Secondary Battery Cap Plate Wrinkle Buffer for Shock Resistance
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Solution Overview
Problem
Conventional secondary batteries are prone to damage from external shocks due to the thin rupture section in the depression of the cap plate, which can lead to premature failure even under minor external impacts, compromising the battery's reliability.
Innovation Solution
The formation of wrinkles between the rupture section and the periphery of the depression in the cap plate or can, which acts as a buffer to absorb external shocks, preventing damage from sources other than internal pressure while maintaining the depression's inherent function of releasing gas during overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the depression is formed with a thin rupture section to enable gas discharge during overcharging, then the pressure relief function is improved, but the structural strength and shock resistance deteriorate
Solution Approach 1:
Wrinkles are formed in the cap plate at the depression location before the battery is assembled. These pre-formed wrinkles create a cushioning effect that absorbs external shocks, protecting the thin rupture section from damage while maintaining its pressure relief function. The wrinkles act as a shock-absorbing buffer that prevents direct transmission of external forces to the vulnerable rupture section.
Solution Approach 2:
The cap plate is designed with a depression that includes a thin rupture section, utilizing the flexibility of thin metal structures. The rupture section is intentionally made thin (70-100 micrometers) to allow it to rupture at predetermined locations when internal pressure exceeds safety thresholds, while the surrounding flexible cap plate structure with wrinkles provides shock absorption.
2Reliability
If the rupture section thickness is reduced to 70-100 micrometers for effective pressure relief, then the gas discharge capability is improved, but the susceptibility to external shock damage increases
Solution Approach 1:
Wrinkles are formed in the cap plate at the depression location before the battery is assembled. These pre-formed wrinkles create a cushioning effect that absorbs external shocks, protecting the thin rupture section from damage while maintaining its pressure relief function. The wrinkles act as a shock-absorbing buffer that prevents direct transmission of external forces to the vulnerable rupture section.
Solution Approach 2:
The cap plate exhibits different local properties: the rupture section is made thin (70-100 micrometers) to facilitate easy rupture and gas discharge, while other portions of the cap plate maintain normal thickness for structural strength. The wrinkles are localized at the depression area to provide targeted shock absorption where the thin rupture section is most vulnerable.
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 wrinkles effectively absorb external shocks, enhancing the battery's shock-proof properties and preventing rupture of the depression section, thereby improving the reliability and durability of the secondary battery.
Implementation Method 1
forming wrinkles between a rupture section and a periphery of a depression formed in a cap plate or a can, and thus prevent damage of the depression due causes other than the internal gas pressure of the battery
Data Source
AI summary
A secondary battery has a depression having a thickness less than that of other portions of the periphery of a cap plate or a can. The depression includes a rupture section having a smallest thickness in the depression and further includes wrinkles between the rupture section and the periphery of the depression. Furthermore, the secondary battery is manufactured by a method including: a first coining step of forming the thickness of some portions of the cap plate or the can to be less than that of other peripheral portions thereof; a second coining step of forming wrinkles on the periphery of some portions where the first coining has been performed; and a third coining step of forming a rupture section having the smallest thickness in the depression on an inner side of the wrinkles.