Secondary Battery Insulating Sheet Series Connection
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Solution Overview
Problem
Secondary batteries face challenges in achieving high voltage and preventing short circuits due to ion conduction between electrode groups, particularly when using liquid electrolytes, which can lead to reduced output density and increased risk of short circuits.
Innovation Solution
Incorporating an insulating sheet between electrode groups and connecting it to a container member to prevent ion conduction and short circuits, while allowing for series connection of electrode groups, thereby isolating the electrolytes and maintaining high ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolyte is used in the battery, then high ion conductivity is achieved, but short circuit between electrode groups occurs due to ion conduction
Solution Approach 1:
The battery is divided into multiple independent battery modules, each containing a single electrode group surrounded by its own sealant layer. This segmentation prevents ion conduction between electrode groups while maintaining liquid electrolyte within each module, thereby eliminating short circuit risk while preserving high ion conductivity.
Solution Approach 2:
A gel-type sealant is introduced as an intermediary substance between adjacent battery modules. This sealant layer acts as a barrier that prevents direct contact between liquid electrolytes of different electrode groups, blocking ion conduction pathways while allowing each module to maintain its liquid electrolyte environment for high ion conductivity.
2Reliability
If solid electrolyte is used to prevent short circuit, then ion conduction between electrode groups is blocked, but ion conductivity decreases to 1/10 to 1/100 of liquid electrolyte
Solution Approach 1:
The patent changes the physical state parameter of the sealant from solid (in conventional designs) to gel-type. This gel sealant maintains the short-circuit prevention function while having minimal impact on the ion conductivity of the liquid electrolyte, thereby preserving high output density unlike solid electrolytes that reduce conductivity to 1/10 to 1/100 of liquid electrolyte levels.
3Power
If gel electrolyte is used to maintain high ion conductivity, then satisfactory output density is obtained, but the gel electrolyte softens easily causing contact between electrode groups and short circuit
Solution Approach 1:
Each electrode group is enclosed in its own sealed battery module with a gel-type sealant layer. This segmentation prevents the softened gel electrolyte from contacting adjacent electrode groups, maintaining short-circuit prevention even when the gel electrolyte softens at elevated temperatures, while still allowing high ion conductivity within each module.
Solution Approach 2:
The gel-type sealant serves as an intermediary barrier between battery modules. Even when this sealant softens, it maintains its structural integrity as a barrier layer, preventing contact between gel electrolytes of different modules and thus preventing short circuits while allowing high ion conductivity to be maintained within each module.
4Power
If electrode groups are connected in series inside a battery, then high voltage is obtained, but the device size increases
Solution Approach 1:
Multiple electrode groups are nested within a single battery casing, with each electrode group contained in its own compact battery module. This nested arrangement allows series connection for high voltage output while minimizing the overall battery volume by efficiently utilizing the internal space through compact modular design.
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 effectively prevents short circuits and maintains high ion conductivity, allowing for efficient series connection of electrode groups without compromising battery performance, even with liquid electrolytes.
Implementation Method 1
a voltage to be obtained from a unit cell is about 2.3 to 3.7 V. Therefore, unit cells need to be connected in series and controlled to obtain a high voltage, so that the whole device is increased in size.
Implementation Method 2
If a gel electrolyte which is a semisolid liquid electrolyte is used, it is expected that ion conductivity will be high and satisfactory output density of the battery will be obtained.
Data Source
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AI summary
In one approach, a secondary battery (10) includes, electrode groups (21), an insulating sheet (26), and a container member (12). The insulating sheet (26) is disposed between the electrode groups (21). At least part of the insulating sheet (26) is joined to the container member (12). The container member (12) covers the outside of a stack (11) having the electrode groups (21) and the insulating sheet (26).