最好的手机电池或许是没有电池

随着手机、汽车和其他电力需求量较大的设备在我们的生活中日益普及，寻找更好的电池，可能会成为科技行业的终极军备竞赛。但华盛顿大学的研究人员或许已经颠覆了这个行业。研究人员宣布通过不使用电池的手机进行了首次蜂窝式通话。

这款原型机完全采用了市场上现有的零件，使用无线电源和小型太阳能充电器供电。当然这款手机确实非常简陋：除了收发语音信号，支持一副耳机外，该手机没有任何其他功能。既没有屏幕也没有内存。使用这款设备接通通话后，要按下一个按键才能开始对话。

它需要依靠附近的基站，将信号中继到手机的蜂窝网络。研究人员使用的是Skype。基站提供了手机的大部分运行电力，这些电力来自于无线信号。

这款手机可利用反向散射生成自己的信号。这项技术在无线射频识别芯片中已经很常见，这种芯片在现有的无线信号中输入新信息，然后反向反射到接收器中。

这款手机的一项重要创新是使用模拟语音编码而非数字编码，研究人员称，模拟技术可以大幅节省电力。用来扩大手机信号范围的补充电力，来自于光电二极管，实质上是一个微型太阳能面板。

简而言之，短期内别指望能在这款设备上一直玩《糖果传奇》。但研究人员预测，未来类似的无线技术将被广泛应用到手机信号塔或Wi-Fi路由器当中，使无电池通话变得无处不在，当然前提是我们不会完全放弃语音通话，转而选择短信、Snap Stories或其他通信方法。

6月30日发表的一篇研究论文详细介绍了这款手机。（财富中文网）

译者：刘进龙/汪皓

The quest for better batteries may be the ultimate technology industry arms race as phones, cars, and other power-hungry devices proliferate in our lives. But researchers at the University of Washington may have upended that equation, making what they say is the first cellular call from a mobile phone with, well, no battery at all.

The prototype phone, built with off-the-shelf components, runs on a combination of wireless power and tiny solar chargers. It’s certainly barebones: the phone can send and receive voice signals, drive a pair of head phones, and not much else. It has neither screen nor memory. Once you connect a call using the device, you have to push a button to talk.

The phone must rely on a nearby base station that relays its signal to the cellular network, in this case via Skype. The base station provides the bulk of the phone’s operational power, which the phone harvests from radio signals.

The phone generates its own signal using backscatter, a technique already common in RFID—as in radio frequency identification—chips that encodes existing radio signals with new information and reflects them back to a receiver.

One of the phone's key innovations is the use of analog rather than digital voice encoding, which the researchers say saves a substantial amount of power. Supplemental power to increase the device’s range comes from photodiodes, essentially tiny solar panels.

In short, don't expect to play endless games of Candy Crush on this device anytime soon. But the researchers envision a future where similar wireless technology is widely integrated into cell towers or Wi-Fi routers, making battery-free phone calls ubiquitous—assuming, of course, that we don't give up on voice calls entirely in favor of text messages, Snap Stories, or other communications methods.

The phone is described in detail in a research paper published on June 30th.