JP2005326377A - Arithmetic processing unit for power quantity of charge accumulating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately grasp an internal condition of a charge accumulating device, and to precisely find a power quantity all the time even under various conditions in practical use. <P>SOLUTION: The power quantity P is found by composition of a power quantity PV based on a release voltage and a power quantity PC based on a current weighted with a weight w changed from time to time in response to a using condition of a battery. A computed value is thereby precluded from being fluctuated by fluctuation of a load under the practical using condition, and precision of the computed value is thereby precluded from getting low by fluctuation of a sampling data, so as to obtain the power quantity reflected accurately with the internal condition of the battery. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power amount calculation device for a power storage device that calculates a power amount that can be input and output in a power storage device such as a secondary battery or an electrochemical capacitor.

  In recent years, energy storage devices such as secondary batteries such as nickel metal hydride batteries and lithium ion batteries, and electrochemical capacitors such as electric double layer capacitors have been reduced in size and weight, and energy density has increased. It is actively used as a power source for automobiles.

  The energy that can be used in such a power storage device can be evaluated by calculating the input / output possible power amount of the power storage device, and is mounted on, for example, an electric vehicle or a hybrid vehicle based on the calculated power amount. Power supply to the motor, drive torque control, etc. can be executed precisely.

  For this reason, various techniques have been proposed in the past for accurate calculation of the power amount. For example, Patent Document 1 discloses a battery discharge based on a DC current I and a DC voltage V supplied from the battery. A technique is disclosed in which an IV straight line representing characteristics is calculated, and an outputable power amount is calculated based on the IV straight line and the minimum guaranteed voltage of the battery.

  Further, in Patent Document 2, a dischargeable amount (that is, an outputable power amount) as an energy amount that can be output from a battery is obtained by referring to a map for each temperature as a battery discharge current or a terminal voltage and a parameter, A technique for obtaining a chargeable amount (that is, an inputable power amount) as an energy amount that can be input to the battery by subtracting the dischargeable amount from the total capacity of the battery.

Further, Patent Document 3 calculates the input / output possible power (input / output possible power amount) by performing regression calculation on the voltage / current characteristics of the assembled battery, and calculates the calculated input / output possible power to variations in internal resistance for each cell. A technique for correcting in consideration of the above is disclosed.
JP-A-9-171063 Japanese Patent Laid-Open No. 2002-14147 JP 2002-272011 A

  However, in the techniques disclosed in Patent Document 1 and Patent Document 2, the amount of power is calculated using the measured voltage as it is, and the internal resistance of the battery is not taken into consideration. For this reason, the calculated power amount does not necessarily accurately grasp the state of the battery itself, and if the load (current value) fluctuates greatly while using the battery, the power value may fluctuate greatly. There is. Moreover, the technique of Patent Document 1 does not mention the amount of power that can be input during battery charging, and the range of application is limited, such as an electric vehicle that runs only with a motor, and charging and discharging continue. It is difficult to apply to hybrid vehicles.

  The technique disclosed in Patent Document 3 is effective for battery protection because it performs correction based on the cell having the highest internal resistance. However, when the number of cells is large, the overall state is shown. It is difficult to grasp. Furthermore, in the technique of Patent Document 3, since the open circuit voltage is estimated from the regression line of the VI characteristic obtained from the sampling data of the voltage V and the current I during discharge, when the load fluctuates greatly in a short time, For example, when a series hybrid vehicle is in a driving state where acceleration / deceleration is severe, the influence of the delay component of the battery voltage cannot be ignored, and it is difficult to accurately estimate the open circuit voltage.

  In other words, the conventional techniques shown in each patent document do not necessarily calculate the power amount after accurately grasping the internal state of the power storage device, but the power amount is not changed by the load variation under actual use conditions. There are problems that the calculated value fluctuates and the accuracy of the calculated value decreases due to variations in sampling data.

  The present invention has been made in view of the above circumstances, and it is possible to accurately grasp the internal state of an electricity storage device and to always obtain a highly accurate power amount even under various conditions in actual use. The object is to provide a quantity calculation device.

  To achieve the above object, a power amount calculation device for an electricity storage device according to the present invention calculates a first input power amount and a first output power amount based on an internal impedance and an open-circuit voltage of the electricity storage device. A first computing means; a second computing means for computing a second inputtable power amount and a second outputable power amount based on the internal impedance and charge / discharge current of the power storage device; The input possible power amount and the second input possible power amount are weighted and synthesized using a weight set in accordance with the usage state of the power storage device, and the input possible power amount of the power storage device is calculated. The third outputable power amount and the second outputable power amount are weighted and synthesized using the weights, and the outputable power amount of the power storage device is calculated. Characterized in that an arithmetic unit.

  The first inputable power amount can be calculated using the internal impedance, open voltage, and upper limit voltage of the power storage device, and the first outputable power amount is calculated using the internal impedance, open voltage, and lower limit voltage of the power storage device. Can be used to calculate. In addition, the second input possible power amount can be calculated using the internal impedance of the power storage device, the moving average value of the charge / discharge current, and the input possible power amount before one calculation cycle. The amount can be calculated using the internal impedance of the electricity storage device, the moving average value of the charge / discharge current, and the outputable power amount one calculation cycle before.

  The weight is preferably set based on the moving average value of the charge / discharge current of the power storage device, and the internal impedance is calculated based on the moving average value of the charge / discharge current of the power storage device and the temperature of the power storage device. Is desirable.

  The power storage device power amount calculation apparatus according to the present invention calculates the power amount after accurately grasping the internal state of the power storage device, and therefore always obtains a highly accurate power amount even under various conditions in actual use. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 relate to an embodiment of the present invention, FIG. 1 is a system configuration diagram showing an example of application to a hybrid vehicle, FIG. 2 is a block diagram showing an algorithm for calculating a power amount, and FIG. 3 is an equivalent circuit model. FIG. 4 is a flowchart of power amount calculation processing, FIG. 5 is an explanatory diagram of an impedance table, FIG. 6 is an explanatory diagram of a remaining capacity table, FIG. 7 is an explanatory diagram of a weight table, and FIG. FIG. 9 is an explanatory diagram showing the calculation result of the combined input possible power amount, FIG. 10 is an explanatory diagram showing the dischargeable amount based on the open circuit voltage, and FIG. 11 is the calculation result of the combined output possible power amount. It is explanatory drawing which shows.

  FIG. 1 shows an example in which the present invention is applied to a hybrid vehicle (HEV) that travels using both an engine and a motor. In the figure, reference numeral 1 denotes a HEV power supply unit. The power supply unit 1 includes, for example, a battery 2 configured by connecting a plurality of battery packs in which a plurality of cells are sealed in series as power storage devices, calculation of the remaining capacity and power amount of the battery 2, and cooling of the battery 2. And a calculation unit (calculation ECU) 3 that performs energy management such as charge control, abnormality detection, and protection operation at the time of abnormality detection are packaged in one casing.

  In this embodiment, a lithium ion secondary battery will be described as an example of a power storage device, but the method of the present invention can also be applied to an electrochemical capacitor and other secondary batteries.

  The arithmetic ECU 3 is composed of a microcomputer or the like, and the terminal voltage V of the battery 2 measured by the voltage sensor 4, the charge / discharge current I of the battery 2 measured by the current sensor 5, and the temperature (cell) of the battery 2 measured by the temperature sensor 6. Based on (temperature) T, the remaining capacity SOC (t) indicated by the state of charge (SOC) of the battery 2 and the power amount P indicated by the maximum power that can be input / output in the battery 2 at a predetermined time t. Calculate (t). Note that the remaining capacity SOC (t−1) and the power amount P (t−1) before one calculation cycle are input to the calculation ECU 3 as base values in the cyclic calculation.

  The remaining capacity SOC and the power amount P calculated by the calculation ECU 3 are output to the HEV control electronic control unit (HEV control ECU) 10 via, for example, CAN (Controller Area Network) communication, etc., and display of the control state and the control amount Is used as basic data for determining. The HEV control ECU 10 is similarly composed of a microcomputer or the like, and performs HEV operation and other necessary control based on a command from the driver. That is, the HEV control ECU 10 detects the state of the vehicle based on signals from the power supply unit 1 and signals from sensors and switches (not shown), and converts the DC power of the battery 2 into AC power to drive the motor 15. Starting with the inverter 20, the engine 30 connected to the motor 15, an automatic transmission (not shown), and the like are controlled via a dedicated control unit or directly.

  For example, from the remaining capacity SOC calculated by the calculation ECU 3, display data for battery capacity and warning data for warning the battery capacity decrease are generated and used as battery information for the driver. Further, from the power amount P calculated by the arithmetic ECU 3, the driving torque that can be output from the motor 15, the charge / regeneration amount by the power generation of the motor 15, the limiter value for limiting the output of the battery 2, and the like are calculated. It is used as a direct parameter for calculating the control amount required for operation.

  The calculation of the power amount P in the calculation ECU 3 is executed according to the calculation algorithm shown in FIG. In this calculation algorithm, parameters measurable by the battery 2, that is, the terminal voltage V, the current I, and the temperature T are used, and the power amount PV based on the open voltage Vo of the battery 2 and the power amount PC based on the current I of the battery 2 are used. Are calculated in parallel, and a value obtained by weighting and combining them is output as the power amount P of the battery 2.

  That is, the power amount PV based on the open-circuit voltage Vo of the battery 2 can be obtained as a substantially accurate value during normal use, but the value may vibrate when the load greatly fluctuates in a short time. There is. On the other hand, the power amount PC based on the current I of the battery 2 tends to accumulate errors, and is particularly resistant to load fluctuations such as inrush currents, while the error during high load continuation is large. Therefore, in this power amount calculation algorithm, a weight (weighting coefficient) that changes the power amount PV obtained based on the open circuit voltage Vo and the power amount PC obtained based on the current I as needed according to the usage state of the battery 2. By combining with weighting by w, both disadvantages are canceled and the mutual advantages are maximized.

  The weight w needs to be determined using a parameter that can accurately represent the current usage status of the battery 2, and includes the rate of change of current per unit time, the rate of change of power amount P, and the like. It is possible to use. The current change rate per unit time directly reflects the load fluctuation of the battery, but the mere current change rate is affected by a sudden change in current that occurs in a spike manner.

Therefore, in this embodiment, in order to prevent the influence of a change in current that instantaneously stops, a current change rate that has been processed by a simple average, a moving average, a weighted average, or the like of a predetermined sampling number is used. In particular, when considering the delay in current, the power amount PC using the moving average of the current I that can appropriately reflect the past history without excessively changing the charge / discharge state of the battery. And the weight w is determined. The weight w is changed between w = 0 and 1, and the final power amount P after synthesis is given by the following equation (1).
P = w * PC + (1-w) * PV (1)

  By determining the weight w based on the moving average value of the current I, when the moving average value of the current I is large, the weight of the power amount PC based on the current I is increased to increase the weight of the power amount PV based on the open circuit voltage Vo. , And the effect of load fluctuation can be accurately reflected by the current and vibration can be prevented. Conversely, when the moving average value of the current I is small, the weight of the power amount PC based on the current I is lowered, and the weight of the power amount PV based on the open circuit voltage Vo is increased, thereby avoiding the influence due to accumulation of current errors. In addition, an accurate power amount based on the open circuit voltage can be calculated.

  That is, the moving average of the current I becomes a low-pass filter for the high-frequency component of the current, and the moving average filtering can remove the spike component of the current generated by the load fluctuation during traveling without promoting the delay component. . Thereby, a vibration can be suppressed, grasping | ascertaining a battery state more correctly.

  Specifically, the power amount P shown in the equation (1) is an input possible power amount Pcharge indicated by the maximum power amount that can be input (charged) to the battery 2 and a maximum power amount that can be output (discharged) from the battery 2. The output possible power amount Pdischarge shown is a general term, and the following formulas (2) and (3) based on the formula (1) are used by the functions as the first to third calculation means in the calculation ECU 3, respectively. Are calculated individually.

That is, the input possible power amount Pcharge is calculated by the following equation (2), the power amount PVcharge as the first input possible power amount based on the open circuit voltage Vo, and the second input possible power amount based on the moving average of the current I. As a value obtained by weighted synthesis of the power amount PCcharge. Further, the output possible power amount Pdischarge is calculated by the following equation (3), the power amount PVdischarge as the first outputable power amount based on the open circuit voltage Vo, and the second outputable power amount based on the moving average of the current I. As a value obtained by weighting and combining the power amount PCdischarge.
Pcharge = w · PCcharge + (1-w) · PVcharge… (2)
Pdischarge = w · PCdischarge + (1-w) · PVdischarge (3)

  Specifically, the power amounts PVcharge, PVdischarge, PCcharge, and PCdischarge are the internal impedance Z of the battery 2, the open circuit voltage Vo, the upper limit voltage Vmax, the lower limit voltage Vmin, the moving average value of the current I, and the calculation cycle before one operation cycle. It is calculated using the input possible power amount Pcharge (t) and the output possible power amount Pdischarge (t) before one calculation period. Hereinafter, calculation of each power amount will be described.

  The internal impedance Z is obtained using an equivalent circuit model of the battery. For example, as shown in FIG. 3, resistance components R1 to R3, capacitance components C1, CPE1, and CPE2 (where CPE1 and CPE2 are double layer capacitance components) Each parameter is determined by curve fitting a well-known Cole-Cole plot in the AC impedance method using an equivalent circuit model in which these parameters are combined in series and in parallel, and the impedance Z is obtained from the determined parameter.

  The impedance Z obtained from each parameter varies greatly depending on the temperature of the battery, the electrochemical reaction rate, and the frequency component of the charge / discharge current. Therefore, as a parameter for determining the impedance Z, the moving average value of the current I is adopted as a replacement of the frequency component, the impedance measurement is performed on the condition of the moving average value of the current I and the temperature T, and the data is accumulated. Based on the temperature T and the moving average value of the current I, a table of impedance Z (an impedance table in FIG. 5 described later) is created, and the impedance Z is obtained using this table.

  As described above, the moving average value of the current I is also used as a parameter for determining the weight w, and the calculation of the weight w and the impedance Z is facilitated. Since the internal impedance increases and the current change rate decreases, as will be described later, the weight w and the impedance Z are directly determined using values obtained by temperature-correcting the moving average value of the current I.

  Of the power amounts PVcharge, PVdischarge, PCcharge, and PCdischarge calculated using the impedance Z, calculation of the input power amount PVcharge and the output power amount PVdischarge based on the open circuit voltage Vo will be described first.

When calculating the power amounts PVcharge and PVdischarge based on the open circuit voltage Vo, the open circuit voltage Vo is estimated by the following equation (4) using the impedance Z, the measured terminal voltage V and the current I, and is determined in advance. An upper limit voltage Vmax and a lower limit voltage Vmin, which are upper and lower battery voltages that guarantee battery characteristics, are obtained.
V = Vo-I · Z (4)

  The upper limit voltage Vmaxm and the lower limit voltage Vmin can be defined as a voltage when the remaining capacity SOC is the upper limit value (100%) and a voltage when the remaining capacity SOC is the lower limit value (0%), respectively, and change depending on the temperature. Therefore, in practice, it is obtained by referring to a table or the like using the temperature T as a parameter.

Then, using the open circuit voltage Vo, the upper limit voltage Vmax, and the lower limit voltage Vmin, the input possible power amount PVcharge and the output possible power amount PVdischarge are calculated by the following equations (5) and (6). The input possible power amount PVcharge is obtained as a power amount obtained by multiplying the difference between the upper limit voltage Vmax and the open circuit voltage Vo by the impedance Z and the upper limit voltage Vmax, and the output possible power amount PVdischarge is the open circuit voltage It is obtained as an electric energy obtained by multiplying the current value obtained by dividing the difference between Vo and the lower limit voltage Vmin by the impedance Z by the lower limit voltage Vmin.
PVcharge = [(Vmax−Vo) / Z] · Vmax (5)
PVdischarge = [(Vo−Vmin) / Z] · Vmin (6)

On the other hand, the power amounts PCcharge and PCdischarge based on the moving average of the current I use the combined power amount P (t−1) one cycle before the discrete time processing as a base value (delay calculation in the block diagram of FIG. 2). Child Z ^-1 ), errors do not accumulate or diverge, and even if the initial value is significantly different from the true value, the true value is reached after a predetermined time (for example, after several minutes). Can be converged to.

In other words, when the moving average value of the current I is I ′, as shown in the following equation (7), the combined input possible power amount Pcharge (t−1) before the calculation cycle and the moving average value I ′ have an impedance. Based on the input power amount I ′ ² Z multiplied by Z, a current input power amount PCcharge is obtained. Further, as shown in the following equation (8), the combined output possible power amount PCdischarge before one operation cycle and the output power amount I ′ ² Z obtained by multiplying the moving average value I ′ by the impedance Z The amount of output power PCdischarge is obtained.
PCcharge = Pcharge (t−1) −I ′ ² Z (7)
PCdischarge = Pdischarge (t-1) −I ′ ² Z (8)

  Then, as shown in the above equation (2), the input allowable power amount PVcharge calculated by the equation (5) and the input allowable power amount PCcharge calculated by the equation (7) are weighted using the weight w. Combining and calculating the input possible power amount Pcharge, and as shown in the above equation (3), the output possible power amount PVdischarge calculated by the equation (6) and the output possible power amount calculated by the equation (8) The PCdischarge is weighted using the weight w and combined to calculate the output possible power amount Pdischarge.

  Next, the calculation and combination processing of the power amounts PV and PC according to the above calculation algorithm will be described using the flowchart of the power amount calculation processing shown in FIG.

  Note that the flowchart of FIG. 4 shows the basic processing of the power amount calculation in the arithmetic ECU 3 of the power supply unit 1. In FIG. 4, for the convenience of explanation, the calculation of the power amount PV based on the open circuit voltage Vo is performed. Subsequently, the calculation of the power amount PC based on the moving average value I ′ of the current I is performed, but actually, the calculation of the power amounts PV and PC is executed in parallel.

  The power amount calculation process in FIG. 4 is executed at predetermined time intervals (for example, every 0.1 sec). First, in step S1, the terminal voltage V, current I, temperature T of the battery 2 and the previous calculation process are performed. The presence or absence of data input of the determined power amount P (t-1) is checked. The terminal voltage V is the average value of the plurality of battery packs, and the current I is the sum of the currents of the plurality of battery packs. For example, data is acquired every 0.1 sec. The temperature T is acquired every 10 seconds, for example.

  As a result, if there is no new data input in step S1, this process is left as it is. If there is new data input, the process proceeds from step S1 to step S2, and the moving average value I is obtained by moving average the current I. 'Is calculated. For example, when the current I is sampled every 0.1 sec and the calculation period of the power amount PC based on the current is every 0.5 sec, the moving average is a moving average of five data.

  Next, it progresses to step 3, the impedance Z of a battery equivalent circuit is calculated with reference to the impedance table shown in FIG. 5, and the open circuit voltage Vo of the battery 2 is estimated from the obtained impedance Z. This impedance table stores the impedance Z of the equivalent circuit using the corrected moving average value KI ′ obtained by correcting the temperature of the moving average value I ′ of the current I and the temperature T as parameters. When the rear moving average value KI ′ is the same, the impedance Z increases as the temperature T decreases. At the same temperature, the impedance Z tends to increase as the corrected moving average value KI ′ decreases. ing.

In the subsequent step S4, the upper limit voltage Vmax and the lower limit voltage Vmin of the battery 2 that change depending on the temperature T are calculated. The upper limit voltage Vmax and the lower limit voltage Vmin may be obtained by creating a dedicated table using the temperature T as a parameter and referring to this dedicated table. However, in this embodiment, the calculation ECU 3 of the power supply unit 1 is used. The calculation of the power amount and the calculation of the remaining capacity are performed in parallel, and the remaining capacity table having the open-circuit voltage Vo and the temperature T acquired based on the electrochemical relationship in the battery as parameters is held. Therefore, using this remaining capacity table,
That is, the relationship between the open circuit voltage Vo and the remaining capacity SOC can be expressed by the following equation (11) by applying a well-known Nernst equation describing the relationship between the electrode potential and the ion activity in an equilibrium state. it can.
Vo = E + [(Rg · T / Ne · F) × lnSOC / (100−SOC)] + Y (9)
However, E: Standard electrode potential (E = 3.745 in the lithium ion battery of this embodiment)
Rg: Gas constant (8.314 J / mol-K)
T: temperature (absolute temperature K)
Ne: Ion valence (Ne = 1 in the lithium ion battery of this embodiment)
F: Faraday constant (96485 C / mol)

In Equation (9), Y is a correction term, and represents the voltage-SOC characteristic at normal temperature as a function of SOC. If SOC = X, it can be expressed by a cubic function of SOC as shown in the following equation (10).
Y = −10 ⁻⁶ X ³ + 9 · 10 ⁻⁵ X ² + 0.013X−0.7311 (10)

  From the above equation (9), it can be seen that the remaining capacity SOC has a strong correlation not only with the open circuit voltage Vo but also with the temperature T. In this case, it is possible to directly calculate the remaining capacity SOC using the equation (9) using the open circuit voltage Vo and the temperature T as parameters. Consideration of conditions is necessary.

  Therefore, when grasping the actual state of the battery from the relationship of the above equation (9), a charge / discharge test or simulation in each temperature range is performed on the basis of the SOC-Vo characteristic at normal temperature, and the measured data is obtained. accumulate. Then, as shown in FIG. 6, a remaining capacity table in which the relationship between the open circuit voltage Vo and the remaining capacity SOC is tabulated is created from the accumulated measured data as shown in FIG.

  This remaining capacity table generally has a tendency that the lower the temperature T and the open circuit voltage Vo, the smaller the remaining capacity SOCv, and the higher the temperature T and the open circuit voltage Vo, the larger the remaining capacity SOCv. The remaining capacity SOC can be obtained by referring to the remaining capacity table using the temperature T and the open circuit voltage Vo as parameters. Furthermore, since the voltage that gives the upper limit (100%) and the voltage that gives the lower limit (0%) of the remaining capacity SOC are defined as the upper limit voltage Vmax and the lower limit voltage Vmin, respectively, the open circuit voltage Vo at a predetermined temperature T By referring to the upper and lower limits, the upper limit voltage Vmax and the lower limit voltage Vmin at the temperature T can be known.

  In the impedance table shown in FIG. 5 and the remaining capacity table shown in FIG. 6, the data in the range used under normal conditions are shown, and the data in other ranges is omitted.

  After obtaining the upper limit voltage Vmax and the lower limit voltage Vmin of the battery 2 that change depending on the temperature in step S4, the process proceeds to step S5, and correction of the upper limit voltage Vmax and the lower limit voltage Vmin is performed using the deterioration coefficient K considering the deterioration of the battery. I do.

  That is, the upper limit voltage Vmax and the lower limit voltage Vmin obtained by referring to the table in step S4 are based on the premise that the battery at the time of product shipment is not deteriorated. If the charge / discharge is repeated in the actual use state, the deterioration proceeds. The upper limit voltage Vmax that can maintain the guarantee characteristic of the battery is decreased, or the lower limit voltage Vmin is increased.

  For this reason, the upper limit voltage Vmax and the lower limit voltage Vmin are corrected by the deterioration coefficient D considering the deterioration of the battery. The deterioration coefficient D is given as a function of the internal resistance, for example, and is corrected so that the width between the upper limit voltage Vmax and the lower limit voltage Vmin becomes narrower as deterioration progresses.

  Thereafter, the process proceeds from step S5 to step S6, and the input possible power amount PVcharge and the output possible power amount PVdischarge based on the open circuit voltage Vo are calculated according to the above-described equations (5) and (6). According to the equations (7) and (8), the input possible power amount PCcharge and the output possible power amount PCdischarge based on the moving average value I ′ of the current I are calculated.

  In step S8, the weight w is calculated with reference to the weight table shown in FIG. The weight table is a one-dimensional table in which the corrected moving average value KI ′ obtained by correcting the temperature of the moving average value I ′ of the current I is used as a parameter, and roughly, as the corrected moving average value KI ′ decreases, In other words, the smaller the battery load variation, the smaller the value of the weight w tends to decrease the weight of the power amount PC due to the current.

  In the weight table of FIG. 7, the magnitude relationship of the weight w with respect to the temperature range is schematically shown, and detailed data on the weight w is omitted.

  In step S9, the power amount PC due to the current and the power amount PV due to the open circuit voltage Vo are weighted using the weight w according to the above-described equations (2) and (3), and the final combined input possible power amount Pcharge. And the combined output possible power amount Pdischarge are calculated, and one cycle of the calculation process is completed.

  FIG. 8 shows the input possible power amount (chargeable amount) calculated from the open circuit voltage of the battery, and a local rapid change occurs due to the influence of the spike component of the current. In particular, since the vibration due to the continuous spike component occurs after the elapsed time of 200 sec, the power amount is apparently substantially at the same level, but the power amount PVcharge based on the open circuit voltage and the moving average value of the current In the input possible power amount Pcharge obtained by weighting and combining the power amount PCcharge based on the weight w, as shown in FIG. 9, the spike component is removed and the vibration is suppressed, and the power amount increases with time. Is accurately captured.

  Further, FIG. 10 shows the output possible power amount (dischargeable amount) calculated from the open circuit voltage of the battery, and similarly, a local rapid change occurs due to the influence of the spike component of the current. Although the decrease in the power amount after the elapsed time of 100 sec is apparently reduced, the power amount PVdischarge based on the open circuit voltage and the power amount PCdischarge based on the moving average value of the current are weighted and synthesized using the weight w. In the possible power amount Pdischarge, as shown in FIG. 11, the spike component is removed and the vibration is suppressed, and the state in which the power amount decreases with time is accurately captured.

  As described above, in the present embodiment, the power amount based on the open circuit voltage and the power amount based on the charging / discharging current are used, and both are weighted and combined with the weight set according to the battery usage state. Obtaining the amount of power that accurately reflects the internal conditions of the battery (power storage device) without fluctuations in the calculated value due to load fluctuations under usage conditions or the deterioration of the calculated value due to variations in sampling data Can do.

System configuration diagram showing an example of application to a hybrid vehicle Block diagram showing power amount calculation algorithm Circuit diagram showing equivalent circuit model Flow chart of power amount calculation processing Illustration of impedance table Explanation of remaining capacity table Illustration of weight table Explanatory diagram showing the chargeable amount based on the open circuit voltage Explanatory drawing showing the calculation result of the combined input possible power amount Explanatory diagram showing the dischargeable amount based on the open circuit voltage Explanatory diagram showing the calculation result of the combined output possible power amount

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply unit 2 Battery 3 Calculation unit (1st, 2nd, 3rd calculation means)
I Charging / discharging current I 'Moving average value of charging / discharging current Vo Open voltage Z Internal impedance Vmax Upper limit voltage Vmin Lower limit voltage PVcharge Inputable power amount (first inputable power amount)
PVdischarge output power amount (first output power amount)
PCcharge input power amount (second input power amount)
PCdischarge output power amount (second output power amount)
Pcharge input power amount (input power amount after composition)
Pdischarge Outputable power amount (Outputable power amount after synthesis)
w weight
Agent Patent Attorney Susumu Ito

Claims (4)

First computing means for computing the first input possible power amount and the first output possible power amount based on the internal impedance and the open circuit voltage of the electricity storage device;
A second calculating means for calculating a second input possible power amount and a second output possible power amount based on the internal impedance and charge / discharge current of the power storage device;
The first inputtable power amount and the second inputtable power amount are weighted and synthesized using a weight set according to the usage status of the power storage device, and the inputable power amount of the power storage device is calculated. And third calculating means for calculating the output possible power amount of the power storage device by weight-combining the first output possible power amount and the second output possible power amount using the weight. An apparatus for calculating the amount of power of a power storage device. The first calculation means includes:
The first inputtable power amount is calculated using the internal impedance, open voltage and upper limit voltage of the power storage device, and the first outputable power amount is calculated using the internal impedance and open voltage of the power storage device. Calculate using the lower limit voltage,
The second calculation means includes:
While calculating said 2nd input possible power amount using the internal impedance of the said electrical storage device, the moving average value of charging / discharging current, and the input possible power amount before 1 calculation period, said 2nd output possible power amount The power amount calculation device for a power storage device according to claim 1, wherein the power storage device calculates the power using the internal impedance of the power storage device, the moving average value of the charge / discharge current, and the outputable power amount one calculation cycle before.   The power amount calculation device for an electricity storage device according to claim 1, wherein the weight is set based on a moving average value of a charge / discharge current of the electricity storage device.   The power amount of the electricity storage device according to any one of claims 1 to 3, wherein the internal impedance is calculated based on a moving average value of a charge / discharge current of the electricity storage device and a temperature of the electricity storage device. Arithmetic unit.

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