Ordered the battery from iFixit, forgot to order the Pentalobe screwdriver. Nevermind, if you only do that stuff once (as I expect after 6 years with one battery) - don't spend the money on special equipment that cannot be used for anything else :)
Opening the macbook is easy (I have done that before to exchange the superdrive with a larger harddisk and the original HD with an SSD drive, and a couple of times to clean the fans), but the 3 screws on the battery are a pain.
What did the job for me: an old mini-flathead-screwdriver (approx. 2mm? - just slightly larger than the pentalobe) and a file. As none of my other screwdrivers would work with the ....pentalobes, i filed down the flathead (-)screwdriver so that it could get hold in 2 of the lobes - which did let me open and close these screws without a problem. My screws were not closed very tight though - if they are there is probably no way around the right tool.
Quando isso acontecer, você poderá ver um gráfico da reputação que ele adquiriu ao longo do tempo.
Aqui está uma prévia de como será o gráfico:
Nenhuma reputação adquirida ainda.