition from solid to liquid at specific temperatures (180°C to 650°C) during nail penetration tests. This phase transition allows the particles to transform into a liquid phase that forms a coating film, providing heat suppression through the phase change process while maintaining lower resistance compared to conventional coating layers.
Solution Approach 2:
The electrode uses a composite structure combining filler particles (containing boron oxide, potassium pyrosulfate, and compounds with alkali metals or Br) with the active material layer. This composite approach enables the filler particles to provide thermal protection through phase transition while the overall structure maintains acceptable resistance characteristics, resolving the contradiction between heat suppression and resistance.
2Reliability
If a coating layer or intermediate layer is added to suppress heat generation, then safety is improved, but device complexity increases
Solution Approach 1:
The filler particles are incorporated directly onto the surface of the active material layer, merging the safety function with the existing electrode structure. This integration approach provides heat suppression and safety improvement without adding separate coating layers or intermediate layers, thereby avoiding increased device complexity.
Solution Approach 2:
The filler particles on the electrode surface automatically undergo phase transition and form protective coating films when exposed to high temperatures during nail penetration tests. This self-activating mechanism provides safety improvement without requiring external control systems or complex structural modifications, maintaining simplicity in device design.
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 and resistance in nail penetration tests by forming a flame-retardant coating and maintaining smooth ion flow, enhancing battery safety.
Implementation Method 1
a transformation point of the filler particle at which the filler particle is transformed from a solid phase into a liquid phase or is thermally decomposed is in a range of 180° C. to 650° C.
Implementation Method 2
a transformation point of the filler particle at which the filler particle is transformed from a solid phase into a liquid phase or is thermally decomposed
Implementation Method 3
these layers become resistors and resistance of the battery is increased
Data Source
AI summary
This electrode for nonaqueous electrolyte secondary batteries is provided with a collector, an active material layer that is formed on the collector, and an assembly of filler particles, said assembly being present on the surface of the active material layer. The filler particles contain at least one of boron oxide, potassium pyrosulfate and a compound containing an alkali metal or Br, while having a transformation point, at which the filler particles undergo a transformation from a solid phase to a liquid phase or a thermal decomposition, within the range of from 180° C. to 650° C. The compound containing an alkali metal or Br contains at least one of a borate, a silicate, a carbonate, a hydrogen carbonate, a citrate or an aromatic compound.