Hydraulic Pressurizing Plates for Uniform Pouch Cell Formation Pressure
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Solution Overview
Problem
Conventional apparatuses for charging and discharging pouch-type secondary batteries experience pressure non-uniformity at both ends during the formation process, leading to quality degradation issues like lithium precipitation, due to thickness deviations in the electrical field direction.
Innovation Solution
A pressurized channel system comprising a pair of pressurizing plates with exterior parts that expand hydraulically, including a heating pad and silicone pads, and a fluid supplying part to maintain uniform pressure, with the exterior parts positioned ⅔ or more from the center towards the ends of the pressurizing plates to compensate for pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pressurized plates are used without exterior parts, then the structure is simple, but pressure non-uniformity occurs at both ends of the secondary battery during formation process
Solution Approach 1:
The pressurized plate is segmented into a body part and multiple exterior parts positioned at different locations. The exterior parts are selectively expanded using independent fluid supplying channels to compensate for pressure non-uniformity at specific regions, particularly at both ends of the secondary battery.
Solution Approach 2:
Different regions of the pressurized plate are given different properties through the exterior parts. The exterior parts can be selectively expanded to provide localized pressure compensation where needed, while the body part maintains overall pressurization.
2Manufacturing precision
If exterior parts are positioned at the ends of pressurizing plates, then pressure drop at both ends is compensated, but the structure becomes more complex
Solution Approach 1:
The exterior parts are integrated with the body part to form a unified pressurized plate structure. The fluid supplying part provides centralized control for expanding multiple exterior parts through a coordinated system of fluid channels.
Solution Approach 2:
Hydraulic pressure is used to expand the exterior parts of the pressurized plate. Fluid supplying channels deliver pressurized fluid to selectively expand rubber or elastic materials in the exterior parts, enabling precise pressure control at different locations.
3Manufacturing precision
If uniform pressure is applied across the entire pressurized plate, then the structure is simple, but thickness deviation in electrical field direction causes pressure non-uniformity at battery ends
Solution Approach 1:
The system uses the known thickness deviation characteristics of the secondary battery to pre-position and pre-expand the exterior parts. This compensatory expansion creates feedback that counteracts the pressure non-uniformity caused by battery thickness variation, achieving uniform pressure distribution.
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 solution effectively improves pressure uniformity at both ends of the secondary battery during the formation process, preventing quality degradation and lithium precipitation by thermally expanding the exterior parts to match the body part's pressure profile.
Implementation Method 1
each exterior part including a tube configured to be expanded by hydraulic pressure
Implementation Method 2
thermally expanding the exterior parts to match the body part's pressure profile
Data Source
AI summary
A pressurizing channel includes a pair of pressurizing plates disposable on opposite sides of a secondary battery with the secondary battery interposed therebetween. Each pressurizing plate includes a body part and an exterior part connected to opposite ends of the body part, each exterior part including a tube inside that is expandable by hydraulic pressure. An apparatus for charging and discharging a secondary battery having a plurality of pressurizing channels is also provided.