WO2022249702A1 - Monitoring device and battery apparatus comprising same - Google Patents

Abstract

A battery apparatus (100) comprises a monitoring unit (10) and a control unit (30). The monitoring unit comprises a level shifter (12), an AD conversion unit (13), and a reference voltage circuit (16). The level shifter is provided with a plurality of range setting units (122, 123) which are each for varying an acquisition range of a closed-circuit voltage for a plurality of electrically-connected battery cells (220). The AD conversion unit converts, into a digital signal, the closed-circuit voltage outputted from the level shifter within the acquisition ranges set by the range setting units. The reference voltage circuit outputs a reference voltage to the level shifter. The control unit (30) comprises an arithmetic unit (33). On the basis of a reference voltage outputted by the reference signal unit and a plurality of reference voltages that have been converted into digital signals by the AD conversion unit within the plurality of acquisition ranges set by the respective range setting units, the arithmetic unit determines which of the range setting units has an abnormality occurring therein.

Description

Monitoring device and battery device including same Cross-reference to related applications

This application is based on Patent Application No. 2021-90409 filed in Japan on May 28, 2021, and the content of the underlying application is incorporated by reference in its entirety.

The disclosure described in this specification relates to a monitoring device and a battery device including the same.

Patent Document 1 discloses a capacity adjustment device that equalizes the SOC of a plurality of lithium secondary batteries.

JP 2010-141957 A

The closed-circuit voltage of lithium secondary batteries is used to equalize the SOCs of multiple lithium secondary batteries. Therefore, it is required to improve the detection accuracy of the closed circuit voltage. In order to improve the detection accuracy of the closed circuit voltage, the number of components may increase. It is required to diagnose in which one of the plurality of components (range setting section) an abnormality has occurred.

An object of the present disclosure is to provide a monitoring device capable of diagnosing a plurality of range setting units for abnormality, and a battery device including the monitoring device.

A monitoring device according to one aspect of the present disclosure includes a level shifter including a plurality of range setting units for changing acquisition ranges of closed circuit voltages of a plurality of electrically connected battery cells;
an AD converter that converts the closed-circuit voltage output from the level shifter into a digital signal within the acquisition range set by the level shifter;
and a reference signal unit for outputting a reference signal for diagnosing the state of each of the plurality of range setting units to the level shifter.

A battery device according to an aspect of the present disclosure includes a level shifter including a plurality of range setting units for changing acquisition ranges of closed circuit voltages of a plurality of electrically connected battery cells;
an AD conversion unit that converts the closed circuit voltage output from the level shifter into a digital signal within the acquisition range set by the range setting unit;
a reference signal unit for outputting to the level shifter a reference signal for diagnosing the state of each of the plurality of range setting units;
A plurality of and a judgment unit for judging which of the range setting units has an abnormality.

According to this, it is possible to diagnose an abnormality in a plurality of range setting units.

It should be noted that the reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope in any way.

1 is a block diagram showing a battery device and an assembled battery; FIG. It is a graph chart which shows the characteristic of SOC and OCV. 4 is a circuit diagram showing a level shifter; FIG. 4 is a flowchart for explaining diagnostic processing; 9 is a flowchart for explaining a modified example of diagnostic processing; FIG. 10 is a circuit diagram showing a modification of the level shifter; 4 is a timing chart for explaining voltage detection; 4 is a timing chart for explaining voltage detection; 4 is a flowchart for explaining voltage detection processing; 4 is a flowchart for explaining voltage detection processing; 4 is a timing chart for explaining ground fault detection; 4 is a timing chart for explaining power fault detection; 5 is a flowchart for explaining short-circuit determination processing; 4 is a timing chart for explaining ground fault detection; 4 is a timing chart for explaining power fault detection; 4 is a timing chart for explaining ground fault detection; 4 is a timing chart for explaining ground fault detection; 4 is a timing chart for explaining power fault detection; 4 is a timing chart for explaining ground fault detection; 4 is a timing chart for explaining power fault detection;

A plurality of modes for carrying out the present disclosure will be described below with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding form, and overlapping explanations may be omitted. When only a part of the configuration is described in each form, the previously described other forms can be applied to other parts of the configuration.

It is possible to combine parts that are specifically stated to be combinable in each embodiment. In addition, if there is no particular problem with the combination, it is possible to partially combine the embodiments, the embodiments and the modified examples, and the modified examples even if it is not explicitly stated that the combination is possible. be.

<First Embodiment>
A first embodiment will be described with reference to FIGS. 1 to 6. FIG.

A battery device 100 and an assembled battery 200 are shown in FIG. The battery device 100 and the assembled battery 200 are mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle. The electric vehicles include passenger cars, buses, construction vehicles, agricultural machinery vehicles, and the like.

The battery device 100 monitors and controls the state of the assembled battery 200 . The assembled battery 200 supplies power to various in-vehicle devices such as an electric motor that provides propulsion to the electric vehicle.

<Battery pack>
The assembled battery 200 has a plurality of battery stacks 210 . Each of the plurality of battery stacks 210 has a plurality of battery cells 220 electrically connected in series. As the battery cell 220, a secondary battery such as a lithium-ion secondary battery, a nickel-hydrogen secondary battery, or an organic radical battery can be employed. The output voltage of the battery cells 220 connected in series is the output voltage of the battery stack 210 . In FIG. 1, a plurality of battery cells 220 included in one battery stack 210 are shown surrounded by dashed lines.

The plurality of battery stacks 210 are electrically connected in series or in parallel. In this embodiment, a plurality of battery stacks 210 are electrically connected in series. The output voltage of the assembled battery 200 is the sum of the output voltages of the plurality of battery stacks 210 connected in series. Power supply power dependent on this output voltage is supplied to various vehicle-mounted devices.

A physical quantity sensor 230 that detects the physical quantity of the battery cell 220 is provided in each of the plurality of battery stacks 210 . Physical quantities detected by the physical quantity sensor 230 include, for example, the temperature and current of the battery cell 220 .

The physical quantity detected by the physical quantity sensor 230 is used for estimating the SOC of each of the battery cells 220, the battery stack 210, and the assembled battery 200. SOC is an abbreviation for state of charge.

The SOC is reduced by supplying the above-mentioned power supply power to various on-vehicle devices. Also, the battery cell 220 self-discharges. Therefore, the SOC decreases even when the power supply is not supplied.

This reduction in SOC is improved by supplying charging power to the assembled battery 200 from a charging device such as a desk lamp provided outside the vehicle, for example. The supply of charging power from this charging device to the assembled battery 200 is controlled by the battery device 100 . The battery device 100 controls charging of the assembled battery 200 while transmitting/receiving a CPLT signal to/from a charging device via wiring (not shown).

It should be noted that the quality and environment of the plurality of battery cells 220 are not uniform. Therefore, the SOCs of the plurality of battery cells 220 vary. This variation is improved by an equalization process, which will be described later.

<OCV, CCV, SOC>
The battery cell 220 has internal resistance. Therefore, there is a difference between the actual cell voltage corresponding to the SOC of the battery cell 220 and the cell voltage detected by the monitoring unit 10 by this internal resistance and the voltage drop corresponding to the current flowing through the battery cell 220 .

In the following, the actual cell voltage corresponding to the SOC of the battery cell 220 is indicated as open circuit voltage OCV as necessary. A cell voltage detected by the monitoring unit 10 is indicated as a closed circuit voltage CCV. Assume that the internal resistance R is the resistance in the battery cell 220 and the actual current I is the current that actually flows through the battery cell 220 . OCV is an abbreviation for Open Circuit Voltage. CCV stands for Closed Circuit Voltage.

The relationship between the closed circuit voltage CCV and the open circuit voltage OCV is expressed as CCV=OCV±I×R. When the battery cell 220 is discharged, CCV=OCV-I×R. When charging the battery cell 220, CCV=OCV+I×R.

<Characteristics of SOC and OCV>
The battery cell 220 has SOC and OCV characteristics. FIG. 2 shows SOC and OCV characteristic data when the battery cell 220 is a lithium ion secondary battery.

As shown in FIG. 2, in the overdischarge region where the SOC is close to 0%, the rate of change of OCV with respect to SOC is high. In the overcharge region where the SOC is close to 100%, the rate of change of OCV with respect to SOC is high.

On the other hand, in the charge/discharge region between the overdischarge region and the overcharge region, the change rate of OCV with respect to SOC is low. Battery cell 220 is mainly used in this charge/discharge region. In FIG. 2, as an example, the values of SOC and OCV between the overdischarge region and the charge/discharge region are expressed as SOC1 and OCV1. SOC and OCV values between the charge/discharge region and the overcharge region are denoted as SOC2 and OCV2.

The characteristic data shown in Fig. 2 depend on temperature. Therefore, the rate of change of OCV with respect to SOC changes depending on the temperature. Along with this, the values of SOC1, SOC2, OCV1 and OCV2 also change.

<Battery device>
The battery device 100 has a monitoring section 10 and a control section 30 . The battery device 100 has the same number of monitoring units 10 as the battery stacks 210 . The plurality of monitoring units 10 detect battery information related to the state of each of the plurality of battery stacks 210 . Note that the battery device 100 may have more monitoring units 10 than the battery stacks 210 . In this case, one battery stack 210 is provided with a plurality of monitoring units 10 . This monitoring unit 10 monitors some of the plurality of battery cells 220 included in one battery stack 210 .

The control unit 30 diagnoses a plurality of monitoring units 10. Also, the control unit 30 acquires battery information detected by the plurality of monitoring units 10 . The control unit 30 acquires vehicle information input from various ECUs and various sensors (not shown). When a charging device is connected to the electric vehicle, the control unit 30 acquires charging information input from the charging device. The input to the control unit 30 of the vehicle information and charging information, and the output of the processing results of the control unit 30 to various ECUs, charging equipment, etc. are indicated by white arrows in FIG.

The control unit 30 determines the state of the assembled battery 200 based on the acquired information. At the same time, the control unit 30 executes processing for the assembled battery 200 . The processing for the assembled battery 200 includes, for example, charging and discharging of the assembled battery 200, equalization processing for equalizing the SOCs of the plurality of battery cells 220 included in the assembled battery 200, and the like.

<Monitoring part>
Each of the plurality of monitoring units 10 is individually provided for each of the plurality of battery stacks 210 . One monitoring unit 10 detects the inter-terminal voltage (closed-circuit voltage) between the positive and negative electrodes of each of the plurality of battery cells 220 included in one battery stack 210 . Also, the monitoring unit 10 acquires the physical quantity detected by the physical quantity sensor 230 . The monitoring unit 10 executes processing based on instruction signals input from the control unit 30 .

As shown in FIG. 1, the monitoring section 10 has a multiplexer 11, a level shifter 12, an AD conversion section 13, a monitoring control section 14, a monitoring communication section 15, and a reference voltage circuit 16. In the drawing, the multiplexer 11 is written as MUX. The level shifter 12 is written as LS. The AD converter 13 is written as AD. The monitor control unit 14 is written as MCU. The monitoring communication unit 15 is written as MCS. The reference voltage circuit 16 is written as VRC.

The multiplexer 11 is connected to the positive and negative electrodes of each of the plurality of battery cells 220 included in one battery stack 210 . As a result, the multiplexer 11 receives the closed circuit voltages of the plurality of battery cells 220 .

Also, the multiplexer 11 is connected to the physical quantity sensor 230 . Thereby, the physical quantity is input to the multiplexer 11 .

The multiplexer 11 sequentially selects and detects a plurality of input closed circuit voltages. The multiplexer 11 sequentially outputs the detected closed circuit voltages to the level shifter 12 . The multiplexer 11 also sequentially selects and detects a plurality of input physical quantities. The multiplexer 11 also sequentially outputs the detected physical quantities to the level shifter 12 .

As shown in FIG. 3, the level shifter 12 has an operational amplifier 121, a plurality of clamp circuits 122, and a plurality of feedback circuits 123. In the drawing, the clamp circuit 122 is denoted as CC. The feedback circuit 123 is denoted by FC.

The operational amplifier 121 has two input terminals and two output terminals. Two input terminals of operational amplifier 121 are connected to multiplexer 11 . Two output terminals of the operational amplifier 121 are connected to the AD converter 13 . A plurality of clamp circuits 122 are connected to two input terminals of the operational amplifier 121 . A plurality of feedback circuits 123 are provided between two input terminals and two output terminals of the operational amplifier 121, respectively. These multiple feedback circuits 123 are connected in parallel.

Each of the plurality of clamp circuits 122 includes at least one switch. This switch is controlled by the monitoring control unit 14 to be in an energized state and an interrupted state. The input range of the operational amplifier 121 is thereby controlled. The offset of operational amplifier 121 is controlled. Note that when all the switches included in each of the plurality of clamp circuits 122 are in the off state, the input range of the operational amplifier 121 is between the upper limit value and the lower limit value of the power supply voltage. The clamp circuit 122 corresponds to the offset adjustment section.

Each of the plurality of feedback circuits 123 includes at least one series circuit. The series circuit has a switch and a capacitor connected in series. This switch is controlled by the monitoring control unit 14 to be in an energized state and an interrupted state. This changes the number of capacitors connected between the input terminal and the output terminal of the operational amplifier 121 . A capacitance between the input terminal and the output terminal of the operational amplifier 121 changes. Also, the resistance between the input terminal and the output terminal of the operational amplifier 121 changes. As a result, the gain of the operational amplifier 121 is controlled. Note that the capacitance of the capacitors included in the plurality of feedback circuits 123 may be the same or different. The feedback circuit 123 corresponds to the gain adjustment section.

The AD conversion unit 13 receives from the level shifter 12 an analog signal of a closed circuit voltage and a physical quantity whose gain and offset have been adjusted. By adjusting the gain and offset of the level shifter 12, the voltage range of the analog signal converted from analog to digital by the AD converter 13 is controlled. The voltage range of the closed circuit voltage and the physical quantity that are analog-to-digital converted by the AD converter 13 are controlled. As a result, the acquisition range of the closed circuit voltage and the physical quantity is controlled. Note that it is not necessary to particularly control the acquisition range of the physical quantity.

The AD converter 13 intermittently samples continuous analog signals. Then, the AD converter 13 quantizes the sampled values and converts them into discrete digital signals. Due to such conversion, there is an error (quantization error) between the analog signal and the digital signal.

This quantization error becomes smaller as the number of quantization bits of the AD converter 13 increases. However, the number of quantization bits is fixed. Therefore, for example, when the acquisition range of the closed circuit voltage is 0.0 V to 5.0 V, the resolution of the AD converter 13 is the value obtained by dividing this 0.0 V to 5.0 V by the number of quantization bits.

On the other hand, for example, when the acquisition range of the closed circuit voltage is 3.0 V to 3.5 V, which is 1/10, the resolution of the AD conversion unit 13 is 3.0 V to 3.5 V with the number of quantization bits. becomes the divided value. In this case, the resolution of the AD converter 13 is increased by about ten times. By limiting the acquisition range in this way, the detection accuracy of the closed circuit voltage is improved.

The monitoring control unit 14 has a processor and a non-transitional physical storage medium that non-temporarily stores programs and data readable by this processor. A digital signal input from the AD conversion unit 13 and an instruction signal input from the control unit 30 are stored in this non-transitional substantive storage medium. The processor of the monitor controller 14 controls the multiplexer 11, the level shifter 12, the AD converter 13, and the reference voltage circuit 16 based on the instruction signal.

Note that the AD conversion unit 13 and the monitoring control unit 14 may be connected via a digital filter. With such a configuration, the digital filter removes noise contained in the digital signal output from the AD converter 13 . The noise-removed digital signal is input to the monitor control unit 14 .

The instruction signal input from the control unit 30 to the monitoring control unit 14 includes the acquisition range of the closed circuit voltage of the battery cell 220 to be detected. The monitor control unit 14 controls the gain and offset of the level shifter 12 when the multiplexer 11 selects the closed circuit voltage to be detected. This controls the acquisition range of the closed circuit voltage.

The closed-circuit voltage of the digital signal and the physical quantity are input to the monitoring communication unit 15 . The monitor communication unit 15 outputs this digital signal to the control unit 30 . Also, an instruction signal is input to the monitoring communication unit 15 . This instruction signal is input to the monitor control unit 14 .

The reference voltage circuit 16 is connected to the multiplexer 11. A reference voltage circuit 16 generates a reference voltage. This reference voltage is input to the AD converter 13 via the level shifter 12 . Note that the reference voltage circuit 16 may be connected to the level shifter 12 instead of the multiplexer 11 . The reference voltage circuit 16 corresponds to the reference signal section. A reference voltage corresponds to a reference signal.

When the level shifter 12 is normal, the voltage input to the AD converter 13 via the level shifter 12 is expected to be the same as the reference voltage. When the level shifter 12 has an abnormality, it is assumed that the voltage input to the AD converter 13 via the level shifter 12 will be different from the reference voltage. Thus, the reference voltage is used for diagnosis of the level shifter 12. FIG.

<Control section>
As shown in FIG. 1 , the control unit 30 has a control communication unit 31 , a storage unit 32 and a calculation unit 33 . In the drawing, the control communication unit 31 is denoted as CCU. The storage unit 32 is written as MU. The calculation unit 33 is written as OP.

Various information is input to the control communication unit 31 . This information includes the closed circuit voltage and the physical quantity acquired by the monitoring unit 10 . In addition, this information includes vehicle information and charging information. The vehicle information includes the running state of the electric vehicle and the current time. The charging information includes charging power.

Note that vehicle information and charging information may be input to a communication unit (not shown). And when the control part 30 has RTC, the present time does not need to be contained in vehicle information. RTC is an abbreviation for real time clock.

The storage unit 32 is a non-transitional material storage medium that non-temporarily stores programs readable by computers and processors. The storage unit 32 has a volatile memory and a nonvolatile memory. Various information input to the control communication unit 31 and processing results of the calculation unit 33 are stored in the storage unit 32 .

In addition, the storage unit 32 stores in advance programs and reference values for the operation unit 33 to carry out operation processing. The reference values include, for example, the voltage level of the reference voltage, the temperature dependence of the SOC and OCV characteristic data of various secondary batteries, the equalization determination value for determining execution of the equalization process, and the manufacturing data of the plurality of battery cells 220. date, deterioration judgment value, and the like.

The computing unit 33 includes a processor. The calculation unit 33 stores various information input to the control communication unit 31 in the storage unit 32 . The calculation unit 33 executes various calculation processes based on information stored in the storage unit 32 . An electrical signal including the result of this arithmetic processing is output to the monitoring section 10 via the control communication section 31 . An electrical signal including the result of this arithmetic processing is output to various ECUs via the control communication unit 31 or a communication unit (not shown).

To give a specific example of the arithmetic processing, the arithmetic unit 33 estimates the SOC of the battery cell 220 based on the information stored in the storage unit 32 . The calculation unit 33 generates an instruction signal for instructing the operation of the monitoring unit 10 based on the estimated SOC and the information stored in the storage unit 32 .

The computing unit 33 causes the monitoring unit 10 to self-diagnose. The calculation unit 33 outputs an instruction signal including an instruction to execute this self-diagnosis to the monitoring unit 10 . Self-diagnosis of the monitoring unit 10 will be described later.

The calculation unit 33 determines the acquisition range of the closed circuit voltage of the battery cell 220 to be detected. The calculation unit 33 outputs an instruction signal including this acquisition range to the monitoring unit 10 . The calculation unit 33 determines the acquisition range of the closed circuit voltage based on the battery information related to the estimation of the SOC of the battery cell 220 to be detected.

If the storage unit 32 does not store the battery information for estimating the SOC, the calculation unit 33 sets the acquisition range of the closed circuit voltage to the possible range of the closed circuit voltage of the battery cell 220 . The above battery information includes, for example, the closed circuit voltage of the battery cell 220 detected in the past.

The calculation unit 33 determines execution of equalization processing for reducing variations in the SOCs of the plurality of battery cells 220 . The calculation unit 33 outputs an instruction signal including equalization processing for each of the plurality of battery stacks 210 to the monitoring unit 10 .

The computing unit 33 computes the difference between the maximum value and the minimum value of the closed circuit voltage input from the monitoring unit 10 . If this difference exceeds the equalization determination value, the calculation unit 33 decides to execute the equalization process. This equalization process may be performed, for example, only in the battery stack 210 in which at least one of the maximum value and the minimum value of the closed circuit voltage is detected. The equalization process may be performed on all battery stacks 210 .

Although not clearly shown in the drawing, the monitoring unit 10 has a plurality of switches that bridge a plurality of wires connecting the multiplexer 11 and the positive and negative electrodes of the plurality of battery cells 220, respectively. The monitoring control unit 14 selectively controls the plurality of switches to the energized state and the cut-off state based on the instruction signal input from the arithmetic unit 33 .

When the switches are controlled to be energized, the positive electrodes and the negative electrodes of the plurality of battery cells 220 are connected. As a result, among the plurality of electrically connected battery cells 220, the battery cell 220 with a relatively high SOC is discharged. Conversely, battery cells 220 with relatively low SOC are charged. As a result, the SOCs of the plurality of battery cells 220 are equalized.

<Self-diagnosis>
When the monitor control unit 14 of the monitor unit 10 receives the instruction signal including the self-diagnosis execution instruction, it causes the reference voltage circuit 16 to output the reference voltage to the multiplexer 11 . At the same time, the monitor control unit 14 causes the multiplexer 11 to output the reference voltage to the level shifter 12 .

Also, the monitor control unit 14 appropriately selects the plurality of clamp circuits 122 and the plurality of feedback circuits 123 included in the level shifter 12 . The acquisition range determined by the selected clamp circuit 122 and feedback circuit 123 and the reference voltage analog-to-digital converted by the AD converter 13 in this acquisition range are each input to the control unit 30 via the monitoring communication unit 15. be.

When the analog-to-digital converted reference voltage in a certain acquisition range and the voltage level of the reference voltage stored in the storage unit 32 are the same, the calculation unit 33 of the control unit 30 determines that the acquisition range can be used. judge. That is, the calculation unit 33 determines that the clamp circuit 122 and the feedback circuit 123 that define the acquisition range, and the components other than these in the monitoring unit 10 are normal. The calculation unit 33 corresponds to the determination unit.

Conversely, if the analog-to-digital converted reference voltage in a certain acquisition range is different from the reference voltage stored in the storage unit 32, the calculation unit 33 determines that the acquisition range is unusable. do. That is, the calculation unit 33 determines that at least one of the clamp circuit 122 and the feedback circuit 123 that define the acquisition range, or other constituent elements of the monitoring unit 10 is abnormal.

The monitor control unit 14 combines a plurality of clamp circuits 122 and a plurality of feedback circuits 123, and outputs the reference voltage analog-to-digital converted by the AD conversion unit 13 to the control unit 30 within a plurality of acquisition ranges determined thereby. The calculation unit 33 of the control unit 30 compares the analog-to-digital converted reference voltages in a plurality of acquisition ranges with the stored reference voltages. Based on the plurality of comparison results, the calculation unit 33 diagnoses which of the constituent elements included in the monitoring unit 10 has an abnormality.

The computing unit 33 diagnoses whether at least one of the clamp circuit 122 and the feedback circuit 123 is abnormal. The computing unit 33 diagnoses whether or not at least one of the clamp circuits 122 is abnormal. The computing unit 33 diagnoses whether or not at least one of the plurality of feedback circuits 123 is abnormal. The computing unit 33 diagnoses whether or not there is an abnormality in components other than the plurality of clamp circuits 122 and the plurality of feedback circuits 123 in the monitoring unit 10 .

Based on this diagnostic result, the calculation unit 33 determines whether or not the closed circuit voltage can be obtained. The calculation unit 33 determines whether or not to limit the acquisition range of the closed circuit voltage.

<Diagnostic processing>
Next, the diagnostic processing of the computing unit 33 will be described with reference to FIG. The computing unit 33 executes this diagnostic processing as an event task when the electric vehicle starts up. Note that the calculation unit 33 may execute this diagnostic processing as a cycle task. However, when the diagnostic process is executed as a cycle task, the diagnostic cycle is set longer than the closed circuit voltage acquisition cycle.

In step S10, the calculation unit 33 outputs a diagnosis signal to the monitoring unit 10 as an instruction signal including an instruction to execute self-diagnosis. After that, the calculation unit 33 proceeds to step S20.

Upon receiving the diagnostic signal, the monitoring unit 10 obtains a plurality of acquisition ranges determined by a combination of a plurality of clamp circuits 122 and a plurality of feedback circuits 123, and a plurality of reference voltages analog-to-digital converted in the plurality of acquisition ranges. , are output to the calculation unit 33 .

When proceeding to step S20, the calculation unit 33 stores the plurality of acquisition ranges and the plurality of reference voltages input from the monitoring unit 10 in the storage unit 32. Then, the calculation unit 33 diagnoses the state of the monitoring unit 10 based on the results of comparison between each of the plurality of input reference voltages and the reference voltages stored in the storage unit 32 and the plurality of acquisition ranges. As a result of the diagnosis, when it is determined that there is an abnormality in the monitoring unit 10, the calculation unit 33 proceeds to step S30. When determining that there is no abnormality in the monitoring unit 10, the calculation unit 33 proceeds to step S40.

When proceeding to step S30, the calculation unit 33 determines whether or not the level shifter 12 included in the monitoring unit 10 has an abnormality. More specifically, the computing unit 33 determines whether or not the plurality of clamp circuits 122 and the plurality of feedback circuits 123 included in the level shifter 12 are abnormal. If it is determined that at least one of these is abnormal, the calculation unit 33 proceeds to step S50. When determining that there is no abnormality in these, the calculation unit 33 proceeds to step S70. That is, if it is determined that there is an abnormality in the components other than the plurality of clamp circuits 122 and the plurality of feedback circuits 123 in the monitoring section 10, the calculation section 33 proceeds to step S70.

When proceeding to step S50, the calculation unit 33 determines whether or not there is a usable clamp circuit 122 among the plurality of clamp circuits 122. At the same time, the calculation unit 33 determines whether or not there is any one of the plurality of feedback circuits 123 that can be used.

Then, the calculation unit 33 determines whether or not the acquisition range can be determined using the available circuit elements. If it is determined that there is a usable acquisition range, the calculation unit 33 proceeds to step S60. If it is determined that there is no usable acquisition range, the calculation unit 33 proceeds to step S70.

When proceeding to step S60, the calculation unit 33 determines to set the acquisition range of the closed circuit voltage in the limited state because there is an abnormality in some of the plurality of clamp circuits 122 and the plurality of feedback circuits 123. Then, the calculation unit 33 terminates the diagnostic processing.

When proceeding to step S70, the calculation unit 33 outputs an electrical signal (voltage prohibition signal) including prohibition of calculation processing using the voltage detected by the battery device 100 to various ECUs. Various ECUs, upon receiving the voltage prohibition signal, determine whether the electric vehicle should be driven in a limited manner, in an evacuation mode, or stopped.

Going back in the flow, when it is determined in step S20 that there is no abnormality in the monitoring unit 10 and the process proceeds to step S40, the calculation unit 33 determines that there is no abnormality in the monitoring unit 10. Decide to set. Then, the calculation unit 33 terminates the diagnostic processing.

<Challenge>
As described above, the closed circuit voltage acquisition range is determined by selecting at least one from the plurality of clamp circuits 122 and at least one from the plurality of feedback circuits 123 . In order to finely set the acquisition range, the number of clamp circuits 122 and feedback circuits 123 increases. As a result, it may be difficult to diagnose which of the plurality of clamp circuits 122 that determine the acquisition range and the plurality of feedback circuits 123 (the plurality of range setting units) has an abnormality.

<Effect>
To solve this problem, the computing section 33 selects at least one from the plurality of clamp circuits 122 and selects at least one from the plurality of feedback circuits 123 . Then, the calculation unit 33 sets the acquisition range by combining the selected clamp circuit 122 and feedback circuit 123 . The calculation unit 33 sets a plurality of acquisition ranges by switching between these selections and combinations.

The calculation unit 33 then compares the reference voltages stored in the storage unit 32 with the reference voltages analog-to-digital converted by the AD conversion unit 13 in these acquisition ranges. As a result, it is determined which one of the plurality of clamp circuits 122 and the plurality of feedback circuits 123 (the plurality of range setting units) has an abnormality.

When an abnormality occurs in one of the plurality of clamp circuits 122 and the plurality of feedback circuits 123, the computing section 33 determines whether or not the usable acquisition range can be set. According to this, acquisition of the closed circuit voltage is likely to be continued. In addition, a decrease in detection accuracy of the closed circuit voltage is suppressed.

(First modification)
In this embodiment, the example in which the calculation unit 33 executes the diagnostic processing shown in FIG. 4 has been described. However, the calculation unit 33 may execute the diagnostic processing shown in FIG.

If it is determined in step S20 shown in FIG. 5 that there is an abnormality in the monitoring unit 10, the calculation unit 33 proceeds to step S110.

When proceeding to step S110, the calculation unit 33 determines whether or not both the clamp circuit 122 and the feedback circuit 123 are abnormal. If both the clamp circuit 122 and the feedback circuit 123 are abnormal, the operation section 33 proceeds to step S50. Steps S50 to S70 after step S50 have already been explained, so the explanation thereof will be omitted. If both the clamp circuit 122 and the feedback circuit 123 are normal, the operation section 33 proceeds to step S120.

When proceeding to step S120, the calculation unit 33 determines whether or not the clamp circuit 122 is abnormal. If there is an abnormality in the clamp circuit 122, the calculation section 33 proceeds to step S130. If the clamp circuit 122 does not malfunction, the calculation unit 33 proceeds to step S140.

An abnormality in the clamp circuit 122 is mainly a state in which a switch included in the clamp circuit 122 cannot be switched between an energized state and a cut-off state. If the switch is stuck in the energized state, the offset of the op amp 121 will be stuck. If the switch is stuck in the cut-off state, the offset adjustment of the operational amplifier 121 will be limited. If all the switches included in the plurality of clamp circuits 122 are stuck in the cut-off state, the offset of the operational amplifier 121 cannot be adjusted.

When proceeding to step S130, the calculation unit 33 determines whether or not the storage unit 32 stores the closed circuit voltage of the battery cell 220 to be detected. When the closed circuit voltage is stored, the calculation unit 33 determines whether the stored closed circuit voltage is included in the acquisition range of the closed circuit voltage that can be set by the plurality of clamp circuits 122 including the clamp circuit 122 in an abnormal state. determine whether

When the closed circuit voltage is included in this acquisition range, the calculation unit 33 determines that there is a limited range (limited range) of the available closed circuit voltage acquisition range. Then, the calculation unit 33 proceeds to step S150. When the closed circuit voltage is not included in this acquisition range, the calculation unit 33 determines that there is no usable limited range. Then, the calculation unit 33 proceeds to step S160. In the first place, if the storage unit 32 does not store the closed circuit voltage of the battery cell 220 to be detected, the operation unit 33 proceeds to step S160.

When proceeding to step S150, the calculation unit 33 determines to set the acquisition range of the closed circuit voltage in the restricted state in the same manner as in step S60. When proceeding to step S<b>160 , the calculation unit 33 determines not to use any of the plurality of clamp circuits 122 . The calculation unit 33 determines to detect the closed circuit voltage in the acquisition range (entire range) of the possible range of the closed circuit voltage. After step S150 or step S160, the calculation unit 33 terminates the diagnosis process.

If it is determined in step S120 that the clamp circuit 122 is not abnormal and the process proceeds to step S140, the calculation unit 33 determines whether the feedback circuit 123 is abnormal. , the computing unit 33 proceeds to step S170. If the feedback circuit 123 does not malfunction, the calculation unit 33 proceeds to step S190. That is, if there is an abnormality in the constituent elements other than the clamp circuit 122 and the feedback circuit 123 in the monitoring section 10, the calculation section 33 proceeds to step S190.

An abnormality in the feedback circuit 123 is mainly a state in which a switch included in the feedback circuit 123 cannot be switched between an energized state and a cut-off state. If the switch is stuck in the conducting state or the blocking state, the gain of the operational amplifier 121 is limited. If all the switches included in the plurality of feedback circuits 123 are stuck, the gain of the operational amplifier 121 cannot be adjusted.

When proceeding to step S170, the computing section 33 determines whether or not the feedback circuit 123 can determine the gain. If the gain can be determined, the calculation unit 33 determines that there is a usable acquisition range. Then, the calculation unit 33 proceeds to step S180. If the gain cannot be determined, the calculation unit 33 determines that there is no usable acquisition range. Then, the calculation unit 33 proceeds to step S190.

When proceeding to step S180, the calculation unit 33 determines to set the acquisition range of the closed circuit voltage in the restricted state in the same manner as in step S60. When proceeding to step S190, the calculation unit 33 outputs a voltage prohibition signal to various ECUs in the same manner as in step S70. After step S180 or step S190, the calculation unit 33 terminates the diagnosis process.

(Second modification)
In this embodiment, an example in which the monitoring unit 10 has one multiplexer 11 and one operational amplifier 121 is shown. However, the monitoring unit 10 may have multiple multiplexers 11 and multiple operational amplifiers 121 . For example, as shown in FIG. 6, the monitoring unit 10 may have two multiplexers 11 and two operational amplifiers 121 . A plurality of clamp circuits 122 and a plurality of feedback circuits 123 are connected to each of the two operational amplifiers 121 . Note that the monitoring unit 10 may have a plurality of operational amplifiers 121 and a single multiplexer 11 .

In this modified example, when the monitoring unit 10 receives the diagnostic signal, the acquisition range determined by the combination of the clamp circuit 122 and the feedback circuit 123 is the same for the two operational amplifiers 121 . The monitoring unit 10 outputs a plurality of acquisition ranges and two reference voltages analog-to-digital converted in the plurality of acquisition ranges to the calculation unit 33 .

The calculation unit 33 stores in the storage unit 32 a plurality of acquisition ranges input from the monitoring unit 10 and two reference voltages analog-to-digital converted in the plurality of acquisition ranges. Then, the calculation unit 33 compares the two reference voltages analog-to-digital converted in the plurality of acquisition ranges with the reference voltage stored in advance in the storage unit 32, and based on the plurality of acquisition ranges, the monitoring unit 10 Diagnose the condition.

When the clamp circuit 122 and the feedback circuit 123 connected to one of the two operational amplifiers 121 are normal, and the clamp circuit 122 and the feedback circuit 123 connected to the other are abnormal, the computing unit 33 prohibit the use of the other. Further, when the level shifter 12 has one operational amplifier 121 as in the present embodiment, an abnormality occurs in a part of a plurality of current paths formed between two input terminals and two output terminals of the operational amplifier 121. If it occurs, the use of that current path may be prohibited.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 7 to 10. FIG.

In the first embodiment, an example was shown in which the acquisition range of the closed circuit voltage is determined based on the closed circuit voltage stored in the storage unit 32 . In contrast, in the present embodiment, the acquisition range of the closed circuit voltage is determined based on the closed circuit voltage stored in the storage unit 32 and the amount of change in the closed circuit voltage.

<Acquisition of closed circuit voltage>
Due to the SOC and OCV characteristics of the battery cell 220 shown in FIG. 2, when the SOC drops due to discharge, the OCV also drops. Accordingly, the closed circuit voltage CCV of the battery cell 220 also decreases. Conversely, when the SOC increases due to the supply of charging power from the charging equipment, the closed circuit voltage CCV also increases.

Fig. 7 shows the time change of the closed circuit voltage. The vertical axis is in arbitrary units. The horizontal axis is time. Arbitrary units are a.d. u. is indicated. Time is denoted by T.

In addition to the closed circuit voltage, FIG. 7 also shows the driving state of the battery device 100, the actual current flowing through the assembled battery 200, and the closed circuit voltage of one battery cell 220. FIG. The drive state of the battery device 100 is denoted as DS. For simplicity of explanation, the behavior of the closed circuit voltage of the battery cell 220 and the behavior of the closed circuit voltage of the assembled battery 200 shown in the drawings are assumed to be the same. In order to clarify the behavior, the drawing shows that the closed circuit voltage of the battery cell 220 changes greatly in a short period of time.

In the initial state at time 0, the battery device 100 is in a non-driving state. The storage unit 32 does not store battery information such as closed circuit voltage and physical quantity. A system main relay that controls electrical continuity between the assembled battery 200 and various vehicle-mounted devices is in a disconnected state. Therefore, substantially no current flows through the assembled battery 200 . The closed circuit voltage of the battery cell 220 has a value in the charge/discharge region.

The SOC of the battery cell 220 decreases due to self-discharge even if the current does not substantially flow through the battery cell 220 . Therefore, in the initial state at time 0, the closed circuit voltage of the battery cell 220 tends to decrease, albeit slightly.

At time t0, the battery device 100 changes from the non-driving state to the driving state. At this time, the calculation unit 33 executes the above diagnostic processing. In order to simplify the explanation below, acquisition of the closed circuit voltage when no abnormality has occurred in the monitoring unit 10 as a result of the diagnostic processing will be explained.

At time t0, the battery device 100 changes from the non-driven state to the driven state, and the system main relay changes from the cut-off state to the energized state. As a result, supply of power supply power from the assembled battery 200 to various vehicle-mounted devices is started. An actual current begins to flow in the assembled battery 200 . The rate of decrease of the SOC of battery cell 220 increases. Along with this, the reduction rate of the closed circuit voltage of the battery cell 220 also increases.

At time t1, the calculation unit 33 acquires the closed circuit voltage of the battery cell 220. At this time, the battery information is not stored in the storage unit 32 . Therefore, the calculation unit 33 sets the acquisition range of the closed circuit voltage at the time t<b>1 to a range that the battery cell 220 can take. That is, the calculation unit 33 sets the acquisition range of the closed circuit voltage to 0.0V to 5.0V. The calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 in the acquisition range at this time t1.

At time t2, the calculation unit 33 acquires the closed circuit voltage of the battery cell 220 again. At this time, as shown in the first embodiment, the calculation unit 33 may determine the acquisition range of the closed circuit voltage at time t2 based on the closed circuit voltage of the battery cell 220 acquired at time t1. For example, if the closed circuit voltage at time t1 is 3.0V, it is conceivable to set the acquisition range of the closed circuit voltage around this 3.0V.

However, the SOC of the battery cell 220 changes while time elapses from time t1 to time t2. In the example shown in FIG. 3, the amount of power indicated by hatching is discharged. It is assumed that the closed circuit voltage at time t1 and the closed circuit voltage at time t2 are different due to this discharge.

Therefore, the calculation unit 33 calculates the median value of the acquisition range of the closed circuit voltage at time t2 based on the closed circuit voltage acquired at time t1 and the amount of change in the closed circuit voltage from time t1 to time t2. That is, the calculation unit 33 estimates the closed circuit voltage at time t2. Estimation of the closed circuit voltage at time t2 will be described in detail later. The median value of the acquisition range is a value between the upper limit value and the lower limit value of the acquisition range.

In the drawing, the tip of the dashed-dotted arrow indicates the median value of the acquisition range of the closed circuit voltage when set based only on the acquired closed circuit voltage. The tip of the solid-line arrow indicates the median value of the acquisition range of the closed-circuit voltage when set based on the acquired closed-circuit voltage and the amount of change in the closed-circuit voltage.

As indicated by the difference in the positions of the tips of these two types of arrows, the median value of the acquisition range approaches the actual value of the closed circuit voltage of the battery cell 220 at time t2 by the amount of change in the closed circuit voltage. As a result, the closed circuit voltage of the battery cell 220 moves away from the upper limit value and the lower limit value of the acquisition range. As a result of narrowing the acquisition range, the closed circuit voltage is suppressed from being unintentionally outside the acquisition range.

The acquisition range of the closed circuit voltage is indicated by the width of the solid double-ended arrow shown in FIG. The difference between the median value and the upper limit value of the limited acquisition range is set as the upper limit range width α1. The difference between the median value and the lower limit value of the limited acquisition range is set to the lower limit range width α2. These upper limit range width α1 and lower limit range width α2 may be the same or different. The upper limit range width α1 and the lower limit range width α2 are values larger than the closed circuit voltage detection error. The upper limit range width α1 and the lower limit range width α2 are values smaller than half the difference between OCV1 and OCV2 shown in FIG.

The magnitude relationship between the upper limit range width α1 and the lower limit range width α2 can be determined, for example, based on the time change of the closed circuit voltage. When the closed circuit voltage tends to decrease, the lower limit range width α2 can be set larger than the upper limit range width α1. Conversely, when the closed circuit voltage tends to increase, the upper limit range width α1 can be set larger than the lower limit range width α2. The magnitude of the difference between these two range widths can be set based on the time variation of the closed circuit voltage. A correction value for providing a difference between these two range widths is stored in the storage unit 32 .

The calculation unit 33 sets a limited acquisition range based on the upper limit range width α1, the lower limit range width α2, and the median value of the acquisition range. In this embodiment, the calculation unit 33 sets the upper limit range width α1 and the lower limit range width α2 to be the same. Therefore, in order to simplify the notation, the upper limit range width α1 and the lower limit range width α2 are collectively referred to as the range width α. Note that when the upper limit range width α1 and the lower limit range width α2 are equal to each other in this way, the median value of the acquisition range described above becomes the center value of the acquisition range.

The range width α is stored in the storage unit 32 in advance. The range width α is a value that depends on the temperature and current of the battery cell 220 . The range width α stored in the storage unit 32 is used as the width of the acquisition range at time t2.

The calculation unit 33 determines the acquisition range at time t2 by the calculation processing described above. The calculation unit 33 sets the acquisition range at time t2 to 2.65V to 2.93V, for example. The calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 in the acquisition range at this time t2.

Strictly speaking, since there is arithmetic processing in the battery device 100, the determination timing of the acquisition range and the detection timing of the closed circuit voltage at time t2 are not the same. The decision timing is before the detection timing. However, the difference between these two timings is minute. Therefore, these two timings are considered to be the same and described.

The calculation unit 33 acquires the closed circuit voltage at an acquisition cycle. The time between time t1 and time t2 corresponds to the acquisition period. This acquisition period is a time interval at which the SOC of the battery cell 220 is expected not to change suddenly unless the charge/discharge state of the battery cell 220 changes suddenly due to constant current charging or the like. When the acquisition cycle has passed from time t1, it becomes time t2.

At time t3 after the acquisition cycle has elapsed from time t2, the calculation unit 33 determines the median value of the acquisition range based on the closed circuit voltage at time t2 and the amount of change in the closed circuit voltage from time t2 to time t3. . Further, the calculation unit 33 calculates the difference between the closed circuit voltage obtained at time t2 and the median value of the obtained range at time t2 as an estimation error. The estimation error is a larger value than the detection error.

The calculation unit 33 calculates the range width α at time t3 based on this estimated error and the range width α stored in the storage unit 32 . When the estimation error is smaller than the predetermined value, the range width α at time t3 is smaller than the range width α stored in the storage unit 32 or the range width α at time t2. When the estimation error is larger than the predetermined value, the range width α at time t3 is larger than the range width α stored in the storage unit 32 or the range width α at time t2.

By performing the arithmetic processing described above, the arithmetic unit 33 determines the acquisition range at time t3. The calculation unit 33 sets the acquisition range at time t3 to 2.60V to 2.74V, for example. The calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 in the acquisition range of this time t3.

From time t3 to time tc1, the actual current decreases. Along with this, the reduction rate of the closed circuit voltage is also reduced.

When the acquisition cycle has passed from time t3 to time t4, the calculation unit 33 calculates the closed circuit voltage at time t3, the amount of change in the closed circuit voltage from time t3 to time t4, and the range width α that takes into account the estimation error. Determine the acquisition range based on The calculation unit 33 sets the acquisition range at time t4 to 2.62V to 2.70V, for example. The calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 in the acquisition range at time t4.

Since the amount of change in closed circuit voltage between time t3 and time t4 is taken into account in this way, even if the rate of decrease in closed circuit voltage begins to decrease at time tc1 between time t3 and time t4, The closed circuit voltage acquired by the calculation unit 33 at time t4 falls within the acquisition range.

From time t4 to time tc2, the charging equipment is connected to the electric vehicle. The charging equipment charges the assembled battery 200 with a constant current. This causes the actual current to rise sharply. The calculation unit 33 acquires such information from vehicle information or charging information.

At time t5 after the acquisition cycle has passed from time t4, the calculation unit 33 calculates the closed circuit voltage at time t4, the amount of change in the closed circuit voltage from time t4 to time t5, and the range width α that takes into account the estimation error. Determine the acquisition range based on The calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 in the acquisition range at this time t5.

Since the amount of change in the closed circuit voltage between time t4 and time t5 is taken into account in this way, even if the closed circuit voltage begins to rise sharply at time tc2 between time t4 and time t5, the calculation at time t5 The closed circuit voltage acquired by the unit 33 falls within the acquisition range.

It should be noted that when constant-current charging is performed in this manner, the rate of change of the closed circuit voltage per unit time increases. Therefore, the range width α at time t5 may be amplified and corrected more than the range width α at time t4. Alternatively, the range width α during constant current charging may be stored in the storage unit 32 . This range width α may be used at time t5. The calculation unit 33 sets the acquisition range at time t5 to 3.25V to 3.75V, for example.

From time t5 to time tc3, the output voltage of the assembled battery 200 reaches the target voltage. When this is detected, the calculation unit 33 terminates the constant current charging by the charging equipment. The calculation unit 33 causes the charging device to perform constant voltage charging. Note that the calculation unit 33 may perform forced charging instead of constant voltage charging after completion of constant current charging.

The amount of supplied current differs between the constant-current charging and the constant-voltage charging described above. Constant-current charging has a larger current supply than constant-voltage charging.

As described above, there is a difference of the voltage drop I×R between the closed circuit voltage CCV and the open circuit voltage OCV. During charging, CCV=OCV+I×R. Therefore, even if the maximum output voltage of the assembled battery 200 is detected as the closed circuit voltage CCV, the open circuit voltage OCV does not reach the maximum output voltage. This means that the SOC of the assembled battery 200 has not reached the full charge amount.

The above target voltage is a value based on the maximum output voltage of the assembled battery 200. When the calculation unit 33 determines that the closed circuit voltage of the assembled battery 200 has reached the target voltage, it causes the charging device to perform constant voltage charging. In constant-voltage charging, in order to avoid overcharging and bring the SOC of the assembled battery 200 closer to the full charge amount, the closed-circuit voltage detected by the assembled battery 200 is kept at the target voltage, and the charging power to the assembled battery 200 is reduced. supply takes place. The target voltage and the maximum output voltage are pre-stored in the storage section 32 .

At time t6 after the acquisition cycle has elapsed from time t5, the calculation unit 33 calculates the number of battery cells 220 detected by the monitoring unit 10 in the acquisition range determined based on the target voltage and the range width α during constant voltage charging. Get the closed circuit voltage. The calculation unit 33 sets the acquisition range at time t6 to 4.23V to 4.26V, for example.

After time t6, it is expected that the target voltage will be obtained as long as constant voltage charging continues. In this case, the calculation unit 33 continues to acquire the closed circuit voltage of the battery cell 220 within the acquisition range determined based on the target voltage and the range width α during constant voltage charging. Alternatively, the calculation unit 33 stops acquiring the closed circuit voltage. The range width α during constant-voltage charging is, for example, a smaller value than the range width α used at time t2. The range width α during constant voltage charging is stored in the storage unit 32 .

<Constant voltage drive>
When the SOC of the assembled battery 200 is excessively reduced or the electric motor of the electric vehicle malfunctions, the electric vehicle performs constant voltage drive with limited driving. At this time, the voltage of the power supply power output from the assembled battery 200 is limited. The voltage of the power supply is kept at a constant value, for example. Therefore, it is expected that the closed circuit voltage of the battery cell 220 is maintained at a predetermined voltage.

In the example shown in FIG. 8, at time tc1 between time t3 and time t4, the electric vehicle transitions from unrestricted normal drive to restricted constant voltage drive. In this case, the calculation unit 33 acquires the closed circuit voltage of the battery cell 220 in the acquisition range determined based on the predetermined voltage and the range width α during constant voltage driving at time t4. The calculation unit 33 sets the acquisition range at time t4 to 2.47V to 2.53V, for example.

After time t4, it is expected that the predetermined voltage will be obtained as long as constant voltage driving continues. In this case, the calculation unit 33 continues to acquire the closed circuit voltage of the battery cell 220 within the acquisition range determined based on the predetermined voltage and the range width α during constant voltage driving. Alternatively, the calculation unit 33 stops acquiring the closed circuit voltage.

The range width α during constant voltage driving is a smaller value than the range width α during normal driving. The range width α during constant voltage driving is stored in the storage unit 32 . Note that when the electric vehicle changes from a running state to a stopped state, there is a possibility that the closed circuit voltage may suddenly change in a short period of time. The value of the range width α may be set so as to avoid the closed-circuit voltage falling outside the acquisition range due to such a sudden change.

<Estimation of closed circuit voltage>
As described above, the calculation unit 33 calculates the median value of the acquisition range when calculating the acquisition range of the closed circuit voltage. That is, the calculation unit 33 estimates the closed circuit voltage at the time of acquisition. For example, at time t2 shown in FIG. 7, the calculation unit 33 estimates the closed circuit voltage at time t2 based on the closed circuit voltage obtained at time t1 and the amount of change in the closed circuit voltage from time t1 to time t2.

The amount of change in closed circuit voltage from time t1 to time t2 is the charge/discharge history (charge/discharge amount) between time t1 and time t2, the temperature between time t1 and time t2, and the SOC and OCV. It is calculated based on the temperature dependence of the characteristic data.

The charge/discharge history between time t1 and time t2 is calculated, for example, based on the time between time t1 and time t2 and the current between time t1 and time t2. A charge/discharge history between time t1 and time t2 is calculated as an integrated value of current between time t1 and time t2. Note that the current between time t1 and time t2 is estimated by, for example, the addition average value of the current at time t1 and the current at time t2.

The temperature between time t1 and time t2 is estimated, for example, by adding and averaging the temperature at time t1 and the temperature at time t2. The calculation unit 33 reads the SOC and OCV characteristic data of this temperature from the storage unit 32 . Then, the calculation unit 33 calculates the amount of change in closed circuit voltage from time t1 to time t2 based on the read SOC and OCV characteristic data and the calculated charge/discharge history between time t1 and time t2. . Current, temperature, and characteristic data are included in the variation.

Of course, the calculation unit 33 reads the SOC and OCV characteristic data of the battery cell 220 from the storage unit 32 among the SOC and OCV characteristic data of various secondary batteries. When the battery cell 220 is a lithium-ion secondary battery, the calculation unit 33 reads the SOC and OCV characteristic data of the lithium-ion secondary battery from the storage unit 32 .

The calculation unit 33 estimates the aged deterioration of the battery cell 220 at the time t2, for example, based on the difference between the date of manufacture of the battery cell 220 and the time t2 stored in the storage unit 32 and the deterioration determination value. good. The calculation unit 33 may estimate the internal resistance of the battery cell 220 at time t2 based on aging deterioration of the battery cell 220 and the temperature at time t2. The calculation unit 33 may calculate the voltage drop occurring in the battery cell 220 at the time t2 based on the internal resistance and the current at the time t2. The calculation unit 33 may also take this voltage drop into account to estimate the closed circuit voltage at time t2. When estimating the internal resistance in this way, the range width α may be set in consideration of the internal resistance.

Further, the calculation unit 33 may estimate the amount of change in the closed circuit voltage from time t1 to time t2 based on the equivalent circuit model or chemical reaction model of the battery cell 220 and the current and temperature of the battery cell 220.

As a further example, the storage unit 32 may store a discharge value and a charge value for estimating the amount of change in the closed circuit voltage described above. The amount of change in closed circuit voltage may be determined by multiplying the predetermined discharge value by the time between time t1 and time t2. The amount of change in closed circuit voltage may be determined by multiplying the predetermined charge value by the time between time t1 and time t2. In this modification, the discharge value and the charge value are included in the charge/discharge amount.

<Voltage detection processing>
Next, the voltage detection processing of the calculation unit 33 will be described with reference to FIG. The calculation unit 33 executes this voltage detection process as a cycle task. The execution interval of this voltage detection process corresponds to the acquisition period described above.

In step S210, the calculation unit 33 determines whether or not the closed circuit voltage is stored in the storage unit 32. When the closed circuit voltage is stored in the storage unit 32, the calculation unit 33 proceeds to step S220. If the closed circuit voltage is not stored in the storage unit 32, the calculation unit 33 proceeds to step S230.

When proceeding to step S220, the calculation unit 33 determines whether or not constant voltage charging is being performed. If constant voltage charging is being performed, the calculation unit 33 proceeds to step S240. If the constant voltage charging is not being performed, the calculation unit 33 proceeds to step S250.

When proceeding to step S240, the calculation unit 33 sets the closed circuit voltage (estimated voltage) expected to be detected by the monitoring unit 10 as the target voltage. In other words, the calculation unit 33 sets the closed circuit voltage used for the acquisition range of the closed circuit voltage as the target voltage. After this, the calculation unit 33 proceeds to step S260.

When proceeding to step S<b>260 , the calculation unit 33 calculates the difference value between the estimated voltage and the closed circuit voltage stored in the storage unit 32 . The calculation unit 33 determines whether or not this difference value is greater than or equal to the change voltage stored in the storage unit 32 . If the difference value is greater than or equal to the change voltage, the calculation section 33 proceeds to step S270. If the difference value is smaller than the change voltage, the calculation unit 33 terminates the voltage detection process.

When proceeding to step S270, the calculation unit 33 sets a limited acquisition range of the closed circuit voltage based on the estimated voltage and various information stored in the storage unit 32. After that, the calculation unit 33 proceeds to step S280.

When the process proceeds to step S270 through step S240, the calculation unit 33 reads the range width α during constant voltage charging from the storage unit 32. The calculation unit 33 calculates the acquisition range of the closed circuit voltage based on the range width α and the target voltage. The calculation unit 33 stores this acquisition range in the storage unit 32 . Then, the calculation unit 33 proceeds to step S280.

When proceeding to step S280, the calculation unit 33 transmits an instruction signal including the acquisition range calculated in step S270 to the monitoring unit 10 as a limited range signal. After this, the calculation unit 33 proceeds to step S290.

When proceeding to step S<b>290 , the calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10 . After that, the calculation unit 33 proceeds to step S300.

When proceeding to step S<b>300 , the calculation unit 33 stores the acquired closed circuit voltage in the storage unit 32 . Also, at this time, the calculation unit 33 stores the acquisition range in the storage unit 32 . Then, the calculation unit 33 terminates the voltage detection process.

Retracing the flow, when it is determined in step S220 that constant voltage charging is not being performed and the process proceeds to step S250, the calculation unit 33 determines whether or not the electric vehicle is in constant voltage drive. That is, the calculation unit 33 determines whether or not the closed circuit voltage of the battery cell 220 is the predetermined voltage. In the case of constant voltage drive, the calculation unit 33 proceeds to step S310. If it is not constant voltage drive, the calculation unit 33 proceeds to step S320.

When proceeding to step S310, the calculation unit 33 sets the estimated voltage to a predetermined voltage. In other words, the calculation unit 33 sets the closed circuit voltage used for calculating the acquisition range of the closed circuit voltage to a predetermined voltage. After this, the calculation unit 33 proceeds to step S260.

When the process proceeds to step S270 through step S310, the calculation unit 33 reads the range width α during constant voltage driving from the storage unit 32. The calculation unit 33 sets the acquisition range of the closed circuit voltage based on the range width α and the predetermined voltage.

Retracing the flow, when it is determined in step S250 that the constant voltage drive is not performed and the process proceeds to step S320, the calculation unit 33 acquires various information for calculating the estimated voltage. This information includes closed-circuit voltage, acquisition cycle, current, temperature, SOC and OCV characteristic data, and the like stored in the storage unit 32 . After that, the calculation unit 33 proceeds to step S330.

When proceeding to step S330, the calculation unit 33 calculates the estimated voltage based on the various information acquired in step S320. After this, the calculation unit 33 proceeds to step S260.

When proceeding to step S270 through step S330, the calculation unit 33 reads the range width α from the storage unit 32. The calculation unit 33 sets the acquisition range of the closed circuit voltage based on the range width α and the estimated voltage.

As mentioned above, the voltage detection process is a cycle task. If step S280 has been performed in the previous voltage detection process, in step S270 the calculation unit 33 calculates the estimated error by subtracting the closed circuit voltage stored in the storage unit 32 from the estimated voltage. The calculation unit 33 sets the acquisition range of the closed circuit voltage based on the range width α and the estimated voltage. Unlike this, when step S230 has been executed in the previous voltage detection process, the calculation unit 33 stops calculating the estimation error. In this case, the calculation unit 33 sets the acquisition range of the closed circuit voltage based on the range width α and the estimated voltage.

Retracing the flow, when it is determined in step S210 that the closed circuit voltage is not stored in the storage unit 32 and the process proceeds to step S230, the calculation unit 33 converts the instruction signal including the possible acquisition range of the closed circuit voltage into a full range signal. Send to the monitoring unit 10 . After that, the calculation unit 33 proceeds to step S290.

Note that the calculation unit 33 does not have to execute steps S220, S240, S250, and S310 shown in FIG. In this case, as shown in FIG. 10, when it is determined in step S210 that the closed circuit voltage is stored in the storage unit 32, the calculation unit 33 proceeds to step S320.

<Effect>
As described above, the calculation unit 33 calculates the closed circuit voltage based on the past closed circuit voltage stored in the storage unit 32 and the amount of change in the closed circuit voltage of the battery cell 220 until the closed circuit voltage is acquired again. Set the acquisition range of .

For example, the calculation unit 33 changes the acquisition range of the closed circuit voltage from the possible acquisition range of 0.0V to 5.0V to the limited acquisition range of 2.65V to 2.93V. In this limited acquisition range, the analog closed-circuit voltage is converted into a digital signal by the AD converter 13 . This reduces the quantization error of the AD converter 13 . As a result, the detection accuracy of the closed circuit voltage is improved.

In addition, as described above, the calculation unit 33 sets the acquisition range of the closed circuit voltage in consideration of the amount of change in the closed circuit voltage of the battery cell 220 until the closed circuit voltage is acquired again. Therefore, the closed circuit voltage is suppressed from being out of the acquisition range.

The range width α of the acquisition range is obtained by adding the difference (estimation error) between the past closed circuit voltage stored in the storage unit 32 and the median value of the acquisition range of the closed circuit voltage set when the closed circuit voltage is detected. have decided. According to this, it is effectively suppressed that the closed circuit voltage is out of the acquisition range.

When the estimated error is smaller than a predetermined value, the calculation unit 33 narrows the range width α. This narrows the acquisition range of the closed circuit voltage. Detection accuracy of the closed circuit voltage is improved.

When the difference value between the estimated voltage and the closed circuit voltage stored in the storage unit 32 is smaller than the change voltage, the calculation unit 33 stops setting a new acquisition range. According to this, the arithmetic processing in the arithmetic unit 33 is simplified.

Note that the battery device 100 described in this embodiment includes components equivalent to those of the battery device 100 described in the first embodiment. Therefore, it goes without saying that the battery device 100 of this embodiment has the same effect as the battery device 100 described in the first embodiment. Therefore, description thereof is omitted. Descriptions of effects that overlap with other embodiments described below will be omitted.

(Third Embodiment)
Next, a third embodiment will be described with reference to FIGS. 11 to 13. FIG.

In the previous embodiments, an example was shown in which the closed circuit voltage was detected within the acquisition range. On the other hand, in the present embodiment, processing when the closed circuit voltage is not detected within the acquisition range will be described.

In the example shown in FIG. 11, the calculation unit 33 sets the acquisition range of the closed circuit voltage at time t3 based on the closed circuit voltage acquired at time t2. However, if a ground fault occurs at time ta between time t2 and time t3, the closed circuit voltage detected by monitoring unit 10 at time t3 will be outside the acquisition range. The closed circuit voltage acquired by the calculation unit 33 is the lower limit value of the acquisition range.

When the lower limit value of the acquisition range is acquired in this way, the calculation unit 33 resets the acquisition range of the closed circuit voltage to a range that the closed circuit voltage can take. By expanding the acquisition range in this way, it becomes possible to detect the closed circuit voltage at time t4.

In the case of a permanent ground fault rather than a temporary ground fault, 0.0 V is detected by the monitoring unit 10 at times t3, t4, t5, and t6 after time ta, as shown in FIG. The calculation unit 33 acquires 0.0V multiple times. When the number of acquisitions of 0.0 V is equal to or greater than the short-circuit determination value, the calculation unit 33 determines that a ground fault has occurred.

This short circuit determination value is stored in the storage unit 32 as a reference value. The value of the short circuit determination value is not particularly limited. The short circuit determination value is set to 3 in this embodiment.

In the example shown in FIG. 12, the calculation unit 33 sets the acquisition range of the closed circuit voltage at time t3 based on the closed circuit voltage acquired at time t2. However, if a power fault occurs at time ta between time t2 and time t3, the closed circuit voltage detected by monitoring unit 10 at time t3 is out of the acquisition range. The closed circuit voltage acquired by the calculation unit 33 is the upper limit value of the acquisition range.

When the upper limit value of the acquisition range is acquired in this way, the calculation unit 33 resets the acquisition range of the closed circuit voltage to the possible range of the closed circuit voltage as described with reference to FIG.

In the case of a permanent power fault rather than a temporary power fault, the monitoring unit 10 detects 5.0 V at times t3, t4, t5, and t6 after time ta, as shown in FIG. The calculation unit 33 acquires 5.0V multiple times. When the number of acquisitions of 5.0 V is equal to or greater than the short-circuit determination value, the calculation unit 33 determines that a power fault has occurred.

<Short Circuit Determination Processing>
Next, the short-circuit determination processing of the calculation unit 33 will be described with reference to FIG. 13 . The calculation unit 33 executes this short-circuit determination process as a cycle task at an acquisition cycle. The calculation unit 33 acquires the closed circuit voltage within a certain acquisition range before executing this short-circuit determination process. The acquisition range and closed circuit voltage are stored in the storage unit 32 .

At step S410, the calculation unit 33 determines whether the closed circuit voltage is the upper limit value or the lower limit value of the acquisition range. That is, the calculation unit 33 determines whether or not the closed circuit voltage is a value excluding the upper limit value and the lower limit value of the acquisition range. If the closed circuit voltage is the upper limit value or the lower limit value of the acquisition range, the calculation unit 33 proceeds to step S420. If the closed circuit voltage is a value excluding the upper limit value and the lower limit value of the acquisition range, the calculation unit 33 proceeds to step S430.

When proceeding to step S420, the calculation unit 33 increments its own counter by one. After that, the calculation unit 33 proceeds to step S440.

When proceeding to step S440, the calculation unit 33 determines whether or not the value of the counter is smaller than the short-circuit determination value. When the value of the counter is smaller than the short-circuit determination value, the operation section 33 proceeds to step S450. When the value of the counter is equal to or greater than the short-circuit determination value, the operation section 33 proceeds to step S460.

When proceeding to step S450, the calculation unit 33 transmits an instruction signal including an acquisition range different from the acquisition range stored in the storage unit 32 to the monitoring unit 10 as a range signal. In the case of this embodiment, the calculation unit 33 causes the range signal to include the possible range of the closed circuit voltage. If the entire range is stored in the storage unit 32, an instruction signal including the entire range is transmitted to the monitoring unit 10 as a range signal. Alternatively, the calculation unit 33 stops outputting the range signal. After that, the calculation unit 33 proceeds to step S470.

When proceeding to step S470, the calculation unit 33 acquires the closed circuit voltage detected by the monitoring unit 10. After this, the calculation unit 33 returns to step S410.

When a ground fault or power fault occurs as shown in FIGS. 11 and 12, the calculation unit 33 repeats steps S410, S420, S440, S450, and S470. It is repeated that the closed circuit voltage becomes the upper limit value or the lower limit value of the acquisition range. As a result, the value of the counter becomes equal to or greater than the short circuit determination value.

When the value of the counter is not equal to or greater than the short-circuit determination value and the closed circuit voltage is stored in the storage unit 32, the calculation unit 33 estimates the SOC based on the stored closed circuit voltage. Then, the calculation unit 33 executes calculation processing based on the estimation result.

When it is determined in step S440 that the counter value is equal to or greater than the short-circuit determination value and the process proceeds to step S4600, the calculation unit 33 determines that a short-circuit such as a ground fault or power fault has occurred. Then, the calculation unit 33 terminates the short-circuit determination process.

Retracing the flow, when it is determined in step S410 that the closed circuit voltage is neither the upper limit value nor the lower limit value of the acquisition range and the process proceeds to step S430, the calculation unit 33 clears the counter. The calculation unit 33 sets the value of the counter to zero. Then, the calculation unit 33 proceeds to step S480.

When proceeding to step S480, the calculation unit 33 determines that a short circuit has not occurred. Then, the calculation unit 33 proceeds to step S490.

When proceeding to step S490, the calculation unit 33 stores the acquired closed circuit voltage in the storage unit 32. Then, the calculation unit 33 terminates the short-circuit determination process.

<Effect>
As described above, when the closed circuit voltage is outside the acquisition range, the calculation unit 33 changes the acquisition range of the closed circuit voltage. The calculation unit 33 changes the acquisition range so that the closed circuit voltage is detected. The calculation unit 33 of the present embodiment changes the acquisition range to a possible acquisition range of the closed circuit voltage.

According to this, as a result of narrowing the acquisition range, it is suppressed that the closed circuit voltage cannot be detected.

The calculation unit 33 determines that a short circuit has occurred when the number of acquisitions of the lower limit value or the upper limit value of the acquisition range of the closed circuit voltage is greater than or equal to the short circuit determination value. Specifically, when the number of acquisitions of 0.0 V is 3 or more, the calculation unit 33 determines that a ground fault has occurred. When the number of acquisitions of 5.0 V is 3 or more, the calculation unit 33 determines that a power fault has occurred.

This suppresses erroneous judgment of short circuits. A ground fault and a power fault can be detected separately.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS. 14 and 15. FIG.

In the third embodiment, when the closed circuit voltage of the upper limit value or the lower limit value of the acquisition range is acquired, the calculation unit 33 resets the acquisition range of the closed circuit voltage to the possible range of the closed circuit voltage. Then, an example of continuing to acquire the closed circuit voltage within a possible range was shown. On the other hand, in this embodiment, when the closed circuit voltage of the upper limit value or the lower limit value is acquired in the range that can be taken, the calculation unit 33 narrows the acquisition range to the vicinity of the acquired closed circuit voltage.

As shown in FIG. 14, when the operating unit 33 acquires the lower limit value of the closed circuit voltage within the possible range of the closed circuit voltage, the calculation unit 33 sets the acquisition range of the closed circuit voltage to include the closed circuit voltage. The calculation unit 33 sets the acquisition range to around 0.0V. The calculation unit 33 sets the width of the acquisition range to a value smaller than the range width α stored in the storage unit 32 . Thereby, a ground fault can be detected with high accuracy.

As shown in FIG. 15, when the operating unit 33 acquires the upper limit value of the closed circuit voltage within the possible range of the closed circuit voltage, the calculation unit 33 sets the acquisition range of the closed circuit voltage to include the closed circuit voltage. The calculation unit 33 sets the acquisition range to around 5.0V. The calculation unit 33 sets the width of the acquisition range to a value smaller than the range width α. This makes it possible to detect power faults with high accuracy.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIG.

In the third embodiment, when the closed circuit voltage of the upper limit value or the lower limit value of the acquisition range is detected, the calculation unit 33 resets the acquisition range of the closed circuit voltage to a range that the closed circuit voltage can take. On the other hand, in the present embodiment, each time the closed circuit voltage of the upper limit value or the lower limit value of the acquisition range is acquired, the calculation unit 33 gradually expands the acquisition range of the closed circuit voltage as shown in FIG. 16 .

(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS. 17 and 18. FIG.

In the fourth embodiment, the calculation unit 33 gradually expands the acquisition range of the closed circuit voltage each time the closed circuit voltage of the upper limit value or the lower limit value of the acquisition range is acquired. In contrast, in the present embodiment, each time the closed circuit voltage at the lower limit of the acquisition range is acquired, the calculation unit 33 gradually shifts the acquisition range of the closed circuit voltage to 0.0 V as shown in FIG. Each time the closed circuit voltage of the upper limit value of the acquisition range is acquired, the calculation unit 33 gradually shifts the acquisition range of the closed circuit voltage to 5.0 V as shown in FIG. 18 .

When the calculation unit 33 acquires 0.0V in the acquisition range including 0.0V, it determines that a ground fault has occurred. When the calculation unit 33 obtains 5.0V in the acquisition range including 5.0V, it determines that a power fault has occurred.

(Seventh embodiment)
Next, a seventh embodiment will be described with reference to FIGS. 19 and 20. FIG.

In the third embodiment, when the closed circuit voltage is the upper limit value or the lower limit value of the acquisition range, the calculation unit 33 resets the acquisition range of the closed circuit voltage to a possible range of the closed circuit voltage. On the other hand, in this embodiment, when the closed circuit voltage is the upper limit value or the lower limit value of the acquisition range, the calculation unit 33 sets the acquired closed circuit voltage to the new lower limit value or upper limit value of the acquisition range.

When the closed circuit voltage is the lower limit of the acquisition range, the calculation unit 33 sets the upper limit of the new acquisition range to the acquired closed circuit voltage, as indicated by the dashed line in FIG. Then, the calculation unit 33 sets the lower limit value of the new acquisition range to the lower limit value of the possible range.

When the closed circuit voltage is the upper limit value of the acquisition range, the calculation unit 33 sets the lower limit value of the new acquisition range to the acquired closed circuit voltage, as indicated by the dashed line in FIG. Then, the calculation unit 33 sets the upper limit value of the possible range as the upper limit value of the new acquisition range.

According to this, the deterioration of the detection accuracy of the closed circuit voltage due to the resetting of the acquisition range is suppressed.

(Other modifications)
In this embodiment, an example is shown in which one control unit 30 is provided for a plurality of monitoring units 10 . However, a configuration in which a plurality of controllers 30 are provided individually for a plurality of monitoring units 10 can also be adopted.

In this embodiment, an example of setting the acquisition range of the closed circuit voltage of each of the plurality of battery cells 220 has been shown. However, it is also possible to employ a configuration in which the acquisition range of the closed circuit voltage of each of the plurality of battery stacks 210 is set. It is also possible to employ a configuration in which a common closed-circuit voltage acquisition range is set for each of the plurality of battery cells 220 included in one battery stack 210 . In such a modification, the assembled battery 200 has at least two battery stacks 210 .

In this embodiment, an example is shown in which each of the plurality of battery cells 220 is the same type of secondary battery. However, a secondary battery in which some of the plurality of battery cells 220 are different may be used. For example, some battery stacks 210 among the plurality of battery stacks 210 include first type battery cells 220, and the remaining battery stacks 210 include second type battery cells 220 different from the first type. may As the battery cells 220 of different types, for example, battery cells 220 having the same internal configuration and external configuration but different composition materials for the positive and negative electrodes can be employed.

In the case of such a modification, when estimating the amount of change in the closed circuit voltage, the calculation unit 33 uses the SOC and OCV characteristic data of the first type battery cell 220 and the SOC and OCV characteristic data of the second type battery cell 220 Data is read from the storage unit 32 .

Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, while various combinations and configurations are shown in this disclosure, other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure. is to enter.

(Technical idea)
This specification includes various technical ideas described below.

<Set acquisition range>
[Technical thought 1]
a storage unit (32) for storing battery information including the closed circuit voltages of the plurality of electrically connected battery cells (220) and the amount of change in the closed circuit voltage;
a setting unit (33) for setting an acquisition range of the closed circuit voltage based on the battery information;
a detection unit (11) for detecting the closed circuit voltage;
a conversion unit (12, 13) that converts the closed circuit voltage detected by the detection unit into a digital signal within the acquisition range set by the setting unit.
[Technical thought 2]
The amount of change includes a period from a first detection timing at which the closed-circuit voltage stored in the storage unit is detected by the detection unit to just before a second detection timing at which the closed-circuit voltage is newly detected by the detection unit. The battery device according to Technical Idea 1, wherein the charge/discharge amount of the battery cell is included between.
[Technical thought 3]
The battery device according to technical idea 2, wherein the setting unit sets the median value of the acquisition range of the second detection timing based on the closed circuit voltage and the amount of change stored in the storage unit.
[Technical Thought 4]
The setting unit sets the width of the acquisition range at the second detection timing based on a difference between the closed-circuit voltage stored in the storage unit and a median value of the acquisition range at the first detection timing. The battery device according to technical idea 3.
[Technical Thought 5]
The setting unit sets an upper limit range width of a difference between a median value of the acquisition range at the second detection timing and an upper limit value of the acquisition range at the second detection timing, and a center of the acquisition range at the second detection timing. The battery device according to technical idea 3 or 4, wherein a magnitude relationship of a lower limit range width of a difference between the value and the lower limit value of the acquisition range of the second detection timing is set based on the change amount.
[Technical thought 6]
The setting unit sets the lower limit range width larger than the upper limit range width when the amount of change tends to decrease, and sets the upper limit range width larger than the lower limit range width when the amount of change tends to increase. The battery device according to technical idea 5 to be set.
[Technical Thought 7]
The setting unit configures the acquisition range at the second detection timing when a difference value between the median value of the acquisition range at the second detection timing and the closed circuit voltage stored in the storage unit is equal to or greater than the change voltage. 7. Technical ideas according to any one of 3 to 6, wherein a new setting is determined and the new setting of the acquisition range at the second detection timing is stopped when the difference value is lower than the change voltage battery device.
[Technical Thought 8]
8. The battery device according to any one of technical ideas 2 to 7, wherein when the closed circuit voltage is a predetermined voltage, the setting unit sets the median value of the acquisition range of the second detection timing to the predetermined voltage.

<Change of acquisition range>
[Technical thought 1]
a storage unit (32) for storing battery information including closed circuit voltages of a plurality of electrically connected battery cells (220);
a setting unit (33) for setting an acquisition range of the closed circuit voltage based on the battery information;
a conversion unit (12, 13) that converts the closed circuit voltage into a digital signal within the acquisition range set by the setting unit;
The battery device, wherein the setting unit changes the acquisition range when the closed circuit voltage is one of an upper limit value and a lower limit value of the acquisition range.
[Technical thought 2]
The battery device according to Technical Idea 1, wherein the setting unit expands the acquisition range when the closed circuit voltage is one of an upper limit value and a lower limit value of the acquisition range.
[Technical thought 3]
The battery device according to technical idea 2, wherein, when the closed circuit voltage is one of the upper limit value and the lower limit value of the obtained range, the setting unit changes the acquisition range to a range that the closed circuit voltage can take.
[Technical Thought 4]
When the acquisition range is the possible range, and the closed circuit voltage is one of the upper limit value and the lower limit value of the possible range, the setting unit sets the acquisition range to the upper limit value of the possible range. The battery device according to technical idea 3, which is changed to a limited range including one of the lower limits.
[Technical Thought 5]
Technical idea 1 or technical idea 1 for changing the new acquisition range to a range transitioned to the closed circuit voltage side when the closed circuit voltage is one of the upper limit value and the lower limit value of the acquisition range. The battery device according to Thought 2.
[Technical thought 6]
The setting unit
if the closed circuit voltage is the upper limit of the acquisition range, the new lower limit of the acquisition range is set to the closed circuit voltage;
The battery device according to technical idea 1 or technical idea 2, wherein, when the closed circuit voltage is the lower limit of the acquisition range, the closed circuit voltage is set as the new upper limit of the acquisition range.
[Technical Thought 7]
7. Technical ideas according to any one of technical ideas 1 to 6, wherein the setting unit determines that a short circuit occurs when the closed circuit voltage is one of the upper limit value and the lower limit value of the acquisition range multiple times. battery device.

Claims (9)

1. a level shifter (12) comprising a plurality of range setting units (122, 123) for changing an acquisition range of closed circuit voltages of a plurality of electrically connected battery cells (220);
   an AD converter (13) that converts the closed-circuit voltage output from the level shifter into a digital signal within the acquisition range set by the level shifter;
   a reference signal unit (16) for outputting to the level shifter a reference signal for diagnosing the state of each of the plurality of range setting units.
2. The level shifter has an operational amplifier (121) in addition to the plurality of range setting units,
   2. The monitoring device according to claim 1, wherein each of the plurality of range setting units has an offset adjustment unit (122) that adjusts the offset of the operational amplifier and a gain adjustment unit (123) that adjusts the gain of the operational amplifier.
3. The operational amplifier has a plurality of input terminals and output terminals,
   3. The monitoring apparatus according to claim 2, wherein said offset adjustment section is connected to each of said plurality of input terminals, and said plurality of gain adjustment sections are provided between said plurality of input terminals and said plurality of output terminals.
4. a level shifter (12) comprising a plurality of range setting units (122, 123) for changing an acquisition range of closed circuit voltages of a plurality of electrically connected battery cells (220);
   an AD conversion unit (13) that converts the closed circuit voltage output from the level shifter into a digital signal within the acquisition range set by the range setting unit;
   a reference signal unit (16) for outputting a reference signal for diagnosing the state of each of the plurality of range setting units to the level shifter;
   a plurality of the reference signals converted into digital signals by the AD converter in each of the plurality of acquisition ranges set by each of the plurality of range setting units; and a voltage level of the reference signal output from the reference signal unit. and a determination unit (33) that determines which of the plurality of range setting units has an abnormality based on the above.
5. 5. The battery device according to claim 4, wherein the determination unit determines whether the acquisition range can be set using at least one of the plurality of range setting units including the range setting unit in which an abnormality has occurred. .
6. The level shifter has an operational amplifier (121) in addition to the plurality of range setting units,
   Each of the plurality of range setting units has an offset adjustment unit (122) that adjusts the offset of the operational amplifier and a gain adjustment unit (123) that adjusts the gain of the operational amplifier,
   The determination unit includes a plurality of the reference signals converted into digital signals by the AD conversion unit in each of the plurality of acquisition ranges set by a combination of the plurality of offset adjustment units and the plurality of gain adjustment units; 5. The battery device according to claim 4, wherein it is determined which of the plurality of offset adjustment units and the plurality of gain adjustment units has an abnormality based on the voltage level.
7. The determination unit uses at least one of a plurality of offset adjustment units and a plurality of gain adjustment units including at least one of the abnormal offset adjustment unit and the abnormal gain adjustment unit. 7. The battery device according to claim 6, wherein it is determined whether the acquisition range can be set.
8. The operational amplifier has a plurality of input terminals and output terminals,
   The determination unit is set by a combination of a plurality of the offset adjustment units connected to the plurality of input terminals respectively and a plurality of the gain adjustment units provided between the plurality of the input terminals and the plurality of the output terminals. any one of the plurality of offset adjustment units and the plurality of gain adjustment units based on the plurality of reference signals converted into digital signals by the AD conversion unit and the voltage level in each of the plurality of acquisition ranges obtained by 8. The battery device according to claim 6 or 7, wherein it is determined whether there is an abnormality in the battery.
9. The determination unit prohibits the use of the current path between the input terminal and the output terminal to which at least one of the offset adjustment unit with the abnormality and the gain adjustment unit with the abnormality is connected. The battery device according to claim 8.

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