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Hydrogen production by water electrolysis. Patent landscape

Sourse: EnvatoElements

Aenert news. Invention analysis
Electrolysis is one of the main technologies for producing green hydrogen. However, to date, hopes for achieving acceptable competitiveness of this technology compared, for example, with steam reforming, have not been justified. The cost of hydrogen produced by electrolysis remains too high for mass production. In addition, another important problem for electrolysis is the high water requirements and its high consumption. Also, if we are talking exclusively about green hydrogen throughout the production chain, the inevitable requirement remains the use of electricity from renewable sources or at least from nuclear plants. This predetermines the formation of additional and inconvenient questions regarding the logistics of the process, since moving hydrogen production centers closer to hydroelectric power stations or wind farms almost always means moving them away from the centers of its consumption.
Obviously, the only possible option for the required increase in the technical and economic indicators of electrolysis is the accumulation of a “critical mass” of useful engineering solutions. A significant part of new innovative proposals in the field of electrolysis technology is concentrated in patented inventions. Below is an assessment of patents related to Hydrogen production by water electrolysis over the past 20 years. In the first stage, a preliminary body of patent documents was selected from publicly available databases using traditional methods, including the use of keywords, international patent classification indicators, names of principal applicants, lists of related patents, etc. At the second stage, each of the pre-selected patent documents was further analyzed for its compliance with the specified criteria for the text of the invention. Thus, a compact patent database was formed that was most relevant to technical solutions in the field of electrolysis for the period from 2002 to 2023. Statistics are provided for a twenty-year period up to 2022. Data for 2023 are excluded from the statistical analysis due to the incompleteness of their full processing, but individual inventions over the past year were used when accounting for patent families and analyzing original technical solutions. A total of 3,023 patents were found, of which 2,617 relate to the period 2003-2022.

Breakdown of documents by publication date

Inventor productivity has especially increased over the past three years, with the number of new patent applications exceeding a thousand documents annually.

The largest number of patents during the period under review was issued by the Chinese patent office. At the same time, the share of Chinese patents has been continuously growing over the past ten years. In 2022, this share was 62%. The top five largest patent offices in terms of the number of issued patents also included the Japanese, American, European and South Korean patent offices.

Breakdown of documents by patent offices. Patents, 2003-2022

Chinese applicants also led the way in the number of patents received. However, in this case the gap from its closest competitors was significantly smaller. Applicants followed Chinese inventors from Japan, France, USA, South Korea and Germany.

Among the patent documents, various methods prevailed, then compositions and, finally, devices. The technological categories in this study include the main technological options for water electrolysis, including Alkaline water electrolysis, Solid oxide electrolysis; Polymer electrolyte membrane electrolysis, Anion Exchange Membrane Electrolysis, as well as a combination of all other options (Other electrolysis). A separate group also includes inventions whose claims describe in detail the design, materials or operating principle of the electrolyzer itself, which uses electricity from renewable sources (Renewable energy-based electrolysis). If the text of a patent document describes a method for generating electricity and only mentions that such energy can be used for electrolysis of water, but does not describe the electrolysis process in detail, such documents were excluded from consideration.

Patents, 2003-2022 (by the number of mentions in patent documents)

AEL- Alkaline water electrolysis; SOEL - Solid oxide electrolysis; PEME - Polymer electrolyte membrane electrolysis; AEME - Anion Exchange Membrane Electrolysis;  RENE - Renewable energy-based electrolysis; OEL - Other electrolysis

As follows from the above diagram, the greatest interest among inventors was shown in Other electrolysis, Alkaline water electrolysis and Polymer electrolyte membrane electrolysis. A little over a hundred patents are assigned to the Renewable energy-based electrolysis group.

Technological elements are represented by a set of basic structural objects of electrolyzers (anodes, cathodes, separators, electrolyzers and systems as a whole), as well as catalysts and electrolytes. This also includes some technological operations, such as High-Temperature Steam Electrolysis, High-pressure electrolysis, Water/steam conditioning, Control & monitoring, Stacking and scaling, Hydrogen conditioning.

Patents, 2003-2022 (by the number of mentions in patent documents)

HTSE - High-Temperature Steam Electrolysis; HPE - High-pressure electrolysis; WSC - Water/steam conditioning; Els - Electrolyser; And - Anode; Cat - Cathode; Sep - Separator; Elct - Electrolyte; Ctls - Catalyst; Ctrl - Control & monitoring; Scl - Stacking and scaling; H2C - Hydrogen conditioning; SAW -System as a whole

The undisputed leader in this option were catalysts. Also popular were the designs of anodes, cathodes, and the design of electrolyzers in general.

Breakdown of documents by problems. Patents, 2003-2022 (by the number of mentions in patent documents)

LEMP - Low efficiency / Main process, LESP - Low efficiency / Secondary process, LEG - Low efficiency in general, HCPC - High CAPEX / Plant construction, HCEP - High CAPEX / Equipment production, HORR - High OPEX / Repair & replacement, HOOC - High OPEX / Operation & consumables, HCM - High cost of materials, HCG - High cost in general, ESI - Environmental and Safety issues, UP - Unclear problem

The share of the problems noted in the texts of the inventions is shown in the diagram above. Among them, Low efficiency / Main process and High cost of materials had the greatest weight.

List of IPC subgroups. Patents, 2003-2022 (by the number of mentions in patent documents)


IPCShareIPCs assigned

In patent documents, inventors most often mentioned the international patent classification index - C25B1/04 - Electrolytic production of inorganic compounds or non-metals by electrolysis of water.

To conclude this brief review, we provide a list of top applicants who have patented at least 20 inventions.

Top applicants. Patents, 2003-2022


ApplicantAverage ratingTotal
Commissariat à l'énergie atomique et aux énergies alternatives (FR)16.8243
Honda Motor Co., Ltd. (JP)15.6172
De Nora Permelec Ltd (JP)16.988
Asahi Kasei Kogyo K.K. (JP)16.751
Sumitomo Electric Industries, Ltd. (JP)14.340
CAS DICP Dalian Institute of Chemical Physics (CN)16.434
Kawasaki Heavy Industries, Ltd. (JP)17.333
McAlister Technologies, LLC (US)15.730
Shaanxi University of Science and Technology (CN)15.230
Asahi Kasei Corporation (JP)16.428
SCUT South China University of Technology (CN)1326
Korea Institute of Science and Technology (KIST) (KR)1524
Anhui Normal University (CN)12.823
THU Tsinghua University (CN)15.623
Jiangsu University (CN)13.221
Toshiba Corporation (JP)14.121
Toshiba KK (JP)13.421
Panasonic Intellectual Property Management Co. Ltd. (JP)13.920

By the Editorial Board