Unfortunately, each call in the batch is counted as an api call, it's just faster to call them within a batch since it will be 1 request. See here documentation on Facebook API:
Limits
We currently limit the number of requests which can be in a batch to 50, but each call within the batch is counted separately for the purposes of calculating API call limits and resource limits. For example, a batch of 10 API calls will count as 10 calls and each call within the batch contributes to CPU resource limits in the same manner.
Source: https://developers.facebook.com/docs/reference/api/batch/