JP2003243017A - Electric equivalent circuit model forming method for secondary battery and simulation method and program using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric equivalent circuit model forming method for a secondary battery used for investigating the specifications of the secondary battery for purposes of using an overload region, and to provide a simulation method and a program using this method. <P>SOLUTION: A current source I simulates input output current; a current source i<SB>0</SB>simulates self discharge characteristics; C<SB>0</SB>simulates battery capacity; R<SB>1</SB>simulates membrane resistance, electrolyte resistance, and contact resistance; R<SB>2</SB>//C<SB>2</SB>simulates resistance caused by movement and diffusion of charges and ions; and R<SB>3</SB>//C<SB>3</SB>simulates resistance depending on active material supply on the inside of a cell, to express the electric equivalent model for the secondary battery, a current value is calculated by using an optionally set output command and voltage value on the electric equivalent circuit model, and voltage on the equivalent circuit model used next time is calculated based on the calculated current value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of creating an electrical equivalent circuit model of a secondary battery, a simulation method and a program using the same, and more particularly, to an internal state of a secondary battery such as a redox flow battery or a sodium-sulfur battery. By modeling with an electrical equivalent circuit, it is possible to quantitatively grasp the characteristics such as the state of charge of the battery from the history of the input and output of the battery, a method for creating an electrical equivalent circuit model of a secondary battery,
The present invention relates to a simulation method and program using this.

[0002]

2. Description of the Related Art Secondary batteries such as redox flow batteries and sodium-sulfur batteries are expected to play a role of load leveling by charging with electric power at night and discharging during daytime. Further, the redox flow battery has an extremely high response speed to an output command and little deterioration due to repeated charging / discharging, and thus is expected to be applied to supply / demand control. Furthermore, since the redox flow battery has high tolerance to short-time overload, it is expected to be applied to load frequency control (LFC) that absorbs short-cycle frequency fluctuations by using the overload region. Has been done.

When operating in the overload region, the internal state of the battery, such as the charging state, changes drastically in a short time. Therefore, in order to continue the stable operation of the battery, the battery rating, pump flow rate, and It is necessary to examine each parameter such as load usage area in advance.

[0004]

However, there has been no electrical equivalent circuit model inside the battery until now,
Since the preliminary examination by simulation was impossible, it was not possible to examine the specifications of the redox flow battery in detail for the purpose of using the overload region.
In addition, it was not possible to estimate the ability to use the overload region at each time during driving.

Therefore, a main object of the present invention is to prepare an electrical equivalent circuit model of a secondary battery used for studying the specifications of a redox flow battery for the purpose of using an overload region. It is to provide the used simulation method and program.

[0006]

SUMMARY OF THE INVENTION The present invention is a method for creating an electrical equivalent circuit model in which the internal state of a secondary battery is modeled by an equivalent circuit. It is characterized in that it is represented by a first-order lag block consisting of a capacitor and a resistor of No. 1, a charge depth at the time of input / output is represented by a second capacitor, and a self-discharge characteristic is represented by a current source.

The constant output duration characteristic is characterized in that it includes a region having a relatively long duration, a region having a relatively short duration, and an intermediate region.

The first-order lag block is characterized by including a resistance component due to charge / ion migration / diffusion of the secondary battery and a resistance component determined by the supply of the active material inside the cell.

Further, the constant of the first-order lag block is characterized by being simulated by a non-linear resistance depending on the battery voltage.

Another invention is a simulation method using an electrical equivalent circuit model of a secondary battery, in which a current value is calculated by using an arbitrarily set output command value and a voltage value on the electrical equivalent circuit model. The voltage on the equivalent circuit model used in the next calculation is calculated from this current value.

Further, a part or all of the voltage values are measured values. Furthermore, another invention is a simulation program using an electrical equivalent circuit model of a secondary battery, wherein a current value is calculated using an output command value set arbitrarily and a voltage value on the electrical equivalent circuit model. The voltage on the equivalent circuit model used in the next calculation is calculated from this current value.

[0012]

1 is a block diagram showing a system configuration of a redox flow battery among secondary batteries to which the present invention is applied. In FIG. 1, the positive electrode liquid stored in the positive electrode electrolyte tank 1 is sent to the positive electrode chamber 31 in the battery cell 3 by the circulation pump 2. The positive electrode liquid undergoes an electrochemical reaction with electrons that flow in and out through the positive electrode 33 provided in the positive electrode chamber 31, thereby changing the valence of metal ions contained in the positive electrode liquid.

The negative electrode liquid stored in the negative electrode electrolytic solution tank 4 is also sent to the negative electrode chamber 32 in the battery cell 3 by the circulation pump 5 in the same manner as the positive electrode liquid. In synchronization with the reaction of the positive electrode liquid, the negative electrode liquid electrochemically reacts with the electrons that flow in and out through the negative electrode 34 provided in the negative electrode chamber 32.

When a vanadium-based electrolyte is used, V ⁴⁺ → V ⁵⁺ + e ⁻ (oxidation reaction) at the positive electrode 33 and V ³⁺ + e ⁻ → V ²⁺ (reduction reaction) at the negative electrode 34 during charging.
Electrochemical reaction occurs. On the other hand, during discharge, the reaction in the opposite direction occurs at each electrode, that is, V ^{5+ at the} positive electrode 33
+ E ⁻ → V ⁴⁺ (reduction reaction), V ²⁺ → V at the negative electrode 34
³⁺ + e ⁻ (oxidation reaction) proceeds. Synchronization between the reaction at the positive electrode and the reaction at the negative electrode is ensured by balancing the charges by the electrons moving in the external circuit and the protons in the electrolytic solution passing through the diaphragm 35. The effect of charging and discharging is retained as the ratio of metal ions of different valences that change mutually in the above charge / discharge reaction to the total metal ions when the total number of metal ions in the electrolytic solution is kept constant. .

The redox flow battery 10 is an inverter 6
Is connected to the system side via. The detection system 7 detects the system frequency on the system side or receives the output command value, and the control system 8
Controls the inverter 6 according to the frequency deviation detected by the detection system 7 or the output command value to output active power. When the control system 8 controls the inverter 6 according to the output command value, the battery current value that matches the output command value and the battery voltage value is calculated so that the current value of the inverter 6 becomes that value. Controlled.

FIG. 2 is a diagram showing the response characteristics of the redox flow battery system at the time of overload output.

The load output when the inverter 6 is operated by stepwise inputting the active power output command value P to the control system 8 shown in FIG. 1 is shown in FIG. 2. From this FIG. 2, the maximum load output of the redox flow battery is shown. Charge Depth (SOC: State Of Charg
It turns out that it depends on e).

FIG. 3 is a diagram showing a DC output vs. duration characteristic of the redox flow battery system. This characteristic is that the active power output command value P is stepwise input to the control system 8 of the inverter 6 to operate the inverter 6, and the output value and the DC voltage when the redox flow battery 10 is overcharged or undercharged have the specified values. It is a measurement of the time until it cannot be maintained.

The relationship between duration than 3 and the output is divided into three regions, but based on the Peukert equation is empirical equation of the load current over time characteristic of the battery I ⁿ t = C (I: load current,
When the formulation of FIG. 3 (straight line approximation on a logarithmic log graph) is performed according to t: time, C: constant), a region of more than 300 seconds (n = 3: function 1) and about 3 to 300 seconds. Area (n = 1
0: Function 3) and area up to 3 seconds (n = 30: Function 3)
Can be divided into

When considering the physical property model of the redox flow battery from the principle of chemical reaction, the "battery capacity" is the dominant factor in the time region of over 300 seconds, and "the ionic substance inside the cell" in the time region of up to about 300 seconds. It is considered that "movement" is the controlling factor, and "redox reaction resistance, film resistance, contact resistance" is the controlling factor in the short-time region up to 3 seconds.

Therefore, the constant output duration characteristics of the redox flow battery for the three regions can be expressed by an equivalent circuit shown in FIG. 4 in which first-order delay blocks by CR are connected in two stages.

In FIG. 4, the current source I (t) is an input / output current, the current source i ₀ is a self-discharge characteristic, and C ₀ is a battery capacity. R ₁ is membrane resistance, liquid resistance, contact resistance, R ₂ // C ₂
Is the resistance due to charge / ion migration / diffusion, R ₃ // C ₃
Represents a resistance component determined by the supply of the active material inside the cell.

FIG. 5 is a diagram showing the non-linear resistance characteristic of the redox flow battery. From FIG. 5, it can be seen that the change in the terminal voltage becomes steeper in the low SOC region such as 10% than in the case where the SOC is 50%, and the characteristics change. This is because the constant value is S
This is a function of OC.

FIG. 6 is a diagram showing the efficiency of a single battery with respect to the changing cycle of the inverter command value P. This FIG. 6 shows an inverter 6 in order to analyze the change in efficiency depending on the charging cycle.
The effective power output command value P given to the control system 8 is periodically changed to measure the efficiency of the battery unit.

Further, in FIG. 6, the maximum value of the command value P of the inverter 6 is measured separately for two cases of the rated output and twice the rated output. From FIG. 6, it is understood that in the case of the rated output, the efficiency slightly decreases as the charging / discharging cycle becomes longer. Further, at twice the rated output, the efficiency is almost the same as the rated output when the charging / discharging cycle is short, but when the charging / discharging cycle is long, the efficiency is much lower than at the rated value. In either case, if the charge / discharge cycle becomes longer,
The charging / discharging efficiency of the redox flow battery 10 is reduced, and it is considered that this is because the internal resistance of the redox flow battery 10 increases as the output duration time increases.

As described above, it is considered that the secondary battery utilizes the overload region and is widely utilized in addition to load leveling, such as supply and demand control and measures against instantaneous voltage drop. Among them, the redox flow battery 10 is used for SOC. The output limit value fluctuates accordingly, and the constant output duration fluctuates. Further, the charge / discharge loss rate also changes depending on the output fluctuation cycle. Other secondary batteries also have similar features to varying degrees.

From the above, when applied to various actual applications, the operation is simulated, the operating condition corresponding to the control is reproduced to calculate the operating cost, the output fluctuable range is obtained, and the operating condition is calculated. Efficiency needs to be calculated. In order to carry out such studies, it is necessary to calculate the operating cost using a model that can dynamically express the effects of control and the above-mentioned characteristics. Therefore, each constant of the redox flow battery model shown in FIG. 4 is determined and the model is constructed.

FIG. 7 is a diagram showing the relationship between the monitor cell voltage V _cell and the SOC for measuring the self-discharge amount. From FIG. 7, dV _cell / d in the region where SOC is larger than 25%
It can be seen that the relationship of SOC = 0.3 holds.
First, consider a region with a large SOC.

Next, the redox flow battery 10 is charged with SOC.
V _cell was measured by waiting at 50% and pump flow rate of 100% (output P = 0).

FIG. 8 is a diagram showing the measurement results of the self-discharge amount measurement test. It can be seen from FIG. 8 that the voltage drops at a rate of ΔV _cell = 50 μV / min. Here, the electrolytic solution and the cell specifications of the redox flow battery 10 are as follows: electrolytic solution amount: 30 L / tank, electrolytic solution concentration: 2 mol / L,
Cell configuration: 30 cells (series) + monitor cell, monitor cell: Vcell = 0.3V (active material 100%), the active material amount Q on the positive electrode side and the negative electrode side is expressed by the formula (1).

Q = 2 mol / L × 30 L × 96,500 c / mol / 30 cells (1) = 193,000 C / cell Therefore, the self-discharge amount i ₀ is obtained by the equation (2).

I ₀ = dQ / dt = dV _cell / dt · dSOC / dV _cell · dQ / dSOC = 0.536 A / cell (2) Next, from the response characteristics of the terminal voltage of the redox flow battery to the step current input, Various constants of the equivalent circuit model in the high SOC region are determined. Determine the constant from the terminal voltage characteristics during charging and discharging at the rated current (SO
C: 50%, flow rate: 100%)
The standard constant value is the average of constant values calculated during charging and discharging.

FIG. 9 is a diagram showing the actual measurement results of the terminal voltage response characteristics of the redox flow battery during charging with respect to the step current.

The terminal voltage response V (t) when the step current I is applied to the redox flow battery equivalent circuit model is
If the initial condition is V ₂ (0) = V ₃ (0) = V ₀ (0) = 0, it is expressed by the equation (3).

[0035]

[Equation 1]

From FIG. 9 and the equation (3), various constants of the equivalent circuit model are as follows.

[0037]

[Equation 2]

Step current (rating) calculated in the same manner
When the average value with the equivalent circuit model constant value at the time of discharge by is the equivalent circuit model standard constant value, the rated capacity shown below is 1
An equivalent circuit model standard constant value of a kW redox flow battery is obtained. Note that R ₂ , R ₃ , τ ₂ , and τ ₃ can be obtained by analyzing the response characteristic curve.

R ₁ = 0.076Ω, R ₂ = 0.01Ω, R
₃ = 0.028Ω τ ₂ = ₃ sec, τ ₃ = 60 sec C ₀ = 20000F, C ₂ = 300F, C ₃ = 2143F i ₀ = 0.536A Next, as described above, when the SOC is low, the monitor cell Since the voltage Vcell exhibits a non-linear characteristic, S
Introduce non-linearity when OC is low. From Figure 7 SOC
It can be seen that dV _cell / dSOC has a negative slope in the low region. It is considered that R _{1 of the} internal resistance model does not depend on SOC, and the nonlinearity is introduced assuming that the internal resistance components R ₂ and R ₃ having a time constant depend on the state.
Non-linear resistance characteristics of dV _{ce ll} / dSOC of FIG 7 R _2, R ₃
The polygonal line approximation is as shown in FIG.

In FIG. 10, R ₂ (t) and R ₃ (t) can be expressed by the following equations, and constants are obtained as follows. Here, the number of cells in series is N.

When V ₀ (t) / N ≧ V _l , R ₂ (t) = r ₂ , R ₃ (t) = r ₃ (6) R when V ₀ (t) / N <V _{l 2 (t) = r 2 ×} {a r × V 0 (t) / N + (1-a r × V l)} R 3 (t) = r 3 × {a r × V 0 (t) / N + ( _{1-a r × V l)} } ... (7) r 2 = 0.01Ω, r 3 = 0.028Ω ... standard constant value V _l = 1.33V ... transition point a _r = -20 to nonlinear state (1 / V) ... The slope of the approximated characteristic straight line in the non-linear state Further, C ₂ (t) and C ₃ (t) are R ₂ (t) and R ₃ obtained by the equations (6) and (7). From (t) and constants τ ₂ and τ ₃ , it is determined by the equation (4). In this way, an equivalent circuit model was obtained.

Since the actual redox flow battery system is a constant power control, a formulation for calculating the input / output current and the terminal voltage with the power as a parameter is applied to the created equivalent circuit model and applied to various simulations. It is possible. When the circuit equation for the redox flow battery equivalent circuit model is solved using the trapezoidal rule (= representing all electric circuits by resistance and power source, past history) used in EMTP and the like, the terminal voltage is expressed by the following equation.

[0043]

[Equation 3]

Generally, the battery power P (t) is equal to the terminal voltage V
(T), internal resistance R, and electromotive force E, V (t) = E +
From R · I (t), P (t) = V (t) · I (t) = (E
+ R · I (t)) · I (t) = R · I (t) ² + E · I
It is represented by (t) (where I> 0 is charged and I <0
Therefore, when the input / output power P (t) is given, the input / output current I (t) can be calculated by the following equation.

[0045]

[Equation 4]

By the above calculation, it is possible to calculate the voltage / current value according to the battery output P (t) for each time step.

FIG. 11 is a block diagram for realizing a simulation method using an electrical equivalent circuit model of a redox flow battery, and FIG. 12 is a diagram showing simulation results.

As shown in FIG. 11, in order to execute the simulation, the calculation system program 100 includes
The equivalent circuit model 101 of the redox flow battery is built in. Then, the equivalent circuit model 101 has t = t _0.
The initial value and the constant are input, and the command value P (t) is given to the calculation system program 100. From the equivalent circuit model 101, the open circuit voltage value V ₀ (t)
And the terminal voltage value V (t) are given to the drive availability determination unit 102. The calculation system program 100 is shown in FIG.
The processing based on the flowchart shown in FIG. 3 is executed, and various quantities such as the terminal voltage V (t) and the operation availability determination result are output.

Thus, when the command value P ₀ (t) is given to the measured values of the terminal voltage V (t), the open circuit voltage V ₀ (t) and the current value I (t), the terminal voltage V ( t) and the open circuit voltage V ₀ (t) can be predicted as shown in FIG. 12, for example.

FIG. 13 is a flow chart showing the operation of simulation using the numerical calculation model of the redox flow battery. 13, in step SP (abbreviated as SP in the figure) 1, the calculation time interval Δt is input to the equivalent circuit model 101, and in step SP2, the constants R ₁ , r ₂ , r of the redox flow battery system that is the secondary battery. ₃ , a _r , V ₁ , N, τ ₂ , τ ₃ , C ₀ , i ₀ ,
V _DCUV , V _DCOV , V _{SOC L} , V _SOCH are equivalent circuit models 10
Input to 1. In step SP3, I (t ₀ ), V ₀ (t ₀ ), V ₂ (t ₀ ), V at t = t _0
3 (t ₀ ) is input to the equivalent circuit model 101 as an initial state.

When these initial values are input, in step SP4, V ₁ (t), R ₂ (t), R in the redox flow battery is calculated by the equivalent circuit model 101.
Various quantities of ₃ (t), C ₂ (t), and C ₃ (t) are calculated.
In step SP5, the input / output command value P (t + Δt)
Is input to the calculation system program 100, and in step SP6, the current value I on the equivalent circuit model 101 is input.
(T), voltage values V ₀ (t), V ₂ (t), V ₃ (t) are used to calculate the current value I (t + Δt).
Calculated by 00.

At step SP7, the terminal voltage V _t (t + Δt) on the equivalent circuit model 101 is calculated from the current value I (t + Δt) calculated as described above using the equation (8).
V ₁ (t + Δt), V ₂ (t + Δt), V ₃ (t + Δt)
Then, the open circuit voltage V ₀ (t + Δt) is calculated. In step SP8, it is determined whether or not the operating conditions V _DCUV <V (t + Δt) <V _DCOV and V _SOCL <V (t + Δt) <V _SOCH are satisfied. If this operating condition is satisfied, step SP9 is performed. Is updated and the process returns to step SP4, and the operations of steps SP4 to SP8 are repeated. If the above operating conditions are not satisfied, the operation is stopped and the calculation ends.

FIG. 14 is a diagram showing a comparison of accumulated losses.
FIG. 15 is a diagram showing a comparison of redox flow battery terminal voltages.

When the redox flow battery was operated in a charge / discharge pattern including overload output as shown in FIG. 14,
Perform a simulation using the numerical calculation logic to calculate the accumulated loss. The charging / discharging pattern was selected such that the terminal voltage fluctuates in the SOC region showing a non-linear characteristic. The measured value and the simulated value of the terminal voltage of the redox flow battery at this time are as shown in FIG.

As is apparent from FIG. 15, the measured value and the simulated value are almost equal, and the standard deviation of the error between the measured value and the simulated value was 0.295V. Further, the battery loss calculated by the simulation is 0.318 kWh, whereas the battery loss calculated from the measured input / output power to the battery and the SOC is 0.327 kW.
Since the error with h was 2.75%, it can be said that the characteristics of the redox flow battery can be evaluated by the redox flow battery equivalent circuit model.

Here, the calculation of the battery loss by the simulation is performed by the following equation in consideration of the equivalent model of FIG.

[0057]

[Equation 5]

By using the redox flow battery equivalent circuit model created as described above, it is possible to continuously calculate the battery states such as the open circuit voltage and the terminal voltage of the battery in response to the redox flow battery output command. become. As a result, when the output command curve from the current point onward is given, the state of the battery can be predicted, and the operation continuable time can be predicted, so that the operating capacity of the battery system for the output command can be calculated.

In actual operation, in addition to performing the predictive control using this method, the terminal voltage and open circuit voltage are constantly monitored,
It is desirable to prevent the system from stopping during continuous overload operation. Further, when the simulation is performed in real time at the same time as the operation of the actual system, it is desirable to appropriately correct the calculated values by using the measured values of voltage and current. By applying this equivalent model to the supply and demand control system, it becomes possible to analyze the degree of contribution of the demand and supply control system that utilizes the overload region of the redox flow battery, the battery efficiency, etc. over several hours. These methods can also be applied to other secondary batteries.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0061]

As described above, according to the present invention, the constant output duration characteristic of the secondary battery is expressed by the first-order lag block formed by the first capacitor and the resistor, and the charging depth at the time of input / output is set to the second By expressing with a capacitor and the self-discharge characteristic with a current source, it is possible to grasp the internal state of the battery when the secondary battery is connected to the power system and output control is performed by this model by calculation. Therefore, it is possible to study specifications when applying a secondary battery to an actual machine and to quantitatively evaluate the merits of output control to the system, and to perform output control that maximizes overload capacity while avoiding system shutdown. Will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a redox flow battery to which the present invention is applied.

FIG. 2 is a diagram showing response characteristics of a redox flow battery system at the time of overload output.

FIG. 3 is a diagram showing a constant output duration characteristic of a redox flow battery system.

FIG. 4 is an equivalent circuit diagram of a redox flow battery according to an embodiment of the present invention.

FIG. 5 is a diagram showing a non-linear resistance characteristic of a redox flow battery.

FIG. 6 is a diagram showing the efficiency of a single battery with respect to the changing cycle of the command value P of the inverter.

FIG. 7 is a diagram showing a relationship between a monitor cell voltage V _cell and SOC for measuring a self-discharge amount.

FIG. 8 is a diagram showing measurement results of a self-discharge amount measurement test.

FIG. 9 is a diagram showing an actual measurement result of a terminal voltage response characteristic in a redox flow battery during charging with respect to a step current.

FIG. 10 is a diagram showing a characteristic of the dV _cell / dSOC characteristic of FIG. 7 which is approximated to a polygonal line by nonlinear resistances R ₂ and R ₃ .

FIG. 11 is a block diagram for realizing a simulation method using an electrical equivalent circuit model of a redox flow battery.

FIG. 12 is a diagram showing a simulation result according to the present invention.

FIG. 13 is a flowchart showing an operation of simulating using a numerical calculation model of a redox flow battery.

FIG. 14 is a diagram showing a comparison of accumulated losses.

FIG. 15 is a diagram showing a comparison of redox flow battery terminal voltages.

[Explanation of symbols]

1,4 Electrolyte tank, 2,5 Circulation pump, 3 Battery cells, 6 Inverter, 7 Detection system, 8 Control system, 10
Redox flow battery, 31 positive electrode chamber, 32 negative electrode chamber,
33 positive electrode, 34 negative electrode, 35 diaphragm, 100
Calculation system program, 101 equivalent circuit model,
102 Operation availability determination unit.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhiro Enomoto             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. (72) Inventor Michio Hirose             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. (72) Inventor Yosei Deguchi             1-3-3 Shimaya, Konohana-ku, Osaka Sumitomo Electric             Ki Industry Co., Ltd. Osaka Works F-term (reference) 5H026 AA10 RR01                 5H027 AA10 KK54                 5H030 AA01 AA06 AA09 AS01 FF43                       FF44

Claims (7)

[Claims] 1. A method of creating an electrical equivalent circuit model in which an internal state of a secondary battery is modeled by an equivalent circuit, wherein a constant output duration characteristic of the secondary battery is determined by a first capacitor and a resistor. A method of creating an electrically equivalent circuit model of a secondary battery, which is characterized by a delay block, a charge depth at the time of input and output is expressed by a second capacitor, and a self-discharge characteristic is expressed by a current source. 2. The electrical constant of the secondary battery according to claim 1, wherein the constant output duration characteristic includes a region having a relatively long duration, a region having a relatively short duration, and a region in the middle. Equivalent circuit model creation method. 3. The first-order lag block includes a resistance component due to charge / ion migration / diffusion of the secondary battery and a resistance component determined by an active material supply inside the cell. A method of creating an electrical equivalent circuit model of a secondary battery according to. 4. The constant of the first-order lag block is simulated by a non-linear resistance depending on a battery voltage.
A method for creating an electrically equivalent circuit model of a secondary battery according to claim 3. 5. A current value is calculated using an arbitrarily set output command value and a voltage value on the electrical equivalent circuit model, and a voltage on the equivalent circuit model used in the next calculation is calculated from this current value. A simulation method using an electrical equivalent circuit model of a secondary battery. 6. The simulation method using an electrically equivalent circuit model of a secondary battery according to claim 5, wherein a part or all of the voltage values are measured values. 7. A current value is calculated using an arbitrarily set output command value and a voltage value on the electrical equivalent circuit model, and the voltage on the equivalent circuit model used in the next calculation is calculated from this current value. A program using an electrical equivalent circuit model of a secondary battery, characterized in that