Soldering battery lips
Often the metal at the contacts will have a thin chrome plating. Scrape that with some fine sandpaper, then flux and solder.
However, heat is a risk, and if those batteries did not come with solder tabs, then soldering wires on would most likely violate warranties besides possibly exploding or just degrading. 
If you must solder, use the highest solder iron temperature, so that the soldering is a really quick job.
Standard AA spring-loaded battery cases are pretty inexpensive, that would be my choice for batteries like the one indicated. An option would be to take the "negative side" spring off two cases, and use one at each end, replacing the flat metal contact typically found on the positive side.