JP7552467B2 - Battery management device and battery device - Google Patents

Description

The disclosure in this specification relates to a battery management device and a battery device.

Patent document 1 discloses a battery device that performs equalization processing for each battery block in order to quickly reduce voltage variations among multiple batteries.

JP 2010-141957 A

In devices that manage the state of batteries, it is important to perform highly accurate battery equalization, estimation of the battery's state of charge (SOC), and estimation of the battery's state of health (SOH). To achieve this, there is a demand for improved accuracy in measuring battery voltage.

One of the objectives disclosed in this specification is to provide a battery management device and a battery device that can improve the accuracy of voltage measurement.

The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. Furthermore, the symbols in parentheses in the claims and in this section are merely examples showing the correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope.

One of the battery management devices disclosed includes a range setting unit (1) that sets a limited measurement range that limits the voltage measurement range for multiple in-vehicle batteries (7), and a measurement unit (3; 103) that measures the battery voltage within the limited measurement range set by the range setting unit , and the range setting unit sets the limited measurement range to include the battery voltage measured by the measurement unit based on the battery voltage .

One of the battery devices disclosed comprises a plurality of batteries (7) for vehicle use, a range setting unit (1) that sets a limited measurement range that limits the voltage measurement range for the batteries, and a measurement unit (3; 103) that measures the voltage of the batteries within the limited measurement range set by the range setting unit , and the range setting unit sets the limited measurement range to include the voltage of the batteries based on the voltage measured by the measurement unit .

According to this technology, the range setting unit (1) can set a limited voltage measurement range within the entire voltage range of the battery (7). Since an appropriate voltage measurement range can be set, the accuracy of voltage measurement can be improved.

FIG. 2 is a configuration diagram of a battery device. FIG. 2 is a configuration diagram of a monitoring IC. FIG. 4 is a characteristic diagram showing the relationship between OCV and SOC of a battery cell. 4 is a flowchart showing battery management in the first embodiment. 10 is a flowchart showing battery management according to a second embodiment. FIG. 4 is a characteristic diagram illustrating a calculation related to SOH estimation. 13 is a flowchart showing battery management according to a third embodiment. 13 is a flowchart showing battery management according to a fourth embodiment. FIG. 13 is a configuration diagram of a monitoring IC according to a fifth embodiment. 4 is a timing chart for explaining voltage detection. 4 is a timing chart for explaining voltage detection. 11 is a flowchart illustrating an acquisition target setting process.

Below, several embodiments for implementing the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment may be given the same reference numerals, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other previously described embodiments may be applied to the other parts of the configuration. In addition to combinations of parts that are specifically specified as being possible in each embodiment, it is also possible to partially combine embodiments even if not specified, as long as there is no particular problem with the combination.

First Embodiment
A first embodiment will be described with reference to Figures 1 to 4. A battery management device capable of achieving the object specified in the specification can be applied to management of secondary batteries mounted on vehicles such as hybrid cars, electric cars, and fuel cell cars. Vehicles include passenger cars, buses, construction vehicles, agricultural machinery vehicles, and the like. The secondary batteries that can be used include lithium ion secondary batteries, nickel metal hydride secondary batteries, and organic radical batteries.

Figure 1 shows the configuration of the battery device 200 and an external device that charges the battery pack 5. The battery device 200 includes the battery pack 5 and a battery management device 100.

The battery management device 100 includes a control device 10 for the battery pack 5. The external device includes a charging facility (CF) 12 and a charging terminal (CT) 11. A charging/discharging circuit (CDC) 8 mounted on the vehicle enables power to be exchanged between the battery pack 5 and the charging terminal 11.

The battery management device 100 is provided in the vehicle. The battery management device 100 functions as a management device that monitors and controls charging and discharging of the battery pack 5 including the secondary battery in the vehicle. The battery pack 5 can be charged by an external device.

Power processing is provided between the battery management device 100 and the charging equipment 12, allowing power to flow in one direction or two directions. The charging equipment 12 is a power source device installed in a home, business, etc. The charging equipment 12 is configured as a simple power outlet or a charging stand for charging.

The charging terminal 11 is a portable or stationary device. The charging terminal 11 can be placed in a charging facility 12 or a vehicle. The charging terminal 11 communicates with the vehicle using a dedicated signal line. The charging terminal 11 can also be configured as a charger. The system main relay 6 can switch the charging terminal 11 and the battery pack 5 between a current-carrying state and a current-delaying state.

The charging equipment 12 includes an AC power source and an outlet that outputs power supplied from the AC power source. The AC power source is supplied from a small-scale power generation facility or a wide-area power grid. The outlet is located outside the facility that provides the charging equipment 12 and is capable of accepting a specified plug. The outlet and plug provide a connection device that connects between the charging equipment 12 and the charging terminal 11.

A vehicle equipped with the battery management device 100 has an inlet. The inlet provides an input side connector for the charging terminal 11. The inlet has a terminal group including multiple terminals for DC power and multiple terminals for data communication.

The charging terminal 11 includes a plug that can be connected to an outlet of the charging equipment 12. The plug is capable of carrying AC power. The charging terminal 11 includes a connector that can be connected to an inlet of a vehicle. The connector is also called a charging gun. The connector has a terminal group including multiple terminals for AC power and multiple terminals for data communication. The inlet of the vehicle and the connector of the charging terminal 11 provide a connection device that connects the charging terminal 11 to the vehicle. The charging terminal 11 includes a control device that adjusts the power supplied to the plug of the charging terminal 11 and supplies it to the connector. The control device of the charging terminal 11 includes a switch circuit that turns on and off the power supply to the connector. The control device of the charging terminal 11 may include a voltage conversion circuit.

The control device of the charging terminal 11 is also a communication device for communicating with the vehicle via the connector of the charging terminal 11. The control device of the charging terminal 11 cooperates with the control device 10 of the battery management device 100 to execute a charging process that controls charging to the assembled battery 5. The control device of the charging terminal 11 transmits a signal indicating that power supply from the charging terminal 11 is possible by a CPLT signal. The control device of the charging terminal 11 also receives a signal indicating that discharging from the assembled battery 5 is possible by a CPLT signal. The control device of the charging terminal 11 interrupts the power supply from the charging terminal 11 to the assembled battery 5.

The battery pack 5 supplies power to the traction motor installed in the vehicle. The battery pack 5 has a high capacity and high voltage that allows it to be used as a power source for driving the vehicle. The battery pack 5 includes a group of multiple batteries connected in series or parallel. The battery group includes a group of multiple battery cells 7 connected in series. The battery cells 7 are secondary batteries.

The vehicle is equipped with a charge/discharge circuit 8. The charge/discharge circuit 8 functions as a charge circuit that rectifies and transforms the power supplied to the vehicle inlet and supplies it to the battery pack 5. The charge/discharge circuit 8 can also function as a discharge circuit that converts DC power obtained from the battery pack 5 into AC power and outputs it to the vehicle inlet. The charge/discharge circuit 8 enables charging of the battery pack 5 from the AC power source of the charging equipment 12 and reverse power flow from the battery pack 5 to the AC power source. The charge/discharge circuit 8 can include an inverter circuit and a voltage converter circuit. The control device 10 of the battery management device 100 controls the charge/discharge circuit 8.

The control device 10 includes a monitoring IC (BMIC) 3, an insulating element (IE) 2, and a microcomputer (μC) 1. The monitoring IC 3 functions as a measurement unit that measures the voltage (terminal voltage) between the anode and negative electrode of each battery cell 7. One monitoring IC 3 measures, for example, the terminal voltage of each battery cell 7 included in one battery group.

The microcomputer 1 and each monitoring IC 3 are insulated by an insulating element 2. The microcomputer 1 acquires the inter-terminal voltage measured by each monitoring IC 3 via the insulating element 2. The microcomputer 1 monitors each battery cell 7 through each monitoring IC 3, and manages the state of the assembled battery 5, such as the charging and discharging state. The monitoring ICs 3 are insulated from each other by an insulating element (IE) 21. This insulating configuration is provided because the GND level differs for each monitoring IC 3, and to ensure communication performance.

The microcomputer 1 adjusts the voltage measurement range of the battery cell 7 to set a limited measurement range. The microcomputer 1 sets the limited measurement range when the vehicle is in a state where the influence of noise is small. The microcomputer 1 functions as a range setting unit that can set any limited measurement range from the entire range of voltage of the battery cell 7. The microcomputer 1 sets the voltage measurement range adjusted by a command sent to the monitoring IC 3 as the limited measurement range. The monitoring IC 3 interprets the command output from the microcomputer 1 and operates within the voltage measurement range included in this command.

As an example, the microcomputer 1 sets the limited measurement range using the following logic. The microcomputer 1 uses the maximum value of the voltage measurement values measured by the monitoring IC 3 for the entire range of voltage in the battery cell 7 to set a limited measurement range that includes the maximum value. The microcomputer 1 uses the minimum value of the voltage measurement values measured by the monitoring IC 3 for the entire range of voltage in the battery cell 7 to set a limited measurement range that includes the minimum value. The microcomputer 1 sets the limited measurement range using the maximum and minimum values of the voltage measurement values measured by the monitoring IC 3 for the entire range of voltage in the battery.

As shown in FIG. 2, the monitoring IC 3 includes a command section (CS) 31, an analog-to-digital converter (A/D) 32, a level shifter (L/S) 33, and a group of switches (MUX) 34. The monitoring IC 3 further includes an equalization circuit (BC) 4.

The command unit 31 includes a serial I/O, a non-volatile memory, and a digital filter, and has the function of interpreting commands from the microcomputer 1.

The analog-to-digital converter 32 has an A/D converter, which is an electronic circuit that converts an analog electrical signal into a digital electrical signal, and a clamp circuit for limiting the input range of the A/D converter. The number of quantization bits of the A/D converter is a fixed value. The input range of the A/D converter is controlled by controlling the clamp circuit with the command unit 31.

The switch group 34 has the function of arbitrarily selecting the voltage of each battery cell 7. The switch group 34 has the function of selecting multiple inputs and outputting them as a single signal.

The level shifter 33 functions as a level shifter and a gain sector. The level shifter 33 has an operational amplifier and multiple feedback circuits connected in parallel between the input terminal and the output terminal of the operational amplifier. The feedback circuit includes a switch and a capacitor connected in series. The capacitances of the capacitors included in the multiple feedback circuits may be the same or different.

The switches of the multiple feedback circuits in the level shifter 33 are selectively controlled to a conducting state or a cut-off state. This changes the number of capacitors connected between the input terminal and the output terminal of the operational amplifier. The electrostatic capacitance between the input terminal and the output terminal of the operational amplifier changes. In addition, the resistance between the input terminal and the output terminal of the operational amplifier changes. As a result, the gain and offset of the level shifter 33 are controlled.

By limiting the input range of the analog-digital converter 32 and adjusting the gain and offset of the level shifter 33, the voltage range of the analog electrical signal that is analog-digitally converted by the analog-digital converter 32 is controlled. The voltage range of the voltage of the battery cell 7 that is analog-digitally converted by the analog-digital converter 32 is controlled. As a result, the voltage measurement range is adjusted.

The monitoring IC 3 measures the voltage of the battery cell 7 within a voltage measurement range set by the microcomputer 1. The monitoring IC 3 functions as a measurement unit that measures the voltage of the battery cell 7 within a limited measurement range set by the microcomputer 1.

The battery cells 7 included in the battery pack 5 have unique characteristics regarding the relationship between the state of charge (SOC) and the open circuit voltage (OCV). In this specification, the state of charge of the battery cells 7 may be referred to as SOC. When the battery cells 7 are lithium-ion secondary batteries, the battery cells 7 have characteristic data as shown in FIG. 3 as an example. The characteristic data as shown in FIG. 3 is stored in the memory unit (ME) 22 of the control device 10. The temperature dependence of the characteristic data of the SOC and OCV of various secondary batteries is stored in the memory unit 22. The characteristic data according to the type and temperature of the battery cells 7 is read by the microcomputer 1. The memory unit 22 may be built into the microcomputer 1. In the drawings, the microcomputer 1 and the memory unit 22 are shown separately to clearly show the components.

The microcomputer 1 functions as an SOC estimation unit that estimates the SOC of the battery cell 7 by performing a calculation using the terminal voltage of the battery cell 7 measured by the monitoring IC 3 and this characteristic data. The microcomputer 1 functions as an SOC estimation unit that estimates the SOC based on the voltage measurement values measured over the entire range of measurable battery cell 7 voltages. The microcomputer 1 functions as an SOC estimation unit that estimates the SOC based on the measured voltage measurement values.

The characteristic data shown in FIG. 3 indicates the relationship between the SOC and the open circuit voltage of the battery cell 7. This characteristic data includes a low change region where the voltage change range with respect to the SOC is equal to or less than a predetermined value. The characteristic data includes a high change region where the voltage change is greater than in the low change region in both an SOC range lower than the low change region and an SOC range higher than the low change region.

The low voltage change region is the range indicated by the arrow on the vertical axis in FIG. 3. The SOC of the battery cell 7 corresponding to the low voltage change region corresponds to the range indicated by the arrow on the horizontal axis in FIG. 3. The entire range of the terminal voltage of the battery cell 7 includes the low voltage change region, where the voltage change range relative to the SOC is smaller than the low SOC region and the high SOC region.

The microcomputer 1 functions as a range setting unit that sets a limited measurement range based on the inherent characteristics of the battery cell 7 that indicate the relationship between SOC and open circuit voltage. It is preferable that the microcomputer 1 sets a voltage range included in the low change region as the limited measurement range among the entire range of voltages related to the battery cell 7. The control device 10 has a function that can perform high-precision voltage measurement and accurate estimation of the charge state for the battery cell 7 having such characteristics.

The equalization circuit 4 functions as an equalization processing unit that executes processing (equalization processing) to reduce voltage variations among the multiple battery cells 7 included in the battery group. The equalization circuit 4 includes a control unit and an equalization circuit unit. The control unit is built into the monitoring IC 3. The equalization circuit unit is connected to each battery cell 7. The equalization circuit unit is built into the monitoring IC 3. Note that the equalization circuit unit may be disposed outside the monitoring IC 3.

In the equalization process, for example, among the multiple battery cells 7 included in the battery group, the battery cells 7 that show a relatively high voltage measurement value are discharged. At the same time, among the battery cells 7 included in the battery group, the battery cells 7 that show a relatively low voltage measurement value are charged. This equalizes the SOC of the multiple battery cells 7 included in the battery group.

When the equalization processing condition is met, the microcomputer 1 sends a signal to the equalization circuit 4 to command the corresponding battery group to perform equalization processing. When the equalization processing condition is not met, the microcomputer 1 does not send a signal to the equalization circuit 4 to command the equalization processing. When the equalization processing condition is not met, the microcomputer 1 may send a signal to the equalization circuit 4 to prohibit equalization processing.

The microcomputer 1 functions as an equalization determination unit that determines whether or not to perform equalization processing depending on whether the equalization processing condition is satisfied. The microcomputer 1 determines not to perform equalization processing if the difference between the maximum voltage measurement value and the minimum voltage measurement value measured in a specific battery group among the multiple battery groups is smaller than a determination threshold. The microcomputer 1 determines to perform equalization processing if the difference between the maximum voltage measurement value and the minimum voltage measurement value is larger than the determination threshold.

The control device in this specification may also be referred to as an electronic control unit (ECU). The control device, or control system, is provided by (a) an algorithm as a plurality of logics called an if-then-else format, or (b) an algorithm as a trained model tuned by machine learning, for example, a neural network.

The control device is provided by a control system including at least one computer. The control system may include multiple computers linked by data communication devices. The computer includes at least one processor that is hardware (a hardware processor). The hardware processor may be provided by (i), (ii), or (iii) below.

(i) The hardware processor may be at least one processor core that executes a program stored in at least one memory. In this case, the computer is provided with at least one memory and at least one processor core. The processor core is called a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a RISC-CPU, etc. The memory is also called a storage medium. The memory is a non-transitive and tangible storage medium that non-temporarily stores "programs and/or data" that can be read by the processor. The storage medium is provided by a semiconductor memory, a magnetic disk, an optical disk, etc. The program may be distributed alone or as a storage medium on which the program is stored.

(ii) The hardware processor may be a hardware logic circuit. In this case, the computer is provided by a digital circuit including a large number of programmed logic units (gate circuits). The digital circuit is also called a logic circuit array, for example, ASIC: Application-Specific Integrated Circuit, FPGA: Field Programmable Gate Array, SoC: System on a Chip, PGA: Programmable Gate Array, CPLD: Complex Programmable Logic Device, etc. The digital circuit may include a memory that stores programs and/or data. The computer may be provided by an analog circuit. The computer may be provided by a combination of digital and analog circuits.

(iii) The hardware processor may be a combination of (i) and (ii) above. (i) and (ii) may be located on different chips or on a common chip. In these cases, part (ii) is also called an accelerator.

The control device, the signal source and the controlled object provide various elements, some of which may be referred to as blocks, modules or sections. Furthermore, the elements contained in the control system are referred to as functional means only if this is the case.

Next, the control related to the battery management of the control device 10 will be explained according to the flowchart in Figure 4. In this explanation, in order to clarify which component in the control device 10 is performing the process, the subject of a sentence explaining the process will be written as the component of the control device 10 that executes the process, instead of the control device 10, as necessary. Also, in the drawings, the start is indicated by an S and the end by an E.

When the power supply of the control device 10 is turned on in step S100, the control device 10 determines in step S110 whether the voltage measurement condition is met. In step S110, the control device 10 determines that there is no noise influence if the motor and engine that generate the power to run the vehicle are stopped and the battery pack 5 is not being charged or discharged. For example, if the ignition switch and motor start switch are off, the control device 10 determines that the motor and engine are stopped.

The control device 10 determines that charging and discharging of the battery is stopped, for example, when the vehicle inlet and the connector of the charging terminal 11 are not connected. When the vehicle inlet and the connector of the charging terminal 11 are not connected, the control device 10 determines that charging and discharging of the battery pack 5 are stopped. The control device 10 determines that charging and discharging of the battery pack 5 is stopped, for example, when the system main relay 6 is off and the charging terminal 11 and the battery pack 5 are not conducting electricity. The control device 10 determines that the voltage measurement condition is met when the vehicle's power equipment is stopped and charging and discharging of the battery pack 5 is stopped. When the voltage measurement condition is met, the control device 10 determines that the situation is one in which noise is tolerable.

If it is determined in step S110 that the voltage measurement condition is not met, the control device 10 ends the flowchart in FIG. 4. If it is determined in step S110 that the voltage measurement condition is met, the control device 10 proceeds to step S120. In step S120, the control device 10 determines whether or not there is a fault in the electrical circuit in the battery management device 100. The control device 10 has a function as a fault determination unit that determines whether or not there is a fault in the electrical circuit in the battery management device 100. If it is determined in step S120 that there is a fault in the electrical circuit, the control device 10 ends the flowchart in FIG. 4 without performing the process of setting the limited measurement range.

If it is determined in step S120 that there is no fault in the electrical circuit, the control device 10 proceeds to step S130. In step S130, the control device 10 determines whether or not it has an estimate of the voltage value (cell voltage) of each battery cell 7. If the current voltage value is roughly known, the control device 10 determines in step S130 that it has an estimate. For example, if the voltage value is stored in the memory unit 22, the control device 10 determines in step S130 that it has an estimate.

If it is determined in step S130 that the alignment is correct, the control device 10 proceeds to step S140. If it is determined in step S130 that the alignment is not correct, the control device 10 proceeds to step S150.

When it is determined that the voltage value of each battery cell 7 is estimated, in step S140, the microcomputer 1 outputs a command to the monitoring IC 3 to detect the voltage of the battery cell 7 within a limited range as a limit command. The command unit 31 controls the analog-to-digital converter 32 and the level shifter 33 based on the limit command to control the input range, gain, and offset. This sets the limited measurement range of the battery cell 7.

When the process proceeds to step S160 after step S140, the monitoring IC 3 of the control device 10 measures the voltage of the battery cell 7 within the limited measurement range set in step S150 and outputs the measured voltage measurement value to the microcomputer 1. The microcomputer 1 acquires the voltage measured within this limited measurement range and stores it in the memory unit 22. The control device 10 then proceeds to step S180.

Going back through the flow, if it is determined that the voltage value of each battery cell 7 is unknown, in step S150 the microcomputer 1 outputs a command to the monitoring IC 3 to detect the voltage of the battery cells 7 over the entire range as an unrestricted command. The command unit 31 controls the analog-to-digital converter 32 and the level shifter 33 based on the unrestricted command to control the input range, gain, and offset. This sets the voltage measurement range over the entire range of the battery cells 7.

When the non-limit command is received, the monitoring IC 3 measures the voltage of the battery cell 7 over the entire range in step S170 and outputs the measured voltage measurement value to the microcomputer 1. The microcomputer 1 acquires the voltage measured over this entire range and stores it in the memory unit 22. Next, the control device 10 proceeds to step S180.

In step S180, the microcomputer 1 determines whether or not to perform equalization processing on the battery group. In step S180, the microcomputer 1 determines whether or not to perform equalization processing depending on whether or not the voltage difference, which is the difference between the maximum voltage measurement value and the minimum voltage measurement value for the multiple battery cells 7 included in the battery group, is greater than a judgment threshold. If the voltage difference is smaller than the judgment threshold, the microcomputer 1 does not perform equalization processing and ends the flowchart of FIG. 4. If the voltage difference is greater than the judgment threshold, the microcomputer 1 determines that equalization processing is necessary. In step S190, the microcomputer 1 controls the equalization circuit 4 to perform equalization processing. If the voltage difference is smaller than the judgment threshold, the microcomputer 1 determines that equalization processing is unnecessary.

The judgment process in step S110 may be performed as follows. In step S110, when the power equipment that provides the driving force of the vehicle is stopped, charging and discharging of the assembled battery 5 is stopped, and the system main relay 6 is in an off state, the microcomputer 1 judges that the noise is tolerable. In step S110, if it is judged that the noise is tolerable, the microcomputer 1 judges the noise level and judges whether the noise level is tolerable. If it is judged that the noise level is tolerable, the microcomputer 1 proceeds to step S120. In this way, the microcomputer 1 may judge that the voltage measurement condition is satisfied when the noise level is tolerable in a noise tolerable situation. The control device 10 judges that the noise is tolerable when the SN ratio, which is the ratio of signal to noise, is equal to or greater than a specified value. When the SN ratio is equal to or less than a specified value, the effect of noise on the signal for voltage detection becomes large, and the effect on the voltage detection error becomes large. The source of the noise is, for example, an in-vehicle load or an external device connected to the assembled battery 5 such as a power equipment.

The effects of the battery management device 100 of the first embodiment will be described. The battery management device 100 includes a range setting unit that sets a limited measurement range that limits the voltage measurement range for the battery cells 7 included in the vehicle-mounted battery pack 5, and a measurement unit that measures the voltage of the battery cells 7 within the limited measurement range set by the range setting unit. This allows an appropriate voltage measurement range to be set to improve the accuracy of voltage measurement. The improved accuracy of voltage measurement can contribute to highly accurate estimation of SOC and SOH when these are performed using voltage measurement.

For example, the battery management device 100 narrows the voltage measurement range of the battery cell 7 from the full range of 0.0V to 5.0V to a limited measurement range of 3.0V to 3.5V. In this limited measurement range, the voltage of the battery cell 7, which is an analog electrical signal, is converted to a digital electrical signal by the analog-digital converter 32. This reduces the quantization error of the analog-digital converter 32. In the above example, the quantization error is reduced to about one-tenth. This improves the detection accuracy of the voltage of the battery cell 7.

The monitoring IC 3 adjusts the voltage measurement range in response to commands output from the microcomputer 1 to set a limited measurement range. This allows a single control device 10 to perform appropriate voltage measurements for multiple battery cells 7 with different open circuit voltage ranges.

When the range setting unit of the battery management device 100 has an idea of the voltage value of the battery cell 7, it sets a limited measurement range adjusted based on the estimated voltage value. When the range setting unit of the battery management device 100 has no idea of the voltage value of the battery cell 7, it sets a limited measurement range based on the voltage measurement values performed for the entire range of voltages. For example, when the voltage value of the battery cell 7 is not stored, the range setting unit of the battery management device 100 sets a limited measurement range based on the voltage measurement values performed for the entire range of voltages. According to this, after confirming the open circuit voltage of the battery cell 7 to be measured, the limited measurement range is set based on the confirmed measurement value. According to this setting, an appropriate voltage measurement range that improves the accuracy of voltage measurement is set.

The range setting unit of the battery management device 100 sets a limited measurement range using at least one of the maximum and minimum voltage measurement values measured over the entire voltage range. This sets the voltage measurement range to a limited measurement range that reflects the voltage value in the current state. This improves the accuracy of voltage measurement.

When the noise level is acceptable in an acceptable situation, the range setting unit sets a limited measurement range. The measurement unit measures the voltage of the battery cell 7 within this limited measurement range. This allows the voltage to be measured within the limited measurement range that was set when the noise level is acceptable in a state where the influence of noise is small. Therefore, the battery management device 100 can perform voltage measurement that separates noise and signal, further contributing to improving the accuracy of voltage measurement.

When the power equipment that provides the driving force for the vehicle is in a stopped state and charging/discharging of the battery pack 5 is stopped, the range setting unit sets a limited measurement range. The measurement unit measures the voltage of the battery cell 7 within the limited measurement range thus set. In this way, the voltage is measured within the limited measurement range set in a state where the influence of noise is small, so that voltage measurement is performed with noise and signal separated. Therefore, the battery management device 100 further contributes to improving the accuracy of voltage measurement.

The battery management device 100 includes an equalization determination unit that determines whether or not to perform equalization processing to reduce the voltage variation of multiple battery cells 7 included in a specific battery group among multiple battery groups. This equalization determination unit determines whether or not to perform equalization processing based on the voltage measurement values of the battery cells 7 measured in a limited measurement range. In this way, a highly accurate determination of whether or not to perform equalization processing can be made based on the highly accurate voltage measurement values measured in a limited measurement range.

The battery management device 100 includes an SOC estimation unit that estimates the charge rate based on characteristic data indicating the relationship between the open circuit voltage and the charge rate and the voltage measurement value of the battery cell 7 measured within the limited measurement range. This allows for highly accurate SOC estimation based on highly accurate voltage measurement values measured within the limited measurement range.

Second Embodiment
The second embodiment will be described with reference to Fig. 5 and Fig. 6. Control relating to battery management in the second embodiment will be described with reference to Fig. 5 and Fig. 6. Configurations, actions, and effects of the second embodiment that are not specifically described are the same as those of the first embodiment, and only differences from the first embodiment will be described below.

The battery management control of the second embodiment differs from the battery management control of the first embodiment only in the SOC estimation step, the SOH estimation decision step, and the implementation step. In steps S200 to S270 in the flowchart shown in FIG. 5, the same processing is performed as in steps S100 to S170 shown in FIG. 4.

As shown in FIG. 5, after performing the voltage measurement in step S260 or step S270, the control device 10 performs the process of estimating the SOC as described above in step S280. The microcomputer 1 performs the SOC estimation by calculating the SOC using the voltage measurement value and the characteristic data described above.

In step S290, the microcomputer 1 determines whether the conditions for estimating the SOH, which indicates the degree of deterioration of the battery cell 7 (SOH estimation conditions) are met. For example, the microcomputer 1 determines that the SOH estimation conditions are met when the timing of the voltage measurement used to estimate the SOC is a predetermined time after the ignition switch or motor start switch is turned off. In this case, the battery polarization is relaxed, so the microcomputer 1 allows SOH estimation.

If it is determined in step S290 that the SOH estimation conditions are not met, the flow chart in FIG. 5 ends without estimating the SOH. If it is determined in step S290 that the SOH estimation conditions are met, the microcomputer 1 estimates the SOH in step S300 and ends the flow chart in FIG. 5. The microcomputer 1 functions as a SOH estimation unit that estimates the SOH.

It is preferable that the microcomputer 1 estimates the SOH by calculating the SOH (%) using the following formula (1).

Figure 6 shows characteristic data for the battery cell 7 and a calculation for estimating the SOH. As shown in Figure 6, SOC1 and SOC2 are SOC estimates estimated using highly accurate voltage measurement values measured in a limited measurement range set by the microcomputer 1. The integral value of I is calculated by accumulating the current values from SOC1 to SOC2. The initial full charge capacity is the full charge capacity at the time of manufacture of the battery cell 7, in other words, the full charge capacity before degradation has begun.

The battery management device 100 may perform the determination process of step S290 by the following methods. The microcomputer 1 may determine that the SOH estimation condition is met when the measurement error for the voltage measurement device is smaller than a reference value. The microcomputer 1 may determine that the SOH estimation condition is met when the measurement error for the current measurement device is smaller than a reference value. The microcomputer 1 may determine that the SOH estimation condition is met when the voltage measurement device and the current measurement device are operating normally.

Third Embodiment
The third embodiment will be described with reference to Fig. 7. Control relating to battery management in the third embodiment will be described according to Fig. 7. Configurations, actions, and effects of the third embodiment that are not specifically described are the same as those of the first embodiment, and only differences from the first embodiment will be described below.

The control related to battery management in the third embodiment differs from the control in the first embodiment in that at least a part of step S110 is subdivided into steps S112, S114, and S116 and is clearly indicated. In the flowchart in FIG. 7, the same steps as those shown in FIG. 4 are given the same step numbers.

As shown in FIG. 7, in step S112, the microcomputer 1 determines whether or not there is an effect of noise. If it is determined that there is no effect of noise, the microcomputer 1 proceeds to step S120. If it is determined that there is an effect of noise, the microcomputer 1 executes the determination process of step S114.

In step S114, the control device 10 determines whether charging from an external device is currently being performed on the battery pack 5 or is being prepared for charging. The external device is, for example, a charging facility 12. The external device includes a small-scale power generation facility or a device that outputs AC power supplied from a wide-area power grid. The external device includes a power storage facility, a storage battery, etc. that outputs DC power.

If it is determined in step S114 that charging is not in progress or charging preparation is not in progress, the control device 10 ends the flowchart of FIG. 7. If it is determined in step S114 that charging is in progress or charging preparation is in progress, the control device 10 executes processing to stop charging or processing to stop charging preparation in step S116. After charging is stopped in step S116, the control device 10 executes processing from step S120 onwards as described above. According to steps S114 and S116, when charging or charging preparation is in progress to the battery pack 5, stopping this can reduce the influence of noise. This allows the setting of a limited measurement range that enables highly accurate voltage measurement.

The third embodiment provides the following effects. When the battery pack 5 is being charged from an external power source, the range setting unit sets a limited measurement range and the measurement unit measures the battery voltage within the limited measurement range while the charging is temporarily stopped. This control provides a battery management device 100 that can provide an opportunity to perform highly accurate voltage measurement even when the battery pack 5 is being charged from an external device.

Fourth Embodiment
The fourth embodiment will be described with reference to Fig. 8. Control relating to battery management in the fourth embodiment will be described according to Fig. 8. Configurations, actions, and effects of the fourth embodiment that are not specifically described are the same as those of the first embodiment, and only differences from the first embodiment will be described below.

The battery management control of the fourth embodiment differs from that of the first embodiment in that it includes steps S162, S164, and S166. In the flowchart of FIG. 8, steps that are the same as those shown in FIG. 4 are given the same step numbers.

As shown in FIG. 8, after measuring the voltage in the limited measurement range in step S160, the control device 10 executes the judgment process in step S162. In step S162, the microcomputer 1 of the control device 10 functions as an equalization judgment unit that determines a correction value for the judgment threshold used in the judgment in step S180 according to the width of the set limited measurement range. If the width of the limited measurement range is larger than the predetermined range width stored in the memory unit 22, the microcomputer 1 corrects the judgment threshold to a larger value. If the width of the limited measurement range is smaller than the predetermined range width, the microcomputer 1 corrects the judgment threshold to a smaller value.

If the width of the limited measurement range is greater than the predetermined range width, the microcomputer 1 proceeds to step S164. The microcomputer 1 executes a process of determining a judgment threshold value that is largely corrected in step S164. The microcomputer 1 determines whether or not to perform an equalization process in step S180 depending on whether or not the aforementioned voltage difference is greater than the largely corrected judgment threshold value. If the judgment threshold value is largely corrected in step S164, the equalization process is more likely not to be performed than before the correction.

If the width of the limited measurement range is smaller than the predetermined range width, the microcomputer 1 proceeds to step S166. The microcomputer 1 executes a process of determining a judgment threshold value that has been corrected to a smaller value in step S166. The microcomputer 1 determines whether or not to perform an equalization process in step S180 depending on whether or not the aforementioned voltage difference is larger than the judgment threshold value that has been corrected to a smaller value. If the judgment threshold value is corrected to a smaller value in step S166, the equalization process is more likely to be performed than before the correction.

The microcomputer 1 may set the judgment threshold according to the width of the limited measurement range by the following method. The microcomputer 1 multiplies the width of the limited measurement range by a coefficient, and corrects the judgment threshold to be smaller the smaller the width of the limited measurement range calculated in this manner. The microcomputer 1 corrects the judgment threshold to be larger the larger the width of the limited measurement range calculated in this manner. If the difference between the maximum and minimum voltage measurement values measured for a specified battery group is smaller than this judgment threshold, the microcomputer 1 determines not to perform the equalization process. If the difference between the maximum and minimum voltage measurement values described above is larger than this judgment threshold, the microcomputer 1 determines to perform the equalization process.

The fourth embodiment provides the following effects. The microcomputer 1 sets a judgment threshold according to the width of the limited measurement range. According to this control, a highly accurate judgment is made as to whether or not equalization processing is required, using the judgment threshold set according to the width of the limited measurement range. As a result, a highly accurate equalization processing is performed.

The microcomputer 1 corrects the judgment threshold to a larger value when the width of the limited measurement range is larger than the specified range width. The microcomputer 1 corrects the judgment threshold to a smaller value when the width of the limited measurement range is smaller than the specified range width. The microcomputer 1 determines not to perform equalization processing when the difference between the maximum voltage measurement value and the minimum voltage measurement value measured for a specified battery group among the multiple batteries is smaller than the judgment threshold. The microcomputer 1 determines to perform equalization processing when the difference between the maximum voltage measurement value and the minimum voltage measurement value described above is larger than the judgment threshold.

This control allows high-precision equalization processing to be performed by determining whether or not equalization processing is required based on highly accurate voltage measurement values measured in a limited measurement range. Furthermore, by using a determination threshold value corrected according to the width of the limited measurement range, a highly accurate determination of whether or not equalization processing is required is performed. As a result, high-precision equalization processing is performed.

Fifth Embodiment
The fifth embodiment will be described with reference to Fig. 9. Fig. 9 is a configuration diagram of a monitoring IC 103. Configurations, actions, and effects of the fifth embodiment that are not specifically described are similar to those of the first embodiment, and only differences from the first embodiment will be described below.

The monitoring IC 103 of the fifth embodiment includes a command unit 31, a plurality of analog-digital converters 32, a plurality of level shifters 33, and a switch group 34. The monitoring IC 103 further includes an equalization circuit 4. The analog-digital converters 32 and the level shifters 33 are provided to correspond to each other.

The monitoring IC 103 has a function of setting multiple different limited measurement ranges by being configured with multiple analog-digital converters 32 for one switch group 34. The monitoring IC 103 functions as a measurement unit that measures the voltage of the battery cell 7 in the multiple limited measurement ranges that have been set. Each analog-digital converter 32 may be configured to have a function of setting a predetermined limited measurement range. In this case, the multiple analog-digital converters 32 and level shifters 33 provided corresponding to one battery group are configured to set different predetermined limited measurement ranges.

The range setting unit of the fifth embodiment sets multiple different limited measurement ranges. This allows appropriate voltage measurements to be performed on multiple battery cells 7.

The monitoring IC 103 also has multiple level shifters 33 and analog-to-digital converters 32 for each switch group 34. This allows the voltages of multiple battery cells 7 to be measured quickly.

Of course, when the switch group 34 selects the voltages of the multiple battery cells 7 one by one, the voltage measurement range of each of the multiple battery cells 7 may be set individually by the analog-digital converter 32 and the level shifter 33. Such a configuration is applicable to all embodiments and modifications.

In addition, when the switch group 34 selects the voltages of the multiple battery cells 7 included in the battery group, a common voltage measurement range for at least some of the multiple battery cells 7 may be set by the analog-digital converter 32 and the level shifter 33. In such a configuration, the common voltage measurement range may be set as a limited measurement range based on at least one of the maximum and minimum values of the voltages measured in the selected multiple battery cells 7. Such a configuration is applicable to all embodiments and modifications.

Sixth Embodiment
The sixth embodiment will be described with reference to FIGS.

In the first embodiment, an example was shown in which the microcomputer 1 sets the voltage measurement range of the battery cell 7 when the power equipment of the vehicle is in a stopped state. An example was shown in which the microcomputer 1 sets the voltage measurement range of the battery cell 7 when the ignition switch of the vehicle is in an off state.

In contrast, in this embodiment, the microcomputer 1 sets the voltage measurement range of the battery cell 7 when the vehicle ignition switch is in the on state. The microcomputer 1 executes the setting of this voltage measurement range and voltage detection as a cycle task.

First, the detection of the voltage of the battery cell 7 will be described in detail with reference to Figure 10. Figure 10 shows the change in the voltage of the battery cell 7 over time. The vertical axis is an arbitrary unit. The horizontal axis is time. The arbitrary unit is expressed in a.u. Time is expressed as T.

Note that the battery cell 7 has an internal resistance. Therefore, there is a difference between the open circuit voltage corresponding to the SOC of the battery cell 7 and the closed circuit voltage detected by the monitoring IC 3, which is the voltage drop corresponding to this internal resistance and the current flowing through the battery cell 7. In what follows, the voltage of the battery cell 7 detected by the monitoring IC 3 will be referred to as the closed circuit voltage.

In addition to the closed circuit voltage, Figure 10 also shows the operating state of the battery management device 100, the actual current flowing through the assembled battery 5, and the closed circuit voltage of one battery cell 7. The operating state of the battery management device 100 is indicated as DS. For ease of explanation, the behavior of the closed circuit voltage of the battery cell 7 shown in the drawing is equivalent to the behavior of the closed circuit voltage of the assembled battery 5. To clearly show the behavior, the drawing shows the closed circuit voltage of the battery cell 7 changing significantly in a short period of time.

In the initial state at time 0, the vehicle ignition switch is in the off state. The battery management device 100 is in a non-driving state. No battery information such as the closed circuit voltage is stored in the memory unit 22. The system main relay 6, which controls the conduction state between the battery pack 5 and various in-vehicle devices, is in an interrupted state. As a result, substantially no current flows through the battery pack 5. The closed circuit voltage of the battery cell 7 is in the low change region.

Even if no current flows through battery cell 7, the SOC of battery cell 7 decreases due to self-discharge. Therefore, in the initial state at time 0, the closed circuit voltage of battery cell 7 tends to decrease, albeit slightly.

At time t0, the vehicle ignition switch changes from an off state to an on state. The battery management device 100 changes from a non-driven state to a driven state. The system main relay 6 changes from a disconnected state to a conductive state. This causes the battery pack 5 to start supplying power to various in-vehicle devices. Actual current begins to flow through the battery pack 5. The rate of decrease in the SOC of the battery cell 7 increases. Accordingly, the rate of decrease in the closed circuit voltage of the battery cell 7 also increases.

At time t1, the microcomputer 1 acquires the closed circuit voltage of the battery cell 7. At this time, no battery information is stored in the memory unit 22. Therefore, the microcomputer 1 sets the voltage measurement range at time t1 to the entire range. In other words, the microcomputer 1 sets the voltage measurement range to 0.0V to 5.0V.

At time t2, the microcomputer 1 again acquires the closed circuit voltage of the battery cell 7. At this time, the microcomputer 1 determines the center value of the limited measurement range at time t2 based on the closed circuit voltage of the battery cell 7 acquired at time t1. The microcomputer 1 also determines the range width α of the limited measurement range.

The voltage measurement range is indicated by the width of the arrows at both ends of the solid line shown in FIG. 10. The difference between the center value and the upper and lower limits of the limited measurement range is set to the range width α. The range width α is a value larger than the detection error of the closed circuit voltage. The range width α is a value smaller than half the difference between OCV1 and OCV2 shown in FIG. 6. The difference between the center value and the upper limit value and the difference between the center value and the lower limit value may be the same or different. In this embodiment, the range width α is a fixed value. The range width α is stored in the memory unit 22. Therefore, the limited measurement range is substantially determined based on the closed circuit voltage. The microcomputer 1 sets the limited measurement range based on this range width α and the acquired closed circuit voltage. For example, the microcomputer 1 sets the limited measurement range at time t2 to 2.8V to 3.2V. The microcomputer 1 acquires the closed circuit voltage detected by the monitoring IC 3 in the limited measurement range at time t2.

Strictly speaking, due to calculation processing in the battery management device 100, the timing at which the limited measurement range is determined at time t2 is not the same as the timing at which the closed circuit voltage is obtained. The determination timing is before the acquisition timing. However, the difference between these two timings is very small. For this reason, these two timings are described as being the same.

The microcomputer 1 acquires the closed circuit voltage at an acquisition period. This acquisition period is a time interval during which it is expected that the SOC of the battery cell 7 will not change suddenly unless the charge/discharge state of the battery cell 7 changes suddenly due to rapid charging or the like. The acquisition period is a time interval during which it is expected that the amount of change in the closed circuit voltage of the battery cell 7 will not exceed the range width α. The time t2 is reached when the acquisition period has elapsed from time t1.

When the acquisition period has elapsed from time t2 and it becomes time t3, the microcomputer 1 determines the limited measurement range based on the closed circuit voltage at time t2. For example, the microcomputer 1 sets the limited measurement range at time t3 to 2.6 V to 3.0 V. The microcomputer 1 then acquires the closed circuit voltage of the battery cell 7 detected by the monitoring IC 3 within this limited measurement range.

When the time changes from t3 to tc1, the vehicle's driving state changes. The actual current decreases. As a result, the rate of decrease in the closed circuit voltage also decreases.

When the acquisition period has elapsed from time t3 and it becomes time t4, the microcomputer 1 determines the limited measurement range based on the closed circuit voltage at time t3. For example, the microcomputer 1 sets the detection range at time t4 to 2.4V to 2.8V. The microcomputer 1 acquires the closed circuit voltage of the battery cell 7 detected by the monitoring IC 3 within this limited measurement range.

When the time progresses from time t4 to time tc2, the charging equipment 12 is connected to the vehicle via the charging terminal 11. The charging equipment 12 rapidly charges the battery pack 5. This causes the actual current to rise sharply. The microcomputer 1 obtains the relevant information from the charging equipment 12. At this time, the microcomputer 1 sets the voltage measurement range to the entire range.

When the acquisition period has elapsed from time t4 and it becomes time t5, the microcomputer 1 acquires the closed circuit voltage of the battery cell 7 detected by the monitoring IC 3 over the entire range. Due to this change in the voltage measurement range, as shown in FIG. 10, even if the closed circuit voltage suddenly rises from time tc2, the closed circuit voltage detected at time t5 falls within the voltage measurement range.

When the time passes from t5 to tc3, the output voltage of the battery pack 5 reaches the target voltage. When this is detected, the microcomputer 1 ends the rapid charging by the charging equipment 12. The microcomputer 1 causes the charging equipment 12 to perform a full charge.

The amount of current supplied differs between the quick charge and full charge described above. Quick charge supplies a larger amount of current than full charge.

There is a difference in voltage drop between the closed circuit voltage and the open circuit voltage. Therefore, even if the maximum output voltage of the battery pack 5 is detected as the closed circuit voltage, the open circuit voltage has not reached the maximum output voltage. The SOC of the battery pack 5 has not reached the full charge capacity.

The above target voltage is a value based on the maximum output voltage of the battery pack 5. When the microcomputer 1 determines that the output voltage of the battery pack 5 has reached the target voltage, it causes the charging equipment 12 to perform a full charge. In a full charge, charging power is supplied to the battery pack 5 while maintaining the output voltage of the battery pack 5 at the target voltage in order to bring the SOC of the battery pack 5 close to the full charge capacity while avoiding overcharging. The target voltage and maximum output voltage are pre-stored in the memory unit 22.

When the acquisition period has elapsed from time t5 and it becomes time t6, the microcomputer 1 acquires the closed circuit voltage of the battery cell 7 detected by the monitoring IC 3 in the entire range. Of course, at this time, it is expected that the output voltage of the battery pack 5 has reached the target voltage. Therefore, the closed circuit voltage may be detected in a voltage measurement range based on this target voltage.

Seventh Embodiment
The seventh embodiment will be described with reference to FIG.

In the sixth embodiment, as described based on FIG. 10, when switching from a non-driven state to a driven state, the microcomputer 1 acquires the closed circuit voltage detected by the monitoring IC 3 over the entire range.

In contrast, in this embodiment, when switching from a non-driven state to a driven state, the microcomputer 1 acquires the closed circuit voltage detected by the monitoring IC 3 within the usable range of the battery cell 7. This makes it possible to improve the detection accuracy of the closed circuit voltage even when the battery management device 100 switches from a non-driven state to a driven state.

For example, at time t0 shown in FIG. 11, the battery management device 100 changes from a non-driven state to a driven state. The system main relay 6 changes from a disconnected state to a conductive state. Current starts to flow to the battery pack 5. The rate of decrease in the SOC and closed circuit voltage of the battery cell 7 increases.

When the time changes from t0 to t1, the microcomputer 1 sets a limited measurement range based on the characteristic data of SOC and OCV shown in FIG. 6. For example, the microcomputer 1 sets the usable range of the battery cell 7 between SOC1 and SOC2 shown in FIG. 6. The microcomputer 1 then sets the limited measurement range based on OCV1 and OCV2 corresponding to SOC1 and SOC2. As shown in FIG. 11, the microcomputer 1 sets the lower limit of the limited measurement range to CCV1 and the upper limit to CCV2.

The characteristic data shown in FIG. 6 depends on temperature. There is a difference in voltage drop between the open circuit voltage and the closed circuit voltage. For this reason, the microcomputer 1 may set a limited measurement range by taking into account not only the characteristic data shown in FIG. 6, but also the temperature, current, and degree of deterioration of the battery cell 7 at time t1.

To clearly distinguish this from the full range described in other embodiments, in this embodiment, as described above, the microcomputer 1 sets the voltage measurement range at time t1 to the limited measurement range. However, the battery cell 7 is used within the usable range to begin with. Therefore, it is expected that the closed circuit voltage detected will be within this usable range. Therefore, the usable range may be set to the full range to begin with. Such a setting can also be applied to other embodiments and modified examples.

Eighth embodiment
The eighth embodiment will be described with reference to FIG.

In the above embodiments, the microcomputer 1 acquires the closed circuit voltage of each of the plurality of battery cells 7 regardless of whether the equalization process is performed. In contrast, in the present embodiment, the microcomputer 1 acquires the closed circuit voltage of a portion of the plurality of battery cells 7 after the equalization process is performed.

When the equalization process is performed, the SOC of each of the multiple battery cells 7 is equalized. For this reason, it is expected that the closed circuit voltage of each of the multiple battery cells 7 will be equivalent. Therefore, after the equalization process is performed, the monitoring IC 3 detects the closed circuit voltage of some of the multiple battery cells 7. The microcomputer 1 acquires the closed circuit voltage detected by the monitoring IC 3. This simplifies the calculation process of the monitoring IC 3 and the microcomputer 1.

The monitoring IC 3 may detect all of the closed circuit voltages of the multiple battery cells 7. The microcomputer 1 may then acquire some of the multiple closed circuit voltages detected by the monitoring IC 3. This simplifies the calculation process of the microcomputer 1.

However, after a certain amount of time has passed since equalization was performed, the SOCs of the multiple battery cells 7 will vary. The closed circuit voltages of the multiple battery cells 7 will become unequal.

The microcomputer 1 then executes the acquisition target setting process shown in FIG. 12. The microcomputer 1 executes this acquisition target setting process as a cycle task. The microcomputer 1 executes this acquisition target setting process in parallel with other processes, such as the battery management shown in FIG. 4 or FIG. 10.

In step S310, the microcomputer 1 determines whether the equalization counter held by the microcomputer 1 is smaller than the expected variation value stored in the memory unit 22. If it is determined that the equalization counter is smaller than the expected variation value, the microcomputer 1 proceeds to step S320. If it is determined that the equalization counter is equal to or greater than the expected variation value, the microcomputer 1 proceeds to step S330.

The value of the equalization counter is cleared when the equalization process is performed. The predicted variation value is determined based on the time it is expected that the closed circuit voltages of the multiple battery cells 7 will become unequal after the equalization process is performed.

When the process proceeds to step S320, the microcomputer 1 increments the equalization counter. The microcomputer 1 then proceeds to step S340.

When the process proceeds to step S340, the microcomputer 1 sets only some of the multiple battery cells 7 for which the equalization process has been performed as the targets for obtaining the closed circuit voltage (voltage measurement targets). For example, the microcomputer 1 sets one of the multiple battery cells 7 included in one battery group as the target for obtaining the closed circuit voltage. For example, the microcomputer 1 sets one of all the battery cells 7 included in the multiple battery groups as the target for obtaining the closed circuit voltage. The microcomputer 1 then ends the acquisition target setting process.

When it is determined in step S310 that the equalization counter is equal to or greater than the expected variation value and the process proceeds to step S330, the microcomputer 1 sets all of the multiple battery cells 7 as targets for obtaining the closed circuit voltage. After this, the microcomputer 1 ends the acquisition target setting process.

After the equalization process is performed, the microcomputer 1 repeatedly executes steps S310, S320, and S340. During this time, only the closed circuit voltages of some of the battery cells 7 for which the equalization process has been performed are set as targets for acquisition.

After this, when the equalization counter reaches the expected variation value, the microcomputer 1 repeatedly executes step S330. After this, all of the closed circuit voltages of the multiple battery cells 7 are set as acquisition targets until the equalization process is executed again.

<Other embodiments>
The disclosure of this specification is not limited to the exemplified embodiments. The disclosure includes the exemplified embodiments and modifications made by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which parts and elements of the embodiments are omitted. The disclosure includes the replacement or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is indicated by the description of the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the description of the claims.

(Other Modifications)
The battery management device 100 capable of achieving the object disclosed in the specification is not limited to a configuration in which each battery group has a monitoring IC 3. The battery management device 100 may have a configuration in which a monitoring IC 3 and a microcomputer 1 are provided for each battery pack 5. The battery management device 100 may have a configuration in which one microcomputer 1 is provided for each battery group.

1...Microcomputer (range setting section, equalization judgment section, SOC estimation section, SOH estimation section), 3...Monitoring IC (measurement section), 5...Battery pack, 7...Battery cell, 12...Charging equipment (external power source), 100...Battery management device, 200...Battery device

Claims (16)

A range setting unit (1) that sets a limited measurement range that limits a voltage measurement range for a plurality of in-vehicle batteries (7);
a measurement unit (3; 103) that measures the voltage of the battery within the limited measurement range set by the range setting unit ;
The range setting unit sets a limited measurement range based on the voltage of the battery measured by the measurement unit so as to include that voltage . The battery management device according to claim 1, wherein the measurement unit adjusts the voltage measurement range in response to a command output from the range setting unit to set the limited measurement range. The range setting unit is
If the voltage value of the battery is known, the limited measurement range is adjusted based on the voltage value of the battery;
3. The battery management device according to claim 1, wherein when the voltage value of the battery is unknown, the limited measurement range is set based on voltage measurements performed over the entire range of voltages. The battery management device according to claim 3, wherein the range setting unit sets the limited measurement range using at least one of the maximum and minimum voltage measurement values measured over the entire range of voltage. The battery management device according to any one of claims 1 to 4, wherein the range setting unit is configured to set a plurality of different limited measurement ranges. The battery management device according to any one of claims 1 to 5, wherein the range setting unit sets the limited measurement range when the noise level is acceptable in a noise-acceptable situation, and the measurement unit measures the voltage of the battery within the limited measurement range. The battery management device according to claim 6, wherein the range setting unit sets the limited measurement range and the measurement unit measures the voltage of the battery within the limited measurement range when a power device that provides driving force for the vehicle is in a stopped state and charging/discharging of the battery is stopped. A battery management device according to any one of claims 1 to 5, in which, when the battery is being charged from an external power source (12), the charging is temporarily stopped, and the range setting unit sets the limited measurement range, and the measurement unit measures the voltage of the battery within the limited measurement range. an equalization determination unit (1) that determines whether or not to perform an equalization process for reducing voltage variations for a predetermined battery group including at least a portion of the plurality of batteries;
The battery management device according to claim 1 , wherein the equalization determination unit determines whether or not to perform the equalization process based on a voltage measurement value of the battery measured in the limited measurement range. an equalization determination unit (1) that determines whether or not to perform an equalization process for reducing voltage variations for a predetermined battery group including at least a portion of the plurality of batteries;
the equalization determination unit sets a determination threshold in accordance with a width of the limited measurement range set by the range setting unit;
The battery management device according to any one of claims 1 to 8, wherein the equalization determination unit determines not to perform the equalization process when the difference between the maximum voltage measurement value and the minimum voltage measurement value measured for a specific battery group including at least a portion of the multiple batteries is smaller than the determination threshold, and determines to perform the equalization process when the difference is larger than the determination threshold. The battery management device according to claim 10, wherein the equalization determination unit corrects the judgment threshold to a larger value when the width of the limited measurement range set by the range setting unit is larger than a predetermined range width, and corrects the judgment threshold to a smaller value when the width of the limited measurement range is smaller than the predetermined range width. The battery management device according to any one of claims 9 to 11, wherein the equalization determination unit, when the equalization process is performed on the batteries included in the battery group, targets some of the batteries included in the battery group for voltage measurement. The battery management device according to any one of claims 1 to 12, further comprising an SOC estimation unit (1) that estimates the charge rate based on characteristic data indicating the relationship between the open circuit voltage and charge rate of the battery and the voltage measurement value of the battery measured in the limited measurement range. The battery management device according to claim 13, further comprising a SOH estimation unit (1) that estimates the SOH, which indicates the degree of deterioration of the battery, using the charge rate estimated by the SOC estimation unit. The battery management device according to any one of claims 1 to 14, wherein the range setting unit sets the voltage measurement range to a usable range of the battery when switching from a non-driven state to a driven state. A plurality of batteries (7) for mounting on a vehicle;
A range setting unit (1) that sets a limited measurement range that limits a voltage measurement range for the battery;
a measurement unit (3; 103) that measures the voltage of the battery within the limited measurement range set by the range setting unit ;
The range setting unit sets a limited measurement range based on the voltage of the battery measured by the measurement unit so as to include that voltage .

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