JP3803992B2 - Battery management device for assembled batteries for electric vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery management device for an assembled battery for an electric vehicle.
[0002]
[Prior art]
In recent years, as for assembled batteries for electric vehicles, a high voltage of 300 V or higher has been studied in order to reduce wiring loss and to reduce the size of an element for switching charge / discharge current.
In such a high-voltage assembled battery, the variation in the charge / discharge state of each single battery constituting the assembled battery becomes a problem, and even if it is estimated that the remaining capacity of the assembled battery as a whole is sufficiently large at the time of discharge, Some cells may be overcharged, i.e. fully charged, even if it is presumed that the battery is overcharged, i.e. undercharged, or on the contrary, it is estimated that the assembled battery is not fully charged as a whole. Arise.
[0003]
For this reason, Japanese Patent Application Laid-Open No. 5-64377 and Japanese Patent Application Laid-Open No. 8-140204 divide the assembled battery into a battery module group composed of a large number of cascaded single cells, and charge / discharge voltage for each battery module unit. It is proposed to monitor the battery and manage the battery.
According to this battery management method, the assembled battery can be charged / discharged in units of each battery module, which is a smaller battery block, so the above-mentioned problems such as overcharge, overdischarge, and failure of some single cells are avoided. It can be suppressed well.
[0004]
On the other hand, battery management such as calculation of the remaining capacity of the entire assembled battery is performed using the total voltage of the assembled battery. This is because the total module voltage obtained by adding up the module voltages is calculated from both terminals of the assembled battery at once due to the accumulation of various noises and offset errors related to detection, calculation, and addition of each module voltage. This is because it becomes less accurate than the total voltage.
[0005]
[Problems to be solved by the invention]
As described above, in battery management of a conventional assembled battery for an electric vehicle, a certain type of battery management process is performed using each module voltage, and a certain type of battery management process is performed using the total voltage of the assembled battery. They are independent of each other.
However, if an abnormality is detected in either battery management processing using module voltage (hereinafter also referred to as module voltage processing) or battery management processing using total voltage (also referred to as total voltage processing), depending on the degree of abnormality In the end, measures are taken to ensure safety by implementing countermeasures at each stage including electric vehicle travel prohibition (discharge prohibition) and charge prohibition, but in such cases, the following problems may occur: all right.
[0006]
In other words, if an abnormality occurs in a part of the detected module voltage or the total voltage, it may be an abnormality in the assembled battery, but these other voltages are detected in analog, converted into digital signals, and a signal processing unit. The malfunction of battery voltage processing circuits such as the module voltage processing circuit and the total voltage processing circuit to be taken in is often an abnormality in the wiring that connects the assembled battery and these circuits, or the wiring that outputs signals from these circuits. is there.
[0007]
In such a case, although the assembled battery itself has the ability to travel sufficiently, the overall control of the electric vehicle that receives the output signal as a result of the battery management processing from these battery voltage processing circuits, etc. The electronic control unit (ECU) that performs control erroneously determines that the entire battery or a part of the battery is seriously defective, and prohibits traveling.
[0008]
In particular, the above-described increase in the voltage of the assembled battery requires a significant increase in the configuration of the battery voltage detection circuit, and the failure probability of the battery voltage detection circuit is expected to increase accordingly.
The present invention has been made in view of the above problems, and in a battery management device for an assembled battery for an electric vehicle that processes the total voltage and module voltage of the assembled battery, while avoiding complication of the circuit configuration, the battery voltage detection failure It is an object of the present invention to provide a battery management device for an assembled battery for an electric vehicle that can suppress the deterioration of the function of the electric vehicle.
[0009]
[Means for Solving the Problems]
According to the battery management apparatus for an assembled battery for an electric vehicle of the present invention described in claim 1, each module voltage and total voltage of the assembled battery for an electric vehicle are detected, and the state of the battery module is related to each module voltage. The module state information is output, and the assembled battery overall state information relating to the state of the entire assembled battery is output based on the total voltage.
[0010]
In this configuration, in particular, it is determined whether or not at least some of these detection voltages are erroneously detected, and when an erroneous detection occurs, the state information on which the erroneous detection has occurred is corrected and normalized.
In this way, by detecting and processing each module voltage in addition to the total voltage of the assembled battery, detailed battery management can be performed, and even when these voltage detection circuits are partially broken, safety is ensured. While avoiding the deterioration, it is possible to minimize the deterioration of the function, and the usability for the electric vehicle can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail by the following examples. However, the present invention is not limited to the configurations of the following embodiments, and can naturally be configured using a replaceable known circuit.
[0012]
[Example 1]
An embodiment of a battery management apparatus for an assembled battery for an electric vehicle according to the present invention will be described with reference to FIG.
Reference numeral 1 denotes an assembled battery constituting a main battery for feeding electric power to a traveling motor of an electric vehicle, which is divided into 101 to 120 battery modules connected in series with each other.
[0013]
Reference numeral 201 denotes a module voltage detection circuit that detects voltages of the battery modules 101 to 120, that is, a total of 20 module voltages. The module voltage detection circuit 201 detects voltage of 20 channels in total that detects each module voltage independently of each other. Each voltage detection unit includes a differential amplifier (not shown) for detecting a potential difference between a pair of input potentials, and an A / D conversion circuit (A / D conversion circuit for A / D converting the detected potential difference). The output signals of these A / D conversion circuits are unified in a time sequence at the output stage of the module voltage detection circuit 201 and output.
[0014]
Reference numeral 202 denotes a total voltage detection circuit that detects the total voltage of the assembled battery 1 and has one voltage detection unit described above.
Reference numeral 5 denotes an electronic control unit (ECU) that controls various operations including charging / discharging of the assembled battery 1 based on the input module voltage and total voltage, and various information input from various sensors of the electric vehicle. .
[0015]
Reference numerals 301 and 302 denote input / output insulation type DC / DC converters for individually supplying power supply voltages to the module voltage detection circuit 201 and the total voltage detection circuit 202. These DC / DC converters 301 and 302 are low voltage not shown. Power is supplied from the auxiliary battery.
Reference numeral 401 denotes a photocoupler provided on a serial signal line for sequentially transmitting a total of 20 module voltages detected by the module voltage detection circuit 201, and 402 is detected by the total voltage detection circuit 202. It is a photocoupler provided on a serial signal line for transmitting the total voltage.
[0016]
What is important in this embodiment is that the module voltage detection circuit 201 and the total voltage detection circuit 202 are completely separated from each other, including input and output, from the power supply, so that one circuit failure does not affect the other. It is.
Next, the main part of the battery management routine by the electronic control unit (ECU) will be described with reference to the flowchart shown in FIG.
[0017]
First, a total of 20 module voltages are read from the module voltage detection circuit 201 (S100), and then the total voltage is read from the total voltage detection circuit 202 (S102).
Next, it is checked whether or not each read module voltage and total voltage are within the allowable range (S104). When only one of the module voltages is abnormal and the other module voltage and total voltage are normal The abnormal module voltage is replaced with the correction module voltage (S106), a module voltage abnormality warning signal is output (S108), the process proceeds to S110, and in S104, the process directly jumps to S110 in other cases. To do.
[0018]
In S110, it is checked whether or not each read module voltage and total voltage are within the allowable range. If only the total voltage is abnormal and all the module voltages are normal, the abnormal total voltage is corrected. The total voltage is replaced (S112), a total voltage abnormality warning signal is output (S114), the process proceeds to S116, and otherwise the process jumps directly to S116 in S110.
[0019]
In S116, it is checked whether or not at least one of the read module voltages and the total voltage are both abnormal. If both are abnormal, the battery abnormality is notified and the running operation (discharge operation) and the charging operation are prohibited. (S118) The routine is stopped, and if at least one of the module voltages read in S116 and the total voltage are not abnormal, the process proceeds to the next battery management operation or charge / discharge control operation (S120).
[0020]
In S104, if the detected value of the read module voltage is higher than the module voltage value at full charge by a predetermined voltage value or higher, or if the remaining capacity is 0, the module voltage error is lower than the module voltage value by a predetermined voltage value or more. However, the predetermined voltage value can be adjusted based on the read total voltage.
In S110, when the detected value of the read total voltage is higher than the total voltage value at full charge by a predetermined voltage value or lower than the total voltage value when the remaining capacity is 0, the total voltage abnormality is detected. However, the predetermined voltage value can be adjusted based on the total of the read module voltages.
[0021]
In S106, the erroneously detected module voltage is compensated. This compensation is performed by substituting the value of 1/20 of the total voltage or the total of the remaining module voltages other than the erroneously detected module voltage from the total voltage. A method such as deduction can be employed. Furthermore, it is also possible to simply output a determination signal meaning that all module voltages are OK.
[0022]
In S112, the erroneously detected total voltage is compensated. This compensation is performed by replacing with the total of the read module voltages. Further, only the determination signal meaning the total voltage OK is output. But you can.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of a battery management device for an assembled battery for an electric vehicle according to the present invention.
FIG. 2 is a flowchart showing a detection voltage check operation of the ECU of FIG. 1;
[Explanation of symbols]
201 is a module voltage detection circuit (module voltage detection means), 202 is a total voltage detection circuit (total voltage detection means), 5 is an ECU (module voltage processing means, total voltage processing means, erroneous detection determination means, correction means), S120 Are module voltage processing means and total voltage processing means, S104 and S110 are false detection determination means, and S106 and S112 are correction means.

Claims (1)

Module voltage detection means for detecting each module voltage of the assembled battery formed by cascading a large number of battery modules;
Total voltage detecting means for detecting the total voltage of the assembled battery at a time;
Module voltage processing means for outputting module state information relating to the state of the battery module based on each detected module voltage;
Total voltage processing means for outputting overall assembled battery state information relating to the state of the entire assembled battery based on the detected total voltage;
Erroneous detection determination means for determining the presence or absence of erroneous detection of either the module voltage or the total voltage based on each detected module voltage and the total voltage;
Correction means for correcting the output of the processing means for processing the voltage of the processing means that has caused the false detection during the erroneous detection determination;
The battery management apparatus of the assembled battery for electric vehicles characterized by the above-mentioned.

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