JP2012029417A - Battery control system and battery control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve SOC equalization which can flexibly correspond to the way a battery is used.SOLUTION: In a battery control system configured by an equalization circuit for equalizing an SOC of a single battery to configure a multiple series battery and by a controller to manage the multiple series battery, the controller calculates the SOC of the multiple series battery, and the residence time of the SOC of the multiple series battery is detected from the SOC shift. An SOC dispersion degree of each single battery is detected and SOC equalization control is performed when a current flowing into the multiple series battery is the same as or lower than a prescribed value so that the SOC of single batteries to configure the multiple series battery are matched within the longest residence SOC range of the multiple series battery. Thus, within the most used SOC range, the SOC of the single batteries to configure the multiple series battery can be matched.

Description

  The present invention relates to a battery control system for a power supply device using power storage means such as a lithium secondary battery, a nickel metal hydride battery, a lead battery, and an electric double layer capacitor.

  In a power supply device, a power storage device, and the like using a power storage unit such as a battery, various battery control controllers for optimally managing the power storage unit are mounted. As the state of the power storage means managed by the battery controller, the state of charge (SOC) or remaining capacity indicating how much is charged or how much charge can be discharged remains, A typical example is the state of health indicating the degree of deterioration or weakness or the degree of deterioration.

  When the power storage means is configured to include serial connection, self-discharge exists in the power storage means, and individual differences exist in the self-discharge. Therefore, it is necessary to consider the occurrence of SOC variation between the power storage means. When this SOC variation occurs, charging is stopped with a battery having a high SOC during charging, and discharging is limited with a battery having a low SOC during discharging, and the performance of the power storage means may not be maximized. . Furthermore, under a situation where the progress of deterioration varies greatly depending on the SOC, maintaining the state in which the SOC varies causes the occurrence of SOH variations between the power storage means. That is, in order to optimally manage the power storage means including the series connection, it is necessary to equalize the SOC to distribute the SOC of each power storage means in a certain range. When equalizing the SOC of the power storage means, it is necessary to detect the SOC for each power storage means and grasp how much the SOC varies. And about the electrical storage means with high SOC, it discharges using the equalization circuit comprised by the resistance and switch connected in parallel with the electrical storage means, and it matches with the state of the electrical storage means with low average SOC or SOC.

  As a method of equalizing the SOC of a multi-series battery, for example, as disclosed in Patent Document 1, the voltage of all the single cells is detected at the time of start-up, converted to SOC, and the average value of SOC is calculated. For a single battery in which the difference between the calculated SOC and the calculated average value of the SOC exceeds the set value, the bypass time corresponding to the amount of electricity corresponding to the difference between the average value of the SOC and the SOC and the corresponding bypass control switch are controlled to be in the ON state. A scheme has been proposed.

JP 2009-178040 A

  However, the process of equalizing the SOC of the power storage means varies depending on how the power storage means is used. Even in the case of power storage means of the same application, the usage varies depending on the installation location and the user, so it has been difficult to realize SOC equalization according to the actual usage of the power storage means.

  That is, even if the method of detecting the SOC of all the single cells and improving the SOC variation as in the above-mentioned Patent Document 1, the SOC is not sufficiently equalized in the maximum usage range, or the equalization control is performed. It has been difficult to achieve appropriate SOC equalization according to how the power storage means is used, such as an increase in loss due to repetition.

  An object of the present invention is to achieve SOC equalization according to how a multi-series battery is used, to achieve uniform SOC in the maximum usage range, and to reduce loss due to repeated equalization control. A battery control system and a control method thereof are provided.

  In a preferred embodiment of the present invention, in a battery control system comprising an equalization circuit for equalizing the SOC of single cells constituting a multi-series battery and a controller for managing the multi-series battery, the multi-series battery The SOC stay time of the multi-series battery is detected from the transition of the SOC of the multi-series battery, the SOC is discretized at a predetermined step size, the SOC range having a high stay probability is detected, and the SOC of the single battery is the SOC having the high stay probability. Equalization control is executed so as to equalize the SOC of the multi-series battery when it is within the range.

  Here, it is described that “equalization control is performed so as to equalize the SOC of the multi-series batteries within the high stay probability SOC range”. This is because the SOC sequentially obtained by the battery controller is the high stay probability SOC. It does not mean that the equalization control is executed only when it is within the range. That is, the obtained SOC detects an SOC variation between the power storage means within the high stay probability SOC range, and obtains an equalization execution value that can be improved, and within the high stay probability SOC range or outside the high stay probability SOC range Equalization control is executed based on the equalization execution value. The SOC of the multi-series battery is not equal outside the high stay probability SOC range, but the SOC of the multi-series battery is equalized when entering the high stay probability SOC range by subsequent operation. Means equalization control.

  In a preferred embodiment of the present invention, when the obtained SOC is within the high stay probability SOC range, and the current flowing into and out of the multi-series battery becomes equal to or less than a predetermined value, an equalization execution value is obtained and the high stay is obtained. Equalization control is executed based on the equalization execution value within the probability SOC range or outside the high stay probability SOC range. Of course, in applications where the SOC stays in the high stay probability SOC range for a long time, when the SOC is within the high stay probability SOC range, the execution value of the equalization is obtained and equalization control is performed within the high stay probability SOC range. It is also possible to execute.

  In a specific embodiment of the present invention, the SOC of a single battery or a multi-series battery is calculated, and the residence time of the SOC of the multi-series battery is detected from the SOC transition. In the SOC range (high residence probability SOC range) with the highest probability as the SOC stay time of a single battery or multi-series battery, when the current flowing into and out of the multi-series battery becomes a predetermined value or less, the SOC variation degree of each single battery is determined. SOC equalization control that can detect and improve this is executed.

  According to a preferred embodiment of the present invention, there is provided a battery control system or a control method thereof capable of appropriately realizing SOC equalization control within the most used SOC range with less loss depending on how a multi-series battery is used. it can.

1 is an overall configuration block diagram of a battery system according to an embodiment of the present invention. It is a block diagram for demonstrating the communication form of the battery module and battery controller by one Example of this invention. It is a block diagram for explaining a module control circuit built in a battery module according to an embodiment of the present invention. It is explanatory drawing of the battery model by one Example of this invention. It is a relation characteristic figure of OCV and SOC of a battery which can be adopted in one embodiment of the present invention. It is a processing flow of SOC equalization control which the battery controller which can be employ | adopted by one Example of this invention performs. It is an image figure of SOC equalization control which can be employ | adopted with one Example of this invention. It is an image figure of SOC change for demonstrating SOC equalization control by one Example of this invention. It is explanatory drawing of the view of the SOC residence time calculated | required from the SOC transition in the Example of this invention. It is explanatory drawing of the other example of SOC residence time calculated | required from SOC transition in the Example of this invention. It is a processing flow for demonstrating operation | movement of the battery controller in Example 1 of this invention. It is a figure which shows the effect of the SOC equalization control which the battery controller in Example 1 of this invention performs. It is a processing flow for demonstrating operation | movement of the battery controller in Example 2 of this invention. It is a figure which shows the effect of the SOC equalization control which the battery controller in Example 2 of this invention performs. It is a processing flow for demonstrating a part of operation | movement of the battery controller in Example 3 of this invention. It is a processing flow for demonstrating operation | movement of the battery controller in Example 3 of this invention. It is a figure which shows the effect of the SOC equalization control which the battery controller in Example 3 of this invention performs. It is a figure explaining the processing content of SOC equalization control which the battery controller in Example 4 of this invention performs.

  In FIG. 1, the whole structure of the battery system in this invention is shown. A battery module 101 composed of a plurality of single cells; a current detection means 102 for detecting a current flowing into and out of the battery module 101; and a voltage detection means 103 for detecting a voltage between both terminals of one or more battery modules 101; A battery controller 104 that performs processing based on at least information from the battery module 101, a current value detected by the current detection unit 102, and a voltage value detected by the voltage detection unit 103, and one or more battery modules 101; The switch unit 105 is detachable, and the battery system controller 106 manages the entire system in which one or more battery modules 101 are connected in parallel via the switch unit 105. The battery system controller 106 collects information on all the battery modules 101 via the battery controller 104 and transmits the information to the outside of the battery system. It is also possible to send a command to each battery controller 104 based on information from outside the battery system or by the battery system controller 106 itself.

  FIG. 2 shows a detailed configuration of the battery module 101 according to the present invention and a communication form with the battery controller 104. The battery module 101 includes one or more single cells 201 and a module control circuit 202. Here, the battery module 101 is configured by connecting two unit cells 201 in series and installing one module control circuit 202 therein. The battery modules 101 are further connected in series to increase the voltage, and the battery controller 104 manages the entire one or more battery modules 101.

  The unit cell 201 built in the battery module 101 is an electricity storage device that can store and discharge electricity. Lead-acid batteries, electric double layer capacitors, nickel metal hydride batteries, lithium ion batteries, etc. are representative examples. In this embodiment, two unit cells 201 are connected in series, but the number of series cells may be increased to increase the voltage. Also, the number of series of battery modules 101 may be one or more, and when it is desired to increase the voltage, the battery modules 101 can be connected in series until a desired voltage is obtained.

  A communication mode between the battery controller 104 and the module control circuits 202a and 202b in this embodiment will be described. The battery controller 104 and the module control circuits 202a and 202b are connected in a loop by a signal communication line. Here, the module control circuit 202 will be described assuming that the reception signal communication line is 203a and the transmission signal communication line is 203b. This loop connection may be referred to as a daisy chain connection, a daisy chain connection, or a random connection. In the present embodiment, the above connection and signal transmission / reception modes are adopted. However, if the battery controller 104 and one or more module control circuits 202 are connected to realize signal transmission / reception, other connection modes may be adopted. Is possible.

  The signal transmitted from the battery controller 104 is input to the module control circuit 202 a, the output of the module control circuit 202 a is input to the module control circuit 202 b, and the output of the lowest module control circuit 202 b is transmitted to the battery controller 104. Signals are transmitted / received between the battery controller 104 and the module control circuit 202 via the insulating element 204, and signals are also transmitted / received between the module control circuit 202 via the insulating element 204. Note that the insulating element 204 can be omitted depending on the system configuration. Furthermore, in this embodiment, the insulating element 204 is mounted on the module control circuit 202, but the insulating element 204 may be installed by providing another substrate different from the module control circuit 202.

  Details of the module control circuit 202 will be described with reference to FIG. The module control circuit 202 includes a resistor 301 connected in parallel to one unit cell 201 and an integrated circuit 302 (the insulating element 204 is omitted). The integrated circuit 302 includes a switch 303, a voltage detection circuit 304 for detecting the voltage of the unit cell 201, a control circuit 305 for controlling the entire integrated circuit 302, and a signal input / output circuit 306 for transmitting / receiving signals to / from the outside. It consists of

  The resistor 301 and the switch 303 are used to equalize SOC or voltage variation between the cells 201 connected in series. The voltage detection circuit 304 detects the voltage of the unit cell 201, and by turning on the switch 303 corresponding to the unit cell 201 that is determined to have a high SOC or voltage from the result, the unit cell 201 having a high SOC or voltage is detected. The stored energy is consumed by the resistor 301. As a result, the SOC or voltage between the plurality of single cells 201 can be equalized. Detailed processing contents for SOC or voltage equalization between the plurality of single cells 201 will be described later.

  A unique address is set for each integrated circuit 302, and the battery controller 104 transmits a command signal including the address of the integrated circuit 302 to which a command is to be issued, so that processing is performed for each integrated circuit 302. Can do. For example, when it is desired to acquire the voltage only for the unit cell 201 managed by a certain integrated circuit 302, the battery controller 104 transmits a voltage acquisition command including the address of the integrated circuit 302 that manages the unit cell 201 that is a voltage acquisition target. In this way, the voltage acquisition result of the unit cell 201 of the integrated circuit 302 having the address passes through the communication line 307 between the integrated circuits 302, and finally passes between the module control circuits 202, so that the battery controller 104. Similar processing can be performed for energy consumption using the resistor 301 of the unit cell 201 by the operation of the switch 303 described above. The battery controller 104 transmits an equalization command signal including the address of the integrated circuit 302 that manages the unit cell 201 that has been determined to have a high SOC or voltage. Thereby, only the switch 303 built in the integrated circuit 302 that manages the unit cells 201 to be equalized can be turned on.

  In the present embodiment, a single integrated circuit 302 is provided for one unit cell 201, and two module units are provided as basic units to construct a module control circuit 202 that manages the two unit cells 201. Said. The present invention is not limited to this, and one integrated circuit 302 can be provided for a plurality of unit cells 201. For example, in the case of a configuration in which one integrated circuit 302 is provided for two unit cells 201, the module control circuit 202 that manages the two unit cells 201 is equipped with one integrated circuit 302. When a plurality of unit cells 201 are managed by a single integrated circuit 302, the integrated circuit 302 includes switches 303 as many as the number of unit cells 201 to be managed, and includes only the number of unit cells 201 that also manage the voltage detection circuit 304. Let Alternatively, the voltage of all the single cells 201 is detected by one voltage detection circuit 304 by sequentially switching the single cells 201 to be detected. If the voltage of all the cells 201 to be managed can be detected by the module control circuit 202 and the SOC or voltage can be equalized by individually adjusting the voltage or SOC of the cells 201, the integrated circuit 302 and the module control circuit 202 may have any configuration.

  The battery controller 104 includes information from the module control circuit 202 configured mainly by the integrated circuit 302, current values input / output to / from the battery module 101 acquired by the current detection unit 102, and one or more acquired by the voltage detection unit 103. Based on the voltage value of the battery module 101, the state of the unit cell 201 or the battery module 101 is detected. The state of the unit cell 201 or the battery module 101 includes SOC, SOH, current and power that can be input / output, an abnormal state of the unit cell 201 or the battery module 101, and the like. Below, the detail of the detection method of SOC which the battery controller 104 performs is demonstrated.

  FIG. 4 is a circuit diagram showing an equivalent circuit of the unit cell 201. In FIG. 4, 401 is an electromotive force (OCV), 402 is an internal resistance (R), 403 is an impedance (Z), and 404 is a capacitance component (C). This is represented by a series connection of a parallel connection pair of an impedance 403 and a capacitance component 404, an internal resistance 402, and an electromotive force 401. When the current I is applied to the unit cell 201, the inter-terminal voltage (CCV) of the unit cell 201 is expressed by (Equation 1).

CCV = OCV + IR + Vp …………………………………… (Formula 1)
Here, Vp is a polarization voltage and corresponds to the voltage of a parallel connection pair of Z and C.

  The OCV is used for the calculation of the SOC (charged state), but it is impossible to directly measure the OCV when the unit cell 201 is charged / discharged. Therefore, the OCV is calculated by subtracting the IR drop and Vp from the CCV as shown in (Equation 2).

OCV = CCV-IR-Vp …………………………………… (Formula 2)
R and Vp are characteristic information of the cell 201 stored in advance in the battery controller or obtained in real time. Since it has different values depending on the SOC, temperature, SOH, etc. of the unit cell 201, a highly accurate OCV can be obtained by mounting the characteristic information as a table or function according to the SOC, temperature, SOH, etc. When the characteristic information is properly used according to the temperature, a temperature detecting means for detecting the temperature of the unit cell 201 is required (not shown).

  The current value I can be obtained by the current detection means 102, and the CCV can be obtained by the voltage detection circuit 304 in the integrated circuit 302. When the OCV is calculated by (Equation 2) using CCV, I, R, and Vp, as shown in FIG. 5, by using the relationship between the OCV and the SOC stored in advance in the battery controller 104, The SOC (SOCv) of the unit cell 201 can be detected.

  Although the SOC detection using the above-described equivalent circuit has been described for the single cell 201, the battery module 101 can also be targeted. In this case, the total value of the voltage acquisition results for each cell 201 by the voltage detection circuit 304 in the integrated circuit 302 or the voltage acquisition result by the voltage detection means 103 is used as the CCV. The characteristic information such as the relationship between R, Vp, OCV, and SOC uses values in units of battery modules 101. Further, the parameters used in the above-described calculation may be averaged by dividing by the number of unit cells 201 constituting the battery module 101 and managed as the average SOC of the unit cells 201.

  In place of the SOC (SOCv) based on the above-described equivalent circuit, the SOCi of (Equation 3) can also be used. Here, SOC0 is the SOC at the start of calculation, I is the current value detected by the current detection means 102, and Qmax is the capacity when the unit cell 201 or the battery module 101 is fully charged.

SOCi = SOC0 + 100 × ∫Idt / Qmax (Equation 3)
Furthermore, as shown in (Equation 4), the SOC final result based on the equivalent circuit using (Equation 2) and the SOCi based on current integration using (Equation 3) are combined into the SOC final It is good also as a value (W is a weighting coefficient). When using (Equation 4), SOC0 used for obtaining SOCi in (Equation 3) may be the previous calculation result of SOCc in (Equation 4).

SOCc = W × SOCv + (1-W) × SOCi (Equation 4)
In the above, the SOC detection method of the unit cell 201 or the battery module 101 performed by the battery controller 104 has been described. However, if the SOC of the unit cell 201 or the battery module 101 can be detected, a method other than the aforementioned SOC detection method is adopted. You can also Furthermore, in the situation where the unit cell 201 or the battery module 101 is not charged / discharged, the result of simply detecting the voltage of the unit cell 201 or the battery module 101 is referred to as OCV, and the relationship between the OCV and the SOC in FIG. It is possible to obtain SOC.

  The SOC equalization processing performed by the battery controller 104 will be described using the operation flow of FIG. The battery controller 104 transmits a command to each module control circuit 202, and the module control circuit 202 transmits the acquired voltage of each cell 201 to the battery controller 104. The battery controller 104 converts the acquired voltage of each cell 201 into SOC using the relationship of FIG. 5 (process 601). As described above, in a situation where the unit cell 201 or the battery module 101 is not charged / discharged, the result of simply detecting the voltage of the unit cell 201 or the battery module 101 can be OCV. The voltage of the unit cell 201 acquired under the conditions is handled.

  The condition for the current to be equal to or lower than the predetermined value is before or after using the battery module 101 or when the switch means 105 is in an open state. When the switch means 105 is partially opened, only the battery controller 104 in the open state treats the voltage of each unit cell 201 constituting the battery module 101 to be managed as OCV and converts it into SOC. When the current flowing into and out of each battery module 101 is weak and the current value detected by each current detection means 102 is smaller than a predetermined threshold value, the voltage of each cell 201 constituting the battery module 101 is treated as an OCV and is used as an SOC. It may be converted.

  Subsequently, the battery controller 104 detects the lowest SOC from the obtained SOC of each unit cell 201, and determines this lowest SOC as a target SOC for SOC equalization (process 602). Then, the battery controller 104 calculates the degree of deviation of each unit cell 201 from the minimum SOC when the minimum SOC is used as a reference. For example, when the unit cell 201b of FIG. 2 has the lowest SOC, the degree of deviation (ΔSOC) of the other unit cells 201 from the lowest SOC is calculated by the following formula. Since the same battery cell 201b is subtracted, the degree of deviation ΔSOC from the lowest SOC is naturally zero.

ΔSOC of unit cell 201a = SOC of unit cell 201a−SOC of unit cell 201b
ΔSOC of unit cell 201c = SOC of unit cell 201c−SOC of unit cell 201b
ΔSOC of unit cell 201d = SOC of unit cell 201d−SOC of unit cell 201b
The battery controller 104 consumes ΔSOC of each unit cell 201 by the resistor 301 mounted on the module control circuit 202, and performs control to match the minimum SOC (in the example, the SOC of the unit cell 201b). In other words, the battery controller 104 turns on the switch 303 for connecting the unit cell 201 and the resistor 301 in parallel for a time during which ΔSOC can be consumed.

  The battery controller 104 obtains ΔSOC of each unit cell 201 by the above formula, obtains the ON time of the switch 303 that can be eliminated by energy consumption in the resistor 301, and uses this as the execution value of the SOC equalization in each unit cell 201. (Process 603). When the required ON time of the switch 303 corresponding to each obtained unit cell 201 is obtained, the battery controller 104 sends an equalization command to the module control circuit 202 to match the SOC of each unit cell 201 with the unit cell 201b. The execution of the conversion is started (process 604).

  FIG. 7 shows the SOC of each unit cell 201 before and after the SOC equalization performed by the battery controller 104. The equalization is performed by lowering the SOC of the other unit cell 201 to the SOC of the unit cell 201b which is the lowest SOC. As a result, the SOC variation caused by the individual difference of the self-discharge between the single cells 201, the current consumption of the module control circuit 202, the individual difference of the dark current, etc. is improved. Can be used optimally. The SOC of the unit cells 201 is substantially equal, centering on the lowest SOC at which the switch means 105 is opened or the current flowing into and out of the battery module 101 is weak. Since the measurement error is included in the result of detecting the voltage of the unit cell 201 by the voltage detection circuit 304, each SOC of the unit cell 201 has an influence as the SOC error. As a result, if the SOC of the other unit cell 201 is completely adjusted centering on the lowest SOC when the switch means 105 is opened or the current flowing into and out of the battery module 101 is weak, the measurement error amount of the voltage detection circuit 304 is obtained. The equalization of the unit cells 201 can be realized within the SOC error. In other words, the SOC of the true unit cell 201 centering on the lowest SOC can be distributed within the SOC error resulting from the measurement error of the voltage detection circuit 304. Alternatively, it is possible to adopt a margin within a range that does not cause individual differences in the life even if they are generated between the unit cells 201, and the SOC can be equalized by an amount exceeding this margin.

  FIG. 8 is a diagram for explaining a problem of conventional SOC equalization control.

  The SOC obtained by detecting the SOC variation (ΔSOC) and obtaining the equalization execution value (ON time of the switch 303) for improving the SOC variation is referred to herein as “equalization determination SOC”. The comparison result of equalization control based on the equalization execution value obtained by the equalization determination SOC is shown.

  In order to simplify the explanation, a configuration in which two unit cells 201a (small full charge capacity) and two unit cells 201b (large full charge capacity) are connected in series was used. In addition, the change in SOC according to the time during constant current discharge when the equalization determination SOC is (a) high, (b) intermediate, and (c) low is shown as an example.

  FIG. 8A shows an example in which the equalization determination SOC is 80%. That is, the equalization execution value is obtained when the SOC is 80%, and the equalization control is executed based on this value (the process of FIG. 6 is executed when the SOC is 80%). As a result of the equalization control, the SOC is equalized most at SOC 80%, but due to the individual difference of the full charge capacity existing between the two unit cells 201, when the constant current discharge leaves the SOC 80%, the SOC variation (If the full charge capacity is small, the SOC change is large, and the full charge capacity is large, the SOC change is small). Similarly, in FIGS. 8B and 8C, both SOCs are equal in the equalization determination SOC, and due to individual differences in the full charge capacity, SOC variation occurs when the SOC is separated from the equalization determination SOC (both SOCs are Although it is said that they coincide with each other, actually, the SOC of the unit cells 201 is distributed within the SOC error corresponding to the measurement error of the voltage detection circuit 304 described above).

  For example, when the processing of FIG. 6 is applied in the vicinity of the SOC at time T1 in FIG. 8A, equalization is performed to match the SOC (point b) of the unit cell 201b with the SOC (point a) of the unit cell 201a. A value is determined. If the equalization control is performed based on this, the SOC of the unit cell 201b decreases and coincides with the SOC of the unit cell 201a in the vicinity of the SOC at the time point T1, and at the same time, the SOC is charged to SOC 80%, which is the past equalization determination SOC. In this case, SOC variation occurs between the two unit cells 201 (results similar to FIG. 8C). Further, when the equalization control value is obtained by obtaining the equalization execution value at the SOC 80%, both SOCs coincide again at the SOC 80%, and the SOC variation occurs in the vicinity of the SOC at the time point T1. Since the equalization control is realized by consuming the energy of the unit cell 201 having a high SOC with the resistor 301, the energy loss increases when the equalization control according to the change of the equalization determination SOC is repeatedly performed. Resulting in.

  In order to optimally perform the SOC equalization control, it is important to perform the SOC equalization in which SOC range between SOC0 to 100% and perform the SOC equalization.

  Therefore, the battery controller 104 in the present embodiment has a function of monitoring the SOC transition of the unit cell 201 or the battery module 101. The equalization determination SOC is determined according to how the unit cell 201 or the battery module 101 is used, and the SOC equalization is optimally performed according to how the unit cell 201 or the battery module 101 is used.

  As an example, FIG. 9 shows an explanatory diagram of a method for monitoring the SOC transition of the battery controller 104 according to the present invention. The battery controller 104 monitors the SOC transition of the battery module 101 ((a) in FIG. 9), and extracts the characteristics of how the battery module 101 is used as the SOC stay time (FIG. 9 (b)). Specifically, the SOC of the battery module 101 is expressed with a reduced resolution of 1%, 5%, 10%, and the like. For example, in the case of 10% increments, it is between SOC 40-50% or SOC 50-60%. A counter is provided in each range, such as between, and when the SOC is between SOC 40-50% and a predetermined time has elapsed, the counter for SOC 40-50% is incremented. Further, when the SOC increases with charging and enters a range of SOC 50-60% and a predetermined time elapses, the counter for SOC 50-60% is incremented. On the contrary, when the SOC is reduced by discharging and the SOC enters the range of SOC 30-40%, the counter for SOC 30-40% is incremented, and the SOC stay time from the SOC transition according to the above-described time is increased. Repeat the extraction process. By using the value of the counter provided every 10%, a histogram with the horizontal axis SOC and the vertical axis SOC stay time as shown in FIG. 9B can be created. Note that the increment used in the monitoring of the SOC transition is 10% in the above description, but this may be matched with the range width of the equalization determination SOC set in advance as an initial value. For example, when the equalization determination SOC preset as an initial value in the battery controller 104 is 20% as the SOC width, such as 40-60% or 50-70%, the monitoring width of the SOC stay time is also automatically set. It can be 20%. Alternatively, the step size used in the monitoring of the SOC transition is determined from the SOC variation degree of the individual difference of the full charge capacity of the unit cell 201 that occurs when the SOC changes by the step size after performing the SOC equalization. be able to. Furthermore, it may be determined in consideration of the influence on the life of the unit cell 201 when the SOC varies by the step size. It is also possible to determine based on the SOC variation degree of the unit cell 201 that is allowed as the battery system. In addition, the voltage measurement accuracy of the voltage detection circuit 304, the SOC detection accuracy based thereon, and the like may be taken into consideration when determining the step size. In the above description, the creation of a histogram is taken as an example, but a method of calculating a probability distribution can also be adopted.

  In the above description, the method for monitoring the SOC transition of the battery module 101 has been described. However, when the SOC is sequentially calculated and updated for each unit cell 201, the above-described processing is performed for each unit cell 201, and each unit cell 201 is processed. 9 may be used to extract the features of how it is used. Eventually, it is a feature of the final usage by totaling the stay time corresponding to the SOC range created for each unit cell 201 for all unit cells 201 minutes.

  The battery controller 104 confirms the histogram of the SOC stay time in each SOC range created by the above-described method, and determines the most stayed SOC (long-term stay SOC) of the unit cell 201 or the battery module 101 as the equalization determination SOC. . In FIG. 9B, the equalization determination SOC is 70-80%.

  In addition, it is also possible to reflect the influence of deterioration according to the SOC determined by the characteristics of the unit cell 201 on the above-described histogram showing the SOC stay time. For example, when the deterioration is accelerated when the SOC is high, a weight parameter indicating the influence of the deterioration is prepared according to each SOC range, and the weight parameter has a larger value as the SOC becomes higher. From the result obtained by multiplying the time for each SOC range described above by the weight value indicating the influence of deterioration prepared for each SOC range, the largest value can be used as the equalization determination SOC. In FIG. 9C, the equalization determination SOC is moved to 80-90% by this weight.

  The weighting factor considering the deterioration for each SOC range described above may be determined with reference to a storage test or a cycle test result of the unit cell 201 or the battery module 101.

  In addition, as shown in FIG. 10, when two peaks exist in the histogram showing the SOC stay time, the SOC that affects the deterioration is adopted. For example, when deterioration is accelerated when SOC is high, the higher SOC is simply set as the equalization determination SOC. Alternatively, the equalization determination SOC may be determined from the result obtained by multiplying the weight coefficient corresponding to the SOC in consideration of the above-described deterioration.

  Through the above-described processing of the battery controller 104, the longest staying SOC of the unit cell 201 or the battery module 101, and the SOC reflecting the parameter considering the influence of deterioration are set as the equalization determination SOC, and this equalization determination SOC is in the state. Sometimes, the equalization control is executed by obtaining the execution value of the SOC equalization so that the SOCs of the single cells 201 coincide with each other.

  The initial value of the equalization determination SOC may be set in advance in the battery controller 104 before determining the equalization determination SOC. When the equalization determination SOC is determined by the above-described processing, the initial value of the equalization determination SOC is overwritten, and a new equalization determination SOC is adopted and used for SOC equalization control. For example, when the equalization determination SOC is initially set to a low value and a higher equalization determination SOC is obtained by the above-described processing, the higher equalization determination SOC is overwritten. The equalization judgment SOC is used. Similarly, the high equalization determination SOC that is initially set is also overwritten with the low equalization determination SOC when the low equalization determination SOC is obtained by the above-described processing, and the low equalization determination that is overwritten thereafter. SOC is used.

  According to the present embodiment, the plurality of single cells 201 constituting the battery module 101 are reflected by the 70-80% longest stay SOC illustrated in FIG. In the 80-90% equalization control SOC illustrated in FIG. 9C with correction, it is possible to realize the SOC equalization control that most reduces the SOC variation. For this reason, variation in deterioration among the plurality of single cells 201 during use of the battery module 101 can also be reduced.

  As a result, it is possible to determine the equalization determination SOC optimally according to the usage of the battery module 101 and to realize the SOC equalization control according to the usage of the battery module 101.

  FIG. 11 is a processing flow of SOC equalization control according to the first preferred embodiment of the present invention.

  As described above, when the SOC of the unit cell 201 or the battery module 101 enters the equalization determination SOC, an execution value of the SOC equalization is obtained, and the SOC equalization control is executed based on this. The contents of the SOC equalization processing of the battery controller 104, which summarizes the SOC equalization control processing according to the first embodiment, will be described with reference to FIG.

  The battery controller 104 monitors the SOC transition of the unit cell 201 or the battery module 101 by the above-described processing, and the result of correcting the deterioration parameter in the longest stay SOC or the longest stay SOC is “equalization determination”. SOC ". Thereafter, the SOC of the unit cell 201 or the battery module 101 is monitored, and when the SOC of the unit cell 201 or the battery module 101 becomes the equalization determination SOC, the process proceeds to the next step (processing 1101).

  Here, as a determination method of whether or not the equalization determination SOC is reached, for example, when the longest SOC stay time is counted in the range of SOC 40-50%, and the equalization determination SOC becomes 40-50% SOC Determines that the battery module 101 is in the state of equalization determination SOC when the SOC of the battery module 101 is in the range of 40-50%. The method of determining that the equalization determination SOC has been reached is not limited to the above. For example, when the longest SOC stay time is counted in the range of SOC 40-50%, a 5% margin outside the SOC range of the battery module 101 In addition, an adjustment such as determining the “equalization determination SOC” within the 35-55% range may be made, and conversely, a determination threshold value is provided inside 40-50% within the determinable range. May be.

  Further, since the SOC of each unit cell 201 varies, it is assumed that the state of the equalization determination SOC is in the state when the minimum SOC of them becomes the equalization determination SOC or when the average SOC becomes the equalization determination SOC. You may judge. A method of determining that the state of the equalization determination SOC is in a state where the number of the unit cells 201 having the equalization determination SOC is equal to or greater than a predetermined threshold can also be adopted.

  In the battery controller 104, when the SOC of the unit cell 201 or the battery module 101 is equalization determination SOC and the current flowing into and out of the battery module 101 is equal to or less than a predetermined value, the voltage of each unit cell 201 constituting the battery module 101 is Determines that it can be regarded as an OCV, and proceeds to the next step in order to start the process of performing the SOC equalization (process 1102).

  The battery controller 104 acquires the voltage of each single cell 201 and converts each voltage into SOC as described above (processing 1103). After that, the lowest SOC is detected and set as the target SOC, and an equalization execution value (discharge time when the switch 303 is turned on) that can reduce the SOC of each unit cell 201 to the lowest SOC is calculated (processing 1104). The SOC equalization control is executed based on the equalization execution value.

  In addition, the count of the SOC stay time for determining the equalization judgment SOC described above is performed by setting up to a predetermined time and an upper limit time, and when the predetermined time has passed, it is cleared and starts counting again. The equalization determination SOC may be determined again. Alternatively, a method of updating the equalization determination SOC by sequentially adding new count information while deleting old count information is also possible. Further, the equalization determination SOC may be obtained and updated during the operation of the battery controller 104. Further, the equalization determination SOC is obtained during the operation of the battery controller 104, and when the battery controller 104 is powered off, the equalization determination SOC is recorded in the memory mounted in the battery controller 104 or in an external memory. A method of reading the recorded equalization determination SOC from the memory and updating the equalization determination SOC at the next activation of the battery controller 104 can also be employed.

  In the equalization determination SOC, the battery controller 104 detects ΔSOC of the unit cells 201 to obtain an equalization execution value (ON time of the switch 303), and executes SOC equalization based on this value. However, if the predetermined time has elapsed since the time when the battery controller 104 has been operated, the SOC equalization has been performed, or if the predetermined time has elapsed since the equalization was completed, the equalization determination SOC is again performed. The ΔSOC of each unit cell 201 may be detected in step 1, and an equalization execution value may be obtained again to execute equalization. Alternatively, it is also possible to employ a method of periodically obtaining the equalization execution value by monitoring the SOC of each unit cell 201 with the equalization determination SOC. In addition, when the state of equalization determination SOC is entered and the current flowing into and out of the battery module 101 falls below a predetermined value, it is possible to detect the ΔSOC of each unit cell 201 and recalculate the equalization execution value each time. It is. A method may be adopted in which a plurality of ΔSOCs in the equalization determination SOC are stored and averaged to extract a statistical ΔSOC characteristic in the equalization determination SOC. In this way, when the battery module 101 is used for a long period of time, it is possible to sequentially cope with the SOC variation newly generated with time, and the SOC that always matches the SOC of each unit cell 201 in the equalization determination SOC. Equalization control can be realized.

  FIG. 12 shows how the SOC changes over time when the battery controller 104 in this embodiment is used. Here, in order to simplify the description, a case where two cells 201a (small full charge capacity) and single battery 201b (large full charge capacity) are connected in series is shown. In FIG. 12, first, the two unit cells 201 stay for a predetermined time (T0-T1) in a low SOC state. It is assumed that the SOCs of the two unit cells 201 are already equalized with the low SOC as the equalization determination SOC. Thereafter, between T1 and T2, the two unit cells 201 connected in series are charged to be in a high SOC state, and the unit cell 201a reaches a higher SOC value than the unit cell 201b due to individual differences in capacity. The case of doing is given as an example.

  The battery controller 104 monitors the SOC transition and detects that the stay at the high SOC is long at the time T3 in the above-described processing. That is, if the longest stay SOC is in a higher SOC range than before, the battery controller 104 equalizes The determination SOC is changed to a high SOC. Then, the lowest SOC in the plurality of unit cells 201 is detected at a high SOC, and the equalization execution value is obtained as described above with this as a target, and the SOC equalization control at the high SOC is started.

  Thus, by extracting the characteristics of the SOC transition as the stay time of the SOC, it is possible to perform the SOC equalization according to how the battery module 101 is used.

  As described above, in this embodiment, the SOC equalization according to the usage method of the battery module 101 is determined by the determination of the equalization determination SOC based on the monitoring result of the SOC transition of the battery module 101 performed by the battery controller 104 and the SOC equalization control. Control can be determined while the battery module 101 is in use. It is possible to determine the equalization determination SOC by adding the longest stay SOC or a correction in consideration of the condition that the influence of deterioration is large to the longest stay SOC, and to equalize the SOC of each unit cell 201 in the vicinity of the equalization determination SOC. . For this reason, it becomes possible to optimally use the battery module 101 composed of a plurality of single cells 201, and it is possible to reduce the occurrence of variation in the deterioration of the single cells 201 during use of the battery module 101. As a result, it is possible to provide a battery control system including the battery controller 104 that can flexibly cope with the characteristics of the unit cell 201 and how the battery module 101 is used.

  In the present embodiment, the process of the battery controller 104 described in the first embodiment is changed. In the present embodiment, when the SOC is high as a characteristic of the unit cell 201, the rate of deterioration is advanced, or there is an opportunity to be charged until the battery module 101 is fully charged. Is described.

  FIG. 13 is an operation flowchart of the battery controller according to the second embodiment of the present invention. First, the battery controller 104 in this embodiment monitors the current flowing into and out of the battery module 101. If the current is less than or equal to a predetermined value, the process proceeds to the next step (process 1301). When the current is less than or equal to a predetermined value, the voltage of each unit cell 201 constituting the battery module 101 can be regarded as an OCV, and the SOC can be easily obtained from the voltage according to the relationship shown in FIG. Subsequently, the battery controller 104 compares the equalization determination SOC when the SOC equalization has been executed previously with the SOC of the unit cell 201 or the battery module 101 at a current equal to or lower than the current predetermined value (processing 1302). As a result, if the SOC of the unit cell 201 or the battery module 101 at the current equal to or lower than the current equalization determination SOC is higher than the previous equalization determination SOC, it is determined that the priority is high, and the unit cell 201 The voltage is converted into SOC (process 1303). Then, the lowest SOC in the plurality of single cells 201 constituting the battery module 101 is detected. Next, an SOC equalization execution value in each unit cell 201 based on the above-described minimum SOC is obtained, and a process of overwriting the equalization execution value determined in the past low value equalization determination SOC is performed (Process 1304). ), SOC equalization is started based on the new equalization execution value.

  If the SOC of the unit cell 201 or the battery module 101 at the current equal to or lower than the current predetermined value is higher than the previous equalization determination SOC, the equalization execution determined by the previous low value equalization determination SOC is performed. Overwrite the value, that is, conversely, if the SOC of the unit cell 201 or the battery module 101 at the time of the current equal to or less than the current predetermined value is lower than the previous equalization determination SOC, the past high value This means that the equalization execution value determined by the equalization determination SOC is left. This reason becomes clear at the end of the description of FIG.

  FIG. 14 shows a change in SOC according to time based on the processing of the battery controller 104 in the present embodiment. Here, in order to simplify the description, a case where two cells 201a (small full charge capacity) and single battery 201b (large full charge capacity) are connected in series is shown. In FIG. 14, first, the two unit cells 201 stay in a low SOC state from time T0 to T1. It is assumed that the SOCs of the two unit cells 201 are already equalized with the low SOC as the equalization determination SOC. Thereafter, between time T1 and T2, the two unit cells 201 connected in series are charged to be in the middle SOC state, and the unit cell 201a has a higher SOC value than the unit cell 201b due to individual differences in capacity. As an example, the case of rising to The battery controller 104 detects that the current is equal to or less than a predetermined value and that the current SOC is higher than the previous equalization determination SOC. Then, this time, it is determined that the priority is high, the voltage of each unit cell 201 is converted to SOC, the equalization execution value of the SOC described above is calculated, and the equalization execution value obtained in the previous equalization determination SOC. Is overwritten. That is, in FIG. 14, the equalization determination SOC is set to the middle SOC, and the SOC equalization is performed (time T2-T3).

  In FIG. 14, charging is performed again between times T3 and T4, and the state of charge changes from medium SOC to high SOC. Similarly, when the battery controller 104 detects that the current is equal to or lower than the predetermined value and the current SOC is higher than the previous equalization determination SOC, the battery controller 104 determines that the priority is high and determines the voltage of each unit cell 201. It converts to SOC, calculates the equalization execution value of the above-mentioned SOC, and overwrites the equalization execution value obtained in the previous (medium SOC) equalization determination SOC. That is, this time, the equalization determination SOC is set to a high SOC, and the SOC equalization is executed (time T4-T5).

  In FIG. 14, at time T5-T6, discharging is performed this time, and the SOC decreases from the high SOC to the middle SOC. The battery controller 104 according to the present embodiment confirms that the current SOC is lower than the previous equalization determination SOC, although the current is equal to or less than the predetermined value. The process of overwriting the equalization execution value of (high SOC) is not executed. Even during the stay period of the middle SOC (time T6-T7), the SOC equalization process is continued based on the previous equalization execution value that eliminates the ΔSOC of each unit cell 201 detected at the high SOC. For this reason, if the SOC of the unit cell 201 or the battery module 101 at the current below the predetermined value is lower than the previous equalization determination SOC described in the description of FIG. The equalization execution value determined by the value equalization determination SOC is left.

  That is, equalization control is performed so as to allow an increase in ΔSOC of each unit cell 201 during the middle SOC period (time T6-T7) so that equalization can be performed when the high SOC range that is the equalization determination SOC is reached. Execute.

  In FIG. 14, charging is performed again in the period of time T7 to T8, and the SOC is increased again from the middle SOC to the high SOC. At this time, since the SOC equalization is continued with the execution value that is equalized when the high SOC is reached even during the stay period of the middle SOC, the two unit cells 201 when the battery is increased to the high SOC range by the current recharging. The SOCs can be matched.

  In the present embodiment, in an application where SOC equalization at high SOC is desired, it is possible to monitor how the battery module 101 is used and perform SOC equalization at high SOC according to the usage.

  In the above description, the equalization execution value is recalculated while updating the equalization determination SOC while the battery controller 104 is operating. However, during the operation of the battery controller 104, when the SOC transition is monitored and the arrival of a higher SOC is detected, this is regarded as the equalization determination SOC, and when the battery controller 104 is turned off, the equalization is performed. The determination SOC may be stored in a memory. Then, when the battery controller 104 is turned on next time, a method of reading the equalization determination SOC from the memory and using it may be employed. In any case, it is possible to provide a battery control system including the battery controller 104 that can flexibly cope with how the battery module 101 is used.

  Next, a third embodiment according to the present invention will be described.

  In the present embodiment, the operation of the battery controller 104 described in the first embodiment or the second embodiment is changed. In the present embodiment, as the characteristics of the unit cell 201, the SOC equalization at a high SOC is the most, for example, when the SOC is high, the speed of deterioration increases, or the battery module 101 has a chance to be fully charged. Describe the desirable case.

  It is assumed that the battery controller 104 in this embodiment sets the equalization determination SOC in advance in the high SOC range. For example, the range is SOC 70-80%, SOC 80-90%. When the battery controller 104 detects that the SOC of the unit cell 201 or the battery module 101 falls within the range of the equalization determination SOC and the current flowing into and out of the battery module 101 is less than or equal to a predetermined value, FIG. By using the relationship, the voltage of the plurality of unit cells 201 is converted into the SOC. As described above, the lowest SOC is detected among the SOCs of the plurality of unit cells 201, ΔSOC is detected for each unit cell 201, and an equalization execution value is obtained for each unit cell 201. By the SOC equalization control using the equalization execution value, the SOCs of the individual cells 201 constituting the battery module 101 can be matched with a high SOC.

  Since the battery controller 104 in the present embodiment is premised on the above-described equalization determination at the high SOC, if the SOC of the unit cell 201 or the battery module 101 does not reach the preset equalization determination SOC, the SOC equalization is indefinite. It is not possible to determine the execution value of the conversion. As a result, there is a possibility that the SOC equalization of each unit cell 201 constituting the battery module 101 cannot be performed. Alternatively, even if the equalization determination SOC is reached, there is a possibility that the SOC equalization cannot be performed indefinitely even when the current flowing into and out of the battery module 101 does not become a predetermined value or less.

  Therefore, the battery controller 104 in the present embodiment has a function of changing the preset equalization determination SOC.

  FIG. 15 is a flowchart for explaining the operation content of the battery controller 104 in the present embodiment for changing the equalization determination SOC, which is a partial function. In this embodiment, first, as described above, the equalization determination SOC is set in advance in the high SOC range (processing 1501). If the SOC of the unit cell 201 or the battery module 101 is in the preset high SOC range equalization determination SOC and the current flowing into and out of the battery module 101 is equal to or less than the predetermined value, the equalization is performed as described above. An execution value is obtained, and based on this, SOC equalization based on high SOC is performed. This is executed by the same processing flow as in FIG.

  However, when the SOC of the unit cell 201 or the battery module 101 does not enter the equalization determination SOC, or when the current flowing into and out of the battery module 101 does not fall below a predetermined value even after entering the equalization determination SOC (processing 1502), etc. If the equalization execution value cannot be obtained for a predetermined time or longer (process 1503), the battery controller 104 changes the preset equalization determination SOC range to a lower value (process 1504).

  As a method of changing the equalization determination SOC range to a low value, the upper and lower limit SOCs of the equalization determination SOC range are lowered by 10%, the processing is performed from the processing 1502 of FIG. There is a method of monitoring again. When a state where the execution value of the SOC equalization cannot be obtained again for a predetermined time or more again occurs, the equalization determination SOC range is lowered by 10% again.

  In the above description, the equalization determination SOC range is decreased by 10%. However, the SOC decrease amount when changing the equalization determination SOC range, such as 1% or 5%, can be arbitrarily set. Alternatively, as described in the first embodiment, it is also possible to count the staying time of the SOC and determine the equalization determination SOC range based on this. Further, as shown in FIG. 16, it is possible to realize the SOC equalization of the battery module 101 by a method of arbitrarily lowering only the lower limit SOC in the equalization determination SOC range by the method described above.

  In FIG. 15, when the current is equal to or lower than the predetermined value (process 1502) but higher than the equalization determination SOC (process 1505), the battery controller 104 determines that the preset equalization determination SOC is set. The range is changed to, for example, a value 10% higher (process 1506). After that, when the SOC is higher than the equalization determination SOC again (judgment by the same route) (process 1505), the equalization determination SOC range is again changed to a value 10% higher (process 1506). The method of changing the equalization determination SOC to a high value can be executed following the method of changing the equalization determination SOC to a low value as described above. Alternatively, a method may be used in which it is determined that the above-described high SOC opportunity can come again, and the equalization determination SOC range is rapidly increased until the high SOC described above is included. Furthermore, as shown in FIG. 13, it is possible to adopt a method in which it is determined that the SOC is higher than in the previous equalization determination, and the equalization execution value is overwritten.

  The effect of the SOC equalization based on the process of the battery controller 104 in the present embodiment will be described with reference to FIG. Here, in order to simplify the description, a case where two cells 201a (small full charge capacity) and single battery 201b (large full charge capacity) are connected in series is shown. In the battery controller 104 of this embodiment, the equalization determination SOC range is set to a high range in advance, and the SOCs of the two unit cells 201 are equalized in the high SOC range, and the two unit cells 201 are at the time T0. -Stays at high SOC for T1.

  Between time points T1 and T2, the battery module 101 is discharged and the SOC decreases, and the stay in the low SOC after time point T2 has passed a predetermined time or more at time point T3, that is, an execution value of SOC equalization is obtained. When it is detected that a predetermined time or more has passed, the battery controller 104 changes the upper limit SOC and lower limit SOC of the equalization determination SOC or only the lower limit SOC to a lower value within the above-described arbitrary range. Alternatively, as described in the first embodiment, the equalization determination SOC is reset by using the count value of the SOC stay time. Thereby, even when the usage of the battery module 101 becomes unexpected, it is possible to perform the SOC equalization.

  In FIG. 17, the case where the SOC of the unit cell 201 or the battery module 101 does not fall within the preset equalization determination SOC range is described as an example. However, as described above, the SOC of the unit cell 201 or the battery module 101 is equalization determination. Even if the SOC is in the SOC range but the current flowing into and out of the battery module 101 does not fall below the predetermined value and the SOC equalization cannot be performed, the battery module 101 is configured by changing the above-described equalization determination SOC range. SOC equalization of each unit cell 201 to be performed is performed.

  In the present embodiment, the equalization determination SOC range can be flexibly changed even when the equalization determination SOC range set in advance does not provide an opportunity for SOC equalization.

  In the above description, the equalization determination SOC range is set high in advance, and when equalization cannot be performed, the equalization determination SOC range is changed to a low value. However, an operation opposite to this can be adopted. That is, the equalization determination SOC range is set low in advance, and if equalization cannot be performed, the equalization determination SOC range is changed to a higher value.

  By using the battery controller 104 in the present embodiment, the preset equalization determination SOC range can be changed according to how the battery module 101 is used. In the above description, the equalization determination SOC is updated while the battery controller 104 is operating. However, the obtained equalization determination SOC is stored in the memory when the battery controller 104 is turned off, and the battery controller 104 When the power source 104 is turned on, a method in which the obtained equalization determination SOC is read from the memory and used can also be employed.

  By applying the battery controller 104 of the present embodiment, a battery control system that can flexibly perform SOC equalization according to how the battery module 101 is used can be realized.

  In this embodiment, the case where the battery system of FIG. 1 of the present invention is used as a power source for stabilizing wind power generation or solar power generation will be described. In wind power generation or solar power generation, insufficient power is covered by energy stored in the battery system, and surplus power is stored in the battery system, and the battery system stabilizes power from wind power generation or solar power generation.

  FIG. 18 shows an image of processing contents in the present embodiment.

  The battery controller 104 of the present embodiment detects the long-term stay SOC described in the first embodiment on a monthly basis, for example.

  FIG. 18A is an image of the SOC transition of the battery module 101 for one year. There are strong and weak winds depending on the season. In addition, the outside temperature and sunshine vary depending on the weather and season. For this reason, when a battery system is used as a stabilizing power source in wind power generation or solar power generation, the SOC transition of the battery system may change depending on the season.

  In the battery controller 104, assuming that the operation start of the battery system is X years, initial equalization determination SOCs are set as X1 to X12 in units of months as initial values. As the initial values X1 to X12, for example, an SOC range in which there is almost no problem even if the SOC is equalized for every application, such as ± 5% centering on SOC 50%, is selected. Alternatively, when past data exists at a place where wind power generation or solar power generation is installed, a method of setting X1 to X12 based on the past data can also be employed. When operation of the battery system is started as a stabilized power source, the long-term stay SOC is detected on a monthly basis as shown in FIG. 9 of the first embodiment. Alternatively, the SOC range that is maximized is obtained by multiplying the SOC stay time for each SOC range divided by a predetermined step size by the deterioration parameter. When the battery controller 104 obtains the SOC range obtained by multiplying the deterioration parameter by the long-term stay SOC or the SOC stay time in each month, the data of all months is collected at any time at the end of the month or at the end of the year. Overwrite to.

  The processing contents of the battery controller 104 in the next year Y will be described. In the Y year, the battery controller 104 performs SOC equalization control on a monthly basis according to the SOC range that is maximized by multiplying the deterioration time by the long-term stay SOC per month or the SOC stay time per SOC range in the year X. I do. Thereby, SOC equalization can be implemented optimally every month. Furthermore, as in year X, in year Y, the longest staying SOC or SOC staying time for each SOC range is multiplied by the deterioration parameter to detect the largest SOC range every month, and these are stored as Y1 to Y12. To do. In the following year Z, the SOC range that becomes the largest by multiplying the degradation parameter by the long-term stay SOC in year Y or the SOC stay time for each SOC range, which is last year, is used as the monthly equalization determination SOC. Alternatively, the average value of the SOC range that has become the largest by multiplying the deterioration parameter by the SOC stay time for each long-term stay SOC in each of the X and Y years or the SOC range is obtained every month, and this is determined as the equalization judgment SOC for each month. And Using the average value of year X and year Y can absorb individual differences in units of years and realize stable SOC equalization. Furthermore, since the number of samples in the SOC range that has become the largest by multiplying the deterioration parameter by the SOC stay time for each long-term stay SOC or each SOC range increases with age, more stable SOC equalization can be realized.

  As described above, when using a battery system for stabilizing wind power generation or solar power generation, the optimal SOC equalization according to the time is realized even for applications where the SOC transition changes depending on the season can do.

  The battery controller 104 of the present embodiment includes a startup circuit (not shown) that periodically starts itself even when the battery system is stopped. In the embodiments so far, the SOC transition during operation of the battery system is monitored, but in this embodiment, the focus is on a case where the period is longer than that during operation of the battery system.

  In this embodiment, the battery controller 104 is periodically activated while the battery system is stopped, and detects the SOC of the unit cell 201 or the battery module 101. Then, as shown in FIG. 9 of the first embodiment, the SOC stay time for each SOC range while the battery system is stopped is measured, and the longest stay SOC or the SOC stay time for each SOC range is multiplied by the deterioration parameter to be the largest. The SOC range is detected. When the battery system is stopped or the battery system is operating, the battery controller 104 multiplies the detected longest stay SOC or SOC stay time for each SOC range while the battery system is stopped by multiplying the deterioration parameter and becomes the largest. In the SOC range, the SOC variation of the unit cells 201 constituting the battery module 101 is detected. Then, the above-described SOC equalization is executed based on the detected SOC variation. For applications with a long battery system outage period, if the SOC equalization is achieved in the SOC range that is maximized by multiplying the SOC stay time for each longest stay SOC or SOC range during the battery system outage by the deterioration parameter, The occurrence of individual differences due to the influence of storage deterioration of the unit cells 201 constituting the battery module 101 can be reduced.

  In the first to fifth embodiments, the SOC equalization that matches the lowest SOC among the single cells 201 constituting the battery module 101 is taken as an example. However, the present invention is not limited to this. It is also possible to perform equalization processing based on the voltage value without matching to the average SOC or the intermediate SOC between the highest SOC and the lowest SOC among the SOCs of the individual cells 201.

  Further, in the first to fifth embodiments, the resistor 301 and the switch 303 are used to reduce the SOC by consuming the energy of the unit cell 201 having a high SOC, thereby realizing the SOC equalization. The present invention is not limited to this, and SOC equalization may be realized by transferring the energy of the unit cell 201 having a high SOC to the unit cell 201 having a low SOC.

  The SOC equalization method of the present invention can flexibly cope with how the battery module 101 is used. The present invention can be widely applied to power storage systems including power storage devices that can store and discharge electricity. When the battery module 101 is used for a long time, each of the components constituting the battery module 101 is performed by performing one or more of the SOC equalization methods of the above-described embodiments and periodically performing a predetermined time each time. The SOC of the unit cells 201 can be continuously distributed in a predetermined range.

  In addition, it is also possible to combine each embodiment described above and one or a plurality of modifications. Any combination of the modified examples is possible.

  The above description is merely an example, and the present invention is not limited to the configuration of the above embodiment.

  DESCRIPTION OF SYMBOLS 101 ... Battery module, 102 ... Current detection means, 103 ... Voltage detection means, 104 ... Battery controller, 105 ... Switch means, 106 ... Battery system controller, 201 ... Single cell, 202 ... Module control circuit, 301 ... Resistance, 302 ... Integrated circuit 303 ... Switch 304 ... Voltage detection circuit 305 ... Control circuit 306 ... Signal input / output circuit 401 ... Electromotive force 402 ... Internal resistance 403 ... Impedance 404 ... Capacitance component

Claims (15)

A voltage detection circuit for detecting the voltage of each of the cells connected in series;
An SOC adjustment circuit for adjusting the SOC of each unit cell in a direction to equalize the remaining capacity (SOC) of each unit cell;
In a battery control system comprising a control circuit that detects an SOC variation based on each voltage of the single cells detected by the voltage detection circuit and transmits an adjustment command to the SOC adjustment circuit.
The control circuit includes:
Discretizing the SOC at a predetermined step size;
From the discretized SOC range, an SOC range having a high probability of staying in the SOC of the single battery or the multi-series battery is detected,
When the SOC of the single battery or the multi-series battery is within the SOC range where the stay probability is high, the adjustment command for equalizing each SOC of the single battery is within the SOC range where the stay probability is high or outside the range. A battery control system for transmitting to an SOC adjustment circuit. A voltage detection circuit for detecting the voltage of each of the cells connected in series;
An SOC adjustment circuit capable of adjusting the SOC for each unit cell so that the SOC of each unit cell is substantially equal;
In a battery control system comprising a control circuit that detects the SOC variation degree based on each voltage of the single cells detected by the voltage detection circuit and transmits an adjustment command to the SOC adjustment circuit from the SOC variation degree.
The control circuit includes:
Discretizing the SOC at a predetermined step size;
For each of the discretized SOC ranges, calculate a probability distribution that the SOC stays,
From the probability distribution, an SOC range where the stay probability of the SOC of the single battery or the multi-series battery is high is detected,
When the SOC of the unit cell or the multi-series cell is within the SOC range where the stay probability is high, an adjustment command for equalizing each SOC of the unit cell is within the SOC range where the stay probability is high or outside the range. A battery control system for transmitting to the SOC adjustment circuit.   The control circuit according to claim 1 or 2, wherein the SOC of the single battery or the multi-series battery is within an SOC range where the stay probability is high and the current flowing into and out of the multi-series battery is equal to or less than a predetermined value. A battery control system that detects SOC variation based on each voltage of a single cell.   The control circuit according to any one of claims 1 to 3, wherein the control circuit combines the probability distribution calculated by the discretized SOC and a parameter prepared for each discretized SOC, and the probability distribution of the discretized SOC. A battery control system, wherein an SOC range in which the SOC of the unit cells is to be equalized is determined based on the parameter.   5. The battery control system according to claim 4, wherein the parameter is a deterioration parameter determined based on a storage test or a cycle test of a single battery or a multi-series battery.   6. The predetermined step size for discretizing the SOC according to any one of claims 1 to 5 includes the life of the unit cell, the SOC variation of the individual difference of the full charge capacity generated as the SOC changes, and the degree of SOC variation allowed by the system Or a battery control system, wherein the battery control system is determined by an SOC error generated from a measurement error of the voltage detection circuit.   7. The control circuit according to claim 1, wherein the control circuit stores the SOC range having a high stay probability when the control circuit is powered off, and the recording circuit is restarted when the control circuit is restarted. A battery control system characterized by reading from the battery. In any one of Claims 1-7,
In the control circuit, the SOC of the single battery or the multi-series battery is outside the current SOC adjustment range, and the time when the SOC of the single battery or the multi-series battery stays in the current SOC adjustment range (T0-T1 in FIG. 12). ) And stays in another SOC range (T2-T3), the SOC adjustment range is changed from the current SOC adjustment range (low SOC in FIG. 12) to the other SOC range (high SOC in FIG. 12). The battery control system is characterized by being changed to In any one of Claims 1-8,
When the current SOC of the single cell or the multi-series battery is outside the SOC adjustment range, the control circuit gives a difference (variation) in the SOC between the single cells, and when the high residence probability SOC is subsequently entered, A battery control system that performs equalization control so as to equalize SOC between batteries. In any one of Claims 1-9,
The control circuit is set so that the current SOC adjustment range is set high, and the SOC of the single battery or the multi-series battery stays outside the current SOC adjustment range for a predetermined time (T2-T3 in FIG. 17). ), And changing the SOC adjustment range to a low value. In claim 10,
The control circuit changes the SOC adjustment range to a high value when the current flowing into and out of the multi-series battery is below a predetermined value and the SOC of the single battery or the multi-series battery is higher than the SOC adjustment range. A battery control system characterized by. In claim 1,
The control circuit detects an SOC variation degree from each voltage of the unit cell to determine an SOC adjustment range for transmitting an adjustment command to the SOC adjustment circuit, and the determined SOC adjustment range is a power supply of the control circuit Is recorded in the storage means, and when the control circuit is restarted, the recorded SOC adjustment range is read, and each SOC of the unit cells is equalized based on the read SOC adjustment range A battery control system for transmitting an adjustment command to the SOC adjustment circuit.   3. The control circuit according to claim 1, wherein the control circuit divides time by a predetermined step size, calculates a probability distribution of the SOC of the single cell or the multi-series battery at each time divided by the step size, and the step size. The SOC range having a high stay probability at each time divided by the step size is detected from the probability distribution obtained at each time divided by the step size, and the step size that most closely matches the current use conditions of the multi-series battery An adjustment command for equalizing each SOC of the unit cell when the SOC of the unit cell or the multi-series cell is within the SOC range where the stay probability obtained at the selected time is within a high SOC range, A battery control system for transmitting to the SOC adjustment circuit.   3. The control circuit according to claim 1, wherein the control circuit includes an activation circuit that activates itself at a predetermined interval while the operation of the battery control system is stopped, and the operation of the battery control system is stopped. The SOC of the single battery or the multi-series battery is discretized at a predetermined step size, the probability distribution is calculated based on the discretized SOC, and the SOC range where the stay probability of the SOC of the single battery or the multi-series battery is high from the probability distribution. A battery control system characterized by detecting. A voltage detection step of detecting the voltage of each of the cells connected in series;
An SOC adjustment step of adjusting the SOC of each unit cell in a direction to equalize the remaining capacity (SOC) of each unit cell;
In a control method of a battery control system comprising a control step of detecting an SOC variation based on each voltage of the single cells detected in the voltage detection step and transmitting an activation command for the SOC adjustment step.
A discretization step for discretizing the SOC at a predetermined step size;
A high stay probability SOC range detecting step for detecting an SOC range having a high SOC stay probability of a single battery or a multi-series battery from the discretized SOC range;
When the SOC of the single battery or the multi-series battery is within the high stay probability SOC range, an adjustment command for equalizing each SOC of the single battery is performed within the high stay probability SOC range or out of the range. A control method for a battery control system, comprising a step of transmitting a step start command.

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