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Mapping Japan’s innovation activity in hydrogen technologies: An approach based on patent network analysis Cover

Mapping Japan’s innovation activity in hydrogen technologies: An approach based on patent network analysis

International Journal of Management and Economics
Volume 62 (2026): Issue 1 (March 2026)
By:  and    
Open Access
|Jul 2026
Figures & tables

Figures & Tables

Table 1

Data collection process.

StepPATENTSCOPE advanced searchNumber of patents
1FP:( “alkaline electrolysis” OR “alkaline fuel” OR “ammonia cracking” OR “anion exchange membrane” OR “automotive fuel cell” OR “aviation fuel cell” OR “carbon capture utilization” OR “ccus” OR “coal gasification” OR “fuel and electrolysis cell” OR “fuel cell truck” OR “fuel cell vehicle” OR “hydrogen carrier” OR “hydrogen distribution” OR “hydrogen fuel” OR “hydrogen gas turbine” OR “hydrogen generation” OR “hydrogen internal combustion engine” OR “hydrogen liquefiers” OR “hydrogen production” OR “hydrogen refueling station” OR “hydrogen storage” OR “hydrogen tank” OR “hydrogen transformation” OR “hydrogen use” OR “hydrogen vessel” OR “hydrogen-based fuel” OR “oil reforming” OR “proton exchange membrane” OR “shipping fuel cell” OR “soec” OR “solid oxide electrolyzer cell” OR “steam reforming” OR “synthetic fuel” OR “synthetic methane” OR “water electrolysis” OR “water electrolyzer” ) 98,099
2AND PA:( “asahi” OR “electric power development” OR “eneos” OR “hitachi” OR “honda” OR “iwatani” OR “j-power” OR “k line” OR “kawasaki” OR “marubeni” OR “matsushita” OR “mitsubishi” OR “nippon oil and energy” OR “nissan” OR “panasonic” OR “sanyo” OR “shell japan” OR “sumitomo” OR “tokyo gas” OR “toshiba” OR “toyota” ) 10,789
3AND DP:[1960 TO 2019]9,437
4AND DP:[2020 TO 2024]1,352

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b).

Graph 1

Annual number of new patents, 1960–2023 (publication date).

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b).

Table 2

Prominent patent offices and patent applicants.

RankPatent officeNumber of patentsRankPatent applicantNumber of patents
1Japan6,7531Honda Motor Co Ltd1,355
2United States of America1,3542Toyota Motor Co1,145
3PCT7973Toyota Jidosha Kabushiki Kaisha624
4European Patent Office6794SANYO ELECTRIC CO LTD619
5China6435Matsushita Electric Ind Co Ltd575
6Canada1506Panasonic Co477
7Republic of Korea1107Nissan Motor Co Ltd476
8Australia978Mitsubishi Heavy Ind Ltd469
9India599Toshiba Co362
10United Kingdom3810Hitachi Ltd342
11Germany2111Tokyo Gas Co Ltd241
12Denmark1912Panasonic Ip Management Co234
13Spain1013Toyota Motor Co Ltd197
14Malaysia1014Panasonic Intellectual Property Management Co Ltd190
15South Africa915Toshiba Battery Co Ltd181
16France816Matsushita Electric Industrial Co Ltd145
17Indonesia617Toyota Central Res and Dev Lab Inc139
18Singapore618Toyota Industries Co136
19Mexico519Mitsubishi Heavy Industries Ltd135
20Philippines520Hitachi Maxell Ltd130

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b).

Graph 2

IPC code co-occurrence network (size and colour: weighted degree).

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b).

Table 3

Prominent IPC codes (subclass level).

IPC codeTitleDegreeWeighted degreeNumber of patents
H01MProcesses or means, e.g., batteries, for the direct conversion of chemical energy into electrical energy1696,7665,907
C01BNon-metallic elements; compounds thereof1454,4343,005
B60LPropulsion of electrically-propelled vehicles (…) 792,1211,276
C25BElectrolytic or electrophoretic processes for the production of compounds or non- metals; apparatus therefor1071,1421,239
B01JChemical or physical processes, e.g. catalysis or colloid chemistry; their relevant apparatus 982,1391,035
F17CVessels for containing or storing compressed, liquefied, or solidified gases (…)921,257784
B60KArrangement or mounting of propulsion units or of transmissions in vehicles (…) 671,500745
C22CAlloys 371,091725
B01DSeparation 951,217600
C10JProduction of gases containing carbon monoxide and hydrogen from solid carbonaceous materials (…)50545364
C08LCompositions of macromolecular compounds 47584332
B22FWorking metallic powder; manufacture of articles from metallic powder (…) 26600320
C02FTreatment of water, waste water, sewage, or sludge 58441257
F02CGas-turbine plants; air intakes for jet-propulsion plants; controlling fuel supply in air-breathing jet-propulsion plants 50509232
H02JCircuit arrangements or systems for supplying or distributing electric power; systems for storing electric energy 39329218
C07CAcyclic or carbocyclic compounds 43410201
F01KSteam engine plants; steam accumulators; engine plants not otherwise provided for; engines using special working fluids or cycles 49480187
F02MSupplying combustion engines in general with combustible mixtures or constituents thereof 44375171
B62DMotor vehicles; trailers 22363156
C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients 33309136

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b, 2024a).

Table 4

Prominent connections between IPC codes.

Source IPC codeTarget IPC codeNumber of patentsSource IPC codeTarget IPC codeNumber of patentsSource IPC codeTarget IPC codeNumber of patents
C01BH01M1,675B22FH01M248F01KF02C130
B60LH01M1,093C01BC25B229C10JF02C116
B01JC01B735C01BF17C226C01BC22C108
C22CH01M555B01DB01J188B01JC25B100
B60KH01M530B22FC22C183B60KF17C96
B60KB60L405B60KB62D142B62DH01M91
B01JH01M367H01MH02J141C10JF01K79
F17CH01M367B01DC02F137C01BF02M77
C25BH01M275C08KC08L132B60LB62D70
B01DC01B251B01DH01M130C08JC08L69

Source: Own interpretation based on PATENTSCOPE (WIPO, 2024b).

Table 5

Examples of hydrogen technology-related projects in Japan.

CompanyProject/partnersKey hydrogen technology
Kawasaki Heavy IndustriesHySTRA; HESCDeveloped the Suiso Frontier, the world’s first liquefied-hydrogen carrier (2019), and a liquefied-hydrogen receiving terminal (2020). Supplied a hydrogen power plant for Seibu Oil’s Yamaguchi Refinery, operational since August 2021.
Nippon Hydrogen Energy (Kawasaki Heavy Industries subsidiary)NEDO hydrogen supply-chain commercialization project with ENEOS and IwataniDevelopment of large-scale liquefied-hydrogen supply-chain infrastructure, including carriers, liquefiers, and storage tanks.
Electric Power Development Co. (J-POWER)Japan–Australia HESC demonstration projectCoal-gasification and lignite-derived hydrogen production. A demonstration plant near an Australian lignite mine began producing hydrogen in February 2021.
Chiyoda CorporationAHEAD consortium with Mitsubishi Corporation, Mitsui & Co., and Nippon Yusen Kabushiki KaishaSPERA Hydrogen®, an organic chemical hydride technology for hydrogen storage and transport.
Iwatani CorporationHySTRA, HESC, and Fukushima Hydrogen Energy Research Field (FH2R)Liquefied-hydrogen production and commercial hydrogen-refuelling stations.
Toshiba Energy Systems & SolutionsFH2R with NEDO, Tohoku Electric Power, and IwataniRenewable-powered, 10 MW-class hydrogen production system, among the world’s largest at the time of commissioning.
Woven Planet HoldingsWoven City project backed by Toyota, ENEOS, and Akio ToyodaHydrogen infrastructure for Woven City, including electrolysers at refuelling stations and stationary fuel-cell generators.

Source: Compiled from company reports and industry publications.

Table 6

SWOT analysis of Japan’s hydrogen economy, including findings from patent analysis.

Japan
StrengthsWeaknesses

  • Technological specialization in FCEVs and electrochemical technologies (strong co-occurrence between H01M and B60L).

  • Strong industrial base – hydrogen production, storage, catalysts, turbines, materials, and infrastructure (C01B, B01J, F17C, C25B, F02C).

  • Strong links such as C01B–H01M, B60L–H01M, and B01J–C01B mean that Japanese firms are good at combining chemistry, materials, electrochemical systems, and vehicle applications.

  • Competitive in high-value hydrogen systems.

  • Global leadership in hydrogen patents among incumbent firms.

  • • Strong technological coherence reflected in dense patent co-occurrence networks.

  • Heavy concentration around fuel-cell mobility may create technological lock-in.

  • C25B, associated with electrolysis, is connected to a wider range of technologies but with weaker overall ties than B60L. This suggests that electrolyzer innovation is more exploratory and less deeply integrated than fuel-cell mobility.

  • Declining patenting activity since 2016 suggests possible maturation of dominant technological pathways.

  • Strong domestic orientation suggests that Japan’s hydrogen economy depends heavily on national policy, infrastructure, standards, subsidies, and demand creation.

  • Japanese car manufacturers’ supply chains are traditionally complex and deeply entrenched, which limits quick adaptation.

OpportunitiesThreats

  • Export of fuel-cell technologies and hydrogen mobility solutions.

  • Leadership in maritime, heavy-duty transport, and hydrogen carriers.

  • Growing demand for hydrogen infrastructure and storage technologies globally.

  • Strategic partnerships with Australia, the Middle East, and Southeast Asia for hydrogen imports.

  • Potential expansion into hydrogen turbines and industrial applications.

  • Hydrogen as a renewal strategy for mature manufacturing sectors.

  • Rapid Chinese advances in electrolyzers and fuel cells may erode technological leadership.

  • Rising competition from EU and Chinese green hydrogen technologies.

  • Battery electric vehicles may reduce future demand for fuel-cell passenger vehicles.

  • Risk that hydrogen demand outside Japan develops more slowly than expected.

  • Dependence on imported hydrogen creates geopolitical vulnerabilities.

Source: Authors’ own elaboration.

DOI: https://doi.org/10.2478/ijme-2026-0007 | Journal eISSN: 2543-5361 (formerly 2299-9701) | Journal ISSN: 2299-9701
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Language: English
Page range: 62 - 74
Submitted on: Jul 1, 2026
Accepted on: Jul 6, 2026
Published on: Jul 24, 2026
Published by: SGH Warsaw School of Economics
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
Energy transition,
Hydrogen,
Japan,
Patent network analysis,
Technological innovation
JEL:
C4,
D85,
F23,
O3,
O53
Related subjects:
Business and economics,
Business management,
Management accounting, financial controlling, cost calculation, investment

© 2026 Anna Maria Dzienis, Artur F. Tomeczek, published by SGH Warsaw School of Economics
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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