With USB-C now common for power, you could power the laptop off a USB PD capable battery like this one: https://www.amazon.com/30000mAh-Portable-Charger-Output

With USB-C now common for power, you could power the laptop off a USB PD capable battery like this one: https://www.amazon.com/30000mAh-Portable-Charger-Outputs-Micro-USB/dp/B01F8IRIN0/ref=sr_1_1?tag=androheadl04-20&ie=UTF8&qid=1473422667&sr=8-1&keywords=aukey+30000mah+quick+charge+3.0 https://www.amazon.com/30000mAh-Portable-Charger-Outputs-Mic...