Battery Storage System

Abstract

To provide a storage battery system that does not require troublesome calculation such as creation of an equivalent model, and has a diagnostic function that does not require an external power source.SOLUTION: A storage battery system comprises a storage battery unit 1 configured by connecting a plurality of storage battery cells in series, and a diagnostic circuit 2 that diagnoses the storage battery unit 1. The diagnostic circuit 2 has: a short-circuit path 6 that divides the storage battery unit 1 into two storage battery blocks 11, and short-circuits each storage battery block 11 via a resistor 21; a controller CPU 77 that controls the on / off of the short-circuit path 6; a current sensor 21a that measures a current generated by the short-circuit ON operation; and a voltage sensor 3 that measures the voltage of the storage battery block 11. The controller CPU 77 calculates the internal resistance of the storage battery block 11 from the measured current and voltage, and diagnoses the degree of deterioration of the storage battery unit 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a storage battery system having a function for diagnosing the deterioration level of the storage battery units included therein. [Background technology]

[0002] As batteries deteriorate, they will no longer be able to function properly, so they need to be diagnosed periodically. This diagnosis is done by measuring the internal resistance. For example, in Patent Document 1, an alternating current generated by an external power source is applied to a storage battery, and the internal resistance value is calculated from the voltage value generated in the storage battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-134467 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned conventional technique for calculating internal resistance requires an external power source to inject AC current, and in order to create an equivalent model of the secondary battery, it is necessary to create a characteristic diagram that observes the internal impedance at each frequency.

[0005] In view of the above problems, the present invention has an object to provide a storage battery system with a diagnostic function that does not require complicated calculations such as creating an equivalent model, and does not require an external power source. [Means for solving the problem]

[0006] In order to solve the above problem, the invention of claim 1 is a storage battery system having a storage battery unit formed by connecting a plurality of storage battery cells in series, and is equipped with a diagnostic circuit for diagnosing the storage battery unit, the diagnostic circuit comprising: a short-circuit path that divides the storage battery unit into at least two storage battery blocks and shorts each storage battery block via a current limiting means; a short-circuit control unit that controls the on / off of the short-circuit path; a current measurement unit that measures the current flowing in the short-circuit path by the short-circuit on operation; a voltage measurement unit that measures the voltage of some of the storage battery cells in the storage battery block or the voltage of the entire storage battery block; a deterioration diagnosis unit that calculates the internal resistance of the storage battery block from the measured current and voltage and diagnoses the degree of deterioration of the storage battery unit; and a notification unit that notifies the diagnosis result. According to this configuration, the degree of deterioration is determined by short-circuiting the storage battery block and calculating the internal resistance, so that the determination can be made with simple control without requiring cumbersome calculations such as creating an equivalent model.

[0007] The invention of claim 2 is characterized in that in the configuration of claim 1, the diagnostic circuit uses the storage battery unit as an operating power source. With this configuration, no external power supply is required.

[0008] The invention of claim 3 is characterized in that, in the configuration described in claim 1 or 2, the storage battery unit consists of two storage battery blocks, one on the positive side and one on the negative side, and both storage battery blocks are provided with short-circuit paths, the two short-circuit paths have a common intermediate electric circuit, and a reactor for storing energy generated by the short-circuit current is arranged in the intermediate electric circuit, and the short-circuit control unit alternately performs short-circuit control between the two storage battery blocks, and in that case, performs control so that both short-circuit paths are turned off simultaneously for a certain period of time, and the energy stored in the reactor by the short-circuit current of one of the short-circuit paths is used as a charging current for the other storage battery block during switching operation. According to this configuration, the short-circuit current is used to charge the other blocks, so that only a small amount of power is required for the deterioration diagnosis. Effect of the Invention

[0009] According to the present invention, the degree of deterioration is determined by short-circuiting the storage battery block and calculating the internal resistance, so that the determination can be made with simple control without requiring troublesome calculations such as creating an equivalent model. [Brief description of the drawings]

[0010] [Figure 1] 1 is a configuration diagram showing an example of a storage battery system according to the present invention. [Diagram 2] FIG. 2 is a block diagram of a controller. [Diagram 3] 2A and 2B show the flow of short-circuit control of the battery system in FIG. 1, where FIG. 2A is an explanatory diagram showing short-circuiting an upper block, and FIG. 2B is an explanatory diagram showing the current flow after the short-circuit has been completed. [Figure 4] 2A and 2B show the flow of short-circuit control of the battery system in FIG. 1, where FIG. 2A is an explanatory diagram showing short-circuiting a lower block, and FIG. 2B is an explanatory diagram showing the current flow after the short-circuit has been terminated. [Diagram 5] FIG. 11 is a configuration diagram showing another example of the storage battery system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a configuration diagram showing an example of a storage battery system according to the present invention, in which 1 is a storage battery unit, 2 is a diagnostic circuit for diagnosing the state of the storage battery, 3 is a voltage sensor for measuring the voltage of the storage battery, and 4 is a power conversion device for converting the output power of the storage battery unit 1 into AC or DC of a predetermined voltage to supply it to a load (not shown).

[0012] The storage battery unit 1 is formed by connecting a plurality of storage battery cells in series, and a positive electrode terminal portion P1 and a negative electrode terminal portion P2 of the storage battery unit 1 are connected to a power conversion device 4 via power lines L11, L12. However, the series-connected storage battery cells are divided into two storage battery blocks 11 (a first storage battery block 11a and a second storage battery block 11b).

[0013] The two storage battery blocks 11 are configured to have substantially the same number of storage battery cells, and each includes a short-circuit path 6 (a first short-circuit path 6a and a second short-circuit path 6b). An intermediate electric circuit 9, which is a common electric circuit of the short-circuiting circuit 6, is connected to an intermediate point Q of the storage battery unit 1, which is a connection portion between the storage battery blocks 11. The voltage sensors 3 are installed to measure the voltage of each storage battery block 11 , and the measurement data is transmitted to the diagnostic circuit 2 .

[0014] The diagnostic circuit 2 is composed of a short circuit 6 and a controller 7 that controls a short circuit caused by the short circuit 6 and diagnoses deterioration. The short-circuit path 6 is provided with a resistor 21 as a current limiting means for limiting the short-circuit current, and a semiconductor element 22 for turning the short-circuit path 6 on / off, on both the first short-circuit path 6a and the second short-circuit path 6b, and the resistor 21 is provided with a current sensor 21a for measuring the short-circuit current.

[0015] Fig. 2 shows a block diagram of the controller 7. In Fig. 2, 71 denotes a first input IF to which voltage measurement data output by the two voltage sensors 3 is input, 72 denotes a second input IF to which current measurement data output by the two current sensors 21a provided in the resistor 21 is input, 73 denotes a control output unit that controls the on / off of the two semiconductor elements 22, 74 denotes a memory unit that stores threshold information for diagnosing deterioration of the storage battery unit 1, 75 denotes a display unit that displays the diagnosis result, 76 denotes a communication unit that transmits the diagnosis result to the outside, 77 denotes a controller CPU that controls the controller 7, and 78 denotes a power supply unit for the controller 7. The communication unit 76 has a communication line connection unit and transmits the diagnosis result to the outside via a wire. The controller CPU 77 functions as a short circuit control unit that controls the semiconductor device 22, and also functions as a deterioration diagnosis unit that diagnoses the deterioration of the storage battery unit 1.

[0016] The electric path connected to the positive electrode terminal P1 of the first short-circuit path 6a is also connected to the power supply unit 78 of the controller 7 via an electric path L21. The electric path connected to the negative electrode terminal P2 of the second short-circuit path 6b is also connected to the power supply unit 78 of the controller 7 via an electric path L22, and the storage battery unit 1 itself serves as the operating power source for the controller 7. The power supplied to the controller 7 is small and can be ignored, and the current value measured by the current sensor 21 a can be regarded as the short-circuit current of the storage battery block 11 .

[0017] The diagnosis of the storage battery unit 1 by the diagnosis circuit 2 configured as above is carried out as follows. Figures 3 and 4 are explanatory diagrams showing a state in which a current is passed through the short-circuit path 6, and the diagnosis will be described with reference to these Figures 3 and 4. The two semiconductor elements 22 are alternately turned on under the control of the controller CPU 77, so that short-circuit currents I1 and I3 alternately flow through the first short-circuit path 6a and the second short-circuit path 6b. Fig. 3(a) shows a state in which the semiconductor element 22 provided in the first short-circuit path 6a is turned on to short-circuit the first storage battery block 11a, and Fig. 4(a) shows a state in which the semiconductor element 22 provided in the second short-circuit path 6b is turned on to short-circuit the second storage battery block 11b.

[0018] The controller CPU 77 obtains information on the short-circuit currents I1, I3 flowing through the resistor 21 due to this short-circuit control from the current sensor 21a, and obtains voltage information of the storage battery block 11 from the voltage sensor 3, and calculates the internal resistance of the storage battery block 11 based on this information. Deterioration is diagnosed by comparing the calculated internal resistance value with a threshold value stored in the storage unit 74. The threshold value is set in multiple stages, and the stage in which the calculated internal resistance value is located is determined and the diagnosis result is output. If the diagnosis result indicates that the measured internal resistance is at a level that requires replacement of the storage battery cell, for example, warning information is output to notify that it is time to replace the cell. This output causes a warning to be displayed on the display unit 75, and information such as "It is time to replace the cell" is sent to the outside. Incidentally, the threshold does not have to be set in multiple stages, and only one threshold for determining replacement may be used.

[0019] In this way, the deterioration level of the storage battery unit 1 can be determined with simple control without requiring complicated calculations such as creating an equivalent model, by short-circuiting the storage battery block 11 to calculate the internal resistance and determine the deterioration level. Furthermore, since power for the diagnostic circuit 2 is supplied from the storage battery unit 1, no external power supply is required.

[0020] Here, the short-circuit switching control will be specifically described. The switching of the short-circuit operation between the first short-circuit path 6a and the second short-circuit path 6b is not performed continuously, but is performed after waiting for the reactor 8 that has stored the energy due to the short-circuit current to complete discharging (at a fixed time interval). Figures 3(b) and 4(b) are explanatory diagrams of the operation of the reactor 8 at this time, with Figure 3(b) showing the state immediately after the semiconductor element 22 of the first short-circuit path 6a is turned off, and Figure 4(b) showing the state immediately after the semiconductor element 22 of the second short-circuit path 6b is turned off. As shown in Figures 3(b) and 4(b), when the semiconductor element 22 is turned off, the power stored in the reactor 8 becomes the charging power for the other storage battery block 11 and is used for charging. I2 and I4 indicate this discharging current. When the charging operation is completed, the other semiconductor element 22 is turned on. For example, the ON time of one semiconductor element 22 is 1.0 second, and the switching time from when the other semiconductor element 22 is turned OFF until when the other semiconductor element 22 is turned ON is 0.5 second.

[0021] In this way, the charging current of one storage battery block 11 is used to charge the other storage battery block 11, so that only a small amount of power is required for the deterioration diagnosis.

[0022] 1, the first battery block 11a and the second battery block 11b of the storage battery unit 1 are configured with approximately the same number of storage battery cells, and the intermediate circuit 9 with a common short-circuit circuit 6 is connected to the midpoint Q, but they may be divided at a position biased toward the positive or negative electrode side of the storage battery unit 1. Diagnosis can be performed by setting a threshold value for determining the degree of deterioration depending on the number of storage battery cells that make up the storage battery block 11.

[0023] Fig. 5 is a configuration diagram showing another example of the battery system. Fig. 5 shows a case where the battery system is divided into three battery blocks 11, and a short-circuit path 6 is formed for each of the formed battery blocks 11. However, in this case, the short-circuit path 6 does not include a reactor, and the number of battery cells 12 constituting the battery blocks 11 differs for each block. Furthermore, the voltage sensor 3 does not need to measure the voltage of the entire storage battery block 11, and here measures the voltage of any one storage battery cell 12 for each block. Since the individual storage battery cells 12 do not deteriorate at different rates, it is possible to grasp the condition of the entire storage battery block 11 by simply measuring the voltage of one storage battery cell. As shown in FIG. 5, when the storage battery unit 1 is divided into three blocks, a short-circuit operation is performed for each storage battery block 11 in turn, and the internal resistance value is calculated.

[0024] In the above embodiment, the temperature of the storage battery unit 1 is not taken into consideration. However, it is also possible to obtain temperature information of the storage battery unit 1 or each storage battery block 11 and change the threshold value for determining the degree of deterioration based on the temperature information. Furthermore, the communication unit 76 transmits the diagnosis results to the outside via a communication line, but the information may be transmitted by PLC communication via a power line, or may be transmitted by IP communication. [Explanation of symbols]

[0025] DESCRIPTION OF SYMBOLS 1·· Battery unit, 2·· Diagnostic circuit, 3·· Voltage sensor (voltage measurement section), 6·· Short circuit, 7·· Controller, 8·· Reactor, 9·· Intermediate circuit, 11·· Battery block, 12·· Battery cell, 21·· Resistor (current limiting means), 21a·· Current sensor (current measurement section), 22·· Semiconductor element, 74·· Memory section, 75·· Display section (notification section), 76·· Communication section (notification section), 77·· Controller CPU (short circuit control section, deterioration diagnosis section), 78·· Power supply section.

Claims

1. A storage battery system including a storage battery unit configured by connecting a plurality of storage battery cells in series, a diagnostic circuit for diagnosing the storage battery unit; The diagnostic circuit divides the storage battery unit into at least two storage battery blocks, and a short circuit is provided to short each of the storage battery blocks via a current limiting means. A short circuit control unit that controls on / off of the short circuit path; a current measuring unit that measures a current flowing through the short circuit path when the short circuit is turned on; a voltage measurement unit that measures a voltage of a part of the storage battery cells of the storage battery block or a voltage of the entire storage battery block; a deterioration diagnosis unit that calculates an internal resistance of the storage battery block from the measured current and voltage and diagnoses a deterioration degree of the storage battery unit; A storage battery system comprising: a notification unit that notifies a diagnosis result.

2. 2. The storage battery system according to claim 1, wherein the diagnostic circuit uses the storage battery unit as an operating power source.

3. The storage battery unit is composed of two storage battery blocks, one on a positive side and one on a negative side, and both storage battery blocks are provided with the short-circuit path; The two short-circuit paths have a common intermediate electric path, and a reactor for storing energy generated by a short-circuit current is disposed in the intermediate electric path, The battery system according to claim 1 or 2, characterized in that the short-circuit control unit performs short-circuit control alternately between the two storage battery blocks, and at that time performs control in which both short-circuit paths are turned off simultaneously for a certain period of time, so that energy stored in the reactor by the short-circuit current of one of the short-circuit paths is used as a charging current for the other storage battery block during switching operation.

Images