Relay device, control method thereof, and power storage system and solar power generation system using the same

Abstract

To provide a small, lightweight, and low-cost relay device for connecting a power generation device such as a solar cell module (solar power generation panel) and a power conversion device (e.g., a power conditioner), a control method thereof, and a power storage system and a solar power generation system using the same.SOLUTION: A relay device 100 arranged between a solar cell portion 120 and a power conversion device 130 includes: a first terminal block 102 to which the solar cell portion is connected; a second terminal block 104 to which the power conversion device is connected; a relay 110 that is connected to the first terminal block and the second terminal block and connects or disconnects the solar cell portion and the power conversion device according to the output of the solar cell portion; a temperature detection portion that is provided in at least one of the first terminal block and the second terminal block; and a control portion 108 that outputs, to the relay, a signal for cutting off the connection between the solar cell portion and the power conversion device according to the output of the temperature detection portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a relay device, a control method thereof, and a power storage system and a solar power generation system using the same. [Background technology]

[0002] In photovoltaic power generation systems, a PID (potential induced degradation) phenomenon is known, in which a solar cell module (photovoltaic power generation panel) deteriorates and its output decreases. The main cause of this phenomenon is that even when the solar cell module is not operating (i.e., not generating power), such as at night, the power conditioner (i.e., a built-in DC / DC converter, etc.) is operating, and the voltage of the power conditioner is applied to the solar cell module. As a countermeasure against the PID phenomenon, Patent Document 1 below proposes providing a relay box containing multiple relays that connect or disconnect multiple solar cell modules and the power conditioner between them, and disconnecting both when the solar cell modules are not generating power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-103209 Summary of the Invention [Problem to be solved by the invention]

[0004] Terminal blocks are used to connect the relays contained in the relay box to the solar cell module and power conditioner. A direct current (e.g., 10A) flows continuously between the solar cell module and power conditioner via each relay. Therefore, if the tightening torque of the screws in the terminal block is insufficient, the contact resistance will increase, generating heat, causing the relay to become too hot, which can cause deformation or damage.

[0005] One possible solution to this problem is to replace one of the terminal blocks with a switch with a temperature protection function. However, in this case, it is not possible to detect heat generation due to insufficient screw tightening on the other terminal block. Alternatively, both terminal blocks could be replaced with switches with temperature protection functions. This would suppress heat generation due to insufficient screw tightening and improve safety. However, using a switch increases the size and weight of the connection. This reduces workability during system installation, etc., and also increases costs.

[0006] Therefore, an object of the present disclosure is to provide a small, lightweight, and low-cost relay device for connecting a power generation device such as a solar cell module (photovoltaic power generation panel) to a power conversion device (e.g., a power conditioner), a control method thereof, and a power storage system and a photovoltaic power generation system using the same. [Means for solving the problem]

[0007] A relay device according to one aspect of the present disclosure is a relay device arranged between a solar power generation panel and a power conversion device, and includes: a first terminal block to which the solar power generation panel is connected; a second terminal block to which the power conversion device is connected; a relay connected to the first terminal block and the second terminal block and connecting or disconnecting the solar power generation panel and the power conversion device depending on the output of the solar power generation panel; a temperature detection unit provided in at least one of the first terminal block and the second terminal block; and a control unit that outputs a signal to the relay to disconnect the connection between the solar power generation panel and the power conversion device depending on the output of the temperature detection unit.

[0008] A relay device according to another aspect of the present disclosure includes a first terminal block to which a solar power generation panel is connected, a power conversion device that converts power from the solar power generation panel, a relay electrically connected to the first terminal block and that connects or disconnects the solar power generation panel and the power conversion device depending on the output of the solar power generation panel, a temperature detection unit provided in the first terminal block, and a control unit that outputs a signal to the relay to disconnect the connection between the solar power generation panel and the power conversion device depending on the output of the temperature detection unit.

[0009] A power storage system according to yet another aspect of the present disclosure includes any one of the relay devices described above, a power conversion device, and a storage battery connected to an output section of the power conversion device.

[0010] A solar power generation system according to yet another aspect of the present disclosure includes any of the relay devices described above, a solar power generation panel, a power conversion device, and a storage battery connected to an output section of the power conversion device.

[0011] A control method according to yet another aspect of the present disclosure is a control method for a relay device including a first terminal block to which a solar power generation panel is connected, a second terminal block to which a power conversion device that converts power from the solar power generation panel is connected, and a relay connected to the first terminal block and the second terminal block and connecting or disconnecting the solar power generation panel and the power conversion device depending on the output of the solar power generation panel, the control method including a first step of detecting the occurrence of a temperature rise that exceeds a predetermined temperature in at least one of the first terminal block and the second terminal block, and a second step of causing the relay to disconnect the connection between the solar power generation panel and the power conversion device depending on the detection result in the first step. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a small, lightweight, and low-cost relay device for connecting a power generation device such as a solar cell module (photovoltaic power generation panel) to a power conversion device, a control method thereof, and a power storage system and a photovoltaic power generation system using the same. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram illustrating a schematic configuration of a relay device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a two-side view (i.e., a plan view and a front view) showing the configuration of the first terminal block that constitutes the relay device shown in FIG. [Figure 3] FIG. 3 is a plan view showing the configuration of a second terminal block that constitutes the relay device shown in FIG. [Figure 4]FIG. 4 is a circuit diagram showing an example of a control unit constituting the relay device shown in FIG. [Figure 5] FIG. 5 is a circuit diagram different from that of FIG. 4, showing an example of a control unit constituting the relay device shown in FIG. [Figure 6] FIG. 6 is a block diagram showing an example of a specific configuration of the relay device shown in FIG. [Figure 7] FIG. 7 is a block diagram showing a configuration for controlling the relays shown in FIG. [Figure 8] FIG. 8 is a block diagram showing an arrangement position of the switch that prevents the relay from turning on, which is different from that shown in FIG. [Figure 9] FIG. 9 is a block diagram showing a schematic configuration of a power storage system including the relay device shown in FIG. [Figure 10] FIG. 10 is a block diagram showing a power storage device according to a modified example. [Figure 11] FIG. 11 is a block diagram showing a schematic configuration of a solar power generation system including the relay device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Description of the embodiments of the present disclosure] The contents of the embodiments of the present disclosure will be listed and explained below. At least some of the embodiments described below may be combined in any combination.

[0015] (1) A relay device according to a first aspect of the present disclosure is a relay device disposed between a photovoltaic panel and a power conversion device, and includes: a first terminal block to which the photovoltaic panel is connected; a second terminal block to which the power conversion device is connected; a relay connected to the first and second terminal blocks and connecting or disconnecting the photovoltaic panel and the power conversion device in accordance with the output of the photovoltaic panel; a temperature detector provided in at least one of the first and second terminal blocks; and a control unit that outputs a signal to the relay to disconnect the photovoltaic panel and the power conversion device in accordance with the output of the temperature detector. This allows for detection of overheating if a screw in the terminal block is not tight enough during installation, repair, or maintenance (e.g., part replacement) of a system including the photovoltaic panel and the power conversion device. If an abnormal temperature occurs, the power supply from the photovoltaic panel can be quickly cut off. This prevents damage (e.g., deformation, deterioration, and damage to the terminal block) and fires.

[0016] (2) The temperature detection unit can be provided on both the first terminal block and the second terminal block, which can detect heat generated by insufficient tightening of the screws in the first terminal block and the second terminal block, and can prevent the first terminal block and the second terminal block from becoming too hot, deforming, deteriorating, or being damaged.

[0017] (3) A relay device according to a second aspect of the present disclosure includes a first terminal block to which a solar panel is connected, a power conversion device that converts power from the solar panel, a relay electrically connected to the first terminal block and connecting or disconnecting the solar panel and the power conversion device in accordance with the output of the solar panel, a temperature detection unit provided in the first terminal block, and a control unit that outputs a signal to the relay to disconnect the solar panel and the power conversion device in accordance with the output of the temperature detection unit. This makes it possible to detect overheating if a screw in the terminal block is not tight enough during installation, repair, or maintenance of a system including the solar panel and the power conversion device. If an abnormal temperature occurs, the power supply from the solar panel can be quickly cut off. This prevents damage to the terminal block and the occurrence of fires, etc.

[0018] (4) The temperature detection unit may include a thermal fuse, and the control unit may output a signal when the thermal fuse is blown. This ensures that if the terminal block generates heat and reaches an abnormal temperature, the solar panel and the power conversion device are securely disconnected, and the blown thermal fuse maintains the disconnected state, ensuring safety.

[0019] (5) The relay device may further include a switch that prevents the relay from turning on. This prevents the generated power from being supplied to the power conversion device, etc., even if the solar panel generates power during installation, repair, or maintenance of a system including the solar panel. This allows for safe work.

[0020] (6) The temperature detection unit may include a thermal fuse, and the switch may be connected in series with the thermal fuse. This allows the same state as when the thermal fuse is blown to be reproduced by turning off the switch during installation, repair, or maintenance of a system including a solar panel. This makes it easy to create a safe working environment.

[0021] (7) The relay is connected to the negative output terminal of the solar panel via the first terminal block, which effectively suppresses the PID phenomenon in the solar panel.

[0022] (8) The relay device may include N relays, where N is an integer of 2 or greater. The first terminal block may have N or more first terminals to which output units of the solar panels are connected and N or more second terminals connected to the first terminals. Each of the N relays may be connected to a corresponding second terminal. The control unit may output signals to the N relays in accordance with the output of the temperature detection unit. This allows for compatibility with systems including multiple solar panels and allows for detection of heat generation due to insufficient tightening of screws in the terminal block. As a result, if an abnormal temperature occurs, the connection between the solar panels and the power conversion device can be quickly cut off.

[0023] (9) The relay device may be provided in a power storage device including a power conversion device and a storage battery. This allows the relay device and the power conversion device to be reliably connected in a factory, etc. This prevents insufficient tightening of the screws on the terminal block, which can cause heat generation.

[0024] (10) A power storage system according to a third aspect of the present disclosure includes any one of the relay devices described above, a power conversion device, and a storage battery connected to an output section of the power conversion device. This makes it possible to detect if a screw in the terminal block is not tight enough during installation, repair, or maintenance of the power storage system. If an abnormal temperature occurs, power transmission and reception between the power storage device and the outside can be quickly cut off. This makes it possible to prevent damage to the terminal block and the occurrence of fires, etc.

[0025] (11) A photovoltaic power generation system according to a fourth aspect of the present disclosure includes any one of the relay devices described above, a photovoltaic power generation panel, a power conversion device, and a storage battery connected to an output section of the power conversion device. This makes it possible to detect if a screw in the terminal block is not tight enough during installation, repair, or maintenance of the photovoltaic power generation system. If an abnormal temperature occurs, the connection between the photovoltaic power generation panel and the power conversion device can be quickly cut off. This makes it possible to prevent damage to the terminal block and the occurrence of fires, etc.

[0026] (12) A control method according to a fifth aspect of the present disclosure is a control method for a relay device including a first terminal block to which a solar power generation panel is connected, a second terminal block to which a power conversion device that converts power from the solar power generation panel is connected, and a relay connected to the first terminal block and the second terminal block and connecting or disconnecting the solar power generation panel and the power conversion device according to the output of the solar power generation panel. The control method includes a first step of detecting a temperature rise in at least one of the first terminal block and the second terminal block that exceeds a predetermined temperature, and a second step of causing the relay to disconnect the solar power generation panel and the power conversion device according to the detection result of the first step. As a result, if a screw in the terminal block is not tight enough during installation, repair, or maintenance of a system including the solar power generation panel and the power conversion device, heat generated by the insufficient tightening can be detected. If the temperature exceeds the predetermined temperature, the connection between the solar power generation panel and the power conversion device can be quickly disconnected. Therefore, damage to the terminal block and the occurrence of a fire, etc. can be prevented.

[0027] [Details of the embodiments of the present disclosure] In the following embodiments, the same components are denoted by the same reference numerals, and their names and functions are also the same, so detailed descriptions thereof will not be repeated.

[0028] (composition) Referring to FIG. 1, a relay device 100 according to an embodiment of the present disclosure includes a first terminal block 102, a second terminal block 104, a relay unit 106, and a control unit 108. The relay unit 106 includes relays 110A-110D. The relays 110A-110D are, for example, electromagnetic relays with relatively large current capacities. The first terminal block 102 connects the output units of the multiple solar cell modules constituting the solar cell unit 120, i.e., PV (Photo Voltage) modules 122A-122D, to the relays constituting the relay unit 106 via electrical wiring (hereinafter simply referred to as wiring). Each of the PV modules 122A-122D is formed by arranging multiple solar cell cells (hereinafter simply referred to as cells) connected in series on a plane and sealing them with tempered glass or the like. Each of the PV modules 122A-122D includes one or multiple solar power generation panels, and the multiple solar power generation panels may be arranged, for example, in an array to form a PV module. The number of cells included in each of the PV modules 122A to 122D may be the same or different.

[0029] The second terminal block 104 connects each relay constituting the relay unit 106 to an input unit of the power conversion device 130 via wiring. The power conversion device 130 is, for example, a power conditioner. Note that a storage battery or the like may be connected to the power conversion device 130. When a signal indicating a temperature equal to or higher than a predetermined temperature (hereinafter referred to as an abnormal temperature) is input from at least one of the first terminal block 102 and the second terminal block 104, the control unit 108 outputs a signal to turn off (open) the relays 110A to 110D.

[0030] 1, the wiring shown by a single solid line connecting each part is for transmitting DC power, and actually represents two wirings. Therefore, each of the relays 110A to 110D represents two relays, as will be described later as a specific configuration (see FIG. 6).

[0031] Each of the first terminal block 102 and the second terminal block 104 includes a plurality of terminals to which wiring is connected. Referring to FIG. 2, the first terminal block 102 includes a base member 140 formed of an insulating material such as resin, conductive members 142 formed of, for example, copper, brass, or the like, which connect corresponding terminals, and metal (for example, iron, stainless steel, or the like) washers 144 and screws 146 constituting each terminal. Partition walls 148 are formed on both sides of each terminal. At each terminal, the wiring and the conductive member 142 are connected by sandwiching an end of the wiring (for example, a crimp terminal) between the washer 144 and the conductive member 142 and tightening the screw 146. For example, the plurality of terminals included in the first terminal unit 160 are connected to output units of the PV modules 122A-122D, and the plurality of terminals included in the second terminal unit 162 are connected to one terminal of the relays 110A-110D via wiring. 2, eight terminals are shown in each of the first terminal unit 160 and the second terminal unit 162 in correspondence with a total of eight wires (corresponding to the four solid lines in FIG. 1) connected to a total of four output units of the PV modules 122A to 122D, but this is not limitative. The number of PV modules constituting the solar cell unit 120 is not limited to four, and each of the first terminal unit 160 and the second terminal unit 162 may have terminals in a number corresponding to the number of PV modules constituting the solar cell unit 120.

[0032] The first terminal block 102 further includes temperature detection units 150A to 150D. The temperature detection units 150A to 150D are connected in series with each other. Both ends of the temperature detection units 150A to 150D connected in series are connected to a connector 154 by a pair of lead wires 152, and the temperature detection units 150A to 150D can be connected to an external circuit via the connector 154. Each of the temperature detection units 150A to 150D is, for example, a thermal fuse that melts down if an abnormal temperature occurs. The temperature detection units 150A to 150D are not limited to thermal fuses. They may be any device that can detect temperature, such as a temperature sensor. For example, even in the case of a temperature sensor that uses a change in resistance value due to temperature, if the resistance value of any of the temperature sensors connected in series changes significantly, this can be detected.

[0033] 2 shows a case where the temperature detecting units 150A to 150D are arranged inside the base member 140, but this is not limiting. The temperature detecting units 150A to 150D may be arranged in positions where heat generated in the terminals, i.e., heat generated due to insufficient tightening of the screws 146, can be efficiently transmitted. Therefore, the temperature detecting units 150A to 150D may be arranged above the conductive member 142 with an insulating member sandwiched therebetween. The number of temperature detecting units is not limited to four as shown in FIG. 2, as long as it is one or more.

[0034] 3, the second terminal block 104 is configured similarly to the first terminal block 102. The second terminal block 104 includes temperature detection units 150E-150H. The temperature detection units 150E-150H are connected in series to one another. Both ends of the temperature detection units 150E-150H connected in series are connected to connectors by lead wires, and the series-connected temperature detection units 150E-150H can be connected to an external circuit by the connectors. A plurality of terminals included in the third terminal unit 164 are connected to the input unit of the power conversion device 130, and a plurality of terminals included in the fourth terminal unit 166 are connected to the other terminals of the relays 110A-110D via wiring.

[0035] (Shut-off operation) An example of the configuration and operation of the control unit 108 when the temperature detection units 150A to 150H are thermal fuses will be described. With reference to FIG. 4, the control unit 108 includes, for example, an AND circuit 170. The AND circuit 170 performs an AND operation on the levels of two input signals and outputs the result (i.e., control signal S) to each relay of the relay unit 106. As described above, the temperature detection units 150A to 150D connected in series and included in the first terminal block 102 have one end grounded via resistor R1 and the other end supplied with DC voltage V1. One of the two inputs of the AND circuit 170 is connected to a connection node between the resistor R1 and the temperature detection unit 150D. Similarly, the temperature detection units 150E to 150H connected in series and included in the second terminal block 104 have one end grounded via resistor R2 and the other end supplied with DC voltage V1. The other of the two inputs of the AND circuit 170 is connected to a connection node between the resistor R2 and the temperature detection unit 150H. The resistance values ​​of resistors R1 and R2 are set in consideration of the resistance values ​​of the temperature detection units 150A to 150H and the DC voltage V1 so that the levels of the two input signals to the AND circuit 170 are high when none of the temperature detection units 150A to 150H are blown.

[0036] If no abnormal temperature is detected in either the first terminal block 102 or the second terminal block 104, both of the two input levels of the AND circuit 170 are high. The level of the control signal S, which is the output signal of the AND circuit 170, is high, each relay of the relay unit 106 is turned on (short-circuited), and the PV modules 122A to 122D are connected to the power conversion device 130. As a result, the power generated by the PV modules 122A to 122D and output from each output unit is supplied to the power conversion device 130 via the first terminal block 102, the relay unit 106, and the second terminal block 104.

[0037] On the other hand, if an abnormal temperature is detected in either the first terminal block 102 or the second terminal block 104, causing one of the temperature detection units 150A-150H to fuse, at least one of the two input signals to the AND circuit 170 changes from high to low. Therefore, the level of the control signal S, which is the output signal of the AND circuit 170, becomes low. The relays constituting the relay unit 106 turn off, and the connection between the PV modules 122A-122D and the power conversion device 130 is cut off. This allows heat generation to be detected if the screws in at least one of the first terminal block 102 and the second terminal block 104 are not tight enough during installation, repair, or maintenance (e.g., part replacement) of a system including the solar cell unit 120 and the power conversion device 130. If an abnormal temperature occurs, the connection between the solar cell unit 120 and the power conversion device 130 can be quickly cut off. This prevents damage (e.g., deformation, deterioration, and damage to the first terminal block 102 and the second terminal block 104) and fires.

[0038] Although it is not necessary for both the first terminal block 102 and the second terminal block 104 to include a temperature detection unit, by including a temperature detection unit in both the first terminal block 102 and the second terminal block 104, heat generated by insufficient tightening of the screws in both terminal blocks can be detected. This prevents the terminal blocks from becoming too hot, deforming, deteriorating, or being damaged.

[0039] By using thermal fuses in the temperature detection units 150A to 150H, if the terminal block generates heat and reaches an abnormal temperature, it is possible to reliably cut off the connection between the solar cell unit 120 and the power conversion device 130. The cut-off state is maintained by the fused thermal fuse, ensuring safety.

[0040] Although the above describes a case where all relays included in the relay unit 106 are turned off when an abnormal temperature is detected, the present invention is not limited to this. As described above, the DC voltage output from one PV module is transmitted through two transmission lines (for convenience, the high-potential side is referred to as the positive line and the low-potential side is referred to as the negative line), and a relay is connected to each line. Therefore, when an abnormal temperature is detected, it is sufficient to turn off at least one of the relays connected to the positive line and the negative line.

[0041] From the viewpoint of preventing the PID phenomenon, it is preferable to turn off at least the relay connected to the negative line. The glass surface of the solar panel is grounded. When the solar panel generates power and is connected to the power conditioner, the anode side of the diode is at a high voltage (e.g., +175 V to the power conditioner) and the cathode side is at a low voltage (e.g., −175 V to the power conditioner). Therefore, even if the anode side (i.e., positive line) of the solar panel is disconnected from the power conditioner, if the cathode side (i.e., negative line) remains connected, leakage current will flow from the glass surface (0 V) to the cathode side (−175 V). In contrast, if the cathode side (i.e., negative line) is disconnected from the power conditioner, leakage current will not flow. Therefore, by turning off at least the relay connected to the negative line among the relays included in the relay unit 106, the PID phenomenon in the PV modules 122A to 122D can be effectively suppressed. Therefore, instead of providing a relay on each of the positive line and negative line that outputs a DC voltage from one PV module as described above, a relay may be provided only on the negative line.

[0042] The control operation of the control unit 108 of the relay device 100 is not limited to disconnecting the solar cell unit 120 and the power conversion device 130. The control unit 108 may connect or disconnect the solar cell unit 120 and the power conversion device 130 depending on the power generation state of the solar cell unit 120. That is, the control unit 108 executes a first step of causing the relays 110A to 110D of the relay unit 106 to connect the PV modules 122A to 122D and the power conversion device 130 depending on the output of the PV modules 122A to 122D of the solar cell unit 120. The control unit 108 executes a second step of detecting the occurrence of an abnormal temperature in at least one of the first terminal block 102 and the second terminal block 104. Furthermore, the control unit 108 executes a third step of causing the relays 110A to 110D to disconnect the PV modules 122A to 122D and the power conversion device 130 depending on the detection result of the second step. As a result, if the screws in the first terminal block 102 and the second terminal block 104 are not tight enough during installation, repair, or maintenance of a system including the solar cell unit 120 and the power conversion device 130, heat generation caused by this can be detected. If an abnormal temperature occurs, the connection between the solar cell unit 120 and the power conversion device 130 can be quickly cut off. Therefore, damage to the first terminal block 102 and the second terminal block 104 and the occurrence of fires, etc. can be prevented in advance.

[0043] Although the above description is directed to a case where the control unit 108 includes the AND circuit 170 (see FIG. 4 ), this is not limiting. Any circuit that outputs a shutoff signal to the relay unit 106 in response to an abnormal temperature being detected by a temperature detection unit included in at least one of the first terminal block 102 and the second terminal block 104 can be used in place of the control unit 108. For example, as shown in FIG. 5 , a control unit 180 using a NOR circuit 172 instead of the AND circuit 170 may be used in place of the control unit 108. The NOR circuit 172 performs a NOR operation on the levels of two input signals and outputs the result (i.e., control signal S) to each relay of the relay unit 106. The control unit 180 shown in FIG. 5 is the control unit 108 shown in FIG. 4 in which the AND circuit 170 is replaced by the NOR circuit 172. 5, the resistors R1 and R2 shown in FIG. 4 are eliminated, and the temperature detection units 150D and 150H are directly grounded. A resistor R3 is connected between the temperature detection unit 150A and the DC voltage V1, and a resistor R4 is connected between the temperature detection unit 150E and the DC voltage V1. One of the two inputs of the NOR circuit 172 is connected to the connection node between the resistor R3 and the temperature detection unit 150A, and the other is connected to the connection node between the resistor R4 and the temperature detection unit 150E. The resistance values ​​of the resistors R3 and R4 are set, taking into account the resistance values ​​of the temperature detection units 150A-150H and the DC voltage V1, so that when none of the temperature detection units 150A-150H is blown, the levels of the two input signals to the NOR circuit 172 are low.

[0044] The control unit 180 shown in FIG. 5 functions in the same manner as the control unit 108 shown in FIG. 4. That is, if no abnormal temperature is detected in either the first terminal block 102 or the second terminal block 104, both of the two input levels of the NOR circuit 172 are low. The level of the control signal S, which is the output signal of the NOR circuit 172, is high, the relays of the relay unit 106 are turned on (short-circuited), and the PV modules 122A to 122D and the power conversion device 130 are connected. On the other hand, if an abnormal temperature is detected in either the first terminal block 102 or the second terminal block 104, and one of the temperature detection units 150A to 150H is blown out as a result, at least one of the two input signals of the NOR circuit 172 changes from low to high. As a result, the level of the control signal S, which is the output signal of the NOR circuit 172, becomes low, the relays of the relay unit 106 are turned off, and the connection between the PV modules 122A to 122D and the power conversion device 130 is interrupted.

[0045] (Specific configuration example) A specific configuration example will be shown with reference to FIG. 6. In a solar power generation system, the output voltage of a solar cell module changes depending on the state of sunlight irradiating the solar cell module. Therefore, a relay is controlled accordingly. Here, taking into consideration this relay control, a function is realized to turn off the relay in the event of an abnormal temperature. In FIG. 6, elements with the same reference numerals as those in FIG. 1 have the same functions as those in FIG. 1. Therefore, the following description will not be repeated and will mainly focus on the differences from FIG. 1.

[0046] 1, one solid line represents two wires transmitting a DC voltage, but in FIG. 6, each of the two wires transmitting a DC voltage is represented by a single solid line. Each of the PV modules 122A to 122D constituting the solar cell unit 120 is connected to two relays constituting the relay unit 106 via the first terminal block 102. That is, the positive line of the PV module 122A is connected to the relay 110Ap via the first terminal block 102, and the negative line is connected to the relay 110An via the first terminal block 102. The relays 110Ap and 110An correspond to the relay 110A shown in FIG. 1. The same applies to the PV modules 122B to 122D. That is, the positive line of the PV module 122B is connected to the relay 110Bp via the first terminal block 102, and the negative line is connected to the relay 110Bn via the first terminal block 102. The positive line of the PV module 122C is connected to the relay 110Cp via the first terminal block 102, and the negative line is connected to the relay 110Cn via the first terminal block 102. The positive line of the PV module 122D is connected to the relay 110Dp via the first terminal block 102, and the negative line is connected to the relay 110Dn via the first terminal block 102. The relays 110Bp and 110Bn, the relays 110Cp and 110Cn, and the relays 110Dp and 110Dn correspond to the relays 110B, 110C, and 110D shown in FIG. 1, respectively. The temperature detection units 150A to 150H included in the first terminal block 102 and the second terminal block 104 are assumed to be thermal fuses.

[0047] The control unit 108 includes a first diode unit 200, a second diode unit 202, a voltage comparison unit 204, a timer 206, an arithmetic unit 208, a transistor 210, and a switch 212. The positive lines of the PV modules constituting the solar cell unit 120 are connected to the voltage comparison unit 204 via the first terminal block 102 and each diode included in the first diode unit 200. The negative lines of the PV modules constituting the solar cell unit 120 are connected to the voltage comparison unit 204 via the first terminal block 102 and each diode included in the second diode unit 202.

[0048] The voltage comparator 204 detects the difference between two input signals (i.e., voltages) and outputs a signal corresponding to the detected difference to the timer 206. If the detected difference is less than a predetermined threshold value Th, the voltage comparator 204 outputs a first-level signal (e.g., low level). If the detected difference is equal to or greater than the threshold value Th, the voltage comparator 204 outputs a second-level signal (e.g., high level). The threshold value Th is, for example, a DC voltage of 45 V. The threshold value Th may be generated internally in the voltage comparator 204 or supplied externally to the voltage comparator 204. Note that the voltage comparator 204 may have an internal constant corresponding to the threshold value rather than generating the threshold voltage itself. The cathodes of the four diodes in the first diode unit 200 are connected to each other, and the anodes of the four diodes in the second diode unit 202 are connected to each other. Therefore, if the output voltage of at least one of the four PV modules is equal to or greater than the threshold value Th, the voltage comparator 204 outputs a second-level signal. The voltage comparator 204 is implemented, for example, by a comparator. If a Schmitt trigger type comparator is used, the output signal can be stabilized even if the detected difference fluctuates within a predetermined range, which is preferable.

[0049] If the signal input from the voltage comparator 204 is at the first level, the timer 206 outputs a low-level signal to the calculator 208. If the signal input from the voltage comparator 204 becomes the second level, the timer 206 outputs a high-level signal to the calculator 208. Thereafter, if the signal input from the voltage comparator 204 returns to the first level, the timer 206 measures the time for which the first level is maintained. If the signal input from the voltage comparator 204 is maintained at the first level for a predetermined time, the timer 206 outputs a low-level signal to the calculator 208. The predetermined time is, for example, 30 minutes. If the first level is not maintained for the predetermined time, i.e., if the signal input from the voltage comparator 204 becomes the second level again before the predetermined time has elapsed, the timer 206 resets the measured time.

[0050] The switch 212 is, for example, a mechanical switch, and switches two terminals between a short-circuited state (hereinafter referred to as "on") and an open state (hereinafter referred to as "off") in response to a human operation. The switch 212, the temperature detection units 150A to 150D connected in series and included in the first terminal block 102, and the temperature detection units 150E to 150H connected in series and included in the second terminal block 104 are connected in series. A DC voltage of 5V is supplied to one terminal of the series-connected switch 212 and temperature detection units 150A to 150H, and the other terminal is connected to the calculation unit 208. Therefore, when the switch 212 is turned on, the input signal to the calculation unit 208 becomes high level.

[0051] The calculation unit 208 performs an AND operation on the two input signals and outputs a signal according to the result to the transistor 210. The transistor 210 is an NPN transistor. If the levels of the two input signals are both high, the calculation unit 208 outputs a high-level signal to the base of the transistor 210. This turns the transistor 210 on. If the level of at least one of the two input signals is low, the calculation unit 208 outputs a low-level signal to the base of the transistor 210. This turns the transistor 210 off.

[0052] When transistor 210 is turned on, relays 110Ap-110Dn constituting relay unit 106 are turned on. In Fig. 6, the connection between transistor 210 and relays 110Ap-110Dn constituting relay unit 106 is shown simply. Referring to Fig. 7, the drive circuits of relays 110Ap-110Dn (i.e., coils for controlling the on / off of the relays) are connected in parallel and connected between the emitter of transistor 210 and ground. Therefore, when transistor 210 is turned on, a DC voltage of approximately 12 V is applied to the drive circuit of each of relays 110Ap-110Dn, and each of relays 110Ap-110Dn is turned on.

[0053] The above-mentioned DC voltages of 5V and 12V are generated by a power supply unit 214. The power supply unit 214 includes a DC / DC converter, and converts the DC voltage supplied to the voltage comparison unit 204 via the first diode unit 200 and the second diode unit 202 into a predetermined DC voltage (including 5V and 12V) and outputs it. The switch 212 may be provided with surge protection components, a noise filter, and the like, as appropriate. The power supply unit 214 only needs to supply the power (i.e., voltage and current) necessary for the operation of each unit, and the voltage supplied by the power supply unit 214 is not limited to the above values.

[0054] When the switch 212 is turned on, one of the input signals to the calculation unit 208 becomes high level, as described above. When each of the PV modules 122A-122D generates power and the output voltage increases, and the difference between the voltages input to the voltage comparison unit 204 becomes equal to or greater than the threshold value Th (i.e., 45 V), as described above, a signal of the second level is output from the voltage comparison unit 204 to the timer 206, and a high-level signal is output from the timer 206 to the calculation unit 208. As a result, the levels of the two input signals to the calculation unit 208 both become high level, a high-level signal is output to the transistor 210, and the transistor 210 turns on. As a result, as described above, all of the relays 110Ap-110Dn constituting the relay unit 106 are turned on, the PV modules 122A-122D are connected to the power conversion device, and the output power of the PV modules 122A-122D is supplied to the power conversion device. Thereafter, when the output voltages of the PV modules 122A-122D decrease and the difference in voltages input to the voltage comparison unit 204 becomes less than the threshold value Th (i.e., 45 V), a signal of the first level is output from the voltage comparison unit 204 and the timer 206 measures time. If the time during which the output signal of the voltage comparison unit 204 is at the first level continues for a predetermined time or longer, the timer 206 outputs a low-level signal to the calculation unit 208. As a result, the calculation unit 208 outputs a low-level signal to the transistor 210, which turns off the relays 110Ap-110Dn of the relay unit 106 and disconnects the PV modules 122A-122D from the power conversion device.

[0055] Assume that the PV modules 122A-122D are connected to the power converter 130, and the output power of the PV modules 122A-122D is being supplied to the power converter 130. In this state, assume that heat is generated in the first terminal block 102 and the second terminal block 104 due to insufficient tightening of screws. When the temperature becomes abnormal, one of the temperature detectors 150A-150H included in the first terminal block 102 and the second terminal block 104 melts down. As a result, a voltage of 5V is no longer supplied to the input terminal connected to the temperature detector 150A-150H out of the two input terminals of the calculation unit 208, and the level of the output signal of the calculation unit 208 becomes low. Therefore, the transistor 210 turns off, and all of the relays 110Ap-110Dn turn off, thereby cutting off the connection between the PV modules 122A-122D and the power converter 130. 6, if the screws of at least one of the first terminal block 102 and the second terminal block 104 are not tight enough during installation, repair, or maintenance of a system including the solar cell unit 120 and the power conversion device 130, heat generation caused by this can be detected. If an abnormal temperature occurs, the connection between the solar cell unit 120 and the power conversion device 130 can be quickly cut off. Therefore, damage (for example, deformation, deterioration, and damage to the first terminal block 102 and the second terminal block 104) and the occurrence of fires, etc. can be prevented in advance.

[0056] By providing the switch 212, installation, repair, or maintenance work of a system including the solar cell unit 120 and the power conversion device 130 can be performed safely. That is, if the switch 212 is turned off during installation, repair, or maintenance of a system including the PV modules 122A-122D, it is possible to prevent the relays of the relay unit 106 from being turned on even if power is generated by the PV modules 122A-122D during the work. Therefore, it is possible to prevent the generated power from being supplied to the power conversion device 130, etc., and it is possible to perform the work safely.

[0057] Since the switch 212 is connected in series to the temperature detection units 150A to 150H of the first terminal block 102 and the second terminal block 104, simply turning off the switch 212 can reproduce the same state as when the thermal fuse is blown, making it easy to achieve a safe working environment.

[0058] The transistor 210 may be any device capable of controlling the power supply to the relay drive circuit, and may be a field effect transistor (FET) or the like. The location of the transistor 210 is not limited to the location shown in FIG. 7. The transistor 210 may be placed between the drive circuit of the parallel-connected relays 110Ap-110Dn and the ground. That is, a DC voltage of 12 V may be directly supplied to one end of the drive circuit of the parallel-connected relays 110Ap-110Dn, and the other end may be connected to the emitter of the transistor 210, with the collector of the transistor 210 being grounded.

[0059] 7, a PNP transistor may be used instead of the transistor 210. In this case, a DC voltage of 12V is supplied to the emitter of the PNP transistor, and the collector is grounded via the drive circuit of the parallel-connected relays 110Ap-110Dn. The calculation unit 208 may include a NAND circuit that inverts and outputs the result of an AND operation, and the output may be connected to the base of the PNP transistor. If both of the two input signals to the NAND circuit are high, a low-level signal is output to the base of the PNP transistor. This turns the PNP transistor on. If at least one of the two input signals is low, a high-level signal is output to the base of the PNP transistor. This turns the PNP transistor off. Alternatively, the PNP transistor may be disposed between the drive circuit of the parallel-connected relays 110Ap-110Dn and ground.

[0060] The position of the switch 212 is not limited to the position shown in FIG. 6 . The switch 212 may be connected in series to the temperature detection units 150A to 150H. For example, the switch 212 may be disposed between the temperature detection units 150A to 150D connected in series and the temperature detection units 150E to 150H connected in series. The switch 212 may also be disposed between the temperature detection units 150E to 150H connected in series and one input terminal of the calculation unit 208. The switch 212 may also be disposed between the timer 206 and the calculation unit 208, or between the voltage comparison unit 204 and the timer 206. In either case, when the switch 212 is off, one of the two input signals of the calculation unit 208 can be prevented from going high. Therefore, a high-level signal is not output from the calculation unit 208, and the relays of the relay unit 106 can be prevented from being turned on.

[0061] Furthermore, since the switch 212 is intended to prevent each relay of the relay unit 106 from turning on, it may be disposed between the transistor 210 and the DC voltage 12V, as shown in Fig. 8. The switch 212 may also be disposed between the emitter of the transistor 210 and the drive circuits of the relays 110Ap to 110Dn connected in parallel. This prevents current from flowing through the drive circuits of the relays of the relay unit 106 when the switch 212 is off, thereby preventing each relay from turning on. This allows safe installation work to be performed during installation, repair, or maintenance of a system including a PV module.

[0062] (Energy storage system) The relay device 100 can be provided in, for example, a power storage system. Referring to Fig. 9, the power storage system 300 includes the relay device 100 shown in Fig. 1 and a power storage device 302. The power storage device 302 includes a power conversion device 304 and a storage battery 306 that stores DC power supplied from the power conversion device 304. The power conversion device 304 corresponds to the power conversion device 130 shown in Fig. 1. A first input / output unit 308 of the power conversion device 304 is connected to the second terminal block 104. Specifically, as described above, the first input / output unit 308 is connected to a terminal included in the third terminal block 164 shown in Fig. 3. A second input / output unit 310 of the power conversion device 304 is connected to the storage battery 306. An external power supply, for example, is connected to the first terminal block 102.

[0063] 1, DC power generated by PV modules 122A to 122D is supplied to power conversion device 304 via relay device 100. Power conversion device 304 converts the supplied DC voltage into a DC voltage suitable for charging storage battery 306, outputs the DC voltage, and charges storage battery 306. Also, for example, when wiring for supplying commercial power (AC power) is connected to first terminal block 102 of relay device 100, power conversion device 304 converts the supplied AC voltage into a DC voltage suitable for charging storage battery 306, outputs the DC voltage, and charges storage battery 306.

[0064] By including the relay device 100 in the power storage system 300, if the screws in the terminal block are not tight enough during installation, repair, or maintenance of the power storage system 300, heat generation caused by this can be detected. If an abnormal temperature occurs, the connection between the power storage device 302 and the external power source can be quickly cut off. This prevents the terminal block from becoming too hot, which can cause deformation, deterioration, and damage.

[0065] (Variation) The relay device 100 may be included in a power storage device. Referring to Fig. 10, a power storage device 320 includes the relay device 100, the power conversion device 304, and the storage battery 306 shown in Fig. 9. For example, the relay device 100, the power conversion device 304, and the storage battery 306 are housed in a single housing. The power storage device 320 functions in the same manner as the power storage system 300 shown in Fig. 9.

[0066] This allows the connection between relay device 100 and power storage device 302, i.e., the connection between the terminal included in third terminal portion 164 (see FIG. 3) of second terminal block 104 and first input / output unit 308, to be reliably performed in a factory or the like that manufactures power storage device 320. Therefore, with regard to second terminal block 104, it is possible to prevent insufficient tightening of the screws in the terminal block, which is a cause of heat generation.

[0067] The second terminal block 104 included in the power storage device 320 may be a normal terminal block that does not include the temperature detection units 150E-150H. When installing the power storage device 320, there is a possibility that the screws may not be tightly fastened when connecting an external power source (e.g., a PV module) to the first terminal block 102. To address this issue, as described above, if an abnormal temperature is detected by the temperature detection units 150A-150D of the first terminal block 102, the control unit 108 can turn off the relays included in the relay unit 106, thereby disconnecting the external power source from the power conversion device 304. That is, if the screws in the first terminal block 102 are not tightly fastened during installation, repair, or maintenance of the power storage device 320, heat generation caused by the insufficient fastening can be detected. If an abnormal temperature occurs, the connection between the external power source and the power storage device can be quickly disconnected. This prevents the first terminal block 102 from becoming too hot, deforming, deteriorating, or being damaged.

[0068] (Solar power generation system) The relay device 100 can be provided in, for example, a solar power generation system. Referring to Fig. 11, a solar power generation system 400 includes a solar cell unit 402, the relay device 100 shown in Fig. 1, and a power storage device 302. The solar cell unit 402 has the same configuration as the solar cell unit 120 shown in Fig. 1 and functions in the same way. The power storage device 302 has the same configuration as the solar cell unit 120 shown in Fig. 9 and functions in the same way.

[0069] During installation, repair, or maintenance (e.g., part replacement) of the photovoltaic power generation system 400, there is a possibility that the screws in the first terminal block 102 and the second terminal block 104 may not be tightened properly. If the screws are not tightened properly and an abnormal temperature occurs in the first terminal block 102 and the second terminal block 104 during operation of the photovoltaic power generation system 400 (i.e., during power generation by the solar cell unit 402), the relay device 100 can quickly cut off the connection between the solar cell unit 402 and the power conversion device 304. This makes it possible to prevent damage to the terminal blocks and the occurrence of fires, etc.

[0070] In the above description, the relay device 100 is described as having the first terminal block 102 and the second terminal block 104 on both sides of the relay unit 106. However, this is not limiting. A terminal block including a temperature detection unit may be provided on only one side of the relay unit 106. For example, as described above as a modified example, if the possibility of insufficient tightening of the screws in the second terminal block 104 is low, the relay device 100 may include the first terminal block 102 but not the second terminal block 104. This allows heat generation due to insufficient tightening of the screws in the first terminal block 102 to be detected during installation, repair, or maintenance of a system including a solar cell module and a power conversion device. If an abnormal temperature occurs, the connection between the solar cell module and the power conversion device can be quickly cut off. This prevents damage to the first terminal block and the occurrence of fires, etc.

[0071] Although the present disclosure has been described above by explaining the embodiments, the above-described embodiments are merely examples, and the present disclosure is not limited to only the above-described embodiments. The scope of the present disclosure is defined by the claims in the claims, taking into consideration the description of the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wordings described therein. [Explanation of symbols]

[0072] 100 Relay Device 102 1st terminal block 104 2nd terminal block 106 Relay Section 108, 180 Control unit 110A, 110Ap, 110An, 110B, 110Bp, 110Bn, 110C, 110Cp, 110Cn, 110D, 110Dp, 110Dn Relays 120, 402 Solar Cell Department 122A, 122B, 122C, 122D PV modules 130, 304 Power conversion device 140 Base material 142 Conductive materials 144 Washer 146 screws 148 Bulkhead 150A, 150B, 150C, 150D, 150E, 150F, 150G, 150H Temperature detection unit 152 lead wire 154 Connector 160 1st terminal section 162 2nd terminal section 164 3rd terminal section 166 4th terminal section 170 AND Circuit 172 NOR circuit 200 First Diode Section 202 Second diode section 204 Voltage comparison section 206 Timer 208 Arithmetic section 210 Transistor 212 Switch 214 Power supply section 300 Energy Storage System 302, 320 Electricity storage device 306 Storage Battery 308 1st input / output section 310 2nd input / output section 400 Solar Power Generation System R1, R2, R3, R4 resistance V1 DC voltage S control signal

Claims

1. A relay device disposed between a solar power generation panel and a power conversion device, a first terminal block to which the solar panel is connected; a second terminal block to which the power conversion device is connected; a relay connected to the first terminal block and the second terminal block, and connecting or disconnecting the solar panel and the power conversion device according to an output of the solar panel; a temperature detection unit provided on at least one of the first terminal block and the second terminal block; a control unit that outputs a signal to the relay to interrupt the connection between the solar power generation panel and the power conversion device in accordance with a temperature detection result by the temperature detection unit; a switch that can be arbitrarily switched between an on state and an off state and that prevents the relay from turning on depending on the switched state, regardless of the output of the solar power generation panel and the temperature detection result.

2. The relay device according to claim 1 , wherein the temperature detector is provided in both the first terminal block and the second terminal block.

3. a first terminal block to which the solar panel is connected; a relay electrically connected to a power conversion device that converts power from the solar panel and the first terminal block, and that connects or disconnects the solar panel and the power conversion device according to an output of the solar panel; a temperature detection unit provided on the first terminal block; a control unit that outputs a signal to the relay to interrupt the connection between the solar power generation panel and the power conversion device in accordance with a temperature detection result by the temperature detection unit; a switch that can be arbitrarily switched between an on state and an off state and that prevents the relay from turning on depending on the switched state, regardless of the output of the solar power generation panel and the temperature detection result.

4. the temperature detection unit includes a thermal fuse, The relay device according to claim 1 , wherein the control unit outputs the signal in response to the fact that the thermal fuse has been blown.

5. A relay device described in any one of claims 1 to 4, wherein the switch is connected in series with the temperature detection unit.

6. The relay device according to claim 1 , wherein the temperature detection unit includes a thermal fuse.

7. The relay device according to claim 1 , wherein a negative output terminal of the solar panel is connected to the relay via the first terminal block.

8. The relay includes N relays, where N is an integer of 2 or more; the first terminal block has the N or more first terminals to which output portions of the solar power generation panel are connected, and the N or more second terminals to which the first terminals are connected, Each of the N relays is connected to a corresponding second terminal; The relay device according to claim 1 , wherein the control unit outputs the signal to the N relays in accordance with an output of the temperature detection unit.

9. The relay device according to claim 1 , wherein the relay device is provided in a power storage device including the power conversion device and a storage battery.

10. The relay device according to any one of claims 1 to 9; The power conversion device; a storage battery connected to an output section of the power conversion device.

11. The relay device according to any one of claims 1 to 9; The solar power generation panel; The power conversion device; a storage battery connected to the power conversion device.

12. a first terminal block to which the solar panel is connected; a second terminal block to which a power conversion device that converts power from the solar panel is connected; a relay connected to the first terminal block and the second terminal block, and connecting or disconnecting the solar panel and the power conversion device according to an output of the solar panel; a temperature detection unit provided on at least one of the first terminal block and the second terminal block; A control method for a relay device including a switch that can be arbitrarily switched between an on state and an off state and that prevents the relay from being turned on depending on the switched state, regardless of the output of the solar power generation panel and the temperature detection result by the temperature detection unit, In response to the switch being switched, preventing the relay from being turned on in accordance with the switched state; a first step of detecting, after the state that prevents the relay from being turned on is released by the switch, the occurrence of a temperature rise in at least one of the first terminal block and the second terminal block, in which the temperature detection unit reaches or exceeds a predetermined temperature; a second step of causing the relay to disconnect the solar power generation panel from the power conversion device in accordance with the detection result of the first step.

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