環境低負荷半導体搭載型熱電発電モジュールの高出力・高耐久化に関する研究

• Project/Area Number: 12J07687
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 国内
• Research Field: 電力工学・電力変換・電気機器
• Research Institution: Tokyo University of Science
• Principal Investigator: 坂本 達也 東京理科大学, 基礎工学研究科, 特別研究員(PD)
• Project Period (FY): 2012 – 2013
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥1,900,000 (Direct Cost: ¥1,900,000); Fiscal Year 2013: ¥900,000 (Direct Cost: ¥900,000); Fiscal Year 2012: ¥1,000,000 (Direct Cost: ¥1,000,000)
• Keywords: 熱電変換 / 環境半導体 / マグネシウムシリサイド / プラズマ放電焼結 / 電極接合 / 熱電モジュール

Research Abstract

本研究は、中高温域(400～600℃)の排熱を直接電気エネルギーに変換する「熱電発電モジュール」を、環境低負荷な熱電変換材料Mg_2Siを用いて、実用レベルまで高出力、高耐久化することを主目的としている。これら目的の達成の為、H25年度の研究内容を以下のとおり実施した。
(1)高出力化 : Mg_2Siの熱電特性向上
1-1. 粗大Mg_2Si粒子を用いた焼結体の作製と評価
海外研究滞在先のCNR-IENIにて、Hall測定装置およびVan der Pawu法を用いて評価した結果、粒子を粗大化することにより移動度が向上し、電気伝導率が向上することが明らかになった。
1-2. 最大性能を得るためのアンチモン(Sb)の最適な添加量の探索
Sb添加量0～1.5at%の範囲内においてはSb添加量0.5at%前後にて熱電性能が極大値を示すことが明らかとなった。
(2)高耐久化 : Mg_2Siへの不純物添加による高温耐久性付与
2-1. 不純物添加Mg_2Siが高温で耐久性を有する原因の解明
熱重量分析装置によりMg_2Siの示差熱分析を行った結果、Sb添加量の増加に伴い酸化反応の開始温度域が高温側にシフトする傾向、すなわち高温耐久性が向上する傾向が見られた。
(3)高出力化 : Mg_2Siが発電した電力をより効率良く取り出せる電極材探索
3-1. Mg_2Siへの接合性が良好かつ低接触抵抗な電極材の探索
CNR-IENIが保有するPVD装置では様々な電極材料の接合も可能であったため、従来より接合可能であったNIに加え、CuやAlをMg_2Siへ蒸着させた。電極-Mg_2Si接合界面のSEM観察、ひっかき試験が実施され、今後の様々な電極材料との比較のために必要な基礎的なデータが得られた。
(4)高出力・高耐久化 : 新型発電モジュール構造の探求
4-1. 新型Mg_2Siモジュールの作製と評価
今年度、熱源から素子までの熱損失が少なく、かつ外力による素子折損が生じにくいモジュール構造を得るため、新規な熱接合部材を用い、かつトラス構造から着想を得た構造をモジュールに適用させた。有限要素解析により、この構造が耐久性の観点で有効なことが示された。

Strategy for Future Research Activity

(抄録なし)

Research Products

• [Journal Article] Selection and evaluation of thermal interface materials for reducing the thermal contact resistance in thermoelectric generators (2014)
  • Author(s): Tatsuya Sakamoto, Tsutomu Iida, Takeshi Sekiguchi, Yutaka Taguchi, Naomi Hirayama, Keishi Nishio, Yoshifumi Takanashi
  • Journal Title: Journal of Electronic Materials Volume: (出版準備中)
  • Peer Reviewed
• [Journal Article] Stress analysis and output power measurement of an n-Mg_2Si thermoelectric power generator with an unconventional structure (2013)
  • Author(s): Tatsuya Sakamoto, Tsutomu Iida, Yota Ohno, Masashi Ishikawa, Yasuo Kogo, Naomi Hirayama, Koya Arai, Takashi Nakamura, Keishi Nishio, Yoshifumi Takanashi
  • Journal Title: Journal of Electronic Materials Volume: (オンライン版のみ。冊子は出版準備中。) Issue: 6 Pages: 1620-1629
  • DOI: 10.1007/s11664-013-2814-6
  • Peer Reviewed
• [Journal Article] Development of an Mg_2Si unileg thermoelectric module using durable Sb-doped Mg_2Si Legs (2013)
  • Author(s): T. Nemoto, T. Iida, J. Sato, T. Sakamoto, N. Hirayama, T. Nakajima, Y. Takanashi
  • Journal Title: Journal of Electronic Materials Volume: 42 Issue: 7 Pages: 2192-2197
  • DOI: 10.1007/s11664-013-2569-0
  • Peer Reviewed
• [Journal Article] The use of transition-metal silicides to reduce the contact resistance between the electrode and sintered n-type Mg_2Si (2012)
  • Author(s): T. Sakamoto, T. Iida, Y. Honda, M. Tada, T. Sekiguchi, K. Nishio, Y. Kogo, Y. Takanashi
  • Journal Title: Journal of Electronic Materials Volume: 41 Issue: 6 Pages: 1805-1810
  • DOI: 10.1007/s11664-012-2073-y
  • Peer Reviewed
• [Journal Article] Examination of a thermally viable structure for an unconventional uni-leg Mg_2Si thermoelectric power generator (2012)
  • Author(s): T. Sakamoto. T. Iida, Y. Taguchi, S. Kurosaki, Y. Hayatsu, K. Nishio, Y. K.ogo, Y. Takanashi
  • Journal Title: Journal of Electronic Materials Volume: 41 Issue: 6 Pages: 1429-1435
  • DOI: 10.1007/s11664-012-1974-0
  • Peer Reviewed
• [Journal Article] Fabrication of large sintered pellets of Sb-doped n-type Mg_2Si using a plasma activated sintering method (2012)
  • Author(s): Y. Hayatsu, T. Iida, T. Sakamoto, S. Kurosaki, K. Nishio, Y. Kogo, Y. Takanashi
  • Journal Title: Journal of Solid State Chemistry Volume: 193 Pages: 161-165
  • DOI: 10.1016/j.jssc.2012.07.008
  • Peer Reviewed
• [Presentation] Magnesium oxide uptake in Mg_2Si thermoelectric pellets and their protection by thin coating at middle-high temperatures (2014)
  • Author(s): S. Battiston, S. Boldrini, A. Famengo, S. Fiameni, T. Sakamoto, A. Miozzo, A. Ferrario, S. Barison, T. Iida, M. Fabrizio
  • Organizer: Giornate sulla Termoelettricita 2014
  • Place of Presentation: Padua, Italy
  • Year and Date: 2014-02-19
• [Presentation] Adaptive thermal conjugation at the proximity of TEG contacting surface for mid-temperature operation (2013)
  • Author(s): Tatsuya Sakamoto, Tsutomu Iida, Takeshi Sekiguchi, Yutaka Taguchi, Naomi Hirayama, Keishi Nishio, Yoshifumi Takanashi
  • Organizer: 11th European Conference on Thermoelectrics : ECT 2013
  • Place of Presentation: Noordwijk, Nederland
  • Year and Date: 2013-11-19
• [Presentation] Current status of Mg_2Si to realize practical thermal-to-electric power generation device (2013)
  • Author(s): T. Iida, T. Sakamoto, Y. Taguchi, N. Hirayama, M. Ishikawa, T. Nemoto, Y. Kogo, K. Nishio, Y. Takanashi
  • Organizer: 11th European Conference on Thermoelectrics : ECT 2013
  • Place of Presentation: Noordwijk, Nederland
  • Year and Date: 2013-11-19
• [Presentation] Finite element approach for the evaluation and optimization of silicide-based TEG (2013)
  • Author(s): Alvise Miozzo, Stefano Boldrini, Simone Battiston, Stefania Fiameni, Alessia Famengo, Tatsuya Sakamoto, Simona Barison
  • Organizer: 11th European Conference on Thermoelectrics : ECT 2013
  • Place of Presentation: Noordwijk, Nederland
  • Year and Date: 2013-11-19
• [Presentation] Thermoelectric and mechanical properties of n-type Mg_2Si and the status of unileg TEGs (2013)
  • Author(s): T. Iida, T. Sakamoto, K. Nishio, Y. Kogo, N. Hirayama, M. Ishikawa, Y. Takanashi
  • Organizer: The International Union of Materials Research Societies, International Conference on advanced Materials (IUMRS-ICAM)
  • Place of Presentation: Qingdao, China
  • Year and Date: 2013-09-24
• [Presentation] Thermoelectric properties and durability at elevated temperatures of impurity doped n-type Mg_2Si (2013)
  • Author(s): Y. Oto, T. Iida, T. Sakamoto, R. Miyahara, A. Natsui, K. Nishio, Y. Kogo, N. Hirayama, Y. Takanashi
  • Organizer: Asia-Pacific Conference on Green Technology with Silicides and Related Materials : APAC-SILICIDE 2013
  • Place of Presentation: つくば、日本
  • Year and Date: 2013-07-28
• [Presentation] Direct thermal-to-electric energy conversion using environmentally benign Mg^2Si for reducing automotive CO2 emission (2013)
  • Author(s): T. Iida, T. Sakamoto, K. Nishio, Y. Kogo, N. Hirayama, Y. Takanashi
  • Organizer: Asia-Pacific Conference on Green Technology with Silicides and Related Materials : APAC-SILICIDE 2013
  • Place of Presentation: つくば、日本
  • Year and Date: 2013-07-28
• [Presentation] Stress analysis and output power measurement of an n-Mg_2Si thermoelectric power generator with an unconventional structure (2013)
  • Author(s): T. Sakamoto, T. Iida, Y. Ohno, M. Ishikawa, Y. Kogo, N. Hirayama, K. Arai, T. Nakamura, K. Nishio, Y. Takanashi
  • Organizer: IEEE 32st International Conference on Thermoelectrics : ICT 2013
  • Place of Presentation: 神戸、日本
  • Year and Date: 2013-07-01
• [Presentation] Improvement of thermoelectric properties of doped n-type Mg_2Si and component technology to realize a unileg thermoelectric generator (2013)
  • Author(s): T. Iida, T. Sakamoto, K. Nishio, Y. Kogo, N. Hirayama, M. Ishikawa, Y. Takanashi
  • Organizer: IEEE 32st International Conference on Thermoelectrics : ICT 2013
  • Place of Presentation: 神戸、日本
  • Year and Date: 2013-07-01
• [Presentation] Deterioration at elevated temperatures of Sb-doped Mg_2Si dependent on plasma activated sintering process (2013)
  • Author(s): K. Kato, T. Iida, T. Sakamoto, S. Soeda, K. Nishio, Y. Kogo, N. Hirayama, Y. Takanashi
  • Organizer: 2nd International Conference on Materials for Energy
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2013-05-14
• [Presentation] Mg_2Si排熱発電モジュール実現に向けた要素技術開発 (2013)
  • Author(s): 坂本 達也
  • Organizer: 日本熱電学会第16回研究会「国産デバイス・オンパレードII」
  • Place of Presentation: 東京、日本(招待講演)
  • Year and Date: 2013-03-01
• [Presentation] Manufacturing-directed fabrication processes based on a durable all-molten Mg_2Si source for the manufacture of the uni-leg structure of a thermoelectric generator (2012)
  • Author(s): T. Iida, N. Hirayama, T. Sakamoto, K. Nishio, Y. Kogo, Y. Takanashi
  • Organizer: IEEE 31st International Conference on Thermoelectrics, ICT 2012
  • Place of Presentation: Aalborg, Denmark
  • Year and Date: 2012-07-11
• [Presentation] Incorporation of a transition metal binder to assist sintering scalability of n-type Mg_2Si using a plasma activated sintering method (2012)
  • Author(s): N. Tsuji, T. Iida, N. Hirayama, T. Sakamoto, S. Kurosaki, Y. Hayatsu, K. Nishio, Y. Kogo, Y. Takanashi
  • Organizer: IEEE 31st International Conference on Thermoelectrics, ICT 2012
  • Place of Presentation: Aalborg, Denmark
  • Year and Date: 2012-07-11
• [Presentation] Thermoelectric properties and durability at elevated temperatures of transition metal doped Mg_2Si (2012)
  • Author(s): Y. Oto, T. Iida, T. Sakamoto, T. Mito, R. Miyahara, N. Hirayama, Y. Taguchi, Y. Mito, Y. Takanashi
  • Organizer: European Materials Research Society, 2012 Spring Meeting
  • Place of Presentation: Strasburg, Germany
  • Year and Date: 2012-05-17
• [Presentation] Electrical properties and durability of transition metal silicide electrodes adapted for n-type Mg_2Si prepared by a monobloc sintering method (2012)
  • Author(s): S. Soeda, T. Iida, T. Sakamoto, M. Tada, T. Sekiguchi, N. Hirayama, Y. Taguchi, Y. Mito, Y. Takanashi
  • Organizer: European Materials Research Society, 2012 Spring Meeting
  • Place of Presentation: Strasburg, Germany
  • Year and Date: 2012-05-17