Your current passport is valid until the expiration date on the passport and independent of your spousal sponsorship application........if your passport expires, you will have to renew your passport.......your PR visa will not be issued on an expired passport.
If your spousal sponsorship is approved, you will receive PR visa and COPR..........the validity of your COPR is the earliest of your passport expiration date and the 1 year anniversary of your medical exam (e.g., if you did medical on Oct 12th 2018, 1 year anniversary will be Oct 12th 2019).
Assuming you apply today in 2018.......and the PR application is approved 1 year from today (i.e., in 2019).......and your passport expiration date is 2020........there is no problem......you only have a problem is your passport expires before your spousal sponsorship is approved.