Stäubli has sponsored this post.
E-mobility, or the electric vehicle industry, continues to grow across segments—from consumer cars to commercial fleets and even industrial and agricultural vehicles. However, in some ways the electric vehicle began life looking a little like “a hammer without a nail,” a phrase coined to describe an emerging technology that provides a valuable solution, but which has yet to find the key application that will empower it to grow and scale into a large industry.
The electric drivetrain is not a new invention. In fact, the first electric car was developed in 1890, just four years after the patent for the Benz Motorwagen, commonly regarded as the first automobile. For a decade, electric vehicles were real competition for internal combustion engines. Today, the engineering story has come full circle, with recent advances in battery and motor technology that have unlocked the potential of the electric drivetrain, allowing electric solutions to make inroads into many mobility markets, including automobiles. A major part of the new Renaissance in e-mobility is a holistic systems approach to drivetrain engineering. Everything counts, down to the smallest component.
To learn more about the technology that drives e-mobility and some of the important applications, engineering.com spoke with David Rababy, Head of Sales, eMobility, North America at Stäubli and John Risso, Field Sales Engineer in Stäubli’s e-Mobility division.
Stäubli’s e-Mobility Technology
Stäubli is well-known for its MULTILAM high-power contact technology, which is used in demanding electrical applications in industries including power transmission and distribution (aka the grid), robotic welding, railway, photovoltaic solar and now eMobility. With specialized geometry and materials, the MULTILAM torsion spring contacts operate with minimal electrical resistance and therefore maintain high conductivity under extreme current loads, with excellent heat management and durability. For e-mobility, Stäubli has adapted this technology into PerforMore, a connector that can reliably meet the requirements for high-voltage connections and connectors in vehicles defined in the LV 215 automotive standard. As a two-pole angled version, it can be used with high-voltage batteries, inverters, motors, cable harnesses and high-voltage distribution units (HVDUs).
Electricity is the same, regardless of its application, but the operating environment and safety requirements of motor vehicles are significantly different from fixed power supply and distribution systems. LV specifications, which are supply standards for OEMs developed by a consortium of German auto manufacturers, reflect the severe service nature of the automotive industry, including performance standards measured over the service life of the vehicle.
A typical specification would be full functional capability for at least 15 years, or 8,000 hours of operation and 30,000 hours of charging, or at least 300,000 kilometers of road use for passenger cars. A typical truck specification may be 15 years and 1,000,000 kilometers of driving. Connectors built to this standard must perform over typical vehicle lifetimes with unknown and potentially severe climatic and service conditions. It’s a tough standard, especially where high voltages are present.
The PerforMore connector is designed for compact dimensions, while maintaining all the clearances and creepage distances required for high operating voltages. The system is used in different interfaces along the drivetrain. In the mated condition particularly, the PerforMore’s low height offers a clear advantage, allowing more efficient use of the installation space available in vehicles.
The connector is IP68 and IP6K9K tested according to IEC, rating 60529 in mated condition and IP2X in unmated condition. It also has resistance to vibrations and high operating temperatures, such as those encountered in fleet vehicles and heavy equipment.
The safety and reliability of these connectors is paramount in e-mobility, including ingress and touch protection. In addition, connectors must be safe, especially as electric vehicles demand higher voltages and currents to offer faster charging.
“Because of the MULTILAM technology we’ve put into PerforMore, as people are starting to put more power through that contact,” says Risso.
The PerforMore connector is designed for a continuous 400-500 A, at 1,000 V.
e-Mobility Applications
According to Rababy, while electric passenger automobiles need to contend with charging infrastructure on routes across cities and on longer journeys, closed-loop vehicle fleets such as municipal buses don’t face this issue, as they can rely on a central hub to provide power and work in a predictable range.
“I think for commercial vehicles those smaller fleets in a smaller area are going to electrify first, and then public infrastructure—similar to what we have today where every vehicle works at every gas station—will appear in the longer term,” says Rababy.
“Utilities and municipalities and other industries that have a fixed route or a fixed field that they're working in—they can control a lot of the variables,” adds Risso.
Because these fixed-purpose vehicles can accurately predict the required range needed for a shift, operators can easily plan charge time.
“For example, while an operator would be sitting idling, wasting diesel fuel, waiting for a shipping container to be unloaded at a port, they could take advantage of that time and visit a charging station for ten minutes,” says Risso.
In addition, municipal buses benefit from some of the other advantages of the electric drivetrain. “One driver for municipalities was the air quality and also the pollution—not only air pollution, but noise pollution. They wanted to be quieter at nights in urban areas, close to where people are sleeping,” says Rababy.
SOR, a Czech manufacturer of environmentally-friendly buses, required a connector for its new SOR NS all-low-floor electric bus. This bus design allows for various seat layouts and entrance door combinations, offering greater flexibility. In addition, the bus is designed for low-cost operation and maintenance. Powered electrically, the bus also operates quietly and without emissions.
However, the low floor design of the NS bus limits space for technology, including wiring harnesses under the passenger surfaces. To aid with low-cost maintenance, SOR engineers specified a pluggable connector to connect the batteries to the charging socket cabinet. This two-pole connector would also need to serve loads up to 400A/1,000V DC, fit into tight installation spaces and have excellent vibration resistance. It would also need to be high quality and easy to install.
The PerforMore connector met all the requirements of the NS bus. A two-stage locking mechanism enables quick and user-friendly operation as well as high occupational safety. The easy handling saves a lot of time during assembly and maintenance, where safe and reliable operation is essential in high-voltage applications.
Aside from city buses, other closed-loop vehicles include trucks and equipment at ports as well as construction and mining equipment. In 2006, the California Air Resource Board (CARB) performed a study on air pollution emissions sources at California harbors, and created a plan to reduce emissions of pollutants such as diesel particulate matter, nitrogen oxides, sulfur oxides and reactive organic gases. CARB’s plan included a goal of 95 percent reduction in diesel PM and 70 percent reduction in NOx by 2010, which could be achieved by switching diesel engines in trucks and equipment to diesel-electric hybrids.
Because these port vehicles move within a specific area, electrification is a good solution for this application. Charging infrastructure doesn’t need to be provided across a city, state or country, only at a central location. Because the extreme traffic of diesel-powered vehicles in this concentrated location causes pollution problems, the clean and noiseless operation of electric vehicles provides real benefits.
While air quality is an environmental and quality-of-life concern for municipal governments, for the mining industry it is a cost concern. According to Kim Trapani, a Stantec ventilation and energy engineer, ventilation contributes to about 30 to 40 percent of the total energy operating costs in underground mines, and a switch from diesel to electric vehicles can reduce that cost by 35 to 50 percent.
E-mobility is accelerating due to consumer environmental consciousness and incentive programs, but most importantly because it is evolving into the lowest cost transport method in many sectors. Stäubli’s PerforMore connectors offer engineers high-performance, certified solutions to an industry which handles more power, with less weight, faster and at lower cost with every new design.
To learn more about Stäubli’s PerforMore connectors, visit the website.