JPWO2019116815A1 - Secondary battery monitoring device, secondary battery status calculation device and secondary battery status estimation method - Google Patents

Abstract

No measures have been taken to increase the error in the internal resistance of the secondary battery in the low temperature range, the error in the internal resistance in the low temperature range increases, and the accuracy of estimating the state of the secondary battery also deteriorates. When the temperature of the battery 100 is equal to or less than a predetermined value, the temperature correction unit 311 refers to the correspondence between the battery temperature T stored in the storage unit 320 and the temperature correction value α, and the battery 100 measured by the measurement unit 200. The temperature correction value α corresponding to the battery temperature T is read out, the temperature correction value α is added to the battery temperature T, and the temperature correction value α is output to the internal resistance calculation unit 312.

Description

The present invention relates to a secondary battery monitoring device, a secondary battery status calculation device, and a secondary battery status estimation method.

In order to use secondary batteries safely and effectively in power supply devices, distributed power storage devices, and electric vehicles that use secondary batteries such as lithium secondary batteries, nickel-hydrogen batteries, lead batteries, and electric double-layer capacitors. , The state of the secondary battery is estimated. The state of the secondary battery is the internal resistance of the secondary battery, the state of charge (SOC: State of Charge) or the remaining capacity, which indicates how much the battery is charged or how much charge is left to be discharged. , There is a state of health (SOH) indicating the degree of deterioration or weakness, or the degree of deterioration. Based on the state of these secondary batteries, the permissible power and the permissible current, which are indicators of how much output can be output from the secondary battery, are derived.

Since the internal resistance of the secondary battery is used to estimate the state of the secondary battery, it is important to accurately detect and estimate this. Generally, in the relationship between internal resistance and temperature, the lower the temperature, the higher the internal resistance tends to be, and the lower the temperature, the higher the rate of increase of the internal resistance, and when searching for the internal resistance from the temperature, the error of the internal resistance increases. There is a tendency. Patent Document 1 describes that the temperature is corrected based on the internal resistance-temperature characteristic data of the secondary battery and the temperature measured by the temperature sensor.

Japanese Unexamined Patent Publication No. 2001-228226

The technique described in Patent Document 1 does not take measures against the expansion of the error of the internal resistance of the secondary battery in the low temperature region, the error of the internal resistance in the low temperature region expands, and eventually the accuracy of the state estimation of the secondary battery. Also gets worse.

The secondary battery monitoring device according to the present invention includes a temperature measuring unit for measuring the temperature of the secondary battery and a secondary battery state calculation device, and the secondary battery state calculation device includes the temperature and internal resistance of the secondary battery. A storage unit that stores the correspondence between the above, a temperature correction unit that adds a temperature correction value α to the battery temperature T measured by the temperature measurement unit, and derives a correction temperature T _α, and a temperature correction unit derived from the temperature correction unit. State estimation that estimates the state of the secondary battery based on the internal resistance calculation unit that obtains the internal resistance corresponding to the correction temperature T _α with reference to the storage unit and the internal resistance obtained by the internal resistance calculation unit. It includes a control unit.
The secondary battery state calculation device according to the present invention has a storage unit that stores the correspondence between the temperature of the secondary battery and the internal resistance, and adds the temperature correction value α to the measured battery temperature T to obtain the correction temperature T _α . A temperature correction unit to be derived, an internal resistance calculation unit for obtaining the internal resistance corresponding to the correction temperature T _α derived by the temperature correction unit with reference to the storage unit, and an internal resistance calculation unit obtained by the internal resistance calculation unit. It includes a state estimation control unit that estimates the state of the secondary battery based on the resistance.
In the secondary battery state estimation method according to the present invention, the correspondence between the temperature of the secondary battery and the internal resistance is stored, and the temperature correction value α is added to the measured battery temperature T to derive the correction temperature T _α . The internal resistance corresponding to the derived correction temperature T _α is obtained by referring to the correspondence between the stored secondary battery temperature and the internal resistance, and the state of the secondary battery is obtained based on the obtained internal resistance. Make an estimate.

According to the present invention, it is possible to reduce the error of the internal resistance of the secondary battery in the low temperature range and improve the accuracy of the state estimation of the secondary battery.

It is a block block diagram of the secondary battery monitoring device. It is a block block diagram of the secondary battery state arithmetic unit. It is a figure which shows the relationship between a battery temperature and an internal resistance. It is a figure which shows the relationship between a battery temperature and an internal resistance error. It is a figure which shows the relationship between a battery temperature, a correction temperature, and an internal resistance error. It is a figure which shows the relationship between the temperature correction value and the internal resistance error at a battery temperature of 25 degreeC. It is a figure which shows the relationship between the temperature correction value and an internal resistance error at a battery temperature of 35 degreeC. It is a figure which shows the relationship between the temperature correction value and the internal resistance error at a battery temperature of 45 degreeC.

FIG. 1 is a block configuration diagram of the secondary battery monitoring device 1000 according to the present embodiment. The secondary battery monitoring device 1000 includes a battery 100, a measuring unit 200, a battery state calculation device 300, and an output unit 400. The electric charge stored in the battery 100 is supplied to an external device as electric power, and the target for supplying the electric power may be, for example, an electric vehicle, a hybrid vehicle, or a train. The battery state arithmetic unit 300 outputs the charge state SOC of the battery 100, the deterioration degree SOH, and the like to the output unit 400.

The battery 100 is a rechargeable battery such as a lithium ion secondary battery. In addition, the present embodiment can be applied to devices having a power storage function such as nickel-metal hydride batteries, lead batteries, and electric double-layer capacitors. The battery 100 may be a cell or a modular structure in which a plurality of cell cells are combined.

The measuring unit 200 is a functional unit that measures the physical characteristics of the battery 100, for example, the voltage V across the battery 100, the current (battery current) I flowing through the battery 100, the battery temperature T of the battery 100, and the like, and measures each value. It consists of a sensor and necessary electric circuits. A measuring means such as a thermistor, a thermocouple, or an infrared ray is used to measure the battery temperature T. In any of the measuring means, the battery temperature of the measurement result includes the device-specific measurement error value β. ..

The battery state calculation device 300 is a device that estimates the state of the battery 100, and includes a battery state estimation device 310 and a storage unit 320. As will be described later, the internal resistance value R of the battery 100 is required to estimate the state of the battery 100, but in the present embodiment, the internal resistance value R is determined by using other measurement parameters in the battery state estimation device 310. calculate.

The battery state estimation device 310 is stored in the storage unit 320 based on the voltage V across the battery 100 measured by the measuring unit 200, the battery current I flowing through the battery 100, and the battery temperature T of the battery 100. The SOC and SOH of the battery 100 are calculated with reference to the characteristic information of. The calculation of the internal resistance R of the battery 100 and the calculation of SOC and SOH will be described later.

The battery state estimation device 310 can be configured by using hardware such as a circuit device that realizes the function. Further, the software that implements the function can be configured by executing the software such as a CPU (Central Processing Unit). In the latter case, the software is stored, for example, in the storage unit 320.

The storage unit 320 stores characteristic information of the battery 100 that can be known in advance, such as the internal resistance R of the battery 100, the polarization voltage, the charging efficiency, the allowable current, and the battery capacity. In this embodiment, the correspondence between the battery temperature and the internal resistance is stored in the form of a correspondence table, a function formula, or the like. Further, as will be described later, the correspondence between the battery temperature and the temperature correction value is stored. The values of these characteristic information may be individually stored for each charging / discharging operation, or the values may be individually stored for each state of the battery 100 such as the charging state and the battery temperature.

The storage unit 320 is configured by using a storage device such as a flash memory, an EEPROM (Electrically Erasable Programmable Read-Only Memory), and a magnetic disk. The storage unit 320 may be provided outside the battery state estimation device 310, or may be realized as a memory device provided inside the battery state estimation device 310. The storage unit 320 may be removable. When made removable, the characteristic information and software can be easily changed by replacing the storage unit 320. Further, by having a plurality of storage units 320 and storing the characteristic information and the software in the replaceable storage units 320 in a distributed manner, the characteristic information and the software can be updated in small units.

The output unit 400 is a functional unit that outputs the output of the battery state calculation device 300 to an external device (for example, a higher-level device such as a vehicle control device included in an electric vehicle).

FIG. 2 is a block configuration diagram of a battery state calculation device 300 including a battery state estimation device 310 and a storage unit 320.
The battery state estimation device 310 includes a temperature correction unit 311, an internal resistance calculation unit 312, an SOC calculation unit 313, and a SOH calculation unit 314.

When the temperature of the battery 100 is equal to or less than a predetermined value, the temperature correction unit 311 adds the temperature correction value α to the battery temperature T measured by the measurement unit 200 and sends the correction temperature T _α to the internal resistance calculation unit 312. Output. The temperature correction value α is a value within the range of the measurement error value β of the temperature measurement by the sensor of the measurement unit 200. The measurement error value β is a value peculiar to the sensor used in the measurement unit 200, and is a value that is known in advance. The derivation of the optimum temperature correction value α will be described later. Further, when the temperature of the battery 100 is not equal to or lower than a predetermined value, the temperature compensation unit 311 outputs the battery temperature T measured by the measurement unit 200 to the internal resistance calculation unit 312 as it is.

When the temperature of the battery 100 is equal to or lower than a predetermined value, the internal resistance calculation unit 312 sets the internal resistance corresponding to the obtained correction temperature T _α to the temperature in the storage unit 320 and the internal resistance. Find by referring to the relationship. Further, when the temperature of the battery 100 is not equal to or lower than a predetermined value, the internal resistance calculation unit 312 sets the internal resistance corresponding to the battery temperature T measured by the measuring unit 200 between the temperature in the storage unit 320 and the internal resistance. Obtain by referring to the correspondence. The obtained internal resistance is output to the SOC calculation unit 313 and the SOH calculation unit 314.

When the temperature of the battery 100 is equal to or less than a predetermined value, it is converted into a value of internal resistance with less error by the temperature correction unit 311 and the internal resistance calculation unit 312, and this value is used. The errors in the calculations of the SOC calculation unit 313 and the SOH calculation unit 314 are also reduced.

An example of the calculation of the SOC calculation unit 313 and the SOH calculation unit 314 will be described below.
The SOC calculation unit 313 obtains the SOC, and there are various methods for the SOC, and the first method will be described below.

The voltage V across the battery 100, the current (battery current) I flowing through the battery 100, the battery temperature T of the battery 100, and the like are input to the SOC calculation unit 313. The SOC calculation unit 313 calculates and outputs the SOC based on the integrated value of the current based on the input current and the previous value (calculation result of one cycle before) of the SOC calculation result by the SOC calculation unit 313. The SOC is calculated by, for example, the following equation (1). In equation (1), SOCold is the previous value of SOC. Further, ΔSOC is the amount of change in SOC due to the current I flowing from the previous calculation to the current calculation, Qmax is the full charge capacity of the battery 100, and ts is the control cycle (sampling cycle of current, voltage, etc.). Is.
SOC = SOCold + ΔSOC… (1)
However, ΔSOC = 100 × I × ts / Qmax.

In this way, the SOC calculation unit 313 integrates the discharge current from the full charge based on the equation (1), and the amount of charge remaining in the battery 100 with respect to the maximum chargeable amount (total capacity). The ratio of (residual capacity) is calculated to obtain the SOC.

Next, a second method for obtaining the SOC by the SOC calculation unit 313 will be described.
In general, the battery 100 can be represented by a parallel connection pair of impedance Z and capacitance component C, an internal resistance R, and a series connection of an open circuit voltage OCV. When the battery current I is applied to the battery 100, the closed circuit voltage CCV, which is the voltage between the terminals of the battery 100, is represented by the following equation (2). In the formula (2), Vp is a polarization voltage and corresponds to the voltage across the parallel connection pair of the impedance Z and the capacitance component C.
CCV = OCV + IR + Vp ... (2)

Although the open circuit voltage OCV is used to calculate the SOC, it cannot be directly measured while the battery 100 is charged and discharged. Therefore, the SOC calculation unit 313 obtains the open circuit voltage OCV by subtracting the IR drop and the polarization voltage Vp from the closed circuit voltage CCV as in the following equation (3).
OCV = CCV-I ・ R-Vp ・ ・ ・ (3)

The internal resistance R and the polarization voltage Vp are stored in the storage unit 120 in advance as characteristic information of the battery 100. Since the internal resistance R and the polarization voltage Vp differ depending on the state of charge of the battery 100, the battery temperature, and the like, individual values are stored in the storage unit 120 for each combination of these. In the present embodiment, the storage unit 120 is referred to by using the internal resistance R obtained by the internal resistance calculation unit 312. Then, the IR drop is obtained by using the internal resistance R obtained by the internal resistance calculation unit 312.

Further, the correspondence between the open circuit voltage OCV of the battery 100 and the SOC is determined by the characteristics of the battery 100, and the storage unit 120 stores in advance the data defining the correspondence as an SOC table. The SOC calculation unit 313 calculates the open circuit voltage OCV using the above equation (3), and calculates the SOC of the battery 100 by referring to the SOC table using this as a key.

As described above, the current SOC can be obtained by the first method and the second method. Furthermore, the SOC may be obtained by weighting and adding to the SOC obtained by these methods.

The SOH calculation unit 314 calculates SOH by, for example, the following equation (4) based on the initial internal resistance value R0 corresponding to the SOC and the temperature and the current internal resistance value R. In this embodiment, the value of the internal resistance R obtained by the internal resistance calculation unit 312 is used.
SOH = 100 × R / R0… (4)
The initial internal resistance value R0 corresponds to the battery 100 and is stored in advance in the storage unit 320. Normally, the SOH calculation unit 314 updates and outputs the calculation based on the equation (4) at predetermined cycles such as a control cycle (sampling cycle of current, voltage, etc.).

The SOC calculation unit 313 and the SOH calculation unit 314 show typical examples used in the secondary battery control device in the present embodiment, but the present invention is not limited to these, and other calculations are added. It may have other configurations.

Next, the internal resistance of the battery 100 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a diagram showing the relationship between the battery temperature of the battery 100 and the internal resistance. In FIG. 3, the horizontal axis represents temperature and the vertical axis represents internal resistance. As shown in FIG. 3, the higher the battery temperature is T _{HIGH, the} smaller the internal resistance is R _THIGH , and the lower the temperature is T _{LOW, the} larger the internal resistance is R _TLOW .

FIG. 4 is a diagram showing the relationship between the battery temperature and the internal resistance error, and shows the degree of influence of the measurement error of the battery temperature T on the calculation result of the internal resistance R. A value measured by the measuring unit 200 is used as the battery temperature T, and the measurement result includes a measurement error β. When the temperature of the battery 100 is T _HIGH , the temperature ranges from _{TH 1} to TH 2 when the measurement error β by the measuring unit 200 is taken into consideration. At this time, the range that the internal resistance R can take is from R _TH1 to R _TH2 . On the other hand, when the temperature of the battery 100 is T _LOW , the temperature is in the range of _{TL 1} to TL 2 when the measurement error β by the measuring unit 200 is taken into consideration. At this time, the range that the internal resistance R can take is from R _TL1 to R _TL2 .

The calculation error E _RTHIGH of the internal resistance R when the battery temperature T is high T _HIGH is E _RTHIGH = R _TH1- R _TH2 , and the calculation error E _RTHLOW of the internal resistance R when the battery temperature T is low T _LOW is E _RTLLOW = R _TL1- R _TL2 . At this time, the relationship between the two calculation errors is E _RTLOW > E _{RT HIGH} , and it can be seen that the lower the battery temperature T, the larger the calculation error of the internal resistance R.

Next, the temperature correction by the temperature correction unit 311 will be described with reference to FIG.
FIG. 5 is a diagram showing the relationship between the battery temperature, the correction temperature, and the internal resistance error. Figure 5 shows an example, and the internal R _T resistor corresponding to the battery temperature T, and an internal resistance R _{T [alpha} corresponding to the temperature T _alpha performing the correction of adding temperature correction value alpha to the battery temperature T.

Further, when the actual battery temperature of the battery 100 is T _C, the battery temperature T measured by the measuring unit 200 includes a measurement error beta. Therefore, the temperature range is in the range of T ₁ to T ₂ when the measurement error β is taken into consideration. That is, the range from T ₁ to T ₂ is within the range of the measurement error β. At this time, the original internal resistance is _RT , but the internal resistance calculated due to the influence of the temperature measurement error is in the range of _RT1 to _RT2 .

In the present embodiment, it is assumed that the temperature correction unit 311 intentionally adds the temperature correction value α to the battery temperature T, and the added battery temperature is T _α . The temperature correction value α is a value within the range of the measurement error value β of the temperature measurement by the sensor of the measurement unit 200. At this time, although the internal resistance becomes R _{T [alpha,} internal resistance calculated by the influence of the temperature measurement error in the range of R _{T [alpha] 1} of _R Tα2.

As described with reference to FIG. 4, the higher the battery temperature T, the smaller the error in the internal resistance R. Therefore, as shown in FIG. 5, the range _{E RT} can take the error of the internal resistance R of the battery temperature T, when comparing the range _{E RTarufa} can take the internal resistance error in the temperature _T α _{E RT> E RTα} next, By adding the temperature correction value α to the battery temperature T, the error of the internal resistance R becomes smaller. However, since the temperature correction unit 311 corrects the actually measured battery temperature T by adding the temperature correction value α, _DR0 (= _RT −R _Tα ) with respect to the original _RT . Only the internal resistance error increases.
Accordingly interior by performing temperature correction to the extent that increases towards the smaller internal resistance error _{D R1 (= E RT -E RTα} ) and increases the internal resistance error _{D R0} by comparing _{D R1} by performing the temperature correction The resistance error can be reduced. A value satisfying this condition is set for the temperature correction value α.

The storage unit 320 stores the correspondence between the temperature and the internal resistance, and the temperature correction value α that reduces the internal resistance error as described above is stored in advance based on the correspondence between the temperature and the internal resistance. ing. The temperature correction unit 311 reads out the temperature correction value α, adds the temperature correction value α to the battery temperature T measured by the measurement unit 200, and outputs the correction temperature T _α to the internal resistance calculation unit 312.

Next, the temperature correction value α corrected by the temperature correction unit 311 will be described with reference to FIGS. 6 to 8.
In the four line graphs shown in FIGS. 6 to 8, the temperature of the battery 100 is 25 ° C., 35 ° C., and 45 ° C., and the battery temperature T measured by the measuring unit 200 is 25 ° C., 35 ° C., and 45 ° C., respectively. The internal resistance error when the temperature correction value α is set to 0 to 2.0 when the error of 0 ° C., 1 ° C., 2 ° C., and 3 ° C. is included with respect to the temperature is shown.

FIG. 6 is a diagram showing the relationship between the temperature correction value α and the internal resistance error when the temperature of the battery 100 is 25 ° C. In actual temperature T _C of the battery 100 is 25 ° C., if the temperature T measured by the measuring section 200 is T _{C +} 3 ° C., ie, if it contains a measurement error of 3 ° C., the line graph of black circles in FIG. 6 As shown by, the internal resistance error can be reduced as the temperature correction value α is increased to 0.5 ° C. and 1 ° C. as compared with the case where the temperature correction is not performed (α = 0). However, if the temperature correction value α is further increased from 1.0 ° C., the internal resistance error becomes larger. As described above, the temperature correction value α has a range in which the internal resistance error is minimized.

Polyline black triangle in FIG. 6, when the temperature T measured by the measuring section 200 is T _{C +} 2 ° C., that is, if it contains a measurement error of 2 ° C.. Polyline filled squares in Figure 6, when the temperature T measured by the measuring section 200 is T _{C +} 1 ° C., that is, if it contains a measurement error of 1 ° C.. Polyline black diamonds in FIG. 6, when the temperature T measured by the measuring section 200 is T _C ° C., that is, if it contains a measurement error of 0 ° C.. That is, it can be seen that the internal resistance error can be reduced by increasing the temperature correction value α as the measurement error increases.

FIG. 7 is a diagram showing the relationship between the temperature correction value α and the internal resistance error when the temperature of the battery 100 is 35 ° C. Again, the actual temperature T _C of the battery 100 is 35 ° C., if the temperature T measured by the measuring section 200 is T _{C +} 3 ° C., the temperature correction value as represented by a line graph of filled circles α The internal resistance error is the smallest when the temperature is 1.5 ° C.

FIG. 8 is a diagram showing the relationship between the temperature correction value α and the internal resistance error when the temperature of the battery 100 is 45 ° C. In this case, the actual temperature T _C of the battery 100, irrespective of the error between the magnitude of the temperature T measured by the measuring unit 200, by performing the temperature correction, the internal resistance error is large. As explained with reference to FIG. 4, the higher the battery temperature, the smaller the influence of the internal resistance error on the temperature measurement error. Therefore, the influence of the expansion of the internal resistance error due to the temperature correction is obtained. This is because it is larger.

From these facts, for example, when the measured battery temperature T is 30 ° C. or lower, the temperature correction value α is set to 1 ° C., and when the battery temperature T is 30 ° C. to 40 ° C., the temperature correction value α is set to 1. The temperature is 5 ° C. When the battery temperature T is 40 ° C. or higher, the temperature correction value α is set to 0 ° C., or the temperature correction is not performed. As a result, the reduction of the internal resistance error due to the temperature correction can be effectively utilized. The storage unit 320 stores the correspondence between the battery temperature T and the temperature correction value α.

The temperature correction unit 311 refers to the correspondence relationship between the battery temperature T stored in the storage unit 320 and the temperature correction value α, and sets the temperature correction value α corresponding to the battery temperature T of the battery 100 measured by the measurement unit 200. Read out, add the temperature correction value α to the battery temperature T, and output to the internal resistance calculation unit 312. The threshold value such as temperature exemplified in this embodiment is not limited to that value, and an optimum value is set according to the characteristics of the device involved in the calculation, such as the characteristics of the battery 100 and the measurement error of the measuring unit 200. Shall be selected.

According to the present embodiment, the internal resistance derived by the internal resistance calculation unit 312 is obtained by adding the temperature correction value α corresponding to the battery temperature T to the battery temperature T measured by the measuring unit 200. The error can be reduced. Further, the calculation of the SOC calculation unit 313 and the SOH calculation unit 314 using the internal resistance also has less error.

According to the embodiment described above, the following effects can be obtained.
(1) The secondary battery monitoring device 1000 includes a measuring unit 200 that measures the temperature of the battery 100, and a secondary battery state calculation device 300 that calculates the state of the battery 100. The secondary battery state calculation device 300 has a storage unit 320 that stores the correspondence between the temperature of the battery 100 and the internal resistance, and a correction temperature T by adding a temperature correction value α to the battery temperature T measured by the measurement unit 200. _The temperature correction unit 311 for deriving _α , the internal resistance calculation unit 312 for obtaining the internal resistance corresponding to the correction temperature T _α derived by the temperature correction unit 311 with reference to the storage unit 320, and the internal resistance calculation unit 312 for obtaining the internal resistance. It includes an SOC calculation unit 313 and a SOH calculation unit 314 that estimate the state of the battery 100 based on the obtained internal resistance. The SOC calculation unit 313 and the SOH calculation unit 314 are elements that constitute the battery state estimation device 310. As a result, the error of the internal resistance of the secondary battery in the low temperature range can be reduced, and the accuracy of the state estimation of the secondary battery can be improved.

(2) In the secondary battery monitoring device 1000, the storage unit 320 stores the correspondence relationship between the battery temperature T and the temperature correction value α, and the temperature correction unit 311 corresponds to the battery temperature T measured by the measurement unit 200. The temperature correction value α to be measured is obtained by referring to the correspondence between the battery temperature T stored in the storage unit 320 and the temperature correction value α. As a result, the battery temperature T can be associated with the temperature correction value α, the error in the internal resistance of the secondary battery in the low temperature range can be reduced, and the accuracy of estimating the state of the secondary battery can be improved.

(3) The temperature correction unit 311 uses the temperature correction value α as the battery temperature T measured by the measurement unit 200, the resistance value _RT corresponding to the battery temperature T obtained by the internal resistance calculation unit 312, and the battery temperature T. Difference between the correction temperature T _{α, which} is higher than the temperature correction value α by _α, and the resistance value R _{T α} corresponding to the temperature higher than the battery temperature T obtained from the internal resistance calculation unit 312 by the temperature correction value α α D _R0 (= _RT − R _Tα ), two temperatures T _{1 and} T ₂ shifted up and down from the battery temperature T by a predetermined value (temperature measurement error of the measuring unit 200), and two temperatures T ₁ obtained by the internal resistance calculation unit 312 _. The difference _ER T between the two resistance values corresponding to T ₂ and the two temperatures shifted up and down by a predetermined value (temperature measurement error of the measuring unit 200) from the corrected temperature T _{α, which is} higher than the battery temperature T by the temperature correction value α. T _{[alpha] 1,} T _{[alpha] 2} and the internal resistance computing unit 312 in the two temperatures T _{[alpha] 1} obtained, the difference _{D R1 (= E RT -E RTα} ) is greater towards the difference _{E RTarufa} the two resistance values corresponding to T _{[alpha] 2} The temperature correction value α is used. As a result, the optimum temperature correction value α can be set, the error in the internal resistance of the secondary battery in the low temperature range can be reduced, and the accuracy of the state estimation of the secondary battery can be improved.

(4) In the secondary battery monitoring device 1000, the temperature correction value α is within the range of the temperature measurement error of the measuring unit 200. Thereby, within the range of the temperature measurement error of the measuring unit 200, the error of the internal resistance of the secondary battery in the low temperature range can be reduced, and the accuracy of the state estimation of the secondary battery can be improved.

(5) The secondary battery state calculation device 300 includes a storage unit 320 that stores the correspondence between the temperature of the secondary battery and the internal resistance, and a battery state estimation device 310. Battery state estimating unit 310 includes a temperature compensation unit 311 for deriving the correction temperature T _alpha by adding the temperature correction value alpha to the measured battery temperature T, corresponding to the correction temperature T _alpha derived by the temperature correction unit 311 The internal resistance calculation unit 312 for obtaining the internal resistance with reference to the storage unit, and the SOC calculation unit 313 and the SOH calculation unit 314 for estimating the state of the secondary battery based on the internal resistance obtained by the internal resistance calculation unit 312. To be equipped.

(6) When the battery temperature T is not equal to or lower than a predetermined value, the internal resistance calculation unit 312 stores the internal resistance corresponding to the measured battery temperature T as the secondary battery temperature T and the internal resistance stored in the storage unit 320. Obtained by referring to the correspondence of.

(7) The secondary battery state estimation method stores the correspondence between the temperature of the battery 100 and the internal resistance, adds the temperature correction value α to the measured battery temperature T, and derives the correction temperature T _α. The internal resistance corresponding to the corrected correction temperature T _α is obtained by referring to the correspondence between the stored temperature of the battery 100 and the internal resistance, and the state of the battery 100 is estimated based on the obtained internal resistance. As a result, the error of the internal resistance of the secondary battery in the low temperature range can be reduced, and the accuracy of the state estimation of the secondary battery can be improved.
(8) In the secondary battery state estimation method, when the battery temperature T is not equal to or lower than a predetermined value, the internal resistance corresponding to the measured battery temperature T is the correspondence between the stored secondary battery temperature and the internal resistance. To find it by referring to.

(Modification example)
The present invention can be implemented by modifying the embodiment described above as follows.
(1) In the embodiment, an example has been described in which the temperature range for temperature correction and the temperature correction value α are predetermined and stored in the storage unit 320. However, instead of defining these in advance, the battery state estimation device 310 calculates the temperature correction value α, which minimizes the internal resistance error, in real time while changing the temperature correction value α in various ways, and obtains this by calculating the temperature correction value α. May be.

The present invention is not limited to the above-described embodiment, and other embodiments considered within the scope of the technical idea of the present invention are also included within the scope of the present invention as long as the features of the present invention are not impaired. ..

100 ... Battery 200 ... Measuring unit 300 ... Battery state calculation device 310 ... Battery state estimation device 311 ... Temperature correction unit 312 ... Internal resistance calculation unit 313 ... SOC calculation unit 314 ... SOH calculation unit 320 ... Storage unit 400 ... Output unit 1000 ... Secondary battery monitoring device

Claims (9)

A secondary battery monitoring device having a temperature measuring unit for measuring the temperature of a secondary battery and a secondary battery status calculation device for calculating the state of the secondary battery.
The secondary battery state arithmetic unit is
A storage unit that stores the correspondence between the temperature of the secondary battery and the internal resistance,
A temperature correction unit that derives the correction temperature T _α by adding the temperature correction value α to the battery temperature T measured by the temperature measurement unit, and
An internal resistance calculation unit for obtaining an internal resistance corresponding to the corrected temperature T _α derived by the temperature correction unit with reference to the storage unit,
A state estimation control unit that estimates the state of the secondary battery based on the internal resistance obtained by the internal resistance calculation unit, and a state estimation control unit.
Secondary battery monitoring device equipped with. In the secondary battery monitoring device according to claim 1,
The storage unit stores the correspondence between the battery temperature T and the temperature correction value α.
The temperature correction unit refers to the correspondence relationship between the battery temperature T and the temperature correction value α in which the temperature correction value α corresponding to the battery temperature T measured by the temperature measurement unit is stored in the storage unit. Secondary battery monitoring device to be sought. In the secondary battery monitoring device according to claim 1 or 2.
The temperature correction unit sets the temperature correction value α as
The battery temperature T measured by the temperature measuring unit, the resistance value _RT corresponding to the battery temperature T obtained by the internal resistance calculation unit, and the corrected temperature T _{α which is} higher than the battery temperature T by a temperature correction value α _α. And the difference D _R0 (= _RT- R _Tα ) from the resistance value R _Tα corresponding to the temperature obtained from the internal resistance calculation unit and the temperature correction value α higher than the battery temperature T.
Difference E _RT between _two temperatures T _{1 and} T ₂ shifted up and down from the battery temperature T by a predetermined value and two resistance values corresponding to the two temperatures T _{1 and} T ₂ obtained by the internal resistance calculation unit. Two temperatures T _{α1 and} T _α2 that are shifted up and down by a predetermined value from the correction temperature T _{α that is} higher than the battery temperature T by a temperature correction value α _α , and the two temperatures T _α1 obtained by the internal resistance calculation unit _. difference _{D R1 (= E RT -E RTα} ) secondary battery monitoring device using a temperature correction value α which becomes larger towards the difference _{E RTarufa} two corresponding resistance value T _{[alpha] 2.} In the secondary battery monitoring device according to any one of claims 1 to 3.
The temperature correction value α is a secondary battery monitoring device within the range of the temperature measurement error of the temperature measuring unit. In the secondary battery monitoring device according to any one of claims 1 to 4.
When the battery temperature T is not equal to or lower than a predetermined value, the internal resistance calculation unit stores the internal resistance corresponding to the measured battery temperature T as the correspondence between the temperature of the secondary battery stored in the storage unit and the internal resistance. Secondary battery monitoring device obtained by referring to the relationship. A storage unit that stores the correspondence between the temperature of the secondary battery and the internal resistance,
A temperature compensation unit that derives the correction temperature T _α by adding the temperature correction value α to the measured battery temperature T,
An internal resistance calculation unit for obtaining an internal resistance corresponding to the corrected temperature T _α derived by the temperature correction unit with reference to the storage unit,
A state estimation control unit that estimates the state of the secondary battery based on the internal resistance obtained by the internal resistance calculation unit, and a state estimation control unit.
Secondary battery state arithmetic unit equipped with. In the secondary battery state arithmetic unit according to claim 6.
When the battery temperature T is not equal to or lower than a predetermined value, the internal resistance calculation unit stores the internal resistance corresponding to the measured battery temperature T as the correspondence between the temperature of the secondary battery stored in the storage unit and the internal resistance. A secondary battery state calculation device obtained by referring to the relationship. Memorize the correspondence between the temperature of the secondary battery and the internal resistance,
The temperature correction value α is added to the measured battery temperature T to derive the correction temperature T _α .
The internal resistance corresponding to the derived correction temperature T _α is obtained by referring to the correspondence relationship between the stored secondary battery temperature and the internal resistance.
The state of the secondary battery is estimated based on the obtained internal resistance.
Secondary battery state estimation method. In the secondary battery state estimation method according to claim 8,
When the battery temperature T is not equal to or lower than a predetermined value, the secondary battery state in which the internal resistance corresponding to the measured battery temperature T is obtained by referring to the correspondence between the stored secondary battery temperature and the internal resistance. Estimating method.

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