Topology analysis of electric vehicles, with a focus on the traction battery

Abstract

Over recent years, the number of battery electric vehicles (BEVs) has drastically increased due to new European Union (EU) regulations. These regulations force vehicle manufacturers to adjust their product range in order to fulfill the imposed carbon dioxide limits. Such an adjustment enforces the usage of battery electric vehicles. However, research into the optimal BEV architectures and topologies is still in progress. Therefore, the aim of this paper is an analysis of all the current electric vehicle topologies. From this analysis, the authors identify different basic battery shapes. Subsequently, these shapes are used to describe the impact of the battery on the passenger compartment. As an initial result of this analysis, the authors create a new denomination method, via which it is possible to cluster the battery topologies. In a second step, the collected data is clustered using the novel denomination method. Finally, this paper presents the benchmark topologies for the analyzed segments.

Derivation of Geometrical Interdependencies between the Passenger Compartment and the Traction Battery Using Dimensional Chains

“…The L53-1-max value is not listed in the table because it can be calculated using Equation (4). To test the correctness of the formula, we validate it using our database.…”

“…Subsequently, we can express the L53-1-max as in Equation (4). In this equation, the lower leg length is abbreviated as Ll-l, the thigh length as T-l, the barefoot height as FH, and the distance between ankle point and AHP as BFL.…”

“…In fact, all of the three vehicles referred to above have either two or four seats. It has been shown in previous research [4] (p. 3) that, with respect to purpose design vehicles, most manufacturers (Audi, BMW, Polestar, Tesla, Volkswagen) utilize a rectangular battery placed in the vehicle underbody. Cases in which the battery is placed in the tunnel are unusual for purpose design vehicles and will not be further considered in the scope of this paper.…”

“…The central component of BEV-architectures is the traction battery, which usually represents the largest and heaviest component of the electric powertrain. In most of the existing electric vehicles, the battery is placed between the front and rear axle [4]. This position corresponds to that of the passenger compartment, thus creating an interdependency between passenger compartment and battery.…”

“…L53-1-max = cos(180° − A47 − atan(FH/BFL)) × (FH 2 + BFL 2 ) 0.5 + Ll-l × cos(A) + T-l × cos(B) (4) To reduce the number of inputs, the ankle angle (A46) can be set to 87° according to [25, p. 30]. Furthermore, it is possible to approximate the pedal angle A47 with the H30-min.…”