THE COMMUNICATIONS HUB OF THE ELECTRIFIED POWERTRAIN Unpacked and unbound Inside Xerotech’s heavy-duty batteries Read all back issues and exclusive online-only content at www.emobility-engineering.com Sine language Decision support Creating the perfect sine wave for motor control Expert advice on when to use axial flux motors ISSUE 022 | NOV/DEC 2023 UK £15 USA $30 EUROPE €22
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4 Intro Advances in battery capacity, motor control and power electronics look set to make range anxiety a thing of the past 6 The Grid Scania tests a hybrid truck with built-in solar panels, ‘mini-tabs’ could help electric aircraft fly faster, Horiba MIRA opens DiL simulator, and much more... 14 In Conversation: Dr Tilo Schweers This key player in developing the smart cars range tells us what he’s learned about battery EVs 18 Dossier: Xerotech battery system Need batteries for large offroad vehicles but only a few at a time and in different sizes? This company aims to supply them 34 Focus: Motor control Efficient motor control is all about the quality of the sine wave used, and there are different techniques for getting it as close to perfect as possible, as we show 44 Report: Battery Show North America 2023 Thermal management and stopping thermal runaways were the key themes at this show, as highlighted by our round-up of the exhibits 52 Digest: Suncar ZE150W excavator ‘Next level’ electrification is the principle behind this excavator conversion. We explain what that entailed 58 Deep insight: Power electronics The latest efforts to boost the performance of IGBTs, SiC and GaN to provide better and more powerful switching solutions 64 Focus: Axial flux motors Industry experts give their views on which applications are best suited to these ‘pancake’-shaped motors 74 PS: Extinguishing lithium battery fires We report on the latest r&d into effective ways of dousing lithium-ion thermal runaways 6 52 18 3 November/December 2023 | E-Mobility Engineering Contents | November/December 2023
THE COMMUNICATIONS HUB OF THE ELECTRIFIED POWERTRAIN Unpacked and unbound Inside Xerotech’s heavy-duty batteries Read all back issues and exclusive online-only content at www.emobility-engineering.com Sine language Decision support Creating the perfect sine wave for motor control Expert advice on when to use axial flux motors ISSUE 022 | NOV/DEC 2023 UK £15 USA $30 EUROPE €22 Anti-anxiety advances Publisher Nick Ancell Editorial Director Ian Bamsey Technology Editor Nick Flaherty Production Editor Guy Richards Contributors Peter Donaldson Rory Jackson Technical Consultants Ryan Maughan Danson Joseph Dr Nabeel Shirazee Design Andrew Metcalfe Ad Sales Please direct all enquiries to Nick Ancell nick@highpowermedia.com Tel: +44 1934 713957 Subscriptions Please direct all enquiries to Frankie Robins frankie@highpowermedia.com Tel: +44 1934 713957 Publishing Director Simon Moss Marketing & PR Manager Claire Ancell General Manager Chris Perry Office Administrator Lisa Selley Volume Five | Issue Six November/December 2023 High Power Media Limited Whitfield House, Cheddar Road, Wedmore, Somerset, BS28 4EJ, England Tel: +44 1934 713957 www.highpowermedia.com ISSN 2631-4193 Printed in Great Britain ©High Power Media All rights reserved. Reproduction (in whole or in part) of any article or illustration without the written permission of the publisher is strictly prohibited. While care is taken to ensure the accuracy of information herein, the publisher can accept no liability for errors or omissions. Nor can responsibility be accepted for the content of any advertisement. SUBSCRIPTIONS Subscriptions are available from High Power Media at the address above or directly from our website www.highpowermedia.com. Overseas copies are sent via air mail. EDITORIAL OPPORTUNITIES Do you have a strong technical knowledge of one or more aspects of e-mobility systems? As we grow we are on the lookout for experts who can contribute to these pages. If that sounds an interesting challenge then don’t hesitate to explore the possibility of writing for us by emailing ian@highpowermedia.com ADVERTISING OPPORTUNITIES If you are looking to promote your company to engineers active in the electrification of vehicles, we have various advertising packages available to suit your needs. With a maximum of 25% of the publication allocated to advertising we offer a unique opportunity to become one of E-Mobility Engineering’s exclusive advertising partners, ensuring you are not lost in a crowded market. To discuss the opportunities and how we can work with you to promote your company please contact Nick Ancell nick@highpowermedia.com +44 1934 713957 THE COMMUNICATIONS HUB OF THE ELECTRIFIED POWERTRAIN SUBSCRIBE TODAY visit www.highpowermedia.com ALSO FROM HPM How important is range anxiety these days? The latest developments in battery technology, motor control and power electronics are driving up capacity and increasing efficiency to squeeze the last drop of energy out of battery packs. Machine learning techniques are being used for softswitching motor control for efficiency levels that are approaching 100%, while space-saving axial flux motors are coming of age, as detailed on page 64. The importance of range has been shown by the latest solar-powered recreation vehicle, detailed in Grid starting on page 6. The first version had a range of 100 miles, but the latest version, which uses GM’s Ultium 800 V battery pack and power architecture enhancements, boost the range to 250 miles. The latest technologies addressing the thermal challenges to boost the performance and range are detailed in our report from this year’s Battery Show North America, on page 44, alongside the latest advances in motor control (page 34) and power electronics (page 58). As ever, the debate of range anxiety lags the reality of the engineering advances across the industry. Higher density battery cells, pack design, motor control and power electronics all continue to advance the performance of e-mobility platforms, which will eventually mean the end of range anxiety. Nick Flaherty l Technology Editor EME Update Each month the E-Mobility Engineering e-newsletter provides a snapshot of the top stories on our website during the previous month. To keep up to date with the latest technological developments, sign up today at www.emobility-engineering.com/e-newsletter 4 November/December 2023 | E-Mobility Engineering Intro | November/December 2023 Read all back issues online www.ust-media.com UST 52 : OCT/NOV 2023 UK £15, USA $30, EUROPE €22 Code-makers Focus on video encoding technology The cable guys How to get the best from wiring harness suppliers Four-legged friend Keybotic’s quadruped robot for dirty and dangerous jobs in heavy industry ELECTRIC, HYBRID & INTERNAL COMBUSTION for PERFORMANCE ISSUE 149 OCTOBER/NOVEMBER 2023 When Formula One was fun Racing in the Sixties Heavy Goods Racer redefined Bizarre electric competition lorry Hemi in epic new FX attack Geoff Turk’s latest Dodge race V8 www.highpowermedia.com UK £15, US/CN $25, EUROPE e22
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6 November/December 2023 | E-Mobility Engineering The Grid Solar supplement for hybrid truck Scania has shown a prototype of an electric truck that uses solar panels to provide additional power for propulsion (writes Nick Flaherty). The truck is a regular 100 kWh Scania plug-in hybrid connected to a trailer with 200 kWh of additional batteries as a power bank. These are connected to the solar panels. “When we first began thinking about this, our starting point was the lithiumion batteries used in battery-electric trucks,” said Eric Falkgrim, a technology leader at Scania’s Research and Innovation department and the project manager for the truck. “In the time that Scania has been working with that technology, we’ve seen the batteries become lighter, cheaper and more energy-dense.” An initial 6 month pre-study in late 2019 and early 2020 showed the project was viable, and a full-scale project began in January 2021. “We specifically wanted to see if it made sense in Sweden, because if you go to places such as southern Europe, Australia or North Africa, there’s obviously a lot more sunshine,” Falkgrim said. “If it can work here in the less sunny and somewhat darker conditions then that would confirm the broader validity of the project. “The overall task seemed simple – putting solar panels on a truck and plugging it in to the electrical system. But that comes with a lot of new hardware and software systemisation and development, to make it safe to handle the transfer of power and to handle faults,” he said. There are also important safety considerations for a solar-powered truck. “You have to bear in mind that solar cells are not made to be used on a moving vehicle,” Falkgrim said. “They’re designed to sit on top of a house or wherever for 20 or 30 years. “We’ve had to address safety challenges in putting solar panels on a vehicle. It’s fairly involved from a technical point of view, but we don’t have that pressure of it being a fullscale project where we’re producing something that will be sold globally to hundreds and thousands of customers. It’s a research project that’s about seeing if the solution makes sense, and so far we believe it does.” Scania is working with Swedish courier firm Ernst Express to test the truck. “The data we already have says that solar panels contribute significantly to the energy you’re getting for the truck,” Falkgrim said. COMMERCIAL The Scania truck uses solar power for extra power
The Grid 7 E-Mobility Engineering | November/December 2023 PV system proves a good catch A start-up is working in Africa to electrify fishing boats (writes Nick Flaherty). VoltaViewAfrica was set up by a professor from the Fraunhofer research institute in Germany. Photovoltaics generate electricity that is stored in portable lithium batteries that local residents can use as individual power sources, which includes powering local fishing boats. The powerplant is based on a block-building process and consists of two 10 ft container modules with recycled photovoltaic modules and B-grade lithium battery cells from the automotive industry. It was developed by Prof Wolfgang Schade, who heads the Fibre Optic Sensor Systems department at Fraunhofer HeinrichHertz-Institut (HHI), and is technical director of VoltaViewAfrica. One module generates electricity from a 7.5 kWh photovoltaic array, while the other is used for portable water treatment. The electricity is stored in 48 V lithium-ion batteries housed in sturdy boxes and with a storage capacity of 4.8 kWh. The project developed a safety concept for the lithium batteries and sensor technology that enables fully digitised monitoring and control of the battery storage units as well as the entire powerplant. The first operational plant was formally inaugurated and handed over to residents of a fishing village called Balingho, in The Gambia, in June 2023. The fish catch will be kept in a freezer powered by the module, while the villagers gain access to clean drinking water using UV filters. “Thanks to the freezer, we can now store our catch for longer and thus generate a higher profit, tremendously improving our competitive position,” said Jawo, chairman of the Balinghobased fishermen. Upgrading the fishing boats with electric motors also reduces the total cost of ownership by more than 50% compared to the current diesel engines, and reduces local pollution. As the entire system is digitised, CO2 certificates can be used to cofinance investment costs. A Gambian company, Sub-Sahara United Vehicles, is installing a further 10 systems with a total of 50 replaceable batteries across the country over the next 12 months. SOLAR POWER Structural carbon fibre research Researchers at Chalmers University in Sweden have shown how the manufacturing of carbon fibres can be tailored for developing structural batteries (writes Nick Flaherty). They worked with Carbon Nexus at Deakin University, in Australia, to build a variety of fibres that are strong enough to use in vehicles but can also store significant amounts of energy. However, the properties of the carbon fibre vary depending on the process parameters and which precursor is being used. Some types of carbon fibre can be very stiff, but have a far too low a storage capacity, and vice versa. To be able to build efficient structural batteries, the carbon fibre needs to combine a sufficiently high electrochemical storage capacity with sufficiently good mechanical properties. The better the combined properties, the more efficient the battery. How the manufacturing parameters affect carbon fibre’s mechanical properties is well-established, but relatively little has been determined around its electrochemical storage capacity. A key step in the development of structural batteries is to understand how the manufacturing process can be tuned to optimise the multi-functional properties of the carbon fibre. The team explored the properties of carbon fibres made from the same precursor but with different tensions during processing. The research showed that fibres developed using both amorphous and crystalline phases of carbon affect the electrochemical capacity, as higher capacity is achieved by larger spacing in the fibres as well as higher void content. BATTERY MATERIALS Lithium power packs are being used to electrify fishing boats in The Gambia
The Grid Mini-spoiler alert for faster flight Researchers at the University of Bath are investigating how deploying spoiler-like devices called mini-tabs could help electric aircraft fly faster (writes Nick Flaherty). Mini-tabs can counteract the damaging vibrations caused by whirl flutter that occurs at high flight speeds. Maxon has provided the motion systems to test the effectiveness of the mini-tabs on a novel wind tunnel test rig. Whirl flutter is an instability that occurs via elastically mounted propeller rotors, causing the entire wing-rotor system to vibrate. It kicks in when a critical speed, specific to the design of a given aircraft, is reached. Beyond this speed, whirl flutter can create vibrations that are strong enough to shake the wing apart. Current tilt-rotors typically use thick wing sections to increase the rigidity of the wing-rotor system and push whirl flutter to higher critical speeds. That though comes with a cost of increased structural weight and higher aerodynamic drag, so more power is needed to lift the aircraft vertically and to overcome aerodynamic drag in horizontal mode. Active aerodynamic control devices can alter the wing loads in real time to counteract the vibrations. Such a control system would ease the need for thick wings and allow the aircraft to push past the critical speed where whirl flutter occurs. The researchers, at the Institute for Propulsion and Mobility (IPM) at the University of Bath, have designed and built a wind tunnel to simulate whirl flutter vibrations to test aerodynamic control strategies. “Testing aerodynamic control strategies for whirl flutter is not a simple process,” said Dr Sam Bull, the lead researcher at the IPM. “Not only do we have to assess their performance across a wide range of deployment speeds, we also have to observe how that performance changes on a vibrating wing – similar to what would occur on a real aircraft undergoing whirl flutter.” The mini-tab is a miniature spoiler that protrudes above and below the wing by up to 2% of the wing width – 10 mm in the experiments – to calm whirl flutter vibrations. “On an aircraft, conventional control surfaces known as a flaperon or ailerons are deployed to change the loads around the wing,” said Dr Bull. “However, the size and weight of these control surfaces mean you can’t move them very fast. Mini-tabs, on the other hand, have a relatively low mass, meaning you can deploy them much faster, giving the potential to counteract the effect of whirl flutter.” Powering the mini-tab is a Maxon EC 60 brushless 200 W motor with integrated Hall effect sensors for position feedback to support highfrequency operation with high precision and low latency. The motion system is driven with both feedforward and feedback control. The combination of the two reduces lag time and helps oppose the acceleration effects of the wing vibrations, which would otherwise cause the mini-tab to drift from the intended deployment position. “What we were most concerned about was accurate position feedback,” said Dr Bull. “We needed really clean feedback signals so we could achieve high positional accuracy at a given deployment frequency. The Maxon motion system gives us this performance. “Our experimental pressure data shows that when you start deploying a mini-tab, it changes the pressure field around the entire wing. We already know you can use these devices to augment the pressure and loads around the wing to counteract whirl flutter vibration.” No-one has experimentally tested this concept before on a moving wing, Dr Bull said. “The aerodynamic response from a mini-tab is non-linear, so it’s difficult to predict,” he added. “This adds to the challenge of designing a controller that can effectively deploy mini-tabs to counteract whirl flutter. “We’re now at the stage where we’re understanding and characterising the aerodynamics, but if we could develop a model of this in the future, we could potentially design a controller to tame whirl flutter vibrations. That would be the next stage.” ELECTRIC AIRCRAFT 8 November/December 2023 | E-Mobility Engineering A linear motor for a minitab in an eVTOL design
Battery advance extends RV range 9 E-Mobility Engineering | November/December 2023 US start-up Grounded has developed a modular electric recreation vehicle (RV) with a range of 250 miles (writes Nick Flaherty). The G2 increases the range from the 100 miles of the original version, the G1, by using a larger and more efficient battery pack. The G2 is based on the Zevo 600 platform from BrightDrop, which is backed by General Motors. The platform uses the GM Ultium pouch cells in an 800 V, 165 kWh pack. The RV has an additional 10 kWh of battery, called the house battery, to power the interior. This can be charged from the vehicle’s battery as well as 640 W rooftop solar cells. Both the vehicle battery and the house battery systems are bidirectional, allowing the vehicle battery to be charged from the house battery if necessary. Sensors in the vehicle monitor the usage of the battery systems and diagnose potential issues. The software will also learn how users operate the vehicle over time, with plans to extend the lifespan of the battery pack through over-the-air updates to provide optimisations. The Zevo is built at CAMI Assembly in Canada, and is shipped for the rest of the implementation. The G2 also includes the Starlink satellite broadband service for high-speed internet access. The G2’s interior implements a gridbased modular system with a library of modules and the ability to choose the location of each module. The modules are attached to exposed mounting rails within the vehicle, allowing customers to add and remove them. The rails can also be used by customers for mounting additional accessories. ROAD VEHICLES Detectors do more using less Nisshinbo Micro Devices has launched two voltage detectors that are designed to provide higher accuracy in ECUs and BMSs using fewer components (writes Nick Flaherty). When monitoring high voltages, it is crucial to consider the drawbacks of using traditional low-voltage detectors with an open drain output. The NV3600 and NV3601 series detectors reduce the need for additional resistors to divide the monitored voltage and pullup resistors at the output. Additional resistors can lead to an increase in component count and leakage current concerns. While the input range is 2.4 to 6.0 V, the Sense pin of the NV3600 devices have a high withstand voltage, of 42 V, with no need for a voltage divider resistor. There is also the option of NMOS open-drain or CMOS output types. These eliminate the leakage current issue and do not require additional external components. The NV3600 has adjustable hysteresis to monitor power supplies that experience large voltage fluctuations, such as those found in automotive batteries in noisy environments. The detection and release voltages can be set individually by selecting the appropriate hysteresis width based on the system requirements. This avoids false detection and misinterpretation from the hysteresis, even when the voltage fluctuation is significant. The NV3601 has under and overvoltage detection to monitor abnormalities, not only when the monitored voltage decreases but also when it increases beyond a certain threshold. It can also monitor under and overvoltage using a single chip. ELECTRONIC HARDWARE A solar-powered RV with 250-mile range A voltage detector design cuts component count
10 DiL system cuts physical testing Horiba MIRA has opened a driving simulator centre in the UK with driver-in-theloop technology (writes Nick Flaherty). The £4 million centre aims to help established car designers, start-up vehicle manufacturers and Tier 1 suppliers to develop new vehicles. The simulation technologies help developers adjust the design of multiple subjective elements of an e-mobility platform in a virtual environment rather than waiting to drive a physical prototype. At the heart of the centre is the UK’s first DiM450 dynamic motion driving simulator from VI-grade. This significantly reduces the need for physical vehicle testing and prototypes. A vehicle model developed using the simulator could avoid a maximum potential of 14,000 t of carbon dioxide equivalent, said the company. Developers can also use the smaller VI-grade Compact simulator, acquired by Horiba MIRA in 2021. Horiba MIRA uses a subjective attribute methodology with a human in the loop at the start of the virtual engineering series. Attribute development engineers can make accurate and unlimited comparisons quickly and at lower cost, often at the flick of a switch. This is especially important when working to balance conflicting attributes such as the feel of the driving and the sound of the motors to optimise the vehicle. The focus for the DiM450 is on vehicle dynamics, NVH and driveability, but also includes holistic engineering across capabilities such as advanced driver assistance systems and human machine interfaces. SIMULATION Refuelling pump seals the FC deal Researchers in the US have developed a sealed compressor using a linear motor for refuelling hydrogen EVs (writes Nick Flaherty). The hydrogen compressor, developed at the Southwest Research Institute (SwRI), can improve the efficiency and reliability of hydrogen compression used in the refuelling of fuel cell EVs (FCEVs). The linear motor drives a reciprocating compressor (LMRC) to compress the hydrogen for FCEVs and other hydrogen-powered vehicles. Unlike most hydrogen compressors though, it is hermetically sealed, and the motor increases its efficiency and reliability. “To refuel hydrogen vehicles, the gas must first be compressed to high pressures, so we set out to design a more efficient, leak-proof compressor,” said SwRI principal engineer Eugene Broerman, the project’s lead investigator. Most reciprocating compressors have motors that move repeatedly in the same motion and require lubrication for maintenance, which can contaminate the hydrogen. Instead, the LMRC’s linear motor can move the piston in a user-defined motion pattern; it is mounted for vertical motion and has a unique dynamic seal design. As a result, the compressor’s seals and bearings experience less friction, avoiding the need for traditional lubrication. A key challenge for hydrogen compression is the risk of leaks as the gas flows through equipment. “Because hydrogen molecules are so small, they sneak in and alter the performance of the materials and equipment. For instance, with the molecules causing magnets to fail, we had to coat them more effectively to prevent that.” The LMRC also uses a ceramic piston to minimise the heat expansion and lower the stress on its seal. HYDROGEN POWER November/December 2023 | E-Mobility Engineering The VI-grade Compact simulator
The Grid 11 Technical consultants Ryan Maughan is an award-winning engineer and business leader with more than 20 years’ experience in the High-Performance, Heavy-Duty and Off-Highway Automotive markets. Prominent in the development of Power Electronics, Electric Motors and Drives (PEMD) for these demanding applications, he has successfully founded, scaled and exited three businesses in the electric vehicle space. He is currently CEO of eTech49 Limited, an advisory business specialising in disruptive hardware technology in PEMD. In addition, he is Chairman of EV North, an industry group representing the booming EV industry in the north of England, a board member of the North East LEP and an adviser to a number of corporations. Danson Joseph has had a varied career in the electrical power industry, having worked in areas ranging from systems engineering of photovoltaic powerplants to developing the battery packs for Jaguar Land Rover’s I-Pace SUV. With a PhD in electrical machines from the University of Witwatersrand in South Africa, Danson has focused on developing battery systems for automotive use. After completing the I-Pace project he formed Danecca, a battery development company with a focus on prototyping and small-scale production work, as well as testing and verifying cells and packs destined for mass production. Dr Nabeel Shirazee graduated from Leicester University in 1990, where he studied electrical and electronic engineering. An MSc in magnetic engineering followed at Cardiff University, where he continued his studies, earning a PhD and developing a permanent magnetic lifting system that has been patented by the university. His interest in magnetics led to a patented magnetic levitation system that was awarded the World’s No 1 Invention prize at INPEX in the USA. In 1999, he founded Electronica, a magnetics research and design consultancy. Since then, he has been involved in various projects, including the design of an actuator motor for a British aerospace company. He has also licensed the levitation technology in France. Ryan Maughan Danson Joseph Modular plug-and-play rectifier OmniOn Power has developed a modular 30 kW rectifier in a 19 in rack format to build EV fast chargers (writes Nick Flaherty). The EV100H3NK and EV101H3N1K ACDC variants of the rectifier have efficiencies of up to 96% and integrate CAN automotive comms protocols. Up to 12 rectifiers can be used in parallel in a 19 in rack to build fast-charging 360 kW systems quickly and easily. The rectifier modules are designed with plug-and-play connectivity, allowing units to be quickly swapped out when servicing to minimise downtime. Remote firmware downloads support field upgrades. The basic rectifier design measures 13.23 in wide, 3.3 in high and 17.25 in deep for 19 in rack mounting, and uses a 480 V three-phase input. The DC output for fast-charging systems has an adjustable output range of 50- 1000 VDC that can be set by the host charger. The EV101H3N1K adds a discrete emergency power-off circuit for added safety. This enables the rectifier to comply with local or regional requirements for safety that require an electromechanical energy disconnect for rapid shutdown in case of an emergency. “Consumers want to know that a fast charger will be available and fast when they drive up to it. Using power supplies as the building blocks for nextgeneration EV chargers will help to address these issues,” said Gopal Mitra, industrial segment leader at OmniOn. FAST CHARGING Dr Nabeell Shiirazee Researchers in the US have developed a solid-state lithium-air battery cell with a potential energy density of 1000 Wh/kg (writes Nick Flaherty). The capacity is potentially four times that of the current lithium-ion battery technology used in heavy-duty vehicles such as aircraft, trains and submarines. The electrolyte is a mix of polymer and ceramic materials that takes advantage of the ceramics’ high ionic conductivity and the high stability and high interfacial connection of the polymer. The electrolyte is based on Li10GeP2S12 nanoparticles embedded in a polyethylene oxide polymer matrix. The result allows for the critical reversible reaction that enables the battery to function – lithium dioxide formation and decomposition – to occur at high rates at room temperature. It is the first demonstration of this in a lithium-air battery. “We found that solid-state electrolyte contributes around 75% of the total energy density,” said Mohammad Asadi, Assistant Professor of chemical engineering at Illinois Institute of Technology. “That tells us there is a lot of room for improvement, because we believe we can minimise that thickness without compromising performance, which would allow us to achieve a very high energy density.” Prof Asadi said he plans to work with industry partners to optimise the battery’s design and engineer it for manufacturing. The prototype cell is rechargeable for 1000 cycles with a low polarisation gap, and it can operate at high rates. BATTERIES Lithium-air’s quadruple potential March/April 2023 | E-Mobility Engineering E-Mobility Engineering | November/December 2023
EVE Tech Asia Exhibition & Conference Wednesday 22 – Friday 24 November Marina Bay Sands, Singapore www.evetechshow.com European EV Lightweight Summit Thursday 23 – Friday 24 November Frankfurt, Germany www.ecvinternational.com 4th Future Battery Forum Monday 27 – Tuesday 28 November Berlin, Germany and online www.futurebattery.eu London EV Show 2023 Tuesday 28 – Thursday 30 November London, UK www.londonevshow.com Adhesives & Bonding Expo Tuesday 5 – Thursday 7 December Stuttgart, Germany www.adhesivesandbondingexpo-europe.com Foam Expo Europe Tuesday 5 – Thursday 7 December Stuttgart, Germany www.foam-expo-europe.com Thermal Management Europe Expo Tuesday 5 – Thursday 7 December Stuttgart, Germany www.thermalmanagementexpo-europe.com CAEV Expo 2024 Thursday 14 – Friday 15 March Bengaluru, India www.caevexpo.in Vehicle & Transportation Technology Innovation Meetings Tuesday 26 – Wednesday 27 March Torino, Italy www.italy.vehiclemeetings.com Future Mobility Asia 2024 Wednesday 15 – Friday 17 May Bangkok, Thailand www.future-mobility.asia The Magnetics Show Wednesday 22 – Thursday 23 May California, USA www.magnetics-show.com busworld Wednesday 29 – Friday 31 May Istanbul, Turkey www.busworldturkey.org The Battery Show Europe Tuesday 18 – Thursday 20 June Stuttgart, Germany www.thebatteryshow.eu IEEE Transportation Electrification Conference & Expo Wednesday 19 – Friday 21 June Rosemont, USA www.itec-conf.com MOVE 2024 Wednesday 19 – Thursday 20 June London, UK www.terrapinn.com World Battery & Energy Storage Industry Expo Thursday 8 – Saturday 10 August Guangzhou, China www.en.battery-expo.com IAA Transportation 2024 Tuesday 17 – Sunday 22 September Hannover, Germany www.iaa-transportation.com The Battery Show USA Monday 7 – Thursday 10 October Michigan, USA www.thebatteryshow.com 12 Diary November/December 2023 | E-Mobility Engineering
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14 November/December 2023 | E-Mobility Engineering smart Europe’s vice-president of r&d shares some of his insights into developing the company’s distinctive battery EVs. By Rory Jackson While automotive OEMs might now agree that electric powertrains are effectively the future of all mobility, it should be remembered that only 20 years ago, many of them saw electrifying vehicles as a peculiarity at best, and a waste of resources at worst. So, by the early 2000s, very few had ventured into e-mobility. Matters weren’t helped by General Motors’ now-infamous recall of its EV1, the company citing insufficient profitability despite widespread consumer enthusiasm for the car. While most OEMs had little interest in pursuing all-electric vehicles following the GM debacle, one company went against the tide to give the world its first and then biggest success story in EVs – the smart EQ Fortwo, better known by its colloquial name, the smart. Dr Tilo Schweers not only bore witness to that car’s development, but personally led the creation of the smart electric drive programme, as the company’s head of homologation (road approval), technical documentation and special vehicle engineering for the smart’s EV and HEV programmes. That programme led to the company’s first all-electric powertrain vehicle, from the smart EQ Fortwo’s first trial through to volume production that began in 2009. Although he worked outside smart and the Mercedes family in the late 2010s, these days his career has led him back to smart, where he is now vice-president of r&d of smart Europe and leads the company’s EV design, manufacturing and certification activities in Europe and China. Surprisingly, Dr Schweers’ academic background had little focus on automotive electric power systems. “Keep in mind this was in the 1980s and ’90s, so we had different topics on our agenda back then,” he says. “But there were two main ones that influenced me back then, which I’ve carried with me ever since. One was motorbike research – for which I gave a regular lecture at RWTH Aachen University on motorbike technology and engineering – and the other was a deep involvement in the first stages of what would become electronic stability control [ESC] technology, long before it became a standard offering in passenger cars.” Particularly important to the foundations of ESC (sometimes better known as ESP or electronic stability program, as branded and popularised by Bosch) was his creation of evaluation criteria for judging the impacts of such systems in passenger cars. Notably this was a few years before recognition and standardisation of relevant criteria such as the Moose Test for evasive manoeuvring. Schweers’ research, publications, and ultimately his PhD, laid much of the crucial groundwork for ESC to become mainstream. Smart thinking The smart company and marque has returned under a German-Chinese joint venture, with r&d for its smart #1 (pictured) led by Dr Tilo Schweers (Images courtesy of smart)
E-Mobility Engineering | November/December 2023 15 Dr Tilo Schweers | In conversation To create momentum for a massproduced battery EV, Dr Schweers and his colleagues gained Mercedes’ approval to build and supply 100 cars to test with customers in London, where a congestion charge had just been enforced. “That test allowed us to build these cars from converted smart Fortwos [which were originally powered by inline three-cylinder engines], then called the smart Fortwo electric drive, and the automotive world woke up. BMW started working on the Mini Electric, for instance, and once we were satisfied with the first 100, we set our eyes on the next 2000 cars,” he notes. The second-generation electric smart Fortwo benefited from the advent of Tesla and its Gen 2 lithium-ion battery with its 16.5 kWh of energy and 18650-format cylindrical cells, as well as a growing realisation across Mercedes/ Daimler that there might be a future in all-electric mobility, enabling them to be built as original EVs rather than converted IC-engined vehicles. Three more generations of smart EVs followed, each adding energy density, range, power and other benefits from advances across the electric powertrain, particularly in permanent magnet motors and HVAC systems. Dr Schweers comments that the latter’s HV compressors for air conditioning and PTC heaters for winter might seem like little things, but were critical for making EVs comfortable and acceptable to a wider audience. “And during the fourth generation, smart decided it would only produce battery EVs going forwards, meaning smart is now the only OEM that converted 100% from IC engines to allelectric,” Dr Schweers remarks. From Bremen to Beijing Following some other projects within Mercedes, he was asked by the German car manufacturer Borgward to join as an executive director of r&d for passenger cars. “I’d grown up 500 m from where Borgward had been founded, in Bremen, so it was a name I’d regarded well since childhood,” he says. “On top of that though, and unlike my work at Mercedes, Borgward enabled me to learn about China’s companies, Making the smart In 1996, while considering moving from technical research and academia into applied engineering in the commercial world, Dr Schweers was approached by MCC (Micro Compact Car), which had recently been founded as a joint venture between Mercedes-Benz and SMH (makers of the Swatch brand of watches) to cater for drivers who wanted small, stylish city cars manufactured and personalised similarly to Swatch watches. “Right away, I started working on packaging and concept design, but after 6 months I was put into a programme to create the company’s first hybrid powertrain, intended for the firstgeneration smart car,” he recounts. ‘smart’ was chosen as the name of the marque, a combination of the Swatch name plus Mercedes and art (Swatch Mercedes art). “We didn’t know exactly which direction to go in, but it soon became obvious that humanity could not go on forever just burning fuel and not think about the consequences. So after MCC became a 100% Mercedes-owned company, and was officially rebranded as smart GmbH, we created a parallelhybrid powertrain, which at the time was one of the most fuel-economic cars with potential for homologation,” he says. “Its fuel consumption was 2.7 litres/ 100 km by NEDC test standards, 0.2 litres/100 km less than the next-best competitor, but it didn’t make it into production for economic reasons.” One of the primary takeaways from the r&d led by Dr Schweers had been that electric motors could provide great speed, efficiency and comfort in small city cars. The other was a deep insight into battery technology. “Battery EVs were less complex than HEVs, and more affordable technologically, meaning on balance a better chance of achieving business success,” he says. “In fact, the biggest challenge wasn’t an engineering one but convincing the company to let us make one.” Dr Schweers led the development and first trials of the first-gen smart EQ Fortwo in 2007, with volume production for the second gen following in 2009
16 November/December 2023 | E-Mobility Engineering culture and people, and how their fastrising automotive industry worked. What I learned still serves me hugely, given smart’s re-emergence as a joint European-Chinese venture.” In 2020, Dr Schweers returned to smart, after the company became a joint venture between Mercedes-Benz and Geely Automobile. “The primary activities of my team in Europe include automotive testing, verifying that our cars are suitable for European roads, homologation of the cars, technical compliance and so on. But it also covers a lot of other testing activities in the EU and China. The smart Automobile company With the greater maturity and range of technologies available for EV manufacturing, smart’s approach to automotive development now differs notably to that from Dr Schweers’ 20 years with smart and Mercedes respectively. “The big benefit from the MercedesBenz/Geely joint venture is that we can now design and create vehicles based on large-scale plant manufacturing,” Schweers says. “The two cars we are producing now, the smart #1 and #3, are manufactured in a factory that builds cars for various brands, allowing much greater output volumes than the old smart could manage. “Also unique for us is the MercedesBenz design. The new product generation of smart is designed by Mercedes personnel in Stuttgart, to carry on the design language of the Fortwo in a new shape and aesthetic but one consistent with the idea that these will still be economical, right-sized city cars, starting with the smart #1.” The smart #1 was unveiled in April 2022, and is an all-electric compact SUV with a 66 kWh NMC battery pack and a single, 200 kW central-drive permanent magnet AC motor running through a single-speed transmission. The pack gives the 1.8 t vehicle a range of up to 440 km (270 miles) between charges according to WLTP standards, with 150 kW fast DC charging or 22 kW AC charging. “A second, 115 kW motor can also be integrated for an all-wheel drive version of the car, and both motors are In conversation | Dr Tilo Schweers The smart #3 is the second EV unveiled by the new smart Automobile company, and is designed as a sportier version of the #1 Component packaging, driver UI and interior design in the #1 and #3 are tailored according to driver preferences
– faster charging solves it. Being able to charge your battery with the speed and convenience of refuelling a tank is the final piece of the puzzle in bringing mass-volume, mainstream battery EV manufacturing to the world. “The smart #1 charges at 150 kW DC now, but higher rates will come. Like every OEM, we’re working on improving that rate over time, but even now, if you can charge a battery from 10-80% SoC in 30 minutes, you can make an EV capable of long-distance trips. “Granted, the charging infrastructure first has to be improved in Europe and other parts of the world, but chargers and stations across most of Europe are now more than good enough for any long trips across central Europe, say. “And every new generation of batteries will shorten charging times by at least 20-30%, it’s just a matter of time before charging your battery will be like refilling your gas tank. Once the technology reaches that point, it doesn’t exactly need to improve dramatically beyond that – after all, people have to get out of their cars and stretch their legs at some point.” E-Mobility Engineering | November/December 2023 17 quite compact to help with the internal space and ergonomic packaging emblematic of our brand,” Dr Schweers notes. “Switching to hub motors might give us a bit more internal space but that’s not a technology we believe in at the moment owing to its cost and its impact on the quality of driving. “And our battery packs are pretty flat, allowing the #1 and future cars to avoid the typical battery EV problem where your foot position is too high in the car and your seating becomes uncomfortable. So it doesn’t make sense to spend a fortune making our motors, transmission or suspension 5% smaller, because customers would then have to pay for that r&d later.” The company has also unveiled the upcoming smart #3. It has been developed with the aim of being a sportier SUV, and is therefore larger than the #1 and features lower roof lines, seating positions and ground clearances, along with improved aerodynamics and range. Naturally, it is also designed for drivers seeking a more dynamic and sportscar-like look. ‘Smarter’ about batteries Moving forwards, smart’s r&d team is continuing to work on features and capabilities to tailor the new smart EVs’ differing preferences between European and Chinese drivers. Primarily this consists of modifications to the driver UI, although cabin ergonomics and similar factors can be adjusted by moving components around to suit those preferences. Any changes needed in driving and handling characteristics can be programmed through the vehicle’s electronics. “The backing of the joint venture and the software-defined nature of the EVs’ subsystems mean we can make adjustments to the car fluidly, without the expenses involved in the early and small-volume days of smart,” Dr Schweers says. “And technologically, there have been advances in batteries since then that have really made battery EVs mainstream in the automotive world, the most important I feel being ways to fast-charge batteries without shortening their lifespans. What we see now – and what was foreseeable years ago – is a change in what’s being targeted in battery r&d.” He explains that battery researchers and e-mobility strategists are moving away from attempts to pile ever more energy and range into each pack, and therefore making them and EVs unreasonably heavy. He says it makes more sense for the next generation of battery packs to come with reduced range and instead increased charging speeds. Readers may recall that this perspective is shared by Viritech’s Matt Faulks (EME 17, January/February 2023) and Nyobolt’s Dr Sai Shivareddy (EME 21, September/October 2023), whose EVs and batteries are both formulated along such lines. “If you really want to go long distances with an EV, battery size is not the enabler,” Dr Schweers comments. “Making a bigger, heavier and costlier battery is just postponing the problem Dr Tilo Schweers Dr Tilo Schweers grew up near Bremen, in Germany, and after his primary and secondary education went to the Institute of Automotive Engineering at RWTH Aachen University, where he achieved a PhD in stability control systems. After that he worked as an assistant professor at the institute from 1989 to ’94, before switching to a senior engineer role, applying his practical knowledge in several research programmes. He worked at Smart as head of homologation, technical documentation and special vehicle engineering for Smart EV and HEV programmes from 1996 until 2006, when the Smart company was absorbed into the Daimler/Mercedes-Benz group. During those years, Dr Schweers led the Smart electric drive programme and the commercialisation of the smart EQ Fortwo EV, including its volume production and meeting all the necessary safety and emissions regulations to begin selling it in North America. At Daimler/Mercedes-Benz he served as head of special vehicles, with a focus on initiating and running different EV and HEV programmes, leaving in 2016 to work for Borgward Group. In 2020, Dr Schweers returned to the reborn Smart marque as vice-president, r&d, of smart Europe, where he is overseeing the creation of smart Automobile’s next generation of EVs, including the upcoming smart #1 and #3, as well as the company’s r&d in Europe.
18 November/December 2023 | E-Mobility Engineering Unlike road EVs, off-highway vehicles need different battery solutions but in only small batches. Rory Jackson looks at how this company provides them Pick your pack For on-highway vehicles, electrification is now seen as the way to go, but the future for electrified off-highway ones such as construction dozers, mining trucks and so on is less clear. Off-highway mobile machines are often larger than the biggest on-road trucks, and vary widely in their size, power, cost, ruggedness, and weight. For example, there are 0.5 t miniexcavators and 400 t haul trucks, and if you include non-terrestrial vehicles, there are 500 t aircraft and 55,000 t container ships in need of electrification. They are also usually supplied in tens of units or even single ones, even to major industrial operators. So there’s a contrast between offhighway and on-highway automotive applications. For the latter, the problem of scarce batteries has arguably been ‘solved’, as OEMs building road EVs in batches of 100,000 or so at a time are now supplied by high-volume, low-diversity pack manufacturers. Conversely, solving the problem of off-highway packs poses the challenge of optimising a production line around low-volume, highly diverse batches, potentially just a few packs at a time. That challenge is what battery manufacturer Xerotech aims to solve. Based in Claregalway, in Ireland, it was founded by CEO Dr Barry Flannery in 2015, and the company now supplies packs to many off-highway EV OEMs. Dr Flannery began engineering battery packs in the early 2010s, and invented a new form of active thermal management, which is patented as Xerotherm. Xerotech’s batteries are built around Xerotherm, using a scalable and modular product architecture called Hibernium (a reference to Hibernia, Ireland’s name during Classical Latin times). As Dr Flannery explains, “Off-highway vehicle operators are some of the biggest companies on Earth, but even they don’t need more than a few, say, well-drilling vehicles or asphalt-grating trucks. So engineering batteries for that market means hundreds of different pack sizes, which can’t benefit from high-volume production as automotive packs do.” Within each Hibernium module, typically there are cylindrical cells and the Xerotherm system of sidewall cooling, which consists of liquidinflatable ultra-thin plastic ducts. The cells and ducts are held within a structural, insulative and fire-retardant foam. The modules come in six sizes and can be stacked up to 24 in a pack, sitting side by side and directly connected to one another by busbars. On the front of each pack sits Xerotech’s battery disconnect unit (BDU), which contains the BMS, contactors and related safety and control subsystems, along with connections from the BMS master unit to module-level slave BMS boards for lower-level monitoring and commands. But given the need for hundreds of pack sizes and the consequent length of Xerotech’s product catalogue – at the time of writing, it covered 678 different packs, each with its own eight-page data sheet – citing the exact specs for every Hibernium pack is cumbersome. To date, its largest pack is a 290 kWh solution weighing 1429 kg and measuring 2392 x 1201 x 430 mm, with a nominal voltage output of 691 V (480 V minimum, 805 V peak). Its smallest is a 10.4 kWh pack weighing
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