Ford transit key fob problem

[silverdale]

A friend has recently bought a 59 plate Ford Transit van and the key fob isn't working see picture.
Is this a rechargeable battery or a standard button battery ?.
If it's the rechargeable type were can he buy a rechargable battery. This type doesnt doesnt simply slot open so I'm sure I'll end up wrecking the case before I go inside.
Here's the key in question

 

[avid]

The black section pulls apart from the blue section( it will be tight use a small flat screwdriver). Once separated you can separate the blue section which contains the button battery.

 

[silverdale]

He came round today and I took a look. I have a fob tester so I changed the CR2016 battery and the fob was flashing fine
He tried it on the van and at the same time I .monitored it with the tester, it still didnt work.
He's just bought the van so I think it's the van itself at fault and not the fob

 

[john!]

try resetting the fob
https://remotekey.co.uk/ford/programming-ford-remotes/

 

[Bombenleger1337]

you need to pair the fob with the car again