Thermally Conductive Battery Adhesive for Hybrid Vehicles from DELO


Thermally conductive adhesive (magenta-colored for illustration) for low-voltage battery systems such as those used in mild hybrid vehicles (figure: DELO)

DELO, one of the world’s leading manufacturers of industrial adhesives for automotive, consumer and industrial electronics applications, now offers a structural adhesive for batteries used in hybrid vehicles. Designed for high-volume series production, DELO-DUOPOX TC8686 is thermally conductive and flame-retardant.


Already being used by an automotive supplier in the ramp-up phase of production, this new adhesive is suitable for low-voltage batteries found in mild hybrid and conventional hybrid vehicles, as well as in e-bikes and e-scooters. The adhesive allows battery cells to be bonded into a battery’s housing while dissipating the heat generated during operation.

Instead of mechanically connecting the battery cells and then using gap fillers for heat dissipation, DELO-DUOPOX TC8686 combines connection of the thermal management system and structural bonding into one step, simplifying production.

Adhesive properties optimized for batteries

DELO-DUOPOX TC8686 is designed for temperatures ranging from -40 °C to +85 °C and offers good strength on battery cells and typical housing materials. The tensile shear strength of the adhesive on aluminum is 18 N/mm² and meets the strength requirements of the automotive industry at typical operating temperatures ranging from 10°C to 40 °C as well as at maximum service temperatures of 80°C. Temperatures beyond this can result in irreversible damage to the battery electrolyte. The adhesive's elongation at tear also helps to meet these requirements. A certain flexibility compensates for the different thermal expansion behaviors of cell and housing material during operation.

The adhesive has a thermal conductivity of 1.1 W/m*K. It also meets the requirements for flame retardancy according to UL 94 V-0.

Developed with a view to high-volume series production

DELO-DUOPOX TC8686 has been optimized for manufacturing processes. It offers a simple mixing ratio of 2:1 and has a processing time of approximately 30 minutes after mixing. This is long enough for prototypes and small series and fast enough for fully automated systems. After four hours, the adhesive reaches its initial strength. Ninety percent of its final strength can be achieved after 24 hours. Even with low heat input, this amount of time can be reduced significantly. Depending on the battery electrolyte used, a curing temperature of 60°C can help to speed up assembly.

Beige in color, the product is easily detectable by cameras, ensuring accurate application control. In addition, the filler for thermal conductivity is only slightly abrasive, contributing to the dispensing systems' long lifespan. The product is classified in transport category 1. It is easy to transport and can be stored at room temperature.

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