Ultra-Small Temperature Sensor for Batteries

In terms of the safety of energy storage batteries and power batteries, temperature acquisition and control are crucial. A temperature sensor with excellent consistency can effectively monitor battery temperature changes and prevent thermal runaway in advance, causing serious attenuation of lithium battery energy and power. This ensures the safety of energy storage batteries, power batteries and the stability of new energy.

The “uncrowned king” in the field of temperature sensors for energy storage batteries and power batteries has reported another technical success. Invented a temperature sensor that uses ultra-small multi-point temperature measurement inside the battery, the first in the world!

Traditional thermistors have a one-step silver-burning electrical polarization process. The performance of the overall product is affected by the matching of the silver paste and thermistor body material. Especially for SMD and plug-in NTC, the welding is all soldering. This process leads to defects such as desoldering, silver eating, and porcelain explosion. At the same time, due to the difference in temperature resistance of the welding material, the difference in thermal expansion coefficient, and the difference in chemical bonds between the glass phase and the porcelain body. As well as the influence of external production process hygiene and other conditions, the overall temperature resistance level of the thermistor is not high. Moreover, this electrodeization + lead wire welding process limits the size of the thermistor. The smallest size available is Japan’s Shibaura diameter of 0.45mm.

YAXUN, which has provided external temperature measurement services for hundreds of energy storage and power batteries, has already realized in 2022 that “the problem of internal battery temperature measurement is still a difficult problem for the industry!”

According to feedback from many battery technicians, the current temperature of batteries is measured by transmitting the internal temperature of the battery through the battery poles.

Once the heat transfer speed is slow and the true temperature of the battery core cannot be quickly fed back, the battery will burn out and the temperature has not yet been fed back. Second, the specific location cannot be measured, so it is blind. If the temperature rise point happens to be at the farthest point of the pole, thermal runaway may occur. Third, it is impossible to measure regionally and the entire battery core cannot be measured. 4. Corrosion resistance is not enough. Traditional sensors require copper wires to draw signals, require insulation, and require anti-corrosion protection.

In order to measure the internal temperature of the battery, the temperature sensor must be ultra-small, must have multiple points, and must meet multiple other conditions simultaneously!

In 2023, after nearly a year and more than 3,000 iterations of research and development and testing, in September of the golden autumn, finally, China’s first ultra-small multi-point temperature sensor for internal battery measurement was invented!

We invented this ultra-small multi-point temperature sensor used inside the battery, which is the first in China. 1. There is no need for electric polarization treatment, and the lead wire directly forms ohmic contact with the porcelain body.
2. The minimum diameter can be 0.2mm, or even smaller.
3. The temperature resistance can reach -100~+500 degrees, and the response speed is 50 milliseconds.
Fourth, “ladder structure” can also be realized. All NTCs are hung on two conductors in parallel or series. Due to their small size, they can be coated into tapes or sheets. Realize regional temperature measurement. Any temperature rise anywhere in the area can be reflected on the sensor.

It is reported that this technology has five obvious advantages: it can perform point measurement, line measurement, and surface measurement, and realize multi-dimensional spatial measurement. The sensor body is extremely small and the thermal hysteresis is small. The sensor is in a membrane shape to maximize its proximity to the ion membrane and is fast. The metal lead-out wire is platinum wire, which has good corrosion resistance. The membrane material is also corrosion-resistant (polyimide or PE, PP, etc.), temperature-resistant, corrosion-resistant, and tensile-resistant.

“This set of technology-related process methods and slurry formulas have applied for relevant patents.”