Thermally conductive battery adhesive for hybrid vehicles

DELO has introduced a structural adhesive for batteries employed in hybrid vehicles. Created for high-volume series production, DELO-DUOPOX TC8686 is thermally conductive and flame-retardant. The product is being employed in the ramp-up of an automotive supplier.

The new adhesive is especially ideal for low-voltage batteries which are found in mild hybrids. This enables, for example, battery cells to be bonded into the battery housing while also efficiently dispersing the heat generated during operation.

The adhesive blends structural bonding and connection of the thermal management system in one step rather than mechanically connecting the battery cells and then utilising so-called gap fillers for heat dissipation. This saves one process step and makes production simpler. The product is not only ideal for mild hybrids, but also for conventional hybrids and other batteries in the low-voltage range, including those employed in e-bikes and e-scooters.

The adhesive is created for temperatures ranging from -40C to +85C and provides good strength on battery cells and typical housing materials. For example, the tensile shear strength on aluminium is 18N/mm2. The adhesive also satisfies the strength demands of the automotive industry at typical operating temperatures between 10C and 40C up to the maximum service temperature of 80C, a temperature at which the battery electrolyte can already be irreversibly damaged.

The product's thermal conductivity, which is a particularly important factor for battery cell applications, is 1.1 W/m*K. It meets the requirements for flame retardancy according to UL 94 V-0.

The adhesive provides a simple mixing ratio of 2:1. It has a processing time of around 30 minutes after mixing. After four hours, the adhesive reaches its initial strength: 90% of its final strength can be delivered after 24 hours.

Beige in colour, the product is easily detectable by cameras, assuring accurate application control. Also, the filler for thermal conductivity is only slightly abrasive, adding to the dispensing systems' long lifetimes.