Last two weeks I’ve been working on the layout of the Relays Box at Nova Electric Racing. The Relay Box makes sure that the high voltage circuit of the batteries can be interrupted at all times. This is mainly used in case of emergency, but is also useful during charging. Since the relays interrupt the battery pack in the middle, two lose battery modules of 350V are created. Theses lower voltage modules can be charged with our power converter. The relays are switched by the Safety Control Unit when charging or when the temperature rises to much (there is a blog on the Safety Control Unit).
Next to the relays our Relay Box contains other safety measures as well. The box is equipped with an Aerosol Fire Extinguisher. This extinguisher fills the entire Battery Pack with an aerosol in case they catch fire. The system has an electrical and a mechanical activation mechanism. Electrical activation is done by a heat sensor in the middle of the battery pack, while the mechanical activation mechanism
The challenge of designing the relays box is to make it as compact as possible. This due to the fact that the box will be placed in front of the battery pack and we have to prevent it from hitting the radiator or the front wheel when the front suspension is compressed.