Bosch drives development of both batteries and fuel cells
To power a midsize electric vehicle, the battery should provide a usable electric energy content of 50 kWh. Today’s lithium-ion batteries typically feature energy content of some 30 kWh – at a weight of 230 kilograms. To achieve the goal of 50 kWh, the battery would come to a whopping weight of 380 kilograms. Bosch said its goal is to create a 50 kWh battery that weighs only 190 kilograms. At the same time, the researchers hope to be able to significantly reduce the charging time; the goal is getting 75% of the energy content into the battery in less than 15 minutes. The company conducts its research activities in a joint venture with GS Yuasa and the Japanese carmaker Mitsubishi.
A breakthrough could come however not from the Far East but from California: Bosch recently acquired Californian company Seeo Inc. The startup company has developed a technology that could well help to drastically increase the power/weight ratio of the batteries: It helps to increase the number of lithium ions in a given space by replacing the graphite in the anodes by metallic lithium. Such batteries will have an additional advantage: They do not need a liquid electrolyte anymore. For this reason, they would do away with the risk of ignition. Bosch’s goal: by 2020, the batteries will have at least twice the capacity. But first the company will have to invest in R&D, said Thorsten Ochs, head of Bosch’s battery technology research at the company’s new Renningen campus.
But electric mobility can be beyond battery electric vehicles (BEVs). A hot technology candidate as an alternative to batteries are the fuel cells. And Bosch already has identified a promising mobility submarket where fuel cell vehicles could be viable: Off-highway applications which includes construction vehicles, municipal vehicles, fork lifts and airport vehicles. For the latter, Bosch has provided an fuel cell control unit (FCCU). The electronics box belongs to a baggage towing tractor with electric motor. In this vehicle, a fuel cell unit is used as a kind of range extender.
The idea is based on the cognition that on airports typically more ground vehicles are in service than airplanes. They transport passengers, cargo and baggage alike, and airport operators are increasingly interested in reducing noise and exhaust emissions. The tightening of emissions legislation for internal combustion engines with more than 56 kW (EU Stage IV and US Tier 4 Final) also favours the deployment of alternative drive technologies.
The FCCU is a modified version of an existing large-series automotive hardware with all-new software. The FCCU controls the overall system with integrated hydrogen, air and coolant control loops. Bosch Engineering also was responsible for the dimensioning of the fuel cell system, based on an analysis of vehicle operation conditions, operating time, refuelling conditions and other parameters. The tests were conducted at Bosch’s in-house fuel cell lab, and along with partners Fraunhofer NAS and airport vehicle manufacturer Greening GmbH, a prototype was built that operates over eight hours without refuelling during the test. In the next step the baggage tractor will be deployed on an airport and operate under real conditions. Refuelling is not much of a problem, because in contrast to the public road network in Germany, where drivers have trouble finding a hydrogen filling stations, this kind of infrastructure is relatively common: The airports in Hamburg, Stuttgart and Munich already have a hydrogen filling station.
Bosch’s goal is implementing a complete product portfolio for the development of fuel cell drives for off-highway vehicles, said Bernhard Bihr, general manager of Bosch Engineering GmbH.