What cells are these?

[Fallingwater]

I've dismantled the battery of an old Panasonic cell phone, and found these three NiMH cells:

The AA and AAA are for scale. The length is about 5/3AAA (one AA plus one 2/3AAA), but they are thinner than AAAs. I've never seen them before.

If the sticker on the battery is to be believed, they are 670mah cells.

I'm pondering whether to replace them with three AAAs and end up with a slightly hacked-up phone, or with three AAs for monster run time but a frankenstein phone.

 

[altis]

Could they be 9/5 AAA? That's 10.5mm diameter by 80mm long.

http://www.gpbatteries.com/html/techinfo/nimh.asp

Edit:
Sorry, I missed the bit about the thinner diameter. Perhaps they are some multiple of the AAAA which is 8.4mm in diameter. Look a bit further down the linked page under 'Standard Series'. There's nothing that sort of length though.

 

[Fallingwater]

Come to think of it, yes, they are the thickness of AAAAs.

I've decided to go for AAAs. AAs would make the phone too bulky to be pocketable.