Here in the manual p.28 it is described how to remove the battery:
https://www.documents.philips.com/assets...

A replacement battery is not available for purchase, but instead you are told to contact the service centre.
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If you need to replace the batteries of your Philips SpeedPro or Philips SpeedPro (Max) cordless hoover, please contact us (our service centre can replace them).
Please note that the 2-year warranty that applies to the Philips SpeedPro or Philips SpeedPro (Max) also covers the rechargeable batteries.
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https://www.philips.ch/c-p...

A call to Philips may provide more clarity.