In order to realize reliable electrical connections in a stack-type thermoelectric power generating module, flexible sections were installed between lower-temperature-sides of thermoelectric elements. These sections were expected to play three important roles of interpolating different thermal expansions of the module components, enlarging heat removal area and penetration of any media through themselves. Then, a low-boiling-point medium was also applied for a high-speed direct heat removal via its phase change from the lower-temperature-sides of the thermoelectric elements in the proposing stack-type thermoelectric power generating module. No electrical disconnections inside the proposing stack-type thermoelectric power generating module were observed for more than 7 years of use, confirming the module stability. The power generating density from the proposing stack-type thermoelectric power generating module with the flexible sections and the low-boiling-point medium was improved about two thousands fold, compared to that without flexible sections and with water instead. (C) 2016 Elsevier Ltd. All rights reserved.