JPWO2015015549A1 - Battery system monitoring device - Google Patents

Abstract

The battery system monitoring device includes a plurality of voltage measurement lines connected to each battery cell, an integrated circuit that detects the voltage of each battery cell via the voltage measurement line, and a positive electrode side of the uppermost battery cell in the assembled battery. Connected between the main power line and the ground line to supply power from the assembled battery to the integrated circuit, the main power line to be connected, the ground line connected to the negative electrode side of the lowest battery cell in the assembled battery And a current limiting element provided on at least one of the main power line and the ground line.

Description

  The present invention relates to a battery system monitoring device.

  Conventionally, an assembled battery composed of a plurality of cell batteries connected in series and a circuit for detecting the cell voltage of each cell battery are connected via a plurality of voltage measurement lines. An apparatus provided with a current protection fuse is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-75504

  Since the apparatus described in Patent Document 1 is provided with a fuse in each voltage measurement line, the number of necessary fuses increases as the number of cell batteries constituting the assembled battery increases. Therefore, in the case of an assembled battery that generates a high voltage using a large number of battery cells, such as a vehicle driving battery mounted on an electric vehicle, a large number of fuses are required, which increases the size and cost of the device. There is a problem of inviting.

  A battery system monitoring apparatus according to the present invention is connected to an assembled battery in which a plurality of battery cells are connected in series to monitor the state of each battery cell, and includes a plurality of voltage measurement lines respectively connected to the battery cells, An integrated circuit that is connected to the voltage measurement line and detects the voltage of each battery cell via the voltage measurement line, a main power supply line that is connected to the positive electrode side of the uppermost battery cell in the assembled battery, and the highest in the assembled battery. A ground line connected to the negative side of the lower battery cell, a power supply connected between the main power line and the ground line to supply power from the assembled battery to the integrated circuit, and a main power line and a ground line. A current limiting element provided on at least one of them.

  According to the present invention, it is possible to prevent an overcurrent from flowing between the assembled battery and a circuit that performs voltage detection without providing a large number of fuses.

It is a figure which shows the structure of the battery system monitoring apparatus by a comparative example. It is a figure which shows the structure of the battery system monitoring apparatus by the 1st Embodiment of this invention. It is a figure which shows the structure of the battery system monitoring apparatus by the 2nd Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, an example in which the present invention is applied to a battery system monitoring device that monitors a battery system used in a hybrid vehicle (HEV) or the like will be described. The application range of the battery system monitoring device according to the present invention is not limited to monitoring the battery system mounted on the HEV. For example, the present invention can be widely applied to devices that monitor battery systems mounted on plug-in hybrid vehicles (PHEV), electric vehicles (EV), railway vehicles, and the like.

  In the following embodiments, a predetermined output voltage range, for example, 3.0 to 4.2 V is used as a minimum unit of a battery system (assembled battery) to be controlled and monitored by being connected to the battery system monitoring apparatus according to the present invention. A lithium ion battery having an output voltage range of (average output voltage: 3.6 V) is assumed. However, the battery system monitoring apparatus according to the present invention may control and monitor a battery system configured using a power storage / discharge device other than a lithium ion battery. In other words, if the SOC (State Of Charge) is too high (overcharge) or too low (overdischarge), it is necessary to limit its use, and any battery storage / discharge device is used to configure the battery system. May be. In the following description, the power storage / discharge device as a component of such a battery system is generically referred to as a battery cell.

  In the following description, an example of a conventional battery system monitoring device will be described first as a comparative example with the present invention. FIG. 1 is a diagram illustrating a configuration of a battery system monitoring apparatus according to a comparative example. The battery system monitoring apparatus shown in FIG. 1 is connected to a battery unit 1 that is an assembled battery, and includes an integrated circuit 2, a power supply unit 3, an RC filter 4, a discharge resistor 5, a noise countermeasure capacitor 6, and a fuse 7. Yes.

  The battery unit 1 is an assembled battery in which n−1 battery cells are connected in series, and functions as a battery system that is controlled and monitored by the battery monitoring system monitoring device in FIG. 1. Each battery cell of the battery unit 1 is connected to n voltage measurement lines SL1 to SLn and n balancing lines BL1 to BLn that are branched from the voltage measurement lines SL1 to SLn, respectively. Further, the main power line MB is connected via a resistor to the positive electrode side of the battery cell arranged at the highest level, that is, the highest potential side in the battery unit 1, and the lowest level, that is, the highest level in the battery unit 1. A ground line GND is connected to the negative electrode side of the battery cell arranged on the low potential side. 1 shows an example in which n-1 battery cells are connected in series in the battery unit 1, but the number of battery cells constituting the battery unit 1 is not limited to this.

  The integrated circuit 2 is connected to the voltage measurement lines SL1 to SLn, the balancing lines BL1 to BLn, the main power supply line MB, and the ground line GND, and the voltage of each battery cell of the battery unit 1 via the voltage measurement lines SL1 to SLn. Is detected. Based on the voltage detection result of each battery cell by the integrated circuit 2, the battery monitoring system monitoring device in FIG. 1 executes a predetermined operation for controlling and monitoring the battery unit 1. For example, when the state of charge (SOC) of each battery cell is estimated and the state of charge varies between the battery cells, the balancing line BL1 to BLn is routed through the balancing line corresponding to the battery cell to be discharged. By balancing the discharge current, balancing for equalizing the state of charge of each battery cell is performed. In addition to this, based on the voltage of each battery cell detected by the integrated circuit 2, the battery monitoring system monitoring device can perform various processes and controls.

  A capacitor for stabilizing the discharge current is connected between the balancing lines BL1 to BLn adjacent to each other. In the integrated circuit 2, the voltage measurement lines SL1 to SLn and the balancing lines BL1 to BLn are connected to the main power supply line MB and the ground line GND through ESD protection diodes, respectively.

  The power supply unit 3 is for supplying power from the battery unit 1 to the integrated circuit 2 and is connected between the main power supply line MB and the ground line GND. The power supply unit 3 includes a Zener diode and a capacitor, and uses them to protect the power input terminal of the integrated circuit 2 connected to the main power supply line MB from overvoltage and overcurrent.

  The RC filter 4 is a filter circuit for removing high-frequency noise superimposed on the voltage signal of each battery cell input to the integrated circuit 2 from the voltage measurement lines SL1 to SLn, and is applied to each of the voltage measurement lines SL1 to SLn. It consists of a resistor and a capacitor provided. The RC filter 4 is provided between the branch points to the balancing lines BL1 to BLn and the integrated circuit 2 in the voltage measurement lines SL1 to SLn.

  The discharge resistor 5 is a resistance element for adjusting the discharge current flowing through the balancing lines BL1 to BLn during balancing, and is provided in each of the balancing lines BL1 to BLn.

  The noise countermeasure capacitor 6 is for reducing noise generated between the voltage measurement lines adjacent to each other among the voltage measurement lines SL1 to SLn. The noise countermeasure capacitor 6 is provided between the branch points to the balancing lines BL1 to BLn and the battery cells of the battery unit 1 in the voltage measurement lines SL1 to SLn. In the example of FIG. 1, by providing two noise suppression capacitors 6 in series between the voltage measurement lines SL1 to SLn, even if one of them is short-circuited, a large current is generated between adjacent voltage measurement lines. However, the number of noise countermeasure capacitors 6 is not limited to this.

  The fuse 7 is a current limiting element for preventing an overcurrent from flowing through the voltage measurement lines SL1 to SLn, and is provided between each of the voltage measurement lines SL1 to SLn and each battery cell of the battery unit 1. .

  In the battery system monitoring apparatus according to the comparative example described above, the fuse 7 is provided for each of the voltage measurement lines SL1 to SLn. For this reason, when the battery unit 1 is composed of a large number of battery cells, the number of voltage measurement lines increases accordingly, and thus a large number of fuses 7 are necessary, leading to an increase in the size and cost of the device. End up.

  Therefore, in the present invention, the above-described problems are solved by adopting a configuration as described in the following first and second embodiments.

(First embodiment)
FIG. 2 is a diagram showing a configuration of the battery system monitoring apparatus according to the first embodiment of the present invention. The battery system monitoring device shown in FIG. 2 differs from the comparative example shown in FIG. 1 in that the noise countermeasure capacitor 6 is not provided and that the fuse 7 is replaced with fuses 7A and 7B. is there.

  The fuses 7A and 7B are current limiting elements for preventing overcurrent similar to the fuse 7 of FIG. 1, and are provided on the main power supply line MB and the ground line GND, respectively.

  As described above, in the battery system monitoring apparatus of FIG. 2, the fuses 7A and 7B are provided only for the main power supply line MB and the ground line GND without providing a fuse for each of the voltage measurement lines SL1 to SLn. ing. Therefore, the space for mounting the fuses 7A and 7B is constant regardless of the number of battery cells constituting the battery unit 1, and thus the size of the apparatus is not increased as in the comparative example. Further, since the number of fuses 7A and 7B is constant, the cost does not increase as in the comparative example.

  In addition, since the noise countermeasure capacitor 6 as shown in FIG. 1 is not provided in the battery system monitoring device of FIG. 2, the cost can be further reduced as compared with the comparative example. In the present embodiment, the noise countermeasure capacitor 6 is not provided because the RC filter 4 can sufficiently remove noise. However, when the RC filter 4 alone is not sufficient for noise removal, a noise countermeasure capacitor 6 may be provided as shown in FIG.

  Here, consider a case where a short-circuit failure occurs in the battery system monitoring apparatus of FIG. The most dangerous short-circuit failure that can occur in the battery system monitoring device of FIG. 2 is that the power supply unit 3 is short-circuited, so that the total voltage of all battery cells of the battery unit 1 is applied between the main power supply line MB and the ground line GND. Therefore, it is a fault that a large current flows through these. However, when such a short-circuit failure occurs, at least one of the fuses 7A and 7B is melted, so that it is possible to prevent a large current from continuing to flow and generate heat and fire.

  Further, when one of the ESD protection diodes provided in the integrated circuit 2 is short-circuited, the voltage measurement line or balancing line corresponding to the ESD protection diode and the main power supply line MB or the ground line GND are passed. As a result, a large current may flow. However, even when such a short-circuit failure occurs, since either one of the fuses 7A or 7B is melted, it is possible to prevent a large current from continuing to flow and generate heat or fire.

  In addition, when the capacitor provided between the balancing lines adjacent to each other among the balancing lines BL1 to BLn fails, a current flows through the balancing line. However, since this current is the same as the discharge current flowing during the above-described balancing, no heat generation or ignition occurs.

  As described above, according to the battery system monitoring apparatus of the first embodiment of the present invention, it is possible to effectively prevent heat generation and ignition due to a short circuit failure while solving the problems as in the comparative example. .

  In the first embodiment described above, the fuses 7A and 7B are provided on the main power supply line MB and the ground line GND, respectively, but only one of them may be provided. In such a case, a large current due to a short circuit failure of the power supply unit 3 as described above can be reliably prevented, but a large current due to a short circuit failure of the ESD protection diode may not be prevented. However, even if it does in this way, generation | occurrence | production of the heat_generation | fever and ignition by a short circuit failure can be prevented to some extent, eliminating the problem like a comparative example. That is, in the battery system monitoring apparatus according to the present invention, fuses 7A and 7B as current limiting elements can be provided in at least one of main power supply line MB and ground line GND.

  According to the 1st Embodiment of this invention demonstrated above, there exist the following effects.

(1) The battery system monitoring device is connected to the battery unit 1 which is an assembled battery in which a plurality of battery cells are connected in series, and monitors the state of each battery cell. This battery system monitoring apparatus is integrated with voltage measurement lines SL1 to SLn connected to battery cells and voltage measurement lines SL1 to SLn, respectively, and detects the voltage of each battery cell via the voltage measurement lines SL1 to SLn. The circuit 2, the main power supply line MB connected to the positive electrode side of the uppermost battery cell in the battery unit 1, the ground line GND connected to the negative electrode side of the lowermost battery cell in the battery unit 1, and the battery unit 1 A power supply unit 3 connected between the main power supply line MB and the ground line GND for supplying power to the integrated circuit 2, and a current limiting element provided on at least one of the main power supply line MB and the ground line GND Fuses 7A and 7B. Since it did in this way, it can prevent that an overcurrent flows between the battery part 1 and the integrated circuit 2 which performs voltage detection, without providing many fuses.

(2) In the battery system monitoring apparatus, fuses 7A and 7B can be provided in both the main power supply line MB and the ground line GND. In this way, it is possible to effectively prevent the generation of heat and fire due to a large current flowing due to a short circuit failure in the power supply unit 3 or a short circuit failure in the ESD protection diode provided in the integrated circuit 2. it can.

(3) The battery system monitoring device includes balancing lines BL1 to BLn that are branched from the voltage measurement lines SL1 to SLn, resistors, and capacitors, and to the balancing lines BL1 to BLn in the voltage measurement lines SL1 to SLn. RC filter 4 provided between each branch point and integrated circuit 2 and discharge resistor 5 provided on each of balancing lines BL1 to BLn. This battery system monitoring device includes a noise countermeasure capacitor 6 for reducing noise generated between the voltage measurement lines SL1 to SLn adjacent to each other between the branch points of the voltage measurement lines SL1 to SLn and the battery cells. Not provided. Therefore, further cost reduction can be realized.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 3 is a diagram showing a configuration of a battery system monitoring apparatus according to the second embodiment of the present invention. In the battery system monitoring apparatus shown in FIG. 3, the difference from the first embodiment shown in FIG. 2 is that a fuse 7A is not provided, and a fusing detection circuit 8 for detecting fusing of the fuse 7B is provided. This is the point.

  The fusing detection circuit 8 has a pull-up resistor having one end connected to a voltage source that outputs a predetermined reference voltage and an intermediate point connected to the fuse 7 </ b> B and the power supply unit 3. The other end of this pull-up resistor is connected to the input terminal of the integrated circuit 2 for measuring the voltage value of the pull-up resistor. That is, the fusing detection circuit 8 includes a pull-up resistor and the integrated circuit 2.

  When the fuse 7B is not blown, the integrated circuit 2 receives the ground potential connected via the fuse 7B. On the other hand, when the fuse 7B is blown, a voltage different from the ground potential is input to the integrated circuit 2. This voltage changes as follows depending on whether the power supply unit 3 is short-circuited or not.

  When the fuse 7B is blown without the power supply unit 3 being short-circuited, the intermediate point of the pull-up resistor is disconnected from any potential, so that the reference voltage from the voltage source is passed through the pull-up resistor. Input to the integrated circuit 2. Therefore, by detecting the reference voltage from the voltage source by the integrated circuit 2, the fusing detection circuit 8 can detect the fusing of the fuse 7B.

  When the power supply unit 3 is short-circuited and the fuse 7B is blown, the voltage from the uppermost battery cell of the battery unit 1 is connected to the middle point of the pull-up resistor via the power supply unit 3 and the main power supply line MB. Applied. When the applied voltage to the intermediate point exceeds the reference voltage divided by the pull-up resistor, the applied voltage is input to the integrated circuit 2 via the pull-up resistor. Therefore, by detecting the voltage applied to the intermediate point by the integrated circuit 2, the fusing detection circuit 8 can detect the fusing of the fuse 7B.

  According to the second embodiment of the present invention described above, the battery system monitoring apparatus further includes the blow detection circuit 8 that detects the blow of the fuse 7B that is a current limiting element. Therefore, when an overcurrent flows and the fuse 7B is blown, this can be reliably detected.

  The fusing detection circuit 8 is connected to a voltage source that outputs a predetermined reference voltage, and has a pull-up resistor connected to the fuse 7 </ b> B and the power supply unit 3. When the power supply unit 3 is not short-circuited, the fusing detection circuit 8 detects the fusing of the fuse 7B by detecting a reference voltage via a pull-up resistor. Further, when the power supply unit 3 is short-circuited, the fuse 7B is detected by detecting the voltage of the uppermost battery cell via the power supply unit 3 and the pull-up resistor. Since it did in this way, fusing of the fuse 7B can be reliably detected by the case where the power supply part 3 is not short-circuited and the case where it is short-circuited, respectively.

  In the second embodiment described above, the fuse 7B is provided only on the ground line GND, and the fusing detection circuit 8 detects the fusing of the fuse 7B. However, as in the first embodiment, a fuse 7A may be provided in the main power supply line MB, and a blow detection circuit for detecting blow of the fuse 7B may be further provided. In that case, the fusing detection circuit can be configured using a pull-up resistor and the integrated circuit 2, similarly to the fusing detection circuit 8 of FIG. Specifically, when the fuse 7A is blown without a short circuit failure in the power supply unit 3, the fuse 7A is blown by detecting the reference voltage from the voltage source via the pull-up resistor by the integrated circuit 2. To detect. On the other hand, when the power supply unit 3 is short-circuited and the fuse 7A is blown, the voltage applied to the middle point of the pull-up resistor from the lowest battery cell of the battery unit 1 via the power supply unit 3 and the ground line GND Is detected by the integrated circuit 2 via a pull-up resistor, thereby detecting the blow of the fuse 7A. In this way, even when the fuses 7A and 7B are provided in both the main power supply line MB and the ground line GND, it is possible to reliably detect each fusing.

  Each embodiment and modification described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

DESCRIPTION OF SYMBOLS 1 ... Battery part, 2 ... Integrated circuit, 3 ... Power supply part, 4 ... RC filter, 5 ... Discharge resistance,
6 ... Noise suppression capacitor, 7, 7A, 7B ... Fuse, 8 ... Fusing detection circuit,
SL1-SLn ... voltage measurement line, BL1-BLn ... balancing line,
MB ... Main power line, GND ... Ground line

Claims (5)

A battery system monitoring device connected to an assembled battery in which a plurality of battery cells are connected in series to monitor the state of each battery cell,
A plurality of voltage measurement lines respectively connected to the battery cells;
An integrated circuit connected to the voltage measurement line and detecting the voltage of each battery cell via the voltage measurement line;
A main power line connected to the positive electrode side of the uppermost battery cell in the assembled battery;
A ground line connected to the negative electrode side of the lowest battery cell in the assembled battery;
A power source connected between the main power line and the ground line for supplying power from the assembled battery to the integrated circuit;
A battery system monitoring device comprising: a current limiting element provided on at least one of the main power supply line and the ground line. The battery system monitoring device according to claim 1,
A battery system monitoring device in which the current limiting element is provided in both the main power supply line and the ground line. The battery system monitoring device according to claim 1 or 2,
A plurality of balancing lines each branched from the voltage measurement line;
RC filters each comprising a resistor and a capacitor, and provided between the branch point to the balancing line and the integrated circuit in the voltage measurement line,
A discharge resistor provided in each of the balancing lines;
A battery system monitoring apparatus in which a capacitor for reducing noise generated between adjacent voltage measurement lines is not provided between the branch point of the voltage measurement line and the battery cell. The battery system monitoring device according to claim 1 or 2,
The current limiting element is a fuse;
A battery system monitoring device further comprising a fusing detection circuit for detecting fusing of the fuse. The battery system monitoring device according to claim 4,
The fusing detection circuit is connected to a voltage source that outputs a predetermined reference voltage, and has a pull-up resistor connected to the fuse and the power supply unit,
If the power supply is not short-circuited, by detecting the reference voltage via the pull-up resistor, to detect the blow of the fuse,
A battery system monitoring device that detects the blow of the fuse by detecting the voltage of the uppermost or lowermost battery cell via the power supply unit and the pull-up resistor when the power supply unit is short-circuited. .

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