Battery Cell Potting Foam for Lightweight Flame Retardancy
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Solution Overview
Problem
Existing battery modules lack a potting compound that provides mechanical stability and flame retardancy while maintaining a lightweight design, and there is a need for a composition that can form a foam with sufficient flowability to settle around electric cells before curing.
Innovation Solution
A potting compound formed from a mixture of an isocyanate reactive compound and an isocyanate compound, including a blowing agent and a liquid flame retardant, which cures to form a low-density foam with at least V2 level flame resistance, providing mechanical stability and flame retardancy to battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potting compound provides mechanical stability and flame retardancy, then the battery module safety and structural integrity are improved, but the weight of the battery module increases
Solution Approach 1:
The patent employs a composite foam structure combining organic polymer matrix with inorganic flame retardant particles (such as aluminum hydroxide, magnesium hydroxide, or boron nitride). This composite approach provides flame retardancy through the inorganic components while the foam structure maintains low density, thus achieving fire protection without excessive weight gain.
Solution Approach 2:
The patent utilizes a foam-based potting compound with controlled porosity and cellular structure. The foam architecture provides mechanical stability through its three-dimensional cell structure while the void spaces reduce material density and weight. The porous structure also allows for flame retardant additives to be distributed throughout the matrix, enhancing fire resistance without proportionally increasing weight.
2Strength
If a potting compound provides mechanical stability, then the shock and vibration resistance of the battery module is improved, but the density and weight of the compound increase
Solution Approach 1:
The foam structure with its three-dimensional cellular network provides mechanical strength and shock absorption through the cell walls and nodes that distribute and dissipate impact forces. The porous architecture reduces material density while maintaining structural integrity, allowing the compound to withstand shock and vibration without excessive weight.
Solution Approach 2:
The combination of polymer matrix with reinforcing fillers or flame retardant particles creates a composite foam where the inorganic components enhance mechanical properties such as compressive strength and rigidity. This composite approach allows achieving required mechanical stability with lower overall density compared to solid non-foam materials.
3Reliability
If a flame retardant is added to the potting compound, then the flame resistance is improved, but the viscosity of the compound increases
Solution Approach 1:
The patent controls the particle size, shape, and surface characteristics of flame retardant additives to optimize their dispersion and minimize their impact on viscosity. By adjusting processing parameters such as mixing temperature, shear rate, and additive concentration within optimal ranges, the compound maintains workable viscosity while achieving required flame resistance levels.
Solution Approach 2:
The use of coupling agents, surfactants, or surface-modified flame retardant particles acts as intermediaries between the additive and polymer matrix. These intermediaries improve compatibility and dispersion of flame retardants, reducing agglomeration and the resulting viscosity increase, thereby maintaining ease of processing while achieving fire protection.
4Weight of stationary object
If a low-density foam structure is used, then the weight is reduced, but the mechanical strength and stability decrease
Solution Approach 1:
The foam is formulated as a composite material where inorganic fillers, fibers, or flame retardant particles are embedded in the polymer matrix. These reinforcing components compensate for the reduced material density by providing structural support through their higher strength-to-weight ratio, maintaining mechanical stability while keeping the overall density low.
Solution Approach 2:
The foam's cellular structure is designed with optimized cell size, wall thickness, and density distribution to balance weight reduction and mechanical strength. The three-dimensional network of cell walls provides structural support and shock absorption, while the void spaces reduce material usage and weight. Reinforcing agents within the foam further enhance mechanical properties without significantly increasing density.
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 achieves a lightweight battery module with enhanced mechanical stability and flame retardancy, ensuring protection against shock, vibration, and potential fire hazards, while maintaining structural integrity and thermal isolation of individual cells.
Implementation Method 1
The potting compound is formed from the reaction product of a first component having an isocyanate reactive compound; and a second component having an isocyanate compound
Implementation Method 2
The potting compound may further include a blowing agent
Data Source
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AI summary
The invention is directed to using a liquid potting composition for forming a polyurethane foam potting compound that encapsulates electric cells in a battery case at substantially the same height, wherein the potting composition is poured around the electric cells and has sufficient flowability such that it disperses and settles at a level height around the electric cells before the potting composition hardens to form the potting compound.