JP2019184374A - Power storage system - Google Patents

Abstract

To provide a power storage system with which, while reusing a large number of storage batteries, it is possible to efficiently replace the storage batteries.SOLUTION: Provided is a power storage system including a plurality of battery packs each accommodating secondary battery cells, with at least one of the plurality of battery packs replaced with other battery packs on the occasion of prescribed maintenance work. A control circuit 100 extracts a candidate for the battery pack to be replaced on the next occasion of maintenance work from among the plurality of battery packs on the basis of the remaining life of each of the plurality of battery packs, and replacing, on the basis of the result of comparison of the number of extracted battery packs with a prescribed number, a degree of a load applied to a prescribed battery pack among the plurality of battery packs so that the number of battery packs to be replaced on the next occasion of maintenance work equals the prescribed number, thereby making it possible to adjust remaining lives of the battery packs.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage system that reuses a large number of used storage batteries.

  To realize a decarbonized society, for example, a shift from petrochemical engine vehicles to electric vehicles with low carbon dioxide emissions is progressing. On the other hand, what is important in this process is how to effectively use a large amount of used storage batteries.

  One of the industrial fields where used storage batteries are reused is the field of building management. In this field, many used storage batteries that have been used for electric vehicles and then become worn out of specification, such as solar power generation and nighttime power storage systems, are reused as elevator driving assistance and lighting. It is expected to be used for assistance and assistance for air conditioners.

  In storage systems that recycle a large number of used storage batteries, it is important to note that the battery characteristics of each storage battery differ, so it is important to know the characteristics and capacity of each battery before replacing the storage battery. It is necessary to manage properly. For example, in Patent Document 1, in a secondary battery having two different characteristics, the battery characteristics, the number, and the like are stored in a memory, and each of the two based on the outputs of an ammeter and a voltmeter connected to the assembled battery. Describes a technology that calculates the deterioration rate and remaining life of a secondary battery and outputs a detection signal if it is less than the specified value, or equalizes the voltage of a secondary battery with two different characteristics based on this result. ing.

  Patent Document 2 includes a deterioration determination unit and a remaining life estimation unit. The deterioration determination unit determines a deterioration degree of the battery module and extracts a battery module to be replaced. Even if there is no problem with the deterioration state, the remaining life estimation is performed. Describes a technique for extracting a battery module whose remaining life calculated in the section is smaller than a set value as an object to be replaced.

JP 2013-246109 A International Publication No. 2011-125213

  In a power storage system that reuses a large number of used storage batteries, there is a problem that the storage batteries must be frequently replaced according to the difference in the life of each storage battery. Patent Document 1 merely discloses a technique related to leveling for extending the life of assembled batteries having different remaining lives, and there is no consideration for improvement of this problem. Patent Document 2 also discloses a technique for extracting candidate storage batteries to be exchanged, and is the same. An object of this invention is to provide the electrical storage system which can replace | exchange a storage battery efficiently, utilizing many storage batteries.

  In order to achieve the above object, the present invention includes a plurality of battery packs each accommodating a cell of a secondary battery, and includes a control circuit for the plurality of battery packs in a power storage system in which maintenance work is periodically performed. The control circuit extracts a candidate battery pack to be replaced in the next maintenance operation from the plurality of battery packs based on the remaining life of each of the plurality of battery packs, and the extracted Based on the comparison result between the number of battery packs and the specified number, the predetermined number of battery packs among the plurality of battery packs is set such that the number of battery packs to be replaced at the time of the next maintenance work becomes the specified number. The remaining life of the battery pack can be adjusted by changing the degree of load applied to the battery pack.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage system which can replace | exchange a storage battery efficiently can be provided, utilizing many storage batteries.

FIG. 1 is a block diagram according to an embodiment of a power storage system of the present invention. It is an example of the flowchart explaining the process which assists replacement | exchange of a battery pack by the control circuit of the electrical storage system of FIG. It is a curve of the charge characteristic of a secondary battery. It is a curve of the discharge characteristic of a secondary battery. It is a front view of the housing | casing of the electrical storage system of FIG. It is a front view which shows the storage structure of the some battery pack in one battery module. FIG. 4 is a block diagram according to a second embodiment of the power storage system of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram according to an embodiment of a power storage system of the present invention. The power storage system includes a plurality of battery modules 1 and a control circuit 100 that controls the plurality of battery modules. Each of the plurality of battery modules accommodates a plurality of battery packs. Reference numerals 2a, 2b, 2c, and 2d each represent one battery pack in the battery module. The battery pack is composed of a plurality of secondary battery cells. The control circuit 100 manages a plurality of battery packs for each battery module.

  The battery packs 2a, 2b, 2c, 2d of the plurality of battery modules are connected in series with each other via the switches 3a, 3b, 3c, 3d. The number of battery packs connected in series is not limited to “4” as shown in FIG. In each of the plurality of battery modules, the sensors 5a, 5b, 5c, and 5d are connected to the battery packs 2a, 2b, 2c, and 2d as illustrated. The sensor detects parameters related to the operating state of the battery pack, such as voltage, number of times of charging / discharging, temperature, and the like from the battery pack. The sensor is connected to the control circuit 100. The control circuit 100 collects measurement values from the sensors 5a, 5b, 5c, and 5d and monitors the state of the battery pack.

  Reference numeral 6 denotes an ammeter that measures the current flowing through the wiring 102 that connects the plurality of battery packs 2a, 2b, 2c, and 2d in series. Reference numeral 104 denotes a wiring connected in parallel to the wiring 102 and connected to the switches 4a, 4b, 4c, and 4d. Each of the plurality of switches 3a, 3b, 3c, 3d, 4a, 4b, 4c, and 4d is opened and closed by the control circuit 100.

  The control circuit 100 can select a predetermined battery pack by a switch circuit. For example, when the control circuit 100 turns off the switches 3a, 4b, 4c, and 4d and turns on the other switches, a configuration in which the battery packs 2b, 2c, and 2d are connected in series except for the battery pack 2a can be realized. . Similarly, if the control circuit 100 turns off the switches 3b, 4a, 4c, and 4d and turns on the other switches, the battery pack 2b is removed and the battery packs 2a, 2c, and 2d are connected in series. it can. By controlling the on / off of the switches 3a to 3d and 4a to 4d as described above, the combination of a plurality of battery packs used for charging and discharging can be changed.

  Reference numerals 7a to 7d are temperature regulators that exist in each of the plurality of battery modules 1 and can adjust the temperature in the battery modules (environment temperature of the battery pack).

  The control circuit 100 may be configured by a computer. The control circuit 100 includes computer hardware resources, for example, a controller such as a CPU, a memory, a storage device such as an HDD, a display device, an input device, and a communication device, and further includes an OS and a battery pack that are software resources. An application program for controlling Reference numeral 8 is a monitoring module that monitors the state of the battery pack, reference numeral 10 is an estimation module that estimates the remaining life of the battery pack, reference numeral 11 is an extraction module that extracts a predetermined battery pack from a plurality of battery packs, reference numeral An adjustment module 12 can adjust the remaining life of the battery pack. These modules are realized by the controller executing software resources. Reference numeral 9 denotes a storage module including a memory and / or a storage device. A module may be rephrased as a part, means, or element.

  The measurement information of the sensors 5a to 5d and the ammeter 6 is sent to the monitoring module 8. Based on the measurement information, the monitoring module 8 manages the state of the battery pack, such as the capacity of each of the battery packs 2a to 2d and the degree of deterioration. The monitoring module 8 captures measurement information for each predetermined sampling period, and records the measurement information and the management result based on the measurement information in the storage module 9. Based on the information recorded in the storage module 9, the estimation module 10 calculates the remaining lifetime of each of the battery packs 2a, 2b, 2c, 2d and records this in the storage module 9.

  The extraction module 11 refers to the calculated value of the remaining life of the storage module 9 and extracts a battery pack to be replaced at the next maintenance work of the power storage system. The maintenance work may be performed every predetermined date, for example, periodically. The extraction module 11 records the extracted battery pack information in the storage module 9. The adjustment module 12 determines one or a plurality of battery packs whose remaining life should be adjusted based on the extracted information of the storage module 9. The adjustment module 12 can set which battery pack is connected in series by turning on / off the switches 3a to 3d, 4a to 4d, and accommodates the battery pack by controlling the temperature regulators 7a to 7d By controlling the temperature environment of the module 1, the remaining life of a predetermined battery pack can be adjusted, that is, the remaining life can be extended or shortened.

  Next, battery pack replacement processing executed by the power storage system will be described. In a system that uses a large number of used battery packs, the remaining life of each of the plurality of battery packs varies from one battery pack to another. Therefore, it is preferable to replace this battery pack with another battery pack that has a remaining life whenever a battery pack whose life has expired is generated. However, there is a problem that replacement of the battery pack occurs frequently, increasing the burden of replacement work and increasing the replacement cost. On the other hand, even if the battery pack is replaced periodically, the number of battery packs to be replaced fluctuates every time the replacement work is performed, and when the number of battery packs is small, the replacement effort is wasted. When there are many, the replacement work cannot be made efficient because the replacement labor is insufficient.

  Therefore, the above-described power storage system is replaced even when maintenance work is regularly performed, and one or more of the plurality of battery packs are replaced with another battery pack every predetermined date or periodically. By adjusting the remaining life of the battery to be replaced, the battery pack can be replaced efficiently so that the number of battery packs to be replaced becomes a predetermined specified number when replacing the battery pack. It is intended to be implemented. The above-mentioned “specified number” may be determined in advance from the viewpoint of maintaining the performance of the power storage system and not increasing the burden of replacement work. The adjustment module 12 described above controls the remaining life of the battery pack. It is possible to extend or shorten the remaining life of the battery pack by changing the degree or degree of load applied to the battery pack, that is, increasing or suppressing the degree of load. The load applied to the battery pack is, for example, the number of times of charging / discharging and the temperature of the environment (battery module) in which the battery pack is placed. In addition, the timing which replaces | exchanges a battery pack can be match | combined with the periodic inspection of the elevator of a building to which an electrical storage system is applied, for example.

  The worker replaces the battery pack extracted as a replacement candidate at the previous inspection during the maintenance of the power storage system. When the battery pack is replaced, the power storage system further extracts a battery pack to be replaced at the next maintenance.

  FIG. 2 is a flowchart illustrating a process for supporting the replacement of the battery pack by the control circuit 100. For example, when the battery pack is to be replaced, the control circuit 100 may start the flowchart by the input of the worker. Based on the measurement information recorded in the storage module 9, the monitoring module 8 calculates the current capacity (capacity that can be fully charged) for all the battery packs (S101). This calculation requires data on the initial capacity of the battery pack, which may be stored in the storage module 9. The initial capacity data may be a nominal value guaranteed by the manufacturer from the model of the battery pack, or a value measured from a new battery pack.

  The estimation module 10 estimates the remaining life of all battery packs. Therefore, the estimation module 10 calculates the battery pack deterioration degree d based on the current capacity and the initial capacity of the battery pack. The battery pack that has reached the deterioration level set as the replacement standard is replaced. The remaining life of the battery pack is a period until the battery pack reaches the degree of deterioration set as a replacement standard.

  The deterioration of the battery is affected by various factors. As can be seen from the following equation 1, the influence of the environmental temperature T, the operation time t, and the number of times of charging / discharging n is large.

関数fは温度、稼動時間と劣化との関係式を表し、関数gは温度、充放電回数と劣化との関係式を表す。また、d0(t0)は時間t0での劣化度を表す。推定モジュール10は、電池パックの使用履歴に係る充放電回数及び稼働時間を式１に適用し、さらに、電池パックの交換を行うための劣化度として規定値を式１に適用して、その規定値に達するまでの将来時間、すなわち、電池パックの残存寿命を推定する。

The function f represents a relational expression between temperature, operating time and deterioration, and the function g represents a relational expression between temperature, charge / discharge frequency and deterioration. D0 (t0) represents the degree of deterioration at time t0. The estimation module 10 applies the charging / discharging frequency and operating time related to the use history of the battery pack to Equation 1, and further applies the specified value to Equation 1 as the degree of deterioration for replacing the battery pack. The future time until the value is reached, that is, the remaining life of the battery pack is estimated.

  Based on the estimated remaining life (or battery capacity) of all the battery packs, the extraction module 11 extracts battery pack candidates to be replaced during the next maintenance (S102). Predetermining the battery pack to be replaced at the time of the next maintenance means that the power storage system that reuses many used battery packs can be operated stably and the replacement of battery packs can be made more efficient. It is effective for compatibility.

  The extraction module 11 compares the number of battery pack candidates to be replaced at the time of the next maintenance with the prescribed number described above (S103). If the number of candidates is smaller than the specified number, the extraction module 11 makes an affirmative determination in S103 and proceeds to S104. The extraction module 11 adds the battery packs as replacement candidates from the battery packs that have not been selected as replacement candidates in order of decreasing remaining life until the specified number is reached (S104). The replacement battery pack that has been added does not reach the level of deterioration that should be replaced by the next maintenance in the current usage state, so it is necessary to change the degree of load applied to the battery pack to promote battery pack consumption. There is. Therefore, the extraction module 11 sends a command for promoting the consumption of the newly added battery pack as a replacement candidate to the adjustment module 12 (S105) and ends the flowchart.

  The adjustment module 12 increases, accelerates, increases, etc. the degree of load applied to the battery pack added as a replacement candidate, for example, increases the number of times of charging / discharging and / or increases the environmental temperature of the battery pack, Ensure that the remaining life of the pack is digested quickly. The adjustment module 12 controls on / off of the above-described switch, and while the battery pack added to the replacement candidate is connected to the charge / discharge circuit, other battery packs are removed from the charge / discharge circuit, excluded, etc. The number of times of charging / discharging the battery pack added to the replacement candidate is relatively increased, and / or the cooling frequency of the temperature regulators 7a to 7d of the module 1 to which the battery pack added to the replacement candidate belongs is reduced. The battery pack is consumed to the extent that it should be replaced by the next maintenance. The battery pack is consumed and deteriorated as the number of times of charging / discharging increases and / or as the environmental temperature increases.

  As described above, the adjustment module 12 can adjust and manage the remaining life of the battery pack by promoting the consumption of the battery pack. If consumption of a battery pack that is not a replacement candidate is suppressed instead of promoting consumption of a battery pack that is newly added as a replacement candidate, there is no adverse effect on the entire power storage system. In addition, since the remaining life of a battery pack changes with the conditions in which a battery pack is used, it is normal that the number of candidates does not become a regulation number.

  If the number of candidates is greater than the specified number, the extraction module 11 makes a negative determination in S103 and proceeds to S106. Since the number of battery packs extracted or selected as replacement candidates is larger than the specified number, the extraction module 11 excludes battery packs from the replacement candidates until the number of candidates reaches the specified number in the order of longer remaining life ( S106). If the excluded battery pack continues to be used with the current conditions until the next maintenance, the deterioration proceeds beyond the specified degree of deterioration. The extraction module 11 sends a command to the adjustment module 12 to suppress the consumption of the battery pack removed from the replacement candidate (S105), and the flowchart is ended.

  In response to this suppression command, the adjustment module 12 controls the ON / OFF of the above-described switch, for example, to suppress, reduce or alleviate the load on the battery pack removed from the replacement candidate, and is added to the replacement candidate. The number of times of charging / discharging the battery pack is decreased and / or the cooling frequency of the temperature regulators 7a to 7d of the module 1 to which the battery pack removed from the replacement candidate belongs is increased so that the battery pack can be replaced before the next maintenance. Make sure that the battery pack does not run out in the middle so that it does not wear out. This battery pack becomes a candidate for replacement at the next maintenance. In this manner, the control circuit 100 ensures that the number of battery packs to be replaced becomes a specified number during maintenance of the power storage system. If the number of candidates is equal to the specified number in S103, the control system 100 ends the flowchart without proceeding to S104 and S106. According to the flowchart shown in FIG. 2, since the number of battery packs to be replaced at the time of the next maintenance is set to a predetermined number, the battery pack replacement operation can be made more efficient. If the number of battery packs to be replaced is small, the human resources and equipment prepared for replacement will be wasted. On the other hand, if the number of battery packs to be replaced is large, the human resources and equipment prepared for replacement will be insufficient. There were problems such as having to add replacement work.

  Here, the attributes of the secondary battery will be described. Fig. 3 shows the curve of the charging characteristics of the secondary battery, and Fig. 4 shows the curve of the discharging characteristics of the secondary battery. The horizontal axis is the charging rate with respect to the initial capacity, and the vertical axis is the voltage. This is a case where the solid line is in the initial state and the dotted line is in a degraded state. As the battery deteriorates, the charging rate at the time of full charge is lowered from the initial charged state, and the battery life is shortened. The degree of deterioration of the battery can also be understood from the charging rate at the time of full charge. The voltage difference between the charge curve and the discharge curve becomes larger as the voltage difference deteriorates compared to the initial state. Therefore, the deterioration degree of the battery can be determined also by the voltage difference.

  In order to stabilize power supply, a large-capacity power storage system is required. In a large-capacity power storage system, there are many battery modules and battery packs. In order for the worker to efficiently perform the battery replacement work, it is preferable that the worker can recognize the battery pack as the replacement candidate without spending time. 5 and 6 show an example of a system for informing a battery pack that is a replacement candidate. FIG. 5 is a front view of the housing of the power storage system. There are two cases, and one case is configured with four battery modules. A power storage system is configured by two housings. Reference numerals 30-37 denote battery modules, reference numerals 30a-37a denote front doors of the battery modules, and reference numerals 30b-37b denote display portions provided on the front doors. The control system 100 turns on the display unit (31b, 37b) of the battery module having the battery pack that is the replacement candidate.

  FIG. 6 is a front view showing a housing structure for a plurality of battery packs in one battery module. When the battery module door is opened, the storage structure is exposed. In FIG. 6, reference numeral 40-51 denotes a battery pack, reference numeral 40a-51a denotes a small housing of the battery pack, and reference numeral 40b-51b denotes a display unit (display output device) of the battery pack. The control circuit 100 informs the operator of the battery pack that is the replacement candidate by lighting the display (40b, 50b) of the battery pack that is the replacement candidate. The display unit may be any lighting display such as a liquid crystal panel, a pilot lamp, and an LED that can be easily understood by the operator. Due to the presence of the display unit, the worker can quickly find the battery pack to be replaced in a large number of battery packs.

  The worker can visually recognize the replacement candidate battery pack through the display unit of the battery module and the display unit of the battery pack. When the operator finishes replacing the battery pack that was the replacement candidate, the control circuit 100 turns off the display regarding the replaced battery pack, displays the battery pack display section that is the replacement candidate for the next maintenance, and the battery pack. The display of the battery module having the pack is turned on. Note that the control circuit 100 may turn on the display unit so that the battery packs that have been removed from the replacement candidates and the battery packs that have been added to the replacement candidates can be distinguished according to the flowchart of FIG.

  FIG. 7 shows a block diagram according to the second embodiment of the power storage system of the present invention. The storage battery system according to the second embodiment is different from the embodiment of FIG. 1 in that the battery packs 2e, 2f, and 2g are connected in parallel. The number of battery packs is not limited.

  Sensors 5e, 5f, and 5g that detect current, the number of times of charge and discharge, temperature, and the like are connected to each battery pack. The voltmeter 21 measures the voltage applied to the battery pack. Switches 3e, 3f, 3g are connected to each battery pack. When the switch 3e is turned off and the other switches are turned on, the battery pack 2e is removed and the two battery packs 2f and 2g are connected in parallel. Similarly, if the switches 3e and 3f are turned off and the other switches are turned on, the battery packs 2e and 2f are detached and only the battery pack 2g is connected.

  Similarly to the power storage system in FIG. 1, the battery pack to be operated by the power storage system can be changed by the on / off control of the switches 3e to 3g by the power storage system in FIG. The extraction module 11 extracts a replacement candidate battery pack based on the data of the sensors 5e to 5g, the voltmeter 21, and the data stored in the storage module 9. The adjustment module 12 controls on / off of the switches 3e to 3g to increase or decrease the number of times of charging / discharging the extracted battery pack, or to increase or decrease the cooling frequency of the temperature regulators 7e to 7g with respect to the extracted battery pack. Adjust the life of the battery pack.

  The power storage system may include a structure in which a plurality of battery packs are connected in series and in parallel. The specified number described above may be a value having a predetermined width other than the specific value. In the above-described embodiment, the power storage system that uses a used battery pack has been described. However, even in a power storage system that uses a large number of new battery packs, the usage status of the battery pack varies from battery pack to battery pack. The present invention can be applied to the case where battery packs whose lifetime has been reduced continuously occur little by little.

  In the above-described embodiment, when the number of candidates is smaller than the specified number, the extraction module 11 extracts the battery packs from the battery packs that are not selected as replacement candidates in the order of short remaining life. However, it is easier to replace the battery pack if a battery pack that is relatively close to the replacement candidate battery pack is added as a replacement candidate. Therefore, based on an indicator that integrates two parameters: short remaining life (need to replace the battery pack) and close relative distance (ease of work when replacing the battery pack). The battery pack to be added as a replacement candidate may be determined. For this purpose, the control circuit 100 only needs to manage the position information of the battery pack. In the above-described embodiment, the battery pack has been described as a reuse product, but the cell of the secondary battery may be a reuse product. The above-described embodiments are not intended to limit the present invention, and may be modified or improved within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Battery module, 2 ... Battery pack, 6 ... Ammeter, 7 ... Temperature controller, 8 ... Monitoring module, 12 ... Adjustment module

Claims (5)

A plurality of battery packs each accommodating a secondary battery cell;
In power storage systems where maintenance work is carried out regularly,
A control circuit for the plurality of battery packs;
The control circuit includes:
Based on the remaining life of each of the plurality of battery packs, extract candidate battery packs to be replaced during maintenance work from the plurality of battery packs,
Based on the comparison result between the number of battery packs extracted and the specified number, the number of battery packs to be replaced at the time of the next maintenance operation is the specified number. By changing the degree of load applied to a given battery pack, the remaining life of the battery pack can be adjusted.
A power storage system characterized by that. A sensor for measuring the state of the plurality of battery packs;
The control circuit includes:
Based on the signal from the sensor, the remaining life of each of the plurality of battery packs is estimated,
Comparing the number of battery packs extracted as candidates with the specified number;
If the number of battery packs extracted as candidates is smaller than the specified number, add battery packs other than the battery packs extracted as candidates to candidates to be replaced in the next maintenance work,
The degree of load applied to the battery pack added to the candidate is increased, and the digestion of the lifetime of the battery pack is promoted.
The power storage system according to claim 1. A sensor for measuring the state of the plurality of battery packs;
The control circuit includes:
Based on the signal from the sensor, the remaining life of each of the plurality of battery packs is estimated,
Comparing the number of battery packs extracted as candidates with the specified number;
If the number of battery packs extracted as candidates is larger than the specified number, some of the battery packs extracted as candidates are removed from candidates to be replaced in the next maintenance work,
The degree of load applied to the battery pack removed from the candidate is suppressed, and digestion of the life of the battery pack is suppressed.
The power storage system according to claim 1.   4. The output device according to claim 1, further comprising: an output device that distinguishes from other battery packs and notifies battery pack candidates to be replaced in the next maintenance work from among the plurality of battery packs. 5. The electrical storage system of Claim 1.   4. The power storage system according to claim 1, wherein each of the cells of the secondary battery includes a reused product that has been used. 5.

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