Looks Chinese. KRIKzz never uses TIANQIU batteries as far as I know. 
Is the battery really a strong evidence to say this is a clone?
Yes. KRIKzz is the only "official" manufacturer of the SD2SNES and buying one from either KRIKzz directly or through an official reseller is the only way to be guaranteed a working product. If you buy a new SD2SNES and it's a Rev. F or earlier, it is almost guaranteed to be a clone, as the board schematics for newer revisions were never released (although information on how to mod a Rev. F to a Rev. H is available).
The SD2SNES is open source, so Chinese-made ones are technically not "clones," but QA can be a massive problem (most commonly MSU-1 does not work due to bad soldering or dead chips, but there can be other issues), and warranty is not always available. You could get lucky and get a perfectly working one, but if you're spending that much money on a product already, I'd just go official, that way you get a guarantee that it will work properly.
Also most of the clones I've seen have that same label, but as previously mentioned, that is not a reliable indicator of it being a Chinese-made one, as someone could have replaced the shell or label.
And if the guy that made the SD2SNES (ikari_01) says it's a fake, it's probably a fake.
