JP3395952B2 - Voltage detector for assembled batteries for electric vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery voltage detecting device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 8-140204 discloses an output voltage of a module voltage detection circuit section for individually detecting module voltages of a plurality of battery modules constituting an assembled battery through a photo coupler element. A voltage detector for an assembled battery that transmits to a low-voltage signal processing circuit unit is proposed.

[0003]

However, in the above-mentioned conventional voltage detecting device for the assembled battery, each module voltage detecting circuit section individually supplies the circuit operating power from each battery module. Either the individual power supply method that is used or the total voltage power supply method that is commonly supplied with circuit operating power from the entire assembled battery is adopted. When used, this main battery has a large voltage fluctuation depending on the running and charging conditions, and therefore, whichever method is adopted, there was a concern that the operation reliability would be reduced when the capacity is low.

For accurate measurement of the capacity of each battery module, it is effective to detect the terminal voltage when the charge / discharge current is 0, that is, the open terminal voltage. However, the battery module itself is a module. In the former power supply method of supplying power for circuit operation to the voltage detection circuit section, the discharge current does not become 0, so the open circuit voltage cannot be measured accurately, and it is not easy to measure the open circuit voltage with high accuracy. There was a problem that it was not there.

Further, in the case of the latter power feeding system, there is a problem that the power consumption is large because the circuit operating power is supplied to each module voltage detection circuit section from the main battery, that is, the whole assembled battery. In this case, there is a problem in that variations in the power consumption of the module voltage detection circuit units cause variations in the capacities of the battery modules and inequalities in the deterioration of the batteries due to the variations.

The present invention has been made in view of the above problems, and it is possible to detect an open module voltage with higher accuracy, avoid unnecessary shortening of the life of a high-voltage assembled battery, and further, to reduce running power storage state. It is an object to be solved to provide a voltage detecting device for an assembled battery for an electric vehicle, which can stably detect a module voltage despite a large fluctuation.

[0007]

According to the voltage detecting device for an assembled battery of the present invention described in claim 1, for example, 300
The main battery for storing high-voltage running power such as V is divided into a large number of battery modules, and the module voltage of each battery module is detected by the module voltage detection circuit section, and then the signal processing circuit section. Is transmitted.

In this configuration, in particular, the circuit operating electric power of the module voltage detecting circuit section which processes different and high potentials is not input / output from the auxiliary battery but the main battery.
Via a DC-DC converter with a built-in edge transformer
The feature is that the power is supplied by the power supply. This will provide electrical isolation between the main battery and the auxiliary battery.
While ensuring, Modulation - can be detected Le voltage more accurately,
Unnecessary shortening of the life of the high-voltage assembled battery can be avoided, and moreover, stable detection of the module voltage can be performed in spite of a large change in the running power storage state.

Further, because the module voltage is not consumed, the amount of electricity stored in each battery module that generates this module voltage is not consumed.
It becomes possible to estimate the total voltage and the capacity based on the total voltage, and the circuit operating power of the module voltage detection circuit section can reduce the discharge current of the battery module, so that it is accurate especially when the load current is 0 or small. The open module voltage can be measured, which enables highly accurate capacity estimation. Incidentally, there is a close correlation between the open terminal voltage and the capacitance. In addition, since the battery pack is not supplied with power even after long-distance running where the amount of electricity stored in the battery pack significantly decreases, it is not affected by the voltage drop or capacity shortage, and particularly high-precision module voltage detection is required. Thus, the module voltage can be stably detected even when the storage amount of the battery pack is reduced.

Furthermore, the degree of consumption of each battery module varies due to the variation in the circuit operating power of the module voltage detecting circuit unit, and the deterioration of the battery modules does not become unequal. According to the configuration of claim 2, claim 1
In the voltage detection device for an assembled battery for an electric vehicle described above, the module voltage detection circuit unit further includes a plurality of differential voltage detection circuits that respectively detect module voltages of the plurality of battery modules adjacent to each other. The input / output isolated DC-D having a plurality of voltage detection blocks
The C converter is individually provided for each of the voltage detection blocks, and the power source voltages output by the input / output isolated DC-DC converters are different from each other in the plurality of batteries. It is characterized in that it is formed with the potential of the positive electrode or the negative electrode of the module as a reference individually .

By doing so, the circuit configuration can be further simplified even though the battery modules of the assembled battery have different potentials and extremely high voltages. According to the configuration of claim 3, in the voltage detecting device for an assembled battery for an electric vehicle according to claim 2, the input / output isolation is further provided.
Edge-type DC-DC converters have one primary winding and multiple
A common transformer constructed by winding the secondary winding around a common core.
And the primary winding powered by the auxiliary battery
Having a common oscillating circuit that applies alternating voltage to
As a feature, the auxiliary equipment battery power supply of the present invention
Simplified circuit configuration of electric main battery voltage detection circuit device
can do. In a preferred embodiment, the output of each voltage detection block is output to the signal processing circuit section through a photo coupler element . If so this, the output voltage of the voltage detection block despite having a high pressure and different DC potentials, the common and, subsequent signal processing circuit of the DC level of each signal voltage (reference potential) Low-voltage driving can be realized.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the configurations of the following embodiments, and it goes without saying that known circuits that can be replaced can be used.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a voltage detecting device for an assembled battery for an electric vehicle according to the present invention will be described with reference to FIGS. Figure 1
FIG. 4 is a block circuit diagram showing a voltage detection device of an assembled battery for an electric vehicle that converts each module voltage of the assembled battery 19 into a digital signal. Dynamic voltage detection circuits 201 to 220,
A / D conversion circuits 5-8 are shown. FIG. 2 is a block circuit diagram showing a signal flow of the voltage detecting device of FIG.

Reference numeral 1 is a microcomputer for controlling charge / discharge of a battery, 2
Is a selector circuit for distributing a clock signal (hereinafter also referred to as a clock signal selector circuit) including a demultiplexer, 3 is a selector circuit for distributing a control signal including a demultiplexer (hereinafter also referred to as a control signal selector circuit), and 4 is a multiplexer A selector circuit for selecting a digital signal (hereinafter also referred to as a data selector circuit), 5 to 10 are A / D conversion circuits, 201 to 220 and 13 are differential voltage detection circuits, 14 is an analog amplification circuit,
Reference numeral 15 is a current sensor, and 101 to 120 are battery modules (also simply referred to as modules) of the assembled battery 19. However, in FIG. 2, the battery modules 106 to 120,
Differential type voltage detection circuits 206 to 220, A / D conversion circuit 6
8 are omitted in the figure.

In FIG. 1, reference numeral 301 denotes an auxiliary battery for supplying electric power to a control device and an electronic device of an electric vehicle, and 300 denotes DC power supplied from the auxiliary battery 301, a required DC potential level and a required voltage. Power supply circuit for voltage detection block power supply (D
C-DC converter), 20a, 20b, 20c, 20
Reference numeral d is a photocoupler element that transmits the outputs of the A / D conversion circuits 5 to 8 to the microcomputer 1 while electrically insulating the outputs. Similarly,
The outputs of the A / D conversion circuits 9 and 10 are also transmitted to the microcomputer 1 by a photo coupler element (not shown).

Each of the battery modules 101 to 120 is made up of twelve unit cells connected in series. Battery module 1
01 has the highest module voltage and battery module 120 has the lowest module voltage. Reference numeral 20 denotes a serial signal line group that connects each selector circuit 2 to 4 and each A / D conversion circuit 5 to 10. In this embodiment, each signal line is a photocoupler element 2 for protecting the microcomputer 1.
0a, 20b, 20c, 20d and the like.

The A / D conversion circuits 5 to 10 are switching input type A / D conversion circuits each having 5 channel inputs.
Depending on the input switching signal, each A / D conversion circuit 5
Channel 10 is switched in synchronization. As can be seen from FIG. 1, the module voltage of the battery module 101 is converted into a signal voltage with respect to a predetermined reference potential 1 by the differential type voltage detection circuit 201 and then A / D converted by the A / D conversion circuit 5. To be done. Similarly, the module voltage of the battery module 102 is converted into a signal voltage with respect to a predetermined reference potential 1 by the differential voltage detection circuit 202, and then A / D is converted by the A / D conversion circuit 5.
A / D conversion is performed, the module voltage of the battery module 103 is converted into a signal voltage for a predetermined reference potential 1 by the differential voltage detection circuit 203, and then the A / D conversion circuit 5 performs A / D conversion.
The converted module voltage of the battery module 104 is converted into a signal voltage with respect to a predetermined reference potential 1 by the differential type voltage detection circuit 203, and then A / D converted by the A / D conversion circuit 5, and the battery module The module voltage of the module 105 is converted into a signal voltage for a predetermined reference potential 1 by the differential voltage detection circuit 205, and then A / D converted by the A / D conversion circuit 5.

Similarly, the module voltages of the battery modules 106 to 110 are input to the A / D conversion circuit 6 through the differential type voltage detection circuits 206 to 210, and the battery module 1
The module voltages 11 to 115 are the differential type voltage detection circuit 2
11 to 215 are input to the A / D conversion circuit 7, and the module voltages of the battery modules 116 to 120 are supplied to the A / D conversion circuit 8 via the differential type voltage detection circuits 216 to 220.
Entered in.

Further, the total voltage of the assembled battery 19 is converted into a signal voltage with respect to a predetermined common ground potential by the differential type voltage detection circuit 13 and then A / D converted by the A / D conversion circuit 9 to obtain the current of the assembled battery 19. Is A / D converted by the A / D conversion circuit 19 through the amplifier circuit 14 and output to the microcomputer 1 through a photo coupler element (not shown). A / D conversion circuit 5-1
The output of 0 is time-sequentially selected by the data selector circuit 4 and read into the microcomputer 1 as a signal SIN. A
A / D conversion circuits 5-10 are synchronous operation serial output type A /
In the D conversion circuit, the conversion data, that is, the serial digital signal is output in synchronization with the clock pulse input after the digital signal is determined.

More specifically, the A / D conversion circuit 5 receives an analog input terminal to which an analog signal is input, a data output terminal to output a digital signal which is a serial signal, and a control command which is a serial signal. It has a control command input terminal and a clock pulse input terminal to which a clock pulse for synchronization is input. When a read command is input to the control command input terminal, the edge of the clock pulse input to the clock pulse input terminal The analog signal is read in synchronism, and then an 8-bit serial digital signal is output when the next clock pulse is input.
The other A / D conversion circuits 6 to 10 also have the same structure.

A more detailed operation of the voltage detecting device for the assembled battery will be described below. The microcomputer 1 outputs the clock pulse SCLK and the A / D conversion circuit selection signal SEL to the clock signal selector circuit 2, and the control signal selector circuit 3
Control command signal SOUT and A / D such as read command
The conversion circuit selection signal SEL is output, the A / D conversion circuit selection signal SEL is output to the data selector circuit 4, and the serial digital signal is received from the data selector circuit 4.

(Simultaneous reading) The microcomputer 1 notifies the clock signal selector circuit 2 and the control signal selector circuit 3 that all of the A / D conversion circuits 5-10 are selected by the A / D conversion circuit selection signal SEL, As a result, the control signal selector circuit 3 sends the read instruction to the A / D conversion circuits 5-1.
0, the clock signal selector circuit 2 transmits the clock pulse SCLK to all A / D conversion circuits 5 to 10, and each A / D conversion circuit 5 to 10 inputs the edge of the clock pulse input immediately after the input of the read command. The analog signal is read in synchronism with, and it is converted into an 8-bit digital signal and held. At this time, the A / D conversion circuit 5
A / D conversion circuit selection signal SEL for selecting all of
Is invalidated in the data selector circuit 4 with respect to the data selector circuit 4.

(Sequential output) Next, the microcomputer 1 executes A / D
The selector circuit 2 to 4 is informed that the A / D converter circuit 5 is selected by the converter circuit selection signal SEL, whereby the clock signal selector circuit 2 transmits the clock pulse SCLK only to the A / D converter circuit 5. As a result, the A / D conversion circuit 5 outputs a serial digital signal to the data selector circuit 4 in synchronization with the edge of the clock pulse SCLK,
The data selector circuit 4 uses the A / D conversion circuit selection signal SEL
Since the A / D conversion circuit 5 is selected by
The serial digital signal from the D conversion circuit 5 is the microcomputer 1
Sent to.

Next, the microcomputer 1 notifies the selector circuits 2 to 4 that the A / D conversion circuit 6 is selected by the A / D conversion circuit selection signal SEL, and thereafter performs the same operation as described above to perform A / D conversion. The serial digital signal of the D conversion circuit 6 is transmitted to the microcomputer 1, and thereafter, the A / D conversion circuits 8 to 1 are similarly processed.
A serial digital signal of 0 is transmitted to the microcomputer 1.

The above series of operations is executed for the first input channel of the input switching type multi-input A / D conversion circuits 5-10. 5 for each channel input. Next, the differential voltage detection circuits 201 to 220 for detecting each module voltage of the assembled battery 19 will be described with reference to FIG.

In this embodiment, a total of 240 unit cells constituting the assembled battery 19 are divided into 20 battery modules 101 to 120 which are connected in series, and the battery modules 101 to 105 are the first. 1, the battery modules 106 to 110 constitute a second voltage detection block, the battery modules 111 to 115 constitute a third voltage detection block, and the battery module 116.
˜120 form a fourth voltage detection block.

The first voltage detection block has a reference potential 1 which is a first reference potential, the second voltage detection block has a reference potential 2 which is a second reference potential, and the third voltage detection block. Has a reference potential 3 which is a third reference potential, and the fourth voltage detection block has a reference potential 4 which is a fourth reference potential .

In this embodiment, the reference potential 1 is set to the low-side terminal voltage of the battery module 103 (the high-side terminal voltage of the battery module 104). 3 from the high potential side in each voltage detection block
The low side terminal voltage of the second battery module (2 from the low side)
The high-side terminal voltage of the second battery module) is set.

That is, in this embodiment, the reference potentials (constant potentials applied to one end of the input side resistance circuit network) of the differential type voltage detection circuits in the same voltage detection block are equalized, and the respective voltages are equal. Different reference potentials 1 to 1 for the detection block
4 is applied. Furthermore, the reference potentials 1 to 4 are set to intermediate potentials of the battery modules in the voltage detection block (values as close as possible to the intermediate value between the highest terminal voltage and the lowest terminal voltage). Battery module as 1-4
The terminal voltage is used.

FIG. 3 shows a circuit diagram of the differential type voltage detection circuit 201. 2011 is an input resistance r1, r2 and a feedback resistance r
An operational amplifier having f1, which is a battery module 101
Terminal voltage V1 on the high potential side and reference potential 1 (here, the terminal voltage V1 on the low potential side of the battery module 103 (the battery module 1
04 (set to the high-side terminal voltage) (V1
-V4) is detected.

Similarly, 2012 is an operational amplifier having input resistors r3 and r4 and a feedback resistor rf2, which is a difference (V1-V) from the terminal voltage V2 on the low potential side of the battery module 101.
4) and the reference potential 1 (here, battery module 1
The difference V1-V2 is detected by subtracting the low side terminal voltage of 03 (set to the high side terminal voltage of the battery module 104).

The positive and negative power supply voltages of the operational amplifiers 2011 and 2012 are positive power supply voltages because the potentials of the positive and negative input terminals of the operational amplifiers are substantially equal to the virtual ground potential, that is, the reference potential V4 in this embodiment. VH is the reference potential V4
A predetermined voltage (here, 7.5 V) is set higher, and the negative power supply voltage VL is higher than the reference potential V4 by a predetermined voltage (here, 7.
5V) It is sufficient to form a voltage set low.

The reference potential V 4 may be an intermediate potential between the highest potential V 1 and the lowest potential V 6 of this voltage detection block, and may be formed using a special voltage generating circuit. Other features of the circuit device of this embodiment will be described below. First, since the output voltages of all the differential voltage detection circuits having the same reference potential in the same voltage detection block are input to the same A / D conversion circuit of the sequential switching type, each battery module to be detected is detected. It is possible to realize the common use of the A / D conversion circuit and to greatly simplify the circuit configuration, although the voltage of the circuit is significantly different.

Further, the output signal of each A / D conversion circuit is output to the microcomputer 1 driven by a predetermined low power supply voltage through a photocoupler element (for example, 20a), so that the operating voltage of the voltage detection block in the preceding stage is set. In addition to eliminating the DC voltage difference of the output signal voltage of each A / D conversion circuit with a different power supply voltage, a single digital signal processing circuit (usually a CPU) that cuts high voltage and operates at low voltage Can be digitally processed.

The differential voltage detection circuits 201 to 22 described above.
0, the power supply voltage (V
A power supply voltage generation circuit (DC-DC converter) 300 that forms H, VL) will be described with reference to FIG. Reference numeral 301 denotes a low-voltage (12V) auxiliary battery that supplies auxiliary power to an electric vehicle, and DC voltage thereof is converted into AC power by an oscillation circuit 302, and four voltage detection blocks are passed through a transformer 303 having four secondary coils. Power supply circuit 304 for power supply
Power is being supplied to 307. That is, the oscillation circuit 302,
Transformer 303 and voltage detection block power supply power supply circuit 3
04 to 307 configure the DC-DC converter 300.

Since these four voltage detection block power supply circuits 304 to 307 have the same circuit configuration, the power supply circuit 3 for supplying the power supply voltage to the voltage detection block having the highest potential.
04 will be described below. The AC voltage applied from the transformer 303 is converted into a DC voltage by the rectifying / smoothing circuit 3041 and applied to the positive and negative power source terminals of the differential voltage detection circuits 201 to 205.

The feature of this embodiment lies in the following circuit configuration for generating the reference potential Vc1. Specifically, the constant voltage circuit 3042 and the Zener diode 3043 are connected in series, and a DC voltage is applied from the rectifying / smoothing circuit 3041. The output voltage of the constant voltage circuit 3042 is A /
The high-level power supply voltage VH ′ of the D conversion circuit 5 is set, and the constant voltage circuit 3
042 and Zener diode 3043 connected to A / D
The lower power supply voltage VL ′ of the conversion circuit 5 is set, and this lower power supply voltage VL ′ is further used as the differential voltage detection circuits 201 to 205.
Is supplied with the reference potential 1 = Vc1. The potential difference between the output voltage of the constant voltage circuit 3042 = the higher power supply voltage VH ′ of the A / D conversion circuit 5 and the reference potential 1 = Vc1 is set so that the voltage drop of the Zener diode 3043 becomes substantially equal.

In this way, A /
Constant voltage circuit 304 for applying a constant power supply voltage to the D conversion circuit 5
By simply adding one Zener diode 3043 to 2, it is possible to form a stable reference potential with much less potential fluctuation than using the high-side terminal voltage of the battery module 104. The voltage detection block power supply circuit 3
The power supply circuit 305 for power supply to the voltage detection block supplies the differential voltage detection circuits 206 to 211 in the same manner as 04 supplies power to the differential voltage detection circuits 201 to 205 and the A / D conversion circuit 5.
5 and the A / D conversion circuit 6 and the voltage detection block power supply circuit 306 is a differential type voltage detection circuit 211 to 21.
5 and the A / D conversion circuit 7, and the voltage detection block power supply circuit 307 supplies differential voltage detection circuits 216 to 22.
It is natural to power 0 and the A / D conversion circuit 8.

In FIG. 1, the reference potentials 1 to 4 are illustrated so that a predetermined module voltage is used. However, in practice, it is preferable that the reference potentials 1 to 4 have high stability.
As shown in FIG. 4, the voltage detection block power supply power supply circuit 30
4 to 307 is preferable. Further, this embodiment is different from the module voltage detection circuit section (differential type voltage detection circuit 201) for processing high potentials.
-220, A / D conversion circuits 5-8) circuit operating power is supplied from the auxiliary battery 30 instead of the main battery (assembled battery) 19.
The feature is that power is supplied from 1.

In this way, in the voltage detecting device for the battery pack for electric vehicles, the open module voltage can be detected with higher accuracy, and unnecessary life shortening of the high voltage battery pack 19 can be avoided. It is possible to stably detect the module voltage in spite of a large change in the traveling power storage state. Further, in order to detect the module voltage, each battery module 101 to 12 that generates this module voltage.
Since the amount of stored electricity of 0 is not consumed, highly accurate module voltage, total voltage and capacity estimation based on it are possible, and the circuit operating electric power of the module voltage detection circuit is a battery module. Since the discharge current of each of the modules 101 to 120 can be reduced, an accurate open module voltage can be measured particularly when the load current is 0 or small, which enables highly accurate capacity estimation. Incidentally, there is a close correlation between the open terminal voltage and the capacitance. In addition, since the battery pack 19 is not supplied with power even after long-distance running in which the amount of electricity stored in the battery pack 19 is significantly reduced, there is no influence of the voltage drop or capacity shortage, and particularly highly accurate module voltage detection is possible. The module voltage can be stably detected even when the required amount of charge of the battery pack is reduced.

Furthermore, due to variations in circuit operating power of the module voltage detection circuit unit, each battery module 101
The degree of consumption of ~ 120 does not vary and the deterioration of the battery module does not become unequal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an assembled battery voltage detection device for converting each module voltage of the assembled battery 1 into a digital signal.

FIG. 2 is a block circuit diagram showing an embodiment of a battery monitoring device for an assembled battery using the assembled battery voltage detection device of FIG.

FIG. 3 is a block circuit diagram of an A / D conversion circuit 5 of FIG.

4 is a block circuit diagram of a power supply circuit that supplies power to the A / D conversion circuit 5 and the differential voltage detection circuit 201 of FIG.

[Explanation of symbols]

Reference numeral 1 is a microcomputer (signal processing circuit section), 19 is an assembled battery (main battery), 101 to 120 are battery modules, 201
To 220 are differential voltage detection circuits (module voltage detection circuit section), 5 to 10 are A / D conversion circuits (module voltage detection circuit section), 20a to 20d are photocoupler elements, 30
0 is a DC-DC converter, and 301 is an auxiliary battery.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // B60R 16/02 670 B60R 16/02 670S G01R 19/165 G01R 19/165 M (58) Fields investigated (Int.Cl. ⁷ , DB name) G01R 19/00-19/32 B60L 3/00 H01M 2/10 H01M 10/42 H02M 3/28 B60R 16/02 670

Claims (3)

(57) [Claims] 1. A module for individually detecting a module voltage of each battery module of a main battery for storing electric power for running electric power, which is composed of a high-voltage assembled battery in which a large number of battery modules are cascade-connected to each other. A voltage detecting device for an assembled battery for an electric vehicle, comprising: a voltage detecting circuit unit; and a signal processing circuit unit for signal processing each of the module voltages, wherein an auxiliary device for driving an auxiliary device equipped separately from the main battery. An input / output insulation type DC-DC converter for converting the voltage of the battery to DC / DC through a built-in transformer and applying it to the module voltage detection circuit section as a power supply voltage is provided, and the module voltage detection circuit section is provided. A power supply voltage is applied from the DC-DC converter to detect a potential difference between the positive and negative electrodes of the battery module as the module voltage, and the DC-DC converter outputs the voltage. That the power supply voltage,
Based on the positive or negative potential of the battery module
A voltage detecting device for an assembled battery for an electric vehicle, which is characterized by being formed . 2. The voltage detection device for an assembled battery for an electric vehicle according to claim 1, wherein the module voltage detection circuit section detects a plurality of differential voltages of the plurality of battery modules adjacent to each other. A plurality of voltage detection blocks each including a voltage detection circuit, the input / output isolated DC-DC converters are individually provided for the voltage detection blocks, and the input / output isolated DC-DC converters are provided individually. The power supply voltage output by the converter is the positive or negative potential of the plurality of battery modules belonging to the different voltage detection blocks.
An assembled battery voltage detection device for an electric vehicle, which is formed individually as a reference . 3. The voltage detecting device for an assembled battery for an electric vehicle according to claim 2, wherein each of the input / output isolated DC-DC converters has one primary winding and a plurality of secondary windings in common. An assembled battery for an electric vehicle, comprising: a common transformer wound around a core; and a common oscillator circuit that is supplied with power from the auxiliary battery and applies an AC voltage to the primary winding. Voltage detection device.