Solid Battery Buffer Film for Uniform Lithium Deposition
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Solution Overview
Problem
Fully solid batteries face issues with non-uniform lithium precipitation leading to internal short circuits and capacity deterioration due to lithium oxide formation, which is difficult to prevent, especially with sulfide solid electrolytes that are prone to breakage under pressure.
Innovation Solution
Incorporating a buffer film with a base substrate and a buffer layer composed of particulates and a binder, which provides resilience and stress relief, and using a module structure with upper and lower plates to apply pressure uniformly, preventing non-uniform lithium precipitation and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pressure is applied to the fully solid battery to improve contact between components, then electrical conductivity and ion transfer efficiency are improved, but non-uniform lithium precipitation occurs leading to internal short circuits and capacity deterioration
Solution Approach 1:
A buffer film is introduced between the negative electrode plate and the external pressure source to distribute applied pressure uniformly across the battery components. This cushioning layer prevents localized high-pressure zones that would cause non-uniform lithium precipitation, while still maintaining sufficient contact for efficient ion transfer and electrical conductivity.
Solution Approach 2:
The buffer film serves as an intermediary layer that mediates between the external pressure and the battery components. It transforms the concentrated pressure into distributed pressure, enabling uniform lithium precipitation while maintaining the necessary contact pressure for ion transfer efficiency and electrical conductivity.
2Use of energy by moving object
If sulfide solid electrolyte is used to achieve high ionic conductivity, then charging and discharging performance is improved, but the electrolyte becomes prone to breakage under pressure causing internal short circuits
Solution Approach 1:
The buffer film provides beforehand cushioning to the sulfide solid electrolyte layer, distributing mechanical stress uniformly and preventing localized breakage. This allows the electrolyte to maintain its high ionic conductivity while being protected from pressure-induced cracking that would cause internal short circuits.
Solution Approach 2:
The buffer film acts as a flexible protective layer that conforms to the battery components while distributing pressure. This thin film structure protects the brittle sulfide solid electrolyte from mechanical failure while maintaining the close contact necessary for high ionic conductivity.
3Reliability
If uniform pressure is applied to prevent non-uniform lithium precipitation, then battery reliability is improved, but complex module structures with upper and lower plates are required
Solution Approach 1:
The pressure distribution function is segmented from the main battery structure and incorporated into a separate buffer film component. This allows the buffer film to handle the complex task of uniform pressure distribution while the rest of the battery structure remains simple and straightforward.
Solution Approach 2:
The buffer film performs multiple functions simultaneously: it distributes pressure uniformly, protects the solid electrolyte from breakage, maintains contact between components, and prevents non-uniform lithium precipitation. This multi-functionality reduces the need for additional complex structural elements.
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 ensures uniform lithium precipitation and dissociation, preventing internal short circuits and capacity loss, while also enhancing the durability of the solid electrolyte layer and improving the cycle-life of the battery.
Implementation Method 1
a buffer layer formed by attaching a first particulate formed on at least one surface of the base substrate to provide resilience and a second particulate that relieves stress by a binder
Implementation Method 2
The solid electrolyte layer may be a medium that conducts lithium ions
Implementation Method 3
lithium ions are deposited to a metal on the negative electrode plate to accumulate lithium, i.e., lithium metal is deposited on the negative electrode plate, during charging
Data Source
AI summary
A fully solid battery includes a positive electrode plate, a solid electrolyte layer disposed on one side of the positive electrode plate, a negative electrode plate disposed on one side of the solid electrolyte layer, and a buffer film disposed on one side of the negative electrode plate. The buffer film includes a base substrate and a buffer layer on at least one surface of the base substrate. The buffer layer includes a first particulate that provides resilience, a second particulate that relieves stress, and a binder.