Stacked Solid-State Battery Side-Electrode Layout for Short-Circuit Isolation
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Solution Overview
Problem
Batteries face challenges in achieving high capacity density and reliability due to the risk of short circuits at thinner unit cell ends, which complicates voltage monitoring and overcharging/overdischarging prevention.
Innovation Solution
A battery design where unit cells are stacked with one electrode layer protruding more than the other, featuring conductive members and an insulating member to expose extraction electrodes, allowing for voltage monitoring and preventing short circuits while reducing unit cell thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the unit cell is reduced to increase capacity density, then the capacity density is improved, but the reliability deteriorates due to increased risk of short circuit at the end surface
Solution Approach 1:
The end surface of the unit cell is segmented into multiple regions by providing a plurality of protrusions and depressions. This segmentation allows the extraction electrodes to be positioned at specific protrusions while maintaining insulating barriers at other regions, enabling voltage monitoring without compromising reliability even in thin unit cells.
Solution Approach 2:
An insulating member is introduced as an intermediary substance to cover the side surface of the unit cell and prevent short circuits between adjacent electrodes. This insulating layer allows the unit cell thickness to be reduced while maintaining reliability by providing electrical isolation at the vulnerable end surface regions.
2Reliability
If extraction electrodes are connected to each unit cell for voltage monitoring, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Multiple extraction electrodes are merged and connected to a common connection electrode. This combining approach allows voltage monitoring of multiple unit cells through a single connection point, reducing the complexity of electrode connections while maintaining the ability to monitor each unit cell's voltage for reliability.
Solution Approach 2:
The connection electrode serves multiple functions: it acts as an extraction electrode for voltage monitoring, provides a common connection point for multiple unit cells, and maintains electrical contact with the electrode layer. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure.
3Measurement precision
If conductive members are provided on protrusions for extraction electrode connection, then the voltage monitoring capability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The protrusions and depressions are formed in advance during the unit cell manufacturing process, creating predetermined positions for extraction electrodes. This preliminary structuring allows extraction electrodes to be connected at specific locations without requiring high-precision positioning during assembly, as the contact positions are pre-defined by the protrusion geometry.
Data Source
AI summary
A battery includes a power generation element that includes a plurality of unit cells each including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer, the unit cells are stacked in a direction normal to a main surface, in a side surface of the power generation element, one electrode layer of the positive electrode layer and the negative electrode layer in each of the unit cells protrudes more than the other electrode layer such that depressions and projections are provided, each of the depressions includes a first inclination surface that is an end surface of the other electrode layer, and the battery further includes: one or more conductive members in contact with a corresponding one of the projections; an insulating member that covers the side surface; and one or more extraction electrodes that are in contact with the one or more conductive members.