E-Mobility Engineering 017 l ECE Doosan electric excavators dossier l In Conversation: Matt Faulks l Battery testing focus l Battery Show North America 2022 report l Ariel Hipercar digest l Cathode materials insight l Thermal management focus

“We thought a lot about all those sources of error, and designed our components in a way that minimises them,” he said. “We also highlighted those points in our recommendations for how the system should be used.” Stephen Glazier chose measurements of coulombic efficiency – the discharge capacity divided by the charge capacity of a cell – to explain the difference between accuracy and precision in this context, and its importance. He showed a plot of eight cells being measured by other cyclers including Novonix’s new 10 A module. “Some of those cyclers have good precision, cycle-to-cycle measurement being pretty consistent, but poor accuracy between cells when making the exact same measurements,” he said, contrasting that with the much more consistent performance of Novonix’s UHPC system. “Its performance is identical in coulombic efficiency measured to the fourth decimal place, but on the other cyclers if you had a slight difference between two cells you wouldn’t be able to distinguish it from the noise.” He also emphasised two other important metrics on which UHPC produces accurate data. The first is capacity fade, or how much capacity is lost during every cycle, a figure that is used to estimate cell lifetime in terms of cycles to 80% of original capacity. The other is charge endpoint capacity slippage, which is hard to measure accurately but provides information on how much excess charge from reactions other than those that lead to capacity fade are happening in the cell. The reactions generate current, and can indicate the presence of hidden mechanisms that can lead to sudden cell failure, such as oxidation of electrolyte at the cathode, which leads to electrolyte loss and dissolution of transition metals from the cathode. “Some of these things lead to the rollover failure that you can’t really predict when you just look at the capacity fade plot over a few hundred cycles, as capacity then drops off suddenly,” he said. “With UHPC you can start to see these trends.” The 10 A UHPC channel module is designed to complement and integrate with the existing 20 and 2 A modules, offering eight independent channels each with six high-precision current ranges (100 µA, 1 mA, 10 mA, 100 mA, 1 A and 10 A). Parkinson said Novonix re- engineered the hardware and circuitry to provide a more robust platform for future growth in capability. “We used a single reference chip to tie all eight channels together,” he said. “This architecture means we can get tighter calibration from channel to channel, and if there is any drift on an individual channel, it can be quickly detected.” Glazier described the 10 A module as a multi-purpose device that offers a lot of flexibility in a 4U enclosure. “Imagine taking a big, 50 Ah cell and running a charge/discharge protocol that involves a C5 charge and a C500,000 charge on one device, all automatically, all while measuring current with a precision of better than 20 ppm.” In terms of software, the focus is on ease of use and intuitiveness, so that scientists and engineers using the equipment don’t have to think much about setting the equipment up, but can concentrate on their data. Glazier added that the new hardware development opens up the opportunity for more flexibility in operation, and that the company is exploring future software releases that could unlock more capabilities and features for UHPC systems. Burster showcased its new model 2511 measuring module designed for fast and complete checking of cells and modules in automated battery production facilities, including gigafactories, as a replacement for measuring systems originally designed for laboratory use. Adam Giorgione said such systems are large and lavishly equipped in terms of functions, but tend to have partially outdated comms and control interfaces. Giorgione described the 2511 as an innovative, fast and extremely compact measuring module that can be networked using several Fieldbus comms standards. Burster’s model 2511 is designed for fast checking of battery cells and modules in high- volume automated assembly plants January/February 2023 | E-Mobility Engineering 45 ShowReport | Battery Show North America 2022