I'd replace the broken ones and then true the wheel with the proper spoke tension. There's videos available or bring it to a bike shop.
As already stated, it's the most common cause so replacement isn't going to solve the problem unless you true/tension properly.
Also check this from the article RftH linked
Seating at Bend
A common reason for spokes to fail on hub motors isn't because the motor puts extra strain on the spokes, or because the spokes aren't a thick enough gauge, it's because of fatigue failure from spokes that aren't held snug against the flange. If the spoke bend radius is too large or too far from the head, then it can flex up and down at the bend with each wheel rotation, eventually causing it to crack and fail.
This problem has been legendary with overseas built hub motors, and we had some Crystalyte shipments where about half the customers would experience spoke breakage on a recurring basis. Ideally the distance between the head and the bend in your spoke will match the thickness of the hub flange, and you won't have problems. But if not, there are two ways to address the situation. One is to insert a washer under the spoke head. The second way is to lace the wheel in an over/under pattern, such that the spoke tension compresses the bend part of the spoke into the flange.