System and method for controlling cold start of a fuel cell

Abstract

The present invention relates to a system and a method for controlling a cold start of a fuel cell. The system includes a fuel cell configured to be supplied with a fuel gas and an oxidizing gas to generate electric power; a main bus bar configured to electrically connect an output terminal of the fuel cell to a high voltage battery, an auxiliary device, or a drive device to output the electric power generated by the fuel cell; a main relay provided at the main bus bar between the output terminal of the fuel cell and the high voltage battery, the auxiliary device, or the drive device, and configured to electrically turn on or off the main bus bar; a COD resistor connected to the main bus bar on the output terminal side of the fuel cell based on the main relay; and a controller configured to supply the electric power generated by the fuel cell to the COD resistor in a state in which the main relay is turned off, and to control the COD resistor to consume the electric power generated by the fuel cell and supplied to the COD resistor.

Description

Technical Field

[0001] This invention relates to a technique for rapidly increasing the temperature of a fuel cell during cold start-up. Background Technology

[0002] A fuel cell is a battery that directly converts the chemical energy produced by the oxidation of fuel into electrical energy; it is a type of power generation device. Fundamentally, fuel cells are similar to chemical batteries in that they utilize oxidation and reduction reactions. However, unlike chemical batteries, which operate within a closed system, fuel cells continuously supply reactants from the outside and continuously remove reaction products from the system. Recently, fuel cell power generation systems have been put into practical use. Because the reaction product of fuel cells is pure water, research is actively underway to use fuel cell power generation systems as an energy source for environmentally friendly vehicles.

[0003] The fuel cell system includes a fuel cell stack, an air supply unit, and a hydrogen supply unit. The fuel cell stack is configured to generate electricity through a chemical reaction; the air supply unit is configured to supply air to the air electrode of the fuel cell stack; and the hydrogen supply unit is configured to supply hydrogen to the hydrogen electrode of the fuel cell stack. That is, oxygen-containing air is supplied to the air electrode (cathode) of the fuel cell stack, and hydrogen is supplied to the hydrogen electrode (anode) of the fuel cell stack.

[0004] When starting a fuel cell in a cooled state, a cold start strategy is used, in which the fuel cell generates its own heat and enables the load unit to operate. Typically, the load unit that heats the fuel cell in a fuel cell vehicle includes the fuel cell vehicle's auxiliary equipment, the high-voltage battery, and the resistor (cathode oxygen depletion (COD) resistor).

[0005] Specifically, in the cold start control of the fuel cell, the main relay connected to the main bus terminal of the fuel cell is turned on to charge the high-voltage battery while driving auxiliary devices including an air compressor, and at the same time consumes power from the resistor.

[0006] During the cold start control of the fuel cell, electricity is consumed by driving an air compressor. Problems such as reduced durability due to excessive air being pressurized into the fuel cell stack and excessive noise generation due to driving the air compressor may occur.

[0007] It should be understood that the above description of the background technology is only for the purpose of facilitating the understanding of the background of the present invention, and should not be regarded as an admission that the background technology is known to those skilled in the art. Summary of the Invention

[0008] This invention provides a cold start control technology to prevent air pressurization during cold start control of a fuel cell, while ensuring the maximum load available for heating the fuel cell.

[0009] To achieve the above objectives, a system for controlling the cold start of a fuel cell according to the present invention comprises: a fuel cell configured to be supplied with fuel gas and oxidizing gas to generate electricity; a main bus terminal configured to electrically connect the output of the fuel cell to a high-voltage battery, an auxiliary device, or a drive device to output the electricity generated by the fuel cell; a main relay disposed at the main bus terminal between the output of the fuel cell and the high-voltage battery, the auxiliary device, or the drive device, and the main relay being configured to electrically connect or disconnect the main bus terminal; a COD resistor connected to the main bus terminal at the output of the fuel cell based on the main relay; and a controller configured to supply the electricity generated by the fuel cell to the COD resistor when the main relay is disconnected, and to control the COD resistor to consume the electricity generated by the fuel cell and supplied to the COD resistor.

[0010] The COD resistor can be configured to actively control power consumption through switching control, and the controller can be configured to control the COD resistor so that the output voltage of the fuel cell is kept below a preset voltage.

[0011] The controller can be configured to supply power to auxiliary devices or drive devices by discharging a high-voltage battery.

[0012] The system may further include a monitoring unit configured to monitor the charge level of the high-voltage battery or the power it can output. The controller may be configured to perform a control operation such that when the charge level of the high-voltage battery monitored by the monitoring unit is equal to or less than a preset charge level, or when the power it can output is equal to or less than a preset power level, the main relay is activated.

[0013] The controller can be configured to perform a control operation such that when the output voltage of the fuel cell is equal to or greater than a preset voltage, the main relay is turned on, thereby supplying the power generated by the fuel cell to the high-voltage battery, auxiliary device, or drive device.

[0014] The controller can be configured to perform a control operation such that when the power generated by the fuel cell is equal to or greater than the maximum power consumption of the COD resistor, the main relay is turned on.

[0015] The controller can be configured to perform a control operation such that when the time consumed to supply power generated by the fuel cell to the COD resistor in the state of main relay being off is equal to or longer than a preset time, the main relay is turned on based on the sum of the calorific value of the fuel cell and the calorific value of the COD resistor.

[0016] The system may further include a determining unit configured to determine cold-start conditions based on the temperature of the coolant circulating to cool the fuel cell or the temperature of the air supplied to or exhausted from the fuel cell. The controller may be configured to supply power generated by the fuel cell to the COD resistor while the main relay is off, when the determining unit determines that the cold-start conditions are met.

[0017] The controller can be configured to supply power generated by the fuel cell to the COD resistor, high-voltage battery, auxiliary device, or drive device when the determining unit determines that the cold start conditions are met and the main relay is turned on when the temperature of the coolant or the temperature of the air is equal to or higher than a preset temperature.

[0018] The method for controlling the cold start of a fuel cell according to the present invention to achieve the above objectives may include: supplying power generated by the fuel cell while the main relay at the main bus terminal is off, wherein the main bus terminal electrically connects the output terminal of the fuel cell to a high-voltage battery, an auxiliary device, or a drive device; and controlling a COD resistor to consume the power generated by the fuel cell.

[0019] The COD resistor can be configured to actively control power consumption through switching control, and in the step of controlling the COD resistor, the COD resistor can be controlled to keep the output voltage of the fuel cell below a preset voltage.

[0020] The method may further include, after the step of supplying power to the COD resistor, the following step: discharging the high-voltage battery to supply power to the auxiliary device or drive device.

[0021] The method may further include the following steps: monitoring the charge or output power of the high-voltage battery before supplying power to the auxiliary device or drive device; and executing control such that when the monitored charge of the high-voltage battery is equal to or less than a preset charge or when the output power is equal to or less than a preset power, the main relay is turned on.

[0022] The method may further include the following steps after the step of controlling the COD resistor: by executing control such that when the output voltage of the fuel cell is equal to or greater than a preset voltage, the main relay is turned on, and the power generated by the fuel cell is supplied to the high-voltage battery, auxiliary device or drive device.

[0023] The method may further include the following step after the step of controlling the COD resistor: performing control such that the main relay is turned on when the total power generated by the fuel cell is equal to or greater than the maximum power consumption of the COD resistor, or when the sum of the calorific value of the fuel cell and the calorific value of the COD resistor is at its maximum.

[0024] The method may further include, prior to the step of supplying power to the COD resistor, the following step: determining cold-start conditions based on the temperature of the coolant circulating to cool the fuel cell or the temperature of the air supplied to or exhausted from the fuel cell. In the step of supplying power to the COD resistor, when the cold-start conditions are determined to be met, power generated by the fuel cell can be supplied to the COD resistor with the main relay off.

[0025] The method may further include the following steps after the step of determining the cold start conditions: in a state where the main relay is turned on when the cold start conditions are determined to be met and when the temperature of the coolant or the temperature of the air is equal to or higher than a preset temperature, the power generated by the fuel cell is supplied to the COD resistor and the high-voltage battery, auxiliary device or drive device.

[0026] The system and method for controlling the cold start of a fuel cell according to the present invention can rapidly increase the heat generation of the fuel cell during cold start.

[0027] In addition, it can solve the problems of reduced durability and noise caused by air pressurization of the air compressor. Attached Figure Description

[0028] The above and other aspects, features and advantages of the invention will become more apparent from the detailed description that follows in conjunction with the accompanying drawings, in which:

[0029] Figure 1 This is a block diagram illustrating the initial state of a cold start performed by a system for controlling the cold start of a fuel cell according to an embodiment of the present invention;

[0030] Figure 2 This is a block diagram illustrating the termination state of a cold start performed by a system for controlling the cold start of a fuel cell according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram illustrating the calorific value of a fuel cell in a system for controlling the cold start of a fuel cell according to an embodiment of the present invention is provided; and

[0032] Figure 4 This is a flowchart of a method for controlling the cold start of a fuel cell according to an embodiment of the present invention. Detailed Implementation

[0033] The specific structural or functional descriptions of the embodiments of the invention disclosed in this specification or application are for the purpose of describing embodiments according to the invention. Therefore, embodiments according to the invention can be implemented in various forms, and the invention should not be construed as limited to the embodiments described in this specification or application.

[0034] Various changes and modifications can be made to embodiments according to the invention, and therefore specific embodiments will be shown in the drawings and described in this specification or application. However, it should be understood that embodiments based on the concept of the invention are not limited to the particularly disclosed embodiments, and the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0035] Terms such as “first” and / or “second” may be used to describe various elements, but these elements should not be limited by these terms. These terms are intended only to distinguish one element from another. For example, without departing from the scope of this invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a second element.

[0036] When an element is described as being "connected to" or "accessing" other elements, it should be understood that not only is the element directly connected to or accessing other elements, but there may also be another element between them. Conversely, when a component is described as being "directly connected to" or "directly accessing" any other component, it should be understood that there is no component between them. Other expressions describing relationships between structural elements, namely "between" and "directly between," or "adjacent to" and "directly adjacent to," should be interpreted similarly to the above description.

[0037] The terminology used in this invention is for describing particular embodiments only and is not intended to limit the invention. Singular expressions may include plural expressions unless they are clearly different in the context. As used herein, the expressions “comprising” or “having” are intended to indicate the presence of the mentioned features, values, steps, operations, elements, components, or combinations thereof, and should be construed as not excluding the possibility of the presence or addition of one or more other features, values, steps, operations, elements, components, or combinations thereof.

[0038] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries may be interpreted as having the same meaning in the context of the relevant technical field, and should not be interpreted as having an idealized or overly formal meaning, unless expressly defined herein.

[0039] Exemplary embodiments of the invention will be described in detail below with reference to the accompanying drawings. The same or similar reference numerals presented in the drawings denote the same or similar elements.

[0040] Figure 1 This is a block diagram illustrating the initial state of a cold start performed by a system for controlling the cold start of a fuel cell 10 according to an embodiment of the present invention.

[0041] refer to Figure 1 According to an embodiment of the present invention, a system for controlling the cold start of a fuel cell 10 includes: a fuel cell 10, a main bus terminal 20, a main relay 30, and a cathode oxygen consumption (cathode oxygen) device. A depletion (COD) resistor 40 and a controller 50 are included. The fuel cell 10 is configured to be supplied with each of a fuel gas and an oxidizing gas to generate electricity. A main bus terminal 20 is configured to electrically connect the output of the fuel cell 10 to a high-voltage battery 60, auxiliary devices 21 and 22, or a drive unit (not shown) to output the electricity generated by the fuel cell 10. A main relay 30 is disposed at the main bus terminal 20 between the output of the fuel cell 10 and the high-voltage battery 60, auxiliary devices 21 and 22, or a drive unit (not shown), and is configured to electrically connect or disconnect the main bus terminal 20. A COD resistor 40 is connected to the main bus terminal 20 at the output of the fuel cell 10 based on the main relay 30. The controller 50 is configured to supply the electricity generated by the fuel cell 10 to the COD resistor 40 when the main relay 30 is disconnected, and to control the COD resistor 40 to consume the electricity generated by the fuel cell 10 and supplied to it.

[0042] The controller 50 according to an exemplary embodiment of the present invention may be implemented using a non-volatile memory (not shown) and a processor (not shown), the non-volatile memory being configured to store an algorithm (configured to control the operation of various components of the vehicle) or data relating to software instructions for reproducing the algorithm, and the processor being configured to perform the operations described below using the data stored in the respective memory. Here, the memory and processor may be implemented as separate chips. Alternatively, the memory and processor may be implemented as a single chip integrated with each other. The processor may take the form of one or more processors.

[0043] The fuel cell 10 generates electricity by receiving fuel gas on the anode side and oxidizing gas on the cathode side. The fuel cell 10 can be a fuel cell stack comprising multiple stacked cells. In an embodiment, the fuel gas is hydrogen, the oxidizing gas is oxygen, and oxygen-containing air can be supplied to the fuel cell 10.

[0044] The main bus terminal 20 can be electrically connected to the output terminal of the fuel cell 10 to transmit the power generated by the fuel cell 10. In particular, as will be described below, the main bus terminal 20 can be connected to the high-voltage battery 60, auxiliary devices 21 and 22, or a drive unit (not shown) to transmit the power generated by the fuel cell 10.

[0045] The high-voltage battery 60 can be charged by the electricity generated by the fuel cell 10, and conversely, the high-voltage battery 60 can supply power to auxiliary devices 21 and 22 or drive devices (not shown) connected to the main bus terminal 20 during discharge. In particular, the high-voltage battery 60 is connected to the main bus terminal 20 via a bidirectional high-voltage DC / DC converter (BHDC), and can be charged or discharged by voltage control of the bidirectional converter.

[0046] The main bus terminal 20 is equipped with a main relay 30 to electrically connect or disconnect the output terminal of the fuel cell 10 from the high-voltage battery 60, auxiliary devices 21 and 22, or a drive device (not shown). When the main bus terminal 20 is connected, the power generated by the fuel cell 10 can be transmitted to the high-voltage battery 60, auxiliary devices 21 and 22, or a drive device (not shown), and when the main bus terminal 20 is disconnected, the power generated by the fuel cell 10 will not be transmitted to the high-voltage battery 60, auxiliary devices 21 and 22, or a drive device (not shown).

[0047] COD resistor 40 can be connected to main bus terminal 20 at the output end of fuel cell 10 relative to main relay 30. That is, even when main relay 30 is off, COD resistor 40 can still be connected to the output end of fuel cell 10 via main bus terminal 20.

[0048] In related technologies, the COD resistor 40 is simply a resistor connected to opposite ends. However, according to an embodiment of the present invention, the COD resistor 40 can be a device capable of output control. That is, the COD resistor 40 can be a device capable of controlling power consumption, while also including a resistor that generates heat when consuming power received from the output of the fuel cell 10.

[0049] The controller 50 can supply power generated by the fuel cell 10 to the COD resistor 40 via the main bus terminal 20 when the main relay 30 is disconnected. Furthermore, the controller 50 can control the COD resistor 40 to consume power supplied from the fuel cell 10.

[0050] In the implementation scheme, the controller 50 can perform a control operation that causes the main relay 30 to be disconnected during cold start control, but normally, the main relay 30 can be in a disconnected state during the start-up of the fuel cell 10.

[0051] With the main relay 30 on, the output voltage of the fuel cell 10 should be maintained at a level equal to or higher than the minimum voltage subsequently used to drive the auxiliary devices 21 and 22 or the drive device (not shown). However, with the main relay 30 off, the fuel cell 10 generates electricity inefficiently at a voltage lower than the minimum voltage used to drive the auxiliary devices 21 and 22 or the drive device (not shown), thus increasing its own calorific value.

[0052] Therefore, according to the cold start control of the present invention, the calorific value of the fuel cell 10 is increased by controlling the power consumption of the COD resistor 40 when the main relay 30 is off.

[0053] More specifically, the COD resistor 40 can actively control power consumption through switching control, and the controller 50 can control the COD resistor 40 so that the output voltage of the fuel cell 10 is kept below a preset voltage.

[0054] In the implementation scheme, the controller 50 can control the COD resistor 40 so that the voltage at the output of the fuel cell 10 is maintained at a low voltage state (e.g., 150V) below a preset voltage.

[0055] In one embodiment, the COD resistor 40 may include an insulated-gate bipolar transistor (IGBT), and its power consumption can be controlled by switching. In another embodiment, under the control of the controller 50, the power consumption of the COD resistor 40 can vary from 10kW to 30kW.

[0056] In this way, by applying a COD heater that can actively output control, the output of the COD heater can be changed based on the output voltage of the fuel cell 10 and the power consumed by the COD heater during cold start, thereby maximizing the heating load.

[0057] In other words, by enabling variable output control of the COD heater, sufficient heating load can be ensured even without air pressurization, which is different from the cold start strategy in the prior art that requires the current consumed by the air compressor 21 as a heating load to pressurize the air during cold start.

[0058] The controller 50 can supply power to auxiliary devices 21 and 22 or a drive device (not shown) by discharging the high-voltage battery 60.

[0059] With the main relay 30 off, the controller 50 can supply power to the auxiliary devices 21 and 22 or the drive device (not shown) via the main bus terminal 20 by discharging the high-voltage battery 60. At the same time, the controller 50 can supply power generated by the fuel cell 10 to the COD resistor 40 via the main bus terminal 20.

[0060] In an implementation scheme, auxiliary devices 21 and 22 (BOP) may include an air compressor 21 (ACP), a cooling pump 22 (CSP), etc., wherein the air compressor 21 is configured to supply air to the fuel cell 10, and the cooling pump 22 is configured to circulate the coolant cooling the fuel cell 10.

[0061] The controller can use the power charged in the high-voltage battery 60 to drive auxiliary devices 21 and 22 or a drive device (not shown) when the high-voltage battery 60 is discharged before the main relay 30 is turned on. Thereafter, with the main relay 30 turned on, the controller can use the power generated by the fuel cell 10 to drive auxiliary devices 21 and 22 or a drive device (not shown).

[0062] Figure 2 This is a block diagram illustrating the termination state of a cold start of a fuel cell 10 performed by a system for controlling the cold start of a fuel cell 10 according to an embodiment of the present invention.

[0063] Further reference Figure 2 The system may further include a monitoring unit 61, which is configured to monitor the charge level or output power of the high-voltage battery 60. The controller 50 may perform a control operation such that when the charge level of the high-voltage battery monitored by the monitoring unit 61 is equal to or less than a preset charge level or the output power is equal to or less than a preset power level, the main relay 30 is activated.

[0064] In the implementation scheme, the monitoring unit 61 can be a battery management system (BMS) configured to: monitor the charge (state of charge, SOC) of the high-voltage battery 60 in real time, or monitor the output power of the high-voltage battery 60 depending on the charge of the high-voltage battery 60, the state of the bidirectional converter, etc.

[0065] When the power level of the high-voltage battery 60 monitored by the monitoring unit 61 is equal to or less than the preset power level, or when the power that can be output is equal to or less than the preset power level, the controller 50 can perform a control operation to turn on the main relay 30.

[0066] Here, a preset power or preset energy can be preset based on the power required by the auxiliary devices 21 and 22 or the drive device (not shown).

[0067] In situations where it is difficult to supply the required power to the auxiliary devices 21 and 22 or the drive unit (not shown) based on the charge or output power of the high-voltage battery 60, the controller 50 may perform a control operation to turn on the main relay 30, thereby supplying the power generated by the fuel cell 10 to the auxiliary devices 21 and 22 or the drive unit (not shown), or to charge the high-voltage battery 60.

[0068] In another embodiment, the controller 50 can perform a control operation such that when the output voltage of the fuel cell 10 is equal to or greater than a preset voltage, the main relay 30 is turned on, thereby supplying the power generated by the fuel cell 10 to the high-voltage battery 60, auxiliary devices 21 and 22, or a drive device (not shown).

[0069] That is, in the initial state of cold start of fuel cell 10, controller 50 can control the power generation of fuel cell 10 with main relay 30 off, and in the terminated state of cold start of fuel cell 10 performed by the system for controlling cold start, controller 50 can perform a control operation to turn on main relay 30.

[0070] In the implementation scheme, when the output voltage of the fuel cell 10 rises to equal to or higher than a preset voltage, the controller 50 can perform a control operation to turn on the main relay 30.

[0071] The controller 50 can perform control operations to perform inefficient operations, such as keeping the output voltage of the fuel cell 10 below a preset voltage when the main relay 30 is off, and increasing the output voltage of the fuel cell 10 when the output current of the fuel cell 10 is not exhausted by the COD resistor 40.

[0072] Here, the preset voltage can be preset to the minimum voltage used to drive auxiliary devices 21 and 22 or drive devices (not shown).

[0073] In another embodiment, the controller 50 can perform a control operation such that the main relay is turned on when the power generated by the fuel cell 10 is equal to or greater than the maximum power consumption of the COD resistor 40.

[0074] When the power generated by the fuel cell 10 increases to be equal to or greater than the maximum power consumption of the COD resistor 40, the controller 50 can control the main relay 30 to turn on.

[0075] Specifically, the controller 50 can cause the power generated by the fuel cell 10 to be consumed when the power consumption of the COD resistor 40 is increased, and when the power consumption of the COD resistor 40 reaches the maximum power consumption and therefore the power generated by the fuel cell 10 can no longer be consumed, the controller 50 can perform a control operation to turn on the main relay 30.

[0076] In another embodiment, even if the power consumption of the COD resistor 40 is not at its maximum, the controller 50 can still perform a control operation to turn on the main relay 30 when the sum of the power consumption of the auxiliary devices 21 and 22 or the drive device (not shown), the charging power of the high-voltage battery 60, and the power consumption of the COD resistor 40 is at its maximum. This is because, with the main relay 30 turned on, the cold start temperature rise load corresponds to the sum of the power consumption or charging power of the COD resistor 40, auxiliary devices 21 and 22, the drive device (not shown), and the high-voltage battery 60.

[0077] In another embodiment, the controller 50 can perform a control operation such that when the time consumed to supply power generated by the fuel cell 10 to the COD resistor 40 in the state where the main relay 30 is off is equal to or longer than a preset time, the main relay is turned on based on the sum of the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40.

[0078] Here, the preset time can be pre-set by experimentally measuring the time required to maximize the power consumption of the COD resistor 40 or the time required for the voltage at the output of the fuel cell 10 to rise to a preset voltage.

[0079] Specifically, the controller 50 can perform a control operation such that the main relay 30 is turned on when the sum of the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40 is maximized.

[0080] COD resistor 40 can be included in the cooling line used to cool fuel cell 10 to heat the coolant. Since the purpose of controlling the cold start of fuel cell 10 is to heat up the entire fuel cell system, the total calorific value can be the sum of the calorific value of fuel cell 10 (i.e., the calorific value generated by fuel cell 10 itself) and the COD calorific value generated by COD resistor 40.

[0081] During the cold start control of the fuel cell 10, the controller 50 can perform a control operation that increases the total calorific value, which is the sum of the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40. Specifically, the controller 50 can perform a control operation that increases the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40 when the main relay 30 is off during the initial stage of cold start control.

[0082] The controller 50 can perform a control operation such that the main relay 30 is turned on when the total calorific value, which is the sum of the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40, is maximized and no longer increases.

[0083] Furthermore, the system may further include a determining unit 70 configured to determine cold start conditions based on the temperature of the coolant circulating to cool the fuel cell 10 or the temperature of the air supplied to or exhausted from the fuel cell 10. When the determining unit 70 determines that the cold start conditions are met, the controller 50 may supply power generated by the fuel cell 10 to the COD resistor 40 while the main relay 30 is off.

[0084] The determining unit 70 can determine whether the cold start conditions of the fuel cell 10 are met. Specifically, the determining unit 70 can determine the cold start conditions based on the temperature of the coolant passing through the fuel cell 10 or the temperature of the air discharged from the fuel cell 10.

[0085] That is, since it is difficult to directly measure the temperature inside the fuel cell 10, the determining unit 70 can estimate the temperature inside the fuel cell 10 based on the temperature of the coolant or air passing through the fuel cell 10, thereby determining the cold start conditions.

[0086] In the implementation scheme, the determining unit 70 can determine whether the temperature of the coolant discharged through the fuel cell 10 or the temperature of the air supplied to the fuel cell 10 and then discharged from the fuel cell 10 is equal to or lower than a preset cold start temperature.

[0087] When the determining unit 70 determines that the cold start conditions are met, the controller 50 can control the fuel cell 10 to heat up when the power generated by the fuel cell 10 is supplied to the COD resistor 40 while the main relay 30 is off.

[0088] More specifically, when the determining unit 70 determines that the cold start conditions are met and the temperature of the coolant or air is equal to or higher than the preset temperature, the controller 50 may, by executing control to turn on the main relay 30, supply the power generated by the fuel cell 10 to the COD resistor 40 and the high-voltage battery 60, auxiliary devices 21 and 22 or drive device (not shown).

[0089] Here, the preset temperature can be set below the cold start temperature preset to determine the cold start conditions. When the temperature of the coolant or the air is lower than the preset temperature, the determination unit 70 can determine that it is a low temperature state.

[0090] Conversely, when the cold start conditions are determined to be met based on the temperature of the coolant or the temperature of the air, and when the temperature of the coolant or the temperature of the air is equal to or higher than the preset temperature, the determining unit 70 can determine that it is a normal cold start condition rather than a low temperature state.

[0091] When the determining unit 70 determines that the condition is a normal cold start condition rather than a cryogenic state, the controller 50 can perform a control operation to activate the main relay 30. Therefore, the power generated by the fuel cell 10 can be supplied to the COD resistor 40, the high-voltage battery 60, auxiliary devices 21 and 22, or a drive device (not shown). Thus, when the condition is not cryogenic, the time required to perform cold start control can be reduced.

[0092] Figure 3 A schematic diagram illustrating the calorific value generated by the fuel cell 10 in a system for controlling the cold start of the fuel cell 10 according to an embodiment of the present invention is provided.

[0093] Further reference Figure 3 According to an embodiment of the present invention, the system for controlling the cold start of the fuel cell 10 can operate the fuel cell 10 at the operating point for increasing the calorific value (stack calorific value) of the fuel cell 10 during the initial heating phase.

[0094] Specifically, during the initial heating phase, the controller 50 can control the COD resistor 40 to consume the electricity generated by the fuel cell 10 through heat generation (COD calorific value) while increasing the calorific value (stack calorific value) of the fuel cell 10 by maintaining a low voltage at the output of the fuel cell 10.

[0095] As the cold start control of the fuel cell 10 continues, during the intermediate heating phase, the operating point of the fuel cell 10 can shift in the direction where both the output current and output voltage of the fuel cell 10 increase. Therefore, the calorific value (COD calorific value) of the COD resistor 40, which consumes the electricity generated by the fuel cell 10, can gradually increase.

[0096] When the voltage at the output of the fuel cell 10 continues to increase, and when the voltage at the output of the fuel cell 10 rises to be equal to or higher than the preset voltage of the main relay 30 during the termination of the heating phase, the controller 50 may perform a control operation to turn on the main relay 30.

[0097] Furthermore, when the power consumption of the COD resistor 40 is at its maximum and cannot be increased further, the controller 50 can maintain the maximum COD calorific value and can turn on the main relay 30, thereby supplying power generated by the fuel cell 10 to the high-voltage battery 60, auxiliary devices 21 and 22 or drive device (not shown), in addition to supplying power to the COD resistor 40.

[0098] Under the preset voltage when the main relay 30 is turned on, the total calorific value, which is the sum of the COD calorific value and the stack calorific value, can be maximized.

[0099] Furthermore, during the termination heating phase after the main relay 30 is turned on, the operating point of the fuel cell 10 shifts in the direction of further increase in voltage and current at the output terminal. Therefore, the power generated by the fuel cell 10 may exceed the power consumption of the COD resistor 40. The power generated by the fuel cell 10 exceeding the power consumption of the COD resistor 40 can be used to charge the high-voltage battery 60, or it can be consumed by auxiliary devices 21 and 22 or a drive device (not shown).

[0100] Figure 4 This is a cold start flowchart of a method for controlling the cold start of a fuel cell 10 according to an embodiment of the present invention.

[0101] Further reference Figure 4 According to an embodiment of the present invention, a method for controlling the cold start of a fuel cell 10 includes: a step (S300) of supplying power generated by the fuel cell 10 while the main relay 30 of the main bus terminal 20 is off, wherein the main bus terminal 20 electrically connects the output terminal of the fuel cell 10 to a high-voltage battery 60, auxiliary devices 21 and 22 or a drive device (not shown); and a step (S400) of controlling a COD resistor 40 to consume the power generated by the fuel cell 10.

[0102] The COD resistor 40 can actively control power consumption through switching control, and in the step of controlling the COD resistor 40 (S400), the COD resistor 40 can be controlled to keep the output voltage of the fuel cell 10 below a preset voltage.

[0103] After the step of supplying power to COD resistor 40 (S300), the method may further include the step of discharging high-voltage battery 60 to supply power to auxiliary devices 21 and 22 or drive device (not shown) (S700).

[0104] The method may further include: monitoring the charge or output power of the high-voltage battery 60 before supplying power to the auxiliary devices 21 and 22 or the drive device (not shown) (S700); and performing control to turn on the main relay 30 when the monitored charge of the high-voltage battery 60 is equal to or less than a preset charge or the output power is equal to or less than a preset charge (S900).

[0105] After the step of controlling the COD resistor 40 (S400), the method may further include the following step (S800): by executing control such that when the output voltage of the fuel cell 10 is equal to or greater than a preset voltage, the main relay 30 is turned on (S900), and the power generated by the fuel cell 10 is supplied to the high-voltage battery 60, auxiliary devices 21 and 22 or drive device (not shown).

[0106] After the step of controlling the COD resistor 40 (S400), the method may further include the following step (S900): performing control such that the main relay 30 is turned on when the total power generated by the fuel cell 10 is equal to or greater than the maximum power consumption of the COD resistor 40 or when the sum of the calorific value of the fuel cell 10 and the calorific value of the COD resistor 40 is at its maximum.

[0107] Before the step of supplying power to the COD resistor 40 (S300), the method may further include a step of determining cold start conditions based on the temperature of the coolant circulating to cool the fuel cell 10 or the temperature of the air supplied to or discharged from the fuel cell 10 (S100). In the step of supplying power to the COD resistor 40 (S300), when it is determined that the cold start conditions are met, the power generated by the fuel cell 10 may be supplied to the COD resistor 40 while the main relay 30 is off.

[0108] After determining the cold start conditions (S100), the method may further include the following step (S200): in a state where the control is executed such that when the determining unit 70 determines that the cold start conditions are met and when the temperature of the coolant or the temperature of the air is equal to or higher than a preset temperature, the main relay 30 is turned on (S900), and the power generated by the fuel cell 10 is supplied to the COD resistor 40 and the high-voltage battery 60, auxiliary devices 21 and 22 or drive device (not shown).

[0109] Although the invention has been described and illustrated in conjunction with specific embodiments thereof, it will be apparent to those skilled in the art that various improvements and modifications may be made to the invention without departing from the inventive concept defined by the appended claims.

Claims

1. A system for controlling the cold start of a fuel cell, the system comprising: A fuel cell, configured to be supplied with fuel gas and oxidizing gas to generate electricity; The main bus is configured to electrically connect the output of the fuel cell to a high-voltage battery, auxiliary device, or drive device to output the power generated by the fuel cell. A main relay is disposed at the main bus terminal between the output terminal of the fuel cell and the high-voltage battery, auxiliary device or drive device, and the main relay is configured to electrically connect or disconnect the main bus terminal. COD resistors are based on a main relay connected to the main bus terminal on the output side of the fuel cell. as well as The controller is configured to supply power generated by the fuel cell to the COD resistor when the main relay is off, and to control the COD resistor to consume the power generated by the fuel cell and supplied to it. The controller is configured to perform a control operation such that when the time consumed to supply the power generated by the fuel cell to the COD resistor is equal to or longer than a preset time while the main relay is off, the main relay is turned on based on the maximum sum of the calorific value of the fuel cell and the calorific value of the COD resistor.

2. The system for controlling the cold start of a fuel cell according to claim 1, wherein, The COD resistor is configured to actively control power consumption via switching control. The controller is configured to control the COD resistor so that the output voltage of the fuel cell remains below a preset voltage.

3. The system for controlling a cold start of a fuel cell according to claim 1, wherein, The controller is configured to supply power to auxiliary or drive devices by discharging a high-voltage battery.

4. The system for controlling the cold start of a fuel cell according to claim 3, further comprising: The monitoring unit is configured to monitor the charge level or output power of the high-voltage battery. The controller is configured to perform a control operation such that when the power level of the high-voltage battery monitored by the monitoring unit is equal to or less than a preset power level, or when the power that can be output is equal to or less than a preset power level, the main relay is turned on.

5. The system for controlling a cold start of a fuel cell according to claim 1, wherein, The controller is configured to perform a control operation such that when the output voltage of the fuel cell is equal to or greater than a preset voltage, the main relay is turned on, thereby supplying the power generated by the fuel cell to the high-voltage battery, auxiliary device, or drive device.

6. The system for controlling a cold start of a fuel cell according to claim 1, wherein, The controller is configured to perform a control operation such that when the power generated by the fuel cell is equal to or greater than the maximum power consumption of the COD resistor, the main relay is turned on.

7. The system for controlling the cold start of a fuel cell according to claim 1, further comprising: The determining unit is configured to determine cold start conditions based on the temperature of the coolant circulating to cool the fuel cell or the temperature of the air supplied to or exhausted from the fuel cell. The controller is configured such that when the determining unit determines that the cold start conditions are met, the power generated by the fuel cell is supplied to the COD resistor while the main relay is off.

8. The system for controlling the cold start of a fuel cell according to claim 7, wherein, The controller is configured to supply power generated by the fuel cell to the COD resistor, high-voltage battery, auxiliary device, or drive device when the determining unit determines that the cold start conditions are met and the temperature of the coolant or the air is equal to or higher than a preset temperature, thereby turning on the main relay.

9. A method for controlling the cold start of a fuel cell, the method comprising: With the main relay at the main bus terminal off, power generated by the fuel cell is supplied. The main bus terminal is used to electrically connect the output of the fuel cell to a high-voltage battery, auxiliary device, or drive device. The COD resistor is controlled to consume the power generated by the fuel cell. After controlling the COD resistor, control is executed such that the main relay is turned on when the total power generated by the fuel cell is equal to or greater than the maximum power consumption of the COD resistor, or when the sum of the calorific value of the fuel cell and the calorific value of the COD resistor is at its maximum.

10. The method according to claim 9, wherein, The COD resistor is configured to actively control power consumption via switching control. When controlling the COD resistor, the COD resistor is controlled so that the output voltage of the fuel cell is kept below a preset voltage.

11. The method of claim 9, further comprising: After power is supplied to the COD resistor, the high-voltage battery is discharged to supply power to auxiliary or drive devices.

12. The method of claim 11, further comprising: Before supplying power to auxiliary or drive devices, monitor the charge level or available output power of the high-voltage battery. The execution control causes the main relay to be turned on when the detected high-voltage battery charge is equal to or less than the preset charge, or when the output power is equal to or less than the preset power.

13. The method of claim 9, further comprising: After controlling the COD resistor, the main relay is activated when the output voltage of the fuel cell is equal to or greater than the preset voltage, so that the power generated by the fuel cell is supplied to the high-voltage battery, auxiliary device or drive device.

14. The method of claim 9, further comprising: Before supplying power to the COD resistor, cold start conditions are determined based on the temperature of the coolant circulating to cool the fuel cell or the temperature of the air supplied to or exhausted from the fuel cell. Specifically, when supplying power to the COD resistor, if the cold start conditions are determined to be met, the power generated by the fuel cell will be supplied to the COD resistor while the main relay is off.

15. The method of claim 14, further comprising: After determining the cold start conditions, the main relay is activated when the cold start conditions are met and the temperature of the coolant or air is equal to or higher than a preset temperature. In this state, the power generated by the fuel cell is supplied to the COD resistor, high-voltage battery, auxiliary devices, or drive devices.

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