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Accuracy of Current Sense Measurements
using Bourns
®
CSM2F Series of Shunt
Resistors in High Energy Storage Applications
By Bourns, Inc.
Introduction
Battery Management Systems in High Energy Applications
such as HEVs and BEVs need to monitor the state of health of
the Lithium-ion cells in their battery packs to maintain safety
and performance during charging and discharging. One very
important reason for this monitoring is safety, as Lithium-ion
chemistries are prone to degradation and aging or even
thermal runaway if either the ambient temperatures are out
of specification, or if the batteries are undercharged or over-
charged leading to cracking of carbon and lithium plating.
The three parameters used to determine the state of health of
a cell are cell voltage, temperature, and current, which need
to be measured by the Battery Management System. While
Shunt Resistors are passive components with a relatively high
absolute tolerance of 5 percent, the overall accuracy when
combined with a current sense module can be as low as 0.01
percent. This application note provides some information on
accuracy obtained using a Bourns
®
Shunt (CSM2F series) and
a current sense module designed for this purpose.
Figure 1: Block Diagram of Battery Management System
Table 1
