In simple terms, a batchmate refers to a person who is in the same group or class as you. They are usually people who started or graduated from the same course, school, or program at the same time as you.
What has happened to our former batchmates? (ethanmama.com)
He told one of my batchmates, «I've got to say, this is a product I'm not at all interested in; I got ta tell you this is a business I'm not at all interested in»,» Bannon says. (inc.com)