Li-ion/polymer cells cannot be used directly
in electronic devices. They have to be assembled with a PCM (protection
circuit module) and other components of different devices. Sometimes the
more complex designs such as smart battery pack may use integrated PCM
and BMS (battery management system) which provide advanced functions such
as fuel gauge calculations, protection, cell balancing, thermal sensing,
statues indicating lights and serial communications buses.
PCM works as safety devices and it protects
cells against over charging/discharging, over current, short circuit,
over heat and etc. Li-ion/Li-po batteries must be used within the operation
ranges of 2.75V min. to 4.2V max. LiFePO4 batteries must be within 2.0V
min to 3.65V max. Otherwise they should be damaged permanently and can’t
be used again. It has following functions:
• Overcharge voltage protection.
• Over discharge voltage protection.
• Over-current protection.
• Short circuit protection.
• Battery high temperature protection.
• Battery's internal pressure increase protection.
BMS(battery management system) is a protection, control and management
system to monitor the battery status in order to protect cells from damage,
generate alarms, keep the application work normally and prolong the battery’s
service life. It is mainly used in high power lithium ion, lithium polymer
and lifepo4 battery packs. It has the major functions as follows.
• All PCM protection functions
• Measurement of voltage, current, capacity, temperature
• Charging control
• Cell monitoring and balancing
• Communication interface with application
• Power gauge
At CREUP no matter what your application requirements,
from basic PCM design to advanced smart battery management system, we
have the capabilities and engineering & design experiences to deliver.