Hydrogen filling method for fuel cell vehicle

A hydrogen filling method for a fuel cell vehicle includes filling a hydrogen tank of the fuel cell vehicle with hydrogen using a hydrogen dispenser by sequentially using a low-pressure storage tank of the fuel cell vehicle, a medium-pressure storage tank of the fuel cell vehicle, and a high-pressure storage tank of the fuel cell vehicle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Korean Patent Application No. 10-2016-0052223, filed on Apr. 28, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates generally to a hydrogen filling method for a fuel cell vehicle and, more particularly, to a technology for safely filling a fuel cell vehicle with the maximum amount of hydrogen fuel.

For the purposes of the present disclosure, a hydrogen tank refers to a tank provided in a fuel cell vehicle, and a storage tank refers to a tank connected to a hydrogen dispenser of a hydrogen station.

BACKGROUND

While internal combustion engine vehicles run by the rotational power of an internal combustion engine caused by the explosion occurring during the combustion of fossil fuels with oxygen from the air, fuel cell vehicles run by rotational power of an electric motor that is driven using electrical energy generated by a fuel cell stack. The fuel cell stack, which is a power source of the fuel cell vehicle, generates electrical energy through an electrochemical reaction of hydrogen supplied by a high-pressure hydrogen tank in the vehicle with oxygen from the air supplied by an air supply device.

In a fuel cell vehicle, it is important to safely store hydrogen fuel in a compact tank. To this end, various hydrogen storage techniques that meet the requirements of increased mileage and safety have been developed. For instance, a lightweight, high-strength hydrogen tank that can withstand high-pressure is generally used by filling the interior of the hydrogen tank with hydrogen. In order to secure spaces for all passengers and enough mileage, the interior of the tank may be filled with hydrogen under high-pressure.

In general, the specification of a hydrogen tank for fuel cell vehicles is 350 bar or 700 bar. A reinforcing material such as carbon fiber may be wound on the exterior of a tank main body made of metal such as an aluminum alloy, or plastic in order to ensure sufficient internal pressure resistance.

Meanwhile, the fuel cell vehicle may be filled with hydrogen from a hydrogen dispenser. For safe and quick refueling, the fuel cell vehicle may measure the pressure and temperature of the hydrogen tank and transmit the measured results to the hydrogen dispenser. Therefore, if there is a communication error between the fuel cell vehicle and the hydrogen dispenser, it becomes difficult to normally fuel the vehicle with hydrogen.

In a conventional hydrogen filling method for a fuel cell vehicle, when there is a communication error between a fuel cell vehicle and a hydrogen dispenser, the fuel cell vehicle is filled with an amount of hydrogen less than the maximum filling amount for sufficient time (e.g., at least 10 minutes) in consideration of a possible risk of explosion that may occur while fueling. Consequently, it is difficult to fuel the vehicle with the maximum amount of hydrogen quickly and safely.

For example, even when the capacity of the hydrogen tank provided in the fuel cell vehicle is 700 bar, the fuel cell vehicle sets a target filling amount to 600 bar due to the risk of explosion and is filled with hydrogen slowly. Therefore, it is difficult to fuel the vehicle with the maximum amount of hydrogen and difficult to maintain the maximum mileage.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems occurring in the related art while advantages achieved by the prior art are maintained intact.

An aspect of the present disclosure provides a hydrogen filling method for a fuel cell vehicle, characterized by filling a hydrogen tank of the fuel cell vehicle with hydrogen while sequentially using a plurality of storage tanks (e.g., hydrogen storage tanks provided in a hydrogen station) having different levels of pressure, thereby filling the hydrogen tank with the maximum amount of hydrogen fuel quickly and safely even during a communication error between a hydrogen dispenser and the fuel cell vehicle making it difficult to monitor the pressure and temperature of the hydrogen tank from the fuel cell vehicle.

The objects of the present disclosure are not limited to the foregoing objects, and any other objects and advantages not mentioned herein will be clearly understood from the following description. The present inventive concept will be more clearly understood from exemplary embodiments of the present disclosure. In addition, it will be apparent that the objects and advantages of the present disclosure can be achieved by the elements claimed in the claims and a combination thereof.

According to embodiments of the present disclosure, a hydrogen filling method for a fuel cell vehicle includes: filling a hydrogen tank of the fuel cell vehicle with hydrogen using a hydrogen dispenser by sequentially using a low-pressure storage tank of the fuel cell vehicle, a medium-pressure storage tank of the fuel cell vehicle, and a high-pressure storage tank of the fuel cell vehicle.

The filling of the hydrogen tank may include: filling the hydrogen tank using the low-pressure storage tank when there is an infrared (IR) communication error between the hydrogen dispenser and the fuel cell vehicle; filling the hydrogen tank using the medium-pressure storage tank unless hydrogen stored in the low-pressure storage tank moves to the hydrogen tank; filling the hydrogen tank using the high-pressure storage tank unless hydrogen stored in the medium-pressure storage tank moves to the hydrogen tank; and completing the filling of the hydrogen tank unless hydrogen stored in the high-pressure storage tank moves to the hydrogen tank.

The method may further include determining whether or not the hydrogen stored in any of the low-pressure storage tank, the medium-pressure storage tank, and the high-pressure storage tank moves to the hydrogen tank using a flowmeter.

While being filled with hydrogen, the fuel cell vehicle may output a warning signal when the temperature of the hydrogen tank exceeds a threshold value, thereby preventing a risk of explosion of the hydrogen tank.

The method may further include: maintaining a first reference pressure in the low-pressure storage tank through a compressor; maintaining a second reference pressure in the medium-pressure storage tank through a compressor; and/or maintaining a third reference pressure in the high-pressure storage tank through a compressor.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The above and other objects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings so that those skilled in the art to which the present disclosure pertains can easily carry out technical ideas described herein. In addition, a detailed description of well-known techniques associated with the present disclosure will be ruled out in order not to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Referring now to the presently disclosed embodiments,FIG. 1illustrates a hydrogen filling system for a fuel cell vehicle according to embodiments of the present disclosure.

As illustrated inFIG. 1, a hydrogen station may receive hydrogen from a hydrogen tube100delivered by a trailer, compress hydrogen through a compressor200, and store the compressed hydrogen in a storage tank300. The compressed hydrogen stored in the storage tank300may be fed to a fuel cell vehicle500through a hydrogen dispenser400. The storage tank300includes a low-pressure storage tank310(for example, 0-200 bar), a medium-pressure storage tank320(for example, 200-500 bar), and a high-pressure storage tank330(for example, 500-700 bar).

In addition, the compressor200may perform a compression process periodically to maintain the pressure of the low-pressure storage tank310as a reference value (e.g., 200 bar) (or “first reference pressure”), perform a compression process periodically to maintain the pressure of the medium-pressure storage tank320as a reference value (e.g., 500 bar) (or “second reference pressure”), and perform a compression process periodically to maintain the pressure of the high-pressure storage tank330as a reference value (e.g., 700 bar) (or “third reference pressure”).

Meanwhile, infrared (IR) communications may be performed between the hydrogen dispenser400and the fuel cell vehicle500, and the hydrogen dispenser400may receive the pressure and temperature of a hydrogen tank from the fuel cell vehicle500and use the pressure and temperature as parameters for safe hydrogen fueling. The hydrogen dispenser400may be provided with an IR receiver (not shown), and the fuel cell vehicle500may be provided with an IR transmitter (not shown).

In addition, the hydrogen dispenser400may be provided with a flowmeter to monitor flow rate changes. In other words, it may be determined whether or not hydrogen moves from the storage tank300to the hydrogen tank of the fuel cell vehicle500. That is, it may be determined whether or not the hydrogen tank of the fuel cell vehicle500is being filled with hydrogen.

FIG. 2illustrates a flowchart of a hydrogen filling method for a fuel cell vehicle according to embodiments of the present disclosure. The method is performed by the hydrogen dispenser400.

First, when a nozzle of the hydrogen dispenser400is connected to a receptacle of the fuel cell vehicle500in operation201, it may be determined whether or not IR communication is normally performed in operation202. In other words, it may be determined whether or not the pressure and temperature of the hydrogen tank is received from the fuel cell vehicle500through the IR communication.

As a result of the determination in operation202, when the IR communication is normally performed, the fuel cell vehicle may be filled with hydrogen on the basis of the received pressure and temperature of the hydrogen tank in operation203. Here, a well-known filling process may be used.

On the other hand, when the IR communication is not normally performed, the hydrogen dispenser400may connect the fuel cell vehicle500to the low-pressure storage tank310to try a filling process in operation204.

Next, it may be determined whether or not hydrogen stored in the low-pressure storage tank310moves to the hydrogen tank of the fuel cell vehicle500in operation205. In other words, it may be determined whether or not hydrogen stored in the low-pressure storage tank310is being fed to the hydrogen tank of the fuel cell vehicle500.

As a result of the determination in operation205, when the hydrogen tank of the fuel cell vehicle500is being filled with hydrogen, it may wait until the filling process is completed, or when the hydrogen tank of the fuel cell vehicle500is not being filled with hydrogen, the hydrogen dispenser400may disconnect the fuel cell vehicle500from the low-pressure storage tank310and connect the fuel cell vehicle500to the medium-pressure storage tank320to try a filling process in operation206.

Thereafter, it may be determined whether or not hydrogen stored in the medium-pressure storage tank320moves to the hydrogen tank of the fuel cell vehicle500in operation207. In other words, it may be determined whether or not hydrogen stored in the medium-pressure storage tank320is being fed to the hydrogen tank of the fuel cell vehicle500.

As a result of the determination in operation207, when the hydrogen tank of the fuel cell vehicle500is being filled with hydrogen, it may wait until the filling process is completed, or when the hydrogen tank of the fuel cell vehicle500is not being filled with hydrogen, the hydrogen dispenser400may disconnect the fuel cell vehicle500from the medium-pressure storage tank320and connect the fuel cell vehicle500to the high-pressure storage tank330to try a filling process in operation208.

Then, when the filling process is completed in operation209, it may end. In other words, when hydrogen stored in the high-pressure storage tank330no longer moves to the hydrogen tank of the fuel cell vehicle500, it may be determined that the filling process is completed, and the filling process may end.

In the above-described process, a hydrogen control unit (HCU) of the fuel cell vehicle500that detects an error in the IR communication may determine the temperature of the hydrogen tank periodically and output a warning signal through a cluster or a speaker in the vehicle when the temperature of the hydrogen tank exceeds a threshold value (for example, 85 degrees Celsius).

Hereinafter, the performance of a hydrogen filling method for a fuel cell vehicle according to embodiments of the present disclosure, will be detailed with reference toFIGS. 3 to 5.

FIG. 3illustrates the performance analysis of a hydrogen filling result when IR communication is available.FIG. 4illustrates the performance analysis of a hydrogen filling result when IR communication is unavailable in a conventional hydrogen filling method, andFIG. 5illustrates the performance analysis of a hydrogen filling result when IR communication is unavailable in a hydrogen filling method according to embodiments of the present disclosure.

InFIG. 3, Δt1indicates a time taken for a pressure of the hydrogen tank to reach a target pressure (e.g., 700 bar) when IR communication is available, i.e., when the hydrogen dispenser400is normally operated. In addition, Δt1also indicates a time taken for a filling amount of the hydrogen tank to reach a maximum filling amount.

InFIG. 4, Δt2indicates a time taken for a pressure of the hydrogen tank to reach a target pressure (e.g., 600 bar) when IR communication is unavailable in the conventional hydrogen filling method. In addition, Δt2also indicates a time taken for a filling amount of the hydrogen tank to reach a maximum filling amount.

InFIG. 5, Δt3indicates a time taken for a pressure of the hydrogen tank to reach a target pressure (e.g., 600 bar) when IR communication is unavailable in the hydrogen filling method according to embodiments of the present disclosure. In addition, Δt3also indicates a time taken for a filling amount of the hydrogen tank to reach a maximum filling amount.

Moreover, relationships of time (t), pressure (P), temperature (T), and a filling amount (m) may satisfy the following equation:
Δt1≈Δt3<Δt2
ΔP1=ΔP3>ΔP2
ΔT2<ΔT1≈ΔT3
Δm1=Δm3>Δm2[Equation 1]

Equation 1 may be expressed by specific values as illustrated in the following table 1 by way of example:

Alternatively, according to embodiments of the present disclosure, when the compressor200does not perform a compression process periodically in order to maintain the pressure of the low-pressure storage tank310as a reference value (e.g., 200 bar) (“first reference pressure”), does not perform a compression process periodically in order to maintain the pressure of the medium-pressure storage tank320as a reference value (e.g., 500 bar) (“second reference pressure”), and does not perform a compression process periodically in order to maintain the pressure of the high-pressure storage tank330as a reference value (e.g., 700 bar) (“third reference pressure”), an additional compressor may be provided between the storage tank300and the dispenser400. In this case, a process of filling the hydrogen tank of the fuel cell vehicle500with hydrogen will be detailed. Operations201to207may otherwise be the same in such case.

However, the additional compressor may be activated in operation208to help in filling the hydrogen tank of the fuel cell vehicle500with hydrogen. In other words, by setting a filling pressure of the compressor to a maximum filling pressure (for example, 700 bar) of the hydrogen tank of the fuel cell vehicle500, the hydrogen tank of the fuel cell vehicle500may be fully filled with hydrogen.

Meanwhile, the above-stated method according to embodiments of the present disclosure may be written as a computer program. Codes and code segments constituting the program may easily be inferred by a computer programmer skilled in the art. In addition, the written program may be stored in a computer-readable recording medium (i.e., an information storage medium) and be read and executed by a computer, thereby implementing the method according to the exemplary embodiment of the present disclosure. The recording medium includes all types of computer-readable recording media.

As set forth above, by filling the hydrogen tank of the fuel cell vehicle with hydrogen while sequentially using the plurality of storage tanks (e.g., hydrogen storage tanks provided in the hydrogen station) having different levels of pressure, the hydrogen tank of the fuel cell vehicle may be filled with the maximum amount of hydrogen fuel quickly and safely even when it is difficult to monitor the pressure and temperature of the hydrogen tank from the fuel cell vehicle due to a communication error between the hydrogen dispenser and the fuel cell vehicle.