Ever wonder what's inside your Apple battery pack? It turns out that they're not that complicated inside, but it's amazing how much power these little cluster of cells can hold.
I took an iBook G3 (dual USB) battery apart on the advice of Coconut Battery which told me that after 496 load cycles, this battery had seen better days.
As you can see in this screen shot, the battery had 14 mAh Battery Capacity left compared to an Original Battery Capacity of 4000 mAh. In addition to lacking capacity the battery pack wasn't charging.
Time to take it apart!
Click through for a photo dissection of an Apple battery pack...
Figure 1: An iBook G3 rechargeable battery.
Figure 2: A view inside with the cover removed.
Figure 3: The underside of the exposed cells.
Figure 4: The top of the battery pack without the case.
Figure 5: The front of the PCB with the Foxconn battery terminal block.
Figure 6: The rear of the PCB
Figure 7: A single Sony Fukushima US18650GR cell.
Apple uses six Sony Fukushima US18650GR cells in the iBook battery pack. Each cell has a 18mm diameter and is 64.7mm long. Each cell is rated at 3.7V, 1800 mAh.
In order to get into the battery pack you'll need a special "3 wing" screwdriver, Usually a good small flathead works fine. Once the screws are removed the case is held on with some glue and requires some effort to remove. Once the case has been opened - be careful. The batteries contain a fair amount of electricity and shorting the terminals can easily cause a fire.
If you need a replacement battery for an older Mac, only purchase a new OEM battery from someone like Tekserve. As a licensed Apple Authorized Service Provider (AASP) they have access to Apple "service parts" like batteries for as long as five years after the product was announced - the legal limit for a California-based company.