Since we learned about pouch batteries last time, we will check out the assembly process of cylindrical batteries this time.
These are safe, mass-producible batteries with the most familiar form to us. How are they produced? Let’s find out with an infographic.
Winding Method
First, a cathode roll and an anode roll produced through the electrode manufacturing process and two separator rolls are attached to a machine called “winder.” Then, they are wound around a mandrel and cut to proper length with the shape of a jelly roll.
Tab Welding
Now that a jelly roll is formed through the winding method, an aluminum tab and a copper tab are welded onto the uncoated parts of cathode and anode respectively.
Tab Shaping & Canning
Next, the jelly roll is put in the cylindrical battery can. In this process, the anode tab is bent into an L shape and welded to the bottom of the can, while the cathode tab remains unbent and is welded to the top of the can. After that, the jelly roll in the can is fixed by beading*.
*Beading: Resistance welding. Also called spot welding, as the welding beads look like spots.
Electrolyte Injection
Then, a vacuum state is created in the inside of the can and required amount of electrolyte is injected into it through a nozzle. And the can is pressed to let the electrolyte fill the pores of the electrode. When this process is over, the last process is to crimp* the top cap and the can.
*Crimping: Sealing the cap by compressing it.
An insulated tube is put on the completed cylindrical battery to separate the cathode and anode and prevent short circuits. The shape of a cylindrical battery as we know it is formed in this stage. Next time, we will examine formation, a step to give electrical properties to assembled batteries.