JP2001174531A - Battery battery abnormality detection device - Google Patents

Abstract

(57) [Problem] To provide a lower-cost apparatus for determining an abnormality occurring in a battery pack when performing charge / discharge control of the battery pack. SOLUTION: Each cell group 1 constituting the assembled battery 19
2, a series circuit 22 and a transistor 24 are arranged for each unit cell 11 constituting each cell group 12, and when a terminal voltage of any one of the unit cells 11 exceeds an upper limit voltage, an ON voltage is supplied to the transistor 24. Then, when the gate voltage of the FET 34 becomes high level via the detection voltage changing means 29, the voltage output of the cell group 12 is cut off. Then, the supply of power to the voltage detector 14 of the ECU 18 is cut off, and the CPU 17
It is determined that an abnormality has occurred in the cell group 12 by referring to the output voltage level of the voltage detector 14 via the.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack comprising a plurality of unit cells connected in series to form a cell group. The present invention relates to an abnormality determination device that determines the occurrence of an abnormality in the apparatus.

[0002]

2. Description of the Related Art In recent years, a hybrid electric vehicle (hereinafter, referred to as a hybrid vehicle) combining a mechanism of an electric vehicle and a gasoline engine has been developed in order to achieve both low pollution and high running performance.
HEV) has been developed. In HEV,
Since the electric power supplied from the battery is used at the time of starting or full acceleration, a high output is required for the battery. In addition, the HEV has to mount many components such as an engine, a motor / generator, and a battery, and the weight of the entire vehicle increases. Is required.

[0003] Under such circumstances, attention has been paid to lithium batteries as an alternative to lead, nickel cadmium, nickel hydride batteries and the like. Lithium batteries have a weight energy density that is about three to four times higher than lead or nickel cadmium batteries of the same capacity, and are expected to be applied as suitable for HEVs that require small size and light weight. I have.

However, lithium batteries are susceptible to overcharging and overdischarging, and if not used within a specified voltage range, materials may be decomposed and markedly reduced in capacity, or may become unusable due to abnormal heat generation. There is. Therefore, when using a lithium battery, the upper limit voltage and the lower limit voltage are clearly specified, and charge / discharge control is performed so that the terminal voltage is within the range, or a protection circuit that limits the voltage range is used as a set. It is common to use.

[0005] A battery used in an electric vehicle or an HEV requires a high voltage to drive a motor. Therefore, a battery is usually constituted by connecting a plurality of unit cells in series. For example, to obtain a battery voltage of 300 V, about 150 cells are connected in series for a 2 V lead battery per unit cell, and about 80 cells are connected in series for a 3.6 V lithium battery per unit cell. Become.

In the case of charging and discharging a battery pack formed by connecting a large number of unit cells in series as described above, conventionally, charging / discharging is controlled by monitoring the voltage between the positive and negative terminals of the battery pack. For example, the voltage range per unit cell is 1.8 to
In the case of a series of lead batteries of 2.4 V at 150 batteries, the charge / discharge control is performed so that the voltage range of the assembled battery is in the range of 270 to 360 V.

However, since the remaining capacity of each unit cell has a variation mainly caused by a difference in self-discharge and charge / discharge efficiency of each cell, a variation also occurs in a terminal voltage between each unit cell. Is inevitable.
Since the variation in the remaining capacity is accumulated and expanded with time, even if the total terminal voltage of the assembled battery is monitored and charging is controlled, the terminal voltage of each unit cell is ( Some are higher or lower than the average voltage obtained by (terminal voltage of battery) / (number of unit cells). Therefore, there is a unit cell that is overcharged when charged to the upper limit voltage and overdischarged when discharged to the lower limit voltage.

In the case of NiCd or NiMH batteries, even if overdischarge or overcharge occurs, there is little deterioration in performance.
In addition, even if the performance of the lead battery is deteriorated, there is no particular problem in the safety, and neither of them is in an unusable state. Therefore, it is sufficient to control the lead battery with reference to only the voltage across the assembled battery.
However, when using a lithium battery as a multi-series battery pack, it is necessary to take measures to prevent each unit cell from being overcharged or overdischarged, that is, to prevent occurrence of abnormalities such as overcharge and overdischarge. It is essential to detect and judge.

[0009]

As a countermeasure for such a countermeasure, there is, for example, one disclosed in Japanese Utility Model Laid-Open No. 2-136445. In this prior art, as shown in FIG. 11, a voltage detector 3 for individually detecting each terminal voltage is connected in parallel to each unit cell 2 constituting the battery pack 1. The CPU 5 constituting the abnormality determination ECU 4 obtains the detection signals of the respective voltage detectors 3 through the multiplexers 6, 7 and 8 and the A / D converter 9.

The CPU 5 detects the highest value of the terminal voltages of the unit cells 1 at the time of charging and performs control so that the highest voltage does not exceed the upper limit voltage, and detects the lowest value at the time of discharging. Then, when the minimum voltage reaches the lower limit voltage, control is performed so as to end the discharge.

However, in such a system, a voltage detector 3 must be provided for each unit cell 2 in order to monitor the occurrence of overcharge or overdischarge. Then, in order to process a large number of detection signals output from each voltage detector 3, multiplexers 5 to 8 are required. In addition, E which is arranged at a position relatively far from the battery pack 1 from the unit cell 2
Since the number of wirings to the voltage detector 3 built in the CU 4 also increases, there is a problem that the cost is generally increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a device for judging an abnormality occurring in a battery pack when performing charge / discharge control of the battery pack, at a lower cost. Consists in configuring.

[0013]

According to the battery pack abnormality detecting device of the present invention, in each cell group constituting the battery pack, the on-voltage supply means is a unit constituting each cell group. When the terminal voltage of the cell exceeds the upper limit voltage, a predetermined ON voltage is supplied to the detection switching element,
The detection voltage changing means changes the detection voltage when the detection switching element is turned on. Then, the voltage detecting means detects a change in voltage caused by a change in the on / off state of the detection switching element, and the abnormality determining means determines that an abnormality has occurred in the cell group based on the voltage detected by the voltage detecting means. Is determined.

In other words, when the terminal voltage of the unit cell exceeds the upper limit voltage and the ON voltage is supplied to the switching element for detection and the switching element is turned ON, the change in the voltage causes a change in the voltage to the cell group including the unit cell. It can be determined that an abnormality has occurred. Therefore, by setting the upper limit voltage to be equal to the threshold voltage at which the unit cell serving as the secondary battery is in the overcharged state, the abnormality determination unit determines the cell group including the unit cell in the overcharged state. Can be detected. By determining the abnormality for each cell group, the number of components and harnesses required for abnormality detection can be reduced as compared with the related art, so that the configuration can be performed at a lower cost than before.

According to the second aspect of the present invention, in each of the cell groups constituting the assembled battery, the on-voltage supply means sets the terminal voltage of the unit cell constituting each cell group to a lower limit. If the voltage is equal to or more than the voltage, a predetermined ON voltage is supplied to the detection switching element, and the detection voltage changing means changes the detection voltage when the detection switching element is turned off. Then, the voltage detecting means detects a change in voltage caused by a change in the on / off state of the detection switching element, and the abnormality determining means determines that an abnormality has occurred in the cell group based on the voltage detected by the voltage detecting means. Is determined.

Therefore, by setting the lower limit voltage to be equal to the threshold voltage at which the unit cell is in the overdischarged state, the abnormality determining means detects the cell group including the unit cell in the overdischarged state. Therefore, the same effect as the first aspect can be obtained.

According to the battery pack abnormality detecting device of the third aspect, in each cell group constituting the battery pack, the first
The on-voltage supply means supplies a predetermined on-voltage to the first detection switching element when the terminal voltage of the unit cell constituting each cell group exceeds the upper limit voltage, and the second on-voltage supply means outputs If the terminal voltage of the cell is lower limit voltage abnormal, a predetermined ON voltage is supplied to the second detection switching element. The first detection voltage changing means changes the detection voltage when the first detection switching element is turned on, and the second detection voltage changing means changes the detection voltage when the second detection switching element is turned off.

Further, the voltage detecting means includes a first or second
A voltage change associated with a change in the on / off state of the detection switching element is detected, and the abnormality determination unit determines that an abnormality has occurred in the cell group based on the voltage detected by the voltage detection unit. Therefore, it is possible to detect both the case where any of the unit cells is in the overcharged state and the case where the unit cell is in the overdischarged state.

According to the fourth aspect of the present invention, the cutoff switching element operates to cut off the voltage output of the cell group when the detected voltage changes by the detected voltage changing means. Then, the voltage detecting means detects a change in voltage caused by the interruption of the voltage output of the cell group by the interruption switching element.

Therefore, when the terminal voltage of the unit cell exceeds the upper limit voltage or falls below the lower limit voltage, the voltage output of the cell group is cut off by the cutoff switching element, and the voltage change caused by the cutoff is changed. Since the voltage is detected by the voltage detecting means, the abnormality can be easily detected.

According to the abnormality detecting device for a battery pack according to the fifth aspect, the switching element for detection and the on-voltage supply means are arranged for all of the unit cells constituting the cell group. It can be performed more reliably.

According to the present invention, the ON voltage supply means is constituted by a series circuit of a resistor connected in parallel to the unit cell and a reference voltage generation means for generating a predetermined reference voltage. Then, a predetermined ON voltage is supplied to the detection switching element by the terminal voltage of the resistor.

That is, since the terminal voltage of the resistor is a difference voltage between the terminal voltage of the unit cell and the reference voltage, the sum of the reference voltage and the ON voltage of the switching element for detection is equal to the upper limit voltage or the lower limit voltage of the unit cell. By setting so as to be equal to, the switching operation of the detection switching element can be performed as expected.

According to the abnormality detecting apparatus for a battery pack of the present invention, since the reference voltage generating means is constituted by a Zener diode, the element whose Zener voltage is set to an appropriate value is appropriately selected. It can easily correspond to the upper limit voltage or the lower limit voltage set for various unit cells.

According to the abnormality detecting device for an assembled battery of the present invention, the reference voltage generating means is constituted by a band gap reference. Similarly, it can easily correspond to the upper limit voltage or the lower limit voltage set for various unit cells. In addition, the accuracy of the reference voltage can be improved by reducing the fluctuation of the reference voltage, and the power consumption of the reference voltage generating means can be further reduced.

According to the abnormality detecting device for a battery pack according to the ninth aspect, since the switching element for detection is constituted by a bipolar transistor, the cutoff current in the off state can be extremely reduced, and the power consumption can be suppressed. It is possible to do.

According to the abnormality detecting device for a battery pack of the present invention, since the detection voltage changing means is constituted by the bipolar transistor, the on / off state of the transistor is changed in response to the change of the on / off state of the detection switching element. , The detection voltage can be easily changed.

[0028] According to the abnormality detecting device for an assembled battery according to the eleventh aspect, the switching element for cutoff is constituted by the MOSFET arranged between the positive electrode side of the cell group and the voltage detecting means. , The driving power can be reduced. In addition, since the ON resistance is small, the voltage drop is small, and the error in voltage detection by the voltage detecting means can be reduced.

According to the apparatus for detecting abnormality of a battery pack according to the twelfth aspect, the discharge means connected in parallel to each cell group via the discharge resistor so as to adjust the variation of the terminal voltage between the cell groups. By performing the discharge and maintaining the terminal voltages between the cell groups to be substantially equal at all times, it is possible to improve the use efficiency of the assembled battery.

According to the abnormality detecting device for a battery pack of the present invention, the switching element for shutting down is constituted by a MOSFET, and the discharge control means controls the voltage detection means to detect the voltage of any of the cell groups. Control is performed so as to prohibit discharge by discharge means arranged on the high potential side of the cell group.

That is, when the voltage detecting means attempts to detect a voltage for a cell group in which the switching element for shutting off is in the off state, the discharging means is used for the cell group arranged on the high potential side of the cell group. Is discharged, the discharge current becomes MOSFE
This flows into the positive electrode side of the cell group that is the target of voltage detection via the parasitic diode formed at T. Then, the voltage detection means cannot detect that the cutoff switching element is in the off state due to the change in the voltage as the on / off state of the detection switching element changes.

Accordingly, by performing the above-described control by the discharge control means, the discharge is performed in the cell group on the high potential side, and at the same time, the on / off state of the switching element for detection is detected in the cell group to be detected. Can also be detected.

According to the abnormality detecting apparatus for a battery pack, the switching element for disconnection is constituted by a MOSFET, and the discharge path forming means turns off the switching element for disconnection arranged in any one of the cell groups. In the case where the cell group is in the state, and the discharge is being performed by the discharge means in the cell group arranged on the high potential side of the cell group, the discharge current is supplied to the negative side of the former cell group. Form a discharge path to guide.

In the discharge path, there is provided a voltage dividing resistor for dividing the series terminal voltage of the former cell group and the cell group arranged on the higher potential side together with the discharging resistance of the discharging means. If the shut-off switching element of a certain cell group is turned off and the cell group on the higher potential side is discharging at the same time, the series resistor voltage of the two cell groups is used as the voltage dividing resistor. A divided potential corresponding to the resistance ratio with the divided resistor appears.

Accordingly, at this time, since the voltage detecting means detects the divided potential which is significantly lower than the terminal voltage of the normal cell group, the discharge is performed in the cell group on the higher potential side. Even in this case, it is possible to detect in parallel that an abnormality has occurred in the cell group.

According to the abnormality detecting device for a battery pack of the present invention, the shut-off switching element is constituted by two MOSFETs connected in opposite directions between the positive electrode side of the cell group and the voltage detecting means. , These two MOs
The SFETs are simultaneously turned off when the voltage converted by the voltage conversion means changes.

That is, since a parasitic diode connected in parallel in the reverse direction is formed between the source and the drain of the MOSFET, when one MOSFET cuts off between the positive electrode side of the cell group and the voltage detecting means. When a discharge occurs in the cell group located on the high potential side, the discharge current flows from the negative side of the high potential side cell group to the positive side of the cell group via the parasitic diode of the MOSFET which is in an off state. become.

Therefore, in this case, even if the MOSFET is turned off, the voltage detecting means corresponding to the cell group will detect the terminal voltage of the high-potential side cell group. Cannot be detected as being turned off.

Therefore, two MOS transistors connected in opposite directions are provided between the positive electrode side of the cell group and the voltage detecting means.
If an FET is arranged and both are turned off simultaneously with the change of the on / off state of the detection switching element, the parasitic diode is connected in series in the opposite direction to each other. It can be prevented from flowing to the positive side of the cell group via the diode, and it is possible to detect in parallel that an abnormality has occurred in the cell group even when discharging is performed on the high potential side. Become.

According to the abnormality detecting device for a battery pack of the present invention, the switching element for detection, the ON voltage supply means,
An abnormality detection unit including a detection voltage changing means and a switching element for shut-off is provided, and operation power is supplied from the corresponding cell group to the abnormality detection unit. Therefore, there is no need to prepare a separate operation power supply and the configuration is simplified. Can be

According to the battery cell abnormality detecting device of the present invention, since the unit cell is a lithium battery, the lithium battery has a high energy density, but requires more strict measures for overcharge and overdischarge. Even when is used, the charge / discharge can be controlled safely.

According to the battery pack abnormality detecting device of the present invention, since the battery pack is used as a driving battery for an electric vehicle or a hybrid electric vehicle, the battery pack having a relatively large number of unit cells connected in series can be used. Thus, the effect of reducing the number of components and the number of harnesses can be extremely effectively exerted.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing an outline of the electrical configuration, a unit group 11 composed of a lithium secondary battery forms a cell group 12 for every four (A) to (D) connected in series.
For the positive electrode of the unit cell 11, lithium nickel oxide is used as an active material.

An abnormality detection unit 13 and a voltage detector (voltage detection means) 14 are connected in parallel between the positive electrode and the negative electrode of each cell group 12. Each voltage detector 1
The detection signal of 4 is supplied to a multiplexer (voltage detection means) 15
Via an A / D converter (voltage detecting means) 16
A PU (abnormality determination means) 17 is provided.

The CPU 17 supplies a switching control signal to each multiplexer 15 so as to sequentially refer to the terminal voltages of each cell group 12 detected by the voltage detector 14. The voltage detector 14, multiplexer 15, A
The / D converter 16 and the CPU 17 provide an error detection E
A CU (Electronic Control Unit) 18 is configured.

In the cell group 12, 20 cells are connected in series to form a battery pack 19 (the high potential side is (1) and the low potential side is (20)).
As the HEV drive battery, the positive electrode 19p and the negative electrode 19n are connected to a charger, an inverter (not shown) for driving the HEV motor, and the like via the main current paths L + and L-. ing.

Hereinafter, the abnormality detection unit 13 (1) provided corresponding to the cell group 12 (1) will be described.
This will be described with reference to FIG. Each unit cell 11 has a resistor 2
A series circuit (on-voltage supply means) 22 of 0 and a Zener diode (reference voltage generation means) 21 is connected in parallel. The Zener diode 21 has a Zener voltage of 3.
7V is selected.

The base of a PNP-type transistor (detection switching element) 24 is connected to a common connection point between the resistor 20 and the Zener diode 21 via a base resistor 23, and the emitter of the transistor 24 is connected to a unit. It is connected to the positive terminal of the cell 21. The collector of the transistor 24 is connected via a diode 25 to one end of a resistor 26.

Four resistors 26 corresponding to each unit cell 11
(A) to (D) are connected in series,
The other end of (D) is connected to the cell group 12 via the resistor 27.
It is connected to the negative terminal of (1) and to the base of an NPN transistor 28.

The emitter of the transistor 28 is connected to the negative terminal of the cell group 12 (1), and the collector is connected to the positive terminal of the cell group 12 (1) via a series circuit of resistors 30 and 31. I have. The common connection point of the resistors 30 and 31 is connected to the base of a PNP transistor 32, and the emitter of the transistor 32 is connected to the positive terminal of the cell group 12 (1). The collector of the transistor 32 is connected to a resistor 33.
And connected to the negative terminal of the cell group 12 (1) and to the gate of a P-channel MOSFET (interrupting switching element, hereinafter simply referred to as FET) 34. A parasitic diode 34a is formed between the source and the drain of the FET 34 in an anti-parallel connection. The configuration from the diode 25 to the resistor 33 constitutes the detection voltage changing means 35.

The source of the FET 34 is the cell group 12
The drain is connected to the positive terminal of (1), and the drain is connected to the EC via the output terminal 13a (1), the harness 36 (1) and the input terminal 18a (1) of the abnormality detection unit 13.
It is connected to the non-inverting input terminal of the voltage detector 14 (1) inside U18. The voltage detector 14 (1) is configured as, for example, a differential amplifier, and its inverting input terminal has:
The input terminal 18a (2) and the harness 36 (2) are connected to the drain of the FET 34 (2) of the cell group 12 (2).

The power for operating the voltage detector 14 is supplied from the corresponding cell group 12 via the harness 36. The other abnormality detection units 13 (2) to 13 (20) have the same configuration. The abnormality detection unit 13 is disposed near each of the cell groups 12.
Are arranged near an inverter control ECU or the like.

Next, the operation of the present embodiment will be described.
The HEV discharges the assembled battery 19 because the HEV runs by driving the motor by the inverter at the time of start or low-speed operation. In addition, during high-speed operation, the vehicle is driven by driving a gasoline engine, and the assembled battery 19 is charged by rotating the motor as a generator.

Unit cell 1 composed of a lithium secondary battery
The upper limit voltage at which 1 becomes overcharged is about 4.3 V, the base-emitter voltage of the transistor 24 is 0.6 V, and the Zener voltage of the Zener diode 21 is 3.7 V. .3V is set equal to the upper limit voltage. The terminal voltage of the unit cell 11 is 4.
If the voltage is 3 V or less, the terminal voltage of the resistor 20, that is, the voltage between the base and the emitter of the transistor 24 does not reach 0.6 V, and the transistor 24 is off.

Therefore, for example, if the terminal voltages of all the unit cells 11 constituting the cell group 12 (1) are 4.3 V or less, all the transistors 24 are off, and the base potential of the transistor 28 is substantially At 0 V, the transistor 28 is also off and the transistor 32 is off. Then, since the collector potential of the transistor 32 is also approximately 0 V, the gate potential of the P-channel FET 34 becomes negative with respect to the source potential, and the FET 34 is turned on.

That is, in this case, since the power is supplied to the voltage detector 14 (1) of the ECU 18 from the cell group 12 (1) via the harness 36 (1), the voltage detector 14 (1) Outputs a signal corresponding to the difference voltage substantially corresponding to the terminal voltage of the corresponding cell group 12 (1) to the A / D converter 16 via the multiplexer 15. Therefore, if the voltage level read via the A / D converter 16 substantially corresponds to the terminal voltage of the cell group 12, the CPU 17
(1) can be determined to be normal.

On the other hand, when one of the unit cells 11 constituting the cell group 12 (1), for example, the unit cell 11 (A) is overcharged and its terminal voltage exceeds 4.3V, the corresponding transistor 24 (A) is turned on. Then, a current flows through the corresponding resistor 26 (A) in the detection voltage changing means 35 and the base potential of the transistor 28 rises, so that the base current of the transistor 28 flows and the transistor 28 is turned on. When the transistor 28 is turned on, the transistor 32 is also turned on, so that the collector potential of the transistor 32 rises, and the gate potential of the FET 34 becomes substantially equal to the terminal voltage of the cell group 12, so that the FET 34 is turned off.

Then, the supply of the operating power to the voltage detector 14 (1) is cut off, and the level of the output signal is reduced to approximately 0V. Accordingly, the CPU 17 reads the voltage detector 14 (1) read via the A / D converter 16
When the output signal level becomes approximately 0 V, it can be determined that an abnormality (overcharged state) has occurred in any of the unit cells 11 of the cell group 12 (1). Then, the CPU 17 performs a predetermined process such as outputting a signal to the control device of the inverter so as to control the power for charging the battery pack 19.

As described above, according to the present embodiment, the battery pack 1
9, a series circuit 22 and a transistor 24 are arranged for each unit cell 11 constituting each cell group 12, and when the terminal voltage of any one of the unit cells 11 exceeds the upper limit voltage. Transistor 24
When the gate voltage of the FET 34 becomes high level via the detection voltage changing means 35, the voltage output of the cell group 12 is cut off. Then, the power supply to the voltage detector 14 of the ECU 18 is cut off, and the CPU 1
7 refers to the output voltage level of the voltage detector 14 via the A / D converter 16 and determines that an abnormality has occurred in the cell group 12.

Therefore, the CPU 17 can detect the cell group 12 including the unit cell 11 which has been overcharged and has exceeded the upper limit voltage. And cell group 1
By determining the abnormality every two, it is possible to reduce the number of components and harnesses required for abnormality detection and reduce the cost as compared with the related art.
Is a HEV having a relatively large number of unit cells 11 connected in series.
, The reduction effect can be extremely effectively exerted. Further, unit cell 1
First, even when a lithium battery having a high energy density but requiring more strict overcharge measures is used, the charge and discharge of the lithium battery can be safely controlled.

Further, according to the present embodiment, the on-voltage is supplied to the transistor 24 by the series circuit 22 of the resistor 20 and the zener diode 21, so that the zener voltage of the zener diode 21 is appropriately selected so that the upper limit is obtained. The voltage can be set to various values. Since the configuration is made using the transistors 24, 28, and 32, the configuration is simplified compared to, for example, a case where a comparator composed of an operational amplifier is used to compare the terminal voltage of the unit cell 11 with the upper limit voltage. be able to. Further, since the cutoff current flowing when the transistors 24, 28, and 32 are off is extremely smaller than the dark current of the operational amplifier, power consumption can be reduced.

In addition, since the voltage output of the cell group 12 is cut off by using the MOSFET 34, the driving power can be reduced by controlling the switching by the voltage. In addition, since the on-resistance is small, the voltage drop is small, and when the output voltage of the cell group 12 is directly detected, the detection error can be reduced. Furthermore, since the power supply for operating the abnormality detection unit 13 is supplied from the corresponding cell group 12, it is not necessary to separately prepare a power supply, and the configuration is simplified.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. I will explain only. In the second embodiment, the same configuration as that of the first embodiment is applied to detection of an overdischarge state of the unit cell 11, and
FIG. 3 shows only the abnormality detection unit 13A (1) corresponding to the cell group 12 (1). That is, the Zener diode 21 of the first embodiment has a Zener voltage of 1.9V.
Is replaced by a zener diode (reference voltage generating means) 37 which is
8.

The detection voltage changing means 35 is replaced by a detection voltage changing means 39. That is, unit cell 1
The collector of the transistor 24 (A) corresponding to 1 (A) is connected to the base of the NPN transistor 40 (A). The collector of the transistor 40 (A) is connected to the positive terminal of the cell group 12 via the resistor 41 (A), and the emitter is connected to the unit cell 11 (B).
Is connected to the resistor 41 (B) corresponding to A similar configuration is provided for the other unit cells 11 (B) to 11 (D), and the emitter of the transistor 40 (D) is connected to the resistor 4
1 (E) is connected to the negative terminal of the cell group 12. Further, the collector of the transistor 40 (A) is connected to the gate of the FET 34. The above constitutes the detection voltage changing means 39.

Next, the operation of the second embodiment will be described. The lower limit voltage at which the unit cell 11 composed of a lithium secondary battery is in an overdischarge state is about 2.5 V, the base-emitter voltage of the transistor 24 is 0.6 V, and the Zener voltage of the Zener diode 37 is 1.9 V. Therefore, the sum of the two voltages is set equal to the lower limit voltage of 2.5V. If the terminal voltage of the unit cell 11 is 2.5 V or more, the terminal voltage of the resistor 20, that is, the transistor 2
4 has a voltage between the base and the emitter of 0.6 V or more, and the transistor 24 is on.

Therefore, for example, if the terminal voltage of all the unit cells 11 constituting the cell group 12 (1) is 2.5 V or more, all the transistors 24 are in the ON state, and the base current flows through the respective transistors 40. The transistor 40 is supplied and the transistor 40 is also on. Then, the gate potential of the P-channel FET 34 becomes negative with respect to the source potential, so that the FET 34 is turned on.

On the other hand, when one of the unit cells 11 constituting the cell group 12 (1), for example, the unit cell 11 (A) is in an overdischarged state and its terminal voltage falls below 2.5V, the corresponding transistor 24 (A) is turned off. Then, the supply of the base current to the transistor 40 is cut off and the transistor 40 is turned off.
Since supply of the collector current to the other transistors 40 (B) to 40 (D) in 9 is cut off, all of them are also turned off. As a result, the gate potential of the FET 34 becomes substantially equal to the terminal voltage of the cell group 12 and the FE
T34 is turned off.

Then, as in the first embodiment, the level of the output signal of the voltage detector 14 (1) drops to approximately 0 V, so that the CPU 17 reads out the voltage detector 14 via the A / D converter 16. The output signal level of (1) is approximately 0V
In this case, it can be determined that an abnormality (over-discharge state) has occurred in any of the unit cells 11 of the cell group 12 (1).

As described above, according to the second embodiment, when the terminal voltage of any one of the unit cells 11 constituting the cell group 12 falls below the lower limit voltage, the supply of the ON voltage to the transistor 24 is stopped, and 24 and all the transistors 40 of the detection voltage changing means 39 are turned off, and the FET 34 is turned off, so that the voltage output of the cell group 12 is cut off. Therefore, CPU
17 is capable of detecting the cell group 12 including the unit cell 11 which is in the overdischarged state and has fallen below the lower limit voltage,
The same effects as in the first embodiment can be obtained.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. I will explain only. In the third embodiment, the drain of the FET 34
Between the output terminal 13Ba of the abnormality detection unit 13B,
Another P-channel MOSFET (interrupting switching element) 42 is connected in the opposite direction to the FET 34,
The gate of the FET 42 is commonly connected to the gate of the FET 34.

On the other hand, inside the ECU 18A, a discharge circuit (discharge means) 45 composed of a series circuit of a normally open switch 43 and a discharge resistor 44 is connected between the input terminals of the voltage detector 14. . The CPU (abnormality detection means, discharge control means) 17A supplies a control signal to each switch 43 via the decoder 46 to control the opening and closing thereof.

Next, the operation of the third embodiment will be described. In the battery pack 19, when the terminal voltage between the cell groups 12 varies, the use efficiency is reduced. Therefore, the CPU 17A monitors the terminal voltage of each cell group 12 via the voltage detector 14, the multiplexer 15, and the A / D converter 16 in order to minimize the variation in the terminal voltage. If it is determined that the terminal voltage of any of the cell groups 12 is higher than the average, the switch 43 of the discharge circuit 45 provided corresponding to the cell group 12 is closed via the decoder 46, and the cell group 12 is closed. The terminal 12 is connected to the discharge resistor 44 to cause a discharge to be performed to lower the terminal voltage, and to equalize the terminal voltage between the respective cell groups 12.

For example, if it is determined that the terminal voltage is higher than the average in the cell group 12 (1), the CPU 17
A closes the switch 43 (1) of the discharge circuit 45 (1) and discharges the cell group 12 (1). The discharge current flows from the positive terminal of the cell group 12 (1) to the FET 34 (1). ) And 42 (1) → discharge circuit 45
(1) → FET FETs 42 (2) and 34 (2) → negative terminal of cell group 12 (1).

Next, the operation of the third embodiment will be described. Here, when the cell group 12 (1) is discharged as described above, one of the unit cells 11 constituting the cell group 12 (2) located on the negative electrode side (low potential side) is It is assumed that the battery is overcharged.

In this case, as in the first embodiment, if there is only one switching element for interrupting, the FET 34 (2) of the cell group 12 (2) is turned off to interrupt the voltage output. Also, by the parasitic diode 34a (2) formed in the FET 34 (2), the positive terminal of the cell group 12 (1) → the FET 34 (1) → the discharge circuit 45 (1) → the parasitic diode 34a (2) → the cell group 12 (1) negative electrode terminal (= cell group 12 (2)
(A positive terminal).

Then, the potential of the output terminal 13a (2) of the abnormality detection unit 13 (2) does not decrease, and the voltage detector 14 (2)
In (2), the power supply for operation is continuously supplied.
7A cannot detect the abnormality that has occurred in the cell group 12 (2).

Therefore, in the third embodiment, the two switching elements, ie, the FET 34 and the FET 42, are turned off at the same time to discharge in the cell group 12 (1) on the high potential side. In this case, the discharge path can be blocked by the parasitic diode 42a of the FET 42.
The abnormality occurring in (2) can be detected.

As described above, according to the third embodiment, the two switching elements, ie, the FET 34 and the FET 42, are used, and when an abnormality occurs in any one of the unit cells 11, both of them are simultaneously turned off. , A cell group 1
The CPU 17A can determine and detect the occurrence of the abnormality even when an abnormality occurs in the cell group 12 and the discharge by the discharge circuit 45 is performed in the cell group 12 on the high potential side, so that the abnormality can be more reliably determined. Can be done.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. I will explain only. Abnormality detection unit 13C in the fourth embodiment
Here, a relay switch 47 is used instead of the FET 34 as the switching element for shutting off.

That is, from the configuration of the first embodiment, the resistance 31
33 and the transistor 32 are also removed to form the detection voltage changing means 35 ', and the exciting coil 47a of the normally closed relay switch 47 is connected between the positive terminal of the cell group 12 and the resistor 30. . The positive contact of the cell group 12 is connected to the movable contact 47b of the relay switch 47, and the output contact 13Ca of the abnormality detection unit 13C is connected to the fixed contact 47c on the closed side. The movable contact 47b of the relay switch 47
Is normally connected to the fixed contact 47c, and when the excitation coil 47a is energized, the connection is switched to the open-side fixed contact 47d.

Next, the operation of the fourth embodiment will be described. As in the first embodiment, when the terminal voltage of any of the unit cells 11 exceeds the upper limit voltage, the corresponding transistor 24
Is turned on, a current flows through the resistor 26, and the transistor 28 is turned on. Then, a current flows through the exciting coil 47a of the relay switch 47, so that the connection of the movable contact 47b is switched from the fixed contact 47c to the fixed contact 47d,
The voltage output of the cell group 12 is cut off. According to the fourth embodiment configured as described above, the same effect as that of the first embodiment can be obtained.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention. The same parts as those of the third embodiment are denoted by the same reference numerals, and the description thereof will be omitted. I will explain only. In the abnormality detection unit 13D of the fifth embodiment, the FET 42 is omitted, and the switching element for the cutoff is only the FET 34 as in the first embodiment. The base of an NPN transistor 49 is connected to the collector of the transistor 32 via a base resistor 48. The collector of the transistor 49 is connected to the positive terminal of the cell group 12 via the resistor 50, and the emitter is connected to the negative terminal of the cell group 12.

The resistance ratio between the resistor 44 and the resistor 48 of the discharge circuit 45 is set to be, for example, about 5: 2. The resistors 48 and 50 and the transistor 4
9 constitutes a discharge path forming means 51.

Next, the operation of the fifth embodiment will be described. As in the third embodiment, when the discharge is performed by the discharge circuit 45 for the cell group 12 (1), the path of the discharge current is the positive terminal of the cell group 12 (1) → F.
ET34 (1) → discharge circuit 45 (1) → FET34
(2) → Negative electrode terminal of cell group 12 (1).

Then, it is assumed that any one of the unit cells 11 constituting the cell group 12 (2) located on the negative electrode side of the cell group 12 (1) is overcharged and the FET 34 (2) is turned off. . Then, the collector potential of the transistor 32 increases, so that a base current is supplied to the transistor 49 and the transistor 49 is turned on. In this case, the path of the discharge current is the positive terminal of the cell group 12 (1) →
FET34 (1) → discharge circuit 45 (1) → resistance 50
(2) → transistor 49 (2) → cell group 12
It becomes the negative electrode terminal of (2).

At this time, the potential difference between the output terminal 13Da of the abnormality detection unit 13D and the negative terminal of the cell group 12 (2) is determined by the series terminal voltage of the cell groups 12 (1) and 12 (2), It becomes almost equal to the potential divided by the resistor 44 and the resistor 48. For example, cell group 1
Assuming that both terminal voltages of 2 (1) and 12 (2) are 18 V, the potential difference is about (18 + 18) × 2/7.
= 10.3 (V).

If the lower limit of the normal use range of the unit cell 11 is set slightly higher than 2.5 V which leads to the overdischarge state and is set to, for example, 3.0 V, the lower limit of the use range of the cell group 12 is 3. 0V × 4 = 12.0V. Therefore, when the detected voltage obtained from the output signal of the voltage detector 14 is lower than the voltage corresponding to 12.0 V, the CPU 17A turns off the FET 34 (2) and turns on the cell group 12 (2). It can be determined that an abnormality has occurred.

As described above, according to the fifth embodiment, the discharge path forming means 51 is provided in the abnormality detection unit 13D. Even when the discharge by the discharge circuit 45 is performed in the cell group 12, the CPU 17A
Can detect abnormalities.

(Sixth Embodiment) FIGS. 7 and 8 show a sixth embodiment of the present invention. The same parts as those in the first or third embodiment are denoted by the same reference numerals and the description is omitted. Only the different parts will be described below. In the sixth embodiment, the same abnormality detection unit 13 as in the first embodiment is used. The CPU 17A is replaced with a CPU (abnormality detection means, discharge control means) 17B, and constitutes an ECU 18B.

Next, the operation of the sixth embodiment will be described with reference to FIG. FIG. 8 is a timing chart showing execution timings of (a) discharge control and (b) abnormality determination processing of the cell group 12 executed by the CPU 17B. In the seventh embodiment, the CPU 17B executes these processes in a time-sharing manner.

For example, when discharging the cell group 12 (1), as shown in FIG. 8A, the switch 43 (1) of the discharging circuit 45 (1) is connected to the switch 43 (1) via the decoder 46 from time 0 to T1. When a control signal is given to perform (ON) discharge, the output of the control signal is stopped (OFF) from time T1 to T4 to stop (prohibit) discharge. Then, at times T2 to T3 between the times T1 and T4,
The multiplexer 15 selects the voltage detector 14 (2) corresponding to the cell group 12 (2), reads its output voltage level, and performs an abnormality determination process.

During the period from time T4 to time T5, a control signal is applied to switch 43 (1) of discharge circuit 45 (1) again to discharge cell group 12 (1).
The output of the control signal is stopped from 5 to T8, and the voltage detector 14 (3) corresponding to the cell group 12 (3) is selected at the time T6 to T7 between the time T5 and T8, and the output voltage level is selected. Read. Thereafter, when the discharge of the cell group (1) is continued in the same manner, the abnormality determination processing is sequentially performed similarly for the other cell groups 12 (4) to 12 (20).

As described above, according to the sixth embodiment, the CPU
17B, while the voltage is detected for any of the cell groups 12, the discharge by the discharge circuit 45 of the cell group 12 disposed on the high potential side of the cell group 12 is prohibited.

That is, as in the first embodiment, when the abnormality detecting transistor 24 is turned on, the FET 34
When the voltage output is cut off only by the voltage detector 14, when the voltage of the cell group is detected by the voltage detector 14, if the discharge is performed in the cell group 12 on the high potential side of the cell group 12, the discharge current is changed to the parasitic diode. Since the voltage flows into the positive electrode side of the cell group 12 that is the target of voltage detection via 34a, the CPU 17 cannot detect an abnormality.

Therefore, the CPU 17B performs the above-described control to detect that an abnormality has occurred in the cell group 12, which is a voltage detection target, in parallel with the discharge being performed in the cell group 12 on the high potential side. It is possible to do.

(Seventh Embodiment) FIGS. 9 and 10 show a seventh embodiment of the present invention. The same parts as those of the third embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only different parts will be described. In the seventh embodiment, an abnormality detection unit 13E is used. Referring to FIG. 10, in the abnormality detection unit 13E, both of the FETs 34 and 42 serving as the cutoff switching elements are deleted.
The resistor 33 of the detection voltage changing means 35 is also omitted.

The collector of the transistor 32 is
It is connected to the negative terminal of the cell group 12 via a series circuit of a diode 52 and a resistor 33. Diode 5
2 and the resistor 33 are connected to the abnormality detection unit 13
It is connected to the output terminal 13Eb for detecting abnormality of E.
Note that a diode 52 and a resistor 5
The addition of 3 constitutes the detection voltage changing means 54.

Here, referring to FIG. 9, the output terminal 13
Eb is connected via a harness 55 to an input terminal 18Cb of the ECU 18C, and the input terminal 18Cb is connected to a non-inverting input terminal of a voltage detector (voltage detecting means) 56 dedicated to abnormality detection. The inverting input terminal of the voltage detector 56 is connected to the input terminal 18Ca corresponding to the cell group 12 on the low potential side.

The output terminal of each voltage detector 56 is connected to the input terminal of another multiplexer 57.
The input signal selected by the PU (abnormality detection means, discharge control means) 17C is output to the A / D converter 16.

Next, the operation of the seventh embodiment will be described. The CPU 17C uses the voltage detector 14 only for monitoring the terminal voltage in order to equalize the terminal voltage between the cell groups 12, and uses the voltage detector 56 for the abnormality determination of the cell group 12. Has become. That is,
When the cell group 12 is in a normal state, the transistor 2
4, 28 and 32 are all in the off state,
Is approximately 0 V. If the output signal level of the voltage detector 56 read via the multiplexer 57 and the A / D converter 16 is approximately 0 V, the CPU 17C
The corresponding cell group 12 is determined to be normal.

When any one of the unit cells 11 in the cell group 12 (1) is overcharged as in the first embodiment, for example, the transistor 24 is turned on, and the transistors 28 and 32 are also turned on. Becomes
Then, a current flows through the resistor 53 via the diode 52, so that the potential difference between both ends thereof becomes substantially equal to the terminal voltage of the cell group 12 (1). Therefore, the CPU 17C
If the read output signal level of the voltage detector 56 corresponds to the terminal voltage of the cell group 12 (1), it is determined that an abnormality has occurred in the cell group 12 (1).

As described above, according to the seventh embodiment, the CPU
17C uses the voltage detector 14 only for monitoring the terminal voltage of the cell group 12, and uses the dedicated voltage detector 56 for the abnormality determination of the cell group 12.
At the same time as discharging any one of the cell groups 12 in order to equalize the terminal voltage between the cell groups 12, even if an abnormality occurs in any one of the cell groups 12,
Abnormality determination can be performed without any problem.

The present invention is not limited to the embodiment described above and shown in the drawings, and the following modifications or extensions are possible. The number of unit cells connected in series per cell group is not limited to “4”. As the number of series connections increases, the total number of cell groups decreases, so the number of output voltage detections on the control unit side decreases.On the other hand, since the output voltage of the cell groups increases, components with a higher withstand voltage are used. Required. Therefore, the number of series connections may be appropriately set in consideration of a cost determined by a trade-off between the two. For example, assuming that the power supply is constituted by general-purpose electronic components which are not specifically designed to have a high withstand voltage specification, it is preferable to suppress the output voltage of the cell group to about 20V. Therefore, as in the above embodiment, the unit cell has a maximum voltage of 4.2.
In the case of a lithium battery of about V, 4-5 series is considered to be appropriate. Further, the number of cell groups connected in series is not limited to “20”, and may be appropriately set according to the output voltage required for the assembled battery.

In the first or second embodiment, the voltage detector 14 is arranged inside the abnormality detection unit 13 and the output signal of the voltage detector 14 is sent to the ECU via the harness 36.
18 may be given. For example, in the first embodiment, the FET 34 may be omitted, the non-inverting input terminal of the voltage detector 14 may be connected to the collector of the transistor 32, and a change in the collector voltage may be detected. Further, it may be connected to the cathode of the diode 25 (A) of the detection voltage changing means 35. In this case, if the cell group 12 is normal,
The detection voltage is 0 V, and the detection voltage increases as the unit cell 11 in which the abnormality has occurred becomes higher in potential. It may be determined which unit cell 11 has an abnormality according to the voltage difference. The configuration corresponding to the detection of the overcharged state of the unit cell 11 in the first embodiment and the configuration corresponding to the detection of the overdischarged state of the unit cell 11 in the second embodiment are first and second means, The first and second elements may be provided in parallel. With such a configuration, any one of the unit cells 11
Can be detected both when the battery is overcharged and when it is overdischarged. In this case, two switching elements for cutoff may be provided correspondingly, or one FET 34 may be turned on / off by, for example, taking the OR (negative logic input) of each voltage conversion signal. good.

Further, in the seventh embodiment, the resistor 53 and the voltage detector 56 may be arranged inside the abnormality detecting unit 13. Abnormality detection units 13B-1 after the third embodiment
3E may be replaced with the abnormality detection unit 13A of the second embodiment. The switching element for interruption is MOS
Instead of the FETs 34 and 42 and the relay switch 47, bipolar transistors and other analog switches may be used. Further, the detection switching element is not limited to the bipolar transistor 24 but may be a MOS transistor.
An FET may be used. The reference voltage generating means is not limited to the one configured by the Zener diode 21, but may be configured by using, for example, a band gap reference.
With such a configuration, it is possible to easily cope with the upper limit voltage or the lower limit voltage set for various unit cells similarly to the Zener diode 21 by appropriately selecting the reference voltage at which the band gap reference is generated. .
In addition, the accuracy of the reference voltage can be improved by reducing the fluctuation of the reference voltage, and the power consumption of the reference voltage generating means can be further reduced.

The unit cell is not limited to a lithium battery, but can be similarly applied to a lead battery or a nickel-based battery. The on-voltage supply means may be provided for at least one or more unit cells 11 constituting the cell group 12. It is not limited to electric vehicles and HEVs, but is also constructed by connecting a plurality of unit cells in series, such as small consumer devices such as notebook personal computers and portable VTRs, and secondary battery facilities for power storage. Any battery that uses a battery can be applied.

[Brief description of the drawings]

FIG. 1 is a first embodiment in which the present invention is applied to a hybrid electric vehicle, and is a diagram showing an overall electric configuration.

FIG. 2 is a diagram showing a detailed electrical configuration of an abnormality detection unit.

FIG. 3 is a view corresponding to FIG. 2, showing a second embodiment of the present invention;

FIG. 4 is a view corresponding to FIG. 1, showing a third embodiment of the present invention;

FIG. 5 is a view corresponding to FIG. 2 showing a fourth embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 1 showing a fifth embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 1, showing a sixth embodiment of the present invention;

FIG. 8 is a timing chart showing execution timings of (a) discharge control and (b) abnormality determination processing of a cell group executed by a CPU.

FIG. 9 is a view corresponding to FIG. 1, showing a seventh embodiment of the present invention.

FIG. 10 is a diagram corresponding to FIG. 2;

FIG. 11 is a diagram corresponding to FIG. 1 showing a conventional technique.

[Explanation of symbols]

11 is a unit cell, 12 is a cell group, 13, 13A,
13B, 13C, 13D and 13E are abnormality detection units, 14 is a voltage detector (voltage detection means), 15 is a multiplexer (voltage detection means), 16 is an A / D converter (voltage detection means), and 17 is a CPU (abnormality judgment). Means), 1
7A, 17B, 17C are CPUs (abnormality determining means, discharge control means), 19 is a battery pack, 20 is a resistor, 21 is a Zener diode (reference voltage generating means), 22 is a series circuit (ON voltage supply means), and 24 is A transistor (switching element for detection); 34, a P-channel MOSFET (switching element for disconnection); 35, 35 'detection voltage changing means; 37, a zener diode (reference voltage generating means);
38 is a series circuit (ON voltage supply means), 39 is a detection voltage changing means, 42 is a P-channel MOSFET (switching element for disconnection), 44 is a discharge resistor, 45 is a discharge circuit (discharge means), and 47 is a relay switch (disconnect). Switching element), 51 is a discharge path forming means, 54 is a detected voltage changing means, and 56 is a voltage detector (voltage detecting means).

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2G016 CA03 CB12 CB31 CC01 CC04 CC16 CC27 CD04 CD06 CD09 CD14 5G003 AA07 BA03 DA07 EA08 FA04 FA06 GA01 GC05 5G053 AA09 BA04 DA03 EA01 FA05 5H030 AA09 AS08 BB01 BB26 FF43

Claims (18)

[Claims] 1. A battery pack comprising a plurality of unit cells each comprising a secondary battery connected in series to form a cell group, and a plurality of the cell groups connected in series to be used for an assembled battery. When the terminal voltage of the unit cell exceeds the upper limit voltage,
ON voltage supply means configured to supply a predetermined ON voltage to the detection switching element; detection voltage change means for changing the detection voltage when the detection switching element is turned on; Voltage detecting means for detecting a change in voltage associated with a change in the on / off state of the switching element, and a voltage detected by the voltage detecting means.
An abnormality detection device for an assembled battery, comprising: abnormality determination means for detecting that an abnormality has occurred in the cell group. 2. A battery pack formed by connecting a plurality of unit cells each composed of a secondary battery in series to form a cell group, and connecting the plurality of cell groups in series. When the terminal voltage of the unit cell is equal to or higher than the lower limit voltage,
ON voltage supply means configured to supply a predetermined ON voltage to the detection switching element; detection voltage changing means for changing the detection voltage when the detection switching element is turned off; Voltage detecting means for detecting a change in voltage associated with a change in the on / off state of the switching element, and a voltage detected by the voltage detecting means.
An abnormality detection device for an assembled battery, comprising: abnormality determination means for detecting that an abnormality has occurred in the cell group. 3. A cell group formed by connecting a plurality of unit cells each composed of a secondary battery in series to form a cell group, and used for an assembled battery formed by connecting a plurality of cell groups in series. When the terminal voltage of the unit cell exceeds the upper limit voltage,
First on-voltage supply means configured to supply a predetermined on-voltage to the first detection switching element; and when a terminal voltage of the unit cell is equal to or higher than a lower limit voltage,
A second on-voltage supply unit configured to supply a predetermined on-voltage to the second detection switching element; and a first on-voltage changing unit configured to change the detection voltage when the first detection switching element is turned on. Detecting voltage changing means, second detecting voltage changing means for changing a detecting voltage when the second detecting switching element is turned off, and changing on / off state of the first or second detecting switching element. Voltage detecting means for detecting a change in voltage associated with the operation, and a voltage detected by the voltage detecting means.
An abnormality detection device for an assembled battery, comprising: abnormality determination means for detecting that an abnormality has occurred in the cell group. 4. A switching element for shutting off a voltage output of a cell group when a detection voltage is changed by the detection voltage changing means, wherein the voltage detecting means is provided by the switching element for cutoff. 4. The abnormality detecting device for a battery pack according to claim 1, wherein a change in voltage caused by interruption of the voltage output of the cell group is detected. 5. The device according to claim 1, wherein the switching element for detection and the on-voltage supply unit are arranged for all of the unit cells constituting the cell group. An abnormality detection device for assembled batteries. 6. The on-voltage supply means is constituted by a series circuit of a resistor connected in parallel to the unit cell and a reference voltage generation means for generating a predetermined reference voltage. 6. A predetermined on-voltage is supplied to the switching element.
An abnormality detection device for a battery pack according to any one of the above. 7. The abnormality detecting device for an assembled battery according to claim 6, wherein said reference voltage generating means comprises a Zener diode. 8. The battery pack abnormality detecting device according to claim 6, wherein said reference voltage generating means comprises a band gap reference. 9. The abnormality detecting device for an assembled battery according to claim 1, wherein said switching element for detection is constituted by a bipolar transistor. 10. The battery pack abnormality detecting device according to claim 1, wherein said detection voltage changing means is configured using a bipolar transistor. 11. The switching device according to claim 1, wherein the switching element comprises a MOSFET disposed between the positive electrode side of the cell group and the voltage detecting means. An abnormality detection device for an assembled battery according to the above. 12. A parallel connection to each cell group,
The abnormality of the battery pack according to any one of claims 1 to 10, further comprising a discharge unit configured to perform a discharge through a discharge resistor so as to adjust a variation in a terminal voltage between each cell group. Detection device. 13. The switching element for shutting off is constituted by a MOSFET arranged between a positive electrode side of a cell group and the voltage detecting means, and the voltage detecting means detects a voltage for any one of the cell groups. 13. The battery pack according to claim 12, further comprising: discharge control means for controlling so as to prohibit discharge by the discharge means of the cell group arranged on the high potential side of the cell group during the detection. Anomaly detection device. 14. The shut-off switching element is constituted by a MOSFET arranged between a positive electrode side of a cell group and the voltage detecting means, and the shut-off switching element is arranged in any one of the cell groups. When the switching element is turned off, and when discharging is performed by the discharging means in the cell group arranged on the high potential side of the cell group, the discharge current is changed to the former cell group. And forming a discharge path leading to the negative electrode side, and dividing the series terminal voltage of the former cell group and the cell group arranged on the high potential side together with the discharge resistance of the discharge means by a voltage dividing resistor. 13. The abnormality detection device for a battery pack according to claim 12, further comprising a discharge path forming means provided in the discharge path. 15. The shut-off switching element is composed of two MOSFETs connected in opposite directions between a positive electrode side of a cell group and the voltage detecting means, and the detection voltage is changed by the detection voltage changing means. 13. The abnormality detecting device for a battery pack according to claim 12, wherein both the devices are turned off at the same time in a case where the error is detected. 16. An abnormality detection unit including the detection switching element, the on-voltage supply unit, the detection voltage changing unit, and the cutoff switching element, wherein the abnormality detection unit has an operation power supply from a corresponding cell group. 16. Supply as claimed in claim 1 to 15
An abnormality detection device for a battery pack according to any one of the above. 17. The apparatus according to claim 1, wherein the unit cell is a lithium battery. 18. The battery pack abnormality detecting device according to claim 1, wherein the battery pack is used as a driving battery of an electric vehicle or a hybrid electric vehicle.