JP4820329B2 - Storage amount calculation device and storage amount calculation method - Google Patents

Description

  The present embodiment relates to a technique for a storage amount calculation device and a storage amount calculation method.

As a method for calculating a state of charge (SOC) of a battery (power storage device) used as a secondary battery in a vehicle equipped with a motor for traveling, a ship, and the like, a current integration calculation method, an upper and lower limit voltage SOC are conventionally used. There are a calculation method, a DC-R (Direct Current-Resistance) calculation method (voltage method), and the like.
The current value integration calculation method integrates the value (battery current value) of the current discharged from or charged to the battery (battery current value), and divides the integrated battery current value by the battery capacity. This is a method of calculating the SOC.
The upper / lower limit SOC calculation method uses a battery capacity-terminal voltage characteristic map and a battery capacity-battery temperature characteristic map that are unique to each type of battery. This is a method of calculating the SOC near the upper limit (approximately 80% or more at full charge) or near the lower limit (approximately 20% or less at full charge) based on the battery terminal voltage value and the battery temperature.
The DC-R calculation method is a method of detecting the OCV (Open Circuit Voltage) of the battery and calculating the SOC using a preset SOC-OCV characteristic. Here, the OCV is calculated by adding a value obtained by multiplying each single cell voltage by the battery current and the internal resistance of the battery to the single cell voltage. Here, a single cell voltage is the voltage for every single cell battery acquired from the voltage sensor provided for every single cell battery which comprises a battery.

Patent Document 1 discloses a battery charge amount detection device that calculates an SOC by a current value integration calculation method and corrects an estimated SOC value when the SOC reaches an IV determination region of 20% or less or 80% or more. It is disclosed.
JP-A-11-174134 (FIGS. 3 and 4)

The above-described current integration calculation method, upper / lower limit voltage SOC calculation method, and DC-R calculation method have advantages and disadvantages, respectively.
The current integration calculation method has an advantage that it can cope with a sudden change in the battery current value, but the error of the sensor that measures the current value is also integrated, so that the error increases with time.
The upper / lower limit SOC calculation method can calculate the SOC with high accuracy, but as described above, it can only determine the SOC near the upper limit or near the lower limit.
In the DC-R calculation method, a battery with a clear relationship between OCV and SOC, such as a Li (Lithium) -ion battery, can calculate the charged amount with higher accuracy than the current integration calculation method. However, it is necessary to calculate the internal resistance of the battery in calculating the OCV. Accordingly, if the calculation accuracy of the internal resistance is lowered due to a sudden change in the current value, it is difficult to calculate the SOC by the DC-R calculation method.

In the conventional calculation of the SOC, the current integration calculation method is mainly used, and the upper and lower limit SOC calculation methods are often used as correction means.
That is, a method is used in which the error accumulated in the current integration calculation method as described above is corrected using the upper and lower limit SOC calculation methods. However, as described above, the upper / lower limit SOC calculation method can only obtain the SOC in the vicinity of the upper / lower limit, and therefore, the current integration calculation method can only be used in other portions.
In addition, when there is a difference between the SOCs calculated by the two, a phenomenon occurs in which the SOC rapidly changes when switching from the current integration calculation method to the upper / lower limit SOC calculation method. Due to such a phenomenon, for example, in a system in which a high-voltage battery and a fuel cell are used in combination to drive a traveling motor, the power distribution between the battery and the fuel cell also changes abruptly. If the power distribution changes abruptly, efficient driving cannot be performed, which may lead to deterioration in fuel consumption. Furthermore, sudden output limitation of the fuel cell may occur, and drivability may be impaired. The same applies to electric vehicles and HEVs, which are controlled using SOC as an index.

  Therefore, an object of the present invention is to provide a storage amount calculation device and a storage amount calculation method capable of selecting an appropriate storage amount calculation method for the state of a measured value from a battery.

The invention according to claim 1 of the present invention that solves the above-mentioned problem is a storage amount calculation device that calculates a storage amount of a storage device that supplies power to a load, and that the storage unit detects by the voltage value detection unit A voltage value in the device, a measurement value acquisition unit that acquires a current value in the power storage device detected by a current value detection unit, a storage unit that stores the acquired current value, and the acquired and stored current value, Using a current integration calculation method for calculating the storage amount by integrating with respect to time, a current integration calculation unit that calculates the storage amount, a voltage value acquired by the measurement value acquisition unit, and a correlation between the storage amount And a voltage method calculation unit for calculating the storage amount based on the voltage method for calculating the storage amount, and the acquired current value within a predetermined time range is a predetermined current value amplitude range. Within Whole time, and the obtained and determines the current stability judgment unit current value is stabilized, by the current regulation determination unit, when the current value is determined to be stable, the current integration calculation method of the power storage amount After the calculation method is switched to the voltage method, and the current stability determination unit determines that the current value is stable, the determination unit determines whether the current value is stable. A storage amount calculation method switching unit that switches from the calculation of the storage amount by the voltage method to the calculation of the storage amount by the current integration calculation method when it is determined that the measurement value is not stable; The unit further has a function of detecting the temperature of the power storage device from a temperature detection unit, the current value amplitude range decreases as the temperature of the power storage device decreases, and the time range includes the power storage device Characterized in that it is set to be longer as the temperature decreases.

According to the first aspect of the present invention, it is possible to specify a region where the calculation accuracy of the internal resistance of the power storage device is high by measuring the stability of the current value in the power storage device. This makes it easy to switch the method for calculating the amount of electricity stored according to the stability of the current value, and the current value stability can be measured in consideration of the temperature of the power storage device. The calculation method can be switched.

The invention according to claim 2 is the storage amount calculation device according to claim 1, wherein the determination unit switches the calculation method of the storage amount to the voltage method, and then uses the current value detection unit. The difference between the detected first current value and the second current value detected before the first current value and stored in the storage unit is determined from the time of detection of the second current value. The slope of the current value change is calculated by dividing by the time until the detection of the first current value, and the current value is stable when the calculated slope of the current value change is greater than a predetermined value. It is characterized by not determining.

According to the second aspect of the invention, it is possible to accurately calculate the amount of electricity stored by switching to an appropriate method for calculating the amount of electricity stored according to the state of change in the current value, which is one of the measured values in the electricity storage device. It becomes.

The invention according to claim 3 is the electricity storage amount calculation device according to claim 1 or claim 2 , wherein the electricity storage amount calculation device includes an upper limit electricity storage amount of the electricity storage device and the voltage value. When the relationship and the relationship between the lower limit storage amount and the voltage value are input in advance, and the voltage value is equal to the voltage value indicating the upper limit storage amount, the upper limit storage amount is set as the storage amount of the storage device. and then, the voltage value is equal to the voltage value indicating the lower limit accumulation amount, and further comprising a lower limit accumulation amount calculating section on the lower limit storage amount and storage amount of the power storage device.

According to the invention of claim 3 , when the voltage value indicates a voltage value corresponding to the upper limit storage amount or a voltage value corresponding to the lower limit storage amount, the storage amount is set to the upper limit storage amount or the lower limit storage amount. Thus, overcharge and overdischarge of the power storage device can be prevented.

The invention according to claim 4 is the storage amount calculation device according to any one of claims 1 to 3 , wherein the calculation is performed when the method for calculating the storage amount of the storage device is switched. The first power storage amount is compared with the second power storage amount calculated before the calculation of the first power storage amount, and a difference between the first power storage amount and the second power storage amount is set in advance. If the power storage amount is larger than a predetermined value, a change process for gradually changing the storage amount from the second storage amount to the first storage amount is performed, and the current is obtained from the voltage method during the replacement process. When switching to the integration calculation method occurs, the system further includes a change processing unit that integrates the current value from the amount of electricity stored at the switching time.

According to the invention of claim 4 , when the method for calculating the storage amount is switched, if the difference between the storage amount calculated before switching and the storage amount calculated after switching is large, the calculated storage amount is By performing the change-over process that gradually changes, it is possible to continuously change the power storage amount calculated before switching and the power storage amount calculated after switching.
Furthermore, during the change-over process, even if switching from the calculation of the storage amount by the voltage method to the calculation of the storage amount by the current integration calculation method occurs, the integration of the current starts from the storage amount calculated at that time, It is possible to continuously change the storage amount calculated before switching and the storage amount calculated after switching.
As described above, by continuously changing the storage amount calculated before the switching and the storage amount calculated after the switching, it is possible to suppress the steep operation of the vehicle due to the change in the storage amount when the vehicle is switched. , Drivability is improved.

The invention according to claim 5 is a storage amount calculation method in a storage amount calculation device that calculates a storage amount of a storage device that supplies power to a load, wherein the storage amount calculation device is detected by a voltage value detection unit. voltage value at the energy storage device, and obtains the current value in the power storage device current value detection unit detects, by detecting a temperature of the power storage device from the temperature detection unit, and stores the obtained current value, the A current value amplitude range in which the acquired current value is set to decrease with a temperature decrease of the power storage device within a time range set to increase with a temperature decrease of the power storage device. when fit within, and determines that the obtained current value is stabilized, when the current value is determined to be stable, the pre-Symbol acquisition and the stored current value, depending on by integrating with respect to time From current integration calculation method for calculating the charged amount, and the voltage value the acquired, based on the correlation between the charged amount, the voltage method of calculating the power storage amount, switches the method for calculating the charged amount, the current after the value is determined to have stabilized, when the current value is determined not to be stable, the storage amount from the amount of charge calculated by the voltage method, to the storage amount of calculation by the current integration calculation method The calculation method is switched.
The invention according to claim 6 is the storage amount calculation method according to claim 5, wherein the storage amount calculation device switches the calculation method of the storage amount to the voltage method, and then detects the current value. The difference between the first current value detected by the unit and the second current value detected before the first current value and stored in the storage unit is detected as the second current value. The slope of the current value change is calculated by dividing by the time from when the first current value is detected, and the current value is stable when the calculated slope of the current value change is greater than a predetermined value. It is characterized by determining that it is not.

According to the invention which concerns on Claim 5 , there can exist an effect similar to invention of Claim 1.
Moreover, according to the invention which concerns on Claim 6, there can exist an effect similar to the invention of Claim 2.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage amount calculation apparatus which can select the calculation method of an appropriate electrical storage amount with respect to the state of the measured value from a battery can be provided.

Next, the best mode for carrying out the present invention (referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate.
In addition, although the battery in this embodiment assumes the Li-ion battery, you may apply to another battery.

FIG. 1 is a diagram illustrating a configuration example of the SOC calculation system in the present embodiment.
The SOC calculation system 10 is connected to the battery 2 via a contactor 4 and a battery 2 used as a secondary battery. The load 3 that consumes power supplied from the battery 2, the battery 2, and the contactor 4 and an SOC calculation device 1 (power storage amount calculation device) that calculates the SOC based on the information acquired from the battery 2 and the contactor 4. The load 3 may be a travel motor, for example.

  The battery 2 includes a current sensor 6 that measures a current value (battery current value) between terminals of the battery 2, a voltage sensor 5 that measures a voltage value (battery voltage value) between battery terminals, and the temperature of the battery 2 (battery). A temperature sensor 7 for measuring (temperature) is provided.

The SOC calculation device 1 includes a processing unit 11 that performs various types of processing, a storage unit 12 that stores various types of information, a measurement value acquisition unit 13, and a contactor connection monitoring unit 14.
The measurement value acquisition unit 13 acquires a battery current value from the current sensor 6 provided in the battery 2, acquires a battery voltage value from the voltage sensor 5, and acquires a battery temperature from the temperature sensor 7. And has a function of sending the acquired various measurement values to the processing unit 11.
The contactor connection monitoring unit 14 has a function of acquiring information such as whether or not the contactor 4 is connected and sending the acquired information to the processing unit 11.

The storage unit 12 is connected to the processing unit 11 and has a function of storing information such as a battery temperature-replacement determination time map 121 and a battery temperature-replacement current range map. Moreover, it has the function to store the measurement value which the measurement value acquisition part 13 acquired, the value which the process part 11 calculated, information required for calculation of various SOC, etc.
The battery temperature-replacement determination time map 121 and the battery temperature-replacement current range map 122 will be described later with reference to FIG.

The processing unit 11 includes a DC-R calculation unit 101 (voltage method calculation unit), a current integration calculation unit 102, an upper / lower limit SOC calculation unit 103 (upper / lower limit charged amount calculation unit), a change determination time setting unit 104, a change current. It has a range setting unit 105, a current stability determination unit 106, a transfer processing unit 107, an SOC selection unit 108, a calculation unit 109, and a determination unit 110.
The DC-R calculation unit 101 has a function of calculating the SOC by the DC-R calculation method based on the value acquired by the measurement value acquisition unit 13 and the like. The current integration calculation unit 102 has a function of calculating the SOC by the current integration calculation method based on the battery current value acquired by the measurement value acquisition unit 13 or the battery current value stored in the storage unit 12.

Based on the battery temperature acquired by the measurement value acquisition unit 13, the transfer determination time setting unit 104 sets the transfer determination time with reference to the battery temperature-transfer determination time map 121 stored in the storage unit 12. It has the function to do.
Based on the battery temperature acquired by the measurement value acquisition unit 13, the replacement current range setting unit 105 sets the replacement current range with reference to the battery temperature-replacement current range map 122 stored in the storage unit 12. It has the function to do.
The turnover determination time and the turnover current range will be described later with reference to FIGS. 3 and 4.

The current stability determination unit 106 has a function of determining a stable state of the battery current value.
The change processing unit 107 has a function of performing a change processing described later with reference to FIG.
The SOC selection unit 108 (power storage amount calculation method switching unit) selects an SOC suitable for the state of the battery 2 from among the SOCs calculated by various methods, so that the SOC suitable for the measurement value from the battery 2 is selected. It has a function to switch to a value.
The calculation unit 109 has a function of performing various calculations, and the determination unit 110 has a function of performing a determination other than the determination of the stable state of the battery current value.
In the processing unit 11 and each of the units 101 to 110, a program stored in a storage device such as a ROM (Read Only Memory) (not shown) is expanded in a RAM (Random Access memory) (not shown), and a CPU (Central Processing Unit) (not shown). It is embodied by being executed by.

FIG. 2 is a diagram illustrating an example of a battery temperature-replacement determination time map and a battery temperature-replacement current range map. FIG. 2A is a diagram illustrating an example of a battery temperature-replacement determination time map. (B) is a figure showing an example of a battery temperature-exchange current range map.
Note that the battery temperature-replacement determination time map 121 and the battery temperature-replacement current range map 122 are stored in the storage unit 12 in the form of a numerical table. Show.
In FIG. 2A, the horizontal axis is the battery temperature, and the vertical axis is the changeover determination time. In FIG. 2B, the horizontal axis is the battery temperature and the vertical axis is the replacement current range.
As shown in FIG. 2A, in the battery temperature-replacement determination time map 121, when the battery temperature rises, the internal resistance in the battery 2 decreases , so the relocation determination time decreases, and the battery temperature decreases. Then, since internal resistance increases , it is set so that the changeover determination time increases.
As shown in FIG. 2B, in the battery temperature-carrying current range map 122, when the battery temperature rises, the internal resistance decreases, so that the caging current range increases and the battery temperature falls. Since the internal resistance increases, the replacement current range is set to decrease. Although the graph of FIG. 2B is stepped, it is sufficient that the replacement current range increases as the battery temperature rises. For example, the graph may be linear or curved. Good.
Note that the change-over determination time is a time necessary for determining whether or not the battery current is stable. The exchange current range is a range of change in battery current for determining whether or not the battery current is stable. The relocation determination time and the relocation current range will be described later with reference to FIG.

Next, the SOC calculation method in the present embodiment will be described along FIGS. 3A and 3B with reference to FIGS. 1 and 2.
FIG. 3A and FIG. 3B are flowcharts showing a processing flow of the storage amount calculation method in the present embodiment. The processing shown in FIGS. 3A and 3B is started by turning on the ignition key of the vehicle, and is ended when the ignition key is turned off.
First, a description will be given from FIG. 3A.
First, the measurement value acquisition unit 13 acquires various measurement values such as a battery current value measured by the current sensor 6, a battery voltage value measured by the voltage sensor 5, and a battery temperature measured by the temperature sensor 7. The value is stored in the storage unit 12 (S101).
Then, the calculation unit 109 acquires the current battery current value and the past predetermined number of battery current values from the storage unit 12, calculates a moving average of the battery current values, and stores the calculated moving average value as the storage unit 12. (S102).
Next, the DC-R calculation unit 101 calculates SOC (DC-RSOC) by the DC-R calculation method using the acquired battery current value, battery voltage value, and the like (S103).
Then, the current integration calculation unit 102 calculates SOC (current integration SOC) by the current integration calculation method using the acquired battery current value (S104). In step S104, the SOC is calculated by integrating the current integration calculation unit 102 current with the SOC value finally selected in the previous process. That is, for example, if DC-RSOC is finally selected in the previous process, the current integrated SOC is calculated by adding the battery current value acquired in step S101 to the value of DC-RSOC.
Further, the upper / lower limit SOC calculation unit 103 calculates the SOC (upper / lower limit SOC) by the upper / lower limit SOC calculation method using the battery current value, the battery temperature acquired in step S101, or the like (S105). In step S105, if the battery current value and the battery voltage value are values that are not applicable to the upper / lower limit SOC calculation method, for example, an error is output. Whether the battery current value and the battery voltage value can be applied to the upper / lower limit SOC calculation method can be determined by using IV determination or the like.

Next, the contactor connection monitoring unit 14 determines whether or not the contactor 4 is connected (S106).
When it is determined in step S106 that the contactor 4 is not connected (S106 → No), the SOC selection unit 108 selects the DC-RSOC calculated in step S103 as the SOC (S107). And the process part 11 advances a process to step S119.
If it is determined in step S106 that the contactor 4 is connected (S106 → Yes), the transfer determination time setting unit 104 is stored in advance in the storage unit 12 based on the battery temperature acquired in step S101. With reference to the battery temperature-transfer determination time map 121 (see FIG. 2A), the transfer determination time is set (S108).
Next, the replacement current range setting unit 105 refers to a preset battery temperature-replacement current range map 122 (see FIG. 2B) based on the battery temperature acquired in step S101. A carrying current range is set (S109).

Next, the current stability determination unit 106 determines whether or not the battery current value acquired in step S101 is a value within the replacement current range set in step S109 (S110).
In step S110, if the battery current value is within the replacement current range, the calculation unit 109 subtracts 1 from the timer value (S111), and the processing unit 11 proceeds to the processing of step S113.
In step S110, when the battery current value is not within the replacement current range, the calculation unit 109 resets the timer value to the replacement determination time value set in step S108 (S112).

Next, the current stability determination unit 106 determines whether or not the timer value is 0 (S113).
If it is determined in step S113 that the timer value is not 0 (S113 → No), that is, if the current time is within the turnover determination time, the SOC selection unit 108 calculates the current integrated SOC calculated in step S104. Select (S114). And the process part 11 advances a process to step S119.
In step S113, when it is determined that the timer value is 0 (S113 → Yes), that is, when the turnover determination time is ended, the calculation unit 109 reads the battery current value in the previous process from the storage unit 12 (previous time). Value), and the difference between the previous value and the battery current value in the current process (that is, the battery current value acquired in step S101: current value), the time when the previous value was acquired, and the current value The current change is calculated by dividing by the time between the acquired time. Then, the current stability determination unit 106 determines whether or not the current change is equal to or less than a predetermined value set in advance (S115). The current change in step S115 will be described later with reference to FIG.
If the calculated current change is not less than or equal to the predetermined value in step S115 (S115 → No), the current stability determination unit 106 determines that the battery current value is not yet stable, and proceeds to step S114.

In step S115, when the calculated current change is equal to or smaller than the predetermined value (S115 → Yes), the determination unit 110 determines the SOC value (previous SOC) finally selected from the storage unit 12 in the previous process, It is determined whether or not the difference from the DC-RSOC value (current SOC) calculated in step S103 is 0 (S116).
If the difference between the previous SOC and the current SOC is not 0 as a result of step S116 (S116 → No), the change processing unit 107 performs a change process (S117). Details of the carry-over process will be described later with reference to FIG.
As a result of Step S116, when the difference between the previous SOC and the current SOC is 0 (S116 → Yes), the SOC selection unit 108 selects the DC-RSOC calculated in Step S103 (S118).

  As described above, when the upper and lower limit SOCs are calculated, the upper and lower limit SOCs are set as the SOC, so that it is possible to calculate the SOC with high accuracy and to prevent the battery 2 from being overcharged or overdischarged. It becomes possible.

Next, the determination unit 110 determines whether or not an upper / lower limit SOC exists by determining whether or not an error is output in the process of step S105 (S119).
If it is determined in step S119 that the upper / lower limit SOC does not exist (S119 → No), the SOC selection unit 108 stores the SOC selected in step S107, step S114, or step S118 in the storage unit 12 (S120). The process part 11 returns to the process of step S101.
When it is determined in step S119 that the upper and lower limit SOCs are present (S119 → Yes), the current stability determination unit 106 determines the SOC value (previous SOC) finally selected from the storage unit 12 in the previous process, It is determined whether or not the difference from the upper / lower limit SOC value (current SOC) calculated in step S105 is 0 (S121).
If the difference between the previous SOC and the current SOC is not 0 as a result of step S121 (S121 → No), the change processing unit 107 performs a change process (S122). Details of the carry-over process will be described later with reference to FIG.
As a result of step S121, when the difference between the previous SOC and the current SOC is 0 (S121 → Yes), the SOC selection unit 108 selects the upper / lower limit SOC calculated in step S105 (S123), and stores it in the storage unit 12. The selected upper and lower limit SOC values are stored (S124). And the process part 11 returns to the process of step S101.

Next, with reference to FIG. 1 to FIG. 3B, the changing process will be described along FIG. 4.
4A and 4B are diagrams for explaining the change-over process, in which FIG. 4A is a diagram showing the behavior of the battery current value, and FIG. 4B is a diagram showing the behavior of the SOC.
In FIG. 4A, the horizontal axis is time, and the vertical axis is the battery current value.
A solid line 1001 indicates a battery current value. Here, the battery current value 1001 is a moving average value calculated by the calculation unit 109 in step S102. By using the moving average in this way, it is possible to cancel the noise on the battery current value 1001.
Time t0 indicates the time when the timer is reset in step S112A of FIG. 3, and time t1 indicates the time when the timer is determined to be 0 in step S113 of FIG. 3A.
The change determination time is between time t0 and time t1. The change determination time is set in step S108 of FIG. 3A according to the battery temperature-change determination time map 121 shown in FIG.
In addition, the range of the current value between the current value I1 and the current value I2 is a replacement current range. This exchange current range is also set in step S109 of FIG. 3A according to the battery temperature-exchange current range map 122 shown in FIG. For example, the current value I1 and the current value I2 are set around an average value of current values in the past.

As shown in FIG. 4A, when the battery current value 1001 continues to fall within the replacement current range during the replacement determination time, the current stability determination unit 106 determines that the battery current value is stable ( (Yes in step S113 in FIG. 3B).
Also, the current change in step S113 in FIG. 3A is the slope of the battery current value 1001 in FIG. 4A with respect to time. As shown in FIG. 4 (a), even when the battery current value 1001 continues to fall within the replacement current range during the replacement determination time, the current change, that is, the slope of the battery current value 1001 is not less than a predetermined value. If there is, the determination unit 110 determines that the battery current value is not stable (No in step S115 in FIG. 3A), and the SOC selection unit 108 selects the SOC based on the current integration calculation method (step S114 in FIG. 3A). ).
It should be noted that the “predetermined value” at this time is that the current integration calculation method can calculate the SOC more accurately than the DC-R calculation method at a steep slope greater than or equal to this value. A value is set so that the DC-R calculation method can calculate the SOC more accurately than the current integration calculation method.

  In addition, when the battery current value exceeds the replacement current range even though the replacement determination time has not ended, the processing unit 11 resets that time as the start time of the replacement determination time. (Step S112 in FIG. 3), during the changeover determination time, it is determined again whether or not the battery current value exceeds the replacement current range.

Next, an example of the transfer process will be described with reference to FIG.
Here, an example of processing for switching from SOC by the current integration calculation method to SOC by the DC-R calculation method will be described. Since time is the same as that in FIG. 4A, description thereof is omitted.
In FIG.4 (b), a horizontal axis shows time and a vertical axis | shaft shows SOC.
Reference numeral 2001 indicates SOC (current integrated SOC) based on the current integration calculation method, and reference numeral 2002 indicates SOC (DC-RSOC) based on the DC-R calculation method.
In step S115 in FIG. 3A, when the current change at time t1 is equal to or smaller than a predetermined value (arrow 2002 in FIG. 4A), the determination unit 110 determines the current value of DC-RSOC 2001 (current value: reference numeral 2003). ) And the value of the current integration SOC 2002 (previous value: symbol 2004) in the previous process is determined (step S121 in FIG. 3B). As shown in FIG. 4B, when there is a difference between the current value and the previous value, the value of the current integration SOC 2001 is changed to the value of DC-RSOC 2002 by a predetermined value until the value becomes the same as the value of DC-RSOC 2002. By moving closer (broken line 2005), the change process is performed.

  In this way, by performing the carry-over process, it is possible to prevent the SOC value from changing suddenly at the moment when the SOC calculation method is switched. Along with this, it is possible to prevent an abrupt change in the power distribution from the battery 2, to prevent a deterioration in fuel consumption, and to prevent a sudden output restriction, thereby improving drivability. Can do.

(Modification)
In the present embodiment, the battery current value is used for the determination in step S110 or step S115 of FIG. 3, but the present invention is not limited to this, and a battery voltage value may be used.

It is a figure which shows the structural example of the SOC calculation system in this embodiment. It is a figure which shows the example of a battery temperature-exchange determination time map and a battery temperature-exchange current range map, (a) is a figure which shows the example of a battery temperature-exchange determination time map, (b) It is a figure which shows the example of a battery temperature-carrying-out electric current range map. It is a flowchart which shows the flow of a process of the electrical storage amount calculation method in this embodiment (the 1). It is a flowchart which shows the flow of a process of the electrical storage amount calculation method in this embodiment (the 2). It is a figure for demonstrating a carrying-over process, (a) is a figure which shows the behavior of a battery electric current value, (b) is a figure which shows the behavior of SOC.

Explanation of symbols

1 SOC calculation device (power storage amount calculation device)
DESCRIPTION OF SYMBOLS 3 Load 4 Contactor 5 Voltage sensor 6 Current sensor 7 Temperature sensor 10 SOC calculation system 11 Processing part 12 Memory | storage part 13 Measurement value acquisition part 14 Contactor connection monitoring part 101 DC-R calculation part (voltage method calculation part)
102 current integration calculation unit 103 upper / lower limit SOC calculation unit (upper / lower limit storage amount calculation unit)
104 change determination time setting unit 105 change current range setting unit 106 current stability determination unit 108 SOC selection unit (power storage amount calculation method switching unit)
109 Calculation Unit 110 Determination Unit 121 Battery Temperature-Replacement Determination Time Map 122 Battery Temperature-Replacement Current Range Map

Claims (6)

A power storage amount calculation device that calculates a power storage amount of a power storage device that supplies power to a load,
A measurement value acquisition unit that acquires a voltage value in the power storage device detected by the voltage value detection unit and a current value in the power storage device detected by the current value detection unit;
A storage unit for storing the acquired current value;
A current integration calculation unit that calculates the amount of stored electricity using a current integration calculation method that calculates the amount of stored electricity by integrating the acquired and stored current values with respect to time; and
A voltage method calculation unit that calculates the amount of electricity stored by a voltage method that calculates the amount of electricity stored based on a correlation between the voltage value acquired by the measurement value acquisition unit and the amount of electricity stored;
A current stability determination unit that determines that the acquired current value is stable when the acquired current value is within a predetermined current value amplitude range within a predetermined time range ;
When the current stability determination unit determines that the current value is stable, the method for calculating the storage amount is switched from the current integration calculation method to the voltage method,
After the current stability determination unit determines that the current value is stable, and after the determination unit determines whether or not the current value is stable, A storage amount calculation method switching unit for switching from calculation of the storage amount by the voltage method to calculation of the storage amount by the current integration calculation method;
Have
The measurement value acquisition unit further has a function of detecting the temperature of the power storage device from a temperature detection unit,
The current value amplitude range becomes smaller as the temperature of the power storage device decreases.
The power storage amount calculation device is characterized in that the time range is set to become longer as the temperature of the power storage device decreases . The determination unit
After switching the calculation method of the charged amount to the voltage method, the first current value detected by the current value detection unit and the current value detected before the first current value are stored in the storage unit. The slope of the change in current value is calculated by dividing the difference from the second current value by the time from the time of detection of the second current value to the time of detection of the first current value,
When the calculated slope of the current value change is larger than a predetermined value, it is determined that the current value is not stable.
The power storage amount calculation apparatus according to claim 1, wherein: In the storage amount calculation device, the relationship between the upper limit storage amount of the storage device and the voltage value, and the relationship between the lower limit storage amount and the voltage value are input in advance,
When the voltage value is equal to the voltage value indicating the upper limit storage amount, the upper limit storage amount is the storage amount of the power storage device,
The voltage value is equal to the voltage value indicating the lower limit accumulation amount, claim 1 or claim, characterized by further having a lower limit accumulation amount calculating section on the lower limit storage amount and storage amount of the electrical storage device storage amount calculation apparatus described in 2. When switching the method of calculating the amount of electricity stored in the electricity storage device,
Comparing the calculated first power storage amount with the second power storage amount calculated before the calculation of the first power storage amount;
When the difference between the first power storage amount and the second power storage amount is larger than a predetermined value,
Performing a change-over process for gradually changing the amount of electricity stored from the second amount of electricity stored to the first amount of electricity stored;
When switching from the voltage method to the current integration calculation method occurs during the transfer process,
The storage amount calculation device according to any one of claims 1 to 3 , further comprising a change-over processing unit that integrates the current value from the storage amount at the time of the switching. A storage amount calculation method in a storage amount calculation device for calculating a storage amount of a storage device that supplies power to a load, comprising:
The power storage amount calculation device includes:
While acquiring the voltage value in the power storage device detected by the voltage value detection unit and the current value in the power storage device detected by the current value detection unit , the temperature of the power storage device is detected from the temperature detection unit,
Storing the acquired current value;
The current value amplitude set such that the acquired current value becomes smaller as the temperature of the power storage device decreases within a time range that is set longer as the temperature of the power storage device decreases. When it falls within the range, it is determined that the acquired current value is stable ,
If the current value is determined to be stable, the pre-Symbol acquisition and the stored current values, from the current integration calculation method for calculating the charged amount by integrating with respect to time, a voltage value the acquired, the storage amount Based on the correlation, the method for calculating the amount of electricity storage is switched to the voltage method for calculating the amount of electricity storage ,
After the current value is determined to have stabilized, when the current value is determined not to be stable, from the storage amount of calculation by the voltage method, the to the storage amount of calculation by the current integration calculation method A method for calculating an amount of electricity stored, wherein the method for calculating the amount of electricity stored is switched. The power storage amount calculation device includes:
After switching the calculation method of the charged amount to the voltage method, the first current value detected by the current value detection unit and the current value detected before the first current value are stored in the storage unit. The slope of the change in current value is calculated by dividing the difference from the second current value by the time from the time of detection of the second current value to the time of detection of the first current value,
When the slope of the calculated current value change is larger than a predetermined value, it is determined that the current value is not stable.
The power storage amount calculation method according to claim 5.

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