Lithium Battery Current Collector Structure for Internal Short Isolation
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Solution Overview
Problem
Lithium batteries are prone to short circuiting, leading to high temperature occurrences and potential fires due to manufacturing defects and degradation over time, which poses significant safety risks.
Innovation Solution
The use of thin metallized current collectors with high shrinkage rate materials and nonconductive materials that oxidize at high temperatures, creating an internal fuse mechanism within the battery to prevent heat buildup and fire during short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current collectors are used in lithium batteries, then electrical conductivity is maintained, but short circuits can occur leading to high temperature and fire hazards
Solution Approach 1:
The current collector is pre-designed with a fuse section that has lower melting point and higher resistance than the bulk material. This preliminary structural arrangement ensures that when a short circuit occurs, the fuse section will automatically melt and break the circuit before excessive heat can propagate through the battery, preventing thermal runaway without requiring external intervention.
Solution Approach 2:
The current collector is segmented into different functional zones: a bulk conductive section for normal current flow and a fuse section with specific sacrificial properties. This segmentation allows the current collector to serve dual purposes - maintaining electrical conductivity during normal operation while providing a controlled failure point for safety during abnormal conditions.
2Reliability
If an internal fuse mechanism is implemented to prevent short circuits, then safety is improved, but the device complexity increases
Solution Approach 1:
The fuse function is merged directly into the current collector structure itself, eliminating the need for separate fuse components. The fuse section is integrated as an inherent part of the current collector, using the same material deposition processes but with locally adjusted properties (lower melting point, higher resistance). This integration maintains structural simplicity while providing safety functionality.
Solution Approach 2:
The current collector serves multiple functions: it provides electrical conductivity for normal operation, acts as a structural support element, and simultaneously functions as a safety device through its integrated fuse section. This multi-functionality reduces the need for additional safety components, maintaining device simplicity while improving safety.
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 solution effectively breaks the conductive pathway during an internal short, immediately stopping current flow and preventing heat generation, thereby containing the short circuit and preventing thermal runaway and fires.
Implementation Method 1
materials that become nonconductive upon exposure to high temperatures
Implementation Method 2
such a conductive pathway may then cause a discharge of the cell therethrough which ultimately generates excessive heat
Data Source
AI summary
Improvements in the structural components and physical characteristics of lithium battery articles are provided. Standard lithium ion batteries, for example, are prone to certain phenomena related to short circuiting and have experienced high temperature occurrences and ultimate firing as a result. Structural concerns with battery components have been found to contribute to such problems. Improvements provided herein include the utilization of thin metallized current collectors (aluminum and/or copper, as examples), high shrinkage rate materials, materials that become nonconductive upon exposure to high temperatures, and combinations thereof. Such improvements accord the ability to withstand certain imperfections (dendrites, unexpected electrical surges, etc.) within the target lithium battery through provision of ostensibly an internal fuse within the subject lithium batteries themselves that prevents undesirable high temperature results from short circuits. Battery articles and methods of use thereof including such improvements are also encompassed within this disclosure.