Battery Management System (BMS): What Is It?


Nowadays, electronic devices become more eco-friendly and more functional. Battery cells are becoming smaller and parking more power, while the old batteries are large and bulky and contain less energy.

As a result, the new generation batteries are more modest and lightweight.

A battery management system (BMS) is a system that is put in place to protect rechargeable batteries from overcharging and monitoring the charging cycle.

It collects data and provides reports on energy usage and power input

A battery pack is operated by BMS with a data bus that must be charged by a smart battery charger which makes loading easier and faster for efficiency.

Therefore, cars have become more efficient by using BMS to power these machines.

Battery Management System Architecture

A battery management system has the following parts:

  • Field effect spreaders
  • Fuel gauge reader
  • Cell voltage unit
  • Cell voltage checker
  • Real-time timer
  • Temperature checker
  • State machine

A video about Battery Management System:

Field effect spreaders

Field effect spreaders are in control of the battery assembly between the load and charger. The FETs performance is established by measuring battery-cell voltages, current frequencies and real-time circuitry.

Hence, correct connections and wiring will get the whole system working properly.

Fuel Gauge Monitor

The fuel gauge tracks currently coming in and getting out of the battery pack. Besides, the charge is the product of current and time.

The BMS measures the energy flow by using a current sensor. Then, signals will be sent to the data chip showing how much is coming in and going out and the calculates how much power is left in the cells.

Cell Voltage Monitor

Keeping track of the cells voltage of each cell within a battery pack is critical in determining its overall wellbeing. All cells are supposed to charge and discharge within set standards to make sure they are operating well.

Therefore, this makes them more durable and able to retain more charge giving more power to the user.

Operating outside the set voltage range reduces the durability of the battery which can destroy them. As a result, cells are connected in a series or parallel to form a battery pack.

A parallel connection is great for current drive, while a series connection raises the overall voltage giving more energy.

Temperature Checking

When high currents run through the batteries, it can cause fires due to the high temperatures. The contents of the cells are highly volatile.

Temp monitoring is done for safety and but also to check if the batteries are charging and discharging correctly.

Temperatures are monitored for each cell for the energy storage system (ESS). In addition, thermistors are commonly used to check each circuit heat levels. I

It’s critical to maintain the recommended levels of temperature in the cells to reduce inaccuracies in readings.

State Machines

A BMS requires a microcontroller to manage information from the circuity and make conclusions using this data. So, an algorithm is programmed into a chip to provide the solution.

This memory and real-time clock (RTC) are used in the black box.

In addition, the RTC gives timely info and the chip stores data letting the user gauge the how the system is functioning and look for problems that may arise.

 There are two ways of building BMS architecture: having multiple cells in a series and in a parallel arrangement. 

Batteries with four cells in either arrangement have balancing benefits. If a cell is weak, its bad performance is offset by the rest.

However, the non-performing cell needs replacement because it affects the whole pack which could be wasting charge.

What Does Battery Management System Do?

Protecting The Battery Pack

It protects the cells from having too much charge or discharging(cell voltage is too low) because the instabilities in the cell voltage could destroy the battery and cause deterioration of the cells.

To get the most out of your batteries, the BMS monitors the voltage coming in and out to extend the battery packs use.

Calculating How Much Charge Is in The Batteries

The BMS also calculates the amount of charge stored in the cells by tracking energy getting in and out of the pack and monitoring voltage. Moreover, the difference is the charge that is stored in the battery.

Knowing the energy levels enables the user to know who much power is available for use and take measures to recharge or reduce consumption for extended use.


Monitoring Battery Pack Health

The BMS work is to keep the pack at its optimum. This is by continually tracking the various components in the package. It checks for wire shorting, loose wiring, rotting insulations, and damaged cells

Because damaged parts have a general effect on the workings of the whole system.

Other functions Of BMS

Balancing all the cells in the unit to prevent energy wastes by diverting excess energy from the fully charged cells to ones.

This leads to stability in the system making the battery work at capacity when the fit cells support the weaker ones.

Helping track of the unit’s temperatures is very critical. Overcharged cells get hot which may cause a fire. Therefore, a battery fan controls heat in the pack ensuring it stays within set limits.

Real-time clock sends information to other devices that include:

  • Chargers
  • Motor controllers
  • Data
  • Displays

As a result, the battery management system enables the user to know the perimeters they are working with.

 The data chip stores error codes and also a comprehensive diagnostics data which is helpful when it comes to fixing matters within the battery pack if any problem occurs.

Important Notes

Battery management systems are very important for today’s gadgets which require more power to run. Because they keep track of batteries making sure they work well and charge properly to make sure you always have enough charge for use.

A BMS makes your cells last longer by continually tracking them to make sure they are loading correctly and the temp levels are healthy to make them function better.

Depending on your power needs, you will know how many cells to put into a pack to fully satisfy your power need.

Bonus: Best Battery Testers Review 2019