JP5393176B2 - Battery system and input / output power estimation method - Google Patents

Description

  The present invention belongs to the technical field of battery systems and input / output power estimation methods.

  Conventionally, the current-voltage characteristics of the battery are measured in advance, the current at the lower limit voltage is calculated from this line, the maximum current is calculated, and the power that the battery can output is calculated by multiplying the maximum current by the lower limit voltage. (For example, see Non-Patent Document 1).

  In some cases, the maximum current is estimated from the internal resistance value calculated by the sequential parameter estimation, and the power that can be output by the battery is calculated by multiplying the voltage (see, for example, Non-Patent Document 2).

Tominaga, Miyashita, “Study on Evaluation of Output Characteristics of Battery for EV”, Abstracts of 49th Battery Discussion Meeting, Electrochemical Society, November 2008, P.128 Yumoto, 3 others, “Method of estimating internal state quantity of battery using adaptive digital filter theory”, Preprint of Academic Lecture, Automobile Engineering Association, May 2003, Document No. 20035031, P.5 ~ P. Ten

  However, the conventional technique has a problem in that it is necessary to prepare a large number of input / output tables corresponding to the SOC because when the current-voltage characteristics measured in advance are used, it changes depending on the SOC.

  In addition, the conventional battery model has a problem that an error occurs in the estimation of the internal resistance at a large current and an error also occurs in the estimated value of the maximum current.

  The present invention has been made paying attention to the above problems, and its object is to provide a battery system and input / output power capable of accurately estimating the power that can be input / output of the battery without requiring a large amount of table data. It is to provide an estimation method.

To achieve the above object, according to the present invention, there is provided a battery system having a battery capable of charging / discharging a battery current, battery state measuring means for measuring the state of the battery, and an internal resistance component of the battery having a time constant. An equivalent circuit having parameters taking into account a large component and a component having a small time constant is set, and based on the state of the battery and the equivalent circuit, equivalent circuit parameter estimation means for sequentially estimating parameters of the equivalent circuit, An SOC calculating means for calculating an estimated SOC value based on the state and the parameter, and an inclination of the current-voltage characteristic serving as the internal resistance of the battery based on the sequentially estimated parameter, and an inclination of the current-voltage characteristic the internal resistance and maximum current calculating means for calculating the maximum current output possible of the battery on the basis of the back One of the power of the Li input and output possible power, the battery status, the inclination of the current-voltage characteristics, and on the basis of the maximum current and computation, the other of the input and output possible power of the battery And an input / output power calculating means for calculating the power based on the estimated SOC value .

  Therefore, in the present invention, it is possible to accurately estimate the power that can be input and output from the battery without requiring a large amount of table data.

1 is a block diagram illustrating a configuration of a battery device according to a first embodiment. It is a block diagram of the battery system with which the battery controller of the battery apparatus of Example 1 is provided. FIG. 3 is an explanatory diagram illustrating a block configuration of an equivalent circuit parameter estimation unit according to the first embodiment. FIG. 3 is a diagram illustrating an equivalent circuit configuration of the battery model according to the first embodiment. 4 is a flowchart illustrating a flow of input / output power calculation processing executed by the battery controller 2 of the battery device 1 according to the first embodiment. FIG. 3 is a graph showing the current-voltage characteristics of the battery in Example 1. It is a graph which shows the state calculated outside the current-threshold range in the case of calculating the inclination of the current-voltage characteristic in Example 1. FIG. It is a graph which shows the state in the electric current threshold range in the case of calculating the inclination of the current-voltage characteristic in Example 1. FIG. FIG. 3 is an explanatory graph illustrating a maximum current estimation state in the first embodiment. It is a time chart of the battery current and battery voltage at the time of creating a current-voltage characteristic. It is explanatory graph figure which shows the example of the produced current-voltage characteristic. It is explanatory graph which shows the relationship between the electric power which can be input and output, and SOC. It is explanatory graph figure which shows the state which calculates the maximum electric current in the current-voltage characteristic of a battery. It is explanatory drawing which shows the example of the equivalent circuit of a battery. It is a graph which shows the result of having estimated the maximum electric current of the battery of a discharge state.

  Hereinafter, an embodiment for realizing a battery system and an input / output power estimation method of the present invention will be described based on Example 1 corresponding to the invention according to claims 1 to 7.

First, the configuration will be described.
FIG. 1 is a block diagram illustrating the configuration of the battery device according to the first embodiment.
The battery device 1 according to the first embodiment includes a battery controller 2, a current sensor 3, a temperature sensor 4, a voltage sensor 5, a battery 6, and a load 7.
The battery controller 2 calculates the total capacity (battery capacity) of the battery 6 and input / output possible power.
The current sensor 3 measures the battery current output / input from the battery 6.
The temperature sensor 4 detects the battery temperature of the battery 6. The battery temperature measured by the temperature sensor 4 is a measure of the internal air of a part of the component or the component containing the unit battery cell outside the unit battery cell of the battery 6. It does not measure the internal temperature.
The voltage sensor 5 measures the battery voltage output from the battery 6.

The battery 6 is formed by connecting a plurality of unit battery cells 61 to form an assembled battery. Hereinafter, the battery 6 will be described as the battery 6. In Example 1, a lithium ion battery is taken as an example.
Note that SOC (State of charge, hereinafter abbreviated as SOC) is battery capacity (%).
The load 7 is a load driven by using the battery 6 as a power source. An example of the load 7 is a motor used for driving a vehicle.

FIG. 2 is a block diagram of a battery system provided in the battery controller 2 of the battery device according to the first embodiment. (The battery system described here executes the input / output power estimation method)
The battery controller 2 includes an equivalent circuit parameter estimation unit 21, an internal resistance and maximum current calculation unit 22, an SOC calculation unit 23, and an input / output power calculation unit 24.
The equivalent circuit parameter estimation unit 21 estimates an equivalent circuit parameter based on the battery current from the current sensor 3 and the battery voltage from the voltage sensor 5.
The internal resistance and maximum current calculation unit 22 calculates the internal resistance based on the current-voltage characteristics of the battery 6 and the maximum current based on the equivalent circuit parameters from the equivalent circuit parameter estimation unit 21.
The SOC calculation unit 23 calculates the SOC based on the equivalent circuit parameter from the equivalent circuit parameter estimation unit 21 and the battery current from the current sensor 3.
The input / output power calculator 24 is based on the battery temperature from the temperature sensor 4, the internal resistance and the internal resistance from the maximum current calculator 22, the maximum current, the battery current from the current sensor 3, and the SOC from the SOC calculator 23. The power that can be input / output from the battery 6 is calculated.

Next, the detailed configuration of the equivalent circuit parameter estimation unit 21 will be described.
FIG. 3 is an explanatory diagram illustrating a block configuration of an equivalent circuit parameter estimation unit according to the first embodiment.
The equivalent circuit parameter estimation unit 21 is an adaptive digital filter, and includes a battery calculation unit 211, a battery model 212, an adaptation mechanism 213, and a subtracter 214. It is a filter that self-corrects internal parameters.
The battery calculation unit 211 receives the measured battery current (i (k) inside the equivalent circuit parameter estimation unit 21) as an input to the control system and inputs the measured battery voltage (equivalent circuit parameter estimation). It is a calculation part set in the adaptive digital filter so as to output V (k) inside the unit 21. The battery calculation unit 211 is set to handle actual values.

The battery model 212 is an equivalent circuit that is a model of the battery 6, and adjusts the parameters of the equivalent circuit with the corrected output from the adaptive mechanism 213, and outputs a voltage model estimated value V ^ (k). Furthermore, the parameter of the equivalent circuit is output as the output of the equivalent circuit parameter estimation unit 21. For example, resistance values R0 to R2 and capacitor capacitances C1 and C2.
The adaptive mechanism 213 performs output for correcting the calculation content of the battery model 212 in accordance with the deviation calculated by the subtracter 214.
The subtracter 214 calculates the deviation between the output of the equivalent circuit parameter estimation unit 21, that is, the measured battery voltage V (k) and the voltage model estimated value V ^ (k).

Next, an equivalent circuit whose parameters are estimated by the battery model 212 will be described.
FIG. 4 is a diagram illustrating an equivalent circuit configuration of the battery model of the first embodiment.
As shown in FIG. 4, the equivalent circuit of the battery model 212 includes an open circuit voltage OCV, resistors R0, R1, R2, and capacitor capacities C1, C2.
Then, the open circuit voltage OCV, the resistor R0, the parallel connection portion of the resistor R1 and the capacitor capacitance C1, and the parallel connection portion of the resistor R2 and the capacitor capacitance C2 are connected in series.
Here, the resistor R0 is provided as a resistance of the electrolytic solution in the battery 6. The resistors R1 and C1 are provided as charge transfer resistors (electrode reaction resistors) in the battery 6.
Further, the resistor R2 and the capacitor C2 take into account diffusion resistance and the like.

The operation will be described.
[Input / output power calculation processing]
FIG. 5 is a flowchart showing a flow of input / output power calculation processing executed by the battery controller 2 of the battery device 1 of the first embodiment. Each step will be described below.

  In step S <b> 1, the battery controller 2 inputs battery current, battery temperature, and battery voltage from the current sensor 3, the temperature sensor 4, and the voltage sensor 5.

  In step S2, the equivalent circuit parameter estimation unit 21 estimates resistors R0 to R2 and capacitors C1 and C2, which are equivalent circuit parameters, using an adaptive digital filter. Then, the SOC calculation unit 23 integrates the sensor current to obtain a current integrated value, and calculates the SOC from the current integrated value and resistors R0 to R2 and capacitors C1 and C2 that are equivalent circuit parameters.

  In step S3, the internal resistance and maximum current calculation unit 22 determines whether or not the battery current is outside the preset threshold range. If it is outside the threshold range, the process proceeds to step S4, and if it is within the threshold range, the process proceeds to step S5.

  In step S4, the internal resistance and maximum current calculation unit 22 calculates the slope of the current-voltage characteristic, that is, the internal resistance R, from the resistances R0 to R2 and the capacitors C1 and C2 that are equivalent circuit parameters.

  In step S5, the internal resistance and maximum current calculation unit 22 sets the slope of the current-voltage characteristic, that is, the internal resistance R as the previous calculated value.

  In step S6, the internal resistance and maximum current calculation unit 22 calculates the maximum current from the slope of the current-voltage characteristic that is the internal resistance, the battery current detected by the sensor, and the battery voltage.

  In step S7, the input / output power calculation unit 24 determines whether or not the battery 6 is in a discharged state from the value of the battery current. If the battery 6 is in the discharged state, the process proceeds to step S8, and if it is in the charged state, the process proceeds to step S9.

  In step S8, the input / output power calculation unit 24 calculates the power that can be output, and the power that can be input refers to the table after the discharge has continued for a certain period of time. And The table data is obtained by measuring the relationship between SOC and power in advance and converting it into table data.

  In step S9, the input / output power calculation unit 24 calculates the power that can be input, and the power that can be output refers to the table after the charging has continued for a certain period of time. To do.

  In step S10, it is determined whether or not the vehicle is stopped from information or signals obtained from the vehicle by the battery controller 2. If the vehicle is stopped, the process is terminated. If the vehicle is not stopped, the process returns to step S1.

[Battery input / output power estimation accuracy improvement effect]
FIG. 6 is a graph showing the current-voltage characteristics of the battery in Example 1.
The current-voltage characteristics in the SOC with the battery 6 are as shown in FIG. In addition to the SOC, the battery controller 2 transmits power that can be input (charged) and power that can be output (discharged) to the upper controller. The host controller controls the current for charging / discharging the battery 6 according to the electric power.

If the maximum current shown in FIG. 6 can be calculated accurately, the power that can be output is calculated from the product of the maximum current (discharge) and the lower limit voltage (for example, 2.5 V), and the maximum current (charge) and the upper limit voltage (for example, 4.2) is calculated. It is possible to calculate the input power from the product of V).
The lower limit voltage is set as a limit value for discharging the battery, and the upper limit voltage is set as a limit value for charging the battery.
The upper limit voltage and the lower limit voltage are values determined by the system. However, since the maximum current changes according to the temperature and deterioration state of the battery 6, it is difficult to calculate the power that can be input and output.
In the first embodiment, the power that can be input / output with high accuracy is calculated corresponding to the maximum current due to the state change.

(Equivalent circuit parameter estimation)
The equivalent circuit parameter estimation unit 21 includes a diffusion resistor having a large time constant in FIG. 4 and an equivalent circuit having an electrode reaction resistance having a small time constant in comparison with the battery model 212 in FIG. Calculation is performed with a model that is closer to the actual state, including a transient state. For this reason, the estimation accuracy is improved by setting the resistors R1 and R2 that are greatly affected by the SOC, the battery temperature, the battery current, and the deterioration state.
In the equivalent circuit parameter estimation unit 21, the deviation between the battery voltage V (k) measured as the output of the battery calculation unit 211 set as an actual value and the voltage model estimation value V ^ (k) is reduced. As described above, the adaptive mechanism 213 changes the parameters of the battery model 212. Since this is sequentially changed during the calculation, it is a sequential state estimation, and the parameters of the battery model 212 are very well captured actual battery states. (V ^ represents the estimated value of V. Actually, ^ is on V.)

  The parameters of the battery model 212 are output, and the subsequent calculation is performed to further improve the estimation accuracy of the input / output power of the battery 6. In addition, the process of the equivalent circuit parameter estimation part 21 is performed as a process of step S2.

(Calculation of slope of current-voltage characteristics)
FIG. 7 is a graph showing a state calculated outside the current threshold range when calculating the slope of the current-voltage characteristic in the first embodiment. FIG. 8 is a graph showing a state within the current threshold range when calculating the slope of the current-voltage characteristic in the first embodiment.
Once the parameters of the equivalent circuit are estimated, the slope of the current-voltage characteristic is calculated next. This process is performed in steps S3 to S5. The slope of this current-voltage characteristic is the internal resistance R.
In FIG. 7, the current threshold range is indicated by reference numeral 102. A current-voltage characteristic of the battery 6 is denoted by reference numeral 101. Then, when the current value is in a range (calculation range) indicated by reference numeral 103 in FIG. 7 and is outside the current threshold range, the slope of the current-voltage characteristic is sequentially calculated.
In that case, the slope of the current-voltage characteristic is sequentially calculated from the equivalent circuit parameters estimated by the equivalent circuit parameter estimation unit 21 using the following equation.

電流閾値範囲１０２の範囲内の場合には、前回値とする。これは、電流が０(A)に近い電流閾値範囲１０２の範囲内において、推定される電流電圧特性の傾きの値が、実際の閾値範囲における電流電圧特性の傾きより大きな値となり、最大電流推定値が実際の値より小さな値になるのを防ぐ処理である。
なお、前回値を使っても問題ないのは、傾きの大きな電流から電流閾値範囲１０２へ電流が変化することはなく、実際には、図８に矢印１０４で示すように、電流と電圧の測定周期により範囲外で電流閾値範囲１０２の範囲内と傾きが同じ電流から、電流閾値範囲１０２の範囲内に電流が変化するからである。
また、図８に矢印１０５で示すように電流の符号が変化しても、電流閾値範囲１０２の範囲内で傾きがほぼ同じであるので、問題はない。

If it is within the current threshold range 102, the previous value is used. This is because the value of the slope of the estimated current-voltage characteristic is larger than the slope of the current-voltage characteristic in the actual threshold range within the current threshold range 102 where the current is close to 0 (A), and the maximum current estimation This process prevents the value from becoming smaller than the actual value.
It should be noted that there is no problem even if the previous value is used, since the current does not change from the current having a large slope to the current threshold range 102, and actually, as shown by the arrow 104 in FIG. This is because the current changes within the current threshold range 102 from the current having the same slope as the current threshold range 102 outside the range depending on the period.
Even if the sign of the current changes as indicated by an arrow 105 in FIG. 8, there is no problem because the slope is substantially the same within the current threshold range 102.

(Estimated maximum current)
FIG. 9 is an explanatory graph showing the maximum current estimation state in the first embodiment.
Once the slope of the current-voltage characteristic has been calculated, the maximum current is next estimated. This process is performed in the process of step S6.
In FIG. 9, the upper limit voltage and the lower limit voltage are preset from the system. For example, in FIG. 9, assuming that the battery current, battery voltage, and estimated internal resistance at point a 106 and b point 107 are linear slopes (Ra, Rb), the maximum current at each of points a and b is given by Can be calculated.

  (Equation 2)

  Lower limit voltage −v = R × (maximum current−i)

  From Equation 2,

  (Equation 3)

  Maximum current = (lower limit current−v) / R + i

  Here, if point a, i = ia, v = va, R = Ra, and point b, i = ib, v = vb, R = Rb. In FIG. 9, the slope Ra (internal resistance) is denoted by reference numeral 108 and the slope Rb (internal resistance) is denoted by reference numeral 109.

In this manner, the power that can be output at point a 106 and point b 107 is sequentially estimated from the product of the calculated maximum current and lower limit voltage.
Particularly, at the point b of the large current 107, since the changes of the resistance R2 and the capacitor C2 representing diffusion are sequentially estimated in the equivalent circuit of the battery 6 in FIG. 4, the slope Rb at the point b 107 is accurately calculated, and the output power The estimation accuracy of is improved.
Since the current at point a 106 is smaller than that at point b 107, the maximum current increases, and the output power can be larger than that at point b 107. This indicates that the discharge capacity is maintained in the small current discharge. Further, the decrease in the power that can be output at the point b 107 indicates that the discharge capacity decreases due to the large current discharge.
Similarly, in the case of charging, if the maximum current is calculated, the power that can be input is sequentially estimated from the product of the upper limit voltages.

In order to clarify the operation of the first embodiment, further explanation will be added.
FIG. 10 is a time chart of the battery current and the battery voltage when creating the current-voltage characteristics. FIG. 11 is an explanatory graph showing an example of the created current-voltage characteristics.
In order to estimate the power that can be input and output, it can be estimated as follows.
In a certain SOC, discharging is performed with a current i1 (A), and a terminal voltage v1 (V) after t (s) is measured. Similarly, terminal voltages v2, v3 (V) at currents i2, i3 (A) are measured (see FIG. 10). Create a current-voltage characteristic from the measured current and voltage, extend the straight line and set the current at 2.5 (V) as the maximum current, and the product of the maximum current and voltage 2.5 (V) is the output at this SOC. (Discharge) is possible power (see FIG. 11).
In the case of charging, the maximum current is calculated in the same manner, and the power that can be input (charged) in a certain SOC is calculated from the product of the maximum current and the voltage of 4.2 (V).

FIG. 12 is an explanatory graph showing the relationship between input / output power and SOC. FIG. 12A shows the relationship between the power that can be input and the SOC of the power that can be output, created by changing the SOC.
In the content described above with reference to FIGS. 10 and 11, as shown in FIG. 11, an error occurs between the estimated value of the maximum current value and the actual maximum current. For this reason, an error occurs in the relationship between the power that can be input and output and the SOC shown in FIG.
Furthermore, it is necessary to correct the table data according to the battery temperature or deterioration, or to prepare a large number of table data in advance.

FIG. 12B shows a comparison between the input power (reference numeral 110) calculated with the contents described above with reference to FIGS. 10 and 11 and the input power (reference numeral 111) calculated in the first embodiment.
Since there is an error in the power that can be input calculated with the content described above with reference to FIGS. 10 and 11, the table data is set at a value lower than the actual power. On the other hand, in the first embodiment, since the power that can be input is accurately calculated, the battery usage time is extended by inputting (charging) the power to the battery by the amount indicated by A in FIG. It will be. Thereby, the battery can be miniaturized. The same applies to the output, and the capacity of the battery can be used without waste, so that the size can be reduced.

Further, it is conceivable that the parameters of the equivalent circuit model are determined by the time constant of the low-pass filter.
FIG. 13 is an explanatory graph showing a state in which the maximum current is calculated in the current-voltage characteristics of the battery.
Since the current-voltage characteristic is curved as shown in FIG. 13, an error occurs in the model with a large current unless an appropriate low-pass filter is set. Since the equivalent circuit model itself is not a model including two different time constants, the slope at the current whose slope changes due to the diffusion, that is, the internal resistance cannot be accurately calculated. In this case, the estimated value of the maximum current is calculated by the following equation. However, as shown in FIG. 13, the estimated value of the maximum current is small and an error occurs in the calculated input power. .

(Equation 4)
Current-voltage characteristic slope R = (open-circuit voltage−lower limit voltage) / maximum current

(Equation 5)
Maximum current estimate = (open circuit voltage-lower limit voltage) / current voltage characteristic slope R

FIG. 14 is an explanatory diagram showing an example of an equivalent circuit of a battery.
As an equivalent circuit of the battery 6, the one shown in FIG. 14 can be considered. However, in the equivalent circuit shown in FIG. 14, since the electrode reaction resistance and the diffusion resistance are not separated and the time constant is ambiguous, the straight line of the slope R of the current-voltage characteristic and a Even when the maximum current is obtained from the straight line at point 106 and the current value and voltage value at point a, the maximum current is larger than the actual maximum current of battery 6.
On the other hand, in the first embodiment, the configuration shown in FIG. 4 is shown as an equivalent circuit, and the electrode reaction resistance and the diffusion resistance are separated, and it is advantageous to perform estimation closer to the actual battery state.

Further explanation will be added.
FIG. 15 is a graph showing a result of estimating the maximum current of a battery in a discharged state. In FIG. 15, the maximum current is indicated by symbol P, the actual battery 6 measured is indicated by symbol 112, and the contents described above with reference to FIGS. 10 and 11 are used with the equivalent circuit of FIG. What is estimated is indicated by reference numeral 114, and what is estimated in the first embodiment is indicated by reference numeral 113.
In the first embodiment, as shown in FIG. 15, it can be seen that the estimation accuracy of the maximum current is improved and the estimation closer to the actual battery 6 can be performed.

Explain the effect. The battery system and the input / output power estimation method according to the first embodiment have the effects listed below.
A battery controller 2 having a battery 6 that performs charging and discharging, a current sensor 3 that measures the state of the battery 6, a temperature sensor 4, a voltage sensor 5, and an internal resistance component of the battery 6 with a component having a large time constant and a time An equivalent circuit having parameters R1, R2, C1, and C2 in consideration of components having small constants is set, and an equivalent circuit parameter estimation unit 21 that sequentially estimates parameters of the equivalent circuit based on the state of the battery and the equivalent circuit, and the battery 6 SOC calculation unit 23 for calculating the estimated SOC value based on the state of the current and the parameter, and the slope R of the current-voltage characteristic serving as the internal resistance of the battery 6 based on the sequentially estimated parameter, and the internal resistance and maximum current calculator 22 for calculating the maximum current output possible of the battery based on the inclination R, of the available input and output power of the battery One of power, battery state, the gradient of the current-voltage characteristics, and to computation on the basis of the maximum current, the other power of the available input and output power of the battery, the input to calculation based on the SOC estimation value Since the output power calculation unit 24 is provided, the internal resistance separated from the parameters of the equivalent model by the magnitude of the time constant is sequentially estimated, and the internal resistance is sequentially estimated accurately as the slope of the current-voltage characteristics. Without requiring data, it is possible to accurately estimate the power that can be input and output from the battery.

  (2) In the above (1), the parameters of the battery model 212 of the equivalent circuit parameter estimation unit 21 include the diffusion reaction of the battery 6 as components R2, C2 having a large time constant, and the electrode reaction of the battery is a component having a small time constant. Since R1 and C1 are provided, the parameters estimated sequentially are divided into diffusion reactions and electrode reactions, and the parameter estimation accuracy can be made closer to the actual, thereby improving the input / output power estimation accuracy.

  (3) In the above (1) or (2), the battery state measuring means includes the current sensor 3 for detecting the battery current of the battery 6 and the voltage sensor 5 for detecting the battery voltage of the battery 6, and the internal resistance and the maximum The current calculation unit 22 surrounds the maximum current outside the current threshold range in the current threshold range 102 set as a current-voltage region in which the current value is close to 0 in the current-voltage characteristic of the battery and the current-voltage characteristic of the battery 6. Since the range 103 set as the current-voltage region is provided, and the battery current is in the range 103, the slope R of the current-voltage characteristic of the battery 6 is sequentially calculated. It is possible to prevent the maximum current estimated value from becoming smaller than the actual value, and to improve the estimation accuracy of the slope R of the current-voltage characteristics. It is possible to improve the estimation accuracy of the force.

  (4) In the above (3), when the battery current is in the current threshold range 103, the internal resistance and maximum current calculation unit 22 uses the previously calculated slope of the current-voltage characteristics as the calculation result, so that the maximum current estimated value Can be prevented from becoming smaller than the actual value, and the processing load can be reduced by using the previous value within a range where there is no problem.

  (5) In the above (1) to (4), a lower limit voltage indicating a battery discharge limit and an upper limit voltage indicating a battery charge limit are set in advance, and the input / output power calculation unit 24 has a current-voltage characteristic. In order to calculate the input possible power or the output possible power from the slope R and the lower limit voltage or the upper limit voltage, the point where the upper and lower limit voltage and the slope R intersect is calculated as the input possible power or the output possible power and set from the system used. In consideration of the upper and lower limit voltages, the input / output power can be estimated, and the estimation calculation suitable for the actually used system can be performed.

  (6) In the above (5), the input / output power calculation unit 24 is provided with the relationship between the SOC and the input / output power as data shown in FIG. The input possible power or the output possible power is calculated from the slope of the current-voltage characteristic and the lower limit voltage or the upper limit voltage, and the input possible power or output possible power of the other battery state is calculated from the data on the relationship between the SOC and the input / output power. Therefore, it is possible to accurately estimate both the input power and the output power by reducing the number of table data.

  (7) The state of the battery 6 to be charged / discharged is measured (Step S1), and the internal resistance component of the battery 6 has parameters R1, C1, R2, and C2 that take into account a component having a large time constant and a component having a small time constant. An equivalent circuit is set, parameters of the equivalent circuit are sequentially estimated based on the battery state and the equivalent circuit (step S2), an SOC estimated value is calculated based on the battery state and the parameter (step S2), and the successive estimation is performed. Based on the parameters to be calculated, the slope of the current-voltage characteristic that becomes the internal resistance of the battery is calculated (step S4), the maximum current that can be input / output from the battery is calculated based on the slope of the current-voltage characteristic (step S6), Since the battery input / output power is calculated based on the battery state and SOC, the slope of the current-voltage characteristic, and the maximum current (step S8), the parameters of the equivalent model are calculated. The internal resistance separated from the time constant by the magnitude of the time constant is sequentially estimated, and the internal resistance is estimated sequentially with high accuracy as the slope of the current-voltage characteristics. Can be estimated with high accuracy.

  As described above, the battery system and the input / output power estimation method of the present invention have been described based on the first embodiment. However, the specific configuration is not limited to these embodiments, and each claim of the claims Design changes and additions are permitted without departing from the spirit of the invention.

  For example, in the first embodiment, the equivalent circuit parameter estimation unit 21 includes the adaptive digital filter, but may include a Kalman filter.

DESCRIPTION OF SYMBOLS 1 Battery apparatus 2 Battery controller 21 Equivalent circuit parameter estimation part 211 Battery calculation part 212 Battery model 213 Adaptation mechanism 214 Subtractor 22 Maximum current calculation part 23 SOC calculation part 24 Input / output electric power calculation part 3 Current sensor 4 Temperature sensor 5 Voltage sensor 6 Battery 61 Unit battery cell 7 Load

Claims (7)

A battery system having a battery capable of charging and discharging battery current ,
Battery state measuring means for measuring the state of the battery;
An equivalent circuit having parameters taking into account a component having a large time constant and a component having a small time constant is set as the internal resistance component of the battery, and the parameters of the equivalent circuit are sequentially estimated based on the state of the battery and the equivalent circuit. Equivalent circuit parameter estimation means;
SOC calculating means for calculating an estimated SOC value based on the state of the battery and the parameter;
The internal resistance and the maximum current are calculated based on the parameters that are sequentially estimated to calculate the slope of the current-voltage characteristic that becomes the internal resistance of the battery, and the maximum current that can be input / output from the battery is calculated based on the slope of the current-voltage characteristic. A calculation means;
One of the power of the available input and output power of the battery, the battery condition, the slope of the current-voltage characteristics, and to computation on the basis of the maximum current, of the available input and output power of the battery Input / output power calculating means for calculating the other power based on the estimated SOC value ;
With
A battery system characterized by that. The battery system according to claim 1,
The parameter of the equivalent circuit includes the diffusion reaction of the battery as a component with a large time constant, and the electrode reaction of the battery as a component with a small time constant.
A battery system characterized by that. The battery system according to claim 1 or 2,
Battery state measuring means
Current detecting means for detecting the battery current of the battery,
Voltage detecting means for detecting a battery voltage of the battery;
With
The internal resistance and maximum current calculation means are:
In the current-voltage characteristics of the battery, a current threshold range set as a current-voltage region where the current value is in the vicinity of 0,
In the current-voltage characteristics of the battery, a calculation range set as a current-voltage region surrounding the maximum current outside the current threshold range;
When the battery current is in the calculation range, the slope of the current-voltage characteristics of the battery is sequentially calculated.
A battery system characterized by that. The battery system according to claim 3, wherein
The internal resistance and maximum current calculation means are:
When the battery current is in the current threshold range, the slope of the current-voltage characteristic calculated last time is used as the calculation result.
A battery system characterized by that. In the battery system according to any one of claims 1 to 4,
A lower limit voltage indicating a limit of discharge of the battery, and an upper limit voltage indicating a limit of charge of the battery are set in advance,
The input / output power calculation means includes:
Calculate input power or output power from the slope of the current-voltage characteristics and the lower limit voltage or the upper limit voltage,
A battery system characterized by that. The battery system according to claim 5, wherein
The input / output power calculation means includes:
The relationship between SOC and input / output power is prepared as data in advance.
The input possible power or output possible power of the battery state of either input / output determined from the battery current is calculated from the slope of the current-voltage characteristics and the lower limit voltage or the upper limit voltage,
The input possible power or the output possible power of the other battery state is calculated from the data on the relationship between the SOC and the input / output power.
A battery system characterized by that. Measure the battery state that can charge and discharge the battery current ,
Set an equivalent circuit having parameters that take into account electrode reaction and diffusion reaction in the internal resistance component of the battery,
Based on the state of the battery and the equivalent circuit, sequentially estimate the parameters of the equivalent circuit,
An SOC estimated value is calculated based on the battery state and the parameter, and a slope of a current-voltage characteristic that becomes an internal resistance of the battery is calculated based on the parameter estimated sequentially,
Calculate the maximum current that can be input and output from the battery based on the slope of the current-voltage characteristics.
One of the power of the available input and output power of the battery, the battery condition, the slope of the current-voltage characteristics, and to computation on the basis of the maximum current, of the available input and output power of the battery An input / output power estimation method , wherein the other power is calculated based on the estimated SOC value .

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