Positive Electrode Intermediate Layer for Internal Short-Circuit Heat Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing nonaqueous electrolyte secondary batteries face challenges in effectively suppressing heat generation during internal short circuits, as current techniques do not adequately manage thermal conduction and heat diffusion.
Innovation Solution
A positive electrode with an intermediate layer containing insulating inorganic particles, highly thermal conductive particles, a thermoplastic resin, and polyvinylidene fluoride is used, where the inorganic particles comprise at least 50% of the intermediate layer's mass, enhancing thermal conduction and adhesion to prevent heat buildup during internal short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the intermediate layer contains highly thermal conductive particles, then heat diffusion is improved, but adhesion between the intermediate layer and mixture layer may be compromised
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different components within the intermediate layer. Insulating inorganic particles provide structural integrity and adhesion, while highly thermal conductive particles are distributed throughout to provide heat diffusion pathways. The binder resin locally bonds particles together and to the mixture layer, ensuring adhesion is maintained despite the presence of thermal conductive particles.
Solution Approach 2:
The composite structure combines materials with complementary properties: insulating particles for structural stability, thermal conductive particles for heat diffusion, and binder resin for adhesion. This multi-material composition resolves the contradiction between heat diffusion and adhesion by distributing functions across different material phases.
2Reliability
If the content of inorganic particles is increased to 50% by mass or more, then thermal conduction and structural integrity are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple particle types (insulating inorganic particles and highly thermal conductive particles) and binder resin into a single slurry composition that can be applied in one coating step. This combining approach maintains the required 50% or more inorganic particle content for structural integrity while simplifying manufacturing by avoiding multiple separate application processes.
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 solution effectively suppresses heat generation and temperature increase during internal short circuits by improving thermal conduction and ensuring the structural integrity of the intermediate layer, thereby preventing battery damage.
Implementation Method 1
by using the highly thermal conductive particles having a thermal conductivity of 50 W/mK or more and the thermoplastic resin which melts at the time of occurrence of abnormalities, such as internal short circuit, and adheres closely to the surfaces of the highly thermal conductive particles to join the particles, heat generated at the short-circuit point can be quickly diffused
Implementation Method 2
the thermoplastic resin which melts at the time of occurrence of abnormalities, such as internal short circuit, and adheres closely to the surfaces of the highly thermal conductive particles to join the particles
Implementation Method 3
an intermediate layer which is interposed between the positive electrode current collector and the positive electrode mixture layer... insulating inorganic particles having a thermal conductivity of less than 50 W/mK
Data Source
AI summary
A positive electrode as an example of an embodiment includes a positive electrode current collector, a positive electrode mixture layer which is disposed on at least one surface side of the positive electrode current collector, and an intermediate layer which is interposed between the positive electrode current collector and the positive electrode mixture layer. The intermediate layer contains insulating inorganic particles having a thermal conductivity of less than 50 W/mK, highly thermal conductive particles having a thermal conductivity of 50 W/mK or more, a thermoplastic resin, and polyvinylidene fluoride. The content of the inorganic particles is 50% by mass or more relative to the mass of the intermediate layer.