JP6923840B2 - Battery voltage measuring device - Google Patents

Description

The present invention relates to a voltage measurement technique for a battery unit in an assembled battery.

Batteries used as power supply sources for driving motors of electric vehicles, plug-in hybrid vehicles, etc. are required to have high output, so a wide range of assembled batteries in which battery units such as lithium-ion batteries are combined at least in series are widely used. in use.
In a vehicle equipped with such a high-output assembled battery, if the output voltage of each battery unit varies due to use, a voltage equalizer that processes the output voltage of the battery unit to be uniform is provided. Many are installed. Then, in order to determine the necessity of voltage equalization processing by such a voltage equalizing device and to perform failure diagnosis processing of each battery unit, a device for measuring the voltage of each battery unit is required. ..

Patent Document 1 describes a voltage measuring device (voltage monitoring system) that measures the voltage of each battery unit in an assembled battery in which a plurality of battery units (battery cells) are arranged in series. In the voltage measuring device of Patent Document 1, a large number of battery units are divided into a plurality of groups, and each group is provided with a voltage measuring device (first monitor IC, second monitor IC).

Japanese Unexamined Patent Publication No. 2016-44986

By the way, in the voltage measuring device that measures the voltage of each battery unit, various processes such as voltage equalization processing performed based on the state of the assembled battery and various controls performed by the output from the assembled battery are performed on the load. It is required to measure the voltage of each battery unit at high speed to quickly grasp the state of the assembled battery so that it can be performed quickly and accurately in response to fluctuations in the temperature state.
However, even if the battery units are divided into a plurality of groups and a voltage measuring device is provided for each group as in Patent Document 1, if the number of battery units is large relative to the processing capacity of the voltage measuring device, all the batteries are used. It becomes difficult to measure and process the voltage of the unit at high speed. Further, although it is possible to measure and process the voltage of the battery unit at high speed by reducing the number of battery units per voltage measuring device, the number of voltage measuring devices must be increased, which causes an increase in cost. There is a problem such as.

The present invention has been made to solve such a problem, and an object of the present invention is to increase the voltage of the battery unit at high speed while suppressing an increase in cost in an assembled battery in which a plurality of battery units are combined in series. It is an object of the present invention to provide an assembled battery voltage measuring device capable of quickly grasping the state of the assembled battery by measuring the battery voltage.

In order to achieve the above object, the assembled battery voltage measuring device of the present invention is an assembled battery voltage measuring device that measures the voltage of the assembled battery in an assembled battery in which a plurality of battery units are connected in series, and is the assembled battery. Is a power supply source in the drive system, and the assembled battery voltage measuring device includes the first voltage measuring device for measuring the voltage of the battery unit of the first group and the battery unit of the second group. The first voltage measuring device includes a second voltage measuring device for measuring a voltage, and the first voltage measuring device has a smaller number of battery units for measuring a voltage than the second voltage measuring device. The voltage of the battery unit of the first group is measured by the measuring device in the first cycle, and the voltage of the battery unit of the second group is measured by the second voltage measuring device of the drive system. It is characterized in that it is performed by switching to the first cycle or the second cycle longer than the first cycle based on the state of.

Further, preferably, when the first voltage measuring device executes a predetermined process other than the voltage measurement together with the voltage measurement, and the second voltage measuring device switches to the first cycle. It is preferable to execute the predetermined process when the predetermined process is stopped and the second cycle is switched to.
Moreover, it is preferable that the predetermined process is at least one of the failure diagnosis process, the voltage equalization process, and the data storage process of the battery unit.

According to the assembled battery voltage measuring device of the present invention, since the number of battery units of the first group in which the first voltage measuring device measures the voltage is relatively small, the first voltage measuring device suppresses the measurement processing capacity. Even if it is, the voltage of the battery unit of the first group can be measured and processed at a relatively high speed in the first cycle. Since the battery units in the assembled battery are connected in series, the current flowing through all the battery units is the same, and by measuring the voltage of some of the battery units in the assembled battery at high speed, the entire assembled battery can be measured. It is possible to quickly grasp the battery status.

On the other hand, the second voltage measuring device switches the voltage measuring cycle between the first cycle and the second cycle based on the state of the drive system. When the voltage is measured in the second cycle longer than the first cycle , even if the second voltage measuring device suppresses the measurement processing capacity, the battery unit of the second group has a relatively large number. The voltage can be measured. Therefore, even if the number of battery units belonging to the second group is large, the voltage measurement processing of the battery unit is possible even if the second voltage measuring device suppresses the measurement processing capacity, and the second voltage measuring device can be used. The cost can be suppressed by reducing the number of. Further, when the voltage is measured in the first cycle, the voltage of the battery units of the second group can be measured quickly.

It is a schematic block diagram of the assembled battery voltage measuring apparatus of embodiment of this invention. It is a flowchart which shows the determination procedure of the various processing executed in the 1st voltage measuring apparatus which concerns on this embodiment. It is a flowchart which shows the determination procedure of various processing to execute in the 2nd voltage measuring apparatus which concerns on this embodiment. It is explanatory drawing which shows an example of the voltage measurement timing of each voltage measuring apparatus in this embodiment.

Hereinafter, an embodiment of an assembled battery voltage measuring device that embodies the present invention will be described.
FIG. 1 is a schematic configuration diagram of an assembled battery voltage measuring device 1 according to an embodiment of the present invention.
As shown in FIG. 1, the assembled battery voltage measuring device 1 of the present embodiment is provided in the assembled battery 3 that supplies electric power to the high voltage load 2, and is a device that monitors the state of the assembled battery 3.
The assembled battery voltage measuring device 1 of the present embodiment is mounted on a vehicle such as an electric vehicle or a plug-in hybrid vehicle. The high-voltage load 2 is an electric traveling drive motor or inverter of the vehicle, and the assembled battery 3 is an in-vehicle traveling driving battery that supplies electric power to the traveling drive motor.

The assembled battery 3 in the present embodiment is configured by connecting a plurality of battery cells 4a and 4b (battery units) such as a lithium ion battery in series. The circuit connecting the assembled battery 3 and the high voltage load 2 is provided with a switch 5 whose opening and closing is controlled by a control device 13 for a battery management system or a control unit (not shown), and connects the high voltage to the high voltage load.
Further, the supply of electric power from the assembled battery 3 to the high voltage load 2 is controlled by the control unit of the high voltage load 2 (not shown) based on the operation of the accelerator switch or the like of the vehicle.
The assembled battery voltage measuring device 1 includes two types of voltage measuring devices (first voltage measuring device 10 and second voltage measuring device 11) and a control device for a voltage management system that controls these voltage measuring devices 10 and 11. 13 and. The first voltage measuring device 10, the second voltage measuring device 11, and the control device 13 for the voltage management system are all input / output devices, storage devices (ROM, RAM, non-volatile RAM, etc.), and a central processing unit (CPU). ) Etc. are included in the control device. At least one first voltage measuring device 10 is provided, and the voltage of a part (for example, two) of the battery cells 4a and 4b among the plurality of battery cells 4a and 4b can be individually measured. The second voltage measuring device 11 is provided one by one for a plurality (for example, five) of battery cells 4b other than the battery cells 4a measured by the first voltage measuring device 10. The second voltage measuring device 11 can individually measure the voltage of the plurality of battery cells 4b in charge of each.

In the first voltage measuring device 10 and the second voltage measuring device 11, it is possible to make the timing of measuring the voltage of the plurality of battery cells 4a and 4b in charge the same. However, since the measurement results of the measured voltages are sequentially processed for each battery cell in the first voltage measuring device 10 and the second voltage measuring device 11, the larger the number of the battery cells 4a and 4b in charge, the more from the start of measurement. It takes time to complete the measurement process.

Further, the first voltage measuring device 10 has an equalization processing function for equalizing the voltage of the battery cell 4a in charge of voltage measurement. In the equalization process, the battery cell 4a having a high voltage among the battery cells 4a in charge is discharged by a resistor, or the battery cell 4a having a high voltage is charged to the battery cell 4a having a low voltage, and the voltage of the battery cell 4a is charged. Is the process of equalizing. Similar to the first voltage measuring device 10, the second voltage measuring device 11 also has an equalization processing function for equalizing the voltage of the battery cell 4b in charge of voltage measurement.

Further, the first voltage measuring device 10 and the second voltage measuring device 11 have a failure diagnosis processing function of the battery cells 4a and 4b in charge. The failure diagnosis process is performed by determining, for example, whether or not the voltage of the battery cells 4a and 4b is out of the predetermined range and whether or not the amount of fluctuation of the voltage is out of the predetermined range, and the corresponding battery cells 4a and 4b are performed. To identify.
Further, the first voltage measuring device 10 and the second voltage measuring device 11 have a data storage function. The data storage function stores various information such as the measured voltages of the battery cells 4a and 4b, failure information, and equalization processing execution information.

The voltage management system control device 13 inputs voltage information, failure information, and the like of the battery cells 4a and 4b measured by the first voltage measuring device 10 and the second voltage measuring device 11, and inputs the voltage information, failure information, and the like of the entire assembled battery 3. Monitor the status.
Further, the voltage management system control device 13 outputs a voltage measurement timing signal that defines the voltage measurement timing to all the first voltage measurement devices 10 and the second voltage measurement device 11. The voltage measurement timing signal may be a pulse signal output in a predetermined high-speed cycle ta (first cycle: for example, several tens of msec).

Next, the processing contents of the first voltage measuring device 10 and the second voltage measuring device 11 will be described.
FIG. 2 is a flowchart showing a determination procedure of various processes executed by the first voltage measuring device 10 according to the present embodiment.
The control shown in FIG. 2 is repeatedly executed in the first voltage measuring device 10 at predetermined time (for example, high-speed cycle ta) when the power is turned on.

First, in step S10, the voltage of each battery cell 4a is measured with a high-speed cycle ta. In this step, the voltage of each battery cell 4a is measured in accordance with the voltage measurement timing signal output from the voltage management system control device 13 in the high-speed cycle ta. Then, the process proceeds to step S20.
In step S20, a necessary process (predetermined process) to be executed in the first voltage measuring device 10 other than the voltage measurement is determined. Predetermined processes other than this voltage measurement are, for example, the above-mentioned failure diagnosis process, voltage equalization process, and data storage process. For example, when it is determined that the failure diagnosis process is always executed every high-speed cycle ta, and the voltage of any of the battery cells 4a in charge of the first voltage measuring device 10 is different from that of the other battery cells 4a by a predetermined value or more. To determine to execute the voltage equalization process. In addition, it is determined to execute the data storage process every predetermined period or when various data such as voltage changes by a predetermined value or more. The necessary processing to be executed other than the voltage measurement may be a diagnosis or processing for the battery cell 4a other than the failure diagnosis processing and the voltage equalization processing, and a plurality of these may be combined. Then, the process proceeds to step S30.

In step S30, the process determined in step S20 is executed. Then, this routine is returned.
FIG. 3 is a flowchart showing a determination procedure of various processes executed by the second voltage measuring device 11 in the assembled battery voltage measuring device of the present embodiment.
The control shown in FIG. 3 is repeatedly executed in the second voltage measuring device 11 at predetermined time (for example, high-speed cycle ta) when the power is turned on.

First, in step S100, the measurement cycle is determined based on the state of the traveling drive system (drive system) of the vehicle using the electric power of the assembled battery 3. Information on the operating state of the traveling drive system is input from a control device of the traveling drive system (not shown) via the voltage management system control device 13. The measurement cycle may be determined by, for example, any or a combination of a plurality of the following determination conditions (1) to (4). When a plurality of (1) to (4) are combined, it may be determined that the high-speed cycle is satisfied when any one of them satisfies the condition of the high-speed cycle.
(1) Operation mode of the traveling drive system In a hybrid vehicle, a mode in which the input / output power of the assembled battery 3 may be relatively large, such as an EV mode, a high power mode, and an eco mode, is determined to be a high-speed cycle. In the normal mode other than the above, it is determined that the low speed cycle 2 ta (second cycle) is twice the high speed cycle ta. The EV mode is a mode in which the hybrid vehicle is driven by only the traveling drive motor without operating the engine. The high power mode is a mode in which the output of the driving drive motor is made larger than the normal mode with respect to the accelerator operation amount, and the eco mode is a mode in which the regenerative power generation amount by the driving drive motor is made larger than the normal mode. be.
(2) Input / output judgment When the input / output power to the assembled battery 3 is equal to or higher than a predetermined value set appropriately, such as when the torque requirement, the power requirement, and the operation amount of the accelerator or the brake of the traveling drive system are large, the speed is high. Judged as a cycle. Under the condition that the input / output power to the assembled battery 3 is less than a predetermined value, it is determined that the low speed cycle is 2 ta.
(3) Speed of the traveling drive system When the speed of the traveling drive system (vehicle traveling speed) is equal to or higher than a predetermined value set appropriately, it is determined to be a high-speed cycle ta. If the speed of the traveling drive system is less than a predetermined value, it is determined that the low speed period is 2 ta.
(4) State of battery cell For example, in the battery cell 4b in charge, if there is even one battery cell 4b whose temperature is in a region close to the upper limit value or the lower limit value of the usage range, it is determined to be a high-speed cycle ta and the temperature is determined. If there is no battery cell 4b in a region close to the upper limit value or the lower limit value of the usage range, it is determined that the low speed cycle is 2 ta.

Alternatively, if there is at least one battery cell 4b in the battery cell 4b in charge whose voltage is in a region close to the upper limit value or the lower limit value of the usage range, it is determined to be a high-speed cycle ta, and the voltage is the upper limit value of the usage range. Alternatively, when there is no battery cell 4b in the region close to the lower limit value, it is determined that the low speed cycle is 2ta.
Then, the process proceeds to step S110.

In step S110, it is determined whether or not the measurement cycle determined in step S100 is the high-speed cycle ta. If the high-speed cycle ta, the process proceeds to step S120. If the high-speed cycle is not ta, the process proceeds to step S130.
In step S120, the high-speed periodic voltage measurement main operation is performed. The high-speed periodic voltage measurement main operation measures the voltage of each battery cell 4b in charge with a high-speed periodic ta without executing processing other than voltage measurement such as failure diagnosis processing and voltage equalization processing. Then, this routine is returned.

In step S130, the voltage of each battery cell 4b is measured in a low speed cycle of 2 ta. In this step, the voltage of the battery cell 4b may be measured in accordance with the voltage measurement timing signal at a rate of once every two times of the voltage measurement timing signal. Then, the process proceeds to step S140.
In step S140, the second voltage measuring device 11 determines the necessary processing to be executed other than the voltage measurement. The necessary processing is, for example, a failure diagnosis processing and a voltage equalization processing, as in the necessary processing determined in step S20. Then, the process proceeds to step S150.

In step S150, the process determined in step S130 is executed. Then, this routine is returned.
FIG. 4 is an explanatory diagram showing an example of voltage measurement timings of the voltage measuring devices 10 and 11 according to the present embodiment. The downward arrows in the figure indicate the timing of measuring the voltage of the battery cells 4a and 4b, respectively.

By determining and controlling as shown in FIGS. 2 and 3, the first voltage measuring device 10 and the second voltage measuring device 11 may have different voltage measurement cycles.
For example, FIG. 4 shows the voltage measurement timing when the low-speed cycle 2ta, the high-speed cycle ta, and the low-speed cycle 2ta are switched in this order every 4ta based on the state of the traveling drive system.

The first voltage measuring device 10 always measures the voltage of the battery cell 4a for each high-speed cycle ta regardless of whether the low-speed cycle or the high-speed cycle is determined from the state of the traveling drive system. It should be noted that the processing other than the voltage measurement can be executed as needed regardless of whether the low-speed cycle determination or the high-speed cycle determination is determined.
The second voltage measuring device 11 measures the voltage of the battery cell 4b every 2 ta of the low speed cycle when the low speed cycle is determined from the state of the traveling drive system. When the low-speed cycle is determined, processing other than voltage measurement can be executed as needed. On the other hand, when the high-speed cycle is determined from the state of the traveling drive system, the voltage of the battery cell 4b is measured for each high-speed cycle ta. At this time, no processing other than voltage measurement is executed.

As described above, in the assembled battery voltage measuring device 1 of the present embodiment, the plurality of battery cells 4a and 4b connected in series are the batteries of the first group in which the first voltage measuring device 10 is in charge of voltage measurement. It is divided into a cell 4a and a second group of battery cells 4b in which the second voltage measuring device 11 is in charge of voltage measurement. In the present embodiment, one first group, that is, one first voltage measuring device 10, is provided, and a plurality of second groups, that is, a plurality of second voltage measuring devices 11 are provided.

Since the number of battery cells 4a in the first group in which the first voltage measuring device 10 measures the voltage is relatively small, for example, two, the first voltage measuring device 10 suppresses the measurement processing capacity. Even if there is, the voltage of the battery cells 4a of the first group can be measured with a high-speed cycle ta.
Here, since the battery cells 4a and 4b in the assembled battery 3 are connected in series, the currents flowing through all the battery cells 4a and 4b are the same, and the voltage of some of the battery cells 4a in the assembled battery 3 is the same. By high-speed measurement, even if the voltage of the battery cells 4b of the second group is measured in a low-speed cycle of 2ta, the state of the entire assembled battery 3 can be roughly grasped quickly. .. Therefore, it is possible to perform various controls of the traveling drive system based on the three states of the assembled battery.

Further, since the second voltage measuring device 11 can perform voltage measurement in a low speed cycle of 2 ta, which is longer than the high speed cycle ta, even if the second voltage measuring device 11 suppresses the measurement processing capacity, the second voltage measuring device 11. It is possible to measure the voltage of a relatively large number of battery cells 4b in the group. Therefore, even if the total number of battery cells 4b belonging to the second group is large, the number of the second voltage measuring devices 11 is reduced while the measurement processing capacity of the second voltage measuring device 11 is suppressed to suppress the cost. can do.

The second voltage measuring device 11 switches the voltage measuring cycle between the high-speed cycle ta and the low-speed cycle 2 ta based on the state of the traveling drive system. The states of the traveling drive system include, for example, the operation mode of the traveling drive system, the input / output determination (input / output power to the assembled battery 3), the speed of the traveling drive system (vehicle traveling speed), and the states of the battery cells 4a and 4b (voltage). , Temperature) is used. For example, in the case of a mode such as EV mode, high power mode, and eco mode in which the input / output power of the assembled battery 3 may be large, when the input / output power to the assembled battery 3 is equal to or more than a predetermined value, the traveling drive system When the speed (vehicle running speed) of is equal to or higher than a predetermined value, the state of the assembled battery 3 can be quickly grasped, such as when the temperature or voltage of the battery cells 4a and 4b is in a region close to the upper limit value or the lower limit value of the usage range. When it is necessary to set the voltage measurement cycle of the battery cells 4b of the second group to the high-speed cycle ta, the voltages of all the battery cells 4a and 4b can be measured with the high-speed cycle ta. As a result, the traveling drive system can be appropriately controlled based on the voltages of all the battery cells 4a and 4b measured in the high-speed cycle ta. When the voltage measurement cycle of the battery cells 4b of the second group is set to the high-speed cycle ta, the second voltage measuring device 11 stops processing other than voltage measurement such as failure diagnosis processing and voltage equalization processing. Therefore, even if the number of battery cells 4b in charge is large, it is possible to measure the high-speed period ta of the voltage.

Although the description of the embodiment is completed above, the aspect of the present invention is not limited to the above embodiment. For example, in the present embodiment, the measurement cycle determination in step S100 of FIG. 3 is performed by the second voltage measuring device 11, but may be performed by the voltage management system control device 13. In this case, the voltage management system control device 13 may output the determination information to the second voltage measuring device 11, and the second voltage measuring device 11 may perform the processing after step S110.

Further, in the present embodiment, the first voltage measuring device 10 is one and a plurality of second voltage measuring devices 11 are provided, but two or more first voltage measuring devices 10 may be provided. .. Further, the number of battery cells 4a and 4b in charge of the first voltage measuring device 10 and the second voltage measuring device 11 is the processing capacity of each of the first voltage measuring device 10 and the second voltage measuring device 11. It may be set appropriately according to.

Further, in the above embodiment, the present invention is applied to an assembled battery configured by connecting a plurality of battery cells in series, but a plurality of battery units composed of a plurality of battery cells are connected in series. The present invention may be applied to an assembled battery configured by connecting. In this case, the first voltage measuring device 10 and the second voltage measuring device 11 measure the voltage of each battery unit, and by applying the present invention, the first voltage measuring device 10 and the second voltage measuring device 10 and the second voltage measurement. While the number of devices 11 is suppressed, the voltage of the battery unit can be measured at high speed to quickly grasp the state of the assembled battery.

Further, in the present embodiment, the present invention is applied to a traveling drive battery that is a power supply source of the vehicle driving system, but an in-vehicle battery other than the traveling drive battery or an in-vehicle battery other than the in-vehicle battery is applied. The present invention can also be widely applied to the above.

1 set battery voltage measuring device 3 sets battery 4a, 4b Battery cell (battery unit)
10 First voltage measuring device 11 Second voltage measuring device

Claims (3)

An assembled battery voltage measuring device that measures the voltage of the battery unit in an assembled battery in which a plurality of battery units are connected in series.
The assembled battery is a power supply source in the drive system.
The assembled battery voltage measuring device is
A first voltage measuring device for measuring the voltage of the battery unit of the first group, respectively, and
A second voltage measuring device for measuring the voltage of the battery unit of the second group, respectively, is provided.
The first voltage measuring device has a smaller number of battery units for measuring voltage than the second voltage measuring device.
The voltage of the battery unit of the first group is measured by the first voltage measuring device in the first cycle.
The measurement of the voltage of the battery unit of the second group by the second voltage measuring device is a second cycle longer than the first cycle or the first cycle based on the state of the drive system. An assembled battery voltage measuring device characterized in that it is performed by switching to. The first voltage measuring device executes a predetermined process other than the voltage measurement together with the voltage measurement.
The second voltage measuring device is characterized in that the predetermined process is stopped when the first cycle is switched to, and the predetermined process is executed when the second cycle is switched. Item 1. The assembled battery voltage measuring device according to item 1. The assembled battery voltage measuring device according to claim 2 , wherein the predetermined process is at least one of a failure diagnosis process, a voltage equalization process, and a data storage process of the battery unit.

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