Nonaqueous Battery Processing Device Melting Metallic Contaminants
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Solution Overview
Problem
Current methods for nonaqueous electrolyte secondary batteries require lengthy heating processes or initial charging to 0.01% to 0.1% of battery capacity, increasing manufacturing costs and inefficiencies in detecting and removing metallic foreign bodies, which can lead to internal short-circuits and voltage drop defects.
Innovation Solution
A processing device that reduces the space between electrodes to bring metallic foreign bodies into contact with the cathode plate at a melting potential, applying surface pressure and optionally heating, to melt and diffuse these foreign bodies before initial charging, thereby preventing short-circuits and voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic foreign bodies are removed by lengthy heating processes (4-10 days at 45°C or 4-7 days at 60-70°C), then reliability is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent applies preliminary action by reducing the space between electrodes before initial charging, forcing metallic foreign bodies into contact with the cathode plate. This preparatory step enables subsequent rapid removal of foreign bodies through brief holding at melting potential, eliminating the need for lengthy heating processes while maintaining battery reliability
Solution Approach 2:
The patent changes the parameter of electrode spacing from normal distance to reduced distance, and changes the electrical state from uncharged to holding at melting potential. These parameter changes enable rapid foreign body removal (within minutes to hours) compared to conventional lengthy heating processes, resolving the contradiction between reliability and manufacturing time
2Reliability
If initial charging is performed to 0.01% to 0.1% of battery capacity, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent performs preliminary action by reducing space between electrodes before initial charging, forcing metallic foreign bodies into contact with the cathode plate. This preliminary step simplifies the initial charging process by enabling foreign body removal at lower charging levels (0.01%-0.1% capacity) rather than requiring full charging cycles, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The patent changes the electrical state parameter from full charging cycles to holding at melting potential achieved through space reduction. This parameter change enables foreign body removal with minimal charging (0.01%-0.1% capacity), eliminating the need for complex charging control systems and reducing overall device complexity
3Productivity
If space between electrodes is reduced to force foreign body contact, then foreign body removal efficiency is improved, but risk of internal short-circuit increases
Solution Approach 1:
The patent applies preliminary action by reducing space between electrodes before initial charging to force metallic foreign bodies into contact with the cathode plate. This preliminary positioning enables subsequent controlled holding at melting potential, which efficiently removes foreign bodies while preventing internal short-circuits through controlled electrical conditions
Solution Approach 2:
The patent changes the spatial parameter from normal electrode spacing to reduced spacing, and changes the electrical parameter to holding at melting potential. These coordinated parameter changes enable high foreign body removal efficiency while controlling the electrical environment to prevent internal short-circuits, resolving the contradiction between productivity 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 method effectively melts and diffuses metallic foreign bodies, reducing the occurrence of internal short-circuits and voltage drop defects, while reducing manufacturing costs and time by eliminating the need for lengthy heating processes and partial charging.
Implementation Method 1
metallic foreign bodies are melted and diffused before initially charging the battery
Implementation Method 2
a space reducing unit for reducing a space present in the electrodes being uncharged, to thereby place the nonaqueous electrolyte secondary battery in a space-reduced state
Implementation Method 3
a holding unit for holding a cathode potential at a melting potential of the metallic foreign bodies for a predetermined period of time in the space-reduced state
Implementation Method 4
metallic foreign bodies are melted and diffused before initially charging the battery
Data Source
AI summary
To melt and diffuse metallic foreign bodies immixed in electrodes of a nonaqueous electrolyte secondary battery before initial charging, electrodes wound with a separator between a cathode plate and an anode plate are placed in a battery case and the battery case is filled with an electrolyte. After the case has been filled, the electrolyte is allowed to permeate into the electrodes. Then, the electrolyte-filled battery is placed in a processing device, and fixed with a surface pressure between at least 0.1 MPa and 5.0 MPa. Thereafter, the cathode potential is adjusted and held for a period of one hour and 35 hours while the battery remains fixed, after which the pre-initial charging process is terminated.