JP2002078217A - Abnormality detector for battery pack and battery pack device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an abnormality that may happen in a voltage-detecting system of module batteries that constitute a battery pack. SOLUTION: A residual amount Sn of each module battery is computed based on a detected voltage Vn of each module battery, as well as the rate of change of the residual amount DSn is calculated. (S100 to S104). The abnormality of a voltage-detecting system of the module batteries relating to the rate of change DSn is determined depending on whether the rate of change DSn remains or not within a tolerance range of variations set by multiplying the average value A of the rate of change by a predetermined coefficient a and a predetermined coefficient b. (S106 to S110). The abnormality is determined based on a condition that the rate of change of the residual amount deviates from the tolerance range of variations in a small range or in a large range respectively having a large rate of change of the residual amount, due to the fact that a module battery, of which the voltage is detected by an abnormal voltage-detecting system and is subjected to equalizing process, is slid in the direction with either a large or small residual amount compared with a module battery of which the voltage is detected by a normal voltage-detecting system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery abnormality detecting device and an assembled battery device, and more particularly, to an abnormality detection of an assembled battery formed by connecting a plurality of module batteries composed of at least one unit cell in series. The present invention relates to a device and an assembled battery device including such an assembled battery and an abnormality detecting device for the assembled battery.

[0002]

2. Description of the Related Art Heretofore, as this type of assembled battery device, there has been proposed an assembled battery device which detects a charging / discharging voltage for each module battery and suppresses overcharging, overdischarging, and failure at the time of charging / discharging (eg, for example). And JP-A-5-64377 and JP-A-8-1.
No. 40204). In this device, a plurality of module batteries composed of a plurality of unit cells are connected in series to form an assembled battery, and a voltage at the time of charge / discharge is detected for each module battery at the time of charge / discharge of the assembled battery. .

[0003]

However, in such an assembled battery device, an abnormality occurring in the voltage detection system cannot be detected, and charge / discharge cannot be properly managed when an abnormality occurs in the voltage detection system. . In a battery pack device that equalizes the voltage of each module battery, the voltage of the module battery is equalized even when an abnormality occurs in the voltage detection system, so the module battery may be overdischarged or overcharged. Occurs.

An object of the present invention is to detect an abnormality that may occur in a voltage detection system of a module battery. Further, it is an object of the battery pack device of the present invention to use the battery pack more appropriately even when an abnormality occurs in the voltage detection system of the module battery.

The applicant has proposed a battery module of this type that detects an abnormality in a module battery (Japanese Patent Application No. 9-339123). In this device, the voltage of the module battery is detected, and the abnormality of the module battery is determined based on whether the detected voltage is within an allowable range.

[0006]

Means for Solving the Problems and Actions and Effects Thereof The present invention employs the following means to achieve at least a part of the above object.

An abnormality detecting apparatus for a battery pack according to the present invention comprises a module voltage for detecting a voltage of each of the plurality of module batteries of a battery pack comprising a plurality of module batteries comprising at least one unit cell connected in series. Detecting means;
A battery module abnormality detecting device comprising: an equalizing unit that equalizes the voltage of each module battery based on the detected voltage of each module battery, wherein the remaining capacity of each of the plurality of module batteries is detected. The gist of the present invention is to include a remaining capacity detection unit that performs the operation and an abnormality determination unit that determines an abnormality of the module voltage detection unit based on the detected remaining capacity of each module battery.

In the battery pack abnormality detecting device of the present invention,
An abnormality of the module voltage detecting means can be determined based on the remaining capacity of each module battery detected by the remaining capacity detecting means. The determination of this abnormality is based on the relationship between the remaining capacity of the module battery and the voltage of the module battery.

In the battery pack abnormality detecting device according to the present invention, the abnormality determining means may be a means for determining an abnormality based on a rate of change in the remaining capacity of each module battery.

In the battery abnormality detecting apparatus according to the aspect of the present invention, the abnormality determining means includes a change rate average value calculating means for calculating an average value of a change rate of the remaining capacity of each module battery. When the rate of change of the remaining capacity of the module battery is larger than or smaller than the average value of the rate of change calculated by the means for calculating the average rate of change by a predetermined value or more, the voltage detection system of the module battery among the module battery detection means It may be a means for determining that there is an abnormality. Alternatively, the abnormality determining means includes a change rate average value calculating means for calculating an average value of the change rate of the remaining capacity of each module battery, and the change rate of the remaining capacity of any one of the module batteries is calculated by the change rate average value calculation. The module battery detecting means may determine that the voltage detecting system of the module battery is abnormal when the value is outside a predetermined range including the average value of the change rate calculated by the means.

[0011] The battery pack device of the present invention is a battery pack device having a battery pack formed by connecting a plurality of module batteries each comprising at least one unit cell in series. The gist of the present invention is to include an abnormality detection device for an assembled battery and an equalization restricting means for restricting equalization by the equalization means when an abnormality is detected by the abnormality detection device.

In the battery pack device of the present invention, when an abnormality is detected by the abnormality detecting device, the equalization restricting means regulates the equalization of the voltage of the module battery. , It is possible to suppress the equalization of the voltage of the module battery based on the above. As a result, overdischarge and overcharge of the module battery can be suppressed.

In the battery pack device of the present invention, when an abnormality is detected by the abnormality detecting device, the abnormal-state voltage correcting means for correcting the voltage of the battery module based on the remaining capacity of the battery module relating to the abnormality is provided. It can also be provided. In this case, the assembled battery can be used by using a more probable voltage of the abnormal battery module.

In the battery pack device according to the present invention, when an abnormality is detected by the abnormality detecting device, the remaining capacity of another battery module is adjusted in a direction approaching the remaining capacity of the battery module relating to the abnormality. Adjustment means may be provided. By doing so, it is possible to reduce the variation in the remaining capacity of each module battery.

[0015]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing a configuration of an assembled battery device 20 including a battery pack abnormality detecting device according to an embodiment of the present invention. The battery pack device 20 of the embodiment includes:
As shown, the output terminal is connected to the load 10 by the power line.
And an electronic control unit 40 that manages the assembled battery 21.

The battery pack 21 is configured by connecting a plurality of module batteries 24a to 24n, which are formed by connecting a plurality of cells 22 such as a lithium ion battery in series, in series. Each module battery 24a to 24n has a single cell 2
Cell equalizing circuits 28a to 28n for equalizing the voltage of each unit cell 22 using voltage detection lines 26a to 26n for detecting the voltage of the second cell 2 are attached. Hereinafter, the reference numerals of the respective parts corresponding to the n number of module batteries 24a to 24n are indicated using numerals and subscripts of alphabets a to n.

The electronic control unit 40 is configured as a microprocessor mainly including a CPU 42, and includes a ROM 44 storing a processing program and a RAM 46 temporarily storing data. The electronic control unit 40 is connected to conductive lines 32a to 32n + 1 connected to the connection terminals of the module batteries 24a to 24n. 24a-2
4n voltage can be detected. In the electronic control unit 40, each of the detected module batteries 24a
Battery 24a-2 based on the voltage of
The remaining capacity Sa to Sn of 4n is calculated. Since the calculation of the remaining capacity (SOC) based on the voltage is well known, its description is omitted. In addition, between each of the conductive lines 32a to 32n + 1,
The resistors 34a to 34n and the transistors 36a to 36n are connected in series.
Are connected to the electronic control unit 40 by signal lines 38a to 38n. Therefore, the electronic control unit 40 can turn on / off the transistors 36a to 36n by outputting on / off signals to the signal lines 38a to 38n. The electronic control unit 4
From 0, the assembled battery 21 and the module batteries 24a to 24n
The lighting signal to the indicator 48 which is turned on when the voltage detection system is abnormal is also output.

Next, the operation of the battery pack device 20 of the embodiment configured as described above, particularly the operation of detecting an abnormality in the voltage detection system of the module batteries 24a to 24n and the operation when this abnormality is detected will be described. FIG. 2 is a flowchart illustrating an example of an abnormality detection processing routine executed by the electronic control unit 40 of the battery pack device 20 according to the embodiment.
This routine is repeatedly executed at predetermined time intervals (for example, every hour).

When the abnormality detection routine is executed, the CPU 42 of the electronic control unit 40 first detects the potential difference between the conductive lines 32a to 32n + 1 to detect the voltages Va to Vn of the module batteries 24a to 24n. A process is performed (step S100). Subsequently, based on the detected voltages Va to Vn of the module batteries 24a to 24n, the remaining capacities Sa to of the module batteries 24a to 24n are determined.
Sn is calculated (step S102), and time change rates DSa to DSn of the remaining capacity are calculated using the calculated remaining capacities Sa to Sn and the remaining capacities Sa to Sn calculated when this routine was executed last time. (Step S10
4). Specifically, this is performed by dividing the difference between the current remaining capacity Sa to Sn and the last remaining capacity Sa to Sn by the time interval at which the abnormality detection processing routine is executed.

The rate of change of the remaining capacity with time DSa to DSa
The average value A of n is calculated (step S106). The calculated average value A is multiplied by a predetermined coefficient a or the average value A is multiplied by a predetermined coefficient b.
and n (step S108). Here, the predetermined coefficient a and the predetermined coefficient b are the time change rates DSa to
It is a coefficient that determines the upper and lower limits of the allowable variation from the average value A of DSn, and is determined by the characteristics and specifications of the unit cell 22 and the module batteries 24a to 24n.
The time change rates DSa to DSn of all remaining capacities are average values A.
If the average value A is smaller than the value obtained by multiplying the average coefficient A by the predetermined coefficient b and larger than the value obtained by multiplying the average value A by the predetermined coefficient a, it is determined that no abnormality has occurred in all the voltage detection systems, and this routine ends. On the other hand, when the time change rate DS of any remaining capacity is larger than the average value A multiplied by the predetermined coefficient a or smaller than the average value A multiplied by the predetermined coefficient b, the time change rate of the remaining capacity It is determined that an abnormality has occurred in the voltage detection system of the module battery 24 related to DS, the indicator 48 is turned on (step S110), and this routine ends. Here, the reason why the abnormality of the voltage detection system can be determined based on the time rate of change DS of the remaining capacity is as follows.

FIG. 3 is an explanatory diagram showing an example of the relationship between the remaining capacity of the module battery and the voltage by the normal voltage detection system and the relationship between the remaining capacity of the module battery and the voltage by the abnormal voltage detection system. The abnormal voltage detection system in FIG. 3 detects a higher voltage. In the equalization processing as the processing of step S204 of the equalization processing routine of FIG. 4 described below, the remaining capacities Sa to S of the module batteries 24a to 24n are set.
The transistor 36 is turned on for a module battery having a high voltage so that n becomes equal, and power is consumed by the resistor 34. Therefore, a module battery in which a voltage is detected by an abnormal voltage detection system in which a voltage is detected higher is discharged more than necessary in a module battery, and a module in which a voltage is detected by a normal voltage detection system even if the same voltage is detected. The remaining capacity (SOC) is smaller than that of the battery. As shown, the relationship between the remaining capacity (SOC) and the voltage has a large change rate in a region where the remaining capacity (SOC) is small and in a region where the remaining capacity is large. For this reason, in a region where the remaining capacity (SOC) of the module battery where the voltage is detected by the abnormal voltage detection system is small, the time change rate of the remaining capacity is the remaining capacity of the module battery where the voltage is detected by the normal voltage detection system. In a region where the remaining capacity (SOC) is large, the time change rate of the remaining capacity is larger than the time change rate of the remaining capacity of the module battery whose voltage is detected by the normal voltage detection system. And become smaller.

Conversely, in the module battery in which the voltage is detected by the abnormal voltage detection system in which the voltage is detected lower, the discharge by the equalization processing is not performed. As a result, the remaining capacity (SOC) becomes larger than that of the module battery whose voltage is detected. For this reason, in a region where the remaining capacity (SOC) of the module battery where the voltage is detected by the abnormal voltage detection system is small, the time change rate of the remaining capacity is the remaining capacity of the module battery where the voltage is detected by the normal voltage detection system. In a region where the remaining capacity (SOC) is large, the time change rate of the remaining capacity is smaller than the time change rate of the remaining capacity of the module battery whose voltage is detected by the normal voltage detection system. Then it gets bigger. Using such a concept, in the embodiment, the abnormality of the voltage detection system of the module battery having the time change rate DS exceeding the allowable range including the average value A of the time change rates DSa to DSn of the remaining capacity is determined.

In the battery pack device 20 of the embodiment, in addition to such abnormality detection processing, processing for equalizing the module batteries 24a to 24n is also performed. FIG. 4 is a flowchart illustrating an example of an equalization processing routine executed by the electronic control unit 40 of the battery pack device 20 according to the embodiment. This routine is repeatedly executed every predetermined time (for example, every 30 minutes).

When the equalization processing routine is executed, the CPU 42 of the electronic control unit 40 first detects a potential difference between the conductive lines 32a to 32n + 1 to detect voltages Va to Vn of the module batteries 24a to 24n. A process is performed (step S200). Subsequently, it is determined whether or not the abnormality of the voltage detection system is determined (step S20).
2) If no abnormality is determined, an equalization process is performed so that the remaining capacities Sa to Sn of the module batteries 24a to 24n are equal (step S204), and this routine ends. This equalization process is performed on the high-voltage module batteries so that the remaining capacities Sa to Sn of the module batteries 24a to 24n are equal.
Is turned on and power is consumed by the resistor 34.

On the other hand, when it is determined that the voltage detection system is abnormal, the voltage of the module battery whose voltage is detected by the voltage detection system in which the abnormality has been determined is corrected based on the time change of the remaining capacity (step S206). Then, the voltage of each of the module batteries 24a to 24n is adjusted so as to approach the corrected voltage (step S208), and this routine ends.
As shown in FIG. 3, the voltage correction can estimate the remaining capacity of the module battery from the voltage detected by the abnormal voltage detection system from the relationship between the voltage of the module battery and the remaining capacity. Is applied to the relationship between the voltage detected by the normal voltage detection system and the remaining capacity to estimate the voltage. Each module battery 24a to 24n
In the case of an abnormal voltage detection system that detects a higher voltage, the adjustment to make the voltage closer to the corrected voltage is performed by a transistor 36 for each module battery 24 whose voltage is detected by the normal voltage detection system. Is turned on, and the power is consumed by the resistor 34. However, unlike the equalization processing, the discharge is not performed until the corrected voltage is reached.
The discharge is terminated at a voltage higher than the corrected voltage. On the other hand, in the case of an abnormal voltage detection system that detects a lower voltage, the operation is performed by turning on the transistor 36 for the module battery 24 whose voltage is detected by the abnormal voltage detection system and consuming power by the resistor 34. . Also in this case, the discharge is not completed until the corrected voltage reaches the voltage detected by the normal voltage detection system, but the discharge ends at a slightly higher voltage.

According to the battery pack device 20 of the embodiment described above, it is possible to detect an abnormality in the voltage detection system of the module batteries 24a to 24n. As a result, overdischarge and overcharge of the module battery 24 based on the abnormality of the voltage detection system can be prevented. Further, according to the battery pack device 20 of the embodiment, when the abnormality of the voltage detection system is detected, the voltage of the module battery 24 related to the abnormality is corrected and the voltages of the other module batteries 24a to 24n approach the corrected voltage. With such adjustment, overdischarge and overcharge of the module battery 24 based on the abnormality of the voltage detection system can be further prevented, and it can contribute to subsequent use.

In the battery pack device 20 of the embodiment, when the time change rate DS of the remaining capacity is outside the allowable range set by the product of the average value A multiplied by the predetermined coefficient a and the product of the average value A multiplied by the predetermined coefficient b. It is determined that the voltage detection system relating to the time change rate DS of the remaining capacity is abnormal, but the time change rate DS of the remaining capacity is determined by subtracting the predetermined value c from the average value A and adding the predetermined value d. The voltage detection system relating to the time rate of change DS of the remaining capacity may be determined to be abnormal when the voltage is outside the set allowable range. Here, the predetermined value c and the predetermined value d are constants that determine the upper limit and the lower limit of the allowable variation from the average value A of the time rate of change DSa to DSn of the remaining capacity,
It is determined by the characteristics and specifications of the unit cells 22 and the module batteries 24a to 24n.

In the battery pack device 20 of the embodiment, when an abnormality of the voltage detection system is detected, the voltage of the module battery 24 related to the abnormality is corrected, and the voltages of the other module batteries 24 are adjusted. When the abnormality of the voltage detection system is detected, the equalization processing may not be simply performed, and the correction of the voltage of the module battery 24 related to the abnormality and the adjustment of the voltage of the other module batteries 24 may not be performed.

In the battery pack apparatus 20 of the embodiment, the abnormality detection processing routine and the equalization processing routine are executed by the electronic control unit 40 as separate routines. However, before the processing in step S202 of the equalization processing routine. The processing in steps S102 to S110 of the abnormality detection processing routine may be performed, and the abnormality of the voltage detection system may be detected in the equalization processing routine.

In the battery pack device 20 of the embodiment, the remaining capacities Sa to Sn of the module batteries 24a to 24n are obtained by calculation based on the voltages Va to Vn of the module batteries 24a to 24n. 24a ~
The remaining capacity Sa to Sn of 24n may be directly detected, or a value calculated using a state value other than the voltages Va to Vn may be used.

In the battery pack device 20 of the embodiment, a plurality of unit cells 22 are connected in series and the module cells 24a to 24n
However, the module cells 24a to 24n may be constituted by one unit cell 22. In this case, the cell equalizing circuits 28a to 28n become unnecessary.

The embodiments of the present invention have been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a configuration of an assembled battery device 20 including an assembled battery abnormality detection device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of an abnormality detection processing routine executed by an electronic control unit 40 of the battery pack device 20 according to the embodiment.

FIG. 3 is an explanatory diagram showing an example of the relationship between the remaining capacity of a module battery and a voltage by a normal voltage detection system and the relationship between the remaining capacity of a module battery and a voltage by an abnormal voltage detection system.

FIG. 4 is a flowchart illustrating an example of an equalization processing routine executed by the electronic control unit 40 of the battery pack device 20 according to the embodiment.

[Explanation of symbols]

10 load, 20 assembled battery device, 21 assembled battery, 22
Cell, 24a-24n module battery, 26a-2
6n voltage detection line, 28a to 28n cell equalizing circuit, 32a to 32n + 1 conductive line, 34a to 34n
Resistors, 36a-36n transistors, 38a-38
n signal line, 40 electronic control unit, 42 CP
U, 44 ROM, 46 RAM, 48 Indicator.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 AA01 BA03 CC04 EA02 EA05 EA06 EA08 GC05 5H030 AA06 AS20 BB01 BB21 FF43 FF44

Claims (7)

[Claims] 1. A module voltage detecting means for detecting a voltage of each of a plurality of module batteries of an assembled battery formed by connecting a plurality of module batteries constituted by at least one unit cell in series, and A battery pack abnormality detecting device, comprising: an equalizing unit that equalizes the voltage of each module battery based on the voltage of the module battery; and a remaining capacity detecting unit that detects a remaining capacity of each of the plurality of module batteries. And an abnormality determining unit that determines abnormality of the module voltage detecting unit based on the detected remaining capacity of each module battery. 2. The abnormality detecting device for a battery pack according to claim 1, wherein said abnormality determining means determines the abnormality based on a change rate of the remaining capacity of each module battery. 3. The abnormality determining means includes a change rate average value calculating means for calculating an average value of a change rate of the remaining capacity of each module battery, wherein the change rate of the remaining capacity of any one of the module batteries is equal to the change rate. 3. A means for determining that the voltage detection system of the module battery in the module battery detection means is abnormal when the average value of the change rate calculated by the average value calculation means is greater than or less than a predetermined value or more. Battery battery abnormality detection device. 4. The abnormality determining means includes a change rate average value calculating means for calculating an average value of a change rate of the remaining capacity of each module battery, wherein the change rate of the remaining capacity of any one of the module batteries is the change rate. 3. The set according to claim 2, wherein the means for determining that the voltage detection system of the module battery of the module battery detection means is abnormal when the average value of the change rate calculated by the average value calculation means is outside a predetermined range including the average value. Battery abnormality detection device. 5. An assembled battery device having an assembled battery in which a plurality of module batteries constituted by at least one unit cell are connected in series, wherein the abnormality detecting device for an assembled battery according to any one of claims 1 to 4. And an equalization restricting means for restricting equalization by the equalizing means when an abnormality is detected by the abnormality detecting device. 6. The set according to claim 5, further comprising, when an abnormality is detected by the abnormality detection device, an abnormal-time voltage correction unit that corrects a voltage of the battery module based on a remaining capacity of the battery module related to the abnormality. Battery device. 7. A remaining capacity adjusting means for adjusting the remaining capacity of another battery module in a direction approaching the remaining capacity of the battery module when the abnormality is detected by the abnormality detecting device. 7. The battery pack device according to 6.