Zigzag-Folded Electrode Assembly for Uniform Separator Spacing
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Solution Overview
Problem
Existing electrode assemblies in secondary batteries face issues such as non-uniform inter-electrode intervals leading to electrical short circuits, decreased stability, and increased manufacturing time, which can result in battery ignition and overload.
Innovation Solution
An electrode assembly design featuring two layers of rectangular separators with a first electrode between them, thermally fused at the edges, folded zigzag, and sealed with a polyimide sealing member to prevent short circuits and external air contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a jelly-roll type electrode assembly is used, then the manufacturing process is simplified, but the inter-electrode intervals become non-uniform leading to electrical short circuits and decreased stability
Solution Approach 1:
The electrode assembly is divided into multiple unit assemblies, each with its own separators and electrodes. This segmentation allows each unit to maintain uniform inter-electrode intervals independently, preventing electrical short circuits while simplifying the overall manufacturing process through modular assembly.
Solution Approach 2:
Separators are introduced as intermediary elements between the positive and negative electrodes. These separators maintain consistent spacing and prevent direct contact between electrodes, ensuring uniform inter-electrode intervals and preventing electrical short circuits throughout the battery structure.
2Reliability
If a stack type electrode assembly is used, then the inter-electrode intervals remain uniform, but productivity decreases due to sequential stacking requirements
Solution Approach 1:
The electrode assembly is divided into multiple unit assemblies that can be manufactured independently and then combined. This segmentation enables parallel manufacturing of multiple units simultaneously, significantly improving productivity while maintaining the uniform inter-electrode intervals characteristic of stack-type assemblies.
Solution Approach 2:
Multiple unit assemblies are prepared in advance through preliminary manufacturing steps, allowing them to be manufactured independently and in parallel. This preliminary action enables subsequent rapid assembly of the complete battery, improving overall productivity while ensuring each unit maintains uniform spacing.
3Ease of manufacture
If conventional stack and folding-type electrode assembly is used, then manufacturing is possible, but a relatively large amount of time and effort is required in the manufacturing process
Solution Approach 1:
The electrode assembly is segmented into standardized unit assemblies with consistent structures. This segmentation allows for repetitive, standardized manufacturing processes that reduce the time and effort required for each unit, while the modular nature simplifies the overall assembly process.
Solution Approach 2:
The manufacturing process parameters are optimized by establishing standardized dimensions and configurations for unit assemblies. This standardization enables more efficient manufacturing processes, reducing the time and effort required while maintaining manufacturing feasibility.
4Ease of manufacture
If separators are not thermally fused, then manufacturing is simpler, but electrical short circuits occur due to thermal contraction at elevated temperatures
Solution Approach 1:
The separators undergo thermal fusion at elevated temperatures during manufacturing, transitioning from a non-fused state to a fused state. This phase transition creates a permanent bond that prevents thermal contraction at operating temperatures, ensuring reliable short circuit prevention while maintaining relatively simple manufacturing processes.
Solution Approach 2:
Thermal fusion of the separators is performed in advance during the manufacturing process, creating a pre-bonded structure that is resistant to thermal contraction. This preliminary action ensures that the separators maintain their spacing function throughout the battery's operational temperature range without requiring complex additional measures.
5Stress or pressure
If venting is allowed in battery cell, then pressure relief is achieved, but battery ignition is accelerated due to air inflow
Solution Approach 1:
The separators act as intermediary barriers that are thermally fused to create a sealed structure. This intermediary bonding prevents direct pathways for air to enter the battery cell during venting events, reducing the risk of battery ignition while still allowing pressure relief through controlled mechanisms.
Solution Approach 2:
The electrode assembly utilizes composite structures combining separators, electrodes, and thermal fusion bonds to create a sealed yet pressure-responsive system. This composite structure allows pressure relief while maintaining integrity against air infiltration that could lead to ignition.
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
This design enhances stability by preventing electrical short circuits and battery ignition, while allowing efficient manufacturing by simplifying the assembly process.
Implementation Method 1
at least a portion of an edge area of the two layers of separators is thermally fused in a state in which the first electrode is disposed between the two layers of separators
Implementation Method 2
the electrode-separator assembly in a state of being thermally fused is folded in a zigzag form... sealing a separator to block contact with outside air when venting in a battery cell occurs
Data Source
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AI summary
An electrode assembly is provided. An electrode assembly, according to one aspect of the present specification, comprises: an electrode-separator assembly including two layers of separators, each having a rectangular shape, and a first electrode disposed between the two layers of separators in a rectangular shape extending in a direction corresponding to the two layers of separators; and a second electrode separated from the first electrode by means of the separators, wherein at least a portion of the edge region of the two layers of separators is thermally fused in a state in which the first electrode is disposed between the two layers of separators, the electrode-separator assembly in the thermally fused state is folded in a zigzag pattern along the longitudinal direction, and the second electrode is disposed between layers of the folded and stacked electrode-separator assembly.