Potting of high-voltage batteries: New system solution
1 liter worth of Gap Filler in 13 seconds
The application of thermally conductive materials is often a bottleneck in production – especially in the automotive industry with its highly automated manufacturing processes. A new system solution especially developed for the encapsulation of high-voltage batteries now addresses and resolves such bottlenecks.
The heart of electric vehicles is the built-in high-voltage battery. Thermal influences have enormous effects on its service life, capacity and especially its operational safety. Very high temperatures can cause internal short circuits and in the worst case lead to severe and even irreparable damage to the high-voltage battery and vehicle. To prevent this from happening, large quantities of heat-conducting paste are used. Due to their high viscosity and the high proportion of abrasive fillers, however, the application of these materials poses a challenge. Besides, thermally conductive pastes often only allow relatively low dispensing speeds. As a result, this process step often proves to be a bottleneck in fully automated production processes, as they are the norm in the automotive industry.
Scheugenpflug has developed a new complete solution specifically for the encapsulation of high-voltage batteries. The system, consisting of the high-performance dispenser Dos HP and the PailFeed200 Abrasive material feeding system, allows dispensing rates of up to 80 ml/s even when using highly abrasive thermally conductive materials. The all-in-one solution has been designed for easy operation and maximum robustness. Users thus benefit from simple and fast maintenance, long service life and significantly reduced maintenance costs. Optionally, it is possible to connect two feeding systems in parallel with the dispenser. This allows continuous system operation without downtimes when potting high-voltage batteries.
The PailFeed200 Abrasive, which has been designed for 200 l barrels, ensures the fast and reliable transfer of heat-conducting material to the dispenser. The robust follower plate pump has an integrated double piston pump with a delivery volume of 480 cm3/stroke, which allows for a continuous material feed. Thanks to the high delivery pressure of 65 bar, a high delivery rate is guaranteed – even when using highly viscous and highly filled thermally conductive pastes. The feeding system offers long service life, as the pump only comes into contact with the potting material on one side. The rear side contains a barrier fluid, which prevents the accumulation of abrasive fillers on the seal and pump components.
1 Liter in just 13 seconds – that’s how much Gap Filler the newly developed Dos HP high-performance dispenser can process. It allows fast and precise application of thermally conductive media with a viscosity of up to 1,000,000 mPa·s and a maximum volume per shot of 310 ml. Two powerful electric motors in the dispensing unit ensure the required performance. To meet the necessary stability during material application, the mixing tube is reinforced with an additional metal sleeve.
The Dos HP is typically mounted to a robot arm to ensure a sufficiently large traversing range for potting high-voltage batteries. The new high-performance solution is based on the system technology of the volumetric piston dispenser Dos P. It has been upscaled and optimized especially for the discharge of very large material volumes in a short time. Similar to its smaller sister systems, operators of the Dos HP benefit from the system’s long service live, simple and fast maintenance and thus considerably reduced maintenance costs.
Like the Dos P, the new high-performance dispenser features precisely dimensioned dispensing cylinders that allow for the discharge of precise and reproducible material volumes. In the case of two-component materials, the parallel emptying of both cylinders into the joint mixing tube also ensures a constant mixing ratio at all times.