An e-kit for all cases

From microcars to SUVs and light commercial vehicles: With its modular platform for battery electric vehicles, IAV demonstrates how electric drives can be developed cost-effectively and consistently tailored to the technical and market-specific requirements of vehicle manufacturers and suppliers. Components such as batteries, battery management systems and inverters are also on offer.

The success of e-mobility depends crucially on customer acceptance. In addition to comfort, performance and sustainability, costs also play an important role. This is where IAV comes in: “We asked ourselves whether a single battery-electric drive platform could cover the wishes of customers and the requirements for an entire fleet of e-vehicles (Battery Electric Vehicles, BEV) – from small vehicles to compact and mid-size cars to large SUVs and light commercial vehicles,” says Rene Kockisch, Team Leader System Development Mechanics at IAV.

“To do this, we used our in-house developed tools IAV Powertrain Synthesis and IAV Platform Optimizer. The latter allows us to find the best possible grid for components such as e-machines, gearboxes and power electronics so that as many identical parts as possible are used throughout the fleet.”

As a starting point for the development of the BEV platform, IAV defined the characteristics and performance features of six e-vehicles.

These include a compact car weighing 1,200 kilograms, with a range of around 380 kilometers and a maximum speed of 180 kilometers per hour, and a mid-size sedan weighing 1,700 kilograms, with a maximum range of 500 kilometers and a top speed of 225 kilometers per hour. The light commercial vehicle weighs 2,500 kilograms, has a maximum range of 250 kilometers and reaches up to 160 kilometers per hour. “These are not fictitious values – rather, they correspond to customer:internal expectations and, in many respects, to the characteristics of vehicles already on the market as well as those under development,” Kockisch emphasizes. “We have also taken into account operation with a trailer, because that is important for many customers.”

24 million possible configurations examined

After passing through the powertrain synthesis and platform optimizer, a spectrum of three vehicle topologies (front-wheel, rear-wheel and all-wheel drive), three transmissions with one or two gears, ten e-machines with 100 to 220 kilowatts of power and 200 to 350 Newton meters of torque emerged. In addition, five inverters with three or five phases based on silicon carbide MOSFETs or silicon IGBTs (Insulated Gate Bipolar Transistor). The five battery variants have capacities ranging from 42 kWh to 115 kWh and operate at different voltage levels. Around 24 million powertrain configurations have been investigated for the BEV platform.

«With the resulting modular kit, we can cover the requirements of the entire fleet we have defined. Within the vehicle classes, we can also vary - for example, in the case of the SUV from the low-cost solution to the high-performance version.»

Rene Kockisch — Team Leader System Development Mechanics at IAV

The core properties defined at system level on the basis of powertrain synthesis were followed by intensive work on the powertrain components from layout through design to optimization, in which IAV was able to draw on many years of experience. With the help of this development expertise across the board, it was possible to implement effective development of the entire electric platform and to transparently present conclusions and effects at system level at all times.

The BEV platform has been available since mid-2020. “We are already talking intensively with customers who are either interested in subsystems such as the e-machine or transmission or are looking for solutions for their second- or third-generation electric powertrains,” reports Kockisch. “With our systematic approach and tools, we can also take a manufacturer’s individual requirements into account by building on our BEV platform or by going through the entire process anew with its specifications. In doing so, we can accompany customers* from the beginning as well as keep an eye on his*her entire platform.”

70 kWh - 670V - battery with active fluid cooling

150 kW - 800 V - 2 speed - EDU

Batterien mit Ökodesign

With its modular BEV platform, IAV has defined a basic structure and at the same time created the basis for further developments. As part of the development process, sub-platforms were created for the battery, power electronics, e-machine and transmission, which are coordinated with each other and ready for use across the entire fleet. A spectrum of drive systems for 400 volts and 800 volts with system outputs ranging from 100 kW to 440 kW is used. Based on these basic structures, IAV experts are working on new solutions to meet the diverse requirements of the e-vehicles of tomorrow and beyond.

“We are currently building modular power electronics,” says Kockisch. “A dedicated IAV battery management system already exists, but we also see great potential here in terms of sustainability.” While energy storage systems are currently mostly designed to last only one lifetime, eco-design that reduces a product’s environmental impact over its entire life cycle is likely to be in demand in the future. “We are working on new batteries of this type,” says Kockisch.

The article appeared in automotion 02/2021, IAV’s automotive engineering trade magazine. Here you can order the automotion free of charge.

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