Question about Kärcher Professional Backpack vacuum battery BVL 3/1 Bp

At the end of 2023 I bought a BVL 3/1 Bp incl battery 36V 50 at Galaxus for CHF 589.00 Now there are two BVL 3/1 without battery in the offer once for CHF 335.23 and once for CHF 495.00 Then there is a BVL 3/1 Anniversary for CHF 579.00 which will be available in April I would like to buy another BVL 3/1 incl. battery. What is the difference between CHF 335.00 and CHF 495.00?