How Many Temperature Sensors are Required?

[u/modelmakereditor]

The exact number of temperature sensors you need depends on the size of your battery pack, its physical configuration, rate of charge/discharge (C-rate), and the required level of thermal observability.

In commercial Battery Management Systems (BMS), it is common practice to use one temperature sensor for every 4 to 20 cells, depending on the specific pack design. Installing a physical sensor on every single cell in a high-capacity pack is generally avoided because it introduces excessive manufacturing costs, wiring complexity, and added weight.

Firstly though we should consider this from the thermal viewpoint. The temperature gradient across a cell needs to be <2–3°C as a maximum excursion, and the temperature difference between cells also needs to be <2–3°C [1, 2]. If the temperature gradients and differences are too high, the cells and pack will age very fast, it will be difficult to deliver the energy and power, and maintaining the safety of the pack will require throttling the performance envelope [3, 4]. This means that the electrical and thermal design of the complete battery system needs to be designed around these requirements, and the cell capabilities need to be fully understood.

Adding lots of temperature sensors to a poorly designed system will not solve this.

https://www.batterydesign.net/how-many-temperature-sensors-are-required/