Category: Automotive Product of the Year
Leveraging its proprietary graphene fabrication process technology, Paragraf has brought a game-changing current density analysis solution to market. This has the potential to revolutionise future electric vehicle (EV) battery design.
Driven by consumer expectations for the next generation of EVs to be capable of covering greater distances between recharges, and for recharging to be completed with shorter time frames, EV manufacturers will need access to batteries that have exceptional properties. Alongside this there are pressures to lower the overall expense of the vehicles, by curbing the bill-of-materials costs. EV batteries are going to have to fit into areas with smaller dimensions and be more lightweight. At the same time they will need to offer elevated power density levels and support faster charging times. In many cases, the approach currently used for looking at the current densities in batteries is indirect – relying on temperature measurements. Direct methods, using fluxgate sensors, are equally problematic – as they lack the required field range and spatial resolution. Though Hall Effect sensors will deliver the real-time response to be effective in this application, they need to have performance parameters that are way beyond what conventional devices can provide – in terms of field resolution levels.
Recently released, the Paragraf GHS01AT is a graphene-based Hall Effect sensor that will have a pivotal role to play in the testing of new EV battery concepts. Relying on a graphene monolayer (which is just 0.34nm thick), the GHS01AT’s sensor element can be considered as truly two-dimensional (2D). Consequently, this device is not subject to interference from stray in-plane electromagnetic fields. Far greater degrees of resolution can be supported than with standard Hall Effect sensor devices. Furthermore, as the measurement methodology is an isolated one, it causes no disruption to the cells’ operation.
Through the GHS01AT sensors, it is possible for high-resolution data on fluctuations in current density to be acquired in real time. It can deal with the µT to mT magnetic field fluctuations that will occur within battery cells. Field resolution figures are 20ppm (in a 1T field). A linearity of <±0.5% (uncorrected) full scale is maintained across its measurement range.
The compactness of these sensors (with active area dimensions of just 1.3mm x 1.3mm) means that they have much greater spatial resolution than alternative methods. Data can thus be analysed at a granular level. Different points in each cell incorporated into the battery can be examined, with the ability to map out the current density topology across the whole battery.
By using this advanced magnetic sensing technology, EV manufacturers and their battery solutions providers will be able to scrutinise the validity of different battery designs – looking at what outcomes will result from any changes to the chemistry employed or to the form factor. They will be able to pinpoint early signs of hotspot formation, see what the implications are of charge/recharge cycles for the long-term health of the battery design (premature aging of cells, etc.), or what impact high operating temperatures might have. In addition, they will be able to undertake isolated current measurements at the anode and cathode tabs.
It will be possible to get a highly detailed and localised understanding of the behaviour of each battery cell, so that any potential issues arising can be identified and then addressed. The upshot of all this is that research and development activities may be executed at a much quicker pace. New battery designs could be created that will attain heightened performance, with both prolonged operational lifespan and assured safety.
The threat posed by functional failures or thermal runaway could be mitigated.
As well as being used in a development lab environment, these sensors could likewise be employed to carry out testing on EVs as they leave production lines, prior to being shipped. There is also scope for using these sensors to conduct continuous in-service monitoring of cells within vehicles out on the road. Another possible use will be to carry out checks on older EV batteries before they are repurposed for other applications.
Paragraf intends to work with customers to help them in the construction of test rigs featuring the graphene-based GHS01AT magnetic sensor devices which are fully aligned with their own specific test needs. To facilitate initial experiments before looking to build full scale test rigs, the company has also introduced the GHS Array Starter Kit. Complementing the release of the GHS01AT, this is a highly effective board solution that enables measurements to be taken from up to 8 GHS01AT devices simultaneously. A probe with a 1.5m cable is attached to each sensor. A built-in temperature sensing device accompanies each probe. This allows temperature compensation of the acquired data to be benefited from. The board is simple to integrate into existing data acquisition equipment, using a serial interface connection.
Though names cannot be disclosed at this stage, Paragraf is already carrying out in-depth trials with some of the leading world’s EV manufacturing brands.