Wound Electrode Assembly Holes for Better Electrolyte Penetration
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Solution Overview
Problem
As the size of the wound electrode assembly increases, it becomes difficult for the electrolyte solution to penetrate effectively into the assembly, leading to inefficient power storage device performance.
Innovation Solution
Incorporating a first hole in the wound electrode assembly that extends from the outer peripheral surface toward the winding axis, allowing the electrolyte solution to permeate more easily, along with a groove in the case to facilitate electrolyte solution injection and gas discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the wound electrode assembly is increased, then the power storage capacity is improved, but the electrolyte solution penetration into the assembly deteriorates
Solution Approach 1:
The patent divides the wound electrode assembly structure by introducing first holes that extend from the outer peripheral surface toward the winding axis, and second holes through the separator. This segmentation creates multiple penetration pathways for the electrolyte solution, allowing it to effectively reach the inner regions of large-sized assemblies while maintaining good electrolyte distribution throughout the entire structure.
2Ease of operation
If holes are formed in the wound electrode assembly to improve electrolyte penetration, then the electrolyte distribution is improved, but the risk of short circuit between electrodes increases
Solution Approach 1:
The patent applies local quality by making the separator regions within the second holes have different properties than the surrounding separator material. Specifically, the separator portions at the hole locations are removed or thinned to create openings, while the rest of the separator maintains its insulating properties. This localized modification allows electrolyte penetration without compromising the overall short circuit prevention capability of the separator.
Solution Approach 2:
The separator acts as an intermediary element that mediates between the need for electrolyte penetration and short circuit prevention. By strategically removing separator material only at specific hole locations while maintaining it elsewhere, the separator enables electrolyte flow paths while continuing to provide electrical insulation between positive and negative electrodes in the regions where it remains intact.
3Ease of operation
If the separator opening area is increased to improve electrolyte flow, then the electrolyte penetration is improved, but the short circuit risk increases
Solution Approach 1:
The patent segments the hole structure into multiple components: first holes extending from the outer surface and second holes through the separator. This segmentation allows the electrolyte to flow through a distributed network of small openings rather than requiring large individual openings, thereby maintaining good electrolyte flow while minimizing the opening area at any single location and reducing short circuit risk.
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 configuration enables better penetration and distribution of the electrolyte solution within the wound electrode assembly, enhancing the power storage device's performance and reducing the risk of short circuits.
Implementation Method 1
A first hole extending in a direction from the outer peripheral surface toward the winding axis is formed in the wound electrode assembly... it is possible to allow the electrolyte solution to permeate into the wound electrode assembly from the outer peripheral surface side of the wound electrode assembly through the first hole
Implementation Method 2
A groove extending in the predetermined direction is formed in the inner peripheral surface. The groove faces the first hole... it is possible to allow the electrolyte solution and gas to be exchanged between the groove and the first hole
Data Source
AI summary
A power storage device includes: a wound electrode assembly with a winding axis extending in a predetermined direction, the wound electrode assembly being formed of a stack wound spirally around the winding axis, the stack including a positive electrode in a strip shape, a negative electrode in a strip shape, and a separator in a strip shape; and a case containing an electrolyte solution and the wound electrode assembly. The wound electrode assembly has an outer peripheral surface facing the case. A first hole extending in a direction from the outer peripheral surface toward the winding axis is formed in the wound electrode assembly.