Prediction device, power storage device, prediction method, and prediction program

Abstract

The present invention is provided with: a first prediction unit that predicts, using a power storage element model, the voltage behavior of a power storage element when energized in a predetermined energization pattern; and a second prediction unit that predicts the charge / discharge performance of the electricity storage element on the basis of the voltage behavior predicted by the first prediction unit. The first prediction unit predicts the voltage behavior for each interval in which the energization pattern is divided by a time width, and stops the prediction of the voltage behavior in an interval in which an amount of change in current in the energization pattern is less than a threshold value.

Description

TECHNICAL FIELD

[0001] The present application relates to a prediction device, an electric power storage device, a prediction method, and a prediction program. BACKGROUND

[0002] In order to realize an automatic driving function and a safety function in a moving body, there is a demand for estimating the electric power supply performance of an electric power storage element mounted on a vehicle or the like.

[0003] The battery control device disclosed in Patent Literature 1 calculates the electric power that can be charged and discharged of a storage battery by simulating the charge and discharge behavior of the storage battery by regarding the storage battery as an electrically equivalent circuit.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2015-114135 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In a case where an electric power storage element model such as an equivalent circuit is used to predict the charge and discharge behavior of the electric power storage element when energized in a prescribed energization pattern, the following operation is performed: the energization pattern is divided by a prescribed unit time, and the voltage at each prescribed time is found. By lengthening the unit time by which the energization pattern is divided, the number of calculations can be reduced, and the prediction time can be shortened, but on the other hand, the prediction accuracy deteriorates. A technique that can balance the shortening of the prediction time and the improvement of the prediction accuracy is desired.

[0009] An object of the present disclosure is to provide a technique that can balance the shortening of the prediction time and the improvement of the prediction accuracy.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] A prediction device according to one embodiment of the present disclosure includes a first prediction unit that predicts a voltage behavior of an electric power storage element when energized in a prescribed energization pattern using an electric power storage element model, and a second prediction unit that predicts a charge and discharge performance of the electric power storage element based on the voltage behavior predicted by the first prediction unit, the first prediction unit predicting the voltage behavior for each interval in which the energization pattern is divided by a time width, the first prediction unit stopping the prediction of the voltage behavior in an interval in which the amount of change in current in the energization pattern is less than a threshold value.

[0012] EFFECT OF THE INVENTION

[0013] According to the present disclosure, the shortening of the prediction time and the improvement of the prediction accuracy can be balanced. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a diagram showing an example of a discharge pattern.

[0015] Figure 2 is a diagram showing an example of discharge pattern data corresponding to the discharge pattern of Figure 1

[0016] Figure 3 is a diagram showing an example of a structure of a power storage device.

[0017] Figure 4 is an exploded perspective view of the power storage device.

[0018] Figure 5 is a block diagram showing an example of a structure of a power storage device provided with a prediction device.

[0019] Figure 6 is a circuit diagram showing an example of a power storage element model.

[0020] Figure 7 is a diagram showing an example of an adjusted discharge pattern.

[0021] Figure 8 is a diagram showing an example of adjusted discharge pattern data corresponding to the discharge pattern of Figure 7

[0022] is a flowchart showing an example of an adjustment process of a conduction pattern performed by a prediction device. Figure 9

[0023] is a flowchart showing an example of a prediction process of a possibility of conduction performed by a prediction device. Figure 10 DETAILED DESCRIPTION

[0024] (1) A prediction device according to an embodiment of the present disclosure includes a first prediction unit configured to predict a voltage behavior of a power storage element when the power storage element is subjected to conduction in a prescribed conduction pattern using a power storage element model, and a second prediction unit configured to predict a charge-discharge performance of the power storage element based on the voltage behavior predicted by the first prediction unit. The first prediction unit predicts the voltage behavior for each section in which the conduction pattern is divided in a time width, and the first prediction unit stops the prediction of the voltage behavior in a section in which a variation amount of a current in the conduction pattern is less than a threshold value. In other words, the first prediction unit does not predict the voltage behavior in a middle section of a plurality of sections in which the variation amount of the current in the conduction pattern is less than the threshold value, which are continuous in time.

[0025] Here, the power storage element can be a power storage cell or a power storage unit including a plurality of power storage cells. ​​

[0026] The energization pattern can also be, for example, a current pattern based on a current value and an energization time.

[0027] For a storage element mounted on a mobile body, in order to reliably operate automatic driving functions and safety functions, it is required to be able to always exert a prescribed charge capacity or discharge capacity. For example, it is required to exert a prescribed discharge capacity to an electrical load connected to the storage element whenever discharge is requested. It is required that a prediction device predicts whether or not energization based on a prescribed energization pattern can be performed with a preset calculation period.

[0028] The prediction device calculates a predicted voltage value of the storage element when energization is performed with the prescribed energization pattern using a storage element model, and predicts whether or not discharge can be performed based on the calculated predicted voltage value. In the calculation of the predicted voltage value, the energization pattern is divided into division times having a time width, and the predicted voltage value is calculated sequentially for each interval.

[0029] Figure 1 is a graph showing an example of a discharge pattern, Figure 2 is a graph showing a discharge pattern corresponding to Figure 1 the discharge pattern of Figure 1 The vertical axis of the graph shown in Figure 1 and Figure 2 is current (unit: ampere (A)), and the horizontal axis is elapsed time (unit: second (s)). In Figure 1 and Figure 2 , the positive side of the current is charge power, and the negative side is discharge power.

[0030] In the black square and the discharge pattern shown by the solid line in Figure 1 , the current value at the start time point (0 seconds) is set to zero, the discharge current value (absolute value of the current value) gradually increases from 0 seconds to 0.15 seconds, the discharge current value gradually decreases from 0.15 seconds to 0.3 seconds, the current value is constant from 0.3 seconds to 0.65 seconds, the discharge current value gradually increases from 0.65 seconds to 0.75 seconds, and the discharge current value gradually decreases from 0.75 seconds to the end time point (1 second).

[0031] By recording the current value in the discharge pattern at every prescribed division time, the discharge pattern data of Figure 2 is obtained. In the examples of Figure 1 and Figure 2 , the division time is 0.05 seconds.

[0032] In the storage element model, the voltage value after energization is predicted in the case where a certain current value is energized for a prescribed time. In the calculation of the predicted voltage using the storage element model, the voltage value within each division time is recognized as constant. In Figure 1In this case, the white circle and the dotted line indicate the recognition pattern at the time of calculation recognized on the basis of the discharge pattern.

[0033] The discharge current value from 0 seconds to 0.05 seconds gradually increases from 0 A to 100 A in the actual discharge pattern, but is recognized as constant 100 A at the time of calculation. Due to the deviation of the recognition of the current value, the consumed capacity of the discharge pattern deviates from the consumed capacity at the time of calculation. The deviation of the consumed capacity becomes a cause of the deterioration of the prediction accuracy of the predicted voltage value of the storage element model. In the case where the interval including the current change is included in the energization pattern, the prediction accuracy of the predicted voltage value deteriorates. Regarding the deterioration of the prediction accuracy caused by the energization pattern accompanied by the current change, the longer the total energization time of the energization pattern, the greater the deviation of the consumed capacity, and thus the greater the degree thereof.

[0034] In order to improve the prediction accuracy of the energization pattern accompanied by the current change, it is preferable to shorten the division time, but if the division time is shortened, the number of calculations increases, and thus the calculation cost increases, and the prediction time becomes longer. In the case where the energization pattern to be the prediction object is plural, it is necessary to perform the prediction for each energization pattern, and the load further increases.

[0035] If the number of calculations increases, there is a concern that the prediction at all time points cannot be completed in the allowable time allowed for the prediction processing of the discharge possibility within a certain calculation cycle. In order to complete the prediction within the allowable time, it is considered to shorten the calculation cycle or to extend the division time of the discharge pattern to reduce the number of calculations. Shortening the calculation cycle increases the load of the prediction device, and thus is not preferable, and there is also a limitation from the viewpoint of performance. If the division time is extended, the original energization pattern cannot be properly reflected, and the prediction accuracy deteriorates. For example, in the case where the division time of the discharge pattern shown in FIG. 7 is set to 0.1 seconds, as the discharge pattern data, 0.1 seconds-200 A is followed by 0.2 seconds-250 A, and -300 A at 0.3 seconds is not reflected. In the case where the division time is 0.1 seconds, the minimum value of the predicted voltage value is higher than that in the case where the division time is 0.05 seconds, and the prediction accuracy of the discharge possibility deteriorates. Figure 1

[0036] ​The prediction device according to (1) described above can reduce the number of calculation processes as a whole by not performing the calculation process for voltage prediction in the middle interval of the period in which the amount of change in current in the energization pattern is less than the threshold value. By shortening the division time, it is possible to shorten the prediction time while improving the prediction accuracy. The prediction device can also connect a plurality of intervals that are continuous in time in which the amount of change in current is less than the threshold value to one new interval, and thereby predict the voltage behavior across the plurality of continuous intervals by one calculation process. By limiting the reduction in the number of calculation processes to the period in which the amount of change in current is less than the threshold value, it is possible to suppress deterioration in prediction accuracy and efficiently perform the operation. Based on the thus-predicted voltage behavior, it is possible to efficiently and accurately predict the charge-discharge performance.

[0037] (2) In the prediction device according to (1) described above, the energization pattern can include an interval in which the current is constant.

[0038] The prediction device according to (2) described above can achieve an improvement in prediction accuracy and a reduction in operation load with respect to the energization pattern including the interval in which the current is constant.

[0039] (3) In the prediction device according to (1) or (2) described above, the first prediction unit can adjust the energization pattern based on the current at the switching point at which the increase or decrease direction of the current is switched in the interval in which the amount of change in current in the energization pattern is equal to or greater than the threshold value, and predict the voltage behavior based on the adjusted energization pattern.

[0040] The prediction device according to (3) described above can adjust the current value of the energization pattern in consideration of the consumption capacity in the energization pattern. By adjusting the energization pattern, it is possible to eliminate the deviation of the energization pattern from the recognized consumption capacity at the time of calculation. In addition, the current value of the energization pattern can be adjusted in consideration of the current at the switching point at which the increase or decrease direction of the current is switched. Since it is possible to reflect the maximum value or the minimum value of the current in the adjustment of the energization pattern, it is possible to suppress the prediction of the minimum voltage value to be higher than the actual value or the prediction of the maximum voltage value to be lower than the actual value. The prediction accuracy with respect to the energization pattern including the interval in which the current changes is improved.

[0041] (4) In the prediction device according to (3) described above, the interval in which the amount of change in current in the energization pattern is equal to or greater than the threshold value can include an interval in which the increase or decrease direction of the current is switched and an interval in which the increase or decrease direction of the current is not switched, and the first prediction unit can adjust the energization pattern based on the current at the switching point in the interval in which the increase or decrease direction of the current is switched and the consumption capacity in the interval in which the increase or decrease direction of the current is not switched.

[0042] The prediction device according to (4) described above, in an interval in which the increasing / decreasing direction of the current is not switched, eliminates the deviation of the consumption capacity by using the power value corresponding to the consumption capacity. In addition, in an interval in which the increasing / decreasing direction of the current is switched, by using the actual current value instead of the adjustment that takes the consumption capacity into account, the minimum or maximum of the predicted voltage value can be predicted with high precision.

[0043] (5) In the prediction device according to any one of (1) to (4) described above, the energization pattern can include an interval in which the amount of change in the current in the energization pattern is less than a prescribed value and an interval in which the amount of change in the current is the prescribed value or more.

[0044] The prediction device according to (5) described above can achieve an improvement in prediction accuracy and a reduction in computational load with respect to an energization pattern that includes a period in which the current hardly changes and a period in which the current changes. With respect to a variety of energization patterns, the charge / discharge performance can be determined efficiently and with high precision.

[0045] (6) In the prediction device according to any one of (1) to (5) described above, an output section that outputs the charge / discharge performance of the power storage element predicted by the second prediction section to an external device can be provided.

[0046] The prediction device according to (6) described above can reliably report the determined charge / discharge performance to an external device.

[0047] (7) A power storage device according to an embodiment of the present disclosure includes a power storage element and the prediction device according to any one of (1) to (6) described above.

[0048] (8) A prediction method according to an embodiment of the present disclosure predicts a voltage behavior of a power storage element when the power storage element is energized in a prescribed energization pattern using a power storage element model, predicts a charge / discharge performance of the power storage element based on the predicted voltage behavior, predicts the voltage behavior for each interval in which the energization pattern is divided in a time axis direction, and stops the prediction of the voltage behavior in an interval in which the amount of change in the current in the energization pattern is less than a threshold value.

[0049] (9) A prediction program according to an embodiment of the present disclosure causes a computer to perform the following processing: predicting a voltage behavior of a power storage element when the power storage element is energized in a prescribed energization pattern using a power storage element model, predicting a charge / discharge performance of the power storage element based on the predicted voltage behavior, predicting the voltage behavior for each interval in which the energization pattern is divided in a time axis direction, and stopping the prediction of the voltage behavior in an interval in which the amount of change in the current in the energization pattern is less than a threshold value.

[0050] (10) A prediction device according to an aspect of the present disclosure includes: a first prediction unit configured to predict a voltage behavior of an electrical storage element when the electrical storage element is energized in a prescribed energization pattern using an electrical storage element model; and a prediction unit configured to predict a charge-discharge performance of the electrical storage element based on the voltage behavior predicted by the first prediction unit, the first prediction unit dividing the energization pattern into a plurality of periods and predicting the voltage behavior for each of the periods, a period in which a variation in current in the energization pattern is less than a threshold value having a longer time width than a period in which the variation in current in the energization pattern is equal to or greater than a prescribed value.

[0051] According to the prediction device of (10) described above, the length of the time width in which the voltage behavior is predicted can be changed depending on whether or not the current varies in the energization pattern. The deterioration of the prediction accuracy can be suppressed, and the calculation efficiency can be improved.

[0052] The present disclosure will be specifically described with reference to the drawings illustrating an embodiment of the present disclosure.

[0053] (First Embodiment)

[0054] Figure 3 is a perspective view showing a structure example of an electrical storage device 1, Figure 4 is an exploded perspective view of the electrical storage device 1. Hereinafter, the structure example of the electrical storage device 1 will be described while referring to each direction of "front and back", "left and right", and "up and down" shown in the drawings.

[0055] The electrical storage device 1 is, for example, a battery suitable for mounting on an engine vehicle, an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or the like. The electrical storage device 1 is, for example, a 12-volt (V) battery or a 48V battery.

[0056] The electrical storage device 1 includes a plurality of electrical storage battery cells 2, a prediction device 3, and a busbar unit 4. The electrical storage device 1 is an example of an electrical storage element. The electrical storage battery cells 2, the prediction device 3, and the busbar unit 4 are housed inside a housing case 10. The electrical storage battery cells 2 are, for example, battery cells based on lithium-ion secondary batteries.

[0057] In the embodiment, the electrical storage element is an electrical storage unit having a plurality of electrical storage battery cells 2. Alternatively, the electrical storage element can be a single electrical storage battery cell 2.

[0058] The prediction device 3 is, for example, a battery management system (BMS). The prediction device 3 performs a charge-discharge possibility prediction of predicting whether or not the electrical storage device 1 satisfies a prescribed charge-discharge performance, that is, a charge-discharge performance of the electrical storage device 1.

[0059] In the embodiment, the prediction device 3 is mounted inside the power storage device 1. Alternatively, the prediction device 3 can be provided separately from the power storage device 1. The prediction device 3 can also be a server device, a terminal device, or a computer such as a vehicle ECU connected to the outside of the power storage device 1. In this case, measured data measured with respect to the power storage device 1 can be transmitted to the server device or the like through communication.

[0060] The housing case 10 is made of synthetic resin. The housing case 10 includes a case main body 11 having an upper surface opening and a cover 12 covering the opening of the case main body 11. The case main body 11 and the cover 12 are fixed in a liquid-tight manner by fasteners such as screws, an adhesive, or welding in a state in which the power storage battery cell 2, the prediction device 3, and the bus bar unit 4 are housed. A pair of external terminals 13A and 13B having different polarities are provided on one side surface of the housing case 10.

[0061] The power storage battery cell 2 includes a hollow rectangular case 21. A positive terminal 22 and a negative terminal 23 of the power storage battery cell 2 are provided on an upper surface of the case 21. An electrode body and an electrolyte solution, which are not shown, are housed in the inside of the case 21.

[0062] The electrode body is configured by overlapping a sheet-shaped positive electrode and a sheet-shaped negative electrode via two sheet-shaped separators and winding them (longitudinal winding or transverse winding). The separator is formed of a porous resin film. As the porous resin film, a porous resin film composed of a resin such as polyethylene (PE) or polypropylene (PP) can be used.

[0063] The positive electrode is an electrode plate in which a positive electrode active material layer is formed on the surface of a long strip-shaped positive electrode substrate composed of, for example, aluminum, an aluminum alloy, or the like. The positive electrode active material layer contains a positive electrode active material. As the positive electrode active material used in the positive electrode active material layer, a material capable of occluding and releasing lithium ions can be used. As the positive electrode active material, for example, LiFeP04 can be cited. The positive electrode active material layer can further contain a conductive aid, a binder, or the like.

[0064] The negative electrode is an electrode plate in which a negative electrode active material layer is formed on the surface of a long strip-shaped negative electrode substrate composed of, for example, copper or a copper alloy, or the like. The negative electrode active material layer contains a negative electrode active material. The negative electrode active material can use a material capable of occluding and releasing lithium ions. As the negative electrode active material, for example, graphite, hard carbon, soft carbon, or the like can be cited. The negative electrode active material layer can further contain a binder, a thickening agent, or the like.

[0065] The electrolyte can be the same as that used in conventional lithium-ion secondary batteries. For example, an electrolyte containing a supporting salt in an organic solvent can be used. Examples of organic solvents include aprotic solvents such as carbonates, esters, and ethers. Lithium salts such as LiPF6, LiBF4, and LiClO4 are preferably used as the supporting salt. The electrolyte may also contain various additives such as gas generators, film-forming agents, dispersants, and thickeners.

[0066] In this embodiment, the battery cell 2 is a battery cell based on a lithium-ion secondary battery. Alternatively, the battery cell 2 can be a battery cell based on all-solid-state batteries, lead-acid batteries, redox flow batteries, zinc-air batteries, alkaline manganese batteries, lithium-sulfur batteries, sodium-sulfur batteries, silver-zinc oxide batteries, nickel-metal hydride batteries, molten salt thermal batteries, etc., or it can be a capacitor.

[0067] In this embodiment, the battery cell 2 is a square battery cell with wound electrodes. Alternatively, the battery cell 2 can be a cylindrical battery cell, a laminated type (pouch type) battery cell, or a battery cell with stacked electrodes.

[0068] In this embodiment, the number of battery cells 2 housed in the housing body 11 is four. Alternatively, the number of battery cells 2 housed in the housing body 11 may be one or more but less than four, or may be more than four. In the following description, the battery cells 2 will also be referred to sequentially from the front side of the housing body 11 as first battery cell 2A, second battery cell 2B, third battery cell 2C, and fourth battery cell 2D.

[0069] like Figure 4 As shown, each battery cell 2 is housed in the housing body 11 with the positive terminals 22 and negative terminals 23 of adjacent battery cells 2 facing opposite directions.

[0070] A prediction device 3 is disposed on the terminal surface of the battery cell 2 via a bus unit 4. The bus unit 4 includes multiple buses 41 and a resin bus frame 42 that holds these buses 41. Each bus 41 is connected to the lower surface of the prediction device 3 by fasteners 43 such as screws. The battery cell 2 and the prediction device 3 are connected via the bus 41.

[0071] The bus bars 41 constitute charge / discharge paths for the storage battery cells 2. The bus bars 41 are made of metal and formed of a material having excellent electrical conductivity and high thermal conductivity, such as aluminum, aluminum alloy, copper, copper alloy, stainless steel, or the like. In adjacent storage battery cells 2, the positive terminal 22 of one of the storage battery cells 2 and the negative terminal 23 of the other storage battery cell 2 are electrically connected by the bus bar 41. Further, the negative terminal 23 of the first storage battery cell 2A and one of the external terminals 13A are connected by the bus bar 41, and the positive terminal 22 of the fourth storage battery cell 2D and the other external terminal 13B are connected by the bus bar 41.

[0072] In Figure 3 and Figure 4 , a structure in which four storage battery cells 2 are connected in series by bus bars 41 is described. Instead, some or all of the storage battery cells 2 can be connected in parallel.

[0073] The prediction device 3 is provided with a flat circuit board 61. On the upper surface of the circuit board 61, a cutoff circuit 62, a temperature sensor 63, a current sensor 64, and a voltage sensor 65 (see Figure 5 ), and the like are mounted. The prediction device 3 can also be configured as a circuit board unit in which the cutoff circuit 62, the temperature sensor 63, the current sensor 64, and the voltage sensor 65 are mounted on the circuit board 61.

[0074] The cutoff circuit 62 is a circuit for connecting or cutting off the conductive path between the bus bar 41 connected to the positive terminal 22 of the fourth storage battery cell 2D and the bus bar 66 connected to the external terminal 13B. The cutoff circuit 62 is configured, for example, by a semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). By switching the cutoff circuit 62 from an on state to an off state, the outflow of current from the storage battery cells 2 to the outside and the inflow of current from the outside to the storage battery cells 2 can be cut off. Instead, the cutoff circuit 62 can also be configured by a relay switch.

[0075] The temperature sensor 63 is, for example, a thermistor, a thermocouple, or the like. The temperature sensor 63 measures the temperature associated with the power storage device 1. In Figure 4In this case, the temperature sensor 63 is disposed at a position sufficiently away from the electrically energized heat generating body (for example, the cut-off circuit 62, the bus bars 41, 66, the fastener 43, and the like) on the circuit board 61. The temperature data measured by the temperature sensor 63 represents the ambient temperature of the power storage device 1 (the temperature of the surroundings of the power storage cells 2). The power storage element can further be provided with a temperature sensor 63 that is disposed in the vicinity of the electrically energized heat generating body on the circuit board 61 and measures the temperature of the electrically energized heat generating body on the circuit board 61. In this case, the temperature of the power storage device 1 can also be determined based on the ambient temperature of the power storage device 1 and the temperature of the electrically energized heat generating body on the circuit board 61.

[0076] Figure 5 is a block diagram that represents a configuration example of the power storage device 1 provided with the prediction device 3. The power storage device 1 is connected to a vehicle ECU (Electronic Control Unit) 71, an electrical load 72 such as an electrical component, and an alternator not shown via external terminals 13A, 13B.

[0077] In the case where the vehicle is an engine vehicle, in the driving of the engine, in the case where the power generation amount of the alternator is larger than the power consumption amount of the electrical load 72, the power storage device 1 is charged by the alternator. In the case where the power generation amount of the alternator is smaller than the power consumption amount of the electrical load 72, the power storage device 1 is discharged in order to make up for the deficient amount. In the parking of the vehicle, the alternator stops power generation, and thus the power storage device 1 becomes a state of not being charged and a state of being discharged only to the vehicle ECU 71 and the electrical load 72.

[0078] In the case where the vehicle is a vehicle that is able to start running by a high-voltage system (a driving power storage device) instead of an internal combustion engine, the power storage device 1 supplies power for being able to start the high-voltage system. In the parking of the vehicle, the power storage device 1 discharges to the vehicle ECU 71 and the electrical load 72, and is able to perform charging based on the high-voltage system.

[0079] The vehicle ECU 71 is a vehicle control section that controls the vehicle. The vehicle ECU 71 controls the electrical load 72. The vehicle ECU 71 controls the charge or discharge amount of the power storage device 1 by controlling the electrical load 72 based on the prediction result of the possibility of charge and discharge accepted from the prediction device 3. The vehicle ECU 71 is an example of a higher-level device.

[0080] The prediction device 3 is a computer provided with a control section 31, a storage section 32, an input / output section 33, a communication section 34, and the like. In the present embodiment, the prediction device 3 is realized by a circuit board, but as an alternative, the prediction device 3 can also be a structure in which a plurality of computers are constituted and distributed processing is performed, can also be realized by a plurality of virtual machines provided in one server, and can also be realized using a cloud server.

[0081] The control section 31 is an arithmetic circuit including a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU or the GPU included in the control section 31 executes various computer programs stored in the ROM, the storage section 32, and the like, and controls the operation of each of the above-described hardware sections. The control section 31 can also include a function of a timer that measures the elapsed time from the time when a measurement start instruction is given until the time when a measurement end instruction is given, a counter that counts the number, a clock that outputs date and time information, and the like.

[0082] The storage section 32 includes a nonvolatile storage device such as a flash memory, a hard disk drive, and the like. The storage section 32 stores various computer programs and data, and the like, which are referred to by the control section 31. The storage section 32 can also be an external storage device connected to the prediction device 3.

[0083] The storage section 32 of the present embodiment stores a prediction program 321 for causing a computer to execute processing related to the prediction of the possibility of charge and discharge, and a prediction data 322 that is data required for the execution of the prediction program 321. The prediction data 322 includes a storage battery element model used in simulation. The storage battery element model is described by structure information representing the circuit structure, values of each element that constitutes the storage battery element model, and the like. The structure information representing the circuit structure of the storage battery element model, the values of each element that constitutes the storage battery element model, and the like are stored in the storage section 32.

[0084] The computer program (computer program product) including the prediction program 321 can also be provided by a non-transitory recording medium 3A in which the computer program is recorded in a readable manner. The recording medium 3A is, for example, a magnetic disk, an optical disk, a semiconductor memory, or the like. The control section 31 reads the desired computer program from the recording medium 3A using a not-illustrated reading device, and causes the read computer program to be stored in the storage section 32. Alternatively, the above-described computer program can also be provided through communication. The prediction program 321 can be constituted by a single computer program, or can be constituted by a plurality of computer programs, and furthermore, can be executed on a single computer, or can be executed on a plurality of computers connected to each other through a communication network.

[0085] The input and output section 33 includes an input and output interface for connecting external devices. The input and output section 33 is connected to the cut-off circuit 62, the temperature sensor 63, the current sensor 64, the voltage sensor 65, and the like.

[0086] The control section 31 outputs a control signal to the cutoff circuit 62 through the input / output section 33, thereby switching the on state and the off state of the cutoff circuit 62. In addition, the control section 31 acquires data of the temperature measured by the temperature sensor 63, data of the current measured by the current sensor 64, and data of the voltage measured by the voltage sensor 65 at all times through the input / output section 33.

[0087] The current sensor 64 is, for example, a shunt resistor connected in series to the storage battery cell 2. The current sensor 64 measures the current flowing through the storage battery cell 2 in time series based on the voltage across the storage battery cell 2. The polarity (positive or negative) of the voltage across can be used to distinguish between discharge and charge. Alternatively, the current sensor 64 can be a magnetic sensor.

[0088] The voltage sensor 65 is connected in parallel to each storage battery cell 2. The voltage sensor 65 is connected across each storage battery cell 2, respectively, and measures the voltage across each storage battery cell 2 in time series. The control section 31 acquires data of the voltage of each storage battery cell 2 measured by the voltage sensor 65 and the total voltage of the power storage device 1 through the input / output section 33.

[0089] The input / output section 33 can be connected to a display device such as a liquid crystal display device. The control section 31 can output the estimation result of the usable SOC range via the input / output section 33 and display it on the display device.

[0090] The communication section 34 has a communication interface that enables communication with the vehicle ECU 71 or other external devices. The control section 31 transmits and receives various data including the prediction result of the ability or inability to charge and discharge between the vehicle ECU 71 or other external devices through the communication section 34.

[0091] Figure 6 is a circuit diagram showing an example of a storage battery cell model. The storage battery cell model is used for the prediction of the voltage behavior of the power storage device 1.

[0092] Figure 6 The storage battery cell model shown in FIG. 8 is an equivalent circuit model that is a combination of a voltage source of the storage battery cell 2 and circuit elements such as a resistor, a capacitor, and the like, and simulates the charge and discharge behavior of the storage battery cell 2. The equivalent circuit model has, for example, a constant voltage source, a direct current resistor, and an RC parallel circuit connected in series between the positive and negative terminals. In the equivalent circuit model, the constant voltage source is connected in series to the direct current resistor, and the RC parallel circuit is connected in parallel to the direct current resistor. Figure 6 In the equivalent circuit model, two RC parallel circuits, a first RC parallel circuit and a second RC parallel circuit, are connected in series, but the RC parallel circuit is not limited to two stages.

[0093] The constant voltage source is a voltage source that outputs a direct current voltage. The voltage output by the constant voltage source is the open circuit voltage (OCV) of the storage battery cell 2, which is denoted as VOCV The open-circuit voltage V OCV is given, for example, as a function of the SOC. The open-circuit voltage V OCV may also be given as a function of the actual capacity of the storage battery cell 2.

[0094] The DC resistor is used to describe the DC resistance component (DC impedance) of the storage battery cell 2, including the resistance element R0. The value of the resistance element R0 is given as a value that varies depending on the current, the voltage, the SOC, the temperature, and the like. If the value of the resistance element R0 is determined, the voltage generated in the DC resistor when the current I flows through the equivalent circuit model can be calculated. The voltage generated in the DC resistor is set as the DC resistance voltage V R0 .

[0095] The two RC parallel circuits are circuit elements used to describe the polarization characteristics of the transient of the storage battery cell 2. The first RC parallel circuit is composed of the resistance element R1 and the capacitance element C1 connected in parallel. The second RC parallel circuit is composed of the resistance element R2 and the capacitance element C2 connected in parallel. The values of the resistance elements R1, R2 and the capacitance elements C1, C2 are given as values that vary depending on the current, the SOC, the temperature, and the like. The impedances of the first RC parallel circuit and the second RC parallel circuit are determined from the resistance elements R1, R2 and the capacitance elements C1, C2. If the impedances of the first RC parallel circuit and the second RC parallel circuit are determined, the voltage (polarization voltage) generated in the first RC parallel circuit and the second RC parallel circuit when the current I flows through the equivalent circuit model can be calculated. The polarization voltage is the total voltage of the polarization voltage V1 generated in the first RC parallel circuit and the polarization voltage V2 generated in the second RC parallel circuit.

[0096] In the above equivalent circuit model, the terminal voltage (predicted voltage value) V cell of the storage battery cell 2 between the positive terminal and the negative terminal at the time point t seconds later can be calculated using the current I, the open-circuit voltage V OCV , the polarization voltage V1, the polarization voltage V2, the resistance elements R0, R1, R2, and the capacitance elements C1, C2, by the following equation (1).

[0097] [Mathematical equation 1]

[0098]

[0099] The values of the resistance elements R0, R1, R2 and the capacitance elements C1, C2 used in the equivalent circuit model can be obtained in advance on the basis of measured data or the like.

[0100] By calculating the predicted voltage value V cellThe total value is used to calculate the predicted voltage value of the energy storage device 1. The predicted voltage value of the energy storage device 1 can also be set as a value that takes into account the voltage caused by the resistive components of the conductive parts in the energy storage device 1 (e.g., busbars 41, 66, disconnect circuit 62, etc.).

[0101] The prediction method for whether the energy storage element model can be charged and discharged, which is executed by the prediction device 3, using the above-mentioned energy storage element model, will be explained below. Hereinafter, the prediction method for whether the energy storage element can be charged and discharged will be explained with the following example: the power supply mode is the discharge mode, and the prediction is whether the specified power can be supplied (SOF: State of Function).

[0102] When predicting whether charging and discharging are possible, the prediction device 3 acquires information about the discharge mode being predicted. This discharge mode information is specified, for example, from a higher-level device. The discharge mode information may also include the current value, duration, and operating voltage range associated with the discharge mode. The current value and duration are given, for example, in the form of discharge mode data. The discharge mode data may also be data that divides the discharge mode into time widths corresponding to a predetermined time interval, and correlates the time (elapsed time from the start time) corresponding to each interval with the current value at that time. The operating voltage range is the lower limit voltage of the energy storage device 1 during discharge and the upper limit voltage of the energy storage device 1 during charging. As an example, suppose the aforementioned... Figure 5 and Figure 6 The discharge mode is the target for prediction.

[0103] The prediction device 3 uses the aforementioned energy storage element model to calculate the predicted voltage value when discharging in a specified discharge mode. In this embodiment, the prediction device 3 adjusts the discharge mode obtained from the host device to be suitable for prediction processing, and predicts the voltage value based on the adjusted discharge mode. The prediction device 3 reduces the number of calculations during the current-constant period of the discharge mode. Furthermore, it adjusts the current value during the current-changing period of the discharge mode.

[0104] Figure 7 This is a diagram illustrating an example of the adjusted discharge mode. Figure 8 It means and Figure 7 A figure showing an example of the adjusted discharge mode data corresponding to the discharge mode. Figure 7 The graph shown has the following dimensions: vertical axis represents current (in amperes) and horizontal axis represents elapsed time (in seconds). Figure 7 In the diagram, black squares and solid lines represent the discharge mode before adjustment, while white circles and dashed lines represent the discharge mode after adjustment and the recognition mode during calculation based on the discharge mode.

[0105] The prediction device 3 calculates the difference between the current values that are continuous in time based on the discharge pattern data before adjustment, and thereby obtains the amount of change in current in each section. In the discharge pattern data before adjustment, as shown in FIG. 7, the current value is recorded every time that is divided by a certain division time. The prediction device 3 classifies the entire section of the discharge pattern data into a section in which the amount of change in current is not zero and a section in which the amount of change in current is zero based on the calculation result. In the discharge pattern of the present embodiment, the sections from 0 seconds to 0.15 seconds and from 0.65 seconds to 0.75 seconds are sections in which the amount of change in current is not zero, and the section from 0.3 seconds to 0.65 seconds is a section in which the amount of change in current is zero. Figure 6

[0106] In a case where the discharge pattern data includes a constant current period in which a plurality of sections that are continuous in time and in which the amount of change in current is zero, the prediction device 3 omits the data of the middle section of the constant current period from the discharge pattern data. In the constant current period, the plurality of sections included in the current change period are regarded as one integral section, and the prediction calculation of the storage element model is performed only once for the one integral section.

[0107] Figure 7 Figure 8 As shown in FIG. 7, the section from 0.3 seconds to 0.65 seconds is a constant current period, and therefore the data of the middle time from 0.35 seconds to 0.6 seconds is removed. In the prediction calculation, the calculation of the middle time (middle section) is omitted, and the predicted voltage value in a case where the constant current value in the current change period is applied is obtained across the integrated time that is integrated by adding the division times of the plurality of sections.

[0108] In the above, the section in which the amount of change in current value is zero is obtained, but the section in which the amount of change in current value is smaller than a threshold value can also be regarded as a constant current section.

[0109] Further, in a case where the discharge pattern data includes a current change period in which a section in which the amount of change in current is not zero is included, the prediction device 3 adjusts the current value of the discharge pattern. The prediction device 3 classifies each section included in the current change period into a section in which the increasing / decreasing direction of current is not switched and a section in which the increasing / decreasing direction of current is switched.

[0110] In the section in which the increasing / decreasing direction of current is not switched, the consumed capacity of the discharge pattern in the section is calculated, and the current value of the discharge pattern is adjusted in a manner corresponding to the calculated consumed capacity. The prediction device 3 obtains the adjusted current value in a manner such that the consumed capacity in a case where discharge is performed with a constant current value across the division time is equal to the consumed capacity of the discharge pattern.

[0111] ​​​In the section in which the increasing and decreasing directions of the current are switched, the current value of the discharge mode corresponding to the switching point at which the increasing and decreasing directions of the current are switched is directly used as the adjustment current value. In Figure 7 and Figure 8 In the example shown in FIG. 8, 0.15 seconds and 0.75 seconds correspond to the switching points, and thus in the sections of 0.15 to 0.2 seconds and 0.75 to 0.8 seconds, the current values corresponding to the respective switching points are directly applied. The adjustment of the current value is performed for each section included in the current variation period. Through the above-described processing, the discharge mode data in which the number of data points is reduced and the current value is adjusted is generated, as shown in FIG. 9. Figure 8

[0112] The prediction device 3 predicts whether or not discharge based on the discharge mode is possible at a predetermined calculation cycle based on the obtained adjusted discharge mode.

[0113] The prediction device 3 calculates the predicted voltage value of the power storage device 1 when discharge is performed with the adjusted discharge mode using the power storage element model. The predicted voltage value is calculated for each section of the adjusted discharge mode. The prediction device 3 predicts whether or not discharge is possible based on the calculated predicted voltage value. Whether or not discharge is possible is predicted by determining whether or not the predicted voltage value is equal to or higher than a lower limit voltage set in advance. In the entire period involved in the discharge mode, it is determined that discharge is possible when the predicted voltage value is equal to or higher than the lower limit voltage. It is determined that discharge is impossible when the predicted voltage value is lower than the lower limit voltage.

[0114] The above-described case in which the energization mode is the discharge mode is described as an example. In the case in which the energization mode is the charge mode, the charge mode can also be adjusted by applying the above-described method. Whether or not charge is possible can be predicted by determining whether or not the predicted voltage value when charge is performed with the adjusted charge mode is equal to or lower than an upper limit voltage set in advance.

[0115] Figure 9 FIG. 10 is a flowchart showing an example of the processing procedure of the adjustment of the energization mode performed by the prediction device 3. The processing in the flowchart below is performed by the control section 31 in accordance with the prediction program 321 stored in the storage section 32 of the prediction device 3.

[0116] The control section 31 of the prediction device 3 acquires the energization mode data (step S11). The energization mode data is transmitted from a higher-level device (for example, the vehicle ECU 71), for example.

[0117] The control section 31 calculates the current variation amount of each section based on the acquired energization mode data, thereby classifying the entire section of the energization mode data into a section in which the current variation amount is not zero and a section in which the current variation amount is zero (step S12).

[0118] ​The control section 31 determines whether the energization pattern data contains a current constant period based on the classification result (step S13). In a case where it is determined that the energization pattern data does not contain a current constant period (S13: No (NO)), the control section 31 causes the process to proceed to step S15.

[0119] In a case where it is determined that the energization pattern data contains a current constant period (S13: Yes (YES)), the control section 31 omits data of an interval in the middle of the current constant period from the energization pattern data (step S14).

[0120] The control section 31 determines whether the energization pattern data contains a current change period based on the classification result (step S15). In a case where it is determined that the energization pattern data does not contain a current change period (S15: No (NO)), the control section 31 ends the process.

[0121] In a case where it is determined that the energization pattern data contains a current change period (S15: Yes (YES)), the control section 31 determines whether an interval contained in the current change period is an interval in which the increasing / decreasing direction of the current is switched (step S16).

[0122] In a case where it is determined that it is not an interval in which the increasing / decreasing direction of the current is switched, that is, an interval in which the increasing / decreasing direction of the current is not switched (S16: No (NO)), the control section 31 calculates an adjustment current value for adjusting the discharge pattern data based on the consumption capacity in the interval (step S17). The control section 31 calculates the consumption capacity of the discharge pattern in such a manner that the calculated consumption capacity is equal to the consumption capacity in a case where discharge is performed with the adjustment current value across the divided time, and obtains the adjustment current value.

[0123] In a case where it is determined that it is an interval in which the increasing / decreasing direction of the current is switched (S16: Yes (YES)), the control section 31 determines the adjustment current value based on the current value of the energization pattern corresponding to the switching point of the increasing / decreasing direction (step S18). The control section 31 uses the current value of the switching point as the adjustment current value. The control section 31 performs the process of steps S16 to S18 for each interval contained in the current change period. The control section 31 stores the discharge pattern defined by the number of data points after omission and the adjustment current value as the adjusted energization pattern in the storage section 32, and ends the series of processes.

[0124] Figure 10 This is a flowchart showing an example of the prediction process performed by the prediction device 3. The control section 31 of the prediction device 3 repeatedly performs the following process, for example, at a predetermined calculation cycle.

[0125] The control section 31 of the prediction device 3 acquires measurement data including the temperature, the current, and the voltage of the power storage device 1 (step S21).

[0126] The control section 31 predicts, as a function of the first prediction section, a predicted voltage value of the electrical storage device 1 at the time of energization in the adjusted energization pattern based on the acquired measurement data (step S22). The prediction of the predicted voltage value is performed for each interval using the electrical storage element model. The control section 31 calculates the predicted voltage value of the plurality of intervals in conjunction with the current constant period in compliance with the adjusted energization pattern data, thereby omitting the calculation of the interim interval. The control section 31 predicts the predicted voltage value using the adjusted current value in the current variation period.

[0127] The control section 31 predicts, as a function of the second prediction section, whether or not the energization based on the energization pattern is possible based on the predicted predicted voltage value (step S23). Whether or not the energization is predicted by determining whether or not the predicted predicted voltage value is equal to or higher than a lower limit voltage or lower than an upper limit voltage that is set in advance. In a case where the predicted voltage value is equal to or higher than the lower limit voltage or lower than the upper limit voltage, it is predicted that the energization is possible. In a case where the predicted voltage value is not equal to or higher than the lower limit voltage or lower than the upper limit voltage, it is predicted that the energization is not possible.

[0128] The control section 31 outputs, as a function of the output section, information based on the prediction result of whether or not the energization is possible to an external device (for example, the vehicle ECU 71) (step S24), and ends the series of processes.

[0129] The prediction device, the prediction method, and the prediction program can also be applied to uses other than vehicles, for example, can be applied to flying bodies such as airplanes, flying vehicles, HAPS (High Altitude Platform Station), and can be applied to ships, submarines. The electrical storage device 1 can also be a high-voltage battery.

[0130] According to the present embodiment, by adjusting the discharge pattern, it is possible to balance the improvement of the prediction accuracy of the predicted voltage value and the charge / discharge performance and the shortening of the prediction time.

[0131] It should be considered that the embodiments disclosed this time are illustrative in all respects, not restrictive. The technical features described in each of the embodiments can be combined with each other, and the scope of the present application is intended to include all modifications of the claims and the scope equivalent thereto.

[0132] The sequence shown in each of the embodiments is not limited, and each of the processes can be executed by changing the order thereof within a range where there is no contradiction, and in addition, a plurality of processes can be executed in parallel. The processing subject of each of the processes is not limited, and within a range where there is no contradiction, another device can execute the process of each of the devices.

[0133] The matters described in the embodiments can be combined with each other. In addition, the independent claims and the dependent claims described in the claims are not related to the citation form, and can be combined with each other in all total combinations. Further, the form of the claim in which the claim citing other two or more claims is described (the form of the multiple claims) is used in the claims, but is not limited thereto. The form of the multiple claims (the form of the multiple citing multiple claims) in which at least one multiple claim is cited can also be used.

[0134] Explanation of Reference Signs

[0135] 1 storage device (storage element); 2 storage battery cell; 3 prediction device; 31 control section; 32 storage section; 33 input / output section; 34 communication section; 321 prediction program; 322 prediction data; 3A recording medium.

Claims

1. A prediction device comprising: The first prediction unit uses a storage element model to predict the voltage behavior of the storage element when it is energized in a specified energizing mode; and The second prediction unit predicts the charge and discharge performance of the energy storage element based on the voltage behavior predicted by the first prediction unit. The first prediction unit predicts the voltage behavior by dividing the power-on mode into intervals with a time width. The first prediction unit stops predicting the voltage behavior when the change in current in the energized mode is less than a threshold.

2. The prediction device according to claim 1, wherein, The energizing mode includes a range where the current is constant.

3. The prediction device according to claim 1 or claim 2, wherein, The first prediction unit adjusts the power-on mode based on the consumed capacity or the current at the switching point where the direction of current increase or decrease changes in the power-on mode is switched within an interval where the change in current is above a threshold. The first prediction unit predicts the voltage behavior based on the adjusted power-on mode.

4. The prediction device according to claim 3, wherein, The range of current change above the threshold in the power-on mode includes the range where the direction of current increase or decrease switches and the range where the direction of current increase or decrease does not switch. The first prediction unit adjusts the power-on mode based on the current at the switching point in the interval where the direction of current increase or decrease is switched and the consumed capacity in the interval where the direction of current increase or decrease is not switched.

5. The prediction device according to claim 1 or claim 2, wherein, The power-on mode includes the range where the change in current is less than a specified value and the range where the change in current is greater than or equal to a specified value.

6. The prediction device according to claim 1 or claim 2, wherein, It has an output section that outputs the charge and discharge performance of the energy storage element predicted by the second prediction section to an external device.

7. An energy storage device, comprising: Energy storage components; and The prediction device according to claim 1 or claim 2.

8. A prediction method, wherein, The energy storage element model is used to predict the voltage behavior of the energy storage element when it is energized in a specified energizing mode; The charge and discharge performance of the energy storage element is predicted based on the predicted voltage behavior; The voltage behavior is predicted by dividing the energizing pattern into each interval along the time axis. as well as The prediction of voltage behavior is stopped when the change in current in the energizing mode is less than a threshold.

9. A prediction program that causes a computer to perform the following processing: The energy storage element model is used to predict the voltage behavior of the energy storage element when it is energized in a specified energizing mode; The charge and discharge performance of the energy storage element is predicted based on the predicted voltage behavior; The voltage behavior is predicted by dividing the energizing mode into each interval along the time axis; and The prediction of voltage behavior is stopped when the change in current in the energizing mode is less than a threshold.

10. A prediction device comprising: The first prediction unit uses a storage element model to predict the voltage behavior of the storage element when it is energized in a specified energizing mode; and The prediction unit predicts the charge and discharge performance of the energy storage element based on the voltage behavior predicted by the first prediction unit. The first prediction unit divides the power-on mode into multiple periods and predicts the voltage behavior for each period. The time width during which the change in current in the power-on mode is less than a threshold is longer than the time width during which the change in current in the power-on mode is greater than a specified value.

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