This document discusses cell balancing techniques for electric vehicle batteries. It begins with an abstract stating that battery life can be improved by equalizing the energy levels of individual cells through either passive or active cell balancing. The introduction explains that manufacturing inconsistencies can cause cell voltage and state of charge imbalances over time, degrading the battery life and creating safety issues. Active cell balancing is discussed as transferring energy from higher voltage cells to lower voltage cells. The conclusion states that the presented system is able to actively balance 16 battery cells by monitoring voltages and transferring energy between cells using a microcontroller and relays.

1. Cell Balancing techniques in
EV’s
Project By:
1. Vinayak Bhoir
2.Satyam Deokate
3.Umakant Pune
UNDER THE GUIDANCE OF
MRS. VARSHA SURWASE
VIDYA PRATISHTHAN'S KAMALNAYAN BAJAJ INSTITUTE OF ENGINEERING &
TECHNOLOGY

2. Abstract
Battery is the heart of electric vehicle and a way
of improving the battery life is to equalize the energy of its
cells. This can be done by either dissipating excess energy in the
form of heat (passive cell balancing) or charging the low voltage
cells through high voltage cells (active cell balancing)

3. Introduction
 Due to manufacturing inconsistency, there are slight dif-
ferences in the cell voltages or state of charge, cell internal
resistance, self-discharge capacity
 As the cells are connected in series to form a battery pack these slight differ-
ences causes imbalance in the battery, and they are magnified
with each charge and discharge cycle
 This imbalance causes cell degradation, shortening of battery lifetime and
safety hazards due to over-charge or deep-discharge
 In order to resolve these problems, energy in the battery needs to
be distributed uniformly.
 This can be done by dissipating extra energy from the overcharged cell as heat through
bleeding resistor or transferring the energy from the cell having higher
cell-voltage to the cell having less cell-voltage

4. Why Active Cell Balancing

5. Components
Li-ion
Battery
Pack
ESP32-
Microcon
troller
PWM
Controller
Digital to
Analog
Controller
Display

6. Flow Chart

7. Block Diagram
Arduino uno
Power supply
Relay switching
ckt
Led indicator Battery bank 1
buzzer
Battery bank 2
LCD display

8. Advantages
Advance Microcontroller based handling of BMS.
Thermal Management Protection-Temperature.
Electrical Management Protection-Voltage.

9. Conclusion
The overall system is able to monitor the
voltage of all cells with high accuracy up to 2 mV and perform
the process of active cell balancing. Initially the balancing
algorithm is tested on only one cell at different balancing
currents and it is concluded that at higher balancing current
the cells are balanced quickly. After the balancing control
algorithm is validated for one cell, balancing of sixteen cells
is performed. To validate the algorithm for sixteen cells the
balancing is performed at constant balancing current of 4 A.
However, balancing current can also change according to cell
voltage deviation.

10. Reference
 G. Ren, G. Ma, and N. Cong, “Review of electrical energy storage
system for vehicular applications,” Renewable and Sustainable Energy
Reviews, vol. 41, pp. 225-236, 2015.
 M.-Y. Kim, C.-H. Kim, J.-H. Kim, and G.-W. Moon, “A modularized
bms with an active cell balancing circuit for lithium-ion batteries in v2g
system,” in Vehicle Power and Propulsion Conference (VPPC), 2012 IEEE.
 L. Valda and K. Kosturik, “Comparison of li-ion active cell balancing
methods replacing passive cell balancer,” in 2015 International Confer-
ence on Applied Electronics (AE). IEEE, 2015, pp. 267-270.

11. THANK YOU