Electrolyte Injection Apparatus with Negative Pressure and Rotation
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Solution Overview
Problem
Existing methods for injecting electrolytes into secondary batteries, such as lithium-ion batteries, face challenges with slow infiltration due to narrow gaps between electrodes and separators, leading to inefficient filling and potential air bubble entrapment, which affects battery performance and productivity.
Innovation Solution
A method involving a solution injection nozzle inserted into an outer can with a pressure-reducing pad to create negative pressure, combined with rotation of the can to utilize centrifugal force, which pushes out air bubbles and ensures efficient electrolyte infiltration into narrow gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrolyte is injected under reduced pressure to shorten filling time, then the injection rate is improved, but micro air bubbles remain stuck in the gaps and cannot be removed
Solution Approach 1:
The patent applies periodic pressure changes by alternating between reduced pressure (to draw electrolyte in quickly) and atmospheric pressure (to push air bubbles out). This periodic action between suction and non-suction states enables both rapid filling and complete bubble removal, resolving the contradiction between injection rate and filling density.
2Reliability
If the electrolyte is injected slowly to allow complete infiltration into narrow gaps, then the electrolyte filling density is improved, but the injection time increases excessively
Solution Approach 1:
The periodic alternation between reduced pressure state (for rapid electrolyte infiltration) and atmospheric pressure state (for complete gap penetration and bubble removal) enables both high injection rate and complete filling density to be achieved simultaneously, resolving the contradiction between productivity and reliability.
3Reliability
If pressure is applied to decrease air bubble volumes to improve filling density, then the electrolyte filling density is improved, but the injection process becomes more complex
Solution Approach 1:
The patent uses the natural buoyancy of air bubbles combined with periodic pressure changes to achieve bubble removal without complex pressure control systems. The simple switching between reduced pressure and atmospheric pressure states allows the system to self-regulate bubble removal, maintaining filling density while minimizing device complexity.
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 allows for rapid and dense electrolyte filling, reducing filling time and improving battery performance by ensuring complete infiltration and minimizing air bubbles, thus enhancing manufacturing efficiency and cycle characteristics.
Implementation Method 1
making an inside of the outer can into a negative pressure through the pressure reducing pad, and supplying the electrolyte from the solution injection nozzle into the outer can
Implementation Method 2
rotating the outer can with the solution injection nozzle as a rotation center... the electrolyte that has been injected is pushed by a centrifugal force generated by the rotation to flow toward a lateral side of the outer can, thereby forcibly pushing out micro air bubbles
Data Source
AI summary
[Object] It is an object to provide an injection method for injecting an electrolyte and an electrolyte injection apparatus which allow the electrolyte to be injected and filled into an electrode assembly within an outer can with favorable permeation, thereby easily manufacturing an electrolyte secondary battery having favorable cycle characteristics at good yield.[Solution] A solution injection nozzle 10 is inserted into a solution injection hole 101 of an outer can 100 in which an electrode assembly 110 is stored, and the solution injection hole 101 is hermetically sealed by a pressure reducing pad 11 provided so as to surround a periphery of the solution injection nozzle 10. An inside of the outer can 100 is made into a negative pressure through the pressure reducing pad 11, and an electrolyte L is supplied from the solution injection nozzle 10 into the outer can 100. The outer can 100 is rotated with the solution injection nozzle 10 as a rotation center.