JP2020134279A - Battery control device - Google Patents

Abstract

To solve the problem of a large calculation load that is caused because battery data cannot be easily modified according to deterioration of the battery.SOLUTION: A parameter calculation part 1203 extracts values of a positive electrode data table 1206 and a negative electrode data table 1207 corresponding to an input battery temperature. The parameter calculation part refers to the values of the positive electrode data table 1206 or the negative electrode data table 1207 and updated parameters, uses formulae (1)-(5) for calculating a charging/discharging amount Q_cell (Ah), OCV_cell (V), a DC resistance Ro_cell (Ω), a polarization resistance Rp_cell (Ω) and a polarization capacity Cp_cell (F). The calculation results are stored in a battery data table 1205. The parameter calculation part 1203 updates initial values held in a parameter holding part 1208 to parameters according to a current battery state estimated by a deterioration state estimation part 1201.SELECTED DRAWING: Figure 2

Description

The present invention relates to a battery control device.

In recent years, the use of battery control devices incorporating a large number of batteries, such as power storage devices for mobile bodies, power storage devices for grid interconnection stabilization, and emergency power storage devices, has been expanding. In order to bring out the performance of these battery control devices, it is necessary to appropriately calculate the charging state (hereinafter, SOC), the deteriorated state (hereinafter, SOH), the maximum current that can be charged and discharged (allowable current value), and the like.

In order to calculate the maximum current at which the battery voltage does not deviate from the upper limit or the lower limit, it is necessary to use the internal state and parameters of the battery such as the open circuit voltage (OCV) of the battery and the internal resistance. In particular, in a power storage device for a mobile body or a system linkage stabilizing power storage device in which an irregular current is constantly flowing, a current is passed in addition to an internal resistance (DC resistance) that causes a voltage change that occurs at the moment when the current is passed through the battery. It is necessary to consider the influence of the internal resistance (polarization resistance) that causes the voltage change when continuing.

Parameters such as DC resistance and polarization resistance generally vary with the SOC and temperature of the battery. Therefore, the battery controller holds as a data table or a function representing the data what values the parameters such as DC resistance and polarization resistance show at various SOCs and temperatures. Then, it is common to estimate the SOC based on the information sent from the cell controller and then specify the parameter value from the data table or function. However, since these parameters are measured in the initial state of the battery, if the battery deteriorates, values different from the actual values will be read from the data table or function, and the SOC, battery voltage value, and allowable current value will be read. Etc. are calculated incorrectly.

A method of updating the data table of the DC resistance component and the polarization resistance component according to the deterioration of the battery has also been proposed. For example, Patent Document 1 has a data table of DC resistance and diffusion coefficient in the initial state, while DC resistance and diffusion coefficient identified by measurement values of battery voltage waveform during charging and discharging and calculation based on a predetermined battery model. A learning-type algorithm has been proposed that updates the data table at the location corresponding to the measured SOC and temperature according to the value of.

Japanese Unexamined Patent Publication No. 2013-44598

When the battery deteriorates, the battery data cannot be easily corrected, and the calculation load is large.

The battery control device according to the present invention is a storage unit that stores positive electrode and negative electrode data including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount for each of the positive electrode and the negative electrode of the battery in the initial state. And, based on the deterioration state estimation unit that estimates the deterioration state of the current battery and the positive electrode and negative electrode data stored in the storage unit, the current deterioration state of the battery estimated by the deterioration state estimation unit is obtained. A parameter calculation unit for calculating battery data of the battery including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount is provided accordingly.

According to the present invention, the data of the battery can be easily corrected according to the deterioration of the battery, and the calculation load for that purpose is small.

It is a block diagram of a battery system. It is a functional block diagram of a battery controller. (A) (B) It is a figure which shows the voltage behavior of a battery when a square wave current is applied to a battery. It is a figure which shows the equivalent circuit model of a battery. It is a figure which shows the positive electrode data table and the negative electrode data table. (A) (B) is a graph showing the discharge amount and polarization resistance of the positive electrode and the negative electrode at 25 ° C. It is a figure which shows the battery data table. It is a figure which shows the example of the battery data table of the polarization resistance of a battery in the initial state of a battery and after deterioration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of the battery system 100. The battery system 100 includes a battery control device 1, an inverter 2, a load 3 such as a motor, and a host controller 4. Since the output voltage of the battery control device 1 is a DC voltage that fluctuates depending on the remaining capacity of the battery, the output current, and the like, it may not be suitable for directly supplying electric power to the load 3. Therefore, in the example shown in FIG. 1, the output voltage of the battery control device 1 is converted into a three-phase alternating current by the inverter 2 and supplied to the load 3. The battery control device 1 and the inverter 2 are controlled by the host controller 4.

The same configuration is used when a DC voltage or other multi-phase AC or single-phase AC is supplied to the load 3. Further, when the load 3 outputs electric power, the electric power output by the load 3 can be stored in the battery module in the battery control device 1 by using the inverter 2 as a bidirectional inverter. Further, by connecting the charging system in parallel with the inverter 2, it is possible to charge the battery module as needed.

The battery control device 1 includes a battery charge rate (SOC) and deterioration rate (SOH) useful for controlling the inverter 2 and the load 3, a maximum charge / discharge current (allowable current value) that can be passed through the battery, a battery temperature, and a battery. Information on the battery status such as the presence or absence of an abnormality is transmitted to the host controller 4. The host controller 4 performs energy management, abnormality detection, and the like based on this information. Further, when the host controller 4 determines that the battery control device 1 should be disconnected from the inverter 2 or the load 3, the host controller 4 transmits a disconnection instruction to the battery control device 1.

The battery control device 1 includes one or more battery modules 11 composed of a plurality of batteries, a battery controller 12 that monitors, estimates, and controls the state of the battery control device 1, and a relay 13 that interrupts the output of the battery control device 1. A current sensor 14 that measures the current flowing through the battery module 11, a voltage sensor 15 that measures the voltage of the battery module 11, and an electric leakage sensor 16 that measures the insulation resistance between the battery control device 1 and the ground. It includes a temperature sensor 17 that measures the battery temperature, and a breaker 18 that is controlled according to the output voltage of the battery control device 1. The battery control device 1 shown in FIG. 1 includes two battery modules 11 connected in series via a circuit breaker 18.

The battery controller 12 includes a CPU 121 that performs various calculations and a storage unit 122 that stores a data table described later.

The battery module 11 has a plurality of unit batteries, and includes a circuit for measuring the temperature inside the battery module 11 and the voltage of each unit battery, and a circuit for charging and discharging each unit battery as needed. This makes it possible to monitor the voltage and adjust the voltage for each unit battery, and to measure the temperature information necessary for estimating the battery state whose characteristics change according to the temperature.

A current sensor 14 and a pair of relays 13 are connected in series to the battery module 11 connected in series. The current sensor 14 measures the current value required to monitor and estimate the state of the battery module 11. By controlling the opening and closing of the pair of relays 13 based on the command of the host controller 4, the output of the battery control device 1 can be cut off or connected. When the voltage of the battery module 11 becomes a high voltage of, for example, 100 V or more, a switch for manually interrupting the power input / output to the battery control device 1 may be added in series with the relay 13. By forcibly shutting off using a switch, it is possible to prevent the occurrence of a short circuit or the like when assembling or disassembling the battery control device 1 or when dealing with an accident of the device equipped with the battery control device 1.

When a plurality of battery modules 17 are connected in parallel, relays 13, switches, and current sensors 14 may be provided in each row, and relays 13, switches, and currents may be provided only in the output portion of the battery control device 1. A sensor 14 may be provided. Further, the relay 13, the switch, and the current sensor 14 may be provided in both the row and the output unit of the battery control device 1.

The relay 13 may be composed of one relay, or may be composed of a main relay, a precharge relay, and a resistor. In the latter configuration, resistors are placed in series with the precharge relay and these are connected in parallel with the main relay. Then, when connecting the relay 13, first connect the precharge relay. Since the current flowing through the precharge relay is limited by the resistors connected in series, the inrush current that can occur in the former configuration can be limited. Then, connect the main relay after the current flowing through the precharge relay becomes sufficiently small. The timing of connecting the main relay may be based on the current flowing through the precharge relay, or the voltage applied to the resistor or the voltage between the terminals of the main relay. Further, the time elapsed since the precharge relay is connected may be used as a reference.

The voltage sensor 15 measures the voltage value required for condition monitoring / estimation of the battery module 11. The voltage sensor 15 is connected in parallel to one or a plurality of battery modules 11. Further, an electric leakage sensor 16 is connected to the battery module 11 to detect a state in which an electric leakage can occur before the electric leakage occurs, that is, a state in which the insulation resistance is lowered, so that the occurrence of an accident can be prevented.

The measured values of the battery module 11, the current sensor 14, the voltage sensor 15, and the leakage sensor 16 are transmitted to the battery controller 12. The battery controller 12 monitors, estimates, and controls the battery state of the battery module 11 based on the received measured value. Here, the control means, for example, charging / discharging of each unit battery for equalizing the voltage of each unit battery, power supply control of each sensor, addressing of each sensor, control of the relay 13 connected to the battery controller 12, and the like. Point to. The CPU 121 performs calculations necessary for monitoring, estimating, and controlling the battery status.

The battery control device 1 may include a fan for cooling the system, and the battery controller 12 may control the fan. When the battery control device 1 performs cooling in this way, it is possible to reduce the amount of communication with the host controller 4.

In the example shown in FIG. 1, the voltage sensor 15 and the leakage sensor 16 are made into separate parts from the battery controller 12 to give a degree of freedom, but the battery controller 12 has the voltage sensor 15 and the leakage sensor 16 built-in. May be. By adopting the built-in configuration, the number of harnesses can be reduced and the time and effort required to install the sensors can be reduced as compared with the case where individual sensors are prepared. However, the built-in sensor may limit the scale (maximum output voltage, current, etc.) of the battery control device 1 that can be supported. In such a case, it is desirable to use a separate component.

FIG. 2 is a functional block diagram of the battery controller 12. The battery controller 12 calculates, for example, an allowable current value. The calculation of the allowable current value is performed by the CPU 121. The CPU 121 includes a deterioration state estimation unit 1201, a charge state estimation unit 1202, a parameter calculation unit 1203, and an allowable current calculation unit 1204 as functional configurations, and as a storage unit configuration, a battery data table 1205, a positive electrode data table 1206, and a negative electrode data. It includes a table 1207 and a parameter holding unit 1208.

Current, voltage, and temperature values are input to the deterioration state estimation unit 1201 and the charge state estimation unit 1202 from a group of sensors such as the current sensor 14, the voltage sensor 15, and the temperature sensor 17.

The deterioration state estimation unit 1201 estimates the state of the battery based on the current I, the voltage V, and the temperature T output from the sensor group. The target to be estimated may arbitrarily select an index indicating the state of the battery, and for example, the decrease in battery capacity is estimated. For example, the following method is used to estimate the decrease in battery capacity.

The charge / discharge amount Q_AB from one time point A to another time point B is integrated. Further, the charge state estimation unit 1202 is referred to, OCV_A at the time point A and OCV_B at the time point B are calculated, and the battery data table 1205 in the initial state is referred to, and the charge / discharge amounts Q_AB corresponding to OCV_A and the charge / discharge corresponding to OCV_B are charged / discharged. Find the quantity Q'_AB. Then, let Q'_AB / Q_AB be the capacity reduction rate. Let this volume reduction rate be SOH. In this embodiment, the capacity reduction rate or the capacity reduction amount Q_deg obtained by multiplying the capacity reduction rate by the initial capacity Q_0 of the battery is used as an index of the deterioration state of the battery.

The SOH may be determined by the rate of increase in resistance. For example, the ratio of the internal resistance in the initial state of the battery to the current internal resistance is defined as the resistance increase rate, and this resistance increase rate is defined as SOH. Further, the SOH of the positive electrode and the negative electrode of the battery may be obtained based on the capacity decrease rate and the resistance increase rate of the positive electrode and the negative electrode of the battery, respectively.

The charge state estimation unit 1202 estimates the charge state of the battery based on the current I, the voltage V, and the temperature T output from the sensor group and the equivalent circuit model of the battery. Here, the equivalent circuit model will be described with reference to FIGS. 3 and 4.

FIG. 3 is a diagram showing an example of the voltage behavior of the battery when a square wave current is applied to the battery. FIG. 3 (A) shows the rectangular wave current I applied to the battery, and FIG. 3 (B) shows the voltage V of the battery. In both cases, the horizontal axis is the elapsed time. When, for example, the square wave current I shown in graph 31 of FIG. 3 (A) is applied to the battery, the voltage V of the battery, that is, the CCV (closed circuit voltage) of the battery is shown in graph 32 of FIG. 3 (B). It changes as shown. As shown in FIG. 3B, this change in voltage V is roughly classified into three components: DC voltage component I × R0, polarization voltage component Vp, and OCV fluctuation component ΔOCV. R0 is a DC resistance component.

The first component, the DC voltage component I × R0, responds instantaneously to a change in the current I. That is, it rises momentarily according to the rise of the current I, changes at a constant level, and then disappears with the fall of the current I. The polarization voltage component Vp, which is the second component, fluctuates with a delay with respect to the change in the current I. That is, it gradually increases after the rise of the current I, and gradually decreases after the fall of the current I. The OCV fluctuation component ΔOCV, which is the third component, represents a change in the OCV of the battery, and corresponds to the difference between the OCV 1 which is the OCV value before the start of charging and the OCV 2 which is the OCV value after the start of charging. This OCV fluctuation component ΔOCV corresponds to the amount of change in the state of charge of the battery according to the amount of charge / discharge.

FIG. 4 is a diagram showing an example of an equivalent circuit model of a battery. In FIG. 4, R0 represents a DC resistance component. By applying the current I to the DC resistance component R0, the DC voltage component I × R0 can be obtained. On the other hand, Rp represents a polarization resistance component and Cp represents a polarization capacitance component, and the polarization voltage component Vp can be obtained from these values, the current I, and the charge / discharge time t. Further, the OCV fluctuation component ΔOCV can be obtained from the amount of change in OCV. Further, from the equivalent circuit shown in FIG. 4, the polarization voltage component Vp shows an exponential variation in the time constant RpCp.

For example, in the first method, the charge state estimation unit 1202 shows a battery data table described later showing the relationship between the SOC and OCV of the battery based on the OCV of the battery obtained by analyzing the CCV of the battery with the equivalent circuit model. The SOC is calculated with reference to 1205. As a second method, the SOC may be calculated based on the relationship between the charge / discharge electricity amount and the SOC based on the charge / discharge electricity amount ΔQ in which the current I is integrated. Alternatively, the SOC may be calculated by combining both expressions. In this embodiment, an example of the first method will be described.

In the positive electrode data table 1206 and the negative electrode data table 1207, the DC resistance component, the polarization resistance component, and the polarization capacitance component in the initial state of the battery are stored in relation to each temperature, charge / discharge amount, and OCV.

FIG. 5 is a diagram showing a positive electrode data table 1206 and a negative electrode data table 1207. The items in the table are temperature T (° C.), charge / discharge amount Qi (Ah), OCVVi (V), DC resistance Roi (Ω), polarization resistance Rpi (Ω), and polarization capacitance Cpi (F). Here, the subscript i in the table indicates either the positive electrode pos or the negative electrode neg. In the positive electrode data table 1206, i is the positive electrode pos, and in the negative electrode data table 1207, i is the negative electrode neg. In FIG. 5, the positive electrode data table 1206 and the negative electrode data table 1207 are shown in a unified manner, but the positive electrode data table 1206 and the negative electrode data table 1207 are provided independently. The positive electrode data table 1206 and the negative electrode data table 1207 may be stored in the form of a data table, or may be stored as a function representing data.

The positive electrode data table 1206 and the negative electrode data table 1207 show that the DC resistance Roi (Ω) at a temperature T (° C.) of T1, charge / discharge amounts Qi of Qi, 1 to Qi, n, and OCV of Vi, 1 to Vi, n. The polarization resistance Rpi (Ω) and the polarization capacitance Cpi (F) are stored. Then, the DC resistance Roi (Ω), the polarization resistance Rpi (Ω), and the polarization capacitance at a temperature T (° C.) up to Tm, a charge / discharge amount Qi of Qi, 1 to Qi, n, and an OCV of Vi, 1 to Vi, n I remember Cpi (F).

6 (A) and 6 (B) are graphs showing an example of the charge / discharge amount (Ah) of the positive electrode and the negative electrode and the polarization resistance Rp at 25 ° C. FIG. 6A is a graph of the positive electrode charge / discharge amount Q_pos (Ah) at 25 ° C. and the polarization resistance Rp_pos in the initial state of the battery, and FIG. 6B is a negative electrode charge / discharge amount Q_neg (B) at 25 ° C. It is a graph in the initial state of the battery of Ah) and the polarization resistance Rp_neg. Although an example of the polarization resistance Rp is shown, the positive electrode data table 1206 and the negative electrode data table 1207 of the battery are similarly created for the DC resistance Roi (Ω) and the polarization capacitance Cpi (F) based on these graphs.

The parameter calculation unit 1203 sets the deterioration state of the battery estimated by the deterioration state estimation unit 1201 and the values of the battery data table 1205 based on the positive electrode data table 1206 and the negative electrode data table 1207, for example, the following equations (1) to (5). ) Is used for calculation.
Q_cell = Q_pos * A_pos + B_pos = Q_neg * A_neg + B_neg ・ ・ ・ (1)
OCV_cell = OCV_pos-OCV_neg ・ ・ ・ (2)
Ro_cell = Ro_pos * D_pos + Ro_neg * D_neg ・ ・ ・ (3)
Rp_cell = Rp_pos * E_pos + Rp_neg * E_neg ・ ・ ・ (4)
Cp_cell = Max (Cp_pos * Rp_pos * F_pos, Cp_neg * Rp_neg * F_neg) / Rp_cell
... (5)

Here, the parameters A_pos, B_pos, A_neg, B_neg, D_pos, D_neg, E_pos, E_neg, F_pos, and F_neg are the rate of change of each component, and their initial values are stored in advance in the parameter holding unit 1208.

The values Q_pos, Q_neg, OCV_pos, OCV_neg, Ro_pos, Ro_neg, Rp_pos, Rp_neg, Cp_pos, and Cp_neg are read from the positive electrode data table 1206 or the negative electrode data table 1207.

Further, in the equation (5), Max (Cp_pos * Rp_pos * F_pos, Cp_neg * Rp_neg * F_neg) means that the larger value is used.

Further, the parameter calculation unit 1203 updates at least one of the parameters A_pos, B_pos, A_neg, B_neg, D_pos, D_neg, E_pos, E_neg, F_pos, and F_neg based on the deterioration state of the battery estimated by the deterioration state estimation unit 1201. .. For example, the capacity reduction amount Q_deg that reflects the deterioration state of the battery is subtracted from the initial value of B_neg, B_neg is updated, and the initial value is used for other parameters. Further, for example, after subtracting the capacity reduction amount Q_deg from the initial value of B_neg and updating B_neg, the temporary battery data table 1205 is calculated using the equations (1) to (5), and is predetermined in the temporary battery data table 1205. The internal resistance of the battery corresponding to OCV (Ro_cell + Ro_cell) is extracted, and the ratio of the internal resistance of the extracted battery to the internal resistance of the initial battery is multiplied by D_pos, D_neg, E_pos, and E_neg, respectively, to D_pos, D_neg, and E_pos. , Update E_neg. Further, for example, the input from the sensor group is processed to construct the observed values of the relationship table of the charge / discharge amount Q_cell of the battery, the OCV: OCV_cell (V) of the battery, and the DC resistance Roi (Ω) and the polarization resistance Rpi (Ω). Then, the charge / discharge amount of the battery Q_cell calculated by the equations (1) to (5), the positive electrode data table and the negative electrode data table, the OCV of the battery: OCV_cell (V), the DC resistance Roi (Ω), and the polarization resistance Rpi ( The parameters A_pos, B_pos, A_neg, B_neg, D_pos, D_neg, E_pos, E_neg, F_pos, and F_neg are calculated and updated so that the calculated values in the relation table of Ω) match the above observed values. In this way, the parameter calculation unit 1203 updates the initial value held in the parameter holding unit 1208 to the parameter of the current battery deterioration state estimated by the deterioration state estimation unit 1201. Then, the calculation is performed using the equations (1) to (5) with reference to the positive electrode data table 1206 or the negative electrode data table 1207. As a result, the charge / discharge amounts Q_pos, Q_neg and OCV_pos, OCV_neg of the positive and negative electrodes of the battery, the charge / discharge amounts Q_pos, Q_neg and the DC resistance components Ro_pos, Ro_neg of the positive electrode and the negative electrode of the battery, Based on the relationship between the charge / discharge amounts Q_pos and Q_neg and the polarization resistance components Rp_pos and Rp_neg and predetermined models, for example, equations (1) to (5), the relationship between the battery charge / discharge amounts Q_cell and OCV_cell, and the battery charge / discharge The relationship between the amount Q_cell and the DC resistance component Ro_cell, the relationship between the battery charge / discharge amount Q_cell and the polarization resistance component Rp_cell, and the correspondence between the positive electrode, the negative electrode, and the battery charge / discharge amounts Q_pos, Q_neg, and Q_cell are determined. The calculation result is stored in the battery data table 1205.

FIG. 7 is a diagram showing a battery data table 1205. The items in the table are temperature T (° C.), charge / discharge amount Q_cell (Ah), OCV_cell (V), DC resistance Ro_cell (Ω), polarization resistance Rp_cell (Ω), and polarization capacitance Cp_cell (F). The battery data table 1205 shows that when the temperature T (° C.) is T1, the charge / discharge amount Q_cell is Q1 to Qn, and the OCV_cell is V1 to Vn, the DC resistance Ro_cell (Ω), the polarization resistance Rp_cell (Ω), and the polarization capacity Cp_cell (F). I remember. Then, until the temperature T (° C.) is Tm, the DC resistance Ro_cell (Ω), the polarization resistance Rp_cell (Ω), and the polarization capacitance Cp_cell (F) at the charge / discharge amounts Q_cell Q1 to Qn and the OCV_cell V1 to Vn are stored. There is.

The permissible current calculation unit 1204 refers to the DC resistance, polarization resistance, and polarization capacity of the battery stored in the battery data table 1205 based on the current battery temperature, and calculates the permissible current of the battery. The calculation of the permissible current is performed in order to maintain the safety of the battery control device 1 by limiting the current so as not to exceed the permissible current value as a part of the safety function for preventing the overvoltage of the battery. An example of calculating the allowable current is shown below.

The allowable charging current is calculated using, for example, the following equation (6).
Icmax = (Vmax-OCV) / R ・ ・ ・ (6)
Here, Vmax is the upper limit voltage and R is the internal resistance of the battery.
The allowable discharge current is calculated using, for example, the following equation (7).
Idmax = (OCV-Vmin) / R ・ ・ ・ (7)
Here, Vmin is the lower limit voltage and R is the internal resistance of the battery.

ここで、Ｒｏ、Ｒｐ、Ｃｐは電池データテーブル１２０５を参照して求める。ｔは時間（秒）である。 The internal resistance R of the battery is calculated using, for example, the following equation (8).

Here, Ro, Rp, and Cp are obtained by referring to the battery data table 1205. t is the time (seconds).

Further, the permissible current calculation unit 1204 calculates the permissible input and the permissible output of the battery based on the DC resistance, the polarization resistance, and the polarization capacity of the battery stored in the battery data table 1205. An example of the operation is shown below.
The permissible input is calculated using, for example, the following equation (9).
Icmax * Vmax ・ ・ ・ (9)
Here, Icmax is the allowable charging current, and Vmax is the upper limit voltage.

The permissible output is calculated using, for example, the following equation (10).
Idmax * Vmin ・ ・ ・ (10)
Here, Idmax is the allowable discharge current, and Vmin is the lower limit voltage.

Next, the operation of this embodiment will be described.
First, in the initial state of the battery, the DC resistance component, the polarization resistance component, and the polarization capacitance component in the initial state of the battery are shown in the positive electrode data table 1206 and the negative electrode data table 1207 shown in FIG. It is stored in advance in association with the relationship of.

Further, the parameter holding units 1208 store in advance the initial values of the parameters A_pos, B_pos, A_neg, B_neg, D_pos, D_neg, E_pos, E_neg, F_pos, and F_neg used in the equations (1) to (5).

The parameter calculation unit 1203 executes the following processing at the time of continuing the use of the battery from the initial state of the battery, for example, at the time of starting the engine, charging the battery with an external power source, or performing a periodic inspection.

First, the parameter calculation unit 1203 updates the initial value held in the parameter holding unit 1208 to a parameter corresponding to the current deterioration state of the battery estimated by the deterioration state estimation unit 1201. Specifically, the parameter calculation unit 1203 extracts the values of the positive electrode data table 1206 and the negative electrode data table 1207 corresponding to the designated battery temperature.

Further, the parameters in the parameter holding unit 1208 are updated according to the current deterioration state of the battery estimated by the deterioration state estimation unit 1201. For example, the capacity reduction amount Q_deg that reflects the deterioration state of the battery is subtracted from the initial value of B_neg, and B_neg is updated. Initial values are used for other parameters. Further, for example, after subtracting the capacity reduction amount Q_deg from the initial value of B_neg and updating B_neg, the temporary battery data table 1205 is calculated using the equations (1) to (5), and is predetermined in the temporary battery data table 1205. The internal resistance of the battery corresponding to OCV (Ro_cell + Ro_cell) is extracted, and the ratio of the internal resistance of the extracted battery to the internal resistance of the initial battery is multiplied by D_pos, D_neg, E_pos, and E_neg, respectively, to D_pos, D_neg, and E_pos. , Update E_neg.

Then, referring to the values of the extracted positive electrode data table 1206 or the negative electrode data table 1207 and the updated parameters, the charge / discharge amounts Q_cell (Ah), OCV_cell (V), and DC resistance are used using the equations (1) to (5). Ro_cell (Ω), polarization resistance Rp_cell (Ω), and polarization capacitance Cp_cell (F) are calculated. The calculation result is stored in the battery data table 1205. In this way, the equivalent circuit parameters of the battery can be easily modified according to the deterioration of the battery, and the calculation load for that can be reduced.

Further, the charge state estimation unit 1202 refers to the battery data table 1205 corresponding to the battery temperature based on the OCV of the battery obtained by analyzing the CCV of the battery with the equivalent circuit model, and refers to the current SOC of the battery. Is calculated. Specifically, the charge state estimation unit 1202 uses the battery temperature, current, and voltage detected by the sensors 14, 15, and 17 and the battery data calculated by the parameter calculation unit 1203 to charge the battery. To estimate. Alternatively, the SOC is calculated based on the relationship between the charge / discharge electricity amount and the SOC based on the charge / discharge electricity amount ΔQ obtained by integrating the current I. Alternatively, both expressions are combined to calculate the SOC.

Next, the allowable current calculation unit 1204 uses the equations (6) to (8) based on the DC resistance, polarization resistance, and polarization capacity of the battery stored in the battery data table 1205 to allow the battery to be charged and discharged. Calculate the current. Further, the allowable input Iin and the allowable output Iout are calculated using the equations (9) to (10).

8 (A) and 8 (B) show an example of the battery data table 1205 of the polarization resistance of the battery in the initial state and after deterioration of the battery. FIG. 8 (A) shows the battery data table 1205 of the polarization resistance of the battery in the initial state, and FIG. 8 (B) shows the battery data table 1205 of the polarization resistance of the deteriorated battery. Here, A_pos, A_neg, B_pos, E_pos, and E_neg do not change before and after deterioration, and in the process that reflects the deterioration state of the battery, B_neg is changed from the initial value B_neg_0 to the value after deterioration B_neg_1 = using the battery capacity reduction amount Q_deg. The case where it is changed to B_neg_0 + Q_deg is shown.

As shown in FIG. 8, it is possible to reflect in the battery data table 1205 that the correspondence between the discharge amounts of the positive electrode and the negative electrode changes due to deterioration, and thereby the discharge amount dependence of the polarization resistance of the battery changes. Similarly, the OCV, DC resistance, and polarization capacity can be calculated by reflecting the deterioration state of the battery.

If you want to convert the charge / discharge amount of the battery to SOC that defines the fully charged state as 100% and the fully discharged state as 0%, for example, OCV_c and OCV_d corresponding to the fully charged state and the fully discharged state are defined respectively. In the data table of charge / discharge amount and OCV reflecting the deterioration state of the battery, Q_c and Q_d of charge / discharge amounts corresponding to OCV_c and OCV_d may be extracted, and the space between Q_c and Q_d may be divided into 100 parts. Further, by extracting the OCV corresponding to each of the 100-divided charge / discharge amounts, it is possible to extract the SOC and OCV data tables that reflect the deterioration state.

According to the embodiment described above, the following effects can be obtained.
(1) The battery control device 1 stores positive electrode and negative electrode data including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount for each of the positive electrode and the negative electrode of the battery in the initial state. Deterioration state estimation based on the data table 1206 and the negative electrode data table 1207, the deterioration state estimation unit 1201 for estimating the deterioration state of the current battery, and the positive electrode and negative electrode data stored in the positive electrode data table 1206 and the negative electrode data table 1207. The battery data (battery data table 1205) of the battery including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount is calculated according to the current deterioration state of the battery estimated by the unit 1201. It includes a parameter calculation unit 1203. As a result, the data of the battery can be easily corrected according to the deterioration of the battery, and the calculation load for that purpose is small.

The present invention is not limited to the above-described embodiment, and other embodiments considered within the scope of the technical idea of the present invention are also included within the scope of the present invention as long as the features of the present invention are not impaired. ..

1 Battery control device 2 Inverter 3 Load 4 Upper controller 11 Battery module 12 Battery controller 13 Relay 14 Current sensor 15 Voltage sensor 16 Leakage sensor 17 Temperature sensor 18 Circuit breaker 100 Battery system 121 CPU
122 Storage unit 1201 Deterioration state estimation unit 1202 Charge state estimation unit 1203 Parameter calculation unit 1204 Allowable current calculation unit 1205 Battery data table 1206 Positive electrode data table 1207 Negative electrode data table 1208 Parameter holding unit

Claims (7)

A storage unit that stores positive and negative electrode data including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount for each of the positive and negative electrodes of the battery in the initial state.
Deterioration state estimation unit that estimates the current battery state,
Based on the positive electrode and negative electrode data stored in the storage unit, the relationship between the DC resistance component and the charge / discharge amount, and the polarization resistance component, according to the current deterioration state of the battery estimated by the deterioration state estimation unit. A battery control device including a parameter calculation unit that calculates battery data of the battery including the relationship between charge and discharge amounts. In the battery control device according to claim 1,
A detector that detects the temperature, current, and voltage of the battery,
It is provided with a charge state estimation unit that estimates the charge state of the battery.
The charge state estimation unit is a battery control device that estimates the charge state of the battery using the temperature, current, and voltage of the battery detected by the detection unit and the battery data calculated by the parameter calculation unit. In the battery control device according to claim 1,
A detector that detects the temperature, current, and voltage of the battery,
It is provided with an allowable current calculation unit that calculates the allowable current or the allowable input / output of the battery.
The permissible current calculation unit calculates the permissible current or permissible input / output of the battery by using the temperature, current, and voltage of the battery detected by the detection unit and the battery data calculated by the parameter calculation unit. Battery control device. In the battery control device according to any one of claims 1 to 3.
The positive electrode and negative electrode data stored in the storage unit are the relationship between the DC resistance component and the charge / discharge amount at one or both of a plurality of temperature levels and current levels, or one or a plurality of temperature levels and current levels. It is data showing the relationship between both of the polarization resistance components and the charge / discharge amount.
The parameter calculation unit is based on the positive electrode and negative electrode data stored in the storage unit corresponding to one or both of the temperature and current of the battery, and the deterioration of the current battery estimated by the deterioration state estimation unit. A battery control device that calculates the battery data including the relationship between the DC resistance component and the charge / discharge amount and the relationship between the polarization resistance component and the charge / discharge amount according to the state. In the battery control device according to claim 4,
The parameter calculation unit is currently estimated by the deterioration state estimation unit based on the positive electrode data and the negative electrode data stored in the storage unit corresponding to one or both of the predetermined temperature level and the current level of the battery. The battery data including the relationship between the DC resistance component and the charge / discharge amount and one or both of the charge / discharge amount and the temperature and current, and the relationship between the polarization resistance component and the charge / discharge amount and one or both of the temperature and current are obtained according to the deterioration state of the battery. Battery control device to calculate. In the battery control device according to any one of claims 1 to 3.
The parameter calculation unit includes at least one of the relationship between the charge / discharge amount of the battery and the OCV, the relationship between the charge / discharge amount of the battery and the DC resistance component, the relationship between the charge / discharge amount of the battery and the polarization resistance component, and the battery. At least one of the relationship between the charge / discharge amount of the positive electrode and the negative electrode and OCV, the relationship between the charge / discharge amount of the positive electrode and the negative electrode of the battery and the DC resistance component, and the relationship between the charge / discharge amount of the positive electrode and the negative electrode of the battery and the polarization resistance component. A battery control device that compares and determines the correspondence between the positive electrode, the negative electrode, and the charge / discharge amount of the battery based on a predetermined model. In the battery control device according to claim 1,
The deterioration state estimation unit estimates the amount of decrease in the capacity of the battery,
The parameter calculation unit is a battery control device that calculates the battery data by modifying the positive electrode data and the negative electrode data stored in the storage unit using the capacity reduction amount of the battery.

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