JP-7857130-B2 - Fuel cell system
Inventors
- 佐々木 雅也
- 樋口 和宏
Assignees
- 大阪瓦斯株式会社
Dates
- Publication Date
- 20260512
- Application Date
- 20220325
Claims (4)
- A fuel cell system comprising: a cell stack in which a plurality of battery cells are stacked, each having an electrolyte layer that conducts ions, an anode disposed on one side of the electrolyte layer, and a cathode disposed on the other side of the electrolyte layer; an anode gas supply channel for supplying anode gas to the anode chamber of the cell stack; a cathode gas supply channel for supplying cathode gas to the cathode chamber of the cell stack; an anode gas supply means for supplying anode gas; and a controller for controlling the anode gas supply means, The anode gas supply channel includes a first anode gas supply channel that supplies anode gas to the central portion of the cell stack in the stacking direction, and a second anode gas supply channel that supplies anode gas to both end portions of the cell stack in the stacking direction, and a temperature sensing means is provided in the central portion of the cell stack or its vicinity where a high temperature tendency occurs during the electrochemical reaction, or on the anode inlet side of the battery cell in the central portion. A fuel cell system characterized in that, when the temperature detected by the temperature detection means exceeds a predetermined temperature threshold, the controller increases the supply flow rate of anode gas supplied through the first anode gas supply channel, while decreasing the supply flow rate of anode gas supplied through the second anode gas supply channel, without changing the total supply flow rate of anode gas supplied to the entire cell stack.
- The fuel cell system according to claim 1, wherein the anode gas supply means includes a first anode gas supply means disposed in the first anode gas supply channel and a second anode gas supply means disposed in the second anode gas supply channel, and when the temperature of the central portion of the cell stack rises, the controller increases the rotation speed of the first anode gas supply means while decreasing the rotation speed of the second anode gas supply means, without changing the total supply flow rate of anode gas supplied to the entire cell stack.
- The fuel cell system according to claim 1 or 2, characterized in that, in relation to the cell stack, an accumulation timing means is provided for timing the cumulative operating time from the start of operation after installation, and when the accumulation timing means has timed a predetermined cumulative period, the controller increases the supply flow rate of anode gas supplied through the first anode gas supply channel while decreasing the supply flow rate of anode gas supplied through the second anode gas supply channel, without changing the total supply flow rate of anode gas supplied to the entire cell stack.
- A fuel cell system comprising: a cell stack in which a plurality of battery cells are stacked, each having an electrolyte layer that conducts ions, an anode disposed on one side of the electrolyte layer, and a cathode disposed on the other side of the electrolyte layer; an anode gas supply channel for supplying anode gas to the anode chamber of the cell stack; a cathode gas supply channel for supplying cathode gas to the cathode chamber of the cell stack; an anode gas supply means for supplying anode gas; and a controller for controlling the anode gas supply means, The anode gas supply channel includes a first anode gas supply channel that supplies anode gas to the central portion of the cell stack in the stacking direction, and a second anode gas supply channel that supplies anode gas to both end portions of the cell stack in the stacking direction. A fuel cell system characterized in that, in relation to the cell stack, a voltage measuring means is provided for measuring the generated voltage of the battery cells in the central part of the cell stack, and in a fuel depletion detection mode for detecting the fuel depletion state of the battery cells, the supply flow rate of anode gas supplied through the first anode gas supply channel is temporarily increased, and when the comparison voltage difference between the measured voltage rise value and the reference voltage rise value of the voltage measured by the voltage measuring means at this time exceeds a predetermined voltage threshold, the controller increases the supply flow rate of anode gas supplied through the first anode gas supply channel while decreasing the supply flow rate of anode gas supplied through the second anode gas supply channel, without changing the total supply flow rate of anode gas supplied to the entire cell stack.
Description
This invention relates to a fuel cell system comprising a cell stack in which battery cells are stacked. A known fuel cell system comprises a cell stack in which flat-plate-shaped battery cells are stacked, an anode gas supply channel for supplying anode gas (fuel gas) to the anode chamber of the cell stack, a cathode gas supply channel for supplying cathode gas (oxidizer gas) to the cathode gas chamber of the cell stack, an anode gas supply means for supplying anode gas, and a cathode gas supply means for supplying cathode gas. In such a fuel cell system, it is necessary to maintain the fuel utilization rate in the cell stack within a certain range. If operation continues with an excessively high fuel utilization rate (a so-called anode gas shortage), the battery cells will be damaged, making it difficult to continue power generation. In a cell stack consisting of multiple flat battery cells stacked together, a temperature distribution develops along the stacking direction (i.e., the thickness direction). Heat tends to accumulate more easily in the central part of the stack (the so-called middle layer), and the temperature in this central part tends to be higher than in the outer ends (the so-called end layers). Furthermore, generally speaking, fuel cell systems degrade over time, increasing the resistance of the battery cells. This increased resistance tends to lead to increased heat generation in those areas. In particular, the central part of the cell stack, where temperatures are higher, degrades more rapidly, resulting in even higher temperatures compared to the outer edges. In this cell stack, which consists of stacked flat battery cells, the anode gas supplied through the anode gas supply channel is initially configured to be evenly distributed to multiple battery cells. However, as the viscosity of the anode gas increases with temperature, leading to greater pressure loss, the temperature distribution of the cell stack changes over time. This change in temperature distribution affects the pressure loss at the inlet of the anode chamber in each battery cell, and this fluctuation in pressure loss alters the amount of anode gas distributed to each battery cell. For example, in the high-temperature areas of the cell stack (the central areas), the pressure drop at the anode chamber inlet increases. This reduces the distribution flow rate of anode gas to the anode chamber, leading to a shortage of anode gas supply (so-called fuel depletion). If this shortage of anode gas supply continues, the battery cell will be damaged. For these reasons, fuel cell systems have been proposed to address the issue of anode gas supply shortages in the cell stack. For example, some systems measure the resistance of each battery cell to determine the fuel utilization rate and prevent anode gas supply shortages based on this rate (see, for example, Patent Document 1); others use the output current-fuel utilization rate data of the cell stack to adjust the anode gas supply flow rate so that the fuel utilization rate falls below a predetermined value (see, for example, Patent Document 2); and still others use the voltage change rate and resistance change rate of the cell stack as indicators to detect anode gas supply shortages (fuel depletion) and adjust the anode gas supply flow rate or the power output of the cell stack to prevent damage to the cell stack (see, for example, Patent Document 3). Japanese Patent Publication No. 2009-110666Japanese Patent Publication No. 2006-59550Japanese Patent Publication No. 2008-103198 A simplified overall diagram showing a first embodiment of a fuel cell system according to the present invention.A simplified perspective view showing the cell stack of the fuel cell system in Figure 1.A simplified cross-sectional view of the cell stack in Figure 2.A simplified block diagram showing the control system of the fuel cell system in Figure 1.A flowchart showing the control flow by the control system in Figure 4.A simplified block diagram showing the control system in a second embodiment of the fuel cell system according to the present invention.A flowchart showing the control flow by the control system in Figure 6.A simplified block diagram showing the control system in a third embodiment of the fuel cell system according to the present invention.A diagram showing the relationship between the fuel utilization rate of a battery cell and the output voltage of the battery cell.A flowchart showing the control flow by the control system in Figure 8. The following describes various embodiments of the fuel cell system according to the present invention, with reference to the attached drawings. [First Embodiment of a Fuel Cell System] First, a first embodiment of a fuel cell system according to the present invention will be described with reference to Figures 1 to 5. In Figure 1, the fuel cell system of the first embodiment includes a cell stack 2 that generates electricity by an electrochemical reaction