Electrochemical Cell Compression Structure for Electrode Volume Change
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Solution Overview
Problem
Existing electrochemical cells with rigid packaging face issues of volume expansion and contraction during charging and discharging, leading to non-uniform mechanical stress and potential degradation due to local pressure variations, which are not effectively addressed by conventional compression devices.
Innovation Solution
An electrochemical cell with a compression device comprising a deformable return element and a metal shell that adjusts to volume changes, ensuring constant pressure and uniform contact between electrodes, using elastically deformable fins or accordion structures to accommodate expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid metal housing is used to contain electrodes, then structural strength and sealing are improved, but the housing cannot accommodate volume expansion/contraction of electrodes during charging and discharging, leading to mechanical stress and potential degradation
Solution Approach 1:
The rigid housing is segmented into a fixed outer shell and a movable inner structure (compression plate assembly) that can independently move to accommodate electrode volume changes. This segmentation allows the housing to maintain overall structural strength while enabling local adaptation through the movable compression plate.
Solution Approach 2:
The compression plate is designed to be movable rather than fixed, allowing it to dynamically adjust its position and apply varying compression forces in response to electrode expansion and contraction during charging and discharging cycles. This dynamic mechanism resolves the contradiction between rigid housing and volume adaptability.
2Ease of manufacture
If compression devices are applied at module or battery pack level, then pressure application is simplified, but uniform pressure distribution across all electrodes cannot be achieved, leading to non-uniform mechanical stress and potential degradation
Solution Approach 1:
A compression plate is introduced as an intermediary element between the electrodes and the housing. This plate distributes the compression force uniformly across all electrode surfaces through its large contact area, ensuring even pressure distribution while maintaining ease of implementation through a simple mechanical design.
3Ease of operation
If local pressure is applied to hold electrodes in position, then assembly is facilitated, but non-uniform pressure distribution occurs between compressed and non-compressed areas, leading to non-uniform ageing and degradation
Solution Approach 1:
The compression plate creates an equipotential pressure distribution across all electrode surfaces, ensuring that every point on the electrode assembly experiences the same compression force. This eliminates the non-uniform pressure fields that would otherwise cause differential ageing and degradation, while maintaining simple assembly through the plate's straightforward mechanical design.
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 provides consistent mechanical support and contact between electrodes, enhancing the lifespan and performance of the electrochemical cell by maintaining uniform pressure regardless of the cell's state of charge or age.
Implementation Method 1
at least one return element (6) that is at least partly elastically deformable configured to be deformed between a first configuration and a second configuration based on a volume of the plurality of electrodes
Data Source
AI summary
An electrochemical cell for an electrical energy storage device, in particular intended for a motor vehicle, comprising a plurality of electrodes (3) and a compression device (4) adapted to the variations in volume of the plurality of electrodes (3), the compression device (4) comprising a casing (5) and an at least partially elastically deformable return element (6) allowing the constant exertion of a suitable compression on the plurality of electrodes (3) in order to keep the various elements thereof in contact with one another and thus allow more homogeneous operation of the cell.