*Article* **A Portable Direct Methanol Fuel Cell Power Station for Long-Term Internet of Things Applications**

**Chung-Jen Chou 1,\*, Shyh-Biau Jiang 1, Tse-Liang Yeh 2, Li-Duan Tsai 3, Ku-Yen Kang <sup>3</sup> and Ching-Jung Liu <sup>3</sup>**


Received: 22 April 2020; Accepted: 7 July 2020; Published: 9 July 2020

**Abstract:** With regard to the best electro-chemical efficiency of an active direct methanol fuel cell (DMFC), the stacks and their balance of plant (BOP) are complex to build and operate. The yield of making the large-scale stacks is difficult to improve. Therefore, a portable power station made of multiple simpler planar type stack modules with only appropriate semi-active BOPs was developed. A planar stack and its miniature BOP components are integrated into a semi-active DMFC stack module for easy production, assembly, and operation. An improved energy management system is designed to control multiple DMFC stack modules in parallel to enhance its power-generation capacity and stability so that the portability, environmental tolerance, and long-term durability become comparable to that of the active systems. A prototype of the power station was tested for 3600 h in an actual outdoor environment through winter and summer. Its performance and maintenance events are analyzed to validate its stability and durability. Throughout the test, it maintained the daily average of 3.3 W power generation with peak output driving capability of 12 W suitable for Internet of Things (IoT) applications.

**Keywords:** direct methanol fuel cell; multi stacks; portable power; energy management system; Internet of Things; long-term; in-field test
