Copper Foil Pouch Cell with Polyisobutylene Insulation
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Solution Overview
Problem
Existing battery cell construction methods face challenges in creating efficient and reliable pouch cells with stable electrical isolation and effective sealing to prevent shorting, while ensuring compatibility with various battery chemistries and materials.
Innovation Solution
The development of a pouch cell design using a copper foil pouch with an active material layer forming a cathode, a lithium-based anode, and a separator, along with a polyisobutylene insulating coating to prevent electrical shorting and a method for constructing the cell that includes preparing a copper foil pouch, applying the active material, inserting the lithium-based anode and electrolyte, and sealing the pouch with a second terminal tab.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a copper foil pouch is used to form the battery cell, then electrical conductivity and efficiency are improved, but electrical shorting between internal components may occur
Solution Approach 1:
An insulating layer comprising polyisobutylene is applied to the exterior surface of the copper foil pouch. This intermediary layer prevents electrical shorting between the copper foil and external components while maintaining the high electrical conductivity of the copper foil for efficient power transmission within the battery cell.
Solution Approach 2:
A thin film insulating coating of polyisobutylene is applied to the copper foil pouch. This flexible thin film provides effective electrical isolation without adding significant bulk, maintaining the compact structure while preventing harmful electrical contact between internal components and external elements.
2Reliability
If the pouch cell structure is sealed to prevent shorting, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The sealing function and insulating function are merged into a single integrated step by applying the polyisobutylene insulating coating that also serves as a sealing layer. This combination eliminates the need for separate sealing operations, reducing manufacturing complexity while ensuring both electrical isolation and reliable sealing to prevent shorting.
Solution Approach 2:
The polyisobutylene layer serves multiple functions simultaneously: it provides electrical insulation to prevent shorting, acts as a sealing barrier to protect internal components, and maintains structural integrity. This multi-functionality simplifies the overall device structure and manufacturing process while ensuring reliability.
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 provides a stable and efficient battery cell with adequate electrical isolation, capable of powering loads such as LEDs, and allows for the production of cells with varying sizes and capacities, demonstrating effective electrical isolation and resistance to internal components.
Implementation Method 1
An insulating layer may be applied to an exterior surface of the copper foil pouch. The insulating layer may comprise polyisobutylene.
Implementation Method 2
a separator interposing the one active material layer and the lithium-based anode
Implementation Method 3
an active material layer adjacent to the copper foil inside the pouch forming a cathode with the copper, and a lithium-based anode inside the pouch
Data Source
AI summary
A pouch cell includes a copper foil forming a pouch, an active material layer adjacent to the copper foil inside the pouch forming a cathode with the copper, and a lithium-based anode inside the pouch. The cell includes a separator interposing the one active material layer and the lithium-based anode, and an electrolyte. In other embodiments, the active material forms an anode with the copper and the cathode is a lithium-based cathode.