Laptop manufacturers want to slim down laptops and make them lighter-weight in response to consumer demand. Unfortunately, the components that make a battery removable do the opposite — they take up more space and add more weight to the design of the unit. If the manufacturer knows the battery will not be removable, they can literally fit the battery packs anywhere there is space to accommodate them within the unit. But, if the battery pack is removable, then they have to make sure there’s enough space for a dedicated battery compartment to fit, and the battery pack itself has to be encased in a plastic shell to keep the battery protected when it is outside the machine.