JPH0915311A - Failure detection device for battery set - Google Patents

Abstract

PURPOSE: To provide a failure detection device for a battery set which surely detects failure caused by over discharge, etc., without affected by variability in terminal voltage due to deterioration of a cell at charging/discharging by measuring the terminal voltage of module battery, more than two minutes after main charge/discharge, when the terminal voltage of each cell is stable. CONSTITUTION: A measuring part 6a, measuring terminal voltage of each module battery 2 when more than two minutes passed after main charge/discharge of a battery set 1 was finished, is provided to a detection unit 6. And an estimation part 6b which finds an average value or a maximum value of the terminal voltage, used as reference voltage, is provided. And further, a judgment part 6c, which judges it as failure when difference between the reference voltage and each terminal voltage is higher than 1V, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detection device for detecting a module battery including a unit cell in which a failure such as over-discharging has occurred in an assembled battery mounted on an electric vehicle or the like.

[0002]

2. Description of the Related Art As batteries for electric vehicles, assembled batteries such as nickel-cadmium batteries, nickel-metal hydride batteries or lead acid batteries are used. This assembled battery is obtained by combining a plurality of module batteries in which a plurality of unit cells (corresponding to a unit cell in the case of a lead storage battery) are connected in series to obtain a predetermined voltage.

By the way, in nickel-cadmium batteries, nickel-metal hydride batteries, etc., when they are repeatedly over-discharged, a dry-up phenomenon occurs due to the loss of the electrolytic solution, and when a minute short circuit or dead short occurs, heat is generated. Problem arises. Therefore, detecting the occurrence of such a failure,
Immediate measures such as battery replacement should be taken. When such a failure as over discharge occurs in each of the unit cells constituting the assembled battery, the terminal voltage drops abnormally. However, the terminal voltage of the unit cell varies depending on the temperature environment, the depth of discharge, and the like even when the unit cell is normal. Therefore, even if only the terminal voltage of the whole assembled battery is measured, it is not possible to immediately determine whether or not this terminal voltage is abnormal. That is, in order to detect an abnormality in the terminal voltage due to a failure, it is necessary to compare the terminal voltage of the failed cell with the terminal voltage of another normal cell under the same environment and under the same use condition. Moreover, such a situation also applies when a failure occurs in the lead storage battery.

Therefore, various detection devices have been proposed in the past, which detect an abnormality by measuring the terminal voltage of each unit cell or each module battery that constitutes an assembled battery and comparing these terminal voltages with each other. For example, Japanese Patent Application No. 58-53
The detecting device proposed in No. 187 measures the terminal voltage of each battery cell or each module battery during charging, and when the difference between the maximum value and the minimum value of these terminal voltages is more than a predetermined value. Judge as abnormal. Also, JP-A-55-1132
The detection device described in Japanese Patent Publication No. 77 is for measuring the terminal voltage of each module battery during charging and discharging or under no load, and the difference between these terminal voltages or the difference between the highest value and the lowest value is a predetermined value or more. If it becomes, it is determined to be abnormal. Furthermore, JP-A-57
The detection device described in Japanese Patent Laid-Open No. -105975 measures the terminal voltage of each cell during charging / discharging, and when the difference from the average value of these terminal voltages exceeds a predetermined value, it is determined to be abnormal. To do. Further, the detection device described in JP-A-58-97273 determines that an abnormality occurs when the standard deviation or variance of the terminal voltage of each module battery exceeds a predetermined value.

[0005]

However, the unit cell is
If the battery capacity decreases according to the individual difference of each cell due to deterioration due to use, the terminal voltage of some cells may drop significantly during charging / discharging than during failure. It becomes difficult to distinguish between a drop in terminal voltage and a drop in terminal voltage due to a failure. However,
Since the conventional detection device measures the terminal voltage of a single battery or a module battery in which these are connected in series even during charging / discharging, if the terminal voltage of a normal single battery that has deteriorated to some extent during charging / discharging drops significantly. There is a problem in that an abnormality may be erroneously determined. That is, the conventional detection device is
Rather than detecting the failure of individual cells, the main purpose is to determine the end of life by detecting the occurrence of large variations in the terminal voltage during charging and discharging due to deterioration of each cell. It was

Further, the terminal voltage of each unit cell or module battery is usually measured sequentially by scanning over a time of about several milliseconds, so that a discharge current intermittently flows in a pulsed manner like in an electric vehicle. In this case, there may be a large difference in the state of the discharge current between the first measurement and the last measurement, and the measurement conditions of the terminal voltage are different, which may cause an erroneous determination.

Further, when the conventional detection device measures the terminal voltage for each unit cell, if a large number of unit cells are used, such as an assembled battery used in an electric vehicle, it will be very large for the measurement. There is also a problem that a large amount of distribution lines are required, the space between the individual cells is blocked by the distribution lines, heat dissipation becomes insufficient, and high voltage measures between a large number of distribution lines are required.

The present invention has been made in view of the above circumstances, and measures the terminal voltage of a module battery when charging / discharging is completed and the terminal voltage of each cell is stable, so that overdischarge and the like can be prevented. It is an object of the present invention to provide an assembled battery failure detection device capable of reliably detecting only an abnormality in a terminal voltage due to a failure.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to an assembled battery in which a plurality of module batteries in which a plurality of unit cells are connected in series are further combined and connected to each other. Terminal voltage measuring means for measuring the terminal voltage of each module battery after a lapse of a predetermined time from the end of charging and / or discharging, and calculation using the terminal voltage of each module battery measured by this terminal voltage measuring means as a parameter The reference voltage estimating means for estimating the reference voltage, and the difference between the reference voltage estimated by the reference voltage estimating means and the terminal voltage of each module battery measured by the terminal voltage measuring means, respectively, and these differences are set to a predetermined value. A failure determination means for determining that the unit cell has failed when the value exceeds the value is provided.

Also, in an assembled battery in which a plurality of module batteries in which a plurality of nickel-cadmium batteries or nickel-metal hydride batteries are connected in series are further combined and connected, the main charging and / or
Alternatively, a terminal voltage measuring means for measuring the terminal voltage of each module battery after a lapse of a predetermined time of 2 minutes or more after the end of discharging, and the maximum value or the average of the terminal voltage of each module battery measured by the terminal voltage measuring means. A reference voltage estimating means for estimating the value as a reference voltage, and a difference between the reference voltage estimated by the reference voltage estimating means and the terminal voltage of each module battery measured by the terminal voltage measuring means, respectively, and the difference between them is 1V. And a failure determination means for determining that the unit cell has failed.

[0011]

According to the function, the terminal voltage measuring means measures the terminal voltage of each module battery after a lapse of a predetermined time after the main charging and / or discharging of the assembled battery is completed. Here, even if the normal unit cell has a variation in the terminal voltage during charging / discharging due to deterioration to the extent that it does not reach the end of its life, if this charging / discharging ends, time will elapse. Along with this, the terminal voltage recovers to a substantially uniform value and stabilizes. Therefore, if all the unit cells are normal, even if some of them are deteriorated to some extent, the terminal voltage measured by the terminal voltage measuring means has almost no variation.

However, when a failure occurs in the unit cell due to over-discharging, the terminal voltage delays in recovering to the normal level of the unit cell even after charging / discharging is completed. Further, when a failure occurs due to a minute short circuit, the terminal voltage of the unit cell gradually decreases after the end of charging / discharging. Furthermore, when a failure due to a dead short circuit occurs, the voltage of the unit cell after charging / discharging becomes 0V. Therefore, the terminal voltage of the module battery including the unit cell in which these failures occur is reduced to some extent as compared with the terminal voltage of the module battery including only the normal unit cell even after a predetermined time has elapsed since the end of charging / discharging. It will be what you did.

Therefore, if the reference voltage estimating means estimates the reference voltage based on the terminal voltage of each module battery, and the failure determining means calculates the difference between the terminal voltage of each module battery and the reference voltage, Since only the difference with the terminal voltage of the module battery including the unit cell in which the failure has occurred becomes large, it can be determined that the unit cell of the module battery has failed when this difference exceeds a predetermined value.

The main charging and / or discharging means charging from an external power source or the like and discharging for supplying electric power to a main load such as a motor, and supply of minute electric power to an instrument or the like. The discharge for is excluded. Further, in the case of an electric vehicle or the like, electric power is supplied to the motor during acceleration, and regenerative braking is performed when engine braking is used.
The main charging and discharging also includes the case of charging and discharging by repeating the discharging by the supply of the electric power and the charging by the regenerative braking. Whether or not the main charging and / or discharging is performed can be determined by whether or not the charge / discharge current is a predetermined value or more.

Further, the calculation using the terminal voltage of each module battery as a parameter by the reference voltage estimating means may be a calculation for estimating the terminal voltage of the module battery composed of only normal cells under the same conditions at the time of measurement. However, any calculation may be used.

According to the above means, a nickel-cadmium battery or a nickel-metal hydride battery is used as the unit cell, and the predetermined time in the terminal voltage measuring means is set to 2 minutes or more, and the reference In the nickel-cadmium battery or the nickel-metal hydride battery, the reference voltage estimated by the voltage estimating means is set to the maximum value or the average value of the terminal voltage of each module battery and the predetermined value in the failure determining means is set to 1V. Provided is a failure detection device that is most suitable for detecting failures such as over-discharge, micro short circuit, or dead short circuit.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 10 show an embodiment of the present invention. FIG. 1 is a block diagram showing the structure of a failure detecting device for an assembled battery, and FIG. 2 is a terminal of a normal cell at the time of discharging. 3 is a time chart showing a change in voltage, FIG. 3 is a time chart showing a change in a terminal voltage of a normal module battery at the time of discharging, and FIG. 4 is a time chart showing a change in a terminal voltage of an over-discharged cell at the time of discharging. 5, FIG. 5 is a time chart showing a change in the terminal voltage of a unit cell in which a micro short circuit occurs during discharging, FIG. 6 is a time chart showing a change in the terminal voltage of a unit cell in which a micro short circuit occurs during charging, and FIG. A time chart showing a change in terminal voltage of a unit cell in which a dead short circuit occurs during discharging, and FIG. 8 shows a change in terminal voltage of a unit cell in which a dead short circuit occurs during charging. Im chart, Figure 9 showing the difference of the terminal voltage of each module battery during discharge, FIG. 10
FIG. 4 is a diagram showing a difference in terminal voltage of each module battery during charging.

In this embodiment, a failure detecting device for an assembled battery mounted on an electric vehicle will be described. As shown in FIG.
The assembled battery 1 further comprises 20 module batteries 2 connected in series, each of which is a unit cell 2a of 10 cells. A rectangular nickel-cadmium battery is used as the unit cell 2a. And the module battery 2
Shows that 10 unit cells 2a are housed in a holder (not shown) and connected in series. The battery pack 1 supplies power to the motor 4 via the controller 3. The motor 4 is a drive device for running the electric vehicle, and the controller 3 is a battery pack 1 that is supplied to the motor 4 according to the operation of the driver of the electric vehicle.
It is a circuit that controls the power supply from. Also, this battery pack 1
Also supplies power to instruments such as a remaining capacity meter (not shown).

The bipolar terminals of each module battery 2 are connected to a detection unit 6 via a detection scanning circuit 5. The detection scanning circuit 5 is composed of two contactless relays 1
This is a circuit in which 20 sets of switches 5a and 5b operating at the same time are provided corresponding to 20 module batteries 2, and the switches 5a and 5b of each set are sequentially operated by a scanning signal sent from the detection unit 6. Scanning is performed by conducting the electric current once. The positive terminals of each module battery 2 are connected to the positive input of the detection scanning circuit 5 through the corresponding switches 5a of each set, and then connected to the positive input of the detection scanning circuit 5.
The negative terminal of the switch 5b corresponds to each set of switches 5b.
And is connected to the negative input of the detection scanning circuit 5 after being connected via the. Therefore, the detection unit 6 sends a scanning signal to the detection scanning circuit 5 to scan while sequentially switching the terminal voltage of each module battery 2 of the assembled battery 1 and sequentially inputs the data over a period of several milliseconds. It will be. A current transformer 7 for detecting a charging / discharging current flowing in the battery pack 1 is provided on a distribution line extending from the battery pack 1 to the controller 3 and the like. The detection output of 7 is also input.

The detection unit 6 is a control arithmetic circuit such as a microcomputer which operates by receiving power supply from an auxiliary machine 8 which is a battery different from the assembled battery 1. The detection unit 6 includes a measuring unit 6a that measures the terminal voltage of each of the module batteries 2 and an estimating unit 6b that obtains the average value of the terminal voltages of all the module batteries 2 or the highest value among them as the reference voltage. The reference voltage is compared with the terminal voltage of each module battery 2 to determine a failure.

The measuring unit 6a constantly monitors the charging / discharging current of the battery pack 1 by the current transformer 7, and when the state in which the charging / discharging current is below a predetermined value continues for a predetermined time, a scanning signal is sent to the detection scanning circuit 5. To perform a scan. When this scanning is executed, the terminal voltage of each module battery 2 is changed to A
The data are sequentially input via a D converter or the like and temporarily stored in a storage device such as a RAM. Here, a discharge current to be supplied to the motor 4 at the time of acceleration during traveling of the electric vehicle, and a charging current due to regenerative braking flow into the assembled battery 1 when engine braking is used. Further, when charging is performed at a charging stand or the like, a charging current from an external power source flows in. Further, in the battery pack 1, a weak discharge current of the order of mA always flows as a dark current in order to supply power to meters such as a remaining capacity meter. The measuring unit 6a has a current value that is sufficiently lower than the charging / discharging current during acceleration such as during traveling or during charging, and that is sufficiently higher than the weak discharge current that flows as dark current. When a predetermined value is set and the charging / discharging current of the assembled battery 1 exceeds the predetermined value, it is detected that main charging or discharging or charging / discharging is being performed. Then, when the charging / discharging current of the assembled battery 1 becomes less than or equal to a predetermined value and only a weak dark current flows, a timer is started, and when a predetermined time elapses without the charging / discharging current exceeding this predetermined value, the detection scanning circuit 5 To send a scan signal to. This predetermined time is set to a sufficient time until the terminal voltages reach a stable and substantially uniform voltage even when the terminal voltages of the normal cell 2a vary due to differences in capacity and the like during charging and discharging. To be done. For example, in the case of a nickel-cadmium battery or a nickel-metal hydride battery, it takes about 2 minutes for the terminal voltage to stabilize, so in this embodiment, this predetermined time is set to 2 minutes or longer.

The estimating unit 6b reads the terminal voltages of all the module batteries 2 stored by the measuring unit 6a, obtains an average value or a maximum value thereof, and stores the average value or the maximum value as a reference voltage in a RAM or the like. Once stored in the device. The stable terminal voltage of the module battery 2 varies depending on the environment and use conditions even when all the unit cells 2a are normal. Therefore, the estimation unit 6b performs a calculation based on the actual terminal voltage measured by the measurement unit 6a in this manner, and thus a normal single battery under the same environment and the same use condition as the target assembled battery 1 The terminal voltage of the module battery 2 including only 2a is estimated as the reference voltage. Therefore, this reference voltage is the normal module battery 2
If it is to be estimated as the terminal voltage of, it is not limited to the average value (arithmetic average or arithmetic average) or the maximum value, but it is obtained by other calculation such as the average value excluding the median or the minimum value. May be

The determination unit 6c sequentially reads the terminal voltage of each module battery 2 stored in the measurement unit 6a, and calculates the difference between this terminal voltage and the reference voltage stored in the estimation unit 6b. It is judged whether or not each exceeds. When it is determined that the difference between the terminal voltage and the reference voltage exceeds a predetermined value, it is determined that the unit cell 2a included in the module battery 2 having the terminal voltage has a failure, and for example, a display device (not shown) Issue a warning to etc. In the case of a nickel-cadmium battery, a nickel-metal hydride battery, or the like, the rated value of the unit cell 2a is 1.2V, so it is appropriate to set the predetermined value to about 1V.

Normal cell 2a constituting the above-mentioned assembled battery 1
FIG. 2 shows the changes in the terminal voltage during the main discharge of. However, here, changes in the terminal voltages of the four unit cells A to D are shown. 3 cells A with almost no deterioration
In C to C, the terminal voltage gradually decreases as the remaining capacity decreases during discharge. At this time, although there is some individual difference in the degree of decrease in the terminal voltage, the difference is slight. And
After discharging, the terminal voltage gradually rises, and after 2 minutes, all the cells A to C have a rated voltage of 1.2V.
Almost recovers and stabilizes. However, in the case of the unit cell D that has deteriorated to some extent, the battery capacity has decreased, and therefore the terminal voltage sharply decreases when the remaining capacity almost disappears during discharging. However, when the discharge is completed, this terminal voltage also rises rapidly, and after 2 minutes, the unit cells A to C are discharged.
Same as 1.2V, it recovers and stabilizes. In addition, even when the dark current continues to flow after the end of the main discharge, the dark current is only a weak discharge current on the order of mA, so that the terminal voltages of the unit cells A to E are almost the same after 2 minutes. Stabilize.

Therefore, also in the module battery 2 in which ten normal cells 2a are connected in series, as shown in FIG. 3, the terminal voltage decreases at the time of the main discharge, but the terminal voltage rises at the end of the discharge. It recovers and stabilizes up to the rated voltage of 12V. However, here also, the changes in the terminal voltages of the four module batteries E to H are shown. The degree of reduction in the terminal voltage during discharge of these four module batteries E to H differs depending on the progress of deterioration of each unit cell 2a forming each module battery 2. In addition, here, the terminal voltage of the three module batteries E to G gradually decreases, but the terminal voltage of the one module battery H rapidly decreases. Therefore, at the end of discharging, the difference between the terminal voltages of the module battery E and the module battery H is close to 2V, and even slightly after that, there is a difference of 1V or more.
However, the terminal voltage of this module battery H is not equal to that of the other module batteries E to G after 2 minutes have elapsed from the end of discharging.
It recovers up to 12V, which is the same as, and there is almost no difference between them.

However, when over-discharging occurs in the unit cell 2a, as shown in FIG. 4, the terminal voltage drops to a negative voltage of -1V at the time of main discharge, and becomes 0V when the discharge ends.
It recovers to a certain extent immediately, but recovery to a higher voltage becomes slower. That is, the terminal voltage of the unit cell 2a in which over-discharging has occurred has a difference of 1 V or more from the normal terminal voltage of the unit cell 2a even after 2 minutes have elapsed from the end of discharging.

When a minute short circuit occurs between the positive and negative electrodes inside the unit cell 2a via the separator, as shown in FIG. 5, a large discharge current flows during the main discharge, so that the terminal voltage is normal. However, the terminal voltage gradually decreases to around 0V due to an internal short-circuit current after the end of discharge. As shown in FIG. 6, the unit cell 2a having such a micro short circuit has a fully charged terminal voltage of 1. when the main cell is charged, as shown in FIG. Although it reaches about 5V, the terminal voltage gradually decreases to around 0V due to an internal short-circuit current after the end of charging. That is, in the case of a micro short circuit, when a time of 2 minutes or more elapses after the end of charging / discharging, the normal cell 2
The difference from the terminal voltage of a reaches 1 V or more.

Furthermore, when a dead short circuit occurs in which the positive and negative electrodes inside the unit cell 2a are completely short-circuited, as shown in FIG. 7, the terminal voltage becomes negative voltage -1 V or more due to polarization during the main discharge, and the discharge occurs. Immediately after completion, it returns to 0V. Then, as shown in FIG. 8, the terminal voltage of the unit cell 2a in which such a dead short has occurred is approximately 0 V both during and after the main charging. That is, in the case of a dead short circuit, there is a difference of 1 V or more from the normal terminal voltage of the unit cell 2a even after 2 minutes have elapsed since the end of charging / discharging.

As a result, the terminal voltage of each module battery 2 is 1 V or more depending on the degree of deterioration of each battery cell 2a during or immediately after the main discharge even when all the battery cells 2a are normal. The voltage may vary. However, in the case of the module battery 2 including only the normal unit cells 2a, the terminal voltage becomes stable and there is almost no variation when a time of 2 minutes or more has elapsed after the end of discharging. On the other hand, in the module battery 2 including the unit cell 2a in which over-discharging or dead short circuit has occurred, the terminal voltage does not recover even after a lapse of time of 2 minutes or more after the end of discharging, and the normal unit cell The voltage is 1 V or more lower than the terminal voltage of the module battery 2 having only 2a. In addition, the terminal voltage of the module battery 2 including the unit cell 2a in which the micro short circuit has occurred is the same as the terminal voltage of the normal unit battery 2a only during or immediately after the main discharge and during or immediately after the main charge. There is almost no difference, but if a sufficient time of 2 minutes or more has elapsed from the end of charging / discharging, the normal cell 2a
The voltage becomes 1 V or more lower than the terminal voltage of the module battery 2 only.

The failure detecting apparatus of the present embodiment measures the terminal voltage of each module battery 2 after 2 minutes or more has elapsed since the main charging / discharging of the measuring unit 6a of the detecting unit 6 was completed. When the difference between the terminal voltage and the reference voltage exceeds 1 V, it is determined as a failure. Therefore, the failure due to over-discharge, a minute short circuit or a dead short circuit is generated without being affected by the degree of deterioration of each cell 2a. The module battery 2 including the battery 2a can be reliably detected. On the other hand, for example, when the terminal voltage of each module battery 2 is detected immediately after the main discharge is completed, the module battery 2 including the deteriorated normal cell 2a may be erroneously determined as a failure. In addition, there may occur a case where a failure of the unit cell 2a in which a micro short circuit has occurred is missed.

Table 1 and FIG. 9 show specific examples of the difference between the respective voltage values when the terminal voltage of each of the 20 module batteries 2 is measured immediately after the end of discharge and when it is measured 2 minutes after the end of discharge.

[Table 1] In this case, immediately after the end of discharge, the terminal voltage of each module battery 2 greatly varies, and the module number is 3, 5, and 13 against the average value of 10.0 V. The terminal voltage of the module battery 2 of 1 has a difference of 1V, and the terminal voltage of many module batteries 2 has a difference of 1V or more with respect to the maximum value of 11.0V. However, the terminal voltage of most of the module batteries 2 is 12.0 after 2 minutes from the end of discharge.
Only 10.8 V, which is the terminal voltage of the module battery 2 having a module number of 5 and is around V, has a difference of 1 V or more with respect to the average value of 11.9 V and the maximum value of 12.1 V. Therefore, when the failure detection device of the present embodiment is used, it is possible to reliably determine that only the module battery 2 having the module number 5 is in failure.

Table 2 and FIG. 10 show specific examples of the difference between the voltage values when the terminal voltage of each of the 20 module batteries 2 is measured immediately after the end of charging and when it is measured 2 minutes after the end of charging. .

[Table 2] In this case, immediately after the end of charging, the terminal voltage of each module battery 2 greatly varies, and the module number is 4, 5, and 10 against the average value of 15.0V. The terminal voltage of the module battery 2 of 1 has a difference of 1 V or more, and the maximum value of these is 16.0 V.
However, the terminal voltages of many module batteries 2 have a difference of 1 V or more. However, the terminal voltage of most of the module batteries 2 becomes 1 after 2 minutes from the end of charging.
Only 12.6V, which is the terminal voltage of the module battery 2 having a module number of 5 and is around 4.0V, is 1 against the average value of 13.9V and the maximum value of 14.0V.
The difference is V or more. Therefore, also in this case, when the failure detection device of the present embodiment is used, it is possible to reliably determine that only the module battery 2 having the module number 5 is in failure.

When any of the module batteries 2 is determined to be defective as described above, the module battery 2 is replaced with a normal one, or the module battery 2 has failed. Only the unit cell 2a is replaced.

As described above, according to the failure detecting apparatus of the present embodiment, the terminal voltage of each module battery 2 is measured after a lapse of 2 minutes or more after the main charging / discharging is completed, and therefore, Only the module battery 2 including the failed unit cell 2a can be reliably detected without being affected by the degree of deterioration of the unit cell 2a.

The measuring unit 6a of the detection unit 6 requires a time of about several milliseconds for scanning by the detection scanning circuit 5 when measuring the terminal voltages of all the module batteries 2.
Since this measurement is performed at a stable time when the main charging / discharging current stops flowing, even if the measurement timing of each module battery 2 is slightly deviated, there is a possibility that an erroneous determination may occur due to a large difference in the measurement conditions. Disappear.

In the present embodiment, the failure detecting device for the assembled battery 1 used in the electric vehicle has been described, but the present invention can be similarly applied to assembled batteries used in various other devices. In addition, in the present embodiment, a nickel-cadmium battery was used as the unit cell 2a.
A metal hydride battery or other various secondary batteries can also be used. Further, in the present embodiment, the assembled battery 1 is configured by connecting 20 module batteries 2 in series, and each module battery 2 is configured by connecting 10 unit cells 2a in series. However, a plurality of unit cells are connected in series. As long as a plurality of connected module batteries are combined and connected, the assembled battery of any configuration can be similarly implemented. Moreover, an assembled battery can be constructed by connecting a plurality of module batteries in parallel or in series-parallel.
Further, in the present embodiment, the terminal voltage of each module battery 2 is scanned by the detection scanning circuit 5 and measured in order, but it is also possible to configure so that these terminal voltages are measured simultaneously.

[0038]

As is apparent from the above description, according to the battery pack failure detection apparatus of the present invention, the module is provided after a predetermined time has elapsed after the end of charging / discharging and the terminal voltage of each cell has stabilized. Since the terminal voltage of the battery is measured, it is possible to reliably detect only the abnormal terminal voltage due to a failure such as over-discharging without being affected by the variations in the terminal voltage during charging and discharging due to deterioration of the unit cell. Become.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a block diagram showing a configuration of a battery pack failure detection device.

FIG. 2 shows an example of the present invention and is a time chart showing changes in the terminal voltage of a normal cell during discharging.

FIG. 3 shows an embodiment of the present invention and is a time chart showing changes in the terminal voltage of a normal module battery during discharging.

FIG. 4 shows an example of the present invention and is a time chart showing changes in the terminal voltage of a single cell in which over-discharge has occurred during discharging.

FIG. 5 is a time chart showing an embodiment of the present invention and showing a change in terminal voltage of a single cell in which a minute short circuit has occurred during discharging.

FIG. 6 is a time chart showing an embodiment of the present invention and showing a change in terminal voltage of a unit cell in which a micro short circuit occurs during charging.

FIG. 7 shows an example of the present invention and is a time chart showing a change in terminal voltage of a unit cell in which a dead short circuit occurs during discharging.

FIG. 8 shows an example of the present invention and is a time chart showing a change in terminal voltage of a single cell in which a dead short circuit occurs during charging.

FIG. 9 is a diagram showing an example of the present invention and is a diagram showing a difference in terminal voltage of each module battery during discharging.

FIG. 10 is a diagram showing an embodiment of the present invention and is a diagram showing a difference in terminal voltage of each module battery during charging.

[Explanation of symbols]

 1 assembled battery 2 module battery 2a single battery 5 detection scanning circuit 6 detection unit 6a measurement unit 6b estimation unit 6c determination unit

Claims (2)

[Claims] 1. An assembled battery in which a plurality of module batteries in which a plurality of unit cells are connected in series are further combined and connected, and each module battery after a lapse of a predetermined time after main charging and / or discharging of the assembled battery is completed. And a reference voltage estimating means for estimating a reference voltage by performing calculation using the terminal voltage of each module battery measured by the terminal voltage measuring means as a parameter, and the reference voltage estimating means. The difference between the reference voltage estimated by the terminal voltage and the terminal voltage of each module battery measured by the terminal voltage measuring means is respectively calculated, and failure determination means for determining a failure of the single battery when these differences exceed a predetermined value. A battery pack failure detection device characterized by being provided. 2. An assembled battery in which a plurality of module batteries in which a plurality of nickel-cadmium batteries or nickel-metal hydride batteries are connected in series are further combined and connected, and the main charging and / or discharging of the assembled battery is performed. The terminal voltage measuring means for measuring the terminal voltage of each module battery after a lapse of a predetermined time of 2 minutes or more from the completion of the above, and the maximum or average value of the terminal voltage of each module battery measured by this terminal voltage measuring means Reference voltage estimating means for estimating the reference voltage, and a difference between the reference voltage estimated by the reference voltage estimating means and the terminal voltage of each module battery measured by the terminal voltage measuring means are respectively calculated, and the difference exceeds 1V. A failure detection device for an assembled battery, comprising: a failure determination means for determining a failure of a single battery.