ON THIS WIKI
When held in the hotbar (similar to a bucket) and right clicked on a liquid (Water, Lava, Fuel) they will gather the liquid in the cell and can stack with similar cells up to 64. Although this works similar to buckets, once the liquid is collected, it cannot be placed, instead it must be used in a recipe, and sometimes, used in an extractor to regain an empty cell.
In Direwolf20 1.6.4 the Empty Cells are made in a Metal Former and requires 1 tin plate to make 3 cells giving 12 cells compared to the original recipe.
If GregTech is enabled, the recipe for empty cells will only output 4 instead of the original 16.
Empty Cells are used in many recipes of Industrial Centrifuge and Industrial Electrolyzer, where they are returns as a product, but in many other recipes, the empty cells are not returned, and are lost.
Note: The bucket is not consumed in any of these recipes.