Cooling control system and control method for fuel cell

Abstract

The present application relates to a cooling control system and a control method for a fuel cell. The cooling control system includes: a fuel cell stack, a cooling flow path is formed, hydrogen and oxygen enter the fuel cell stack and react, and a coolant flows between separators; a coolant circulation pipeline is connected to the cooling flow path of the fuel cell stack and has a coolant flowing therein; a cooling pump is connected to the coolant circulation pipeline to circulate the coolant to cool the fuel cell stack; a calorific value estimator is used to estimate the calorific value of the fuel cell stack; a coolant estimator is used to estimate the amount of coolant used to cool the fuel cell stack based on the calorific value of the fuel cell stack; and a drive controller is used to control the operation of the cooling pump based on the estimated amount of coolant.

Description

Technical Field

[0001] The present disclosure relates to a technology for estimating a heating value of a fuel cell stack and controlling a cooling pump based on the heating value of the fuel cell stack. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] The fuel cell converts chemical energy into electrical energy through an oxidation-reduction reaction using hydrogen and oxygen supplied from a hydrogen supplier and an air supplier, respectively, and includes a fuel cell stack that generates electrical energy, a cooling system that cools the fuel cell stack, and the like.

[0004] That is, hydrogen is supplied to the anode side of the fuel cell stack, and an oxidation reaction of hydrogen is performed at the anode to generate protons and electrons, and the protons and electrons generated at this time move to the cathode through the electrolyte membrane and the separator, respectively. At the cathode, water is generated by an electrochemical reaction involving protons moved from the anode, electrons, and oxygen in the air, and electrical energy is generated from the electron flow.

[0005] Thermal energy and electrical energy are generated together by chemical reactions in a fuel cell stack. The fuel cell stack includes a cooling system to prevent the fuel cell stack from overheating and deterioration due to thermal energy. Specifically, a water-cooled cooling system is mainly used, which cools the fuel cell stack by forming a cooling flow path through which a coolant flows between unit cells included in the fuel cell stack.

[0006] In this cooling system, since it is difficult to directly measure the temperature of the fuel cell stack, it can be estimated indirectly by using the outlet temperature of the coolant exhausted through the fuel cell stack. Further, according to the estimated temperature of the fuel cell stack or a pump that flows the coolant, the ratio between the coolant flowing through the radiator and the coolant bypassed by the radiator is controlled by a thermostat to control the cooling of the fuel cell stack.

[0007] That is, the fuel cell stack is cooled by mixing the coolant flowing through the radiator and the coolant bypassing the radiator flowing into the thermostat. However, we have found that when the low-temperature coolant flowing through the radiator flows into the fuel cell stack, thermal shock occurs in the fuel cell stack.

[0008] Further, we found that when the heat generated in the fuel cell stack is relatively small and the required heat dissipation is low, the radiator does not maintain the heat dissipation performance, and therefore, if the required heat dissipation of the fuel cell stack increases again, the time required for the cooling system to exert its cooling performance is delayed.

[0009] The above contents explained as background technology are only intended to help understand the background technology of the present disclosure, and are not intended to indicate that the present disclosure falls within the scope of the relevant technology known to those skilled in the art. Summary of the invention

[0010] The present disclosure provides a control system and a control method for controlling a cooling pump based on the heating value of a fuel cell stack and the coolant temperature at an inlet and an outlet of a cooling flow path of the fuel cell stack.

[0011] In one form of the present disclosure, a cooling control system for a fuel cell includes: a fuel cell stack, formed with a cooling flow path, hydrogen and oxygen flow into the cooling flow path and react, and a coolant flows between separators; a coolant circulation pipeline connected to the cooling flow path of the fuel cell stack and having a coolant flowing therein; a cooling pump connected to the coolant circulation pipeline and configured to circulate the coolant to cool the fuel cell stack; a calorific value estimator configured to estimate the calorific value of the fuel cell stack; a coolant estimator configured to estimate the amount of coolant used to cool the fuel cell stack based on the estimated calorific value of the fuel cell stack; and a drive controller configured to control the operation of the cooling pump based on the estimated amount of coolant.

[0012] In one form, the cooling control system further includes: a first temperature sensing sensor installed at an inlet of a cooling flow path of the fuel cell stack, and a second temperature sensing sensor installed at an outlet of the cooling flow path of the fuel cell stack.

[0013] The heating value estimator may estimate the heating value of the fuel cell stack by using a ratio between a theoretical voltage of the fuel cell stack and an average cell voltage and an output of the fuel cell stack.

[0014] The heating value of the fuel cell stack can be estimated by variably applying a value between a low theoretical voltage in a low heating value state and a high theoretical voltage in a high heating value state as a theoretical voltage. The theoretical voltage can be set by a heating value estimator based on the internal humidity of the fuel cell stack, the theoretical voltage can be set by the heating value estimator based on the coolant average temperature and the output value of the fuel cell stack, and the theoretical voltage can be set by a discharge cycle of condensate collected in a water trap.

[0015] The coolant estimator estimates the amount of coolant for cooling the fuel cell stack based on a heating value calculated by subtracting an air cooling amount of the air from the estimated heating value of the fuel cell stack, and the drive controller controls the operation of the fuel cell stack based on the estimated amount of coolant for cooling the fuel cell stack.

[0016] The driving controller may estimate a target value based on the amount of coolant, the specific heat of the coolant, and the coolant temperature difference between the inlet and the outlet of the cooling flow path.

[0017] The drive controller can control the cooling pump with a pre-mapped RPM determined based on the required coolant flow rate. The pre-mapped RPM can be pre-mapped based on the required coolant flow rate, the average coolant temperature, and the opening of the bypass valve of the coolant circulation line.

[0018] The drive controller may set a target value as a coolant temperature difference between an inlet and an outlet of the cooling flow path, and increase the RPM of the cooling pump when the coolant temperature difference is greater than the set target value. The target value of the coolant temperature difference may be pre-mapped based on the coolant temperature at the outlet of the cooling flow path and the heating value of the fuel cell stack.

[0019] In another form of the present disclosure, a cooling method for a fuel cell stack includes: measuring the coolant temperature at the inlet and outlet of the cooling flow path of the fuel cell stack by means of a first temperature sensing sensor installed at the inlet of the cooling flow path of the fuel cell stack and a second temperature sensing sensor installed at the outlet of the cooling flow path of the fuel cell stack; estimating the heating value of the fuel cell stack by a heating value estimator; estimating the amount of coolant used to cool the fuel cell stack based on the estimated heating value of the fuel cell stack by a coolant estimator; and controlling the operation of a cooling pump by a drive controller based on the estimated amount of coolant.

[0020] The estimating heating value may include estimating the heating value of the fuel cell stack based on a ratio between a theoretical voltage of the fuel cell stack and an average cell voltage and an output of the fuel cell stack. The heating value of the fuel cell stack may be estimated by variably applying a value between a low theoretical voltage in a low heating value state and a high theoretical voltage in a high heating value state as the theoretical voltage.

[0021] Estimating the amount of coolant to cool the fuel cell stack may include subtracting the amount of cooling in the air from the estimated heating value of the fuel cell stack.

[0022] Controlling the operation of the cooling pump may include estimating a required flow rate of the coolant by dividing the estimated amount of the coolant by a coolant specific heat of the coolant and a coolant temperature difference between an inlet and an outlet of the cooling flow path.

[0023] The controlling of the operation of the cooling pump may include setting a target value as a coolant temperature difference between an inlet and an outlet of the cooling flow path, and increasing an RPM of the cooling pump when the coolant temperature difference is greater than the set target value.

[0024] As described above, using exemplary forms of the present disclosure, control of a cooling pump may be improved based on the heating value of a fuel cell stack, thereby reducing or minimizing exposure to temporary dryness and high temperature thermal shock conditions.

[0025] The cooling pump can be controlled based on the heating value of the fuel cell stack, thereby improving cooling responsiveness and enhancing durability.

[0026] When switching from a sudden output state to the FC STOP mode, the RPM of the cooling pump can be reduced to an appropriate level compared to a conventional pump.

[0027] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order that the present disclosure may be better understood, reference will now be made to the accompanying drawings, in which various forms thereof are described by way of example, in which:

[0029] Figure 1 is a block diagram of a cooling control system for a fuel cell according to one form of the present disclosure;

[0030] Figure 2 is a flow chart showing a cooling control method of a fuel cell according to another form of the present disclosure;

[0031] Figure 3 is a graph showing the current of a fuel cell stack, the opening degree of a bypass valve of a coolant circulation line, and the RPM of a cooling pump according to cooling control of a fuel cell according to one form of the present disclosure;

[0032] Figure 4 is a graph showing the current of a fuel cell stack and the temperatures of an inlet and an outlet of a cooling flow path according to cooling control of the fuel cell according to one form of the present disclosure; and

[0033] Figure 5 is a graph showing changes in unit calorific value according to humidity according to one form of the present disclosure.

[0034] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0035] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0036] The specific structural and functional descriptions of the forms of the present disclosure disclosed in the specification or application are only for the purpose of illustrating the forms of the present disclosure, and may be embodied in various forms according to the forms of the present disclosure, and should not be interpreted as being limited to the forms set forth in the specification or application.

[0037] According to the present disclosure, various modifications and forms can be made in the form, so that specific forms are shown in the drawings and described in detail in the specification or application. However, it should be understood that it is not intended to limit the form to a specific disclosed form according to the concept of the present disclosure, but includes all modifications, equivalent forms and alternative forms that fall within the spirit and technical scope of the present disclosure.

[0038] The terms "first" and / or "second" etc. may be used to describe various components, but these components should not be limited by the terms. These terms are used to distinguish one element from another element, for example, according to the concept of the present disclosure, without departing from the claims, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

[0039] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be "directly connected" or "directly coupled" to the other element, and may be "connected" or "coupled" to the other element with other elements interposed therebetween. On the other hand, it should be understood that when stating "directly connected" or "directly coupled" to another element, any configuration element has no other elements interposed therebetween. Other expressions describing the relationship between elements, such as "between" and "directly between" or "adjacent to" and "directly adjacent to" should also be interpreted similarly.

[0040] The terms used in the specification are only for the purpose of describing a particular form and are not intended to limit the present disclosure. Unless otherwise clearly stated in the context, the singular form is also intended to include the plural form. It should be further understood that the terms "include" or "comprise" etc. specify the presence of the features, integers, steps, operations, elements, components or combinations thereof mentioned, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components or combinations thereof.

[0041] Hereinafter, the present disclosure will be described in detail by describing exemplary forms of the present disclosure with reference to the accompanying drawings. The same reference numerals shown in each of the drawings represent the same components.

[0042] The heat generation estimator, coolant estimator and drive controller according to the exemplary form of the present disclosure can be implemented by a non-volatile memory (not shown) and a processor, the non-volatile memory is configured to store data related to the algorithm configured to control the operation of various components of the vehicle, or software instructions for reproducing the algorithm, and the processor (not shown) is configured to perform the operations described below by using the data stored in the corresponding memory. Here, the memory and the processor can be implemented as separate chips. Alternatively, the memory and the processor can be implemented as a single chip integrated with each other. The processor can take the form of one or more processors.

[0043] Figure 1 is a block diagram of a cooling control system for a fuel cell according to one form of the present disclosure, Figure 2 is a flow chart of a cooling control method of a fuel cell according to another form of the present disclosure, and Figure 3 is a graph of the current of the fuel cell stack, the opening of the bypass valve of the coolant circulation line, and the RPM of the cooling pump 200 according to the cooling control of the fuel cell according to one form of the present disclosure. CTV in the graph represents the bypass valve of the coolant circulation line. Figure 4 is a graph of the current of a fuel cell stack and the temperature of the inlet and outlet of a cooling flow path according to cooling control of the fuel cell according to one form of the present disclosure. CT10 refers to the temperature measured by the first temperature sensing sensor, and CT20 refers to the temperature measured by the second temperature sensing sensor. Figure 5 It is a graph showing the change of unit calorific value according to humidity.

[0044] refer to Figures 1 to 5 According to the present disclosure, the fuel cell cooling control system includes: a fuel cell stack 100 in which hydrogen and oxygen enter and react respectively, a cooling flow path is formed, and a coolant flows between partitions; a coolant circulation pipeline 60, which is connected to the cooling flow path of the fuel cell stack 100 and has a coolant flowing therein; a cooling pump 200, which is connected to the coolant circulation pipeline 60 to circulate the coolant to cool the fuel cell stack 100; a calorific value estimator 30, which is used to estimate the calorific value of the fuel cell stack 100; a coolant estimator 40, which is used to estimate the coolant necessary amount based on the calorific value of the fuel cell stack 100 estimated by the calorific value estimator 30; and a drive controller 50, which is used to control the driving of the cooling pump 200 based on the coolant necessary amount estimated by the coolant estimator 40.

[0045] The fuel cooling control system according to the present disclosure further includes: a first temperature sensing sensor 10 installed at the inlet of the cooling flow path of the fuel cell stack 100; and a second temperature sensing sensor 20 installed at the outlet of the cooling flow path of the fuel cell stack 100.

[0046] The fuel cell stack 100, the first temperature sensing sensor 10, the second temperature sensing sensor 20, and the cooling pump 200 are connected by a coolant circulation line 60, and the fuel cell stack 100, the heat generation estimator 30, the coolant estimator 40, the drive controller 50, and the cooling pump 200 are connected by a control line. The drive controller 50 can control the RPM of the cooling pump 200.

[0047] The heating value estimator 30 may estimate the heating value of the fuel cell stack 100 by using a ratio between a theoretical voltage of the fuel cell stack 100 and an average cell voltage and an output of the fuel cell stack 100 .

[0048] The theoretical voltage is the voltage of the fuel cell stack 100 estimated by the heating value estimator 30, and the heating value of the fuel cell stack can be estimated by calculating ((theoretical voltage / cell average voltage)-1)*output / 1000.

[0049] The theoretical voltage may vary according to various factors, and the calorific value of the fuel cell stack 100 may be estimated by variably applying a value between a low theoretical voltage in a low-grade calorific value state and a high theoretical voltage in a high-grade calorific value state. Typically, the theoretical voltage between the low theoretical voltage and the high theoretical voltage is determined according to whether the generated water is condensed or contains latent heat.

[0050] Further references Figure 5 , the theoretical voltage may be set by the internal humidity of the fuel cell stack 100. When the relative humidity according to the internal humidity is 0%, the theoretical voltage is applied as a high theoretical voltage, and when the relative humidity is 100%, the theoretical voltage is applied as a low theoretical voltage. An intermediate value may be applied by performing linearization. The relative humidity value is determined according to a real-time relative humidity sensor value or a value estimated according to a relative humidity of a pre-map.

[0051] Further, the theoretical voltage may be set by the coolant average temperature and the output value. A low theoretical voltage is set as an initial value, and the theoretical voltage may be obtained by a pre-map based on the coolant average temperature and the output of the fuel cell stack 100 .

[0052] Further, the theoretical voltage may be set by the discharge cycle of the condensate collected in the water trap. For example, after the operating temperature is set to 75 degrees Celsius and the average output of the condensate discharge cycle in urban operation is set as a reference cycle, the voltage of the reference cycle may be set to a low theoretical voltage, the maximum value may be set to a high theoretical voltage, and the theoretical voltage may be applied by performing linearization according to the increase and decrease of the condensate discharge cycle.

[0053] The coolant estimator 40 estimates a required cooling amount according to the heating amount of the fuel cell stack 100 by subtracting the air cooling amount of the air from the estimated heating amount of the fuel cell stack 100 , and the driving controller 50 controls driving of the cooling pump 200 based on the estimated required cooling amount.

[0054] Since the necessary cooling amount is the sum of the required cooling amount and the air cooling amount, and the heating value of the fuel cell stack 100 is the necessary cooling amount, the required cooling amount is a value obtained by subtracting the air cooling amount from the heating value of the fuel cell stack 100 .

[0055] The air cooling amount may be formulated or considered as a constant. For example, when the air cooling amount is considered as a constant, it may be estimated to be less than 2 to 3 kW.

[0056] The drive controller 50 may estimate the required flow rate of the coolant by calculating the required cooling amount calculated by the coolant estimator 40 with the specific heat of the coolant and the target value of the coolant temperature difference between the inlet and the outlet of the cooling flow path.

[0057] The specific heat is a value obtained by multiplying the average value of the temperatures of the coolant at the outlet and the inlet of the cooling flow path sensed by the temperature sensing sensor by 0.0052 and 2.872.

[0058] The cooling pump 200 may be controlled at a pre-mapped RPM according to the required coolant flow rate. The pre-mapped RPM may be pre-mapped (pre-configured) according to the required coolant flow rate, the average coolant temperature, and the opening of the bypass valve of the coolant circulation line.

[0059] For example, the RPM value of the cooling pump 200 may be calculated by C0+C1*opening degree of bypass valve of coolant circulation line-C2*coolant average temperature+C3*coolant required flow rate, and C0 to C3 may be set as constants.

[0060] Control of the cooling pump 200 may be improved based on the heating value of the fuel cell stack 100 to reduce or minimize exposure to temporary drying and high-temperature thermal shock conditions, thereby improving cooling responsiveness and enhancing durability.

[0061] Further references Figure 3 , the amount of change in the RPM of the cooling pump 200 can be determined according to the current of the fuel cell stack and the opening degree of the bypass valve of the coolant circulation pipeline.

[0062] The drive controller 50 may set a target value as a coolant temperature difference between an inlet and an outlet of the cooling flow path, and if the coolant temperature difference is greater than the set target value, increase the RPM of the cooling pump. The target value of the coolant temperature difference may be pre-mapped according to the coolant temperature at the outlet of the cooling flow path and the heating value of the fuel cell stack 100.

[0063] As the coolant temperature at the outlet of the cooling flow path increases or the heating value of the fuel cell stack 100 increases, the pre-mapped target value of the coolant temperature difference decreases. When the coolant temperature at the outlet of the cooling flow path is constant, the target value of the coolant temperature difference is pre-mapped to decrease as the heating value of the fuel cell stack 100 increases; further, when the heating value of the fuel cell stack 100 is constant, the target value of the coolant temperature difference is pre-mapped to decrease as the coolant temperature at the outlet of the cooling flow path increases. If the coolant temperature at the outlet of the cooling flow path and the heating value of the fuel cell stack 100 increase at the same time, the target value of the coolant temperature difference is pre-mapped to decrease.

[0064] For example, in the urban operation range or heating range of the fuel cell stack 100, the required amount of coolant is relatively reduced and the RPM of the cooling pump 200 is reduced by applying an increased target value of the coolant temperature difference, and in the high output continuous range or high temperature operation range, the required amount of coolant is relatively increased and the RPM of the cooling pump 200 is increased by applying a decreased target value of the coolant temperature difference.

[0065] Further references Figure 4 , the change between the current of the fuel cell stack 100 and the coolant temperature at the inlet and outlet of the cooling flow path can be determined.

[0066] Further references Figure 2 , the fuel cell cooling control method according to the present disclosure includes: measuring the coolant temperature at the inlet and outlet of the cooling flow path by means of a first temperature sensing sensor 10 installed at the inlet of the cooling flow path of the fuel cell 100 and a second temperature sensing sensor 20 installed at the outlet of the cooling flow path of the fuel cell stack 100 (operation S10); estimating the calorific value of the fuel cell stack 100 (operation S12); estimating the required amount of coolant based on the calorific value of the fuel cell stack 100 estimated in the estimation of the calorific value (operation S12) (operation S13); and controlling the driving of the cooling pump 200 based on the required amount of coolant estimated in the estimation of the coolant (operation S14);

[0067] The estimation of the heat amount (operation S12) may estimate the heat amount of the fuel cell stack 100 by using a ratio between a theoretical voltage of the fuel cell stack 100 and an average cell voltage and an output of the fuel cell stack 100. The heat amount of the fuel cell stack may be estimated by variably applying a value between a low theoretical voltage in a low heat amount state and a high theoretical voltage in a high heat amount state as the theoretical voltage.

[0068] The estimation of the coolant (operation S13) estimates the required cooling amount according to the heating value of the fuel cell stack 100 by subtracting the air cooling amount of the air from the estimated heating value of the fuel cell stack 100, and the drive control (operation S14) can control the drive of the cooling pump 200 based on the estimated required cooling amount.

[0069] The driving control (operation S14) can estimate the required flow rate of the coolant by dividing the required cooling amount estimated in the estimation of the coolant (operation S13) by the specific heat of the coolant and the coolant temperature difference between the inlet and outlet of the cooling flow path. The driving control (operation S14) can control the cooling pump 200 by the pre-mapped RPM according to the required flow rate of the coolant.

[0070] The control of the drive (operation S14) may set a target value as a coolant temperature difference between an inlet and an outlet of the cooling flow path (operation S15), and if the coolant temperature difference is greater than the set target value (operation S20) (operation S21), the RPM of the cooling pump 200 may be increased. The target value of the coolant temperature difference may be pre-mapped according to the coolant temperature at the outlet of the cooling flow path and the heating value of the fuel cell stack 100.

[0071] Although the present disclosure has been illustrated and described with respect to a particular form, it will be understood by those skilled in the art that various improvements and changes may be made to the present disclosure within the scope of the technical spirit of the present disclosure.

Claims

1. A cooling control system for a fuel cell, comprising: A fuel cell stack is formed with a cooling flow path, hydrogen and oxygen enter the fuel cell stack and react, and a coolant flows between separators; a coolant circulation pipeline connected to the cooling flow path of the fuel cell stack and having the coolant flowing therein; a cooling pump connected to the coolant circulation line and configured to circulate the coolant to cool the fuel cell stack; a heating value estimator configured to estimate the heating value of the fuel cell stack; a coolant estimator configured to estimate an amount of coolant for cooling the fuel cell stack based on the estimated heating value of the fuel cell stack; as well as a drive controller configured to control operation of the cooling pump based on the estimated amount of coolant; wherein the calorific value estimator is configured to estimate the calorific value of the fuel cell stack based on a ratio between a theoretical voltage of the fuel cell stack and an average cell voltage and an output of the fuel cell stack, wherein the heating value of the fuel cell stack is estimated by variably applying a value between a low theoretical voltage in a low heating value state and a high theoretical voltage in a high heating value state as the theoretical voltage, The theoretical voltage is set by the heating value estimator based on any one of the following: internal humidity of the fuel cell stack, average coolant temperature and output value of the fuel cell stack, and a discharge period of condensate collected in a water trap.

2. The cooling control system according to claim 1, further comprising: a first temperature sensing sensor mounted at an inlet of the cooling flow path of the fuel cell stack; as well as A second temperature sensing sensor is installed at an outlet of the cooling flow path of the fuel cell stack.

3. The cooling control system according to claim 1, in, The coolant estimator is configured to estimate an amount of coolant for cooling the fuel cell stack based on a heating value calculated by subtracting an air cooling amount of air from an estimated heating value of the fuel cell stack, and The drive controller is configured to control the operation of the cooling pump based on an estimated amount of coolant for cooling the fuel cell stack.

4. The cooling control system according to claim 3, in, The drive controller is configured to estimate a required flow rate of coolant based on the amount of coolant estimated by the coolant estimator, the coolant specific heat, and a target value of a coolant temperature difference between an inlet and an outlet of the cooling flow path.

5. The cooling control system according to claim 4, in, The drive controller is configured to control the cooling pump at a pre-mapped rpm determined based on a desired flow rate of the coolant.

6. The cooling control system according to claim 5, in, The pre-mapped rpm is pre-mapped based on a required flow rate of the coolant, an average temperature of the coolant, and an opening degree of a bypass valve of the coolant circulation line.

7. The cooling control system according to claim 1, in, The drive controller is configured to: The target value is set as the coolant temperature difference between the inlet and the outlet of the cooling flow path, and When the coolant temperature difference is greater than a set target value, the revolutions per minute of the cooling pump are increased.

8. The cooling control system according to claim 7, in, The target value of the coolant temperature difference is pre-mapped based on the coolant temperature at the outlet of the cooling flow path and the heating value of the fuel cell stack.

9. A cooling control method for a fuel cell, the cooling control method comprising the following steps: measuring a coolant temperature at an inlet and a coolant temperature at an outlet of a cooling flow path of a fuel cell stack by a first temperature sensing sensor installed at an inlet of the cooling flow path and a second temperature sensing sensor installed at an outlet of the cooling flow path of the fuel cell stack; estimating the heating value of the fuel cell stack by a heating value estimator; estimating, by a coolant estimator, an amount of coolant for cooling the fuel cell stack based on the estimated heating value of the fuel cell stack; as well as controlling, by a drive controller, operation of a cooling pump based on the estimated amount of coolant; Wherein, estimating the heat generation includes: estimating a heating value of the fuel cell stack based on a ratio between a theoretical voltage of the fuel cell stack and an average cell voltage and an output of the fuel cell stack, wherein the heating value of the fuel cell stack is estimated by variably applying a value between a low theoretical voltage in a low heating value state and a high theoretical voltage in a high heating value state as the theoretical voltage, The theoretical voltage is set by the heating value estimator based on any one of the following: internal humidity of the fuel cell stack, average coolant temperature and output value of the fuel cell stack, and a discharge period of condensate collected in a water trap.

10. The cooling control method according to claim 9, in, Estimating the amount of the coolant used to cool the fuel cell stack includes: An air cooling amount of the air is subtracted from the estimated heating value of the fuel cell stack.

11. The cooling control method according to claim 10, in, Controlling the operation of the cooling pump includes: The required flow rate of the coolant is estimated by dividing the estimated amount of the coolant by the coolant specific heat of the coolant and the coolant temperature difference between the inlet and the outlet of the cooling flow path.

12. The cooling control method according to claim 9, in, Controlling the operation of the cooling pump includes: setting a target value as a coolant temperature difference between an inlet and an outlet of the cooling flow path, and When the coolant temperature difference is greater than a set target value, the revolutions per minute of the cooling pump are increased.

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