Button Cell Terminal Structure for Short-Circuit and Pressure Relief
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Solution Overview
Problem
Ultra-small rechargeable batteries used in wearable devices are prone to short circuits, terminal damage, and explosion risks due to assembly errors, pressure, and unintended temperature and pressure increases.
Innovation Solution
A rechargeable battery design featuring an electrode assembly with a separator between electrodes, a case with a cap plate and terminal plate having a protrusion with a curved and inclined surface, and a thermal-fusion layer for insulation bonding, which helps prevent short circuits, terminal damage, and explosion risks by dispersing stress and venting gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery size is reduced to ultra-small for wearable devices, then the battery can be mounted on wearable devices, but short circuit may occur between electrode terminals due to assembly errors
Solution Approach 1:
The terminal plate is segmented into a flange portion and a protrusion portion, where the flange portion covers the through-hole to prevent short circuits while the protrusion portion provides electrical connection. This segmentation allows the terminal structure to simultaneously achieve compact size and short circuit prevention in ultra-small batteries.
2Volume of moving object
If the battery size is reduced to ultra-small for wearable devices, then the battery can be mounted on wearable devices, but damage to electrode terminal due to pressure may occur
Solution Approach 1:
The protrusion portion of the terminal plate features a curved surface instead of a sharp edge. This curvature design distributes mechanical stress evenly across the electrode terminal contact area, preventing localized damage and enhancing terminal strength in ultra-small battery configurations.
3Temperature
If temperature and pressure are unintentionally increased inside the battery, then thermal expansion and gas generation may occur, but explosion risk increases
Solution Approach 1:
The cap plate is designed with a through-hole positioned to align with the protrusion portion of the terminal plate before thermal events occur. This preliminary structural arrangement creates a predetermined venting pathway that activates automatically during thermal expansion or gas generation, preventing pressure buildup and explosion risks.
4Reliability
If the flange portion covers the through-hole to prevent short circuits, then short circuit prevention is achieved, but the structure becomes more complex
Solution Approach 1:
The flange portion and protrusion portion are integrally formed as a single terminal plate structure rather than separate components. This merging reduces assembly complexity and manufacturing steps while maintaining the short circuit prevention function, as the flange naturally covers the through-hole in the cap plate during assembly.
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 design effectively suppresses short circuits, terminal damage, and explosion risks, ensuring the safety and reliability of ultra-small rechargeable batteries in wearable devices.
Implementation Method 1
The thermal-fusion layer may melt at a predetermined temperature.
Data Source
AI summary
A rechargeable battery includes: an electrode assembly including a first electrode, a second electrode, and a separator between the first electrode and the second electrode; a case configured to be connected to the first electrode to accommodate the electrode assembly, and including an opening to receive the electrode assembly; a cap plate configured to be coupled with the case to cover an outer area of the opening, and including a through-hole to expose a central area of the opening; and a terminal plate configured to be connected to the second electrode and to be insulation-bonded to the cap plate, and including a flange portion covering the through-hole, and a protrusion penetrating the through-hole from the flange portion.