Bipolar Electrode Assembly With Thermal-Fused Electrolyte Sealing
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Solution Overview
Problem
Existing bipolar electrodes in lithium secondary batteries face issues with electrolyte migration and potential short circuits due to contact between current collectors, requiring additional structures like conductive sealing films and polymer layers to prevent electrolyte migration, which complicates the design.
Innovation Solution
A bipolar electrode with a polymer film having a conductive layer on its surface and a thermally fusible outer periphery is used as a current collector, allowing for simplified structure and preventing electrolyte migration by thermal fusion of the outer peripheries, forming independent unit electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate conductive sealing film and polymer layer are added to prevent electrolyte migration, then electrolyte separation is improved, but device complexity increases
Solution Approach 1:
The patent combines the sealing function and conductive function into a single integrated current collector structure. The current collector itself is designed with an outer peripheral region that provides sealing while the inner active region provides electrical conductivity, eliminating the need for separate sealing films and polymer layers.
Solution Approach 2:
The current collector is designed to perform multiple functions simultaneously: it serves as both the electrical conductor and the sealing barrier. The differential porosity structure enables the same component to provide both conductive pathways in the active region and electrolyte sealing at the periphery, reducing the total number of components required.
2Reliability
If adhesive and separate members are added to fix current collectors, then contact prevention is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces the mechanical adhesive bonding system with a thermal fusion system. The outer peripheral region of the current collector is designed to be thermally fusible, allowing adjacent current collectors to be joined together through heat treatment, eliminating the need for adhesives and separate fixing members.
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 effectively prevents electrolyte migration between bipolar electrodes while maintaining electrical connectivity, simplifying the structure and reducing the need for additional components, thus enhancing the reliability and efficiency of the battery.
Implementation Method 1
a thermally fusible outer periphery is used as a current collector, allowing for simplified structure and preventing electrolyte migration by thermal fusion of the outer peripheries
Data Source
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Figure 3(a)~3(b)
AI summary
Disclosed is a bipolar electrode including a current collector including a polymer film and conductive layer added to at least a part of each of an outer surface and an inner surface of the polymer film, a positive electrode formed on a first surface of the current collector, and a negative electrode formed on a second surface of the current collector, wherein the current collector including the polymer film is thermally fused so as to be sealed, whereby migration of an electrolyte between unit electrodes is prevented.