SYSTEM AND METHOD FOR CONTROLLING A FUEL CELL

Abstract

A fuel cell control system comprising: a fuel cell (10) supplied with both hydrogen and oxygen and configured to generate electrical current by means of a chemical reaction therein; a cooling system (20) with a heat exchanger (21) capable of exchanging heat with outside air, the cooling system (20) being configured to circulate cooling water therein and exchange heat with the fuel cell (10); a temperature sensing unit (30) configured to detect a fuel cell temperature or a cooling water temperature in the cooling system (20); a cooling control unit (40) configured to control the cooling system (20) so that the fuel cell (10) is additionally cooled when the fuel cell (10) ceases to generate electrical energy if the fuel cell temperature or the cooling water temperature detected by the temperature sensing unit (30)a monitoring unit (50) configured to monitor the magnitude of electrical power or current output by the fuel cell (10) when the fuel cell (10) generates electrical power, wherein the cooling control unit (40) is configured to control the cooling system (20) to provide additional cooling to the fuel cell (10) when power generation stops when the monitored magnitude of electrical power or current from the fuel cell (10) is equal to or greater than a predetermined high-power reference or a predetermined high-current reference, and a timing unit (60) configured to accumulate and measure a period during which the magnitude of electrical power or currentthe monitoring unit (50) monitors whether the power consumption of the fuel cell (10) is equal to or higher than the predetermined high-power reference or the predetermined high-current reference since the fuel cell (10) was started, wherein the cooling control unit (40) is configured to control the cooling system (20) so that the fuel cell (10) is additionally cooled when power generation stops, when the time measured and accumulated by the timing unit (60) is equal to or longer than a predetermined time.

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present disclosure relates to a system and method for controlling a fuel cell, and more particularly to a system for recovering power after continued high power operation of a fuel cell. background

[0002] A fuel cell is configured to convert chemical energy into electrical energy by utilizing an oxidation-reduction reaction of hydrogen and oxygen supplied from a hydrogen and air supply device, respectively, and includes a fuel cell stack for generating electrical energy, a cooling system for cooling the fuel cell stack, and the like.

[0003] This means that hydrogen is fed to the anode of the fuel cell. An oxidation reaction of the hydrogen takes place in the anode, producing protons and electrons. The resulting protons and electrons migrate through an electrolyte film and a separator plate to the cathode. In the cathode, electrical energy is generated through an electrochemical reaction involving the protons and electrons of the anode and the oxygen in the air.

[0004] Fuel cells have been introduced not only for passenger cars but also for sport utility vehicles (SUVs). Fuel cells are also suitable for commercial vehicles such as buses and trucks, which require high performance to ensure long-distance travel and provide environmentally friendly benefits.

[0005] Particularly in the commercial vehicle sector, the problem is that although it is possible to drive at high power for long distances or with high loads, the maximum cooling capacity of the cooling system of the fuel cell vehicle is limited, so that the fuel cell inevitably operates at high temperatures.

[0006] A passenger car or an SUV may have control devices to limit the fuel cell's power output to prevent high-temperature operation of the fuel cell. However, in the case of a commercial vehicle, it is difficult to limit the power output because of the possibility of the vehicle stalling, causing stability problems. Therefore, fuel cells used in commercial vehicles are exposed to high temperatures, which degrades performance and poses a problem of durability deterioration.

[0007] The above descriptions are merely intended to facilitate understanding of the background of the present disclosure and are not to be considered prior art by one skilled in the art. BRIEF EXPLANATION

[0008] The present disclosure has been made to solve the above-mentioned problems, and one aspect of the present disclosure is to provide a technique for performing cooling control so that when a fuel cell continues to generate high power, the performance of the fuel cell is restored or a recovery occurs when the fuel cell stops generating electric power.

[0009] In accordance with one aspect of the present disclosure, a fuel cell control system is provided, comprising: a fuel cell supplied with both hydrogen and oxygen and configured to generate electrical power by means of a chemical reaction therein, a cooling system having a heat exchange device capable of exchanging heat with outside air, the cooling system configured to circulate cooling water therein and exchange heat with the fuel cell, a temperature detection unit configured to detect a fuel cell temperature and / or a cooling water temperature in the cooling system, and a cooling control unit configured to control the cooling system such that the fuel cell additionally (e.g. further orafter-cooling when the fuel cell stops generating electrical power, if the fuel cell temperature and / or the cooling water temperature detected by the temperature detection unit while the fuel cell is generating electrical power is equal to or higher than a preconfigured or predetermined (hereinafter referred to as predetermined) power drop temperature (e.g., power deterioration temperature at which power deterioration (e.g., reduced cell voltage) occurs).

[0010] The temperature detection unit can, for example, measure the temperature of the cooling water flowing into the inlet of the fuel cell under or in the cooling water in the cooling system.

[0011] The fuel cell control system may, for example, further comprise a monitoring unit configured to monitor the magnitude of the electrical power and / or current output by the fuel cell when the fuel cell is generating electrical power. The cooling control unit may, for example, control the cooling system such that the fuel cell is additionally cooled when power generation stops if the monitored magnitude of the electrical power or current from the fuel cell is equal to or higher than a predetermined high-power reference or a predetermined high-current reference.

[0012] The fuel cell control system may, for example, further comprise a time measurement unit configured to accumulate and measure a time (duration) during which the electric power and / or electric current value monitored by the monitoring unit is maintained equal to or higher than the predetermined high-power reference or the predetermined high-current reference since the fuel cell was started. The cooling control unit may, for example, control the cooling system such that the fuel cell is additionally cooled when power generation stops if the accumulated time measured by the time measurement unit is equal to or longer than a predetermined time.

[0013] For example, the cooling control unit may control the cooling system to cool the fuel cell for a predetermined first recovery time (duration) since the request to stop power generation by the fuel cell.

[0014] The cooling control unit may, for example, control the cooling system so that the fuel cell is cooled for a predetermined second recovery time after the cooling water has cooled to a predetermined recovery temperature.

[0015] The cooling system may, for example, include a cooling (water) pump configured to circulate cooling water, and a cooling fan configured to circulate outside air near (e.g., through) a radiator. The cooling control unit may, for example, control the speed of the cooling pump and / or the speed of the cooling fan to a maximum level until the cooling water temperature drops to a predetermined recovery temperature, and may control the cooling system to maintain the cooling water temperature at the predetermined recovery temperature for a second recovery period.

[0016] The fuel cell control system may, for example, further comprise a start-up control unit configured to determine whether or not the cooling system is to be controlled by the cooling control unit when shutdown of the fuel cell is requested, and to control shutdown of the fuel cell after the cooling control unit has completed controlling or operating the cooling system.

[0017] In accordance with another aspect of the present disclosure, there is provided a fuel cell control method comprising: detecting a fuel cell temperature and / or cooling water temperature in a cooling system when a fuel cell is generating electric power, comparing the detected fuel cell temperature and / or cooling water temperature with a predetermined power drop temperature, and controlling the cooling system to additionally cool the fuel cell when the fuel cell stops generating electric power when the detected fuel cell temperature or cooling water temperature is equal to or higher than the predetermined power drop temperature.

[0018] The fuel cell control method may further include monitoring the magnitude of the electric power or electric current output from the fuel cell when the fuel cell is generating electric power before controlling the cooling system. The cooling system may be controlled to additionally cool the fuel cell when power generation stops if the monitored magnitude of the electric power or electric current output from the fuel cell is equal to or higher than a predetermined high-power reference or a predetermined high-current reference.

[0019] The fuel cell control method may, for example, further comprise accumulating and measuring a time during which the magnitude of the electric power or electric current monitored after the fuel cell is started is maintained equal to or higher than the predetermined high-power reference or the predetermined high-current reference after the magnitude of the electric power or electric current is monitored. During the step of controlling the cooling system, the cooling system may, for example, be controlled such that the fuel cell is additionally cooled when power generation stops if the accumulated time measured by a time measuring unit is equal to or longer than a predetermined time.

[0020] In the cooling system control step, the cooling system may be controlled, for example, to cool the fuel cell for a predetermined second recovery time after the cooling water has cooled to a predetermined recovery temperature.

[0021] In the cooling system control step, for example, the speed of a cooling pump and / or the speed of a cooling fan can be controlled to a maximum level until the cooling water temperature drops to a predetermined recovery temperature.

[0022] The fuel cell control method may further comprise, for example, controlling the shutdown of the fuel cell after completion of the control of the cooling system by or through the cooling control unit when the shutdown control of the fuel cell is requested after the control of the cooling system.

[0023] The system and method for controlling a fuel cell according to the present disclosure are advantageous in that the performance of a fuel cell stack that is degraded when the fuel cell generates electric power is restored.

[0024] In addition, the efficiency of power generation is improved by the power recovery of the fuel cell, thereby improving fuel efficiency.

[0025] In addition, the deterioration of the fuel cell stack is delayed, thereby improving durability and extending the service life of the fuel cell stack. Character list

[0026] The above and other aspects and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a diagram showing the configuration of a fuel cell control system according to an embodiment of the present disclosure, Fig. 2 shows the power loss resulting from high-power operation of a fuel cell under different conditions, Fig. 3 is a diagram showing the operating temperature of a fuel cell, Fig. 4 is a tabular view showing the performance degradation of a fuel cell depending on a cooling condition in an interruption section, and Fig. 5 is a flowchart of a fuel cell control method according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0027] Any specific structural or functional description of embodiments of the present disclosure disclosed in the specification or application is provided solely for the purpose of describing the embodiment according to the present disclosure. Therefore, the embodiments according to the present disclosure may be implemented in various ways, and the present disclosure should not be construed as being limited to the embodiments described in the specification or application.

[0028] Various changes and modifications may be made to the embodiments according to the present disclosure, and therefore, specific embodiments are illustrated in the drawings and described in the specification or application. It is to be understood that embodiments according to the concept of the present disclosure are not limited to the particular embodiments disclosed, but that the present disclosure includes all changes, equivalents, and alternatives falling within the scope of the present disclosure.

[0029] Although the terms "atomic numbers" such as first, second, and the like may be used to describe various elements, the elements should not be defined by such terms. The terms are used merely to distinguish one element from another, so that a first element may be referred to as a second element, while the second element may be referred to in a similar manner to the first element, without departing from the scope of protection according to the concept of the present disclosure.

[0030] When an element is described as being "connected" or "connected" to other elements, it should be understood that not only is the element directly connected or connected to the other elements, but that another element may also exist between them. In contrast, when a component is described as being "directly connected" or "directly connected" to another component, it should be assumed that there is no component between them. The other expressions used to describe a relationship between structural elements, i.e., "between" and "merely between" or "adjacent" and "directly adjacent," should be interpreted similarly to the above description.

[0031] In this specification, the terms are used merely to describe a particular embodiment and are not intended to be limiting of the present disclosure. As used herein, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise. Throughout this specification, the terms "including" or "comprising" indicate the presence of one feature, number, step, operation, structural element, parts, or combination thereof and do not preclude the presence or likelihood of the addition of one or more other features, numbers, steps, operations, structural elements, parts, or combinations thereof.

[0032] Unless otherwise defined, all terms used herein that include technical or scientific terminology have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. It is understood that terms identical to those defined in common dictionaries have the same meaning as they do in the context of the related art. These terms should not be interpreted in an ideal or overly formal manner unless so defined.

[0033] A preferred embodiment of the present disclosure will now be described in detail with reference to the accompanying drawings. Like reference numerals throughout the drawings indicate similar elements.

[0034] Fig. 1 is a diagram showing the configuration of a system for controlling a fuel cell 10according to an embodiment of the present disclosure.

[0035] With reference to the Fig. 1 shows the system for controlling a fuel cell 10 according to one embodiment of the present disclosure: a fuel cell 10 , which is supplied with both hydrogen and oxygen and is designed to generate electrical current through a chemical reaction therein, a cooling system 20 with a heat exchanger device 21 which is able to exchange heat with outside air, whereby the cooling system 20 is designed to circulate or flow cooling water and exchange heat with the fuel cell 10 to replace a temperature detection unit 30 which is set up to control the temperature of the fuel cell 10 or the cooling water temperature in the cooling system 20 and a cooling control unit 40which is designed to cool the cooling system 20 to control the fuel cell 10 additionally or further cools when the fuel cell 10 stops generating electrical power when the temperature of the fuel cell 10 or the cooling water temperature measured by the temperature detection unit 30 is recorded while the fuel cell 10 generates electrical power is equal to or higher than a predetermined power decay temperature.

[0036] The fuel cell 10 refers to a fuel cell stack 10 including several stacked cell units. The fuel cell 10 can be supplied with hydrogen from a hydrogen supply system and can be supplied with oxygen contained in the air from an air supply system, thereby triggering a chemical reaction therein.

[0037] Through the reaction of hydrogen and oxygen in the fuel cell 10 Electrons can be moved, generating an electric current and electrical power. In addition, the chemical reaction of hydrogen and oxygen in the fuel cell can 10 water, generating additional thermal energy.

[0038] The cooling system 20 can circulate cooling water to cool the fuel cell 10 to dissipate the heat generated to the outside. The cooling system 20 can a cooling pump 22 for circulating the cooling water, a heat exchanger device 21 to discharge the circulating cooling water to the outside (e.g. from the fuel cell) so that it can exchange heat with the outside air, and a cooling fan 23 for circulating or flowing outside air near the heat exchanger device 21whereby the heat exchange of the heat exchanger device 21 is reinforced.

[0039] In addition, the cooling system 20 a flow rate adjustment valve 24 for adjusting the flow rate ratio between the cooling water supplied to the heat exchanger device 21 (cooler) and the cooling water that flows through the heat exchanger 21 bypasses.

[0040] The cooling control unit 40 the cooling pump can 22 , the cooling fan 23 and the flow rate adjustment valve 24 of the cooling system 20 and thereby the cooling of the fuel cell 10 In particular, the speed of the cooling pump 22 and the cooling fan 23 or the degree of opening of the flow rate adjustment valve 24 controlled, whereby the temperature or the flow rate of the fuel into the fuel cell 10flowing cooling water.

[0041] The temperature detection unit 30 the temperature of the fuel cell 10 or the cooling water temperature in the cooling system 20 capture, while the fuel cell 10 electricity is generated. Since it is difficult to control the temperature of the fuel cell 10 To measure directly, the temperature measuring unit 30 the temperature of the fuel cell 10 based on the cooling water temperature near the inlet or outlet of the fuel cell 10 estimate.

[0042] The cooling control unit 40 the fuel cell can 10 cool when the fuel cell 10 ceases to generate electrical power. As used herein, stopping or terminating power generation may refer to the fact that the power generation by the fuel cell 10is interrupted while the fuel cell 10 remains switched on (e.g. idle stop (FC STOP)), or that the fuel cell 10 is switched off.

[0043] In general, the energy used in the fuel cell 10 ongoing chemical reaction is interrupted when the fuel cell is switched off 10 or entry into the idle stop mode is requested, and the cooling control of the fuel cell 10 will also be interrupted accordingly.

[0044] The cooling control unit 40 According to one embodiment of the present disclosure, the cooling system 20 control it so that the fuel cell 10 additionally or further cools when requested that the fuel cell 10 is switched off or enters idle stop mode. In particular, the cooling control unit 40 the cooling system 20control it so that the fuel cell 10 additionally or further cools when the temperature of the fuel cell 10 or the cooling water temperature measured by the temperature detection unit 30 is detected when the fuel cell 10 generates electrical power is equal to or higher than a predetermined power decay temperature.

[0045] The predetermined power drop temperature may be a predetermined high temperature at which a power drop of the fuel cell 10 is more likely. Accordingly, it is determined whether the fuel cell 10 was exposed to a high temperature or not, while the fuel cell 10 generates electrical power, and whether the fuel cell 10 is cooled when the fuel cell 10 stops generating electricity if it has been exposed to a high temperature, which reduces the performance of the fuel cell10 is restored. Specifically, the cooling system cools 20 the fuel cell 10 so that steam inside the fuel cell 10 condenses, which has reached a state of dehydration. Accordingly, the humidity is increased, so that the fuel cell 10 reaches a moist state, which reduces the performance of the fuel cell 10 is recovered.

[0046] The temperature recording unit 30 the temperature of the cooling water can be below the cooling water in the cooling system 20 measure that enters the inlet of the fuel cell 10 flows.

[0047] The temperature recording unit 30 The temperature of the cooling water at different points in the cooling system 20 measure or the temperature of the fuel cell 10 In particular, the temperature detection unit 30measure the temperature of the cooling water entering the fuel cell inlet 10 flows.

[0048] If the temperature of the cooling water entering the fuel cell inlet 10 is equal to or higher than the predetermined power drop temperature, it is difficult to start the fuel cell 10 to a temperature below the predetermined power drop temperature. In such a situation, the operating temperature of the fuel cell 10 kept above the predetermined power drop temperature.

[0049] The fuel cell control system can also include a monitoring unit 50 to monitor the magnitude of the electrical power or current supplied by the fuel cell 10 is released when the fuel cell 10 generates electrical power. The cooling control unit 40 the cooling system 20control it so that the fuel cell 10 additionally cools when power generation stops, when the monitored amount of electrical power or electrical current from the fuel cell 10 equal to or higher than a predetermined high power reference or a predetermined high current reference.

[0050] The monitoring unit 50 The size of the fuel cell 10 monitor the output electrical power or electrical current while the fuel cell is generating electrical power. The monitoring unit 50 can be connected to a voltage or current sensor to measure the voltage or current from a main bus stage connected between the fuel cell 10 and is connected to a drive system (e.g. a motor).

[0051] The cooling control unit 40 can determine whether the size of the fuel cell 10delivered or generated electrical power is equal to or higher than a predetermined high-power reference or not, or whether the size of the fuel cell 10 output electrical current is equal to or higher than a predetermined high current reference or not, and the fuel cell can 10 additional cooling when power generation stops when the high power reference or the high current reference is exceeded.

[0052] The fuel cell control system may also include a timing unit 60 which is arranged to accumulate and measure a time (duration) during which the magnitude of the electrical power or the electrical current from the fuel cell 10 , which is carried out by the monitoring unit 50 has been monitored since the launch of the fuel cell 10is maintained equal to or higher than the predetermined high-power reference or the predetermined high-current reference. The cooling control unit 40 the cooling system 20 so that the fuel cell 10 is additionally cooled when power generation stops, when the time measurement unit 60 measured accumulated time is equal to or longer than a predetermined time.

[0053] The unit of time measurement 60 can measure the time during which the monitored quantity of electrical power or current from the fuel cell 10 equal to or higher than the predetermined high power reference or the predetermined high current reference. In particular, the time measuring unit 60 which since the launch of the fuel cell 10 Measure the accumulated time until the fuel cell 10 power generation stops.

[0054] The cooling control unit 40the cooling system 20 so that the fuel cell 10 is only cooled additionally if the measured accumulated time is longer than the predetermined time. This means that a control can be requested so that when the fuel cell 10 is operated continuously at high power over a longer period of time, the fuel cell 10 cooled and thus restored.

[0055] In a further embodiment, the cooling control unit 40 the recovery time during which the fuel cell 10 additional or further cooling is carried out, in proportion to the measured accumulated time.

[0056] If the fuel cell 10 operated at high power, the fuel cell can 10 due to insufficient cooling performance of the cooling system 20 exposed to high temperatures. If the fuel cell10 exposed to a high temperature, the air inlet through which air enters the fuel cell 10 flows into the fuel cell, a drying state occurs, and the (e.g. dried-out) area increases over time. This leads to a problem in that the internal resistance of the fuel cell 10 This means that the high-performance operation of the fuel cell 10 a deterioration or decrease in the performance of the fuel cell follows 10 .

[0057] In addition, with the expansion of the drying state through the air inlet of the fuel cell 10 the resistance of a fuel cell 10 This leads to irreversible damage to the fuel cell 10 . In addition, when the fuel cell is restarted 10maintain a lower power due to the deterioration in performance. This increases the heat generated by the reaction of hydrogen and oxygen, which raises the problem of a further increase in the operating temperature of the fuel cell 10 presents.

[0058] Fig. 2 shows the performance degradation resulting from the high-performance operation of the fuel cell 10 under different conditions.

[0059] With reference to Fig. 2 is the average cell voltage of the fuel cell 10 in conjunction with continued operation of the fuel cell 10 shown in every state. Fig. 2 includes in particular the test data under operating conditions of the fuel cell 10 for several tens of hours.

[0060] Specifically, the average cell voltage refers to the average voltage of the unit cells used in the fuel cell 10 are included, while the fuel cell 10 the same current. A decrease in the average cell voltage at the same output current means a decrease in the output power of the fuel cell 10 This means that a decrease in the average cell voltage shown means a deterioration or a drop in the performance of the fuel cell 10 .

[0061] First, (1) corresponds to a situation where the fuel cell 10 continuously delivers a high current and corresponds to a state in which the fuel cell 10 operated without interruption of power generation (without stopping power generation). A deterioration in the performance of the fuel cell 10as a result of continuous high-current operation of the fuel cell 10 can be confirmed.

[0062] In the situation of (2), the fuel cell 10 operated in such a way that it alternately delivers a high current and a lower current, and this corresponds to a state in which the fuel cell 10 without interruption of power generation. It can be confirmed that the performance of the fuel cell 10 continuously deteriorates if no interruption period is included (e.g., an interruption period is a period of time during which the fuel cell does not generate power but is cooled).

[0063] In the cases of (3) and (4), the fuel cell 10 operated in such a way that it alternately delivers a high and a lower current, and the power generation by the fuel cell 10is interrupted every two hours. This means that under the conditions of (3) and (4) the power generation by the fuel cell is interrupted every two hours. 10 is carried out.

[0064] In particular, in case of (3), a suspension or interruption period of ten minutes is maintained, and in case of (4), a suspension or interruption period of ten seconds is maintained. In both cases of (3) and (4), cooling water is circulated to cool the fuel cell. 10 to cool in each interruption section.

[0065] It can be confirmed that in cases (3) and (4) the cooling system 20 is controlled to the fuel cell 10 to cool when power generation is interrupted, thereby increasing the performance of the fuel cell 10In particular, by comparing the result of (3) with the result of (4), it can be confirmed that the higher performance of the fuel cell 10 is maintained the longer the interruption period lasts.

[0066] In cases (5) and (6) the fuel cell 10 operated to continuously deliver a high current, and the power generation by the fuel cell 10 is interrupted every two hours. This means that under the conditions of (5) and (6), an interruption of power generation is provided every two hours.

[0067] In the case of (5), the interruption period is maintained for ten seconds, so that natural cooling occurs. In the case of (6), the interruption period is maintained for one minute, and the cooling system 20is controlled so that the cooling water circulates. A comparison of the result of (6) with the result of (5) confirms that the circulation of cooling water at a low temperature during the interruption period improves the cooling performance, thereby resulting in better performance of the fuel cell. 10 is maintained.

[0068] Fig. 3 is a diagram illustrating the operating temperature of the fuel cell 10 . Fig. 4 is a table showing the performance degradation of the fuel cell 10 depending on a cooling condition in an interruption section.

[0069] With further reference to Fig. 3 and Fig. 4, the tests are repeated under the conditions of (1) to (3) that the fuel cell 10 in an interruption phase in the operation of the fuel cell 10cooled to deliver a high current, while the operating temperature of the fuel cell 10 is varied.

[0070] A comparison of the results from (1) to (3) confirms that at a relatively low operating temperature of the fuel cell 10 Although only a slight deterioration in performance occurs, the deterioration in performance of the fuel cell 10 gradually increases to a significant level as the operating temperature gradually increases.

[0071] This means that the higher the temperature the fuel cell 10 exposed to, the greater the deterioration in the performance of the fuel cell 10 .

[0072] Under the condition of (4), the tests are carried out during operation of the fuel cell 10repeatedly to output a high current, and it is naturally cooled for a short interruption period so that the temperature of the fuel cell 10 by 5 [°C].

[0073] A comparison between result (4) and the results from (1) to (3) confirms that performance deterioration occurs when the temperature of the fuel cell 10 does not drop sufficiently during the interruption period, even if the fuel cell 10 operated at a relatively low temperature.

[0074] Accordingly, it can be confirmed that the performance of the fuel cell 10 can be restored when the temperature of the fuel cell 10 is reduced by using the fuel cell 10 is sufficiently cooled during the interruption period (during the suspension or interruption of power generation).

[0075] This means that the performance of the fuel cell 10 can only be restored if the fuel cell 10 is sufficiently cooled by forced cooling.

[0076] In addition, under the conditions of (5) and (6), the tests during operation of the fuel cell 10 repeatedly to achieve a high current at a relatively high temperature of the fuel cell 10 while maintaining a long break section or a short break section.

[0077] In particular, under the condition of (5), the fuel cell 10 cooled to 35 [°C] by forced cooling with cooling water at 35 [°C] for a longer period of time. Under the condition of (6), the fuel cell 10 briefly forced-cooled, whereby the fuel cell 10 so it is not cooled sufficiently.

[0078] From the results of (5) and (6) it is clear that even if the fuel cell 10 operated at a relatively high temperature, the performance of the fuel cell 10 after a sufficient interruption time (duration). In addition, it is difficult to determine the performance of the fuel cell 10 adequately restore if the interruption period does not last for a sufficiently long period.

[0079] In summary, the performance of the fuel cell 10 can only be restored if the fuel cell 10 is cooled for a sufficient time when the fuel cell 10 stops generating electricity.

[0080] According to one embodiment, the cooling control unit 40 the cooling system 20 control it so that the fuel cell 10for a predetermined first recovery time, which is required when a request to suspend or interrupt power generation by the fuel cell 10 is initiated.

[0081] The cooling control unit 40 the fuel cell can 10 control it to stop power generation on demand in order to prevent power generation by the fuel cell 10 In one embodiment, the cooling control unit 40 the air supply to the fuel cell 10 control so that the air supply is interrupted.

[0082] At the same time, the cooling control unit 40 the cooling system 20 control it so that the fuel cell 10 for a predetermined first recovery time. The predetermined first recovery time may be predetermined to last approximately 30 minutes or longer, which is sufficient time for the vapor inside the fuel cell 10undergoes a change of state into a droplet or condensation state.

[0083] According to a further embodiment, the cooling control unit 40 the cooling system 20 control it so that the fuel cell 10 for a predetermined second recovery time after the cooling water has been cooled to a predetermined recovery temperature.

[0084] The cooling control unit 40 the cooling system 20 control it so that the fuel cell 10 when a request to stop power generation by the fuel cell 10 cools, and can cool the cooling water to a predetermined recovery temperature. In particular, the cooling control unit 40 the cooling system 20 control it so that the fuel cell 10cools for a predetermined second recovery time after the cooling water (temperature) has dropped to a predetermined recovery temperature.

[0085] As used herein, the temperature of the cooling water refers to a temperature measured by the temperature sensing unit 30 measured temperature and can be the temperature of the cooling water that enters the inlet of the fuel cell 10 flows. The predetermined recovery temperature can be approximately 30°C.

[0086] That is, the cooling control unit 40 the fuel cell can 10 cool while maintaining the cooling water for a predetermined second recovery time.

[0087] The cooling system 20 can a cooling pump 22 for the circulation of the cooling water and a cooling fan 23 for the circulation of outside air near the cooler.

[0088] The cooling control unit 40the speed of the cooling pump 22 or the speed of the cooling fan 23 to a maximum level until the cooling water temperature drops to a predetermined recovery temperature, and the cooling system can 20 control so that the cooling water temperature is maintained at the predetermined recovery temperature for a second recovery time.

[0089] The cooling control unit 40 can stop the power generation by the fuel cell when required 10 the speed of the cooling pump 22 or the speed of the cooling fan 23 to a maximum level until the cooling water temperature drops to a predetermined recovery temperature.

[0090] This increases the temperature of the cooling system 20 that the fuel cell 10 cools, suddenly reduced, whereby the fuel cell 10 cooled so that the recovery of the fuel cell 10can be maximized.

[0091] The cooling control unit 40 the cooling system 20 so that when the temperature of the cooling system 20 drops to the predetermined recovery temperature, the predetermined recovery temperature is maintained thereafter. That is, the speed of the cooling pump 22 and the speed of the cooling fan 23 can be controlled to maintain the cooling water temperature at the predetermined recovery temperature.

[0092] The fuel cell control system can also include a start control unit 70 which is set up to determine whether the cooling system 20 from the cooling control unit 40 should be controlled or not when the fuel cell is switched off 10 is requested, and to switch off the fuel cell 10 to control after controlling the cooling system 20 from the cooling control unit40 is completed.

[0093] If an input to switch off the fuel cell 10 is received, the fuel cell can be switched off 10 be requested. The shutdown control of the fuel cell 10 can be a control for maintaining or providing the fuel cell 10 which has stopped power generation for a long time (e.g. control of cathode oxygen depletion (COD)).

[0094] The start control unit 70 can determine whether the cooling system 20 from the cooling control unit 40 should be controlled or not. In particular, the start control unit 70 immediately shut down the fuel cell 10 if there is no requirement that the cooling control unit 40 the cooling system 20 controls the fuel cell 10 additional cooling.

[0095] However, if there is a requirement that the cooling control unit 40 the cooling system 20 controls, the start control unit 70 switching off the fuel cell 10 control (e.g. delay) after the cooling control unit 40 controlling the cooling system 20 has finished.

[0096] Fig. 5 is a flowchart of a method for controlling a fuel cell 10 according to an embodiment of the present disclosure.

[0097] Referring to Fig. 5 shows the method for controlling a fuel cell 10 according to one embodiment of the present disclosure, the following steps: detecting the temperature of the fuel cell 10 or the cooling water temperature of the cooling system 20 when the fuel cell 10 Electricity generated ( S100 ), comparing the recorded temperature of the fuel cell 10or the detected cooling water temperature with a predetermined power drop temperature ( S400 ), and controlling the cooling system 20 to the fuel cell 10 additional cooling when the fuel cell 10 stops generating electricity ( S300 ) when the detected temperature of the fuel cell 10 or the detected cooling water temperature is equal to or higher than the predetermined power drop temperature ( S600 ).

[0098] The method may further comprise a step of monitoring the magnitude of the electric current or the 10 output power when the fuel cell 10 Power generated ( S100 ) before the step to control the cooling system 20 ( S600 ) takes place. In the cooling step of the cooling system 20 ( S600 ) the cooling system 20 be controlled so that the fuel cell 10additionally cools when power generation stops, when the monitored amount of electrical power or current from the fuel cell 10 is equal to or higher than a predetermined high power reference or a predetermined high current reference.

[0099] The method may further comprise a step of accumulating and measuring the time during which the magnitude of the electric power or electric current from the fuel cell 10 which, after the start of the fuel cell 10 monitored, equal to or higher than the predetermined high power reference or the predetermined high current reference ( S200 ), after the step of monitoring the magnitude of the electrical power or current ( S100 ). In the step of controlling the cooling system 20 ( S600 ) the cooling system 20 be controlled so that the fuel cell 10additionally cools when power generation stops, when the timer unit 60 measured accumulated time is equal to or longer than a predetermined time ( S500 ).

[0100] In the step of controlling the cooling system 20 ( S400 ) the cooling system 20 be controlled so that the fuel cell 10 for a second recovery period after the cooling water has cooled to a predetermined recovery temperature.

[0101] In the step of controlling the cooling system 20 ( S600 ) the speed of the cooling pump 22 or the speed of the cooling fan 23 controlled to a maximum level until the cooling water temperature falls to a predetermined recovery temperature, and the cooling system 20 can be controlled to maintain the cooling water temperature at the predetermined recovery temperature for a second recovery time.

[0102] The method may further comprise a step for controlling the shutdown of the fuel cell 10 after completing the control of the cooling system 20 from the cooling control unit 40 when the shutdown control of the fuel cell 10 ( S700 ) after the step of controlling the cooling system 20 ( S600 ) is requested.

[0103] The temperature detection unit 30 , the cooling control unit 40 , the monitoring unit 50 , the unit of time measurement 60 and the start control unit 70According to an exemplary embodiment of the present disclosure, a non-volatile memory (not shown) configured to store an algorithm configured to control operations of various components of a vehicle or data relating to software instructions for reproducing the algorithm, and a processor (not shown) configured to perform operations described below using the data stored in the memory. The memory and processor may be implemented as individual chips. Alternatively, the memory and processor may be implemented as a single integrated chip. The processor may be in the form of one or more processors.

[0104] Although the present disclosure has been described and illustrated with reference to particular embodiments, it will be apparent to those skilled in the art that various improvements and modifications can be made to the present disclosure without departing from the technical spirit of the present disclosure as conveyed by the following claims.

Claims

[1] A fuel cell control system comprising: a fuel cell (10) supplied with both hydrogen and oxygen and arranged to generate electrical current by a chemical reaction therein, a cooling system (20) having a heat exchange device (21) capable of exchanging heat with outside air, the cooling system (20) being arranged to circulate cooling water therein and to exchange heat with the fuel cell (10), a temperature detection unit (30) configured to detect a fuel cell temperature or a cooling water temperature in the cooling system (20), and a cooling control unit (40) configured to control the cooling system (20) such that the fuel cell (10) is additionally cooled when the fuel cell (10) stops generating electrical power if the fuel cell temperature or the cooling water temperature detected by the temperature detection unit (30) while the fuel cell (10) is generating electrical power is equal to or higher than a predetermined power drop temperature. [2] The fuel cell control system according to claim 1, wherein the temperature detection unit (30) is arranged to measure the temperature of the cooling water flowing into an inlet of the fuel cell (10) among the cooling water in the cooling system (20). [3] The fuel cell control system according to claim 1 or 2, further comprising a monitoring unit (50) configured to monitor the magnitude of the electric power or the electric current output from the fuel cell (10) when the fuel cell (10) generates electric power, wherein the cooling control unit (40) is configured to control the cooling system (20) so that the fuel cell (10) is additionally cooled when power generation stops when the monitored magnitude of the electric power or the electric current from the fuel cell (10) is equal to or higher than a predetermined high-power reference or a predetermined high-current reference. [4] The fuel cell control system according to claim 3, further comprising a time measuring unit (60) configured to accumulate and measure a time during which the magnitude of the electric power or the electric current monitored by the monitoring unit (50) is maintained equal to or higher than the predetermined high-power reference or the predetermined high-current reference since the start of the fuel cell (10), wherein the cooling control unit (40) is configured to control the cooling system (20) so that the fuel cell (10) is additionally cooled when the power generation stops when the time measured and accumulated by the time measuring unit (60) is equal to or longer than a predetermined time. [5] The fuel cell control system according to any one of the preceding claims, wherein the cooling control unit (40) is arranged to control the cooling system (20) so that the fuel cell (10) is cooled for a predetermined first recovery time since a request to stop power generation by the fuel cell (10). [6] The fuel cell control system according to any one of the preceding claims, wherein the cooling control unit (40) is arranged to control the cooling system (20) to cool the fuel cell (10) for a predetermined second recovery time after the cooling water has cooled to a predetermined recovery temperature. [7] The fuel cell control system according to claim 6, wherein the cooling system (20) comprises a cooling pump (22) configured to circulate cooling water and a cooling fan (23) configured to circulate outside air to the vicinity of a radiator (21), and the cooling control unit (40) is configured to control the rotational speed of the cooling pump (22) and / or the rotational speed of the cooling fan (23) to a maximum level until the cooling water temperature drops to a predetermined recovery temperature, and to control the cooling system (20) so that the cooling water temperature is maintained at the predetermined recovery temperature for a second recovery time. [8] The fuel cell control system according to any one of the preceding claims, further comprising a start-up control unit (70) configured to determine whether or not to control the cooling system (20) by the cooling control unit (40) when shutdown of the fuel cell (10) is requested, and to control shutdown of the fuel cell (10) after control of the cooling system (20) by the cooling control unit (40) is completed. [9] A fuel cell control method comprising: Detecting (S100) a fuel cell or cooling water temperature in a cooling system when a fuel cell generates electrical power, Comparing (S400) the detected fuel cell temperature or cooling water temperature with a predetermined power drop temperature, and Controlling (S600) the cooling system to additionally cool the fuel cell when the fuel cell stops generating electric power when the measured fuel cell temperature or cooling water temperature is equal to or higher than the predetermined power drop temperature. [10] The fuel cell control method according to claim 9, further comprising monitoring the magnitude of electric power or electric current output from the fuel cell when the fuel cell generates electric power before controlling the cooling system, wherein in controlling (S600) the cooling system, the cooling system is controlled so that the fuel cell is additionally cooled when power generation stops when the monitored magnitude of electric power or electric current from the fuel cell is equal to or higher than a predetermined high-power reference or a predetermined high-current reference. [11] The fuel cell control method according to claim 10, further comprising accumulating and measuring (S200) a time during which the magnitude of the electric power or the electric current monitored after starting the fuel cell is kept equal to or higher than the predetermined high-power reference or the predetermined high-current reference after monitoring the magnitude of the electric power or the electric current, wherein in controlling (S600) the cooling system, the cooling system is controlled so that the fuel cell is additionally cooled when the power generation is stopped, when the time measured and accumulated by a time measuring unit is equal to or longer than a predetermined time. [12] The fuel cell control method according to any one of claims 9 to 11, wherein in controlling (S600) the cooling system, the cooling system is controlled to cool the fuel cell for a predetermined second recovery time after the cooling water is cooled to a predetermined recovery temperature. [13] The fuel cell control method according to claim 12, wherein in controlling (S600) the cooling system, the rotational speed of a cooling pump and / or the rotational speed of a cooling fan is controlled to a maximum level until the cooling water temperature drops to a predetermined recovery temperature, and the cooling system is controlled so that the cooling water temperature is maintained at the predetermined recovery temperature for a second recovery time. [14] The fuel cell control method according to any one of claims 9 to 13, further comprising controlling (S700) the shutdown of the fuel cell after controlling the cooling system of the cooling control unit when the shutdown control of the fuel cell is requested after controlling the cooling system.

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