The electric-car maker Tesla is raising $1.5 billion as it ramps up production of the Model 3 sedan, its first mass-market electric car.

The company said on Monday that it planned to offer senior notes due in 2025 and would use the proceeds from the offering to further strengthen its balance sheet during rapid scaling of production for the Model 3.

Tesla delivered the first 30 Model 3s to employees at the end of July. At the time, Elon Musk, the automaker’s chief executive and a founder, worried some investors when he warned that Tesla was about to embark on “at least six months of manufacturing hell” trying to get Model 3 production to 5,000 cars a week by December.

But last week, Mr. Musk clarified his comments, saying that Tesla should be able to overcome any supplier issues and other potential obstacles. Mr. Musk said investors should have “zero concern” about whether Tesla would be able to meet its goal of making 10,000 Model 3s a week sometime next year.