Max no. of Power banks allowed in Carry on - Air China

Air China seems to have a policy in place for the batteries (or generally termed power banks) 10000mAh should amount to 36WH or 50Wh depending on whether the batteries are rated 3.6V or 5V. However still, policy says that 2 batteries are allowed that shouldn't exceed 160Wh.

EDIT: As identified by @DCTLib below, only two spare batteries are allowed in cabin baggage. So, the 4 additional ones you have will probably be denied when you take them onboard.

My suggestion: If you are coming with 2 checked bags, have 2 packs placed in each bag and carry 2 with you in your cabin baggage. I read the terms carefully and doesn't seem like there should be a problem because in no bag, there will be more than 2 battery packs which is otherwise the allowed limit. Not sure if there any specific wording that these can be carried only in cabin or checkin. Make sure the ones in checkin bags are packed in their original packaging.

If you're not coming with 2 checked bags and have only one, risk it by packing 3 in checkin and 3 in cabin (you can split cabin in say laptop bag and the cabin bag?) and still get these transported safely. Worst case, you may have to leave 1 behind at max. It is unlikely that they take away the battery packs from checked in luggage.