NXP 2021 21
MC33772 LI-ION
BATTERY CELL
CONTROLLER
LEARN MORE u
Ensure safety
A BMS contributes to the safety system by protecting the
battery cells. The BMS continuously monitors critical parameters
between specific safe limits to ensure the system is working
as expected. In the case of an event on which the defined
conditions are not met, the system considers this a hazard
risk and steps in to protect the batteries–as they are highly
sensitive. The key elements constituting a BMS monitor are a
battery over-voltage, battery under-voltage, thermal runaway,
and battery under-temperature.
Deliver performance
One of the BMS challenges is to obtain the best performance
from each one of the batteries. BMS mainly focuses on
accomplishing three goals: utilizing the power stored in the
battery the best way possible, accurately reporting the state of
the charge, and safely charging the vehicle as fast as possible.
To report the state of the charge precisely, it estimates the
batteries' current charge and calculates how many more miles
the driver can cover with the remaining charge. Providing
this information helps to reassure EV drivers who might be
concerned about running out of battery in the middle of
nowhere. It monitors the health of the batteries as they degrade
over time.
Increase battery life
Ensuring the battery cell balance helps keep batteries healthy
for longer and ensures there is no over- or under-voltage
when the batteries are charged or discharged. Batteries are
composed of several hundred cells in a pile together, providing
the voltage. Ideally, each cell should produce the same voltage
level. In reality, each cell might have a small mismatch when
manufactured or can degrade differently over time–leading to
different levels and faster discharge times.
The development of any battery management system involves
thoughtful hardware and software design. NXP offers a reliable
portfolio of dedicated BMS devices, providing carmakers both
hardware and software reuse for different vehicle electrification
architecture options. These options aim to provide safety and
performance while achieving a long battery life. NXP products
targeting various automotive and industrial applications
include:
• FS6500 safety power system basis chip (SBC) with CAN
flexible data transceiver
• 6-Channel MC33771C Li-ion battery cell controller
integrated circuit (IC)
• 32-bit Power Architecture® based MPC5775B/E MCU
engineered for BMS and inverter applications
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Figure 1: The main functions of the battery management systems (BMS)
are to ensure safety in the design, deliver the best possible performance,
and increase battery life
The majority of carmaker
fleets offer progressively
electrified vehicle
options that cover both
customer and government
requirements.
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