JP7151079B2 - Battery state estimation device and power supply device - Google Patents

Description

The present invention relates to a battery state estimation device and a power supply device.

Conventionally, the state of charge (SOC) is estimated in a battery module including a plurality of secondary batteries. In Patent Document 1, the polarization voltage during charging and discharging of the secondary battery is estimated from the charging and discharging current flowing in the secondary battery and the temperature of the secondary battery, and the battery voltage of the secondary battery and the estimated polarization voltage are calculated. A configuration for estimating the SOC by obtaining the electromotive force of the secondary battery is disclosed. With such a configuration, the temperature is taken into account in estimating the polarization voltage of the secondary battery, so it is possible to estimate the SOC with high accuracy.

JP 2008-243373 A

However, in PHVs (Plug-in Hybrid Vehicles) and EVs (Electric Vehicles), the number of secondary batteries constituting a battery module is extremely large, so that the battery characteristics of the secondary batteries tend to vary. If the configuration disclosed in Patent Document 1 is applied to estimate the battery state of such a battery module with high accuracy, it is necessary to perform calculations for each secondary battery in consideration of variations in battery characteristics of the secondary batteries. As a result, in a battery module having a large number of secondary batteries, the calculation load becomes large, causing problems such as an increase in power consumption and heat generation in the calculation unit.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery state estimating device capable of estimating the battery state of a battery module having a large number of secondary batteries with low power consumption and high accuracy.

One aspect of the present invention is a battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
A battery configured to be able to change the number of targets, which is the number of the secondary batteries for which the battery state of the secondary battery is estimated, based on the specific values obtained from the plurality of secondary batteries. in the state estimator.
Another aspect of the present invention is a battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries for which the battery state of the secondary batteries is estimated, can be changed, or The calculation formula for estimating the battery state of the battery is configured to be changeable to a calculation formula with less calculation load,
The specific value is in the battery state estimating device, which is calculated based on the SOC, which is the state of charge of the secondary battery.
Still another aspect of the present invention is a battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries for which the battery state of the secondary batteries is estimated, can be changed, or The calculation formula for estimating the battery state of the battery is configured to be changeable to a calculation formula with less calculation load,
The specific value is in the battery state estimating device, which is calculated based on the SOC, which is the state of charge of the secondary battery.

The battery state estimating device is configured to be able to change the number of targets for estimating the battery state of a plurality of secondary batteries, or to calculate an arithmetic expression for the estimation, based on the specific value obtained from the secondary battery. It is configured so that it can be changed to an arithmetic expression with less load. As a result, control can be performed so as to reduce the power consumed for the calculation while maintaining the calculation accuracy.

As described above, according to the present invention, it is possible to provide a battery state estimation device capable of estimating the battery state of a battery module having a large number of secondary batteries with low power consumption and high accuracy.

It should be noted that the symbols in parentheses described in the claims and the means for solving the problems indicate the corresponding relationship with the specific means described in the embodiments described later, and limit the technical scope of the present invention. not a thing

1 is a block diagram showing the configuration of a battery state estimation device according to Embodiment 1. FIG. 4 is a conceptual diagram showing the relationship between the temperature difference threshold and the temperature in the first embodiment; FIG. 4 is a flow diagram showing a control mode of the battery state estimation device in the first embodiment; FIG. The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 2. FIG. FIG. 10 is a flow diagram showing a control mode of the battery state estimation device according to the second embodiment; The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 3. FIG. FIG. 10 is a flow diagram showing a control mode of the battery state estimation device according to the third embodiment; The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 4. FIG. The flowchart which shows the control aspect of the battery state estimation apparatus in Embodiment 4. FIG. The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 5. FIG. FIG. 12 is a conceptual diagram showing the relationship between the SOC and the SOC difference threshold in Embodiment 5; FIG. 11 is a conceptual diagram showing the relationship between temperature and SOC difference threshold in Embodiment 5; FIG. 12 is a flowchart showing a control mode of the battery state estimation device in Embodiment 5; The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 6. FIG. The flow chart which shows the control aspect of the battery state estimation apparatus in Embodiment 6. FIG. The block diagram which shows the structure of the battery state estimation apparatus in Embodiment 7. FIG. FIG. 11 is a conceptual diagram showing an SOC-OCV curve in Embodiment 7; FIG. 11 is a conceptual diagram showing the relationship between temperature and slope threshold in Embodiment 7; The flowchart which shows the control aspect of the battery state estimation apparatus in Embodiment 7. FIG. FIG. 11 is a block diagram showing the configuration of a battery state estimation device according to an eighth embodiment; FIG. 12 is a flow diagram showing a control mode of the battery state estimation device according to the eighth embodiment;

(Embodiment 1)
An embodiment of the battery state estimation device will be described with reference to FIGS. 1 to 3. FIG.
As shown in FIG. 1 , the battery state estimation device 1 of this embodiment estimates the battery state in a battery module 10 having a plurality of secondary batteries 2 . The battery state estimating device 1 is configured to be able to change the amount of calculation for estimating the battery state of the secondary battery 2 based on the specific values acquired from the plurality of secondary batteries 2 .

Hereinafter, the battery state estimation device 1 of this embodiment will be described in detail.
A battery state estimation device 1 shown in FIG. 1 estimates the battery state of a secondary battery 2 mounted in a battery control unit in a vehicle such as an electric vehicle. A plurality of secondary batteries 2 are provided to form a battery module 10 . In this embodiment, the battery module 10 is equipped with ten secondary batteries 2 . The battery module 10 may have a configuration including a plurality of cell blocks composed of a plurality of secondary batteries. A power supply device 100 is composed of the battery module 10 and the battery state estimation device 1 .

As shown in FIG. 1 , the battery state estimation device 1 has an acquisition unit 3 , a storage unit 4 , a storage unit 5 and a calculation unit 6 . The acquisition unit 3 has a temperature acquisition unit 30 that acquires temperatures of the plurality of secondary batteries 2 . A temperature acquisition unit 30 is composed of a temperature sensor, is connected to the secondary battery 2 , and detects the temperature of the secondary battery 2 . The timing of obtaining the temperature is not particularly limited, and the temperature may be obtained all the time or at predetermined intervals. When the battery module 10 has a plurality of cell blocks each composed of a plurality of secondary batteries 2, the temperature acquisition unit 30 detects the temperature of the cell block detected by the temperature sensor provided for each cell block. It may be obtained as

As shown in FIG. 1 , the storage unit 4 has a temperature storage unit 40 and a temperature difference storage unit 41 . The temperature storage unit 40 is composed of a rewritable non-volatile memory, and stores the temperatures of the plurality of secondary batteries 2 acquired by the temperature acquisition unit 30 . The temperature difference storage unit 41 is also composed of a rewritable non-volatile memory, and stores the temperature difference calculated by the temperature difference calculation unit 60, which will be described later.

As shown in FIG. 1 , the storage unit 5 has a temperature difference threshold storage unit 50 . The temperature difference threshold storage unit 50 is composed of a non-rewritable non-volatile memory, and stores at least one temperature difference threshold in advance. When multiple temperature difference thresholds are stored, the multiple temperature difference thresholds may form a predetermined relational expression or map. In this embodiment, as shown in FIG. 2 , the temperature difference threshold storage unit 50 stores a plurality of temperature difference thresholds in a map defined by the temperature of the secondary battery 2 .

As shown in FIG. 1 , the calculation unit 6 has a temperature difference calculation unit 60 , a temperature difference comparison unit 61 , a target number setting unit 62 , a target determination unit 63 and a battery state estimation unit 64 . The calculation unit 6 is configured to be able to execute programs that function as a temperature difference calculation unit 60 , a temperature difference comparison unit 61 , a target number setting unit 62 , a target determination unit 63 and a battery state estimation unit 64 . The program is stored in a memory (not shown) provided in the computing unit 6 .

The temperature difference calculator 60 calculates temperature differences among the plurality of secondary batteries 2 as specific values. In this embodiment, the temperature difference is the difference between the maximum and minimum temperatures of the plurality of secondary batteries 2 at predetermined timings stored in the temperature storage unit 40 . Note that when the battery module 10 has a plurality of cell blocks composed of a plurality of secondary batteries 2, the temperature difference in the temperature of the cell blocks stored in the temperature storage unit 40 is the temperature difference in the plurality of secondary batteries 2. can be calculated as The calculated temperature difference is stored in the temperature difference storage unit 41 .

The temperature difference comparison unit 61 shown in FIG. 1 extracts the temperature difference stored in the temperature difference storage unit 41, extracts the temperature difference threshold stored in the temperature difference threshold storage unit 50, and compares the two. Extraction of the temperature difference threshold in the temperature difference threshold storage unit 50 can be performed based on the temperature stored in the temperature storage unit 40. In this embodiment, for example, the temperature difference threshold storage unit 50 stores the temperature shown in FIG. When the difference thresholds form a map, the predetermined temperature difference thresholds can be extracted from the temperatures stored in the temperature storage unit 40 . Then, the temperature difference comparison unit 61 compares the extracted temperature difference threshold with the temperature difference stored in the temperature difference storage unit 41 . In this embodiment, the temperature difference comparison unit 61 compares the temperature difference extracted from the temperature storage unit 40 with the temperature difference threshold, and indicates the magnitude relationship between the temperature difference and the temperature difference threshold as a comparison result.

The number-of-targets setting unit 62 shown in FIG. 1 sets the number of targets, which is the number of secondary batteries 2, estimated by the battery state estimating unit 64 described later, based on the comparison result of the temperature difference comparing unit 61 . In this embodiment, when the comparison result of the temperature difference comparison unit 61 indicates that the temperature difference is smaller than the temperature difference threshold, the target number setting unit 62 reduces the number of targets. On the other hand, when the comparison result of the temperature difference comparing section 61 indicates that the temperature difference is not smaller than the temperature difference threshold, the target number setting section 62 does not reduce the target number and maintains the current target number.

Based on the target number set by the target number setting section 62, the target determination section 63 determines the secondary battery 2 to be the estimation target. For example, the estimation target can be determined as follows. Among the plurality of secondary batteries 2, those with poor battery characteristics can be extracted and used as estimation targets, and those with good battery characteristics can be excluded. For example, from among all the secondary batteries 2, those with low temperatures acquired by the temperature acquisition unit 30, those with high input/output resistance, those with remaining battery power that is far from the median value, etc. are extracted and used as estimation targets. , and others can be excluded.

After that, the battery state estimation unit 64 estimates the battery state of the secondary battery 2 that is the target of estimation determined by the target determination unit 63 . The battery state estimated by the battery state estimation unit 64 is not particularly limited, and the state of charge (SOC), input/output power, chargeable/dischargeable power amount, input/output resistance, etc. of the secondary battery 2 can be estimated.

Next, the mode of use of the battery state estimation device 1 will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 3, the temperature of the secondary battery 2 is obtained by the temperature obtaining unit 30 in step S1. Then, the acquired temperature is stored in the temperature storage unit 40 . In this embodiment, the temperature acquisition unit 30 constantly acquires the temperature flowing through the secondary battery 2 . Then, in step S<b>2 , the temperature difference calculation unit 60 calculates the temperature difference, which is the difference between the highest temperature and the lowest temperature, from the temperatures of all the secondary batteries 2 stored in the temperature storage unit 40 . Then, the calculated temperature difference is stored in the temperature difference storage unit 41 .

Thereafter, as shown in FIG. 3, in step S3, first, the temperature difference stored in the temperature difference storage unit 41 is extracted by the temperature difference comparison unit 61, and the temperature difference stored in the temperature difference threshold storage unit 50 is extracted. Extract the threshold. In this embodiment, the temperature difference threshold is extracted from the temperature difference threshold map shown in FIG. 2 based on the temperature stored in the temperature storage unit 40 . Then, the extracted temperature difference and the temperature difference threshold are compared. The temperature difference comparison unit 61 indicates the magnitude relationship between the temperature difference and the temperature difference threshold value as a comparison result.

Then, in step S3, when the comparison result of the temperature difference comparison unit 61 indicates that the temperature difference is smaller than the temperature difference threshold, the process proceeds to Yes in step S3, and in step S4, the target number setting unit 62 Reduce the number of targets. On the other hand, if the comparison result of the temperature difference comparison unit 61 in step S3 indicates that the temperature difference is not smaller than the temperature difference threshold, the process proceeds to No in step S3, and in step S5, the target number setting unit 62 The number of targets is not reduced, and the number of targets is used as the initial value.

Then, after step S4 or step S5, in step S6, the target determination unit 63 determines the secondary battery 2 to be an estimation target. In the present embodiment, the target determining unit 63 selects the secondary battery 2 having a low temperature as the estimation target after step S4 is performed. On the other hand, after execution of step S5, all secondary batteries 2 are subject to estimation. After that, in step S7, the battery state estimating unit 64 estimates the battery state of the secondary battery 2 set as the estimation target by the target determining unit 63, and this control ends.

Next, the effects of the battery state estimation device 1 of this embodiment will be described in detail.
According to the battery state estimating device 1 , the number of targets for estimating the battery states of the plurality of secondary batteries 2 can be changed based on the specific value acquired from the secondary batteries 2 . As a result, it is possible to control so as to reduce the power consumed for the calculation while maintaining the calculation accuracy.

Further, in this embodiment, the specific value is calculated based on the temperature of the secondary battery 2 . As a result, the specific value reliably reflects the battery state of the secondary battery 2 , so the amount of calculation can be appropriately changed according to the battery state of the secondary battery 2 . As a result, the power consumption of the calculation is reduced while maintaining the calculation accuracy.

Further, in the present embodiment, the temperature acquisition unit 30 acquires the temperatures of at least two secondary batteries 2, and the temperature difference calculation unit 60 calculates the temperature difference between the at least two temperatures acquired by the temperature acquisition unit 30 as the specific value. a temperature difference comparison unit 61 that compares the temperature difference calculated by the temperature difference calculation unit 60 with a preset temperature difference threshold; A target number setting unit 62 that sets the number of targets, which is the number of secondary batteries 2 that become a portion 64; As a result, even if the battery module 10 has a large number of secondary batteries 2, the estimation target is set after setting the number of targets in consideration of the temperature of the secondary battery 2. Control can be performed to reduce power consumption for calculation while maintaining accuracy.

Further, in the present embodiment, the target number setting unit 62 reduces the number of targets when the comparison result of the temperature difference comparison unit 61 indicates that the temperature difference calculated by the temperature difference calculation unit 60 is smaller than the temperature difference threshold. . When the temperature variation among the plurality of secondary batteries 2 is small, the battery state variation among the secondary batteries 2 is also small. Therefore, in the battery module 10 including the plurality of secondary batteries 2, by reducing the battery state estimation target when the temperature difference is smaller than the temperature difference threshold, the estimation accuracy is maintained and the amount of calculation is reduced. Power consumption can be reduced.

Further, in the present embodiment, the temperature difference threshold storage unit 50 in which a plurality of temperature difference thresholds are stored in advance is provided, and the temperature difference comparison unit 61 selects the temperature based on one of the at least two temperatures acquired by the temperature acquisition unit 30. Then, the temperature difference threshold is extracted from the temperature difference threshold storage unit 50, and the extracted temperature difference threshold and the temperature difference calculated by the temperature difference calculation unit 60 are compared. The rate at which the battery state of the secondary battery 2 changes depends on the temperature. Therefore, the degree of variation in the battery states of the plurality of secondary batteries 2 also differs depending on the temperature of each secondary battery 2 . Therefore, in the present embodiment, with the configuration as described above, the temperature difference threshold for comparison with the temperature difference in the plurality of secondary batteries 2 also takes into account the temperature of the secondary batteries 2. A temperature difference threshold corresponding to the variation can be extracted. As a result, when the variation in the battery state of the secondary battery 2 is small, it is possible to reduce the number of battery state estimation targets, thereby reducing the amount of calculation and power consumption while maintaining the estimation accuracy.

Further, in the present embodiment, the power supply device 100 includes the battery state estimation device 1 described above, and a battery module having ten or more secondary batteries 2 whose battery states are estimated by the battery state estimation device 1. 10; Since the power supply device 100 has a large number of secondary batteries 2, by estimating the battery state by the battery state estimating device 1, while maintaining the estimation accuracy, the amount of calculation is greatly reduced, and the power consumption is greatly reduced. can be reduced.

As described above, according to the present embodiment, it is possible to provide the battery state estimation device 1 capable of estimating the battery state of the battery module 10 having a large number of secondary batteries 2 with low power consumption and high accuracy.

(Embodiment 2)
In the battery state estimation device 1 of Embodiment 2, in addition to the configuration of Embodiment 1 shown in FIG. 1, as shown in FIG. Storage unit 42 and voltage difference storage unit 43 , storage unit 5 has voltage difference threshold storage unit 51 , calculation unit 6 includes voltage difference calculation unit 65 , voltage difference comparison unit 66 and change determination unit 67 . have. Other components are the same as in the first embodiment, and the same reference numerals as in the first embodiment are used in the present embodiment, and the description thereof is omitted.

The voltage value acquisition unit 31 shown in FIG. 4 is configured to acquire the terminal voltage of the secondary battery 2 . The voltage value storage unit 42 is composed of a rewritable non-volatile memory, and stores the voltage value acquired by the voltage value acquisition unit 31 .

A voltage difference calculator 65 shown in FIG. 4 calculates the voltage difference between the terminal voltages of the plurality of secondary batteries 2 . The voltage difference is the difference between the maximum and minimum terminal voltages of the plurality of secondary batteries 2 at the predetermined timing stored in the voltage value storage unit 42 . The calculated voltage difference is stored in the voltage difference storage unit 43 . When the battery module 10 has a plurality of cell blocks composed of a plurality of secondary batteries 2, the voltage difference in the cell blocks stored in the voltage difference storage unit 43 is calculated as the voltage difference in the plurality of secondary batteries 2. be able to.

The voltage difference threshold storage unit 51 shown in FIG. 4 stores in advance a voltage difference threshold as a reference value of the voltage value used in the change determination unit 67, which will be described later. The voltage difference threshold can be appropriately set according to the configuration of the secondary battery 2 that can be an estimation target.

The voltage difference comparator 66 shown in FIG. 4 compares the voltage difference calculated by the voltage difference calculator 65 with a preset voltage difference threshold. In this embodiment, the voltage difference comparison unit 66 compares the voltage difference extracted from the voltage difference storage unit 43 and the voltage difference threshold value extracted from the voltage difference threshold storage unit 51, and compares the voltage difference and the voltage difference as a comparison result. It shows the magnitude relationship with the difference threshold.

A change determination unit 67 shown in FIG. 4 determines whether or not to change the number of targets based on the comparison result of the voltage difference comparison unit 66 . In this embodiment, if the voltage difference is greater than the voltage difference threshold, it is determined to change the number of targets, otherwise it is determined not to change the number of targets. Then, the number-of-targets setting unit 62 changes the number of targets based on the determination result of the change determination unit 67 .

Next, the mode of use of the battery state estimation device 1 according to Embodiment 2 will be described with reference to the flowchart shown in FIG. First, steps S1 to S4 are performed as shown in FIG. 5 in the same manner as in the first embodiment shown in FIG. As shown in FIG. 5, in step S10 after step S4, the voltage value acquiring unit 31 acquires the terminal voltages of all the secondary batteries 2 and stores them in the voltage value storage unit 42. FIG. Then, in step S11, the voltage difference calculation unit 65 calculates the voltage difference, which is the difference between the highest voltage value and the lowest voltage value, from the voltage values of all the secondary batteries 2 stored in the voltage value storage unit 42. and stored in the voltage difference storage unit 43 .

After that, in step S12, the voltage difference comparison unit 66 extracts the voltage difference stored in the voltage difference storage unit 43 and the voltage difference threshold value stored in the voltage difference threshold storage unit 51, and compares them. Then, the voltage difference comparison unit 66 indicates the magnitude relationship between the voltage difference and the voltage difference threshold value as a comparison result.

Then, in step S12, if the comparison result of the voltage difference comparison unit 66 indicates that the voltage difference is greater than the voltage difference threshold, the process proceeds to Yes in step S12, and in step S5, the reduced number of targets is returned to the initial value. , perform steps S6 and S7. On the other hand, in step S12, if the comparison result of the voltage difference comparison unit 66 indicates that the voltage difference is not greater than the voltage difference threshold, the process proceeds to No in step S12, and steps S6 and S7 are performed without changing the number of targets. to implement.

According to the battery state estimating device 1 of the second embodiment, when the terminal voltage variation of the secondary batteries 2 is excessively large, the number of objects to be estimated is returned to the initial value, that is, all the secondary batteries 2 . As a result, when the variation in the terminal voltage of the secondary battery 2 is excessively large, the change in the state of the secondary battery 2 is large. Although the number of targets is returned to the initial value in this embodiment, the number of targets may be increased to a predetermined number without being limited to this. Also in this embodiment, the same effect as the effect in Embodiment 1 is produced.

(Embodiment 3)
In the battery state estimation device 1 of the third embodiment, the temperature difference storage unit 41, the temperature difference threshold storage unit 50, the temperature difference calculation unit 60, the temperature difference comparison unit 61, the target number setting unit 62, and the temperature difference storage unit 41 of the first embodiment shown in FIG. Instead of the target determination unit 63, a temperature threshold storage unit 500, an arithmetic expression storage unit 510, a temperature comparison unit 610, and an arithmetic expression setting unit 620 are provided as shown in FIG. In this embodiment, the temperature acquisition unit 30 acquires the temperature of the secondary battery 2 as the specific value and stores the acquired temperature in the temperature storage unit 40 . Other components are the same as in the first embodiment, and the same reference numerals as in the first embodiment are used in the present embodiment, and the description thereof is omitted.

Temperature thresholds are stored in advance in the temperature threshold storage unit 500 shown in FIG. The temperature threshold can be appropriately set based on the configuration of the secondary battery 2 and the like. For example, the temperature threshold can be set at 25° C. in consideration of changes in input/output resistance of the secondary battery 2 .

A temperature comparison unit 610 shown in FIG. 6 compares the temperature acquired by the temperature acquisition unit 30 with a preset temperature threshold. The temperature acquired by the temperature acquisition unit 30 is extracted from the temperature storage unit 40 . Also, the temperature threshold is extracted from the temperature threshold storage unit 500 . The temperature comparison unit 610 indicates the magnitude relationship between the temperature and the temperature threshold as a comparison result.

The arithmetic expression storage unit 510 stores an arithmetic expression used by the battery state estimating unit 64 to estimate the battery state. The form of the arithmetic expression stored in the arithmetic expression storage unit 510 is not particularly limited, and may be in the form of a relational expression, function, or map for estimating the battery state. A plurality of arithmetic expressions with different arithmetic loads are stored in the arithmetic expression storage unit 510 . Examples of the computational formula include a theoretical formula with a heavy computational load based on a theoretical model, an approximation formula in which a part or all of the theoretical formula is approximately represented by a function with a low computational load, or a specific condition from the theoretical formula. A map with less computational load derived in .

Operational expression setting section 620 sets an operational expression for estimating the battery state based on the comparison result of temperature comparison section 610 . The arithmetic expression is extracted from the arithmetic expression storage unit 510 by the arithmetic expression setting unit 620 . For example, when the comparison result of the temperature comparison unit 610 indicates that the temperature is higher than the temperature threshold, the arithmetic expression setting unit 620 extracts an arithmetic expression with a small arithmetic load from the arithmetic expression storage unit 510, and determines the battery state. Set as an arithmetic expression for estimation. When the comparison result of the temperature comparison unit 610 indicates that the temperature is not greater than the temperature threshold, the arithmetic expression setting unit 620 extracts an arithmetic expression with a not small arithmetic load from the arithmetic expression storage unit 510, and determines the battery state. Set as an arithmetic expression for estimation.

Next, the mode of use of the battery state estimation device 1 of this embodiment will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 7, in step S31, the temperature acquisition unit 30 acquires the temperatures of all the secondary batteries 2 as specific values. Then, the acquired temperature is stored in the temperature storage unit 40 . In this embodiment, the temperature acquisition unit 30 constantly acquires the temperature flowing through the secondary battery 2 .

Then, in step S<b>32 , the temperature comparison unit 610 first extracts the temperature stored in the temperature storage unit 40 and extracts the temperature threshold stored in the temperature threshold storage unit 500 . Then, the temperature comparison unit 610 compares the extracted temperature and the temperature threshold, and indicates the magnitude relationship between the extracted temperature and the temperature threshold as a comparison result.

Then, in step S32, if the comparison result of the temperature comparison unit 610 indicates that the extracted temperature is higher than the temperature threshold, the process proceeds to Yes in step S32, and in step S33, the arithmetic expression setting unit 620 An arithmetic expression with a low computational load is extracted from the arithmetic expression storage unit 510 and set as an arithmetic expression for estimating the battery state.

On the other hand, in step S32, if the comparison result of the temperature comparison unit 610 indicates that the extracted temperature is not greater than the temperature threshold, the process proceeds to No in step S32, and in step S34, the arithmetic expression setting unit 620 , an arithmetic expression in the initial state is extracted from the arithmetic expression storage unit 510 and set as an arithmetic expression for estimating the battery state. Note that the computational expression in the initial state has a relatively large computational load.

Then, after steps S33 and S34, in step S35, the battery state estimating unit 64 estimates the battery states of all the secondary batteries 2 based on the set arithmetic expression, and ends this control.

The effects of the battery state estimation device 1 of this embodiment will be described in detail below.
When the temperature of the secondary battery 2 is high, the input/output resistance of the secondary battery 2 becomes relatively small, and the change in state of the secondary battery is small. Therefore, according to the battery state estimating device 1 of the present embodiment, when the temperature of the secondary battery 2 as a specific value is higher than the temperature threshold, the battery state is estimated using an arithmetic expression with a small computational load. . As a result, by using an arithmetic expression with a small arithmetic load when the battery state changes little, power consumption can be reduced while suppressing deterioration in estimation accuracy and maintaining estimation accuracy.

(Embodiment 4)
In the battery state estimation device 1 of Embodiment 4, in addition to the configuration of Embodiment 3 shown in FIG. 6, as shown in FIG. It has a section 43 , a voltage difference threshold storage section 51 , a voltage difference calculation section 65 , a voltage difference comparison section 66 and a change determination section 67 . Other components are the same as those in the first, second and third embodiments, and the same reference numerals as those in the first, second and third embodiments are used in this embodiment, and descriptions thereof are omitted.

In this embodiment, instead of the case of the second embodiment, the change determination unit 67 shown in FIG. In this embodiment, if the voltage difference is greater than the voltage difference threshold, it is determined to change the setting of the arithmetic expression, otherwise it is determined not to change the setting of the arithmetic expression. Then, the arithmetic expression setting section 620 shown in FIG. 8 changes the number of targets based on the determination result of the change determination section 67 .

Next, the mode of use of the battery state estimation device 1 according to Embodiment 4 will be described with reference to the flowchart shown in FIG. First, as in the third embodiment shown in FIG. 7, steps S31 to S34 are performed as shown in FIG. After step S<b>33 , in step S<b>40 , the voltage value obtaining unit 31 obtains the terminal voltages of all the secondary batteries 2 and stores them in the voltage value storage unit 42 . Then, in step S41, the voltage difference calculation unit 65 calculates the voltage difference, which is the difference between the highest voltage value and the lowest voltage value, from the voltage values of all the secondary batteries 2 stored in the voltage value storage unit 42. It is calculated and stored in the voltage difference storage unit 43 .

Thereafter, in step S42 shown in FIG. 9, the voltage difference comparison unit 66 extracts the voltage difference stored in the voltage difference storage unit 43 and the voltage difference threshold value stored in the voltage difference threshold storage unit 51, and compares the two. . Then, the voltage difference comparison unit 66 indicates the magnitude relationship between the voltage difference and the voltage difference threshold value as a comparison result.

Then, in step S42 shown in FIG. 9, when the comparison result of the voltage difference comparison unit 66 indicates that the voltage difference is larger than the voltage difference threshold value, the process proceeds to Yes in step S42, and in step S34, the voltage set in step S33 is determined. A calculation formula with a low calculation load is changed to a calculation formula with a high calculation load in the initial state, and is set as the calculation formula used for estimating the battery state. After that, step S35 is executed and the control ends. On the other hand, if the comparison result of the voltage difference comparing section 66 indicates that the voltage difference is not greater than the voltage difference threshold in step S42, the process proceeds to No in step S42, executes step S35, and ends this control.

According to the battery state estimating device 1 of Embodiment 4, when the variation in the terminal voltage of the secondary battery 2 is excessively large, the arithmetic expression used for estimating the battery state is returned to the arithmetic expression with heavy arithmetic load in the initial state. As a result, when the variation in the terminal voltage of the secondary battery 2 is excessively large, the change in the state of the secondary battery 2 is large. can be done. Note that in the present embodiment, the arithmetic expression in the initial state is restored, but the present invention is not limited to this, and may be changed to an arithmetic expression with a higher calculation load as long as the arithmetic expression has high estimation accuracy. Also in this embodiment, the same effect as the effect in Embodiment 3 is produced.

(Embodiment 5)
In the battery state estimation device 1 of Embodiment 5, the temperature acquisition unit 30, the temperature storage unit 40, the temperature difference storage unit 41, the temperature difference threshold storage unit 50, the temperature difference calculation unit 60, and the temperature difference Instead of the comparison unit 61, as shown in FIG. 10, an SOC acquisition unit 530, an SOC storage unit 540, an SOC difference storage unit 541, an SOC difference threshold storage unit 550, an SOC difference calculation unit 560, and an SOC difference comparison unit 561 are provided. . Other components are the same as in the first embodiment, and the same reference numerals as in the first embodiment are used in the present embodiment, and the description thereof is omitted.

In this embodiment, as shown in FIG. 10, the SOC acquisition unit 530 acquires the state of charge of the secondary battery 2, that is, the SOC (State Of Charge) as the specific value. The SOC can be derived by obtaining the battery voltage of the secondary battery 2 based on an SOC-OCV curve showing the relationship between the SOC and the open-circuit voltage pre-stored in a storage unit (not shown). The timing of obtaining the SOC is not particularly limited, and it may be obtained all the time or at predetermined intervals. Note that when the battery module 10 has a plurality of cell blocks each composed of a plurality of secondary batteries 2, the SOC acquisition unit 530 acquires the SOC of the cell block detected for each cell block as the SOC of the secondary battery. may

As shown in FIG. 10 , the storage section 4 has an SOC storage section 540 and an SOC difference storage section 541 . The SOC storage unit 540 is composed of a rewritable nonvolatile memory, and stores the SOCs of the multiple secondary batteries 2 acquired by the SOC acquisition unit 530 . The SOC difference storage unit 541 is also composed of a rewritable non-volatile memory, and stores the SOC difference calculated by the SOC difference calculation unit 560, which will be described later.

As shown in FIG. 10 , the storage section 5 has an SOC difference threshold storage section 550 . The SOC difference threshold storage unit 550 is composed of a non-rewritable non-volatile memory, and stores at least one SOC difference threshold in advance. When multiple SOC difference thresholds are stored, the multiple SOC difference thresholds may form a predetermined relational expression or map. In the present embodiment, as shown in FIG. 11, the SOC difference threshold storage unit 550 stores a plurality of SOC difference thresholds in a map defined by the SOC of the secondary battery 2 . Note that the form of the map is not limited, and may be a form of a function between the SOC difference threshold and the SOC. Further, as shown in FIG. 12, a map in which a plurality of SOC difference thresholds are defined by the temperature of the secondary battery 2 may be constructed and stored.

As shown in FIG. 10 , the calculation unit 6 has an SOC difference calculation unit 560 , an SOC difference comparison unit 561 , a target number setting unit 62 , a target determination unit 63 and a battery state estimation unit 64 . The calculation unit 6 is configured to be able to execute programs that function as the SOC difference calculation unit 560 , the SOC difference comparison unit 561 , the target number setting unit 62 , the target determination unit 63 , and the battery state estimation unit 64 . The program is stored in a memory (not shown) provided in the computing unit 6 .

The SOC difference calculator 560 calculates SOC differences among the plurality of secondary batteries 2 as specific values. In the present embodiment, the SOC difference is the difference between the maximum and minimum SOCs of the plurality of secondary batteries 2 at predetermined timings stored in the SOC storage unit 540 . Note that when the battery module 10 has a plurality of cell blocks each including a plurality of secondary batteries 2, the SOC difference in the temperature of the cell blocks stored in the SOC storage unit 540 is calculated as the SOC difference in the plurality of secondary batteries 2. can be calculated as The calculated SOC difference is stored in the SOC difference storage unit 541 .

The SOC difference comparison unit 561 shown in FIG. 10 extracts the SOC difference stored in the SOC difference storage unit 541, extracts the SOC difference threshold stored in the SOC difference threshold storage unit 550, and compares the two. Extraction of the SOC difference threshold in the SOC difference threshold storage unit 550 can be performed based on the SOC stored in the SOC storage unit 540. is stored as a map based on SOC, a predetermined SOC difference threshold can be extracted from the SOC stored in the SOC storage unit 540 . Further, when the SOC difference threshold is stored as a map based on temperature as shown in FIG. 12, a predetermined SOC difference threshold can be extracted from the temperature of the secondary battery 2 detected by a temperature sensor (not shown).

Then, the SOC difference comparison section 561 compares the extracted SOC difference threshold with the SOC difference stored in the SOC difference storage section 541 . In the present embodiment, the SOC difference comparison unit 561 compares the SOC difference extracted from the SOC storage unit 540 with the SOC difference threshold, and indicates the magnitude relationship between the SOC difference and the SOC difference threshold as the comparison result.

The number-of-targets setting unit 62 shown in FIG. 10 sets the number of targets, which is the number of secondary batteries 2 estimated by the battery state estimating unit 64 , based on the comparison result of the SOC difference comparing unit 561 . In the present embodiment, when the comparison result of the SOC difference comparing section 561 indicates that the SOC difference is smaller than the SOC difference threshold, the number-of-targets setting section 62 reduces the number of targets. On the other hand, when the comparison result of the SOC difference comparing section 561 indicates that the SOC difference is not smaller than the SOC difference threshold, the target number setting section 62 does not reduce the target number and maintains the current target number.

Then, as in the case of the first embodiment, the target determination unit 63 determines the secondary batteries 2 to be estimated based on the number of targets set by the target number setting unit 62 . After that, the battery state estimating unit 64 estimates the battery state of the secondary battery 2 to be the estimation target determined by the target determining unit 63, as in the first embodiment. The battery state estimated by the battery state estimation unit 64 is not particularly limited, and the input/output power, chargeable/dischargeable power amount, input/output resistance, etc. of the secondary battery 2 can be estimated.

Next, the mode of use of the battery state estimation device 1 of this embodiment will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 13, the SOC of the secondary battery 2 is acquired by the SOC acquisition unit 530 in step S51. Then, the acquired SOC is stored in the SOC storage unit 540 . In this embodiment, the SOC obtaining unit 530 detects the current and the battery voltage of the secondary battery 2 to obtain the SOC. Then, in step S<b>52 , the SOC difference calculation unit 560 calculates the SOC difference, which is the difference between the highest SOC and the lowest SOC from the SOCs of all the secondary batteries 2 stored in the SOC storage unit 540 . Then, the calculated SOC difference is stored in the SOC difference storage unit 541 .

Thereafter, as shown in FIG. 13, in step S53, first, the SOC difference stored in the SOC difference storage unit 541 is extracted by the SOC difference comparison unit 561, and the SOC difference stored in the SOC difference threshold storage unit 550 is extracted. Extract the threshold. In this embodiment, the SOC difference threshold is extracted from the SOC difference threshold map shown in FIG. 12 based on the SOC stored in the SOC storage unit 540 . Then, the extracted SOC difference and the SOC difference threshold are compared. The SOC difference comparison unit 561 indicates the magnitude relationship between the SOC difference and the SOC difference threshold value as a comparison result.

Then, in step S53 shown in FIG. 13, when the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference is smaller than the SOC difference threshold, the process proceeds to Yes in step S53, and in step S54, the target number The setting unit 62 reduces the number of targets. On the other hand, if the comparison result of the SOC difference comparing unit 561 in step S53 indicates that the SOC difference is not smaller than the SOC difference threshold, the process proceeds to No in step S53, and in step S55, the target number setting unit 62 The number of targets is not reduced, and the number of targets is used as the initial value.

Then, after step S54 or step S55 shown in FIG. 13, in step S56, the target determining unit 63 determines the secondary battery 2 to be an estimation target. In the present embodiment, the target determining unit 63 selects the secondary battery 2 having a low SOC as the estimation target after step S54 is performed. On the other hand, after execution of step S55, all secondary batteries 2 are subject to estimation. After that, in step S57, the battery state estimating unit 64 estimates the battery state of the secondary battery 2 set as the estimation target by the target determining unit 63, and this control ends.

Next, the effects of the battery state estimation device 1 of this embodiment will be described in detail.
According to the battery state estimating device 1 , the number of targets for estimating the battery state of a plurality of secondary batteries 2 can be changed based on the SOC, which is the specific value acquired from the secondary battery 2 . As a result, it is possible to control so as to reduce the power consumed for the calculation while maintaining the calculation accuracy.

Further, in this embodiment, the specific value is calculated based on the SOC of the secondary battery 2 . As a result, the specific value reliably reflects the battery state of the secondary battery 2 , so the amount of calculation can be appropriately changed according to the battery state of the secondary battery 2 . As a result, it is possible to reduce power consumption for calculation while maintaining calculation accuracy, and to suppress heat generation.

In addition, in the present embodiment, an SOC acquisition unit 530 that acquires the SOCs of at least two secondary batteries 2 and an SOC difference calculation unit 560 that calculates the SOC difference between the at least two SOCs acquired by the SOC acquisition unit 530 as specific values. and an SOC difference comparison unit 561 that compares the SOC difference calculated by the SOC difference calculation unit 560 with a preset SOC difference threshold value, and the target for estimating the battery state based on the comparison result of the SOC difference comparison unit 561 A target number setting unit 62 that sets the number of targets, which is the number of secondary batteries 2 that become a portion 64; As a result, even when the battery module 10 has a large number of secondary batteries 2, the estimation target is set after setting the number of targets in consideration of the SOC of the secondary battery 2. Control can be performed to reduce power consumption for calculation while maintaining accuracy.

Further, in the present embodiment, the target number setting unit 62 reduces the number of targets when the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference calculated by the SOC difference calculation unit 560 is smaller than the SOC difference threshold. . When the SOC variation among the plurality of secondary batteries 2 is small, the battery state variation among the secondary batteries 2 is also small. Therefore, in the battery module 10 including the plurality of secondary batteries 2, when the SOC difference is smaller than the SOC difference threshold, the estimation accuracy is maintained and the amount of calculation is reduced by reducing the battery state estimation target. power consumption can be reduced.

In addition, in the present embodiment, the SOC difference threshold storage unit 550 in which a plurality of SOC difference threshold values are stored in advance is provided, and the SOC difference comparison unit 561 stores the SOC difference threshold based on the SOC acquired by the SOC acquisition unit 530 or the temperature of the secondary battery 2. An SOC difference threshold value is extracted from the SOC difference threshold storage unit 550, and the extracted SOC difference threshold value and the SOC difference calculated by the SOC difference calculation unit 560 are compared. As a result, the SOC difference threshold for comparison with the SOC difference in the plurality of secondary batteries 2 takes into consideration the SOC and temperature of the secondary batteries 2, so the SOC difference threshold corresponding to the variation in the battery state is extracted. can do. As a result, when the variation in the battery state of the secondary battery 2 is small, it is possible to reduce the number of battery state estimation targets, thereby reducing the amount of calculation and power consumption while maintaining the estimation accuracy.

Further, in the present embodiment, the power supply device 100 includes the battery state estimation device 1 described above, and a battery module having ten or more secondary batteries 2 whose battery states are estimated by the battery state estimation device 1. 10 and. Since the power supply device 100 has a large number of secondary batteries 2, by estimating the battery state by the battery state estimating device 1, while maintaining the estimation accuracy, the amount of calculation is greatly reduced, and the power consumption is greatly reduced. can be reduced.

As described above, according to the present embodiment, it is possible to provide the battery state estimation device 1 capable of estimating the battery state of the battery module 10 having a large number of secondary batteries 2 with low power consumption and high accuracy.

(Embodiment 6)
In the battery state estimation device 1 of Embodiment 6, instead of the target number setting unit 62 of Embodiment 5 shown in FIG. A section 510 is provided. Other components are the same as in the fifth embodiment, and the same reference numerals as in the fifth embodiment are used in this embodiment, and the description thereof is omitted.

The arithmetic expression storage unit 510 shown in FIG. 14 has the same configuration as in the case of the third embodiment. Calculation formula setting unit 620 shown in FIG. 14 sets a calculation formula for estimating the battery state based on the comparison result of SOC difference comparison unit 561 . The arithmetic expression is extracted from the arithmetic expression storage unit 510 by the arithmetic expression setting unit 620 . For example, when the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference is smaller than the SOC difference threshold value, the arithmetic expression setting unit 620 extracts an arithmetic expression with a light arithmetic load from the arithmetic expression storage unit 510, Set as an arithmetic expression for estimating the battery state. When the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference is not smaller than the SOC difference threshold value, the arithmetic expression setting unit 620 extracts an arithmetic expression with a not small arithmetic load from the arithmetic expression storage unit 510, Set as an arithmetic expression for estimating the battery state.

Next, the mode of use of the battery state estimation device 1 of this embodiment will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 15, steps S51 to S53 are the same as in the fifth embodiment shown in FIG. Then, in step S53, when the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference is smaller than the SOC difference threshold, the process proceeds to Yes in step S53, and in step S64, the arithmetic expression setting unit 620 , an arithmetic expression with a small arithmetic load is extracted from the arithmetic expression storage unit 510 and set as an arithmetic expression for estimating the battery state.

On the other hand, in step S53 shown in FIG. 15, if the comparison result of the SOC difference comparison unit 561 indicates that the SOC difference is not smaller than the SOC difference threshold, the process proceeds to No in step S53, and in step S65, calculation Expression setting unit 620 extracts the arithmetic expression in the initial state from arithmetic expression storage unit 510 and sets it as an arithmetic expression for estimating the battery state. Note that the computational expression in the initial state has a relatively large computational load.

Then, after steps S64 and S65 shown in FIG. 15, in step S66, the battery state estimation unit 64 estimates the battery states of all the secondary batteries 2 based on the set arithmetic expression, and performs this control. finish.

The effects of the battery state estimation device 1 of this embodiment will be described in detail below.
In the battery state estimating device 1 of the present embodiment, an arithmetic expression for estimating the battery state of a plurality of secondary batteries 2 is calculated based on the SOC difference as a specific value obtained from the secondary batteries 2 with a low calculation load. It is configured so that it can be changed to an arithmetic expression. As a result, it is possible to control to reduce the power consumed for the calculation while maintaining the calculation accuracy, and to suppress the heat generation.

In addition, in the present embodiment, when the SOC difference of the secondary battery 2 as a specific value is smaller than the SOC difference threshold, the battery state is estimated using an arithmetic expression with a small arithmetic load. As a result, when the SOC difference is small, there is little change in the battery state. Therefore, when the SOC difference is small, an arithmetic expression with a small computational load is used, thereby suppressing deterioration in estimation accuracy and maintaining the estimation accuracy. Power consumption can be reduced, and heat generation can be suppressed.

Also in the present embodiment, as in the fifth embodiment, the SOC difference threshold storage unit 550 in which a plurality of SOC difference threshold values are stored in advance is provided. An SOC difference threshold value is extracted from the SOC difference threshold storage unit 550 based on the temperature of the secondary battery 2, and the extracted SOC difference threshold value and the SOC difference calculated by the SOC difference calculation unit 560 are compared. As a result, the SOC difference threshold for comparison with the SOC difference in the plurality of secondary batteries 2 takes into consideration the SOC and temperature of the secondary batteries 2, so the SOC difference threshold corresponding to the variation in the battery state is extracted. can do. As a result, when the variation in the battery state of the secondary battery 2 is small, the battery state estimation target can be reduced, and while maintaining the estimation accuracy, the amount of calculation can be reduced to reduce power consumption, and heat generation can be achieved. can be suppressed.

(Embodiment 7)
In the battery state estimation device 1 of the seventh embodiment, instead of the SOC difference storage unit 541, the SOC difference threshold storage unit 550, the SOC difference calculation unit 560, and the SOC difference comparison unit 561 in the fifth embodiment shown in FIG. 2, includes an SOC-OCV curve storage unit 700, a slope storage unit 741, a slope threshold storage unit 750, a slope extraction unit 760, and a slope comparison unit 761. FIG. Further, a temperature acquisition unit 30 is provided. Other components are the same as in the fifth embodiment, and the same reference numerals as in the fifth embodiment are used in this embodiment, and the description thereof is omitted.

The SOC-OCV curve storage unit 700 shown in FIG. 16 preliminarily stores an SOC-OCV curve indicating the correspondence relationship between the SOC of the secondary battery 2 and the OCV, which is the open-circuit voltage. For example, the SOC-OCV curve shown in FIG. 17 is stored in the SOC-OCV curve storage unit 700. FIG. The SOC-OCV curve stored in the SOC-OCV curve storage unit 700 can be appropriately selected according to the type and configuration of the secondary battery 2 to be used.

The slope extraction unit 760 shown in FIG. 16 extracts the slope of the SOC-OCV curve from the SOC-OCV curve stored in the SOC-OCV curve storage unit 700 based on the SOC acquired by the SOC acquisition unit 530 as the specific value. do. The slope of the SOC-OCV curve refers to the slope of the tangent to the SOC-OCV curve at the SOC at the time of state estimation. Note that when the battery module 10 has a plurality of cell blocks each composed of a plurality of secondary batteries 2, the SOC of the cell block stored in the SOC storage unit 540 is used as the SOC of the plurality of secondary batteries 2, SOC- From the SOC-OCV curve stored in the OCV curve storage unit 700, the slope of the SOC-OCV curve can be extracted. The extracted tilt is stored in the tilt storage unit 741 .

The tilt comparison unit 761 shown in FIG. 16 extracts the tilt stored in the tilt storage unit 741 and the tilt threshold stored in the tilt threshold storage unit 750, and compares the two. Extraction of the slope threshold in the slope threshold storage unit 750 can be performed based on the temperature of the secondary battery 2 acquired by the temperature acquisition unit 30 . In the present embodiment, for example, when the slope threshold storage unit 750 stores slope threshold values as a map based on temperature as shown in FIG. A predetermined slope threshold can be extracted from the temperature of .

Then, the slope comparison unit 761 compares the extracted slope threshold with the slope stored in the slope storage unit 741 . In this embodiment, the slope comparison unit 761 compares the slope stored in the slope storage unit 741 with the slope threshold, and indicates the magnitude relationship between the slope and the slope threshold as a comparison result.

The target number setting unit 62 shown in FIG. 16 sets the target number, which is the number of secondary batteries 2 estimated by the battery state estimation unit 64 , based on the comparison result of the temperature difference comparison unit 61 . In this embodiment, when the comparison result of the slope comparison unit 761 indicates that the slope is smaller than the slope threshold value, the number-of-targets setting unit 62 reduces the number of targets. On the other hand, when the comparison result of the slope comparison unit 761 indicates that the slope is not smaller than the slope threshold value, the target number setting unit 62 does not reduce the target number and maintains the current target number.

Then, as in the case of the first embodiment, the target determination unit 63 determines the secondary batteries 2 to be estimated based on the number of targets set by the target number setting unit 62 . After that, the battery state estimating unit 64 estimates the battery state of the secondary battery 2 to be the estimation target determined by the target determining unit 63, as in the first embodiment. The battery state estimated by the battery state estimation unit 64 is not particularly limited, and the input/output power, chargeable/dischargeable power amount, input/output resistance, etc. of the secondary battery 2 can be estimated.

Next, the mode of use of the battery state estimation device 1 of this embodiment will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 19, the SOC of the secondary battery 2 is acquired by the SOC acquisition unit 530 in step S51, as in the case of the fifth embodiment. Then, the acquired SOC is stored in the SOC storage unit 540 . After that, in step S72, the slope extraction unit 760 extracts the slope of the SOC-OCV curve from the SOC stored in the SOC storage unit 540. FIG. Then, the extracted inclination is stored in the inclination storage unit 741 .

After that, as shown in FIG. 19, first, in step S73, the slope comparison unit 761 extracts the slope stored in the slope storage unit 740 and extracts the slope threshold value stored in the slope threshold storage unit 750. In this embodiment, the gradient threshold is extracted from the gradient threshold map shown in FIG. 18 based on the temperature of the secondary battery 2 extracted by the temperature acquisition unit 30 . Then, the tilt comparison unit 761 compares the extracted tilt and the tilt threshold value, and indicates the magnitude relationship between the tilt and the tilt threshold value as a comparison result.

Then, in step S73 shown in FIG. 19, if the comparison result of the slope comparison unit 761 indicates that the slope is smaller than the slope threshold value, the process proceeds to step S73 Yes, and in step S54, the target number setting unit 62 reduces the number of targets. On the other hand, if the comparison result of the slope comparison unit 761 in step S53 indicates that the slope is not smaller than the slope threshold value, the process proceeds to No in step S73, and in step S55, the number-of-targets setting unit 62 sets the number of targets. The number of targets is used as the initial value without reduction.

Then, after step S54 or step S55 shown in FIG. 19, in step S56, the target determination unit 63 determines the secondary battery 2 to be an estimation target. In the present embodiment, the target determining unit 63 selects the secondary battery 2 with a small slope as the estimation target after step S54. On the other hand, after execution of step S55, all secondary batteries 2 are subject to estimation. After that, in step S57, the battery state estimating unit 64 estimates the battery state of the secondary battery 2 set as the estimation target by the target determining unit 63, and this control ends.

Next, the effects of the battery state estimation device 1 of this embodiment will be described in detail.
According to the battery state estimating device 1, the battery state of a plurality of secondary batteries 2 is estimated based on the slope of the SOC-OCV curve extracted from the SOC, which is the specific value obtained from the secondary battery 2. is configured to be changeable. As a result, it is possible to control to reduce the power consumed for the calculation while maintaining the calculation accuracy, and to suppress the heat generation.

Further, in the present embodiment, the number-of-targets setting unit 62 decreases the number of targets when the comparison result of the slope comparing unit 761 indicates that the slope extracted by the slope extracting unit 760 is smaller than the slope threshold. In a plurality of secondary batteries 2, when the slope of the SOC-OCV curve is small, that is, when the amount of change in OCV with respect to SOC is small, variations in the battery state of the secondary batteries 2 are reduced. Therefore, as described above, in the battery module 10 including a plurality of secondary batteries 2, when the slope of the SOC-OCV curve of the secondary batteries 2 is small, the estimation accuracy is maintained by reducing the battery state estimation targets. , the amount of calculation can be reduced, the power consumption can be reduced, and heat generation can be suppressed.

Further, in this embodiment, a temperature acquisition unit 30 that acquires the temperature of the secondary battery 2 and a slope threshold storage unit 750 that stores a plurality of slope threshold values in advance are provided. extracts a slope threshold from the slope threshold storage unit 750 based on the acquired temperature, and compares the extracted slope threshold with the slope extracted by the slope extraction unit 760 . As a result, the slope threshold for comparison with the slopes of the SOC-OCV curves of the plurality of secondary batteries 2 takes into consideration the temperature of the secondary batteries 2, so the slope threshold corresponding to the variation in the battery state is extracted. can do. As a result, when the variation in the battery state of the secondary battery 2 is small, the battery state estimation target can be reduced, and while maintaining the estimation accuracy, the amount of calculation can be reduced to reduce power consumption, and heat generation can be achieved. can be suppressed.

(Embodiment 8)
The battery state estimation device 1 of the eighth embodiment includes an arithmetic expression setting unit 620 as shown in FIG. 20 in place of the target number setting unit 62 of the seventh embodiment shown in FIG. A section 510 is provided. Other components are the same as in the case of the fifth embodiment, and the same reference numerals as in the case of the seventh embodiment are used in the present embodiment, and the description thereof is omitted.

The arithmetic expression storage unit 510 has the same configuration as in the case of the third embodiment. The arithmetic expression setting unit 620 sets an arithmetic expression for estimating the battery state based on the comparison result of the slope comparison unit 761 . The arithmetic expression is extracted from the arithmetic expression storage unit 510 by the arithmetic expression setting unit 620 . For example, when the comparison result of the slope comparison unit 761 indicates that the slope is larger than the slope threshold value, the calculation formula setting unit 620 extracts a calculation formula with a small calculation load from the calculation formula storage unit 510, and determines the battery state. Set as an arithmetic expression for estimation. When the comparison result of the slope comparison unit 761 indicates that the slope is not larger than the slope threshold value, the calculation formula setting unit 620 extracts a calculation formula with a considerable calculation load from the calculation formula storage unit 510, and determines the battery state. Set as an arithmetic expression for estimation.

Next, the mode of use of the battery state estimation device 1 of this embodiment will be described with reference to the flowchart shown in FIG. First, as shown in FIG. 21, steps S51, S72, and S73 are the same as in the seventh embodiment shown in FIG. Then, in step S73, if the comparison result of the slope comparison unit 761 indicates that the slope is smaller than the slope threshold value, the process proceeds to Yes in step S73. An arithmetic expression with a low arithmetic load is extracted from the storage unit 510 and set as an arithmetic expression for estimating the battery state.

On the other hand, in step S73 shown in FIG. 21, if the comparison result of the slope comparison unit 761 indicates that the slope is not smaller than the slope threshold value, the process proceeds to No in step S73. 620 extracts the arithmetic expression in the initial state from the arithmetic expression storage unit 510 and sets it as the arithmetic expression for estimating the battery state. Note that the computational expression in the initial state has a relatively large computational load.

Then, after steps S64 and S65 shown in FIG. 21, in step S66, the battery state estimation unit 64 estimates the battery states of all the secondary batteries 2 based on the set arithmetic expression, and performs this control. finish.

The effects of the battery state estimation device of this embodiment will be described in detail below.
The battery state estimating device 1 of the present embodiment estimates the battery state of a plurality of secondary batteries 2 based on the slope of the SOC-OCV curve extracted from the SOC, which is the specific value obtained from the secondary battery 2. is configured to be able to change the computational expression for the calculation to a computational expression with less computational load. As a result, control can be performed so as to reduce the power consumed for calculation while maintaining the calculation accuracy, and heat generation can be suppressed.

Further, in this embodiment, when the comparison result of the slope comparison unit 761 indicates that the slope extracted by the slope extraction unit 760 is smaller than the slope threshold value, the calculation formula setting unit 620 selects the calculation formula with a small calculation load. set. In a plurality of secondary batteries 2, when the slope of the SOC-OCV curve is small, that is, when the amount of change in OCV with respect to SOC is small, variations in the battery state of the secondary batteries 2 are reduced. Therefore, as described above, in the battery module 10 including a plurality of secondary batteries 2, when the slope of the SOC-OCV curve of the secondary batteries 2 is small, the calculation formula with a small calculation load is set to maintain the estimation accuracy. In addition, the amount of calculation can be reduced, the power consumption can be reduced, and heat generation can be suppressed.

Also, in this embodiment, as in the case of Embodiment 7, a temperature acquisition unit 30 for acquiring the temperature of the secondary battery 2 and a slope threshold storage unit 750 in which a plurality of slope thresholds are stored in advance are provided. The slope comparison unit 761 extracts a slope threshold from the slope threshold storage unit 750 based on the temperature acquired by the temperature acquisition unit 30 and compares the extracted slope threshold with the slope extracted by the slope extraction unit 760 . As a result, the slope threshold for comparison with the slopes of the SOC-OCV curves of the plurality of secondary batteries 2 takes into consideration the temperature of the secondary batteries 2, so the slope threshold corresponding to the variation in the battery state is extracted. can do. As a result, it is possible to set an arithmetic expression with a small arithmetic load when the battery state of the secondary battery 2 has little variation, and it is possible to reduce the amount of arithmetic and power consumption while maintaining the estimation accuracy. , heat generation can be suppressed.

The present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the scope of the invention. For example, by combining the temperature difference in Embodiment 1 and the temperature in Embodiment 3 as specific values, the estimation accuracy can be maintained by reducing the estimation target of the battery state and by changing the calculation formula to one with less calculation load. Also, the power consumption may be suppressed by reducing the amount of calculation.

Further, by combining the temperature difference in the first embodiment and the SOC in the sixth embodiment as the specific value, the estimation accuracy is maintained by reducing the estimation target of the battery state and changing the computational expression to one with less computational load. Also, the power consumption may be suppressed by reducing the amount of calculation.

Further, in Embodiments 5 and 6, the configuration of the change determination section 67 that determines whether or not to change the number of targets based on the comparison result of the voltage difference comparison section 66 in Embodiment 2 may be applied. Further, in the seventh and eighth embodiments, the configuration of the change determination unit 67 that determines whether or not to change the setting of the arithmetic expression based on the comparison result of the voltage difference comparison unit 66 in the fourth embodiment may be applied.

1 battery state estimation device 2 secondary battery 10 battery module 30 temperature acquisition unit 31 voltage value acquisition unit 50 temperature difference threshold storage unit 51 voltage difference threshold storage unit 530 SOC acquisition unit 561 SOC difference comparison unit 61 temperature difference comparison unit 610 temperature comparison Part 62 Target number setting part 620 Operational formula setting part 63 Target determination part 64 Battery state estimation part 700 SOC-OCV curve storage part

Claims (14)

A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries whose battery state is to be estimated, can be changed ,
If it is determined that the variation in the battery state of the plurality of secondary batteries is small based on the specific value, the number of targets is reduced, and the variation in the battery state of the plurality of secondary batteries is not small. A battery state estimating device that maintains the number of targets if determined . 2. The battery state estimation device according to claim 1, wherein said specific value is calculated based on the temperature of said secondary battery. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries whose battery state is to be estimated, can be changed ,
The specific value is calculated based on the temperature of the secondary battery ,
a temperature acquisition unit (30) for acquiring temperatures of at least two secondary batteries;
a temperature difference calculation unit (60) for calculating a temperature difference between at least two temperatures obtained by the temperature obtaining unit as the specific value;
a temperature difference comparison unit (61) for comparing the temperature difference calculated by the temperature difference calculation unit with a preset temperature difference threshold;
a target number setting unit (62) for setting the target number based on the comparison result of the temperature difference comparison unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery corresponding to the number of targets set by the target number setting unit;
has
The target number setting unit reduces the number of targets when the comparison result of the temperature difference comparison unit indicates that the temperature difference calculated by the temperature difference calculation unit is smaller than the temperature difference threshold. . A temperature difference threshold storage unit (50) in which a plurality of temperature difference threshold values are stored in advance,
The temperature difference comparison unit extracts the temperature difference threshold from the temperature difference threshold storage unit based on one of the at least two temperatures acquired by the temperature acquisition unit, and extracts the temperature difference threshold and the temperature. comparing with the temperature difference calculated by the difference calculation unit;
The battery state estimating device according to claim 3 . a voltage value acquisition unit (31) for acquiring terminal voltages of the plurality of secondary batteries;
a voltage difference calculation unit (65) for calculating the difference from the plurality of voltage values acquired by the voltage value acquisition unit;
a voltage difference comparison unit (66) that compares the voltage difference calculated by the voltage difference calculation unit with a preset voltage difference threshold;
a change determination unit (67) that determines whether or not to change the number of targets based on the comparison result of the voltage difference comparison unit;
with
The battery state estimation device according to claim 3 or 4 , wherein the target number setting unit changes the target number based on a determination result of the change determination unit. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the arithmetic expression for estimating the battery state of the secondary battery can be changed to an arithmetic expression with a small calculation load,
The specific value is calculated based on the temperature of the secondary battery,
a temperature acquisition unit (30) for acquiring the temperature of the secondary battery as the specific value;
a temperature comparison unit (610) that compares the temperature acquired by the temperature acquisition unit with a preset temperature threshold;
an arithmetic expression setting unit (620) for setting an arithmetic expression for estimating the battery state based on the comparison result of the temperature comparison unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery based on the arithmetic expression set by the arithmetic expression setting unit;
has
When the comparison result of the temperature comparing unit indicates that the temperature acquired by the temperature acquiring unit is higher than the temperature threshold, the computing equation setting unit sets a computing equation with a small computational load as the computing equation . The battery state estimating device described. a voltage value acquisition unit (31) for acquiring terminal voltages of the plurality of secondary batteries;
a voltage difference calculation unit (65) for calculating the difference from the plurality of voltage values acquired by the voltage value acquisition unit;
a voltage difference comparison unit (66) that compares the voltage difference calculated by the voltage difference calculation unit with a preset voltage difference threshold;
a change determination unit (67) that determines whether or not to change the setting of the arithmetic expression based on the comparison result of the voltage difference comparison unit;
with
The battery state estimation device according to claim 6 , wherein the arithmetic expression setting unit changes the setting of the arithmetic expression based on the determination result of the change determination unit. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries whose battery state is to be estimated, can be changed,
The specific value is calculated based on the SOC, which is the state of charge of the secondary battery,
an SOC acquisition unit (530) that acquires the SOC of at least two of the secondary batteries;
an SOC difference calculator (560) that calculates the difference between at least two SOCs obtained by the SOC obtaining unit as the specific value;
an SOC difference comparison unit (561) that compares the SOC difference calculated by the SOC difference calculation unit with a preset SOC difference threshold;
a target number setting unit (62) for setting the number of targets based on the comparison result of the SOC difference comparison unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery corresponding to the number of targets set by the target number setting unit;
has
The target number setting unit reduces the target number when the comparison result of the SOC difference comparison unit indicates that the SOC difference calculated by the SOC difference calculation unit is smaller than the SOC difference threshold. Device. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the arithmetic expression for estimating the battery state of the secondary battery can be changed to an arithmetic expression with a small calculation load,
The specific value is calculated based on the SOC, which is the state of charge of the secondary battery,
an SOC acquisition unit (530) that acquires the SOC of at least two of the secondary batteries;
an SOC difference calculator (560) that calculates the difference between at least two SOCs obtained by the SOC obtaining unit as the specific value;
an SOC difference comparison unit (561) that compares the SOC difference calculated by the SOC difference calculation unit with a preset SOC difference threshold;
an arithmetic expression setting unit (620) for setting an arithmetic expression for estimating the battery state based on the comparison result of the SOC difference comparing unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery based on the arithmetic expression set by the arithmetic expression setting unit;
has
When the comparison result of the SOC difference comparing unit indicates that the SOC difference calculated by the SOC difference calculating unit is smaller than the SOC difference threshold value, the arithmetic expression setting unit sets , the battery state estimation device. An SOC difference threshold storage unit (550) in which a plurality of the SOC difference thresholds are stored in advance,
The SOC difference comparison unit extracts the SOC difference threshold from the SOC difference threshold storage unit based on the SOC acquired by the SOC acquisition unit or the temperature of the secondary battery, and extracts the SOC difference threshold and the SOC difference. The battery state estimating device according to claim 8 or 9 , which is compared with the SOC difference calculated by the calculator. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the number of targets, which is the number of the secondary batteries whose battery state is to be estimated, can be changed,
The specific value is calculated based on the SOC, which is the state of charge of the secondary battery,
an SOC acquisition unit (530) that acquires the SOC of the secondary battery;
an SOC-OCV curve storage unit (700) storing in advance an SOC-OCV curve indicating the correspondence relationship between the SOC and the OCV, which is the open-circuit voltage, of the secondary battery;
A slope extraction unit (760) for extracting the slope of the SOC-OCV curve from the SOC-OCV curve stored in the SOC-OCV curve storage unit based on the SOC acquired by the SOC acquisition unit as the specific value. When,
a slope comparison unit (761) that compares the slope extracted by the slope extraction unit with a preset slope threshold;
a number-of-objects setting unit (62) for setting the number of objects based on the comparison result of the slope comparison unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery corresponding to the number of targets set by the target number setting unit;
has
The battery state estimation device, wherein the target number setting unit reduces the number of targets when the comparison result of the slope comparison unit indicates that the slope extracted by the slope extraction unit is smaller than the slope threshold value. A battery state estimation device (1) for estimating a battery state in a battery module (10) having a plurality of secondary batteries (2),
Based on the specific values obtained from the plurality of secondary batteries, the arithmetic expression for estimating the battery state of the secondary battery can be changed to an arithmetic expression with a small calculation load,
The specific value is calculated based on the SOC, which is the state of charge of the secondary battery,
an SOC acquisition unit (530) that acquires the SOC of the secondary battery;
an SOC-OCV curve storage unit (700) storing in advance an SOC-OCV curve indicating the correspondence relationship between the SOC and the OCV, which is the open-circuit voltage, of the secondary battery;
A slope extraction unit (760) for extracting the slope of the SOC-OCV curve from the SOC-OCV curve stored in the SOC-OCV curve storage unit based on the SOC acquired by the SOC acquisition unit as the specific value. When,
a slope comparison unit (761) that compares the slope extracted by the slope extraction unit with a preset slope threshold;
an arithmetic expression setting unit (620) for setting an arithmetic expression for estimating the battery state based on the comparison result of the slope comparison unit;
a battery state estimating unit (64) for estimating the battery state of the secondary battery based on the arithmetic expression set by the arithmetic expression setting unit;
has
The arithmetic expression setting unit sets an arithmetic expression with a small arithmetic load as the arithmetic expression when the comparison result of the inclination comparison unit indicates that the inclination extracted by the inclination extraction unit is smaller than the inclination threshold. Battery state estimation device. a temperature acquisition unit (30) for acquiring the temperature of the secondary battery;
a tilt threshold storage unit (750) in which a plurality of tilt threshold values are stored in advance;
with
The slope comparison unit extracts the slope threshold from the slope threshold storage unit based on the temperature acquired by the temperature acquisition unit, and compares the extracted slope threshold with the slope extracted by the slope extraction unit. The battery state estimating device according to claim 11 or 12 . The battery state estimating device according to any one of claims 1 to 13, and the battery module having 10 or more secondary batteries configured so that the battery state is estimated by the battery state estimating device and a power supply.

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