As a core component of digital products and electric vehicles.Lithium-ion batteries in these products typically consist of multiple cells.During use, the charging and discharge performance and battery life may be clearly reduced as the internal core temperature of the battery cell increases.
Especially for the power lithium battery in the category of vehicle use, the accurate cell temperature estimation and monitoring of the performance realization and life of the whole battery system is very critical.
Recently, the US Patent and Trademark Office granted US Patent Number 10230137 to the US Army on March 12,2019.The patent can estimate the temperature of the cell in the battery pack.
The patent provides a more accurate core temperature estimation method for battery packs that can be used for battery thermal management system operations and helps maintain safety, performance and life.
At present, the monitoring of the cell temperature is still not accurate and reliable, and even in some cases is far from the actual situation. Take the existing technology as an example, one way is to measure the surface temperature of the battery cell and use it as its core temperature.But this can be very inaccurate because the temperature between the surface and the core can differ by 30℃.
Alternatively, the temperature sensor is installed in the internal core of the cell for temperature measurement.But it would be too expensive and impractical to have such temperature sensors available for hundreds or even thousands of cells.
To solve the above technical problems, the patent estimates the battery temperature by measuring the surface and coolant temperature, and by entering the internal resistance of the mathematical formula.
In detail, the method of estimating the core temperature of the cell in the battery pack may include the following steps:
1. Receive the surface temperature of one or more cells, the current of one or more cells, the inlet temperature of the coolant supplied to the battery pack, and the rate of receiving the coolant.
2. Estimates including the internal resistance of the cell aggregation, the cell aggregate conduction resistance between the core of the cell and the convective resistance between the battery surface and the coolant.
3. Estimate the core temperature of the battery cell based on the received and estimated values of the previous steps.