In the field of electric power engineering usually it is not sufficient, if a problem is investigated from a single viewpoint only. The purpose of this paper is the design of a composite accumulator container, which must satisfy many, sometimes contradictory safety criteria. The battery container is a significant part of the power system in a hub motored Formula Student racing car. The design rules were given by the specifications for batteries of the Formula Student rules. This container system is optimized for mechanical, insulation technical and flammability criteria.
One of the most important viewpoints during mechanical design is the materials selection. In the investigated case several material test were needed in order to select proper polymer composite material and flame retardant. For mechanical material characterization tensile tests and three-point bending tests were carried out. Moreover insulation resistance and flammability tests were performed too. The flame resistance of a composite material is assured by the added flame retardant, which weakens both the insulation and mechanical properties. The flammability test was carried out according to the UL94 standard. On the other hand the conductivity of the composite was tested by insulation resistance measurement.
During the construction both the arc formation possibilities and manufacturability issues had to be taken into account. In order to understand the behaviour of the electric arcs emerging from short circuits, we investigated several arc models. Based on the foresaid issues, the conformity of the geometry design was tested by measurements. In the investigation of manufacturability a custom manufacturing technology was chosen, and an applicable dye was designed. As an ultimate result based on the preliminary tests and calculations, the accumulator container system satisfies the regulations implied in the competition rules.