Rechargeable Battery Current Interrupt Module
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Solution Overview
Problem
Conventional rechargeable batteries face issues with overcharging, leading to increased surface temperature, voltage spikes, expansion, and reduced lifespan, particularly in rectangular batteries due to difficulties in interrupting current.
Innovation Solution
A rechargeable battery design incorporating a current interrupt module with a sub-plate, middle plate, and insulating members, where the convex member protrudes to interrupt current when internal pressure increases, preventing overcharge by deforming and discharging gas at a predetermined pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional rectangular rechargeable battery structure is used with protruding terminals, then the battery can be charged and discharged, but it becomes very difficult to form a structure for interrupting current
Solution Approach 1:
The current interrupt unit is nested within the cap plate structure, with the convex member integrated into the cap plate's bottom surface. This nesting approach allows the interrupt mechanism to be embedded within the existing battery structure rather than adding external components, thereby enabling current interruption while maintaining structural simplicity.
Solution Approach 2:
The convex member acts as an intermediary element between the cap plate and the electrode assembly. It provides a mechanical interface that responds to internal pressure changes by deforming and breaking the welding part, thereby mediating the current interruption function without requiring complex additional structures.
2Reliability
If the battery is overcharged, then voltage and temperature increase, but the battery expands and life-span deteriorates abruptly
Solution Approach 1:
The current interrupt unit is designed to activate before severe overcharge damage occurs. The convex member is positioned and dimensioned such that when internal pressure reaches a predetermined level (indicating overcharge conditions), the convex member deforms and breaks the welding part, interrupting current flow and preventing further overcharge damage to the battery.
Solution Approach 2:
The invention converts the harmful effect of internal pressure buildup during overcharge into a beneficial safety mechanism. The pressure that would normally indicate dangerous overcharge conditions is instead utilized to activate the current interrupt unit, where the pressure-driven deformation of the convex member triggers current interruption, thereby protecting the battery from further damage.
3Reliability
If a current interrupt structure is added to prevent overcharge, then safety improves, but the device complexity increases
Solution Approach 1:
The current interrupt unit is merged with the cap plate structure, where the convex member is formed as an integral part of the cap plate's bottom surface. The insulating member is also integrated into the assembly, with the convex member passing through its hole. This merging of components reduces the number of separate parts and simplifies the overall structure while maintaining the current interruption safety function.
Solution Approach 2:
The current interrupt unit operates autonomously based on physical principles without requiring external control systems. The convex member automatically deforms under internal pressure and breaks the welding part connection when overcharge conditions occur, providing self-service safety protection without adding complex control circuitry or external monitoring systems.
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 solution effectively prevents overcharging by interrupting current flow and discharging gas, thereby reducing the risk of battery expansion, fire, or explosion, and enhancing safety by maintaining stable voltage and temperature.
Implementation Method 1
the convex member is configured to protrude toward the cap plate after separating from the sub-plate when an internal pressure of the rechargeable battery increases above a predetermined pressure
Data Source
AI summary
A rechargeable battery including: an electrode assembly with a positive electrode, a negative electrode and a separator interposed therebetween; a case housing the electrode assembly; a cap plate connected to the case; a first terminal and a second terminal protruding from an upper part of the cap plate; and a current interrupt module electrically connected to the electrode assembly and the first terminal, wherein the current interrupt module includes a current interrupt unit coupled to the electrode assembly and the current interrupt unit is configured to uncouple from the electrode assembly when an internal pressure of the case increases.