Multi-layered Electrochemical Cell Thermal Welding Safety
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Solution Overview
Problem
Existing electrochemical cells, such as jelly-roll and stacking types, face issues with electrode detachment and short circuits due to external impacts and vibrations, leading to potential fires or explosions, especially in prismatic and pouch-shaped batteries.
Innovation Solution
A multi-layered electrochemical cell structure where full cells or bicells are folded using a long separation film, with separators secured by thermal welding to prevent electrode separation and twisting, maintaining structural stability and preventing heat generation or fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a long continuous separation film is used to fold full cells or bicells, then the battery can achieve a compact prismatic or pouch-shaped structure with high integration, but the electrodes may be separated from the separation film or twisted due to impacts and vibrations, causing short circuits
Solution Approach 1:
The patent applies preliminary action by pre-securing the separators to the long continuous separation film using thermal welding before the battery is subjected to impacts or vibrations. This advance fixation ensures that the electrodes remain properly positioned and connected even when external forces are applied during battery operation or transport.
Solution Approach 2:
The patent replaces the purely mechanical attachment (physical folding and positioning) with thermal welding, which uses heat to create a permanent bond between the separators and the separation film. This substitution of mechanical connection with thermal bonding provides superior resistance to impacts and vibrations that would otherwise cause electrode detachment or twisting.
2Ease of manufacture
If separators are not secured to the separation film, then the manufacturing process is simpler, but external impacts and vibrations cause electrode separation and twisting leading to short circuits
Solution Approach 1:
The patent replaces the purely mechanical attachment (physical folding and positioning) with thermal welding, which uses heat to create a permanent bond between the separators and the separation film. This substitution of mechanical connection with thermal bonding provides superior resistance to impacts and vibrations that would otherwise cause electrode detachment or twisting.
Solution Approach 2:
The patent changes the physical state and bonding parameters by applying heat through thermal welding, transforming the separation film and separator materials from a loosely positioned state to a permanently bonded state. This parameter change (from mechanical positioning to thermal bonding) fundamentally improves the resistance to external impacts and vibrations.
3Reliability
If thermal welding is used to secure separators to the separation film, then electrode separation and twisting are prevented under external impacts, but the manufacturing process becomes more complex
Solution Approach 1:
The long continuous separation film serves multiple functions: it acts as the separator between electrodes, provides the folding structure for compact battery geometry, and serves as the substrate to which separators are thermally welded for securing electrodes. This multi-functionality consolidates several components into one, reducing overall manufacturing complexity despite the addition of thermal welding.
Solution Approach 2:
The patent merges the separation film and separators into a unified structure through thermal welding, creating an integrated assembly where the separators are permanently bonded to the separation film. This merging eliminates the need for separate securing mechanisms and reduces the number of discrete components, thereby simplifying the overall manufacturing process despite the introduction of thermal welding technology.
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 reduces short circuit occurrences and maintains structural integrity under external impacts and temperature changes, enhancing safety and stability of the electrochemical cell.
Implementation Method 1
separators of the unit cells are secured to the separation film by thermal welding
Data Source
AI summary
Disclosed herein is an electrochemical cell constructed in a structure in which a plurality of full cells or bicells, as unit cells, are folded by a separation film formed in the shape of a long sheet, and separators of the unit cells are secured to the separation film by thermal welding. The electrochemical cell according to the present invention has the effect of preventing the electrodes of the stacked electrodes from being separated from the separation film or from being twisted due to external impacts and vibrations, thereby restraining the electrochemical cell from generating heat or catching fire. Furthermore, the structural stability of the electrochemical cell is maintained even when the temperature of the electrochemical cell is increased, or the volume of the electrochemical cell is increased due to the generation of gas.