Electric vehicles (EVs) are the future of mobility, and each year the market is witnessing a significant rise in demand as well as production globally. This EV-centric perception of mobility has been primarily necessitated by climate change, and is now being facilitated by evolution of Li-ion batteries. These are batteries with a highly dynamic and sensitive composition. However, when managed under ambient conditions and with adequate care throughout different scenarios, the batteries can function optimally and safely. To understand the true dynamic of the relationship between a battery management system and efficiency, we need to take a deep dive into the operational aspects of management.
Common battery safety hazards
To begin with, let’s first take a look at the common battery safety hazards.
The sensitive nature of EV batteries makes them prone to various safety hazards during their lifecycle. These include manufacturing defects, electrical mishandling, thermal abuse, mechanical abuse etc. At times, the contamination of the chemical composition can cause the batteries to deplete rapidly, and there can be other such manufacturing related issues that affect performance. That’s why it is essential to deeply research the battery manufacturing processes and ensure rigorous quality checks during assembly. Li-ion batteries are also highly sensitive to natural elements such as temperature, and the other major threat comes from electrical abuse. The common electric abuse issues for the batteries are:
- external short circuit
- charging outside of the accepted
- over-discharge, and fast charging of over-discharged cells
- deep discharging
Repeated or prolonged electrical abuse can cause the SEI layer to become thicker and dendrite gets formed on the electrodes. Over a period of time, this can lead to a scenario where internal short circuits can occur, and even battery fire instances. The right BMS can reduce such occurrences.
The operational aspects of the BMS
BMS is primarily an advanced tech-driven electronic system that functions as battery intelligence. Its main functions are controlling the charge and discharge, thermal management, cell monitoring, cell balancing, fault diagnosis, battery health management, data acquisition and monitoring of the overall battery condition. BMS offers various advantages such as optimization of battery performance, and reducing the risks in EV operations.
Functions of a BMS
Data sharing – BMS monitors and stores crucial battery data, and shares it with the decision-making components of the system. For instance, measured voltage of each battery cell, current flows in parallel connected modules, and the temperature of each battery cell are some of the things that it acquires and shares the data about.
Thermal management – The Li-ion batteries need stringent temperature management. The battery shouldn’t get too cold.By ensuring that the temperature is increased to the safe operating range, the BMS can improve the efficiency of the batteries.
Battery safety – An advanced BMS comes equipped with various sensors that provide signals which protect the battery cells from problems such as overcharging, undercharge, insulation fault, uniformity fault, over-fast temperature surge, etc. The sensors transmit signals to the vehicle control unit and if it is a serious fault, the vehicle control unit can disconnect the battery pack from the power supply until the fault is rectified.
Charge and discharge control – Since the batteries have a fixed number of charge and discharge cycles, it is essential to effectively control each cycle to improve the battery’s performance throughout its life. Overcharging can be extremely harmful to the battery and the BMS helps in preventing it.
Battery condition monitoring – A good BMS integrates monitoring of various battery conditions such as State of Charge (SOC), State of Health (SOH), State of Power (SOP), and State of Energy (SOE). Etc.
Importance of battery hygiene
While the BMS monitors and controls various lifecycle processes of the batteries, there is also a need top practice various aspects of battery hygiene while charging and using them. For instance, temperature management is essential. Batteries should not be exposed to direct sunlight especially in summer. Similarly, they shouldn’t be placed on the floor while being charged and the charging cabinet must be in a space with ambient temperature control.
Conclusively, while it would not be accurate to say that the BMS can increase the operational range of a battery, it can certainly improve its lifecycle, and the output throughout its usable life!
(The author is Mr. Varun Goenka, CEO and Co- Founder, Chargeup and the views expressed in this article are his own)