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AUTOMOTIVE AUTOMOTIVE

WIRED BATTERY CONNECTIONS: THE DISADVANTAGE OF A WIRED BMS
THE COSTLY, HEAVY, AND COMPLEX However, there is also a list of disadvantages related
APPROACH to wires: A copper wiring harness adds additional
The intention for the wBMS technology development weight and occupies space that, if filled by a battery
was based on an analysis of the drawbacks of the cell, would provide extra energy capacity. Additionally,
communications wiring in today’s conventional EV the wiring needs to be fastened on battery housing
battery packs. This analysis drew on ADI’s expertise: structures and connectors can potentially suffer from
It supplies the market’s most accurate BMS ICs in the a mechanical failure, especially under vibration and
wireless communications field. ADI also developed the shock conditions.
world’s most robust mesh networking technology for
industrial environments. In other words, wires increase development effort,
manufacturing cost, and weight while also reducing
In a conventional EV battery pack, each cell is mechanical reliability and usable space. This results in
measured by a battery management IC. Data from the reduced driving range. By removing the wiring harness,
battery management IC is then communicated back the car manufacturer gains new flexibility to meet a
to the pack ECU through wiring. This requirement vehicle’s design requirements for the form factor of its
for communications inside the battery reflects the battery pack.
complex architecture of a large battery pack: It is
typically made up of modules, each of which contains makes the assembly of a battery pack difficult and
The complexity of a battery’s wiring harness also
multiple cells. Natural production variations mean
Wireless BMS Enables that each cell has individual characteristics that vary expensive: Wired packs must be assembled and the
within a specified tolerance range. To maximize battery
connections must be terminated manually. This is a
Smart Battery capacity, lifetime, and performance, the key parameters costly and hazardous process because high-voltage
EV battery modules are supplied charged. To maintain
of battery operation — voltage, charge/discharge
the safety of the assembly process and to protect
current, and temperature — need to be monitored and
Ecosystem Solutions logged individually for each module. production-line workers, rigorous safety protocols are
applied.
This is the reason why an EV’s battery requires a
means to transfer data from each module or cell, Out of those reasons, there are then strong reasons
By Stephan Prüfling, product manager for battery management systems at AVL, and where voltage and temperature are measured, to for OEMs to introduce a robust wireless technology in
the ECU processor (see Figure 1). Traditionally, these
new EV battery system platforms.
Norbert Bieler, director of business development for e-mobility at Analog Devices, Inc. connections have been made with wires: Wired
connections have the advantage of being familiar and wBMS: A NEW SMART APPROACH
Electrification of passenger cars and commercial Out of this demand, news about battery innovations well-understood. The wBMS is a complete solution that is easy for the
vehicles is entering a new phase of market tends to highlight the new battery packaging concepts automotive manufacturer to integrate into a battery
penetration. The shift away from technology feasibility and new materials that might one day be able to
demonstration to the mass production of premium store more charge than today’s lithium technology. A
vehicles is obvious. The commercialization of different part of the battery — the battery management
technology leads to more optimized and affordable system (BMS), which monitors the state of charge
vehicles. (SOC) and state of health (SOH) of the battery — tends
to go under the radar but needs to follow and support
Nevertheless, most current-generation electric battery innovation.
vehicles are still considered to be expensive or
less attractive when compared with conventional Here, the new wireless BMS (wBMS) technology,
combustion-engine cars. Consequently, cost reduction developed by Analog Devices Inc. and pioneered by
and improved performance are key to ensuring a General Motors in its modular Ultium battery platform,
successful and sustainable market growth. Reductions is now in mass production. The wBMS gives car
in size, weight, and cost impact the competitive edge manufacturers a new competitive edge across the
of battery systems over a vehicle’s complete life cycle. whole of a battery’s life — starting from when battery
On the other hand, the extension of the driving range modules are first assembled to operation in an EV to
will also have a significant impact on their market disposal and even, if needed, into the battery’s second
attractiveness and competitiveness. Furthermore, as life.
the increasing numbers of EVs reach the end of their
life, car manufacturers will even be competing for
the value to be derived from second-life batteries
recovered from scrapped vehicles. Figure 1: A typical multicomponent wired BMS network (left) and the simpler arrangement made possible by wBMS technology (right)

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