CN2773709Y

CN2773709Y - Voltage inspecting and monitoring device for large-scale integrated fuel cell

Info

Publication number: CN2773709Y
Application number: CN 200420021670
Authority: CN
Inventors: 傅明竹; 胡里清
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: Shanghai Shenli Technology Co Ltd
Priority date: 2004-04-07
Filing date: 2004-04-07
Publication date: 2006-04-19
Anticipated expiration: 2014-04-07

Abstract

The utility model relates to a voltage inspecting and monitoring device which is suitable for large-scale integrated type fuel batteries. The device comprises a single battery voltage detector, a comprehensive analysis controller and an upper layer controller or an upper layer monitor of a power generation system, wherein the single battery voltage detector comprises a monolithic computer with a communication interface of a controller area bus (a CAN bus) and a plurality of photoelectric switch devices, the photoelectric switch devices are connected with a plurality of single batteries to be monitored in a one-to-one correspondence mode, the conduction or the closure of corresponding photoelectric switch devices can be controlled by output signals of the monolithic computer in an itineracy control mode and the monolithic computer can cause collected numerical values to be sent to the comprehensive analysis controller and the upper layer controller or the upper layer monitor of the power generation system through a CAN bus. The utility model has the characteristics of simple structure, reliable performance, etc.

Description

Voltage detection and monitoring device suitable for large-scale integrated fuel cell

Technical Field

The utility model relates to a fuel cell especially relates to a voltage detection and monitoring device who is fit for extensive integrated form fuel cell.

Background

An electrochemical fuel cell is a device capable of converting hydrogen and an oxidant into electrical energy and reaction products. The inner core component of the device is a Membrane Electrode (MEA), which is composed of a proton exchange Membrane and two porous conductive materials sandwiched between two surfaces of the Membrane, such as carbon paper. The membrane contains a uniform and finely dispersed catalyst, such as a platinum metal catalyst, for initiating an electrochemical reaction at the interface between the membrane and the carbon paper. The electrons generated in the electrochemical reaction process can be led out by conductive objects at two sides of the membrane electrode through an external circuit to form a current loop.

At the anode end of the membrane electrode, fuel can permeate through a porous diffusion material (carbon paper) and undergo electrochemical reaction on the surface of a catalyst to lose electrons to form positive ions, and the positive ions can pass through a proton exchange membrane through migration to reach the cathode end at the other end of the membrane electrode. At the cathode end of the membrane electrode, a gas containing an oxidant (e.g., oxygen), such as air, forms negative ions by permeating through a porous diffusion material (carbon paper) and electrochemically reacting on the surface of the catalyst to give electrons. The anions formed at the cathode end react with the positive ions transferred from the anode end to form reaction products.

In a pem fuel cell using hydrogen as the fuel and oxygen-containing air as theoxidant (or pure oxygen as the oxidant), the catalytic electrochemical reaction of the fuel hydrogen in the anode region produces hydrogen cations (or protons). The proton exchange membrane assists the migration of positive hydrogen ions from the anode region to the cathode region. In addition, the proton exchange membrane separates the hydrogen-containing fuel gas stream from the oxygen-containing gas stream so that they do not mix with each other to cause explosive reactions.

In the cathode region, oxygen gains electrons on the catalyst surface, forming negative ions, which react with the hydrogen positive ions transported from the anode region to produce water as a reaction product. In a proton exchange membrane fuel cell using hydrogen, air (oxygen), the anode reaction and the cathode reaction can be expressed by the following equations:

and (3) anode reaction:

and (3) cathode reaction:

in a typical pem fuel cell, a Membrane Electrode (MEA) is generally placed between two conductive plates, and the surface of each guide plate in contact with the MEA is die-cast, stamped, or mechanically milled to form at least one or more channels. The flow guide polar plates can be polar plates made of metal materials or polar plates made of graphite materials. The fluid pore channels and the diversion trenches on the diversion polar plates respectively guide the fuel and the oxidant into the anode area and the cathode area on two sides of the membrane electrode. In the structure of a single proton exchange membrane fuel cell, only one membrane electrode is present, and a guide plate of anode fuel and a guide plate of cathode oxidant are respectively arranged on two sides of the membrane electrode. The guide plates are usedas current collector plates and mechanical supports at two sides of the membrane electrode, and the guide grooves on the guide plates are also used as channels for fuel and oxidant to enter the surfaces of the anode and the cathode and as channels for taking away water generated in the operation process of the fuel cell.

In order to increase the total power of the whole proton exchange membrane fuel cell, two or more single cells can be connected in series to form a battery pack in a straight-stacked manner or connected in a flat-laid manner to form a battery pack. In the direct-stacking and serial-type battery pack, two surfaces of one polar plate can be provided with flow guide grooves, wherein one surface can be used as an anode flow guide surface of one membrane electrode, and the other surface can be used as a cathode flow guide surface of another adjacent membrane electrode, and the polar plate is called a bipolar plate. A series of cells are connected together in a manner to form a battery pack. The battery pack is generally fastened together into one body by a front end plate, a rear end plate and a tie rod.

A typical battery pack generally includes: (1) the fuel (such as hydrogen, methanol or hydrogen-rich gas obtained by reforming methanol, natural gas and gasoline) and the oxidant (mainly oxygen or air) are uniformly distributed in the diversion trenches of the anode surface and the cathode surface; (2) the inlet and outlet of cooling fluid (such as water) and the flow guide channel uniformly distribute the cooling fluid into the cooling channels in each battery pack, and the heat generated by the electrochemical exothermic reaction of hydrogen and oxygen in the fuel cell is absorbed and taken out of the battery pack for heat dissipation; (3) the outlets of the fuel gas and the oxidant gas and the corresponding flow guide channels can carry out liquid and vapor water generated in the fuel cell when the fuel gas and the oxidant gas aredischarged. Typically, all fuel, oxidant, and cooling fluid inlets and outlets are provided in one or both end plates of the fuel cell stack.

The proton exchange membrane fuel cell can be used as a power system of vehicles such as vehicles and ships, and can also be used as a mobile or fixed power station.

The fuel cell power generation system mainly comprises a fuel cell stack and a stack support operation system. The fuel cell power generation system for vehicle, ship power or high power of a power station is required to output tens of kilowatts, even hundreds of kilowatts. For such high power output requirements, a fuel cell stack and supporting operation system with corresponding high power output are necessary.

The engineering design and manufacture of fuel cell stack with high power output are analyzed from the aspects of technology and manufacturing cost, and generally a huge single stack method consisting of a plurality of large-area polar plates cannot be adopted, but a method for achieving the high power output requirement by integrating a plurality of small and medium power fuel cell stack modules together is adopted. Shanghai Shenli company, "a large-scale integrated fuel cell that can be modularly assembled" (patent No. 03141840.6; utility model No. 03255963.1) is an integrated fuel cell that is integrated by a number of fuel cell stack modules.

Each proton exchange membrane fuel cell stack module is generally formed by connecting a plurality of single cells in series or in parallel, and is particularly important for monitoring the working voltage of the fuel cell, particularly the working voltage of all the single cells and automatically controlling safety alarm. Because any abnormal situation of the entire fuel cell power generation system, such as overcurrent, exceeding of the normal operating temperature, etc., may indicate that some of theunit cell operating voltages are in an abnormal state. Particularly, when the electrode breaks down, the output voltage of the single cell where the electrode is located can reach abnormal values, such as being close to zero, even negative values occur, and the working output voltage of other normal single cells is generally between 1.2 and 0.5V. Electrodes that operate for long periods of time at negative values can cause permanent damage and present unsafe factors. Therefore, it is very important to monitor the single cells of each module of the fuel cell stack, and when the operating voltage of an individual or some single cells is lower than the normal operating voltage of other single cells, the control subsystem of the fuel cell power generation system should give an alarm in time, and even execute commands of stopping, cutting off load, cutting off hydrogen supply and the like.

Shanghai Shenli company 'device and method for monitoring and alarming the working voltage of each single cell of fuel cell' (invention patent No. 02136838.4; Utility model patent No. 02266891.8). The invention aims to solve the technical problem of providing a device and a method for monitoring the working voltage of a single cell and giving a safety alarm, which can directly measure the real output voltage of a single cell or a small number of single cell battery packs, provide a safety alarm for abnormal conditions and send a safety protection command to a controller.

Although the technology of this patent can monitor the output voltage of a single cell or a group of single cells in a fuel cell stack module, the technology also has some technical defects, the single chip adopted by the technology comprises an a/D converter and a plurality of switching devices, each single cell in a fuel cell stack module has at least one group of independent leading-out monitoring lines connected with the corresponding switching device and the a/D converter, and each switching device is connected with the single chip (as shown in fig. 1).

Therefore, when the fuel cell stack contains too many cells, or when it is necessary to monitor the operating voltages of all the cells in a plurality of fuel cell stack modules, the above-described technique may lead to the following situations:

1. the RS485 communication mode is adopted, so that the speed is low, and the reliability is low;

2. a large number of decoding circuits are required, the size is increased, and the method is not suitable for large-scale integrated fuel cell stacks.

3. The number of the battery monitoring lines is too large, and the lead is too long;

4. the lead is too long, so that the lead is easily subjected to external electromagnetic interference, and the communication reliability is reduced;

5. the volume is large, and the wiring is complex;

SUMMERY OF THE UTILITY MODEL

The purpose of the present invention is to provide a voltage detecting and monitoring device for large-scale integrated fuel cells, which has simple structure and reliable performance.

The purpose of the utility model can be realized through the following technical scheme: the voltage detection and monitoring device is characterized by comprising a single cell voltage detector, a comprehensive analysis controller, a power generation system upper controller or an upper monitor, wherein the single cell voltage detector comprises a single chip microcomputer with a controller area bus (CAN bus) communication interface and a plurality of photoelectric switch devices, the photoelectric switch devices are connected with a plurality of single cells to be monitored in a one-to-one correspondence manner, the photoelectric switch devices are not required to be directly connected with a decoding circuit, the single chip microcomputer outputs signals to control the conduction or the closing of the corresponding photoelectric switch devices in a circulating manner so as to further conduct or close the corresponding single cell detection circuits to be monitored, an A/D converter in the single chip microcomputer collects the output voltage of the corresponding single cells, and the collected values CAN be sent to the comprehensive analysis controller through the CAN bus, The comprehensive analysis controller, the upper layer controller or the upper layer monitor can judge whether the single cell of the fuel cell is in a normal working state or not, alarm or not and even execute a protection command of shutdown according to the received value is normal or abnormal.

One or more fuel cell voltage detectors with CAN bus communication function CAN be arranged in each fuel cell stack according to the total number of the formed single cells.

A plurality of single cell voltage detectors with CAN bus communication function CAN be combined into a large-scale CAN bus single cell voltage detection network, and the whole detection network also comprises an upper-layer controller or a monitor.

The singlechip can adopt an 87C591 singlechip.

The photoelectric switch device can adopt a photoelectric isolation relay.

The device only has two photoelectric isolation relays at specific adjacent positions to be simultaneously closed at any time, only one single cell or one group of single cell detection loop circuits are conducted each time, and the output voltage of one single cell or one group of single cells is measured.

Compared with the prior art, the utility model discloses a showing the effect and being measuring the control simply, the measured value is reliable, owing to be the direct measurement to true voltage output value, therefore false alarm signal CAN not appear, adopts CAN bus communication mode, and data transmission is reliable fast high, the large-scale integrated form group battery of specially adapted. The principle is that only two photoelectric isolation relays at specific adjacent positions are simultaneously closed at any time, the output voltage of a single cell or a group of single cells is measured, the voltage withstanding requirement of a circuit board for signal processing and digital conversion is low, and the photoelectric isolation relays are contactless, have low voltage, high conduction speed, high stability and long service life and have more advantages (see fig. 2).

The large-scale CAN bus single cell voltage detection network device is characterized in that:

1. each single cell voltage detection device is small in size and can be directly installed near the fuel cell stack module, so that the lead wires and the wiring are shortest (see fig. 4);

2. a plurality of fuel cell detection devices only need one CAN bus cable, and large lead wires are not needed.

Drawings

FIG. 1 is a schematic circuit diagram of a conventional fuel cell unit cell operating voltage monitoring and safety alarm device;

fig. 2 is a schematic circuit diagram of the cell voltage detector of the present invention;

fig. 3 is a schematic diagram of the application of the single cell voltage detector of the present invention to an integrated fuel cell;

fig. 4 is a schematic circuit structure diagram of the voltagedetecting and monitoring device of the present invention;

fig. 5 is a software programming block diagram of the present invention.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

As shown in FIG. 2, the utility model is an improved operating principle diagram of a fuel cell voltage detection device with CAN bus communication function based on the Shenli company 'device for monitoring the working voltage of each cell of the fuel cell and giving a safety alarm' (invention patent No. 02136838.4; utility model No. 02266891.8), and the device detects the total number of single cells as 28.

Fig. 3 shows an example in which an integrated fuel cell is formed by assembling two fuel cell modules, each of which is formed by two cell detector plates having a CAN bus communication function, and a total of 4 cell detector plates constitute a CAN bus detection network.

Fig. 4 is a large-scale CAN bus test network consisting of 8 cell test devices with CAN bus communication functions. In order to increase the reliability of data transmission, the detection network is additionally provided with a single cell voltage comprehensive analyzer, and the single cell voltage comprehensive analyzer transmits data to an upper controller after the data is sorted and filtered by the comprehensive analyzer so as to improve the stability and reliability of system control.

The software programming block diagram of the present invention is shown in fig. 5, and the step 100: and initially setting basic parameters in the singlechip, such as the number n of a sampling battery to be 1. Step 101: the sampling battery number is set to n +1>28, if n>28, step 102: the sampling battery number is set to n and set to zero. If n is less than 28, the step is skipped and the next step is carried out. Step 103: and setting n according to the number of the sampling battery, switching on two photoelectric relays Kn and Kn-1, and switching off all other photoelectric relays. Step 104: the voltage of the battery to be tested is connected to the single chip microcomputer for AD conversion. Step 105: and the battery voltage value after internal calculation is sent through a CAN bus interface. Returning to step 100, and repeating the steps.

Claims

1. A voltage detection and monitoring device suitable for large-scale integrated fuel cells is characterized by comprising a plurality of single cell voltage detectors, an integrated analysis controller, a power generation system upper controller or an upper monitor; the plurality of single cell voltage detectors are respectively connected with the comprehensive analysis controller through a CAN bus; the comprehensive analysis controller is connected with an upper-layer controller or an upper-layer monitor of the power generation system through a CAN bus; each single cell voltage detector comprises a single chip microcomputer with a controller area CAN bus communication interface and a plurality of photoelectric switch devices, and the plurality of photoelectric switch devices are connected with a plurality of single cells to be monitored in a one-to-one correspondence mode.

2. The voltage detecting and monitoring device suitable for large-scale integrated fuel cells according to claim 1, wherein one or more such fuel cell voltage detectors with CAN bus communication function CAN be provided for each fuel cell stack according to the total number of the formed cells.

3. The voltage detecting and monitoring device suitable for large-scale integrated fuel cells according to claim 2, wherein a plurality of cell voltage detectors having CAN bus communication function CAN be combined into a large-scale CAN bus cell voltage detection network, and the whole detection network further comprises an upper controller or monitor.

4. The voltage detection and monitoring device suitable for large-scale integrated fuel cells as claimed in claim 1, wherein the single chip microcomputer is an 87C591 single chip microcomputer.

5. The voltage detecting and monitoring device for large scale integrated fuel cell as claimed in claim 1, wherein the optoelectronic switching device is an optoelectronic isolation relay.

6. The voltage detecting and monitoring device suitable for large-scale integrated fuel cells as claimed in claim 5, wherein only two optoelectronic isolation relays in specific adjacent positions are closed at any time, and only one single cell or a group of single cell detecting loop circuits are conducted at a time.