Power supply system

Abstract

To provide a power supply system capable of more reliably detecting water immersion.SOLUTION: The present power supply system includes: a battery unit group in which a plurality of battery units are arranged while polarities in a vertical direction are aligned, each battery unit including a plurality of battery modules stacked electrically in series; a detecting section which detects parameters related to power supply of each of the plurality of battery modules; and a sensing section which senses water immersion in the battery unit group based on a comparison between predetermined parameters detected by the detecting section in any predetermined battery unit among the plurality of battery units and other parameters detected by the detecting section in any other battery units other than the predetermined battery unit among the plurality of battery units.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply system.

Background Art

[0002] A power supply system equipped with a battery is in use. When water ingress occurs in such a power supply system, abnormalities such as electric leakage may occur. Therefore, a power supply unit equipped with a sensor for detecting water ingress has been proposed (see, for example, Patent Documents 1-2). Further, for example, a power supply unit that determines water ingress based on the change per unit time of the voltage of a battery cell included in the power supply system has been proposed (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power supply units described in Patent Documents 1 and 2 above, since a sensor is added for detecting water ingress, it leads to an increase in the manufacturing cost of the power supply unit and makes it difficult to miniaturize the power supply unit. Further, in the power supply unit described in Patent Document 3 above, there is a risk of misdetecting a failure of the power supply unit as water ingress.

[0005] One aspect of the disclosed technology aims to provide a power supply system that can more reliably detect water ingress.

Means for Solving the Problems

[0006] One aspect of the disclosed technology is exemplified by the following power supply system: This power supply system comprises a group of battery units, each consisting of multiple battery modules electrically stacked in series and arranged with their polarities aligned vertically; a detection unit for detecting parameters related to the power supply of each of the multiple battery modules; and a detection unit for detecting water ingress into the group of battery units based on a comparison between predetermined parameters detected by the detection unit in one of the multiple battery units and other parameters detected by the detection unit in any other battery unit among the multiple battery units other than the predetermined battery unit.

[0007] With the above power supply system, water ingress is detected not based on parameters in any one of the multiple battery units, but based on a comparison between predetermined parameters detected in one of the predetermined battery units and other parameters detected in the other battery units. By comparing parameters from multiple battery units, it is suppressed that a failure in any of the battery units may be mistakenly detected as water ingress. In other words, the above power supply system can detect water ingress more reliably.

[0008] The above power supply system may have the following features: The detection unit includes a voltmeter for measuring the voltage of each of the plurality of battery modules, and the detection unit determines the voltage of the battery unit group based on the difference between the voltage value detected in any of the plurality of battery modules of the predetermined battery unit and the voltage value detected in any of the plurality of battery modules of the other battery unit. Water ingress is detected. When a short circuit occurs, the voltage of the battery modules located on the short circuit path drops. Therefore, water ingress into the battery unit group can be detected based on the difference between the voltage value detected in any of the multiple battery modules of the predetermined battery unit and the voltage value detected in any of the multiple battery modules of the other battery unit.

[0009] The above power supply system may have the following features. The detection unit includes a voltmeter for measuring the voltage of each of the plurality of battery modules. The detection unit calculates a first potential difference between the voltage value detected at the highest battery module among the plurality of battery modules of the predetermined battery unit and the voltage value detected at the lowest battery module among the plurality of battery modules of the predetermined battery unit. The detection unit also calculates a second potential difference between the voltage value detected at the highest battery module among the plurality of battery modules of the other battery unit and the voltage value detected at the lowest battery module among the plurality of battery modules of the other battery unit. Based on the first and second potential differences, the system detects water ingress of the battery unit group. A voltage difference occurs between a battery module that has been submerged in water and a battery module that has not been submerged. The above power supply system can detect water ingress of the battery unit group by using the voltage of the battery module that is less likely to be submerged because it is located at the highest position and the voltage of the battery module that is more likely to be submerged because it is located at the lowest position.

[0010] The above power supply system may have the following features. The detection unit includes a thermometer for measuring the temperature of each of the plurality of battery modules, calculates a first temperature difference between the temperature detected at the highest battery module among the plurality of battery modules of the predetermined battery unit and the temperature detected at the lowest battery module among the plurality of battery modules of the predetermined battery unit, calculates a second temperature difference between the temperature detected at the highest battery module among the plurality of battery modules of the other battery unit and the temperature detected at the lowest battery module among the plurality of battery modules of the other battery unit, and detects water ingress of the battery unit group based on the first temperature difference and the second temperature difference. The temperature of a battery module submerged in water will be affected by the water and will therefore be different from the temperature of a battery module that is not submerged. The above power supply system can detect water ingress of the battery unit group by using the temperature of the battery module that is less likely to be submerged because it is located at the highest position and the temperature of the battery module that is more likely to be submerged because it is located at the lowest position.

[0011] The above power supply system may have the following features. The detection unit includes a first ammeter positioned between the predetermined battery unit and the other battery unit, and a second ammeter positioned on the output side of the battery unit group. The detection unit detects water ingress into the battery unit group when the difference between the current value measured by the first ammeter and the current value measured by the second ammeter is greater than or equal to a predetermined threshold. If no short circuit path is formed due to water ingress, the current value measured by the first ammeter and the current value measured by the second ammeter will be approximately equal. Therefore, the power supply system can detect water ingress into the battery unit group when a difference of greater than or equal to a predetermined threshold occurs between the current value measured by the first ammeter and the current value measured by the second ammeter.

[0012] The above power supply system may have the following features: The detection unit includes a zero-phase current transformer positioned between the predetermined battery unit and the other battery unit, and the detection unit detects water ingress into the battery unit group when the current value indicating the short-circuit current detected by the zero-phase current transformer is greater than or equal to a predetermined threshold. If no short-circuit path is formed between the battery modules, the current value indicating the short-circuit current measured by the zero-phase current transformer will be approximately zero. Therefore, the power supply system can detect water ingress into the battery unit group when the current value indicating the short-circuit current is greater than or equal to a predetermined threshold. [Effects of the Invention]

[0013] This power supply system can more reliably detect flooding. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 shows an example of a power supply system according to an embodiment. [Figure 2] Figure 2 shows an example of the configuration of a battery module in an embodiment. [Figure 3] Figure 3 is a schematic diagram showing what happens when water ingress occurs in the power supply system according to this embodiment. [Figure 4] Figure 4 shows an example of the processing flow for flood detection by the power supply system. [Figure 5] Figure 5 shows a first modified example of the processing flow for flood detection by the power supply system. [Figure 6] Figure 6 shows a second modified example of the processing flow for flood detection by the power supply system. [Figure 7] Figure 7 shows a third modified example of the processing flow for flood detection by the power supply system. [Figure 8] Figure 8 shows an example of a power supply system according to the fourth modified example. [Figure 9] Figure 9 shows an example of the processing flow for water ingress detection by the power supply system according to the fourth modified example.

Best Mode for Carrying Out the Invention

[0015] <Embodiment> Hereinafter, embodiments will be further described with reference to the drawings. FIG. 1 is a diagram showing an example of a power supply system 1 according to an embodiment. The power supply system 1 includes a positive electrode line 2, an inter-unit connection line 3, a negative electrode line 4, a relay 5, a breaker 6, a fuse 7, a positive electrode output terminal 8, a negative electrode output terminal 9, a first battery unit 10a, a second battery unit 10b, and a control unit 100. When the first battery unit 10a and the second battery unit 10b are not distinguished, they are also referred to as the battery unit 10.

[0016] The power supply system 1 supplies power from the first battery unit 10a and the second battery unit 10b connected in series to a load via the positive electrode output terminal 8 and the negative electrode output terminal 9. The positive electrode 12a of the first battery unit 10a is connected to the positive electrode output terminal 8 by the positive electrode line 2. Also, the negative electrode 13b of the second battery unit 10b is connected to the negative electrode output terminal 9 by the negative electrode line 4. And the negative electrode 13a of the first battery unit 10a and the positive electrode 12b of the second battery unit 10b are connected by the inter-unit connection line 3. Each of the first battery unit 10a and the second battery unit 10b is an example of a "battery unit". The first battery unit 10a and the second battery unit 10b are an example of a "battery unit group".

[0017] An ammeter 21a for measuring the current flowing through the inter-unit connection line 3 is arranged on the inter-unit connection line 3. Also, an ammeter 21b for measuring the current flowing through the negative electrode line 4 is arranged between the negative electrode output terminal 9 of the negative electrode line 4 and the fuse 7. The current value measured by the ammeter 21a and the current value measured by the ammeter 21b are notified to the control unit 100 via signal lines not shown.

[0018] The first battery unit 10a is a unit in which battery modules 11a, 11b, 11c, and 11d are arranged in a row and connected in series. The second battery unit 10b is a unit in which battery modules 11e, 11f, 11g, and 11h are arranged in a row and connected in series. Each of the battery modules 11a, 11b, 11c, 11d, 11e, 11f, 11g, and 11h is, for example, a single secondary battery. Each of the battery modules 11a, 11b, 11c, 11d, 11e, 11f, 11g, and 11h is, for example, multiple secondary batteries. It may also be a battery module including a battery. When not distinguishing between storage battery modules 11a, 11b, 11c, 11d, 11e, 11f, 11g, and 11h, they are also referred to as storage battery module 11.

[0019] In the power supply system 1, the first battery unit 10a and the second battery unit 10b are arranged with their polarities aligned. That is, both the first battery unit 10a and the second battery unit 10b are arranged with the same polarity facing downwards (or upwards). In the example in Figure 1, both the first battery unit 10a and the second battery unit 10b are arranged with their negative terminals (negative terminal 13a, negative terminal 13b) facing downwards. Furthermore, the first battery unit 10a and the second battery unit 10b are arranged side by side at the same height, for example. Therefore, the inter-unit connection line 3 extends from below the first battery unit 10a to above the second battery unit 10b.

[0020] Furthermore, a circuit breaker 6 is positioned between the positive electrode 12a and the positive output terminal 8 on the positive electrode wire 2, and between the negative electrode 13b and the negative output terminal 9 on the negative electrode wire 4. The circuit breaker 6 is positioned higher than the battery unit 10. When the circuit breaker 6 is turned off, the current between the positive electrode 12a and the positive output terminal 8 on the positive electrode wire 2, and between the negative electrode 13b and the negative output terminal 9 on the negative electrode wire 4 is interrupted.

[0021] A relay 5 is placed between the positive output terminal 8 and the circuit breaker 6 on the positive electrode wire 2. The relay 5 can switch between a state where the current in the inter-unit connection wire 3 is interrupted and a state where the current is flowing. In addition, a fuse 7 is placed between the negative output terminal 9 and the circuit breaker 6 on the negative electrode wire 4. Note that the fuse 7 may be provided on the positive electrode wire 2 instead of the negative electrode wire 4, or on both the positive electrode wire 2 and the negative electrode wire 4. The fuse 7 blows when a current outside the allowable range flows through the negative electrode wire 4. When the fuse 7 blows, the current flowing through the negative electrode wire 4 is interrupted.

[0022] The control unit 100 can be considered as a computer having an arithmetic unit, memory device, etc. The control unit 100 operates by receiving power from the battery unit 10. The control unit 100 detects water ingress in the power supply system 1 by executing a predetermined program, etc. The control unit 100 is an example of a "detection unit".

[0023] Figure 2 shows an example of the configuration of a battery module 11 in an embodiment. The battery module 11 comprises a battery 111, a voltmeter 112, and a thermometer 113. The battery 111 is a secondary battery. The voltmeter 112 measures the voltage of the battery 111 (the potential difference between the positive and negative electrodes of the battery 111). The thermometer 113 measures the temperature of the battery 111. The voltage of the battery 111 measured by the battery 111 and the temperature of the battery 111 measured by the voltmeter 112 are communicated to the control unit 100 via signal lines (not shown). The voltmeter 112 and thermometer 113 are examples of "detection units".

[0024] Figure 3 schematically shows the case when flooding occurs in the power supply system 1 according to the embodiment. In Figure 3, the flooded area R1 schematically shows the area that has been flooded. In Figure 3, the battery module 11d, which is the lowest battery module of the first battery unit 10a, and the battery module 11h, which is the lowest battery module of the second battery unit 10b, are submerged in water due to flooding.

[0025] When battery modules 11d and 11h are submerged in water, a short circuit is formed, for example, as exemplified by the short circuit path W1. If current flows through such a short circuit path W1, the water in the submerged area R1 is electrolyzed by the current, generating hydrogen, which may cause a fire using the electrical equipment of the power supply system 1 as an ignition source.

[0026] When such a short-circuit path W1 is formed, the discharge current of battery modules 11e, 11f, and 11g increases compared to battery modules 11a, 11b, and 11c. As the discharge current increases, the voltage of battery modules 11e, 11f, and 11g decreases. In this embodiment, the presence or absence of water ingress is determined by detecting this voltage drop using the control unit 100.

[0027] Figure 4 shows an example of the processing flow for flood detection by the power supply system 1. Hereinafter, an example of the processing flow for flood detection by the power supply system 1 according to this embodiment will be described with reference to Figure 4.

[0028] In S1, the control unit 100 acquires the voltage values ​​measured by the voltmeter 112 from each of the battery modules 11a, 11b, 11c, 11e, 11f, and 11g. However, the battery module 11d located at the bottom of the first battery unit 10a and the battery module 11h located at the bottom of the second battery unit 10b may already be submerged due to flooding. If they are submerged, there is a risk that the voltage values ​​of battery modules 11d and 11h cannot be measured properly. Therefore, in S1, the control unit 100 acquires the voltage values ​​of the battery modules 11 excluding battery modules 11d and 11h. The voltage value measured by the voltmeter 112 of battery module 11a is an example of a "predetermined parameter". The voltage value measured by the voltmeter 112 of battery module 11e is an example of a "other parameter".

[0029] In S2, the control unit 100 calculates the difference in voltages obtained in S1. The control unit 100 calculates the difference between the voltage value of the battery module 11a located at the highest position in the first battery unit 10a and the voltage value of the battery module 11e located at the highest position in the second battery unit 10b. The control unit 100 calculates the difference between the voltage value of the battery module 11b located at the next highest position after battery module 11a in the first battery unit 10a and the voltage value of the battery module 11f located at the next highest position after battery module 11e in the second battery unit 10b. The control unit 100 calculates the difference between the voltage value of the battery module 11c located at the next highest position after battery module 11b in the first battery unit 10a and the voltage value of the battery module 11g located at the next highest position after battery module 11f in the second battery unit 10b. In other words, in S2, the difference in voltage values ​​of the battery modules 11, which are arranged at the same height in the first battery unit 10a and the second battery unit 10b, is calculated.

[0030] In S3, the control unit 100 determines whether any of the differences calculated in S2 are greater than or equal to a predetermined threshold. If any of the differences calculated in S2 are greater than or equal to a predetermined threshold (YES in S3), the process proceeds to S4. If at least one of the differences calculated in S2 is less than a predetermined threshold (NO in S3), the process proceeds to S5.

[0031] In S4, the control unit 100 determines that no flooding has occurred. In S5, the control unit 100 determines that flooding has occurred.

[0032] In this embodiment, the presence or absence of water ingress is detected based on the voltage values ​​obtained from each of the battery modules 11a, 11b, 11c, 11e, 11f, and 11g. The voltmeter 112 that measures the voltage of the battery module 11 is not a configuration added to the power supply system 1 for water ingress detection, but is a component normally provided in the power supply system. Therefore, according to this embodiment, the presence or absence of water ingress can be detected without adding sensors or the like for water ingress detection.

[0033] In this case, if water ingress is detected using the voltage value of a single battery module 11, there is a risk that a malfunction of that single battery module 11 may also be mistakenly detected as water ingress. Furthermore, in this embodiment, since the voltage difference between the battery modules 11 calculated in S2 is used for water ingress detection, the possibility of mistakenly detecting a malfunction of a battery module 11 as water ingress is suppressed. Therefore, according to this embodiment, water ingress can be detected more reliably. Note that in the power supply system 1 according to this embodiment, for example, the ammeter 21a may be omitted.

[0034] <First variation> In the embodiment described above, water ingress was detected based on the difference in voltage values ​​between battery modules 11 located at the same height in the first battery unit 10a and the second battery unit 10b. In the first modified example, water ingress is detected in each battery unit 10 based on the difference in voltage values ​​between the battery module 11 located at the highest position and the battery module 11 located at the lowest position. Components identical to those in the embodiment are denoted by the same reference numerals, and their descriptions are omitted. The first modified example will now be described with reference to the drawings.

[0035] Figure 5 shows a first modified example of the processing flow for flood detection by the power supply system 1. The first modified example of the processing flow for flood detection by the power supply system 1 will be described below with reference to Figure 5.

[0036] In S21, the control unit 100 calculates a voltage difference A, which is the difference between the voltage of battery module 11a and the voltage of battery module 11d. The control unit 100 also calculates a voltage difference B, which is the difference between the voltage of battery module 11e and the voltage of battery module 11h. Voltage difference A is an example of a "first potential difference". Voltage difference B is an example of a "second potential difference".

[0037] In S22, the control unit 100 determines whether the voltage difference A calculated in S21 is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S22), the process proceeds to S23. If it is less than the predetermined threshold (NO in S22), the process proceeds to S4.

[0038] In S23, the control unit 100 determines whether the voltage difference B calculated in S21 is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S23), the process proceeds to S5. If it is less than the predetermined threshold (NO in S23), the process proceeds to S24.

[0039] In S24, the control unit 100 determines that an abnormality has occurred in the battery unit 11. The process then proceeds to S4.

[0040] When a short-circuit path, such as the one illustrated by the short-circuit path W1 in Figure 3, is formed, the discharge current of battery modules 11d and 11h increases compared to the discharge current of other battery units 11, causing the voltage of battery modules 11d and 11h to drop. Therefore, in the first modified example, water ingress can be detected by detecting the potential difference between battery modules 11a and 11e, which are located in the least submerged position in the battery unit 11, and battery modules 11d and 11h, which are located in the most submerged position. In other words, even in the first modified example, the presence or absence of water ingress can be detected without adding sensors or the like for water ingress detection. Furthermore, in the first modified example, as in the embodiment, false detection of a battery module 11 failure as water ingress is suppressed.

[0041] <Second variation> In the embodiments and the first modified example described above, water ingress was detected using the voltage of the battery unit 11. In the second modified example, a method for detecting water ingress using the temperature of the battery unit 11 will be described. Hereafter, the same reference numerals will be used for components identical to those in the embodiments and the first modified example. Therefore, I will omit that explanation. Below, I will describe the second modified example with reference to the drawings.

[0042] Figure 6 shows a second modified example of the processing flow for flood detection by the power supply system 1. The second modified example of the processing flow for flood detection by the power supply system 1 will be described below with reference to Figure 6.

[0043] In S31, the control unit 100 obtains the temperature of the battery unit 11 measured by the thermometer 113 from each of the battery modules 11a, 11b, 11d, 11e, 11f, and 11h.

[0044] In S32, the control unit 100 calculates the temperature difference A between the temperature of battery module 11a and the temperature of battery module 11d, the temperature difference B between the temperature of battery module 11a and the temperature of battery module 11b, the temperature difference C between the temperature of battery module 11e and the temperature of battery module 11h, and the temperature difference D between the temperature of battery module 11e and the temperature of battery module 11f. Temperature difference A is an example of the "first temperature difference". Temperature difference C is an example of the "second temperature difference".

[0045] In S33, the control unit 100 determines whether the absolute value of the difference between temperature difference A and temperature difference B is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S33), the process proceeds to S34. If it is less than the predetermined threshold (NO in S33), the process proceeds to S4.

[0046] In S34, the control unit 100 determines whether the absolute value of the difference between temperature difference C and temperature difference D is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S34), the process proceeds to S5. If it is less than the predetermined threshold (NO in S34), the process proceeds to S24.

[0047] It is assumed that a temperature difference exists between the temperature of the submerged battery unit 11 and the temperature of the unsubmerged battery unit 11. Therefore, the control unit 100 calculates the temperature difference A between the temperature of battery module 11a, which is located in the least submerged position in the first battery unit 10a, and the temperature difference B between the temperature of battery module 11a and the temperature of battery module 11b, which is located in the next least submerged position after battery module 11a, and calculates the absolute value of the difference between temperature difference A and temperature difference B. In addition, the control unit 100 calculates the temperature difference C between the temperature of battery module 11e, which is located in the least submerged position in the second battery unit 10b, and the temperature difference D between the temperature of battery module 11e and the temperature of battery module 11f, which is located in the next least submerged position after battery module 11e, and calculates the absolute value of the difference between temperature difference C and temperature difference D. The control unit 100 then determines whether or not water is present based on the absolute value of the difference between temperature difference A and temperature difference B, and the absolute value of the difference between temperature difference C and temperature difference D.

[0048] The thermometer 113 that measures the temperature of the battery module 11 is not a component added to the power system 1 for water ingress detection, but is a component that is normally provided in the power system. Therefore, according to the second modification, the presence or absence of water ingress can be detected without adding sensors or the like for water ingress detection.

[0049] Furthermore, in the second modified example, by using the absolute value of the difference between temperature difference A and temperature difference B in the first battery unit 10a and the absolute value of the difference between temperature difference C and temperature difference D in the second battery unit 10b, the false detection of failures in the first battery units 10a and 10b as water damage is suppressed.

[0050] <Third variation> In the embodiments and modifications described above, water ingress was detected using the voltmeter 112 and thermometer 113 of the battery unit 11. In the third modification, water ingress is detected using ammeters 21a and 21b provided in the power supply system 1. Components identical to those in the embodiments, the first modification, and the second modification are denoted by the same reference numerals, and their descriptions are omitted. The third modification will now be described with reference to the drawings. Ammeter 21a is an example of a "first ammeter". Ammeter 21b is an example of a "second ammeter".

[0051] Figure 7 shows a third modified example of the processing flow for flood detection by the power supply system 1. The third modified example of the processing flow for flood detection by the power supply system 1 will be described below with reference to Figure 7.

[0052] In S41, the control unit 100 acquires the current value measured by the ammeter 21a and the current value measured by the ammeter 21b.

[0053] In S42, the control unit 100 determines whether the difference between the current value measured by ammeter 21a and the current value measured by ammeter 21b is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S42), the process proceeds to S4. If it is less than the predetermined threshold (NO in S42), the process proceeds to S5.

[0054] If no short circuit occurs, the current value measured by ammeter 21a and the current value measured by ammeter 21b will be equal. On the other hand, if a short circuit path like the short circuit path W1 in Figure 3 is formed, a difference will occur between the current value measured by ammeter 21a and the current value measured by ammeter 21b. In other words, according to the third modified example, the presence or absence of water ingress can be determined by the difference between the current value measured by ammeter 21a and the current value measured by ammeter 21b.

[0055] <Fourth variation> In the fourth modification, the presence or absence of water ingress is detected using a zero-phase current transformer (ZCT) that detects short-circuit current instead of the ammeter 21a. Components identical to those in the embodiment, the first modification, the second modification, and the third modification are denoted by the same reference numerals, and their descriptions are omitted. The fourth modification will now be described with reference to the drawings.

[0056] Figure 8 shows an example of a power supply system 1a according to the fourth modification. Power supply system 1a differs from power supply system 1 in that it is equipped with a zero-phase current transformer 21c instead of an ammeter 21a. The zero-phase current transformer 21c can be described as an ammeter that measures the short-circuit current generated by a short circuit.

[0057] Figure 9 shows an example of the processing flow for flood detection by the power supply system 1a according to the fourth modified example. The following description of the example of the flood detection processing flow by the power supply system 1a will refer to Figure 9.

[0058] In S51, the control unit 100 obtains the current value of the short-circuit current from the zero-phase current transformer 21c. In S52, the control unit 100 determines whether the current value of the short-circuit current obtained in S51 is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold (YES in S52), the process proceeds to S4. If it is less than the predetermined threshold (NO in S52), the process proceeds to S5.

[0059] According to the fourth modification, even if the ammeter 21a in the third modification is replaced with a zero-phase current transformer 21c, This allows for the detection of flooding. However, in the early stages of flooding, depending on the sensor sensitivity of the ammeter 21a, the difference in current values ​​between ammeter 21a and ammeter 21b may become small, potentially reducing the accuracy of flood detection in the early stages. By using a zero-phase current transformer 21c instead of ammeter 21a, the accuracy of flood detection in the early stages can be improved.

[0060] The embodiments and modifications described above can be combined.

[0061] <Note 1> A battery unit group (10a, 10b) is formed by stacking multiple battery modules (11) electrically in series, with the polarity aligned in the vertical direction. The detection units (112, 113) detect parameters related to the power supply of each of the plurality of battery modules (11), The system includes a detection unit (100) that detects water ingress into the battery unit group (10a, 10b) based on a comparison between predetermined parameters detected by the detection unit (112, 113) in any predetermined battery unit (10) among the plurality of battery units (10) and other parameters detected by the detection unit (112, 113) in any other battery unit (10) among the plurality of battery units (10) other than the predetermined battery unit. Power supply system (1). [Explanation of symbols]

[0062] 1. Power supply system 1a. Power supply system 2. Positive electrode wire 3. Inter-unit connection cable 4. Negative electrode wire 5. Relay 6. Circuit breaker 7. Fuse 8. Positive output terminal 9. Negative output terminal 10. Battery Unit 10a ··First Battery Unit 10b · Second Battery Unit 11. Battery Unit 11a ··Battery module 11b ··Battery module 11c Battery Module 11d ··Battery module 11e Battery Module 11f ··Battery module 11g battery module 11h ··Battery module 12a·Positive electrode 12b...Positive electrode 13a·Negative electrode 13b··Negative electrode 21a·Ammeter 21b·Ammeter 21c...Zero phase current transformer 100 Control Unit 111 · Storage Battery 112··Voltmeter 113...Thermometer 300 unit inter-unit connection cable 400 Control Unit 500 Power System R1·Flood area W1 Short-circuit path

Claims

1. A group of battery units, each consisting of multiple battery modules electrically stacked in series, arranged with their polarity aligned in the vertical direction, A detection unit for detecting parameters related to the power supply of each of the aforementioned plurality of battery modules, The system includes a detection unit that detects water ingress into the battery unit group when the difference between a predetermined parameter detected by the detection unit in any predetermined battery unit among the plurality of battery units and another parameter detected by the detection unit in any other battery unit among the plurality of battery units other than the predetermined battery unit is greater than or equal to a predetermined threshold. Power supply system.

2. The detection unit includes a voltmeter for measuring the voltage of each of the plurality of battery modules. The detection unit detects water ingress into the battery unit group when the difference between the voltage value detected in any of the plurality of battery modules of the predetermined battery unit and the voltage value detected in any of the plurality of battery modules of the other battery unit is greater than or equal to the predetermined threshold. The power supply system according to claim 1.

3. The detection unit includes a voltmeter for measuring the voltage of each of the plurality of battery modules. The detection unit is A first potential difference is calculated between the voltage value detected at the battery module located at the highest position among the plurality of battery modules of the predetermined battery unit and the voltage value detected at the battery module located at the lowest position among the plurality of battery modules of the predetermined battery unit. A second potential difference is calculated between the voltage value detected at the highest battery module among the multiple battery modules of the other battery unit and the voltage value detected at the lowest battery module among the multiple battery modules of the other battery unit. When the first potential difference and the second potential difference are greater than or equal to the predetermined threshold, water ingress into the battery unit group is detected. The power supply system according to claim 1.

4. The detection unit includes a thermometer for measuring the temperature of each of the plurality of battery modules. A first temperature difference is calculated between the temperature detected in the battery module located at the highest position among the plurality of battery modules of the predetermined battery unit and the temperature detected in the battery module located at the lowest position among the plurality of battery modules of the predetermined battery unit. A second temperature difference is calculated between the temperature detected in the battery module located at the highest position among the plurality of battery modules of the other battery unit and the temperature detected in the battery module located at the lowest position among the plurality of battery modules of the other battery unit. When the difference between the first temperature and the second temperature is greater than or equal to the predetermined threshold, water ingress into the battery unit group is detected. The power supply system according to claim 1.

5. The detection unit includes a first ammeter positioned between the predetermined battery unit and the other battery unit, and a second ammeter positioned on the output side of the battery unit group. The detection unit detects water ingress into the battery unit group when the difference between the current value measured by the first ammeter and the current value measured by the second ammeter is greater than or equal to the predetermined threshold. The power supply system according to claim 1.

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