PRESS RELEASE
Automobile manufacturer again puts its trust in Fronius Active Inverter Technology
Super-efficient battery charging technology
(Wels, Austria) A Bavarian automobile manufacturer has invested nearly half a billion euros in
production facilities for its new volume model at its headquarters in Bavaria. A small but substantial
part of this investment was spent on installing a central charging station in the bodywork shop for the
batteries of more than 100 electric forklift trucks. New approaches to construction were also adopted
during this process.
The big day was Saturday, February 11th 2012, when the sixth generation of the BMW 3 Series was launched
simultaneously across international markets. "The BMW 3 Series is the BMW Group's most important volume
model and a best-seller across the entire premium segment," emphasised Frank-Peter Arndt, member of the
BMW AG executive board and responsible for production, marking the start of series production of the new
limousine on October 28th 2011 in the main factory in Munich. Within three months of the new vehicle going into
production, peak levels of 680 units a day had been reached. This means the factory is now manufacturing
more than 900 vehicles a day.
Highly efficient production in new bodywork shop
Between 2009 and 2012, the BMW Group invested nearly half a billion euros in Munich for the production of the
new series. The investment went into several areas, including new manufacturing facilities. A large, modern
press, which processes 600 tonnes of steel a day, is used in the manufacture the new car.
To facilitate production of the new BMW 3 Series, a completely new production hall was erected over the old
bodywork building, which was too low. The old building was then gradually dismantled. A new logistics centre
for vehicle assembly has also been established. Rebuilt and extended production lines and numerous forklifts
help integrate the individual areas into the production flow. Of the 800 forklifts in Munich, approximately
400 consist of electrically powered stackers, tiller-controlled pallet trucks and tractors. As a result, numerous
centralised and decentralised charging stations are scattered around the site to supply the traction batteries
with the required energy.
To prevent the electric vehicles from losing valuable time and energy travelling the long distances to and from
the charging stations, an additional charging station was installed to service the 104 electric vehicles used by
the bodywork shop in building 35. It went into operation in January 2012. The bodywork stacker drivers travel to
this centralised station to change the battery when the residual battery capacity reaches approximately 20%.
The drivers change the batteries themselves: A roller shutter opens and a small overhead crane, to which
different types of lifting gear can be attached for the various battery types, is used to remove the lead acid
battery, which can weigh up to 2.2 tonnes, and places it on an empty charging station. Once this battery is
connected to the charger, the driver attaches to the crane the battery that has been waiting the longest since
charging, takes it to his stacker and inserts it.
A first: the two-part charging station
The new charging station in Building 35, fitted out by Austrian battery charging systems specialist Fronius, uses
an innovative concept: the stations for charged batteries and batteries that need charging are on the ground
floor, while the associated chargers are located directly underneath in the basement. This arrangement has
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several advantages. The space containing the batteries is more compact and seals the working environment off
from the oxyhydrogen produced during charging. Furthermore, the chargers cannot be damaged by batteries
that are attached to the crane hook that may swing out.
The battery room is currently designed to accommodate 30 charging stations. The number of stations depends
on the types of battery to be charged and their size. The electric vehicles are fitted with 24, 48 and 80 V
batteries with capacities of between 120 and 700 Ah. According to statements from BMW, a further 12 to 15
existing areas are to be converted to charging stations this year.
The battery room is equipped with safety devices that exceed the requirements set out in the legislation. BMW
therefore well exceeds the mandatory fivefold levels of air circulation. The room also has a hydrogen detector. If
increased hydrogen levels in the air are detected, and hence the risk of oxyhydrogen development, the shutters
and a fan removes the gas from the battery room. In the worst case scenario, the control room receives a
message and can disconnect the chargers completely from the mains as an emergency measure.
Latest charging technology for cost conscious users
The charger room in the basement contains the latest intelligent battery charging technology. The 25 chargers
are all from the "Fronius Selectiva Plus 8140" series and have a nominal charging voltage of 80 V and a
charging current of 100 to 140 A. They are suitable for batteries with capacities of between 120 and 1700 Ah. A
special feature is the "Active Inverter Technology" from Fronius. The extremely high efficiency level of 94%
reduces energy costs dramatically (by up to a third) compared with the old transformer technology and
conventional HF devices. Efficiency levels with the other technologies mentioned varies between a modest 70%
and 90%.
The advantage of very gentle charging with Active Inverter Technology means that the service life of the
batteries can be extended by as much as 25%, another significant saving. This is possible because Fronius
technology is based on a combination of a digital control circuit, dU/dt technology, and a charging voltage with
negligible residual ripple. Active Inverter Technology saves on space and weight as well. The Selectiva Plus
8140 devices in the new BMW charging stations weigh just 40 kg and have compact dimensions of 625 x 290 x
480 mm (L x W x H), so do not take up too much space.
Another advantage of the Selectiva Plus 8140 chargers proved particularly attractive to BMW: in addition to the
80 V batteries, smaller 12, 24, 36, 48 and 72 V batteries can also be charged. Various characteristics allow the
charge to be optimised to suit the requirements of the application. This ensures that the entire battery spectrum
in this BMW area is covered. Remarkably, Selectiva chargers can also charge single cells. This is particularly
helpful to service personnel when targeting faulty individual battery cells or charging newly installed ones.
Additional Fronius chargers from the Selectiva Plus range are to be installed in the basement as part of the
aforementioned extension of the charging station planned for later this year.
Remote-controlled battery charging system
The chargers in the basement can be controlled remotely from the battery room on the ground floor. Optimum
charging characteristics can be programmed easily on displays located above the batteries. The large green
displays above each charging station really stand out in the battery room. They show the time that has elapsed
since charging ended: shortly before charging ends, an integrated clock starts, the display begins to light up and
this tells the stacker driver which battery to remove first, as it will be the battery that has had a full charge the
longest and has now cooled down sufficiently.
The battery charging system was developed by an external engineering consultancy in close collaboration with
Fronius. The battery charging system specialist supplied vital parameters such as amperage, size of the
connection cable and calculations for the battery charging room with respect to ventilation. It goes without
saying that the many years of experience of the specialists from the automobile manufacturer also went into the
planning. It is this experience that resulted in Fronius charging technology becoming the most widespread
technology in use at BMW – and not just in Munich. "We had to learn the hard way with chargers from other
manufacturers", is how BMW put it. It was stressed that Fronius charging systems, by contrast, work for ten
years and more without any problems.
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Characters: 6,914 without spaces
Author: Wolfgang Degenhard
Some photos
Photo 1
The new BMW 3 Series is built in the new bodywork shop in Munich
(Photo: BMW)
Image file: Fronius_BMW_01.jpg
Photo 2
In the charging station (from l. to r.): Marlon Rönnecke (Fronius, Germany), Martin
Hofmüller (BMW, Munich), Alen Postenik (BMW, Munich)
(Photo: Fronius)
Image file: Fronius_BMW_02.jpg
Photo 3
The stacker driver loads and unloads the charging station using a small overhead
crane
(Photo: Fronius)
Image file: Fronius_BMW_03.jpg
Photo 4
To the side, the charger remote control units, on the wall, the green status displays
(Photo: Fronius)
Image file: Fronius_BMW_04.jpg
Photo 5
A tidy and compact line-up in the basement: the "Selectiva Plus 8140" chargers
with Active Inverter Technology
(Photo: Fronius)
Image file: Fronius_BMW_05.jpg
Reproduction: free of charge
Internet sites of the companies mentioned:
BMW AG: www.bmw.com
Fronius Battery Charging Systems: www.fronius.com/intralogistik
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About Fronius International GmbH
Fronius International GmbH is an Austrian company with headquarters in Pettenbach and other sites in Wels,
Thalheim, Steinhaus and Sattledt. With 3,257 employees worldwide, the company is active in the fields of
battery charging systems, welding technology and solar electronics. Around 94% of its products are exported
through 19 international Fronius subsidiaries and sales partners/representatives in over 60 countries. With its
innovative products and services and 878 active patents, Fronius is world technology leader.
Enquiries: Boris Ringwald, +43 664 60241 6436, ringwald.boris@fronius.com
Copies: Boris Ringwald, Froniusplatz 1, 4600 Wels, Austria
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