Multi-Functional Cathode Current Collector for Thermal Runaway Blocking
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Solution Overview
Problem
Nickel-rich cathode active materials in battery cells are thermally unstable, leading to the decomposition of materials and the release of molecular oxygen, which increases the risk of thermal runaway events.
Innovation Solution
A multi-functional cathode current collector is introduced, comprising a cathode current collector made of aluminum or stainless steel, a positive temperature coefficient (PTC) material layer, and a conductive layer. The PTC material layer, doped with specific materials, increases resistance at elevated temperatures, preventing thermal runaway while maintaining electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-rich cathode active material is used to increase capacity, then battery capacity is improved, but thermal stability deteriorates leading to thermal runaway risk
Solution Approach 1:
A PTC layer is introduced as an intermediary between the nickel-rich cathode active material and the current collector. This layer contains PTC material (such as barium titanate or lead zirconate titanate) that exhibits positive temperature coefficient behavior, dramatically increasing its resistance at elevated temperatures to block electron flow and prevent thermal runaway while maintaining good electrochemical performance at normal operating temperatures.
Solution Approach 2:
The current collector structure is designed as a composite system consisting of the metallic current collector substrate and a PTC material layer coated on its surface. This composite structure combines the high conductivity and mechanical strength of the metal current collector with the thermal protection properties of the PTC material, achieving both high capacity and thermal stability.
2Reliability
If PTC material layer is added to prevent thermal runaway, then thermal stability is improved, but device complexity increases
Solution Approach 1:
The PTC layer serves multiple functions simultaneously: it provides thermal protection through positive temperature coefficient behavior, acts as a conductive layer for electron transport at normal temperatures, and can function as a binder layer to hold the cathode active material particles together. This multi-functionality reduces the need for separate protective layers and simplifies the overall structure.
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 multi-functional cathode current collector significantly enhances thermal stability by increasing resistance by a factor of 5×10^5 at 100°C, effectively blocking electron flow and preventing thermal runaway events without compromising electrochemical performance at lower temperatures.
Implementation Method 1
a positive temperature coefficient (PTC) material layer, and a conductive layer. The PTC material layer, doped with specific materials, increases resistance at elevated temperatures, preventing thermal runaway while maintaining electrochemical performance
Implementation Method 2
increasing resistance by a factor of 5×10^5 at 100°C, effectively blocking electron flow and preventing thermal runaway events
Data Source
AI summary
A cathode electrode includes a multi-functional cathode current collector including a cathode current collector and a layer including a positive temperature coefficient (PTC) material arranged adjacent to the cathode current collector. A cathode active material layer is arranged on the multi-functional cathode current collector and includes a cathode active material including nickel.