[RedDevil]

The anode, cathode and everything in between are thin layers rolled up inside the cell. If you roll it out it can be over half a meter from end to end.

There is only one tab on the anode and cathode, usually somewhere in the middle of the unrolled strip. So the current in the cell does not just flow from the top of the cell to the bottom (or vice versa), but also up to half a meter sideways through the anode and cathode.

By extending the anode and cathode on either side of the roll and carefully folding them flat the current only has to move up or down the cell and no longer sideways through the anode and cathode. This limits the internal friction in the cell, which increases its efficiency and power output and reduces its cooling needs.

Because the cells now need less cooling they can grow in diameter. This greatly expands the capacity per cell, while the production costs of the cell grow less quickly; so the pack can be made with less and relatively cheap cells which of course further reduces cost.

As a bonus the bigger diameter makes the cells more resistant to lateral deformation, so they can become part of the structural support system. Instead of being embedded in the chassis the battery pack now is a structural part of the chassis.

Not having tabs is a small thing in itself but it enables a string of developments which all combined have a huge impact.