Hi! Unless you're looking to buy a third-party battery, you have to call/message a Dell sales representative to order one.
I have a XPS 13 9300 that needs a new battery (model 722kk?) but the laptop is out of warranty and the Spanish Dell store does not carry this party. Are there reputable online stores in the EU? Or reputable third-party brands?  I see things on Amazon.es with battery brands I never heard of (Dentsing, CQCQ) and also online stores I can find nothing about (.adaptadores-pc.com). Thank You for your help!
Where to buy XPS 13 9300 Battery in Spain or EU?