Patent Intelligence | Global Patent Monitoring Report in the Fuel Cell Field (April 2020)

Introduction

Hello, readers! The monthly global patent monitoring report in the fuel cell field is here again. This monitoring report mainly includes three parts: an overall introduction to the public patents in the fuel cell field in April 2020; an introduction to the public patents of domestic applicants; an introduction to some applicants and their public patent interpretations, including Toyota's patent interpretation of ensuring impurity discharge during refresh control and operation optimization when the power required by the fuel cell system load decreases; Audi's patent interpretation of preventing the direct reaction of residual hydrogen and oxygen from causing catalyst degradation when the stack is shut down and restarted; Tsinghua University's fuel cell voltage control patent interpretation; Tongji University's fuel cell low-temperature start-up control patent interpretation, etc.

1. Overview

1.1 Geographical situation of patent disclosure

In April 2020, there were 1,106 patents published/authorized worldwide in the field of fuel cells, which is a certain increase compared with the previous month. This month, the number of invention patent applications published in China increased significantly compared with the previous month (166), the number of invention patent authorization announcements remained the same as the previous month, and the number of utility model patent authorization announcements increased slightly compared with the previous month. Some of the published countries/regions/organizations and the number are shown in Figure 1-1.

Figure 1-1 Fuel cell patent disclosure/authorization in some regions in April

1.2 Patent technology branches

Figure 1-2 Technology distribution of fuel cell patents published/authorized in April

1.3 Patent application status of applicants

After the patent applicants are standardized, the number of patent applications of standardized applicants is counted, as shown in Figures 1-3. This month, Toyota has published 80 patents, of which 46 are invention applications and 33 are invention authorizations; Honda and Nissan have published 33 and 31 patents respectively; Bosch and Weichai Power have published 21 patents this month, of which Bosch's patented technologies mainly involve battery stacks (catalysts, seals), hydrogen systems, and power systems, and Weichai Power's patented technologies mainly involve air systems, system control, thermal management, etc.; Gree Group has published 10 patents this month, and its patented technologies mainly involve battery stacks, humidification, etc., of which the battery stack is mainly based on bipolar plate-related technologies.

Figure 1-3 Ranking of published/authorized patents of standardization applicants in April

In terms of fuel cell inspection and testing, the companies that have disclosed patents related to fuel cell air tightness testing this month include China FAW, Fengyuan Hydrogen Energy , Shanghai Electric, Shenzhen Shichun, etc.; the companies that have disclosed patents related to fuel cell hydrogen system testing include Shanghai Shunhua New Energy, China Automotive Research Institute Automotive Inspection Center, Foshan Qingji, etc.; the companies that have disclosed patents related to fuel cell failure, defect, and life detection include Weichai Power, Shenzhen Shichun, and Beijing Aerospace Intelligent Manufacturing.

II. Patent Publication of Domestic Applicants

2.1 Patent disclosures of domestic OEMs in April

The patent disclosure of domestic vehicle manufacturers in April is shown in Figure 2-1. Among them, China FAW disclosed 22 patents, mainly involving bipolar plates, gas diffusion layers, air systems, detection and inspection, etc.; Grove disclosed 6 patents, mainly involving thermal management, automotive deionizers, etc.; Dongfeng Motor disclosed 5 related patents this month, mainly involving fuel cell vehicle cooling system control, energy management, oxygen supply, etc. Other vehicle manufacturers that disclosed related patents in April include SAIC Volkswagen, Yutong Bus, BAIC Group, Great Wall Motors, Feichi Automobile, Geely Automobile, GAC Group, Chery Automobile, King Long Bus, etc.

Figure 2-1 Patent disclosures by vehicle manufacturers in April

2.2 Patent disclosures of fuel cell companies in April

The patent disclosure of domestic fuel cell companies in April is shown in Figure 2-2. Among them, Shanghai Shenli disclosed 8 patents, mainly involving low-temperature startup, shutdown methods and activation technologies; China Huaneng Group Clean Energy Technology Research Institute Co., Ltd. disclosed 6 patents, mainly involving molten carbonate fuel cell related technologies; other companies that disclosed related patents in April include Henan Yuhydrogen, Zhejiang Gaocheng Green Energy, Shunhua New Energy, Xinyuan Power, Xiongtao Hydrogen, Wuhan Zhongji Hydrogen Energy, etc.

Figure 2-2 Patent disclosures of fuel cell companies in April

2.3 Patent disclosures of scientific research institutes (universities) in April

The patent disclosure of fuel cell related research institutes (schools) in April is shown in Figure 2-3. Among them, Dalian Institute of Chemical Physics of Chinese Academy of Sciences disclosed 13 patents, and its technology mainly involves the preparation of membrane electrode related components, bipolar plates, humidifiers, etc.; Tsinghua University disclosed 12 patents, and its technology mainly involves fuel cell status detection, system control, etc.; Foshan University of Science and Technology disclosed 5 patents this month, mainly involving catalytic electrode preparation; other research institutes (schools) that disclosed related patents in April include: Wuhan Marine Electric Propulsion Device Research Institute, Tongji University, Dalian University of Technology, University of Electronic Science and Technology of China, Shenzhen University, Wuhan University of Technology, etc.

Figure 2-3 Patent disclosure of fuel cell research institutes (schools) in April

III. Introduction to some applicants and published patents

Section 3 of this month will interpret the public patents of some applicants and briefly introduce the patent technology branches of some of the applicants involved.

3.1 Toyota

Figure 3-1 Toyota's patent technology branches in April

In April 2020, Toyota disclosed a total of 80 patents in the field of fuel cells , mainly involving technical branches such as fuel cell stacks, system control, hydrogen storage, and complete vehicles.

The patent publication numbers of Toyota's fuel cell system control related patents analyzed below are US20200136157A1 and JP2020057460A. Among them, US20200136157A1 involves the problem of impurity emissions during the execution of refresh control, and JP2020057460A involves the optimization of operation when the power required by the fuel cell system load becomes smaller.

3.1.1 US20200136157A1 - Ensuring impurity removal during refresh control

In a fuel cell system, the platinum catalyst will oxidize over time, and the oxide film and other impurities will adhere to the surface of the catalyst, thereby reducing the catalytic performance. In order to restore the catalyst performance, the fuel cell system will restore the power generation performance of the fuel cell by reducing the cell voltage of the fuel cell for a short time to reduce the oxide film on the surface of the platinum catalyst and cause the impurities to fall off the catalyst surface. This control method is called "refresh control". During the refresh control period, the oxide film is converted into oxygen and discharged from the fuel cell together with the exhaust gas due to the reduction reaction, but the impurities fall off from the platinum catalyst in a solid form. If the impurities are not discharged in time after the refresh control, but remain in the fuel cell, then during normal power generation, the impurities may be re-deposited on the surface of the platinum catalyst and affect the power generation performance of the fuel cell. In order to ensure that the solid impurities can be discharged from the fuel cell in time during the refresh control, it is necessary to ensure the liquid water content inside the stack during the refresh period so that the impurities are discharged from the fuel cell along with the liquid water.

However, during the period when the fuel cell performs refresh control, in order to reduce the voltage of the fuel cell stack, the cathode air intake will be reduced, and the amount of water generated by the cathode will be reduced. At this time, the fuel cell cannot produce enough liquid water to discharge impurities. In order to increase the liquid water as much as possible to discharge impurities, Toyota designed a system as shown in Figure 3-2. The fuel cell system includes two sub-fuel cell systems. When the fuel cell subsystem 9a performs refresh control, the fuel cell subsystem 9b generates electricity normally. At this time, the liquid water generated by the cathode of the fuel cell 9a decreases, while the cathode of the fuel cell subsystem 9b will generate a large amount of water and be discharged with the cathode exhaust gas. Toyota uses a large amount of water in the cathode exhaust gas of the fuel cell subsystem 9b to humidify the air intake side of the fuel cell subsystem 9a, or directly mixes the cathode exhaust gas of the fuel cell subsystem 9b with the air on the intake side of the fuel cell subsystem 9a to increase the humidity of the air entering the fuel cell subsystem 9a, so that the amount of liquid water on the cathode side of the fuel cell subsystem 9a can be guaranteed, and impurities can be discharged as much as possible through liquid water. In addition, Toyota also proposed that the cooling effect of the fuel cell stack can be improved during refresh control, further reducing the internal temperature of the fuel cell stack to reduce the saturated vapor pressure and promote the condensation of cathode moisture inside the fuel cell stack.

Figure 3-2 US20200136157A1 fuel cell system