EV batteries get a precision boost with diamond quantum sensor breakthrough

A team of researchers is exploring the potential of using diamond quantum sensors to improve the way we monitor electric vehicle (EV) systems.

They have developed a prototype EV battery monitor with a diamond quantum sensor that has both high sensitivity and a wide dynamic range.

The researchers aim to address the technical challenges related to how diamond sensors, specifically their Nitrogen-vacancy(NV)-axis, align with external magnetic fields.

“Diamond sensors can intrinsically operate from cryogenic temperatures to temperatures as high as 600 K,” highlighted the researchers in an article published in the journal Frontiers in Quantum Science and Technology.

“However, implementation precautions are required to exploit the inherent performance of diamond quantum sensors.”

Overcoming alignment challenges

The study found that even small misalignments in the sensor could result in significant errors in the sensor’s resonance frequency.

The researchers developed a method to measure and adjust for these misalignments, greatly improving how accurately the sensors respond to currents ranging from 20 to 1,000 amperes (A).

“We studied key implementation points necessary to achieve the ideal accuracy when applying diamond quantum sensors to EV battery monitors,” remarked researchers.

Diamond quantum sensors are particularly interesting because they use NV centers, which are tiny defects in diamonds, as the basis for measurement.

These sensors are quite sensitive to magnetic fields and can work at room temperature. This makes them ideal for real-time applications like monitoring the condition and performance of EV batteries .

Experimental setup

In their study, the researchers systematically examined how misalignment affects sensor performance.

They used a specially designed diamond crystal, known as a high-pressure high-temperature (HPHT) type Ib diamond, which contained a specific number of NV centers.

The sensor was tested under different magnetic fields while also keeping track of the temperature of the busbar—an essential part of EV battery systems.

“Specifically, the normal operation from −150°C to 150°C of the EV battery monitor was verified, suggesting that the prototype EV battery monitor may be applicable not only on the ground but also in space and in deep seas with hydrothermal deposits,” highlighted the article.

The experiments produced data that were then analyzed using a least-squares fitting method, a mathematical technique to find the best-fitting curve for the data.

Outcome analysis

This analysis helped the researchers determine coefficients that describe how changes in the busbar current influence the sensor’s resonance frequency. These findings allowed them to make adjustments that improved the sensor’s accuracy.

“Now, a method for quantifying the misalignment between the NV-axis of the diamond sensor and the static and current magnetic fields has been developed, and the misalignment can be minimized,” concluded the research team.

It demonstrated that with precise alignment and adjustments, diamond quantum sensors can measure magnetic fields with high accuracy, which is essential for the safe and effective performance of EV batteries.

Furthermore, this research might also benefit other quantum sensing technologies, improving their accuracy and reliability.

As the need for precise monitoring in sustainable energy systems increases, the findings from this research could lead to significant technological advancements.