Battery technology has advanced significantly over the years, and people have learned about different battery management systems. In this article, the main focus will be on the battery management system’s architecture and the functional blocks.
The electrical devices present at the moment are highly mobile. The advancements in battery technology have fueled the progression of different products such as portable power tools and wireless speakers.
The Building Blocks of the Battery Management System
This is a system that comprises the following blocks: a fuel gauge monitor, cutoff FETs, cell voltage balance, cell voltage monitor, temperature monitors, real-time clock (RTC), and state machines. There are different ICs (Integrated Circuits) that are being used to handle battery management.
The functional blocks have been grouped in a manner that showcases monitoring and balancing, and a micro-controller should be put in place. Using such an integrated solution, the system usually runs autonomously.
FET Driver and Cutoff FETs
This is a functional block that usually isolates and connects the battery pack between the charger and load. The drivers have been designed such that they can be connected to the low-side or high-side of the battery pack. For a high-side connection, you need a charge pump driver that will then ensure the NMOS FETs have been activated. For a low-side connection, there is no need for high voltage devices, which also consume a lot of space.
Current Measurements/Fuel Gauges
This is a block that monitors the charge that exits and enters the battery pack. The fuel gauge can be designed using different techniques.
For the block used to measure current, analog comparators are used for over-current and short circuit conditions.
Maximization of Battery Lifetime and Cell Voltage
To determine the overall health of the battery, the cell voltage should be measured regularly. When the battery is operated at a specific voltage range, its lifetime goes down. The cells are usually connected in parallel or series to come up with a battery pack.
The current drive goes up when there is a parallel connection. For the series connection, the overall voltage will go up.
It also is important to use single point watering systems to extend the lifetime.
When there is a hot plug event, the balancing circuitry usually receives harsh treatment. An OFF button has also not been put in place. When the battery is connected to a load, a large transient can occur at the input. A designer should keep in mind that sensitive pins with a maximum rating are preferable since they can help determine whether a transient event will occur.
The manufacturer of the integrated circuits makes sure the ICs with a high voltage capacity won’t fail because of a transient event. The design, in this case, will be altered, and the costs will go up. For the low voltage process ICs that cannot exceed the process rating, components such as resistors, capacitors, and diodes come in handy since they dampen the transients.
A high voltage IC also comes in handy as it offers protection from extraneous and harmful signals. The only issue is that the design should be altered during the development state to ensure the device will not be affected by harmful events.
Currently, batteries usually produce a constant voltage, leading to the battery catching fire. The chemicals also present in the battery are volatile, and they can catch fire. With temperature monitoring, you can assess the safety of the battery. Temperature sensors monitor the entire energy storage system.
Battery management systems usually make use of functional locks and certain design techniques. The requirements should be considered carefully. Battery life goals will also offer some guidance on the matter. Everything, in this case, should optimize battery life.