I am new to circuits and electronics. I am creating my first project on 
embedded systems. The project is "Three-wheel car robot with motors," 
and I connected three lithium-ion batteries with the motor driver.
The issue was when I was working on the circuit, connected the 
batteries, and soon I noticed the high temperature of the battery 
holders and smoke from the words.
I think I have added more than the required batteries in the project, or 
the polarities were not right. I used the series connection of 
batteries. What may be the other issue? I have attached the battery 
connection in the attachment.
Is there anyone here who can discuss all the points about this project?