Cylindrical Electrode Restraint for Battery Expansion Control
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Solution Overview
Problem
Existing power storage devices face reliability issues due to the expansion of the negative electrode over long-term cycles, leading to potential damage and capacity retention problems.
Innovation Solution
A power storage device design that includes a cylindrical metal restraint member covering the side peripheral surface of the electrode assembly, which deforms radially when a predetermined force is applied, thereby accommodating the expansion of the electrode assembly and maintaining the integrity of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid restraint member is used to prevent electrode assembly expansion, then structural stability is improved, but reliability deteriorates due to inability to accommodate long-term expansion
Solution Approach 1:
The restraint member is designed with dynamic characteristics, allowing it to deform elastically in the radial direction when subjected to expansion forces from the electrode assembly. This dynamic response enables the restraint member to adapt to long-term expansion while maintaining structural stability, thereby improving reliability without sacrificing structural integrity.
2Reliability
If the restraint member is made deformable to accommodate electrode expansion, then reliability is improved, but structural stability worsens due to potential excessive deformation
Solution Approach 1:
The physical parameters of the restraint member are carefully controlled, including its elastic modulus, thickness, and radial strength, to ensure it deforms within acceptable limits. The restraint member is designed to deform only when a predetermined force threshold is exceeded, maintaining structural stability under normal operating conditions while accommodating expansion during long-term cycling.
3Strength
If a metal restraint member is used to prevent crushing of electrolyte space, then device integrity is improved, but adaptability worsens due to inability to accommodate volume changes
Solution Approach 1:
The metal restraint member incorporates dynamic deformation capability in the radial direction, allowing it to adapt to volume changes of the electrode assembly during charging and discharging cycles. This dynamic behavior enables the restraint member to maintain device integrity by preventing excessive crushing while simultaneously adapting to normal expansion and contraction, thereby improving both strength and adaptability.
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 use of a deformable metal restraint member enhances the reliability of the power storage device by preventing the crushing of the electrolyte space and maintaining capacity retention over multiple cycles.
Implementation Method 1
The restraint member is deformed in a radial direction of the electrode assembly when a predetermined force or more is received from the electrode assembly
Data Source
AI summary
A power storage device includes an electrode assembly in which a positive electrode, a negative electrode, and a separator are wound, a restraint member having a cylindrical shape, including metal, and covering a side peripheral surface of the electrode assembly, and an exterior can that accommodates the electrode assembly covered with the restraint member and an electrolyte solution. The restraint member is deformed in a radial direction of the electrode assembly when a predetermined force or more is received from the electrode assembly.