JPH0665054B2 - Air-cooled fuel cell - Google Patents

Description

The present invention relates to temperature control of an air-cooled fuel cell.

(B) Prior Art A control method of maintaining the battery operating temperature constant (set temperature) regardless of load fluctuations is advantageous because the battery characteristics and life can be improved.

As shown in the block diagram of FIG. 1, the basic principle of the conventionally known control method is to adjust the frequency of the blower inverter according to the load amount detected by the load detection unit and set the amount of air supplied to the battery. At the same time, the damper is adjusted according to the temperature detected by the battery temperature detection unit, and the temperature of the air supplied to the battery is set so that the battery operating temperature becomes the set value.

However, with this control method, it is relatively good to maintain the battery temperature at the set value when the load fluctuation is relatively small, but it takes a considerable amount of time for the battery temperature to stabilize at the set value when the load fluctuation is large. A bow is generated. For example, the load is 1
If there is a sudden change from 00% to 50%, 50
The air volume by the blower corresponding to the% load is supplied to the battery body.

At this time, since the battery body has a large amount of heat, the reaction heat at 100% load is accumulated. Therefore, in the early stage when the load changed to 50%, the reaction heat at 100% load and 100%
Although it is necessary to radiate both of the heat storage under load, the air temperature is 50% to remove the reaction heat under load, so the battery temperature rises. For this reason, the damper is opened to increase the amount of external air introduced to lower the temperature of the air supplied to the battery body, thereby attempting to maintain the battery temperature at a set value (about 180 ° C.).

However, the supply air temperature is not infinitely lowered, and is preferably 120 ° C. or higher in order to prevent deterioration of catalytic activity due to carbon monoxide poisoning of the electrode catalyst.
The limit is 10 ° C. Therefore, in order to reduce the battery temperature that has risen transiently to the set value, it is necessary to maintain the supply air temperature at 120 ° C. or higher and gradually perform it over a long period of time. Therefore, as shown in FIG. It takes about 15 minutes to stabilize, and there is a problem that battery performance is adversely affected due to lack of quick response of battery temperature to load fluctuation.

(C) Object of the invention It is an object of the present invention to provide an air-cooled fuel cell that quickly restores the cell temperature to a set value even when the load fluctuates significantly, and that has a good responsiveness to the cell temperature.

(D) Configuration of the Invention The present invention sets the damper uniquely to adjust the supply air temperature according to the load amount, and at the same time calculates the basic frequency of the blower inverter according to the load amount and detects the basic frequency. Corrected according to the deviation between the battery temperature and the set temperature,
The temperature control of the air-cooled fuel cell is characterized in that the blower inverter is driven at this correction frequency to set the amount of air supplied by the blower.

The basic principle of such temperature control of the present invention is shown in the block diagram of FIG.

(E) Embodiment An embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a schematic view of an air-cooled fuel cell according to an example of the present invention. The air-cooled fuel cell in FIG. 4 has a fuel supply path (A) connecting a cell body (S) and a fuel supply source. )When,
Provided in the fuel supply path (A), the cell body (S)
A regulating valve (8) for regulating the flow rate of fuel supplied to the valve, and an introduction valve (7) provided upstream of the regulating valve (8),
An exhaust gas passage (B) through which the fuel exhaust gas discharged from the battery body (S) passes, a fuel exhaust gas valve (9) provided in the middle of the exhaust gas passage (B), a battery body and a battery body (S) An air supply path (C) connecting a supply source of air used for reaction and cooling, an air discharge path (D) for passing the air discharged from the battery body (S) and discharging the air to the outside, Air supply path (C)
And the air discharge path (D), a circulation branch (4), a damper (2) provided at a connecting portion between the air discharge path (D) and the circulation branch (4), and an air discharge path (D). ) And an exhaust valve (3) provided on the downstream side of the connecting portion of the air discharge path (D) and the circulation branch path (4), and an air supply path (C) in the middle of the air supply path (C). Intake valve (6) and filter (5) provided on the upstream side of the connecting portion between C) and the circulation branch (4), and in the middle of the air supply channel (C) and in circulation with the air supply channel (C). It has a blower (1) provided on the downstream side of the connection portion with the branch (4) and a load (L) connected to the battery body (S).

The blower (1) controls the amount of air supplied to the battery body (S), and the damper (2) controls the flow rate of the air discharged from the battery body (S) to the outside. The amount of fresh air suction is adjusted by changing the ratio of the flow rate to the circulation branch.

In such an air-cooled fuel cell, reaction air and air required for cooling are supplied from the air supply source to the cell body (S) by the blower (1) through the air supply passage (C). At this time, when the frequency of the blower inverter (25) is changed, the rotation amount of the motor (26) connected to the blower (1) changes the frequency of the air supplied to the battery main body (S). However, the air volume of the blower (1) changes and the supply amount also changes.

Further, a part of the air discharged from the battery body (S) is discharged to the outside through the exhaust valve (3) by the damper (2) and the remaining part enters the circulation branch (4), and the discharged air is discharged. Corresponding to the condition (1), it is returned to the battery body (S) together with the fresh air sucked from the filter (5) and the intake valve (6).

On the other hand, the fuel gas such as reformed hydrogen gas is supplied to the battery main body (S) through the introduction valve (7) and the regulating valve (8) provided in the fuel supply passage (A), and together with the oxygen in the air. After being used for electrode reaction, it is discharged from the outlet valve (9).

Amount of air supplied to the battery main body (S) by the blower (1), a flow rate of air discharged from the battery main body (S) by the damper (2) to the outside, a flow rate to a circulation branch, and fuel. The flow rate of fuel by the control valve (8) is controlled by a microcomputer (10) including a processing unit (PU), a memory (ROM) and an interface (I / O).

The interface (I / O) detects the amount of electricity supplied to the load (L) by a current detector (11) such as a shunt and the battery temperature by a temperature detector (12) such as a thermocouple. The detection signals are respectively sent to the A / D converter (13).
It is inputted as a digital signal in (14).

On the other hand, the supply air flow rate and the introduced fuel flow rate are detected as air pressures by the flow rate detectors (15) (16) such as Vito tubes, and are analog-converted by the air-electric converters (17) (18) respectively, and then A / It is inputted as a digital signal through the D converters (19) and (20).

In the memory (ROM), basic formulas for determining the fuel flow rate setting value, the damper setting value, and the basic frequency setting value of the blower inverter (25) corresponding to the load are stored in advance, and the load detector (11) outputs the basic equations. The corresponding basic equations are read from the memory (ROM) and calculated by the processing unit (PU) to determine the respective set values.

The fuel flow rate is calculated and determined by the read basic equation af (x) (f (x) is a function of load x, and a is a constant). This flow rate is the flow rate detected by the flow rate detector (16). The fuel control valve (8) is controlled while feeding back the value. At this time, the output signal from the interface (I / O) is D
The A / A converter (21) and the electropneumatic converter (22) convert the air pressure to control the fuel control valve (8).

The damper (2) uses the basic formula bf read according to the load.
(X) (b is a constant) Substitute the load value x for calculation in the processing unit (PU), and send a pulse signal from the interface (I / O) to the pulse motor (23) so as to reach the set value. Is adjusted by.

Specifically, as the load increases, the damper is adjusted to increase the flow rate of discharged air. This allows
Even if the heat of reaction increases due to the increase in load and the temperature of the battery body (S) rises, the inflow of fresh air from the outside increases, so the temperature of the supply air to the battery body (S) increases. Cooling capacity is improved.

On the contrary, when the load becomes smaller, the damper is adjusted so as to reduce the discharged flow rate ratio. As a result, when the load decreases and the reaction heat decreases, the inflow of fresh air is suppressed, so the temperature of the air supplied to the battery main body (S) rises, and the cooling capacity is suppressed.

In this way, the circulation / discharge ratio is changed according to the load amount to control the fresh air intake amount, and the temperature of the air supplied to the battery body (S) is set.

Frequency of the blower inverter (25), like the basic type cf (x) read in accordance with the load (c is a constant) defines the fundamental frequency (F _R) and calculates by. This basic frequency (F _R ) determines how much the battery temperature is relative to the set value (temperature deviation value) based on the signal input from the temperature detector (12), and corrects it according to the determination result. It is determined by

Frequency control value for correcting the fundamental frequency _{(F R)} (ΔM)
Is a PID represented by ΔM = lde / dt + me + nde ² / dt ² (A) (where, e = temperature deviation value = (battery set temperature) − (battery detection temperature) l, m, and n are constants) It is obtained by performing a control calculation.

The frequency is corrected by adding ΔM obtained from the above (A) to the fundamental frequency (F _R ).

In this way, the corrected frequency signal (F ← F _{R +} Δ
M) is input from the interface (I / O) to the inverter (25) through the D / A converter (24). The rotation of the motor (26) is controlled according to this input signal,
The blower (1) adjusts the supply air amount.

This supply air amount is controlled to a set value by inputting the flow rate value detected by the flow rate detector (15) to the interface and feeding it back as in the case of the fuel flow rate.

In the blower flow rate adjustment as described above, the specific frequency correction of the inverter is performed as follows.

If higher in the battery temperature detected from the battery set temperature is corrected in the direction in which the frequency is increased by adding the ΔM to the fundamental frequency (F _R), if conversely, the direction of the battery temperature detected from the battery set temperature lower , .DELTA.M becomes a negative value, the frequency is corrected in a decreasing direction by adding a fundamental frequency (F _R) the .DELTA.M. (Of course, if there is no temperature difference, ΔM =
It becomes 0. By performing such correction, when the battery detection temperature is higher than the battery set temperature, the amount of air supplied to the battery body (S) increases, the cooling effect increases, and the battery temperature decreases. Action will occur.

On the other hand, if the battery detection temperature is lower than the battery set temperature,
The amount of air supplied to the battery body (S) is reduced, the cooling effect is reduced, and the operation occurs in the direction of increasing the battery temperature.

In the air-cooled fuel cell of the present invention which performs such control, the cell temperature is restored to the set temperature in a short time of 2 to 3 minutes even when the load largely changes, as shown in FIG.

FIG. 5 is a flow chart for executing the above-mentioned control.
^{1 to} P ¹² indicate the steps of the flowchart. This flow is performed at a fixed cycle, for example, 10 times / sec.

When conditions of the fuel cell at P ² now starts normal operation reaches a predetermined value, enter the load and the battery temperature at P ^3, whether loading input in P ⁴ is equal to the load that is input previous To judge. However, a certain value is input in advance as the initial value (F) of the load.

If the load is not equal, setting a fuel flow rate corresponding to the load P ⁵ a (Ff), and sets the angle of the damper in accordance with the load P ^6, the fundamental frequency, further in accordance with the load P ^{7 (F R)} to calculate the. Set deviation for the set temperature of the battery temperature as input P ⁹ frequency control value for correcting the (F ^R) based on (e) a (ΔM), P
^{In 10} , the correction frequency (F ← F ^R + ΔM) is obtained by adding (F ^R ) set in P ⁷ and (ΔM) set in P ⁹
Determine.

If the loads are equal, the frequency symbol is changed from F to F at P ^8.
After transferring to ^R , the frequency is corrected based on the temperature deviation value (e) at P ⁹ and P ¹⁰ as described above.

The above result is transferred to the output register of (I / O) at P ¹¹ ,
In P ¹² Back to the next control program.

(F) Result of the Invention According to the present invention, the blower is set with the ratio of the flow rate of the air discharged from the battery main body by the damper to the outside and the flow rate to the circulation branch according to the load amount of the battery. Calculates the basic frequency of the inverter, corrects this basic frequency according to the deviation between the detected battery temperature and the set temperature, determines the inverter frequency based on this corrected frequency, and sets the blower volume by the blower. Therefore, even when the load changes significantly, the battery temperature can be quickly restored to the set value and kept constant, so that the battery can be operated under optimum conditions.

Furthermore, the ratio of the flow rate of the air discharged from the battery body to the outside by the damper and the flow rate to the circulation branch is uniquely set by the load, and the battery temperature changes the air flow of the blower and maintains the set value. As in the conventional method, the battery is cooled without excessively lowering the temperature of the air supplied to the battery, so that it is possible to provide a fuel cell with good battery characteristics and battery life, such as not causing a drop in catalytic performance. it can.

[Brief description of drawings]

1 and 2 are block diagrams showing the basic principle of temperature control in a fuel cell. FIG. 1 shows the case of the conventional temperature control, and FIG. 2 shows the case of the temperature control of the present invention. FIG. 3 is a diagram showing a comparison of the recoverability of the conventional temperature control and the temperature control of the present invention when the load changes, FIG. 4 is a system diagram of the air-cooled fuel cell of the present invention, and FIG. It is a flow chart of control of an air cooling type fuel cell. (S) Battery body, (L) Load, (1) Blower, (2) Damper, (10) Microcomputer, (11) Load detector, (12) Battery temperature detector, (15) Air flow detector, (13), (14), (19) A / D converter, (2
1), (24) D / A converter, (17) static converter,
(22) Electro-pneumatic converter, (25) Inverter.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Makoto Yamada 2-18 Keihan Hon-dori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (72) Inventor Ta Osamu 2-18-2 Keihan-hondori, Moriguchi City, Osaka Sanyo Denki Within the corporation

Claims (1)

[Claims] 1. An air supply path for connecting a battery main body with an air supply source used for battery reaction and cooling, and an air exhaust path for passing air exhaust gas discharged from the battery main body to the outside. The circulation branch that connects the air supply path and the air discharge path, and the flow rate and the circulation branch of the exhaust air discharged from the battery body, which is provided at the connecting portion between the air discharge path and the circulation branch. It is provided on the downstream side of the connection between the damper that adjusts the ratio of the flow rate to the passage and the circulation branch of the air supply passage, and adjusts the amount of air that is supplied to the battery body. The blower to be determined, the load connected to the battery body, the temperature detector that detects the temperature of the battery body, the load detector that detects the magnitude of the load connected to the battery body, and the air by the blower. Check the supply flow rate of Adjust the damper to increase the flow rate to the discharge path when the load increases and decrease the flow rate to the discharge path when the load decreases as the load increases. Based on the first control means for performing the above, the basic frequency of the blower inverter is calculated based on the load detected by the load detection means, and by the formula shown below in consideration of the battery detection temperature detected by the battery temperature detector. The correction value ΔM is calculated, and ΔM = de / dt + me + nde ² / dt ² (the above e = (set temperature) − (battery detection temperature), m,
n is a constant) The basic frequency is corrected by adding the correction value ΔM calculated by the above equation to the basic frequency. When the battery detection temperature is higher than the set temperature, the frequency is increased to increase the battery detection temperature. If the temperature is lower than the set temperature, the frequency is decreased, and the flow rate of the blower is determined based on the corrected frequency and the flow rate detected by the air flow rate detector. An air-cooled fuel cell comprising: a control unit.