JP3709785B2 - Diagnostic device for battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery diagnostic apparatus.
[0002]
[Prior art]
First, the configuration of the assembled battery will be described with reference to FIG. In the assembled battery A, m × n unit cells Cij (i = 1 to m, j = 1 to n) are connected in series. The unit cells Cij are grouped in units of n to form a battery pack Mi (i = 1 to m). The cell controller CCi (i = 1 to m) performs cell voltage measurement and capacity adjustment for each battery pack. For example, the cell controller CC1 controls charging / discharging of n unit cells C11 to C1n included in the battery pack M1. One cell controller CCi and a battery pack Mi controlled by the cell controller are collectively referred to as a module. The battery controller BC controls each cell controller CCi to control charging / discharging of the entire assembled battery.
[0003]
Next, a detailed circuit diagram of the cell controller CCi will be described with reference to FIG. In FIG. 5, Cij is a single cell, Rij (i = 1 to m, j = 1 to n) is a resistor, Tij (i = 1 to m, j = 1 to n) is a transistor, and a portion surrounded by a one-dot chain line CCi is a cell controller that controls each unit cell in the module, BC is a battery controller that controls the entire assembled battery, 1 is a control unit that performs calculations according to various input signals and outputs control signals, and 2 is a module The cell voltage measurement line connected to each cell in the cell, 3 is a signal line to each transistor in the module, 4 is a communication line between the battery controller and each cell controller, and the portion 5 surrounded by a one-dot chain line is capacity adjustment A circuit 6 is a diagnostic voltage measurement line for detecting a current flowing through the capacitance adjusting circuit 5.
[0004]
The assembled battery maximizes its capacity by adjusting the capacity of each unit cell. Therefore, a capacity adjustment circuit 5 that adjusts the charging rate of each unit cell to be uniform is provided. In order to adjust the capacity, the open voltage of each single cell is measured by the cell voltage measuring line 2, and the control unit 1 determines the discharge amount of each single cell Cij based on the measured open voltage of the single cell. To do. The control unit 1 determines the closing time of the transistor Tij according to the discharge amount, and discharges the charge of the unit cell Cij via the resistor Rij.
[0005]
For example, when the transistor T11 is closed, the cell C11 is discharged through the resistor R11. The same applies to other unit cells. The resistance values of the resistors Rij are the same, and the adjustment capacitance is controlled by the time for closing the transistor Tij.
[0006]
If the capacity adjustment circuit 5 breaks down, the capacity of the assembled battery A cannot be fully exhibited, so the capacity adjustment circuit 5 is diagnosed by the diagnostic voltage measurement line 6.
[0007]
In the fault diagnosis of the capacity adjustment circuit 5, the adjustment circuit section is diagnosed by measuring the voltage of the diagnostic voltage measurement line 6 by simultaneously turning on or off all the capacity adjustment circuits when the assembled battery A is not loaded.
[0008]
First, a signal for turning off the transistor Tij is sent from the signal line 3, and it is determined that the detection voltage of the diagnostic voltage measurement line 6 is the same as the high potential side of the unit cell, so that the transistor Tij is turned off. Confirm. Thereafter, a signal to turn on the transistor Tij is sent, and it is confirmed that the transistor Tij is turned on by determining that the detection voltage of the diagnostic voltage measurement line 6 is substantially the same as the low potential side of the unit cell. do it.
[0009]
[Problems to be solved by the invention]
The problem of the above diagnostic method will be described with reference to FIG. In the diagnosis of the conventional capacity adjustment circuit 5, since the unit cell voltages of all the unit cells are approximately the same value, when all the transistors Tij are turned on, the cell voltage shared between the adjacent unit cells is Although currents like Id11 and Id12 tend to flow through the measurement line 7, since Id11 and Id12 have approximately the same size in opposite directions, they cancel each other. As a result, the cell voltage measurement line is configured such that the capacity adjustment current Id flows only to the capacity adjustment circuit 5 of all the single cells as shown in FIG. For this reason, although the fault diagnosis for the capacity adjustment circuit 5 has been made, the cell voltage measurement line 2 of the unit cell and the unit cell and the connection part 7 shared between the adjacent batteries of the capacity adjustment circuit 5 are defective. When the impedance component r is present, there is a problem that the abnormality cannot be detected.
[0010]
Therefore, the present invention is also effective when the impedance component r exists due to a defect in the connection portion 7 shared between the cells, the cell voltage measuring line 2 and the adjacent battery of the capacity adjustment circuit 5. It is an object of the present invention to provide an assembled battery diagnostic device that can detect a battery pack.
[0011]
[Means for Solving the Problems]
In the invention of claim 1, a plurality of unit cells are connected in series, a cell voltage measuring line connected in a shared state between the poles of each unit cell and between adjacent unit cells, a resistor and a switch in series Connect the discharge circuit consisting of the connected cells to each unit cell in parallel, and turn on the switch to adjust the unit cell capacity and measure the voltage of each unit cell using the cell voltage measurement line On the other hand, a control unit that controls on / off of the switch is provided, and the capacity adjustment circuit for the assembled battery is provided for each predetermined number so that the capacity adjustment circuit for at least one adjacent assembled battery is not simultaneously driven in the control unit. A switch driving unit that drives the switch of the capacity adjustment circuit that has not been driven thereafter, and a memory that measures and stores the voltage of each unit cell when driving the switch of the capacity adjustment circuit Department and The open voltage (V0ij) of each single cell measured at no load is stored, and the voltage of each single cell and the open voltage of each single cell measured at the time of driving the switch of the capacity adjustment circuit stored in the storage unit (V0ij) is compared with the voltage comparison part which judges whether it is abnormal.
[0012]
According to a second aspect of the present invention, in the assembled battery diagnostic device according to the first aspect, the predetermined number for driving the switch of the capacity adjustment circuit is one.
[0013]
According to a third aspect of the present invention, in the assembled battery diagnostic apparatus according to the first aspect, the control unit stores the circuit portion determined to be abnormal, and when a plurality of abnormal circuit portions are recognized, If it is determined whether the abnormalities are adjacent to each other, and the locations of the abnormal circuit portions are determined to be adjacent to each other, it is determined that there is a failure in the shared portion of the cell voltage measurement line between them, and the locations of the abnormal circuit portions are In the case where they are not adjacent to each other, there is a feature of having a determination unit that determines that there is a possibility of misdiagnosis.
[0014]
【The invention's effect】
According to the first aspect of the present invention, it is possible to detect failure diagnosis, for example, generation of an impedance component due to connection failure of each cell, a cell voltage measurement line, and a capacity adjustment circuit.
[0015]
According to the invention of claim 2, in addition to the effect of the invention of claim 1, the failure location can be specified by two diagnosis of the odd-numbered stage and the even-numbered stage of the unit cell, so that the time taken for the fault diagnosis is suppressed. Is possible.
[0016]
According to the invention of claim 3, in addition to the effect of the invention of claim 1, by comparing the diagnosis results of adjacent single cells, it can be confirmed whether or not each diagnosis result is misdiagnosed. At the same time, it is possible to identify the defective part.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Although the embodiment will be described with reference to FIG. 1, the difference between the present embodiment and the conventional example shown in FIG. 5 is only the difference between the control unit 100 and the control unit 1. The flow will be described with reference to FIG. 2, and the other components are denoted by the same reference numerals as those in FIG.
[0018]
Here, an example in which the capacitance adjusting circuit 5 is driven every other time will be described.
[0019]
When power is supplied to the battery controller BC, the diagnosis of the capacity adjustment circuit 5 in step 110 is started, and the switch SW1 in FIG. In addition, the NG flag set to 1 is initialized to 0 when there is a circuit abnormality. In step 120, the transistors Tij of the capacity adjustment circuit 5 for all single cells are turned off. Next, at step 130, if the potential difference between the high potential side of the cell voltage measurement line 2 and the diagnostic voltage measurement line 6, that is, the voltage drop of the resistor Rij is within a predetermined range, it is confirmed that the transistor Tij of the capacitance adjustment circuit 5 is off. I can do it. Here, if there is a portion that does not fall within the predetermined range, there is a leakage current in the capacity adjustment circuit 5 (step 290).
[0020]
Next, at step 140, the open circuit voltage V0ij (i = 1 to m, j = 1 to n) of each unit cell is detected. The open voltage V0ij of each unit cell Cij is measured by the cell controller CCi and stored in the voltage comparison unit of the control unit 100.
[0021]
In step 150, the switch drive unit of the control unit 100 turns on the transistor Tij of the capacity adjustment circuit 5 in the odd-numbered stages (j = 1, 3, 5,...). In step 160, the fact that the capacity adjustment circuit 5 in the odd-numbered stage is turned on indicates that the difference between the voltage of the diagnostic voltage measurement line 6 and the voltage on the low potential side of the cell voltage measurement line 2, that is, the voltage between the emitter and collector of Tij is predetermined. Confirm by being within range. If there is a transistor that does not turn on, it is an abnormality of the capacity adjustment circuit system (step 290).
[0022]
Next, in step 170, the storage unit of the control unit 100 detects and stores the voltage between terminals of the capacity adjustment circuit having the transistors Tij of the odd-numbered capacity adjustment circuit 5, that is, the voltage Viodd between the terminals of the unit cell.
[0023]
In step 180, the voltage comparison unit turns on the open circuit voltage of the odd-numbered cells in the open circuit voltage V0ij stored in step 140 and the transistor Tij of the capacity adjustment circuit 5 stored in step 170. The voltage Viodd between the terminals of the unit cells is compared. Since the difference from the open circuit voltage V0ij increases when there is a slight impedance effect due to the failure of the connection part 7 to the cell voltage measuring line 2 and the capacity adjustment circuit 5 of each unit cell, it becomes possible to recognize an abnormality. . This will be described with reference to FIG.
[0024]
In FIG. 3, capacity adjustment currents Id11 and Id13 are currents flowing through the capacity adjustment circuits corresponding to the cells C11 and C13, and are generated when the transistors Tij of the odd-numbered capacity adjustment circuits are turned on. If there is an impedance abnormality r, the voltage of C13 measured by the cell voltage measurement line 2 will drop by r × Id13. Since this voltage drop amount causes the difference from the open circuit voltage V013 to exceed the predetermined drop amount Vr, it is detected as an abnormality.
[0025]
If an abnormality is detected in this way, the determination unit of the control unit 100 determines the number of the unit cell in which the abnormality has occurred. Is stored in the memory, and at the same time, 1 is set in the NG flag.
[0026]
Note that, after the transistor Tij of the odd-numbered capacity adjustment circuit is turned off in Step 190, the same processing as in Steps 150 to 190 described above is performed on the even-numbered capacity adjustment circuit 5 in Steps 200 to 250.
[0027]
In FIG. 3, capacity adjustment currents Id12 and Id14 are currents flowing through the capacity adjustment circuits corresponding to the cells C12 and C14, and are generated when the even-numbered stage is turned on. The minute impedance r seen in FIG. 3 is detected by the diagnosis of the capacitance adjustment circuit 5 of C12.
[0028]
In step 255, if the NG flag is 1, that is, if an abnormality is found in step 180 or 240 and 1 is stored in the NG flag, step 270 is executed.
[0029]
If the NG flag is 0, the routine proceeds to step 260 where it is confirmed that there is no circuit abnormality.
[0030]
In step 270, the determination unit of the control unit 100 confirms whether or not an abnormality occurrence place is adjacent to the odd and even stages. If the locations where the abnormality occurs are adjacent to each other, it can be understood that there is an abnormality in the connection circuit 7 of each single cell, that is, the unit cell Cij, the cell voltage measuring line 2 and the capacity adjustment circuit 5. This is because, as seen in FIG. 3, the influence of a minute impedance is detected by adjacent single cells sharing a circuit.
[0031]
If it is not an adjacent unit cell, the routine proceeds to step 280, where it is determined that there is a high possibility that an abnormality has occurred in the diagnostic function itself.
[0032]
When it is determined that there is an abnormality, a display unit or an alarm unit (not shown) notifies that there is an abnormality, a corresponding portion of the abnormality, and the like.
[0033]
Second Embodiment Next, an embodiment in which diagnosis is performed every other two will be described.
[0034]
Since the difference between the second embodiment and the first embodiment is only the processing flow, this point will be described.
[0035]
Also in the second embodiment, measuring the open-circuit voltage of all the unit cells is the same as steps 110 to 140 in the first embodiment.
[0036]
Next, every two capacity adjustment circuits are diagnosed. Of transistors Tij, j = 3k + 1 (where k = 0 to (n−1) / 3), that is, T11, T14, T17... Are driven, thereby diagnosing every two capacitance adjusting circuits 5. I can do it. This corresponds to driving j = 3k + 1 transistors Tij out of the transistors Tij instead of the odd-numbered transistors Tij in steps 150 to 190 of the first embodiment.
[0037]
Next, the transistor Tij + 1 next to the transistor Tij is similarly driven. That is, T12, T15, T18. Thereby, it is possible to diagnose every two adjacent capacitance adjusting circuits 5.
[0038]
Finally, the adjacent transistor Tij + 2 is driven. That is, T13, T16, T19. As a result, every two adjacent capacitance adjusting circuits 5 can be diagnosed.
[0039]
By operating the transistors Tij in the above three groups, all the transistors Tij are driven, and all the capacity adjustment circuits 5 are diagnosed.
[0040]
The diagnosis result of each capacity adjustment circuit is the same as that in steps 260 to 290 of the first embodiment.
[0041]
Also in the second embodiment, the capacity adjustment current flows through the connection portion 7 between the cell, the voltage measurement circuit, and the capacity adjustment circuit, so that it is possible to find an abnormality in this portion.
[0042]
In the above-described embodiment, the capacity adjustment circuit 5 is diagnosed every other and every second. However, the present invention is not limited to this example, and at least one of them is not adjacent to each other. The capacity adjustment circuit 5 may be diagnosed every predetermined number.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a cell controller.
FIG. 2 is a flow chart of capacity adjustment circuit diagnosis according to the present invention.
FIG. 3 is a schematic diagram of a capacity adjustment circuit diagnosis.
FIG. 4 is a diagram showing a configuration of an embodiment.
FIG. 5 is a circuit diagram of a conventional cell controller.
FIG. 6 is a schematic diagram of a capacity adjustment circuit diagnosis of a conventional example.
[Explanation of symbols]
Cij: single cell, Rij: resistance, Tij: transistor CCi: cell controller BC: battery controller Idj; current r flowing during diagnosis r: impedance 100: control unit 2: cell voltage measurement line 3: signal line 4: communication line 5: capacity Adjustment circuit 6: Diagnostic voltage measurement line 7: Connection between the unit cell Cij and the cell voltage measurement line 2 and the capacity adjustment circuit 5

Claims (3)

Connect multiple cells in series,
A cell voltage measurement line connected in a shared state between the poles of each unit cell and between adjacent unit cells,
A capacity adjustment circuit that adjusts the capacity of the unit cell by connecting a discharge circuit consisting of a resistor and a switch connected in series to each unit cell in parallel, and turning on the switch;
While measuring the voltage of each single cell by the cell voltage measurement line, comprising a control unit for turning on and off the switch,
In the control part,
The switch of the capacity adjustment circuit of the assembled battery is driven every predetermined number so that the capacity adjustment circuit of at least one adjacent battery pack is not driven at the same time, and then the switch of the capacity adjustment circuit that is not driven is changed every predetermined number. A switch drive unit for driving;
A storage unit that measures and stores the voltage of each cell when driving the switch of the capacity adjustment circuit;
Memorize the open circuit voltage (V0ij) of each cell measured at the time of no load,
A voltage comparison unit that compares the voltage of each unit cell measured during driving of the switch of the capacity adjustment circuit stored in the storage unit with the open voltage (V0ij) of each unit cell to determine whether it is abnormal,
A diagnostic apparatus for an assembled battery, comprising: 2. The assembled battery diagnostic apparatus according to claim 1, wherein the predetermined number for driving the switch of the capacity adjustment circuit is one. The assembled battery diagnostic device according to claim 1, further comprising:
The circuit part determined to be abnormal is stored, and when a plurality of abnormal circuit parts are recognized, it is determined whether the abnormality is adjacent to each other, and when it is determined that the parts of the abnormal circuit part are adjacent to each other, It is characterized by having a judgment unit for judging that there is a possibility of a misdiagnosis when it is judged that there is a failure in the shared part of the cell voltage measurement line and the locations of the abnormal circuit parts are not adjacent to each other Diagnostic device for assembled battery.

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