Curved rechargeable lithium polymer cells from PowerStream
Amazon.com : PetSafe ScatMat Indoor Training Mat, 7 Correction Modes, Protect Your Furniture, Training Tool for Dogs and Cats, Curved Size Mat (50 in X 12 in) - Pet Proof Around Areas -
Bending Curved Folding Electric Bike Battery Box Bending Curved Bent Hidden Battery Box 36v Interior Reention Rapier Ir-ⅲ Box - Electric Bicycle Battery - AliExpress