Acer A7003 ユーザーズマニュアル

These look like metal strips on the battery. This might happen, for 
example, when you carry a spare battery in your pocket or purse. 
Short-circuiting the terminals may damage the battery or the 
connecting object.
Leaving the battery in hot or cold places, such as in a closed car in 
summer or winter conditions, will reduce the capacity and lifetime of 
the battery. Always try to keep the battery between 15° C and 25° C 
(59° F and 77° F). A device with a hot or cold battery may not work 
temporarily, even when the battery is fully charged. Battery 
performance is particularly limited in temperatures well below 
freezing.
Do not dispose of batteries in a fire as they may explode. Batteries 
may also explode if damaged. Dispose of batteries according to local 
regulations.Please recycle when possible. Do not dispose as 
household waste.

Replace the battery with the same type as that which came bundled 
with your product. Use of another battery may present a risk of fire or 
explosion.