Semco university – All about the Lithium-Ion Batteries


BMS: The Brain Behind Your Battery’s Brawn

The purpose of the BMS Battery Management System also referred to as the battery nanny or housekeeper, is to intelligently manage and maintain each battery unit in order to prevent overcharging and over-discharging, increase the battery’s service life, and keep an eye on its condition.

The BMS battery management system unit consists of the battery pack for powering electrical equipment, the control module, the display module, the wireless communication module, the electrical equipment, and the battery collection module for gathering battery data for the battery pack. Wireless communication is facilitated by the communication interface of the BMS battery management system. The display module and the module are linked.

The BMS battery management system’s input end is linked to the acquisition module’s output end. The input end of the control module is connected to the output end of the BMS battery management system. The electrical equipment and battery pack are connected to the control module, respectively. The wireless communication module is used to connect to the BMS battery management system. The server is linked to the block.

BMS function

The electric vehicle’s power battery and battery management system are closely related. Through sensors, it measures the battery’s voltage, current, and temperature in real-time. It also computes the remaining capacity (SOC), discharge power, leakage detection, thermal management, battery balance management, and alarm reminder, and reports the residual capacity and degree of battery deterioration (SOH).

(SOC) state, as well as using algorithms to control the charger for the best current charging through the CAN bus interface and the onboard master controller, motor controller, energy control system, on-board display system, etc. for real-time data. Additionally, algorithms to control the maximum output power in accordance with the voltage, current, and temperature of the battery to obtain the maximum driving mileage.

The BMS is primarily made up of the following: intelligent robots, IOT smart homes, electric tools, electric bicycles, electric forklifts, BMU master controller, CSC slave controller, CSU equalization module, HVU high voltage controller, BTU battery status indicator unit, and GPS communication module. It also includes light hybrid from small to master-slave architecture. Power vehicles to electric ships, plug-in hybrids, pure electric cars, etc., and finally to the three-layer structure’s energy storage system.

Application of BMS in power vehicles

The management of nickel-hydrogen batteries on Toyota HEV models is where the concept of battery management systems (BMS) in electric vehicles originated. The BMS of NiMH batteries typically does not need to have a balancing function, control contactors, or gather the voltage of each battery (6 batteries in series) Voltage monitoring for the entire battery.

This is in contrast to lithium battery management, which is characterized by high consistency, good safety, and low monomer voltage (1.0~1.7V). The hardware of the NiMH battery BMS is relatively simple, but estimating SOC and controlling and adjusting the charge and discharge range to prevent rapid attenuation of the battery are challenging due to the intricate relationship between the memory effect and external voltage characteristics of nickel-hydrogen batteries and SOC.

The power battery system now has a higher energy density, greater capacity, and longer running time thanks to the application of lithium battery technology, which also raises new requirements for the BMS’s functionality. Based on varying project requirements, BMS is classified into two categories based on topology: Centralized and Distributed.

Core functions of BMS

1) Cell Monitoring

  • Monomer battery voltage acquisition
  • Single battery temperature acquisition
  • Battery pack current detection

Precise temperature measurement, both for a single battery and for the heat-dissipating liquid inside the battery pack, is crucial to the battery pack’s operational condition. To establish a good working relationship with the BMS, control module necessitates setting the position, number, and uses of temperature sensors in a reasonable manner. The fluid temperature at the battery pack’s inlet and outlet is the main focus of the heat dissipation liquid temperature monitoring, which has an accuracy comparable to that of a single battery.

2) SOC (charge state) technology: what is the remaining battery capacity?

Since SOC is the foundation for all other parameters in BMS, its accuracy and robustness—also referred to as error correction ability—are crucial. No matter how many protection features are included, a BMS cannot function correctly without an accurate SOC because, even with protection, the battery’s lifespan will not be increased. For batteries of the same capacity, the range of electric vehicles increases with increasing SOC estimation accuracy. The battery pack’s efficiency can be maximized with high-precision SOC estimation.

3) Equilibrium technology

In order to accomplish the goal of equilibrium, resistance de-heating is typically used in passive equalization to release the “excellable power” of high-capacity batteries. The battery efficiency is low despite the circuit’s low cost and dependability.

A high-capacity cell receives excess power during actively balanced charging, and a low-capacity cell receives excess power during charging. This arrangement can increase use efficiency, but it comes at a higher cost, with a more complicated circuit, and with lower reliability. In the future, as cell consistency improves, passive equilibrium might not be as necessary.

In conclusion, the BMS battery management system is the silent guardian of your battery’s health and performance. It’s like a battery nanny, meticulously monitoring voltage, current, temperature, and even leakage, all to ensure your battery lives a long and happy life.

From preventing overcharge and over-discharge to optimizing charging and balancing individual cells, the BMS works tirelessly behind the scenes to keep your battery pack running smoothly and safely. So next time you plug in your electric vehicle or power up your favorite gadget, remember the unsung hero – the BMS battery management system.


About Semco – Semco University is an educational website that is catering to the needs of students and researchers. Offering information on Lithium-ion batteries. The resources and content are compiled from various sources including manufacturers, test labs, crowdsourcing, etc. Our motto is to provide a viable resource for companies, students, and enthusiasts interested in participating in the Li-ion Battery industry. Our initiative is to make people aware of the benefits, and opportunities of the revolutionary Lithium Batteries for multiple applications.

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