JP2013106506A - Power storage device and power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device that can reduce a secular deterioration (shelf deterioration) of a storage battery.SOLUTION: A power storage device 20 includes a storage battery 22 and a control section 23 for performing charge control of the storage battery 22. When the storage battery 22 is required to be charged with a first predetermined amount in a first constant period, the control section 23 controls charging at a first rate satisfying the following expression (1) and delays a start timing of charging beyond a start timing of the first constant period. v1>c1/t1 ... (1), where v1 is the first rate, c1 is the first predetermined amount, and t1 is the first constant period of time length.

Description

  The present invention relates to a power storage device, and more particularly to a technique for suppressing the deterioration of a storage battery included in the power storage device and extending the life of the power storage device. The present invention also relates to a power supply system including a power storage device having a long lifetime.

  A storage battery (for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery) included in the power storage device deteriorates. As deterioration of a storage battery, deterioration due to charge / discharge use (cycle deterioration) and deterioration that progresses with time (aging deterioration: sometimes referred to as storage deterioration) are known. Note that the aging deterioration occurs not only when the storage battery is not used, but also when it is used (during charging or discharging). Conventionally, it has been desired to extend the life of a power storage device by suppressing deterioration of the storage battery.

  Patent Document 1 discloses a discharge control device for a storage battery that extends the life of the storage battery. Based on the discharge depth detected by the discharge depth detection means, the control means provided in this discharge control device controls the operation of the power-supplied device so as not to exceed the standard discharge depth that guarantees the life of the storage battery. Thereby, in the said discharge control apparatus, the influence on the lifetime of a storage battery by overdischarge can be eliminated. In addition, although patent document 1 discloses a measure for extending the life when discharging the storage battery, it does not disclose a measure for extending the life when charging the storage battery.

Japanese Patent Laid-Open No. 10-243572

  In view of the above points, an object of the present invention is to provide a power storage device that can suppress deterioration of a storage battery and extend its life. Another object of the present invention is to provide a power supply system including such a power storage device and excellent in cost merit.

In order to achieve the above object, a power storage device according to the present invention is a power storage device including a storage battery and a control unit that performs control related to charging of the storage battery, wherein the control unit has a first constant on the storage battery. When it is necessary to charge the first predetermined amount in a period, charging is performed at a first speed that satisfies the following expression (1), and the start timing of the charging is set to the first fixed period. It has a configuration (first configuration) delayed from the start timing.
v1> c1 / t1 (1)
v1: First speed c1: First predetermined amount t1: Time length of a first fixed period

  According to this configuration, the aging of the storage battery (when compared to the case where the first predetermined amount is charged at a constant charging rate (v = c1 / t1) during the first fixed period (conventional configuration) ( Storage degradation) can be reduced. For this reason, according to this structure, deterioration of the storage battery at the time of charge can be suppressed, and the lifetime of an electrical storage apparatus can be extended.

  In the power storage device having the first configuration, the control unit preferably has a configuration (second configuration) in which the end timing of charging is substantially the same as the end timing of the first predetermined period. According to this configuration, the effect of reducing aging deterioration of the storage battery can be increased.

  In the power storage device having the first or second configuration, the control unit determines whether the deterioration progress of the storage battery, which increases or decreases according to a charging speed, is the first predetermined amount over the first predetermined period. It is preferable that the first speed is set (third structure) so as to be smaller than when charging at a uniform speed (= c1 / t1). The progress of deterioration of the storage battery is a combination of the progress of cycle deterioration and the progress of aging deterioration. According to this configuration, charging can be performed at an appropriate speed, and deterioration of the storage battery can be appropriately suppressed.

In the power storage device having any one of the first to third configurations, the control unit is provided to perform control related to discharging of the storage battery in addition to control related to charging of the storage battery, and the control unit includes: When the second predetermined amount of discharge needs to be performed from the storage battery in a second fixed period, the discharge is performed at a second rate that satisfies the following expression (2), and the end timing of the discharge It is preferable that (4th configuration) be set earlier than the end timing of the second predetermined period.
v2> c2 / t2 (2)
v2: Second speed c2: Second predetermined amount t2: Time length of the second fixed period

  According to this configuration, the aging of the storage battery is reduced compared to the case where the second predetermined amount is discharged at a constant discharge rate (v = c2 / t2) during the second fixed period (conventional configuration). It can be reduced. That is, in this configuration, deterioration of the storage battery can be suppressed during charging and discharging, and the life of the power storage device can be easily extended.

  In the power storage device of the fourth configuration, it is preferable that the control unit has a configuration (fifth configuration) in which the start timing of the discharge is substantially the same as the start timing of the second fixed period. According to this configuration, the effect of reducing aging deterioration of the storage battery can be increased.

  In the power storage device having the fourth or fifth configuration, the control unit may cause the deterioration degree of the storage battery, which increases or decreases depending on a discharge speed, to change the second predetermined amount over the second predetermined period. It is preferable that the second speed is set (sixth structure) so as to be smaller than when discharging at a uniform speed (= c2 / t2). According to this configuration, discharging can be performed at an appropriate speed, and deterioration of the storage battery can be appropriately suppressed.

  In the power storage device having any one of the first to sixth configurations, a power conversion unit electrically connected to the storage battery is provided, and the control unit has a charge / discharge speed determined by a rating of the power conversion unit. It is preferable that the first speed and the second speed be set below the upper limit value (seventh structure).

In order to achieve the above object, a power storage device according to the present invention is a power storage device including a storage battery and a control unit that performs control related to discharging of the storage battery, and the second storage unit is connected to the storage battery for a second period of time from the storage battery. When it is necessary to perform a predetermined amount of discharge, discharge is performed at a second speed that satisfies the following expression (2), and the discharge end timing is made earlier than the end timing of the second predetermined period. This is a configuration (eighth configuration).
v2> c2 / t2 (2)
v2: Second speed c2: Second predetermined amount t2: Time length of the second fixed period

  According to this configuration, the aging of the storage battery (when the second predetermined amount is charged at a constant charging speed (v = c2 / t2) during the second fixed period (conventional configuration) ( Storage degradation) can be reduced. For this reason, according to this structure, deterioration of the storage battery at the time of discharge can be suppressed, and the lifetime of an electrical storage apparatus can be extended.

  In the power storage device of the eighth configuration, it is preferable that the control unit has a configuration (a ninth configuration) in which the start timing of the discharge is substantially the same as the start timing of the second fixed period. According to this configuration, the effect of reducing aging deterioration of the storage battery can be increased.

  In order to achieve the above object, a power supply system of the present invention is provided with a power supply unit capable of supplying power to an external load, and capable of charging power from the power supply unit, and discharging the power to the external load. It is possible to provide a configuration (tenth configuration) including any of the first to ninth power storage devices.

  In this configuration, the power supply system is configured by using the power storage device that can reduce the deterioration of the storage battery, and the life of the power supply system can be expected to be extended.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage apparatus which can suppress deterioration of a storage battery and can achieve a lifetime can be provided. Further, according to the present invention, it is possible to provide a power supply system that includes such a power storage device and is excellent in cost merit.

The block diagram which shows schematic structure of the power supply system which concerns on one Embodiment of this invention. The flowchart which shows an example of the lifetime extension control at the time of the charge performed in the electrical storage apparatus of this embodiment The flowchart which shows an example of the lifetime extension control at the time of discharge performed in the electrical storage apparatus of this embodiment The graph which shows an example of charging / discharging profile and SOC transition to which charging / discharging control of this embodiment was applied The graph which shows an example of charging / discharging profile and SOC transition to which charging / discharging control of the comparative example was applied Graph for explaining cycle deterioration characteristics Graph to explain the aging (storage deterioration) characteristics Graph to explain the upper limit of charge / discharge rate

  Hereinafter, embodiments of a power storage device and a power supply system of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a power supply system 1 according to an embodiment of the present invention. In FIG. 1, thick lines indicate power lines and thin lines indicate signal lines. As shown in FIG. 1, the power supply system 1 includes a power supply unit 10 and a power storage device 20.

  The power supply unit 10 supplies power to the external load and the power storage device 20. Examples of the power supply unit 10 include a commercial AC power supply (power system), a natural energy power generation device that generates power using natural energy, and the like. Examples of the natural energy power generation device include a solar power generation device that generates power using sunlight and a wind power generation device that generates power using wind power. The power supply unit 10 may include a plurality of power supply sources such as a configuration including both a commercial AC power supply and a natural energy power generation device.

  The power storage device 20 can store power supplied from the power supply unit 10 and can supply power to an external load. The power stored in the power storage device 20 may be configured to be supplied to the power system. The power storage device 20 includes a power conversion unit (PCS: Power Conditioning System) 21, a storage battery 22, and a controller 23.

  The PCS 21 converts the power supplied from the power supply unit 10 into appropriate power and outputs it to the storage battery 22. Moreover, PCS21 converts the electric power supplied from the storage battery 22 into appropriate electric power, and outputs it to an external load (in some cases, an electric power system). The PCS 21 includes power conversion means selected from various converters and inverters according to the configuration of the power supply unit 10. For example, when the power supply unit 10 includes a commercial AC power supply, the PCS 21 may include a bidirectional AC / DC converter. When the power supply unit 10 includes a solar power generation device, the PCS 21 may include a DC / DC converter.

  The storage battery 22 may be a chargeable / dischargeable secondary battery such as a lithium ion battery or a nickel metal hydride battery, and the type thereof may be selected as appropriate. The storage battery 22 may be composed of one storage battery cell, or may be a battery pack in which a plurality of storage battery cells are connected in series, parallel, or series-parallel. Further, the storage battery 22 may have a configuration in which a plurality of the aforementioned assembled batteries are connected in series, in parallel, or in series-parallel. The storage battery 22 outputs information related to the battery (for example, SOC described later) to the controller 23.

  The controller 23 outputs a command signal related to charging / discharging of the storage battery 22 to the PCS 21. The PCS 21 converts the supplied power into appropriate power based on the command and outputs the converted power. The controller 23 is provided with a non-volatile memory 23a that stores information on the charging speed and discharging speed of the storage battery 22, for example. The controller 23 is an example of a control unit of the present invention.

  The power storage device 20 is characterized in that the controller 23 controls charging / discharging so that deterioration of the storage battery 22 is suppressed. This will be described below.

  FIG. 2 is a flowchart illustrating an example of the life extension control during charging, which is executed in the power storage device 20 of the present embodiment. The controller 23 determines a charging condition based on the input charging command (a command input from a controller provided outside the power storage device 20 or inside the power storage device 20) (step S1). As the charging command input to the controller 23, for example, a command “charge a predetermined amount (hereinafter referred to as a first predetermined amount) within a predetermined period (hereinafter referred to as a first predetermined period)” is given. Can be mentioned.

The controller 23 performs charging at a first speed that satisfies the following expression (1), and the charging condition is set so that the timing at which charging is started is delayed from the timing at which the first fixed period starts. To decide. In this case, it is preferable that the controller 23 determines the charging condition so that the charging end timing is substantially the same as the end timing of the first predetermined period. The details of the charging condition determination method will be described later.
v1> c1 / t1 (1)
v1: Charge rate (charge rate)
c1; first predetermined amount (predetermined charge amount given by the charge command)
t1: Time length of the first fixed period (time length of the fixed period given by the charge command)

  The controller 23 starts time measurement in synchronization with the start timing of the first certain period (step S2). When the start timing of the first fixed period starts immediately after receiving the charge command, a process of starting time measurement may be performed in parallel with the determination process of the charge condition.

  The controller 23 monitors whether or not a predetermined period has elapsed from the start of time measurement in step S2 (step S3). This predetermined period is a period (one element of the charging condition) determined in step S1, and corresponds to a waiting time from the start timing of the first certain period until the charging is started.

  When a predetermined period has elapsed (Yes in step S3), the controller 23 issues a charge start command to the PCS 21. Thereby, charge of the storage battery 22 is started (step S4). The charging rate at this time is determined in step S1. When charging of the storage battery 22 is started, the controller 23 monitors whether or not the first predetermined amount of charging that has been instructed has been performed (step S5). The determination as to whether or not the first predetermined amount of charge has been performed can be made based on, for example, the time from the start of charging. When the first predetermined amount of charging is performed, the controller 23 controls the PCS 21 to finish charging the storage battery 22.

  FIG. 3 is a flowchart illustrating an example of the life extension control at the time of discharging, which is executed in the power storage device 20 of the present embodiment. The controller 23 determines the discharge condition based on the input discharge command (command input from a controller provided outside the power storage device 20 or inside the power storage device 20) (step S11). As a discharge command input to the controller 23, for example, a command “discharge a predetermined amount (hereinafter referred to as a second predetermined amount) within a predetermined period (hereinafter referred to as a second predetermined period)” is given. Can be mentioned.

The controller 23 performs the discharge at the second speed that satisfies the following expression (2), and determines the discharge condition so that the end timing of the discharge is earlier than the end timing of the second fixed period. In this case, the controller 23 preferably determines the discharge conditions so that the discharge start timing is substantially the same as the start timing of the second fixed period. The details of the method for determining the discharge conditions will be described later.
v2> c2 / t2 (2)
v2: Discharge rate (discharge rate)
c2; second predetermined amount (predetermined discharge amount given by the discharge command)
t2: Time length of the second fixed period (time length of the fixed period given by the discharge command)

  When the discharge condition is determined, the controller 23 determines whether or not it is time to start discharging (step S12). The timing for starting the discharge is preferably as close as possible to the start timing of the second fixed period, but may be slightly delayed from the start timing of the second fixed period as the case may be. If it is determined that it is time to start discharge, the controller 23 issues a discharge start command to the PCS 21. Thereby, the discharge from the storage battery 22 is started (step S13). The discharge rate at this time is determined in step S11.

  When the discharge from the storage battery 22 is started, the controller 23 monitors whether or not a second predetermined amount of discharge has been received (step S14). The determination of whether or not the second predetermined amount of discharge has been performed can be made based on, for example, the time from the start of discharge. When the second predetermined amount of discharge is performed, the controller 23 controls the PCS 21 to end the discharge from the storage battery 22.

  An effect when charge / discharge (charge and discharge) control is performed according to the flowcharts of FIGS. 2 and 3 will be described. FIG. 4 is a graph showing an example of the charge / discharge profile and the SOC transition to which the charge / discharge control (long life control) of the present embodiment is applied. 4A shows the charge / discharge profile, and FIG. 4B shows the SOC transition. FIG. 5 is a graph showing an example of the charge / discharge profile and SOC transition to which the charge / discharge control of the comparative example (normal form before the present invention) is applied. FIG. 5A shows the charge / discharge profile, and FIG. 5B shows the SOC transition.

  The SOC is an index indicating the state of charge of the battery, and is represented by the ratio (percentage) of the dischargeable capacity (remaining capacity) to the full charge capacity. The SOC of the storage battery 22 is obtained from, for example, an integrated value of charge / discharge current flowing through the storage battery 22. Further, the SOC of the storage battery 22 can also be obtained by referring to a calculation formula or table showing a relationship between the open circuit voltage (OCV) of the storage battery 22 and the SOC determined in advance.

  In the graphs shown in FIG. 4A and FIG. 5A, the horizontal axis is time, and the vertical axis is power during charging or discharging. As shown in FIG. 5 (a), in the control of the comparative example, when it is necessary to charge the first predetermined amount (10 kWh) in the first fixed period (1 hour), during the first fixed period The battery is charged with uniform power (10 kW). This equal power corresponds to a value obtained by dividing the first predetermined amount (10 kWh) by the time length (1 hour) of the first fixed period.

  On the other hand, in the charging control of the present embodiment, as shown in FIG. 4A, charging is not performed during the first predetermined period (0.5 hour) in the first fixed period (1 hour), and the remaining During a predetermined period (0.5 hours), charging is performed with twice the power (20 kW) of the comparative example. Thus, charging of the first predetermined amount (10 kWh) is achieved in accordance with the end timing of the first fixed period (1 hour). In the charge control of the present embodiment, the charging start timing is delayed with respect to the start timing of the first fixed period in response to increasing the charging rate.

  Further, as shown in FIG. 5A, in the comparative example, when it is necessary to discharge the second predetermined amount (10 kWh) in the second fixed period (1 hour), during the second fixed period. Discharge is performed with uniform power (10 kW). This equal power corresponds to a value obtained by dividing the second predetermined amount (10 kWh) by the time length (1 hour) of the second fixed period.

  On the other hand, in the discharge control according to the present embodiment, as shown in FIG. 4A, the second fixed period (1 hour), from the start of the second fixed period, for a predetermined period (0.5 hours). Discharge is performed at twice the power (20 kW) of the comparative example, and no discharge is performed for the remaining predetermined period (0.5 hours). Thus, a predetermined amount (10 kWh) of discharge is achieved earlier than the timing at which the second fixed period (1 hour) ends. In the discharge control according to the present embodiment, the discharge is completed earlier than the elapse of the second fixed period in response to the discharge being performed at an increased discharge rate.

  When it is assumed that the storage battery 22 changes SOC by 50% by charging or discharging with an electric energy of 10 kWh, the transition of the SOC corresponding to the charge / discharge profile shown in FIG. 4A is as shown in FIG. Thus, the SOC transition corresponding to the charge / discharge profile shown in FIG. 5A is as shown in FIG. In the graphs shown in FIGS. 4B and 5B, the horizontal axis is time, and the vertical axis is SOC.

  FIG. 6 is a graph for explaining the cycle deterioration characteristics. 6A shows an example of the cycle deterioration characteristics when the charge / discharge profile shown in FIG. 4A is executed, and FIG. 6B shows the charge / discharge profile shown in FIG. 5A. An example of the cycle deterioration characteristic is shown. In FIG. 6, the horizontal axis represents time, and the vertical axis represents the degree of deterioration progress per unit time. The degree of deterioration per unit time is a value normalized by an appropriate standard.

  The degree of deterioration (cycle deterioration) per unit time of the storage battery 22 accompanying charging / discharging is generally proportional to the charge / discharge rate. For this reason, in the charge / discharge control of the present embodiment, the degree of deterioration per unit time during charge / discharge is twice that of the charge / discharge control of the comparative example, as shown in FIG. However, the charge / discharge time is half that of the comparative example. For this reason, the degree of progress of cycle deterioration (cycle deterioration amount) when charging and discharging a predetermined amount of power is the same as in the case of charge / discharge control of the present embodiment (the area of the hatched portion in FIG. 6A corresponds). The charge / discharge control of the comparative example is the same as in the case of the charge / discharge control (the area of the hatched portion in FIG. 6B corresponds).

  FIG. 7 is a graph for explaining aged deterioration (storage deterioration) characteristics. FIG. 7A shows an example of the aging deterioration characteristic when the charge / discharge profile shown in FIG. 4A is executed, and FIG. 7B shows the charge / discharge profile shown in FIG. 5A. An example of the aging deterioration characteristic is shown. In FIG. 7, the horizontal axis represents time, and the vertical axis represents the degree of deterioration progress per unit time. The degree of deterioration per unit time is a value normalized by an appropriate standard.

  At the time of charging / discharging, in addition to the above-described cycle deterioration, aging deterioration also proceeds. The progress of aging deterioration depends on the SOC, and the degree of deterioration (aging deterioration) per unit time of the storage battery 22 generally increases as the SOC increases. In FIG. 7A and FIG. 7B, the progress of aging deterioration (aging deterioration amount) when charging and discharging a predetermined amount of power corresponds to the area of the hatched portion.

  The area of the hatched portion in FIG. 7A is 0.65 (= 2h × 0.2 + 1h × 0.5 / 2). On the other hand, the area of the hatched portion in FIG. 7B is 0.9 (= 2h × 0.2 + 2h × 0.5 / 2). That is, the degree of progress of aging deterioration when charging / discharging a predetermined amount of electric power is smaller in the case of charge / discharge control of this embodiment than in the case of charge / discharge control of the comparative example (approximately 28% reduction). )

  The deterioration progress after charging / discharging of the storage battery 22 is a combination of the progress of cycle deterioration and the progress of aging deterioration. As described above, when the charge / discharge control of this embodiment is performed and the charge / discharge control of the comparative example (conventional) is compared, the progress of cycle deterioration is the same, but the progress of aging deterioration is the same. Is reduced in the present embodiment. That is, according to the charge / discharge control of this embodiment, the life of the storage battery 22 can be extended.

  A method for determining the charge / discharge conditions in the charge / discharge control of this embodiment will be described. First, the charging condition determination method will be described. In the case where it is necessary to charge the first predetermined amount (c1) in the first fixed period (time length t1), the charging rate is increased and the charging start timing is set higher than the start timing of the first fixed period. The slower it is, the more the deterioration over time during charging can be reduced (see FIG. 7). That is, it is preferable that the charging rate at the time of charging is made as fast as possible (enlarged) while satisfying the above-described formula (1) only from the criterion of reducing aging deterioration.

  FIG. 8 is a graph for explaining the upper limit of the charge / discharge rate, where the horizontal axis indicates the power during charge / discharge, and the vertical axis indicates the degree of progress of cycle deterioration caused by charge / discharge. In FIG. 8, it means that a charge / discharge rate becomes large, so that the electric power at the time of charging / discharging becomes large. In general, as shown in FIG. 8, the progress of cycle deterioration increases as the charge / discharge rate increases, and when the charge / discharge rate increases considerably, the progress of cycle deterioration is accelerated. For this reason, if the charge / discharge rate is increased too much, the effect of reducing the degree of progress of aging described above is offset by the effect of acceleration of the degree of progress of cycle deterioration, and the life of the storage battery 22 can be extended. There is a risk of disappearing.

  Therefore, when determining the charging conditions, it is preferable to take care not to increase the charging rate in consideration of the acceleration of the progress of cycle deterioration. In detail, the total deterioration progress that combines the progress of cycle deterioration and the progress of aging of the storage battery 22 takes a first predetermined amount (c1) over a first fixed period (time length t1). ) At a uniform speed (= c1 / t1), the charging rate is preferably determined so as to be smaller than that (comparison condition A).

  The end timing of charging is preferably as close as possible to the end timing of the first fixed period in order to maximize the effect of reducing aging degradation. In the present embodiment, the end timing of charging is substantially the same as the end timing of the first certain period. Then, while satisfying the above-described formula (1), the charge rate is determined so that the charge rate is lower than the charge rate at which the total deterioration progress is the same as in the case of the comparison condition A. At this time, it is preferable that the charging rate is determined so that the total deterioration progress is as small as possible as compared with the comparison condition A. In determining the charging rate, for example, experiments, simulations, etc. regarding the relationship between the charging rate and the progress of cycle deterioration per unit time, and the relationship between the SOC and the progress of aging deterioration per unit time, etc. Need to know in advance.

  Moreover, since the charge rate of the storage battery 22 cannot exceed the upper limit value of the charge rate determined by the rating of the PCS 21, it is necessary to set the charge rate in consideration of this upper limit value. When the charging rate determined from the total deterioration progress is equal to or lower than the upper limit value determined by the rating of the PCS 21, this charging rate may be adopted. On the other hand, when the charging rate determined from the total progress of deterioration exceeds the upper limit determined by the rating of the PCS 21, the upper limit may be adopted as the charging rate. As described above, by determining the charging rate, the time for delaying the charging start timing with respect to the start timing of the first fixed period is determined.

  The charging conditions determined as described above may be stored in advance in the memory 23a and read by the controller 23 as necessary. Alternatively, a configuration in which the charge rate is appropriately calculated by the controller 23 based on predetermined conditions stored in the memory 23a may be used. The predetermined conditions include, for example, a relationship (table or relational expression) between the charge rate and the degree of progress of cycle deterioration per unit time, and a relation between the SOC and the degree of progress of aging deterioration per unit time (table or relation). Formula) and the like.

  Next, a method for determining discharge conditions will be described. When it is necessary to discharge the second predetermined amount (c2) in the second fixed period (time length t2), the discharge rate is increased so that the discharge end timing is set higher than the end timing of the second fixed period. The earlier, the more aged deterioration during discharge can be reduced (see FIG. 7). That is, it is preferable that the discharge rate at the time of discharge is made as fast as possible (enlarged) while satisfying the above-described equation (2) only from the criterion of reducing aging deterioration.

  As in the case of the above-described charging, it is preferable to take care not to increase the discharge rate in consideration of the fact that the progress of cycle deterioration is accelerated (see FIG. 8) when determining the discharge conditions. . In detail, the total deterioration progress, which is the sum of the progress of cycle deterioration and the progress of aging of the storage battery 22, takes a second predetermined amount (c2) over a second fixed period (time length t2). ) At a uniform rate (= c2 / t2), the discharge rate is preferably determined so as to be smaller than that (Comparison condition B).

  The discharge start timing is preferably as close as possible to the start timing of the second fixed period in order to maximize the effect of reducing aging deterioration. In this embodiment, the discharge start timing is substantially the same as the start timing of the second fixed period. Then, the discharge rate is determined so that the discharge rate is smaller than the discharge rate at which the total deterioration progress is the same as in the case of the comparison condition B while satisfying the above-described formula (2). At this time, it is preferable that the discharge rate is determined so that the total deterioration progress is as small as possible as compared with the comparison condition B. In determining the discharge rate, for example, experiments, simulations, etc. regarding the relationship between the discharge rate and the progress of cycle deterioration per unit time, and the relationship between the SOC and the progress of aging deterioration per unit time, etc. Need to know in advance.

  In addition, since the discharge rate of the storage battery 22 cannot exceed the upper limit value of the discharge rate determined by the rating of the PCS 21, it is necessary to set the discharge rate in consideration of this upper limit value. When the discharge rate determined from the total degree of deterioration is equal to or lower than the upper limit value determined by the rating of the PCS 21, this discharge rate may be adopted. On the other hand, when the discharge rate determined from the total degree of deterioration exceeds the upper limit determined by the rating of the PCS 21, the upper limit may be adopted as the discharge rate. As described above, by determining the discharge rate, the time at which the discharge end timing is advanced with respect to the end timing of the second fixed period is determined.

  The discharge conditions determined as described above may be stored in the memory 23a in advance and read by the controller 23 as necessary. Alternatively, a configuration in which the discharge rate is appropriately calculated by the controller 23 based on a predetermined condition stored in the memory 23a may be used. The predetermined conditions include, for example, the relationship between the discharge rate and the progress of cycle deterioration per unit time (table or relational expression), and the relationship between the SOC and the progress of aging deterioration per unit time (table or relationship). Formula) and the like.

  The embodiment described above is an exemplification of the present invention, and the power storage device and the power supply system of the present invention are not limited to the configuration described above. That is, the configuration of the embodiment described above can be changed as appropriate without departing from the spirit of the present invention.

  For example, in the above, the example in which the charge rate to the storage battery 22 and the discharge rate from the storage battery 22 are the same is shown, but the charge rate and the discharge rate may be different. Further, the charge rate and the discharge rate may be changed to different values in the middle.

  Moreover, in the above, the example in which the charge amount to the storage battery 22 and the discharge amount from the storage battery 22 are the same is shown, but the life extension control of the present invention is also applied when the charge amount and the discharge amount are different. Is possible.

  Further, in the above, an example is shown in which discharge is started immediately after the storage battery 22 is charged. However, the life of the present invention is also extended to a configuration in which discharge is started after a while after charging. Control is applicable. Further, depending on the case, a configuration in which the life extension control of the present invention is applied only in the case of charging or only in the case of discharging may be applied, and the present invention includes such a form.

  In addition, the power storage device and the power supply system of the present invention are not limited to stationary devices, and can be applied to moving bodies such as vehicles, ships, airplanes, robots, and power-assisted bicycles.

DESCRIPTION OF SYMBOLS 1 Power supply system 10 Electric power supply part 20 Power storage device 21 PCS (power conversion part)
22 Storage battery 23 Controller (control part)

Claims (10)

A storage battery,
A control unit that performs control related to charging of the storage battery;
A power storage device comprising:
The control unit causes the storage battery to be charged at a first speed that satisfies the following formula (1) when the storage battery needs to be charged for a first predetermined amount in a first fixed period, and A power storage device that delays a start timing of charging from a start timing of the first predetermined period.
v1> c1 / t1 (1)
v1: First speed c1: First predetermined amount t1: Time length of a first fixed period   The power storage device according to claim 1, wherein the control unit makes the end timing of the charging substantially the same as the end timing of the first predetermined period.   The controller is configured to charge the first predetermined amount at a uniform rate (= c1 / t1) over the first predetermined period when the deterioration degree of the storage battery increases or decreases according to the charging speed. The power storage device according to claim 1, wherein the first speed is set to be smaller than the first speed. In addition to control related to charging of the storage battery, the control unit is provided to perform control related to discharge of the storage battery,
The controller, when it is necessary to perform a second predetermined amount of discharge from the storage battery in a second fixed period, causes the discharge at a second rate that satisfies the following formula (2), and The power storage device according to any one of claims 1 to 3, wherein an end timing of discharge is advanced from an end timing of the second predetermined period.
v2> c2 / t2 (2)
v2: Second speed c2: Second predetermined amount t2: Time length of the second fixed period   The power storage device according to claim 4, wherein the control unit makes the discharge start timing substantially the same as the start timing of the second predetermined period.   The controller is configured to discharge the second predetermined amount at a uniform rate (= c2 / t2) over the second fixed period when the deterioration degree of the storage battery increases or decreases according to the discharge rate. The power storage device according to claim 4 or 5, wherein the second speed is set to be smaller. Comprising a power converter electrically connected to the storage battery;
The power storage according to any one of claims 1 to 6, wherein the control unit sets the first speed and the second speed to be equal to or lower than an upper limit value of a charge / discharge speed determined by a rating of the power conversion unit. apparatus. A storage battery,
A control unit that performs control related to discharging of the storage battery;
A power storage device comprising:
The controller, when it is necessary to perform a second predetermined amount of discharge from the storage battery in a second fixed period, causes the discharge at a second rate that satisfies the following formula (2), and A power storage device that advances discharge end timing earlier than end timing of the second predetermined period.
v2> c2 / t2 (2)
v2: Second speed c2: Second predetermined amount t2: Time length of the second fixed period   The power storage device according to claim 8, wherein the control unit makes the start timing of the discharge substantially the same as the start timing of the second fixed period. A power supply unit capable of supplying power to an external load;
The power storage device according to any one of claims 1 to 9, which is provided so as to be able to charge power from the power supply unit and is capable of discharging to an external load.
A power system.

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