JP2012125121A - Charging system and storage battery degradation determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine degradation of a storage battery while reducing space, costs, and human operation.SOLUTION: A charging system 10 comprises a battery pack 1, a charger 2, a temperature measurement part 3, and a degradation determination part 4. The battery pack 1 is constituted by connecting a plurality of electric cells 5 in series. The charger 2 charges the respective electric cells 5 owned by the battery pack 1. The temperature measurement part 3 measures temperature of the plurality of electric cells 5. The degradation determination part 4 monitors the temperature of the plurality of electric cells 5 measured by the temperature measurement part 3, and performs degradation determination processing where it is determined that the electric cell 5 is degraded when the electric cell 5 whose temperature is deviated from the set range containing the average temperature of the plurality of electric cells 5 is detected.

Description

  The present invention relates to a charging system and a storage battery deterioration determination method.

  Conventionally, there is an assembled battery composed of a plurality of storage batteries. For example, the assembled battery is used as a backup power source in a power supply system that converts AC power output from an AC power source into DC power and supplies the load to a load. Such an assembled battery is charged by, for example, a rectifier or a charger.

  Here, when the assembled battery is charged, a charging voltage is applied to each assembled battery, so the magnitude of the voltage applied to each storage battery included in the assembled battery is unknown. If each storage battery is the same, the voltage applied to each is expected to be the same. However, the charging voltage of each storage battery constituting the assembled battery may vary depending on manufacturing variations and operational handling differences. When the variation in the charging voltage becomes significant, the storage battery having a high charging voltage is overcharged, and the storage battery having a low charging voltage becomes insufficiently charged, and in any case, the deterioration of the storage battery is promoted.

  A storage battery that has deteriorated is required to be replaced at an early stage. Therefore, conventionally, various methods for determining the deterioration of the storage battery have been proposed. For example, as a method of measuring the deterioration state of a battery to be measured, a remaining capacity of the battery is determined based on a discharge current that is further connected to the output of a rectifier that supplies power to the load and is discharged to the load and the simulated device. There is a method to calculate. In addition, there is a method in which the deterioration determination device receives an input of discharge condition information of a measurement target battery from a user and calculates a remaining capacity based on a terminal voltage of the measurement target battery connected based on the measurement target battery.

JP 2007-077862 A JP 2006-300561 A

  However, the above-described conventional charging system has a problem that it is not possible to determine the deterioration of the storage battery while reducing space, cost, and human operation. For example, in the method using the pseudo load device, the space and cost due to the installation of the pseudo load device increase. Further, in the method using the deterioration determination device, since the operator needs to perform an operation of connecting the deterioration determination device for each battery to be measured in the field, human operation is large.

  The present invention has been made in view of the above, and an object of the present invention is to provide a charging system and a storage battery deterioration determination method capable of determining deterioration of a storage battery while reducing space, cost, and human operation. And

  In order to solve the above-described problems and achieve the object, a charging system according to the present invention includes an assembled battery configured by connecting a plurality of storage batteries in series, and a charger that charges each storage battery included in the assembled battery. And a temperature measuring unit that measures the temperature of the plurality of storage batteries, and the temperature of the plurality of storage batteries measured by the temperature measuring unit is monitored, and a temperature that deviates from a setting range that includes an average temperature of the plurality of storage batteries. And a deterioration determination unit that performs a deterioration determination process for determining that the storage battery has deteriorated when the storage battery is detected.

  Moreover, the storage battery deterioration determination method according to the present invention is a storage battery deterioration applied to a charging system including an assembled battery configured by connecting a plurality of storage batteries in series and a charger for charging each storage battery included in the assembled battery. A determination method, the step of measuring the temperature of the plurality of storage batteries, the temperature of the measured plurality of storage batteries is monitored, and the storage battery having a temperature that deviates from a set range centering on the average temperature of the plurality of storage batteries And a step of performing a deterioration determination process for determining that the storage battery is deteriorated when the battery is detected.

  According to the present invention, there is an effect that it is possible to determine the deterioration of a storage battery while reducing space, cost, and human operation.

FIG. 1 is a diagram illustrating a configuration example of a charging system according to an embodiment. FIG. 2 is a flowchart illustrating a flow of control by the deterioration determination unit according to the embodiment. FIG. 3 is a flowchart showing the flow of the deterioration determination process shown in FIG.

  Embodiments of a charging system and a storage battery deterioration determination method according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  First, a configuration example of the charging system according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration example of a charging system according to the present embodiment. As illustrated in FIG. 1, the charging system 10 according to the present embodiment includes an assembled battery 1, a charger 2, a temperature measurement unit 3, and a deterioration determination unit 4.

  The assembled battery 1 is configured by connecting a plurality of unit cells 5 in series. In this embodiment, the assembled battery 1 is configured by connecting 12 unit cells 5 in series. In this embodiment, the single battery 5 is a lithium ion having a full charge voltage of 4.1 [V (volts)], a rated voltage of 4.0 [V], and a rated capacity of 200 [Ah (ampere hour)]. A storage battery is used. Therefore, in the present embodiment, the fully charged voltage of the assembled battery 1 is 49.2 [V], the rated voltage is 48.0 [V], and the rated capacity is 200 [Ah].

  The charger 2 charges each cell 5 included in the assembled battery 1. In the charger 2, the output voltage is set to a voltage setting value obtained by the product of the full charge voltage of the single cells 5 and the number of the single cells 5. In the present embodiment, the output voltage of the charger 2 is set to 49.2 [V] obtained by the product of the full charge voltage 4.1 [V] of the unit cells 5 and the number of series units 12 of the unit cells 5. The maximum output current of the charger 2 is set to 20 [A (ampere)].

  Immediately after charging of the battery pack 1 by the charger 2, the voltage of the battery pack 1 is low at the beginning of charging, so that the output voltage of the battery charger 2 drops and matches the voltage of the battery pack 1. Thereafter, the assembled battery 1 is charged with a constant current, and the voltage of the assembled battery 1 rises as charging progresses (constant current charging). When the voltage of the assembled battery 1 reaches the full charge voltage, the charging current starts to decrease. Thereafter, charging of the assembled battery 1 is continued at a constant voltage (constant voltage charging).

  The temperature measuring unit 3 measures the temperatures of the plurality of single cells 5 included in the assembled battery 1. In the present embodiment, the same number of temperature measuring units 3 as the number of unit cells 5 are provided. Each temperature measurement unit 3 is connected to each of the plurality of single cells 5 included in the assembled battery 1, measures the temperature of each single cell 5, and notifies the deterioration determination unit 4.

  When the deterioration determination unit 4 monitors the temperature of the plurality of single cells 5 measured by the temperature measurement unit 3 and detects a storage battery having a temperature that deviates from the set range including the average temperature of the plurality of single cells 5, A deterioration determination process for determining that the unit cell 5 has deteriorated is performed.

  Specifically, the deterioration determination unit 4 acquires the temperature of each unit cell 5 from each of the plurality of temperature measurement units 3 and calculates the average temperature of the plurality of unit cells 5. Moreover, the deterioration determination part 4 calculates the setting range containing the calculated average temperature. For example, the deterioration determination unit 4 sets a setting range having a certain width above and below the average temperature. In the present embodiment, the deterioration determination unit 4 sets a range of ± 5 [° C.] from the average temperature as the setting range. Moreover, the deterioration determination part 4 determines whether there exists the single cell 5 of the temperature which deviates from a setting range among the several single cells 5 which the assembled battery 1 has. And the deterioration determination part 4 determines with the single cell 5 having deteriorated, when there exists the single cell 5 of the temperature which deviates from a setting range.

  For example, at a certain point in time, the temperature of 12 unit cells 5 is 22.0 [° C.], 23.2 [° C.], 24.1 [° C.], 21.8 [° C.], and 25.4 [° C.], respectively. 22.6 [° C], 24.1 [° C], 23.3 [° C], 23.1 [° C], 21.7 [° C], 22.0 [° C], 23.1 [° C] Suppose there was.

  In this case, the deterioration determination unit 4 calculates the average temperature as 23.0 [° C.]. At this time, the most deviating from the average temperature is the single cell 5 having a temperature of 25.4 [° C.], and the deviation of the temperature of the single cell 5 from the average temperature is 2.4 [° C.]. It is. That is, at this time, the temperature of all the unit cells 5 is within the set range of the average temperature ± 5 [° C.]. Therefore, at this time, the deterioration determination unit 4 does not determine that any single cell 5 is deteriorated.

  At another time point, for example, the temperature of the 12 unit cells 5 is 22.0 [° C.], 23.2 [° C.], 24.1 [° C.], 21.8 [° C.], and 28.4, respectively. [° C], 22.6 [° C], 24.1 [° C], 23.3 [° C], 23.1 [° C], 21.7 [° C], 22.0 [° C], 23.1 [° C] [° C.].

  In this case, the deterioration determination unit 4 calculates the average temperature as 23.3 [° C.]. At this time, the most deviating from the average temperature is the unit cell 5 having a temperature of 28.4 [° C.], and the deviation of the temperature of the unit cell 5 from the average temperature is 5.1 [° C.]. It is. That is, at this time, the unit cell 5 having this temperature of 28.4 [° C.] deviates from the setting range of the average temperature ± 5 [° C.]. Therefore, at this time, the deterioration determination unit 4 determines that the unit cell 5 having this temperature of 28.4 [° C.] has deteriorated.

  Next, control by the deterioration determination unit 4 according to the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart illustrating a flow of control by the deterioration determination unit 4 according to the present embodiment. For example, the deterioration determination unit 4 performs the control described below at a predetermined cycle.

  As shown in FIG. 2, first, the deterioration determination unit 4 determines whether or not the output voltage of the charger 2 is a voltage set value and whether or not the output current of the charger 2 is equal to or less than a predetermined current threshold. Determination is made (step S11).

  As described above, the voltage setting value is a voltage value obtained by the product of the full charge voltage of the unit cells 5 and the number of the unit cells 5. The predetermined current threshold is set to a current value lower than a constant current while the charger 2 is drooping. That is, the state where the output voltage of the charger 2 is at the voltage set value or the state where the output current of the charger 2 is equal to or less than a predetermined current threshold indicates a state where the drooping of the charger 2 is stopped. . That is, the deterioration determination unit 4 determines whether or not the drooping of the charger 2 is stopped by performing the determination in step S11.

  Then, when the output voltage of the charger 2 is equal to or lower than the voltage set value, or the output current of the charger 2 is equal to or lower than a predetermined current threshold (Yes in step S11), the deterioration determination unit 4 A deterioration determination process for determining the deterioration of the battery 5 is performed (step S12). Subsequently, the deterioration determination unit 4 determines whether or not there is a single cell 5 determined to be deteriorated as a result of performing the deterioration determination process (step S13).

  And when there exists the cell 5 determined with having deteriorated (step S13, Yes), the deterioration determination part 4 is controlled to stop the charge by the charger 2 (step S14). For example, the deterioration determination unit 4 transmits a control signal instructing the charger 2 to stop charging. Moreover, when there exists the single battery 5 determined to be deteriorated (step S13, Yes), the deterioration determination part 4 is controlled to issue an alarm (step S15). For example, the deterioration determination unit 4 transmits an external signal instructing to issue an alarm to an alarm device provided outside the charging system 10.

  On the other hand, when there is no single battery 5 determined to be deteriorated (step S13, No), the deterioration determination unit 4 ends the process.

  Next, the deterioration determination process shown in FIG. 2 will be described with reference to FIG. FIG. 3 is a flowchart showing the flow of the deterioration determination process shown in FIG. As shown in FIG. 3, first, the deterioration determination unit 4 acquires the temperature of each unit cell 5 from each of the plurality of temperature measurement units 3 (step S <b> 21). And the degradation determination part 4 calculates the average value of the acquired temperature (step S22).

  Subsequently, the deterioration determination unit 4 determines whether or not there is a single cell 5 that deviates from a certain range from the calculated average value (step S23). Here, when there is no unit cell 5 that deviates from the certain range (step S23, No), the deterioration determination unit 4 repeats this determination until the unit cell 5 that deviates from the certain range is detected.

  Then, when there is a single cell 5 that deviates from a certain range from the average value (step S23, Yes), the deterioration determination unit 4 determines that the single cell 5 is deteriorated (step S24). On the other hand, when there is no unit cell 5 that deviates from a certain range from the average value (step S23, No), the deterioration determination unit 4 does not determine that any unit cell 5 is deteriorated.

  As described above, the charging system 10 according to the present embodiment includes the assembled battery 1, the charger 2, the temperature measurement unit 3, and the deterioration determination unit 4. The assembled battery 1 is configured by connecting a plurality of unit cells 5 in series. The charger 2 charges each cell 5 included in the assembled battery 1. The temperature measurement unit 3 measures the temperatures of the plurality of single cells 5. The deterioration determination unit 4 monitors the temperature of the plurality of single cells 5 measured by the temperature measurement unit 3 and detects the single cell 5 having a temperature that deviates from the set range including the average temperature of the plurality of single cells 5. Then, a deterioration determination process for determining that the unit cell 5 has deteriorated is performed.

  As described above, in this embodiment, since the determination of deterioration is performed based on the temperature of each unit cell 5, only the temperature detection unit is required as an additional element. Therefore, it is possible to reduce the space and cost of the degradation determination apparatus. Further, when the temperature of the unit cell 5 deviates from a certain range from the average value, the deterioration of the unit cell 5 is automatically determined, so that the human operation can be reduced. Thus, according to the present embodiment, it is possible to determine the deterioration of the storage battery while reducing space, cost, and human operation. Further, when an assembled battery connected to the power supply system is used as a backup power source, it is possible to determine the deterioration of the single cell without reducing the backup capability.

  In the present embodiment, the output voltage of the charger 2 is set to a voltage setting value obtained by the product of the full charge voltage of the single cells 5 and the number of the single cells 5. When the output voltage is equal to or lower than a predetermined voltage threshold value, the deterioration determination process is performed. In the present embodiment, the deterioration determination unit 4 performs the deterioration determination process when the output current of the charger 2 is equal to or less than a predetermined current threshold. Therefore, according to the present embodiment, since the deterioration determination of the unit cell 5 is performed when the drooping of the charger 2 is stopped, the deterioration determination can be performed more accurately.

  In the present embodiment, the deterioration determination unit 4 controls to stop the charging by the charger 2 when there is a single cell 5 determined to be deteriorated as a result of performing the deterioration determination process. Therefore, according to the present embodiment, when the deteriorated unit cell 5 is detected, the charging of the assembled battery 1 can be automatically stopped.

  Further, in this embodiment, the deterioration determination unit 4 controls to issue an alarm when there is a single cell 5 that is determined to be deteriorated as a result of performing the deterioration determination process. Therefore, according to this embodiment, when a deteriorated unit cell 5 is detected, it is possible to notify the user to that effect. Thereby, for example, it becomes possible to prompt the user to replace or check the deteriorated unit cell 5.

  In addition, in the present Example, although the example in case a lithium ion storage battery is used as the cell 5 was shown, this invention is not limited to this. For example, even when another secondary battery is used as the single battery 5, the present invention can be similarly applied.

DESCRIPTION OF SYMBOLS 10 Charging system 1 Assembly battery 2 Charger 3 Temperature measurement part 4 Degradation determination part 5 Single battery

Claims (6)

An assembled battery configured by connecting a plurality of storage batteries in series;
A charger for charging each storage battery of the assembled battery;
A temperature measuring unit for measuring the temperatures of the plurality of storage batteries;
The temperature of the plurality of storage batteries measured by the temperature measurement unit is monitored, and when a storage battery having a temperature that deviates from a setting range including an average temperature of the plurality of storage batteries is detected, it is determined that the storage battery is deteriorated. And a deterioration determination unit that performs a deterioration determination process. The output voltage of the charger is set to a voltage setting value obtained by the product of the full charge voltage of the storage battery and the number of the storage batteries,
The charging system according to claim 1, wherein the deterioration determination unit performs the deterioration determination process when the output voltage of the charger is the voltage setting value.   The charging system according to claim 1, wherein the deterioration determination unit performs the deterioration determination process when an output current of the charger is equal to or less than a predetermined current threshold.   The deterioration determination unit controls to stop charging by the charger when there is a storage battery determined to be deteriorated as a result of performing the deterioration determination process. The charging system according to 2 or 3.   The deterioration determination unit controls to issue an alarm when there is a storage battery that has been determined to be deteriorated as a result of performing the deterioration determination process. The charging system according to one. A storage battery deterioration determination method applied to a charging system having an assembled battery configured by connecting a plurality of storage batteries in series and a charger for charging each storage battery included in the assembled battery,
Measuring the temperature of the plurality of storage batteries;
A deterioration determination that monitors the measured temperature of the plurality of storage batteries and determines that the storage battery has deteriorated when a storage battery having a temperature that deviates from a setting range centered on an average temperature of the plurality of storage batteries is detected. A method for determining deterioration of a storage battery, comprising: performing a process.

Images