Pouch Battery Swelling Tape Electrode Stability
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Solution Overview
Problem
Pouch-type secondary batteries face safety issues due to internal shorts caused by electrode plate movement during vibration or collision, which can lead to contact with tabs and result in fires.
Innovation Solution
The battery design includes taping the end part of the electrode assembly where tabs converge, along the stack thickness-wise direction, to prevent electrode plates from poking out and contacting tabs, using a swelling tape that expands with electrolyte solution to fill empty spaces and enhance safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pouch-type secondary battery is designed with empty space between pouch case and electrode assembly, then flexibility and ease of manufacturing are improved, but safety deteriorates due to risk of internal short from electrode movement during vibration or collision
Solution Approach 1:
A buffer member is introduced as an intermediary component between the electrode assembly and the pouch case. This buffer member fills the empty space and prevents direct contact between the electrode assembly and the pouch case wall, thereby eliminating the harmful effect of electrode movement during vibration or collision while maintaining the flexible pouch structure.
Solution Approach 2:
The buffer member is pre-installed within the pouch case to provide cushioning protection before any vibration or collision occurs. This beforehand cushioning ensures that when external shocks or vibrations occur, the electrode assembly is already protected from moving and contacting the pouch case wall, preventing internal shorts before they can happen.
2Reliability
If electrode assembly is secured tightly to prevent movement, then safety is improved, but manufacturing complexity and device complexity increase
Solution Approach 1:
The buffer member serves as a simple intermediary component that passively prevents electrode movement without requiring complex securing mechanisms. Unlike active fixing methods that would add complexity, the buffer member simply occupies the empty space and provides mechanical protection through its physical presence.
Solution Approach 2:
The buffer member is designed as a flexible component that can deform and adapt to the pouch case interior shape. This flexibility allows it to provide effective protection against electrode movement while maintaining the overall flexible nature of the pouch battery structure, avoiding the need for rigid or complex securing structures.
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 taping solution effectively prevents internal shorts and enhances the safety of pouch-type secondary batteries by securing the electrode assembly and filling empty spaces, thereby reducing the risk of contact and fire.
Implementation Method 1
an end part of the electrode assembly at a part where the tabs converge is taped wrapping an outer peripheral surface of the electrode assembly tightly, along a stack thickness-wise direction of the electrode assembly
Data Source
AI summary
The present invention provides a pouch-type secondary battery comprising: an electrode assembly having, repeatedly stacked therein, unit cells comprising a positive plate, a negative plate, and a separator positioned between the positive and negative plates, wherein the positive plate and negative plate are respectively provided with a positive electrode tab and a negative electrode tab, and the positive and negative electrode tabs each converge in a predetermined direction; and a pouch case for sealing the electrode assembly, the pouch-type secondary battery being characterized by taping in contact with the outer circumferential surface of the electrode assembly along the stacking thickness direction of the electrode assembly, at the end of the electrode assembly at the part where the tabs converge, thereby improving the safety of the pouch-type secondary battery.