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

Introduction

Hello, dear readers. The monthly global patent monitoring report in the field of fuel cells is here again. This monitoring report mainly includes three parts:

An overall introduction to the public patents in the fuel cell field in March 2020; an introduction to the public patents of domestic applicants; an introduction to some applicants and interpretations of their public patents, including Toyota's patent interpretation on a method for ensuring hydrogen discharge and a separator with improved drainage performance, Hyundai's patent interpretation on membrane electrode water management, Daimler's patent interpretation on a humidifier, and the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences' bipolar plate sealing patent interpretation.

1. Overview

1.1 Geographical situation of patent disclosure

In March 2020, there were 912 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 has dropped significantly compared with the previous month (255), the number of invention patent announcements has increased compared with the previous month (37), and the number of utility model patent announcements has remained the same as 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 March

1.2 Patent technology branches

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

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. Among them, Toyota has 97 patents disclosed, of which 55 are invention applications and 41 are invention authorizations; Hyundai and LG have 28 and 24 patents disclosed, respectively; the State Energy Investment Group Co., Ltd. and Beijing Low Carbon Clean Energy Research Institute, as joint applicants, have 13 patents disclosed, all of which are invention patent applications, mainly involving technologies related to hydrogen refueling stations and SOFC power generation systems; Wuhan Taige has 13 patents disclosed, of which utility model patents account for a large proportion, totaling 9.

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

This month, in terms of fuel cell applications, Fengjiang Intelligent Technology Co., Ltd. disclosed three patents on hybrid tractors equipped with fuel cells; Wuhan Haiyi New Energy Technology Co., Ltd. disclosed one patent involving fuel cell agricultural tractors; Doosan Mobike Innovation Co., Ltd. disclosed three patents on fuel cell drones; Toyota Motor Corporation disclosed six patents on community hydrogen energy and fuel cell applications.

II. Patent Publication of Domestic Applicants

2.1 Patent disclosures of domestic OEMs in March

The patent disclosure of domestic vehicle manufacturers in March is shown in Figure 2-1. Among them, China FAW disclosed 10 patents, and the technologies mainly involved catalyst preparation, system control, power system, etc.; Dongfeng Motor disclosed 4 patents, and the technologies mainly involved membrane electrode preparation, stack fixation, system control, etc.; other vehicle manufacturers that disclosed relevant patents in March include Wuhan Tiger, Grove, GAC Group, Chery Automobile, SAIC Group, etc.

Figure 2-1 Patent disclosure by vehicle manufacturers in March

2.2 Fuel cell companies’ patent disclosures in March

The patent disclosure of domestic fuel cell companies in March is shown in Figure 2-2. Among them, Jiangsu Huahe Hydrogen Power disclosed 8 patents, mainly involving fuel cell related technologies; Dayang Electric disclosed 7 patents, mainly involving reaction gas supply and power system, etc., of which 3 patents were PCT patent disclosures; other companies that disclosed related patents in March include Shenzhen Guoqing, Weichai Power, Xinkelihua, Shanghai Ji Chong, Juna New Materials, etc.

Figure 2-2 Fuel cell companies’ patent disclosures in March

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

The patent disclosure of fuel cell related research institutes (universities) in March is shown in the figure below. Among them, three research institutions, Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences, and Wuhan Institute of Marine Electric Propulsion Devices (mainly related to graphite bipolar plate technology) disclosed 10, 10, and 5 patents respectively; the universities that disclosed relevant patents in March include: Xi'an Jiaotong University, Beijing University of Science and Technology, Tsinghua University, Tianjin University, etc.

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 the applicants involved.

3.1 Toyota

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

As of March 2020, Toyota has disclosed a total of 97 patents in the field of fuel cells, mainly involving technical branches such as fuel cell stacks, system control, and complete vehicles.

The patent publication numbers of Toyota's fuel cell-related patents analyzed below are JP2020047418A and JP2020047440A (JP2020047441A and JP2020047442A). JP2020047418A mainly involves a method for removing hydrogen from a fuel cell stack before shutdown inspection and maintenance; JP2020047440A (JP2020047441A and JP2020047442A) mainly involves a separator with improved drainage performance.

3.1.1 JP2020047418A - Method for ensuring hydrogen is discharged from a fuel cell system

In order to ensure long-term stable power generation of fuel cells, they need to be shut down and inspected regularly. When inspecting the fuel cell system, for safety reasons, the fuel cell needs to be discharged and the hydrogen in the system needs to be replaced with inert gas, including the hydrogen in the stack and the hydrogen in the anode gas supply unit.

In the prior art, after the fuel cell stops generating electricity and judges to enter the discharge process, the inert gas (nitrogen, argon, etc.) is first supplied to the stack, and then the stack voltage is detected to be lower than the predetermined value Va; when the stack voltage is ≤Va, the discharge is judged to be complete. However, when the fuel cell stops generating electricity, its stack voltage may also be lower than Va. At this time, the discharge process is very short and it is impossible to ensure that the hydrogen in the system is completely discharged.

Based on this, JP2020047418A proposes a method and a fuel cell system for ensuring that hydrogen is completely discharged during the discharge process, as follows:

Figure 3-2 JP2020047418A fuel cell system

The vehicle fuel cell system is shown in FIG3-2. The fuel cell system 100 includes a stack 10, a control device 20, an anode gas supply unit 50, a cathode gas supply unit 30, etc. When the fuel cell system stops generating electricity, the supply of the reaction gas stops, and the residual voltage value of the stack is close to zero. The maintenance personnel connect the inert gas tank 72 to the anode gas supply unit 50, and then start pre-maintenance pretreatment.

The pre-processing process is shown in Figure 3-3 (a). First, the control unit 21 controls the air compressor to supply air to the cathode of the fuel cell stack at a predetermined speed (optionally 200NL/min) to increase the voltage of the fuel cell stack; the control unit determines whether the voltage value obtained from the voltage measurement unit 84 has risen to the preset voltage V1 (V1≈open circuit voltage OCV); if it has risen to V1, it further determines after a certain period of time whether the voltage value obtained by the voltage measurement unit 84 is less than or equal to the preset voltage V2 (V2 refers to the voltage value obtained through experiments or simulations when there is no hydrogen near the anode of the fuel cell, V2＜v1); when the voltage value ≤v2 , it means that the hydrogen at the anode is consumed; the control unit 21 then controls the anode gas supply unit 50 to supply inert gas to the stack, and the hydrogen in the anode pipe 51 is also supplied to the stack; the hydrogen supplied to the stack reacts with the cathode gas to increase the stack voltage again, and the voltage value is measured again to determine whether it has risen to v1; when the stack voltage rises to v1, after a certain period of time, the stack voltage is measured again to see if it has dropped to v3 (v3 can be set to ≤v2); when the stack voltage is ≤v3, it means that the hydrogen in the anode gas supply unit and the stack has been removed. ＜ p＝＂＂＞

Figure 3-3 (a) Pretreatment flow chart; (b) Voltage changes during pretreatment

After the pretreatment is completed, maintenance personnel can inspect, maintain, and repair the fuel cell system.

3.1.2 JP2020047440A (JP2020047441A, JP2020047442A) - A partition for improving drainage performance

Figure 3-4 Schematic diagram of the existing partition structure

One side of the fuel cell separator is formed with gas flow paths 4A and 4B for the reaction gas to flow through. When the water generated by power generation remains in the gas flow paths, the diffusivity of the reaction gas may be reduced, causing the power generation performance of the fuel cell to decline. To this end, the prior art provides a plurality of fine grooves 6 on the groove wall surface of the gas flow path, and the fine grooves are in contact with the gas diffusion layer, so that the liquid water can be quickly separated from the gas diffusion layer and flow along the fine grooves to be discharged.

In order to further optimize the power generation performance of fuel cells, JP2020047440A (JP2020047441A, JP2020047442A) proposed to improve the design of the drainage groove, as follows: