How to find and target the right audience. Most specifically in the EV space

Im a founder of a startup that specialises in EV charging software and the struggle Im finding is finding leads. The ideal client is seeking to build a network of chargers and often these plans are something internal. I tried to contact a few EV charger brands for referrals but they were mostly uninterested. I know what we built has demand as we already have clients but Im lacking on strategy. When you’re in a niche industry, what’s the best way to do prospecting and building partnerships?