JP2020024935A - Power storage system and computer program - Google Patents

Abstract

To provide a power storage system capable of improving estimation accuracy of a state of a power storage element.SOLUTION: In a power storage system 10, a power storage element state estimation device 100 for estimating a state of a power storage element 200 comprises: a determination unit 110 that determines whether or not a first amount of change representing an amount of change of capacity of the power storage element 200 in a first period from a first point of time to a second point of time is smaller than a predetermined amount, where the first point of time is a first point of time at which either one of charging and discharging to/from the power storage element 200 has been switched to the other, and the second time point is a point of time, next to the first point of time, at which the other has been switched to the one; and a state estimation unit 140 that when it is determined that the first amount of change is smaller than a predetermined amount, estimates a state of the power storage element 200 by making a first deterioration amount representing a deterioration amount caused by electrification of the power storage element 200 in the first period be reduced to a value smaller than a value of the first deterioration amount obtained by using a rule to be applied when it is determined that the first amount of change is equal to or larger than a predetermined amount.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power storage system for estimating a state of a power storage element and a computer program.

  Power storage elements such as lithium ion secondary batteries have been used as power supplies for mobile devices such as notebook computers and mobile phones, but in recent years have been used in a wide range of fields such as power supplies for electric vehicles. Conventionally, a technique has been proposed for estimating the state of such a storage element based on information such as charge / discharge history (for example, see Patent Documents 1 and 2). In this technology, the life of a power storage element is predicted using information such as a charge / discharge history.

JP 2013-89424 A JP 2014-81238 A

  However, in the above-described conventional technology, there is a problem that when the charge / discharge history becomes complicated, the accuracy of estimating the state of the power storage element may be reduced.

  That is, for example, when the storage element is operated in a substation or the like, a minute and complicatedly changing current is often superimposed, and the charge / discharge history becomes complicated. The present inventors have assiduously studied and, when the charge / discharge history is thus complicated, if all the charge / discharge histories are calculated by the same formula, the state of the power storage element cannot be accurately estimated, and the estimation accuracy Was found to decrease.

  SUMMARY An advantage of some aspects of the invention is to provide a power storage system and a computer program that can improve the accuracy of estimating the state of a power storage element.

  In order to achieve the above object, a power storage system according to one embodiment of the present invention is a power storage system including a power storage element and a power storage element state estimation device that estimates a state of the power storage element, wherein the power storage element state estimation is performed. The device has a first point in time when switching from one of charging and discharging to the storage element to the other, a second point in time after switching from the other to the one after the first point in time, and A first change amount indicating a change amount of the capacitance of the power storage element in a first period from one time point to the second time point, and a determining unit that determines whether the first change amount is smaller than a predetermined amount; When it is determined that the amount is smaller than the predetermined amount, the first deterioration amount indicating the amount of deterioration due to energization of the power storage element during the first period, the first change amount is determined to be equal to or more than the predetermined amount. Suitable for the case Is the is reduced to a value smaller than the value of the first deterioration amount obtained by using the rule, and a state estimation unit for state estimates of the storage element.

  According to this, the power storage element state estimating device included in the power storage system determines that the first change amount indicating the change amount of the capacity of the power storage element during the period in which the charge and discharge of the power storage element is switched is smaller than the predetermined amount. Next, the state of the storage element is estimated by reducing the first deterioration amount indicating the amount of deterioration due to energization of the storage element from a value obtained by normal estimation calculation. Here, the inventors of the present application have conducted intensive studies and as a result, when a power storage element is operated in a substation or the like, a current that changes minutely and in a complicated manner is often superimposed, and when the capacity changes minutely, It has been found that the influence on the amount of deterioration due to energization is small. For this reason, according to the power storage element state estimating device provided in the power storage system, the first deterioration amount when the capacity is minutely changed is reduced from a value obtained by a normal estimation calculation, so that the state of the power storage element state is reduced. The estimation accuracy can be improved.

  Further, the state estimating unit, when it is determined that the first change amount is smaller than the predetermined amount, reduces the first deterioration amount to zero, and estimates the state of the power storage element. Is also good.

  In addition, as a result of intensive studies, the inventors of the present application have found that the first deterioration amount when the capacitance is slightly changed can be ignored. Therefore, according to the power storage element state estimating device, when it is determined that the first change amount is smaller than the predetermined amount, the power storage element state is estimated by reducing the first deterioration amount to zero. It is possible to improve the estimation accuracy of the state of the element.

  Further, the state estimating unit may further include, in the one of the charging and the discharging, a deterioration amount due to energization of the power storage element in a second period having a change amount smaller than the first change amount. The second deterioration amount indicating is reduced to a value smaller than the value of the second deterioration amount obtained using a rule applied when the first change amount is determined to be equal to or more than the predetermined amount. The state of the power storage element may be estimated.

  According to this, the power storage element state estimating device reduces the second deterioration amount indicating the deterioration amount due to energization of the power storage element in the second period from a value obtained by normal estimation calculation, and changes the state of the power storage element. presume. Here, as a result of diligent studies, the inventors of the present application have found that, when the capacity is minutely changed, both charging and discharging have little effect on the amount of deterioration due to energization of the storage element. For this reason, according to the power storage element state estimation device, the accuracy of estimating the state of the power storage element can be improved by reducing the amount of deterioration in both charging and discharging.

  Further, the state estimating unit obtains the second period including a plurality of periods in which the total amount of change is equal to or less than the first amount of change, and deteriorates due to the energization of the power storage element in each of the plurality of periods. The second deterioration amount indicating the amount may be reduced.

  According to this, when the second period is divided into a plurality of periods, the power storage element state estimating device reduces the second deterioration amount indicating the deterioration amount due to energization of the power storage element in each of the plurality of periods. As described above, according to the power storage element state estimation device, even when the second period is divided into a plurality of periods, it is possible to improve the estimation accuracy of the state of the power storage device by reducing the amount of deterioration in the plurality of periods. .

  Further, the state estimating unit determines whether the second period is included in the predetermined third period, and only when it is determined that the second period is included in the third period, the second The deterioration amount may be reduced.

  According to this, the power storage element state estimating device reduces the second deterioration amount only when it is determined that the predetermined third period includes the second period. That is, according to the power storage element state estimation device, when the third period does not include the second period, the deterioration amount is not reduced, so that the deterioration amount can be prevented from being excessively reduced. The state estimation accuracy can be improved.

  In addition, the determination unit sets the time when the state is switched from the state in which charging and discharging to the power storage element is not performed to the other as the first time, or charges and discharges the power storage element from the other. The point in time when the state is switched to the state in which the operation is not performed may be set as the second point in time, and whether the first change amount is smaller than the predetermined amount may be determined.

  According to this, the power storage element state estimation device sets the time when the power storage element switches from the idle state in which charging and discharging are not performed to the charging / discharging state in which charging or discharging is performed as a first time, or The above-described determination is made with the point in time when the state is switched to the neglected state as the second point in time. As described above, according to the power storage element state estimating apparatus, even when the state changes from the idle state to the charge / discharge state, or even when the state changes from the charge / discharge state to the idle state, the deterioration amount is reduced, so that the power storage element The state estimation accuracy can be improved.

  Further, the present invention can also be realized as a power storage element state estimation method in which the characteristic processing performed by the power storage element state estimation device provided in the power storage system is performed as steps. Further, the present invention can also be realized as an integrated circuit including a characteristic processing unit included in the power storage element state estimation device. Further, the present invention can be realized as a program for causing a computer to execute characteristic processing included in the power storage element state estimation method, or a computer-readable CD-ROM (Compact Disc-Read Only Memory) in which the program is recorded. It can also be realized as a recording medium such as. Then, such a program can be distributed via a recording medium such as a CD-ROM and a transmission medium such as the Internet.

  ADVANTAGE OF THE INVENTION According to the electric storage system which concerns on this invention, the estimation precision of the state of an electric storage element can be improved.

1 is an external view of a power storage system including a power storage element state estimation device according to an embodiment of the present invention. 1 is a block diagram illustrating a functional configuration of a power storage element state estimation device according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of data written to charge / discharge history data according to the embodiment of the present invention. 5 is a flowchart illustrating an example of a process of estimating a state of a storage element by the storage element state estimation device according to the embodiment of the present invention. 9 is a flowchart illustrating an example of a process in which a switching determination unit and a change amount determination unit of a determination unit according to an embodiment of the present invention acquire a first change amount. It is a flowchart which shows an example of the process which the state estimation part which concerns on embodiment of this invention reduces a first deterioration amount. FIG. 4 is a diagram illustrating a process in which the storage element state estimation device according to the embodiment of the present invention estimates the state of the storage element. FIG. 4 is a diagram illustrating a process in which the storage element state estimation device according to the embodiment of the present invention estimates the state of the storage element. FIG. 4 is a diagram illustrating a process in which the storage element state estimation device according to the embodiment of the present invention estimates the state of the storage element. FIG. 4 is a diagram illustrating a process in which the storage element state estimation device according to the embodiment of the present invention estimates the state of the storage element. FIG. 4 is a diagram illustrating a process in which the storage element state estimation device according to the embodiment of the present invention estimates the state of the storage element. It is a figure showing the premise data used for explaining the effect of the electric storage element state estimation device concerning an embodiment of the invention. It is a figure showing the premise data used for explaining the effect of the electric storage element state estimation device concerning an embodiment of the invention. It is a figure showing an effect of an electric storage element state estimating device concerning an embodiment of the invention. It is a figure showing an effect of an electric storage element state estimating device concerning an embodiment of the invention. It is a figure showing an effect of an electric storage element state estimating device concerning an embodiment of the invention. It is a conceptual diagram for explaining the effect of the storage element state estimation device according to the embodiment of the present invention. 1 is a block diagram showing a configuration for realizing a storage element state estimation device according to an embodiment of the present invention with an integrated circuit.

  Hereinafter, a power storage element state estimation device according to an embodiment of the present invention and a power storage system including the power storage element state estimation device will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present invention. In addition, among the components in the following embodiments, components not described in the independent claims indicating the highest concept are described as arbitrary components.

(Embodiment)
First, the configuration of the power storage system 10 will be described.

  FIG. 1 is an external view of a power storage system 10 including a power storage element state estimation device 100 according to an embodiment of the present invention.

  As shown in the figure, the power storage system 10 includes a plurality (five in the figure) of power storage element state estimation devices 100, a plurality of (five in the figure) power storage elements 200, and the plurality of power storage element state estimations. The housing 100 includes the device 100 and a plurality of power storage elements 200. That is, one storage element state estimation device 100 is arranged corresponding to one storage element 200.

  The storage element state estimation device 100 is a flat circuit board provided with a circuit that is disposed above the storage element 200 and that estimates a state of the storage element 200 at a predetermined time. Specifically, one power storage element state estimation device 100 is connected to one power storage element 200, acquires information from the one power storage element 200, and acquires the information of the one power storage element 200 at a predetermined time. Estimate a state such as a deteriorated state.

  Here, power storage element state estimation devices 100 are disposed above respective power storage elements 200, but power storage element state estimation devices 100 may be disposed anywhere. The shape of power storage element state estimation device 100 is not particularly limited.

  Further, the number of power storage element state estimation devices 100 is not limited to five, and may be another number or one. That is, one power storage element state estimation device 100 may be arranged corresponding to a plurality of power storage elements 200, or a plurality of power storage element state estimation devices 100 may be arranged corresponding to one power storage element 200. May be. That is, any number of storage element state estimation devices 100 may be connected to any number of storage elements 200. The detailed functional configuration of the power storage element state estimation device 100 will be described later.

  The storage element 200 is a secondary battery that can charge and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. In FIG. 5, five rectangular storage elements 200 are arranged in series to form a battery pack. Note that the number of power storage elements 200 is not limited to five, and may be another number or one. In addition, the shape of the power storage element 200 is not particularly limited, and may be a columnar shape, an elongated columnar shape, or the like.

  The energy storage device 200 includes a container and electrode terminals (a positive electrode terminal and a negative electrode terminal) protruding from the container, and the inside of the container is connected to the electrode body and the electrode body and the electrode terminal. Current collectors (a positive electrode current collector and a negative electrode current collector) are provided, and a liquid such as an electrolytic solution is sealed. The electrode body is formed by winding a positive electrode, a negative electrode, and a separator. Note that the electrode body may be a stacked electrode body in which flat electrode plates are stacked instead of a wound electrode body.

The positive electrode is an electrode plate in which a positive electrode active material layer is formed on the surface of a positive electrode base material layer which is a long strip-shaped metal foil made of aluminum, an aluminum alloy, or the like. As the positive electrode active material used for the positive electrode active material layer, a known material can be appropriately used as long as it is a positive electrode active material capable of inserting and extracting lithium ions. For example, as the positive electrode active material, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , and LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, and the like), lithium titanate, A spinel-type lithium manganese oxide such as LiMn ₂ O ₄ or LiMn _1.5 Ni _0.5 O ₄ ; LiMO ₂ (M is one or more transition metals selected from Fe, Ni, Mn, Co, etc.) Element) or the like.

The negative electrode is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode substrate layer which is a long strip-shaped metal foil made of copper, a copper alloy, or the like. In addition, as a negative electrode active material used for the negative electrode active material layer, a known material can be appropriately used as long as it is a negative electrode active material capable of inserting and extracting lithium ions. For example, as a negative electrode active material, lithium metal, lithium alloy (lithium metal-containing alloy such as lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy) Other alloys capable of occluding and releasing lithium, carbon materials (eg, graphite, non-graphitizable carbon, easily graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), silicon oxide, metal oxide, lithium metal oxide (Eg, Li ₄ Ti ₅ O ₁₂ ), a polyphosphoric acid compound, or a compound of a transition metal and a Group 14 to Group 16 element such as Co ₃ O ₄ or Fe ₂ P, which is generally called a conversion anode. Can be

  The separator is a microporous sheet made of a resin. Note that the separator used for the storage element 200 is not particularly different from that conventionally used, and a known material can be appropriately used as long as the performance of the storage element 200 is not impaired. The type of electrolyte (non-aqueous electrolyte) enclosed in the container is not particularly limited as long as the performance of the storage element 200 is not impaired, and various types can be selected.

  The storage element 200 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery or a capacitor.

  Next, a detailed functional configuration of power storage element state estimation device 100 will be described.

  FIG. 2 is a block diagram showing a functional configuration of power storage element state estimation device 100 according to the embodiment of the present invention.

  The storage element state estimation device 100 is a device that estimates the state of the storage element 200. Here, the state of the storage element 200 refers to an electrical or mechanical state of the storage element 200, for example, a deterioration state indicating the degree of deterioration of the performance of the storage element 200, or an abnormal behavior of the storage element 200. An abnormal state indicating whether or not there is an error is included.

  As shown in the figure, the power storage element state estimation device 100 includes a determination unit 110, a state estimation unit 140, and a storage unit 150. The determining unit 110 includes a switching determining unit 120 and a change amount determining unit 130. Further, storage unit 150 is a memory for storing various data for estimating the state of power storage element 200, and stores charge / discharge history data 151 and deterioration information data 152.

  The determination unit 110 sets a time point at which one of charging and discharging of the power storage element 200 is switched to the other as a first time point, a time point at which the storage element 200 is switched from the other one to the next time after the first time point, and a second time point. It is determined whether or not the first change amount indicating the change amount of the capacity of power storage element 200 during the first period from the first time point to the second time point is smaller than a predetermined amount. In addition, determination unit 110 performs charging and discharging of power storage element 200 from the state in which charging and discharging of power storage element 200 are not performed and the other is set as the first time point or from the other side. It may be determined whether the first change amount is smaller than a predetermined amount, with the time point when the state is switched to the non-existent state as the second time point.

  Here, the processing performed by the switching determination unit 120 and the change amount determination unit 130 included in the determination unit 110 will be described, and the processing performed by the determination unit 110 will be specifically described.

  Switching determination unit 120 determines whether the direction of the current to power storage element 200 has been switched, thereby determining whether one of charging and discharging of power storage element 200 has been switched to the other. Specifically, switching determination unit 120 acquires an average value of the current for each predetermined unit period, and determines whether or not the direction of the current with respect to power storage element 200 has been switched using the average value. The processing performed by the switching determination unit 120 will be described in more detail below.

  First, switching determination section 120 acquires a charge / discharge history of power storage element 200 up to a time when the state of power storage element 200 is to be estimated (hereinafter, referred to as a predetermined time). Specifically, switching determination section 120 is connected to power storage element 200, and detects and acquires a charge / discharge history from power storage element 200. In other words, switching determination unit 120 is electrically connected to the electrode terminal of power storage element 200 on which power storage element state estimating device 100 is mounted by wiring such as a lead wire. Then, switching determination unit 120 acquires a charge / discharge history from power storage element 200 via the wiring during a period up to a predetermined time point.

  More specifically, switching determination section 120 constantly monitors the operation state of power storage element 200, and acquires a charge / discharge history each time a predetermined change is observed in the operation state of power storage element 200. For example, the switching determination unit 120 monitors a change in the voltage of the power storage element 200, and determines that the power storage element 200 has been charged / discharged when the voltage difference exceeds 0.1% of the current voltage. Obtain a discharge history. In this case, for example, the switching determination unit 120 acquires the charging / discharging history each time the change in the voltage of the storage element 200 exceeds 0.1%. That is, the switching determination unit 120 acquires the charging / discharging history at a sampling cycle in which the change in the voltage of the storage element 200 is 0.1%. Note that the timing of acquiring the charging / discharging history is not limited to the above, and the switching determination unit 120 may use any sampling cycle such as acquiring the charging / discharging history at a sampling cycle in which the usage period of the power storage element 200 is 1 second. May be used. When the sampling cycle is set to a fixed period, a cycle of 1 second or less is preferable.

  Here, the charging / discharging history is an operation history of the power storage element 200, information indicating a point in time when the power storage element 200 performs charging or discharging (hereinafter referred to as a charging / discharging point), and a power storage element at the charging / discharging point. The information includes information related to the charge or discharge performed by the power supply 200.

  Specifically, the information indicating the charge / discharge time point is information including a date (year, month, day), time, and the like, at which the power storage element 200 performed charging or discharging. The information on the charge or discharge performed by the storage element 200 is information indicating a voltage and a current at the time of charge or discharge performed by the storage element 200.

  In the present embodiment, the switching determination unit 120 calculates and acquires the average value of the voltage and the current for each predetermined unit period. Note that the unit period may be any period and may be determined as appropriate according to the user's settings. For example, the unit period is 1 second, 4 seconds, 30 seconds, 1 minute, or the like, but is preferably 4 seconds. Further, for example, the switching determination unit 120 sets the value of the current to be positive when the storage element 200 is being charged, and sets the value of the current when the storage element 200 is being discharged. Is negative, and the average value of the current is calculated.

Further, switching determination section 120 determines the SOC (State) of power storage element 200 for each unit period.
Of Charge). For example, the switching determination unit 120 calculates the SOC by estimating the SOC from the voltage value of the storage element 200 using the SOC-OCV characteristic indicating the relationship between the SOC and the OCV (Open Circuit Voltage). I do. Alternatively, switching determination section 120 may calculate the SOC from the current value of power storage element 200 using a current integration method that estimates the SOC by integrating the charge / discharge current.

  Then, the switching determination unit 120 stores the acquired information indicating the charge / discharge time, the voltage (average value), the current (average value), and the SOC in the storage unit 150 in association with each unit period. Write to the charge / discharge history data 151.

  Further, switching determination section 120 determines whether or not the direction of the current with respect to power storage element 200 has been switched using the value of the current. That is, the switching determination unit 120 reads the current (average value) from the charge / discharge history data 151 and, for example, when the value of the current changes from plus to minus or from minus to plus, the direction of the current with respect to the power storage element 200. Is determined to have been switched.

  Then, switching determination section 120 determines whether the direction of the current to power storage element 200 has been switched, and thereby determines whether one of charging and discharging of power storage element 200 has been switched to the other. In other words, the switching determination unit 120 determines that switching has been performed from charging to discharging when the current value has changed from positive to negative, and determines that switching has been performed from discharging to charging when the current value has changed from negative to positive. I do.

  Then, switching determination unit 120 detects a time point at which one of charging and discharging of power storage element 200 is switched to the other as a first time point, and a time point at which the switching from the other to the one is performed after the first time point. Is detected as the second time point.

  Further, switching determination section 120 also detects, as the first time point, the time point at which the power storage element 200 is switched from a state in which charging and discharging are not performed (hereinafter, referred to as an idle state) to the other. Alternatively, the switching determination unit 120 also detects, as the second time point, the time point at which the state has been switched to the idle state.

  That is, the switching determination unit 120 also detects the time when the current value changes from zero to plus or minus as the first time, and also determines the time when the current value changes from minus or plus to zero to the second time. Is detected. Note that a minute current always flows through the storage element 200. In this case, not only the current value is zero, but also when the current value is equal to or less than a certain value, the concept of the neglected state. Include in. Even if the current value is zero for a moment, it is included in the concept of the neglected state.

  The switching determination unit 120 then stores the charge / discharge state (charge, discharge, or idle) of the power storage element 200 for each unit period and the detected switching time (first time, second time) in the charging / discharging history data 151. Write more to.

  FIG. 3 is a diagram showing an example of data written in the charge / discharge history data 151 according to the embodiment of the present invention.

  As shown in the figure, data indicating the charge / discharge history, which is the operation history of the storage element 200 up to a predetermined time, is written in the charge / discharge history data 151. In other words, the charge / discharge history data 151 corresponds to “charge / discharge time”, “voltage (average value)”, “current (average value)”, “SOC”, “charge / discharge state”, and “switching time”. The attached data table is written.

  Here, in the “charge / discharge time”, a date (year, month, day), time, and the like, which are information indicating the time when the power storage element 200 has charged or discharged, are stored. That is, the switching determination unit 120 measures the time from a timer or the like, acquires the date (year, month, day), time, and the like, and writes the date and time into the “charge / discharge time”. Note that any unit such as year, month, day, hour, minute, second, or number of cycles (number of charge / discharge) may be used as a unit at the time of charge / discharge.

  In addition, “voltage (average value)”, “current (average value)”, and “SOC” include, as information relating to charge or discharge performed by the power storage element 200, a unit period at the time of charge or discharge performed by the power storage element 200. Is stored, information indicating the average value of the voltage, the average value of the current, and the SOC. In the “state of charge / discharge”, any one of information of “charge”, “discharge”, and “left” is stored. In the “switching time”, the switching time (first time, second time) detected by the switching determination unit 120 is stored.

  Returning to FIG. 2, the processing performed by the change amount determination unit 130 will be described in detail.

  The change amount determination unit 130 determines whether the first change amount indicating the change amount of the capacity of the power storage element 200 in the first period from the first time point to the second time point detected by the switching determination unit 120 is smaller than a predetermined amount. Judge.

  Specifically, change amount determining section 130 sets the amount of change in the SOC of power storage element 200 in the first period as the first amount of change, and determines whether the amount of change in the SOC is smaller than a predetermined amount. In other words, the change amount determination unit 130 reads the SOC values at the first time point and the second time point from the charge / discharge history data 151 and calculates the difference between the two SOC values, so that the power storage element during the first period is obtained. A change amount of the SOC of 200 is calculated and set as a first change amount. Then, the change amount determining unit 130 determines whether the first change amount is smaller than the predetermined amount. The predetermined amount is a small value, for example, about 0.5% or 0.36%.

  Next, a process performed by the state estimating unit 140 will be described.

  When it is determined that the first change amount is smaller than the predetermined amount, the state estimating unit 140 determines the first deterioration amount indicating the deterioration amount due to energization of the power storage element 200 in the first period, and sets the first change amount to the predetermined amount. The value is reduced to a value smaller than the value of the first deterioration amount obtained using the rule applied when it is determined that the above is the case. Here, the “first deterioration amount indicating the amount of deterioration due to energization of the storage element 200” is a decrease in performance caused by energization of the storage element 200, and is, for example, a capacity of the storage element 200, a capacity maintenance rate. , SOC, voltage, etc., and a capacity reduction rate.

  Further, “the value of the first deterioration amount obtained by using the rule applied when the first change amount is determined to be equal to or more than the predetermined amount” means that the change amount determination unit 130 determines the first change amount. This is a value of the deterioration amount calculated according to a mathematical formula or the like used when it is determined that the amount is equal to or more than the fixed amount. For example, when the change amount determination unit 130 determines that the first change amount is equal to or more than a predetermined amount, and the state estimation unit 140 has a rule that calculates the deterioration amount using a predetermined relational expression, This is the value of the deterioration amount calculated using the relational expression. Note that the state estimating unit 140 may calculate the deterioration amount using a conventionally known general relational expression as the relational expression, or the state estimating unit 140 may use a new relational expression. May be derived to calculate the deterioration amount.

  That is, when the change amount determining unit 130 determines that the amount of change in the SOC is equal to or more than the predetermined amount, the state estimating unit 140 calculates the deterioration amount using a predetermined relational expression or the like. Determines that the amount of change in SOC is smaller than the predetermined amount, the deterioration amount is reduced from a value calculated using a predetermined relational expression or the like.

  Specifically, when it is determined that the first change amount is smaller than the predetermined amount, state estimating section 140 reduces the first deterioration amount to zero. Note that the state estimating unit 140 does not reduce the first deterioration amount to zero, but reduces the first deterioration amount to a value slightly larger than zero, or subtracts a certain amount from the deterioration amount calculated using the predetermined relational expression. Alternatively, the deterioration amount may be reduced to about 50% to 10%.

  In addition, the state estimating unit 140 further includes, in one of the charging state and the discharging state, a deterioration amount due to energization of the storage element 200 in a second period having a change amount equal to or smaller than the first change amount. The deterioration amount is reduced to a value smaller than the value of the second deterioration amount obtained using a rule applied when the first change amount is determined to be equal to or more than the predetermined amount. In other words, if the first period was a charged period, the second period was a discharged period, and if the first period was a discharged period, the second period was charged. Period. Further, the second period is preferably a period immediately before or immediately after the first period, but may be a period slightly away from the first period. Further, the second period may be a period having a change amount equal to or smaller than the first change amount, but is preferably a period having the same change amount as the first change amount.

  Further, the second period need not be a single continuous period, and may be a period including a plurality of discontinuous periods. In this case, the state estimating unit 140 acquires a second period including a plurality of periods in which the total amount of change is equal to or less than the first amount of change, and determines the amount of deterioration due to the energization of the power storage element 200 in each of the plurality of periods. Is reduced. Note that the second period preferably includes a plurality of periods in which the total amount of change is the same as the first amount of change.

  Further, the state estimating unit 140 determines whether or not the predetermined third period includes the second period, and reduces the second deterioration amount only when determining that the third period includes the second period. Let it. That is, since it is preferable that the second period is not too far from the first period, the state estimation unit 140 limits the second period in which the second deterioration amount can be reduced to the case where the second period is included in the third period. Thus, the second deterioration amount is reduced. In other words, if the amount of deterioration is reduced even when minute capacitance changes (SOC fluctuations) are repeated in a long period exceeding the third period, the amount of deterioration is reduced to the one that originally caused a large capacitance change. There is a possibility that it will be done. However, such a possibility can be excluded by determining the period in which the deterioration amount is reduced as described above.

  The state estimating unit 140 writes the deterioration amount calculated as described above to the deterioration information data 152 stored in the storage unit 150. Then, state estimation section 140 reads the deterioration amount up to a predetermined time from deterioration information data 152 and estimates the state of power storage element 200 at the predetermined time. Specifically, state estimation section 140 estimates a deterioration state indicating the degree of deterioration in performance of power storage element 200, an abnormal state indicating whether power storage element 200 is exhibiting abnormal behavior, and the like. For example, the state estimating unit 140 estimates a state of deterioration of the capacity such as what percentage the reversible capacity of the storage element 200 has decreased. Then, state estimation section 140 writes the result of estimating the state of power storage element 200 in deterioration information data 152.

  Next, the process in which power storage element state estimation device 100 estimates the state of power storage element 200 will be described in detail. FIG. 4 is a flowchart illustrating an example of a process of estimating the state of power storage element 200 by power storage element state estimation device 100 according to the embodiment of the present invention. FIG. 5 is a flowchart illustrating an example of a process in which the switching determination unit 120 and the change amount determination unit 130 of the determination unit 110 according to the embodiment of the present invention acquire a first change amount. FIG. 6 is a flowchart illustrating an example of a process in which the state estimating unit 140 according to the embodiment of the present invention reduces the first deterioration amount. FIGS. 7 to 11 are diagrams illustrating a process of estimating the state of power storage element 200 by power storage element state estimation device 100 according to the embodiment of the present invention.

  First, as illustrated in FIG. 4, the determination unit 110 acquires a first change amount indicating a change amount of the capacitance of the power storage element 200 in the first period (S102: change amount acquisition step).

  Specifically, the determination unit 110 sets the time when one of the charging and discharging of the power storage element 200 is switched to the other as the first time, and the time when the switching from the other to the one is performed after the first time. The first change amount indicating the change amount of the capacitance of the power storage element 200 in the first period from the first time point to the second time point is obtained. Alternatively, the determination unit 110 performs charging and discharging of the storage element 200 from the state in which charging and discharging are not performed on the storage element 200 as the first time, or from the other. The point in time when the state is switched to the non-existing state is set as a second point in time, and it is determined whether the first change amount is smaller than a predetermined amount.

  More specifically, the switching determination unit 120 determines whether one of charging and discharging of the storage element 200 has been switched to the other, and whether the switching has been switched from the other to the one. The first time point and the second time point are detected. Alternatively, the first time point or the second time point is detected by determining whether or not the switching determination unit 120 has switched from the idle state to the storage element 200 to the other state, or from the other state to the idle state. I do.

  That is, as illustrated in FIG. 7, for example, the switching determination unit 120 detects a time point at which the storage element 200 switches from discharging to charging as a first time point, and detects a time point at which switching from charging to discharging occurs as a second time point. Alternatively, for example, as illustrated in FIG. 8, the switching determination unit 120 detects a time point at which the storage device 200 switches from the idle state to the charging as the first time point, and detects a time point at which the power storage element 200 switches to the discharging state as the second time point. . Alternatively, for example, as illustrated in FIG. 9, the switching determination unit 120 detects a point in time when the storage element 200 switches from discharging to charging as a first point in time, and determines a point in time when switching from charging to the idle state (state in which the current is zero). Is detected as the second time point.

  Then, change amount determining section 130 acquires a first change amount indicating the amount of change in the capacity of power storage element 200 during the first period from the first time point to the second time point detected by switching determination section 120. That is, for example, as illustrated in FIG. 7, the change amount determination unit 130 acquires the first change amount indicating the change amount Q1 of the capacitance of the power storage element 200 in the first period from the first time point to the second time point. Note that further details of the process in which the determination unit 110 (the switching determination unit 120 and the change amount determination unit 130) acquires the first change amount will be described later.

  Then, the determining unit 110 determines whether the obtained first change amount is smaller than a predetermined amount (S104: determination step). Specifically, the change amount determining unit 130 determines whether the first change amount is smaller than a predetermined amount. That is, change amount determining section 130 sets the amount of change in SOC of power storage element 200 in the first period as the first amount of change, and determines whether the amount of change in SOC is smaller than the predetermined amount.

  That is, as shown in FIG. 7, for example, the change amount determination unit 130 calculates the change amount Q1 of the capacitance of the power storage element 200 by integrating the current in the first period (that is, multiplying the current by the time). Then, change amount determining section 130 calculates the SOC change amount of power storage element 200 corresponding to the change amount Q1 and sets the calculated change amount as the first change amount, and determines whether the SOC change amount is smaller than a predetermined amount. I do. In the present embodiment, the predetermined amount is, for example, 0.5% or 0.36%, but the numerical value is not particularly limited, and may be a fixed value and may be changed according to the situation. .

  When the determining unit 110 determines that the first change amount is smaller than the predetermined amount (YES in S104), the state estimating unit 140 reduces the first deterioration amount (S106: deterioration amount reduction step). Specifically, state estimating section 140 is applied to the first deterioration amount indicating the deterioration amount due to energization of power storage element 200 in the first period when the first change amount is determined to be equal to or more than a predetermined amount. It is reduced to a value smaller than the value of the first deterioration amount obtained using the rule.

  That is, as shown in FIG. 7, for example, when the determining unit 110 determines that the SOC change amount corresponding to the change amount Q1 is smaller than the predetermined amount, the state estimating unit 140 determines that the SOC corresponding to the change amount Q1 Reduce the amount of degradation. The details of the process by which the state estimating unit 140 reduces the first deterioration amount will be described later.

  Then, state estimation section 140 estimates the state of power storage element 200 (S108: state estimation step). When determining section 110 determines that the first change amount is equal to or more than the predetermined amount (NO in S104), state estimating section 140 determines the state of power storage element 200 without reducing the first deterioration amount. Is estimated. For example, as illustrated in FIG. 7, when the determination unit 110 determines that the change amount of the SOC corresponding to the change amount Q2 is equal to or more than the predetermined amount, the state estimating unit 140 may determine that the first deterioration corresponding to the change amount Q2 The amount is calculated using a predetermined relational expression or the like without being reduced.

  That is, when the determination unit 110 determines that the first change amount is equal to or more than the predetermined amount, the state estimation unit 140 calculates the deterioration amount using a predetermined relational expression or the like. If it is determined that the one change amount is smaller than the predetermined amount, the deterioration amount is reduced from a value calculated using a predetermined relational expression or the like. Thus, state estimation section 140 estimates the state of power storage element 200 by reducing the first deterioration amount according to the situation.

  Thus, the process of estimating state of power storage element 200 by power storage element state estimation device 100 ends. The power storage element state estimation device 100 can also estimate the future state of the power storage element 200 (e.g., remaining life) by predicting the charge / discharge history of the power storage element 200 in the future.

  Next, the details of the process (S102 in FIG. 4) in which the switching determination unit 120 and the change amount determination unit 130 of the determination unit 110 obtain the first change amount will be described.

  As shown in FIG. 5, first, the switching determination unit 120 acquires an average value of the current for each predetermined unit period (S202). Then, switching determination unit 120 determines whether the state of charge / discharge for power storage element 200 has been switched using the obtained average value (S204). That is, switching determination section 120 determines whether the direction of the current to power storage element 200 has been switched, and thereby determines whether one of charging and discharging of power storage element 200 has been switched to the other. Alternatively, the switching determination unit 120 determines whether the value of the current has changed from zero to plus or minus, or whether the value has changed from minus or plus to zero, and thereby determines whether the state of the idle state or the charge / discharge state is satisfied. It is determined whether or not one has been switched to the other.

  When switching determination section 120 determines that the state of charge / discharge for power storage element 200 has not been switched (NO in S204), processing for acquiring the average value of the current for each unit period (S202) is repeated. .

  Then, when switching determination section 120 determines that the state of charge / discharge for power storage element 200 has been switched (YES in S204), it obtains a first time point and a second time point (S206). Specifically, the switching determination unit 120 detects, as a first time point, a time point at which one of the charging and discharging of the power storage element 200 is switched to the other, and, after the first time point, switches from the other to the one. The time point at which the switching was performed is detected as the second time point. Further, switching determination section 120 also detects, as the first time point, the time point at which the storage element 200 is switched from the idle state in which charging and discharging are not performed to the other. Alternatively, the switching determination unit 120 also detects, as the second time point, the time point at which the state has been switched to the idle state.

  Then, the change amount determining unit 130 calculates the SOC change amount as the first change amount (S208). That is, the change amount determination unit 130 determines the SOC change amount as the first change amount indicating the change amount of the capacity of the power storage element 200 in the first period from the first time point to the second time point detected by the switching determination unit 120. calculate.

  As described above, the process (S102 in FIG. 4) in which the switching determination unit 120 and the change amount determination unit 130 of the determination unit 110 acquire the first change amount ends.

  Next, the details of the process (S106 in FIG. 4) by which the state estimation unit 140 reduces the first deterioration amount will be described.

  As shown in FIG. 6, first, the state estimating unit 140 reduces the first deterioration amount in the first period (S302). That is, the state estimating unit 140 sets the first deterioration amount to a value smaller than the value of the first deterioration amount obtained using the rule applied when the first change amount is determined to be equal to or more than the predetermined amount. Reduce. Specifically, for example, as illustrated in FIG. 7, the state estimating unit 140 reduces the first deterioration amount corresponding to the change amount Q1 of the capacitance of the storage element 200 to zero.

  Then, the state estimating unit 140 determines whether the second period having the amount of change equal to or smaller than the first amount of change is included in the predetermined third period in one of the charging and discharging states. (S304). Specifically, for example, as shown in FIG. 7, the state estimating unit 140 determines whether or not the second period corresponding to the variation Q3 having a magnitude equal to or less than the variation Q1 is included in the third period. . The third period may be determined as appropriate according to the setting of the user, and is, for example, 1 minute, 10 minutes, 1 hour, or the like, and is preferably a period of 30 minutes to 1 hour.

  Here, since the first period is a period during which the battery is charged, the second period is a period during which the battery is discharged. Further, the second period is preferably a period immediately before or immediately after the first period, but may be a period slightly away from the first period as shown in FIG. Further, the second period may be a period having a change amount equal to or smaller than the first change amount, but is preferably a period having the same change amount as the first change amount. That is, the change amount Q3 is preferably equal to the change amount Q1. However, in the case as shown in FIG. 9, it is preferable that the change amount Q3 is the same as the sum of the change amounts Q4 and Q5.

  When the state estimating unit 140 determines that the third period includes the second period (YES in S304), the state estimating unit 140 reduces the second deterioration amount in the second period (S306). That is, the state estimating unit 140 calculates the second deterioration amount in the second period having a change amount equal to or less than the first change amount in one of the charging and discharging states, Is reduced to a value smaller than the value of the second deterioration amount obtained using the rule applied when it is determined that

  For example, in FIG. 7, the state estimating unit 140 determines that the second period corresponding to the change amount Q3 having a size equal to or smaller than the change amount Q1 is included in the third period. Then, the state estimating unit 140 reduces the second deterioration amount in the second period corresponding to the change amount Q2 in the discharge state to zero.

  Here, when the second period is not a single continuous period but a plurality of discontinuous periods, the state estimating unit 140 determines that the total change amount is equal to or smaller than the first change amount. A second period including a period is acquired, and the second deterioration amount indicating the deterioration amount due to the conduction of the power storage element 200 in each of the plurality of periods is reduced.

  That is, as shown in FIG. 10, for example, the state estimating unit 140 acquires a second period including a plurality of periods corresponding to the variation amounts Q6 and Q7 in which the total variation amount is equal to or less than the variation amount Q1, and The second deterioration amount in each of the plurality of periods is reduced to zero. The second period includes a plurality of periods in which the total amount of change is the same as the first amount of change (in FIG. 10, the sum of the amounts of change Q6 and Q7 is the same as the amount of change Q1). preferable.

  When the state estimation unit 140 determines that the third period does not include the second period (NO in S304), the process ends without reducing the second deterioration amount in the second period. . That is, as shown in FIG. 11, for example, when the state estimating unit 140 determines that the second period corresponding to the change amount Q7 is not included in the third period, the second deterioration corresponding to the change amount Q7 is performed. The process ends without reducing the amount.

  Thus, the process of reducing the first deterioration amount by the state estimation unit 140 (S106 in FIG. 4) ends.

  Next, with reference to FIG. 12A to FIG. 14, an effect of the power storage element state estimation device 100 will be described.

  FIG. 12A and FIG. 12B are diagrams showing premise data used to explain the effect of power storage element state estimation device 100 according to the embodiment of the present invention. Specifically, FIG. 12A is a diagram illustrating a current pattern of a target battery, and FIG. 12B is a diagram illustrating a distribution of a change amount of the SOC calculated based on the current pattern. 13A to 13C are diagrams showing the effects of the power storage element state estimation device 100 according to the embodiment of the present invention. Specifically, FIG. 13A is a graph showing measured values and a comparative example, FIG. 13B is a graph showing measured values and an example, and FIG. 13C is a graph showing measured values of a comparative example and an example. It is the table which compared the difference from. FIG. 14 is a conceptual diagram for describing the effect of power storage element state estimation device 100 according to the embodiment of the present invention.

  Here, the current pattern shown in FIG. 12A is a current pattern based on the JC08 mode (four-second average), which is a traveling mode for calculating the fuel efficiency of an automobile. This current pattern was applied to the electric storage element of the present application, and a test simulating actual use was performed. FIG. 12B shows the timing at which the sign of the current value switches in the current pattern shown in FIG. 12A, calculates the amount of change in SOC (ΔSOC), and arranges the SOC from the one with the smallest value of the amount of change in SOC. Things. From this result, the maximum amount of change in SOC due to charging was 0.36%, which was an extremely small value of less than 0.5%. Note that the amount of change in SOC is calculated by dividing the amount of change in capacitance of the storage element by the reversible capacity.

  Next, the results of conducting a test simulating actual use in the above current patterns are shown in FIGS. 13A to 13C. In other words, FIG. 13A shows an estimation result (Comparative Example 1) in the case of using the conventional power storage element state estimating device that does not perform state estimation by power storage element state estimating device 100 in the above-described embodiment, and actually measures the power storage element State value (measured value 1). Specifically, this figure shows changes in the capacity of the storage element at 55, 109, 159, and 209 days after the start of the test. Note that Comparative Example 1 and Measured Value 1 are an estimation result and a measurement result under an environment 20 ° C. higher than room temperature.

  FIG. 13B shows an estimation result (Example 1) in the case where the amount of deterioration in energization where the amount of change of the SOC is less than 0.5% is set to zero by the electric storage element state estimation device 100 in the above embodiment, and the electric storage element. 5 shows the actually measured state value (measurement value 1). Specifically, this figure shows changes in the capacity of the storage element at 55, 109, 159, and 209 days after the start of the test. Note that the first embodiment is an estimation result in an environment in which the storage element state estimating device 100 is used and is higher than room temperature by 20 ° C., and corresponds to the comparative example 1 and the measurement value 1 described above.

  FIG. 13C shows the test results of Comparative Example 1 shown in FIG. 13A and Example 1 shown in FIG. 13B. Specifically, FIG. 6 shows an error between Comparative Example 1 and Measurement Value 1, and an error between Example 1 and Measurement Value 1. The error is calculated by dividing the difference between the capacities by the initial capacity. As shown in these figures, Example 1 has a smaller error from the measured value 1 than Comparative Example 1.

  As described above, since the deterioration of the battery hardly progresses due to the small change in the SOC, the estimation accuracy is improved by ignoring the deterioration due to the small change in the SOC. For example, as shown in FIG. 14A, it is assumed that when the battery is discharged, charging corresponding to SOC 20% and discharging corresponding to SOC 120% (charge / discharge corresponding to SOC 140% in total) are performed. If the charge 20% and the discharge 20% are caused by a small change in SOC, the charge 20% and the discharge 20% can be ignored. For this reason, as shown in FIG. 14B, it is possible to perform the estimation assuming that the charging corresponding to the SOC of 0% and the discharging corresponding to the SOC of 100% have been performed ignoring the charge of 20% and the discharge of 20%. it can. Thereby, estimation accuracy can be improved.

The specifications of the batteries targeted in the above test are as follows in all Examples and Comparative Examples. That is, as for the specifications of the battery, as the positive electrode mixture (positive electrode active material layer), spinel-type lithium manganese oxide was used as the positive electrode active material, acetylene black was used as the conductive additive, and polyvinylidene fluoride was used as the binder. In the negative electrode mixture (negative electrode active material layer), non-graphitizable carbon was used as the negative electrode active material, and polyvinylidene fluoride was used as the binder. In addition, EC (ethylene carbonate), EMC (ethyl methyl carbonate), and DMC (dimethyl carbonate) were mixed in the electrolyte at a ratio of 25:55:20, and 1 mol / L of LiPF ₆ was added to the mixed solution. . In estimating the battery capacity, for example, a model equation of deterioration during the use period t when the deterioration coefficient is a can be calculated as f (t) = a√t. It should be noted that the above-mentioned model equation of deterioration is only an example, and if it complies with the gist of the present application, it belongs to the technical scope of the present invention.

  As described above, according to power storage element state estimating device 100 included in power storage system 10 according to the embodiment of the present invention, the amount of change in capacity of power storage element 200 during the period in which charging and discharging of power storage element 200 are switched is described. When it is determined that the one change amount is smaller than the predetermined amount, the first deterioration amount indicating the deterioration amount due to energization of the power storage element 200 is reduced from a value obtained by normal estimation calculation, and the power storage element 200 Estimate the state. Here, as a result of intensive studies, the inventors of the present application have found that when the power storage element 200 is operated in a substation or the like and a minute and complicatedly changing current is often superimposed, and the capacity is slightly changed, the power storage element It has been found that there is little effect on the amount of deterioration due to 200 current supply. That is, for example, in the case of a lithium ion battery, deterioration due to energization of the storage element 200 is mainly caused by repeated expansion and contraction of the active material due to insertion / desorption of lithium ions into / from the active material. It is assumed that the mechanical contact between the active material particles becomes insufficient due to the repeated destruction of the electrodes or the repeated expansion and contraction of the electrode plate due to charge and discharge. However, when the amount of supplied electricity is very small, that is, when the SOC fluctuation is very small, the degree of expansion and contraction accompanying this is very small. It is assumed that deterioration does not occur without performing the above. Therefore, according to the power storage element state estimation device 100 included in the power storage system 10, the first deterioration amount when the capacity is slightly changed is reduced from a value obtained by a normal estimation calculation, so that the power storage element 200. Can be improved in the estimation accuracy of the state.

  In addition, as a result of intensive studies, the inventors of the present application have found that the first deterioration amount when the capacitance is slightly changed can be ignored. For this reason, according to the storage element state estimation device 100, when it is determined that the first change amount is smaller than the predetermined amount, the state of the storage element 200 is estimated by reducing the first deterioration amount to zero. In addition, the accuracy of estimating the state of the storage element 200 can be improved.

  Further, power storage element state estimation device 100 reduces the state of power storage element 200 by reducing the second deterioration amount indicating the deterioration amount due to energization of power storage element 200 in the second period from a value obtained by normal estimation calculation. presume. Here, as a result of intensive studies, the inventors of the present application have found that, when the capacity is slightly changed, both the charge and the discharge have little effect on the amount of deterioration due to energization of the storage element 200. For this reason, according to power storage element state estimation device 100, the accuracy of estimating the state of power storage element 200 can be improved by reducing the amount of deterioration in both charging and discharging.

  In addition, when the second period is divided into a plurality of periods, the power storage element state estimation device 100 reduces the second deterioration amount indicating the deterioration amount due to energization of the power storage element 200 in each of the plurality of periods. As described above, according to power storage element state estimation device 100, even when the second period is divided into a plurality of periods, the amount of deterioration in the plurality of periods is reduced, thereby improving the estimation accuracy of the state of power storage device 200. Can be.

  The storage element state estimation device 100 reduces the second deterioration amount only when it is determined that the predetermined third period includes the second period. That is, according to the storage element state estimation device 100, when the third period does not include the second period, the deterioration amount is not reduced, so that the deterioration amount can be prevented from being excessively reduced. The accuracy of estimating the state of the state 200 can be improved.

  In addition, power storage element state estimation device 100 can easily determine whether one of charging and discharging has switched to the other by determining whether the direction of the current has switched.

  In addition, power storage element state estimation device 100 can eliminate a case in which the current direction is frequently switched by determining whether or not the current direction has been switched based on the average value of the current in each unit period.

  In addition, power storage element state estimation device 100 sets the amount of change in SOC of power storage element 200 in the first period as the first amount of change, and determines whether the amount of change in SOC is smaller than a predetermined amount. In other words, according to power storage element state estimation device 100, it is possible to accurately determine whether to reduce the deterioration amount by using the change amount of the SOC as the first change amount.

  In addition, the power storage element state estimation device 100 sets the time when the power storage element 200 switches from the idle state in which charging and discharging are not performed to the charging and discharging state in which charging or discharging is performed as a first time, or The above-described determination is made with the point in time when the state is switched to the idle state as the second point in time. As described above, according to the storage element state estimation device 100, even when the state changes from the idle state to the charge / discharge state, or when the state changes from the charge / discharge state to the idle state, the amount of deterioration is reduced. The accuracy of estimating the state of the state 200 can be improved.

  As described above, the power storage element state estimation device 100 and the power storage system 10 according to the embodiment of the present invention have been described, but the present invention is not limited to this embodiment. In other words, the embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, in the above-described embodiment, change amount determining section 130 determines whether or not the change amount of the SOC of power storage element 200 during the first period is smaller than a predetermined amount. However, the change amount determination unit 130 may make a determination using a change amount of the capacitance of the power storage element 200 or a change amount of DOD (Depth Of Discharge) instead of the change amount of the SOC. That is, the change amount determination unit 130 determines that the change amount of the capacitance or the DOD of the power storage element 200 in the first period is the first change amount, and determines whether the change amount of the capacitance or the DOD is smaller than a predetermined amount. It may be.

  In the above-described embodiment, the state estimation unit 140 reduces the second deterioration amount only when determining that the third period includes the second period. However, the state estimating unit 140 may reduce all the second deterioration amounts without setting the third period.

  Further, in the above embodiment, the state estimation unit 140 reduces the second deterioration amount when reducing the first deterioration amount. However, the state estimating unit 140 may reduce only the first deterioration amount and not reduce the second deterioration amount.

  Further, in the above embodiment, the switching determination unit 120 obtains the average value of the current for each unit period, and determines whether or not the direction of the current with respect to the storage element 200 has been switched using the average value. did. However, the switching determination unit 120 may determine whether or not the current direction has been switched from the acquired current value without using the average value of the current.

  Further, in the above embodiment, switching determination unit 120 determines whether the direction of current to power storage element 200 has been switched, thereby determining whether one of charging and discharging of power storage element 200 has been switched to the other. It was decided to judge. However, the switching determination unit 120 may determine whether one of charging and discharging has been switched to the other based on other information, such as information from the outside, instead of the direction of the current.

  Further, in the above-described embodiment, the determination unit 110 determines that the time point when the state is switched from the idle state to the charge / discharge state is the first time point, or that the time point when the state is switched from the charge / discharge state to the idle state is the second time point. It was determined whether the amount was smaller than a predetermined amount. However, the determination unit 110 may not perform the determination when switching from the idle state to the charging / discharging state or switching from the charging / discharging state to the idle state.

  Further, in the above embodiment, power storage element state estimation device 100 includes storage unit 150, and stores information for charge / discharge history and state estimation of power storage element 200 in storage unit 150. However, power storage element state estimation device 100 does not include storage unit 150, and may use an external memory instead of storage unit 150.

  In addition, power storage element state estimation device 100 has a function of referring to data on the estimated state of power storage element 200, detecting an abnormality of power storage element 200, and estimating a safe state that issues a safety alarm. It may be.

  The processing unit included in the storage element state estimation device 100 according to the present invention is typically realized as an LSI (Large Scale Integration) which is an integrated circuit. That is, for example, as illustrated in FIG. 15, the present invention is realized as an integrated circuit 101 including the determination unit 110 and the state estimation unit 140. FIG. 15 is a block diagram illustrating a configuration in which power storage element state estimation device 100 according to the embodiment of the present invention is implemented by an integrated circuit.

  Each processing unit included in the integrated circuit 101 may be individually formed into one chip, or may be formed into one chip so as to include a part or all of the processing units. Although an LSI is used here, it may be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. After the LSI is manufactured, a field programmable gate array (FPGA) that can be programmed or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used. Furthermore, if an integrated circuit technology that replaces the LSI appears due to the progress of the semiconductor technology or another technology derived therefrom, the functional blocks may be naturally integrated using the technology. Adaptation of biotechnology is possible.

  Further, the present invention can be realized not only as such a storage element state estimation device 100 but also as a storage element state estimation method in which the characteristic processing performed by the storage element state estimation device 100 is performed as a step. Can be.

  Further, the present invention can be realized as a program for causing a computer (processor) to execute characteristic processing included in the power storage element state estimation method, or a computer (processor) readable non-temporary recording in which the program is recorded. Medium, for example, flexible disk, hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray (registered trademark) Disc), semiconductor memory, flash memory, magnetic storage device, optical disk, paper tape It can also be realized as any medium. Then, such a program can be distributed via a recording medium such as a CD-ROM and a transmission medium such as the Internet.

  Further, a mode constructed by arbitrarily combining the components included in the above-described embodiments is also included in the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a power storage system or the like that can improve the estimation accuracy of the state of a power storage element.

REFERENCE SIGNS LIST 10 power storage system 100 power storage element state estimating device 101 integrated circuit 110 determination unit 120 switching determination unit 130 change amount determination unit 140 state estimation unit 150 storage unit 151 charge / discharge history data 152 deterioration information data 200 power storage element 300 housing case

Claims (2)

A power storage system including a power storage element and a power storage element state estimation device that estimates a state of the power storage element,
The storage element state estimation device,
The first time is the time at which one of the charging and discharging of the power storage element is switched to the other, and the second time is the time at which the other is switched to the one after the first time, from the first time. A determining unit that determines whether the first change amount indicating the change amount of the capacity of the power storage element in the first period up to the second time point is smaller than a predetermined amount,
When it is determined that the first change amount is smaller than the predetermined amount, the first change amount indicating the deterioration amount due to energization of the power storage element in the first period is equal to or more than the predetermined amount. And a state estimating unit for estimating the state of the power storage element by reducing the value to a value smaller than the value of the first deterioration amount obtained using a rule applied when it is determined that . A computer gram for causing a computer to estimate a state of a storage element,
On the computer,
The first time is the time at which one of the charging and discharging of the power storage element is switched to the other, and the second time is the time at which the other is switched to the one after the first time, from the first time. A determination process of determining whether or not a first change amount indicating a change amount of the capacitance of the power storage element in a first period until the second time point is smaller than a predetermined amount;
When it is determined that the first change amount is smaller than the predetermined amount, the first change amount indicating the deterioration amount due to energization of the power storage element in the first period is equal to or more than the predetermined amount. A state estimation process of estimating the state of the power storage element by reducing the value to a value smaller than the value of the first deterioration amount obtained using a rule applied when it is determined that .

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