FEV GmbH to show advanced battery solution at Vienna Motor Symposium

Compact, scalable battery system provides same power / energy requirements of larger units

Aachen, 26. April 2012 – FEV GmbH, (FEV) a leading developer of advanced powertrain and vehicle technologies based in Aachen, Germany, announced today that it will exhibit its FEVeesy Battery Technology at the 33rd International Vienna Motor Symposium, 26 - 27 April 2012 at the Congress Center Hofburg, Vienna. The announcement was made by FEV GmbH president and CEO Prof. Stefan Pischinger.

“Market forces are driving the expansion of the electric and hybrid or plug-in electric market, thus creating the need for multiple battery solutions, ” said Prof. Pischinger. “FEV has developed a battery solution combining energy and power that can, because of its scalable configuration, be adapted for many different vehicle platforms.”

FEVeesy
FEVeesy is a combination of power and energy cells connected by a cost efficient
current controller. The demonstrator was created as a solution for Plug-In-Hybrids with high power demand in charge sustaining mode and to maintain sufficient energy content during charge depleting mode. FEVeesy offers many advantages in packaging, weight and cost as compared to conventional plug-in batteries with the same power and energy requirements. FEVeesy is also scalable, with the ability to add additional energy modules, thus increasing driving range. There is no separate cooling of energy modules necessary due to the low charge and discharge rates.

The system, development of which was funded through the Bundesministerium für Wirtschaft und Technologie, is packaged with a battery management system, precharge box and the energy and power modules. FEV was responsible for the complete development of the system, including layout, design, assembly, and testing.

Battery Management System
At the heart of the FEVeesy is the battery management system (BMS). Made up of several components, the BMS regulates both power and energy levels based on state-of-charge (SOC) level. Making up the BMS are:
•Slave Control Unit – monitors voltage and temperature of up to twelve LI battery cells, allowing for a power supply to be taken directly from attached battery cells. Its 500 kbit/s Can-bus is commonly used in automotive applications, and there is full galvanic isolation between measurement and communications interfaces, full redundancy in cell voltage supervision, and the unit is adaptable to a variety of battery topologies, include serial / parallel up to 500V maximum.

•Multi String Manager – The Multi String Manager (MSM) is used to safely interlink two parallel battery strings. High-voltage contact is controlled and monitored, especially important during battery start-up when fast and precise measurement of the individual string voltages is essential.

•Isolation Monitor – The Isolation Monitor (IM) is a control device to measure and monitor the isolation resistance between high voltage potential and vehicle ground. In the event of mechanical damage, moisture, etc., and isolation fault can pose significant danger. Thus, for safety reasons, it is essential that there is central and / or distributed monitoring of insulation to prevent failure.

•CaMPuS – the FEV CaMPuS is an extension board for use with the FEV BMS Master. The CaMPuS combines a variety of analog and digital I/Os with a CAN-data logger to monitor and log battery operating conditions.

Energy and Power Modules
The energy and power modules are compact by design, but also retain the ability to be expanded in order to extend electric driving range. To extend driving range, additional energy modules can be added.

The energy module, weighing just 48 kg with a volume of 30L, contains 96 cells and has an energy density of 241 Wh / Liter; 152 Wh / kg, and a power density of 266 W / Liter; 166 W / kg.

The Power module has 192 cells with maximum power (10s) fo 80 kW, and (1s) 120 kW. The module weighs 34 kg and has a power density of 3,750 W / kg (3,529 W / Liter) and an energy density of 100 Wh / kg (94 Wh / Liter).

Power flows to and / or from the energy module and power module via a current controller, with a current limiter that tries to equalize the SOC levels of both modules.

High-voltage interface to the vehicle is accomplished via the Precharge Box (PB). The PB not only allows for the precharge of the electrical functions of the vehicle, but it can safely be disconnected to prevent injury and / or damage. The 12V vehicle power supply can be integrated into the battery for packaging, and is easily connected to the PB.

The FEVeesy system provides a low cost, easily packaged alternative to manufacturers of plug-in hybrid vehicles, which should be an attractive option as this type of vehicle proliferates.