WO2021205602A1 - Dispositif de commande de batterie secondaire, système de commande de batterie secondaire, bloc-batterie et procédé de commande de batterie secondaire - Google Patents

Dispositif de commande de batterie secondaire, système de commande de batterie secondaire, bloc-batterie et procédé de commande de batterie secondaire Download PDF

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WO2021205602A1
WO2021205602A1 PCT/JP2020/015972 JP2020015972W WO2021205602A1 WO 2021205602 A1 WO2021205602 A1 WO 2021205602A1 JP 2020015972 W JP2020015972 W JP 2020015972W WO 2021205602 A1 WO2021205602 A1 WO 2021205602A1
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secondary battery
soh
amount
curve
value
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PCT/JP2020/015972
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English (en)
Japanese (ja)
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拳 中村
靖博 ▲高▼木
佑輔 久米
英司 遠藤
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Tdk株式会社
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Priority to PCT/JP2020/015972 priority Critical patent/WO2021205602A1/fr
Publication of WO2021205602A1 publication Critical patent/WO2021205602A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a secondary battery control device, a secondary battery control system, a battery pack, and a secondary battery control method.
  • SOC State of Charge
  • SOH State of Health
  • SOC is an index indicating the state of charge (remaining capacity) of the secondary battery.
  • SOC is the ratio of the remaining capacity to the fully charged capacity.
  • SOH is an index indicating the deterioration state of the battery.
  • SOH is the ratio of the fully charged capacity at the time of deterioration to the initial fully charged capacity.
  • Patent Document 1 describes the maximum of the V-dQ / dV curve obtained from dQ / dV, which is the ratio of the amount of change in the amount of stored electricity to the amount of change in the voltage, and the voltage V of the secondary battery when the secondary battery is charged.
  • a method of estimating the capacity reduction rate (corresponding to SOH) from the voltage value of the point is described.
  • Patent Document 2 describes a method of obtaining dQ / dV when a secondary battery is discharged and obtaining SOH from the maximum value of the amount of change in dQ / dV with respect to voltage.
  • the present invention has been made in view of the above problems, and provides a secondary battery control device capable of estimating a deteriorated state of a secondary battery with high accuracy, a secondary battery control system including the control system, and a battery pack.
  • the purpose is.
  • Another object of the present invention is to provide a method for controlling a secondary battery, which can estimate the deteriorated state of the secondary battery with high accuracy.
  • Q P2 be the amount of electricity stored when dQ / dV P2 on the Q-dQ / dV curve.
  • DQ / dV of Q-dQ / dV on the curve is a (dQ / dV B2) + D / 2
  • the charged amount of time is between the storage amount Q B2 when the a Q P2 and dQ / dV B2
  • Q X A secondary battery control device that corrects the degree of deterioration SOH of the secondary battery calculated from the measured value of the amount of electricity stored in the secondary battery to N SOH obtained by the following formula (1).
  • N SOH AX + B ... (1)
  • X is an absolute value of the difference between Q P2 and Q X.
  • a and B are constants obtained in advance from the relationship between the X in the calibration sample and the degree of deterioration of the calibration sample. be.
  • the dQ / dV P2 is the maximum value of dQ / dV in the range where the charging voltage of the secondary battery is 3.65 V or more and less than 3.90 V.
  • the secondary battery control device described in. [4] The SOH correction means The measured value of the stored amount of the secondary battery is such that dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2, which corresponds to between Q P2 and Q B2.
  • the constant of A in the above equation (1) is when dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2 and is between Q P2 and Q B2.
  • the absolute value of the difference between Q P2 and Q X of the calibration sample corresponding to the measured value of the stored amount of the secondary battery and the degree of deterioration of the calibration sample when the absolute value of the difference is the minimum two. It is the slope of the regression line obtained by the multiplication method.
  • the secondary battery control device according to any one of [1] to [4], wherein the constant B in the formula (1) is an intercept of the regression line.
  • a secondary battery control system including the secondary battery control device according to any one of [1] to [5] and the secondary battery.
  • the secondary battery has a positive electrode and a negative electrode, and has a positive electrode and a negative electrode.
  • the positive electrode contains one or more of LiMO 2 (M is a transition metal element containing one or more selected from the group consisting of Co, Ni, Al, Mn and Fe) as a positive electrode active material.
  • a secondary battery pack comprising the control system for the secondary battery according to any one of [6] to [8] and a housing for accommodating the control system.
  • Q P2 be the amount of electricity stored when dQ / dV P2 on the Q-dQ / dV curve.
  • DQ / dV of Q-dQ / dV on the curve is a (dQ / dV B2) + D / 2
  • the charged amount of time is between the storage amount Q B2 when the a Q P2 and dQ / dV B2
  • Q X A method for controlling a secondary battery, in which the degree of deterioration SOH of the secondary battery calculated from the measured value of the amount of electricity stored in the secondary battery is corrected to N SOH obtained by the following formula (1).
  • N SOH AX + B ... (1)
  • X is an absolute value of the difference between Q P2 and Q X.
  • a and B are constants obtained in advance from the relationship between the X in the calibration sample and the degree of deterioration of the calibration sample. be.
  • the degree of deterioration SOH of the secondary battery calculated from the measured value of the stored amount of the secondary battery is corrected to the N SOH obtained by the formula (1). Therefore, a SOH value with a small error can be obtained. Since the control system and the secondary battery pack of the present invention include the control device of the secondary battery of the present invention, the deterioration state of the secondary battery can be estimated with high accuracy. Since the effects of the present invention facilitate the control of the secondary battery, the present invention contributes to the achievement of the sustainable goal of stable energy supply.
  • FIG. 1 is a block diagram showing an example of a battery pack according to an embodiment of the present invention.
  • FIG. 2 is a graph showing an example of the QdQ / dV curve of the secondary battery 4 provided in the battery pack shown in FIG.
  • FIG. 3 is a graph showing a part of the Q-dQ / dV curve of the calibration sample.
  • FIG. 4 is a schematic cross-sectional view showing an example of the secondary battery 4 provided in the battery pack shown in FIG.
  • FIG. 5 is a flowchart showing an example of a procedure for verifying the SOH corrected by the control method of the secondary battery of the present embodiment.
  • FIG. 1 is a block diagram showing an example of a battery pack according to an embodiment of the present invention.
  • the battery pack 1 includes a control system 2 and a housing 3 that houses the control system 2.
  • the control system 2 includes a secondary battery 4 and a control device 5. Signal communication is performed between the secondary battery 4 and the control device 5.
  • the signal communication may be wired or wireless.
  • the secondary battery 4 is, for example, a lithium secondary battery. The specific configuration of the secondary battery 4 will be described later.
  • the secondary battery 4 has at least one battery cell 41.
  • the secondary battery 4 provided in the battery pack 1 shown in FIG. 1 has a plurality of battery cells 41, 41, ....
  • the secondary battery 4 deteriorates with repeated charging and discharging.
  • SOH is an index indicating a deteriorated state of the secondary battery 4.
  • SOH is expressed as a ratio (%) of the capacity (Ah) from full charge to full discharge at the time of deterioration with respect to the capacity (Ah) from initial full charge to full discharge.
  • the control device 5 is a controller that controls the secondary battery 4, for example, a microcomputer. As shown in FIG. 1, the control device 5 includes a dQ / dV calculation means 51, a SOH correction means 52, a memory 53 (recording medium), and a CPU 54.
  • the memory 53 stores a computer-readable program for executing the control method of the secondary battery 4, which will be described later.
  • the CPU 54 executes the program stored in the memory 53.
  • the CPU 54 comprehensively controls the control device 5 and reads the program from the memory 53 to execute the control method of the secondary battery 4 and the like.
  • the control device 5 has a known SOC calculation means (not shown).
  • the control device 5 includes a known current integrating means for calculating the current integrated value (not shown), a known electric amount calculating means for calculating the amount of electricity (not shown), and a known voltage detecting means for detecting the discharge voltage (not shown). ) May have.
  • the dQ / dV calculation means 51 monitors (monitors) the charging voltage and the amount of electricity stored in the secondary battery 4 measured and input by a known measuring device. Further, the dQ / dV calculation means 51 calculates dQ / dV from the amount of change in the charging voltage and the amount of change in the amount of electricity stored in the secondary battery 4 per unit time. dQ / dV is the ratio of the amount of change in the amount of electricity stored to the amount of change in the charging voltage of the secondary battery 4. The calculation of dQ / dV may be performed at the time of charging, at the time of discharging, or at the time of charging and discharging.
  • the dQ / dV calculation means 51 uses the calculated dQ / dV to obtain a Q-dQ / dV curve as constant current charging characteristic information.
  • the Q-dQ / dV curve is a curve showing the relationship between the stored amount of the secondary battery 4 and dQ / dV, which is the ratio of the changed amount of the stored amount to the changed amount of the charging voltage of the secondary battery 4.
  • FIG. 2 is a graph showing an example of the Q-dQ / dV curve of the secondary battery 4 provided in the battery pack shown in FIG.
  • the horizontal axis represents the amount of electricity stored (capacity) of the secondary battery
  • the vertical axis represents dQ / dV.
  • the QdQ / dV curve shown in FIG. 2 has a plurality of peaks. More specifically, the QdQ / dV curve shown in FIG. 2 includes a peak top indicated by local maximum points P1, P2, P3, P4 and a peak bottom indicated by local minimum points B1, B2, B3, B4. ..
  • Each maximum point P1, P2, P3, P4 in the Q-dQ / dV curve corresponds to a portion (voltage stable region) where the potential is flat in the charge / discharge curve.
  • each minimum point B1, B2, B3, B4 in the QdQ / dV curve corresponds to a portion (voltage fluctuation region) in the charge / discharge curve where the potential fluctuation is large.
  • the plurality of peaks in the Q-dQ / dV curve are caused by the material of the positive electrode and / or the negative electrode forming the battery cell 41.
  • the maximum point P2 is the maximum associated with the voltage stable region that appears second when the charge curve when charging from the fully discharged state (low charge voltage side) is differentiated in the initial charge / discharge test of the secondary battery 4. It is a point.
  • the initial charge / discharge test indicates that the charge / discharge cycle is within 10 times.
  • the maximum point P2 is, for example, a peak based on the two-phase coexistence state of the stage 2L and the stage 2 in the stage structure of graphite when the negative electrode of the battery cell 41 contains graphite.
  • the minimum point B3 is the minimum associated with the voltage fluctuation region that appears third when the charge curve when charging from the fully discharged state (low charge voltage side) is differentiated in the initial charge / discharge test of the secondary battery 4.
  • the minimum point B3 is, for example, a peak associated with the completion of the single-phase reaction in the cubic crystal of lithium manganese oxide when the positive electrode of the battery cell 41 contains lithium manganese oxide (LMO).
  • the dQ / dV calculation means 51 calculates the following (A1) to (A5).
  • (A1) In the Q-dQ / dV curve, the dQ / dV value (dQ / dV P2 ) at the maximum point that appears second from the low charge rate side or a point that is mathematically equivalent to this.
  • the above (dQ / dV P2 ) may be the maximum value of dQ / dV in the range where the charging voltage of the secondary battery is 3.65 V or more and less than 3.90 V.
  • the above (dQ / dV B2 ) may be the minimum value of dQ / dV in the range where the charging voltage of the secondary battery is 3.65 V or more and less than 3.90 V.
  • dQ / dV P2 corresponds to dQ / dV at the maximum point P2
  • dQ / dV B2 corresponds to dQ / dV at the minimum point B2.
  • the amount of electricity stored Q X when dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2.
  • the storage amount Q X charged amount between the storage amount Q B2 when a storage amount Q P2 and dQ / dV B2 when a dQ / dV P2 Q X1 (in other words high The amount of electricity stored on the capacity side) is calculated.
  • the stored amount Q X is not the stored amount Q X2 (in other words, the stored amount on the low capacity side) between the stored amount Q P2 and the stored amount Q B1 when dQ / dV B1 but the stored amount Q P2 .
  • dQ / dV B1 is a dQ / dV value at the minimum point that appears first from the low charge rate side or a point that is mathematically equivalent to this.
  • dQ / dV B1 may be the minimum value of dQ / dV in the range where the charging voltage of the secondary battery is less than 3.65V.
  • the "mathematical equivalent value” means a value having an equivalent relationship by mathematical conversion.
  • the QdQ / dV curve is a QV curve differentiated by a voltage V. Therefore, each of the extremum points of dQ / dV is mathematically equivalent to the inflection point in the QV curve.
  • the Q-dQ / dV curve can be rewritten into a V-dQ / dV curve by mathematical conversion. For example, in the calculation of (A1) to (A5), the dQ / dV value at the extremum point (maximum point and minimum point) is changed to the dQ / dV value at the point mathematically equivalent to the extremum point. May be good.
  • (A1) to (A5) calculated by the dQ / dV calculation means 51 are sent to the SOH correction means 52.
  • the SOH correction means 52 uses (A1) to (A5) to obtain the N SOH of the degree of deterioration of the secondary battery 4 calculated from the measured value of the stored amount of the secondary battery 4 by the formula (1). Correct to.
  • N SOH AX + B ... (1)
  • X is an absolute value of the difference between Q P2 and Q X.
  • a and B are constants obtained in advance from the relationship between the X in the calibration sample and the degree of deterioration of the calibration sample. be.
  • the measured value of the stored amount of the secondary battery 4 is that dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2, and Q P2 .
  • X in the formula (1) is calculated, and the degree of deterioration SOH of the secondary battery 4 calculated from the measured value of the stored amount of the secondary battery 4 is calculated by the formula. Correct to N SOH obtained in (1).
  • the constants A and B in the formula (1) are constants obtained in advance from the relationship between X in the calibration sample and the degree of deterioration of the calibration sample.
  • the constants A and B in the formula (1) are values calculated based on the results of the charge / discharge test of the calibration sample performed in advance.
  • the constants A and B are stored in the memory 53 in advance.
  • the constants A and B stored in the memory 53 are read from the memory 53 when the SOH correction means 52 corrects the SOH to N SOH.
  • the constant of A in the equation (1) is a secondary battery when dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2 and is between Q P2 and Q B2.
  • the absolute value of the difference between Q P2 and Q X of the calibration sample corresponding to the measured value of the amount of electricity stored in 4 and the degree of deterioration of the calibration sample when it is the absolute value of the difference between Q P 2 and Q X. It is the slope of the regression line obtained by using the least squares method.
  • the constant of B in the equation (1) is an intercept of the regression line.
  • the constants A and B are obtained, for example, by the method shown below.
  • a calibration sample As the calibration sample, a sample having the same capacity and made of the same material as the secondary battery 4 actually used is prepared. The deterioration behavior of the calibration sample of the same material and the same capacity is similar to the deterioration behavior of the secondary battery 4 actually used.
  • FIG. 3 is a graph showing a part of the Q-dQ / dV curve of the calibration sample.
  • the numerical value described as a legend of the QdQ / dV curve shown in FIG. 3 is the degree of deterioration (SOH (%)) of the calibration sample.
  • the numerical value 100 described as a legend of the Q-dQ / dV curve is the Q-dQ / dV curve of the calibration sample in the initial state.
  • SOH degree of deterioration
  • dQ / dV P2 becomes smaller and the position of the stored amount (capacity) Q P2 changes.
  • the behavior of the change in the dQ / dV and the capacity of the extremum point of the QdQ / dV curve due to the deterioration of the calibration sample is substantially the same as the behavior of the change in the extremum point due to the deterioration of the secondary battery 4.
  • the above (A1) to (A5) in the calibration sample are calculated using the Q-dQ / dV curve of the calibration sample.
  • the above (A1) to (A5) are obtained every time a predetermined number of charge / discharge cycles are performed on the calibration sample.
  • the degree of deterioration (SOH) of the calibration sample is obtained by dividing the capacity (Ah) when fully charged to fully discharged in the number of cycles by the capacity (Ah) when fully discharged from the initial full charge.
  • the absolute value X 1 of the difference between Q P2 and Q X1 when dQ / dV in Q-dQ / dV on the curve is (dQ / dV B2) + D / 2, the absolute value X of the difference
  • the absolute value X 1 of the difference between Q P2 and Q X1 when dQ / dV in Q-dQ / dV on the curve is (dQ / dV B2) + D / 2
  • the absolute value X 1 of the difference The error of the regression line obtained by using the least squares method with the degree of deterioration of the calibration sample at a certain time is small.
  • the constant of A in the equation (1) is the slope of the regression line.
  • the constant of B in the equation (1) is an intercept of the regression line.
  • the shape between the maximum point P2 and the minimum point B2 on the Q-dQ / dV curve is deteriorated in the calibration sample as compared with the shape between the minimum point B1 and the maximum point P2.
  • the shape change due to is small. This is due to the following reasons. As shown in FIG. 3, between the maximum point P2 and the minimum point B1 on the QdQ / dV curve is smaller than the maximum point P2 which affects the shape between the maximum point P2 and the minimum point B1. There is a peak.
  • the distance between the maximum point P2 and the minimum point B2 on the Q-dQ / dV curve is smaller than the maximum point P2 having a size that affects the shape between the maximum point P2 and the minimum point B2. This is because no peak is seen.
  • the shape between the maximum point P2 and the minimum point B2 on the Q-dQ / dV curve is a shape due to deterioration of the calibration sample as compared with the shape between the minimum point B1 and the maximum point P2. The change is small.
  • Q-dQ / dV dQ on the curve / dV is (dQ / dV B2) + D / 2 and Q P2 when a absolute value X 1 of the difference between Q X1, the absolute value X 1 of the difference between the deterioration degree of the time is, the absolute value X 2 of the difference between Q P2 and Q X2, compared to between deterioration degree of when said difference is an absolute value X 2, higher There is a correlation. Therefore, the absolute value X 1 of the difference between Q P2 and Q X1, the deterioration degree of the calibration samples when the absolute value X 1 of the difference, the regression line obtained by the least square method, more The error is small.
  • the constants A and B in the formula (1) are such that the measured value of the stored amount of the secondary battery 4 is (dQ / dV B2 ) + D / 2 and dQ / dV on the Q-dQ / dV curve is Q. It is used when corresponding between P2 and QB2.
  • the constants A and B in equation (1) are the absolute difference between Q P2 and Q X 1 of the calibration sample when dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2.
  • the value X 1 is determined by the regression line of the deterioration degree of the calibration sample when an absolute value X 1 of said difference. This regression line has a small error.
  • the SOH correction means 52 sends the correction value corrected to N SOH obtained by the equation (1) to the secondary battery 4.
  • the deterioration degree SOH of the secondary battery 4 is replaced with N SOH.
  • Replacement of the SOH of the N SOH for example, can be performed when the N SOH is obtained in SOH correction means 52.
  • the replacement of SOH with N SOH may be performed, for example, at the time of charging each time the selected extremum point is passed.
  • the difference between the possessed value (SOH before replacement) and N SOH at the time when N SOH is obtained is replaced. It may be done by adding it to the holding value at the time.
  • the replacement from SOH to N SOH is performed from the correction value acquisition point so that the value corresponding to the difference between the possession value and the correction value at the time when the correction value is obtained is added to the possession value at the correction completion point.
  • the value may be gradually corrected until the correction completion point.
  • FIG. 4 is a schematic cross-sectional view showing an example of the secondary battery 4 provided in the battery pack shown in FIG.
  • the secondary battery 4 shown in FIG. 4 includes, for example, at least one battery cell 41, an exterior body 42, and an electrolytic solution (not shown).
  • the secondary battery 4 shown in FIG. 4 includes one battery cell 41 for convenience of explanation.
  • the secondary battery 4 included in the control system 2 is not limited to the example shown in FIG. 1, and may include a laminated body in which a plurality of battery cells are laminated.
  • the battery cell 41 is connected to the outside via a pair of terminals 43.
  • the exterior body 42 covers the periphery of the battery cell 41.
  • the exterior body 42 is, for example, a metal laminate film in which a metal foil 42A is coated with a resin layer 42B from both sides.
  • the electrolytic solution is housed in the exterior body 42 and impregnated in the battery cell 41.
  • the battery cell 41 includes a positive electrode 41A, a negative electrode 41B, and a separator 41C.
  • the separator 41C is sandwiched between the positive electrode 41A and the negative electrode 41B.
  • the separator 41C is, for example, a film having an electrically insulating porous structure. As the separator 41C, a known one can be used.
  • the positive electrode 41A has a positive electrode current collector 41AA and a positive electrode active material layer 41AB.
  • the positive electrode current collector 41AA is, for example, a conductive plate material.
  • the positive electrode active material layer 41AB is formed on at least one surface of the positive electrode current collector 41AA.
  • the positive electrode active material layer 41AB may be formed on both surfaces of the positive electrode current collector 41AA.
  • the positive electrode active material layer 41AB has, for example, a positive electrode active material, a conductive auxiliary material, and a binder.
  • the positive electrode active material reversibly proceeds with the occlusion and release of lithium ions, the desorption and insertion (intercalation) of lithium ions, or the doping and dedoping of lithium ions and counter anions.
  • the positive electrode 41A preferably contains one or more LiMO 2 (M is a transition metal element containing one or more selected from the group consisting of Co, Ni, Al, Mn and Fe) as the positive electrode active material. ..
  • Examples of the positive electrode active material include lithium cobalt oxide (LCO), lithium nickel cobalt manganese composite oxide (NCM), lithium nickel cobalt aluminum composite oxide (NCA), lithium manganese oxide (LMO), and lithium iron phosphate (LMO). LFP) and the like.
  • the positive electrode active material layer 41AB may contain a plurality of these positive electrode active materials.
  • the positive electrode active material is not limited to these, and known materials can be used. Known conductive auxiliary materials and binders can be used.
  • the negative electrode 41B has a negative electrode current collector 41BA and a negative electrode active material layer 41BB.
  • the negative electrode current collector 41BA is, for example, a conductive plate material.
  • the negative electrode active material layer 41BB is formed on at least one surface of the negative electrode current collector 41BA.
  • the negative electrode active material layer 41BB may be formed on both surfaces of the negative electrode current collector 41BA.
  • the negative electrode active material layer 41BB has, for example, a negative electrode active material, a conductive auxiliary material, and a binder.
  • the negative electrode active material may be any compound that can occlude and release ions, and a known negative electrode active material used in a lithium ion secondary battery can be used.
  • the negative electrode active material is, for example, graphite.
  • metallic lithium, a silicon compound, or the like may be used as the negative electrode active material.
  • the electrolytic solution is sealed in the exterior body 42 and impregnated in the battery cell 41.
  • As the electrolytic solution a known one can be used.
  • the battery pack 1 of the present embodiment has a control system 2 including a control device 5 of the secondary battery 4.
  • the control device 5 of the secondary battery 4 corrects the deterioration degree SOH of the secondary battery calculated from the measured value of the stored amount of electricity in the secondary battery 4 to the N SOH obtained by the equation (1). Therefore, in the control device 5 of the secondary battery 4 of the present embodiment, and the battery pack 1 and the control system 2 including the control device 5, the deteriorated state of the secondary battery 4 can be estimated with high accuracy.
  • FIG. 5 is a flowchart showing an example of a procedure for verifying the SOH corrected by the control method of the secondary battery of the present embodiment.
  • the flowchart shown in FIG. 5 is executed by, for example, the CPU 54 included in the battery pack 1 shown in FIG.
  • the secondary battery 4 is obtained (step S11).
  • the secondary battery 4 is fully discharged at 25 ° C. with a constant current corresponding to 0.2 C (step S12).
  • 1C represents a current value for discharging the reference capacity of the battery in 1 hour
  • 0.2C represents a current value of 1/5 of that.
  • the battery is fully charged at 25 ° C. with a constant current corresponding to 0.2 C (step S13).
  • the control device 5 starts detecting the voltage and the current value of the secondary battery 4 at the same time as the start of charging, and obtains the integrated current value.
  • the dQ / dV calculating means 51 of the control device 5 obtains the electric energy Q from the obtained integrated current value, and calculates the value of dQ / dV. As a result, the control device 5 acquires the QdQ / dV curve in the initial state (step S14) and records it in the memory 53. At the same time, the control device 5 records the initial full charge capacity and the SOH in the initial state in the memory 53 (step S15).
  • step S16 100 cycles of charge / discharge cycles shown below are performed on the secondary battery 4 in the initial state (step S16). That is, at 45 ° C., full discharge is performed with a constant current corresponding to 0.5 C. After that, it is fully charged with a constant current corresponding to 0.5C. This charge / discharge cycle is performed 100 cycles.
  • step S17 a full discharge (step S17) is performed at a constant current corresponding to 0.2 C at 25 ° C., and a full charge is performed again at a constant current corresponding to 0.2 C at 25 ° C. (step S18).
  • step S19 the value of dQ / dV is calculated and the Q ⁇ dQ / dV curve is acquired (step S19).
  • the control device 5 compares the Q-dQ / dV curve acquired in step S19 with the Q-dQ / dV curve acquired in step S14 in the initial state (step S20). Then, when it is determined by the control device 5 that no change is observed between the Q-dQ / dV curve acquired in step S19 and the Q-dQ / dV curve acquired in step S14 in the initial state, step. Return to S16.
  • step S20 when it is determined by the control device 5 that a change is observed between the Q-dQ / dV curve acquired in step S19 and the Q-dQ / dV curve acquired in step S14 in the initial state.
  • the control device 5 determines that the secondary battery 4 has deteriorated, and records the SOH in the memory 53 (step S21).
  • the control device 5 starts charging the secondary battery 4 and continuously or intermittently calculates dQ / dV. Further, in the SOH correction means 52 of the control device 5, the measured value of the stored amount of the secondary battery 4 is that dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2, and Q. It is determined whether or not it corresponds to the time between P2 and Q B2. Then, when the measured value of the stored amount of the secondary battery 4 is that dQ / dV on the Q-dQ / dV curve is (dQ / dV B2 ) + D / 2, and is between Q P2 and Q B2.
  • the control device 5 calculates the N SOH obtained by the equation (1) (step S22). Then, the control device 5 confirms that the calculated N SOH and the SOH corrected by the SOH correction means 52 match or substantially match (step S23). By the above verification procedure, it can be estimated whether or not the SOH is corrected by the control device 5.
  • Example 1 A lithium ion secondary battery was manufactured as the secondary battery.
  • a positive electrode was prepared.
  • Lithium nickel cobalt manganese composite oxide (NCM) LiNi 0.33 Mn 0.33 Co 0.33 O 2
  • lithium manganese oxide (LMO) LiMn 2 O 4
  • carbon black as conductive material
  • PVDF Polyvinylidene fluoride
  • NCM which is the positive electrode active material, LMO, the conductive material, and the binder
  • NCM LMO: conductive material: binder
  • the negative electrode was prepared.
  • Graphite was prepared as the negative electrode active material
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • These were dispersed in distilled water to prepare a paint, which was applied onto a negative electrode current collector made of copper foil.
  • the mass ratio of the negative electrode active material to the binder and the thickener was 95: 3: 2 (negative electrode active material: binder: thickener). After coating, it was dried to prepare a negative electrode sheet having a basis weight of 6.0 mg / cm 2 of the negative electrode active material.
  • the positive electrode and the negative electrode prepared above were laminated via a separator.
  • a laminate of polyethylene and polypropylene was used as the separator.
  • the obtained laminate was impregnated with an electrolytic solution, sealed inside the exterior, and vacuum-sealed.
  • an electrolytic solution a solvent obtained by dissolving 1.5 mol / L of lithium hexafluorophosphate (LiPF 6 ) in a solvent in which equal amounts of ethylene carbonate (EC) and dimethyl carbonate (DEC) were mixed was used. Through the above steps, a lithium secondary battery for evaluation was produced.
  • the charge / discharge cycle was repeated 1000 cycles for the lithium secondary battery for evaluation.
  • the condition of one charge / discharge was that at 0 ° C., the battery was charged to a final voltage of 4.2 V with a constant current corresponding to 0.1 C, and then discharged to 3.0 V with a constant current corresponding to 0.1 C.
  • 1C represents the current value for discharging the reference capacity of the battery in 1 hour
  • 0.1C represents the current value of 1/10 of the current value.
  • the measured SOH is the capacity (Ah) when the lithium secondary battery for evaluation, which has been repeated for 1000 cycles, is fully charged to fully discharged at an environmental temperature of 25 ° C., and the capacity (Ah) when it is fully discharged from the initial full charge. ) Divided by.
  • variable X when the measured value of the stored amount of the lithium secondary battery for evaluation is (dQ / dV B2 ) + D / 2 on the Q-dQ / dV curve is the upper limit dQ shown below.
  • / dV with the lower limit dQ / dV, Q X, was calculated by the following method.
  • N SOH (%) calculated by the following formula (1) was obtained.
  • N SOH AX + B ... (1) Then, the difference (absolute value) between the calculated N SOH (%) and the measured SOH (%) was obtained.
  • the results are shown in Table 1.
  • Example 1 A lithium secondary battery for evaluation was produced in the same manner as in Example 1, and the measured SOH (%) was determined. Further, in the same manner as in Example 1, a calibration sample was prepared and a charge / discharge test was performed. Using the result, it calculates the calibration sample of dQ / dV P2 when dQ / dV in Q-dQ / dV on the curve is dQ / dV P2 (maximum point P2), and a variable X. Also, a variable X (dQ / dV P2), a regression line with the deterioration degree of the calibration samples with its dQ / dV P2, was determined using the least squares method.
  • Example 2 A lithium secondary battery for evaluation was produced in the same manner as in Example 1, and the measured SOH (%) was determined. Further, in the same manner as in Example 1, a calibration sample was prepared and a charge / discharge test was performed. Using the result, it calculates the dQ / dV B2 of the calibration samples when dQ / dV on Q-dQ / dV curve is dQ / dV B2 (minimum point B2), and a variable X. Also, a variable X (dQ / dV B2), a regression line with the deterioration degree of the calibration samples with its dQ / dV B2, was determined using the least squares method.
  • the storage amount between Q P2 when dQ / dV P2 on the Q-dQ / dV curve and the storage amount Q B2 when dQ / dV B2 was defined as the stored amount Q x of Comparative Example 5.
  • the storage amount between Q P2 when dQ / dV P2 on the Q-dQ / dV curve and the storage amount Q B2 when dQ / dV B2 The amount Q X1 (that is, Q P2 ⁇ Q X ) was defined as the stored amount Q x of Comparative Example 6.
  • Example 1 the upper limit dQ / dV in Comparative Examples 1-7, the lower limit dQ / dV, dQ in Q-dQ / dV on the curve corresponding to Q X / dV, variables X, constants A, constant B , N SOH (%), measured SOH (%), and the difference between N SOH and measured SOH (measured SOH-N SOH ) (%).
  • Example 1 As shown in Table 1, in Example 1, the difference between N SOH (%) and the actually measured SOH (%) was 3%, which was smaller than that of Comparative Examples 1 to 7. It is presumed that this is because in Comparative Examples 1 to 7, the error of the regression line obtained to determine the constant A and the constant B is larger than that of the first embodiment.

Abstract

Lorsqu'une valeur de dQ/dV à un second point maximal à partir d'un côté à faible taux de charge ou un point mathématiquement équivalent du second point maximal est (dQ/dVP2, une valeur de dQ/dV à un second point minimal à partir du côté à faible taux de charge ou un point mathématiquement équivalent du second point minimal est (dQ/dVB2), la différence entre dQ/dVP2 et dQ/dVB2 est D, une quantité de charge à dQ/dVP2 sur une courbe Q-dQ/dV est QP2, dQ/dV sur la courbe Q-dQ/dV est (dQ/dVB2)+D/2, et une quantité de charge entre QP2 et QB2 à dQ/dVB2 est QX, ce procédé de commande de batterie secondaire corrige, à NSOH obtenu selon l'équation suivante, le degré de dégradation de SOH de la batterie secondaire calculé à partir d'une valeur de mesure réelle de la quantité de charge de la batterie secondaire. NSOH=AX+B (X représente la valeur absolue de la différence entre QP2 et QX, et A et B sont des valeurs constantes précédemment obtenues à partir de la relation entre X dans un échantillon d'étalonnage et le degré de dégradation de l'échantillon d'étalonnage La présente invention facilite la commande de la batterie secondaire, et ainsi, la présente invention contribue à l'atteinte d'une cible durable telle qu'une alimentation stable en énergie.
PCT/JP2020/015972 2020-04-09 2020-04-09 Dispositif de commande de batterie secondaire, système de commande de batterie secondaire, bloc-batterie et procédé de commande de batterie secondaire WO2021205602A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016014588A (ja) * 2014-07-02 2016-01-28 日産自動車株式会社 バッテリ管理装置
JP2019056595A (ja) * 2017-09-20 2019-04-11 三菱自動車工業株式会社 二次電池システム

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016014588A (ja) * 2014-07-02 2016-01-28 日産自動車株式会社 バッテリ管理装置
JP2019056595A (ja) * 2017-09-20 2019-04-11 三菱自動車工業株式会社 二次電池システム

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