There is one of them:
https://www.amazon.com/Mpow-Headphones-Rechargeable-Protective-Accessories/dp/B071FQ463D/ref=sr_1_13?ie=UTF8&qid=1502890193&sr=8-13&keywords=wireless+headphone+charging+case
Here is another one:
https://www.amazon.com/mophie-Capsule-External-Battery-Wireless/dp/B01L28LWLE/ref=sr_1_3?s=electronics&ie=UTF8&qid=1502891028&sr=1-3&keywords=wireless+headphone+charging+case