JP5977979B2 - Electric storage device for railway vehicles - Google Patents

Description

  The present specification relates to a power storage device for a railway vehicle that can travel with electric power of a power storage device mounted on a vehicle, and more particularly to a technique for detecting a full charge capacity of the power storage device.

  In recent years, with the spread of hybrid vehicles and electric vehicles, the performance of power storage devices has been remarkably improved, and railway vehicles capable of running on the power of the installed power storage devices such as storage battery trains have been developed. In such a railway vehicle, it is necessary to detect the full charge capacity of the railway vehicle power storage device, for example, by periodic inspection, and to grasp the degree of deterioration and the replacement time of the power storage device from the detection result.

  Here, conventionally, there is a battery capacity detection device that detects a full charge capacity of a power storage device (Patent Document 1). In this battery capacity detection device, the charging characteristics relating to the charging time from the intermediate discharging state to the fully charged state are stored in advance in the charging characteristic storage unit. Actually, the battery is charged from the predetermined intermediate discharge state to the full charge state, the charge time required for the charge is measured, and the full charge capacity of the battery is detected based on the charge time and the charge characteristics. The

JP 2005-265801 A

  However, in the conventional battery capacity detection device, there is a problem that it is indispensable to put the battery in a fully charged state in order to detect the full charge capacity, and there is a technique for detecting the full charge capacity by other means. It was requested.

  In this specification, a technique capable of detecting the full charge capacity of the power storage device by means different from the conventional technique is disclosed.

  The power storage device for a railway vehicle that travels with the power of the power storage element disclosed by the present specification includes the power storage element, a voltage measurement unit that measures a terminal voltage of the power storage element, and the OCV and SOC of the power storage element. A memory for storing information related to the correlation, a charging unit that charges the power storage element with electric power from an external power source, and a control unit, the control unit based on the measurement result of the voltage measurement unit The first OCV of the storage element is specified, and in the correlation, after the first SOC specifying process for specifying the first SOC corresponding to the first OCV and the first SOC specifying process, the charging unit causes the storage element to have a constant current. The amount-of-electricity change process for charging for a predetermined time at the time, and after the amount-of-electricity change process, the second OCV of the electricity storage element is specified based on the measurement result of the voltage measurement unit, and the correlation Then, based on the second SOC specifying process that specifies the second SOC corresponding to the second OCV, the SOC change amount that is the difference between the first SOC and the second SOC, and the amount of electricity charged in the electricity amount changing process. And a capacity detection process for detecting a full charge capacity of the power storage element.

  There is a correlation between the SOC change amount before and after the electric quantity change processing and the full charge capacity of the power storage element. Further, the first SOC and the second OCV can be specified based on the first OCV and the second OCV, and information related to the correlation between the OCV and the SOC. Therefore, according to the railway vehicle power storage device, the full charge capacity of the power storage element can be detected based on the SOC change amount and the amount of electricity charged by the amount-of-electricity change process. In addition, since the electric current is constant in the electric quantity changing process, it is possible to suppress a decrease in the detection accuracy of the full charge capacity due to an integration error or the like as compared with the configuration in which the electric current is not constant and the electric quantity is integrated.

  In the power storage device for a railway vehicle, the railway vehicle travels in an overhead line section connected to an overhead line and a non-overhead line section not connected to the overhead line, and the control unit changes the electric quantity in the overhead line section. In the processing, the charging unit may be configured to charge the power storage element with electric power supplied from the overhead wire electrically connected to the charging unit. Thereby, charging and each processing can be performed anywhere in the section with the overhead line.

  In addition, the power storage device for a railway vehicle that travels with the power of the power storage element has information on a correlation between the power storage element, a voltage measuring unit that measures a terminal voltage of the power storage element, and OCV and SOC of the power storage element. A memory to be stored; a discharge unit that discharges the electric power of the power storage element to the outside; and a control unit, wherein the control unit specifies a first OCV of the power storage element based on a measurement result of the voltage measurement unit. In the correlation, after the first SOC specifying process for specifying the first SOC corresponding to the first OCV and the first SOC specifying process, the discharge unit discharges the power storage element with a constant current for a fixed time after the first SOC specifying process. After the change process and the electric quantity change process, the second OCV of the power storage element is specified based on the measurement result of the voltage measurement unit, and corresponds to the second OCV in the correlation. A capacity for detecting the full charge capacity of the power storage element based on the second SOC specifying process for specifying 2SOC, the SOC change amount that is the difference between the first SOC and the second SOC, and the amount of electricity discharged in the discharge process You may have the structure which performs a detection process.

  There is a correlation between the SOC change amount before and after the electric quantity change processing and the full charge capacity of the power storage element. Further, the first SOC and the second OCV can be specified based on the first OCV and the second OCV, and information related to the correlation between the OCV and the SOC. Therefore, according to this railway vehicle power storage device, it is possible to detect the full charge capacity of the power storage element based on the SOC change amount and the amount of electricity discharged in the amount-of-electricity changing process. In addition, since the electric current is constant in the electric quantity changing process, it is possible to suppress a decrease in the detection accuracy of the full charge capacity due to an integration error or the like as compared with the configuration in which the electric current is not constant and the electric quantity is integrated.

  In the railway vehicle power storage device, in the electric quantity change process, the control unit supplies power discharged from the power storage element by the discharge unit to an overhead wire electrically connected to the discharge unit. May be.

  In the railway vehicle power storage device, in the second SOC specifying process, the control unit is configured to perform the non-convergence period when the terminal voltage of the power storage element has not converged to OCV after the electric quantity change process. The second OCV may be specified based on the measurement result of the voltage measurement unit.

  According to the power storage device for a railway vehicle, the second OCV is specified based on the measurement result of the voltage measurement unit when the non-convergence period elapses before the terminal voltage of the power storage element converges to the OCV after the electric quantity change process. Is done. Since the current is constant in the electric quantity changing process, the terminal voltage when the non-convergence period elapses and the OCV after the convergence period elapses are substantially correlated. For this reason, it is possible to detect the full charge capacity within the non-convergence period while suppressing variation in the specific accuracy of the second OCV as compared with the configuration in which the current is not constant and the amount of electricity is integrated.

  In the railway vehicle power storage device, the memory stores a polarization voltage value of the power storage element when the non-convergence period has elapsed, and the control unit determines the terminal voltage of the measurement result in the second SOC specifying process. The second OCV may be specified based on the value and the partial pressure electrode value.

  According to this railway vehicle power storage device, the second OCV is specified based on the terminal voltage value of the measurement result when the non-convergence period has elapsed and the divided electrode value measured in advance. Thereby, compared with the structure which specifies 2nd OCV, without considering a partial pressure electrode value, 2nd OCV can be detected with a sufficient precision.

  The railway vehicle power storage device includes a temperature measurement unit that measures the temperature of the power storage element, the memory stores information indicating a correspondence relationship between the temperature and the polarization voltage value, and the control unit In the second SOC specifying process, the polarization voltage value corresponding to the measurement result of the temperature measurement unit may be derived with reference to information indicating the correspondence relationship.

  According to the railway vehicle power storage device, the polarization voltage value corresponding to the measurement result of the temperature measurement unit is derived with reference to the information indicating the correspondence relationship between the temperature of the power storage element and the polarization voltage value. The second OCV is identified using the polarization voltage value. Thereby, even if the polarization voltage value fluctuates due to the temperature change of the power storage element, it is possible to suppress the specific accuracy of the second OCV from being lowered due to the fluctuation.

  In the railway vehicle power storage device, it is preferable that the correlation between the OCV and the SOC is not changed regardless of deterioration of the power storage element.

  According to the invention disclosed in this specification, it is possible to detect the full charge capacity of the power storage device by means different from the prior art.

Overall configuration diagram of a storage battery-driven train system according to Embodiment 1 Graph showing correlation between OCV and SOC Graph showing voltage return characteristics Flow chart showing deterioration determination processing Graph showing the relationship between capacity ratio and elapsed time The flowchart which shows the degradation determination processing of Embodiment 2.

<Embodiment 1>
The storage battery drive train system 1 of Embodiment 1 will be described with reference to FIGS.

(Configuration of battery-powered train system)
As shown in FIG. 1, the storage battery-driven train system 1 includes a railway vehicle 10 that can travel in a non-electrified section (an example of a non-overhead section) only with the power of the storage battery 15, and the ground for charging the storage battery 15 in a short time. A charging facility 30 is provided. As long as the railway vehicle 10 can be driven by the power of the storage battery, for example, any of a liquid diesel vehicle, a diesel / electric storage hybrid vehicle, an overhead wire-less electric vehicle, an overhead wire / ground storage hybrid, an overhead wire / on-vehicle storage hybrid, etc. But you can.

  The railway vehicle 10 includes a motor 11, an inverter 12, a power conversion device 13, a power storage system 14, and an auxiliary power supply device 19. The motor 11 is an induction motor that drives the railway vehicle 10 by applying power to a wheel axle (not shown), and the output is, for example, 95 kW. The inverter 12 includes, for example, an inverter of a VVVF system (variable voltage variable frequency control system) whose input voltage is 600 V DC and controls the rotation of the motor 11. The power conversion device 13 is an example of a charging unit, has a DCDC converter, and can bidirectionally convert the direct current 1500V of the overhead line 40 and the direct current 600V for the storage battery. The power converter 13 is electrically connected to the overhead line 40 via the pantograph 41.

  The power storage system 14 is an example of a power storage device for a railway vehicle, and includes a storage battery 15 and a battery management device 16. The storage battery 15 is specifically a lithium ion battery. Here, various types of lithium ion batteries are applicable as the present embodiment. For example, as a positive electrode active material, lithium manganate, lithium cobaltate, composite lithium nickelate (a part of nickel is manganese) , Substituted with a transition metal such as cobalt) or a mixture thereof, and a material using a carbon material as a negative electrode active material.

  In particular, it is preferably applied in the case of a lithium ion battery in which a single component active material is used as each electrode active material, and more preferably, lithium manganate as the positive electrode active material and amorphous type as the negative electrode active material. The present invention is preferably applied to a lithium ion battery using a carbon material. The reason is that there is little change in the correlation between OCV and SOC due to battery use. Of course, a battery in which the correlation between OCV and SOC changes may be used. This is because even with such a battery, the detection accuracy is somewhat lowered, but the full charge capacity can be detected in an approximate range. In the following description, it is assumed that the battery cell 15A constituting the storage battery 15 has a rated capacity of 30 Ah, lithium manganate is used for the positive electrode, and an amorphous carbon material is used for the negative electrode. The battery cell 15A is an example of a power storage element.

  The storage battery 15 includes a plurality of battery modules 17 connected in series. Each battery module 17 includes a battery cell group 17A in which a plurality of battery cells 15A are connected in series, a battery monitoring board 17B, and a temperature sensor 17C. Each battery cell group 17 </ b> A is connected in series via a breaker 18 between a pair of outputs of the power converter 13. Each temperature sensor 17C is a thermistor, for example, and outputs a signal corresponding to the ambient temperature of the corresponding battery cell group 17A. Each battery monitoring board 17B measures the voltage of each cell unit (hereinafter simply referred to as cell voltage) corresponding to the battery monitoring board 17B, and outputs the voltage measurement signal corresponding to the measurement result and the signal output from each temperature sensor 17C to the temperature. The converted temperature measurement signal can be transmitted to the battery management device 16. The battery monitoring board 17B is an example of a voltage measurement unit, and the temperature sensor 17C is an example of a temperature measurement unit.

  Hereinafter, a configuration in which the full charge capacity is detected for each battery cell 15 </ b> A constituting the storage battery 15 and the minimum full charge capacity is determined to be deteriorated as the full charge capacity of the storage battery 15 will be described as an example. This is because the capacity that can be discharged is limited to the minimum full charge capacity. Of course, when the characteristic variation between the battery cells 15A is small to some extent, the configuration for determining the deterioration by directly detecting the full charge capacity based on the voltage of the entire storage battery 15, the average value of the full charge capacity of each battery cell 15A, etc. Alternatively, the deterioration determination may be made as the full charge capacity of the storage battery 15.

  The battery management device 16 is an example of a control unit, and includes a CPU 16A (central processing unit) and a memory 16B. The memory 16B has, for example, RAM and ROM, and stores various programs (including a deterioration determination program) for controlling the operation of the battery management device 16, and the CPU 16A follows the program read from the memory 16B. Each part is controlled, for example, a deterioration determination process described later is executed. Further, the CPU 16A can calculate the voltage of the entire storage battery 15 based on the voltage measurement signal from the battery monitoring board 17B, and can calculate the voltage of the entire storage battery 15 based on the temperature measurement signal. The temperature can be measured.

  The memory 16B stores OCV-SOC related data when the battery cell 15A of the storage battery 15 is in the charged state. As shown in FIG. 2, the OCV-SOC relation data is information indicating a correlation between OCV (open circuit voltage voltage) and SOC (remaining capacity state of charge) for the battery cell 15A. It can be obtained in advance by experiments or specifications for the battery cell 15A. The OCV-SOC relationship data may be a correspondence table between OCV and SOC, or function data.

  Also, FIG. 3 shows a case where the storage battery 15 is charged for a fixed time with a constant current, then the charging is stopped, and the battery cell 15A of the storage battery 15 is left in an open state (no load state) where no current flows. The change of the cell voltage, so-called voltage return characteristic is shown. In the figure, the value of the constant current is indicated by I, and is preferably 100 A or more when the traveling of the railway vehicle 10 is stopped, and is 180 A in this embodiment, for example. In the present embodiment, a Hall sensor with a rated current of 300 A is used for constant current charging / discharging and current measurement. To improve accuracy, a current that is 30% or more of the rated current value of the current sensor as described above. Preferably, a current of 50% or more is used. Further, the fixed time is indicated by T0, for example, 180 seconds. Therefore, the amount of electricity to be charged (= I × T0) is 9 Ah, which is preferably about 30% of the rated capacity of the battery cell 15A. The cell voltage of the battery cell 15A drops by a voltage ΔVR corresponding to the internal resistance of the storage battery 15 when charging is stopped, and then converges to the open circuit voltage VE. Hereinafter, the time from when charging is stopped until convergence to the open circuit voltage VE is referred to as a convergence period TE. This convergence period TE is, for example, 5 or 6 hours.

  Here, the difference ΔVM between the cell voltage VM and the open-circuit voltage VE when the non-convergence period TM (<convergence period TE) has elapsed since the charge was stopped indicates the polarization voltage value of the battery cell 15A storage battery 15 at that time. . Therefore, the polarization voltage value ΔVM measured in advance is stored in the memory 16B. Since this polarization voltage value ΔVM varies depending on the temperature of the battery cell 15A, the memory 16B stores the polarization voltage value ΔVM in association with each of a plurality of set temperatures that differ by, for example, 5 degrees. Note that the non-convergence period TM is, for example, 900 seconds.

  The ground charging facility 30 includes a transformer 31, a rectifier 32, a power conversion device 33, and a storage battery 34. The transformer 31 and the rectifier 32 convert electric power from a distribution line (not shown) from AC 6600 V to DC 1500 V, and supply the overhead line 40 and the power converter 33. The power conversion device 33 has a DCDC converter and can bidirectionally convert the direct current 1500V of the overhead line 40 and the direct current 600V for the storage battery. The storage battery 34 is charged with power supplied from the power conversion device 33.

  With the above configuration, in the electrified section (an example of the overhead line section), the railway vehicle 10 supplies the power supplied from the overhead line 40 via the pantograph 41 to the inverter 12 as traveling power while being stepped down by the power converter 13. It is done. Further, when the SOC of the storage battery 15 is low, a part of the power from the overhead line 40 is used for charging the storage battery 15. In addition, the regenerative power during braking is prioritized for charging the storage battery 15, but is used for regenerating the overhead wire 40 when the SOC is high.

  On the other hand, in the non-electrified section, the railway vehicle 10 stops the power conversion device 13, whereby only the power from the storage battery 15 is given to the inverter 12 as traveling power. The regenerative power during braking is used not only for charging the storage battery 15 but also for charging the auxiliary power supply device 19.

  When charging the storage battery 15, as shown in FIG. 1, the railway vehicle 10 stops at a station where the ground charging facility 30 is installed, for example, and raises the pantograph 41, so that the ground charging facility is connected via the overhead line 40. 30, and the battery 15 is rapidly charged.

(Deterioration judgment process)
As illustrated in FIG. 1, the battery management device 16 executes the deterioration determination process illustrated in FIG. 4 for the storage battery 15 in a state where the railway vehicle 10 is electrically connected to the ground charging facility 30. Specifically, the CPU 16A controls the power conversion device 13 to perform an initial discharge process for discharging the storage battery 15 until the SOC reaches the initial value X0. Specifically, the CPU 16A discharges the storage battery 15 (S1). For example, among the cell voltages of the plurality of battery cells 15A constituting the storage battery 15, the minimum cell voltage value is the initial value X0 in the OCV-SOC related data. It is determined whether or not the value is equal to the open circuit voltage corresponding to (S2). The initial value X0 is preferably set within a range of 20% ± 10%. In this initial discharge process, the electric power discharged from the storage battery 15 is supplied to the overhead wire 40 or the auxiliary power supply device 19.

  If the CPU 16A determines that the minimum cell voltage is not the same as the open circuit voltage corresponding to the initial value X0 (S2: NO), the CPU 16A continues the discharge, and if it is the same (S2: YES), stops the discharge. (S3). Then, for example, the CPU 16A opens the breaker 18 to open the storage battery 15 and leaves it for a predetermined waiting time (S4). The waiting time is equal to or longer than the convergence period TE, and is, for example, 5 or 6 hours, preferably 12 hours or longer. Thereby, even when it is unclear whether the state of the storage battery 15 before the initial discharge is the charged state or the discharged state, the storage battery 15 can be brought into an equilibrium state to accurately measure the open voltage of each battery cell 15A. It becomes possible.

  CPU 16A executes the first SOC specifying process for each battery cell 15A (S5). Specifically, the CPU 16A measures the cell voltage of the battery cell 15A of the storage battery 15 in the above-described equilibrium state, refers to the OCV-SOC relation data, and the first SOC corresponding to the measured value V1 of the cell voltage. The value X1 is specified (see FIG. 2). Next, the CPU 16A controls the power conversion device 13 with the breaker 18 closed, and performs electric current change processing for executing constant current charging at the current value I described above for a predetermined time T0 with the electric power from the ground charging facility 30. Is executed (S6). After that, the CPU 16A opens the breaker 18 and leaves the storage battery 15 in the open state to leave it for the non-convergence period TM (S7), and when the non-convergence period TM has elapsed, the cell voltage of the battery cell 15A of the storage battery 15 and The temperature is measured (S8).

For each battery cell 15A, the CPU 16A extracts the polarization voltage value ΔVM corresponding to the measured temperature from the memory 16B, and from the measured value V of the cell voltage and the polarization voltage value ΔVM, the OCV value V2 (V21, V22 = V−ΔVM) is calculated (S9). Thereby, the OCV of each battery cell 15A can be specified without waiting for the convergence period TE. Then, the CPU 16A identifies the second SOC value X2 (X21, X22) corresponding to the cell voltage value V2 with reference to the OCV-SOC relation data for each battery cell 15A (see FIG. 2 in S10). This process is an example of a second SOC specifying process.

  Here, as shown in FIG. 2, when a new storage battery 15 is charged by the amount of electricity from a state where the SOC is X1, the open circuit voltage reaches V21, and the SOC reaches X21. On the other hand, when the deteriorated storage battery 15 is charged by the amount of electricity from the state where the SOC is X1, the open circuit voltage exceeds V21 and reaches V22, and the SOC exceeds X21 and reaches X22. In short, the SOC change amount ΔX (= X2−X1), which is the difference between the first SOC and the second SOC, and the full charge capacity of the storage battery 15 have a correlation and can be expressed by the following expression.

SOC change amount ΔX = (amount of electricity charged in S6 (I × T0) / full charge capacity) × 100
However, the amount of electricity charged in S6 is a fixed value.

  Therefore, if the SOC change amount ΔX can be calculated, the full charge capacity can be specified from the equation. The correlation between the OCV and the SOC of each battery cell 15A of the storage battery 15 described above hardly changes regardless of the degree of deterioration of the storage battery 15. That is, common OCV-SOC relationship data can be used to calculate the SOC from the OCV regardless of the degree of deterioration. Therefore, as in S5 and S10, for each battery cell 15A, the OCV-SOC relation data is used to specify the first SOC value X1 and the second SOC value X2 from the OCV of the battery cell 15A, and the SOC change amount ΔX can be calculated.

  The CPU 16A detects the full charge capacity of the storage battery 15 based on the first SOC value X1 specified in S5, the second SOC value X2 specified in S10, and the amount of electricity for each battery cell 15A. Is executed (S11). Next, the CPU 16A performs deterioration determination using the minimum full charge capacity of the detected full charge capacity for each battery cell 15A as the full charge capacity of the storage battery 15 (S12). Specifically, the CPU 16A has deteriorated to the extent that the storage battery 15 should be replaced when the relative amount of the full charge capacity detected this time with respect to the full charge capacity at the time of a new article is less than a threshold value (for example, 50%). Is determined. As shown in FIG. 5, the detection value and detection time of the full charge capacity are stored in the memory 16B, and an approximate line L is derived from the relative amount (capacity ratio) and the detection time for a plurality of times, and the approximation. A configuration may be used in which the remaining period ΔT until the replacement time is estimated based on the intersection of the extension line of the line L and the threshold value. In addition, the structure which derives | leads-out an approximate line from the calculated value and detection time of the full charge capacity for multiple times may be sufficient. The CPU 16A ends the deterioration determination process after performing the deterioration determination.

(Effect of this embodiment)
There is a correlation between the SOC change amount ΔX before and after the electricity amount changing process in S6 and the full charge capacity of the battery cell 15A of the storage battery 15. Further, the first SOC value X1 and the second OCV value X2 can be specified based on the first OCV, the second OCV, and the OCV-SOC relationship data. Therefore, according to the present embodiment, the full charge capacity of each battery cell 15A of the storage battery 15 can be detected based on the SOC change amount ΔX and the amount of electricity (= I × T0) charged in the amount-of-electricity changing process. it can. In addition, since the electric current is constant in the electric quantity changing process, it is possible to suppress a decrease in the detection accuracy of the full charge capacity due to an integration error or the like as compared with the configuration in which the electric current is not constant and the electric quantity is integrated.

  Further, the second OCV value X2 is specified based on the measured value of the cell voltage when the non-convergence period TM has elapsed after the electric quantity change processing. Since the electric current is constant in the electric quantity changing process, the cell voltage VM when the non-convergence period TM has elapsed and the OCV (VE) after the convergence period TE have substantially correlated. For this reason, it is possible to detect the full charge capacity within the non-convergence period TM while suppressing the variation in the specific accuracy of the value X2 of the second OCV compared to the configuration in which the current is not constant and the amount of electricity is integrated.

  Furthermore, the value X2 of the second OCV is specified based on the cell voltage value VM when the non-convergence period TM has elapsed and the divided voltage value ΔVM measured in advance. Thereby, the second OCV can be detected with higher accuracy than the configuration in which the value X2 of the second OCV is specified without considering the divided electrode value ΔVM.

  Further, with reference to information indicating the correspondence relationship between the temperature of the storage battery 15 and the polarization voltage value, a polarization voltage value ΔVM corresponding to the measured value of the temperature is derived, and the derived polarization voltage value ΔVM is used to derive the first value. A 2OCV value X2 is specified. Thereby, even if polarization voltage value (DELTA) VM fluctuates by the temperature change of the storage battery 15, it can suppress that the specific precision of 2nd OCV falls by the fluctuation | variation.

<Embodiment 2>
FIG. 6 shows a second embodiment. The difference from the first embodiment is in the deterioration determination process, and the other points are the same as in the first embodiment. Therefore, the same reference numerals as those in the first embodiment are given and the redundant description is omitted, and only different points will be described next.

  The memory 16B stores OCV-SOC related data when the battery cell 15A of the storage battery 15 is in a discharged state. The memory 16B also stores the polarization voltage value when the battery cell 15A of the storage battery 15 is discharged at a constant current I for a fixed time T0, then the discharge is stopped, and the storage battery 15 is left open for a non-convergence period TM. ΔVM is stored.

  As illustrated in FIG. 6, the CPU 16 </ b> A controls the power conversion device 13 to execute an initial charging process in which the storage battery 15 is charged with the power from the ground charging facility 30 until the SOC reaches the initial value X0. Specifically, the CPU 16A charges the storage battery 15 (S21). For example, among the cell voltages of the plurality of battery cells 15A constituting the storage battery 15, the minimum cell voltage value is the initial value X0 in the OCV-SOC related data. It is determined whether or not the value is equal to the open circuit voltage corresponding to (S22). The initial value X0 is preferably set within a range of 80% ± 10%.

  If the CPU 16A determines that the minimum cell voltage is not the same as the open circuit voltage corresponding to the initial value X0 (S22: NO), it continues charging, and if it is the same (S22: YES), it stops charging. (S23). In S <b> 26, the CPU 16 </ b> A controls the power converter 13 with the breaker 18 in a closed state, and executes an electric quantity changing process in which constant current discharge is performed at a current value I for a predetermined time T <b> 0. At this time, the electric power discharged from the storage battery 15 is supplied to the overhead line 40 or the auxiliary power supply device 19. The power conversion device 13 is an example of a discharge unit. In S29, for each battery cell 15A, the CPU 16A calculates an OCV value V2 (= V + ΔVM) from the measured value V of the cell voltage and the polarization voltage value ΔVM.

  According to the present embodiment, the full charge capacity of each battery cell 15A of the storage battery 15 can be detected based on the SOC change amount and the amount of electricity discharged in the amount-of-electricity changing process of S26. In addition, since the electric current is constant in the electric quantity changing process, it is possible to suppress a decrease in the detection accuracy of the full charge capacity due to an integration error or the like as compared with the configuration in which the electric current is not constant and the electric quantity is integrated.

  Further, in the electric quantity changing process, the electric power discharged from the storage battery 15 is supplied to the overhead line 40. Therefore, the discharged power from the storage battery 15 can be used effectively. Furthermore, the internal resistance of the storage battery 15 increases as the temperature decreases. For this reason, in the first embodiment in which charging is performed in the power change process (S6), for example, at a low temperature of 10 degrees or less, the cell voltage may become extremely high and constant current control may not be performed. On the other hand, in the present embodiment, since the discharge is performed in the power change process (S26), the deterioration determination process can be executed under a lower temperature state than in the first embodiment.

<Other embodiments>
The technology disclosed in this specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.

  In the embodiment described above, the battery management device 16 that executes each process of the deterioration determination process by the CPU 16A is taken as an example of the control unit. However, the control unit is not limited to this, and a configuration in which each process is executed only by one or a plurality of CPUs, a configuration in which each process is executed only by a hardware circuit such as an ASIC (Application Specific Integrated Circuit), a hardware circuit, A configuration in which each process is executed by both CPUs may be used. For example, a part or all of the deterioration determination process may be executed by a separate CPU or hardware circuit. Moreover, the structure which a person performs a part or all of the said deterioration determination process may be sufficient.

  In the above embodiment, as an example of the deterioration determination program, a program stored in the memory 16B having a RAM or a ROM is taken as an example. However, the deterioration determination program is not limited to this, and may be a non-volatile memory such as a hard disk device or flash memory (registered trademark), a storage medium such as a CD-R, or the like.

  In the said embodiment, the lithium ion battery was mentioned as an example of an electrical storage element. However, the power storage element is not limited to this, and may be another secondary battery or an electric double layer capacitor. Moreover, the electrical storage element from which the correlation of OCV and SOC differs at the time of a new article and a deterioration may be sufficient (refer Japanese Patent Application No. 2010-272365).

  In the said embodiment, the battery monitoring board | substrate 17B incorporated in the storage battery 15 was mentioned as an example as an example of a voltage measurement part. However, the voltage measurement unit is not limited to this, and may be a voltage sensor or the like provided outside the storage battery 15. Moreover, what was installed in the exterior of the storage battery 15 as a temperature measurement part may be used.

  In the above embodiment, the battery management device 16 may be configured to change at least one of the current value I during constant current charging, the fixed time T0, and the non-convergence period TM, for example, by an instruction from a host device (not shown). Good. However, in the case of this configuration, the polarization voltage value ΔV2 needs to be calculated and stored in the memory 16B in advance for each combination of the current value I, the fixed time T0, and the non-convergence period TM.

  In the above embodiment, the CPU 16A may be configured to determine the deterioration degree of the storage battery 15 based on the change in the SOC change amount ΔX that is calculated as needed. In addition, the CPU 16A calculates a relative amount (difference or ratio) of the calculated SOC change amount ΔX with respect to the SOC change amount ΔX at the time of a new product, and when the relative amount becomes a predetermined value or less, the replacement time The structure which determines with it may be sufficient. In these configurations, it is possible to determine the deterioration of the storage battery 15 without detecting the full charge capacity.

  In the above-described embodiment, before the execution of the deterioration determination process, the railway vehicle 10 is traveling, and there is a high possibility that the state (discharge state / charge state) of the storage battery 15 and the charge / discharge current are sequentially changed. For this reason, unlike the second OCV specifying process, the first OCV specifying process does not apply the process of specifying the OCV based on the terminal voltage and the polarization voltage value when the non-convergence period has elapsed. However, if the fluctuation of the state of the storage battery 15 before the execution of the deterioration determination process is within a predetermined range or the state can be specified, the non-convergence period for the first OCV specifying process is the same as the second OCV specifying process. You may apply the process which specifies OCV based on the terminal voltage and polarization voltage value at the time of progress.

  In the above embodiment, the initial discharge process or the initial charge process for discharging or charging the storage battery 15 until the SOC reaches the initial value X0 is performed before the execution of the first OCV specifying process. However, the configuration is not limited to this, and an initial discharge process or an initial charge process may not be performed. However, if it is the structure of the said embodiment, it can suppress that it becomes an overdischarge and an overcharge by a voltage conversion process. Further, by adjusting the SOC to a value close to the initial SOC before the start of the voltage conversion process, it is possible to improve the accuracy of the deterioration determination of the storage battery 15 as compared with the configuration in which the initial discharge process or the initial charge process is not performed. it can.

  DESCRIPTION OF SYMBOLS 10: Railway vehicle 13: Power converter 14: Power storage system 15A: Battery cell 17B: Battery monitoring board 16: Battery management apparatus

Claims (5)

A power storage device for a railway vehicle that travels with the power of a power storage element,
The power storage element;
A voltage measuring unit for measuring a terminal voltage of the power storage element;
A temperature measuring unit for measuring the temperature of the electricity storage element;
Correlation between the temperature of the storage element, the polarization voltage value of the storage element and the OCV and SOC of the storage element when a non-convergence period has elapsed before the terminal voltage of the storage element at that temperature has converged to OCV Memory for storing information about ,
A charging unit that charges the power storage element with electric power from an external power source;
A control unit,
The controller is
A first SOC specifying process for specifying a first OCV of the power storage element based on a measurement result of the voltage measuring unit, and specifying a first SOC corresponding to the first OCV in the correlation;
After the execution of the first SOC specifying process, the charging unit charges the storage element with a constant current for a certain period of time;
Refer to the information in the memory based on the measurement results of the voltage measurement unit and the temperature measurement unit when the non-convergence period has elapsed after the terminal change of the electricity storage element has converged to OCV after the electric quantity change processing. A second SOC specifying process for specifying a second OCV of the power storage element and specifying a second SOC corresponding to the second OCV in the correlation;
A capacity detection process for detecting a full charge capacity of the electric storage element based on an SOC change amount that is a difference between the first SOC and the second SOC and an electric amount charged in the electric quantity change process; A power storage device for a railway vehicle. A power storage device for a railway vehicle according to claim 1,
The railway vehicle travels in an overhead line section connected to an overhead line and a non-overhead section not connected to the overhead line,
In the overhead line section, the control unit
In the electric quantity changing process, the charging unit charges the power storage element with electric power supplied from the overhead wire electrically connected to the charging unit. A power storage device for a railway vehicle that travels with the power of a power storage element,
The power storage element;
A voltage measuring unit for measuring a terminal voltage of the power storage element;
A temperature measuring unit for measuring the temperature of the electricity storage element;
Correlation between the temperature of the storage element, the polarization voltage value of the storage element and the OCV and SOC of the storage element when a non-convergence period has elapsed before the terminal voltage of the storage element at that temperature has converged to OCV Memory for storing information about ,
A discharge part for discharging the electric power of the electricity storage element to the outside;
A control unit,
Information indicating a correspondence relationship between the temperature and the polarization voltage value is stored in the memory,
The controller is
A first SOC specifying process for specifying a first OCV of the power storage element based on a measurement result of the voltage measuring unit, and specifying a first SOC corresponding to the first OCV in the correlation;
After the first SOC specifying process is executed, the discharge unit discharges the power storage element at a constant current for a fixed time;
Refer to the information in the memory based on the measurement results of the voltage measurement unit and the temperature measurement unit when the non-convergence period has elapsed after the terminal change of the electricity storage element has converged to OCV after the electric quantity change processing. A second SOC specifying process for specifying a second OCV of the power storage element and specifying a second SOC corresponding to the second OCV in the correlation;
A capacity detection process for detecting a full charge capacity of the power storage element based on an SOC change amount which is a difference between the first SOC and the second SOC and an electric quantity discharged in the electric quantity change process; A power storage device for railway vehicles. A power storage device for a railway vehicle according to claim 3,
The railway vehicle travels in an overhead line section connected to an overhead line and a non-overhead section not connected to the overhead line,
In the overhead line section, the control unit
In the electrical quantity changing process, a power storage device for a railway vehicle that supplies power discharged from the power storage element by the discharge unit to the overhead line electrically connected to the discharge unit. A power storage device for a railway vehicle according to any one of claims 1 to 4,
The power storage device for a railway vehicle in which the correlation between the OCV and the SOC is unchanged regardless of deterioration .

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