JPWO2020100982A1 - Management device for power storage element, power storage device, vehicle, and management method for power storage element - Google Patents

Abstract

The BMS 50 of the power storage element 12 has a shunt resistor 60 connected in series with the power storage element 12, and the potential difference between two measurement positions 61 (61L, 61R) separated in the current flow direction in the shunt resistance 60. A current sensor 51 for detecting and measuring a current value and a management unit 55 are provided, and the management unit 55 sets the SOC of the power storage element 12 estimated based on the current value at two positions 61 (61L, 61R). The BMS 50 performs a correction process that corrects based on the measurement error of the current sensor 51 caused by the temperature gradient between the two.

Description

The present invention relates to a power storage element management device, a power storage device, a vehicle, and a method for managing the power storage element.

Conventionally, a current integration method is known as a method for estimating a state of charge (SOC) of a power storage element. The current integration method is a method in which the charge / discharge current of a power storage element is constantly measured by a current sensor to measure the amount of power flowing in and out of the power storage element, and the SOC is estimated by adding or subtracting this from the initial capacity.

The above-mentioned current sensor has a resistor (shunt resistor) connected in series with the power storage element, and measures the current value by detecting the potential difference between two positions of the resistor separated in the current flow direction. Things are known. In such a current sensor, a temperature gradient is generated between the two positions, and an electromotive force due to the Seebeck effect may cause a measurement error of the current value. If a current value measurement error occurs, the SOC estimation accuracy will decrease.

Therefore, conventionally, attempts have been made to suppress the influence of the Seebeck effect (see, for example, Patent Document 1). Specifically, in the technique described in Patent Document 1, a shunt resistor having a pair of current terminals and a pair of voltage terminals for detecting a voltage drop generated by a current energized between the pair of current terminals. In the above, a heat transfer inhibiting means for inhibiting a thermal influence is provided between each current terminal and a voltage terminal. The technique described in Patent Document 1 suppresses the occurrence of temperature difference by heat transfer inhibiting means.

Japanese Unexamined Patent Publication No. 2011-047721

However, in the technique described in Patent Document 1 described above, it is necessary to provide a heat transfer inhibiting means between the current terminal and the voltage terminal, which complicates the configuration of the shunt resistor.
In the present specification, a technique for suppressing the influence of the Seebeck effect when estimating the charging state of the power storage element based on the current value with a simple configuration is disclosed.

It is a management device for a power storage element, has a resistor connected in series with the power storage element, and measures the current value by detecting the potential difference between two positions separated in the current flow direction in the resistor. A current sensor and a management unit are provided, and the management unit sets the charging state of the power storage element estimated based on the current value to the current generated due to a temperature gradient between the two positions. Performs correction processing that corrects based on the measurement error of the sensor.

The influence of the Seebeck effect when estimating the charging state of the power storage element based on the current value can be suppressed with a simple configuration.

Schematic diagram of the power storage device according to the first embodiment and the automobile equipped with the power storage device. An exploded perspective view of the power storage device Top view of the power storage element shown in FIG. Sectional view of line AA shown in FIG. 3A A perspective view showing a state in which the power storage element is housed in the main body of FIG. A perspective view showing a state in which a bus bar is attached to the power storage element of FIG. Schematic diagram showing the electrical configuration of the power storage device Schematic diagram of current sensor Graph showing changes in current value after parking of vehicle (when measurement error occurs when current value is measured large) Graph showing changes in current value after parking of vehicle (when current value is small and measurement error occurs) Flow chart of correction process Schematic diagram of the current sensor according to the second embodiment OCV-SOC curve of iron-based power storage element

(Outline of this embodiment)
(1) A management device for a power storage element, which has a resistor connected in series with the power storage element, and detects a potential difference between two positions separated in the current flow direction in the resistor to detect a current value. The control unit includes a current sensor for measuring the current value and a control unit, and the control unit generates a charge state of the power storage element estimated based on the current value due to a temperature gradient between the two positions. A correction process for correcting based on the measurement error of the current sensor is executed.

According to the above management device, the current value measured by the current sensor includes a measurement error due to the temperature gradient between the two positions of the resistor (measurement error due to the Seebeck effect), so charging. The accuracy of state estimation is reduced. However, according to the above management device, the charging state is corrected based on the measurement error of the current sensor due to the Seebeck effect, and as a result, the charging state can be estimated accurately.
That is, according to the above-mentioned management device, the influence of the Seebeck effect can be suppressed without reducing the measurement error of the current value by providing a heat transfer inhibiting means in the resistor as in the conventional case, so that the power storage element is based on the current value. The influence of the Seebeck effect when estimating the state of charge can be suppressed with a simple configuration.

(2) The power storage element is a start power storage element that supplies electric power to a starter that starts the engine of the vehicle, and the management unit determines the measurement error that occurs after the vehicle is parked in the correction process. It may be corrected based on.

When the vehicle is running, the temperature of the two positions of the resistor may be almost the same because the power storage element is warmed as a whole due to the heat of the engine or the heat generated by the power storage element itself. However, when the vehicle is parked, a temperature gradient is generated between the two positions depending on the configuration of the power storage element and the usage environment. Therefore, when the vehicle is parked, a measurement error of the current value is likely to occur.
Generally, the measurement error of the current value due to the Seebeck effect is very small, but if high accuracy is required for estimating the state of charge, the measurement error that occurs after the vehicle is parked is a factor in the estimation error of the state of charge for the following reasons. It cannot be ignored.
Reason 1: Since the current value of the dark current flowing from the power storage element to the vehicle after being parked is as small as several tens of mA, the influence of the Seebeck effect is relatively large. In experiments conducted by the inventors of the present application, a measurement error of about 10 mA occurred due to a temperature gradient of 1 ° C. Normally, when a vehicle is parked, a temperature gradient of 2 ° C. to 3 ° C. occurs. Assuming that the dark current is 20 mA, the measured current value may be more than twice the current value (20 mA) that should be measured.
Reason 2: Since the vehicle is generally parked for a longer period of time than it is running, the measurement error that occurs after the vehicle is parked greatly affects the estimation error of the charged state.
According to the above-mentioned management device, since the estimation error of the state of charge generated after the vehicle is parked is corrected, the effect of suppressing the influence of the Seebeck effect becomes remarkable.

(3) In the correction process, the management unit may correct the charging state based on the measurement error generated during the period when the current value measured by the current sensor is equal to or less than the first threshold value.

Generally, the measurement error of the current value due to the Seebeck effect is very small, but when the current value is equal to or less than the first threshold value, the influence of the Seebeck effect becomes relatively large and cannot be ignored as a factor of estimation error of the charging state.
According to the above-mentioned management device, since the charging state is corrected based on the measurement error generated during the period when the current value is equal to or less than the first threshold value, the effect of suppressing the influence of the Seebeck effect becomes remarkable.

(4) The management unit may correct the charging state when the amount of change in the current value measured by the current sensor per unit time is larger than the second threshold value.

Even if the current value falls below the first threshold value, a temperature gradient does not always occur between the two positions of the resistor (the Seebeck effect does not always occur).
Whether or not the Seebeck effect occurs can be determined from the amount of change in the current value measured by the current sensor per unit time (the slope of the graph with the horizontal axis as time and the vertical axis as the current value). Specifically, when there is a temperature gradient between the two positions of the resistor (when the Seebeck effect occurs), the temperatures at those two positions gradually become uniform over time. , The Seebeck effect gradually converges. Therefore, when the Seebeck effect occurs, the current value changes with the passage of time. Therefore, the amount of change in the measured current value per unit time becomes large to some extent. Therefore, it can be determined whether or not the Seebeck effect is generated depending on whether or not the amount of change in the current value per unit time is larger than the second threshold value.
According to the above management device, the charging state is corrected when the amount of change in the current value per unit time is larger than the second threshold value (when the Seebeck effect occurs), so that the Seebeck effect does not occur. It is possible to prevent the correction from being performed.

(5) In the correction process, the management unit changes the current value per unit time from the time when the current value measured by the current sensor drops to the value equal to or lower than the first threshold value. The correction value of the charging state may be determined based on the time until the value becomes equal to or less than the threshold value of and the amount of change in the current value during that period.

The estimation error of the charging state due to the Seebeck effect is when the current value drops below the first threshold value and then when the amount of change in the current value per unit time falls below the second threshold value (in other words). The time until the Seebeck effect converges) can be expressed by the area of the triangle whose base is the base and the amount of change in the current value during that period is the height.
According to the above management device, since the area of the triangle described above is used as the correction value, the charging state can be corrected based on the measurement error of the current sensor.

(6) The management unit measures a current value larger than the first threshold value by the current sensor before the amount of change in the current value measured by the current sensor per unit time becomes equal to or less than the second threshold value. If this is done, the correction process may be stopped.

Even if the current value drops below the first threshold value, the power storage element may be used before the Seebeck effect converges. Normally, when a power storage element is used, a current larger than the first threshold value flows. When the current value is larger than the first threshold value, the measurement error of the current value due to the Seebeck effect is negligible.
According to the above management device, after the current value drops below the first threshold value, before the amount of change in the current value measured by the current sensor per unit time falls below the second threshold value (Seebeck effect converges). If a current value larger than the first threshold value is measured in the previous), the correction process is stopped, so that unnecessary correction can be suppressed.

(7) In the correction process, the management unit may correct the charging state based on the measurement error and the temperature difference between the two positions.

Even if the current value falls below the first threshold value, a temperature gradient does not always occur between the two positions of the resistor (the Seebeck effect does not always occur). Whether or not the Seebeck effect is generated can be judged from the temperature difference between the two positions of the resistor. Specifically, when the Seebeck effect occurs, the temperature difference between the two positions of the resistor becomes large to some extent, so it can be determined whether or not the Seebeck effect occurs based on the temperature difference between the two positions. ..
According to the above-mentioned management device, since the charging state is corrected based on the temperature difference between the two positions, it is possible to suppress that the correction is performed even though the Seebeck effect is not generated.

(8) A temperature sensor for measuring the temperature of the two positions is provided, and the management unit corrects the charging state when the temperature difference between the two positions is larger than the third threshold value in the correction process. May be good.

According to the above management device, the estimation error is corrected when the temperature difference between the two positions is larger than the third threshold value (when the Seebeck effect occurs), so that the correction is performed even though the Seebeck effect does not occur. It can be suppressed from being done.

(9) In the correction process, the management unit starts when the current value measured by the current sensor drops to a value equal to or lower than the first threshold value, and thereafter the temperature difference between the two positions becomes the third threshold value. The correction value of the charging state may be determined based on the time until it becomes the following and the amount of change in the current value during that time.

The estimation error of the state of charge due to the Seebeck effect is when the current value drops below the first threshold and then when the temperature difference between the two positions of the resistor falls below the third threshold ( In other words, the time until the Seebeck effect converges) can be expressed by the area of the triangle whose base is the base and the amount of change in the current value during that period is the height.
According to the above management device, since the area of the triangle described above is used as the correction value, the charging state can be corrected based on the measurement error of the current sensor.

(10) The management unit measured a current value larger than the first threshold value by the current sensor before the temperature difference between the two positions measured by the temperature sensor became equal to or less than the third threshold value. In that case, the correction process may be stopped.

Even if the current value drops below the first threshold value, the power storage element may be used before the Seebeck effect converges. Normally, when a power storage element is used, a current larger than the first threshold value flows. When the current value is larger than the first threshold value, the measurement error of the current value due to the Seebeck effect is negligible.
According to the above management device, after the current value drops below the first threshold value and before the temperature difference between the two positions measured by the temperature sensor falls below the third threshold value (before the Seebeck effect converges). When a current value larger than the first threshold value is measured, the correction process is stopped, so that unnecessary correction can be suppressed.

(11) A storage unit for storing a correction value used for correcting the charging state is provided, and the management unit corrects the charging state using the correction value stored in the storage unit in the correction processing. You may.

In many cases, the correction value will be a substantially constant value. Therefore, if the correction value is determined in advance by an experiment or the like and stored in the storage unit, it is not necessary to obtain the correction value each time the correction is made. Therefore, the correction process is simplified.

(12) In the management unit, after the current value measured by the current sensor drops to the value equal to or lower than the first threshold value, the current value larger than the first threshold value is set by the current sensor before a predetermined time elapses. If it is measured, the correction process may be stopped.

Even if the current value drops below the first threshold value, the power storage element may be used before the Seebeck effect converges. Normally, when a power storage element is used, a current larger than the first threshold value flows. Since the correction value stored in the storage unit is determined on the assumption that the power storage element is not used until the Seebeck effect converges, when the power storage element is used before the Seebeck effect converges (the first by the current sensor). Even when a current value larger than the threshold value is measured), if the estimation error is corrected using the correction value, it may be corrected inappropriately.
According to the above management device, the power storage element is used after the current value drops below the first threshold value and before a predetermined time (time determined in advance by experiments or the like as the time required for the convergence of the Seebeck effect) elapses. In that case, the correction process is stopped, so that the possibility that the charging state is improperly corrected can be reduced.

(13) The power storage device includes a power storage element and the management device according to any one of claims 1 to 12.

According to the above-mentioned power storage device, the influence of the Seebeck effect when estimating the charging state of the power storage element based on the current value can be suppressed by a simple configuration.

(14) The power storage element may have a plateau region in which the change in the open circuit voltage is small with respect to the change in the state of charge.

Since the current is constantly measured in the current integration method, the measurement error of the current sensor may accumulate and become inaccurate gradually. For this reason, conventionally, the state of charge estimated by the current integration method is obtained by utilizing the fact that there is a relatively accurate correlation between the open circuit voltage (OCV: Open Circuit Voltage) of the power storage element and the state of charge (SOC). Correction is performed according to the state of charge estimated from the open circuit voltage.
However, as shown in FIG. 12, some power storage elements have an OCV-SOC curve representing the relationship between the open circuit voltage and the state of charge having a plateau region (for example, an iron-based power storage element). The plateau region refers to a region in which the amount of change in OCV with respect to the amount of change in SOC is small in the OCV-SOC curve showing the correlation between OCV and SOC. Specifically, for example, a region in which the amount of change in OCV with respect to the amount of change in SOC is 2 [mV /%] or less is referred to as a plateau region.
When the OCV-SOC curve has a plateau region, it is difficult to accurately identify the state of charge corresponding to the open circuit voltage. Therefore, in the case of a power storage element having an OCV-SOC curve having a plateau region, it is more required to improve the estimation accuracy of the current integration method.
According to the above-mentioned power storage device, the charging state is corrected based on the measurement error of the current sensor caused by the temperature gradient between the two positions, so that the charging state can be estimated accurately. Therefore, it is particularly useful in the case of a power storage element in which the OCV-SOC curve has a plateau region.

(15) A vehicle equipped with a power storage device, the power storage device is housed in a storage room in which the engine of the vehicle is housed.

When the power storage device is housed in the engine storage chamber, it is easily affected by the heat of the engine, so that a temperature gradient is generated and a measurement error of the current sensor is likely to occur.
According to the above vehicle, the charging state is corrected based on the measurement error of the current sensor caused by the temperature gradient between the two positions, so that the charging state is charged even if the power storage element is housed in the engine housing chamber. Can be estimated accurately.

(16) A method for managing a power storage element, which has a resistor connected in series with the power storage element, and detects a potential difference between two positions separated in the current flow direction in the resistor to detect a current value. Based on the step of estimating the charging state of the power storage element based on the current value measured by the current sensor, and the measurement error of the current sensor caused by the temperature gradient between the two positions. The step of correcting the charging state includes.

According to the above management method, the influence of the Seebeck effect when estimating the charging state of the power storage element based on the current value can be suppressed with a simple configuration.

The invention disclosed herein can be realized in various aspects such as devices, methods, computer programs for realizing the functions of these devices or methods, recording media on which the computer programs are recorded, and the like.

<One Embodiment>
One embodiment will be described with reference to FIGS. 1 to 10.
A power storage device 1 according to the first embodiment and an automobile 2 (an example of a vehicle) including the power storage device 1 will be described with reference to FIG. The automobile 2 shown in FIG. 1 is an engine automobile and includes a starter for starting the engine. The power storage device 1 is a start power storage device mounted on the automobile 2 to supply electric power to the starter. Although FIG. 1 shows a case where the power storage device 1 is housed in the engine room 2A (an example of a storage room), the power storage device 1 may be housed under the floor or in the trunk of the living room.

(1) Configuration of Power Storage Device As shown in FIG. 2, the power storage device 1 includes an exterior body 10 and a plurality of power storage elements 12 housed inside the exterior body 10. The exterior body 10 is composed of a main body 13 made of a synthetic resin material and a lid body 14. The main body 13 has a bottomed cylindrical shape, and is composed of a bottom surface portion 15 having a rectangular shape in a plan view and four side surface portions 16 rising from its four sides to form a cylindrical shape. An upper opening 17 is formed at the upper end portion by the four side surface portions 16.

The lid body 14 has a rectangular shape in a plan view, and the frame body 18 extends downward from its four sides. The lid 14 closes the upper opening 17 of the main body 13. A substantially T-shaped protrusion 19 in a plan view is formed on the upper surface of the lid 14. The positive electrode external terminal 20 is fixed to one corner of the two locations where the protrusion 19 is not formed on the upper surface of the lid 14, and the negative electrode external terminal 21 is fixed to the other corner.

The power storage element 12 is a rechargeable secondary battery, specifically, for example, a lithium ion battery. More specifically, the power storage element 12 is a so-called iron-based lithium ion battery containing lithium iron phosphate (LFP) in the positive electrode active material of the electrode body 23, which will be described later.

As shown in FIGS. 3A and 3B, the power storage element 12 has an electrode body 23 housed in a rectangular parallelepiped case 22 together with a non-aqueous electrolyte. The case 22 is composed of a case main body 24 and a cover 25 that closes an opening above the case main body 24.
Although not shown in detail, the electrode body 23 is a porous resin between a negative electrode element in which an active material is applied to a base material made of copper foil and a positive electrode element in which an active material is applied to a base material made of aluminum foil. A separator made of film is arranged. All of these are band-shaped, and the negative electrode element and the positive electrode element are wound flat so as to be accommodated in the case body 24 in a state where the negative electrode element and the positive electrode element are displaced on opposite sides in the width direction with respect to the separator. There is.

A positive electrode terminal 27 is connected to the positive electrode element via a positive electrode current collector 26. The negative electrode terminal 29 is connected to the negative electrode element via the negative electrode current collector 28. The positive electrode current collector 26 and the negative electrode current collector 28 have a flat plate-shaped pedestal portion 30 and leg portions 31 extending from the pedestal portion 30. A through hole is formed in the pedestal portion 30. The leg 31 is connected to a positive electrode element or a negative electrode element. The positive electrode terminal 27 and the negative electrode terminal 29 have a terminal main body portion 32 and a shaft portion 33 protruding downward from the center portion of the lower surface thereof. Among them, the terminal body portion 32 and the shaft portion 33 of the positive electrode terminal 27 are integrally molded with aluminum (single material). In the negative electrode terminal 29, the terminal body portion 32 is made of aluminum and the shaft portion 33 is made of copper, and these are assembled. The terminal body 32 of the positive electrode terminal 27 and the negative electrode terminal 29 is arranged at both ends of the cover 25 via a gasket 34 made of an insulating material, and is exposed to the outside from the gasket 34.

As shown in FIG. 4, a plurality of (for example, 12) power storage elements 12 are housed in the main body 13 in a state of being arranged side by side in the width direction. Here, three power storage elements 12 are set as one set from one end side to the other end side (directions of arrows Y1 to Y2) of the main body 13, and in the same set, the terminal polarities of adjacent power storage elements 12 are the same, and adjacent sets. They are arranged so that the terminal polarities of adjacent power storage elements 12 are opposite to each other. In the three power storage elements 12 (first set) located closest to the arrow Y1, the arrow X1 side is the negative electrode and the arrow X2 side is the positive electrode. In the three power storage elements 12 (second set) adjacent to the first set, the arrow X1 side is the positive electrode and the arrow X2 side is the negative electrode. Further, the third group adjacent to the second group has the same arrangement as the first group, and the fourth group adjacent to the third group has the same arrangement as the second group.

As shown in FIG. 5, terminal bus bars (connecting members) 36 to 40 as conductive members are connected to the positive electrode terminal 27 and the negative electrode terminal 29 by welding. On the arrow X2 side of the first set, the positive electrode terminal 27 group is connected by the first bus bar 36. Between the first group and the second group, the negative electrode terminal 29 group of the first group and the positive electrode terminal 27 group of the second group are connected by the second bus bar 37 on the arrow X1 side. Between the second group and the third group, the negative electrode terminal 29 group of the second group and the positive electrode terminal 27 group of the third group are connected by the third bus bar 38 on the arrow X2 side. Between the third group and the fourth group, the negative electrode terminal 29 group of the third group and the positive electrode terminal 27 group of the fourth group are connected by the fourth bus bar 39 on the arrow X1 side. On the arrow X2 side of the fourth set, the negative electrode terminal 29 group is connected by the fifth bus bar 40.

Referring to FIG. 2 together, the first bus bar 36 located at one end of the electric flow includes the first electronic device 42A (for example, a fuse), the second electronic device 42B (for example, a relay), the bus bar 43, and the bus bar terminal (FIG. 2). It is connected to the positive electrode external terminal 20 via (not shown). The fifth bus bar 40 located at the other end of the flow of electricity is connected to the negative electrode external terminal 21 via the bus bars 44A and 44B and the negative electrode bus bar terminal (not shown). As a result, each power storage element 12 can be charged and discharged via the positive electrode external terminal 20 and the negative electrode external terminal 21. The electronic devices 42A and 42B and the bus bars 43, 44A and 44B for connecting electric components are attached to a circuit board unit 41 arranged above a plurality of power storage elements 12 arranged in a stacked manner. The bus bar terminal is arranged on the lid 14.

(2) Electrical Configuration of Power Storage Device As shown in FIG. 6, the power storage device 1 includes the above-mentioned plurality of power storage elements 12 and a BMS (Battery Management System) 50 that manages the power storage elements 12. BMS50 is an example of a management device.

The BMS 50 includes a current sensor 51, a voltage sensor 52, and a management unit 55.
The current sensor 51 is connected in series with the power storage element 12. The current sensor 51 measures the charge / discharge current of the power storage element 12 and outputs it to the management unit 55. The specific configuration of the current sensor will be described later.
The voltage sensor 52 is connected to each power storage element 12 in parallel. The voltage sensor 52 measures the terminal voltage of each power storage element 12 and outputs it to the management unit 55.

The management unit 55 includes a CPU 55B, a ROM 55C (an example of a storage unit), a microcomputer 55A (so-called microcomputer) in which a RAM 55D and the like are integrated into a single chip, a communication unit 55E, and the like. These are mounted on the circuit board unit 41 shown in FIG. The ROM 55C stores a management program and various data. The management unit 55 manages the power storage element 12 by executing the management program stored in the ROM 55C. The communication unit 55E is an interface for the CPU 55B to communicate with the system (for example, ECU: Engine Control Unit) on the vehicle 2 side.

(3) Configuration of Current Sensor The configuration of the current sensor 51 will be described with reference to FIG. 7. The current sensor 51 determines the potential difference between the shunt resistor 60 (an example of a resistor) connected in series with the power storage element 12 and the two measurement positions 61 (61L, 61R) separated from each other in the current flow direction in the shunt resistor 60. It has a detection circuit 62 for detection, and calculates a current value from the resistance value of the shunt resistor 60 and the potential difference between the two measurement positions 61. The two measurement positions 61 are examples of positions, respectively.

(4) Processing executed by the management unit The management unit 55 executes the estimation processing and the correction processing described below.

(4-1) Estimating process The estimation process is a process of estimating the SOC of the power storage element 12 by the current integration method. The current integration method is a method in which the charge / discharge current of the power storage element 12 is constantly measured by the current sensor 51 to measure the amount of power flowing in and out of the power storage element 12, and the SOC is estimated by adding or subtracting this from the initial capacity. .. The SOC estimated by the current integration method is an example of "the state of charge of the power storage element estimated based on the current value".

(4-2) Correction process As shown in FIG. 7, bus bars B1 and B2 are connected to both ends of the shunt resistor 60. Here, in FIG. 7, the left side of the shunt resistor 60 is the power storage element 12 side, and the right side is the negative electrode external terminal 21 side. In the example shown in FIG. 7, it is assumed that the bus bar B1 connected to the left side of the shunt resistor 60 has a smaller heat capacity than the bus bar B2 connected to the right side.

Normally, when the engine is operating, is charged quickly, or when a large current is discharged, the power storage device 1 is warmed as a whole by the heat of the engine or the heat generated by the power storage element 12, so that the temperature of the bus bar B1 and the temperature of the bus bar B2 The temperature is almost the same. However, if the heat capacity of the bus bar B1 is smaller than that of the bus bar B2, the bus bar B1 generates more heat than the bus bar B2 when the vehicle is parked and the temperatures of the bus bar B1 and the bus bar B2 decrease. Therefore, the temperature of the bus bar B1 is higher than that of the bus bar B2.

When the temperature of the bus bar B1 is higher than that of the bus bar B2, the temperature of the measurement position 61L on the left side of the shunt resistor 60 is higher than that of the measurement position 61R on the right side. Due to the electromotive force of the Seebeck effect due to this temperature gradient, a current in the left direction (discharge direction) flows through the shunt resistor 60. Therefore, the current value measured by the current sensor 51 is the sum of the current value of the discharge current of the power storage element 12 and the current value due to the Seebeck effect, resulting in a measurement error in which the current value is measured larger than originally intended.

The measurement error of the current value is not limited to the large measurement error. For example, the temperature of the bus bar B2 may be higher than that of the bus bar B1 because the heat capacity of the bus bar B2 is smaller than that of the bus bar B1. In that case, the current flows in the right direction (charging direction). Therefore, the current value measured by the current sensor 51 is obtained by subtracting the current value due to the Seebeck effect from the current value of the discharge current of the power storage element 12, and a measurement error occurs in which the current value is measured smaller than the original value.

The cause of the temperature difference between the bus bar B1 and the bus bar B2 is not limited to the difference in heat capacity. For example, even if the heat capacities of the bus bar B1 and the bus bar B2 are the same, a temperature difference may occur depending on the environment around the power storage device 1. For example, since the bus bar B1 is closer to the engine than the bus bar B2, it is conceivable that the temperature of the bus bar B1 is higher than that of the bus bar B2 due to the heat of the engine.

If a measurement error of the current value occurs due to the Seebeck effect, the SOC estimation accuracy decreases. Therefore, the management unit 55 uses the SOC estimated by the current integration method as a measurement error of the current sensor 51 caused by the temperature gradient between the two measurement positions 61 (current sensor caused by the Seebeck effect). The correction process for correcting based on the measurement error of 51) is executed. Hereinafter, a specific description will be given.

(4-2-1) Outline of correction processing FIG. 8 shows an example in which a measurement error occurs in which a large current value is measured. In FIG. 8, the solid line 65 shows the current value measured by the current sensor 51 (current value including the measurement error due to the Seebeck effect), and the dotted line 66 shows the current value measured when the Seebeck effect does not occur (essentially). The current value to be measured) is shown. The difference between the solid line 65 and the dotted line 66 corresponds to the measurement error of the current sensor 51 caused by the temperature gradient between the two measurement positions 61.

In FIG. 8, the time point T1 is the time when the automobile 2 is parked. When the automobile 2 is parked at the time point T1, the discharge current of the power storage element 12 gradually decreases. However, the discharge current does not completely reach 0 mA, and a minute dark current such as 20 mA flows even during parking.
The time point T2 is a time point when the current value drops below the first threshold value (for example, 100 mA). The first threshold is not limited to 100 mA and can be determined as appropriate. A measurement error of the current value due to the Seebeck effect also occurs in the period from the time point T1 to the time point T2, but since this period is relatively short and the current value is also relatively large, it can be ignored as an estimation error factor of SOC. Therefore, the management unit 55 does not correct the SOC for the period from the time point T1 to the time point T2 even if the automobile 2 is parked.

The time point T4 indicates the time point when the Seebeck effect has converged. When a temperature gradient occurs between the two measurement positions 61 (when the Seebeck effect occurs), the temperature of the two measurement positions 61 gradually becomes uniform over time, so that the Seebeck effect is exhibited. It gradually converges. Therefore, the current value measured by the current sensor 51 gradually decreases from the time point T2 to the time point T4.

Since the period from the time point T2 to the time point T4 is relatively long and the current value is very small (100 mA or less), it cannot be ignored as an estimation error factor of SOC. Therefore, the management unit 55 corrects the SOC based on the measurement error of the current sensor 51 that occurs in the period from the time point T2 to the time point T4 (the period in which the current value is 100 mA or less). Specifically, the area of the triangle 67 shown by hatching in FIG. 8 corresponds to the SOC estimation error caused by the measurement error of the current sensor 51 that occurred during the period from the time point T2 to the time point T4. Therefore, the management unit 55 corrects the SOC by subtracting the area of the triangle 67 from the SOC estimated by the current integration method.

However, even if the current value drops to 100 mA or less at the time point T2, the power storage element 12 may be used before the Seebeck effect converges. Normally, when the power storage element 12 is used, a current larger than 100 mA flows. When the current value is larger than 100 mA, the measurement error of the current value due to the Seebeck effect is negligible. Therefore, the management unit 55 cancels the correction process when a current value larger than 100 mA is measured before the Seebeck effect converges after the current value drops to 100 mA or less.

FIG. 9 shows an example in which a measurement error occurs when the current value is small. In this case, the SOC is estimated to be smaller than the original due to the measurement error of the current sensor 51. Therefore, the management unit 55 calculates the SOC by adding the area of the triangle 68 shown by hatching in FIG. 9 to the SOC estimated by the current integration method. to correct.

(4-2-2) Flow of correction processing The flow of correction processing will be described with reference to FIG. In the following description, it is assumed that the current value is measured by the current sensor 51 at intervals of several seconds to several tens of seconds while the automobile 2 is parked.

In S101, the management unit 55 determines whether or not the automobile 2 is parked.
Specifically, the management unit 55 receives a signal indicating the state of the engine from the ECU of the automobile 2 at regular time intervals, and determines from the signal whether or not the automobile 2 is parked. The method for determining whether or not the automobile 2 is parked is not limited to this, and can be determined by an appropriate method. For example, if the vibration of the engine is no longer detected, it may be determined that the automobile 2 is parked.
When the automobile 2 is parked, the management unit 55 proceeds to S102, and when the automobile 2 is not parked, the management unit 55 executes S101 again after a predetermined time has elapsed.

In S102, the management unit 55 waits until the next current value is measured by the current sensor 51, and proceeds to S103 when the current value is measured.
In S103, the management unit 55 determines whether or not the measured current value is 100 mA or less, proceeds to S104 if it is 100 mA or less, returns to S102 if it is greater than 100 mA, and repeats the process.

In S104, the management unit 55 starts counting the time and stores the first measured current value as a current value of 100 mA or less in the RAM 55D.
For example, assume that the current value measured last time is 103 mA and the current value measured this time is 98 mA. In this case, the management unit 55 determines that the current value has dropped to 100 mA or less in S103 described above, starts counting the time in S104, and stores 98 mA in the RAM 55D.

In S105, the management unit 55 determines whether or not the Seebeck effect is occurring. Whether or not the Seebeck effect is generated can be determined from the amount of change in the current value measured by the current sensor 51 per unit time (the slope of the graph with the horizontal axis as time and the vertical axis as the current value). In the following description, the amount of change in the current value per unit time is referred to as the slope of the current value.

Specifically, when the Seebeck effect does not occur, the dark current becomes substantially constant (for example, 20 mA), so that the slope of the measured current value becomes almost zero. On the other hand, when the Seebeck effect occurs, the current value gradually decreases, so that the absolute value of the slope of the current value increases to some extent. Therefore, it can be determined whether or not the Seebeck effect is generated by whether or not the absolute value of the slope of the current value is larger than the second threshold value (for example, 0.1).

After determining in S103 that the current value has dropped to 100 mA or less, the management unit 55 waits until a predetermined time (for example, 3 minutes) elapses. In FIG. 8, the time point T3 indicates the time point when a predetermined time has elapsed. The management unit 55 may not wait until the predetermined time elapses, but may wait until the current value is measured a predetermined number of times (for example, 10 times).

When the predetermined time elapses, the management unit 55 calculates the slope from the current value measured during that time, and if the calculated slope is larger than the second threshold value, determines that the Seebeck effect has occurred and proceeds to S106. When the inclination is equal to or less than the second threshold value, the management unit 55 determines that the Seebeck effect has not occurred (or even if it has occurred, it can be ignored), and cancels this process.

In S106, the management unit 55 waits until the next current value is measured by the current sensor 51, and proceeds to S107 when the current value is measured.
In S107, the management unit 55 determines whether or not the measured current value is larger than 100 mA. When the current value is 100 mA or less, the management unit 55 determines that the power storage element 12 is not used and proceeds to S108. When the current value is greater than 100 mA, the management unit 55 determines that the power storage element 12 has been used and cancels this process.

In S108, the management unit 55 determines whether or not the Seebeck effect has converged.
Specifically, when the Seebeck effect converges, the current value becomes constant at about 20 mA, so that the absolute value of the slope of the current value becomes almost zero. Therefore, the management unit 55 calculates the slope of the current value from the current value measured last time and the current value measured this time. The slope may be calculated from the current values measured by the most recent three or more measurements including this time.
The management unit 55 determines whether or not the absolute value of the slope of the calculated current value is equal to or less than the second threshold value, and if it is equal to or less than the second threshold value, determines that the Seebeck effect has converged and proceeds to S109. If it is larger than the second threshold value, the process returns to S106 and the process is repeated.

In S109, the management unit 55 determines a correction value for correcting the SOC.
Specifically, the management unit 55 starts from the current value (for example, 98 mA) stored in the RAM 55D in S104, and then T4 (when the Seebeck effect converges) when the absolute value of the slope of the current value becomes equal to or less than the second threshold value. ) Is subtracted to obtain the amount of change in the current value (height of the triangle 67) during that period. The management unit 55 determines the correction value (area of the triangle 67) by dividing the product of the time from the time point T2 to the time point T4 (the base of the triangle 67) and the amount of change in the current value described above by 2. The correction value can be rephrased as a value obtained by integrating the measurement errors of the current sensor 51 caused by the temperature gradient between the two measurement positions 61.

In S110, the management unit 55 corrects the SOC by subtracting the correction value determined in S109 from the SOC estimated by the current integration method.
As shown in FIG. 9 described above, when the current value is small and a measurement error occurs, the current value at the time point T5 (when the Seebeck effect converges) is subtracted from the current value stored in the RAM 55D in S104. Since the amount of change in the current value is a negative value, the correction value is also a negative value. In this case, when the correction value is subtracted from the SOC, a negative value is subtracted, and as a result, a positive correction value is added.

(5) Effect of Embodiment According to BMS50, the SOC estimated by the current integration method is based on the measurement error of the current sensor 51 caused by the temperature gradient between the two measurement positions 61 of the shunt resistor 60. Since the correction is performed, the influence of the Seebeck effect can be suppressed without reducing the measurement error of the current value by providing the heat transfer inhibiting means in the shunt resistor 60 as in the conventional case. Therefore, the influence of the Seebeck effect when the SOC is estimated by the current integration method can be suppressed with a simple configuration.

According to the BMS 50, the SOC is corrected based on the measurement error of the current sensor 51 generated after the automobile 2 is parked, so that the effect of suppressing the influence of the Seebeck effect becomes remarkable.

According to the BMS 50, the SOC is corrected based on the measurement error of the current sensor 51 that occurs during the period when the current value is 100 mA or less (the period after the time point T2), so that the effect of suppressing the influence of the Seebeck effect becomes remarkable.

According to BMS50, the SOC is corrected when the absolute value of the slope of the current value is larger than the second threshold value (when the Seebeck effect occurs), so that the correction is performed even though the Seebeck effect does not occur. Can be suppressed.

According to the BMS 50, since the area of the triangle 67 shown by hatching in FIG. 8 is used as the correction value, the SOC can be corrected based on the measurement error of the current sensor 51.

According to the BMS 50, if the power storage element 12 is used after the current value drops to 100 mA or less and before the Seebeck effect converges, the correction process is stopped, so that unnecessary correction can be suppressed.

According to the power storage device 1, the influence of the Seebeck effect can be suppressed without reducing the measurement error of the current value by providing the shunt resistor 60 with the heat transfer inhibiting means as in the conventional case. Therefore, the influence of the Seebeck effect when the SOC is estimated by the current integration method can be suppressed with a simple configuration.

According to the power storage device 1, the SOC is corrected based on the measurement error of the current sensor 51 caused by the Seebeck effect, so that the SOC can be estimated accurately. Therefore, it is particularly useful in the case of the power storage element 12 in which the OCV-SOC curve has a plateau region.

According to the automobile 2, even if the power storage device 1 is housed in the engine room 2A of the automobile 2, the SOC can be estimated accurately.

<Embodiment 2>
As shown in FIG. 11, the BMS 50 according to the second embodiment includes a temperature sensor 70 that measures the temperature near the measurement position 61L of the shunt resistance 60, and a temperature sensor 71 that measures the temperature near the measurement position 61R. .. The management unit 55 according to the second embodiment determines whether or not the Seebeck effect is generated from the temperature difference between the two measurement positions 61.

Specifically, when the Seebeck effect occurs, the temperature difference between the two measurement positions 61 becomes large to some extent. Therefore, the management unit 55 determines whether or not the Seebeck effect is generated depending on whether or not the temperature difference between the two measurement positions 61 is larger than the third threshold value. The management unit 55 corrects the SOC when the current value drops to 100 mA or less and the temperature difference between the two measurement positions 61 is larger than the third threshold value (when the Seebeck effect occurs).

The SOC estimation error due to the measurement error of the current sensor 51 caused by the Seebeck effect is the temperature difference between the two measurement positions 61 of the shunt resistance 60 after the current value drops to 100 mA or less. It can be represented by the area of a triangle whose base is the time until the temperature falls below the threshold of 3 (in other words, when the Seebeck effect converges) and the amount of change in the current value during that period is the height. Therefore, the management unit 55 uses the area of the triangle as the correction value.

According to the BMS 50 according to the second embodiment, since the SOC is corrected based on the temperature difference between the two measurement positions 61, it is possible to suppress the correction from being performed even though the Seebeck effect is not generated.

According to the BMS 50, the SOC is corrected when the temperature difference between the two measurement positions 61 is larger than the third threshold value (when the Seebeck effect is generated), so that the correction is performed even though the Seebeck effect is not generated. Can be suppressed.

According to the BMS 50, since the area of the triangle described above is used as the correction value, the SOC can be corrected based on the measurement error of the current sensor 51.

According to the BMS 50, if the power storage element 12 is used after the current value drops to 100 mA or less and before the Seebeck effect converges, the correction process is stopped, so that unnecessary correction can be suppressed.

<Embodiment 3>
In the third embodiment, the SOC correction value is determined in advance by an experiment or the like and stored in the ROM 55C. In the management unit 55, when the current value is reduced to 100 mA or less and the Seebeck effect is generated (when the absolute value of the slope of the current value is larger than the second threshold value, or the temperature difference between the two measurement positions 61 is large. If it is larger than the third threshold value), the SOC is corrected using the correction value.
In many cases, the correction value will be a substantially constant value. Therefore, if the correction value is determined in advance by an experiment or the like and stored in the ROM 55C, it is not necessary to obtain the correction value each time the correction is performed. Therefore, the correction process is simplified.

However, even if the current value drops to 100 mA or less, the power storage element 12 may be used before the Seebeck effect converges. Since the correction value stored in the ROM 55C is determined on the premise that the power storage element 12 is not used until the Seebeck effect converges, the correction value is used even when the power storage element 12 is used before the Seebeck effect converges. If the SOC is corrected by using it, it may be corrected improperly.

Therefore, the management unit 55 uses the power storage element 12 after the current value drops to 100 mA or less and before a predetermined time (a time determined in advance by an experiment or the like as the time required for the convergence of the Seebeck effect) elapses. In the case (specifically, when a current value larger than 100 mA is measured by the current sensor 51), the correction process is stopped. Therefore, the possibility that the SOC is improperly corrected can be reduced.

<Other Embodiments>
The techniques disclosed herein are not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included in the technical scope disclosed herein.

(1) In the above embodiment, the management unit 55 determines whether or not the automobile 2 is parked, and when the automobile 2 is parked, determines whether or not the current value has dropped to 100 mA or less, and up to 100 mA or less. If it decreases, determine whether the Seebeck effect is occurring.

On the other hand, the management unit 55 may not determine whether or not the automobile 2 is parked. Specifically, the management unit 55 may determine whether or not the Seebeck effect occurs when the current value drops to 100 mA or less, regardless of whether or not the automobile 2 is parked.
Alternatively, it may not be determined whether or not the current value has dropped to 100 mA or less. Specifically, the management unit 55 may determine whether or not the Seebeck effect is occurring when the automobile 2 is parked, regardless of whether or not the current value has dropped to 100 mA or less.

(2) In the above embodiment, after determining that the current value has dropped to 100 mA or less, it is determined whether or not the Seebeck effect is occurring, but it is not necessary to determine whether or not the Seebeck effect is occurring. .. Specifically, when the current value drops to 100 mA or less, it may be considered that the Seebeck effect has occurred and the SOC estimation error may be corrected.

(3) In the above embodiment, if the engine is started before the Seebeck effect converges, the correction process is stopped (S107), but if the engine is started before the Seebeck effect converges, the engine is started. The SOC may be corrected by calculating the correction value between.

(4) In the first embodiment, it is determined that the Seebeck effect has converged when the slope of the current value is equal to or less than the second threshold value. On the other hand, when the Seebeck effect converges, the dark current becomes substantially constant. Therefore, for example, it may be determined that the Seebeck effect has converged when the current value is within a predetermined dark current ± 2 mA.
However, the dark current when the Seebeck effect converges may differ depending on the vehicle model. Therefore, when it is judged that the Seebeck effect has converged when the current value is within the predetermined dark current ± 2 mA, it is desirable to store the predetermined dark current for each vehicle type. On the other hand, if it is judged from the slope of the current value whether or not the Seebeck effect has converged, it can be judged whether or not the Seebeck effect has converged regardless of the vehicle type, which is more versatile.

(5) In the second embodiment, the case of measuring the temperatures of the measurement position 61L and the measurement position 61R of the shunt resistor 60 has been described as an example, but the temperatures of the bus bar B1 and the bus bar B2 may be measured. When a temperature sensor for measuring the temperature of the power storage element 12 is provided, the temperature measured by the temperature sensor may be used. When the automobile 2 is provided with a temperature sensor for measuring the temperature of the bus bar connecting the automobile 2 and the power storage device 1, the temperature measured by the temperature sensor may be used.

(6) In the third embodiment, the correction value is determined in advance by an experiment or the like and stored in the ROM 55C. On the other hand, instead of storing the correction value itself in the ROM 55C, the time until the Seebeck effect converges (for example, when the current value drops to 100 mA or less, the slope of the current value becomes equal to or less than the second threshold value). The time until time) is stored in the ROM55C, while the amount of change in the current value during that period is actually measured, and the product of the time stored in the ROM55C and the amount of change in the current value during that period is divided by 2. May be used as the correction value.
The ROM 55C stores the amount of change in the current value between the time when the current value drops to 100 mA or less and the time when the slope of the current value falls below the second threshold value, while the time until the Seebeck effect converges. May actually be measured.

(7) In the third embodiment, a case where the correction value stored in the ROM 55C is used as it is for correction has been described as an example. On the other hand, the correction value stored in the ROM 55C may be adjusted and used. For example, the correction value may be adjusted according to the vehicle type on which the power storage device 1 is mounted, or may be adjusted according to the internal temperature and the outside air temperature of the power storage device 1.

(8) In the above embodiment, the iron-based power storage element 12 has been described as an example of the power storage element 12, but the power storage element 12 is not limited to the iron-based one, and may be another lithium ion battery.

(9) Although the power storage element 12 for starting has been described as an example in the first embodiment, the application of the power storage element 12 is not limited to this. For example, the power storage element 12 may be mounted on an electric vehicle or a hybrid vehicle to supply electric power to auxiliary equipment, or may be a forklift or an unmanned transport vehicle (AGV: Automatic Guided Vehicle) traveling by an electric motor. It may be for a mobile body mounted on an electric motor or the like to supply electric power to an electric motor.
The power storage element 12 may be used in an uninterruptible power supply (UPS), or may be used in a mobile terminal or the like. It may be a power storage device used for peak shift, or it may be a power storage device that stores renewable energy.

(10) In the above embodiment, after the automobile 2 is parked, it occurs in the period from when the current value drops to 100 mA or less to when the amount of change in the current value per unit time becomes equal to or less than the second threshold value. The case where the SOC is corrected based on the measurement error of the current sensor 51 has been described as an example. However, the period for correcting the SOC is not limited to this, and the SOC may be corrected at any period as long as it is a period between the time when the vehicle 2 is parked and the time when the engine of the vehicle 2 is started.

For example, when the automobile 2 is parked at night, the temperature of the power storage device 1 drops due to the low air temperature (environmental temperature). The bus bar connected to one end of the shunt resistor 60 is housed inside the power storage device 1, but the bus bar connected to the other end is outside the power storage device 1 to connect to the automobile 2 in the morning. When the temperature rises, the bus bar connected to the other end rises first. The SOC estimation error due to the Seebeck effect generated at this time may be corrected.

(11) In the above embodiment, the case where the SOC is corrected based on the measurement error of the current sensor caused by the temperature gradient between the two measurement positions 61 has been described as an example, but this measurement error is controlled by another control. It may be used for. For example, the BMS 50 generally operates by the electric power supplied from the power storage element 12. Therefore, the BMS 50 shifts to the sleep mode when the automobile 2 is parked. In the sleep mode, power consumption is suppressed by lengthening the cycle for measuring the current value and the voltage value. When a current of a predetermined value or more flows, the BMS 50 determines that the engine has been started and returns to the normal mode (mode in which the measurement cycle is short). At this time, if the current value includes a measurement error, it may return to the normal mode even though it should not return to the normal mode. If the automobile 2 is parked and the engine is stopped, the battery is not charged, so that the battery may run out when the normal mode is restored.
Therefore, the current value measured by the current sensor 51 may be corrected based on the measurement error, and the corrected current value may be used to avoid returning from the sleep mode to the normal mode. This can prevent the battery from running out.

(12) Although the lithium ion battery has been described as an example of the power storage element in the first embodiment, the power storage element is not limited to this. For example, the power storage element may be a capacitor that involves an electrochemical reaction.

1 power storage device, 2 automobile (example of vehicle), 2A engine room 2A (example of accommodation room), 12 power storage element, 23 electrode body, 50 BMS (example of management device), 51 current sensor, 55 management unit, 55C ROM (Example of storage unit), 60 shunt resistance (example of resistor), 70 temperature sensor, 71 ... Temperature sensor

Claims (16)

It is a management device for power storage elements.
A current sensor that has a resistor connected in series with the power storage element and measures the current value by detecting the potential difference between two positions separated in the current flow direction in the resistor.
With the management department
With
The management unit corrects the charging state of the power storage element estimated based on the current value based on the measurement error of the current sensor caused by the temperature gradient between the two positions. A management device that runs. The management device for a power storage element according to claim 1.
The power storage element is a start power storage element that supplies electric power to a starter that starts the engine of a vehicle.
The management unit is a management device that corrects the correction process based on the measurement error that occurs after the vehicle is parked. The management device for a power storage element according to claim 1 or 2.
The management unit is a management device that corrects the charging state based on the measurement error generated during the period when the current value measured by the current sensor is equal to or less than the first threshold value in the correction process. The management device for a power storage element according to claim 3.
The management unit is a management device that corrects the charging state when the amount of change in the current value measured by the current sensor per unit time is larger than the second threshold value. The management device for a power storage element according to claim 4.
In the correction process, the management unit starts when the current value measured by the current sensor drops to or less than the first threshold value, and thereafter the amount of change in the current value per unit time is equal to or less than the second threshold value. A management device that determines the correction value of the charging state based on the time until when the value is reached and the amount of change in the current value during that period. The management device for a power storage element according to claim 5.
When the management unit measures a current value larger than the first threshold value by the current sensor before the change amount of the current value measured by the current sensor per unit time becomes equal to or less than the second threshold value. Is a management device that cancels the correction process. The management device for a power storage element according to claim 3.
The management unit is a management device that corrects the charging state based on the measurement error and the temperature difference between the two positions in the correction process. The management device for a power storage element according to claim 7.
It is equipped with a temperature sensor that measures the temperature at the two positions.
The management unit is a management device that corrects the charging state when the temperature difference between the two positions is larger than the third threshold value in the correction process. The management device for a power storage element according to claim 8.
In the correction process, the management unit starts when the current value measured by the current sensor drops to the first threshold value or less, and then the temperature difference between the two positions becomes the third threshold value or less. A management device that determines the correction value of the charging state based on the time until the time and the amount of change in the current value during that time. The management device for a power storage element according to claim 9.
When the current sensor measures a current value larger than the first threshold value before the temperature difference between the two positions measured by the temperature sensor becomes equal to or less than the third threshold value, the management unit may use the control unit. A management device that cancels the correction process. The management device for a power storage element according to claim 3.
A storage unit for storing a correction value used for correcting the state of charge is provided.
The management unit is a management device that corrects the charging state by using the correction value stored in the storage unit in the correction process. The management device for a power storage element according to claim 11.
The management unit measures a current value larger than the first threshold value by the current sensor before a predetermined time elapses after the current value measured by the current sensor drops to the value equal to or lower than the first threshold value. If this is the case, the management device stops the correction process. Power storage element and
The management device according to any one of claims 1 to 12.
A power storage device equipped with. The power storage device according to claim 13.
The power storage element is a power storage device having a plateau region in which a change in open circuit voltage is small with respect to a change in charge state. A vehicle including the power storage device according to claim 13 or 14.
The power storage device is a vehicle housed in a storage room in which the engine of the vehicle is housed. It is a management method of power storage elements.
The current value measured by a current sensor that has a resistor connected in series with the power storage element and detects the potential difference between two positions separated in the current flow direction in the resistor and measures the current value. Based on the step of estimating the charging state of the power storage element,
A step of correcting the charging state based on the measurement error of the current sensor caused by the temperature gradient between the two positions, and
Management methods, including.

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