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KR-102964573-B1 - Thermal management system of open cathode fuel cell stack using short circuit

KR102964573B1KR 102964573 B1KR102964573 B1KR 102964573B1KR-102964573-B1

Abstract

An open-cathode fuel cell stack thermal management system using a short circuit is disclosed. The open-cathode fuel cell stack thermal management system using a short circuit includes a fuel cell stack, a short circuit that generates heat by short-circuiting the anode and cathode of the fuel cell stack, a temperature sensor that measures the temperature of the fuel cell stack, and a controller that controls the ON/OFF of the short circuit according to the temperature of the fuel cell stack to heat the fuel cell stack during a cold start.

Inventors

  • 한재영
  • 현대일
  • 윤진원

Assignees

  • 국립공주대학교 산학협력단
  • 영산대학교산학협력단

Dates

Publication Date
20260513
Application Date
20230310

Claims (5)

  1. In an open cathode fuel cell stack thermal management system using a short circuit, Fuel cell stack; A short circuit that generates heat by short-circuiting the anode and cathode of the above fuel cell stack; An air supply fan that supplies air to the fuel cell stack by blowing air into the cathode of the fuel cell stack to cool the fuel cell stack and supply oxygen to the fuel cell stack; A heater for heating the air supplied to the above fuel cell stack; A first temperature sensor for measuring the temperature of the fuel cell stack; A second temperature sensor for measuring the ambient temperature of the above-mentioned open cathode fuel cell stack thermal management system; A controller that controls the ON/OFF of the short circuit and the heater according to the temperature of the fuel cell stack in order to heat the fuel cell stack during a cold start of the fuel cell stack; An auxiliary battery that supplies power to the above heater; A battery sensor for measuring the charge amount of the above auxiliary battery; A first power converter connected between the auxiliary battery and the heater to control the power supplied from the auxiliary battery to the heater; A second power converter connected between the fuel cell stack and the load to control the power supplied from the fuel cell stack to the load; and It includes a bidirectional power converter connected between the auxiliary battery and the second power converter to control the power flow between the auxiliary battery and the fuel cell stack, The above-mentioned bidirectional power converter is equipped with a charging function and charges the auxiliary battery using power generated by the above-mentioned fuel cell stack, and The above controller is, When the temperature of the fuel cell stack is below the ambient temperature, when the temperature of the fuel cell stack is below a preset reference temperature and the charge amount exceeds a preset reference charge amount, both the heater and the short circuit are turned on. When the temperature of the fuel cell stack is below the ambient temperature, when the temperature of the fuel cell stack is below a preset reference temperature and the charge amount is below a preset reference charge amount, the heater is turned off and the short circuit is turned on. When the temperature of the fuel cell stack exceeds the ambient temperature, when the temperature of the fuel cell stack is below a preset reference temperature and the charge amount exceeds a preset reference charge amount, the heater is turned on and the short circuit is turned off. An open cathode fuel cell stack thermal management system using a short circuit, characterized in that when the temperature of the fuel cell stack exceeds the ambient temperature, the temperature of the fuel cell stack is below a preset reference temperature and the charge amount is below a preset reference charge amount, the heater is turned off and the short circuit is turned on.
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Description

Thermal management system of open cathode fuel cell stack using short circuit The present invention relates to an open cathode fuel cell stack thermal management system using a short circuit. Conventional fuel cells have hydrogen and oxygen supply lines configured as a closed loop, and perform cooling using cooling water lines to maintain an efficient temperature range. On the other hand, open-cathode air-cooled fuel cells have the oxygen supply electrode exposed to the atmosphere and use a fan to blow air in to supply oxygen while simultaneously performing air cooling. Since the output of such air-cooled fuel cells can vary depending on atmospheric conditions, this can adversely affect the stability of application systems, such as drones and UAMs. Therefore, measures must be devised to maintain the optimal operating temperature of the fuel cell, taking into account load operating conditions. In particular, air-cooled fuel cells require a solution to the problems that occur in sub-zero temperature environments during winter. Figure 1 is a diagram showing the cathode structure of an open cathode fuel cell. Referring to Figure 1, the open cathode fuel cell has a structure in which oxygen must be supplied to the cathode, water freezes under sub-zero temperature conditions, and there is a possibility of reduced efficiency and inability to operate due to the low operating temperature. In other words, in sub-zero winter temperatures, the water passing through the fuel cell membrane may freeze, making initial starting impossible or causing a decrease in output due to low-temperature operation; therefore, a flow of ambient temperature water is required during initial cold starts. Additionally, forced heating is necessary under environmental conditions where the amount of heat dissipated to the outside is greater than the amount of heat generated by the electrochemical reaction inside the fuel cell. Figure 1 is a diagram showing the cathode structure of an open cathode fuel cell. FIG. 2 is a diagram schematically illustrating the configuration of an open cathode fuel cell stack thermal management system using a short circuit according to an embodiment of the present invention. FIG. 3 is a diagram schematically illustrating the configuration of an open cathode fuel cell stack thermal management system using a short circuit according to another embodiment of the present invention. As used in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "composed" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be excluded, or that additional components or steps may be included. Furthermore, terms such as "...part," "module," etc., as used in the specification refer to a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software. Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. 2 is a diagram schematically illustrating the configuration of an open cathode fuel cell stack thermal management system using a short circuit according to an embodiment of the present invention. Hereinafter, with reference to FIG. 2, an open cathode fuel cell stack thermal management system using a short circuit according to an embodiment of the present invention will be described. Referring to FIG. 2, an open cathode fuel cell stack thermal management system using a short circuit according to an embodiment of the present invention may be configured to include a fuel cell stack (10), a short circuit (60), a second power converter (70), a temperature sensor (90), and a controller (120). The fuel cell stack (10) is a tertiary battery that generates power by chemically reacting a fuel substance (e.g., hydrogen) using a catalyst, and is formed as an open cathode type to perform air cooling and receive oxygen supply. That is, the fuel cell stack (10) may be configured to include an electrolyte (11), a catalyst layer (12) stacked on both sides of the electrolyte (11), a gas diffusion layer (13) stacked on both sides of the catalyst layer (12) and receiving a reaction gas (hydrogen and oxygen) to diffuse into the catalyst layer (12), and an anode separator (14) and a cathode separator (15) stacked on both sides of the gas diffusion layer (13). Here, the anode separator (14) may be formed in a closed shape, and the cathode separator (15) may be formed in an open shape. The short circuit (60) shorts the anode and cathode of the fuel cell stack (10) to generate heat. That is, the short circuit (60) utilizes the principle that when the positive electrode connected to the load in an electrical circuit is short-circuited, a large curr