Issue link: https://resources.mouser.com/i/1442820
| 23 | The data at several DC currents ranging from 10mA up to 20A was recorded and the accuracy calculated as shown on the graph in Figure 5. The accuracy tends to degrade once the currents increase beyond 10A and the shunt starts to heat up. The resistance value used to calculate the current will drift as a result which worsens the accuracy of the measurements. However, Bourns can provide a look up table showing the normalized increase or decrease of the resistance with temperature. Thus, the original value used for the resistance can be modified by the factor shown in Figure 6 correlated with the temperature sensor reading. Conclusions Currents of several hundred amperes are measured by Battery Monitoring Systems in E Mobility applications during battery charging and discharging. Accurate current measurement provides critical information for safety and also for ensuring long lifecycles of battery packs. An ultra-low resistance shunt resistor together with a precision AFE can provide very accurate readings from very high to very low current levels. Temperature sensing together with look up tables from Bourns can improve the accuracy as the temperature increases. Current Sense Amplifiers with low offsets and high common mode voltages enable high accuracy with the shunt being placed at the high end in 48V applications. Bourns ® CSM2F series of shunt resistors are manufactured in an IATF approved facility and are approved for automotive applications. Figure 5: Accuracy of Bourns ® Model CSM2F-8518 Shunt with Current Sense Module Figure 6: Data from Look Up Table Showing Resistance Drift with Temperature