Solid-State Battery Buffer Layer for Heat Suppression
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Solution Overview
Problem
Batteries face challenges in suppressing heat generation due to short circuits, with existing solutions like all-solid-state batteries with PTC layers experiencing resistance loss and instability, particularly when using BaTiO3-based semiconductor PTC materials which are prone to reduction and non-ohmic contacts.
Innovation Solution
Incorporating a buffer layer with a PTC material, a resin, and a first metal (Sn, Cu, Al, Mg, or Zn) in contact with the current collector, forming an ohmic contact to reduce resistance loss and enhance environmental resistance, while protecting the PTC material from degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a PTC layer is disposed between the active material layer and current collector, then heat generation is suppressed, but resistance loss increases and stability deteriorates
Solution Approach 1:
The patent introduces a buffer layer as an intermediary between the PTC layer and current collector. This buffer layer comprises a resin matrix with dispersed conductive particles (metal particles or carbon particles), serving as a mediator that maintains electrical contact while protecting the PTC layer from direct contact with the current collector, thereby preventing reduction and non-ohmic contact issues
Solution Approach 2:
The buffer layer is constructed as a composite material consisting of a resin matrix combined with conductive particles. This composite structure provides both electrical conductivity (through the dispersed particles) and mechanical flexibility (through the resin), while also providing chemical protection to the PTC layer
2Reliability
If BaTiO3-based semiconductor PTC material is used, then PTC characteristics are achieved, but the material is prone to reduction and non-ohmic contacts
Solution Approach 1:
The buffer layer acts as a protective intermediary between the BaTiO3-based PTC material and the current collector. By preventing direct contact, it eliminates the reducing environment that would otherwise cause degradation of the PTC material, thereby maintaining both the PTC characteristics and material stability
Solution Approach 2:
The buffer layer creates a chemically inert environment for the PTC material by isolating it from the current collector and electrode materials that could cause reduction. The resin matrix provides a stable, non-reactive environment that preserves the PTC material's composition and properties
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 interrupts current in case of abnormal heating, achieving high reliability and performance with reduced probabilities of ignition or smoke combustion, and maintaining low resistance loss during normal operation.
Implementation Method 1
the buffer layer includes a PTC material, a resin and a first metal
Data Source
AI summary
A battery of the present disclosure includes a first solid-state battery cell and a buffer layer. The first solid-state battery cell includes a positive electrode, a negative electrode and a solid electrolyte layer located between the positive electrode and the negative electrode. The positive electrode or the negative electrode has a current collector. The buffer layer is in contact with a face of the current collector opposite to the solid electrolyte layer. The buffer layer includes a PTC material, a resin and a first metal. The first metal is at least one selected from the group consisting of Sn, Cu, Al, Mg and Zn.