JP3975798B2 - Abnormality detection apparatus and abnormality detection method for battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery abnormality detection device, and more particularly to an abnormality detection device that detects an abnormality in an assembled battery configured by connecting a plurality of single cells in series.
[0002]
[Prior art]
As a battery that is mounted on a vehicle and supplies power to a drive source or supplies power to an auxiliary machine, there is an assembled battery configured by connecting a plurality of single cells in series. The unit cells constituting such an assembled battery deteriorate with the progress of use of each unit cell. This deterioration occurs due to corrosion of the active material inside the battery. Phenomena such as an increase in internal resistance appear.
[0003]
In addition, the voltage of individual cells varies due to variations in self-discharge current of the cells, variations in current consumption of the cell voltage detection circuit attached to the cells, and the like. In addition to this, the voltage of individual cells varies due to variations in charging efficiency. There has been proposed an equalizing device that eliminates the voltage imbalance of an assembled battery including such single cells. In this equalization apparatus, the voltage imbalance of each unit cell is eliminated by detecting the voltage for each unit cell and discharging the other unit cell so that the voltage is almost the same as the minimum unit cell.
[0004]
Furthermore, regarding such an assembled battery equalizing apparatus, Japanese Patent Laid-Open No. 2002-10512 discloses a method for adjusting the capacity of the assembled battery.
[0005]
The capacity adjustment method disclosed in this publication corresponds to the setting step of setting the minimum voltage value of the open voltage of the cells constituting the assembled battery as the capacity adjustment target value, and the deviation from the target value for each cell. The calculation step for calculating the discharge time, the discharge step for discharging only for the calculated discharge time, and the voltage drop amount is relatively larger than that of many other single cells. If the cells that are approaching the same level as the voltage of many cells are not abnormal, the open voltage decreases as the threshold value is exceeded because the average of the cell voltages excluding the maximum and minimum voltage values is obtained. A determination step of determining that the unit cell is abnormal.
[0006]
In this capacity adjustment method, the discharge time is calculated for each unit cell, and based on the open circuit voltage after discharge, the unit cell having a normal voltage drop amount and the unit cell having an abnormal voltage drop amount are clearly identified. , It is possible to detect a unit cell in which an abnormality has occurred.
[0007]
[Problems to be solved by the invention]
However, in the abnormality detection device disclosed in the above-mentioned publication, the discharge time must be calculated for each unit cell, and the configuration of the abnormality detection device becomes complicated.
[0008]
The present invention has been made in order to solve the above-described problems, and provides an assembled battery abnormality detection device and abnormality detection method that can easily and accurately detect abnormality of a single battery constituting the assembled battery. Is to provide.
[0009]
[Means for Solving the Problems]
The abnormality detection device according to the first aspect of the invention detects an abnormality of an assembled battery configured by connecting a plurality of single cells in series. This abnormality detection device was measured when each cell was uniformly discharged from the capacity equalization means for equalizing the capacity of the plurality of cells and the state where the capacity of each cell was equalized. And an abnormality determining means for determining an abnormality of the unit cells constituting the assembled battery based on the voltage of each unit cell.
[0010]
According to the first invention, discharge is performed with the discharge amount in each unit cell made uniform from the state in which the capacity of each unit cell is equalized by the capacity equalizing means. At this time, for example, a resistor (corresponding to the same resistance value) provided in association with each unit cell included in the capacity equalizing means is discharged for the same discharge time. When the same discharge amount is discharged in this way, the decrease in the open voltage in the single cell that has deteriorated and the full charge capacity has decreased is larger than the decrease in the open voltage in the single cell in the initial state. For this reason, a single battery whose full charge capacity is reduced and the open circuit voltage is greatly reduced is a deteriorated battery and can be determined to be abnormal. For example, when the assembled battery is connected to a large-capacity load and discharged with a large current, the voltage drop in the unit cell that has deteriorated and has increased internal resistance is larger than the voltage drop in the unit cell in the initial state. For this reason, it is possible to determine that a battery cell whose internal resistance has increased and the open-circuit voltage has greatly decreased is a deteriorated battery and is abnormal. As a result, it is possible to provide an assembled battery abnormality detection device that can easily and accurately detect abnormality of the cells constituting the assembled battery.
[0011]
In the battery pack abnormality detection device according to the second invention, in addition to the configuration of the first invention, the abnormality determination means uses the capacity equalization means from the state where the capacity of each unit cell is equalized. Means for determining an abnormality of the unit cells constituting the assembled battery based on the voltage of each unit cell measured when the unit cell is discharged by the same amount is included.
[0012]
According to the second aspect of the invention, the discharge amount in each unit cell is made uniform from the state in which the capacity of each unit cell is equalized by the capacity equalizing means. At this time, a resistor (corresponding to the same resistance value) provided in association with each unit cell included in the capacity equalizing means is discharged for the same discharge time. When the same discharge amount is discharged in this way, the decrease in the open voltage in the single cell that has deteriorated and the full charge capacity has decreased is larger than the decrease in the open voltage in the single cell in the initial state. For this reason, a single battery whose full charge capacity is reduced and the open circuit voltage is greatly reduced is a deteriorated battery and can be determined to be abnormal. As a result, it is possible to provide an assembled battery abnormality detection device that can easily and accurately detect abnormality of the cells constituting the assembled battery.
[0013]
In addition to the configuration of the first invention, the abnormality determination device for the assembled battery according to the third invention is configured so that the abnormality determining means sets the assembled battery to a large-capacity load from a state in which the capacity of each unit cell is equalized. Means for determining an abnormality of the unit cells constituting the assembled battery based on the voltage of each unit cell measured when discharged by connecting.
[0014]
According to the third aspect of the invention, from the state where the capacity of each unit cell is equalized by the capacity equalizing means, the discharge amount in each unit cell is made uniform and discharged. At this time, when the assembled battery is connected to a large-capacity load and discharged at a large current, the voltage drop in the unit cell that has deteriorated and has increased internal resistance is larger than the voltage drop in the unit cell in the initial state. For this reason, a unit cell whose open-circuit voltage is greatly decreased due to an increase in the internal resistance of the unit cell can be determined to be abnormal because it is a deteriorated battery. As a result, it is possible to provide an assembled battery abnormality detection device that can easily and accurately detect abnormality of the cells constituting the assembled battery.
[0015]
In the battery pack abnormality detection device according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the unit cell is a lithium battery.
[0016]
According to the fourth invention, it is possible to provide an abnormality detection device capable of accurately detecting an abnormality of an assembled battery including a plurality of lithium batteries.
[0017]
An abnormality detection method according to a fifth aspect of the invention detects an abnormality of an assembled battery configured by connecting a plurality of single cells in series. This abnormality detection method includes a capacity equalization step for equalizing the capacities of a plurality of unit cells, and each unit measured when each unit cell is uniformly discharged from a state in which the capacity of each unit cell is equalized. And an abnormality determination step of determining an abnormality of the single cells constituting the assembled battery based on the voltage of the battery.
[0018]
According to the fifth aspect of the invention, from the state where the capacity of each unit cell is equalized in the capacity equalizing step, the discharge amount in each unit cell is made uniform and discharged. At this time, for example, a resistor (corresponding to the same resistance value) provided in association with each unit cell used in the capacity equalization step is discharged for the same discharge time. When the same discharge amount is discharged in this way, the decrease in the open voltage in the single cell that has deteriorated and the full charge capacity has decreased is larger than the decrease in the open voltage in the single cell in the initial state. For this reason, a single battery whose full charge capacity is reduced and the open-circuit voltage is greatly reduced is a deteriorated battery and can be determined to be abnormal. For example, when the assembled battery is connected to a large-capacity load and discharged with a large current, the voltage drop in the unit cell that has deteriorated and has increased internal resistance is larger than the voltage drop in the unit cell in the initial state. For this reason, a unit cell whose open-circuit voltage is greatly decreased due to an increase in the internal resistance of the unit cell can be determined to be abnormal because it is a deteriorated battery. As a result, it is possible to provide an assembled battery abnormality detection method capable of easily and accurately detecting abnormality of the single cells constituting the assembled battery.
[0019]
In the abnormality detection method according to the sixth aspect of the invention, in addition to the configuration of the fifth aspect of the invention, the abnormality determination step uses the capacity equalization step to replace each unit cell from the state where the capacity of each unit cell is equalized. The method includes a step of determining an abnormality of the unit cells constituting the assembled battery based on the voltage of each unit cell measured when the same amount is discharged.
[0020]
According to the sixth invention, discharge is performed with the discharge amount in each unit cell made uniform from the state in which the capacity of each unit cell is equalized in the capacity equalization step. At this time, a resistor (corresponding to the same resistance value) provided in association with each unit cell used in the capacity equalization step is discharged for the same discharge time. When the same discharge amount is discharged in this way, the decrease in the open voltage in the single cell that has deteriorated and the full charge capacity has decreased is larger than the decrease in the open voltage in the single cell in the initial state. For this reason, a single battery whose full charge capacity is reduced and the open circuit voltage is greatly reduced is a deteriorated battery and can be determined to be abnormal. As a result, it is possible to provide an assembled battery abnormality detection method capable of easily and accurately detecting abnormality of the single cells constituting the assembled battery.
[0021]
In the abnormality detection method according to the seventh invention, in addition to the configuration of the fifth invention, the abnormality determination step connects the assembled battery to a large-capacity load from a state in which the capacity of each unit cell is equalized. The step of determining the abnormality of the unit cells constituting the assembled battery based on the voltage of each unit cell measured when discharged by the above.
[0022]
According to the seventh invention, discharge is performed with the discharge amount in each unit cell made uniform from the state in which the capacity of each unit cell is equalized in the capacity equalization step. At this time, when the assembled battery is connected to a large-capacity load and discharged at a large current, the voltage drop in the unit cell that has deteriorated and has increased internal resistance is larger than the voltage drop in the unit cell in the initial state. For this reason, a unit cell whose open-circuit voltage is greatly decreased due to an increase in the internal resistance of the unit cell can be determined to be abnormal because it is a deteriorated battery. As a result, it is possible to provide an assembled battery abnormality detection method capable of easily and accurately detecting abnormality of the single cells constituting the assembled battery.
[0023]
In the abnormality detection method according to the eighth invention, in addition to the configuration of any one of the fifth to seventh inventions, the unit cell is a lithium battery.
[0024]
According to the eighth invention, it is possible to provide an abnormality detection method capable of accurately detecting an abnormality of an assembled battery composed of a plurality of lithium batteries.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. In the following description, it is assumed that the assembled battery is constituted by a lithium battery, but the present invention is not limited to this. In addition, this assembled battery will be described as being mounted on a vehicle.
[0026]
<First Embodiment>
FIG. 1 shows an assembled battery abnormality detection system according to the present embodiment. This abnormality detection system includes a relay 200, an assembled battery 300, and an abnormality detection device 100 that detects an abnormality of the assembled battery 300 connected to the load 400 via the relay 200. N (N is a natural number) unit cells are connected in series. The abnormality detection apparatus 100 includes a battery ECU (Electronic Control Unit) connected to connection points of the cells B (1) to B (N) constituting the assembled battery 300 via conductive lines L (0) to L (N). ) 110, and transistors T (1) to T (N) and resistors R (1) to R (N) connected in series between the conductive lines L (0) to L (N), respectively. The resistance values of the resistors R (1) to R (N) are all the same.
[0027]
The assembled battery 300 is configured by connecting single cells B (1) to B (N), which are lithium batteries, in series. A load 400 is connected to the assembled battery 300 via the relay 200.
[0028]
Battery ECU 110 includes a CPU 112, a ROM (Read Only Memory) 114 that stores a program executed by CPU 112, and a RAM (Random Access Memory) 116 that temporarily stores data. The battery ECU 100 outputs a lighting signal to the indicator 120 that displays an abnormality of the assembled battery 300, an on / off signal to each of the transistors T (1) to T (N), and the like via an output port.
[0029]
When the transistors T (1) to T (N) are turned on by the on / off signal from the battery ECU 100, current flows through the resistors connected in series via the turned-on transistors, and power is consumed.
[0030]
The CPU 112 of the battery ECU 110 detects the voltages VB (1) to VB (N) of the individual cells B (1) to B (N). The CPU 112 detects the voltages VB (1) to VB (N) of the single cells B (1) to B (N) as potential differences between the conductive lines L (0) to L (N).
[0031]
The CPU 112 of the battery ECU 110 incorporates a timer capable of measuring that a set charging time has elapsed from a predetermined timing. The CPU 112 detects the completion of the test discharge time after the equalization process using this timer. Since the resistance values of the resistors R (1) to R (N) are all the same, the discharge amount and the discharge time have a correlation. In the following description, the discharge amount is not directly detected, and after the equalization process, the resistors R (1) to R (N) of the equalization circuit are used to discharge only the discharge time common to each unit cell. Although described as detecting an abnormal unit cell based on the voltage of each unit cell after the discharge time has elapsed, the present invention is not limited to this. For example, a physical quantity other than the discharge time is detected, the discharge quantity is calculated based on the physical quantity, and abnormal cells are detected based on the voltage after discharging so that the discharge quantity is uniform in each single battery. You may do.
[0032]
With reference to FIG. 2, the relationship between SOC (States Of Charge) and OCV (Open Current Voltage) of a lithium battery which is a target for detecting an abnormality in the abnormality detection system for an assembled battery according to the present embodiment will be described. As shown in FIG. 2, when SOC is plotted on the horizontal axis and OCV is plotted on the vertical axis, the lithium battery tends to increase in OCV as the SOC increases. When the measured OCV is 4.1 volts, the SOC is 100%.
[0033]
The relationship between the capacity of the lithium battery and the OCV will be described with reference to FIG. FIG. 3 shows the relationship between capacity and OCV for a lithium battery in an initial state and a lithium battery in a deteriorated state. The lithium battery in the initial state and not deteriorated is fully charged when the measured OCV is 4.1 volts and is charged with an electric quantity of about 12 Ah. On the other hand, in a lithium battery in which the full charge capacity is deteriorated due to deterioration over time, the charged electric capacity is about 8 Ah even if the measured OCV is 4.1 volts. That is, even when the OCV of the lithium battery is measured to be the same 4.1 volts, the lithium battery in the initial state is charged with a capacity of 12 Ah, and the deteriorated lithium battery is charged with a capacity of 8 Ah.
[0034]
As shown in FIG. 3, both the capacity and the OCV are increased by charging the lithium battery, and both the capacity and the OCV are decreased by discharging from the lithium battery. Further, as shown in FIG. 3, when the same discharge amount ΔQ is discharged from the fully charged state to the lithium battery in the initial state and the lithium battery in the deteriorated state, the deterioration state is higher than the OCV of the lithium battery in the initial state. The lithium ion battery has a lower OCV.
[0035]
With reference to FIG. 4, a control structure of a program executed by battery ECU 110 of abnormality detection apparatus 100 for the assembled battery according to the present embodiment will be described.
[0036]
In step (hereinafter step is abbreviated as S) 100, CPU 112 of battery ECU 110 detects voltage VB (K) (K = 1 to N) of each unit cell. In S102, CPU 112 determines whether or not variation in voltage VB is smaller than ΔV. If variation in voltage VB is smaller than ΔV (YES in S102), the process proceeds to S106. If not (NO in S102), the process proceeds to S104.
[0037]
In S104, CPU 112 performs equalization processing using an equalization circuit. At this time, the transistor T (K) is turned on and the cells are discharged until the voltage of each cell becomes the lowest voltage among the voltages VB (K) of the cells.
[0038]
In S106, CPU 112 determines whether or not the test discharge condition is satisfied. This determination is made after the equalization process is completed, and is determined based on whether or not the load 400 and the assembled battery 300 are disconnected. If the test discharge condition is satisfied (YES in S106), the process proceeds to S108. If not (NO in S106), the process returns to S106 and waits until the test discharge condition is satisfied.
[0039]
In S108, CPU 112 turns on transistor T (K) (K = 1 to N). In S110, CPU 112 starts a timer. In S112, CPU 112 determines whether or not a predetermined time has elapsed since the timer start. If a predetermined time has elapsed from the start of the timer (YES in S112), the process proceeds to S114. If not (NO in S112), the process returns to S112 and waits until a predetermined time elapses from the start of the timer.
[0040]
In S114, CPU 112 turns off transistor T (K) (K = 1 to N). In S116, CPU 112 initializes variable K (K = 1). At S118, CPU 112 detects voltage VB (K) of the Kth unit cell. In S120, CPU 112 determines whether or not voltage VB (K) of the Kth cell is lower than a predetermined threshold value VBLIM related to the voltage. If voltage VB (K) of Kth unit cell is lower than threshold value VBLIM (YES in S120), the process proceeds to S122. If not (NO in S120), the process proceeds to S124.
[0041]
In S122, CPU 112 sets an abnormality flag for the Kth unit cell. In S124, CPU 112 adds 1 to variable K. In S126, CPU 112 determines whether variable K is larger than the number N of single cells. If variable K is larger than the number N of single cells (YES in S126), the process proceeds to S128. If not (NO in S126), the process returns to S118, and the process for the next unit cell is performed.
[0042]
At S128, CPU 112 stores the unit cell in which the abnormality flag is set as abnormal in RAM 116. Thereafter, the CPU 112 causes the indicator 120 to display information regarding the abnormality of the single battery.
[0043]
The operation of CPU 112 of battery ECU according to the present embodiment based on the above-described structure and flowchart will be described.
[0044]
When the vehicle stops and the ignition switch is turned off, the voltage VB (K) (K = 1 to N) of each unit cell is detected (S100). If variation in voltage VB is smaller than ΔV (YES in S102), equalization processing is not performed and it is determined whether or not test discharge conditions are satisfied (S106).
[0045]
If the test discharge condition is satisfied (YES in S106), transistor T (K) (K = 1 to N) is turned on (S108). When the timer is started (S110) and a predetermined time has elapsed (YES in S112), transistor T (K) (K = 1 to N) is turned off (S114). The voltage VB (K) of the Kth unit cell is detected (S118). If detected voltage VB (K) is lower than a predetermined threshold value VBLIM (YES in S120), an abnormality flag for the Kth cell is set (S122).
[0046]
At this time, as described with reference to FIG. 3, even when the same discharge amount is discharged in the single battery, the lithium battery deteriorated compared with the lithium battery in the initial state has a lower OCV. Therefore, when the voltage VB (K) of the Kth unit cell is lower than the predetermined threshold value VBLIM, the abnormality flag is set as that unit cell has deteriorated. Such a process is repeated for the number N of unit cells. When processing for all the unit cells is performed, the unit cell in which the abnormality flag is set is stored as an abnormality in the RAM 116 (S128).
[0047]
As described above, according to the abnormality detection device according to the present embodiment, after eliminating the variation in the capacity of the unit cells by the equalization circuit, the resistance provided corresponding to each unit cell of the equalization circuit is provided. Use and discharge for the same amount of time. At this time, since the resistance of the equalization circuit has the same resistance value, the same amount of electricity ΔQ is discharged when discharged for the same discharge time. When the same amount of electricity ΔQ is discharged in a plurality of single cells, a battery whose OCV has decreased more can be determined as a battery whose full charge capacity has decreased.
[0048]
In the present embodiment, it is determined that the battery has a reduced full charge capacity when the voltage VB (K) of the battery after the test discharge is lower than a predetermined threshold value VBLIM. Is not limited to this. In the present invention, when the voltage VB (K) of the unit cell after the test discharge is relatively lower than the other cells constituting the assembled battery, all the determinations that determine that the unit cell has a reduced full charge capacity Including methods.
[0049]
<Second Embodiment>
An assembled battery abnormality detection system according to a second embodiment of the present invention will be described below. As shown in FIG. 5, the abnormality detection system according to the present embodiment includes an abnormality detection device 100 according to the first embodiment. The abnormality detection apparatus 100 is connected to a 36-volt battery 302 that is the assembled battery 300 according to the first embodiment. The 36-volt battery 302 includes internal resistances RB (1) to RB (N) in the respective cells B (1) to B (N). Relay 200 is connected to DC / DC converter 500, and DC / DC converter 500 is connected to 12-volt battery 600.
[0050]
When relay 200 is turned on, a large current flows from 36-volt battery 302 to 12-volt battery 600 via DC / DC converter 500. Since the hardware configuration other than this is the same as the hardware configuration in the abnormality detection system according to the first embodiment described above, detailed description thereof will not be repeated here.
[0051]
With reference to FIG. 6, a control structure of a program executed by battery ECU 110 of abnormality detection device 100 according to the present embodiment will be described. In the flowchart shown in FIG. 6, the same steps as those in the flowchart shown in FIG. 4 are given the same step numbers. The processing for them is the same. Therefore, detailed description thereof will not be repeated here.
[0052]
In S200, CPU 112 turns on relay 200, supplies power to DC / DC converter 500, and starts test discharge. In S202, CPU 112 initializes variable K (K = 1). In S204, CPU 112 detects voltage VB (K) of the Kth battery. In S206, CPU 112 stores voltage VB (K) in RAM 116. In S208, CPU 112 adds 1 to variable K. In S210, CPU 112 determines whether or not variable K is larger than the number N of single cells. If variable K is larger than the number N of single cells (YES in S210), the process proceeds to S212. If not (NO in S210), the process returns to S204, and the process for the next unit cell is performed.
[0053]
In S212, CPU 112 turns off relay 200 and ends the test discharge. In S214, CPU 112 determines the lowest voltage VBMIN among the N unit cells. The unit cell determined to have the lowest voltage is the unit cell that has the smallest voltage drop due to the increase in the internal resistance of the cell and is the least deteriorated among the assembled cells.
[0054]
In S216, CPU 112 initializes variable K (K = 1). In S218, CPU 112 calculates evaluation value E as E = voltage VB (K) / VBMIN. At S220, CPU 112 determines whether or not evaluation value E is greater than a predetermined threshold value EMAX. If evaluation value E is larger than predetermined threshold value EMAX (YES in S220), the process proceeds to S222. If not (NO in S220), the process proceeds to S224. At this time, if the internal resistance RB (2) associated with the battery B (2) is greater than the internal resistance RB (1) associated with the first battery B (1), the second battery B ( In 2), a larger voltage drop due to the internal resistance of the battery occurs. Therefore, the voltage VB (K) is detected high. As a result, the evaluation value E of the second battery B (2) is calculated to be larger than the evaluation value E of the first battery B (1).
[0055]
In S222, CPU 112 sets an abnormality flag for the Kth unit cell. In S224, CPU 112 adds 1 to variable K. In S226, CPU 112 determines whether or not variable K is larger than the number N of single cells. If variable K is larger than the number N of single cells (YES in S226), the process proceeds to S128. If not (NO in S226), the process returns to S218, and the process for the next unit cell is performed.
[0056]
An operation of CPU 112 of abnormality detection apparatus 100 according to the present embodiment based on the above-described structure and flowchart will be described.
[0057]
When conditions such as the vehicle stops and the ignition switch is turned off, the voltage VB (K) (K = 1 to N) of each unit cell is detected (S100). If variation in voltage VB is smaller than ΔV (YES in S102), equalization processing is not performed, relay 200 is turned on, power is supplied from 36-volt battery to DC / DC converter 500, and test discharge starts. (S200). In this state, the voltage VB (K) of the Kth cell is detected (S204), and the detected voltage VB (K) is stored in the RAM 116 (S206). Such a process is repeated for all the single cells.
[0058]
Thereafter, the relay 200 is turned off and the test discharge ends (S212). The lowest voltage VBMIN among the N cells is determined (S214). The evaluation value E is calculated by dividing the voltage VB (K) stored in the RAM 116 for each single cell by VBMIN (S218). If calculated evaluation value E is greater than a predetermined threshold value EMAX (YES in S220), an abnormality flag for the Kth unit cell is set (S222). Such a process is repeatedly executed for all the single cells.
[0059]
As described above, according to the battery pack abnormality detection device according to the present embodiment, each unit when a large current of, for example, about 100 amperes is passed using a DC / DC converter or the like connected to the battery pack. Measure the battery voltage. In the unit cell in which the internal resistance of the unit cell has increased due to changes over time, the voltage VB (K) that appears as a voltage drop is greatly measured. A battery having a large voltage drop due to internal resistance is set with an abnormality flag indicating that it is a deteriorated battery, and an abnormality of a single battery constituting the assembled battery can be detected.
[0060]
In the present embodiment, the evaluation value E, which is the ratio of the voltage VB (K) to the lowest voltage VBMIN unit cell when a large current is flowing, is greater than a predetermined threshold value EMAX. In addition, although it is determined that the cell has an increased internal resistance, the present invention is not limited to this. In the present invention, all the determinations that determine that the internal resistance is increased when the voltage VB (K) of the unit cell during the test discharge is relatively higher than the other cells constituting the battery assembly. Including methods.
[0061]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a control block diagram of an abnormality detection system according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between SOC and OCV.
FIG. 3 is a diagram illustrating a relationship between capacity and OCV.
FIG. 4 is a flowchart showing a control structure of a program executed by the battery ECU of the abnormality detection system according to the first embodiment of the present invention.
FIG. 5 is a control block diagram of an abnormality detection system according to a second embodiment of the present invention.
FIG. 6 is a flowchart showing a control structure of a program executed by the battery ECU of the abnormality detection system according to the second embodiment of the present invention.
[Explanation of symbols]
100 abnormality detection device, 110 battery ECU, 112 CPU, 114 ROM, 116 RAM, 200 relay, 300 assembled battery, 302 36V battery, 400 load, 500 DC / DC converter, 600 12V battery.

Claims (8)

An abnormality detection device that detects an abnormality of a battery pack configured by connecting a plurality of single cells in series,
Capacity equalizing means for equalizing the capacity of the plurality of single cells;
Based on the voltage of each unit cell measured when each unit cell is uniformly discharged from the state in which the capacity of each unit cell is equalized, an abnormality of the unit cell constituting the assembled battery is determined. And an abnormality detection device for the assembled battery. The abnormality determination means is based on the voltage of each unit cell measured when the unit cells are discharged by the same amount from the state where the capacity of each unit cell is equalized. The abnormality detection device for an assembled battery according to claim 1, further comprising means for determining an abnormality of the single cells constituting the assembled battery. The abnormality determining means is based on the voltage of each unit cell measured when discharging the battery by connecting the assembled battery to a large-capacity load from a state where the capacity of each unit cell is equalized. The assembled battery abnormality detection device according to claim 1, comprising means for determining an abnormality of a single battery constituting the assembled battery. The assembled battery abnormality detection device according to claim 1, wherein the unit cell is a lithium battery. An abnormality detection method for detecting an abnormality in an assembled battery configured by connecting a plurality of single cells in series,
Capacity equalization step for equalizing the capacity of the plurality of unit cells;
Based on the voltage of each unit cell measured when each unit cell is uniformly discharged from the state in which the capacity of each unit cell is equalized, an abnormality of the unit cell constituting the assembled battery is determined. An abnormality detection method for an assembled battery, including an abnormality determination step. The abnormality determination step is based on the voltage of each unit cell measured when the unit cell is discharged by the same amount from the state in which the unit cell capacity is equalized using the capacity equalization step. The abnormality detection method for an assembled battery according to claim 5, further comprising a step of determining an abnormality of a single battery constituting the assembled battery. The abnormality determination step is based on the voltage of each unit cell measured when discharging the battery by connecting the assembled battery to a large-capacity load from a state where the capacity of each unit cell is equalized. The assembled battery abnormality detection method according to claim 5, comprising a step of determining an abnormality of a single battery constituting the assembled battery. The battery cell abnormality detection method according to claim 5, wherein the single battery is a lithium battery.

Images