Secondary Battery Electrolyte Impregnation via Pressure Control
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Solution Overview
Problem
Existing methods for producing secondary batteries often fail to form a uniform membrane on the wound body due to internal pressure issues during the electrolyte solution impregnation process, leading to potential air penetration and incomplete impregnation.
Innovation Solution
A method involving reducing the internal pressure of the battery case, adding an additive to the electrolyte solution to control gas production, and performing high-temperature aging while maintaining the seal, which allows for uniform impregnation and membrane formation by adjusting internal pressures to match or exceed the saturation vapor pressure of the electrolyte solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the internal pressure of the battery case is increased while pouring the electrolyte solution, then the electrolyte solution is impregnated into the wound body, but air may be pushed into the wound body and penetration of electrolyte solution may be incomplete
Solution Approach 1:
The patent applies preliminary action by reducing the internal pressure of the battery case before pouring the electrolyte solution. This creates a pressure difference that draws the electrolyte solution into the wound body from the start, preventing air entrapment before it occurs. The low pressure environment ensures complete impregnation pathways are established before sealing, allowing uniform membrane formation throughout the entire wound body including axial end portions.
2Reliability
If the internal pressure of the battery case is reduced before pouring the electrolyte solution, then air penetration is prevented and complete impregnation is achieved, but the electrolyte solution may not充分 impregnate into the wound body
Solution Approach 1:
The patent applies parameter changes by carefully controlling the pressure differential between the battery case internal space and external environment during the electrolyte solution pouring process. By maintaining reduced internal pressure during pouring to ensure complete impregnation, then adjusting pressure conditions during subsequent aging processes, the patent achieves both complete electrolyte solution penetration and uniform membrane formation. This dynamic pressure management resolves the contradiction between complete impregnation and uniform membrane formation.
3Manufacturing precision
If an additive is added to generate gas during high-temperature aging to increase internal pressure, then electrolyte solution impregnation is enhanced, but excessive pressure may cause safety issues
Solution Approach 1:
The patent applies periodic action through a multi-stage process: first reducing internal pressure before electrolyte solution pouring, then performing initial charging at atmospheric pressure, and finally conducting controlled high-temperature aging with additive decomposition. This staged approach with distinct pressure conditions at different time periods allows uniform membrane formation during aging while preventing excessive pressure buildup that would compromise safety. The periodic pressure management ensures both manufacturing precision and safety.
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 approach ensures a uniform membrane is formed on the wound body, preventing air penetration and enhancing battery performance by ensuring complete impregnation and stable internal pressures during the charging and aging processes.
Implementation Method 1
by a gas produced through decomposition reaction of the additive, the internal pressure of the battery case in the step for performing the high-temperature aging becomes equal to or higher than a saturation vapor pressure of the electrolyte solution
Implementation Method 2
the electrolyte solution permeates into both axial end portions of the wound body by a capillary phenomenon. Thereby, a sealed space is formed inside the wound body
Data Source
AI summary
The present invention provides a method for producing a secondary battery, capable of forming a uniform membrane on a wound body. Provided is a method including a step for reducing an internal pressure of an exterior, a step for pouring an electrolyte solution (E) into the exterior, a step for sealing the exterior, a step for impregnating the electrolyte solution (E) into the wound body from both axial end portions thereof, a step for performing initial charging of a battery, and a step for performing high-temperature aging of the battery. The additive LPFO is added into the electrolyte solution (E) in an amount such that the internal pressure of the exterior in the step for performing the high-temperature aging becomes equal to or higher than a saturation vapor pressure of the electrolyte solution (E) in the high-temperature aging.