That looks like it’s going to be a custom battery pack. Here’s a link with instructions for ordering a custom pack: Custom Battery Packs - Support - Engineering and Component Solution Forum - TechForum │ Digi-Key (digikey.com)
Now your specific need isn’t listed in the style, so make sure to state the layout when you email custom.orders@digikey.com. They may ask for a drawing, but be as clear as possible with as much information as you have and they should be able to give you a price and lead time.
Hope this helps!