JPH11150880A - Voltage-detecting device of assembled battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the voltage detection device of an assembled battery that can concurrently detect the voltage and current of each module, while inhibiting the increase in a circuit scale and a wiring scale. SOLUTION: A control circuit 1 allows A/D conversion circuits 5-9 to read an analog signal at the sometime and a digital signal to be read from the A/D conversion circuit 5-9 in time sequence. By reading each analog signal in batch, the analog signals read by the A/D conversion circuit 5-9 is converted into digital signals and are retained and the digital signals are read from the A/D conversion circuit 5-9 to the control circuit 1 in time sequence. Therefore, since a signal path from the A/D conversion circuits 5-9 to the control circuit 1 can be put together, wiring structure can be simplified. Also, since the control circuit 1 has a common data input port, the configuration of the control circuit 1 can also be simplified.

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 Patent Laying-Open No. 5-64377 discloses a method of individually detecting module voltages of a plurality of modules constituting an assembled battery composed of a large number of unit cells connected in cascade.
It has been proposed to detect the current of the assembled battery and to control the charging of the assembled battery for each module (consisting of a plurality of cells connected in cascade in succession).

In the detection of the remaining capacity of an assembled battery mounted on an electric vehicle or the like, it is general to perform the detection based on the voltage and current in terms of high precision detection. In order to reduce the loss, an assembled battery is formed by cascading several hundred cells, and the total voltage is extremely high, so that accurate detection is not easy. For example, if the voltage detection accuracy is 0.1% and the total voltage is 300 V, an error of 0.3 V will occur. However, since the terminal voltage of the unit cell is about 1.2 V, the unit voltage of the unit cell depends on the total voltage. It was difficult to check for defects and check the charging status.

[0004] For this reason, as described above, the assembled battery is divided into a plurality of modules, each module voltage is individually detected, and the sum of the voltages or the charging status or the like is determined by these module voltages. Monitoring of a discharge state has been conventionally proposed.

[0005]

However, in the case where the total voltage is detected by the above-described module voltage, an error occurs in the total voltage due to fluctuations in the battery voltage unless the respective module voltages are detected simultaneously. There was a problem that it would. Also, the charge state of each module is
Even in the case of estimating the module voltage and the current, a large error occurs unless each module voltage and the current are detected at the same time.

Although it is theoretically possible to extract each module voltage and current at the same time by providing each circuit in parallel, in practice, it is difficult to adopt it due to a remarkable increase in circuit scale and wiring scale. is there. The present invention has been made in view of the above problems, and an object of the present invention is to provide an assembled battery voltage detecting device capable of simultaneously detecting each module voltage and current while suppressing an increase in circuit scale and wiring scale. It is a problem to be solved.

[0007]

According to the first aspect of the present invention, a control circuit causes each A / D conversion circuit to simultaneously take in an analog signal, and , The reading of the digital signal from each A / D conversion circuit is performed in time sequence. More specifically, the present invention utilizes the fact that the A / D conversion circuit has a function of temporarily storing signals, and the analog signals read into each A / D conversion circuit by simultaneous reading of each analog signal are The signals are converted into digital signals and held, and these digital signals are read from each A / D conversion circuit to the control circuit in time sequence.

Therefore, according to this configuration, since the signal paths from each A / D conversion circuit to the control circuit are concentrated, the wiring structure is simplified, and the control circuit has a common data input port. Therefore, the configuration of the control circuit can be simplified. According to the structure of the second aspect, in the voltage detecting device for an assembled battery according to the first aspect, the total voltage of the assembled battery is taken in simultaneously with each module voltage.

In this way, if the sum of the voltages of the respective modules taken in at the same time is significantly different from the total voltage, it is determined that any one of the modules has a problem such as leakage. Can improve reliability. According to a third aspect of the present invention, in the voltage detecting device for an assembled battery according to the first aspect, the A / D conversion circuit reads an analog signal in synchronization with a clock pulse by input of a read command and performs A / D conversion of the analog signal. After performing the conversion, the digital signal converted by the subsequent input of the clock pulse is serially output, and the control circuit instructs each A / D conversion circuit to read the analog signal simultaneously, and then to each A / D conversion circuit. The clock pulses are transmitted in time sequence so that each A /
The digital signals from the D conversion circuit are sequentially output in time.

With this configuration, simultaneous reading and time sequential reading can be realized using a simple synchronous operation serial output type A / D conversion circuit without using a latch circuit or a sample hold circuit. Thus, the circuit configuration can be simplified.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the following examples. However, the present invention is not limited to the configuration of the following embodiment, and it is obvious that the present invention can be configured using a replaceable known circuit.

[0012]

[Embodiment 1] An embodiment of a voltage detecting device for an assembled battery according to the present invention will be described with reference to FIG. Reference numeral 1 denotes a CPU for controlling charging and discharging of a battery, 2 denotes a selector circuit for distributing a clock signal comprising a demultiplexer (hereinafter also referred to as a clock signal selector circuit), and 3 denotes a selector circuit for distributing a control signal comprising a demultiplexer (hereinafter referred to as a selector circuit). , A control signal selector circuit), 4 is a selector circuit for selecting digital signals comprising a multiplexer (hereinafter also referred to as a data selector circuit), 5 to 9 are A / D converter circuits, and 10 to 13 are differential amplifier circuits. , 14 are analog amplifier circuits, 15 is a current sensor,
Reference numerals 16 to 18 denote modules of the assembled battery 19, and each of the modules 16 to 18 is formed by cascading several tens of cells. Reference numeral 20 denotes a serial signal line group for connecting each of the selector circuits 2 to 4 and each of the A / D conversion circuits 5 to 9. In this embodiment, each signal line is a photocoupler (see FIG. (Not shown).

As can be seen from FIG. 1, the module voltage (analog signal) of the module 16 is converted into a signal voltage with respect to a predetermined common ground potential by the differential amplifier circuit 10 and then A
A / D conversion is performed by the / D conversion circuit 5. Similarly, the module
The module voltage (analog signal) of the module 17 is converted to a signal voltage with respect to a predetermined common ground potential by the differential amplifier circuit 11, A / D converted by the A / D conversion circuit 6, and The differential voltage (analog signal) is converted into a signal voltage with respect to a predetermined common ground potential by the differential amplifier circuit 12 and then A / D converted by the A / D conversion circuit 7. Also, the total voltage (analog signal) of the assembled battery 19 is
3, the signal voltage is converted into a signal voltage with respect to a predetermined common ground potential, and then A / D converted by the A / D conversion circuit 8. The current of the assembled battery 19 is converted into a signal voltage by the amplifier circuit 14 and then converted by the A / D conversion circuit 9. A / D conversion is performed.

The outputs of the A / D conversion circuits 5 to 9 are selected in time sequence by the data selector circuit 4 and read into the CPU 1 as a signal SIN. The A / D conversion circuits 5 to 9 are A / D conversion circuits of a synchronous operation serial output type. Conversion data, that is, a serial digital signal is output in synchronization with a clock pulse inputted after the digital signal is determined.

More specifically, as shown in FIG. 2, the A / D conversion circuit 5 has an analog input terminal to which an analog signal is input, and a data output terminal which outputs a digital signal which is a serial signal.
A control command input terminal to which a control command which is a serial signal is input, and a clock pulse input terminal to which a clock pulse for synchronization is input, and when a read command is input to the control command input terminal. The analog signal is read in synchronization with the edge of the clock pulse input to the clock pulse input terminal, and then, the input of the next clock pulse outputs an 8-bit serial digital signal. The other A / D conversion circuits 6 to 8 have the same structure.

A more detailed operation of the battery pack voltage detecting device will be described below. The CPU 1 outputs a clock pulse SCLK and an A / D conversion circuit selection signal SEL to the clock signal selector circuit 2, and outputs a control command signal SOUT such as a read command and an A / D conversion circuit selection signal SEL to the control signal selector circuit 3. Data selector circuit 4
And outputs an A / D conversion circuit selection signal SEL to the data selector circuit 4 to receive a serial digital signal.

(Simultaneous reading) The CPU 1 notifies the clock signal selector circuit 2 and the control signal selector circuit 3 that all of the A / D conversion circuits 5 to 9 are selected by the A / D conversion circuit selection signal SEL. , The control signal selector circuit 3 transmits a read command to all of the A / D converter circuits 5 to 9, the clock signal selector circuit 2 transmits a clock pulse SCLK to all of the A / D converter circuits 5 to 9,
The / D conversion circuits 5 to 9 read the analog signal in synchronization with the edge of the clock pulse input immediately after the input of the read command, convert the analog signal into an 8-bit digital signal, and hold it. At this time, the A / D conversion circuit selection signal SEL for selecting all of the A / D conversion circuits 5 to 9 is invalidated for the data selector circuit 4 inside the data selector circuit 4.

(Sequential output) Next, the CPU 1 notifies the selector circuits 2 to 4 that the A / D conversion circuit 5 is to be selected by the A / D conversion circuit selection signal SEL. Clock pulse SCLK is set to A
A / D conversion circuit 5 transmits the serial digital signal to the data selector circuit 4 in synchronism with the edge of the clock pulse SCLK. Since the A / D conversion circuit 5 is selected by the conversion circuit selection signal SEL,
The serial digital signal from the conversion circuit 5 is transmitted to the CPU 1.

Next, the CPU 1 notifies the selector circuits 2 to 4 that the A / D conversion circuit 6 is to be selected by the A / D conversion circuit selection signal SEL, and thereafter performs the same operation as described above to execute the A / D conversion. Converts the serial digital signal of the conversion circuit 6 into a CPU
1, and similarly, the serial digital signals of the respective A / D conversion circuits 7 to 9 are transmitted to the CPU 1. As described above, in the battery pack voltage detecting device of this embodiment, A
Using the digital data temporary holding function of the / D conversion circuits 5 to 9, the parallel reading and the sequential reading are performed, so that it can be realized without using an extra circuit such as a latch circuit or a sample hold circuit. And the simultaneous reading of each module voltage, total voltage and current can be realized with a simple configuration.

Thus, the simultaneous reading of each module voltage and current enables accurate estimation of the battery capacity in consideration of the internal resistance of the battery, and the simultaneous reading of each module voltage and the total voltage allows each module to be read simultaneously. Based on the difference between the total voltage and the total voltage, it is possible to easily determine whether the battery is defective or the like.

[0021]

Embodiment 2 Another embodiment will be described with reference to FIG. In this embodiment, the A / D conversion circuits 5 to 7 shown in FIG. 1 are replaced with one multi-channel A / D conversion circuit 21.
1 is replaced by a multi-channel A / D conversion circuit 21 and A / D conversion circuits 8 and 9 shown in FIG.
Are similarly multi-channel A / D conversion circuits 22 and 23
Is converted to

Although the circuit operation of this embodiment is basically the same, three multi-channel A / D conversion circuits 21
23 are operated in a time-sequential manner and in synchronism with each other in response to a command from the control signal selector circuit 4 through a serial signal line. So, first,
The module voltage, total voltage, and current of the module 16 are read simultaneously, and are transmitted to the CPU 1 in time sequence. Then, the module voltage, total voltage, and current of the module 17 are read simultaneously. This is transmitted to the CPU 1 in time sequence, and thereafter, this operation is repeated up to the module voltage of the module voltage 18.

(Modification) The serial signal line group employed in each of the above embodiments can be replaced with a parallel signal line.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of an assembled battery voltage detecting device according to a first embodiment.

FIG. 2 is a block diagram of an A / D conversion circuit 5 of FIG.

FIG. 3 is a block circuit diagram of the battery pack voltage detection device according to the first embodiment.

[Explanation of symbols]

1 is a CPU (control circuit), 2 to 4 are selector circuits (control circuits), 5 to 9 are A / D conversion circuits, 16 to 18 are modules, and 19 is an assembled battery.

Claims (3)

[Claims] An A / D for detecting a plurality of module voltages for individually A / D converting the module voltages of a plurality of modules constituting an assembled battery composed of a number of cascade-connected unit cells.
A D conversion circuit, an A / D conversion circuit for current detection for A / D conversion of the current of the assembled battery, and a digital value of each of the module voltages and currents by driving and controlling each of the A / D conversion circuits. And a control circuit for taking in an analog signal. The control circuit causes the A / D conversion circuits to simultaneously take in analog signals, and outputs digital signals from the A / D conversion circuits. A voltage detecting device for an assembled battery, wherein signals are read out in time sequence. 2. The voltage detecting device for an assembled battery according to claim 1, further comprising: an A / D conversion circuit for detecting a total voltage for A / D converting a total voltage of the assembled battery. A voltage detecting device for an assembled battery, wherein the module voltage and the total voltage of the assembled battery are simultaneously taken in. 3. The voltage detection device for a battery pack according to claim 1, wherein the A / D conversion circuit reads an analog signal in synchronism with a clock pulse in response to a read command and reads the analog signal.
After performing the / D conversion, the digital signal converted by the subsequent input of the clock pulse is serially output. The control circuit instructs each of the A / D conversion circuits to simultaneously read the analog signal, By transmitting clock pulses to the D conversion circuit in time sequence, each A /
A voltage detecting device for an assembled battery, which performs time-sequential output of a digital signal from a D conversion circuit.