WO2019188889A1

WO2019188889A1 - Power storage system and charging control method

Info

Publication number: WO2019188889A1
Application number: PCT/JP2019/012333
Authority: WO
Inventors: 中村　秀人; 純夫可知; 渉手塚
Original assignee: 古河電気工業株式会社; 古河電池株式会社
Priority date: 2018-03-26
Filing date: 2019-03-25
Publication date: 2019-10-03
Also published as: CN111937269A; JPWO2019188889A1

Abstract

The present invention suppresses unevenness in a charging state between battery rows by means of uniform charging with a simple configuration in a power storage system having a multi-parallel battery module. This storage system (100) is characterized by being provided with: a multi-parallel battery module (2) in which battery rows (20) comprising at least one lead battery cell (200) are connected to each other in a plurality of parallel rows; switches (4_1 to 4_n) which are provided to correspond to the respective battery rows and are connected in series between the battery rows and AC/DC conversion devices (3) corresponding to each other; and a control device (1), wherein the control device turns on the switches and supplies electric power from the AC/DC conversion devices to the battery rows so as to fully charge the battery rows by means of the uniform charging, and determines whether the uniform charging has been completed for the respective battery rows and turns off the switches of the battery rows to which the uniform charging is determined to have been completed.

Description

Power storage system and charge control method

The present invention relates to a power storage system and a charge control method, for example, a power storage system that controls charging of a lead storage battery, and a charge control method that controls charging of a lead storage battery.

Lead batteries are deteriorated in capacity due to repeated charge and discharge over a long period of time. In a power storage system using a lead storage battery, in order to remove the sulfation that is a cause of the deterioration of the lead storage battery, equal charge is periodically performed to bring the lead storage battery into a fully charged state.

In recent years, in response to demands for a large capacity of lead storage batteries, a single lead storage battery cell (single battery) or a plurality of storage battery arrays (also referred to as “strings”) in which a plurality of lead storage battery cells are connected in series are connected in parallel. Power storage systems equipped with parallel storage battery modules are becoming widespread.

In a power storage system equipped with a conventional multi-parallel storage battery module, uniform charging is managed throughout the multi-parallel storage battery. Therefore, due to the characteristics (internal resistance), temperature, etc. of the lead storage battery cell of each storage battery array, the storage battery array that becomes overcharged or insufficiently charged occurs due to variations in the charging current flowing between the storage battery arrays during uniform charging. However, there is a problem that the deterioration of the multi-parallel storage battery module proceeds.

As a conventional technique for solving this problem, a charge / discharge control device (chopper) for controlling the amount of charge / discharge is connected between the AC / DC converter (PCS: Power Conversion System) and the storage battery array, and connected to each storage battery array. There is known a technique for preventing overcharging or insufficient charging during equal charging by adjusting the charge / discharge amount of the storage battery array to which the charged / discharge control device corresponds (see Patent Document 1).

Japanese Patent No. 6247039

However, in the prior art disclosed in Patent Document 1 described above, it is necessary to provide a charge / discharge control device for adjusting the charge / discharge amount of each storage battery array for each storage battery array, which increases the cost of the power storage system. There is.

The present invention has been made in view of the above-described problems, and an object of the present invention is a storage system including a multi-parallel storage battery module. It is to suppress.

A power storage system according to a representative embodiment of the present invention controls a multi-parallel storage battery module in which a plurality of storage battery arrays including at least one lead storage battery cell are connected in parallel, and power transfer of the multi-parallel storage battery module. An AC / DC converter, a switch provided corresponding to each storage battery column, connected in series between the corresponding storage battery column and the AC / DC converter, and monitoring the state of the storage battery column for each storage battery column And a control device that controls on / off of the switch, and the control device turns on the switch to supply power from the AC / DC converter to the storage battery train, thereby fully charging the storage battery train. Performing equalization charging to make a state, determining whether or not the equalization charging is completed for each storage battery column, and determining whether the equalization charging is completed Characterized in that it turns off the serial switch.

According to the power storage system having the multi-parallel storage battery module according to the present invention, it is possible to suppress the variation in the charging state between the storage battery columns due to the equal charge with a simpler configuration.

It is a figure which shows the structure of the electrical storage system which concerns on one embodiment of this invention. It is a flowchart which shows the flow of the charge control method at the time of equal charge in the electrical storage system which concerns on embodiment. It is a figure for demonstrating the charge control method at the time of equal charge in the electrical storage system which concerns on embodiment. It is a figure for demonstrating the charge control method at the time of equal charge in the electrical storage system which concerns on embodiment. It is a figure for demonstrating the charge control method at the time of equal charge in the electrical storage system which concerns on embodiment. It is a figure for demonstrating the charge control method at the time of equal charge in the electrical storage system which concerns on embodiment. It is a timing chart which shows the charging current and discharge current of the storage battery row | line (lead storage battery) at the time of equal charge. It is a figure which shows the relationship between the charging current of a storage battery row | line | column and a charge condition (SOC) in the constant voltage charge period when equal charge is performed by a constant voltage-constant current charge system or a constant power-constant current charge system. It is a figure which shows an example of the time change of the charging current which flows into each storage battery row | line | column when performing uniform charge by a constant current-constant voltage charging system.

1. First, an outline of a typical embodiment of the invention disclosed in the present application will be described. In the following description, as an example, reference numerals on the drawings corresponding to constituent elements of the invention are shown in parentheses.

[1] A power storage system (100) according to a representative embodiment of the present invention includes a plurality of parallel storage battery arrays (20, 20_1 to 20_n) including at least one lead storage battery cell (200) connected in parallel. A storage battery module (2), an AC / DC converter (3) for controlling power transfer of the multi-parallel battery module, and a corresponding battery battery column and AC / DC converter provided for each storage battery column A switch (4_1 to 4_n) connected in series therebetween, and a control device (1) for monitoring the state of the storage battery row for each storage battery row and controlling on / off of the switch, the control device Turns on the switch and supplies electric power from the AC / DC converter to the storage battery train, thereby performing equal charge for bringing the storage battery train into a fully charged state, and the storage battery Wherein determining whether the uniform charging is completed, characterized by turning off the switch of the storage battery string charge equalization is determined to have been completed for each.

[2] In the power storage system, the control device includes an integrated value of charge currents of the storage battery trains after completion of the previous equal charge and the storage battery trains after the previous equivalent charge is completed. When the ratio with the integrated value of the discharge current becomes a predetermined value, it may be determined that the equal charge of the storage battery row is completed.

[3] In the power storage system, the control device decreases a charging current of the storage battery train to a predetermined value (Ith) in a constant voltage charging period in which the storage battery train is charged with a constant voltage in the equal charge. In this case, it may be determined that the equal charge of the battery array is completed.

[4] In the above power storage system, the equal charge starts charging the storage battery train with a constant current, and after the voltage of the storage battery array reaches a predetermined voltage, the constant current charging the storage battery array with a constant voltage − It may be performed by a constant voltage charging method.

[5] In the power storage system, the equal charge starts charging of the storage battery train with constant power, and after the voltage of the storage battery array reaches a predetermined voltage, the constant power charging the storage battery array with a constant voltage − It may be performed by a constant voltage charging method.

[6] A charge control method according to a typical embodiment of the present invention includes a multi-parallel storage battery module in which a plurality of storage battery rows (20, 20_1 to 20_n) including at least one lead storage battery cell (200) are connected in parallel. (2), the AC / DC converter (3) for controlling the power transfer of the multi-parallel storage battery module, and the corresponding AC / DC converter provided for each of the storage battery columns. The multiple power storage system includes a switch (4_1 to 4_n) connected in series and a control device (1) for monitoring the state of the storage battery row for each storage battery row and controlling on / off of the switch. A charge control method for a parallel storage battery module, wherein the control device turns on the switch to supply electric power from the AC / DC converter to the storage battery array, whereby the storage battery A first step (S1) for starting equal charge for bringing the battery into a fully charged state, and a second step (S2) for determining whether or not the equal charge has been completed for each storage battery train. The control device includes a third step (S3) of turning off the switch of the storage battery array that has been determined that the equal charge has been completed.

[7] In the charge control method, in the second step, the control device completes the integrated value of the charge current of the storage battery train after the previous equivalent charge is completed and the previous equivalent charge. Then, when the ratio with the integrated value of the discharge current of the storage battery row after that becomes a predetermined value, a step of determining that the equal charge of the storage battery row is completed may be included.

[8] In the above charge control method, the second step is performed in a constant voltage charging period in which the control device charges the storage battery train with a constant voltage in the equal charge. When the value (Ith) is reached, it may include a step of determining that the equal charge of the battery array is completed.

[9] In the charge control method, the equal charge starts charging the storage battery train with a constant current, and charges the storage battery train with a constant voltage after the voltage of the storage battery array reaches a predetermined voltage. -It may be performed by a constant voltage charging method.

[10] In the above charge control method, the equal charge starts constant charging of the storage battery train with constant power, and charges the storage battery train with a constant voltage after the voltage of the storage battery array reaches a predetermined voltage. -It may be performed by a constant voltage charging method.

2. Specific Examples of Embodiments Hereinafter, specific examples of embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to components common to the respective embodiments, and repeated description is omitted. It should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

<< Embodiment 1 >>
FIG. 1 is a diagram showing a configuration of a power storage system according to an embodiment of the present invention.
The power storage system 100 shown in the figure is a power storage system including, for example, a cycle-use lead storage battery. For example, the power storage system 100 supplies power to the load 6 from the power supply unit 5 (commercial power supply) at normal times, and supplies power to the load 6 from a lead storage battery for power backup when a power failure occurs.

The power supply unit 5 is a functional unit that supplies power to the power storage system 100 and the load 6. The power supply unit 5 is, for example, a commercial power source. In addition to the commercial power source, the power supply unit 5 may include a power generation facility that generates electric power based on renewable energy such as photovoltaic power generation (PV: Photovoltaics).

The power storage system 100 includes a storage battery module 2, an AC / DC converter 3, switches 4_1 to 4_n (n is an integer of 2 or more), and a control device 1.

The storage battery module 2 includes a lead storage battery configured to be able to charge and discharge electric power. The storage battery module 2 is a multi-parallel storage battery module in which a plurality of storage battery arrays including at least one lead storage battery cell are connected in parallel.

Specifically, as shown in FIG. 1, the storage battery module 2 has a structure in which a plurality of storage battery rows 20_1 to 20_n in which m (m is an integer of 1 or more) lead storage battery cells 200 are connected in series are connected in parallel. have. Hereinafter, the storage battery module 2 is also referred to as “multi-parallel storage battery module 2”. Further, when the storage battery columns 20_1 to 20_n are not distinguished from each other, they may be simply expressed as “storage battery column 20”.

The storage battery module 2 also includes a voltage sensor 201 that measures the output voltage (storage voltage) of each of the storage battery columns 20_1 to 20_n, and a current sensor 202 that measures the charging current and the discharge current of each of the storage battery columns 20_1 to 20_n. Each column 20_1 to 20_n has.

An AC / DC converter (hereinafter also referred to as a “PCS (Power Conditioning System)”) 3 is controlled by a controller 1 described later, and converts power between the power supply unit 5, the storage battery module 2, and the load 6. , A power conversion unit that controls transmission and reception of power among the power supply unit 5, the storage battery module 2, and the load 6.

For example, the PCS 3 converts AC power (AC) from the power supply unit 5 into DC power (DC) and supplies it to the storage battery module 2. The PCS 3 includes, for example, a DC / DC converter, an AC / DC converter (AC / DC), a switch circuit, and the like.

The switches 4_1 to 4_n are devices that switch connection and disconnection between the PCS 3 and the multi-parallel storage battery module 2. As shown in FIG. 1, the switches 4_1 to 4_n are provided corresponding to the storage battery columns 20_1 to 20_n, and are connected in series between the corresponding storage battery columns 20_1 to 20_n and the PCS3. The switches 4_1 to 4_n are, for example, electromagnetic switches (relays).

The control device 1 is a device that performs overall control of the entire power storage system 100. The control device 1 monitors the state of each of the storage battery columns 20_1 to 20_n for each of the storage battery columns 20_1 to 20_n, and controls on / off of the switches 4_1 to 4_n.

As shown in FIG. 1, the control device 1 includes a monitoring unit 11, a storage battery management unit 12, and a switch control unit 13.
The monitoring unit 11 is a data processing device that sequentially acquires physical quantities measured by the voltage sensor 201 and the current sensor 202 of the multi-parallel storage battery module 2 and monitors the state of the multi-parallel storage battery module 2 based on the physical quantities. The monitoring unit 11 is, for example, a BMU (Battery Management Unit).

The storage battery management unit 12 is a device that performs overall control of each component of the power storage system 100. The storage battery management unit 12 is, for example, an EMS (Energy Management System).
Specifically, the storage battery management unit 12 performs charge / discharge control of the multi-parallel storage battery module 2 by driving the PCS 3. For example, the storage battery management unit 12 performs multi-parallel processing by various charging methods such as a constant current-constant voltage charging (CCCV) method and a constant power-constant voltage charging method based on the monitoring result of the multi-parallel storage battery module 2 by the monitoring unit 11. The equal charge of the storage battery module 2 is executed.

Here, the constant current-constant voltage charging (CCCV) method starts charging the storage battery trains 20_1 to 20_n with a constant current, and after the voltages of the storage battery trains 20_1 to 20_n reach a predetermined voltage, the storage battery train with the constant voltage. This is a charging method for charging 20_1 to 20_n.

In the constant power-constant voltage charging method, charging of the storage battery trains 20_1 to 20_n is started with constant power, and after the voltage of the storage battery trains 20_1 to 20_n reaches a predetermined voltage, the storage battery trains 20_1 to 20_n are connected with the constant voltage. This is a charging method for charging.

The switch control unit 13 is a functional unit that switches on / off the switches 4_1 to 4_n in accordance with an instruction from the monitoring unit 11 or the storage battery management unit 12. For example, when the switches 4_1 to 4_n are relays, the switch control unit 13 is a signal generation circuit that generates a drive signal for switching on / off of the relay in accordance with an instruction from the monitoring unit 11 or the storage battery management unit 12. is there.

The monitoring unit 11 and the storage battery management unit 12 include, for example, a processor such as a CPU (Central Processing Unit), a storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and I / F as hardware resources. In a data processing apparatus having a peripheral circuit such as a circuit, the processor executes the various operations according to a program stored in the storage device to control the peripheral circuit.

The control device 1 periodically performs equal charge to bring the storage battery rows 20_1 to 20_n of the multi-parallel storage battery module 2 into a fully charged state in order to prevent deterioration of the lead storage batteries constituting the multi-parallel storage battery module 2.

The control device 1 turns on the switches 4_1 to 4_n to supply electric power from the PCS 3 to the storage battery trains 20_1 to 20_n, thereby performing equal charge for bringing the storage battery trains 20_1 to 20_n into a fully charged state, and the storage battery train 20_1. It is determined whether or not the equal charge is completed for each of 20 to n, and the switches 4_1 to 4_n of the storage battery rows 20_1 to 20_n that are determined to have completed the equal charge are turned off.

Hereinafter, a charge control method during equal charge in the power storage system 100 will be described in detail with reference to the drawings.

FIG. 2 is a flowchart showing the flow of the charge control method during equal charge in the power storage system 100. 3A to 3D are diagrams for explaining a charge control method during equal charge in power storage system 100. FIG.

Here, as shown in FIGS. 3A to 3D, the multi-parallel storage battery module 2 in the power storage system 100 includes three storage battery rows 20_1 to 20_3 having four (m = 4) lead storage battery cells 200 connected in series. This will be described by taking as an example the case of having a structure in which these are connected in parallel.

Further, in FIGS. 3A to 3D, charging currents of the storage battery columns 20_1 to 20_3 during equal charging are I1, I2, and I3, respectively, and I2> I1> I3 due to variations in characteristics of the storage battery columns 20_1 to 20_3. Suppose there is. 3A to 3D, the voltage sensor 201 and the current sensor 202 are not shown.

First, as shown in FIG. 3A, the control device 1 turns on the switches 4_1 to 4_3 to supply electric power from the PCS 3 to the storage battery arrays 20_1 to 20_3, thereby starting equal charge of the storage battery arrays 20_1 to 20_3 (steps). S1).

For example, the monitoring unit 11 requests the storage battery management unit 12 to perform equal charge. In response to a request from the monitoring unit 11, the storage battery management unit 12 turns on the switches 4_1 to 4_3 via the switch control unit 13 (or confirms that the switches are turned on) and a predetermined charging method (for example, The PCS 3 is driven so as to perform uniform charging with a constant current-constant voltage charging method), and the supply of power to the storage battery arrays 20_1 to 20_3 is started.

Next, the control device 1 determines whether or not there are storage battery rows 20_1 to 20_3 that have been charged evenly (step S2). Specifically, based on the measurement results of the output voltages and currents of the storage battery columns 20_1 to 20_3 acquired from the voltage sensor 201 and the current sensor 202 of the storage battery columns 20_1 to 20_3, the monitoring unit 11 stores the storage battery columns 20_1 to 20_3. It is determined whether or not the equal charge is completed. A specific determination method will be described later.

In step S2, when there is no storage battery row 20_1 to 20_3 for which equal charge has been completed, the control device 1 continues to perform equal charge for each of the storage battery rows 20_1 to 20_3.

On the other hand, when there are storage battery trains 20_1 to 20_3 for which equal charge has been completed in step S2, control device 1 turns off switches 4_1 to 4_3 of storage battery trains 20_1 to 20_3 for which equal charge has been completed (step S3). .

For example, in the case of the above-described example, since the charging currents of the storage battery columns 20_1 to 20_3 during equal charging are in the relationship of I2> I1> I3, the storage battery column 20_2 having the largest charging current I2 is first fully charged. When the monitoring unit 11 determines that the equal charging of the storage battery row 20_2 has been completed, the monitoring unit 11 notifies the storage battery management unit 12 of that. Receiving the notification, the storage battery management unit 12 instructs the switch control unit 13 to perform release control (off) of the switch 4_2, and the switch control unit 13 performs release control of the switch 4_2 as illustrated in FIG. 3B. Then, the storage battery array 20_2 is disconnected from the PCS 3.

Next, the control device 1 determines whether or not the equal charging of all the storage battery rows 20_1 to 20_3 has been completed (step S4). When the equal charge of all the storage battery rows 20_1 to 20_3 has not been completed, the process returns to step S2, and the processes from step S2 to step S4 described above are executed again.

For example, after the equal charging of the storage battery train 20_2 is completed and the storage battery train 20_2 is disconnected from the PCS 3, the charging currents of the storage battery trains 20_2 and 20_3 during the equal charging have a relationship of I1> I3. Therefore, the storage battery row 20_1 is fully charged next to the storage battery row 20_2. When the monitoring unit 11 determines that the equal charge of the storage battery row 20_1 has been completed, the monitoring unit 11 notifies the storage battery management unit 12 of that. Receiving the notification, the storage battery management unit 12 instructs the switch control unit 13 to perform release control (off) of the switch 4_1. As illustrated in FIG. 3C, the switch control unit 13 performs release control of the switch 4_1. Then, the storage battery array 20_1 is disconnected from the PCS3. Immediately after this, since the equal charge of the storage battery row 20_3 is still continued, the process returns to step S2.

Thereafter, when the storage battery train 20_3 is fully charged, the monitoring unit 11 notifies the storage battery management unit 12 that the equal charge of the storage battery train 20_3 has been completed. Receiving the notification, the storage battery management unit 12 instructs the switch control unit 13 to perform release control (off) of the switch 4_3, and the switch control unit 13 performs release control of the switch 4_3 as illustrated in FIG. 3D. Then, the storage battery array 20_3 is disconnected from the PCS3. Thereby, the equal charge of all the storage battery rows 20_1 to 20_3 is completed.

In step S4, when it is determined that the equal charging of all the storage battery rows 20_1 to 20_3 is completed, the control device 1 ends the control for the equal charging of the multi-parallel storage battery module 2 (step S5).
With the above procedure, equal charge of power storage system 100 according to the present embodiment is performed.

Next, a method for determining completion of equal charge will be described.
Two examples of the method for determining completion of equal charge according to the present embodiment are shown below.

First, a first example of a method for determining completion of equal charging by the power storage system 100 will be described.
As a first example, the control device 1 determines the integrated value of the charging current of the storage battery train 20 after completion of the previous equal charge and the discharge current of the storage battery train 20 after the previous equivalent charge is completed. When the ratio with the integrated value becomes a predetermined value, it is determined that the equal charge of the storage battery array 20 has been completed.

FIG. 4 is a timing chart showing the charging current and the discharging current of the storage battery train 20 (lead storage battery) during equal charging. In FIG. 4, the vertical axis represents current, and the horizontal axis represents time. Reference numeral 302 represents the charging current of the storage battery string 20, and reference numeral 303 represents the discharge current of the storage battery string 20.

First, the monitoring unit 11 of the control device 1 starts integration of the charging current and the discharging current for each of the storage battery rows 20_1 to 20_n at the timing when the uniform charging is completed. For example, in FIG. 4, at time t31 when the equal charging is completed, the monitoring unit 11 starts integrating the charging currents of the storage battery columns 20_1 to 20_n and starts integrating the discharging currents of the storage battery columns 20_1 to 20_n. .

Next, the monitoring unit 11 calculates the ratio between the integrated value of the charging current and the integrated value of the discharge current for each of the storage battery columns 20_1 to 20_n. Specifically, the ratio of the integrated value of the charging current to the integrated value of the discharge current is calculated.

Next, the monitoring unit 11 determines whether or not the calculated ratio has reached the ratio reference value for each of the storage battery columns 20_1 to 20_n.

Here, the ratio reference value is a value serving as a reference for determining the end of the constant voltage charging period in the uniform charging. In general, overcharge is performed so that the equal charge is 100% or more (for example, 104%) with respect to the discharge capacity. Therefore, the ratio reference value is preferably set to a value exceeding 100%, for example, a value in the range of 101% to 104%.

The monitoring unit 11 continues the integration of the charging current and the discharging current for each of the storage battery arrays 20_1 to 20_n when there is no storage battery array 20 in which the above ratio has reached the ratio reference value. On the other hand, when there is a storage battery string 20 in which the calculated ratio has reached the ratio reference value, the monitoring unit 11 determines that the uniform charging has been completed for the storage battery string 20 in which the calculated ratio has reached the ratio reference value. The monitoring unit 11 repeatedly executes the above processing until a determination result indicating that the equal charge has been completed for all the storage battery columns 20_1 to 20_n is obtained.

By executing the data processing according to the above procedure, it is possible to determine whether or not the uniform charging is completed for each of the storage battery columns 20_1 to 20_n.

Next, a second example of a method for determining completion of equal charging by the power storage system 100 will be described.
As a second example, in the constant voltage charging period in which the storage battery train 20 is charged with a constant voltage in equal charge, the control device 1 reduces the storage current of the storage battery train 20 to a predetermined value when it reaches a predetermined value. It is determined that the equal charge is completed.

FIG. 5 shows the state of charge (SOC: State Of Charge) of the storage battery train 20 during the constant voltage charging period when uniform charging is performed by the constant voltage-constant current charging method or the constant power-constant current charging method. It is a figure which shows a relationship.

As shown in FIG. 5, when the storage battery is charged at a constant voltage, the charge current tends to be smaller as the battery is nearly fully charged. Therefore, it is possible to detect the completion of the equal charge by monitoring the charge current for each storage battery train 20 during the constant voltage charge period in the equal charge. For example, in the constant voltage charging period, the monitoring unit 11 determines that the uniform charging has been completed when the charging current of each of the storage battery columns 20_1 to 20_n decreases and reaches a predetermined threshold value Ith.

FIG. 6 is a diagram illustrating an example of a temporal change in the charging current flowing through each storage battery row when equal charging is performed by the constant current-constant voltage charging method.
As described above, the storage battery rows 20_1 to 20_3 may vary in charging current during constant current charging depending on the temperature and the characteristics (internal resistance) of the lead storage battery cell 200 itself. For example, consider the case where I2>I1> I3 as in the above example.

The monitoring unit 11 of the control device 1 monitors the charging currents of the storage battery columns 20_1 to 20_3. In the above example, since I2> I1> I3, the charging current I2 of the storage battery train 20_2 first reaches the threshold value Ith. When the monitoring unit 11 detects that the charging current I2 of the storage battery train 20_2 has reached the threshold value Ith, the monitoring unit 11 determines that the equal charging of the storage battery train 20_2 has been completed.

Next, since I1> I3, the charging current I1 of the storage battery train 20_1 next reaches the threshold value Ith. When the monitoring unit 11 detects that the charging current I1 of the storage battery row 20_1 has reached the threshold value Ith, the monitoring unit 11 determines that the equal charging of the storage battery row 20_1 has been completed.

Finally, the charging current I3 of the storage battery row 20_3 next reaches the threshold value Ith. When the monitoring unit 11 detects that the charging current I3 of the storage battery train 20_3 has reached the threshold value Ith, the monitoring unit 11 determines that the equal charge of the storage battery train 20_3 has been completed.

As described above, by monitoring the charging current in the constant voltage charging period at the time of equal charging for each storage battery row 20, it is possible to determine whether or not the equal charge is completed for each storage battery row 20.

In the case of the constant power-constant voltage charging method, it is possible to determine whether or not the uniform charging is completed for each storage battery array 20 by the same method.

As described above, power storage system 100 according to the present embodiment is provided corresponding to each of multiple parallel storage battery modules 2 in which storage battery arrays 20_1 to 20_n including at least one lead storage battery cell 200 are connected in parallel, and each storage battery array 20_1 to 20_n. Control for monitoring the states of the switches 4_1 to 4_n connected in series between the corresponding storage battery trains 20_1 to 20_n and the AC / DC converter (PCS) 3 and the storage battery trains 20_1 to 20_n for each of the storage battery trains 20_1 to 20_n. The apparatus 1 is provided. The control device 1 turns on the switches 4_1 to 4_n and supplies power from the PCS 3 to the storage battery trains 20_1 to 20_n to perform equal charging, and determines whether or not the uniform charging is completed for each of the storage battery trains 20_1 to 20_n. Then, the switches 4_1 to 4_n of the storage battery arrays 20_1 to 20_n determined to have completed the uniform charging are turned off.

According to this, since the power supply from the PCS 3 to the storage battery columns 20_1 to 20_n performed at the time of equal charge can be controlled for each of the storage battery columns 20_1 to 20_n, the lead storage battery cell 200 of each storage battery column 20_1 to 20_n itself can be controlled. Even when the charging current flowing through each of the storage battery rows 20_1 to 20_n varies during equal charge due to characteristics (internal resistance), temperature, etc., each of the storage battery rows 20_1 to 20_n can be fully charged. It becomes possible. As a result, it is possible to prevent the generation of the storage battery rows 20_1 to 20_n that are overcharged or insufficiently charged due to variations in the charging current at the time of equal charge, so that the deterioration of the multi-parallel storage battery module 2 can be suppressed. It becomes possible.

In addition, since the power storage system 100 has a configuration in which the power supply to the storage battery columns 20_1 to 20_n from the PCS 3 during the uniform charging is switched between the power storage systems 20_1 to 20_n by the switches 4_1 to 4_n. Thus, since it is not necessary to separately provide a complicated charge / discharge control device for adjusting the charge / discharge amount of each storage battery row for each storage battery row, an increase in the cost of the power storage system can be suppressed as compared with the prior art. .

Therefore, according to the power storage system 100 according to the present embodiment, it is possible to suppress the deterioration of the multi-parallel storage battery module by suppressing the variation in the charging state between the storage battery columns due to the equal charge with a simpler configuration. .

Further, in the power storage system 100, the control device 1 includes the integrated value of the charging currents of the storage battery trains 20_1 to 20_n after completion of the previous equal charge and the storage battery trains 20_1 to 20_1 after the previous equivalent charge is completed. When the ratio with the integrated value of the discharge current of 20_n becomes a predetermined value, it is determined that the equal charge of the storage battery rows 20_1 to 20_n has been completed.

According to this, it is possible to more accurately determine whether or not the equal charge is completed for each storage battery row 20 regardless of the charge method of the equal charge.

Further, in the power storage system 100, the control device 1 causes the charging current of the storage battery trains 20_1 to 20_n to decrease to a predetermined value during a constant voltage charging period in which the storage battery trains 20_1 to 20_n are charged with a constant voltage in equal charge. In addition, it is determined that the equal charging of the storage battery rows 20_1 to 20_n has been completed.

According to this, in a power storage system that employs a uniform charging method that performs constant voltage charging just before the end of uniform charging, such as a constant current-constant voltage charging method and a constant power-constant voltage charging method, it is easier and more accurate. It is possible to determine whether or not the uniform charging is completed for each storage battery row 20.

<< Extended embodiment >>
Although the invention made by the present inventors has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof. Yes.

For example, in the above embodiment, the constant current-constant voltage charging method and the constant power-constant voltage charging method are exemplified as the charging method having a constant voltage charging period of equal charge, but is not limited thereto.

For example, constant current charging is performed first, and constant current charging at a current value lower than the previous current value after the storage battery voltage reaches a predetermined threshold is repeated a plurality of times. A multi-stage charging method may be used in which the lead storage battery is recovered to a fully charged state by performing voltage charging.

For example, the control device 1 determines that the equal charging of the storage battery trains 20_1 to 20_n is completed when the charging current of the storage battery trains 20_1 to 20_n decreases to a predetermined value during the constant voltage charging period of the multistage charging method. Thus, as in the case of the constant current-constant voltage charging method and the constant power-constant voltage charging method, it is possible to determine whether or not the uniform charging is completed for each storage battery array 20 more easily and accurately.

DESCRIPTION OF SYMBOLS 1 ... Control apparatus, 2 ... Storage battery module (multi-parallel storage battery module), 3 ... AC / DC converter (PCS), 4_1-4_n ... Switch, 5 ... Electric power supply part, 6 ... Load, 11 ... Monitoring part, 12 ... Storage battery management , 13... Switch control unit, 20, 20_1 to 20_n... Storage battery row, 100... Power storage system, 200 .. lead storage battery cell, 201... Voltage sensor, 202 ... current sensor, Ith.

Claims

A multi-parallel storage battery module in which a plurality of storage battery arrays including at least one lead storage battery cell are connected in parallel;
An AC / DC converter for controlling power transfer of the multi-parallel storage battery module;
A switch that is provided corresponding to each storage battery row, and that is connected in series between the corresponding storage battery row and the AC / DC converter;
A controller for monitoring the state of the storage battery row for each storage battery row and controlling on / off of the switch,
The control device turns on the switch and supplies power from the AC / DC converter to the storage battery train, thereby performing equal charge for making the storage battery train fully charged, and for each storage battery train, It is determined whether or not the equal charge has been completed, and the switch of the storage battery array that has been determined that the equal charge has been completed is turned off.
The power storage system according to claim 1,
The control device includes: an integrated value of the charging current of the storage battery string after completion of the equivalent charging performed last time and an integrated value of the discharging current of the storage battery string after completion of the uniform charging performed last time. When the ratio reaches a predetermined value, it is determined that the equal charge of the storage battery array is completed.
The power storage system according to claim 1,
In the constant voltage charging period in which the storage battery train is charged with the constant voltage in the equal charge, the control device performs the equal charge of the storage battery train when the charge current of the storage battery train decreases to a predetermined value. A power storage system characterized by determining that it has been completed.
The power storage system according to claim 3,
The equal charge is performed by a constant current-constant voltage charging method in which charging of the storage battery train is started by a constant current, and the storage battery train is charged by a constant voltage after the voltage of the storage battery train reaches a predetermined voltage. A storage battery system characterized by
The power storage system according to claim 3,
The equal charge is performed by a constant power-constant voltage charging method in which charging of the storage battery train is started by constant power and the storage battery train is charged by constant voltage after the voltage of the storage battery row reaches a predetermined voltage. A storage battery system characterized by
A multi-parallel storage battery module in which a plurality of storage battery arrays including at least one lead storage battery cell are connected in parallel, an AC / DC converter for controlling power transmission / reception of the multi-parallel storage battery module, and each storage battery array are provided correspondingly, A switch connected in series between the corresponding storage battery array and the AC / DC converter, and a control device that monitors the state of the storage battery array for each storage battery array and controls on / off of the switch. A charge control method for the multi-parallel storage battery module in the storage system,
A first step in which the control device turns on the switch and supplies power from the AC / DC converter to the storage battery train to start equal charge for bringing the storage battery train into a fully charged state;
A second step in which the control device determines whether or not the equal charge has been completed for each storage battery row;
A charge control method comprising: a third step of turning off the switch of the storage battery array in which the control device determines that the equal charge has been completed.
The charge control method according to claim 6, wherein
In the second step, an integrated value of the charging current of the storage battery train after the controller performs the previous equal charge and the discharge of the storage battery train after the previous equivalent charge is completed. The charge control method characterized by including the step which determines that the said equal charge of the said storage battery row | line | column was completed when the ratio with the integrated value of electric current becomes a predetermined value.
The charge control method according to claim 6, wherein
In the constant voltage charging period in which the control device charges the storage battery train with a constant voltage in the equal charge, the storage battery is reduced when the charging current of the storage battery array decreases to a predetermined value. A charge control method comprising: determining that the equal charge of the column is completed.
The charge control method according to claim 8,
The equal charge is performed by a constant current-constant voltage charging method in which charging of the storage battery train is started by a constant current, and the storage battery train is charged by a constant voltage after the voltage of the storage battery train reaches a predetermined voltage. A charge control method characterized by the above.
The charge control method according to claim 8,
The equal charge is performed by a constant power-constant voltage charging method in which charging of the storage battery train is started by constant power and the storage battery train is charged by constant voltage after the voltage of the storage battery row reaches a predetermined voltage. A charge control method characterized by the above.