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 cathode tab (aluminum) is bent into a hook shape and the anode tab (copper) into an L shape. The former is welded onto the top of the can and the latter onto the bottom of it. 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.