Button Cell Swelling Member for Impact-Resistant Can Coupling
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Solution Overview
Problem
Button-type secondary batteries are prone to separation of the upper and lower cans due to external impacts, leading to potential unwinding and damage of the internal electrode assembly.
Innovation Solution
A button-type secondary battery design featuring a swelling member that expands within a space portion formed by the upper and lower cans, absorbing electrolyte to buffer impacts and prevent unwinding of the electrode assembly, with inclined portions and a gasket to enhance coupling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the upper can and lower can are coupled using only friction force and pressure, then the structure is simple, but the cans separate when external impact is applied
Solution Approach 1:
A swelling member is pre-installed in the lower can to provide beforehand cushioning against external impacts. When impact occurs, the swelling member expands to absorb the shock, preventing can separation. This resolves the contradiction by adding a simple cushioning element that significantly improves coupling stability without complex mechanisms.
Solution Approach 2:
The swelling member changes its volume parameter in response to electrolyte absorption, expanding from a compact state to a swollen state. This parameter change enables the cushioning function dynamically - small in normal operation, large during impact absorption - improving reliability while maintaining simple structure.
2Reliability
If the upper can and lower can are tightly coupled, then coupling stability improves, but the electrode assembly may be damaged by external impact
Solution Approach 1:
The swelling member provides beforehand cushioning between the electrode assembly and the can walls. When external impact occurs, this pre-positioned cushioning element absorbs the shock before it reaches the electrode assembly, protecting it from damage while allowing tight can coupling for stability.
Solution Approach 2:
The swelling member acts as an intermediary between the external impact force and the electrode assembly. It absorbs and dissipates the impact energy, preventing direct transmission to the fragile electrode assembly while allowing the cans to remain tightly coupled.
3Reliability
If the swelling member is expanded too much, then impact buffering improves, but the internal space is insufficient for electrolyte injection
Solution Approach 1:
The swelling member's volume parameter changes dynamically based on electrolyte absorption. In the initial state, it occupies minimal space allowing adequate room for electrolyte injection. Upon impact, it expands to provide buffering. This dynamic parameter change resolves the space contradiction.
Solution Approach 2:
The swelling member transitions from a static compact form to a dynamic expanded form in response to environmental conditions (electrolyte absorption). This dynamic behavior allows the system to have both sufficient initial space and adequate impact buffering capability at different times.
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 swelling member effectively absorbs and dissipates external impacts, improving durability by preventing electrode assembly damage and maintaining structural integrity, while also enhancing sealing performance and efficiently utilizing internal space.
Implementation Method 1
when the electrolyte is injected, the swelling member absorbs the electrolyte to be expanded in volume within the space portion
Implementation Method 2
the swelling member absorbs the electrolyte to be expanded in volume within the space portion
Data Source
AI summary
A button-type secondary battery includes an electrode assembly in which a negative electrode, a separator, and a positive electrode are layered wound in a state of being layered; a lower can in which the electrode assembly is mounted, and a space portion is defined as a surplus space in addition to a space in which the electrode assembly is mounted; an upper can coupled to the lower can to close the lower can in a state in which the electrode assembly is mounted in the lower can, and an electrolyte is injected; and a swelling member mounted in the lower can in a state of being coupled to an outer surface of the electrode assembly. When the electrolyte is injected, the swelling member absorbs the electrolyte to be expanded in volume within the space portion.