JP6607079B2 - Storage element state estimation device and storage element state estimation method - Google Patents

Description

  The present invention relates to a storage element state estimation device and a storage element state estimation method for estimating a state of a storage element.

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

JP2013-89424A JP 2014-81238 A

  However, the above conventional technique has a problem that when the charge / discharge history becomes complicated, the estimation accuracy of the state of the power storage element may be lowered.

  That is, for example, when a power storage element is operated in a substation or the like, a minute and complicated current is often superimposed and the charge / discharge history becomes complicated. The inventors of the present application, as a result of intensive studies, when the charge / discharge history becomes complicated in this way, if all charge / discharge histories are calculated with the same formula, the state of the storage element cannot be accurately estimated, and the estimation accuracy Has been found to decrease.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a storage element state estimation device and a storage element state estimation method capable of improving the estimation accuracy of the state of a storage element.

  In order to achieve the above object, a power storage element state estimation device according to one aspect of the present invention is a power storage element state estimation device that estimates a state of a power storage element, from either charging or discharging of the power storage element. The time point when switching to the other is the first time point, the time point when switching from the other to the one after the first time point is the second time point, and the power storage in the first period from the first time point to the second time point A determination unit configured to determine whether or not a first change amount indicating a change amount of the capacitance of the element is smaller than a predetermined amount; and when the first change amount is determined to be smaller than the predetermined amount, The first deterioration obtained by using a rule applied when it is determined that the first change amount is equal to or greater than the predetermined amount, the first deterioration amount indicating a deterioration amount due to energization of the power storage element in one period. Less than the quantity value It is reduced to, and a state estimation unit for estimating the state of the electric storage device.

  According to this, the storage element state estimation device determines that the first change amount indicating the change amount of the capacity of the storage element during the period when the charge / discharge of the storage element is switched is smaller than the predetermined amount. The first deterioration amount indicating the deterioration amount due to the energization is reduced from a value obtained by normal estimation calculation, and the state of the power storage element is estimated. Here, as a result of intensive studies, the inventors of the present invention have operated a power storage element at a substation, etc., and when a small and complicated change current is often superimposed and the capacity changes slightly, It was found that there was little effect on the amount of deterioration due to energization. Therefore, according to the storage element state estimation device, the first deterioration amount when the capacity changes slightly is reduced from the value obtained by the normal estimation calculation, thereby improving the estimation accuracy of the state of the storage element. Can be made.

  In addition, the state estimation unit estimates the state of the power storage element by reducing the first deterioration amount to zero when it is determined that the first change amount is smaller than the predetermined amount. Also good.

  Further, as a result of intensive studies, the inventors of the present application have found that the first deterioration amount when the capacity changes slightly can be ignored. Therefore, according to the power storage element state estimation device, when it is determined that the first change amount is smaller than the predetermined amount, the first deterioration amount is reduced to zero and the state of the power storage element is estimated, thereby The accuracy of estimating the state of the element can be improved.

  In addition, the state estimation unit further includes a deterioration amount due to energization of the power storage element in a second period having a change amount equal to or less than the first change amount in the one state of the charge and the discharge. And reducing the second deterioration amount 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 greater than the predetermined amount. The state of the power storage element may be estimated.

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

  Further, the state estimation unit acquires the second period including a plurality of periods in which the total change amount is equal to or less than the first change amount, and deterioration due to 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 estimation device reduces a second deterioration amount indicating a deterioration amount due to energization of the power storage element in each of the plurality of periods. Thus, according to the 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 storage element by reducing the amount of deterioration in the plurality of periods. .

  Further, the state estimation unit determines whether or not the second period is included in a predetermined third period, and only when the second period is determined to be included in the third period, the second period is included in the second period. The amount of deterioration may be reduced.

  According to this, the storage element state estimation device reduces the second deterioration amount only when it is determined that the second period is included in the predetermined third period. That is, according to the storage element state estimation device, when the second period is not included in the third 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 may charge and discharge the power storage element from the state when the power storage element is not charged and discharged as the first time point or from the other time point. It may be determined whether or not the first change amount is smaller than the predetermined amount, with the time point when the state is changed to the non-going state as the second time point.

  According to this, the storage element state estimation device sets the time point when the storage element is switched from the left state where charging and discharging are not performed to the charging / discharging state where charging or discharging is performed, or charging / discharging. The above determination is made with the time point when the state is switched to the neglected state as the second time point. Thus, according to the storage element state estimation device, the amount of deterioration of the storage element can be reduced by reducing the deterioration amount even when the state is changed from the left state to the charge / discharge state or when the state is changed from the charge / discharge state to the left state. The state estimation accuracy can be improved.

  The present invention can be realized not only as such a storage element state estimation device, but also as a storage system including a storage element and a storage element state estimation device that estimates the state of the storage element. Can do.

  In addition, the present invention can also be realized as a storage element state estimation method including a characteristic process performed by the storage element state estimation apparatus as a step. 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. The present invention is also realized as a program for causing a computer to execute characteristic processing included in the storage element state estimation method, or a computer-readable CD-ROM (Compact Disc-Read Only Memory) on which the program is recorded. It can also be realized as a recording medium. Such a program can be distributed via a recording medium such as a CD-ROM and a transmission medium such as the Internet.

  According to the storage element state estimation device according to the present invention, it is possible to improve the estimation accuracy of the state of the storage element.

It is an external view of an electrical storage system provided with the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the data written in the charging / discharging log | history data concerning embodiment of this invention. It is a flowchart which shows an example of the process in which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a flowchart which shows an example of the process in which the switching judgment part and change amount judgment part of the judgment part which concern on embodiment of this invention acquire a 1st change amount. It is a flowchart which shows an example of the process in which the state estimation part which concerns on embodiment of this invention reduces a 1st degradation amount. It is a figure explaining the process which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a figure explaining the process which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a figure explaining the process which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a figure explaining the process which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a figure explaining the process which the electrical storage element state estimation apparatus which concerns on embodiment of this invention estimates the state of an electrical storage element. It is a figure which shows the premise data used in order to demonstrate the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the premise data used in order to demonstrate the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a conceptual diagram for demonstrating the effect of the electrical storage element state estimation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure which implement | achieves the electrical storage element state estimation apparatus which concerns on embodiment of this invention with an integrated circuit.

  Hereinafter, a power storage device state estimation device according to an embodiment of the present invention and a power storage system including the power storage device state estimation device will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

(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 storage element state estimation devices 100, a plurality (five in the figure) of storage elements 200, and the plurality of storage element state estimations. The apparatus 100 and the storage case 300 which stores the some electrical storage element 200 are provided. That is, one power storage element state estimation device 100 is arranged corresponding to one power storage element 200.

  The storage element state estimation device 100 is a flat circuit board on which a circuit that is disposed above the storage element 200 and that estimates the state of the storage element 200 at a predetermined time is mounted. 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 stores the one power storage element 200 at a predetermined time. Estimate a state such as a deteriorated state.

  Here, power storage element state estimation device 100 is disposed above each power storage device 200, but power storage device state estimation device 100 may be disposed anywhere. Further, the shape of the 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, but may be other plural numbers or one. That is, one power storage element state estimation device 100 may be disposed corresponding to a plurality of power storage elements 200, or a plurality of power storage element state estimation devices 100 are disposed corresponding to one power storage element 200. It may be. That is, any number of power storage element states 200 may be connected to any number of power storage elements 200. The detailed functional configuration of the storage element state estimation device 100 will be described later.

  The power 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. Moreover, in the same figure, the five rectangular electrical storage elements 200 are arrange | positioned in series, and the assembled battery is comprised. Note that the number of power storage elements 200 is not limited to five, and may be other plural numbers or one. In addition, the shape of the electricity storage element 200 is not particularly limited, and may be a cylindrical shape or a long cylindrical shape.

  The power storage element 200 includes a container and electrode terminals (a positive terminal and a negative terminal) protruding from the container, and the electrode body, the electrode body, and the electrode terminal are connected to the inside of the container. Current collectors (a positive electrode current collector and a negative electrode current collector) are disposed, and a liquid such as an electrolytic solution is enclosed. The electrode body is formed by winding a positive electrode, a negative electrode, and a separator. The electrode body may be a laminated electrode body in which flat electrode plates are laminated 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 that is a long strip-shaped metal foil made of aluminum, an aluminum alloy, or the like. In addition, as a positive electrode active material used for a positive electrode active material layer, if it is a positive electrode active material which can occlude / release lithium ion, a well-known material can be used suitably. For example, as a positive electrode active material, a polyanion compound such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, Spinel type lithium manganese oxide such as LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ , LiMO ₂ (M is one or more transition metals selected from Fe, Ni, Mn, Co, etc.) Lithium transition metal oxides such as (element) can be used.

The negative electrode is an electrode plate in which a negative electrode active material layer is formed on the surface of a negative electrode base material layer that 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 a negative electrode active material layer, if it is a negative electrode active material which can occlude-release lithium ion, a well-known material can be used suitably. For example, as a negative electrode active material, lithium metal, lithium alloy (lithium metal-containing alloys such as lithium-silicon, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy) Other alloys that can occlude and release lithium, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), silicon oxide, metal oxide, lithium metal oxide (Li ₄ Ti ₅ O ₁₂ etc.), polyphosphoric acid compounds, compounds of transition metals and group 14 to group 16 elements such as Co ₃ O ₄ and Fe ₂ P, generally called conversion anodes, etc. It is done.

  The separator is a microporous sheet made of resin. Note that the separator used for the power storage element 200 is not particularly different from that conventionally used, and any known material can be used as long as it does not impair the performance of the power storage element 200. Moreover, as long as the electrolyte solution (nonaqueous electrolyte) enclosed in a container does not impair the performance of the electrical storage element 200, there is no particular limitation on the type thereof, and various types can be selected.

  In addition, the electrical storage element 200 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it.

  Next, a detailed functional configuration of the 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 apparatus 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 power storage element 200 refers to an electrical or mechanical state of the power storage element 200, for example, a deterioration state indicating a degree of deterioration of the performance of the power storage element 200, or an abnormal behavior of the power storage element 200. An abnormal condition indicating whether or not

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

  The determination unit 110 sets a time point when one of charging and discharging of the power storage element 200 is switched from one to the other as a first time point, and a time point when switching from the other time to the one after the first time point is set as a second time point. It is determined whether or not the first change amount indicating the change amount of the capacity of the power storage element 200 in the first period from one time point to the second time point is smaller than a predetermined amount. Further, the determination unit 110 sets the time point when the power storage element 200 is not charged and discharged to the other time as the first time point, or charges and discharges the power storage element 200 from the other time point. It may be determined whether or not the first change amount is smaller than a predetermined amount, with the time point when the state is switched to the state not changed as the second time point.

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

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

  First, the switching determination unit 120 acquires a charge / discharge history of the power storage element 200 up to a time point at which the state of the power storage element 200 is to be estimated (hereinafter referred to as a predetermined time point). Specifically, switching determination unit 120 is connected to power storage element 200 and detects and acquires a charge / discharge history from power storage element 200. That is, the switching determination unit 120 is electrically connected to the electrode terminal of the power storage element 200 on which the power storage element state estimation device 100 is placed by wiring such as a lead wire. Then, the switching determination unit 120 acquires a charge / discharge history from the power storage element 200 through the wiring in a period up to a predetermined time point.

  More specifically, the switching determination unit 120 constantly monitors the operating state of the power storage element 200 and acquires a charge / discharge history each time a predetermined change is observed in the operating state of the power storage element 200. For example, the switching determination unit 120 monitors the change in the voltage of the power storage element 200, and when the voltage difference exceeds 0.1% of the current voltage, the switching determination unit 120 considers that the power storage element 200 has been charged / discharged. Get the discharge history. In this case, for example, the switching determination unit 120 acquires the charge / discharge history every time the voltage change of the power storage element 200 exceeds 0.1%. That is, the switching determination unit 120 acquires the charge / discharge history at a sampling period in which the voltage change of the power 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 acquires any sampling cycle such as acquiring the charging / discharging history with a sampling period of 1 second for the storage element 200. May be used. When the sampling period is set to a certain period, a period of 1 second or less is preferable.

  Here, the charge / discharge history is an operation history of the power storage element 200, information indicating the time when the power storage element 200 is charged or discharged (hereinafter referred to as charge / discharge time), and the power storage element at the time of charge / discharge. This is information including information on charging or discharging performed by 200.

  Specifically, the information indicating the charging / discharging time point is information including a date (year / month / day) and time when the power storage element 200 is charged or discharged. Further, the information related to charging or discharging performed by the storage element 200 is information indicating voltage and current at the time of charging or discharging performed by the storage element 200.

  In the present embodiment, the switching determination unit 120 calculates and acquires an average value of voltage and current for each predetermined unit period. The unit period may be any period and may be determined as appropriate according to user settings. For example, the unit period is 1 second, 4 seconds, 30 seconds, 1 minute, etc., but 4 seconds is preferable. In addition, for example, when the storage element 200 is charged, the switching determination unit 120 sets the current value to be positive, and when the storage element 200 is discharged, the switch determination unit 120 sets the current value. The average value of current is calculated by subtracting.

  In addition, the switching determination unit 120 calculates and acquires the SOC (State Of Charge) of the power storage element 200 for each unit period. For example, the switching determination unit 120 calculates the SOC by estimating the SOC from the voltage value of the power storage element 200 using the SOC-OCV characteristic indicating the relationship between the SOC and the OCV (Open Circuit Voltage). To do. Alternatively, switching determination unit 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.

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

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

  Then, switching determination unit 120 determines whether or not the direction of current with respect to power storage element 200 has been switched, thereby determining whether or not one of charging and discharging of power storage element 200 has been switched to the other. That is, the switching determination unit 120 determines that the charging has been switched to discharging when the current value has changed from positive to negative, and has determined that the switching has been performed from discharging to charging when the current value has changed from negative to positive. To do.

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

  In addition, the switching determination unit 120 also detects the time point when the state is switched from the state where the power storage element 200 is not charged and discharged (hereinafter referred to as the neglected state) to the other, as the first time point. Alternatively, the switching determination unit 120 also detects the time point when the other is switched to the neglected state as the second time point.

  That is, the switching determination unit 120 detects the first time point even when the current value changes from zero to plus or minus, and also determines the second time point when the current value changes from minus or plus to zero. Is detected. Note that a minute current may always flow through the power storage element 200. In this case, not only the value of the current is zero but also the case where the current becomes a certain value or less, Include in Further, even if the period during which the current value is zero is momentary, it is included in the concept of the neglected state.

  Then, the switching determination unit 120 determines the charging / discharging state (charging, discharging, or leaving) of the power storage element 200 for each unit period and the detected switching time (first time, second time) as the charge / discharge 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, the charge / discharge history data 151 is written with data indicating a charge / discharge history, which is an operation history of the power storage device 200 up to a predetermined time. That is, the charge / discharge history data 151 corresponds to “charge / discharge time point”, “voltage (average value)”, “current (average value)”, “SOC”, “charge / discharge state”, and “switching time point”. The attached data table is written.

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

  In addition, “voltage (average value)”, “current (average value)”, and “SOC” include unit periods at the time of charging or discharging performed by the storage element 200 as information on charging or discharging performed by the storage element 200. Information indicating an average value of voltage, an average value of current, and SOC is stored. Further, in the “charge / discharge state”, information of “charge”, “discharge”, or “left” is stored. Further, the “switching time point” stores the switching time points (first time point and second time point) detected by the switching determination unit 120.

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

  The change amount determination unit 130 determines whether or not the first change amount indicating the change amount of the capacity of the 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. Determine whether.

  Specifically, change amount determination unit 130 uses the change amount of SOC of power storage element 200 in the first period as the first change amount, and determines whether or not the change amount of SOC is smaller than a predetermined amount. That is, the change amount determination unit 130 reads the SOC value 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, thereby storing the storage element in the first period. A change amount of the SOC of 200 is calculated and set as the first change amount. Then, the change amount determination unit 130 determines whether or not the first change amount is smaller than a predetermined amount. The predetermined amount is a small value of about 0.5% or 0.36%, for example.

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

  When the state estimation unit 140 determines that the first change amount is smaller than the predetermined amount, the state estimation unit 140 sets the first deterioration amount indicating the deterioration amount due to energization of the power storage element 200 in the first period, and the first change amount is 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 as above. Here, the “first deterioration amount indicating the amount of deterioration due to energization of the electricity storage element 200” is a decrease in performance caused by the electricity supply of the electricity storage element 200. For example, the capacity and capacity maintenance rate of the electricity storage element 200 , SOC, voltage and other deterioration amounts (decrease amounts), capacity reduction rate, and the like.

  Further, “the value of the first deterioration amount obtained using the rule applied when it is determined that the first change amount is equal to or greater than the predetermined amount” means that the change amount determination unit 130 indicates that the first change amount is It 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 not less than a fixed amount. For example, when the change amount determination unit 130 determines that the first change amount is equal to or greater than a predetermined amount, the state estimation unit 140 has a rule that calculates the deterioration amount using a predetermined relational expression. It is the value of the deterioration amount calculated using the relational expression. Note that the state estimation unit 140 may calculate the deterioration amount using a conventionally known general relational expression as the relational expression, or the state estimation part 140 may calculate a new relational expression. May be derived to calculate the amount of deterioration.

  That is, when the change amount determination unit 130 determines that the change amount of the SOC is equal to or greater than the predetermined amount, the state estimation unit 140 calculates the deterioration amount using a predetermined relational expression or the like, and the change amount determination unit 130. When it is determined that the change amount of the 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, the state estimation unit 140 reduces the first deterioration amount to zero when it is determined that the first change amount is smaller than a predetermined amount. The state estimation unit 140 does not reduce the first deterioration amount to zero, but reduces it to a value slightly larger than zero, or subtracts a certain amount from the deterioration amount calculated using the predetermined relational expression. Or may be reduced to about 50% to 10% of the deterioration amount.

  In addition, the state estimation unit 140 further indicates a second deterioration amount due to energization of the power storage element 200 in the second period having a change amount equal to or smaller than the first change amount in one state of charging and discharging. The amount of deterioration is reduced to a value smaller than the value of the second amount of deterioration obtained using the rule applied when the first change amount is determined to be equal to or greater than the predetermined amount. That is, in the case where the first period is charged, the second period is a discharged period, and in the case where the first period is discharged, the second period is charged. It is a period. 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. In addition, the second period may be a period having a change amount that is equal to or less than the first change amount, but is preferably a period having a change amount that is the same as the first change amount.

  The second period may not be one continuous period, but may be a period composed of a plurality of discontinuous periods. In this case, the state estimation unit 140 acquires a second period including a plurality of periods in which the total change amount is equal to or less than the first change amount, and the deterioration amount due to energization of the power storage element 200 in each of the plurality of periods. The second deterioration amount showing is reduced. The second period is preferably composed of a plurality of periods in which the total change amount is the same as the first change amount.

  The state estimation unit 140 determines whether or not the second period is included in the predetermined third period, and reduces the second deterioration amount only when it is determined that the second period is included in the third period. Let 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 that can reduce the second deterioration amount to a 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 a minute change in capacity (SOC fluctuation) is repeated over a long period exceeding the third period, the amount of deterioration is reduced to what originally caused a large change in capacity. There is a possibility of letting you. However, such a possibility can be eliminated by determining the period during which the deterioration amount is reduced as described above.

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

  Next, a process in which the storage element state estimation device 100 estimates the state of the storage element 200 will be described in detail. FIG. 4 is a flowchart illustrating an example of processing in which the storage element state estimation device 100 according to the embodiment of the present invention estimates the state of the storage element 200. FIG. 5 is a flowchart illustrating an example of processing 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 the first change amount. FIG. 6 is a flowchart illustrating an example of processing in which the state estimation unit 140 according to the embodiment of the present invention reduces the first deterioration amount. 7-11 is a figure explaining the process which the electrical storage element state estimation apparatus 100 which concerns on embodiment of this invention estimates the state of the electrical storage element 200. FIG.

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

  Specifically, the determination unit 110 sets a time point when one of charging and discharging of the power storage element 200 is switched to the other as the first time point, and a time point when switching from the other time to the one after the first time point is the first time point. The first change amount indicating the change amount of the capacity of the storage element 200 in the first period from the first time point to the second time point is acquired as the two time points. Alternatively, the determination unit 110 sets the time point when the power storage element 200 is not charged and discharged to the other time as the first time point, or charges and discharges the power storage element 200 from the other time point. It is determined whether or not the first change amount is smaller than a predetermined amount, with the time point when the state is switched to the second time point being the second time point.

  More specifically, the switching determination unit 120 determines whether or not the storage element 200 has been switched from one of charging and discharging to the other, and whether or not the other has been switched to the one. Detect one time point and a second time point. Alternatively, the switching determination unit 120 detects the first time point or the second time point by determining whether or not the storage device 200 is switched from the left state to the other state, or whether or not the other is switched to the left state. To do.

  In other words, for example, as illustrated in FIG. 7, the switching determination unit 120 detects the time point when the discharge of the power storage element 200 is switched from discharging to charging as the first time point, and detects the time point when switching from charging to discharging is the second time point. Alternatively, for example, as illustrated in FIG. 8, the switching determination unit 120 detects a time point at which the storage element 200 is switched from being left to charging as a first time point, and detects a time point at which switching from charging to discharging is performed as a second time point. . Alternatively, for example, as illustrated in FIG. 9, the switching determination unit 120 detects the time point when the discharge of the power storage element 200 is switched from discharging to charging as the first time point, and the time point when switching from charging to a neglected state (state where the current is zero) Is detected as the second time point.

  Then, the change amount determination unit 130 acquires 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. That is, for example, as illustrated in FIG. 7, the change amount determination unit 130 acquires a first change amount indicating a change amount Q <b> 1 of the capacity of the power storage element 200 in the first period from the first time point to the second time point. 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 determination unit 110 determines whether or not the acquired first change amount is smaller than a predetermined amount (S104: determination step). Specifically, the change amount determination unit 130 determines whether or not the first change amount is smaller than a predetermined amount. That is, the change amount determination unit 130 uses the change amount of the SOC of the power storage element 200 in the first period as the first change amount, and determines whether or not the change amount of the SOC is smaller than a predetermined amount.

  That is, for example, as illustrated in FIG. 7, the change amount determination unit 130 calculates the amount of change Q1 of the capacity of the power storage element 200 by integrating the current in the first period (that is, multiplying the current and time). Then, change amount determination unit 130 calculates the SOC change amount of power storage element 200 corresponding to change amount Q1 as the first change amount, and determines whether the change amount of SOC is smaller than a predetermined amount. To 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 changed according to the situation instead of a fixed value. .

  When determining unit 110 determines that the first change amount is smaller than the predetermined amount (YES in S104), state estimating unit 140 reduces the first deterioration amount (S106: deterioration amount reducing step). Specifically, state estimation unit 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 it is determined that the first change amount is equal to or greater than a predetermined amount. The value is reduced to a value smaller than the value of the first deterioration amount obtained using the rule.

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

  And the state estimation part 140 estimates the state of the electrical storage element 200 (S108: state estimation step). When determining unit 110 determines that the first change amount is equal to or greater than the predetermined amount (NO in S104), state estimating unit 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 SOC change amount corresponding to the change amount Q2 is equal to or greater than a predetermined amount, the state estimation unit 140 performs 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 greater than the predetermined amount, the state estimation unit 140 calculates the deterioration amount using a predetermined relational expression or the like, and the determination unit 110 When 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, the state estimation part 140 estimates the state of the electrical storage element 200 by reducing the 1st degradation amount according to a condition.

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

  Next, details of a 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 will be described.

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

  If the switching determination unit 120 determines that the state of charge / discharge with respect to the power storage element 200 has not been switched (NO in S204), the switching determination unit 120 repeatedly performs the process of acquiring the average value of current for each unit period (S202). .

  When switching determination unit 120 determines that the state of charge / discharge of power storage element 200 has been switched (YES in S204), it acquires the first time point and the second time point (S206). Specifically, the switching determination unit 120 detects a time point at which one of charging and discharging of the power storage element 200 is switched to the other as the first time point, and the first time point is followed by the other to the one. The time of switching is detected as the second time. In addition, the switching determination unit 120 detects the time point when the storage element 200 is switched from the neglected state in which charging and discharging are not performed to the other as the first time point. Alternatively, the switching determination unit 120 also detects the time point when the other is switched to the neglected state as the second time point.

  Then, the change amount determination unit 130 calculates the change amount of the SOC as the first change amount (S208). That is, the change amount determination unit 130 uses the change amount of the SOC 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 switching determination unit 120 and the change amount determination unit 130 of the determination unit 110 complete the process of acquiring the first change amount (S102 in FIG. 4).

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

  As shown in FIG. 6, first, the state estimation unit 140 reduces the first deterioration amount in the first period (S302). That is, the state estimation 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 greater than the predetermined amount. Reduce. Specifically, for example, as illustrated in FIG. 7, the state estimation unit 140 reduces the first deterioration amount corresponding to the change amount Q1 of the capacity of the power storage element 200 to zero.

  Then, the state estimation unit 140 determines whether or not the second period having a change amount equal to or smaller than the first change amount is included in the predetermined third period in one state of charging and discharging. (S304). Specifically, for example, as illustrated in FIG. 7, the state estimation unit 140 determines whether or not the second period corresponding to the change amount Q3 having a magnitude equal to or less than the change amount Q1 is included in the third period. . The third period may be appropriately determined according to user settings. For example, the third period is 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. 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. In addition, the second period may be a period having a change amount that is equal to or less than the first change amount, but is preferably a period having a change amount that is the same as the first change amount. In other words, the change amount Q3 is preferably the same as the change amount Q1. However, in the case shown in FIG. 9, it is preferable that the amount of change Q3 is the same as the sum of the amounts of change Q4 and 5.

  If the state estimation unit 140 determines that the second period is included in the third period (YES in S304), the state estimation unit 140 reduces the second deterioration amount in the second period (S306). That is, the state estimation unit 140 determines the second deterioration amount in the second period having a change amount not greater than the first change amount in one state of charging and discharging, and the first change amount is a predetermined amount or more. Is reduced to a value smaller than the value of the second deterioration amount obtained by using the rule applied when it is determined that.

  For example, in FIG. 7, the state estimation unit 140 determines that the second period corresponding to the change amount Q3 having a magnitude equal to or smaller than the change amount Q1 is included in the third period. And the state estimation part 140 reduces the 2nd degradation amount of the 2nd period corresponding to the variation | change_quantity Q2 in a discharge state to zero.

  Here, when the second period is not one continuous period but includes a plurality of non-consecutive periods, the state estimation unit 140 determines that the total amount of change is not more than the first change amount. A second period consisting of periods is acquired, and a second deterioration amount indicating a deterioration amount due to energization of the power storage element 200 in each of the plurality of periods is reduced.

  That is, for example, as illustrated in FIG. 10, the state estimation unit 140 acquires a second period including a plurality of periods corresponding to the change amounts Q6 and 7 in which the total change amount is equal to or less than the change amount Q1. 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 change amount is the same as the first change amount (in FIG. 10, the sum of the change amounts Q6 and 7 is the same as the change amount Q1). preferable.

  If the state estimation unit 140 determines that the second period is not included in the third period (NO in S304), the state estimation unit 140 ends the process without reducing the second deterioration amount in the second period. . That is, for example, as illustrated in FIG. 11, when the state estimation 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. The process is terminated without reducing the amount.

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

  Next, the effect which the electrical storage element state estimation apparatus 100 has is demonstrated using FIG. 12A-FIG.

  FIG. 12A and FIG. 12B are diagrams showing premise data used to explain the effects 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 SOC variation calculated based on the current pattern. 13A to 13C are diagrams showing effects of the storage element state estimation device 100 according to the embodiment of the present invention. Specifically, FIG. 13A is a graph showing measured values and comparative examples, FIG. 13B is a graph showing measured values and examples, and FIG. 13C is measured values of comparative examples and examples. It is the table which compared the difference from. FIG. 14 is a conceptual diagram for explaining 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 (average of 4 seconds), which is a running mode for carrying out the fuel consumption calculation of the automobile. This current pattern was applied to the electricity storage device of the present application, and a test simulating actual use was performed. Also, FIG. 12B reads the timing at which the sign of the current value switches in the current pattern shown in FIG. Is. 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%. The change amount of the SOC is calculated by dividing the change amount of the capacity of the power storage element by the reversible capacity.

  Next, FIG. 13A to FIG. 13C show the results of a test simulating actual use in the above current pattern. That is, FIG. 13A shows an estimation result (comparative example 1) in the case of using a conventional power storage element state estimation apparatus that does not perform state estimation by the power storage element state estimation apparatus 100 in the above embodiment, and an actual measurement in the power storage element. The measured state value (measured value 1) is shown. Specifically, the figure shows the transition of the capacity of the electricity storage element 55, 109, 159, and 209 days after the start of the test. In addition, the comparative example 1 and the measured value 1 are the estimation result and measurement result in an environment 20 degreeC higher than normal temperature.

  Further, FIG. 13B shows an estimation result (Example 1) in the case where the power storage deterioration state when the amount of change in the SOC is less than 0.5% is set to zero by the power storage element state estimation device 100 in the above embodiment, and The state value actually measured (measured value 1) is shown. Specifically, the figure shows the transition of the capacity of the electricity storage element 55, 109, 159, and 209 days after the start of the test. In addition, Example 1 is an estimation result in the environment 20 degreeC higher than normal temperature when the electrical storage element state estimation apparatus 100 is used, and corresponds to the comparative example 1 and the measurement value 1 described above.

  FIG. 13C shows a table of test results of Comparative Example 1 shown in FIG. 13A and Example 1 shown in FIG. 13B. Specifically, the figure shows an error between the comparative example 1 and the measured value 1 and an error between the example 1 and the measured value 1. The error is calculated by dividing the difference in capacity by the initial capacity. As shown in these drawings, Example 1 has a smaller error from measurement value 1 than Comparative Example 1.

  As described above, since the deterioration of the battery is unlikely to proceed due to a minute change in the SOC, the estimation accuracy is improved by ignoring the deterioration due to the minute change in the SOC. For example, as shown in FIG. 14 (a), it is assumed that when the battery is discharged, charging equivalent to 20% SOC and discharging equivalent to 120% SOC (charging and discharging equivalent to SOC 140% in total) are performed. Of these, if the 20% charge and 20% discharge are due to a slight change in the SOC, the 20% charge and 20% discharge can be ignored. For this reason, as shown in FIG. 14 (b), it is assumed that the charge equivalent to 0% SOC and the discharge equivalent to 100% SOC have been performed ignoring the 20% charge and 20% charge. it can. Thereby, estimation accuracy can be improved.

In addition, the specification of the battery made into object by said test is as follows in all the Examples and the comparative examples. That is, as the battery specifications, spinel lithium manganese oxide was used as the positive electrode active material (positive electrode active material layer), acetylene black as the conductive additive, and polyvinylidene fluoride as the binder. The negative electrode mixture (negative electrode active material layer) used non-graphitizable carbon as the negative electrode active material and polyvinylidene fluoride as the binder. Further, EC (ethylene carbonate), EMC (ethyl methyl carbonate), and DMC (dimethyl carbonate) were mixed at a ratio of 25:55:20, and 1 mol / L of LiPF ₆ was added to the mixed solution. . Further, in the estimation of the battery capacity, for example, a model equation of deterioration in 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-described model expression for degradation is only an example, and any model that conforms to the gist of the present application belongs to the technical scope of the present invention.

  As described above, according to the storage element state estimation device 100 according to the embodiment of the present invention, the first change amount indicating the change amount of the capacity of the storage element 200 during the period when the charge / discharge of the storage element 200 is switched is: When it is determined that the amount is smaller than the predetermined amount, the state of the electricity storage element 200 is estimated by reducing the first deterioration amount indicating the amount of deterioration due to energization of the electricity storage element 200 from a value obtained by normal estimation calculation. 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, a small and complicatedly changing current is frequently superimposed, and the capacity changes slightly. It has been found that there is little influence on the amount of deterioration due to the 200 energization. That is, for example, in the case of a lithium ion battery, the deterioration due to energization of the storage element 200 is mainly caused by repeated expansion and contraction of the active material due to the insertion / desorption reaction of lithium ions into the active material. It is assumed that the mechanical contact between the active material particles becomes insufficient due to repeated destruction of the electrode plate or expansion and contraction of the electrode plate accompanying charging and discharging. However, when the amount of electricity is small, that is, when the SOC fluctuation is small, the degree of expansion and contraction accompanying this is very small, so that the above-described collapse of the crystal structure and reduction of mechanical contact proceed. It is assumed that no deterioration occurs. For this reason, according to the storage element state estimation device 100, the first deterioration amount when the capacity changes slightly is smaller than the value obtained by the normal estimation calculation, thereby estimating the state estimation accuracy of the storage element 200. Can be improved.

  Further, as a result of intensive studies, the inventors of the present application have found that the first deterioration amount when the capacity changes slightly can be ignored. Therefore, 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 estimation accuracy of the state of the power storage element 200 can be improved.

  In addition, the storage element state estimation device 100 reduces the second deterioration amount, which indicates the deterioration amount due to energization of the storage element 200 in the second period, from the value obtained by normal estimation calculation, thereby changing the state of the storage element 200. presume. Here, as a result of intensive studies, the inventors of the present application have found that both the charging and discharging have little influence on the deterioration amount due to energization of the power storage element 200 when the capacity changes minutely. Therefore, according to the storage element state estimation device 100, it is possible to improve the estimation accuracy of the state of the storage element 200 by reducing the deterioration amount in both charging and discharging.

  In addition, when the second period is divided into a plurality of periods, the storage element state estimation device 100 reduces the second deterioration amount indicating the deterioration amount due to energization of the storage element 200 in each of the plurality of periods. As described above, according to the storage element state estimation device 100, 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 storage element 200 by reducing the deterioration amount in the plurality of periods. Can do.

  In addition, the storage element state estimation device 100 reduces the second deterioration amount only when it is determined that the second period is included in the predetermined third period. That is, according to the storage element state estimation device 100, when the second period is not included in the third period, the deterioration amount can be prevented from being excessively reduced by not reducing the deterioration amount. The estimation accuracy of 200 states can be improved.

  In addition, the storage element state estimation device 100 can easily determine whether or not the direction of the current has been switched, thereby easily determining whether or not one of the charging and discharging has been switched to the other.

  Further, the storage element state estimation device 100 can eliminate the case where the direction of the current is frequently switched by determining whether the direction of the current is switched based on the average value of the current for each unit period.

  In addition, storage element state estimation device 100 uses the amount of change in SOC of storage element 200 in the first period as the first change amount, and determines whether or not the change amount of SOC is smaller than a predetermined amount. That is, according to the storage element state estimation device 100, it is possible to accurately determine whether or not to reduce the deterioration amount by using the SOC change amount as the first change amount.

  In addition, the storage element state estimation device 100 sets the time point when the storage element 200 is switched from the left state in which charging and discharging are not performed to the charge / discharge state in which charging or discharging is performed, or the charging / discharging state. The above determination is made with the time point when the state is changed to the neglected state as the second time point. As described above, according to the storage element state estimation device 100, the storage element can be reduced by reducing the deterioration amount even when the state is changed from the left state to the charge / discharge state or when the state is changed from the charge / discharge state to the left state. The estimation accuracy of 200 states can be improved.

  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 above, but the present invention is not limited to this embodiment. That is, the embodiment disclosed this time should be considered as illustrative in all points 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 embodiment, the change amount determination unit 130 determines whether or not the change amount of the SOC of the power storage element 200 in the first period is smaller than a predetermined amount. However, the change amount determination unit 130 may make the determination using the change amount of the capacity of the power storage element 200 or the change amount of DOD (Depth Of Discharge) instead of the change amount of the SOC. That is, the change amount determination unit 130 uses the change amount of the storage element 200 or the DOD in the first period as the first change amount, and determines whether or not the change amount of the capacitance or DOD is smaller than a predetermined amount. It may be.

  In the above embodiment, the state estimation unit 140 reduces the second deterioration amount only when it is determined that the second period is included in the third period. However, the state estimation unit 140 may reduce all the second deterioration amounts without setting the third period.

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

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

  Moreover, in the said embodiment, the switching determination part 120 determines whether the direction of the electric current with respect to the electrical storage element 200 was switched, and whether it switched from any one of charge and discharge with respect to the electrical storage element 200 to the other. It was decided to judge. However, the switching determination unit 120 may determine whether or not switching from one of charging and discharging to the other is based on other information such as information from the outside, not the direction of current.

  Further, in the above-described embodiment, the determination unit 110 sets the first change time as the first time point when switching from the left state to the charge / discharge state or the second time point when switching from the charge / discharge state to the left state. It was decided whether or not the amount was smaller than a predetermined amount. However, the determination unit 110 may not perform the determination when switching from the left state to the charge / discharge state or when switching from the charge / discharge state to the left state.

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

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

  Further, 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) that is an integrated circuit. That is, for example, as shown in FIG. 15, the present invention is realized as an integrated circuit 101 including a determination unit 110 and a state estimation unit 140. FIG. 15 is a block diagram showing a configuration for realizing the storage element state estimation apparatus 100 according to the embodiment of the present invention using an integrated circuit.

  Each processing unit included in the integrated circuit 101 may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used. Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. There is a possibility of adaptation of biotechnology.

  In addition, the present invention can be realized not only as such a storage element state estimation apparatus 100 but also as a storage element state estimation method that includes a characteristic process performed by the storage element state estimation apparatus 100 as a step. Can do.

  Further, the present invention is realized as a program for causing a computer (processor) to execute characteristic processing included in the storage element state estimation method, or a computer (processor) readable non-transitory 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 be realized as any medium. Such a program can be distributed via a recording medium such as a CD-ROM and a transmission medium such as the Internet.

  In addition, an embodiment constructed by arbitrarily combining the constituent elements included in the above embodiment is also included in the scope of the present invention.

  The present invention can be applied to a storage element state estimation device that can improve the estimation accuracy of the state of a storage element.

DESCRIPTION OF SYMBOLS 10 Power storage system 100 Power storage element state estimation apparatus 101 Integrated circuit 110 Determination part 120 Switching determination part 130 Change amount determination part 140 State estimation part 150 Storage part 151 Charging / discharging log | history data 152 Degradation information data 200 Power storage element 300 Storage case

Claims (7)

A storage element state estimation device for estimating a state of a storage element,
The time point when the storage element is switched from one of charging and discharging to the other is defined as the first time point, the time point when switching from the other time to the one after the first time point is defined as the second time point, and from the first time point A determination unit that determines whether or not a first change amount indicating a change amount of the capacity of the power storage element in the 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, a first deterioration amount indicating a deterioration amount due to energization of the power storage element in the first period is set to be greater than or equal to the predetermined amount. A storage element state comprising: a state estimation unit that estimates a state of the 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 Estimating device. The state estimation unit estimates the state of the power storage element by reducing the first deterioration amount to zero when it is determined that the first change amount is smaller than the predetermined amount. Storage element state estimation apparatus. The state estimation unit further indicates a deterioration amount due to energization of the power storage element in a second period having a change amount not greater than the first change amount in the one state of the charge and the discharge. Reducing the second deterioration amount 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 greater than the predetermined amount; The power storage element state estimation apparatus according to claim 1, wherein the state of the power storage element is estimated. The state estimation unit acquires the second period including a plurality of periods in which a total change amount is equal to or less than the first change amount, and calculates a deterioration amount due to energization of the power storage element in each of the plurality of periods. The electrical storage element state estimation apparatus according to claim 3, wherein the second deterioration amount is reduced. The state estimation unit determines whether or not the second period is included in a predetermined third period, and the second deterioration amount is determined only when it is determined that the second period is included in the third period. The electrical storage element state estimation apparatus according to claim 3 or 4. The determination unit sets the time point when the power storage element is not charged and discharged to the other time as the first time point, or charges and discharges the power storage element from the other side. The power storage element state estimation device according to any one of claims 1 to 5, wherein the second time point is set as a time point when the state is switched to an unexisting state, and it is determined whether or not the first change amount is smaller than the predetermined amount. A storage element state estimation method for estimating a state of a storage element,
The time point when the storage element is switched from one of charging and discharging to the other is defined as the first time point, the time point when switching from the other time to the one after the first time point is defined as the second time point, and from the first time point A determination step of determining whether or not a first change amount indicating a change amount of the capacity of the power storage element in the 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, a first deterioration amount indicating a deterioration amount due to energization of the power storage element in the first period is set to be greater than or equal to the predetermined amount. A state estimating step of estimating the state of the power storage element by reducing it to a value smaller than the value of the first deterioration amount obtained using a rule applied when it is determined that Estimation method.

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