Paragraf Introduces Graphene-Based Battery Sensor for Battery MappingMarch 29, 2021 by Gary Elinoff
Based on the Hall Effect, the new device is well suited for evaluating electric vehicle battery cell chemistries
The GHS01AT Hall Effect sensor offers measurements similar to that of more complex magnetic sensors. With the small size and ease of use of characteristics of Hall sensors, it can provide a more precise picture of localized, point-to-point battery cell behavior.
The GHS01AT. Image courtesy of Paragraf
What is the Hall Effect?
The Hall Effect is noticed when an electric current flows through a conductor and there is a magnetic field perpendicular to the conductor.
The Hall Effect. Image courtesy of the Optical Society
As illustrated above, the positive and negative charge carriers will migrate towards the edges, producing a voltage differential measurable between the sides. The effect is especially pronounced in a thin, flat conductor, and the graphene-based device sports a graphene monolayer that’s a mere 0.34 nanometers thick
Because the GHS01AT is animated by the Hall effect, it can react to the magnetic field induced by the internal current flowing through a battery cell.
Multiple GHS01ATs Map Battery Cells in Real-Time
By measuring the magnetic field induced by current flowing through the cell, users will gain knowledge of those current flows. With the GHS01AT mapping out current densities, knowledge of actual local cell internal resistances in real time is gained.
Groups of GHS01ATs can be used to map out the current flows through an entire battery cell in real-time. And it can do so during multiple charge/discharge cycles. It can also focus on different areas within a cell.
In research settings, knowledge of internal current flows and hot spots can be invaluable for investigations into battery chemistry. In quality control, defects can be ferreted out easily. For maintenance operations, signs of battery cell aging can be detected.
The Need for Better Data
Batteries are thought by many to be the crucial factor holding back EV adaptation, and manufacturers are under pressure to improve their products. Dr Simon Thomas, CEO of Paragraf, believes that “to do this, they must have access to superior test data that they can analyse.” and “Thanks to our GHS01AT, they now have the technology necessary for such an analysis.”
“This new device easily outperforms what is currently available in terms of both magnetic field and spatial resolution. It means that, for the first time, battery manufacturers can compile comprehensive datasets relating to the internal structure of their products from a current density perspective,” he goes on to say that “By implementing test rigs incorporating GHS01AT sensors, they will be able to ensure the long-term operation and safety of the battery packs they produce.”
GHS Array Starter Kit
The GHS Array starter kit allows up to eight of the devices to be used at a time.
In the image above, one of eight GHS01ATs is shown on the left, connected to the main PCB. It, in turn, is connected to the designer’s data acquisition system and power supply.
The next image shows how this array can be used to study an actual battery cell.
GHS Array starter kit applied to battery study. Image courtesy of GHS Video (1:00)
Here, eight spots are simultaneously monitored, over time, for internal resistance, aging and hot spots
Application for the GHS01AT and the Starter Kit
Aside for battery applications, the pair will also find use in:
- Magnetic materials research
- Magnetic sorting
- Electromagnet mapping
- Electric motors and bearings. Check for defects and their causes