Could you check this Li-ion charging circuit?

In summary: There is no ground for the model. Without ground it will run very slowly due to current sources in the LT317 model.I worry about current limit to the base of Q1.Where is the model for the Li ion battery, what voltage is the battery?There is no ground for the model. Without ground it will run very slowly due to current sources in the LT317 model.
  • #1
emtae55
24
0
TL;DR Summary
I made a Li-ion charging circuit with LTspice, and I wonder if it works well. Could you check this??
Can secondary cell can be described in circuit simulator?? With other symbols like capacitor. Also I wonder if there's a program that provide secondary cell(like Li-ion battery). Please help me
 
Last edited:
Engineering news on Phys.org
  • #2
It depends what you mean by “electric simulator”.
SPICE has a floating voltage source.
 
  • #3
emtae55 said:
Summary:: Can secondary cell can be described in electric simulator?? With other symbols like capacitor.

Can secondary cell can be described in electric simulator?? With other symbols like capacitor. Also I wonder if there's a program that provide secondary cell(like Li-ion battery). Please help me
What's a "secondary cell"? Do you mean a rechargeable battery? If so, just do a Google search on SPICE simulation rechargeable battery.
 
  • #4
We often use equivalent circuits to represent real life devices. For example, a transformer.

But we can't help you to find an equivalent circuit without much more specific information on the device and the application. Do you need to simulate one second? Hour? Year?
 
  • #5
anorlunda said:
We often use equivalent circuits to represent real life devices. For example, a transformer.

But we can't help you to find an equivalent circuit without much more specific information on the device and the application. Do you need to simulate one second? Hour? Year?

I want to know the time for charging it.
 
  • #6
The capacity of a rechargeable chemical battery will be specified in amp*hours. If you know the charging current, then you can calculate the time needed to recharge an empty battery.
Hours = (amp*hours) / (charging current)

If you want to simulate the circuit of the charger and battery condition over time, then you should specify the simulator you will use.
LTspice is the most widely used circuit simulator available for free.
https://en.wikipedia.org/wiki/LTspice
 
  • #7
Baluncore said:
The capacity of a rechargeable chemical battery will be specified in amp*hours. If you know the charging current, then you can calculate the time needed to recharge an empty battery.
Hours = (amp*hours) / (charging current)

If you want to simulate the circuit of the charger and battery condition over time, then you should specify the simulator you will use.
LTspice is the most widely used circuit simulator available for free.
https://en.wikipedia.org/wiki/LTspice
I'd like to use LTspice, but I can't find the Li-ion battery component. Would you find me the component(or library)? Thanks.
 
  • #8
  • #11
The thing about circuit simulators is that they do exactly what you set them up to do. They are absolutely not effective at telling you about the components in your circuit. That is the information that you must provide; you must characterize and model your battery. The circuit simulators can tell you how that will interact with other components that you have input into the model. If you program it incorrectly (i.e. unrealistic component models) it will happily simulate the wrong circuit and give the wrong answers; i.e. it will do exactly what you tell it to do.

Batteries of all sorts are typically modeled as capacitors, resistors, voltage sources, etc. If you are lucky you may be able to get access to a battery model that someone else created, but there is no guarantee that it will match the characteristics of your battery.

Circuit simulators are a poor substitute for understanding what you are building, particularly when it comes to individual components of that circuit.
 
  • #12
I made a Li-ion charging circuit with LTspice, and I wonder if it works well. Could you check this??
whole.png

potentiometer.png

battery.png
 
  • #13
If you take the file.asc and rename it file.asc.txt you can then attach it to your next post, then we can run it to test it. You can do the same with a file.plt by appending .txt
 
  • #14
There is no ground for the model. Without ground it will run very slowly due to current sources in the LT317 model.
I worry about current limit to the base of Q1.
Where is the model for the Li ion battery, what voltage is the battery?
 
  • #15
Baluncore said:
There is no ground for the model. Without ground it will run very slowly due to current sources in the LT317 model.
I worry about current limit to the base of Q1.
Where is the model for the Li ion battery, what voltage is the battery?
Well, because i can change the battery to 18650(standard), so you might not to be worry about that.
 
  • #16
emtae55 said:
Well, because i can change the battery to 18650(standard), so you might not to be worry about that.
I made three points, worry about which?

What if the battery becomes short circuit? then regulator produces 1.2 volts and current is not limited, so the base of Q1 is destroyed.

What range of voltages can the battery be?
 
  • #17
Baluncore said:
I made three points, worry about which?

What if the battery becomes short circuit? then regulator produces 1.2 volts and current is not limited, so the base of Q1 is destroyed.

What range of voltages can the battery be?
Because it's a 18650, it might be about 3.7V.
Also, the max current of Q1 is 50 nano A.
 
Last edited:
  • #18
emtae55 said:
Also, the max current of Q1 is 50 nano A.
Where do you get that 50 nA value from? Which terminal, under what conditions.
The Q1 collector current during limiting is 1.2V / 470R = 2.55 mA. The base current is then about 25 uA.

But when the battery fails short, (or the terminals are accidentally shorted), the LM317 and battery current will be guaranteed to be more than 1.5A by the LM317 internal limiting, so there will be at least 1.5 volts across the 1R0 current sense resistor, in parallel with the forward biassed base-emitter PN junction of Q1. That is why LM317 data sheets usually recommend a series resistor of about 100R to the base of the Q1 current limiter. That will limit the Q1 base current to about 10 mA which should not destroy the junction.

The LM317 dropout voltage is about 2 volts, the Li cell being charging will be about 3.8V, the voltage drop across the current sense resistor will be about 0.7V, the 1N4001 drop is 0.9V which gives a total of 7.4V, so the charger will need more than the 6 volt supply you have specified.
 
  • #19
[Mentor Note -- Two threads on the same subject merged into one]
 
  • #21
@emtae55
I see you have now taken your question to the LTspice group.
https://groups.io/g/LTspice/message/123869
That group works with LTspice operation and functionality rather than circuit design advice.

We are not mind readers.
If you want circuit advice you will need to answer the questions asked.
 

Related to Could you check this Li-ion charging circuit?

1. How does the Li-ion charging circuit work?

The Li-ion charging circuit works by regulating the flow of current from the power source to the battery. It uses a series of components, such as resistors and capacitors, to control the voltage and current levels to ensure safe and efficient charging of the Li-ion battery.

2. Is it safe to charge a Li-ion battery with this circuit?

Yes, as long as the circuit is designed and implemented correctly, it should be safe to charge a Li-ion battery with it. It is important to follow proper safety precautions and use high-quality components to prevent any potential hazards.

3. How long does it take to fully charge a Li-ion battery with this circuit?

The charging time of a Li-ion battery depends on its capacity and the charging current of the circuit. Generally, it can take 1-2 hours to fully charge a Li-ion battery with a standard charging current of 1C (where C is the battery's capacity in Ah).

4. Can this circuit be used for fast charging a Li-ion battery?

It depends on the specific design and capabilities of the circuit. Some Li-ion charging circuits are designed for fast charging, while others are not. It is important to consult the circuit's specifications and follow recommended charging guidelines for fast charging.

5. How can I tell if the Li-ion battery is fully charged?

Most Li-ion charging circuits have a built-in mechanism, such as an LED indicator, to show when the battery is fully charged. Additionally, the battery's voltage and current levels can also be monitored to determine when it has reached its maximum capacity.

Similar threads

  • Electrical Engineering
Replies
3
Views
565
  • Electrical Engineering
Replies
13
Views
1K
Replies
10
Views
2K
  • Electrical Engineering
Replies
10
Views
8K
Replies
4
Views
1K
Replies
1
Views
1K
  • Materials and Chemical Engineering
Replies
0
Views
699
  • Materials and Chemical Engineering
Replies
2
Views
1K
  • Electrical Engineering
Replies
4
Views
2K
  • Electrical Engineering
Replies
4
Views
2K
Back
Top