I filed my taxes jointly with my wife in early 2020, is it possible to have my stimulus check sent to my bank account instead of hers which was listed on TurboTax?

Your banking information cannot be changed after your tax return has been filed and accepted.

Banking information does not go from TT to the IRS until you file your 2020 tax return and it is accepted. The IRS will begin to accept  and process 2020 returns at the end of January 2021.

You enter/change banking information in the FILE section before you file your 2020 return. Changing it on the TurboTax site does not do any good until you file your return and the IRS processes your return.   If they manage to start sending  out stimulus checks before you can change your information, we hope the IRS provides a way for you to change it with the IRS.  If your check goes to a wrong or closed account, it will be sent back to the IRS and then the IRS will mail a check to the address on your tax return.

suggest watching the IRS.GOV web site and their FAQs for the 2nd stimulus. 

They are talking about beginning the direct deposits as quickly as next week, so I suspect the ability to change bank accounts will be limited. 

Also, if it is a joint return, I do not recall there was an ability to split the stimulus payments between two bank accounts, which is what the phrasing of your question suggests. 

It MAY be possible to get the IRS to route your money differently - assuming Congress & the President get around to enacting this beast of a bill -  by setting up EFTPS to point to your preferred account.

EFTPS - Electronic Federal Tax Payment System® - at eftps.gov - to get started, then make a $1 estimated tax payment.  With luck, they'll recognize this as your most recent bank account and send the money there. 

here is the IRS' most recent FAQ on changing bank accounts for the stimulus: 

My bank account information has changed or was incorrect. Can I update it using the tool? (updated June 8, 2020)