CCCV constant current constant voltage

Salah king

Joined Oct 27, 2022
3
Hello
I would like to understand the behavior of the CCCV control, which is used to charge and discharge the battery.
as I know the CC will work at the beginning till the voltage of the battery reaches to the desired voltage then CC will stop,
the charging mode is switched to CV, and converter operates, keeping the output voltage constant while current starts decreasing.

If there any demo model (MATLAB file) can describe this behavior more will be very helpful.

BobTPH

Joined Jun 5, 2013
6,082
What more is there to describe? Your post already says everything you need to know, other than the specific current and voltage which depends on the type and capacity of the battery.

MisterBill2

Joined Jan 23, 2018
13,805
Post #1 is only about the battery charge CCCV, which is also used elsewhere.
Many LED arrays are fed with constant current

ronsimpson

Joined Oct 7, 2019
2,540
f there any demo model (MATLAB file) can describe this behavior more will be very helpful.
I don't use MATLAB. Take a bench power supply and set the voltage to 12V and the current limit to 1A. That is CVCC.

Audioguru again

Joined Oct 21, 2019
5,420
You did not say what kind of battery but you probably describe a Lithium-ion battery.
Go to www.batteryuniversity.com and read about the CC and CV for charging it.

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KeithWalker

Joined Jul 10, 2017
2,620
A single cell Lithium-ion battery is usually charged to 4.2V, so a 4.2VDC supply is used. It has a current limiter, set to limit the current to the maximum recommended charging current for the battery. If the battery is discharged, the terminal voltage will be less than 4.2V so it will draw the maximum available current from the supply. As the battery charges, and the terminal voltage approaches 4.2V, the current will decrease until the battery voltage equals the supply voltage, when no more current will flow.
In an actual battery charger, the supply cuts off when the current falls to 1/10 of the maximum charge current.

crutschow

Joined Mar 14, 2008
31,129
If there any demo model (MATLAB file) can describe this behavior more will be very helpful.
Here's a simple LTspice functional simulation of charging a battery, but don't know how that might translate to MATLAB.
R1 and C1 are a simple battery model.
C1 represents the battery capacity, and R1 represents the charge current when the battery reaches full charge.

The battery is charged at 1A constant-current (red trace) until the voltage reaches the V1 10V (green trace) causing the switch S1 to close, at which point the S1 switch shunts the I1 current, leaving the battery at that voltage.

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Audioguru again

Joined Oct 21, 2019
5,420
The graph I posted shows that when the lithium battery voltage equals the supply voltage then the battery is still charging for a fairly long time before its charging current slowly drops to a low amount and then the battery is fully charged and the charger shuts off. A lithium battery must not be trickle charged and the lifetime is less if maximum charging current (and resulting max heating) is used.

Salah king

Joined Oct 27, 2022
3
You did not say what kind of battery but you probably describe a Lithium-ion battery.
Go to www.batteryuniversity.com and read about the CC and CV for charging it.
is the lead acid battery having different profile charging?

Audioguru again

Joined Oct 21, 2019
5,420
is the lead acid battery having different profile charging?
An old lead-acid battery is completely different to a modern lithium battery.

Salah king

Joined Oct 27, 2022
3
An old lead-acid battery is completely different to a modern lithium battery.
I meant the difference on the profile charging plot. thanks

KeithWalker

Joined Jul 10, 2017
2,620
Lead-acid batteries have a very similar charging profile to Lithim-ion batteries but with different terminal voltages and internal resistances.

crutschow

Joined Mar 14, 2008
31,129
Lead-acid batteries have a very similar charging profile to Lithim-ion batteries but with different terminal voltages and internal resistances.
Also Lithium-ion batteries generally don't like trickle-charge current at the end of charge.