The Application of Expandable Graphite in Fire Protection for New Energy Vehicle Battery Packs

New energy vehicles are placing increasingly higher demands on the safety of power batteries. After a cell experiences thermal runaway, how to slow the spread of high temperatures and flames to adjacent cells and modules is a critical issue in battery pack fire protection design. Expandable graphite rapidly expands when heated, forming an insulating layer; as a result, it is used in some battery pack fire protection materials to provide a passive barrier against thermal runaway.

Expandable graphite is a material derived from natural flake graphite through an intercalation process. When the temperature reaches its expansion threshold, the interlayer material undergoes a transformation, causing the graphite flakes to expand rapidly in the vertical direction and form a loose, expanded carbon layer. This expanded structure increases resistance to heat transfer and creates a certain degree of physical isolation on the material’s surface. Therefore, incorporating expandable graphite into battery thermal runaway protection materials allows its thermal expansion properties to form a thermal barrier during high-temperature events, helping to delay the propagation of heat to adjacent areas.

Currently, expandable graphite can be composite with various matrix materials for use in fire-resistant and thermal insulation materials related to battery packs. One common application is in expandable fire-resistant separators or gaskets, where materials containing expandable graphite are positioned between battery cells, modules, or other locations requiring thermal isolation. When local temperatures rise, the material expands, thereby forming a thermal insulation layer. Another application involves fire-resistant coatings and composite thermal insulation materials. Expandable graphite can be blended with resins, silicones, aerogels, or other high-temperature-resistant materials, enabling the material to provide both expansion-based thermal barrier and structural protection functions simultaneously. For different battery pack structures, the material’s expansion ratio, particle size, expansion onset temperature, and compatibility with the matrix must be selected based on the specific formulation.

For battery pack fire protection applications, one cannot focus solely on the expansion ratio of expandable graphite. During actual development, it is also necessary to comprehensively consider particle size, expansion onset temperature, expansion volume, fixed carbon content, and compatibility with resins or other matrices. Different applications may also have varying requirements for graphite specifications. For example, fine-particle products are more suitable for certain coating and composite material systems, while products with different expansion ratios must be matched based on the target fire protection performance and material structure. Therefore, for battery material manufacturers, selecting a reliable supplier of expandable graphite and conducting sample testing based on actual formulations are critical steps in determining product specifications.

We have long been engaged in the production and processing of graphite materials and offer expandable graphite products with varying particle sizes and expansion properties, suitable for fire-resistant materials, sealing materials, coatings, and other high-temperature protection applications. For fire-resistant materials in new energy battery packs, we can match appropriate products based on the customer’s application method, target expansion ratio, and particle size requirements, and provide product specifications and technical documentation.

If you are looking for a supplier of expandable graphite for fire-resistant and thermal insulation materials in battery packs, please feel free to contact us to discuss your specific applications and product requirements in further detail.