Only the seller can tell you for sure, but it's not brand-new if it's genuine.  It was made in February, 2018.

Where did you get the battery? If it is not from Dell or Dell Parts it is most likely not a brand new genuine Dell battery. Lots of scams with batteries from Marketplaces like Amazon, Ebay, private online sellers, etc. Used batteries and counterfeits are sold as new. Labels can be fake. 

See this: https://www.dell.com/en-us/work/shop/partsbytype/batteryselector

If Dell does not have a battery for your model, try using the adapter alone with the battery removed. That works on recent models. https://www.dell.com/support/article/en-us/sln128667/dell-laptop-battery-frequently-asked-questions?lang=en

@ejn63  Hi,can you tell me which part of the serial number refers to the date you mentioned

Anyone from dell can confirm if its a genuine serial number? Or anywhere we can check it ourselves?

Thank you

@Mary G  Hi,i had to buy the battery from a seller as dell dont list one for my laptop

Also using the laptop constantly plugged in is not feasable as i need it to be portable

Thanks

When i checked in dell power manager lite,it says dell battery:yes

So it seems to be showing as a dell battery

The 88I is the date code -- 8 = 2018.

@ejn63 Hi,not sure where you are seeing this?

Do you mean where it says B8I? there is no 88I that i can see

Does B8I signify 2018 somehow?

Thanks

That first digit is a numeral - 8 corresponds to 2018.

The B is actually the second field, which actually means November (1 is January ... 2 Feb, etc then A, B).

Thanks.Makes sense about the letters corresponding to a month

Do you think that if it wasnt a genuine battery,that it would still show up in dell power manager as saying it was dell?

Thanks

There are a number of reasons why it might - the only source of the answer you're seeking is the seller.

At minimum, since it's a 2-year old battery it may not have as long a life as a fresh battery would.  Lithium ion batteries begin to age the day they're produced, whether or not they're being used.  That would be a bigger concern than that it's a genuine battery or not.