How to Select Insulating Adhesives for 800V High‑Voltage Systems? Adhesive Guide for Three‑Phase Copper Busbars, Terminals and High‑Voltage Accessories
Adhesives for 800V new‑energy‑vehicle high‑voltage systems shall focus on high‑voltage insulation, heat resistance, oil resistance, thermal‑cycling stress, terminal sealing and vibration resistance. For three‑phase copper busbars in oil‑cooled 3‑in‑1 electric drives, ELAPLUS EP 1721‑1 flexible epoxy potting compound is a key candidate. For structures requiring high Tg and low CTE, epoxy systems with high dimensional stability can be further evaluated. Three‑phase copper busbar sealing Three‑Phase Copper Busbar Sealing Why Adhesive Selection for Copper Busbars Becomes More Challenging Under 800V Systems Voltage upgrade is not the only variable. Other concurrent changes include: ■ Higher power output ■ Increased current density ■ 3‑in‑1 integrated design ■ Reduced available space ■ Adoption of oil‑cooled systems ■ Elevated operating temperature ■ Larger copper busbar dimensions Accordingly, adhesives for copper busbars need to deliver multiple functions simultaneously: insulation, fixation, sealing and stress buffering. Why Rigid Epoxies Are Not Always Suitable for All Copper Busbar Applications The thermal expansion coefficient of copper mismatches that of epoxy resins. Large‑size copper busbars generate greater absolute displacement upon temperature rise. High‑modulus materials that cannot accommodate such displacement may lead to stress concentration at: ■ Copper busbar root sections ■ Edges of potting layers ■ Terminal zones ■ Housing corners The failure sequence proceeds as follows: stress concentration → micro‑cracks → crack propagation → medium ingress → insulation risks. Therefore, flexibility has become an increasingly critical indicator for 800V copper busbar materials. Why EP 1721‑1 Is Suitable for Flexible Copper Busbar Potting ELAPLUS EP 1721‑1 is a flexible‑formula epoxy potting compound. Copper busbar sealing Primary application scenarios: ■ Three‑phase copper busbars ■ High‑voltage connectors ■ Oil‑cooled electric drives ■ Fixation at copper busbar roots ■ Protection around terminals Its core design concept: firmly secure copper busbars while reserving buffer allowance for thermal expansion and contraction. Why Oil Exposure Environment Must…
