JP2015109148A - Contact failure detection device, battery control system, contact failure detection method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact failure detection device capable of detecting the occurrence of arc discharge in a battery cell.SOLUTION: A contact failure detection device comprises a whole voltage acquisition unit, an individual voltage acquisition unit and a contact failure determination unit. The whole voltage acquisition unit acquires the voltage of the whole secondary battery module. The individual voltage acquisition unit acquires the voltage of each of a plurality of battery cells provided in the secondary battery module. The contact failure determination unit determines the occurrence of contact failure at the connection part of the battery cell on the basis of a difference between the sum total of the voltage acquired by the individual voltage acquisition unit and the voltage acquired by the whole voltage acquisition unit and a threshold determined based on the physical quantity indicating the characteristics of the arc discharge inside the secondary battery module.

Description

  The present invention relates to a contact failure detection device, a battery management system, a contact failure detection method, and a program.

Secondary battery modules are used in various fields such as hybrid cars and aircraft from the viewpoint of effective use of energy. A technique for predicting an abnormality such as ignition in the secondary battery module is important.
Patent Document 1 describes a technique for detecting an abnormality in a secondary battery as a related technique.

Japanese Patent No. 4696291

By the way, in a secondary battery module, a plurality of battery cells are often connected to each other by a bus bar. When a contact failure occurs between the electrode terminal of the battery cell and the bus bar in the secondary battery module, the output voltage of the secondary battery module decreases or heat is generated due to an increase in arc discharge or contact resistance.
Therefore, there has been a demand for a technique that can detect the occurrence of arc discharge in the battery cell.

  Therefore, an object of the present invention is to provide a contact failure detection device, a battery management system, a contact failure detection method, and a program that can solve the above-described problems.

  In order to achieve the above object, according to one aspect of the present invention, a contact failure detection device includes an overall voltage acquisition unit, an individual voltage acquisition unit, and a contact failure determination unit. The overall voltage acquisition unit acquires the overall voltage of the secondary battery module. The individual voltage acquisition unit acquires voltages of a plurality of battery cells included in the secondary battery module. The contact failure determination unit is based on a difference between a total voltage acquired by the individual voltage acquisition unit and a voltage acquired by the overall voltage acquisition unit, and a physical quantity indicating characteristics of arc discharge inside the secondary battery module. On the basis of the threshold value determined in this step, it is determined that a contact failure has occurred in the connection portion of the battery cell.

  Further, according to another aspect of the present invention, the contact failure determination unit provided in the contact failure detection device may change the state of the contact failure portion when the arc discharge occurs as a physical quantity indicating the characteristics of arc discharge. When the abnormality determination threshold value determined based on the voltage corresponding to the maximum error voltage that may be included in the voltage acquired by the overall voltage acquisition unit and the individual voltage acquisition unit is exceeded. It is determined that a contact failure has occurred in the cell connection.

  Moreover, according to another aspect of the present invention, the contact failure determination unit provided in the contact failure detection device is connected in parallel with a series of a plurality of secondary battery modules connected in series as a physical quantity indicating the characteristics of arc discharge. Detect currents flowing through battery cells in multiple columns, compare the detected currents in each column, classify them into sets for each predetermined current range, and set other than the set with the largest number of columns in each classified set It is determined that an abnormal current flows through the battery cells in the row and a contact failure occurs in the connection portion of the battery cells.

  According to another aspect of the present invention, the contact failure determination unit included in the contact failure detection device may be configured such that the physical difference indicating the characteristics of arc discharge is a voltage difference between columns in which a plurality of secondary battery modules are connected in series. Current is detected, and it is determined that a contact failure has occurred in the connection portion of the battery cells when the voltage difference in each column and the time-series waveform of the current match the arc discharge pattern waveform.

  According to another aspect of the present invention, the contact failure determination unit included in the contact failure detection device detects heat generated when arc discharge occurs using a temperature sensor, and contact failure occurs in a connection portion of the battery cell. Determine that it has occurred.

  According to another aspect of the present invention, the contact failure determination unit included in the contact failure detection device detects light at the time of arc discharge using an illuminance sensor, and there is a contact failure at a connection portion of the battery cell. Determine that it has occurred.

  According to another aspect of the present invention, the contact failure determination unit provided in the contact failure detection device detects a sound at the time of arc discharge using a microphone, and contact failure occurs in a connection portion of the battery cell. It is determined that

  According to another aspect of the present invention, a battery management system includes the contact failure detection device.

  According to another aspect of the present invention, the contact failure detection method acquires the voltage of the entire secondary battery module, acquires the voltage of each of the plurality of battery cells included in the secondary battery module, and acquires the acquired voltage. Based on the difference between the total voltage and the acquired voltage, and a threshold value determined based on a physical quantity indicating the characteristics of arc discharge inside the secondary battery module, there is a contact failure in the connection portion of the battery cell. Determine that it has occurred.

  According to another aspect of the present invention, the program includes a computer of the contact failure detection device, a whole voltage obtaining unit that obtains a whole voltage of the secondary battery module, and a plurality of battery cells provided in the secondary battery module. Individual voltage acquisition means for acquiring the respective voltages, the difference between the total voltage acquired by the individual voltage acquisition means and the voltage acquired by the overall voltage acquisition means, and the arc discharge inside the secondary battery module A program that functions as a contact failure determination unit that determines that a contact failure has occurred in a connection portion of the battery cell based on a threshold value determined based on a physical quantity indicating a feature.

  According to the charge control device according to the embodiment of the present invention, it is possible to detect the occurrence of arc discharge in the battery cell.

It is a figure which shows an example of a structure of the battery management system 1 provided with the contact failure detection apparatus 10 by 1st embodiment of this invention. It is a figure which shows an example of the change of the voltage difference of the DC terminal voltage Vpack of the charging / discharging apparatus 60 at the time of arc discharge generating, and the cell voltage Vcell of each battery cell. It is a figure which shows an example of the voltage between the progress of the poor contact between two metals which are in contact, and a poor contact point. It is a figure which shows an example of the processing flow of the battery management system 1 provided with the contact failure detection apparatus 10 by 1st embodiment of this invention. It is a figure which shows the example of the secondary battery module 30 which the contact failure detection apparatus 10 with which the battery management system 1 by 2nd embodiment of this invention is provided makes a contact failure detection target. It is a figure which shows an example which detects generation | occurrence | production of arc discharge with the thermistor which is a temperature sensor.

<First embodiment>
FIG. 1 is a diagram illustrating an example of a configuration of a battery management system 1 including a contact failure detection device 10 according to a first embodiment of the present invention.
As shown in FIG. 1, the battery management system 1 according to the first embodiment includes a contact failure detection device 10, an output unit 20, secondary battery modules 30 (30a, 30b,...), And a battery control circuit. 40, a host controller 50, a charge / discharge device 60, a load 70, and a storage unit 80.

The contact failure detection device 10 includes an overall voltage acquisition unit 101, an individual voltage acquisition unit 102, and a contact failure determination unit 103.
The overall voltage acquisition unit 101 included in the contact failure detection device 10 acquires the voltage of the entire secondary battery module 30. The total voltage acquisition unit 101 outputs the acquired voltage of the entire secondary battery module 30 to the contact failure determination unit 103.
The individual voltage acquisition unit 102 acquires each voltage of the plurality of battery cells. The individual voltage acquisition unit 102 outputs the acquired voltages of the plurality of battery cells to the contact failure determination unit 103.
The contact failure determination unit 103 is connected when the difference between the total voltage acquired by the individual voltage acquisition unit 102 and the voltage acquired by the overall voltage acquisition unit 101 is equal to or greater than a predetermined threshold value indicating the characteristics of arc discharge. It is determined that the contact failure of the part has occurred.

The output unit 20 includes a display unit 201, a speaker 202, and a vibration unit 203.
The display unit 201 displays visual information based on the alarm signal input from the contact failure determination unit 103.
The speaker 202 outputs sound information based on the alarm signal input from the poor contact determination unit 103.
The vibration unit 203 outputs vibration information based on the alarm signal input from the contact failure determination unit 103.

The secondary battery module 30a includes a module battery 301a that constitutes an assembly of a plurality of battery cells, and a battery monitoring circuit 302a that measures the cell voltage of each battery cell. Similarly, the secondary battery module 30b includes a module battery 301b that is an assembly of a plurality of battery cells, and a battery monitoring circuit 302b that measures the cell voltage of each battery cell. The secondary battery module 30 is a general term for the secondary battery modules 30a, 30b,.
Each of the battery monitoring circuits 302 included in the secondary battery module 30 outputs the measured cell voltage to the individual voltage acquisition unit 102.
The battery control circuit 40 controls the secondary battery module 30 based on the control performed by the host control device 50.

The host control device 50 controls the battery control circuit 40 and the charge / discharge device 60.
The charging / discharging device 60 charges and discharges power to and from the load 70 and the secondary battery module 30 based on the control performed by the host control device 50.
The load 70 is a load in the battery management system 1. For example, when the battery management system 1 is a building, the load 70 is an elevator, an escalator, lighting, or the like.
The storage unit 80 stores various data such as threshold values required when the contact failure determination unit 103 determines contact failure of a connection portion.

Next, prevention of erroneous detection when the contact failure detection device 10 according to the first embodiment detects an abnormality of the secondary battery module 30 will be described.
Here, it is assumed that the battery management system 1 is a system that outputs a voltage of 800 volts. In addition, the number of battery cells in the secondary battery module 30 is 250. However, the battery management system 1 is not limited to 800 volts. The number of battery cells is not limited to 250.

The charging / discharging device 60 in the battery management system 1 according to the first embodiment measures Vpack which is a DC terminal voltage of the charging / discharging device 60. It is assumed that the measurement accuracy with which the charge / discharge device 60 measures Vpack is about ± 2 volts.
Further, the battery monitoring circuit 302 measures the cell voltage Vcell of each battery cell in the module battery 301. It is assumed that the measurement accuracy with which the battery monitoring circuit 302 measures Vcell is about ± 4 millivolts. In this case, the maximum error included in the measurement results of the charge / discharge device 60 and the battery monitoring circuit 302 is 2 volts + 4 millivolts × 250 (number of battery cells) = 3 volts. Here, it is assumed that an error of 4.5 volts occurs in a measurement error with a margin of about 50%.

  The abnormality determination threshold value used for determination by the contact failure detection device 10 is false detection with a maximum error of 4.5 volts included in the total of the measured DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell. To avoid this, it must be set higher than 4.5 volts. Moreover, the abnormality determination threshold value used for determination by the contact failure detection device 10 is −4.5 of the maximum error on the lower limit side included in the measured DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell. It must be set lower than the voltage at which arcing occurs from the volt.

FIG. 2 is a diagram illustrating an example of a change in voltage difference between the DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell when arc discharge occurs.
As shown in FIG. 2, loosening occurs between the electrode terminals of the battery cells and the bus bar, and arc discharge occurs. Then, the voltage difference between the DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell changes from approximately 0 volts to 24 volts. In addition, the numerical example shown here is only an example, and is not limited to these values.
FIG. 3 is a diagram illustrating an example of the progress of contact failure between two metals in contact and the voltage between contact failure points.
Next, with reference to FIG. 3, setting of a threshold value for the contact failure determination unit 103 included in the contact failure detection device 10 to detect arc discharge generated in the secondary battery module 30 will be described.

  As shown on the left side in FIG. 3, at the time of static contact at the initial stage of poor contact, there are many contacts between two metals, the contact area is wide, and the contact resistance is relatively low (state I). Next, the separation starts, the number of contact points decreases, and the contact resistance increases (state II). In this state, the flowing current is the same, so that current concentration occurs and separation proceeds (state III). In this state, the contact is in the metal phase, and the voltage generated at the contact is approximately 12 volts. Then, when the separation continues, arc discharge occurs (state IV). Due to the occurrence of this arc discharge, the contact changes from the metal phase to the gas phase. In this experimental example, as shown on the right side in FIG. 3, when arc discharge occurs, the voltage generated at the contact is about 24 volts. That is, when arc discharge occurs between the electrode terminal of the battery cell and the bus bar, the voltage between the electrode terminal of the battery cell and the bus bar changes from 0 volts to 24 volts. Thus, the state changes from the state I to the state IV with the passage of time.

  Therefore, the contact failure detection apparatus 10 sets the voltage 15 volts shown in FIG. 2 described above as the abnormality determination threshold value, for example. The abnormality determination threshold value 15 volts used for the determination by the contact failure detection device 10 is false detection with a maximum error of 4.5 volts included in the measured DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell. Satisfying the requirement that it must be higher than 4.5 volts in order to avoid this. Further, the abnormality determination threshold value 15 volts used for determination by the contact failure detection device 10 is -4.5 volts, which is the maximum error included in the measured DC terminal voltage Vpack of the charging / discharging device 60 and the cell voltage Vcell of each battery cell. From this, the condition that it must be lower than the voltage (24 volts-4.5 volts) when arc discharge occurs is satisfied. Thus, the occurrence of arc discharge can be detected.

  In addition, when the threshold value setting shown in FIG. 2 and FIG. 3 is generalized, the battery management system 1 including the contact failure detection device 10 according to the first embodiment is expressed as (Vpack− (total Vcell)). ) Is larger than a threshold value for abnormality determination (hereinafter referred to as abnormality determination threshold value) set to be equal to or greater than an error in measurement, it is determined that some abnormality has occurred. Then, the battery management system 1 performs measures such as notification of abnormality in the battery cell and protection operation of the secondary battery module 30 and the peripheral devices of the secondary battery module 30.

FIG. 4 is a diagram illustrating an example of a processing flow of the battery management system 1 including the contact failure detection device 10 according to the first embodiment of the present invention.
Next, the processing flow of the battery management system 1 according to the first embodiment will be described with reference to FIG.
The process performed by the battery management system 1 according to the first embodiment illustrated in FIG. 4 is performed by the contact failure determination unit 103 included in the contact failure detection device 10 of the battery management system 1 illustrated in FIG. 1 (Vpack− (total Vcell)). ) Is output when it is determined that the absolute value of () is larger than the abnormality determination threshold value.

First, the overall voltage acquisition unit 101 included in the contact failure detection device 10 acquires a measured value of the DC terminal voltage Vpack of the charge / discharge device 60 from the charge / discharge device 60 (step S1). Then, the overall voltage acquisition unit 101 outputs the acquired measured value of the DC terminal voltage Vpack of the charging / discharging device 60 to the contact failure determination unit 103.
Moreover, the individual voltage acquisition part 102 acquires the measured value of the cell voltage Vcell of each cell in the module battery 301 (step S2). Then, the individual voltage acquisition unit 102 outputs the acquired measured value of the cell voltage Vcell of each cell in the module battery 301 to the contact failure determination unit 103.

The contact failure determination unit 103 inputs a measured value of the DC terminal voltage Vpack of the charging / discharging device 60 from the overall voltage acquisition unit 101. Further, the contact failure determination unit 103 inputs a measured value of the cell voltage Vcell of each cell in the module battery 301 from the individual voltage acquisition unit 102.
Then, the poor contact determination unit 103 determines whether or not the absolute value of (Vpack− (total Vcell)) is larger than the abnormality determination threshold value (step S3).
When the contact failure determination unit 103 determines that the absolute value of (Vpack− (total Vcell)) is smaller than or equal to the abnormality determination threshold value (NO in step S3), the contact failure determination unit 103 determines that the Is determined not to occur, and the process returns to step S1.
Further, when the contact failure determination unit 103 determines that the absolute value of (Vpack− (total Vcell)) is larger than the abnormality determination threshold value (step S3, YES), the contact failure determination unit 103 has an abnormality. It determines with having performed, and while outputting an alarm signal to the output part 20, the protection operation signal for stopping operation | movement of the charging / discharging apparatus 60 or the secondary battery module 30 is output to the high-order control apparatus 50 (step S4). .

When the output unit 20 receives an alarm signal from the poor contact determination unit 103, each of the display unit 201, the speaker 202, and the vibration unit 203 included in the output unit 20 outputs an alarm corresponding to the alarm signal (step S5).
The display unit 201 displays visual information based on the alarm signal input from the contact failure determination unit 103. The display unit 201 is, for example, a liquid crystal panel, and displays a letter “abnormal voltage detected”.

The speaker 202 outputs sound information based on the alarm signal input from the poor contact determination unit 103. The speaker 202 outputs a synthetic voice that is artificially created, for example, “abnormal voltage detected”.
The vibration unit 203 outputs vibration information based on the alarm signal input from the contact failure determination unit 103. The vibration unit 203 includes a vibrator and vibrates.
Note that the alarm output by the output unit 20 may be any one or a plurality of combinations of any one.
Further, when the host controller 50 receives the protection operation signal from the contact failure determination unit 103, the host controller 50 performs control to stop the operation of peripheral devices such as the charge / discharge device 60 and the secondary battery module 30 (step S6).

Heretofore, the contact failure detection device 10 according to the first embodiment of the present invention and the battery management system 1 including the contact failure detection device 10 have been described.
The contact failure detection apparatus 10 according to the embodiment of the present invention includes an overall voltage acquisition unit 101, an individual voltage acquisition unit 102, and a contact failure determination unit 103. The contact failure determination unit 103 acquires, as a physical quantity indicating the characteristics of arc discharge, the voltage according to the change in the state of the contact failure part when the arc discharge occurs, and the overall voltage acquisition unit 101 and the individual voltage acquisition unit 102 When the abnormality determination threshold value determined based on the maximum error voltage that may be included in the measured voltage is exceeded, it is determined that a contact failure has occurred in the connection portion of the battery cell.
If it does in this way, generation | occurrence | production of arc discharge can be detected in a battery cell.

<Second Embodiment>
FIG. 5 is a diagram illustrating an example of the secondary battery module 30 that is detected by the contact failure detection device 10 included in the battery management system 1 according to the second embodiment of the present invention as a contact failure detection target.
Next, detection of occurrence of arc discharge of the secondary battery module 30 in the battery management system 1 by the contact failure determination unit 103 according to the second embodiment will be described with reference to FIG.

In the battery management system 1 according to the second embodiment, instead of the secondary battery module 30 according to the first embodiment, as shown in FIG. 5, each row in which a plurality of secondary battery modules are connected in series is arranged in parallel. A connected secondary battery module 30 is provided.
The contact failure detection device 10 performs the same determination on the secondary battery module 30 according to the second embodiment as the contact failure detection device 10 according to the first embodiment for each column, thereby generating arc discharge. Can be detected.

In addition, substantially the same current flows through the battery cells in each row in the secondary battery module 30 according to the second embodiment. However, when arc discharge occurs in the battery cells in the row, the current flowing through the battery cells in the row in which the arc discharge occurs greatly changes.
Therefore, for example, the contact failure detection apparatus 10 compares the average current of all the columns in the secondary battery module 30 according to the second embodiment with the average current of each column, and classifies them into a set for each predetermined current range ( Step S301). For example, in the secondary battery module 30, it is assumed that there are five columns from column 1 to column 5. And if the average current in each column is column 1: 301 amp, column 2: 295 amp, column 3: 302 amp, column 4: 305 amp, column 5: 297 amp, the total average value is 300 amps is there. And when classifying into a set for every 5 amperes as a predetermined current range from the average value, the contact failure detection device 10 has set A (295 amperes to 300 amperes): column 2 and column 5, set B (300 amperes to 305). Ampere): Column 1, Column 3, and Column 4.

The contact failure detection apparatus 10 determines that the set having the largest number of columns in each set is a set of columns in which normal current flows (step S302). In the example in which there are five columns from column 1 to column 5 described above, the contact failure detection apparatus 10 is normal because the number of columns in the set A is 2 and the number of columns in the set B is 3. The set through which current flows is determined to be set B.
In this case, the process of step S301 and step S302 is performed following the process of step S3 performed by the contact failure detection device 10 according to the first embodiment.
In this way, the contact failure detection device 10 can identify the row where the occurrence of arc discharge has occurred. In this case, the host controller 50 may input the protection operation signal from the contact failure determination unit 103 and control the battery control circuit 40 so as to open a column indicating the occurrence of arc discharge.

  In addition, the contact failure detection device 10 determines whether the voltage difference of each column and the time series waveform of the current in the secondary battery module 30 according to the second embodiment match the arc discharge pattern. A column indicating occurrence may be specified. For example, the time series waveform of the voltage difference of each column is a waveform as shown in FIG. The contact failure detection device 10 may measure the voltage difference and current time-series waveform of each column as shown in FIG. 2 and compare it with the arc discharge pattern acquired in advance through experiments or the like.

Heretofore, the contact failure detection device 10 according to the first embodiment of the present invention and the battery management system 1 including the contact failure detection device 10 have been described.
The contact failure determination unit 103 included in the contact failure detection apparatus 10 according to the embodiment of the present invention includes a voltage corresponding to a change in the state of the contact failure portion when arc discharge, which is a physical quantity indicating the characteristics of arc discharge, If the abnormality determination threshold determined based on the maximum error voltage that may be included in the voltage acquired by the voltage acquisition unit 101 and the individual voltage acquisition unit 102 is exceeded, contact failure in the connection portion of the battery cell Is determined to have occurred.

  In addition, the contact failure determination unit 103 included in the contact failure detection device 10 according to the embodiment of the present invention includes a plurality of columns in which a plurality of secondary battery modules 30 are connected in series as a physical quantity indicating the characteristics of arc discharge. The current flowing in the battery cells in the column of the current is detected, the currents of the detected columns are compared, and the currents are classified into sets for each predetermined current range. It is determined that an abnormal current flows through the battery cell and a contact failure occurs at the connection portion of the battery cell.

In addition, the contact failure determination unit 103 included in the contact failure detection apparatus 10 according to the embodiment of the present invention is configured such that the voltage difference and current of each column in which a plurality of secondary battery modules 30 are connected in series are used as physical quantities indicating the characteristics of arc discharge. Is detected, and it is determined that a contact failure has occurred in the connection portion of the battery cells when the time-series waveform of the voltage difference and current in each column coincides with the arc discharge pattern waveform.
If it does in this way, generation | occurrence | production of arc discharge can be detected in the battery cell of each row | line | column with which the some secondary battery module 30 was connected in series.

<Third embodiment>
The battery management system 1 including the contact failure detection device 10 according to the third embodiment of the present invention has a configuration in which a temperature sensor is added to the battery management system 1 of the first embodiment. The contact failure detection device 10 detects arc discharge that generates a low voltage difference, for example, a voltage difference of 5 volts, using a temperature sensor such as a thermistor.
When the arc voltage is about 9 volts, the difference between plus and minus maximum measurement error 4.5 volts = 9 volts shown in the first embodiment is buried, and the contact failure detection device 10 may not detect the arc voltage. .
When the contact failure detection device 10 detects the occurrence of arc discharge using a temperature sensor, the temperature detection is delayed, the separator inside the battery melts, and the battery may run out of heat.
Therefore, in addition to the detection using the abnormal voltage threshold shown in the first embodiment, the contact failure detection device 10 performs detection by the temperature sensor in parallel, and in the region where the arc voltage is low, detection by the temperature sensor, Detection is performed by temperature in a region where the arc voltage is high.

Next, processing of the contact failure detection apparatus 10 using a temperature sensor will be described.
It is assumed that arc discharge that causes a low voltage difference occurs between the electrode terminal of the battery cell and the bus bar in the secondary battery module 30 according to the third embodiment. In this case, heat is generated due to an increase in contact resistance at the point of contact failure.

The temperature sensor detects this heat. The contact failure determination unit 103 provided in the contact failure detection device 10 is sufficient compared to the time until the arc discharge is derived and the separator is melted or the time from the current temperature to the temperature set as the threshold value. The temperature information indicated by the temperature sensor is acquired at short time intervals (step S303). And the poor contact determination part 103 compares the acquired temperature information with the preset temperature threshold value, and determines whether the acquired temperature information exceeded the temperature threshold value (step S304). If the contact failure determination unit 103 determines that the acquired temperature information has exceeded a preset temperature threshold value, the contact failure determination unit 103 outputs a signal for battery protection to the host controller 50 (step S305).
In this case, the processing from step S303 to step S305 is performed in parallel with the processing of step S3 performed by the contact failure detection device 10 according to the first embodiment.

FIG. 6 is a diagram illustrating an example in which the occurrence of arc discharge is detected by a thermistor that is a temperature sensor.
Next, an example in which the contact failure determination unit 103 according to the third embodiment detects arc discharge that causes a low voltage difference in the battery management system 1 using a thermistor that is a temperature sensor will be described with reference to FIG.
As shown in the frame in the graph of FIG. 6, when the contact failure detection device 10 detects the occurrence of arc discharge using a thermistor, the temperature at the installation position of the thermistor and the temperature of the terminal that is the object to be measured are different. Therefore, it is necessary to determine the detection threshold in consideration of the relative temperature difference between the temperature at the thermistor installation position and the temperature at the position of the object to be measured, and the delay time associated with the thermistor temperature detection time. There is.

In the example shown in FIG. 6, the object to be measured is a negative electrode, and when the negative electrode reaches 140 degrees, the separator starts to melt, and thermal runaway may occur.
Therefore, it is necessary to take measures to suppress the temperature rise before the start of melting of the separator. In the battery management system 1, a protection operation such as disconnection of the battery is performed when the negative electrode reaches 100 degrees. In other words, it is necessary to detect arc discharge 1.8 seconds before the melting timing of the separator and perform a protective operation. Therefore, in this example shown in FIG. 6, the temperature detection threshold value at the installation position of the thermistor is set to 60 degrees (the negative electrode is about 42 degrees), and the arc discharge is performed in about 0.9 seconds after the arc discharge occurs. It can be detected.
The threshold value for detecting the temperature rise due to the occurrence of arc discharge using the temperature sensor is determined through experiments and simulations for various conditions such as the position of the temperature sensor, the shape of the object to be measured, and the ambient temperature. It seems necessary.

The contact failure detection device 10 and the battery management system 1 including the contact failure detection device 10 according to the third embodiment of the present invention have been described above.
The contact failure determination unit 103 included in the contact failure detection apparatus 10 according to the embodiment of the present invention includes a voltage corresponding to a change in the state of the contact failure portion when arc discharge, which is a physical quantity indicating the characteristics of arc discharge, If the abnormality determination threshold determined based on the maximum error voltage that may be included in the voltage acquired by the voltage acquisition unit 101 and the individual voltage acquisition unit 102 is exceeded, contact failure in the connection portion of the battery cell Is determined to have occurred. Moreover, the contact failure determination part 103 performs abnormality detection by a temperature sensor in parallel.
If it does in this way, generation | occurrence | production of the low voltage arc discharge and the high voltage arc discharge can be detected in a battery cell.

  The contact failure detection device 10 according to the embodiment of the present invention and the battery management system 1 including the contact failure detection device 10 have been described above. The contact failure determination unit 103 of the contact failure detection device 10 according to the embodiment of the present invention may include, for example, a microphone, detect a sound when arc discharge occurs, and determine that arc discharge has occurred. Moreover, the contact failure determination unit 103 of the contact failure detection device 10 according to the embodiment of the present invention may include an illuminance sensor, detect light when arc discharge occurs, and determine that arc discharge has occurred.

  In the processing flow according to the embodiment of the present invention, the order of processing may be changed within a range where appropriate processing is performed.

  In addition, although embodiment of this invention was described, the above-mentioned poor contact detection apparatus 10 has a computer system inside. The process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. Various omissions, replacements, and changes can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Battery management system 10 ... Contact failure detection apparatus 20 ... Output part 30, 30a, 30b ... Battery module 40 ... Battery control circuit 50 ... High-order control apparatus 60 ... Charge Discharge device 70 ... Load 80 ... Storage unit 101 ... Overall voltage acquisition unit 102 ... Individual voltage acquisition unit 103 ... Contact failure determination unit 201 ... Display unit 202 ... Speaker 203. ..Vibration part

Claims (10)

An overall voltage acquisition unit for acquiring the entire voltage of the secondary battery module;
An individual voltage acquisition unit that acquires each voltage of a plurality of battery cells included in the secondary battery module;
The difference between the sum of the voltages acquired by the individual voltage acquisition unit and the voltage acquired by the overall voltage acquisition unit, and a threshold value determined based on a physical quantity indicating the characteristics of arc discharge inside the secondary battery module; A contact failure detection device comprising: a contact failure determination unit that determines that a contact failure has occurred in a connection portion of the battery cells based on the above. The contact failure determination unit includes, as a physical quantity indicating a characteristic of arc discharge, a voltage corresponding to a change in a state of a contact failure part when the arc discharge occurs, the overall voltage acquisition unit, and the individual voltage acquisition unit. The contact failure determination is made in the connection part of the battery cell when the abnormality determination threshold value determined based on the maximum error voltage that may be included in the acquired voltage is exceeded. Contact failure detection device. The contact failure determination unit detects, as a physical quantity indicating the characteristics of arc discharge, a current flowing in a plurality of rows of battery cells connected in parallel to a row in which a plurality of secondary battery modules are connected in series, and each detected row Currents are classified into sets for each predetermined current range, and abnormal current flows through battery cells in a set other than the set having the largest number of columns in each classified set, and the connection portion of the battery cells The contact failure detection device according to claim 1, wherein it is determined that a contact failure has occurred. The contact failure determination unit detects a voltage difference and a current of each column in which a plurality of secondary battery modules are connected in series as a physical quantity indicating a characteristic of arc discharge, and a time-series waveform of the voltage difference and the current of each column The contact failure detection device according to any one of claims 1 to 3, wherein a contact failure is determined to occur at a connection portion of the battery cells in a case where is consistent with an arc discharge pattern waveform. The contact failure determination unit detects heat at the time of occurrence of arc discharge using a temperature sensor and determines that contact failure has occurred in a connection portion of the battery cell. The contact failure detection apparatus of description. The contact failure determination unit detects light when arc discharge occurs using an illuminance sensor, and determines that contact failure has occurred in a connection portion of the battery cell. The contact failure detection apparatus of description. The contact failure determination unit detects a sound at the time of occurrence of arc discharge using a microphone, and determines that a contact failure has occurred in a connection portion of the battery cell. The contact failure detection device described.   A battery management system provided with the contact failure detection apparatus as described in any one of Claims 1-7. Get the overall voltage of the secondary battery module,
Obtaining each voltage of the plurality of battery cells provided in the secondary battery module;
The contact portion of the battery cell is contacted based on a difference between the acquired voltage sum and the acquired voltage, and a threshold value determined based on a physical quantity indicating characteristics of arc discharge inside the secondary battery module. A contact failure detection method for determining that a failure has occurred. The computer of the contact failure detection device,
An overall voltage acquisition means for acquiring the entire voltage of the secondary battery module;
Individual voltage acquisition means for acquiring the voltage of each of the plurality of battery cells provided in the secondary battery module;
A threshold value determined based on a difference between a sum of voltages acquired by the individual voltage acquisition means and a voltage acquired by the overall voltage acquisition means, and a physical quantity indicating characteristics of arc discharge inside the secondary battery module; Based on the above, a program for functioning as a contact failure determination means for determining that a contact failure has occurred in the connection portion of the battery cells.

Images