Dual Electrode Lead Design for Pouch Battery Safety
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to overcharging, leading to electrolyte decomposition, gas generation, and potential ignition or explosion, with existing solutions either affecting battery quality or increasing manufacturing costs.
Innovation Solution
A pouch-type secondary battery design featuring dual electrode leads connected by a film-like connection member, which interrupts electric current when internal pressure exceeds a critical value, preventing further charging and allowing venting to improve safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current interruptive device (CID) is provided to interrupt electric current and release internal pressure upon abnormal operation, then battery safety is improved, but manufacturing cost increases and manufacturing process becomes complicated
Solution Approach 1:
The patent extracts the safety function from a separate CID device and integrates it directly into the electrode lead structure. The electrode lead itself becomes the current interruptive element through its connection to the pouch portion, eliminating the need for an additional CID component and simplifying the manufacturing process while maintaining safety functionality.
Solution Approach 2:
The patent merges the current-conducting function and the current-interrupting safety function into a single integrated structure. The electrode lead is combined with the pouch portion connection such that the same structural element performs both electrical conduction and pressure-based current interruption, reducing device complexity.
2Reliability
If an additive is added to electrolyte to prevent overcharge, then battery safety is improved, but battery quality deteriorates
Solution Approach 1:
The patent replaces the chemical approach (electrolyte additives) with a mechanical approach. Instead of using chemical additives to prevent overcharge, the invention uses the mechanical swelling of the pouch portion under pressure to physically interrupt the electrode lead connection, thereby cutting off current flow through a mechanical rather than chemical mechanism.
3Reliability
If dual electrode leads are connected by a film-like connection member, then current interruption capability is improved, but device structure becomes more complex
Solution Approach 1:
The patent employs a film-like connection member to connect the first and second electrode leads. This thin film structure provides the necessary electrical connection while allowing the connection to be interrupted when the pouch portion swells under pressure, achieving current interruption capability through the flexible film's ability to deform and disconnect.
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 dual electrode lead design effectively prevents overcharging by interrupting electric current and enhances the stability of the battery cell, module, and pack by allowing controlled venting, thereby improving safety and extending battery life.
Implementation Method 1
interrupt electric current by volumetric swelling caused by swelling or pressure upon overcharge of a secondary battery
Data Source
AI summary
A pouch type secondary battery includes an electrode assembly and a pouch sheath material including a first pouch portion and a second pouch portion. The pouch-type secondary battery includes dual electrode leads wherein a first electrode lead is attached to the first pouch portion and a second electrode lead is attached to the second pouch portion. In the pouch-type secondary battery, electric current is interrupted by using a volumetric swelling phenomenon caused by swelling or pressure generated upon overcharge so that the battery may be prevented from being further charged. In addition, when pressure is increased by an additional reaction, venting occurs toward the inner lead portion of each of the dual electrode leads. As a result, it is possible to increase the stability of a battery cell, module and a pack received in the pouch, and thus to improve the life of a battery.