JPH07311248A - Deteriorated battery detector for assembled battery - Google Patents

Abstract

PURPOSE:To provide a deteriorated battery detector for an assembled battery which can detect and extract a deteriorated single cell by a simple system in the assembled battery having a plurality of single cells to be used, for exam ple, as the power source of an electric motor vehicle. CONSTITUTION:A deteriorated battery detector 12 comprises a switching unit 23 which has measuring terminals 211-21n clip connected to the terminals of single cells 131-13n for constituting a power source battery 13. The unit 23 has a voltage converter 24 for selecting the two measuring terminals to measure the voltage therebetween, to measure the open terminal voltage of the cells 131-13n in the state that the cells 131-13n are fully charged, and to extract to store the cell having a high deterioration possibility. Then, a motor 14 is driven to obtain a predetermined discharge current from the battery 13. It measured the terminal voltage of t,he cell having the high deterioration possibility, and judges a battery to be deteriorated in the state that a voltage drop obtained based on the discharge voltage is a predetermined value or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery composed of a combination of a plurality of unit cells constituting a power source for an electric vehicle, for detecting deterioration of each unit cell constituting the assembled battery. The present invention relates to a deteriorated battery detection device for assembled batteries.

[0002]

2. Description of the Related Art In an electric vehicle, an electric motor is used as a drive source for the electric vehicle. As a power source for the driving motor, for example, an assembled battery in which a large number of unit cells are connected in series is used. As a unit cell that constitutes such an assembled battery, a lead battery is generally used, but if a deteriorated battery is mixed in the unit cells that constitute such an assembled battery, The performance of the entire battery pack is reduced. For this reason, a deteriorated unit cell can be quickly detected from a large number of assembled batteries,
It is necessary to take measures such as replacing the deteriorated battery.

Here, there is no means for directly detecting the deterioration of each unit cell.
As disclosed in Japanese Laid-Open Patent Publication No. 59-59, the terminal voltage of each unit cell is measured, and the deterioration of the cell is determined by comparing it with a specified voltage for determining normality, or the temperature of the electrolytic solution is Deteriorated batteries are detected by measuring the specific gravity.

However, in an electric vehicle or the like, for example, 1
An assembled battery is composed of a combination of zero or more single cells. Therefore, it is necessary to take out a terminal from each of these multiple single cells to measure the voltage, and to measure the temperature of the electrolyte solution of each of the multiple single cells. For measuring specific gravity, the device is very large scale. Therefore, the cost of the device for detecting the deteriorated battery increases.

The technology disclosed herein is intended mainly for a battery mounted in an automobile that uses an internal combustion engine as a power source, and has a certain extent such that a starter motor is operated when the internal combustion engine is started. It is effective when it is clear to discharge a large current.

However, in the case of an electric vehicle, almost no current flows when the engine is started, and the discharge current from the battery power source changes in the running state. In the device disclosed in Japanese Patent Laid-Open No. -20059, it is not possible to accurately detect the deterioration state of each of the unit cells forming the assembled battery. Further, in such an apparatus, a processing circuit is required for each single battery, and when the number of constituents of the single battery increases like in an electric vehicle, the insulation between the processing circuits set for each battery will be increased. It becomes necessary and the circuit becomes large-scale.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to easily detect a deteriorated battery from a large number of cells constituting an assembled battery in, for example, an automobile dealer or a maintenance plant. Therefore, it is an object of the present invention to provide a deteriorated battery detection device for an assembled battery, which can inspect an assembled battery in a vehicle without considering the number of cells and the connection status which are different for each vehicle.

[0008]

According to another aspect of the present invention, there is provided a deteriorated battery detecting device for an assembled battery, wherein current detecting means is set in a power line output from an assembled battery composed of a plurality of arbitrarily connected cells. A plurality of measuring terminals are set corresponding to each of the unit cells, and the voltage of the selected measuring terminal of the plurality of measuring terminals is measured by the voltage measuring means.
Then, the fully-charged terminal voltage measuring means measures and stores the open terminal voltage of the plurality of cells when the battery is fully charged, and drives the load connected to the assembled battery to set the discharge current from the assembled battery. In the state that it is judged that it is within the range,
The terminal voltage at discharge is measured by the voltage measuring means to measure and store the open terminal voltage at discharge of each single cell, and the stored full-charge terminal voltage and the stored terminal voltage at discharge are respectively set to a specified voltage. A comparison is made and the deteriorated battery is identified based on the comparison result.

[0009]

In the deteriorated battery detecting device for the assembled battery constructed as described above, the measuring terminals are randomly connected to a plurality of cells mounted on the vehicle by a clip terminal structure or the like. Then, by connecting the voltage measuring means to the selected measuring terminal and sequentially measuring and comparing the voltages between arbitrary terminals, the order of connection of the single cells corresponding to the measuring terminal is obtained by the arrangement of the measured voltage values. The open terminal of each unit cell can also be specified. If the open terminal of each cell can be identified in this way, the terminal voltage of each cell will be measured and stored in the fully charged state of each cell, and the state of discharge from the assembled battery will be determined. The discharge terminal voltage of each unit cell is measured in the state confirmed by the current detecting means, and the discharge terminal voltage is measured and stored. Therefore, for example, the depleted battery is preliminarily detected by the open terminal voltage at the time of full charge. The voltage drop of each cell at the time of discharging is obtained from the difference from the voltage, and if it is determined that the voltage drop is equal to or more than a predetermined specified value, it is determined that the cell is deteriorated.
Therefore, with a very simple facility, by connecting the measurement terminals randomly to the cells mounted on the automobile, etc., the deteriorated battery can be reliably detected, which has a great effect on the efficiency of the maintenance work of the electric vehicle. To be demonstrated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows the configuration of an electric vehicle.
11 and a deteriorated battery detection circuit 12 are combined.
The electric vehicle 11 is equipped with a battery power source 13 as a power source. The battery power source 13 is, for example, n unit cells 131.
Each of the unit cells 131 to 13n is monitored by the deteriorated battery detection circuit 12 for its deterioration state.

The electric vehicle 11 is provided with a drive mechanism in which the rotational force of the motor 14 is transmitted to the wheels 16, which are drive wheels, via the transmission 15, and the output power from the battery pack 13 to the motor 14 is converted into an inverter. It is configured to be supplied via 17. Then, a clamp-type current sensor is provided for the power line 18 that supplies the output current from the battery pack 13 to the inverter 17.
19 is the one that can be selectively attached.
Is configured so that the discharge current from the battery power supply 13 is measured and the measured output is input to the deteriorated battery detection circuit 12.

Here, for example, clip type measurement lines 201 to 20n are selectively connected to the positive side terminal and the negative side terminal of each of the unit cells 131 to 13n connected in series which constitute the battery power source 13. . The measurement lines 201 to 20n are connected to the measurement terminals 211 to 21n set in the deteriorated battery detection circuit 12, respectively.
n is composed of, for example, a wire bundle, and randomly
It is clip-connected to the terminals of 1 to 13n, and the order of the battery connection order and the measurement terminals 211 to 21n is specified in the figure, but the mutual relationship is actually set at random.

Here, the number of constituent cells 131 to 13n of the assembled battery constituting the battery power source 13 mounted on the electric vehicle 11 is
It depends on the car model. Therefore, the number of measurement terminals 211 to 21n and measurement lines 201 to 20 set in the deteriorated battery detection circuit 12 are set.
The number of n is set according to the expected number of cells in the assembled battery.If the actual number of cells is less than the expected number of cells, measurement is not connected to cells. There are also terminals. In addition, the terminals set for each of the measurement lines 201 to 20n are clip-shaped and easily connected to the battery terminal section. Except for the part, it has an insulating structure.

In the deteriorated battery detection circuit 12, a measuring terminal
211 to 21n Select terminal 221 selectively connected to each
And 222, measuring terminals 211 to 21n and selecting terminal 221
And 222 form a switch 23. This switch 23 is designed to be freely switchable, and the selection terminals 221 and 222 are connected to the positive and negative inputs of the voltage converter 24, and between the selection terminals 221 and 222. Has a resistor 25 connected. That is, the measurement terminal 21
The voltage between the selection terminals 221 and 222, which is arbitrarily and selectively connected to 1 to 21n, is converted into voltage data in the voltage converter 24.

The voltage information measured by the voltage converter 24 is the current converter 25 to which the measured current value from the current sensor 19 is supplied.
Is supplied to the calculation / determination unit 26 together with the current value data from
The display 27 is driven by the output from the calculation / determination unit 26.

The deteriorated battery detecting operation of the device thus constructed will be described with reference to FIGS. 2 and 3. First, prior to this deteriorated battery detection operation, step 10 in FIG.
As shown by 0, the charging mechanism (not shown) set in the electric vehicle 11 causes the cells 131 to 13n of the battery power source 13 to be evenly fully charged. Then, as in step 101, connect the clamp-type current sensor 19 to the output power line of the battery power supply 13.
While being clamped to 18, the clips of the measurement lines 201 to 20n are connected to the terminals of the cells 131 to 13n, respectively.

In this way, the current sensor 19 is connected to the battery power source 13.
Is set, and the measurement line is set for each cell 131 to 13n.
When 201 to 20n are connected, the deterioration detecting operation of step 102 is started. In this deterioration detection operation, first, the switch 23 is activated to set the selection terminals 221 and 222 to 1
The second measurement terminal 201 and, for example, the nth measurement terminal 20n are connected and set. Then, the voltage measurement between the first measurement terminal 201 and all the other measurement terminals in step 103 is sequentially executed in the voltage converter 24.

That is, in this step 103, the deteriorated battery detection circuit 12 is operated, and the switch 23 is operated according to an instruction from the arithmetic / determination unit 26 to select the selection terminals 221 and 222.
Are respectively connected to the second measuring terminal 212 (the negative side terminal of the voltage converter 24) and the first measuring terminal 211 (the positive side terminal of the voltage converter 24), and the voltage between these measuring terminals 211 and 212 Is measured by the voltage converter 24. Arithmetic / judgment part
At 26, the measurement terminal 211 connected to the voltage converter 24
The open-circuit terminal voltage at the time of full charge of the unit cell 131 between 0 and 212 is input, and the measured voltage value is measured data (V1-2
) Is stored as.

Next, in accordance with an instruction from the arithmetic / determination unit 26, the measurement terminal 212 is left as it is and the third measurement terminal 213 is left.
And the selection terminal 221 are connected. That is, the measuring terminal 213 is connected to the positive side of the voltage converter 24, and the voltage between the first measuring terminal 211 and the third measuring terminal 213 in this state is measured. Then, the measured voltage data (V1-3) is stored. After that, the selection terminal 221 connected to the positive side of the voltage converter 24 is sequentially switched to the subsequent measurement terminals 214 to 21n, and the measured voltage data between the first measurement terminal 211 and each of the other measurement terminals ( V1-2, V1-3, V1-4,
...) is measured and stored.

In step 104, based on such measured voltage data, the unit cells 131 constituting the battery power source 13 are formed.
Determine the number of ~ 13n. Since the resistor 25 is connected between the selection terminals 221 and 222 during the switching operation of the switch 213, the voltage measurement data at the measurement terminal to which the unit cell is not connected is not affected by the resistance 25. It becomes 0V. Therefore, the calculation / determination unit 26 counts the number of voltage measurement data that is not 0 V, thereby counting the number of unit cells that form the power supply battery 13. Further, in the calculation / judgment unit 26, the voltage measurement data of the measurement terminal whose voltage measurement data is judged to be 0 V is judged to be invalid, and the corresponding voltage measurement data is erased.

In step 105, the connection order of the unit cells connected to the measurement terminals is determined based on the stored measured voltage data. That is, since the stored measured voltage data are all based on the voltage value detected at the first measuring terminal 211, this first measuring terminal
By comparing the measured voltage values between the 211 and the other measuring terminals 212 to 21n respectively,
The connection state of the unit cells 133 to 13n respectively connected to the 21n can be determined as follows.

That is, when the measured voltage data (V1-k) is a positive voltage, the unit cell connected to the kth measuring terminal 21k has a higher potential than the unit cell connected to the first measuring terminal 211. Is the unit cell connected to the higher one, (V1-k
) Is a negative voltage, the kth voltage measurement terminal 21k
It can be determined that the unit cell connected to is connected to the lower one than the unit cell connected to the first measurement terminal 211. Therefore, measuring terminal 211 and other measuring terminals 21
The result of arranging the voltage measurement data between 2 to 21n in the order of magnitude is the same as the connection order of the series-connected assembled battery of the unit cells to which the respective measurement terminals are connected.

That is, in the arithmetic / judgment unit 26, a plurality of stored voltage measurement data are arranged in order of size, and the numbers of the measuring terminals corresponding to the respective voltage measurement data are arranged in order of the unit cells 131 to 131. It is stored as the connection order of 13n. This order is used in the subsequent calculation determination process as the connection order of the unit cells 131 to 13n to which the measurement terminals 211 to 21n are connected in the assembled battery.

Specifically, when the stored voltage measurement data are ranked as "V1-k <... <V1-1 <V1-j <... <V1-m", each of the unit cells has The order corresponding to the unit cell connection order of the measurement terminals to be connected is "k, ..., 1, j, ...
m ”.

A unit cell that constitutes the power supply battery 13 in this manner
If the connection order of 131 to 13n is determined, the switch 23
At step 106, the measurement terminals to which the individual cells 131 to 13n are individually connected can be identified. In step 106, the open terminal voltage of each of the single cells 131 to 13n when fully charged is measured and stored.

Specifically, by the instruction from the arithmetic / judgment unit 26, the measurement terminal determined to have the lowest potential is connected to the negative side of the voltage converter 24, and the measurement determined to have the second lowest potential. Connect the terminal to the positive side of the voltage converter 24.
In the calculation / judgment unit 26, this first measurement terminal and
The voltage value between the second measuring terminal is read from the voltage converter 24, and this is stored as the open terminal voltage (U1) of the cell having the lowest potential in the power supply battery 13 constituted by the assembled battery.

Next, according to an instruction from the calculation / determination unit 26, 2
Connect the measurement terminal that is determined to have the second lowest potential to the voltage converter 24
Connected to the negative side of, and the measuring terminal determined to have the third lowest potential is connected to the positive side of the voltage converter 24, and the voltage between this second measuring terminal and the third measuring terminal is taking measurement. Then, this measured voltage value is stored as the open terminal voltage (U2) of the second lowest cell in the battery pack. After that, similarly, by sequentially switching the measurement terminals according to the voltage order, the open-circuit terminal voltage of each unit cell 131 to 13n at the time of full charge is measured, and the open-circuit terminal voltage (U1, U1, ... Un-1).

In step 107, the first judgment step is executed based on these stored data. It is known that the open-circuit terminal voltage of a fully charged battery is proportional to the specific gravity of the electrolyte solution of this battery, and therefore, based on the open-circuit terminal voltage of each cell, this The first step of determining the deterioration of each battery is executed.

That is, the open terminal voltage (U1
, U1, ..., Un-1) is compared with a standard value (specified voltage) corresponding to the open terminal voltage of a normal cell, and the cell showing an open terminal voltage lower than this standard value is deteriorated. The data (Uj, ..., Uk) of the open terminal voltage of the unit cell which is determined to have a high possibility of being deteriorated and is determined to have the possibility of deterioration in step 108 is stored. When the calculation / determination unit 26 completes the first determination step, the display 27 indicates that the first degradation determination step has been completed.

When the open terminal voltage at the time of full charge of each unit cell is measured and the first step of the determination for extracting the unit cell which may be deteriorated is completed, as shown in FIG.
Proceed to step 110 of. In this step 110, the first judgment
A cell with a high possibility of deterioration identified in the step is selected, and the switch 23 is operated so that the measurement terminal connected to the electrode portion of the selected cell is selected.
Accurate battery deterioration cannot be determined only by the deterioration determination based on the open terminal voltage. Therefore, the following discharge test is executed based on the determination result of the first determination step.

That is, in step 111, the drive wheels of the electric vehicle are jacked up so that they can rotate freely, and after actually setting the rotatable state of the motor 14 which is the drive source, the drive motor 14 is operated. , Battery power
Allow 13 to be set to the discharged state. Then, in step 112, the battery power supply for operating the drive motor 14
The discharge current from 13 is measured by the current sensor 19.

That is, the current converter 25 measures the output from the current sensor 19 at a specified sampling timing according to a command from the calculation / determination unit 26 and monitors the current value. It is determined whether or not the measured current value i is between the measurement lower limit value and the measurement upper limit value. For example, the rotation speed of the motor 14 is controlled by an accelerator operation or the like, and is measured by the current sensor 19. The discharge current value from the battery power source 13 is set within a predetermined set value range.

If it is determined in step 113 that the discharge current value is not within the set range, step 114
Proceed to and determine the end of the set time. If the set time has not ended, the process returns to step 112, and if it is determined that the set time has ended, the process proceeds to step 115 to display the retest and returns to step 110.

When it is judged at step 113 that the discharge current value i is within the set range, the routine proceeds to step 116, at which the terminal voltage of the unit cell is measured. Specifically, if it is determined in the first step of determination that the data of a single cell that is likely to be deteriorated is Uj, the j-th measurement is performed in step 116 when measuring the open terminal voltage for each measurement terminal. Switch the measurement terminal that is judged to have a low voltage
By driving 23, it is connected to the negative side of the voltage converter 24, and the measurement terminal determined to have the j + 1th lowest voltage is connected to the positive side of the voltage converter 24.

The voltage value converted by the voltage converter 24 in such a state is j in the assembled battery constituting the battery power source 23.
The cell with the second lowest potential (cell with a high possibility of deterioration)
It is stored as the battery voltage Wj at the time of discharging. This is the terminal voltage of a unit cell with a high possibility of deterioration when it discharges a current within the range of the specified value.

At step 117, it is judged whether or not the measurement of the terminal voltage at the time of discharging such a cell having a high possibility of deterioration is completed, and it is determined that the cell having a high possibility of deterioration still remains. When the determination is made, the process returns to step 110. In other words, if there are multiple cells with a high possibility of deterioration, specify the cell with the next highest possibility of deterioration and specify the switching device.
23 is activated, and similarly, the terminal voltage when the unit cell is discharged is measured and stored.

If it is determined in step 117 that the measurement of the terminal voltage at the time of discharging the single cell with a high possibility of deterioration has been completed, the process proceeds to step 118 to indicate that the discharge test is completed.
Display at 27, and stop the drive motor 14 at step 119. Then, the process proceeds to the second judgment step of step 120.

In the second step of this judgment, the voltage drop of each cell due to the difference between the open terminal voltage at the time of full charge and the terminal voltage at the time of discharge measured so far is compared with a set specified value. In the unit cell determined to have a high possibility of deterioration in the determination first step, the voltage drop due to this discharge is obtained based on the terminal voltage during discharge, and is compared with the specified value. When it is determined in step 120 that the voltage drop is smaller than the specified value, a determination display indicating that there is no deteriorated battery is displayed in step 121. And
If it is determined that the voltage drop is greater than the specified value,
Proceed to step 122, determine that the battery is degraded, and step 123
Display the measurement terminal to which this degraded battery is connected.

In the embodiment, the range of the voltage input to the voltage converter 24 is constant, but if the input voltage range is switched according to the voltage range to be measured, more accurate voltage measurement can be performed. This is possible, and the detection accuracy of the deteriorated battery is further improved.

[0040]

As described above, according to the deterioration detecting device for an assembled battery according to the present invention, for example, in an assembled battery composed of a plurality of cells mounted as a power supply device in an electric vehicle, it can be easily used in a dealer or a repair shop. Degraded batteries can now be detected, and it is easy to inspect battery packs that are in a vehicle without considering the number of cells and the connection status that differ from vehicle to vehicle. To be simplified.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a deteriorated battery detection device for an assembled battery according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a flow of a deteriorated battery detection processing operation of the above embodiment.

FIG. 3 is a flowchart illustrating a flow of processing operations subsequent to the processing of FIG.

[Explanation of symbols]

11 ... Electric vehicle, 12 ... Degraded battery detection circuit, 13 ... Power supply battery by assembled battery, 131 to 13n ... Single battery, 14 ... Motor, 15 ...
Gearbox, 16 ... Wheels, 17 ... Inverter, 18 ... Power line, 19 ...
Clamp type current sensor, 201 to 20n… Measurement line, 211 to 21
n ... Measurement terminal, 221, 222 ... Selection terminal, 23 ... Switch,
24 ... Voltage converter, 25 ... Current converter, 26 ... Calculation / judgment unit,
27 ... Indicator.

Claims (4)

[Claims] 1. A current detection unit that is set on a power line output from a battery pack composed of a plurality of arbitrarily connected single cells, and measures current output from the battery pack flowing through the power line, and the current detection unit. A plurality of measuring terminals set corresponding to each of the cells constituting the battery, a selecting means for selecting an arbitrary measuring terminal among the plurality of measuring terminals, and a selecting means connected to the selecting means. Voltage measuring means for measuring the voltage of the measuring terminal selected by the voltage measuring means, and fully-charged terminal voltage measuring means for measuring and storing the open terminal voltage of the plurality of cells constituting the assembled battery when the battery is fully charged. And a current value determination means for driving a load connected to the assembled battery to measure a discharge current from the assembled battery by the current detection means, and determining that the current value is within a set range. , A discharge terminal voltage measuring means for measuring and storing the discharge terminal voltage of each of the unit cells by the voltage measuring means in a state where the discharge current from the assembled battery is determined to be within the set range in this determination state. Then, the stored full-charge terminal voltage and discharge terminal voltage are respectively compared with the set specified voltage, and the deteriorated battery is identified based on the comparison result. Battery detection device. 2. A fully-charged terminal voltage measuring means constitutes a first determination step to detect a primary deteriorated battery, and to deal with a deteriorated battery selected in this primary deterioration detection step. Then, the discharge terminal voltage measuring means measures the discharge terminal voltage of the unit cell to obtain the voltage drop during the discharge, and the secondary deterioration detecting step is performed based on this voltage drop. The deteriorated battery detection device for an assembled battery according to claim 1. 3. The plurality of measurement terminals are configured and specified by a plurality of lead-out terminals that are arbitrarily clip-connected to the respective terminal portions of the individual cells that form the assembled battery.
The terminal voltage between one derived terminal and each of the other terminals is measured by the voltage measuring means, the connection order of each of the plurality of cells is determined based on the measured value, and each cell is determined based on the determination result. The deteriorated battery detection device for an assembled battery according to claim 1, wherein an open terminal voltage of each battery is measured. 4. The plurality of measurement terminals are configured by a plurality of randomly-arranged lead-out terminals that are arbitrarily clip-connected to the respective terminal portions of the individual cells constituting the battery pack, and are specified. The voltage measuring means measures the terminal voltage between one derived terminal and each of the other terminals, and comprises a computing means for recognizing the connection order of the plurality of cells. The deteriorated battery detection device for an assembled battery according to claim 1, wherein the measurement terminal corresponding to the terminal is specified.