Before you write your business plan, identify what it is you plan to accomplish by writing it. Sustainability? Growth? A resource to assist in grant writeups? Effective utilization of team resources (spending money well)? Effective recruitment of mentors and students? Consistently in team procedures? To Help students understand how the business side of your team works?.....
There are many more reasons than I listed, but those are just a few.
Your business plan can be whatever you want it to be. There is no set list of things it must include or can't include. I would strongly discourage using a template that doesn't achieve what it is you want most effectively. And because every team has a different plan, with most being hard to access, finding a template to match your goals probably isn't the best use of your time.
With a list of things you want your plan to accomplish in mind, read over other team's business plans and see how they accomplish some of your objectives.
I would look for some business plans of teams that have won Entrepreneurship Award, and others that you think might match your structure, size, and the objectives you hope to accomplish through the plan.
We Have won EA the past three years, and I would encourage you to take a look at our plan on our website
team2537.com but I would recommend not using it strictly as a template unless you feel it accomplishes most of your team's objectives effectively.
Would like any help with your plan's structure, someone to look over a draft, or anything else, feel free to PM me.