Lithium Ion Battery Rapid Replenishment via Third Electrode
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Solution Overview
Problem
Lithium ion secondary batteries experience a decline in battery capacity over time due to lithium consumption from side reactions during charge/discharge cycles, and existing solutions for capacity recovery using a third electrode as a lithium ion supply source require an excessively long time for replenishment.
Innovation Solution
A lithium ion secondary battery design featuring a wound electrode assembly with a third electrode outside the assembly, a porous insulating film, and an electroconductive battery case, allowing for rapid lithium ion replenishment by facilitating the movement of lithium ions into the battery through the insulating film and battery case connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a third electrode is disposed outside the wound electrode assembly, then lithium ion replenishment can be achieved, but the replenishment time becomes excessively long
Solution Approach 1:
The third electrode is positioned to face multiple surfaces of the wound electrode assembly (outer peripheral surface and end surfaces) rather than a single location, creating multi-directional lithium ion supply paths that significantly reduce replenishment time
Solution Approach 2:
A porous insulating film is introduced as an intermediary between the third electrode and the wound electrode assembly, allowing lithium ions to pass through while providing structural support and controlled ion transport pathways
2Speed
If the third electrode is positioned close to the wound electrode assembly, then replenishment speed increases, but direct contact causes short circuits
Solution Approach 1:
The porous insulating film serves as a mediator that physically separates the third electrode from the wound electrode assembly, preventing direct contact and short circuits while maintaining close proximity for rapid lithium ion transport
Solution Approach 2:
The porous insulating film provides a three-dimensional network of channels that facilitate rapid lithium ion diffusion while maintaining electrical insulation, combining the benefits of close proximity with safe separation
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
Enables efficient and rapid lithium ion replenishment, reducing the time required for capacity recovery and enhancing the battery's performance by minimizing the distance between the third electrode and the wound electrode assembly.
Implementation Method 1
a porous insulating film that is disposed between the wound electrode assembly and the third electrode and that is formed from a material usable as a separator in a battery
Implementation Method 2
the third electrode has a portion facing, across the insulating film, an outer surface of the negative electrode that constitutes the outermost circumference of the negative electrode of the wound electrode assembly
Data Source
AI summary
Provided is a lithium ion secondary battery that enables lithium ion replenishment in a short period of time. The lithium ion secondary battery disclosed herein is provided with a wound electrode assembly in which a long sheet-shaped positive electrode and a long sheet-shaped negative electrode are wound such that the negative electrode is positioned on the outer side of the positive electrode; a third electrode that is disposed outside the wound electrode assembly and that has an Li supply source capable of supplying lithium ion; and a porous insulating film that is disposed between the wound electrode assembly and the third electrode and that is formed from a material usable as a separator in a battery. In this lithium ion secondary battery, the third electrode has a portion facing, across the insulating film, an outer surface of the negative electrode that constitutes the outermost circumference of the negative electrode of the wound electrode assembly, and has a portion facing, across the insulating film, a wound electrode assembly open end face that communicates with the interior of the wound electrode assembly and is an end face of the wound electrode assembly along the direction of the winding axis.