The requirements of a Daimler subsidiary such as EvoBus on an in-house supplier such as AKASOL and its products are extremely high. Battery systems for the eCitaro, the first electrified bus by the market leader based in Mannheim, Germany, had to be robust, durable and quick-charging. At the same time, they had to provide the range expected by Daimler customers and supply energy to additional units such as air conditioning and electrical systems.
In 2015 cooperation between EvoBus and AKASOL began with the development, testing and validation based on the AKASYSTEM OEM battery system. The focus was always on meeting the high demands placed on one of the most important components of the electric powertrain with the aim of being able to start series production of the battery systems. AKASOL’s nearly 30 years of experience with battery systems for electric vehicles stood it in good stead.
eCitaro Generation 2018:
The first generation of the eCitaro is launching at the end of 2018. Six to ten batteries of the AKASYSTEM OEM type with a total capacity of up to 243 kilowatt hours will be installed both on the roof and in the rear of the electric bus. The battery systems use lithium-ion battery cell by Samsung, which were jointly selected by AKASOL and EvoBus. Efficient water-cooling, which guarantees stable tempering at 25 degrees, is essential for meeting the bus’s life expectancy.
The eCitaro of the first generation enters the market with a reliable, year-round range of 150 kilometers, based on SORT2 cycles in medium-heavy city traffic. Under ideal conditions, the eCitaro’s range is already 200 kilometers.
“It was a great challenge for our company to meet Daimler’s high requirements on one of the most important components of electric power trains." Sven Schulz, AKASOL CEO
eCitaro Generation 2020:
In summer 2018, even before series production of the battery systems for the first generation had started, AKASOL began developing the next generation. In addition to improved battery cells that fit in the same space as the first generation, many other small optimizations, for instance in the battery management system and the mechanical architecture, contribute to the improvements of the second-generation systems
The second generation of the eCitaro will launch in 2020. Its battery systems offer 35 percent more energy. Installing the improved battery packs is possible due to the identical spatial design of the battery systems (upward compatibility). Instead of the initial 25 kilowatt hours of storage capacity per battery pack, the second generation will be able to store 33 kilowatt hours per pack. This means an increase of 35 percent per vehicle from up to 243 to up to 330 kilowatt hours - in the same space and with the same weight. Thus, the range increases to 200 kilometers in S0RT2 and up to 250 kilometers under ideal conditions.
The high-performance battery systems are manufactured in Langen, in Europe’s largest factory for commercial vehicle batter y systems, which AKASOL officially opened at the end of 2017. The production facility has an annual capacity of 300 megawatt hours. Series production finally started in the fall of 2018.
Pictures: Copyright Daimler AG - Product Communications Daimler Buses