JP5492493B2 - Charge power limit value calculation device - Google Patents

Description

  The present invention relates to a charging power limit value calculation device that determines a charging power limit value for a battery for supplying vehicle driving power.

  Electric vehicles such as electric vehicles and hybrid vehicles are widely used. The electric vehicle includes a motor generator, and is accelerated by a driving force of the motor generator and decelerated by regenerative power generation braking of the motor generator. In order to supply electric power to the motor generator and collect electric power generated by the motor generator, a secondary battery that can be repeatedly charged and discharged is mounted on the electric vehicle.

  The following Patent Document 1 and Patent Document 2 describe a technique for limiting the charge / discharge power of a battery in relation to the problem to be solved by the present invention. Non-Patent Document 1 and Patent Document 2 below describe an electrochemical model of a battery used for charge / discharge control according to the present invention.

JP 2003-219510 A JP 2008-42960 A

WBGu and CYWang, “Thermal-ELECTROCHEMICAL COUPLED MODELING OF A LITHIUM-ION CELL”, ECS Proceedings Vol.99-25 (1), 2000 (USA), Electrochemical Society (ECS), 2000, pp 743-762

  The charging performance of the battery varies depending on usage conditions such as charging power and battery temperature. For this reason, when charge control is performed so that charging is performed with a constant power, there arises a problem that the battery cannot be charged with the maximum allowable power. On the other hand, if the battery is charged with excessive power exceeding the charging capacity at that time, there arises a problem that the life of the battery is shortened, for example, the charge capacity is quickly reduced.

  The present invention has been made for such a problem. That is, in a charging power limit value calculation device that calculates a charging power limit value for a battery for supplying vehicle driving power, an optimum charging power limit value is determined according to the use condition of the battery, the state of the battery, and the charging characteristics of the battery. Objective.

The present invention provides a sensor for measuring a current flowing in a battery for supplying vehicle driving power , an output voltage of the battery, and a temperature of the battery, and a battery model formula for the battery based on each measurement result of the sensor. A battery state quantity estimation unit for obtaining a battery state quantity including a battery model parameter of the battery, and charging power to the battery when the battery is charged at a constant voltage based on the battery model formula. A charging allowable voltage generator for setting a charging voltage limit value, and a time change in charging power to the battery when the battery is charged at a constant voltage with the voltage of the charging voltage limit value. , based on said battery model equation, a chargeable power prediction unit for obtaining a chargeable power characteristics, the based on the battery state quantity and the charging voltage limit value, Comprising a chargeable power prediction unit for obtaining the said charging electric power characteristics, and on the basis of the chargeable power characteristics, and wherein the Rukoto calculated charging power limit value in charging actually the battery.

In the charging power limit value calculation device according to the present invention, the chargeable power characteristic is a characteristic that the chargeable power increases and becomes maximum after the start of charging and then decreases with time, and the charging power limit value calculation apparatus, based on said chargeable power characteristics, a rechargeable power observed when the predetermined time period from the reference time corresponding to the initial time of the operation by the battery model equation has elapsed, the power limit value setting determined as the limit charging power It is suitable to provide a part.

In the charging power limit value computing device according to the present invention, the battery state quantity estimating unit obtains a charging depth of the battery based on the battery state quantity, and the charging power limit value computing device obtains the obtained charging depth. it is preferable to obtain Bei between adjustment portion when the shall be determined as the predetermined time between time as has long large.

In the charging power limit value calculation device according to the present invention, a deterioration degree estimation unit that obtains a deterioration degree of the charge capacity of the battery and is represented by a change with time of a charge amount that can be discharged at full charge , and and during adjustment portion when the amount of time as has long greater deterioration degree determined by the deterioration degree estimation portion shall be determined as the predetermined time, it is preferable to obtain Bei a.

In charge power limit value calculation device according to the present invention, the allowable charge voltage generator, preferably you to set a smaller value the larger the deterioration degree determined by said deterioration degree estimation portion as the charging voltage limit value It is.

In charge power limit value calculation device according to the present invention is a deterioration of the charging ability of the previous SL cell includes a deterioration degree estimation unit for obtaining a degradation degree represented by the aging of the fully charged during discharge charge quantity the chargeable voltage generator, that you set a smaller value the larger the deterioration degree determined by said deterioration degree estimation portion as the charging voltage limit value is preferable.

In charge power limit value calculation device according to the present invention, the battery state estimation unit obtains the charging depth of the battery based on the battery state quantity, the chargeable voltage generator, the previous KiTakashi electrostatic depth that you set a smaller value the larger as the charging voltage limit value is preferable.

In charge power limit value calculation device according to the present invention, a battery current control unit for changing the current flowing through the battery, based on a change in the output voltage of the battery for the current change by the battery current controller, for said battery , JP and a battery characteristic determining unit for determining the characteristic constants including the exchange current density and the diffusion coefficient, the battery state estimation unit, in addition to the measurement result of the sensor, determined by the battery characteristic determining unit obtains the battery state quantity based on sex constant, the chargeable power prediction unit, in addition to the charging voltage limit value and the battery state quantity based on said characteristic constants obtained by said battery characteristic determining unit the chargeable power characteristic is preferably determined Mel possible.

  According to the present invention, it is possible to obtain an optimum charging power limit value for a battery according to the use condition of the battery.

It is a figure which shows the structure of the vehicle electric power control system which concerns on 1st Embodiment. It is a figure which shows the structure of the electric power limit value calculating apparatus which concerns on 1st Example. It is a figure which shows the structure and electrochemical model of a battery cell. It is a figure which shows a battery model parameter. It is a figure which shows the time waveform and chargeable electric power characteristic of a charging voltage limiting value. It is a figure which shows the structure of the electric power limit value calculating apparatus which concerns on 2nd Example. It is a figure which shows the structure of the electric power limit value calculating apparatus which concerns on 3rd Example. It is a figure which shows the example of the relationship which a charging depth versus voltage limiting value table shows. It is a figure which shows the time waveform and chargeable electric power characteristic of a charging voltage limiting value. It is a figure which shows the structure of the electric power limit value calculating apparatus which concerns on 4th Example. It is a figure which shows the example of the relationship which the charge time versus calculation time table shows. It is a figure which shows the chargeable electric power characteristic. It is a figure which shows the structure of the electric power limit value calculating apparatus which concerns on 5th Example. It is a figure which shows the structure of the electric power control system for vehicles which concerns on 2nd Embodiment. It is a figure which shows the structure of the battery diagnosis / electric power limit value calculating apparatus which concerns on 1st Example. It is a figure which shows the example of the time waveform of the battery voltage measured value according to the time waveform of the battery current controlled by the current control apparatus, and the battery current. It is a figure which shows the structure of the battery diagnosis / power limit value calculating apparatus which concerns on 2nd Example. It is a figure which shows the example of the relationship which a deterioration degree versus voltage limiting value table shows. It is a figure which shows the time waveform and chargeable electric power characteristic of a charging voltage limiting value. It is a figure which shows the structure of the battery diagnosis / power limit value calculating apparatus which concerns on 3rd Example. It is a figure which shows the example of the relationship which the deterioration time versus time table for a calculation shows. It is a figure which shows the chargeable electric power characteristic. It is a figure which shows the structure of the battery diagnosis / power limit value calculating apparatus which concerns on 4th Example. It is a figure which shows the structure which combined the 4th Example of the power limit value calculating device which concerns on 1st Embodiment, and the 2nd Example of the battery diagnosis / power limit value calculating device which concerns on 2nd Embodiment. It is a figure which shows the structure which combined the 3rd Example of the power limit value calculating device which concerns on 1st Embodiment, and the 3rd Example of the battery diagnosis / power limit value calculating device which concerns on 2nd Embodiment.

  FIG. 1 shows a configuration of a vehicle power control system according to a first embodiment of the present invention. The vehicle power control system supplies the electric power of the battery 10 to the motor generator 14 to drive the vehicle, charges the battery 10 with the electric power generated by the motor generator 14 and regeneratively brakes the vehicle. The battery 10 can be a lithium ion battery that can be repeatedly charged and discharged.

  The operation unit 16 includes an accelerator pedal, a brake pedal, and the like, and outputs operation command information corresponding to a user operation to the power control device 12.

  The power control device 12 performs AC / DC conversion between the motor generator 14 and the battery 10 while adjusting each applied voltage. When the electric power control device 12 causes the motor generator 14 to generate acceleration torque in accordance with the operation command information, the electric power control device 12 sets the voltage applied to the battery 10 and the motor generator 14 so that electric power is supplied from the battery 10 to the motor generator 14. adjust. Further, the power control device 12 is applied to the battery 10 and the motor generator 14 so that power is supplied from the motor generator 14 to the battery 10 when the motor generator 14 generates regenerative braking torque based on the operation command information. Adjust the voltage.

  When electric power is supplied from the motor generator 14 to the battery 10, the battery 10 is charged. At this time, the power control device 12 adjusts the charging power supplied to the battery 10 so as not to exceed the charging power limit value Win output by the power limit value calculation device 24.

  The vehicle power control system includes a current sensor 18 that measures the current flowing through the battery 10, a voltage sensor 20 that measures the output voltage of the battery 10, and the battery 10, in order for the power limit value calculation device 24 to obtain the charging power limit value Win. The temperature sensor 22 which measures the temperature of is provided. The current sensor 18 outputs the measurement result as the battery current measurement value Ib to the power limit value calculation device 24, and the voltage sensor 20 outputs the measurement result as the battery voltage measurement value Vb to the power limit value calculation device 24. Further, the temperature sensor 22 outputs the measurement result to the power limit value calculation device 24 as the battery temperature measurement value Tb.

  Based on the battery current measurement value Ib, the battery voltage measurement value Vb, and the battery temperature measurement value Tb, the power limit value calculation device 24 calculates the charge power limit value Win and outputs it to the power control device 12.

  FIG. 2 shows the configuration of the power limit value calculation device 24 according to the first embodiment. In order to describe the process executed by the battery state quantity estimation unit 26, here, an example of an electrochemical model of the battery 10 will be described based on the content of Patent Document 2.

  The battery 10 can be configured by connecting a plurality of battery cells in series. FIG. 3 shows the configuration of the battery cell. The battery cell includes a negative electrode 34, a separator 38, and a positive electrode 36. The separator 38 is configured by impregnating an electrolytic solution into a resin provided between the negative electrode 34 and the positive electrode 36.

The negative electrode 34 and the positive electrode 36 are composed of an aggregate of spherical active materials. A chemical reaction that releases or absorbs lithium ions Li ⁺ and electrons e ⁻ is performed on the interface of the active material 40 of the negative electrode 34. On the other hand, a chemical reaction that absorbs or releases lithium ions Li ⁺ and electrons e ⁻ is performed on the interface of the active material 42 of the positive electrode 36.

The negative electrode 34 is provided with a negative electrode collector 44 that conducts electrons e ⁻ to and from the negative electrode terminal 48, and the positive electrode 36 is provided with a positive electrode collector 46 that conducts electrons e ⁻ to and from the positive electrode terminal 50. The metal material used for the negative electrode collector 44 and the positive electrode collector 46 is determined based on the magnitude relationship of the ionization tendency. Generally, the negative collector 44 is made of copper, and the positive collector 46 is made of aluminum.

When the lithium ions Li ⁺ are exchanged between the positive electrode 36 and the negative electrode 34 via the separator 38, the charging current flows out of the positive electrode terminal 50 and flows into the negative electrode terminal 48 via the external circuit 52 to the battery cell. Alternatively, a discharge current that flows out from the negative terminal 48 and flows into the positive terminal 50 through the external circuit 52 flows.

An electrochemical model of the battery cell will be described with reference to FIG. At the time of discharge, electrons e ⁻ are emitted from the active material 40 of the negative electrode 34 to the negative electrode collector 44, and the lithium atoms Li in the active material 40 of the negative electrode 34 become lithium ions Li ⁺ . At the same time, lithium ions Li ⁺ are released from the active material 40 of the negative electrode 34 to the electrolytic solution in the separator 38. The active material 42 of the positive electrode 36 takes in lithium ions Li ⁺ from the electrolytic solution, absorbs electrons e ⁻ from the positive electrode collector 46, and takes in lithium atoms Li inside the active material 42 of the positive electrode 36. As a result, a discharge current that flows out from the positive collector 46 and flows into the negative collector 44 through the external circuit 52 flows.

On the other hand, at the time of charging, electrons e ⁻ are released from the active material 42 of the positive electrode 36 to the positive electrode collector 46, and lithium ions Li ⁺ are released from the active material 42 of the positive electrode 36 to the electrolytic solution in the separator 38. The active material 40 of the negative electrode 34 takes in lithium ions Li ⁺ from the electrolytic solution, absorbs electrons e ⁻ from the negative electrode collector 44, and takes in lithium atoms Li inside the active material 40 of the negative electrode 34. As a result, a charging current that flows out of the negative electrode collector 44 and flows into the positive electrode collector 46 through the external circuit 52 flows.

  For the analysis of the electrochemical model, an electrode reaction on each surface of the active materials 40 and 42 during charging and discharging, diffusion of lithium ions in each active material 40 and 42 in the radial direction, and lithium in the electrolyte solution A battery model formula for ion diffusion, potential distribution at each site, and the like is used. The battery model formula is expressed by the following formulas (M1) to (M15). Details of these equations are described in Non-Patent Document 1.

  FIG. 4 shows battery model parameters used in equations (M1) to (M15).

The formulas (M1) to (M3) are formulas indicating an electrode reaction, and are called Butler-Volmer formulas. In the equation (M1), the exchange current density i ₀ is given as a function of the lithium ion concentration at the interface of the active material (refer to Non-Patent Document 1 for details). Α _a represents the transfer coefficient of the electrode reaction at the positive electrode, and α _c represents the transfer coefficient of the electrode reaction at the negative electrode. The expression (M2) gives η in the expression (M1), and the expression (M3) gives U in the expression (M2).

Equations (M4) to (M6) represent the law of conservation of lithium ions in the electrolyte. The equation (M5) shows the definition of the effective diffusion coefficient in the electrolyte, and the equation (M6) shows that the reaction current j ^Li is the active material surface area a _s per unit volume of the electrode and the transport current shown in the equation (M1). It indicates that given by the product of the density / i _n. The volume integral of the reaction current j ^{Li over} the entire electrode corresponds to the current I flowing through the battery cell.

Equations (M7) and (M8) indicate the conservation law of lithium ions in the solid layer. (M7) equation represents the diffusion equation in an active material in the sphere shows (M8) expression per electrode unit volume active material surface area a _s.

  Expressions (M9) to (M11) are based on the law of conservation of charge in the electrolyte. These equations show the potential in the electrolyte.

The equation (M10) represents the effective ionic conductivity κ ^eff and the equation (M11) represents the diffusion conductivity coefficient κ _D ^eff in the electrolytic solution.

  Equations (M12) and (M13) are based on the law of conservation of charge in the active material. These formulas show the potential in the solid layer.

  Equations (M14) and (M15) are based on the thermal energy conservation law. By these equations, it becomes possible to analyze a local temperature change inside the battery due to a charge / discharge phenomenon.

  Since the battery model formulas (M1) to (M15) are based on Non-Patent Document 1, Non-Patent Document 1 is used for detailed description of each formula.

  The battery model parameters shown in FIG. 4 can be obtained by combining battery model expressions (M1) to (M15). That is, the unknown equation among the battery model parameters shown in FIG. 4 is obtained by sequentially solving the equation (M1) to (M15) so that the boundary condition is satisfied at each point in the active material and the electrolytic solution. Things can be calculated sequentially. In this case, which of the battery model parameters shown in FIG. 4 is a known amount and which is an unknown amount can be arbitrarily determined in the theory of numerical analysis. The lithium ion concentration in each active material is a function of the radius r of the active material, and the lithium ion concentration is treated as uniform in the circumferential direction.

The battery state quantity estimation unit 26 obtains the actual battery state quantity as the battery state quantity BS based on the battery current measurement value Ib, the battery voltage measurement value Vb, the battery temperature measurement value Tb, and the battery model parameter. Here, the battery state quantity BS includes, among the battery model parameters, the potential φ _s in the solid layer, the potential φ _e in the electrolytic solution, the lithium ion concentration c _s of the active material, the lithium ion concentration c _e of the electrolytic solution, and It is a physical stoichiometry consisting of a set of lithium ion concentrations c _se at the active material interface.

The battery state quantity estimation unit 26 obtains a battery state quantity BS (φ _s , φ _e , c _s , c _e , and c _se ) based on the battery model equations (M1) to (M15), and the battery state quantity BS Is output to the chargeable power prediction unit 28.

  On the other hand, the charge allowable voltage generation unit 30 determines a charge voltage limit value Vc for charging at a constant voltage, and outputs it to the chargeable power prediction unit 28. Here, the charge voltage limit value refers to an arithmetic value set for calculation by the chargeable power prediction unit 28.

  FIG. 5A shows an example of the waveform of the charging voltage limit value. In FIG. 5A, the horizontal axis indicates time, and the vertical axis indicates voltage. The charging voltage limit value shown in FIG. 5A increases from the battery voltage measured value Vb to the charging voltage limit value Vc at the reference time t0.

The chargeable power prediction unit 28 sets the battery state quantity BS and the battery temperature measurement value Tb as initial values, and changes the current I flowing through the battery 10 over time when the constant voltage charging is performed with the charge voltage limit value Vc (M1). ) Formula to (M15) Formula is used for prediction. At this time, a well-known physical relationship established among the charge voltage limit value, the potential φ _s in the solid layer, the reaction current j ^Li , and the electron conductivity σ in the solid layer is used. The current I is obtained based on the volume integration of the reaction current j ^{Li over} the entire electrode. The chargeable power prediction unit 28 obtains a chargeable power characteristic indicating a change over time of the chargeable power based on the obtained current I and the charge voltage limit value.

  FIG. 5B shows an example of the chargeable power characteristic obtained by the chargeable power prediction unit 28 based on the charge voltage limit value shown in FIG. In FIG. 5B, the horizontal axis indicates time, and the vertical axis indicates chargeable power. In this way, when charging at a constant voltage is considered, the chargeable power becomes maximum immediately after the start of charging and decreases with time. The chargeable power prediction unit 28 outputs a value given by the chargeable power characteristic as the charge power limit value Win.

  The power control device 12 charges the battery 10 so as not to exceed the charging power limit value Win. As a result, the battery 10 can be charged with as much power as possible according to the battery state quantity BS and the battery temperature measurement value Tb of the battery 10.

  In the configuration illustrated in FIG. 2, the charge power limit value Win may be a value that is greater than or equal to the allowable power of the circuit that charges the battery 10. Therefore, a power limit value setting unit 32 may be provided as in the second embodiment shown in FIG. The same components as those shown in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.

  The power limit value setting unit 32 obtains a charge power limit value based on the chargeable power characteristic data output from the chargeable power prediction unit 28. Here, it is assumed that the power limit value setting unit 32 stores in advance a predetermined Win calculation time tc for obtaining the charge power limit value. The power limit value setting unit 32 refers to the chargeable power characteristic data, and obtains the chargeable power when the Win calculation time tc has elapsed from the reference time t0 as the charge power limit value Win. The power limit value setting unit 32 outputs the charging power limit value Win to the power control device 12. In the example of FIG. 5B, the value on the vertical axis when the time tc for Win calculation elapses from the reference time t0 is obtained as the charging power limit value Win. As a result of such processing, an estimated value of power that can be continuously charged for a time tc at a constant voltage Vc with the current actual battery state quantity BS as an initial value is obtained as the charge power limit value Win.

  The power limit value calculation device 24 performs a process for obtaining the charge power limit value Win every predetermined time td, and outputs the charge power limit value Win to the power control device 12 at a time interval td. The power control device 12 charges the battery 10 so as not to exceed the charging power limit value Win.

  The value indicated by the chargeable power characteristic increases as the charge voltage limit value Vc increases, and the required charge power limit value Win increases. Further, as shown in FIG. 5B, the value indicated by the chargeable power characteristic increases as the Win calculation time tc is shortened, and the required charging power limit value Win increases. The time required to charge the battery to a predetermined charging depth is shorter as the charging power is larger. On the other hand, the life of the battery defined by a period or the like in which a charge capacity equal to or greater than a predetermined value can be maintained becomes shorter as the charging power is larger. Therefore, the charging voltage limit value Vc and the Win calculation time tc are preferably determined based on experiments in consideration of the life of the battery 10 and the quickness of the charging time.

  FIG. 7 shows the configuration of the power limit value calculation device 24 according to the third embodiment. In this embodiment, the charge allowable voltage generation unit 54 obtains the charge voltage limit value Vc based on the battery state quantity BS. Then, the obtained charging voltage limit value Vc is output to the chargeable power prediction unit 28. The same components as those of the second embodiment shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

The battery state quantity estimation unit 26 obtains the charge depth of the battery 10 based on the battery state quantity BS. Then, the battery state quantity BS and the charging depth are output to the chargeable power prediction unit 28 and the charge allowable voltage generation unit 54. Here, the charge depth refers to an amount indicating the ratio of the charge amount currently charged to the charge amount at the time of full charge. In the electrochemical model, the charging depth can be obtained from the lithium ion concentration c _S in the active material 40 of the negative electrode 34.

  The charge allowable voltage generation unit 54 stores a charge depth vs. voltage limit value table in which the charge depth and the charge voltage limit value Vc are associated with each other. The charge allowable voltage generation unit 54 refers to the charge depth vs. voltage limit value table and obtains the charge voltage limit value Vc corresponding to the obtained charge depth.

  FIG. 8 is a graph showing an example of the relationship indicated by the charging depth versus voltage limit value table. The horizontal axis of FIG. 8 indicates the charging depth, and the vertical axis indicates the charging voltage limit value Vc. In the example of FIG. 8, when the charging depth is less than the predetermined threshold SOCt1, the charging voltage limit value Vc is constant with respect to the change in the charging depth. On the other hand, when the charging depth is equal to or greater than the predetermined threshold SOCt1, the charging depth is increased and the charging voltage limit value Vc is decreased.

  When there is a relationship of SOCt1 <SOC1 <SOC2 <SOC3 between the charging depths SOC1, SOC2 and SOC3, the relationship of the charging voltage limit values Vc1, Vc2 and Vc3 corresponding to each is Vc1> Vc2> Vc3. As a result, the time waveforms of the charge voltage limit value output by the charge allowable voltage generation unit 54 are as shown by time waveforms 56-1, 56-2, and 56-3 in FIG. 9A, respectively. And the chargeable power characteristic calculated | required in the chargeable power prediction part 28 corresponding to the time waveforms 56-1, 56-2, and 56-3 of Fig.9 (a) is respectively shown in FIG.9 (b). Characteristics 58-1, 58-2, and 58-3 are obtained. From the characteristics 58-1, 58-2, and 58-3, charging power limit values Win1, Win2, and Win3 are obtained for the common Win calculation time tc, respectively. These charging power limit values have a relationship of Win1> Win2> Win3.

  Thus, in the present embodiment, when the charge depth becomes equal to or greater than the predetermined threshold, the charge allowable voltage generation unit 54 determines the charge voltage limit value Vc so that the value decreases as the charge depth increases. As a result, when the charging depth becomes equal to or greater than a predetermined threshold, the charging power limit value Win can be reduced as the charging depth increases.

  In general, batteries often do not require quick charging when the charging depth is large. Therefore, according to the present embodiment, when the charging depth is equal to or greater than the predetermined threshold value, the charging power can be reduced and the electrical burden on the battery 10 can be reduced.

  Here, the processing using the charging depth has been described, but the same processing can be performed using other amounts indicating the charging state of the battery 10 that can be obtained from the battery state amount BS. Moreover, it is good also as a structure which does not use the electric power limit value setting part 32 similarly to 1st Example shown in FIG.

  FIG. 10 shows the configuration of the power limit value calculation device 24 according to the fourth embodiment. In this embodiment, the calculation time adjustment unit 60 calculates the Win calculation time tc based on the battery state quantity BS and outputs it to the power limit value setting unit 32. The same components as those of the second embodiment shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

  The battery state quantity estimation unit 26 outputs the battery state quantity BS and the charging depth of the battery 10 to the chargeable power prediction unit 28 and the calculation time adjustment unit 60.

  The calculation time adjustment unit 60 stores a charging depth versus calculation time table in which the charging depth and the Win calculation time tc are associated with each other. The calculation time adjustment unit 60 refers to the charging depth vs. calculation time table, obtains the Win calculation time tc corresponding to the obtained charging depth, and outputs it to the power limit value setting unit 32. The power limit value setting unit 32 obtains the charge power limit value Win corresponding to the Win calculation time tc output from the calculation time adjustment unit 60.

  FIG. 11 is a graph showing an example of the relationship indicated by the charging depth versus calculation time table. In FIG. 11, the horizontal axis indicates the charging depth, and the vertical axis indicates the time tc for Win calculation. In the example of FIG. 11, when the charging depth is less than the predetermined threshold SOCt2, the Win calculation time tc is constant with respect to the change in the charging depth. On the other hand, when the charging depth is equal to or greater than the predetermined threshold SOCt2, the charging depth increases and the Win calculation time tc is lengthened.

  When there is a relationship of SOCt2 <SOC1 <SOC2 <SOC3 between the charging depths SOC1, SOC2 and SOC3, the relationship of the Win calculation times tc1, tc2 and tc3 corresponding to each is tc1 <tc2 <tc3. As a result, the charging power limit values obtained corresponding to the Win calculation time output from the calculation time adjustment unit 60 are Win1, Win2, and Win3, respectively, as shown in FIG. These charging power limit values have a relationship of Win1> Win2> Win3.

  As described above, in this embodiment, when the charging depth is equal to or greater than the predetermined threshold, the time tc for calculating the Win is calculated so that the time indicated by the charging depth increases. As a result, when the charging depth becomes equal to or greater than a predetermined threshold, the charging power limit value Win can be reduced as the charging depth increases. Therefore, as in the third embodiment, when the charging depth is equal to or greater than a predetermined threshold, the charging power can be reduced and the electrical burden on the battery 10 can be reduced. Here, the processing using the charging depth has been described, but the same processing can be performed using other amounts indicating the charging state of the battery 10 that can be obtained from the battery state amount BS.

  FIG. 13 shows the configuration of the power limit value calculation device 24 according to the fifth embodiment. This embodiment is a combination of the charge allowable voltage generation unit 54 in the third embodiment and the calculation time adjustment unit 60 in the fourth embodiment. The same components as those of the third embodiment shown in FIG. 7 and the components of the fourth embodiment shown in FIG.

  In the present embodiment, when the charging depth is equal to or greater than a predetermined threshold, the charging voltage limit value Vc is determined so that the value decreases as the charging depth increases. Furthermore, in the present embodiment, when the charging depth is equal to or greater than a predetermined threshold, the Win calculation time tc is determined so that the time indicated by the charging depth increases. As a result, when the charging depth becomes equal to or greater than a predetermined threshold, the charging power limit value Win can be reduced as the charging depth increases. The combination of the allowable charging voltage generation unit 54 and the calculation time adjustment unit 60 can increase the effect of reducing the electrical burden on the battery 10 when the charging depth is equal to or greater than a predetermined threshold.

  FIG. 14 shows a configuration of a vehicle power control system according to another embodiment of the present invention. The same components as those of the vehicle power control system of FIG. 1 are denoted by the same reference numerals and description thereof is omitted. The battery diagnosis / power limit value calculation device 62 changes the current flowing through the battery 10 in the battery diagnosis mode, and determines the battery model parameters of the battery 10, the degree of deterioration of the battery 10, etc. based on the change in the output voltage of the battery 10. Ask. Then, the charging power limit value Win is obtained from the equations (M1) to (M15) using the obtained battery model parameters, the degree of deterioration, and the like.

FIG. 15 shows the configuration of the battery diagnosis / power limit value calculation device 62 according to the first embodiment. The same components as those of the power limit value calculation device 24 shown in FIG. This embodiment includes a battery characteristic determination unit 66 that measures the exchange current density i ₀ and the diffusion coefficient D _s of the battery 10.

  A mode changeover switch 64 is connected to each end of the battery 10. The mode switch 64 connects the battery 10 to the power control device 12 in the normal travel mode. On the other hand, in the battery diagnosis mode, the battery 10 is connected to the battery diagnosis / power limit value calculation device 62. In the battery diagnosis mode, the battery diagnosis / power limit value calculation device 62 controls the current flowing through the battery 10 so that the time waveform of the current flowing through the battery 10 becomes, for example, the time waveform shown in FIG. . In FIG. 16A, the horizontal axis indicates time, and the vertical axis indicates the charging current flowing through the battery 10. The current time waveform in FIG. 16A changes from the initial value I1 at which the charging current of the battery 10 is at the diagnostic value I2 at time t1, and then returns to the initial value I1 after maintaining the diagnostic current value I2 until time t2. FIG. 16B shows an example of a time waveform of the battery voltage measurement value Vbp at this time. The horizontal axis represents time, and the vertical axis represents the measured battery voltage value Vbp.

The battery characteristic determination unit 66 is based on each time change of the battery voltage measurement value Vbp, the battery current measurement value Ibp, and the battery temperature measurement value Tbp when the current of the battery 10 changes as shown in FIG. Among the battery model parameters listed in FIG. 4, the exchange current density i ₀ and the diffusion coefficient D _s are obtained.

The battery characteristic determination unit 66 outputs the obtained exchange current density i ₀ and the diffusion coefficient D _s to the battery state quantity estimation unit 26 and the chargeable power prediction unit 28.

The battery state quantity estimation unit 26 updates the exchange current density i ₀ and the diffusion coefficient D _s previously used to the exchange current density i ₀ and the diffusion coefficient D _s newly given from the battery characteristic determination unit 66, The battery state quantity BS is obtained. The chargeable power prediction unit 28 updates the exchange current density i ₀ and the diffusion coefficient D _s previously used to the exchange current density i ₀ and the diffusion coefficient D _s newly given from the battery characteristic determination unit 66, Obtain chargeable power characteristics.

According to this embodiment, even when the exchange current density i ₀ and the diffusion coefficient D _s of the battery 10 changes due to aging or the like, suitably using an exchange current density i ₀ and the diffusion coefficient D _s after the change Charge control can be performed.

  The processing in the battery diagnosis mode is preferably performed when the vehicle is stopped with the vehicle power control system operable, such as when the ignition is on.

  FIG. 17 shows the configuration of the battery diagnosis / power limit value calculation device 62 according to the second embodiment. In this embodiment, the deterioration degree estimation unit 68 obtains the deterioration degree of the battery 10 based on the battery current measurement value Ibp, the battery voltage measurement value Vbp, and the battery temperature measurement value Tbp in the battery diagnosis mode, and generates a chargeable voltage. To the unit 30. Charge allowable voltage generation unit 30 determines charge voltage limit value Vc based on the degree of deterioration obtained by deterioration degree estimation unit 68. The same components as those of the first embodiment shown in FIG. 15 are denoted by the same reference numerals, and the description thereof is omitted.

  The battery diagnosis / power limit value calculation device 62 controls the current flowing through the battery 10 so that the time waveform of the current flowing through the battery 10 becomes, for example, the time waveform shown in FIG. Degradation degree estimation unit 68 uses the battery voltage measurement value Vbp, battery current measurement value Ibp, and battery temperature measurement value Tbp when the current of battery 10 changes as shown in FIG. A degree of degradation of 10 is obtained. Here, the deterioration degree of the battery 10 can be evaluated by, for example, SOH (State Of Health). SOH is defined as the ratio of the current chargeable discharge amount at full charge to the chargeable charge amount (full chargeable charge amount) when the battery is fully charged when new. The SOH can be obtained by referring to a table in which the relationship between the value of the battery model parameter and the SOH is determined by experiments or the like.

  The allowable charge voltage generation unit 30 stores a deterioration degree versus voltage limit value table in which the deterioration degree and the charge voltage limit value Vc are associated with each other. The allowable charge voltage generation unit 30 refers to the deterioration level vs. voltage limit value table and determines the charge voltage limit value Vc corresponding to the determined deterioration level.

  FIG. 18 is a graph showing an example of the relationship indicated by the deterioration degree vs. voltage limit value table. The horizontal axis in FIG. 18 indicates the degree of deterioration, and the vertical axis indicates the charging voltage limit value Vc. In the example of FIG. 18, when the deterioration level is less than the predetermined threshold value Ht1, the charging voltage limit value Vc is constant with respect to the change in the deterioration level. On the other hand, when the deterioration level is equal to or greater than the predetermined threshold value Ht1, the deterioration level increases and the charging voltage limit value Vc is decreased.

  When there is a relationship of Ht1 <H4 <H5 <H6 between the degradation levels H4, H5, and H6, the relationship between the charge voltage limit values Vc4, Vc5, and Vc6 corresponding to each is Vc4> Vc5> Vc6. As a result, the waveforms of the charge voltage limit value Vc output by the charge allowable voltage generation unit 30 are as shown by time waveforms 70-4, 70-5, and 70-6 in FIG. 19A, respectively. And the chargeable power characteristic calculated | required in the chargeable power prediction part 28 corresponding to the time waveforms 70-4, 70-5, and 70-6 of Fig.19 (a) is respectively shown in FIG.19 (b). Characteristics 72-4, 72-5, and 72-6 are obtained. From the characteristics 72-4, 72-5, and 72-6, charging power limit values Win4, Win5, and Win6 are obtained for the common Win calculation time tc, respectively. These charging power limit values have a relationship of Win4> Win5> Win6.

  As described above, in this embodiment, when the deterioration level is equal to or greater than the predetermined threshold value, the charging voltage limit value Vc is determined so that the larger the deterioration level, the smaller the value. As a result, when the degree of deterioration exceeds a predetermined threshold, the charging power limit value Win can be reduced as the degree of deterioration increases.

  It is preferable to extend the life of the battery as much as possible without performing quick charging when the degree of deterioration increases. According to the present embodiment, when the degree of deterioration is equal to or greater than a predetermined threshold, the charging power can be reduced and the life of the battery 10 can be extended.

  15 and 17, the battery diagnosis / power limit value calculation device 62 according to the first and second embodiments is similar to the power limit value calculation device 24 shown in FIG. It is good also as a structure which does not use 32.

  FIG. 20 shows the configuration of the battery diagnosis / power limit value calculation device 62 according to the third embodiment. In this embodiment, the deterioration degree estimation / calculation time adjustment unit 74 obtains the Win calculation time tc based on the battery voltage measurement value Vbp, the battery current measurement value Ibp, and the battery temperature measurement value Tbp in the battery diagnosis mode. To the power limit value setting unit 32. The same components as those of the first embodiment shown in FIG. 15 are denoted by the same reference numerals, and the description thereof is omitted.

  The battery diagnosis / power limit value calculation device 62 controls the current flowing through the battery 10 so that the time waveform of the current flowing through the battery 10 in the battery diagnosis mode becomes, for example, the time waveform shown in FIG. Deterioration degree estimation / calculation time adjustment unit 74 performs each time of battery voltage measurement value Vbp, battery current measurement value Ibp, and battery temperature measurement value Tbp when the current of battery 10 changes as shown in FIG. Based on the change, the degree of deterioration of the battery 10 is obtained.

  The degradation degree estimation / calculation time adjustment unit 74 stores a degradation degree versus computation time table in which the degradation degree and the Win computation time tc are associated with each other. The degradation level estimation / calculation time adjustment unit 74 refers to the degradation level vs. computation time table, obtains a Win computation time tc corresponding to the obtained degradation level, and outputs it to the power limit value setting unit 32. The power limit value setting unit 32 obtains the charge power limit value Win corresponding to the Win calculation time tc output from the calculation time adjustment unit 60.

  FIG. 21 is a graph showing an example of the relationship indicated by the deterioration degree versus calculation time table. In FIG. 21, the horizontal axis represents the degree of deterioration, and the vertical axis represents the time tc for Win calculation. In the example of FIG. 21, when the deterioration level is less than the predetermined threshold value Ht2, the Win calculation time is constant with respect to the change in the deterioration level. On the other hand, when the degree of deterioration is equal to or greater than the predetermined threshold value Ht2, the degree of deterioration increases and the Win calculation time is lengthened.

  When there is a relationship of Ht2 <H4 <H5 <H6 between the degradation levels H4, H5 and H6, the relationship of the Win calculation times tc4, tc5 and tc6 corresponding to each is tc4 <tc5 <tc6. As a result, the charging power limit values obtained corresponding to the Win calculation time tc output from the deterioration level estimation / calculation time adjustment unit 74 are Win4, Win5, and Win6, respectively, as shown in FIG. These charging power limit values have a relationship of Win4> Win5> Win6.

  As described above, in this embodiment, when the deterioration level is equal to or greater than the predetermined threshold value, the Win calculation time tc is determined so that the time indicated by the deterioration level increases as the deterioration level increases. As a result, when the degree of deterioration exceeds a predetermined threshold, the charging power limit value Win can be reduced as the degree of deterioration increases. As a result, as in the second embodiment, when the degree of deterioration is greater than or equal to a predetermined threshold, the charging power can be reduced and the life of the battery 10 can be extended.

  FIG. 23 shows the configuration of the battery diagnosis / power limit value calculation device 62 according to the fourth embodiment. This power limit value calculation device is a combination of the deterioration level estimation unit 68 in the second embodiment and the deterioration level estimation / calculation time adjustment unit 74 in the third embodiment. The same components as those of the second embodiment shown in FIG. 17 and the components of the third embodiment shown in FIG.

  In the present embodiment, when the deterioration level is equal to or greater than a predetermined threshold, the charging voltage limit value is determined such that the larger the deterioration level, the smaller the value. Furthermore, in the present embodiment, when the deterioration level is equal to or greater than a predetermined threshold, the Win calculation time tc is determined so that the time indicated by the deterioration level increases as the deterioration level increases. As a result, when the degree of deterioration exceeds a predetermined threshold, the charging power limit value Win can be reduced as the degree of deterioration increases. By combining the deterioration level estimation / voltage limit value setting unit 68 and the deterioration level estimation / calculation time adjustment unit 74, the effect of extending the life of the battery 10 can be increased.

  The fourth example of the power limit value calculating device 24 according to the first embodiment and the second example of the battery diagnosis / power limit value calculating device 62 according to the second embodiment can be combined. A battery diagnosis / power limit value calculation device 62 based on this combination is shown in FIG. The same components as those shown in FIGS. 10 and 17 are denoted by the same reference numerals and description thereof is omitted.

  The battery diagnosis / power limit value calculation device 62 obtains the charge voltage limit value Vc by the deterioration degree estimation unit 68 and the charge allowable voltage generation unit 30, and adjusts the Win calculation time tc by the calculation time adjustment unit 60. It is.

  Further, the third example of the power limit value calculating device 24 according to the first embodiment and the third example of the battery diagnosis / power limit value calculating device 62 according to the second embodiment can be combined. is there. A battery diagnosis / power limit value calculation device 62 based on this combination is shown in FIG. The same components as those shown in FIGS. 7 and 20 are denoted by the same reference numerals and description thereof is omitted.

  The battery diagnosis / power limit value calculation device 62 obtains a charge voltage limit value by the charge allowable voltage generation unit 54 and adjusts the Win calculation time tc by the deterioration degree estimation / calculation time adjustment unit 74.

  DESCRIPTION OF SYMBOLS 10 Battery, 12 Power control apparatus, 14 Motor generator, 16 Operation part, 18 Current sensor, 20 Voltage sensor, 22 Temperature sensor, 24 Power limit value calculating apparatus, 26 Battery state quantity estimation part, 28 Chargeable power prediction part, 30 , 54 Charging allowable voltage generating unit, 32 Power limit value setting unit, 34 Negative electrode, 36 Positive electrode, 38 Separator, 40, 42 Active material, 44 Negative electrode collector, 46 Positive electrode collector, 48 Negative electrode terminal, 50 Positive electrode terminal, 52 External circuit, 56-1 to 56-3, 70-4 to 70-6 Charging voltage limit value time waveform, 58-1 to 58-3, 72-4 to 72-6 chargeable power characteristics, 60 arithmetic time adjustment unit, 62 Battery diagnosis / power limit value calculation device, 64 mode changeover switch, 66 battery characteristic determination unit, 68 degradation level estimation unit, 74 degradation level estimation / calculation Time adjustment unit.

Claims (8)

A sensor for measuring a current flowing through a battery for supplying vehicle driving power , an output voltage of the battery, and a temperature of the battery ;
A battery state quantity estimation unit for obtaining a battery state quantity including a battery model parameter of the battery from a battery model formula for the battery based on each measurement result of the sensor ;
A charge allowable voltage generation unit that sets a charging voltage limit value in order to obtain charging power to the battery when charging the battery at a constant voltage as chargeable power when charging the battery based on the battery model formula When,
A chargeable power prediction unit for obtaining a change in charging power to the battery over time when charging the battery at a constant voltage with a voltage of the charging voltage limit value as a chargeable power characteristic based on the battery model formula, Based on the charge voltage limit value and the battery state quantity , a chargeable power prediction unit for obtaining the chargeable power characteristic ,
With
The chargeable based on power characteristics, actually the battery charge power limit value calculation device according to claim Rukoto calculated charging power limit value in charging the. In the charging power limit value calculation device according to claim 1,
The chargeable power characteristic is a characteristic that the chargeable power increases and becomes maximum after the start of charging, and then decreases with time.
The charging power limit value calculation unit, on the basis of the chargeable power characteristics, a rechargeable power observed when a predetermined time has elapsed from the reference time corresponding to the initial time on calculation by the battery model equation, the limit charging power A charging power limit value calculation device comprising a power limit value setting unit obtained as follows. In the charging power limit value calculation device according to claim 2,
The battery state quantity estimation unit obtains a charging depth of the battery based on the battery state quantity,
The charging power limit value calculation unit, charging power limit value calculation apparatus characterized by obtaining Bei between adjuster when as stipulated how long have long as the obtained state of charge is larger as the predetermined time. In the charging power limit value calculation device according to claim 2,
A deterioration degree estimation unit for obtaining a deterioration degree of the chargeability of the battery, and obtaining a deterioration degree represented by a change with time of a charge amount that can be discharged at full charge ;
And during adjustment portion when the amount of time as has long large deterioration degree determined by said deterioration degree estimation portion shall be determined as the predetermined time,
Charge power limit value calculation apparatus characterized by obtaining Bei a. In the charging power limit value calculation device according to claim 4,
The charge allowable voltage generator is
Charge power limit value calculation unit, characterized in that you set a smaller value the larger the deterioration degree determined by said deterioration degree estimation portion as the charging voltage limit value. In the charging power limit value calculation device according to any one of claims 1 to 3,
A deterioration degree of the charge capacity of the previous SL cell includes a deterioration degree estimation unit for obtaining a degradation degree represented by the aging of the fully charged during discharge charge quantity,
The charge allowable voltage generator is
Charge power limit value calculation unit, characterized in that you set a smaller value the larger the deterioration degree determined by said deterioration degree estimation portion as the charging voltage limit value. In the charging power limit value calculation device according to any one of claims 1 to 4,
The battery state quantity estimation unit obtains a charging depth of the battery based on the battery state quantity,
The chargeable voltage generator, before charging power limit value calculation unit, characterized in that you set the smaller value as KiTakashi electrostatic depth is greater as the charge voltage limit. In the charging power limit value calculation device according to any one of claims 1 to 7,
A battery current controller for changing the current flowing through the battery;
A battery characteristic determination unit that obtains a characteristic constant including an exchange current density and a diffusion coefficient for the battery based on a change in the output voltage of the battery with respect to a current change by the battery current control unit;
Equipped with a,
The battery state quantity estimator is
In addition to the measurement result of the sensor, it obtains the battery state quantity based on the characteristic constants obtained by said battery characteristic determining unit,
The rechargeable power prediction unit
Wherein in addition to the charging voltage limit value and the battery state quantity, the battery characteristic determining unit charging power limit value calculation unit, wherein the mel determined the chargeable power characteristics based on characteristics constant determined by.

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