Pouch Battery Notched Electrode Lead for Pressure Safety
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Solution Overview
Problem
Conventional pouch-shaped secondary batteries face safety risks due to pressure increases from gas generation during abnormal states or overcharging, leading to potential explosions, and existing protection circuits are insufficient in preventing electrical current flow during such conditions.
Innovation Solution
A pouch-shaped secondary battery design featuring an electrode lead with a notch formed in a lead box on the battery case, which allows for controlled interruption of electric current flow when pressure increases, using a closed-loop-type or pair of notches to securely disconnect the electrode lead and prevent energy density reduction without additional complex devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection circuit is added to prevent overcharging, then battery safety is improved, but device complexity increases
Solution Approach 1:
The electrode lead is designed with a self-service safety mechanism where the lead itself performs the protection function through its structural features (notches and deformation characteristics). When abnormal pressure occurs, the electrode lead automatically deforms or breaks at the notch to interrupt current flow, eliminating the need for external protection circuits to perform this specific safety function.
2Reliability
If additional safety devices are added to interrupt current flow, then battery safety is improved, but energy density is reduced
Solution Approach 1:
The safety function is merged into the existing electrode lead structure rather than being implemented as a separate device. The electrode lead combines both its primary function (current conduction) and safety function (current interruption upon abnormal pressure) within a single component, avoiding the energy density loss that would result from adding separate safety devices.
Solution Approach 2:
The safety function is extracted from the electrode lead material itself through structural modification (adding notches) rather than requiring additional materials or components. This allows the safety mechanism to be implemented with minimal impact on the overall energy density of the battery system.
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 notch configuration in the electrode lead effectively interrupts electric current flow during abnormal states, enhancing battery safety by preventing explosions and maintaining energy density without the need for additional devices, thus improving overall safety and performance.
Implementation Method 1
an electrode lead having a notch formed in a lead box on a battery case in order to interrupt an electric current flow when a pressure inside the battery cell increases
Data Source
AI summary
Disclosed herein is a pouch-shaped secondary battery including an electrode assembly in which a positive electrode and a negative electrode are stacked with a separator interposed, an electrode lead electrically connected to electrode tabs of the electrode assembly, a pouch-shaped battery case made of a laminate sheet including an outer coating layer, a metal layer, and an inner sealant layer, and a lead box disposed on a sealed portion of the battery case for receiving the electrode lead. In particular, the electrode lead includes a lower electrode lead, which is electrically connected to the electrode tabs, and an upper electrode lead, a portion of which is coupled to the lower electrode lead.