JP6773195B2 - Power storage system and computer program - Google Patents

Description

The present invention relates to a power storage system and a computer program for estimating the state of a power 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 in recent years, they have come to be used in a wide range of fields such as power sources for electric vehicles. Conventionally, for such a power storage element, a technique for estimating the state of the power storage element based on information such as charge / discharge history has been proposed (see, for example, Patent Documents 1 and 2). In this technology, the life of the power storage element is predicted by using information such as charge / discharge history.

Japanese Unexamined Patent Publication No. 2013-89424 Japanese Unexamined Patent Publication No. 2014-81238

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

That is, for example, when the power storage element is operated in a substation or the like, minute and complicatedly changing currents are often superimposed, and the charge / discharge history becomes complicated. As a result of diligent studies, the inventors of the present application cannot accurately estimate the state of the power storage element when all the charge / discharge histories are calculated by the same mathematical formula when the charge / discharge history becomes complicated in this way. It was found that there is a risk that

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage system and a computer program capable of improving the estimation accuracy of the state of the power storage element.

In order to achieve the above object, the power storage system according to one aspect of the present invention is a power storage system including a power storage element and a power storage element state estimation device that estimates the state of the power storage element, and estimates the state of the power storage element. The apparatus has a first time point when one of charging and discharging of the power storage element is switched to the other, and a second time point when the other is switched to the other after the first time point. The determination unit for determining whether or not the first change amount indicating the change amount of the capacity of the power storage element in the first period from the first time point to the second time point is smaller than the predetermined amount, and the first change amount When it is determined that the amount is smaller than the predetermined amount, the first deterioration amount indicating the deterioration amount due to energization of the power storage element in the first period is determined to be equal to or more than the predetermined amount. A state estimation 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 by using the rule applied in the case is provided.

According to this, when the power storage element state estimation 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 when the charge / discharge of the power storage element is switched is smaller than the predetermined amount. In addition, the state of the power storage element is estimated by reducing the first deterioration amount, which indicates the amount of deterioration due to energization of the power storage element, from the value obtained by ordinary estimation calculation. Here, as a result of diligent studies, the inventors of the present application have found that when the power storage element is operated in a substation or the like, a minute and complicatedly changing current is often superimposed, and the capacity changes minutely, the power storage element It was found that the effect of energization on the amount of deterioration is small. Therefore, according to the power storage element state estimation device provided in the power storage system, the first deterioration amount when the capacity is slightly changed is reduced from the value obtained by the usual estimation calculation, so that the state of the power storage element is changed. The estimation accuracy can be improved.

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

Further, as a result of diligent studies, the inventors of the present application have found that the first deterioration amount when the capacity is slightly changed 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 a predetermined amount, the state of the power storage element is estimated by reducing the first deterioration amount to zero to store electricity. The accuracy of estimating the state of the element can be improved.

Further, the state estimation unit further deteriorates by energization of the power storage element in the second period having a change amount having a magnitude equal to or less than the first change amount in the one state of the charging and the discharging. The second deterioration amount indicating the above 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 the first change amount is 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 estimation device reduces the second deterioration amount, which indicates the deterioration amount due to energization of the power storage element in the second period, from the value obtained by the usual 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 slightly changed, both charging and discharging have little influence on the amount of deterioration due to energization of the power storage element. Therefore, 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 estimation unit acquires 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 the 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 the second deterioration amount indicating the deterioration amount due to the 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, the accuracy of estimating the state of the power storage element can be improved 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 the predetermined third period, and only when it is determined that the second period is included in the third period, the second period is included. The amount of deterioration may be reduced.

According to this, the power 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 power 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 is not reduced too much. The accuracy of state estimation can be improved.

Further, the determination unit sets the time when the power storage element is not charged and discharged to the other as the first time point, or charges and discharges the power storage element from the other. 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 switched to the non-performing state as the second time point.

According to this, the power storage element state estimation device sets the time when the power storage element is switched from the uncharged state in which the power storage element is not charged and discharged to the charged / discharged state in which the power storage element is charged or discharged as the first time point, or is charged or discharged. The above judgment is made with the time when the state is switched to the neglected state as the second time point. As described above, according to the power storage element state estimation device, even when the state is changed from the left state to the charged / discharged state or the state is changed from the charged / discharged state to the left state, the amount of deterioration of the power storage element is reduced. The accuracy of state estimation can be improved.

Further, the present invention can also be realized as a storage element state estimation method in which a characteristic process performed by the power storage element state estimation device included in the power storage system is a step. 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 is realized as a program for causing a computer to execute a characteristic process included in the 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.

According to the power storage system according to the present invention, the accuracy of estimating the state of the power storage element can be improved.

It is external drawing of the power storage system including the power storage element state estimation device which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of the power 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 charge / discharge history data which concerns on embodiment of this invention. It is a flowchart which shows an example of the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the process which the switching determination part and the change amount determination part of the determination part which concerns on embodiment of this invention acquire the 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 the first deterioration amount. It is a figure explaining the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure explaining the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure explaining the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure explaining the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure explaining the process of estimating the state of a power storage element by the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the premise data used for explaining the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the premise data used for explaining the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a figure which shows the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a conceptual diagram for demonstrating the effect of the power storage element state estimation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure which realizes the energy storage element state estimation apparatus which concerns on embodiment of this invention by an integrated circuit.

Hereinafter, the power storage element state estimation device according to the embodiment of the present invention and the power storage system including the power storage element state estimation device will be described with reference to the drawings. In addition, all the embodiments described below show a preferable specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level 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 of (five in the figure) 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. It includes a device 100 and a storage case 300 that houses a plurality of power storage elements 200. That is, one power storage element state estimation device 100 is arranged corresponding to one power storage element 200.

Each of the power storage element state estimation devices 100 is a flat plate-shaped circuit board arranged above the power storage element 200 and equipped with a circuit for estimating the state of the power storage element 200 at a predetermined time point. 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 at a predetermined time point of the one power storage element 200. Estimate a state such as a deteriorated state.

Here, the power storage element state estimation device 100 is arranged above each power storage element 200, but the power storage element state estimation device 100 may be arranged anywhere. Further, the shape of the power storage element state estimation device 100 is not particularly limited.

Further, the number of the power storage element state estimation devices 100 is not limited to 5, and may be a plurality of other devices or one. That is, one power storage element state estimation device 100 may be arranged corresponding to the 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. You may be. That is, the configuration may be such that a number of power storage element state estimation devices 100 are connected to a number of power storage elements 200. A detailed description of the functional configuration of the power storage element state estimation device 100 will be described later.

The power storage element 200 is a secondary battery capable of charging electricity and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. Further, in the figure, five rectangular power storage elements 200 are arranged in series to form an assembled battery. The number of power storage elements 200 is not limited to five, and may be a plurality of other elements or one. Further, the shape of the power storage element 200 is not particularly limited, and may be a cylindrical shape, a long cylindrical shape, or the like.

The power storage element 200 includes a container and electrode terminals (positive electrode terminal and negative electrode terminal) projecting from the container, and the electrode body, the electrode body, and the electrode terminal are connected to the inside of the container. A current collector (positive electrode current collector and negative electrode current collector) is arranged, and a liquid such as an electrolytic solution is sealed therein. The electrode body is formed by winding a positive electrode, a negative electrode, and a separator. The electrode body may not be a wound type electrode body, but may be a laminated type electrode body in which flat plate-shaped electrode plates are laminated.

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, any known material can be appropriately used as long as it is a positive electrode active material capable of occluding and releasing lithium ions. For example, as the positive electrode active material, a polyanionic 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. A lithium transition metal oxide 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 which is a long strip-shaped metal foil made of copper, a copper alloy, or the like. As the 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 that can occlude and release lithium ions. For example, as the 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) In addition, alloys capable of storing and releasing lithium, carbon materials (for example, graphite, non-graphitized carbon, easily graphitized carbon, low-temperature calcined carbon, amorphous carbon, etc.), silicon oxide, metal oxide, lithium metal oxide (Li ₄ Ti ₅ O _12, etc.), polyphosphate compounds, or compounds of transition metals and Group 14 to Group 16 elements such as Co ₃ O ₄ and Fe ₂ P, which are generally called conversion negatives. Be done.

The separator is a microporous sheet made of resin. The separator used in the power storage element 200 is not particularly different from the conventionally used one, and a known material can be appropriately used as long as it does not impair the performance of the power storage element 200. Further, the type of electrolytic solution (non-aqueous electrolyte) sealed in the container is not particularly limited as long as it does not impair the performance of the power storage element 200, and various types can be selected.

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

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

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

The power storage element state estimation device 100 is a device that estimates the state of the power 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 the degree of deterioration of the performance of the power storage element 200, and the power storage element 200 exhibiting abnormal behavior. Includes abnormal conditions that indicate whether or not.

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. Further, the determination unit 110 includes a switching determination unit 120 and a change amount determination unit 130. Further, 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 has a first time point when either one of charging and discharging of the power storage element 200 is switched to the other, and a second time point when the other is switched to the other after the first 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 the first time point to the second time point is smaller than the predetermined amount. Further, the determination unit 110 charges and discharges the power storage element 200 from the first time point when the state where the power storage element 200 is not charged and discharged is switched to the other. It may be determined whether or not the first change amount is smaller than the predetermined amount, with the time when the state is switched to the non-existing state as the second time point.

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

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

First, the switching determination unit 120 acquires the charge / discharge history of the power storage element 200 up to the time when the state of the power storage element 200 is to be estimated (hereinafter referred to as a predetermined time). Specifically, the switching determination unit 120 is connected to the power storage element 200, and detects and acquires the charge / discharge history from the 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 mounted by wiring such as a lead wire. Then, the switching determination unit 120 acquires the charge / discharge history from the power storage element 200 via the wiring in the period up to the predetermined time point.

More specifically, the switching determination unit 120 constantly monitors the operating state of the power storage element 200, and acquires the 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, it considers that the power storage element 200 has charged and discharged, and charges the battery. Get the discharge history. In this case, for example, the switching determination unit 120 acquires the charge / discharge history each time the change in the voltage of the power storage element 200 exceeds 0.1%. That is, the switching determination unit 120 acquires the charge / discharge history in a sampling cycle in which the change in the voltage of the power storage element 200 is 0.1%. The timing of acquiring the charge / discharge history is not limited to the above, and the switching determination unit 120 acquires the charge / discharge history in a sampling cycle in which the power storage element 200 is used for 1 second. You may use. When the sampling cycle is set to a fixed period, a cycle of 1 second or less is preferable.

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

Specifically, the information indicating the charge / discharge time point is information including the date (year / month / day) and time when the power storage element 200 is charged or discharged. Further, the information regarding charging or discharging performed by the power storage element 200 is information indicating a voltage and current at the time of charging or discharging performed by the power 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. The unit period may be any period and may be appropriately determined by the user's setting. For example, the unit period is 1 second, 4 seconds, 30 seconds, 1 minute, etc., but 4 seconds is preferable. Further, for example, when the power storage element 200 is being charged, the switching determination unit 120 makes the current value positive, and when the power storage element 200 is being discharged, the current value is set. Is negative, and the average value of the current is calculated.

In addition, the switching determination unit 120 uses SOC (State) of the power storage element 200 for each unit period.
Of Charge) is calculated and acquired. For example, the switching determination unit 120 calculates the SOC by estimating the SOC from the voltage value of the power storage element 200 by using the SOC-OCV characteristic showing the relationship between the SOC and the OCV (Open Circuit Voltage). To do. Alternatively, the switching determination unit 120 may calculate the SOC from the current value of the power storage element 200 by using the current integration method in which the charge / discharge current is integrated to estimate the SOC.

Then, the switching determination unit 120 stores the acquired information indicating the charge / discharge time point, 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, 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 by 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 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, for example. Is judged to have been switched.

Then, 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, and thus determines whether or not either charging or discharging of the power storage element 200 has been switched to the other. That is, the switching determination unit 120 determines that when the current value changes from plus to minus, it has switched from charging to discharging, and when the current value changes from minus to plus, it determines that it has switched from discharging to charging. To do.

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

Further, the switching determination unit 120 also detects a time when the power storage element 200 is switched from a state in which the power storage element 200 is not charged or discharged (hereinafter referred to as a neglected state) to the other state as the first time point. Alternatively, the switching determination unit 120 also detects the time when the other side is switched to the neglected state as the second time point.

That is, the switching determination unit 120 detects the time point when the current value changes from zero to plus or minus as the first time point, and also when the current value changes from minus or plus to zero, the second time point. Is detected. In addition, there is a case where a minute current always flows through the power storage element 200. In this case, not only the value of the current is zero, but also when the current is below a certain value, the concept of the neglected state. Include in. Moreover, even if the period in which the current value is zero is momentary, it is included in the concept of the neglected state.

Then, the switching determination unit 120 sets the charge / discharge state (charge, discharge, or neglect) of the power storage element 200 for each unit period and the detected switching time (first time, second time) as charge / discharge history data 151. Write further 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 power storage element 200 up to a predetermined time point, is written in the charge / discharge history data 151. 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 point", a date (year / month / day), a time, and the like, which are information indicating a time point when the power storage element 200 is 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), the time, etc., and writes it in the “charge / discharge time point”. Any unit such as year, month, day, hour, minute, second, or number of cycles (number of charge / discharge) may be used as the unit at the time of charge / discharge.

Further, the "voltage (mean value)", "current (mean value)" and "SOC" include the unit period during charging or discharging performed by the power storage element 200 as information regarding charging or discharging performed by the power storage element 200. Information indicating the average value of the voltage, the average value of the current, and the SOC in the above is stored. Further, in the "charge / discharge state", any one of "charge", "discharge", and "leaving" information is stored. Further, in the "switching time point", the switching time point (first time point, second time point) detected by the switching determination unit 120 is stored.

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

The change amount determination unit 130 indicates 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 the first time point to the second time point detection detected by the switching determination unit 120 is smaller than a predetermined amount. To judge.

Specifically, the change amount determination unit 130 sets 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 the predetermined amount. That is, the change amount determination unit 130 reads out 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 in the first period The amount of change in SOC of 200 is calculated and used as the first amount of change. Then, the change amount determination unit 130 determines whether or not the first change amount is smaller than the predetermined amount. The predetermined amount is, for example, a small value of about 0.5% or 0.36%.

Next, the processing 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 determines that the first change amount indicates the deterioration amount due to the energization of the power storage element 200 in the first period, and the first change amount is a predetermined amount. The value is reduced to a value smaller than the value of the first deterioration amount obtained by using the rule applied when it is judged that the above is the case. Here, the "first deterioration amount indicating the amount of deterioration of the power storage element 200 due to energization" is the amount of deterioration in performance caused by the power storage element 200 being energized. For example, the capacity of the power storage element 200 and the capacity retention rate. , SOC, voltage deterioration amount (decrease amount), capacity reduction rate, and the like.

Further, "the value of the first deterioration amount obtained by using the rule applied when it is determined that the first change amount is equal to or more than a predetermined amount" is defined by the change amount determination unit 130 as the first change amount. It is a value of the amount of deterioration calculated according to a mathematical formula or the like used when it is judged that the amount is 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, the state estimation unit 140 uses a predetermined relational expression to calculate the deterioration amount. It is a value of the amount of deterioration calculated using the relational expression. The state estimation unit 140 may calculate the deterioration amount by using a general relational expression conventionally known as the relational expression, or the state estimation unit 140 may use a new relational expression. May be derived to calculate the amount of deterioration.

That is, when the state estimation unit 140 determines that the change amount of the SOC 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, and the change amount determination unit 130. When it is determined that the amount of change in SOC is smaller than the predetermined amount, the amount of deterioration is reduced to a value calculated by 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 the 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 by using the above-mentioned predetermined relational expression. Alternatively, the amount of deterioration may be reduced to about 50% to 10%.

Further, the state estimation unit 140 further indicates the amount of deterioration due to energization of the power storage element 200 in the second period having a change amount having a magnitude of change equal to or less than the first change amount in one of the charging and discharging states. The amount of deterioration is reduced to a value smaller than the value of the second amount of deterioration obtained by using the rules applied when it is determined that the first amount of change is equal to or greater than a predetermined amount. That is, if the first period was charged, the second period was discharged, and if the first period was discharged, the second period was 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 separated from the first period. The second period may be a period having a change amount having a magnitude equal to or less than that of the first change amount, but is preferably a period having a change amount having the same magnitude as the first change amount.

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

Further, 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 me. 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 capable of reducing the second deterioration amount to the case where the second period is included in the third period. 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 that exceeds the third period, the amount of deterioration is reduced to the one that originally caused a large capacitance change. There is a possibility of letting you. However, such a possibility can be eliminated by setting the period for reducing the amount of deterioration 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 the predetermined time point from the deterioration information data 152, and estimates the state of the power storage element 200 at the predetermined time point. Specifically, the state estimation unit 140 estimates a deteriorated state indicating the degree of deterioration of the performance of the power storage element 200, an abnormal state indicating whether the power storage element 200 exhibits abnormal behavior, and the like. For example, the state estimation unit 140 estimates the deterioration state of the capacity such as what percentage the reversible capacity of the power storage element 200 is reduced. Then, the state estimation unit 140 writes the result of estimating the state of the power storage element 200 in the deterioration information data 152.

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

First, as shown in FIG. 4, the determination unit 110 acquires the first change amount indicating the 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 the time when either one of charging and discharging of the power storage element 200 is switched to the other as the first time point, and the time when the other is switched to the other after the first time point is the first time point. Two time points are set, and 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 is acquired. Alternatively, the determination unit 110 charges and discharges the power storage element 200 from the other side as the first time point when the state in which the power storage element 200 is not charged and discharged is switched to the other. It is determined whether or not the first change amount is smaller than the predetermined amount, with the time when the state is switched to the non-existing state as the second time point.

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

That is, for example, as shown in FIG. 7, the switching determination unit 120 detects the time when the power storage element 200 is switched from discharging to charging as the first time point, and detects the time when charging is switched to discharging as the second time point. Alternatively, as shown in FIG. 8, for example, the switching determination unit 120 detects the time when the power storage element 200 is switched from the neglected state to charging as the first time point, and detects the time when charging is switched to discharging as the second time point. .. Alternatively, for example, as shown in FIG. 9, the switching determination unit 120 detects the time when the power storage element 200 is switched from discharging to charging as the first time point, and when the charging is switched to the 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 detection detected by the switching determination unit 120. That is, for example, as shown in FIG. 7, the change amount determination unit 130 acquires the first change amount indicating the change amount Q1 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 by which the determination unit 110 (switching determination unit 120 and 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 the predetermined amount (S104: determination step). Specifically, the change amount determination unit 130 determines whether or not the first change amount is smaller than the predetermined amount. That is, the change amount determination unit 130 sets 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 the predetermined amount.

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

Then, when the determination unit 110 determines that the first change amount is smaller than the predetermined amount (YES in S104), the state estimation unit 140 reduces the first deterioration amount (S106: deterioration amount reduction step). Specifically, the state estimation unit 140 is applied when it is determined that the first change amount is equal to or more than a predetermined amount for the first deterioration amount indicating the deterioration amount due to energization of the power storage element 200 in the first period. Reduce to a value smaller than the value of the first deterioration amount obtained by using the rule.

That is, for example, as shown in FIG. 7, when the determination unit 110 determines that the change amount of the SOC corresponding to the change amount Q1 is smaller than the predetermined amount, the state estimation unit 140 corresponds to the change amount Q1. (1) Reduce the amount of deterioration. The details of the process by which the state estimation unit 140 reduces the first deterioration amount will be described later.

Then, the state estimation unit 140 estimates the state of the power storage element 200 (S108: state estimation step). When the determination unit 110 determines that the first change amount is equal to or greater than a predetermined amount (NO in S104), the state estimation unit 140 does not reduce the first deterioration amount, but the state of the power storage element 200. To estimate. For example, as shown 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 a predetermined amount, the state estimation unit 140 first deteriorates corresponding to the change amount Q2. The amount is calculated using a predetermined relational expression or the like without reducing the amount.

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 determines that the amount of deterioration is the first. When it is determined that the amount of change is smaller than the predetermined amount, the amount of deterioration is reduced from the value calculated by using a predetermined relational expression or the like. In this way, the state estimation unit 140 estimates the state of the power storage element 200 by reducing the first deterioration amount according to the situation.

As described above, the process of estimating the state of the power storage element 200 by the power storage element state estimation device 100 is completed. The power storage element state estimation device 100 can also estimate the state (remaining life, etc.) of the power storage element 200 in the future 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 acquire the first change amount will be described.

As shown in FIG. 5, first, the switching determination unit 120 acquires the average value of the current for each predetermined unit period (S202). Then, the switching determination unit 120 determines whether or not the charging / discharging state of the power storage element 200 has been switched by 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, and thus determines whether or not either charging or discharging of the power storage element 200 has been switched to the other. Alternatively, the switching determination unit 120 determines whether or not the current value has changed from zero to plus or minus, or whether or not the value has changed from minus or plus to zero, so that the state is left unattended and the state is charged or discharged. Determine if you have switched from one to the other.

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

Then, when the switching determination unit 120 determines that the charge / discharge state of the power storage element 200 has been switched (YES in S204), the switching determination unit 120 acquires the first time point and the second time point (S206). Specifically, the switching determination unit 120 detects the time when either charging or discharging of the power storage element 200 is switched to the other as the first time point, and then from the other side to the other side after the first time point. The time when the switch is made is detected as the second time. Further, the switching determination unit 120 also detects as the first time point when the power storage element 200 is switched from the neglected state in which the power storage element 200 is not charged or discharged to the other. Alternatively, the switching determination unit 120 also detects the time when the other side 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 sets 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 detection detected by the switching determination unit 120. calculate.

As a result, the process of acquiring the first change amount by the switching determination unit 120 and the change amount determination unit 130 of the determination unit 110 (S102 in FIG. 4) is completed.

Next, the 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 by using the rule applied when it is determined that the first change amount is equal to or more than a predetermined amount. Reduce. Specifically, for example, as shown 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 having a magnitude equal to or less than the first change amount 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 estimation unit 140 determines whether or not the second period corresponding to the change amount Q3 having a magnitude of the change amount Q1 or less is included in the third period. .. The third period may be appropriately determined according to the user's settings, but is, for example, 1 minute, 10 minutes, 1 hour, and the like, preferably 30 minutes or more and 1 hour or less.

Here, since the first period is the period in which the battery was charged, the second period is the period in which the battery was discharged. Further, the second period is preferably a period immediately before or immediately after the first period, but as shown in FIG. 9, it may be a period slightly separated from the first period. The second period may be a period having a change amount having a magnitude equal to or less than that of the first change amount, but is preferably a period having a change amount having the same magnitude as the first change amount. That is, the amount of change Q3 is preferably the same as the amount of change Q1. However, in the case of FIG. 9, it is preferable that the change amount Q3 has the same magnitude as the total of the change amounts Q4 and 5.

Then, when 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 having a magnitude equal to or less than the first change amount in one of the charging and discharging states, and the first change amount is a predetermined amount or more. The value is reduced to a value smaller than the value of the second deterioration amount obtained by using the rule applied when it is determined to be.

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 less than the change amount Q1 is included in the third period. Then, the state estimation unit 140 reduces the second deterioration amount in the second period corresponding to the change amount Q2 in the discharged state to zero.

Here, when the second period is not one continuous period but a plurality of discontinuous periods, the state estimation unit 140 has a plurality of states in which the total change amount is equal to or less than the first change amount. A second period consisting of periods is acquired, and the second deterioration amount indicating the 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 shown 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 consists of a plurality of periods in which the total amount of change is the same as the first amount of change (in FIG. 10, the total of the amounts of change Q6 and 7 is the same as the amount of change Q1). preferable.

Further, when 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 shown 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 is included. The process is terminated without reducing the amount.

As a result, the process of reducing the first deterioration amount by the state estimation unit 140 (S106 in FIG. 4) is completed.

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

12A and 12B are diagrams showing premise data used for explaining the effect of the power storage element state estimation device 100 according to the embodiment of the present invention. Specifically, FIG. 12A is a diagram showing a current pattern of the target battery, and FIG. 12B is a diagram showing a distribution of the amount of change in SOC calculated based on the current pattern. 13A to 13C are diagrams showing the effect of the power storage element state estimation device 100 according to the embodiment of the present invention. Specifically, FIG. 13A is a graph showing a measured value and a comparative example, FIG. 13B is a graph showing a measured value and an example, and FIG. 13C is a graph showing the measured value and the comparative example. It is a table comparing the differences from. Further, FIG. 14 is a conceptual diagram for explaining the effect of the 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 (4 second average), which is a traveling mode for performing the fuel consumption calculation of the automobile. This current pattern was applied to the power storage element of the present application, and a test simulating actual use was carried out. Further, in FIG. 12B, in the current pattern shown in FIG. 12A, the timing at which the sign of the current value is switched is read, the amount of change in SOC (ΔSOC) is calculated, and the values of the amount of change in SOC are arranged in ascending order. It is a thing. From this result, the maximum value of the change in SOC due to charging was 0.36%, which was extremely small, less than 0.5%. The amount of change in SOC is calculated by dividing the amount of change in the capacity of the power storage element by the reversible capacity.

Next, the results of carrying out a test simulating actual use in the above current pattern are shown in FIGS. 13A to 13C. That is, FIG. 13A shows an estimation result (Comparative Example 1) in the case of using a conventional power storage element state estimation device that does not perform state estimation by the power storage element state estimation device 100 in the above embodiment, and actual measurement by the power storage element. It shows the state value (measured value 1). Specifically, the figure shows changes in the capacity of the power storage element 55, 109, 159, and 209 days after the start of the test. Comparative Example 1 and the measured value 1 are estimation results and measurement results in an environment 20 ° C. higher than normal temperature.

Further, FIG. 13B shows an estimation result (Example 1) when the amount of conduction deterioration in which the amount of change in 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 power storage element. It shows the actually measured state value (measured value 1). Specifically, the figure shows changes in the capacity of the power storage element 55, 109, 159, and 209 days after the start of the test. Note that Example 1 is an estimation result in an environment 20 ° C. higher than normal temperature when the power storage element state estimation device 100 is used, and corresponds to the above-mentioned Comparative Example 1 and the measured value 1.

Further, FIG. 13C shows a table showing the test results of Comparative Example 1 shown in FIG. 13A and Example 1 shown in FIG. 13B. Specifically, the figure shows an error between Comparative Example 1 and the measured value 1, and an error between Example 1 and the measured value 1. The error is calculated by dividing the difference in capacitance by the initial capacitance. 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 is unlikely to proceed due to the 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. 14A, it is assumed that when the battery is discharged, the battery is charged with an SOC of 20% and discharged with an SOC of 120% (charge / discharge equivalent to a total SOC of 140%). If the 20% charge and the 20% discharge are due to a minute change in the SOC, the 20% charge and the 20% discharge can be ignored. Therefore, as shown in FIG. 14 (b), it is possible to estimate that the charge equivalent to SOC 0% and the discharge equivalent to SOC 100% were performed, ignoring the charge 20% and the discharge 20%. it can. Thereby, the estimation accuracy can be improved.

The specifications of the batteries targeted in the above test are as follows in all the examples and comparative examples. That is, as a battery specification, spinel-type lithium manganese oxide was used as the positive electrode active material, acetylene black was used as the conductive auxiliary agent, and polyvinylidene fluoride was used as the binder for the positive electrode mixture (positive electrode active material layer). Further, as the negative electrode mixture (negative electrode active material layer), non-graphitized 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 electrolytic solution at a ratio of 25:55:20, and 1 mol / L of LiPF ₆ was added to the mixed solution. .. Further, in estimating the battery capacity, for example, the model formula of deterioration in the usage period t when the deterioration coefficient is a can be calculated as f (t) = a√t. The above model formula for deterioration is only an example, and if it is in line with the gist of the present application, it belongs to the technical scope of the present invention.

As described above, according to the power storage element state estimation device 100 included in the power storage system 10 according to the embodiment of the present invention, the amount of change in the capacity of the power storage element 200 during the period when the charge / discharge of the power storage element 200 is switched is shown. When it is determined that the amount of change 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 the value obtained by the usual estimation calculation, and the power storage element 200 Estimate the state. Here, as a result of diligent 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 changes minutely, the power storage element It was found that the influence of the energization of 200 on the amount of deterioration is small. That is, in the case of a lithium ion battery, for example, the deterioration of the power storage element 200 due to energization is a crystal structure due to repeated expansion and contraction of the active material mainly due to the insertion / desorption reaction of lithium ions into the active material. It is presumed that this is caused by insufficient mechanical contact between the active material particles due to repeated expansion and contraction of the electrode plate due to the destruction of the active material or the repeated expansion and contraction of the electrode plate due to charging and discharging. However, when the amount of energized electricity is small, that is, when the SOC fluctuation is small, the degree of expansion and contraction accompanying this is small, so that the above-mentioned collapse of the crystal structure and reduction of mechanical contact proceed. It is assumed that deterioration will not occur without it. 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 the value obtained by the usual estimation calculation, so that the power storage element 200 It is possible to improve the estimation accuracy of the state of.

Further, as a result of diligent studies, the inventors of the present application have found that the first deterioration amount when the capacity is slightly changed can be ignored. Therefore, according to the power 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 power storage element 200 is estimated by reducing the first deterioration amount to zero. , It is possible to improve the estimation accuracy of the state of the power storage element 200.

Further, the power storage element state estimation device 100 reduces the second deterioration amount, which indicates the deterioration amount due to energization of the power storage element 200 in the second period, from the value obtained by the usual estimation calculation, and changes the state of the power storage element 200. presume. Here, as a result of diligent studies, the inventors of the present application have found that when the capacity is slightly changed, both charging and discharging have little influence on the amount of deterioration due to energization of the power storage element 200. Therefore, according to the power storage element state estimation device 100, the accuracy of estimating the state of the power storage element 200 can be improved by reducing the amount of deterioration in both charging and discharging.

Further, 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 the energization of the power storage element 200 in each of the plurality of periods. As described above, according to the power storage element state estimation device 100, even when the second period is divided into a plurality of periods, the state estimation accuracy of the power storage element 200 can be improved by reducing the amount of deterioration in the plurality of periods. Can be done.

Further, the power 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 power storage element state estimation device 100, when the second period is not included in the third period, the deterioration amount is not reduced, so that the deterioration amount is not reduced too much. The estimation accuracy of the 200 states can be improved.

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

Further, the power storage element state estimation device 100 can eliminate the case where the current direction is frequently switched by determining whether or not the current direction is switched based on the average value of the current for each unit period.

Further, the power storage element state estimation device 100 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 the predetermined amount. That is, according to the power storage element state estimation device 100, by using the change amount of SOC as the first change amount, it is possible to accurately determine whether or not to reduce the deterioration amount.

Further, the power storage element state estimation device 100 sets the time when the power storage element 200 is switched from the uncharged state of not charging and discharging to the charging / discharging state of charging or discharging as the first time point, or the charging / discharging state. The above judgment is made with the time when the state is switched to the left state as the second time point. As described above, according to the power storage element state estimation device 100, even when the state is changed from the left state to the charged / discharged state or the state is changed from the charged / discharged state to the left state, the amount of deterioration is reduced to reduce the amount of deterioration of the power storage element. The estimation accuracy of 200 states can be improved.

Although 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, the present invention is not limited to this embodiment. That is, it should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

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 the predetermined amount. However, the change amount determination unit 130 may make a determination by using the change amount of the capacity of the power storage element 200 or the change amount of the DOD (Deepth Of Discharge) instead of the change amount of the SOC. That is, the change amount determination unit 130 sets the change amount of the capacity or DOD 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 capacity or DOD is smaller than the predetermined amount. It may be.

Further, in the above embodiment, the state estimation unit 140 decides to reduce 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 amount without setting the third period.

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

Further, in the above embodiment, the switching determination unit 120 acquires the average value of the current for each unit period, and uses the average value to determine whether or not the direction of the current with respect to the power storage element 200 has been switched. 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.

Further, in the above embodiment, 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, and thus whether or not one of charging and discharging of the power storage element 200 has been switched to the other. Was decided to judge. However, the switching determination unit 120 may determine whether or not 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 makes a first change with the time point at which the charge / discharge state is switched to the charge / discharge state as the first time point or the time point at which the charge / discharge state is switched to the leave state as the second time point. It was decided to judge whether the amount was smaller than the predetermined amount. However, the determination unit 110 may not make the determination when the state of neglect is switched to the state of charge / discharge or the state of charge / discharge is switched to the state of neglect.

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

Further, the power storage element state estimation device 100 has a function of referring to the estimated data regarding the state of the power storage element 200, detecting an abnormality of the power storage element 200, and estimating a safety state such as issuing a safety alarm. You may be.

Further, the processing unit included in the power 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 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 in which the power storage element state estimation device 100 according to the embodiment of the present invention is realized by an integrated circuit.

Each processing unit included in the integrated circuit 101 may be individually integrated into one chip, or may be integrated into one chip so as to include a part or all of the processing units. Although it is referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. Further, the method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of the circuit cells inside the LSI may be used. Furthermore, if an integrated circuit technology that replaces an LSI appears due to advances in semiconductor technology or another technology derived from it, it is naturally possible to integrate functional blocks using that technology. There is a possibility of adaptation of biotechnology.

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

Further, the present invention is realized as a program for causing a computer (processor) to execute a characteristic process included in the storage element state estimation method, or a computer (processor) readable non-temporary recording in which the program is recorded. Mediums such as flexible disks, hard disks, CD-ROMs, MOs, DVDs, DVD-ROMs, DVD-RAMs, BDs (Blu-ray® Disc), semiconductor memories, flash memories, magnetic storage devices, optical disks, paper tapes. 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 form constructed by arbitrarily combining the components included in the above-described embodiment is also included in the scope of the present invention.

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

10 Power storage system 100 Power storage element state estimation device 101 Integrated circuit 110 Judgment unit 120 Switching judgment unit 130 Change amount judgment unit 140 State estimation unit 150 Storage unit 151 Charging / discharging history data 152 Deterioration information data 200 Power storage element 300 Storage case

Claims (2)

A power storage system including a power storage element and a power storage element state estimation device that estimates the state of the power storage element.
The power storage element state estimation device is
The time when one of charging and discharging of the power storage element is switched to the other is defined as the first time point, and the time when the other is switched to the other after the first time point is set as the second time point. A determination unit for determining whether or not 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 indicates the deterioration amount due to energization of the power storage element in the first period, and the first change amount is equal to or more than the predetermined amount. A power storage system including a state estimation unit that estimates the state of the power storage element by reducing the value to a value smaller than the value of the first deterioration amount obtained by using a rule applied when it is determined to be. .. A computer program that allows a computer to estimate the state of a power storage element.
On the computer
The time when one of charging and discharging of the power storage element is switched to the other is defined as the first time point, and the time when the other is switched to the other after the first time point is set as the second time point. Judgment processing for determining whether or not 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, and
When it is determined that the first change amount is smaller than the predetermined amount, the first change amount indicates the deterioration amount due to energization of the power storage element in the first period, and the first change amount is equal to or more than the predetermined amount. A computer program that executes a state estimation process 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 by using the rule applied when it is determined to be. ..

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