Design of Charging Module and Charging Balancing Module for Electric Vehicle Battery Pack
1. Design of Charging Module
and Charging Balancing
Module for Electric Vehicle
By:
Muhammad Suhaimi Bin Adanan Battery Pack
Supervisor:
Mohd Rezal Mohamed
2. INTRODUCTION
• Any electric car that uses batteries needs a
charging system to recharge the batteries. The
charging system has two goals:
– To pump electricity into the batteries as quickly as
the batteries will allow
– To monitor the batteries and avoid damaging them
during the charging process
3. OBJECTIVES
• To design a charging module and charging balancing
module for EV battery pack.
• To ensure that all cells capacity are balance during
charging.
• To avoid overcharge during battery charging.
4. PROJECT SCOPE
• This project will analyse the charging module and
charging balancing module for electric powered
Proton Saga BLM.
• Battery type: Lithium Iron Phospate (LiFePO4)
• 96V 100Ah
5. PROBLEM STATEMENT
• If the charging process is done without charge
balancing, the batteries are not at the same SOC.
• In this case, the batteries with less restored
energy will be exhausted first when the battery
bank is reused.
• For this reason, charge balancing should be
included in the charging control of series-
connected batteries.
7. SOC MEASUREMENT
The state of charge (SOC) is the
present capacity of the battery. It
is the capacity that remains after
Current
Sensor
discharge from a top-of-charge
Load condition.
i(t) dq
+ - i (t )
dt
dSoCT dq
Battery Qt
i(t )dt
t
SoCT (t ) QT i( )d
0
10. THE PROS AND CONS OF EACH
CHARGING METHOD
Method Advantages Disadvantages
Constant current method Has ability of limited current It is easy to overcharge in
to prevent the over current later stage
of initial charge
Constant voltage method Has ability of limited voltage Easy to over current in initial
to prevent the over voltage stage
Constant current / constant Can limit voltage and current Charge time is too long
voltage method
Pulse charge method Can reduce the polarization Control is complex
to prevent the battery
temperature rise
ReflexTM charge method Can reduce the polarization Control is complex
to prevent the battery
temperature rise
15. Voltage B1
Sense
Voltage B2
Gate Driving Signal Sense
Voltage B3
Sense
Signal
Voltage
Conditioning
Sense
B4
Voltage B5
Sense
Single Chip MUX
Processor ADC Voltage
B6
Sense
Voltage
Sense
B7
Voltage
Sense
B8
Voltage
Sense
B9
Voltage
Sense
B10
Voltage
Cr
Block diagram of control unit Sense
16. Start Charging
Wait for Tvdp
Read battery
voltage, Vn
Yes
For all n,
Terminate charging
Voltage Vn=Vfull
Detecting No
Phase 1 N
Vavg n 1
Vn
N
No For any n
Vn > V avg
Yes
Activate PWM module
n, calculate duty ratio
Reset ta
Charge
Balancing For activated modules, process
Phase PWM signals
Yes
ta < tcep
Control flow chart
No
18. PROJECT PLANNING
RESEARCH ACTIVITY JAN FEB MAR APR MAY JUN JUL AUG SEP DIS
Discuss FYP title with
supervisor
Title submission and
presentation
Literature review
Thesis dissertation 1
(Ch. 1, 2 and 3)
Project Simulation
Experimental setup
Experimental
implementation
Result discussion
Thesis dissertation 2
(Ch. 4, 5 and 6)
Report submission /
Final Presentation
Battery pack designs for Electric Vehicles (EVs) are complex and vary widely by manufacturer and specific application.Battery packs for all electric drive EVs can contain several hundred individual cells.The large stack of cells is typically grouped into smaller stacks called modules.Batteries in EVs must be periodically recharged.BEVs most commonly charge from the power grid (at home or using a street or shop recharging point), which is in turn generated from a variety of domestic resources, such as coal, hydroelectricity, nuclear and others.
10 cells is connected in series.Charging balancing module is used to make sure that all 10 cells have same capacity during charging.Charging module is used to charge the cells.