Multi-Layer Battery Separator with Overlapping Shutdown Temperature Ranges
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Solution Overview
Problem
Current battery separators have limited temperature shutdown ranges, which can lead to premature battery shutdown due to pore collapse or breakdown, resulting in safety issues and reduced operational efficiency.
Innovation Solution
The use of multiple layers with distinct shutdown temperature ranges, where the first and second layers overlap, and the second and third layers overlap, but not the first and third, to create a sandwiched structure that enhances the temperature range for safe battery operation, allowing for a broader range of safe ion transport before shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single-layer separator is used, then the structure is simple and manufacturing is easier, but the temperature shutdown range is limited
Solution Approach 1:
The separator is divided into multiple layers, each with distinct shutdown temperature ranges. The first layer has a shutdown temperature range of 80-250°C, the second layer has a shutdown temperature range of 150-300°C, and the third layer has a shutdown temperature range of 250-450°C. This segmentation allows each layer to independently respond to different temperature conditions, thereby extending the overall shutdown temperature range while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The separator employs composite material construction with three distinct layers made from different materials optimized for specific temperature ranges. This composite structure combines the advantages of each material to achieve a broader operational temperature window, where the first layer (lower temperature range) provides initial safety shutdown, the second layer (intermediate range) provides extended protection, and the third layer (higher temperature range) provides high-temperature safety assurance.
2Temperature
If the lower temperature limit is decreased to extend shutdown range, then battery safety improves, but ion transport efficiency decreases due to premature pore collapse
Solution Approach 1:
The temperature protection function is segmented across three layers with progressively higher shutdown temperature ranges. The first layer handles lower temperature shutdown (80-250°C), the second layer handles intermediate temperatures (150-300°C), and the third layer handles high temperatures (250-450°C). This segmentation ensures that ion transport is maintained at optimal efficiency across the full operating range, with each layer activating only when its specific temperature threshold is reached, rather than having a single layer restrict ion transport across all temperatures.
Solution Approach 2:
The shutdown temperature parameters are optimized for each layer to create overlapping but distinct operational windows. The first layer's upper limit (250°C) overlaps with the third layer's lower limit (250°C), while the second layer provides coverage in between (150-300°C). This parameter optimization ensures continuous protection without premature shutdown, maintaining ion transport efficiency while extending the overall safety temperature range.
3Temperature
If the upper temperature limit is increased to extend shutdown range, then battery safety improves, but the separator becomes more susceptible to breakdown and melting
Solution Approach 1:
The high-temperature protection function is segmented across the second and third layers. The second layer provides intermediate temperature protection (150-300°C) with good stability, while the third layer provides high-temperature protection (250-450°C) using materials specifically selected for their thermal stability. This segmentation allows the upper temperature limit to be extended to 450°C without compromising overall separator reliability, as each layer is designed to maintain structural integrity within its specific temperature window.
Solution Approach 2:
The composite structure uses materials with progressively higher thermal stability from the first to the third layer. The third layer incorporates high-temperature resistant materials that maintain separator stability and prevent breakdown even at 450°C, while the first and second layers provide stable performance at lower temperatures. This composite material selection ensures that the extended upper temperature limit does not compromise separator reliability across the full operating range.
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 configuration extends the shutdown temperature range, improving battery safety by delaying pore collapse and preventing uncontrolled thermal runaway, while maintaining effective ion transport within safe limits.
Implementation Method 1
The lower temperature limit corresponds to an onset of pore collapse, which rapidly chokes off ion transport through the separator
Implementation Method 2
Materials for separators are often selected according to softening temperatures, above which, pores rapidly collapse
Data Source
AI summary
Battery separators are presented having improved temperature ranges for battery shutdown. The battery separators include a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature. The second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. In some embodiments, the second layer is disposed between the first layer and the third layer to create a sandwiched structure.