Battery Cell Casing Bead Structure for Swelling Resistance
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Solution Overview
Problem
Prismatic battery cells face safety and durability issues due to swelling forces caused by lithium-ion insertion/extraction, leading to deformation and capacity fading, especially with increased electrode sheets, requiring stronger structural components to maintain safety and durability throughout the battery's life.
Innovation Solution
Incorporating stamped beads and recesses on the casing plates of battery cells during the metal stamping process increases the flexural stiffness of the top cover, reducing outward deformation caused by internal gas pressure without altering existing design parameters, thereby enhancing the structural integrity and resilience of the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat metal plate of uniform thickness is used for the top cover, then the manufacturing process is simple, but the plate deforms significantly and changes shape under swelling force
Solution Approach 1:
The patent applies curvature to the top cover plate by forming beads (protrusions) and recesses (indentations) on its surface. These curved features increase the plate's flexural stiffness and resistance to deformation under swelling force, while being formed through stamping processes that are compatible with existing manufacturing capabilities.
Solution Approach 2:
The patent introduces localized structural features (beads and recesses) at specific locations on the top cover rather than uniformly thickening the entire plate. This allows targeted reinforcement in areas subject to highest stress while maintaining manufacturing efficiency and controlling overall plate weight.
2Quantity of substance
If the number of electrode sheets is increased, then the battery capacity is improved, but the swelling force increases causing faster capacity fading
Solution Approach 1:
The patent incorporates beads and recesses in the top cover design before the battery undergoes swelling during operation. These pre-formed structural features act as cushioning elements that accommodate and distribute the swelling force generated by lithium-ion insertion/extraction, preventing excessive stress concentration that would lead to deformation and capacity fading.
3Strength
If thicker plates are used for the top cover, then the structural strength is improved, but the deformation and volume change increase
Solution Approach 1:
The patent uses curved bead and recess features to increase the plate's moment of inertia and flexural stiffness without increasing its thickness or volume. The geometric curvature provides structural strength while maintaining a compact form factor.
Solution Approach 2:
Instead of increasing strength by adding thickness in the vertical dimension, the patent introduces structural complexity in the horizontal dimension through beads and recesses. This dimensional transition allows strength enhancement without volumetric increase.
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 added stamped bead and recess structure enhances the flexural stiffness of the battery cell's top cover, reducing deformation and improving the structural resilience, ensuring the battery's safety and durability without increasing costs or modifying design parameters.
Implementation Method 1
the plate has at least one stamped bead protruding towards the inner space of the casing, which crosses a centerline of the width of the plate and forms a recess facing away from the inner space of the casing
Data Source
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AI summary
A casing (10) for a battery cell (100) has at least one plate (1) made of sheet metal closing an inner space (2) of the casing (10) for housing a stack of electrodes. The plate (1) has a length (L), a width (W) and a thickness (t) such that a slenderness ratio of the plate W/t is greater than 10. The plate (1) has at least one stamped bead (3) protruding towards the inner space (2) of the casing (10), which crosses a centerline (C) of the width (W) of the plate (1) and forms a recess (4) facing away from the inner space (2) of the casing (100), the recess (4) having an average width value Q measured at the centerline (C) of the width (W) of the plate (1), characterised in that the average width value Q is greater than 0.3t and less than 3t.