WO2017047192A1 - Dispositif de calcul de résistance interne, programme informatique et procédé de calcul de résistance interne - Google Patents

Dispositif de calcul de résistance interne, programme informatique et procédé de calcul de résistance interne Download PDF

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Publication number
WO2017047192A1
WO2017047192A1 PCT/JP2016/068651 JP2016068651W WO2017047192A1 WO 2017047192 A1 WO2017047192 A1 WO 2017047192A1 JP 2016068651 W JP2016068651 W JP 2016068651W WO 2017047192 A1 WO2017047192 A1 WO 2017047192A1
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Prior art keywords
secondary battery
current
internal resistance
unit
switching
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PCT/JP2016/068651
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English (en)
Japanese (ja)
Inventor
裕章 武智
智美 片岡
洋平 山口
碧 畑中
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住友電気工業株式会社
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Priority claimed from JP2016083939A external-priority patent/JP6614007B2/ja
Application filed by 住友電気工業株式会社 filed Critical 住友電気工業株式会社
Priority to EP16846065.7A priority Critical patent/EP3351945B1/fr
Priority to US15/760,518 priority patent/US10656213B2/en
Priority to CN201680053573.8A priority patent/CN108027396B/zh
Publication of WO2017047192A1 publication Critical patent/WO2017047192A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]

Definitions

  • the present invention relates to an internal resistance calculation device, a computer program, and an internal resistance calculation method.
  • This application includes Japanese application No. 2015-185635 filed on Sep. 18, 2015, Japanese application No. 2016-001983 filed on Jan. 7, 2016, and Japanese application No. 2016-044721 filed on Mar. 8, 2016. No., Japanese Patent Application No. 2016-083939 filed on Apr. 19, 2016, and uses all the contents described in the Japanese application.
  • HEV Hybrid Electric Vehicle
  • EV Electric Vehicle
  • HEV and EV are equipped with secondary batteries.
  • HEV drives a vehicle by driving a motor using electric power stored in a secondary battery or performs engine assist. For this reason, in HEV, switching between charging and discharging of the secondary battery is repeated with frequency as the vehicle travels.
  • overdischarge or overcharge is performed, the secondary battery is deteriorated. Therefore, it is necessary to control charge / discharge while grasping the charge amount of the secondary battery.
  • An internal resistance calculation device of the present disclosure is an internal resistance calculation device that calculates an internal resistance of a secondary battery, and includes a voltage acquisition unit that acquires a voltage of the secondary battery, and a current acquisition that acquires a current of the secondary battery. And a switching determination unit that determines whether or not to switch charging / discharging of the secondary battery based on the current acquired by the current acquisition unit, and a predetermined ion diffusion process in the impedance spectrum of the secondary battery.
  • the specific part that specifies the standby time based on the boundary frequency range in which the resulting diffusion impedance contributes to the impedance of the secondary battery, and the specific part specified when the switching determination part determines that there is charge / discharge switching A resistance calculation unit that calculates an internal resistance of the secondary battery based on the voltage acquired by the voltage acquisition unit after the standby time and the current acquired by the current acquisition unit.
  • a computer program of the present disclosure is a computer program for causing a computer to calculate an internal resistance of a secondary battery, the computer including a voltage acquisition unit that acquires a voltage of the secondary battery, and a current of the secondary battery. Due to the diffusion process of predetermined ions in the current acquisition unit to be acquired, the switching determination unit for determining whether the secondary battery is switched between charge and discharge based on the acquired current, and the impedance spectrum of the secondary battery When the determination unit determines that there is a switching between charging and discharging of the secondary battery based on the boundary frequency range in which the diffusion impedance that contributes to the impedance of the secondary battery determines the standby time, the acquired after the specified standby time It functions as a resistance calculator that calculates the internal resistance of the secondary battery based on voltage and current.
  • the internal resistance calculation method of the present disclosure is an internal resistance calculation method for calculating an internal resistance of a secondary battery, wherein a voltage acquisition unit acquires a voltage of the secondary battery, and a current acquisition unit acquires a current of the secondary battery.
  • the switching determination unit determines whether the secondary battery is switched between charge and discharge based on the acquired current, and the diffusion impedance resulting from the diffusion process of predetermined ions in the impedance spectrum of the secondary battery Is acquired after the specified standby time when the specifying unit specifies the standby time based on the boundary frequency region that contributes to the impedance of the secondary battery, and it is determined that there is charge / discharge switching of the secondary battery
  • a resistance calculation unit calculates the internal resistance of the secondary battery based on the voltage and current.
  • An object of the present invention is to provide a computer program and an internal resistance calculation method.
  • the internal resistance calculation device is an internal resistance calculation device that calculates the internal resistance of a secondary battery, and acquires a voltage of a secondary battery and a current of the secondary battery.
  • the current acquisition unit a switching determination unit that determines whether or not to switch charging / discharging of the secondary battery based on the current acquired by the current acquisition unit, and an impedance spectrum of the secondary battery.
  • a specific unit that specifies a standby time based on a boundary frequency region in which a diffusion impedance caused by a diffusion process contributes to the impedance of the secondary battery, and the determination unit when the switching determination unit determines that there is a charge / discharge switching.
  • a resistance calculation unit that calculates an internal resistance of the secondary battery based on the voltage acquired by the voltage acquisition unit and the current acquired by the current acquisition unit after the standby time specified in (1).
  • a computer program is a computer program for causing a computer to calculate an internal resistance of a secondary battery, the computer acquiring a voltage of a secondary battery, and the secondary battery
  • a current acquisition unit that acquires the current of the secondary battery
  • a switching determination unit that determines whether charging / discharging of the secondary battery is switched based on the acquired current, and diffusion of predetermined ions in the impedance spectrum of the secondary battery
  • the specific part that specifies the standby time based on the boundary frequency region in which the diffusion impedance resulting from the process contributes to the impedance of the secondary battery, the specified standby time It is made to function as a resistance calculation part which calculates the internal resistance of the said secondary battery based on the voltage and electric current which were acquired later.
  • the internal resistance calculation method is an internal resistance calculation method for calculating the internal resistance of a secondary battery, wherein the voltage acquisition unit acquires the voltage of the secondary battery, and the current of the secondary battery is the current.
  • the acquisition unit acquires and the switching determination unit determines whether the secondary battery is switched between charge and discharge based on the acquired current, and is caused by a predetermined ion diffusion process in the impedance spectrum of the secondary battery.
  • the identification unit identifies the standby time based on the boundary frequency region in which the diffusion impedance that contributes to the impedance of the secondary battery and it is determined that charging / discharging of the secondary battery is switched, after the identified standby time
  • a resistance calculation unit calculates an internal resistance of the secondary battery based on the acquired voltage and current.
  • the voltage acquisition unit acquires the voltage of the secondary battery, and the current acquisition unit acquires the current (charging current or discharging current) of the secondary battery.
  • the switching determination unit determines whether charging / discharging of the secondary battery is switched based on the current acquired by the current acquisition unit. For example, when either charge or discharge is defined as positive and the current changes from positive to negative or 0, the current changes from 0 to positive or negative, or the current changes from negative to positive or 0 It can be determined that there has been switching between charge and discharge.
  • the identifying unit identifies the standby time based on the boundary frequency region where the diffusion impedance resulting from the diffusion process of predetermined ions contributes to the impedance of the secondary battery in the impedance spectrum of the secondary battery.
  • the impedance spectrum is also called a Cole-Cole plot or a Nyquist plot, and is a plot of values obtained by measuring the impedance of the secondary battery at a plurality of frequencies using the AC impedance method.
  • the secondary battery can be expressed by an equivalent circuit including an electrolyte bulk resistance Rs, an interface charge transfer resistance Rc, an electric double layer capacitance C, and a diffusion impedance Zw.
  • the internal resistance of the secondary battery is mainly composed of the electrolyte bulk resistance Rs and the interface charge transfer resistance Rc.
  • the diffusion impedance Zw increases in a certain frequency range (referred to as a boundary frequency range), and the impedance of the secondary battery increases (secondary Contributes to battery impedance). Therefore, it can be said that the impedance in the boundary frequency region before the diffusion impedance Zw increases represents the internal resistance of the secondary battery.
  • the relationship T 1 / (2 ⁇ f) between the frequency f in the AC impedance method and the standby time T from when the direct current is applied to the measurement, that is, the standby time T is, for example, the frequency f It can be specified from the relationship of the reciprocal of twice. For example, when the frequency f is 5 Hz, the standby time T is 0.1 second. Note that the standby time T is an inverse of twice the frequency f is an example. For example, the standby time T may be an inverse of four times the frequency f.
  • the resistance calculation unit determines whether the internal voltage of the secondary battery is based on the voltage acquired by the voltage acquisition unit after the standby time specified by the specification unit and the current acquired by the current acquisition unit. Calculate the resistance.
  • the diffusion resistance diffusion impedance
  • the charge transfer resistance among the internal resistances of the secondary battery are once reset, and the internal resistance starts to increase according to the energization time. Therefore, when it is determined that charging / discharging is switched, the internal resistance of the secondary battery can be calculated by obtaining the voltage Vc and the current Ic after the standby time T.
  • the resistance calculation unit includes the voltage acquired by the voltage acquisition unit and the current acquired by the current acquisition unit before the switching determination unit determines that there is charge / discharge switching.
  • the internal resistance of the secondary battery is calculated based on the voltage acquired by the voltage acquisition unit and the current acquired by the current acquisition unit after the standby time specified by the specifying unit.
  • the resistance calculation unit includes the voltage Vb acquired by the voltage acquisition unit and the current Ib acquired by the current acquisition unit before the switching determination unit determines that there is charge / discharge switching, and the voltage acquisition unit after the standby time T specified by the specification unit.
  • the internal resistance R of the secondary battery is calculated based on the voltage Vc acquired in step 1 and the current Ic acquired by the current acquisition unit.
  • the resistance calculation unit has an internal resistance of the secondary battery when the current acquired by the current acquisition unit is greater than a predetermined threshold after the standby time specified by the specification unit. Is calculated.
  • the resistance calculation unit calculates the internal resistance of the secondary battery when the current acquired by the current acquisition unit is greater than a predetermined threshold after the standby time T specified by the specification unit.
  • a predetermined threshold after the standby time T specified by the specification unit.
  • the internal resistance calculation device is based on the current acquired by the current acquisition unit, and the standby time specified by the specifying unit elapses from the time when the switching determination unit determines that there is charge / discharge switching.
  • a current integrated value calculating unit that calculates a current integrated value until the current integrated value calculated by the current integrated value calculating unit is greater than a predetermined lower limit value. Calculate internal resistance.
  • the current integrated value calculation unit is based on the current acquired by the current acquisition unit, and is the current integrated value from the time when the switching determination unit determines that charging / discharging is switched until the standby time T specified by the specifying unit elapses Is calculated.
  • the “determined time point” can be the next sampling time point after switching between charge and discharge. For example, if the time point at which charging / discharging switching occurs is t2, the first sampling time point after time t2 is t3, and the time point when the standby time T elapses from time point t3 (may be time point t2) is t4, It can be calculated based on the total value of the current values sampled between t3 and time t4.
  • the resistance calculation unit calculates the internal resistance of the secondary battery when the current integration value calculated by the current integration value calculation unit is larger than a predetermined lower limit value.
  • the predetermined lower limit value can be calculated by, for example, predetermined threshold value Ith ⁇ standby time T ⁇ required coefficient ⁇ ( ⁇ is, for example, 0.5 ⁇ ⁇ ).
  • the predetermined threshold Ith is a threshold used when determining whether or not to calculate the internal resistance of the secondary battery based on the current after the elapse of the standby time T.
  • the current value of the secondary battery changes at a relatively small value, and if the predetermined threshold value Ith is exceeded immediately before the standby time T elapses, the current of the secondary battery is sufficiently stabilized. There are cases where it cannot be said that a state has been reached. Therefore, by providing a condition that the current integrated value from the switching of charging / discharging until the standby time T elapses is larger than a predetermined lower limit value, the current value of the secondary battery changes at a relatively small value, and the standby time It is possible to eliminate a state that is not a sufficiently stable state that increases immediately before the elapse of T, and it is possible to further improve the calculation accuracy of the internal resistance.
  • the internal resistance calculation device is based on the current acquired by the current acquisition unit, and the standby time specified by the specifying unit elapses from the time when the switching determination unit determines that there is charge / discharge switching.
  • a current integrated value calculation unit that calculates a current integrated value after switching between the time point until and a current integrated value before switching from the time point before switching before the standby time before the time point to the time point, the resistance calculating unit Calculates the internal resistance of the secondary battery when the difference between the integrated current value after switching and the integrated current value before switching is equal to or less than a predetermined difference threshold value.
  • the integrated current value calculation unit determines the current after switching from the time when the switching determination unit determines that charging / discharging is switched until the standby time T specified by the specifying unit elapses.
  • the integrated value and the integrated current value before switching from the pre-switching time point before the standby time T before the determined time point to the determined time point are calculated.
  • the “determined time point” can be the next sampling time point after switching between charge and discharge. For example, t2 is the time when charging / discharging switching occurs, t3 is the first sampling time after time t2, t4 is the time when standby time T has elapsed from time t3 (may be time t2), and t3 is time (may be time t2).
  • the post-switching current integrated value can be calculated based on the total value of the current values sampled from the time point t3 to the time point t4.
  • the integrated value can be calculated based on the total value of the current values sampled between time t1 and time (t3-1).
  • the time point (t3-1) is the sampling time point one time before the sampling time point t3.
  • the resistance calculation unit calculates the internal resistance of the secondary battery when the difference between the integrated current value after switching and the integrated current value before switching is equal to or less than a predetermined difference threshold value.
  • the predetermined difference threshold value can be calculated by, for example, a predetermined threshold value Ith ⁇ standby time T ⁇ required coefficient ⁇ ( ⁇ is, for example, 0.1 ⁇ ⁇ ⁇ 2).
  • the predetermined threshold Ith is a threshold used when determining whether or not to calculate the internal resistance of the secondary battery based on the current after the elapse of the standby time T.
  • the current value of the secondary battery changes relatively stably, and even when the current after the standby time T is greater than the predetermined threshold Ith, the current of the secondary battery before switching charging / discharging
  • the state of charge transfer of the secondary battery may be different before and after switching between charge and discharge. Therefore, by providing a condition that the difference between the integrated current values before and after charging / discharging is less than or equal to a predetermined difference threshold, there is a tendency for charge transfer so that the difference between the current values of the secondary battery before and after charging / discharging becomes large. Different states can be eliminated, and the calculation accuracy of the internal resistance can be further improved.
  • the time when the resistance calculation unit determines that the charge / discharge switching is performed by the switching determination unit is within a predetermined time from the time when the charge / discharge switching is most recently determined. In some cases, the internal resistance of the secondary battery is not calculated.
  • the resistance calculation unit does not calculate the internal resistance of the secondary battery when the switching determination unit determines that the charge / discharge switching is within a predetermined time from the most recent determination that the charge / discharge switching has occurred.
  • the predetermined time can be, for example, 50 ms, but is not limited thereto.
  • the charging / discharging current is switched so that the charging current flows when the charging current flows, the discharging current flows and the charging current flows within a predetermined time (within a relatively short time).
  • the internal resistance calculation device includes a current change degree calculation unit that calculates the degree of change in current based on the current acquired by the current acquisition unit, and the resistance calculation unit is the switching determination unit.
  • the degree of change calculated by the current change degree calculation unit is greater than a predetermined change degree threshold between the time when it is determined that there is charge / discharge switching and the standby time specified by the specifying unit elapses, the secondary Do not calculate battery internal resistance.
  • the current change degree calculation unit calculates the current change degree based on the current acquired by the current acquisition unit. For example, when acquiring a current at a predetermined sampling period, if the difference between the current acquired at the current sampling time and the current acquired at the most recent (previous) sampling time is ⁇ I and the sampling interval is ⁇ ts, the current The degree of change can be calculated by, for example, an equation ⁇ I / ⁇ ts.
  • the resistance calculation unit determines that the change degree calculated by the current change degree calculation unit is a predetermined change degree from the time when the switching determination part determines that charging / discharging is switched until the standby time T specified by the specifying part elapses.
  • the internal resistance of the secondary battery is not calculated. For example, if t2 is the time when charging / discharging switching occurs and t4 is the time when the standby time T elapses, the degree of change in current based on the current sampled and acquired between time t2 and time t4 is a predetermined change.
  • the degree threshold the internal resistance of the secondary battery is not calculated.
  • the specifying unit further specifies a standby time based on the charging rate of the secondary battery.
  • the specifying unit further specifies the standby time based on the charging rate (SOC) of the secondary battery.
  • SOC charging rate
  • the internal resistance calculation device includes a temperature acquisition unit that acquires the temperature of the secondary battery, and the specification unit further specifies a standby time based on the temperature acquired by the temperature acquisition unit. .
  • the temperature acquisition unit acquires the temperature of the secondary battery.
  • the specifying unit further specifies the standby time based on the temperature acquired by the temperature acquisition unit.
  • the lower the temperature of the secondary battery the smaller the boundary frequency region, and the standby time T inversely proportional to the frequency f in the boundary frequency region increases. Therefore, for example, a correction coefficient K2 corresponding to the temperature of the secondary battery is determined, and the standby time is corrected according to the temperature of the secondary battery to specify the final standby time.
  • the internal resistance can be accurately calculated regardless of the temperature of the secondary battery.
  • the internal resistance calculation device is based on the internal resistance calculated by the resistance calculation unit, the voltage acquired by the voltage acquisition unit, and the current acquired by the current acquisition unit.
  • Vo is an overvoltage, which is a voltage obtained by adding a polarization voltage to the voltage represented by the internal resistance R ⁇ current I.
  • the charging rate calculation unit calculates the charging rate of the secondary battery based on the open circuit voltage calculated by the open circuit voltage calculation unit. For example, the charging rate of the secondary battery can be calculated based on the calculated opening voltage by predetermining the correlation between the opening voltage OCV and the charging rate (SOC) of the secondary battery.
  • the internal resistance calculation device calculates the deterioration level of the secondary battery based on the ratio of the internal resistance calculated by the resistance calculation unit to the initial value of the internal resistance of the secondary battery. A part.
  • the deterioration degree calculation unit calculates the deterioration degree (SOH) of the secondary battery based on the ratio of the internal resistance R calculated by the resistance calculation unit with respect to the initial value R0 of the internal resistance of the secondary battery.
  • a correlation between the increase rate of the internal resistance and the discharge capacity ratio (deterioration degree) is determined in advance, and the deterioration degree (SOH) is calculated by specifying the discharge capacity ratio corresponding to the ratio R / R0 of the internal resistance. be able to.
  • FIG. 1 is a block diagram showing an example of a configuration of a main part of a vehicle equipped with a battery monitoring device 100 as an internal resistance calculation device of the present embodiment.
  • the vehicle includes a secondary battery unit 50, relays 61 and 63, a generator (ALT) 62, a starter motor (ST) 64, a battery 65, an electric load 66, and the like. Is provided.
  • the secondary battery unit 50 is, for example, a lithium ion battery, and a plurality of cells 51 are connected in series or in series-parallel.
  • the secondary battery unit 50 includes a voltage sensor 52, a current sensor 53, and a temperature sensor 54.
  • the voltage sensor 52 detects the voltage of each cell 51 and the voltage at both ends of the secondary battery unit 50, and outputs the detected voltage to the battery monitoring device 100 via the voltage detection line 50a.
  • the current sensor 53 is composed of, for example, a shunt resistor or a hall sensor, and detects the charging current and discharging current of the secondary battery.
  • the current sensor 53 outputs the current detected via the current detection line 50b to the battery monitoring device 100.
  • the temperature sensor 54 is composed of, for example, a thermistor, and detects the temperature of the cell 51.
  • the temperature sensor 54 outputs the temperature detected via the temperature detection line 50c to the battery monitoring device 100.
  • the battery 65 is, for example, a lead battery, and supplies power to the electric load 66 of the vehicle and supplies power for driving the starter motor 64 when the relay 63 is turned on.
  • the generator 62 generates electricity by the rotation of the engine of the vehicle, and outputs a direct current by a rectifier circuit provided inside to charge the battery 65.
  • the generator 62 charges the battery 65 and the secondary battery unit 50 when the relay 61 is on.
  • the relays 61 and 63 are turned on / off by a relay control unit (not shown).
  • FIG. 2 is a block diagram showing an example of the configuration of the battery monitoring device 100 as the internal resistance calculation device of the present embodiment.
  • the battery monitoring apparatus 100 includes a control unit 10, a voltage acquisition unit 11, a current acquisition unit 12, a temperature acquisition unit 13, a switching determination unit 14, a standby time identification unit 15, a resistance calculation unit 16, and an open voltage calculation unit that control the entire apparatus. 17, a charging rate calculation unit 18, a deterioration degree calculation unit 19, a storage unit 20, a timer 21 for timing, and the like.
  • the voltage acquisition unit 11 acquires the voltage of the secondary battery unit 50 (for example, the voltage across the secondary battery unit 50). Further, the current acquisition unit 12 acquires the current (charging current and discharging current) of the secondary battery unit 50.
  • the control part 10 can control the acquisition frequency of a voltage and an electric current, and the sampling period to acquire.
  • the switching determination unit 14 determines whether charging / discharging of the secondary battery unit 50 is switched based on the current acquired by the current acquisition unit 12. For example, if the current acquired by the current acquisition unit 12 in the case of charging is defined as positive, the direction of the current is opposite between charging and discharging, so when the current acquired by the current acquisition unit 12 is negative, It can be determined that this is a discharge. That is, when either charge or discharge is determined as positive and the current changes from positive to negative or 0, the current changes from 0 to positive or negative, or the current changes from negative to positive or 0 It can be determined that there has been switching between charge and discharge.
  • the standby time specifying unit 15 has a function as a specifying unit, and in the impedance spectrum of the secondary battery unit 50, the boundary where the diffusion impedance resulting from the diffusion process of predetermined ions contributes to the impedance of the secondary battery unit 50
  • the waiting time is specified based on the frequency range.
  • the impedance spectrum is also called a Cole-Cole plot or a Nyquist plot, and is a plot of values obtained by measuring the impedance of the secondary battery unit 50 at a plurality of frequencies using the AC impedance method.
  • the predetermined ion is a lithium (Li) ion.
  • the boundary frequency range means that the frequency has a required width, and means that the frequency is not limited to a single frequency.
  • FIG. 3 is an explanatory diagram showing an example of an equivalent circuit of the secondary battery unit 50 of the present embodiment.
  • the secondary battery unit 50 can be represented by an equivalent circuit including an electrolyte bulk resistance Rs, an interface charge transfer resistance Rc, an electric double layer capacitance C, and a diffusion impedance Zw. More specifically, the impedance of the secondary battery unit 50 is obtained by connecting a resistance Rs of an electrolyte bulk in series to a circuit in which an electric double layer capacitance C is connected in parallel to a series circuit of an interface charge transfer resistance Rc and a diffusion impedance Zw. It can be represented equivalently by a connected circuit.
  • the resistance Rs of the electrolytic solution bulk includes the conduction resistance of lithium (Li) ions in the electrolytic solution, the electronic resistance at the positive electrode and the negative electrode, and the like.
  • the interface charge transfer resistance Rc includes a charge transfer resistance and a film resistance on the surface of the active material.
  • the diffusion impedance Zw is an impedance resulting from the diffusion process of lithium (Li) ions into the active material particles.
  • FIG. 4 is an explanatory diagram showing an example of the impedance spectrum of the secondary battery unit 50 of the present embodiment.
  • the horizontal axis represents the real component Zr of the impedance Z
  • the vertical axis represents the imaginary component Zi of the impedance Z.
  • the internal resistance of the secondary battery unit 50 is mainly composed of an electrolyte bulk resistance Rs and an interface charge transfer resistance Rc.
  • the frequency in the AC impedance method is changed from a high frequency to a low frequency (for example, 100 kHz to 0.01 mHz, or 1 MHz to 10 ⁇ Hz, etc.), as shown in FIG.
  • the diffusion impedance Zw increases, and the impedance of the secondary battery unit 50 increases (contributes to the impedance of the secondary battery). That is, in the impedance spectrum of the secondary battery unit 50, the diffusion impedance resulting from the diffusion process of predetermined ions contributes to the impedance of the secondary battery unit 50.
  • the frequency (or angular frequency) is changed from a high frequency to a low frequency.
  • the diffusion impedance Zw increases, which means that the impedance of the secondary battery unit 50 increases.
  • the impedance of the secondary battery unit 50 can be represented by the total value of the resistance Rs of the electrolyte solution bulk and the interface charge transfer resistance Rc, and the influence (contribution) due to the diffusion impedance Zw is small or negligible. It means the frequency range where it can be done.
  • an AC voltage whose frequency is changed to specify each element of the equivalent circuit of the secondary battery unit 50 is applied to the secondary battery unit 50, and a current signal obtained from the secondary battery unit 50 is obtained.
  • the impedance is obtained by converting the voltage signal into the frequency domain by discrete Fourier transform.
  • the impedance Z of the secondary battery unit 50 can be expressed by Expression (1).
  • w is an angular frequency
  • ⁇ is a constant related to the diffusion condition.
  • the impedance spectrum shown in FIG. 4 is obtained by plotting the impedance represented by Equation (1) for each frequency.
  • the real component Zr of the impedance Z in the equation (1) can be expressed by the equation (2), and the imaginary component Zi can be expressed by the equation (3).
  • Equation (4) and Equation (5) when w is eliminated from the equations (4) and (5), the equation (6) is obtained.
  • equation (7) is obtained.
  • the internal resistance R of the secondary battery unit 50 is mainly composed of the electrolyte bulk resistance Rs and the interface charge transfer resistance Rc. Further, when the frequency in the AC impedance method is changed from a high frequency to a low frequency, the diffusion impedance Zw increases in the boundary frequency region, and the impedance of the secondary battery increases (contributes to the impedance of the secondary battery). . Therefore, it can be said that the impedance Z in the boundary frequency region before the diffusion impedance Zw increases represents the internal resistance R of the secondary battery unit 50.
  • the standby time T can be specified from the relationship of the reciprocal of twice the frequency f, for example. For example, when the frequency f is 5 Hz, the standby time T is 0.1 second. Note that the standby time T is an inverse of twice the frequency f is an example. For example, the standby time T may be an inverse of four times the frequency f.
  • the resistance calculation unit 16 acquires the voltage acquired by the voltage acquisition unit 11 and the current acquired by the current acquisition unit 12 after the standby time T specified by the standby time specification unit 15. Based on the above, the internal resistance R of the secondary battery unit 50 is calculated.
  • the internal resistance R of the secondary battery unit 50 When switching from charge to discharge, or from discharge to charge, among the internal resistance R of the secondary battery unit 50, for example, the diffusion resistance (diffusion impedance) and the charge transfer resistance are reset once, and the internal resistance R changes depending on the energization time. Start to increase. Therefore, when it is determined that charging / discharging is switched, the internal resistance R of the secondary battery unit 50 can be calculated by obtaining the voltage Vc and the current Ic after the standby time T. Thus, since the internal resistance R can be obtained in a short time (for example, about 0.1 second) after switching between charging and discharging, even when charging and discharging are repeated frequently, a relatively short time after switching between charging and discharging. Thus, the internal resistance R of the secondary battery unit 50 can be accurately calculated.
  • the resistance calculation unit 16 determines the voltage Vb acquired by the voltage acquisition unit 11 and the current Ib acquired by the current acquisition unit 12 and the standby time before determining that the switching determination unit 14 has switching between charge and discharge.
  • the internal resistance R of the secondary battery is calculated based on the voltage Vc acquired by the voltage acquisition unit 11 and the current Ic acquired by the current acquisition unit 12 after the standby time T specified by the specification unit 15.
  • the internal resistance of the secondary battery can be calculated with high accuracy.
  • the resistance calculation unit 16 calculates the internal resistance R of the secondary battery unit 50 when the current acquired by the current acquisition unit 12 is greater than a predetermined threshold after the standby time T specified by the standby time specification unit 15.
  • the internal resistance R cannot be calculated with high accuracy. Therefore, by adding the condition that the current is greater than a predetermined threshold value, the calculation accuracy of the internal resistance R is calculated. Can be raised.
  • FIG. 5 is an explanatory diagram showing an example of an impedance spectrum when the charging rate of the secondary battery unit 50 of the present embodiment is changed.
  • the example of FIG. 5 shows an impedance spectrum when the charging rate (SOC: State of Charge) is changed to 20%, 50%, and 80% at 25 ° C.
  • SOC State of Charge
  • the boundary frequency region changes to 2.5 Hz, 4.0 Hz, and 6.3 Hz.
  • the standby times T corresponding to the boundary frequency ranges 2.5 Hz, 4.0 Hz, and 6.3 Hz are 0.2 seconds, 0.125 seconds, and 0.079 seconds, respectively.
  • FIG. 6 is an explanatory diagram showing an example of an impedance spectrum when the temperature of the secondary battery unit 50 of the present embodiment is changed.
  • the example of FIG. 6 shows an impedance spectrum when the charging rate is constant and the temperature of the secondary battery unit 50 is changed to 10 ° C., 25 ° C., and 45 ° C.
  • the boundary frequency region changes to 2 Hz, 7.9 Hz, and 32 Hz.
  • the standby times T corresponding to the boundary frequency ranges 2 Hz, 7.9 Hz, and 32 Hz are 0.25 seconds, 0.063 seconds, and 0.015 seconds, respectively.
  • FIG. 7 is an explanatory diagram showing an example of impedance spectra of new and deteriorated secondary battery units 50 of the present embodiment.
  • the boundary frequency range is 7.94 Hz
  • the boundary frequency range is 3.98 Hz. It can be seen that the impedance of the secondary battery unit 50 increases as the secondary battery 50 deteriorates.
  • the standby times T corresponding to the boundary frequency ranges of 3.98 Hz and 7.94 Hz are 0.126 seconds and 0.063 seconds, respectively.
  • FIG. 8 is an explanatory diagram showing an example of the standby time corresponding to the boundary frequency region of the secondary battery unit 50 of the present embodiment.
  • the boundary frequency range is such that the impedance Z of the secondary battery unit 50 is equal to the diffusion impedance Zw. This is the frequency of the region that begins to increase with an increase.
  • the boundary frequency region can be a frequency region having a width of ⁇ 50% with respect to the reference frequency, for example.
  • the boundary frequency range of 4 Hz may include a frequency range of ⁇ 50% of the reference frequency of 4 Hz.
  • the boundary frequency range of 4 Hz becomes the standby time of 0.125 seconds, and a time of ⁇ 50% centering on 0.125 seconds is set as the standby time T corresponding to the boundary frequency range.
  • the standby time of 0.125 seconds may include a range of 0.0625 seconds to 0.187 seconds.
  • SOC charging rate
  • the standby time specifying unit 15 specifies the standby time based on the charging rate (SOC) of the secondary battery unit 50. As illustrated in FIG. 5, the smaller the charging rate (SOC), the smaller the boundary frequency region, and the standby time T that is inversely proportional to the frequency f in the boundary frequency region increases.
  • the correction coefficient K0 corresponding to the charging rate may be stored in the storage unit 20, or may be calculated by an arithmetic circuit.
  • the temperature acquisition unit 13 acquires the temperature of the secondary battery unit 50.
  • the standby time specifying unit 15 specifies the standby time T based on the temperature acquired by the temperature acquisition unit 13. As illustrated in FIG. 6, the lower the temperature of the secondary battery unit 50, the smaller the boundary frequency region, and the standby time T that is inversely proportional to the frequency f in the boundary frequency region increases.
  • the final standby time T K1 ⁇ T0. Calculate with the formula. Accordingly, the final standby time T can be specified by correcting the standby time according to the temperature of the secondary battery unit 50, so that the internal resistance R is accurately calculated regardless of the temperature of the secondary battery unit 50. can do.
  • the correction coefficient K1 corresponding to the temperature may be stored in the storage unit 20, or may be calculated by an arithmetic circuit.
  • the standby time specifying unit 15 can specify the standby time T based on the degree of deterioration of the secondary battery unit 50. As illustrated in FIG. 7, as the deterioration of the secondary battery unit 50 progresses, the boundary frequency region decreases, and the standby time T that is inversely proportional to the frequency f in the boundary frequency region increases.
  • the correction coefficient K2 corresponding to the deterioration may be stored in the storage unit 20, or may be calculated by an arithmetic circuit.
  • Vo is an overvoltage, which is a voltage obtained by adding a polarization voltage to the voltage represented by the internal resistance R ⁇ current I.
  • FIG. 9 is an explanatory diagram showing an example of the correlation between the open circuit voltage and the charging rate of the secondary battery unit 50 of the present embodiment.
  • the horizontal axis indicates the open circuit voltage (OCV), and the vertical axis indicates the charging rate (SOC).
  • OCV open circuit voltage
  • SOC charging rate
  • the charging rate increases as the open circuit voltage of the secondary battery unit 50 increases.
  • the correlation between the open circuit voltage and the charging rate illustrated in FIG. 9 may be stored in the storage unit 20 or may be calculated by an arithmetic circuit.
  • the charging rate calculation unit 18 calculates the charging rate of the secondary battery unit 50 based on the open circuit voltage calculated by the open circuit voltage calculation unit 17. As described above, the charging rate of the secondary battery unit 50 is calculated based on the calculated opening voltage by predetermining the correlation between the opening voltage OCV of the secondary battery unit 50 and the charging rate (SOC). be able to.
  • the deterioration degree calculation unit 19 calculates the deterioration degree (SOH) of the secondary battery based on the ratio of the internal resistance R calculated by the resistance calculation unit 16 with respect to the initial value R0 of the internal resistance of the secondary battery unit 50.
  • FIG. 10 is an explanatory diagram showing an example of a correlation between the internal resistance increase rate and the discharge capacity ratio of the secondary battery unit 50 of the present embodiment.
  • the horizontal axis represents the internal resistance increase rate
  • the vertical axis represents the discharge capacity ratio.
  • the temperature is 25 ° C. and the charging rate is 50%.
  • the capacity reduction of the secondary battery unit 50 has a correlation with the deterioration.
  • the discharge capacity ratio is 1, the degree of deterioration can be 0, and the degree of deterioration increases as the discharge capacity ratio decreases.
  • the discharge capacity ratio decreases as the internal resistance increase rate of the secondary battery unit 50 increases, and the degree of degradation (SOH) increases.
  • the correlation between the internal resistance increase rate and the discharge capacity ratio illustrated in FIG. 10 may be stored in the storage unit 20 or may be calculated by an arithmetic circuit.
  • the correlation between the increasing rate of the internal resistance R and the discharge capacity ratio (degradation degree) is determined in advance, and the discharge capacity ratio corresponding to the ratio R / R0 of the internal resistance is specified. (SOH) can be calculated.
  • FIG. 11 is a flowchart illustrating an example of a processing procedure of the battery monitoring apparatus 100 according to the present embodiment.
  • the processing subject will be described as the control unit 10.
  • the control unit 10 performs an internal resistance calculation process (S11). Details of the internal resistance calculation process will be described later.
  • the control unit 10 determines the presence / absence of the calculation result of the internal resistance (S12), and if there is no calculation result of the internal resistance (NO in S12), the process of step S11 is continued. When there is a calculation result of the internal resistance (YES in S12), the control unit 10 performs a charging rate calculation process (S13) and performs a deterioration degree calculation process (S14). Details of the charging rate calculation process and the deterioration degree calculation process will be described later.
  • FIG. 12 is a flowchart showing an example of the procedure of the internal resistance calculation process of the battery monitoring apparatus 100 of the present embodiment.
  • the control unit 10 acquires the voltage of the secondary battery (S51), and acquires the current of the secondary battery (S52).
  • the control part 10 determines the presence or absence of switching of charging / discharging based on the acquired electric current (S53). The determination of whether charging / discharging is switched can be performed as follows.
  • the third condition is that the current value ⁇ 0 acquired most recently (previous) and the current current value ⁇ is any one of the first to third conditions.
  • control unit 10 If there is no charge / discharge switching (NO in S53), the control unit 10 continues the processing from step S51. When the charge / discharge switching is performed (YES in S53), the control unit 10 stores the voltage Vb and current Ib acquired immediately before the charge / discharge switching in the storage unit 20 (S54).
  • the control unit 10 performs a standby time specifying process (S55). Details of the waiting time specifying process will be described later.
  • the control unit 10 measures time (S56). Note that the time measurement start time may be the time when it is determined that the charge / discharge switching is performed (the time when the above-described current voltage or current is acquired), or the time when the most recent (previous) voltage or current is acquired.
  • the control unit 10 determines whether or not the standby time has elapsed (S57). If the standby time has not elapsed (NO in S57), the processing from step S56 is continued.
  • the control unit 10 acquires the voltage Vc of the secondary battery (S58), and acquires the current Ic of the secondary battery (S59).
  • the control unit 10 determines whether or not the acquired current Ic is greater than or equal to a predetermined threshold (S60).
  • the threshold value can be set to a value necessary for accurately calculating the internal resistance.
  • the control unit 10 calculates the internal resistance (S61) and ends the process.
  • the control unit 10 ends the process without performing the process of step S61.
  • FIG. 13 is a flowchart showing an example of the procedure of the standby time specifying process of the battery monitoring apparatus 100 of the present embodiment.
  • the control unit 10 acquires the standby time according to the charging rate of the secondary battery (S101), acquires the correction coefficient K1 according to the temperature (cell temperature) of the secondary battery (S102), and deteriorates the secondary battery.
  • a correction coefficient K2 corresponding to the degree is acquired (S103).
  • the control unit 10 specifies the final standby time T by multiplying the standby time (for example, the standby time initial value T0) obtained in step S101 according to the charging rate of the secondary battery by each correction coefficient (S104). ), The process is terminated.
  • the correction coefficient K1 or K2 may be multiplied by the standby time initial value T0.
  • FIG. 14 is a flowchart showing an example of the procedure of the charging rate calculation process of the battery monitoring apparatus 100 of the present embodiment.
  • the control unit 10 acquires the voltage V of the secondary battery (S121), and acquires the current I of the secondary battery (S122).
  • the control unit 10 calculates the open circuit voltage using the calculated internal resistance R (S123).
  • OCV OCV
  • V ⁇ Vo V ⁇ Vo.
  • Vo is an overvoltage, which is a voltage obtained by adding a polarization voltage to the voltage represented by the internal resistance R ⁇ current I.
  • the control unit 10 calculates the charging rate based on the calculated open circuit voltage (S124), and ends the process.
  • FIG. 15 is a flowchart showing an example of the procedure of the deterioration degree calculation process of the battery monitoring apparatus 100 of the present embodiment.
  • the control unit 10 calculates the internal resistance correction value Rn from the calculated internal resistance R (S141).
  • the internal resistance correction value Rn is a value obtained by converting the calculated internal resistance R into, for example, a value when the charging rate is 50% and the temperature of the secondary battery is 25 ° C.
  • the control unit 10 calculates the increase rate of the internal resistance (S142).
  • the increase rate of the internal resistance can be calculated by Rn / R0.
  • the control unit 10 calculates the degree of deterioration based on the calculated internal resistance increase rate (S143), and ends the process.
  • FIG. 16 is a block diagram illustrating an example of the configuration of the battery monitoring device 120 according to the second embodiment. A difference from the configuration of the battery monitoring apparatus 100 of the first embodiment shown in FIG. 2 is that a current integrated value calculation unit 22 is provided. Hereinafter, the battery monitoring apparatus 120 of 2nd Embodiment is demonstrated. The description of the same parts as those in the first embodiment is omitted.
  • the resistance calculation unit 16 determines the internal resistance R of the secondary battery unit 50 when the current acquired by the current acquisition unit 12 after the standby time T specified by the standby time specification unit 15 is greater than a predetermined threshold. Is calculated.
  • a method for calculating the internal resistance R of the secondary battery unit 50 with higher accuracy will be described.
  • FIG. 17 is a schematic diagram showing a first example of the transition of current before and after the charge / discharge switching of the secondary battery unit 50.
  • the vertical axis represents current, and the positive side is charged and the negative side is discharged.
  • the horizontal axis indicates time.
  • the current of the secondary battery unit 50 at the time when the standby time T elapses from the charging / discharging switching time can be a predetermined threshold Ith (for example, about 10 A, but is limited to 10 A). Is not)) or more.
  • the current value of the secondary battery unit 50 changes at a relatively small value, and when the predetermined threshold value Ith is exceeded immediately before the standby time T elapses, the secondary battery unit 50 In some cases, it cannot be said that the current is sufficiently stable.
  • the current after the charge / discharge switching changes below the threshold value Ith in most of the standby time T.
  • a plurality of locations where the current value of the secondary battery unit 50 is lower than the threshold value Ith are included between the charging / discharging switching time and the standby time T.
  • FIG. 18 is an explanatory diagram showing a first example of internal resistance calculation conditions by the battery monitoring device 120 of the second embodiment.
  • the integrated current value calculation unit 22 starts from the time when the switching determination unit 14 determines that charging / discharging is switched until the standby time T specified by the standby time specification unit 15 elapses.
  • the current integrated value during is calculated.
  • the “determined time point” can be the next sampling time point after switching between charge and discharge.
  • the time point at which switching between charge and discharge occurs is t2
  • the first sampling time point after time t2 is t3
  • the waiting time T for example, 0.1 s
  • the current integrated value ⁇ I can be calculated based on the total value of the current values sampled from the time t3 to the time t4.
  • the resistance calculation unit 16 calculates the internal resistance R of the secondary battery unit 50 when the current integration value calculated by the current integration value calculation unit 22 is larger than a predetermined lower limit value (that is, within a predetermined range).
  • the predetermined lower limit value can be calculated by, for example, a predetermined threshold value Ith (for example, 10 A) ⁇ standby time T (for example, 0.1 s) ⁇ required coefficient ⁇ (for example, ⁇ ⁇ 0.5 ⁇ ⁇ ).
  • Ith is a threshold value used when determining whether or not to calculate the internal resistance R of the secondary battery unit 50 based on the current after the elapse of the standby time T.
  • the coefficient ⁇ 1
  • the upper limit need not be set.
  • the predetermined lower limit value can be calculated by, for example, current value I (t4) at standby time T elapsed time ⁇ standby time T ⁇ coefficient p (p is, for example, 0.5 ⁇ p ⁇ 1).
  • the upper limit value can be calculated by, for example, current value I (t4) ⁇ standby time T ⁇ coefficient q (q is, for example, 1 ⁇ q ⁇ 2) when standby time T has elapsed.
  • the resistance calculation unit 16 recharges the secondary battery unit when the current integration value calculated by the current integration value calculation unit 22 is larger than the predetermined lower limit value and smaller than the upper limit value (that is, within the predetermined range).
  • An internal resistance R of 50 is calculated.
  • a lower limit and an upper limit are not limited to the above-mentioned example.
  • the condition that the integrated current value until the standby time T elapses after switching between charge and discharge is within a predetermined range (for example, larger than the lower limit value, larger than the lower limit value, and smaller than the upper limit value).
  • a predetermined range for example, larger than the lower limit value, larger than the lower limit value, and smaller than the upper limit value.
  • FIG. 19 is a schematic diagram showing a second example of the transition of current before and after the charge / discharge switching of the secondary battery unit 50.
  • the vertical axis represents current, and the positive side is charged and the negative side is discharged.
  • the horizontal axis indicates time.
  • the current value of the secondary battery unit 50 changes relatively stably, and the charge / discharge is performed even when the current after the elapse of the standby time T is larger than the predetermined threshold value Ith. In some cases, the current value of the secondary battery unit 50 before the change of the value changes at a large value.
  • the electric current value of the secondary battery unit 50 before charging / discharging switches may change with a small value.
  • the secondary battery unit 50 before the charge / discharge switching is performed.
  • the state of charge transfer of the secondary battery unit 50 may be different before and after switching between charge and discharge.
  • FIG. 20 is an explanatory diagram showing a second example of internal resistance calculation conditions by the battery monitoring device 120 of the second embodiment.
  • the integrated current value calculation unit 22 starts from the time when the switching determination unit 14 determines that charging / discharging is switched until the standby time T specified by the standby time specification unit 15 elapses. And the integrated current value before switching between the pre-switching time point before the standby time T and the determined time point before the determined time point.
  • the “determined time point” can be the next sampling time point after switching between charge and discharge.
  • t2 is a time point at which charging / discharging switching occurs
  • t3 is a first sampling time point after time t2
  • t4 is a time point when a standby time T elapses from time point t3 (may be time point t2).
  • the post-switching current integrated value ⁇ Ia is calculated based on the total value of the current values sampled from the time point t3 to the time point t4. can do.
  • the pre-switching current integrated value ⁇ Ib can be calculated based on the total value of the current values sampled between time t1 and time (t3-1).
  • the time point (t3-1) is the sampling time point one time before the sampling time point t3.
  • the resistance calculation unit 16 calculates the internal resistance R of the secondary battery unit 50 when the difference between the post-switching current integrated value ⁇ Ia and the pre-switching current integrated value ⁇ Ib is equal to or less than a predetermined difference threshold value.
  • the predetermined difference threshold value can be calculated by, for example, a predetermined threshold value Ith ⁇ standby time T ⁇ required coefficient ⁇ ( ⁇ is, for example, 0.1 ⁇ ⁇ ⁇ 2).
  • the predetermined threshold value Ith is a threshold value used when determining whether or not to calculate the internal resistance R of the secondary battery unit 50 based on the current after the elapse of the standby time T.
  • the difference in current values of the secondary battery unit 50 before and after charging and discharging is increased.
  • a state in which the tendency of charge transfer is different can be eliminated, and the calculation accuracy of the internal resistance R can be further improved.
  • FIG. 21 is a flowchart showing an example of the procedure of the internal resistance calculation process of the battery monitoring device 120 of the second embodiment.
  • the control unit 10 acquires the voltage of the secondary battery unit 50 (S71), acquires the current of the secondary battery unit 50 (S72), and integrates the current values (S73).
  • the control part 10 determines the presence or absence of switching of charging / discharging based on the acquired electric current (S74). The determination of whether or not charging / discharging is switched is the same as in the case of FIG. When charging / discharging is not switched (NO in S74), the control unit 10 continues the processing from step S71.
  • control unit 10 stores the voltage Vb and current Ib acquired immediately before the charge / discharge switching in the storage unit 20 (S75), and stores the current integrated value ⁇ Ib before switching. Calculate (S76).
  • the control unit 10 performs a standby time specifying process (S77).
  • the details of the waiting time specifying process are the same as in the case of FIG.
  • the control unit 10 measures time (S78). Note that the time measurement start time may be the time when it is determined that the charge / discharge switching is performed (the time when the above-described current voltage or current is acquired), or the time when the most recent (previous) voltage or current is acquired.
  • the control unit 10 determines whether or not the standby time has elapsed (S79). When the standby time has not elapsed (NO in S79), the control unit 10 continues the processing after step S78.
  • the control unit 10 acquires the voltage Vc of the secondary battery unit 50 (S80), acquires the current Ic of the secondary battery unit 50 (S81), and the post-switching current
  • the integrated value ⁇ Ia is calculated (S82).
  • the control unit 10 determines whether or not the acquired current Ic is equal to or greater than a predetermined threshold (S83).
  • the threshold value can be set to a value necessary for accurately calculating the internal resistance.
  • the control unit 10 determines whether or not the post-switching current integrated value ⁇ Ib (corresponding to the current integrated value ⁇ I) is within a predetermined range ( S84). When the post-switching current integrated value ⁇ Ib is within the predetermined range (YES in S84), the control unit 10 determines whether or not the difference between the post-switching current integrated value ⁇ Ib and the pre-switching current integrated value ⁇ Ia is equal to or less than the difference threshold value. Determine (S85).
  • the control unit 10 calculates the internal resistance (S86) and ends the process.
  • the internal resistance R is calculated when all three conditions of steps S83, S84, and S85 are satisfied, but the present invention is not limited to this.
  • the internal resistance R may be calculated when the two conditions of steps S83 and S84 are satisfied, or when the two conditions of steps S83 and S85 are satisfied.
  • the configuration of the battery monitoring device may be any of the configurations shown in FIGS.
  • the resistance calculation unit 16 does not calculate the internal resistance of the secondary battery unit 50 when the switching determination unit 14 determines that charging / discharging switching is within a predetermined time from the most recent determination.
  • the switching determination unit 14 can transmit a trigger (signal) when it is determined that charging / discharging is switched.
  • the predetermined time can be, for example, 50 ms, but is not limited thereto.
  • FIG. 22 is a schematic diagram showing a third example of the transition of current before and after the charge / discharge switching of the secondary battery unit 50.
  • the vertical axis represents current, and the positive side is charged and the negative side is discharged.
  • the horizontal axis indicates time.
  • a discharging current flows, and predetermined
  • the charging / discharging current is switched so that the charging current flows within the time (the time ⁇ t shown in FIG. 22 is within the predetermined time)
  • the charging current is switched (trigger transmission at the current charging / discharging switching time).
  • the internal resistance of the secondary battery unit 50 Since the calculation accuracy of the internal resistance of the unit 50 is deteriorated, the internal resistance of the secondary battery unit 50 is not calculated. In addition, when both the current value and voltage value of the secondary battery unit 50 do not change, it is considered as mere noise, and thus is not counted.
  • FIG. 23 is a flowchart showing an example of the procedure of the internal resistance calculation process of the battery monitoring device of the third embodiment.
  • the control unit 10 acquires the voltage of the secondary battery (S151), and acquires the current of the secondary battery (S152).
  • the control part 10 determines the presence or absence of switching of charging / discharging based on the acquired electric current (S153).
  • control unit 10 When there is no charge / discharge switching (NO in S153), the control unit 10 continues the processing from step S151.
  • the control unit 10 determines whether or not a predetermined time has elapsed since the last (most recent) trigger (signal) transmitted at the charging / discharging switching time ( S154). When the predetermined time has not elapsed (NO in S154), the control unit 10 stops the calculation of the internal resistance of the secondary battery and continues the processing from step S151.
  • control unit 10 stores the voltage Vb and current Ib acquired immediately before the charge / discharge switching in the storage unit 20 (S155).
  • the control unit 10 performs a standby time specifying process (S156).
  • the control unit 10 measures time (S157).
  • the time measurement start time may be the time when it is determined that the charge / discharge switching is performed (the time when the above-described current voltage or current is acquired), or the time when the most recent (previous) voltage or current is acquired.
  • the control unit 10 determines whether or not the standby time has elapsed (S158), and when the standby time has not elapsed (NO in S158), the processing from step S157 is continued.
  • the control unit 10 acquires the voltage Vc of the secondary battery (S159), and acquires the current Ic of the secondary battery (S160).
  • the control unit 10 determines whether or not the acquired current Ic is greater than or equal to a predetermined threshold (S161).
  • the threshold value can be set to a value necessary for accurately calculating the internal resistance.
  • the control unit 10 calculates the internal resistance (S162) and ends the process.
  • the control unit 10 ends the process without performing the process of step S162.
  • the configuration of the battery monitoring device may be any of the configurations shown in FIGS.
  • the resistance calculation unit 16 has a function as a current change degree calculation unit, and calculates a current change degree based on the current acquired by the current acquisition unit 12.
  • the current The degree of change (for example, a value obtained by differentiating the current with respect to time) can be calculated by, for example, an equation ⁇ I / ⁇ ts.
  • the resistance calculation unit 16 calculates the change degree calculated from the time when the switching determination unit 14 determines that there is charge / discharge switching until the standby time T specified by the standby time specification unit 15 elapses. If larger, the internal resistance of the secondary battery unit 50 is not calculated.
  • FIG. 24 is a schematic diagram showing a fourth example of the transition of current after charge / discharge switching of the secondary battery unit 50.
  • the vertical axis represents current, and the positive side is charged and the negative side is discharged.
  • the horizontal axis indicates time.
  • let t2 be the time when charging / discharging switching occurs
  • let t4 be the time when standby time T has elapsed.
  • the current change degree ⁇ I / ⁇ ts based on the current sampled and acquired between the time point t2 and the time point t4 is a predetermined change.
  • the degree threshold the internal resistance of the secondary battery unit 50 is not calculated.
  • the secondary battery unit is used when the change degree of the current increases after the standby time T elapses after the charge / discharge is switched. There is a possibility that 50 internal resistances cannot be accurately calculated. Therefore, when the degree of change in current is larger than a predetermined change degree threshold between the time when it is determined that charging / discharging is switched and before the standby time T elapses, the internal resistance of the secondary battery unit 50 is not calculated. By doing so, it is possible to prevent the calculation accuracy of the secondary battery unit 50 from being lowered.
  • FIG. 25 is a schematic diagram showing a fifth example of current transition after charge / discharge switching of the secondary battery unit 50.
  • the vertical axis represents current, and the positive side is charged and the negative side is discharged.
  • the horizontal axis indicates time.
  • let t2 be the time when charging / discharging switching occurs
  • let t4 be the time when standby time T has elapsed.
  • the current change degree ⁇ I / ⁇ ts based on the current sampled and acquired from time t2 to time t4 is smaller than a predetermined change degree threshold.
  • the current after the time point t4 when the standby time T has elapsed is greater than the predetermined threshold value Ith.
  • the internal resistance of the secondary battery unit 50 is calculated.
  • the change degree threshold value can be obtained by k ⁇ Ix / Ts. Note that the change degree threshold value can be appropriately changed according to the temperature, the degree of deterioration, and the like of the secondary battery unit 50. Note that the method of obtaining the change degree threshold value is an example, and is not limited to the above example.
  • FIG. 26 is a flowchart illustrating an example of the procedure of the internal resistance calculation process of the battery monitoring device 100 according to the fourth embodiment.
  • the control unit 10 acquires the voltage of the secondary battery (S181), and acquires the current of the secondary battery (S182).
  • the control part 10 determines the presence or absence of switching of charging / discharging based on the acquired electric current (S183).
  • control unit 10 When there is no charge / discharge switching (NO in S183), the control unit 10 continues the process after step S181. When the charge / discharge switching is performed (YES in S183), the control unit 10 stores the voltage Vb and current Ib acquired immediately before the charge / discharge switching in the storage unit 20 (S184).
  • the control unit 10 performs a standby time specifying process (S185).
  • the control unit 10 measures time (S186).
  • the control unit 10 determines whether or not the standby time has elapsed (S187). If the standby time has not elapsed (NO in S187), it is determined whether or not the current change degree is greater than a predetermined change degree threshold value. Determination is made (S188). When the current change degree is not larger than the predetermined change degree threshold value (NO in S188), the control unit 10 continues the processing from step S186.
  • the control unit 10 acquires the voltage Vc of the secondary battery (S189), and acquires the current Ic of the secondary battery (S190). The control unit 10 determines whether or not the acquired current Ic is equal to or greater than a predetermined threshold (S191).
  • the control unit 10 calculates the internal resistance (S192) and ends the process.
  • the control unit 10 performs the process of step S192. The process is finished without.
  • the internal resistance calculation device (battery monitoring device 100) of this embodiment can also be realized using a general-purpose computer including a CPU (processor), a RAM (memory), and the like. That is, as shown in FIG. 11 to FIG. 15, FIG. 21, FIG. 23 and FIG. 26, a computer program that defines the procedure of each process is loaded into a RAM (memory) provided in the computer, and the computer program is loaded into a CPU (processor).
  • the internal resistance calculation device (battery monitoring device 100) can be realized on a computer.
  • the secondary battery has been described as a lithium ion battery.
  • the secondary battery is not limited to a lithium ion battery, and can be provided, for example, as a nickel metal hydride battery or a nickel cadmium battery. .

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  • Tests Of Electric Status Of Batteries (AREA)
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Abstract

L'invention concerne un dispositif de calcul de résistance interne qui est pourvu : d'une unité d'acquisition de tension pour acquérir la tension d'une pile rechargeable ; d'une unité d'acquisition de courant pour acquérir le courant d'une pile rechargeable ; d'une unité de détermination de commutation pour déterminer qu'une commutation s'est produite entre la charge et la décharge de la pile rechargeable, sur la base du courant acquis ; d'une unité de spécification pour spécifier un intervalle d'attente, sur la base d'une bande de fréquence limite dans laquelle une impédance de diffusion, qui est provoquée par le processus de diffusion d'un ion prescrit et qui constitue une partie du spectre d'impédance de la pile rechargeable, contribue à l'impédance de la pile rechargeable ; d'une unité de calcul de résistance pour calculer la résistance interne de la pile rechargeable sur la base de la tension et du courant acquis après l'intervalle d'attente spécifié, lorsqu'il est déterminé qu'une commutation de charge/décharge s'est produite.
PCT/JP2016/068651 2015-09-18 2016-06-23 Dispositif de calcul de résistance interne, programme informatique et procédé de calcul de résistance interne WO2017047192A1 (fr)

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EP16846065.7A EP3351945B1 (fr) 2015-09-18 2016-06-23 Dispositif de calcul de résistance interne, programme informatique et procédé de calcul de résistance interne
US15/760,518 US10656213B2 (en) 2015-09-18 2016-06-23 Internal resistance calculation device, recording medium, and internal resistance calculation method
CN201680053573.8A CN108027396B (zh) 2015-09-18 2016-06-23 内部电阻计算装置、记录介质和内部电阻计算方法

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JP2016-083939 2016-04-19
JP2016083939A JP6614007B2 (ja) 2015-09-18 2016-04-19 内部抵抗算出装置、コンピュータプログラム及び内部抵抗算出方法

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JP2019039700A (ja) * 2017-08-23 2019-03-14 トヨタ自動車株式会社 二次電池の劣化状態推定方法および二次電池システム
WO2020149288A1 (fr) * 2019-01-15 2020-07-23 ゴイク電池株式会社 Dispositif de détection soh/soc pour élément de stockage d'énergie, et unité de gestion d'élément de stockage d'énergie
JP2021015015A (ja) * 2019-07-10 2021-02-12 ゴイク電池株式会社 蓄電素子管理ユニット
CN112698214A (zh) * 2019-10-23 2021-04-23 诺乌姆工程有限公司 估计电化学电池的电池状态
US11385296B2 (en) 2019-10-23 2022-07-12 NOVUM engineerING GmbH Estimating a battery state of an electrochemical battery
EP3812781A1 (fr) * 2019-10-23 2021-04-28 Novum engineerING GmbH Estimation de l'état d'une batterie électrochimique
CN112698214B (zh) * 2019-10-23 2024-03-19 诺乌姆工程有限公司 估计电化学电池的电池状态
EP4099039A1 (fr) 2021-06-01 2022-12-07 Kabushiki Kaisha Toshiba Procédé de détermination de vieillissement de batterie, appareil de détermination de vieillissement de batterie, système de gestion de batterie, dispositif monté sur batterie et programme de détermination de vieillissement de batterie
US11650262B2 (en) 2021-06-01 2023-05-16 Kabushiki Kaisha Toshiba Aging determination method of battery, aging determination apparatus of battery, management system of battery, battery-mounted device, and non-transitory storage medium
WO2023276547A1 (fr) * 2021-06-30 2023-01-05 株式会社デンソー Dispositif de mesure de batterie
CN115327419A (zh) * 2022-10-18 2022-11-11 长兴太湖能谷科技有限公司 一种蓄电池内阻参数的在线辨识方法
CN115327419B (zh) * 2022-10-18 2023-04-28 长兴太湖能谷科技有限公司 一种蓄电池内阻参数的在线辨识方法

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