Solid-State Battery Exterior Unit for Self-Discharge Suppression
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Solution Overview
Problem
All-solid-state batteries face issues with self-discharge due to exposure to air components, particularly water, leading to energy consumption and leakage currents, which existing technologies have not adequately addressed.
Innovation Solution
The battery design incorporates an exterior unit with an ion conductivity of 10−2 S/cm or less, forming a barrier that minimizes exposure of active material layers to air, reducing lithium ion deviation and leakage currents, with a conductivity ratio Y of the exterior unit to the solid electrolyte layer set between 0≤Y≤1, and using materials like oxides, alloy oxides, and glass to enhance bonding and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the all-solid-state battery is sealed in a conventional manner, then the battery structure is simple and easy to manufacture, but water enters the sealed interior causing self-discharge and reducing battery reliability
Solution Approach 1:
An exterior unit made of oxide-based solid electrolyte is introduced as an intermediary component between the internal battery components and the external environment. This exterior unit serves as both a structural housing and a functional barrier that prevents water penetration while maintaining ion conductivity for battery operation.
Solution Approach 2:
The exterior unit creates a water-blocking barrier that effectively establishes an inert environment inside the battery, preventing contact between internal components (positive electrode layer, negative electrode layer, solid electrolyte layer) and harmful external substances like water and oxygen.
2Reliability
If the exterior unit has high ion conductivity, then lithium ion transport is efficient, but lithium ions deviate into the exterior unit causing leakage currents and self-discharge
Solution Approach 1:
The ion conductivity of the exterior unit is precisely controlled within a specific range (10^-5 to 10^-3 S/cm). This parameter optimization balances two competing requirements: maintaining sufficient ion conductivity for efficient lithium ion transport during normal operation while preventing excessive ion deviation that would cause leakage currents.
3Length of moving object
If the solid electrolyte layer is made thin to reduce battery thickness, then the battery becomes thinner and more compact, but it becomes difficult to prevent water penetration and self-discharge
Solution Approach 1:
The battery structure is segmented into distinct functional layers: internal layers (positive electrode layer, negative electrode layer, solid electrolyte layer) and an external protective layer (exterior unit). This segmentation allows the thin internal solid electrolyte layer to maintain ion transport efficiency while the separate exterior unit provides dedicated water blocking functionality.
4Reliability
If conventional sealing materials are used, then the manufacturing process is simple, but the sealing material itself contains water that causes self-discharge
Solution Approach 1:
The exterior unit is constructed from oxide-based solid electrolyte materials that are inherently stable and free from water content. This eliminates the water introduction problem associated with conventional organic sealing materials while maintaining ease of manufacture through standard solid-state battery fabrication 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
This configuration significantly improves self-discharge characteristics by reducing energy consumption and leakage currents, maintaining a favorable insulation state and preventing short circuits, thereby enhancing battery reliability.
Implementation Method 1
a solid electrolyte layer arranged between the positive electrode layer and the negative electrode layer and containing a solid electrolyte
Implementation Method 2
the exterior unit has an ion conductivity of 10−2 S/cm or less... reducing lithium ion deviation and leakage currents
Data Source
AI summary
An all-solid-state battery includes a positive electrode layer including a positive electrode current collector layer and a positive electrode active material layer provided on the positive electrode current collector layer, a negative electrode layer including a negative electrode current collector layer and a negative electrode active material layer provided on the negative electrode current collector layer, and a solid electrolyte layer which is arranged between the positive electrode layer and the negative electrode layer and contains a solid electrolyte, wherein the all-solid-state battery includes a power storage unit in which the positive electrode layer and the negative electrode layer face each other with the solid electrolyte layer therebetween and an exterior unit, and wherein the exterior unit has an ion conductivity of 10−2 S/cm or less.