Protective Layer with Small Molecule Additives for Battery Safety
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Solution Overview
Problem
Battery cells are prone to overcharging, overheating, and short-circuiting, which can lead to thermal runaway, a hazardous condition that may result in fires or explosions, and existing solutions do not adequately address these safety concerns.
Innovation Solution
A protective layer is introduced in battery cells, composed of small molecule additives combined with functional and conductive materials, which can interrupt current flow upon temperature, voltage, or current increases, and is further enhanced by a sealing layer to prevent unwanted reactions with other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is added to mitigate thermal runaway hazards, then safety is improved, but device complexity increases
Solution Approach 1:
The protective layer combines multiple materials (conductive material, functional material, and small molecule additives) into a single integrated layer that performs both safety protection and current collection functions, eliminating the need for separate protective and current-collecting components
Solution Approach 2:
The protective layer serves multiple functions simultaneously: it provides thermal runaway protection, collects current, and maintains battery performance, thereby reducing the need for additional dedicated components and simplifying the overall device structure
2Reliability
If small molecule additives are used to improve protective layer stability and conductivity, then performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the concentration range of small molecule additives (0.1-10 wt%, preferably 0.5-5 wt%) to achieve the desired balance between stability and conductivity while maintaining manufacturing feasibility. This parameter optimization reduces the precision requirements compared to using pure functional materials
Solution Approach 2:
The protective layer uses a composite formulation combining conductive materials, functional materials, and small molecule additives in specific ratios. This composite approach provides manufacturing flexibility and tolerances that reduce precision requirements while achieving target performance levels
3Reliability
If the protective layer is designed to interrupt current flow upon temperature increase, then safety is improved, but energy loss increases
Solution Approach 1:
The protective layer's electrical conductivity dynamically adjusts based on temperature: it maintains high conductivity for current collection during normal operation, and transitions to low conductivity to interrupt current flow when thermal runaway conditions are detected, thereby minimizing energy loss during normal operation while providing safety protection when needed
Solution Approach 2:
The protective layer utilizes temperature-induced phase transitions or conductivity changes to switch between current collection mode and current interruption mode. This phase transition mechanism allows the layer to maintain energy efficiency during normal operation while automatically activating safety protection when temperature thresholds are exceeded
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 protective layer effectively mitigates hazardous conditions by arresting exothermic reactions and maintaining stability, improving the battery cell's safety and performance by reducing the risk of thermal runaway and enhancing capacity retention and high-temperature stability.
Implementation Method 1
The protective layer may be configured to respond to an increase in temperature, voltage, and/or current by interrupting a flow of current within the battery cell
Implementation Method 2
a first protective layer reducing or interrupting a current flow within the battery cell upon activation
Implementation Method 3
The protective layer may include one or more small molecule additives to facilitate cross linking and improve the stability and conductivity of the protective layer
Data Source
AI summary
A battery cell may include an electrolyte, a first electrode including a first electrode layer and a first current collector, a second electrode including a second electrode layer and a second current collector, a separator interposed between the first electrode and the second electrode, and at least one protective layer. For example, a protective layer may be interposed between the first electrode layer and the first current collector, the second electrode layer and the second current collector, the separator and the first electrode, and/or the separator and the second electrode. When activated, the one or more protective layers may reduce or interrupt current flow through the battery cell. The composition of the one or more protective layers may include one or more small molecule additives to increase its stability and conductivity, thus improving the performance as well as the safety profile of the battery cell.