Comment by vatys

Yes, commonly referred to as a “battery emulator” in EE labs for mobile devices. Some are lab grade test equipment from big name vendors, and some are home-grown concoctions which use a power supply, capacitors, and adjustable load to shunt the power when the device tries to “charge” the battery. If a battery charging circuit is running, it’s generally not enough to just provide a DC power supply, it actually needs to be able to both source and sink current. But if the battery charger can be disabled, then a high current power supply, lots of capacitors, and a good short connection can be enough to replace a battery for a phone/tablet.