JP2003115332A - Voltage detecting device of assembling-type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage detecting device of an assembling-type battery in which a simultaneous detection of module voltage and current is possible while augmentations of a circuit scale and a wiring scale are inhibited. SOLUTION: A control circuit 1 simultaneously makes a read of an analog signal carried out at respective A/D conversion circuits 5, 9, and makes a read of a digital signal carried out from the respective A/D conversion circuits 5, 9 in the time sequence. That the respective A/D conversion circuits 5, 9 have a temporary retaining function of the signals is utilized, so that the analog signals of the module voltage and the current are simultaneously read, and the analog signals to be read in the respective A/D conversion circuits 5, 9 are converted and retained into digital signals, and read from the respective A/D conversion circuits 5, 9 to the control circuit 1 in the time sequence. Therefore, a signal path from the respective A/D conversion circuits 5, 9 to the control circuit 1 is integrated so that the wiring construction is simplified, and a composition of the control circuit 1 can be simplified also.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery voltage detecting device. 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 number of cascaded unit cells.
It has been proposed to detect the current of the assembled battery and control the charging of the assembled battery for each module (consisting of a plurality of cells connected in cascade in succession). [0003] In detecting 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 accuracy detection. In order to reduce the loss, several hundred cells are connected in cascade to form an assembled battery. Since the total voltage is extremely high, accurate detection is not easy. For example, if the voltage detection accuracy is 0.1% and the total voltage is 300V, an error of 0.3V will occur. However, since the terminal voltage of the unit cell is about 1.2V, the unit voltage of the unit cell depends on the total voltage. It was difficult to check for defects and check the charging status. For this reason, as described above, it is conceivable to divide the assembled battery into a plurality of modules, individually detect the voltage and current of each module, and monitor the state of charge and the state of discharge. However, when estimating the state of charge of each module using the module voltage and the current, a large error occurs unless the module voltage and the current are detected simultaneously. Will occur. 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 employ 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 detection device capable of simultaneously detecting each module voltage and current while suppressing an increase in circuit scale and wiring scale. It is an issue to be solved. According to the voltage detecting device for an assembled battery of the present invention, in order to detect the charging state of each module, the voltage and current of each module are detected. The values can be measured at the same time, and errors in the total voltage can be reduced due to fluctuations in the battery voltage. In addition, since the A / D conversion circuit for detecting the module voltage and the signal path from the A / D conversion circuit for detecting the current to the control circuit are integrated, the wiring is reduced and the configuration is simplified. Can be. Furthermore, each A / D conversion circuit can send a digital signal to a control signal without including a CPU, and the configuration of the control circuit can be simplified. [0008] Preferred embodiments of the present invention will be described in detail below 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. [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 / discharging of a battery, 2 denotes a selector circuit for clock signal distribution comprising a demultiplexer (hereinafter also referred to as a clock signal selector circuit), and 3 denotes a selector circuit for control signal distribution comprising a demultiplexer (hereinafter referred to as a clock signal 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 conversion circuits, and especially 5 to 7 of them.
Is an A / D converter for detecting module voltage, 8 is an A / D converter for total voltage, 9 is an A / D converter for current, 10 to 10
Reference numeral 13 denotes a differential amplifier circuit, 14 denotes an analog amplifier circuit, 15 denotes a current sensor, 16 to 18 denote modules of an assembled battery 19, and modules 16 to 18 cascade-connect dozens of cells, respectively. Do it. 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;
A photocoupler (not shown) is provided to protect U1. As can be seen from FIG. 1, the module voltage (voltage analog signal) of the module 16 is applied to the differential amplifier circuit 1.
At 0, the signal is converted to a signal voltage corresponding to a predetermined common ground potential, and then A / D converted by the A / D conversion circuit 5. Similarly, the module voltage (voltage analog signal) of the module 17 is converted by the differential amplifier circuit 11 into a signal voltage corresponding to a predetermined common ground potential, and then A / D converted by the A / D conversion circuit 6 to be converted. The module voltage (voltage analog signal) of the module 18 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. Further, the total voltage (total voltage analog signal) of the assembled battery 19 is converted into a signal voltage with respect to a predetermined common ground potential by the differential amplifier circuit 13, and then A / D converted by the A / D conversion circuit 8. The current (current analog signal) is converted into a signal voltage by the amplifier circuit 14 and then converted to an A / D converter circuit 9.
Is A / D converted. 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 synchronous operation serial output type A / D conversion circuits, and conversion data, that is, a serial digital signal is output in synchronization with a clock pulse input 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 inputted, and a clock pulse input terminal to which a clock pulse for synchronization is inputted, and when a read command is inputted 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 3 transmits a read command to all the A / D converters 5 to 9, the clock signal selector 2 transmits a clock pulse SCLK to all the A / D converters 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 responds to the A / D conversion circuit selection signal SEL by using the A / D converter module detection signal SEL.
The selector circuit 2 notifies the selector circuits 2 to 4 of the selection of the / D conversion circuit 5, whereby the clock signal selector circuit 2 transmits the clock pulse SCLK only to the A / D conversion circuit 5,
As a result, the A / D conversion circuit 5 outputs the clock pulse SCLK
A serial digital signal is output to the data selector circuit 4 in synchronization with the edge of the A / D converter circuit 4. The data selector circuit 4 selects the A / D converter circuit 5 by the A / D converter circuit selection signal SEL. The serial digital signal from the D 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 for detecting the module voltage is selected by the A / D conversion circuit selection signal SEL. An operation is performed to transmit a serial digital signal of the A / D conversion circuit 6 to the CPU 1, and similarly, each A
The serial digital signals of the / D conversion circuits 7 to 9 (7 are for detecting the module voltage, 8 is for detecting the total voltage, and 9 is for the A / D conversion circuit for detecting the current) are transmitted to the CPU 1.
As described above, in the assembled battery voltage detecting device of this embodiment, one of the A / D conversion circuit for detecting the module voltage and the A / D conversion circuit for detecting the current is selected and the A / D conversion circuit is selected.
The digital signal held by the / D conversion circuit is transmitted to a control circuit, and the control circuit transmits the other of the A / D conversion circuit for detecting the module voltage and the A / D conversion circuit for detecting the current. By selecting the A / D conversion circuit and transmitting the digital signal held by the A / D conversion circuit to the control circuit, the reading of the digital signal of each of the module voltage and the current is performed in time sequence. I have. That is,
Using the digital data temporary holding function of the A / D conversion circuits 5 to 9, parallel reading and sequential reading are performed, so that it is realized without using extra circuits such as a latch circuit and a sample hold circuit. It is possible to simultaneously read each module voltage, total voltage and current 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. 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 converted to 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 selected and operated in a time-sequential manner and in synchronization with each other in accordance with 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 a battery pack 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 a voltage detector for a battery pack according to the first embodiment. DESCRIPTION OF REFERENCE NUMERALS 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 (1)

Claims: 1. A module voltage detecting device for individually A / D converting module voltages of a large number of modules constituting a battery pack composed of a large number of unit cells of a cascade connection type. A / D
A 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 voltage and the current by driving and controlling each of the A / D conversion circuits. And a control circuit for reading the voltage analog signal of the module voltage into the A / D conversion circuit for detecting the module voltage, and controlling the current for detecting the current. A signal for causing the A / D conversion circuit to simultaneously read the current analog signal of the current is transmitted. The A / D conversion circuit for detecting the module voltage reads the voltage analog signal and converts it to a digital signal. The current detection A / D conversion circuit reads the current analog signal, converts it into a digital signal and holds it, and the control circuit detects the module voltage detection And selecting one of the A / D conversion circuit for current detection and the A / D conversion circuit for current detection, and transmitting the digital signal held by the A / D conversion circuit to a control circuit. The control circuit includes an A for detecting the module voltage.
By selecting the other one of the A / D conversion circuit and the current detection A / D conversion circuit, and transmitting the digital signal held by the A / D conversion circuit to the control circuit. And a digital signal of each of the module voltage and the current is read.