Electrode Assembly Dual Sealing Separator Thermal Contraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary battery electrode assemblies manufactured using the lamination and stacking method face limitations in thermal stability due to separator contraction, leading to potential short circuits and safety risks, and existing single-sealing methods are inadequate in preventing these issues.
Innovation Solution
The electrode assembly features a doubly sealed separator structure, with a first inner sealing part within each radical unit and an outer sealing part formed by sealing the separators outside the inner sealing part, preventing contact between positive and negative electrodes during thermal contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator size is increased to account for thermal contraction, then thermal stability is improved, but manufacturing cost increases
Solution Approach 1:
The sealing structure is divided into two distinct segments: an inner sealing part that seals the separator to the electrode within the radical unit, and an outer sealing part that seals the separator at the unit stack level. This segmentation allows each sealing part to address specific aspects of thermal contraction, enabling the use of a separator with size closer to the actual electrode dimensions rather than requiring excessive oversizing.
Solution Approach 2:
The dual sealing structure acts as a preventive measure against thermal contraction before it can cause short circuits. The inner sealing part provides the first line of defense by securing the separator to the electrode, while the outer sealing part provides a second line of defense at the unit stack level, cushioning against the harmful effects of thermal contraction without requiring excessive separator material.
2Device complexity
If single sealing method is used to reduce manufacturing complexity, then device complexity is reduced, but reliability against short circuit deteriorates
Solution Approach 1:
The sealing function is segmented into two distinct sealing parts performed at different levels: inner sealing at the radical unit level and outer sealing at the unit stack level. This segmentation allows each sealing operation to be optimized for its specific purpose while maintaining overall system reliability, without requiring a single overly complex sealing mechanism.
Solution Approach 2:
The sealing structure follows a nested arrangement where the inner sealing part is contained within the radical unit, and the outer sealing part encompasses multiple radical units at the unit stack level. This nested structure provides multiple layers of protection against short circuits while maintaining a relatively simple and systematic manufacturing process.
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 dual sealing structure effectively prevents short circuits and enhances battery safety without increasing manufacturing costs or complexity, improving thermal stability and reliability.
Implementation Method 1
In a heating process, the electrodes and the separator, which are combined to improve bonding force between the separator and the electrodes
Implementation Method 2
the electrodes and the separator are bonded to each other by heat and a pressure
Implementation Method 3
the electrodes and the separator are bonded to each other by heat and a pressure
Implementation Method 4
contact between a positive electrode and a negative electrode due to contraction of the separator
Data Source
AI summary
An electrode assembly includes a separator, which is doubly sealed in a radical unit and a unit stack part to prevent short circuit occurring by contact between a positive electrode and a negative electrode due to contraction of the separator. The electrode assembly includes a unit stack part having a stacked structure including a plurality of radical units and an outer sealing part formed outside the unit stack part. Each of the radical unit is formed by alternately stacking electrodes and separators and includes a first inner sealing part in which a plurality of separators vertically stacked on the electrodes are sealed to each other on a side surface of each of the electrodes, and the outer sealing part is formed by sealing the separators of the plurality of radical units to each other outside the first inner sealing part.