JP2019057455A - Control apparatus of secondary battery and control method - Google Patents

Abstract

To suppress deterioration of a battery during cooling of a secondary battery at a low temperature, and an output fluctuation in accordance with variation of the deterioration of the battery.SOLUTION: A control apparatus of a secondary battery, comprises: the secondary battery; a cooling device that inlets an outer air and cools the secondary battery by the outer air; a first temperature sensor detecting a temperature of the outer air; a second temperature sensor detecting the temperature of the secondary battery; and a control part that controls an operation of the secondary battery and the cooling device. The control part changes a cooling speed by the cooling device when a difference of a first inner resistance value of the secondary battery at the temperature of the outer air detected by the first temperature sensor and a second inner resistance value at the temperature of the secondary battery detected by the second temperature sensor is less than and is equal to a predetermined threshold value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device and a control method for a secondary battery, and is particularly suitable for a secondary battery for a railway vehicle.

  At present, global environmental problems have been greatly improved, and in order to prevent global warming, reduction of carbon dioxide emissions is required in every situation. Against this background, automobiles using gasoline engines, which are one of the major sources of carbon dioxide, are being replaced by hybrid electric cars and electric cars.

  Storage batteries include chargeable / dischargeable lithium ion secondary batteries, nickel metal hydride batteries, lead batteries, electric double layer capacitors and the like, and in particular, two or more battery cells having high output density such as lithium ion batteries. Secondary battery systems are widely used for industrial applications, and in recent years, secondary battery systems with higher voltages and larger capacities have begun to become popular as power storage systems for vehicles.

  This secondary battery system is also widely used in the field of railway vehicles in order to save energy. The types include hybrid power trains that combine a generator driven by a diesel engine and a secondary battery system to supply power to the motor, and those that are installed in electric vehicles and have no regenerative load. A train system that absorbs secondary batteries, and a hybrid train consisting of a train line and a secondary battery system for the purpose of eliminating overhead lines (running between stations using the secondary battery system as a power source and charging the secondary battery system at the station ).

  A large-sized secondary battery represented by a power source for power needs to have a high output and a large capacity. Therefore, a storage battery module that constitutes such a large secondary battery is generally configured by connecting a plurality of battery cells in series and parallel. Moreover, a lithium ion battery is frequently used for each battery cell.

  In general, the storage battery has a usable temperature range that guarantees operation as a safe product and a usable temperature range that can satisfy a predetermined performance as a specification of the device. Operating the storage battery beyond the upper and lower limits of these operating temperature ranges is a cause of failure of the battery system and a cause of shortening the life of the battery system, and must be avoided. In general, in a secondary battery such as a lithium ion battery, deterioration is accelerated and accelerated every time storage and charging / discharging are repeated at high temperatures.

  For example, when mounted on a car, the environmental temperature of the storage battery rises due to reflection from asphalt in summer and parking in the sun, and there is a concern that the battery temperature rises when it is cooled by the outside air and the deterioration progresses . Therefore, the battery cooling method is important. For example, Patent Document 1 discloses that the air volume adjustment of the air blower for the battery temperature and the outside air temperature is performed when the outside air temperature exceeds the battery temperature than when the air temperature is lower than the battery temperature. A technique for controlling so as to reduce the amount is disclosed.

JP 2014-148245 A

Since a railway vehicle is much larger in size and weight than an automobile, a storage battery system applied to the railway vehicle requires a large amount of energy and a size of the storage battery system.
FIG. 2 is a diagram illustrating an example of storage when a storage battery system is mounted on a railway vehicle. In the railway vehicle, the traveling direction is the longitudinal direction, and the sleeper direction is the minor axis direction. When a storage battery is mounted, the storage battery system is large in size, so a battery box that houses the storage battery on the roof side of the cabin vehicle shown in FIG. 2 (a) or on the lower floor side of the vehicle shown in FIG. 2 (b). 11 is mounted on the vehicle. Alternatively, the storage battery may be stored in a dedicated vehicle (not shown). Since the vehicle is long and narrow, when the battery is cooled by outside air, a temperature difference is generated in the plurality of storage batteries inside than the automobile.

  The battery box here refers to a battery module (hereinafter also referred to as “assembled battery”) constituted by a plurality of single cells (hereinafter also referred to as “cells”) as an assembled battery, or the battery module. Furthermore, it indicates a power storage device in which at least one or more storage battery units configured and built in a housing are housed in one housing unit. In addition to the battery, the battery box includes a control board, a sensor, and other electromechanical structural parts.

  FIG. 3 is a diagram illustrating an example of the characteristic of the internal resistance with respect to the temperature of the secondary battery. In a secondary battery, particularly a lithium ion battery, as shown in FIG. 3, when the internal resistance value at 25 ° C. is used as a reference, the resistance becomes remarkably large at a low temperature. It has been found that when a temperature difference occurs in the assembled battery, the fluctuation of input / output becomes large, the system voltage becomes unstable, and a problem such as a large variation in deterioration of the storage battery occurs. In particular, in cold regions, it has become clear in recent years that battery deterioration increases when cooled by low-temperature air.

  In the method described in Patent Document 1, when the outside air is lower than the battery temperature, the air volume is large even when the battery is at a low temperature. In the case of a lithium ion battery, the internal resistance becomes remarkably large at a low temperature. There is a concern that the system will stop. Moreover, in a railway vehicle, there is a concern that the traveling wind at the time of traveling is different in the environment on the forward path and the return path, and the temperature variation becomes large. In the prior art, a reduction in capacity due to deterioration of the secondary battery at a high temperature is considered, but an increase in internal resistance due to a low temperature is not considered.

A control device for a secondary battery according to the present invention includes a secondary battery, a cooling device including a plurality of coolers that cool the secondary battery by the outside air that has been taken in and taken in, and a first temperature that detects the temperature of the outside air. A sensor, a plurality of second temperature sensors that detect the temperature of the secondary battery, and a control unit that controls the operation of the secondary battery and the cooling device, and the control unit detects the temperature of the outside air detected by the first temperature sensor Each of the coolers is controlled by the information and the temperature information of the secondary battery detected by the second temperature sensor.
In addition, the control unit may include a first internal resistance value of the secondary battery at the temperature of the outside air detected by the first temperature sensor and a second value of the secondary battery at the temperature of the secondary battery detected by the second temperature sensor. (2) The cooling rate by the cooling device is changed depending on whether the difference between the resistance value and the internal resistance value is less than a predetermined threshold value or more.

  According to the present invention, variation in battery temperature of a large-sized storage battery system is suppressed, and it is possible to stably use a storage battery for a long time by suppressing variation in battery deterioration and change in resistance value. In particular, it is effective for a large storage battery system for a railway vehicle.

It is a figure which shows the control flow of the secondary battery control system which concerns on this invention. It is a figure which shows the example of a storage in the case of mounting a storage battery system in a rail vehicle. It is a figure which shows the characteristic of the internal resistance with respect to the temperature of a secondary battery. It is a figure which shows the basic composition of the secondary battery control system which concerns on this invention. It is a figure which shows the structural example of the hybrid vehicle system driven by the engine and electrical storage apparatus based on this invention. It is a figure which shows the general structural example of the electrical storage apparatus shown in FIG. It is a figure which shows the example of arrangement | positioning of the battery box which concerns on this invention in the case of mounting a storage battery in a rail vehicle. It is sectional drawing which shows the example of arrangement | positioning (arrangement example 1) which looked at the inside of the battery box which concerns on this invention from the upper part. It is sectional drawing which shows another example of arrangement | positioning (arrangement example 2) inside the battery box which concerns on this invention. It is sectional drawing which shows another example of arrangement | positioning (placement example 3) inside the battery box which concerns on this invention. It is sectional drawing which shows another example of arrangement | positioning (placement example 4) inside the battery box which concerns on this invention. It is a figure which shows the example of arrangement | positioning of a battery module by sectional drawing of the battery box which concerns on this invention. It is a side view which shows the structural example of the battery module inside the housing of the battery box which concerns on this invention. It is a figure which shows the graph which shows the relationship between the temperature of a battery, and a resistance value, and the graph which shows the relationship between battery temperature and an air volume wind speed. It is a figure for demonstrating the control system which changes the air volume wind speed based on this invention. It is a figure which shows an example of the fan control in the case of using a fan as a cooling device which concerns on this invention. It is a figure which shows an example of the flowchart for the cooling control which concerns on this invention. It is a figure which shows an example of the flowchart of the battery control which concerns on this invention. It is a figure which shows the flow of general battery control. It is a figure which shows the time transition of the allowable electric current command value at the time of the cooling control which concerns on this invention. It is a figure which shows the resistance value of the battery decided by the parameter of temperature and SOC.

Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, the secondary battery is simply referred to as “battery”.
FIG. 1 is a diagram showing a control flow of a secondary battery control system according to the present invention.
The outside air temperature Tout, the battery maximum temperature Tmax, and the battery minimum temperature Tmin are detected by the detection unit 1 and then input to the temperature calculation unit 2. From the plurality of temperature information, the temperature calculation unit 2 uses the temperature difference between the outside air and the battery, the resistance difference with respect to the battery temperature, the resistance difference in the battery module based on the difference in battery temperature, and the battery temperature in the battery module housing. Calculate differences etc. At this time, reference is made to the relationship between temperature and resistance, the relationship between SOC and resistance, etc. stored in the battery characteristic information section 3.

  The results calculated by the temperature calculation unit 2 are input to the cooling control unit 4 and the allowable current calculation unit 5, respectively. A cooling control signal such as a fan operating speed is supplied from the cooling control unit 4 and an allowable current command is supplied from the allowable current calculation unit 5 to the system control unit 6 to control the battery module. The temperature calculation is executed according to a plurality of cooling devices in the entire power storage device, and cooling is performed based on the temperature calculation.

FIG. 4 is a diagram showing a basic configuration of a secondary battery control system as an example showing the embodiment of the present invention.
The secondary battery control system shown in FIG. 4 is a system for controlling the battery module 22, which is a secondary battery, and includes a detection unit 20, a battery control unit 30, a cooling condition calculation unit 40, a host control unit 60, and load control. Part 70 and a cooling device controller 71.

  The storage battery 21 is configured by connecting in series a battery module (assembled battery) 22 in which a plurality of cells (not shown) having a positive electrode and a negative electrode are connected. The storage battery 21 is connected to a load (not shown) and supplies power to the load.

  The detection unit 20 detects various information related to the state of the storage battery 21. For example, various data such as the total current and total voltage of the storage battery 21, the environmental temperature in the housing, the maximum battery temperature, the average battery temperature, the minimum battery temperature, the temperature of each cell, and the cell voltage are detected. Various data detected by the detection unit 20 are input to the battery control unit 30 and the cooling condition calculation unit 40, respectively. Information on the outside air temperature is also input to the cooling condition calculation unit 40.

  The battery control unit 30 calculates the current state of charge (SOC) of the storage battery 21 based on various data input from the detection unit 20, detects an abnormal state, and calculates input / output power. Further, processing such as calculation of system power of the entire upper control unit and generation of a temperature control command is executed. These pieces of information obtained by the battery control unit 30 are input to the host control unit 60.

  The cooling condition calculation unit 40 estimates the temperature and resistance value of the storage battery 21 based on various data input from the detection unit 20 and the outside air temperature. At this time, the SOC value calculated by the battery control unit 30 from the input data from the detection unit 20 is used. Based on the current temperature of the storage battery 21 and the current outside air temperature, the current cooling flow rate is calculated from the location in the battery module where the temperature is detected and the resistance value, and is compared with a preset cooling flow rate. A target cooling flow rate is determined based on the comparison result.

  The host control unit 60 calculates a control command based on the target cooling flow rate obtained by the cooling condition calculation unit 40, outputs the control command to the cooling device control unit 71, and calculates a control command for controlling the operating state of the load. And output to the load control unit 70.

The load control unit 70 executes load control in accordance with a control command from the host control unit 60 based on the output of the battery control unit 30.
The cooling device control unit 71 executes control of the cooling device in accordance with a control command from the host control unit 60.

FIG. 5 is a diagram illustrating a configuration example of a hybrid vehicle system driven by the engine and the power storage device.
The hybrid vehicle system includes an engine 201, a generator 202 that is driven by the engine 201 and outputs AC power, a converter device 203 that converts AC power into DC power, an inverter device 204 that converts DC power into AC power, and drives a railway vehicle. The main components are an electric motor 205 that performs power transmission, a speed reducer (not illustrated) that decelerates the output of the electric motor 205 and transmits the output to a wheel shaft (not illustrated), and a power storage device 206.

  A generator 202 directly connected to the engine 201 through a shaft generates three-phase AC power of U, V, and W, and the converter device 203 converts the AC power into DC power and outputs the DC power. The inverter device 204 converts the DC power output from the converter device 203 into three-phase AC power having a variable voltage and variable frequency, and supplies it to the induction motor 205.

  Power storage device 206 is connected in parallel to the output side (DC side) of converter device 203 and replenishes power when the vehicle is started. The smoothing capacitor 207 is connected in parallel to the input side (DC side) of the inverter device 204 and suppresses fluctuations in the inverter input voltage. SIV211 is a static inverter that generates electric power for use in the vehicle.

  On the other hand, the control unit 210 executes converter control calculation based on the converter output current Is detected by the current detector 209a, the smoothing capacitor voltage detected by the voltage detector 208, and the generator rotation frequency, and A converter PWM control signal is output. Further, the control unit 210 performs inverter control calculation based on the motor currents Iu, Iv and Iw detected by the current detectors 209b, 209c and 209d, the smoothing capacitor voltage detected by the voltage detector 208 and the motor rotation frequency, An inverter PWM control signal is output to the inverter device 204.

  A battery state calculation unit (not shown) of the power storage device 206 calculates the operating state of the power storage device 206 from the total current, total voltage, temperature of the power storage device 206, and environmental temperature. Further, the control unit 210 that has received the information on the power storage device 206 output from the battery state calculation unit determines the operating state of the power storage device 206 and outputs a charge / discharge control signal for the power storage device 206.

FIG. 6 is a diagram illustrating a general configuration example of the power storage device 206 illustrated in FIG. 5.
The storage battery 21 in which the current detection device 41 and a plurality of battery modules (assembled batteries) 22 are connected in series is further connected in parallel. The total voltage detected by the voltage detection device 31 and the current value detected by the current detection devices 41 and 42 are input to the state detection unit 50. The state detection unit 50 determines the state of charge (SOC) and soundness (overvoltage) of the battery. , Overcurrent) and the like, and information such as allowable current and allowable power is output to the host control unit 60.

  Based on a control command input from the host control unit 60, the load control unit 70 performs charging / discharging of the storage battery 21. The control unit 210 shown in FIG. 5 corresponds to the host control unit 60. The control unit 210 shown in FIG. 5 also outputs a control signal for the battery cooling device.

  FIG. 7 shows an example of arrangement of battery boxes when a storage battery is mounted on a railway vehicle, and is an example of arrangement of battery boxes 11 on the roof of the vehicle body 12. The overall controller 10 including the control command generator is under the floor (see FIG. 2).

  In the case of the arrangement example of the battery case 11 described above, the path of the cooling air with respect to the battery case 11 is indicated by an arrow in FIG. In the arrangement of FIG. 7A, the cooling air is taken in and discharged almost perpendicularly to the traveling direction. In the arrangement shown in FIG. 7B, cooling air is taken in and discharged substantially parallel to the traveling direction. In either case, since there are a plurality of storage batteries in the battery box, the battery temperature in the vicinity of the exhaust outlet is generally higher than that in the vicinity of the intake opening. The same applies to the battery box arranged under the floor as shown in FIG.

Next, an arrangement example of the internal arrangement of the battery box 11 will be described with reference to FIGS. Here, the battery box 11 includes a plurality of storage battery units 23 inside, and has a structure in which a cooler 34 is provided at least for each storage battery unit 23, and the plurality of coolers 34 constitute a cooling device.
FIG. 8 is a cross-sectional view showing an arrangement example 1 when the internal arrangement of the battery box 11 is viewed from above. In the present invention, as shown in FIG. 8, the battery box 11 has a plurality of storage battery units 23 provided with one or more battery temperature sensors 32 for detecting the battery temperature, a plurality of coolers 34, or the outside of the casing of the battery box 11. An outside air temperature sensor 33 for obtaining the outside air temperature is provided. Here, the battery temperature sensor 32 is installed, for example, on the surface of the housing of the storage battery unit 23, and the outside air temperature sensor 33 is installed, for example, outside the plurality of coolers 34 or outside the casing of the battery box 11.

  With the above configuration, the resistance value of the battery at the outside air temperature is compared with the resistance value of the battery at the lowest temperature in the battery. To do. Thereby, it can suppress that the battery surface temperature falls rapidly at the time of taking in external air, and can suppress that the internal resistance of a storage battery changes rapidly. In addition, the deterioration of the battery due to the temperature difference between the surface and the inside of the unit cell can be suppressed, and the power storage system can be used for a long time.

  Furthermore, when the battery temperature inside each storage battery unit 23 is different, the flow rate of the refrigerant is individually changed by the cooler 34 of each storage battery unit 23. As a result, when the fan speed is uniformly changed, it is possible to reduce the variation in cell temperature, which has a gradient depending on the position of the battery box, and the battery temperature can be made uniform. Further, since the variation in battery resistance is reduced, the variation in output can be suppressed, and the influence of variation in deterioration acceleration due to temperature is also reduced, so that the battery usage period can be extended.

  Here, the installation position of the outside air temperature sensor 33 may be anywhere as long as the outside air temperature can be acquired, but it is most preferable that the outside air temperature sensor 33 be located at a position where the outside air temperature in the vicinity of the intake port can be acquired. The plurality of battery temperature sensors 32 provided in the storage battery unit 23 are desirably arranged in a form including a cell having the highest temperature and a cell having the lowest temperature. Even when the battery temperature sensor 32 can detect only one temperature in the storage battery unit 23, the same control is possible. In this case, if the battery temperature sensor 32 is arranged in the vicinity of the battery cell or the refrigerant intake port where the temperature becomes highest, the effect becomes higher.

  FIG. 9 is a cross-sectional view showing an arrangement example 2 which is another internal arrangement of the battery box 11. In addition to the outside air temperature sensor 33 that detects the outside air temperature, a temperature sensor 35 that detects the temperature inside the casing of the battery box 11 is provided inside the battery box 11. When the difference between the internal temperature of the enclosure obtained by the temperature sensor 35 in the enclosure and the outside air temperature obtained by the outside air temperature sensor 33 outside the enclosure is large and rapid cooling is not desirable, the cooler 34 to the storage battery unit 23 is used. Refrigerant for cooling is taken from inside the housing, not from outside air. Further, when the battery temperature decreases and the difference from the outside air temperature reaches the threshold temperature Tth, the refrigerant is taken in from the outside air. Thereby, a sharp change in the internal battery resistance can be suppressed.

  FIG. 10 is a cross-sectional view showing another arrangement example 3. In FIG. Inside the battery box 11, there are provided a temperature sensor 35 for detecting the temperature inside the casing of the battery box 11 and an outside air temperature sensor 33 for detecting the outside air temperature in the vicinity of the cooling air intake port 13. The cooler 34 shown in FIG. 10 is a suction-type fan, and has a structure that takes in outside air from the cooling air intake port 13 and cools the storage battery module 23. Thereby, the cooling air temperature can be obtained more accurately, and the temperature variation of the battery can be suppressed by applying the above-described implementation method.

  FIG. 11 is a cross-sectional view showing another arrangement example 4, wherein (1) is a view from above, and (2) is a view from the side in the vehicle traveling direction. Arrangement example 4 does not take outside air into the storage battery unit 23 of the battery box 11, but provides a separate chamber for taking in outside air, adjusts the refrigerant temperature in the housing of the battery box 11 by the heat exchanger 36, and each storage battery unit 23. The cooler 34 (in this case, a fan) is operated to cool the storage battery unit 23. In the compartment, the temperature in the compartment is controlled by a fan 34a from an outside air intake (not shown). The number of the outside air temperature sensors 33 and the temperature sensors 35 in the battery box 11 may be one or more. If the number of these sensors is increased, the control can be further stabilized. Conversely, if the number of these sensors is reduced, the cost can be suppressed. In the arrangement example 4, the cooling device is configured by the cooler 34 (fan) and the fan 34a provided on the compartment side.

  By using a heat sink or a heat pipe, the heat exchanger 36 can prevent a continuity failure or a short-circuit accident caused by bringing dust into the battery module main body or the control board without directly contacting the outside air with the battery module. It becomes. As a result, it is possible to eliminate a filter that prevents adhesion of dust when taking in outside air, in particular, soot from the exhaust gas of diesel engines or iron powder cut from rails. Furthermore, it is possible to reduce the number of parts and maintain maintenance such as filter replacement.

  If a heat sink with a heat pipe is used for the heat exchanger 36, heat transportability can be improved, and further downsizing of the system can be achieved. When a heat pipe is used for the heat exchanger 36, a refrigerant having a high specific heat is used for the heat pipe for heat exchange and is circulated by a pump, and the refrigerant flow rate is a control method according to the present invention using the outside air temperature. By applying, it becomes possible to cool more effectively. In addition, cooling can be implemented more effectively by preparing a plurality of heat exchangers and individually adjusting the flow rate.

  FIG. 12 is a diagram illustrating an arrangement example of the battery module 22 by a cross-sectional view of the battery box 11. In this configuration example, the cooling air intake port 13 and the exhaust air port 19 face each other in the sleeper direction, and the battery modules 22 are stacked in two stages in the battery box 11.

  FIG. 13 is a side view showing an example of the structure of the battery module 22 inside the housing. An example in which six unit cells 18 are mounted is shown. (A) is the structure which provided the opening part 17 in the upper surface, installed the exhaust duct 16 in the outer side, and provided the several opening part 17 in the bottom face. (B) is provided with an opening 17 above one vertical side and an exhaust duct 16 on the outside, and a plurality of openings 17 on the bottom and an opening 17b below the opposite vertical side. Structure. (C) is a structure in which the opening 17 is provided at the middle height of one vertical side surface, the exhaust duct 16 is installed outside thereof, and the opening 17 is provided at the middle height of the opposite vertical side surface. is there. In addition to those types, other types of structures may be employed depending on the installation location, installation mode, installation environment, and the like.

Next, the relationship between the battery temperature and the resistance value in the present invention and the method of changing the air flow rate according to the battery temperature will be described in detail. Here, the resistance value of the battery refers to the internal resistance value of the battery, and is hereinafter also referred to as “resistance value” for short.
FIG. 14 is a graph showing the relationship between the battery temperature and the resistance value in the upper row, and the graph showing the relationship between the battery temperature and the air flow rate in the lower row. As shown in FIG. 3, the resistance value of the battery changes depending on the temperature, and also changes depending on the SOC (refer to FIG. 21 for the point where the resistance value of the battery changes depending on the SOC). Therefore, the allowable power of the battery can be calculated with reference to a relational expression or a data map of the resistance value with respect to the SOC and the temperature.

  As shown in the upper graph of FIG. 14, the resistance value of the battery at the outside air temperature Tout is Rout, the resistance value at the lowest cell temperature Tmin (hereinafter referred to as “battery minimum temperature”) in the battery box is R1, and the battery The resistance value at the maximum cell temperature Tmax in the box (hereinafter referred to as “battery maximum temperature”) is R2. Further, the difference Rout−R1 between the resistance value Rout at the outside air temperature Tout and the resistance value R1 at the lowest battery temperature is ΔRu, and the difference between the resistance value R1 at the lowest battery temperature and the resistance value R2 at the highest battery temperature is the temperature. A difference ΔR1 is defined as a difference between a resistance value Rout at the outside temperature and a resistance value R2 at the highest battery temperature.

  Then, when ΔRu is cooled by the outside air in a large state, the resistance value of the lowest temperature cell partially increases and the temperature variation expands to ΔR2. In this state, the battery is used in an unstable manner. The threshold value a at which the change in resistance value is allowed is appropriately determined from the SOC at each temperature and the battery characteristics.

  When the difference ΔRu between the resistance value at the outside air temperature and the resistance value at the lowest battery temperature is ΔRu <threshold a, the cooling rate is determined according to the normal cooling specification. Further, when ΔRu is ΔRu> 0 and ΔRu ≧ threshold a, the cooling rate is slower than the target rate when the maximum battery temperature exceeds the threshold Tthu of the battery temperature at the start of cooling and the cooling is started. To do. Accordingly, when the battery temperature gradually changes and ΔRu enters a region below the threshold value a without rapidly cooling the battery surface, the cooling rate is increased to the normal use value to accelerate the cooling. Accordingly, after suppressing a steep temperature change, the battery can be cooled to lower the maximum temperature and extend the life of the battery. In addition, steep output fluctuations can be suppressed, leading to stable running. On the other hand, the air volume or wind speed is increased when the battery temperature is high, and is decreased at a low temperature to moderate the temperature change.

  As described above, the battery resistance value Rout at the time of taking in the outside air is calculated, and when the difference ΔRu between the value Rout and the resistance value R1 at the battery minimum temperature is equal to or greater than the threshold value a, the cooling rate at the start of cooling. However, in a place where the battery temperature is high, the cooling rate is increased. In particular, in the case of a large number of batteries, a plurality of cooling devices are provided depending on the installation location, and it is more effective to individually control a plurality of cooling devices (for example, fans). Control each cooling device.

  FIG. 15 is a diagram for explaining a control method for changing the air flow rate from the relationship between the battery temperature and the resistance value. The cooling rate is changed according to the time from the start of blowing. For example, in the region where ΔRu is less than the threshold value a and changes little, cooling is performed at a constant high cooling rate as shown in FIG. Further, when the difference between the outside air temperature and the battery temperature is large and ΔRu is greater than or equal to the threshold value a, the cooling rate is gradually increased as shown in FIG. 15D, and ΔRu has become smaller (for example, ΔRu is smaller). Control is performed so that the gradient of the cooling rate is increased when the value becomes less than the threshold value a). Furthermore, an area to be controlled as shown in FIG. 15C or an area to be controlled as shown in (B) may be provided depending on the battery temperature.

FIG. 16 is a diagram illustrating an example of fan control when a fan is used as a cooling device.
As one control method, FIG. 16A shows a method of controlling the fan duty with respect to the battery temperature. For example, as shown in the figure, a fan duty of 0 is maintained until a certain temperature is reached (until the temperature Ts between T4 and T5 in the figure), and at higher battery temperatures, the fan duty depends on the temperature. The air volume is controlled by tilting up to the maximum.

  As another control method, FIG. 16B is a method (fan switch control) in which the operation of the fan is controlled by the temperature of the lowest temperature cell in the storage battery 21 and the temperature sensor (for example, thermistor) of the highest temperature cell. is there. The temperature at which the fan is operated is determined according to the battery characteristics, and control is performed with a plurality of signals (in the figure, on / off signals for the thermistor 1 and the thermistor 2) so that the characteristics can be secured most. At this time, the fan may be at a uniform operating temperature, but a plurality of cooling fans are provided in accordance with the arrangement of the battery modules in the battery box 11, and each fan duty is individually controlled so as to be the target battery temperature. Thereby, variation in battery temperature can be reduced, input / output characteristics are stabilized, and battery power can be used effectively. Furthermore, since variations in deterioration due to temperature are suppressed, the battery system can be used for a longer time.

FIG. 17 is a diagram showing an example of a flowchart for cooling control of the secondary battery control system according to the present invention.
The battery voltage, current and temperature are measured (step S1), the SOC is calculated from the measured values (step S2), and the voltage and SOC are recorded (step S3).
The outside temperature and the battery temperature are collected by a plurality of temperature sensors (step S4), and it is determined whether or not the battery needs to be cooled (step S5).

  If cooling is not required (No), the fan is stopped (step S6), and the process returns to step S4 to collect the temperature. On the other hand, when cooling is required (Yes), the predicted battery resistance at the outside air temperature and the battery resistance at the current battery temperature are determined based on the measured outside air temperature, the battery temperature, and the calculated SOC (for example, FIG. (Step S7).

  Next, the calculated battery resistance difference ΔR is compared with a threshold value (step S8). If ΔR is equal to or greater than the threshold value (Yes), the fan duty is calculated (step S10), and the calculated fan duty is used. For example, the fan is operated based on the fan duty control shown in FIG. 16A (step S11).

On the other hand, if ΔR is less than the threshold value (No), the fan is operated under normal fan control (a constant cooling air volume or cooling speed) (step S9). During the operation of the fan in step S9 and step S11 described above, as a processing step, the above fan control is repeated until the variation in battery temperature falls within a certain range by returning to step S4.
The method of controlling the cooling rate when ΔR is equal to or greater than the threshold value or less than the threshold value is based on the control method described above with reference to FIGS. 14 and 15 and uses fan control as the cooling means. is there.

  By controlling based on the above flowchart, the battery temperature becomes constant, effective cooling can be achieved, rapid battery voltage fluctuation and current fluctuation can be suppressed, and battery deterioration can also be suppressed. The example explained above is a case where a fan is used for a cooling device, but even when another cooling device is employed, a control signal for controlling the cooling flow rate is calculated in step S10, and the same control is performed. Just do it.

  Moreover, in addition to the cooling control method described above, further, by using an input / output allowable power command value using the outside-air temperature prediction resistance Rout, it is possible to reduce battery load and improve system stability. it can.

  FIG. 19 is a diagram illustrating a battery control flow in a general input / output power command. From each information of the battery current I, the battery voltage V, and the battery temperature T, battery state detection and temperature calculation are performed. From the temperature calculation, the control parameter as the control representative value is changed, and the allowable current and the allowable power are calculated from the detected battery state and the control parameter. Based on this calculation amount, an input / output command is generated to charge / discharge the storage battery. Here, for the allowable current and the allowable power, command values are determined by the battery state such as the battery temperature and the SOC.

  With respect to the battery control flow described above, in the present invention, for example, based on the flowchart shown in FIG. FIG. 20 is a diagram showing a time transition of the allowable current value during the battery control.

  The outside air temperature is measured (step N1), and based on the measured value, the allowable current calculation unit 5 in FIG. 1 calculates the outside temperature predicted resistance Rout and the allowable current value Iout (step N2). As shown in FIG. 14, the allowable current value Iout at the time of the outside temperature predicted resistance Rout is smaller than the allowable current value I corresponding to the battery resistance value R1 at the lowest temperature. Therefore, in order to stabilize the control, the allowable current value Iout calculated by the outside-air temperature prediction resistance Rout is set to the allowable current value I with respect to the allowable current value I whose output is restricted at the minimum temperature before the cooling of the battery is started. The calculation unit 5 calculates and notifies the system control unit 6 of FIG. When the difference ΔI between the allowable current value Iout at the outside temperature predicted resistance Rout and the allowable current value I corresponding to the battery resistance value R1 at the lowest temperature is larger than the threshold ΔIth, the allowable current value is As shown between the points (A) and (B) in FIG. 20, it is changed and decreased toward the allowable current value Iout with an inclination (step N3).

  When the allowable current value reaches the allowable current value Iout of the outside-air temperature prediction resistance Rout, the operation of the cooling device is started (step N4). After that, the allowable current value is changed and increased with an inclination to the allowable current value I calculated by the battery temperature as between the points (C) and (D) in FIG. 20 (step N5).

  With the above flow, an effect of further extending battery life can be achieved by suppressing steep output fluctuations and further reducing the load on the battery. 4 controls the load via the load control unit 70 based on the output from the battery control unit 30, and controls charging / discharging by changing the energization time and the current value to the storage battery 21. . Thereby, the lifetime control of the storage battery 21 is attained.

Next, a time-series control mode will be described in detail with respect to the secondary battery control flowchart shown in FIG.
The allowable current value I shown in FIG. 20 is determined based on, for example, the resistance value of the battery determined by the temperature and the SOC parameter shown in FIG. 21, and decreases as the resistance value increases. As information used for this determination, information mapped to the resistance may be used, or information represented by a relational expression may be used.

  When the difference ΔI between the allowable current value I during operation (here, corresponding to the resistance value at the lowest temperature shown in FIG. 14) and the allowable current Iout at the predicted outside air temperature resistance Rout is larger than the threshold value ΔIth. As shown in FIG. 20, the allowable current value is decreased from the point (A) with a constant slope or decreased stepwise (not shown). When the allowable current value drops to Iout (B), cooling of the battery by taking in outside air is started. After starting the cooling of the battery, the allowable current value is maintained at Iout while the temperature difference between the plurality of cells is large.

  From the point (C) where the variation in the battery temperature is improved to the point (D) where the allowable current value I during operation is increased, it is increased with a certain slope. After reaching the allowable current value I during operation, the allowable current value I is maintained. Here, the threshold value ΔIth and each threshold value of the temperature difference between the plurality of cells are arbitrarily determined according to battery characteristics, response characteristics of the control device, and the like.

  According to the above control mode, it is possible to suppress a steep change in the battery current and reduce the battery load, and thus it is possible to suppress the deterioration rate of the battery. In addition, the stability during driving of the vehicle is improved and the duration of the energy saving effect is extended, so that the usage period of the vehicle can be extended.

  Furthermore, a relational expression or map of deterioration with respect to the battery temperature is provided, and a recording device that records the flow rate and temperature change for cooling and a learning device that extracts the relationship between the flow rate and the battery temperature from the recording device are provided. It may be. Thereby, more optimal cooling control can be implemented by sequentially updating a map indicating the relationship between the flow rate and the battery temperature to control the flow rate. By providing this learning device, the optimal cooling rate (flow rate) can be selected even when battery deterioration progresses in real time, so the power storage device can be used for a long time with more stable operation by adapting to the load and battery temperature. It becomes possible.

  In addition, this invention is not limited to an above-described Example, The other embodiment considered within the range of the technical idea of this invention is also included in the scope of the present invention.

1 detection unit, 2 temperature calculation unit, 3 battery characteristic data unit, 4 cooling control unit,
5 Allowable Current Calculation Unit, 6 System Control Unit, 10 General Control Unit, 11 Battery Box,
12 body, 13 cooling air inlet, 15 vehicle, 16 exhaust duct,
17, 17b opening, 18 unit cell, 19 air outlet, 20 detector 21 storage battery,
22 battery modules (assembled batteries), 23 storage battery units, 30 battery control units,
31 voltage detector, 32 battery temperature sensor, 33 outside temperature sensor, 34 cooler,
35 temperature sensor, 36 heat exchanger, 40 cooling condition calculation unit,
41, 42 Current detection device, 60 Host control unit, 70 Load control unit,
71 Cooling device control unit, 201 engine, 202 generator, 203 converter device,
204 inverter device, 205 induction motor, 206 power storage device,
207 smoothing capacitor, 208 voltage detector, 209 current detector,
210 control unit, 211 SIV

Claims (18)

A secondary battery,
A cooling device comprising a plurality of coolers that take in outside air and cool the secondary battery with the outside air taken in;
A first temperature sensor for detecting the temperature of the outside air;
A plurality of second temperature sensors for detecting the temperature of the secondary battery;
A control unit for controlling the operation of the secondary battery and the cooling device,
The controller controls each of the coolers based on temperature information of the outside air detected by the first temperature sensor and temperature information of the secondary battery detected by the second temperature sensor. Battery control device. The control apparatus for a secondary battery according to claim 1,
The control unit includes a first internal resistance value of the secondary battery at the temperature of the outside air detected by the first temperature sensor and the second temperature at the temperature of the secondary battery detected by the second temperature sensor. A control apparatus for a secondary battery, wherein the cooling rate by the cooler is changed depending on whether the difference in resistance value from the second internal resistance value of the secondary battery is less than a predetermined threshold value or more. The control apparatus for a secondary battery according to claim 1,
The control unit controls the cooling rate to a constant high speed state when the resistance value difference is less than the predetermined threshold value, and reduces the cooling rate to a low speed state when the resistance value difference is greater than the predetermined threshold value. The control apparatus of the secondary battery, wherein the control is performed so that the gradient of the cooling rate is increased from the time when the resistance value difference becomes less than the predetermined threshold. The control apparatus for a secondary battery according to claim 1,
A calculation unit for calculating the state of charge of the secondary battery is provided in the control unit,
When the control unit determines that the secondary battery needs to be cooled based on the temperature of the outside air and the temperature of the secondary battery, the controller charges the secondary battery with the first internal resistance value and the second internal resistance value. Comparing the resistance value difference with the predetermined threshold value by taking into account the state, and if the resistance value difference is less than the predetermined threshold value, operating the cooler at a constant cooling rate, When the resistance value difference is equal to or larger than the predetermined threshold, the cooling rate is set to a low speed until the temperature of the secondary battery reaches a predetermined temperature, and when the temperature of the secondary battery exceeds the predetermined temperature, the cooling is performed. A control device for a secondary battery, characterized by increasing a slope of speed. A secondary battery composed of a plurality of battery cells;
A cooling device comprising a plurality of coolers that take in outside air and cool the secondary battery with the outside air taken in;
A first temperature sensor for detecting the temperature of the outside air;
A plurality of second temperature sensors for detecting the temperature of the secondary battery;
A control unit for controlling the operation of the secondary battery and the cooling device,
The controller is
Based on the detected temperature of the outside air, a predicted resistance value at the time of outside temperature of the secondary battery is calculated, and a first allowable current value is calculated from the predicted resistance value at the time of outside temperature,
The allowable current value of the secondary battery is set when the difference between the second allowable current value at the lowest temperature of the secondary battery and the first allowable current value is equal to or greater than a predetermined threshold value. If the current value is less than the predetermined threshold, the second allowable current value,
The setting of the allowable current value of the secondary battery is the first allowable current value when the temperature difference between the plurality of battery cells is greater than or equal to a predetermined temperature difference, and less than the predetermined temperature difference. A control device for a secondary battery, characterized in that the second allowable current value is used. The secondary battery control device according to any one of claims 2 to 5,
A control apparatus for a secondary battery, wherein an allowable power of the secondary battery is calculated with reference to a relational expression or a data map of a charge state of the secondary battery and an internal resistance value with respect to a temperature of the secondary battery. The secondary battery control device according to any one of claims 2 to 6,
A recording device for recording the cooling rate and temperature change;
A learning device for extracting a relationship between the cooling rate and the temperature of the secondary battery from the recording device;
A control apparatus for a secondary battery, wherein the cooling speed is controlled by sequentially updating a map showing a relationship between the cooling speed and the temperature of the secondary battery. The secondary battery control device according to any one of claims 1 to 7,
When the secondary battery constitutes a plurality of battery units, the cooler is provided for each battery unit, and the cooler is individually controlled for the battery unit. apparatus. The secondary battery control device according to any one of claims 1 to 8,
The first temperature sensor is installed outside a storage box for storing the secondary battery or in the vicinity of an inlet of the cooler,
The second temperature sensor is installed on the surface of the casing of the secondary battery or inside the storage box. A control device for a secondary battery according to any one of claims 1 to 9,
The cooler is configured by a fan, and the cooling speed is changed by controlling the rotational speed of the fan. A control device for a secondary battery according to any one of claims 1 to 9,
The cooler is configured using a heat sink or a heat pipe, and the cooling rate is changed by controlling a refrigerant flow rate of the heat sink or the heat pipe.   A railway vehicle equipped with the secondary battery control device according to any one of claims 1 to 11. Detect the temperature of the outside air that cools the secondary battery and the temperature of multiple locations of the secondary battery,
A secondary battery control method, wherein a cooling rate of the secondary battery is controlled based on a temperature detection signal of the outside air and a temperature detection signal of the secondary battery. A method for controlling a secondary battery according to claim 13, comprising:
The resistance value difference between the first internal resistance value of the secondary battery at the temperature of the outside air and the second internal resistance value of the secondary battery at the temperature of the secondary battery is compared with a predetermined threshold value. ,
A control method for a secondary battery, wherein the cooling rate of the secondary battery is changed depending on whether the resistance value difference is less than a predetermined threshold value or more. The method for controlling a secondary battery according to claim 14,
If less than the predetermined threshold, control the cooling rate to a constant high speed state,
If it is equal to or greater than the predetermined threshold, the cooling rate is gradually increased from a low speed state, and control is performed so as to increase the gradient of the cooling rate from when the resistance value difference becomes less than the predetermined threshold. A control method for a secondary battery, which is characterized. Detect the temperature of the outside air that cools the secondary battery and the voltage, current, and temperature of the secondary battery,
Calculate the state of charge of the secondary battery using the detected value of the secondary battery,
Determining whether the secondary battery needs to be cooled from the detected temperature of the outside air and the temperature of the secondary battery;
If it is determined that the cooling is unnecessary, the cooling device for cooling the secondary battery is stopped,
If it is determined that the cooling is necessary, the secondary internal resistance value of the secondary battery at the temperature of the outside air and the secondary internal resistance value of the secondary battery at the temperature of the secondary battery are determined as the secondary battery. When the battery state of charge is calculated in consideration, the resistance value difference between the first internal resistance value and the second internal resistance value is compared with a predetermined threshold value, and the resistance value difference is less than the predetermined threshold value The cooling device is operated at a constant cooling rate, and when the resistance value difference is equal to or greater than the predetermined threshold, the cooling rate is set to a low state until the temperature of the secondary battery reaches a predetermined temperature, and the secondary A secondary battery control method, comprising: increasing a slope of the cooling rate when a battery temperature exceeds the predetermined temperature. Detect the temperature of the outside air that cools the secondary battery composed of multiple battery cells,
Based on the detected temperature of the outside air, calculate a predicted resistance value at the time of the outside temperature of the secondary battery, calculate a first allowable current value of the secondary battery from the predicted resistance value at the time of the outside temperature,
When the difference between the second allowable current value at the lowest temperature of the secondary battery and the first allowable current value is larger than a predetermined threshold, the time characteristic of the allowable current value of the secondary battery is 2 decreasing the allowable current value of the secondary battery with an inclination from the allowable current value toward the first allowable current value;
Starting cooling of the secondary battery when the allowable current value becomes the first allowable current value;
Maintaining the first allowable current value until the temperature difference between the plurality of battery cells falls within a predetermined temperature difference,
If the temperature difference falls within the predetermined temperature difference, as the time characteristic of the allowable current value of the secondary battery, the second allowable current value is increased by inclining toward the second allowable current value. The secondary battery control method is characterized by maintaining the second allowable current value after reaching the value. A method for controlling a secondary battery according to any one of claims 14 to 17,
A method for controlling a secondary battery, comprising: calculating a permissible power of the secondary battery with reference to a relational expression or a data map of a charge state of the secondary battery and an internal resistance value with respect to a temperature of the secondary battery.

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