Battery digital twin standard to drive EV sustainability

Battery performance, supply chain challenges and their carbon footprint are some of the biggest bottlenecks for the electrical vehicle (EV) industry. A new Battery State of Health (SOH) Standard will make it easier to create digital twins of different battery designs and the processes that produce them to address all these challenges. 

The standard supports tools to ensure EV batteries are produced, distributed, maintained and recycled safely and sustainably. This promises to open the door to an array of second and third-life battery uses, such as creating decentralized energy storage systems. It will also allow EV owners to check whether a battery needs to be recharged or replaced and help used car buyers estimate future replacement costs. 

The new standard is a foundational component of the Mobility Open Blockchain Initiative (MOBI) launched in 2018. MOBI’s founding members include Accenture, Aioi Nissay Dowa Insurance Services USA, BMW, Bosch, Ford, General Motors, Hyperledger, IBM, IOTA Foundation, Groupe Renault, ConsenSys, ZF Friedrichshafen AG and many more. It has since grown to over one hundred members. 

Before MOBI’s launch, many mobility and tech communities were experimenting with blockchains and building proofs-of-concept to demonstrate the technology. MOBI cofounder and director Tram Vo told VentureBeat, “These companies found that putting a vehicle, data, or service on a chain was easy, but scaling was hard,” MOBI cofounder and director Tram Vo told VentureBeat. “Without common, agreed-upon standards of identifying things, sharing data and transacting within a business network, the technology itself had little use for global enterprise applications.”

Measuring health

The definition of battery SOH is calculated as a ratio of total maximum capacity at any given time compared to the beginning of life capacity (or rated capacity). Vo said that when the ratio dips below 80%, the battery has reached its end of life and needs to be replaced. The original pack is often repurposed for a second life. These batteries consist of cells, modules and a pack and so the definition of SOH carries for individual components in the pack. 

Battery SOH can also be calculated using impedance (or resistance) and represents the thermal limit of the battery. When the SOH is measured using capacity, it is also called “capacity fade” as maximum capacity decreases over time.

Vo said the ability to measure and track battery SOH would enable EV owners to recharge/recycle batteries in a timely manner and help eliminate range anxiety. This promises to drive more potential buyers to purchase new and used EVs. 

SOH tracking will also open an array of second and third-life uses for batteries and unlock the potential for more seamless decentralized energy storage systems by fostering greater visibility within the battery lifecycle. SOH tracking will also give stakeholders valuable insights into how batteries are affected by various factors and may help manufacturers design more durable batteries. 

“SOH tracking will allow us to extend the battery life cycle, expand primary and secondary EV markets and harness unused energy to power the grid, enabling a more circular distribution of renewable energy around the globe and streamlining the battery recycling process,” Vo said. 

Vetting battery data

The new standard will utilize a decentralized data network for authenticating battery data across stakeholders. The battery identity number (BIN) standard specifies the format, content and physical requirements for a globally unique identity of battery packs. Vo said it is like a vehicle identification number (VIN) for vehicles. 

It provides an indelible BIN on battery packs to facilitate 1) battery identification information retrieval; 2) accurate and efficient battery recall campaigns; 3) a global battery passport; 4) traceability across the battery component supply chain; 5) recycling certification; 6) battery swapping and 7) life cycle traceability.

The BIN is composed of a battery manufacturer identifier (BMI), a battery descriptor section (BDS) and a battery information section (BIS), each of which denotes a battery’s specific characteristics, imbuing it with a unique and traceable identity. 

The group is also working on a battery Self-Sovereign Digital Twin™ (SSDT). It provides a virtual representation of a battery and its associated data anchored in a decentralized trust network using W3C’s Decentralized Identifiers (DIDs) Standard. MOBI’s community plans to use the Integrated Trust Network or ITN for exchanging data. 

Vo said this would enable authenticated access to SOH and other battery data via a computer or mobile device. The Battery SSDT also stores a combination of static and real-time data to automatically log a battery’s journey through the value chain, from raw material sourcing and manufacturing to use and recycling. 

The decentralized trust network ensures this data is tamper evident. The controller of the asset can also choose who to share this data with and how much to share. This way, stakeholders throughout the value chain can communicate across organizational lines in a privacy-preserving, secure and trusted manner. Users benefit from access to a richer account of a product’s history while protecting their privacy. 

The supply of any commodity is complex and crosses many geographical boundaries, companies, raw materials and parts. This distributed digital twin approach could help to improve transparency and collaboration between stakeholders. 

“We believe a clever combination of legacy systems anchoring data to be shared with stakeholders on a federated system along with decentralized identities will allow the stakeholders to collaborate at a much higher level,” Vo said.