ISSUE 012 Winter 2021 Sigma Powertrain EMAX transmission dossier l In conversation: David Hudson l 48 V systems focus l 2021 Battery Show North America and Cenex-LCV reports l Everrati Porsche 911 digest l Switching insight l Motor laminations focus

Cell engineering A s well as serving as a forum for discussing EV technologies, the demands they place on batteries and industry’s adaptive responses, the Battery Show North America also provides a showcase for new kit designed to make the EV engineer’s life easier. This year’s event, which took place in Novi, Michigan, was no exception, with industry presenting precision measuring instruments, test equipment, battery management systems and more. With burgeoning awareness of issues around sustainability, ethics, waste and whole-life emissions, the ability to track battery materials and components throughout their global supply chains is increasingly important. This was the thrust of a presentation by enterprise software specialist Circulor, which is working with partners to develop a digital battery passport that stores data throughout a battery’s life cycle. Veera Johnson said, “The key to using data for resource security is to track physical commodities themselves rather than tracking the paperwork as a proxy for them, to create an immutable record of the chain of custody of the material. “The process begins with the creation of a digital twin of the physical object that contains the details from a secure tag attached to the object as well as other data such as location, process undertaken, emissions and so on. This digital token can be likened to a Bitcoin, with the record of all transfers of that token secured by a blockchain as well as what has happened to the raw material or item it as it passes through various manufacturing processes. The battery passport is an example of this kind of document.” That makes it possible to trace the material through refining, shipping, manufacturing, logistics and final assembly using IoT technologies including GPS, QR and NFC tags, mass-balance techniques, RFID tags and product ID devices. “It also means end-products can be traced back to their sources and through reuse and recycling processes, enabling organisations to make informed decisions about their efforts to reduce their carbon footprint,” Johnson said. She also emphasised that Circulor uses machine learning and business logic to detect potentially suspicious anomalies. Carlton Brown at Dukosi explained how the company plans to revolutionise battery management systems by replacing most sensing infrastructure with on-cell monitoring and processing connected wirelessly to the BMS. This approach eliminates the comms bus in a conventional BMS, eliminating electrical connectors for comms and 400 V comms isolation circuits. Also gone are the 60 V PCB assemblies that have 12- to 16-cell analogue front- end (AFE) chips, which limit scalability and pack architectures, and the need to prevent 60 V surface tracking. As the sense lead wire harness bundles and the module sense lead frame are designed out, there is no risk of short- circuits between them, and no need for hundreds of connector pins. The new idea, which Dukosi called the intrinsically isolated cell-level BMS, achieves its isolation by connecting a BMS integrated circuit to each cell separately and by wireless comms from each cell-level BMS IC with the main controller via a bus antenna. Each IC has an AFE connected to sensors, an integrated microcontroller for data storage and processing, and a radio- frequency NFC transceiver and antenna that communicates via the bus antenna to the Dukosi radio manager in the main controller, which also houses the main BMS processor. In this architecture, intelligent cells monitor, process and communicate, providing the main controller with voltage, temperature, current, SoC and SoH, plus fault codes and histograms for each cell. Peter Donaldson reports on some of the new battery- related products unveiled at this exhibition 42 Winter 2021 | E-Mobility Engineering Polestar uses Circulor’s blockchain traceability solution at scale to keep track of the cobalt used in the pouch cell batteries in the Polestar 2