The picture included is what the battery looked like when taken out of a MacBook Air. You can imagine how badly the battery bent the metal casing of the MacBook Air, making it a challenge to remove some of screws.
In this case, the battery is from 2008, but we thought was so odd is how the battery inflated itself and made the laptop unusable. After we removed and replaced the battery, and installed a new hard drive as well, our MacBook Air got new life and working better than ever.
Keep in mind that old rechargeable laptop battery can go bad in many different ways over time. The worst cases are when they leak, or overheat internally. This battery didn’t do that.
If you got a good working laptop, you should consider changing the battery after 3 years. It will provide you with better charge time, and remove the issues of aging batteries.