JP5129029B2 - Open voltage value estimation method and open voltage value estimation apparatus - Google Patents

Description

  The present invention relates to an open-circuit voltage value estimation method and an open-circuit voltage value estimation device that estimate an open-circuit voltage value of a battery based on a voltage value of an in-vehicle battery measured before starting an engine.

In an automobile, when the engine is rotating, the engine's rotational force is converted into electric energy by an on-vehicle generator, the generated electric power is supplied to various loads, and the battery is charged using surplus electric power. Is going.
The automobile engine is started by driving a starter. When the starter is driven, a large voltage drop due to an inrush current is involved, so that a sufficient starting voltage needs to be supplied from the battery. Therefore, it is important to accurately manage the state of charge of the battery so that the engine can be started by driving the starter.

In general, the open-circuit voltage value of the battery after completion of charging decreases with the elimination of the charge polarization caused by the charge, and becomes constant when the charge polarization is completely eliminated and the equilibrium state is reached. On the other hand, the open-circuit voltage value of the battery after the end of discharge rises with the elimination of the discharge polarization caused by the discharge, and becomes constant when the discharge polarization is completely eliminated and an equilibrium state is reached.
The open-circuit voltage value of the battery in the equilibrium state reflects the state of charge of the battery.

  Conventionally, in order to grasp the state of charge of a battery, an internal resistance is measured using a current sensor or the like, and an open circuit voltage value is estimated from a current-voltage relational expression.

  Patent Document 1 also calculated the difference between the pure resistance value determined based on the open circuit voltage-pure resistance characteristics in the static state of the battery and the current pure resistance value of the battery in the measured static state. An invention of a correction coefficient calculation method is disclosed that is divided by a pure resistance value and used as a correction coefficient for obtaining a state relating to the actual charge capacity of the battery. In this method, the state of charge of the battery is obtained in response to the deterioration of the battery and the fluctuation of the internal resistance due to temperature.

Furthermore, Patent Document 2 stores voltage data and current data when it is determined that the battery is in a predetermined discharge polarization state and the battery is not charged several seconds ago, and the number of stored data is a predetermined value. An invention of an internal resistance detection device is disclosed that calculates the internal resistance of a battery using stored data when the value exceeds.
JP 2002-303658 A JP 2004-31170 A

  As described above, the battery has a concentration distribution at the electrode interface when a current is flowing, but when charging or discharging is stopped, the voltage is applied until the concentration deviation is eliminated, that is, until the polarization is eliminated. Changes. Conventionally, since the open-circuit voltage value has been estimated at the stage where the charge polarization or discharge polarization has not been eliminated, a deviation from the true value has occurred. Using this open-circuit voltage value, the charging rate (SOC: State When obtaining a state of health (SOH) or a deterioration state (SOH: State Of Health), there is a problem that an error increases.

  Further, in the case of the invention according to Patent Document 2, since the data of the detected current and the detected voltage are selected according to the polarization index, there is a problem that the number of data when obtaining the internal resistance is reduced. Since the current sensor is used, there is a problem that the calculated internal resistance value varies depending on the accuracy and measurement timing of the current sensor.

  Further, an equation for estimating the voltage value of the polarization when the predetermined time has elapsed from the stop of the engine is obtained, and the open circuit voltage value is obtained by subtracting the voltage value of the polarization estimated by the estimation equation from the voltage value when the predetermined time has elapsed. Although there is a technology, in order to obtain the estimation formula, it is necessary to perform a large number of tests with different conditions such as a charging rate and a deterioration state, and the estimation formula is obtained in advance, There was a problem that it could not cope with the type and the degree of deterioration.

  The present invention has been made in view of such circumstances, and obtains an expression representing the relationship between the elapsed time from the engine stop and the voltage change amount (resolved polarization voltage value), and the voltage change amount when the second time elapses. By calculating the open-circuit voltage value based on the estimated voltage change amount and the voltage value at the time of the first time, it is possible to use a simple configuration without using a current sensor and a complicated equation for estimating the polarization voltage value. To provide an open-circuit voltage value estimation method and an open-circuit voltage value estimation apparatus that can accurately estimate an open-circuit voltage value in correspondence with each battery and that can accurately determine a charging rate and a deterioration state. With the goal.

  An open-circuit voltage value estimation method according to a first aspect of the present invention is an open-circuit voltage value estimation method for estimating an open-circuit voltage value of a battery charged by an in-vehicle generator that generates power in conjunction with an engine, and whether or not the engine has stopped. If the engine is determined to have stopped, the voltage values of the battery at three or more subsequent times including the appropriate first time after the engine stop are acquired and stored, and the first time is The difference value between the acquired voltage value and the voltage value acquired after the first time point is obtained, a relational expression between the time elapsed since the engine stop and the obtained difference value is obtained, and whether or not the engine has started If it is determined that the engine has started, the estimated difference value at the second time point after the engine start is obtained using the relational expression, and the voltage value acquired at the first time point and the estimated difference are obtained. Open circuit voltage based on the value And obtaining the.

  The open circuit voltage value estimation method according to a second aspect of the present invention is the first aspect of the present invention, wherein the estimated voltage value is obtained from the voltage value acquired at the first time point when the acquired voltage value decreases with time after the engine is stopped. The open circuit voltage value is obtained by subtracting the difference value.

  The open circuit voltage value estimation method according to a third aspect of the present invention is the first aspect of the present invention, in which the estimated voltage value acquired at the first time point is estimated when the acquired voltage value increases with time after the engine is stopped. The open circuit voltage value is obtained by adding the difference value.

  The open-circuit voltage value estimation method according to a fourth invention is characterized in that, in the first to third inventions, the temperature information is acquired and the first time point is determined based on the acquired temperature information.

  The open circuit voltage value estimation method according to a fifth aspect of the present invention is the fourth aspect of the present invention, wherein the voltage values of the battery at three or more time points after that including an appropriate first time point after engine stop are previously acquired for a plurality of temperatures. The difference value between the voltage value acquired at the first time point and the voltage value acquired after the first time point is obtained, and the relationship between the elapsed time from the engine stop and the obtained difference value is obtained. A table for determining the first time point based on the temperature information is created from the relationship for a plurality of temperatures, and the first time point is determined using the table based on the acquired temperature information. Features.

  An open-circuit voltage value estimation device according to a sixth aspect of the present invention is an open-circuit voltage value estimation device that estimates an open-circuit voltage value of a battery charged by an on-vehicle generator that generates power in conjunction with the engine, and whether or not the engine has stopped. First determining means for determining whether the engine has been stopped by the first determining means, and means for measuring the elapsed time after the engine is stopped, and whether the elapsed time is equal to or longer than the first time And a voltage value of the battery at three or more time points including the first time when the elapsed time is determined to be equal to or longer than the first time. , A storage means for storing the acquired voltage value, a means for obtaining a difference value between the voltage value acquired when the first time has elapsed and the voltage value acquired after the first time has elapsed, and the engine stop Has passed since And means for obtaining a relational expression between the obtained difference value, a third judgment means for judging whether or not the engine has started, and the relational expression when the third judgment means judges that the engine has been started. And means for obtaining an estimated difference value at the elapse of the second time after engine start, and means for obtaining an open-circuit voltage value based on the voltage value acquired at the time of the first time and the estimated difference value. It is characterized by that.

  An open-circuit voltage value estimation device according to a seventh invention is characterized in that, in the sixth invention, a means for detecting the temperature and a means for determining the first time based on the temperature detected by the means are provided.

In the present invention, for each battery, the amount of voltage drop during charging (the amount of drop from the voltage value when the first time elapses) or the amount of voltage rise during discharge (when the first time elapses) due to elimination of polarization. The amount of voltage drop or the amount of voltage rise when the second time elapses (resolved polarization) by learning the relationship between the voltage value of the resolved polarization and the elapsed time. Voltage value) can be calculated. The open-circuit voltage value is calculated by subtracting or adding the calculated voltage value from the voltage value at the time of the first time.
In addition, by determining the first time corresponding to the temperature, the equation indicating the relationship between the voltage value of the canceled polarization and the elapsed time can be approximated better, and the open-circuit voltage value can be estimated more accurately. can do.

According to the present invention, after a lapse of the first time from the engine stop, a voltage value is acquired with time, a relational expression between the elapsed time and the elimination polarization voltage value is obtained, and the elimination polarization voltage value at the second time elapse is obtained. presume. In the charging state, the elimination polarization voltage value is subtracted from the voltage value acquired when the first time has elapsed, and in the discharging state, the elimination polarization voltage value is added to the voltage value acquired when the first time has elapsed, and the open-circuit voltage value is obtained. Therefore, without using a current sensor, without using a complicated formula for estimating the polarization voltage, the open voltage value at the time when charge polarization or discharge polarization is eliminated can be accurately handled with a simple configuration, corresponding to each battery. It can be estimated well.
Therefore, when obtaining the charging rate or the deterioration state using this open-circuit voltage value, the accuracy is good.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a schematic configuration of a power supply control device 1 including an open-circuit voltage value estimation device 2 according to Embodiment 1 of the present invention.
The power supply control device 1 detects a battery (vehicle battery) 5, an open voltage value estimation device 2 that estimates an open voltage value of the battery 5, and an output voltage value (terminal voltage value) of the battery 5 to estimate an open voltage value And a voltage sensor 6 applied to the apparatus 2. The open-circuit voltage value estimation device 2 includes a microcomputer, and includes a processing unit 3 having a storage unit 31 and a timer 32, and an output unit 4. The output unit 4 is configured by, for example, a liquid crystal display device, and warns the user by displaying the open-circuit voltage value estimated by the processing unit 3 of the open-circuit voltage value estimation device 2.

When the ignition switch (hereinafter referred to as IG-SW) 7 is turned on, the battery 5 and the ignition device 8 are brought into conduction, and the starting operation of the engine 9 is started.
When the engine 9 is rotating, the alternator (alternator) 10 converts the rotational force of the engine 9 into electric power energy, the generated electric power is supplied to the load 11, and the surplus electric power is used for the battery 5. Charging is attempted.

Below, operation | movement of the process part 3 of the open circuit voltage value estimation apparatus 2 of the above-mentioned structure is demonstrated, referring the flowchart of FIG. 2 which shows it.
In the present embodiment, a case where the IG-SW 7 is in a charged state when the IG-SW 7 is turned off (a case where the acquired voltage value decreases with time) will be described.
First, the processing unit 3 determines whether or not the IG-SW 7 is turned off (S1). When it is determined that the IG-SW 7 is not turned off (S1: NO), the processing unit 3 returns the process to step S1.
When it is determined that the IG-SW 7 is turned off (S1: YES), the processing unit 3 causes the timer 32 to start measuring time (S2).

Next, the processing unit 3 determines whether or not the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S3). As the first time, a time longer than the time during which the voltage value corresponding to the charge polarization rapidly decreases is set. An example of the first time is 3600 seconds.
When it is determined that the elapsed time after the IG-SW 7 is turned off is less than the first time (S3: NO), the processing unit 3 returns the process to step S3.

  When the processing unit 3 determines that the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S3: YES), the voltage sensor 6 acquires a voltage value from the first time at a predetermined sampling period. (S4) The acquired voltage value is stored in the storage unit 31 (S5). An example of the sampling period is 10 seconds.

FIG. 3 is a graph showing the relationship between the elapsed time from the turn-off of the IG-SW 7 and the voltage value.
In FIG. 3, when the elapsed time is less than 3600 seconds, it can be seen that the voltage value drops rapidly.

The processing unit 3 calculates a resolved polarization voltage value (a resolved polarization voltage value) obtained by subtracting the acquired voltage value from the voltage value acquired when the first time has elapsed (S6).
The processing unit 3 plots the obtained (elapsed time, elimination polarization voltage value), obtains the coefficients (α, β) by fitting using the following equation (1) using a Kalman filter (for example, the least square method), The relational expression is established (S7).
ΔV = α × ln (t) + β (1)
Where ΔV is the elimination polarization voltage value
t: Elapsed time since IG-SW7 was turned off
α, β: Coefficient

  FIG. 4 is a graph showing the relationship between the elapsed time from turning off the IG-SW 7 and the elimination polarization voltage value. Based on the plot data described above, the coefficients α and β are obtained by performing the fitting according to the equation (1). In the case of the graph shown in FIG. 4, α = 0.0481 and β = −0.3852.

Next, the processing unit 3 determines whether or not the IG-SW 7 is turned on (S8). When it is determined that the IG-SW 7 is not turned on (S8: NO), the processing unit 3 returns the process to step S8.
When it is determined that the IG-SW 7 is turned on (S8: YES), the processing unit 3 calculates the elimination polarization voltage value in the second time (S9). The elimination polarization voltage value is obtained by substituting the numerical value of the second time into t in the formula (1). As the second time, a time when the polarization is assumed to be almost completely eliminated is selected. An example of the second time is 3 days (259200 seconds) after the IG-SW 7 is turned off.

  The processing unit 3 calculates the open-circuit voltage value by subtracting the elimination polarization voltage value obtained in step S9 from the voltage value acquired when the first time has elapsed (S10), and ends the process. By step S10, the voltage value corresponding to the polarization at that time is subtracted from the voltage value acquired when the first time has elapsed, and the open-circuit voltage value when the charge polarization is almost completely eliminated is estimated.

In the present embodiment, as described above, after the IG-SW 7 is turned off, a relational expression between the elapsed time since the IG-SW 7 is turned off and the cancellation polarization voltage value is obtained using the Kalman filter, and the second time elapses. Since the elimination polarization voltage value is estimated, and the elimination polarization voltage value is subtracted from the voltage value acquired when the first time elapses to obtain the open-circuit voltage value, a current sensor and a complicated estimation equation for the polarization voltage value can be used. The open voltage value from which the voltage value corresponding to the charge polarization is removed can be accurately calculated with a simple configuration and corresponding to the state of each battery.
Therefore, when this open-circuit voltage value is used to determine the charging rate or the degree of deterioration, the accuracy is good.

In the present embodiment, the voltage value is acquired at a constant interval from the time when 3600 seconds have passed since the IG-SW 7 is turned off until the IG-SW 7 is turned on, and the relationship between the elapsed time and the cancellation polarization voltage value is obtained. Although the case of obtaining an expression is described, the present invention is not limited to this.
Moreover, based on the voltage value data acquired approximately 1 hour before the IG-SW 7 is turned on, the relationship between the elapsed time and the amount of decrease from the voltage value of the first time which is the start time of this period is plotted. The relational expression may be obtained.
As shown in FIG. 4, as the elapsed time becomes longer, the graph becomes substantially linear. Therefore, the relational expression may be approximated to a linear expression.
In the obtained relational expression, the elimination polarization voltage value when the second time has elapsed is calculated, and the elimination polarization voltage value is subtracted from the voltage value when the first time has elapsed to obtain the open-circuit voltage value.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing a schematic configuration of the power supply control device 21 including the open-circuit voltage value estimation device 22 according to Embodiment 2 of the present invention. In the figure, the same parts as those in FIG.
The power supply control device 21 includes a temperature sensor 13 that detects an external temperature, and a temperature table 33 is stored in the storage unit 31 of the processing unit 23 of the open-circuit voltage value estimation device 22.

Below, the preparation method of the temperature table 33 is demonstrated.
First, when the temperature is changed to −15 ° C., 25 ° C., and 40 ° C., the processing unit 23 performs the voltage sensor 6 at a predetermined sampling period from the lapse of a first time appropriately determined after the IG-SW 7 is turned off. The voltage value is acquired from, and the acquired voltage value is stored in the storage unit 31. Here, 3600 seconds is given as an example of the first time, and 10 seconds is given as an example of the sampling period. Then, the elimination polarization voltage value obtained by subtracting the voltage value obtained at each sampling time from the voltage value obtained when the first time has elapsed is calculated, and the obtained (elapsed time, elimination polarization voltage value) is plotted.

  The plotted graphs are shown in FIGS. FIG. 6 is a graph (semi-logarithmic graph) showing the relationship between the elapsed time of each of the batteries a, b, and c and the elimination polarization voltage value when the temperature is −15 ° C., and FIG. FIG. 8 is a graph showing the relationship between the elapsed time and the elimination polarization voltage value when the temperature is 40 ° C. The batteries a, b, and c each have a size of “60D23”, are new, and have an SOC of 100%.

By comparing FIG. 6, FIG. 7, and FIG. 8, in the case of FIG. 7 and FIG. 8, the slope of the logarithmic approximation curve is substantially constant for each battery, whereas the logarithmic approximation curve of FIG. It can be seen that the inclination of the battery varies between the range indicated by the broken line and the portion exceeding the range. Since the open-circuit voltage value at the second time after a long time has elapsed from the IG-SW 7 is estimated, the relationship between the elapsed time and the cancellation polarization voltage value is obtained in the portion exceeding the range, that is, the first point that is the starting point for obtaining this relationship. It can be seen that the time can be increased.
As described above, based on the result of obtaining the relationship between the elapsed time and the cancellation polarization voltage value for a plurality of temperatures, the processing unit 23 determines the first time corresponding to the temperature information. Is stored in the storage unit 31.

The operation of the processing unit 23 of the open-circuit voltage value estimation device 22 having the above-described configuration will be described below with reference to the flowchart of FIG.
In the present embodiment, a case where the battery is in a charged state when IG-SW 7 is turned off will be described.
First, the processing unit 23 determines whether or not the IG-SW 7 is turned off (S11). If it is determined that the IG-SW 7 is not turned off (S11: NO), the processing unit 23 returns the process to step S11.
When it is determined that the IG-SW 7 is turned off (S11: YES), the processing unit 23 causes the timer 32 to start measuring time (S12).

  Next, the processing unit 23 acquires external temperature information from the temperature sensor 13 (S13). And the process part 23 reads the said temperature table 33 from the memory | storage part 31, and determines 1st time using the temperature table 33 based on the acquired temperature information (S14). According to the temperature table 33, for example, when the temperature is −15 ° C., the first time is determined to be 12 hours, when the temperature is 10 ° C., the first time is determined to be 5 hours, and the temperature is 25 ° C. The first time is determined to be 5 hours.

  Next, the processing unit 23 determines whether or not the elapsed time after turning off the IG-SW 7 is equal to or longer than the determined first time (S15). When it is determined that the elapsed time after the IG-SW 7 is turned off is less than the first time (S15: NO), the processing unit 23 returns the process to step S15.

  When the processing unit 23 determines that the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S15: YES), the voltage sensor 6 acquires a voltage value from the first time at a predetermined sampling period. (S16) The acquired voltage value is stored in the storage unit 31 (S17). An example of the sampling period is 10 seconds.

The processing unit 23 calculates a cancellation polarization voltage value obtained by subtracting the acquired voltage value from the voltage value acquired when the first time has elapsed (S18).
The processing unit 23 plots the obtained (elapsed time, elimination polarization voltage value), uses the Kalman filter (for example, the least squares method) to obtain the coefficients (α, β) by fitting according to the above equation (1), and the relationship The formula is established (S19).

Next, the processing unit 23 determines whether or not the IG-SW 7 is turned on (S20). If it is determined that the IG-SW 7 is not turned on (S20: NO), the processing unit 3 returns the process to step S20.
When it determines with IG-SW7 having been turned ON (S20: YES), the process part 23 calculates the cancellation | release polarization voltage value in 2nd time (S21). The elimination polarization voltage value is obtained by substituting the numerical value of the second time into t in the formula (1). An example of the second time is 3 days (259200 seconds) after the IG-SW 7 is turned off.

  The processing unit 23 calculates the open-circuit voltage value by subtracting the elimination polarization voltage value obtained in step S21 from the voltage value acquired when the first time has elapsed (S22), and ends the process. By step S22, the voltage value for the polarization at that time is subtracted from the voltage value acquired when the first time has elapsed, and the open-circuit voltage value when the charge polarization is almost completely eliminated is estimated.

  In the present embodiment, since the first time is determined according to the temperature, the above relational expression can be approximated better when the open-circuit voltage value at the second time is estimated. Therefore, the open-circuit voltage value can be calculated with higher accuracy, and when the charge rate or the degree of deterioration is obtained using this open-circuit voltage value, the accuracy becomes better.

Embodiment 3 FIG.
The power supply control device 21 according to the third embodiment of the present invention is the power supply control according to the second embodiment except that the temperature table 33 is not stored in the storage unit 31 of the processing unit 23 of the open-circuit voltage value estimation device 22. It has the same configuration as the device 21. The processing by the processing unit 23 is different from the processing according to the second embodiment.

The operation of the processing unit 23 of the open-circuit voltage value estimation device 22 having the above-described configuration will be described below with reference to the flowchart of FIG.
In the present embodiment, a case where the battery is in a charged state when IG-SW 7 is turned off will be described.
First, the processing unit 23 determines whether or not the IG-SW 7 is turned off (S31). When it is determined that the IG-SW 7 is not turned off (S31: NO), the processing unit 23 returns the process to step S31.
When it is determined that the IG-SW 7 is turned off (S31: YES), the processing unit 23 causes the timer 32 to start measuring time (S32).

Next, the processing unit 23 acquires external temperature information from the temperature sensor 13 (S33).
And the process part 23 determines whether temperature is 10 degrees C or less (S34). Processing unit 23, when the temperature is determined to be 10 ° C. or less (S34: YES), determines the first hour t ₁ hour (S35). Processor 23 temperature is not 10 ° C. or less, i.e., when the temperature is determined to exceed 10 ℃ (S34: NO), determines the first hour t ₂ h (S36). Here, an example of t ₁ time is 5 hours, and an example of t ₂ time is 1 hour. Moreover, the threshold value of the temperature determined in step S34 is not limited to 10 ° C. Similar to the second embodiment, the temperature threshold value, the t ₁ time value, and the t ₂ time value are set based on the result of obtaining the relationship between the elapsed time and the elimination polarization voltage value for a plurality of temperatures.

  Next, the processing unit 23 determines whether or not the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S37). When it is determined that the elapsed time after the IG-SW 7 is turned off is less than the first time (S37: NO), the processing unit 23 returns the process to step S37.

  When the processing unit 23 determines that the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S37: YES), the voltage sensor 6 acquires a voltage value from the first time at a predetermined sampling period. (S38) The acquired voltage value is stored in the storage unit 31 (S39). An example of the sampling period is 10 seconds.

The processing unit 23 calculates a cancellation polarization voltage value obtained by subtracting the acquired voltage value from the voltage value acquired when the first time has elapsed (S40).
The processing unit 23 plots the obtained (elapsed time, elimination polarization voltage value), uses the Kalman filter (for example, the least squares method) to obtain the coefficients (α, β) by fitting according to the above equation (1), and the relationship Formula is established (S41).

Next, the processing unit 23 determines whether or not the IG-SW 7 is turned on (S42). When it is determined that the IG-SW 7 is not turned on (S42: NO), the processing unit 3 returns the process to step S42.
When it determines with IG-SW7 having been turned on (S42: YES), the process part 23 calculates the cancellation | release polarization voltage value in 2nd time (S43). The elimination polarization voltage value is obtained by substituting the numerical value of the second time into t in the formula (1). An example of the second time is 3 days (259200 seconds) after the IG-SW 7 is turned off.

  The processing unit 23 calculates the open-circuit voltage value by subtracting the elimination polarization voltage value obtained in step S9 from the voltage value acquired when the first time has elapsed (S44), and ends the process.

  In the present embodiment, since the first time is determined according to the temperature, the above relational expression can be approximated better when the open-circuit voltage value at the second time is estimated. Therefore, the open-circuit voltage value can be calculated with higher accuracy, and when the charge rate or the degree of deterioration is obtained using this open-circuit voltage value, the accuracy becomes better.

Embodiment 4 FIG.
The power supply control device according to the fourth embodiment of the present invention has the same configuration as the power supply control device 1 including the open-circuit voltage value estimation device 2 according to the first embodiment, and the processing by the processing unit 3 is performed in the first embodiment. This is different from the processing related to.

The operation of the processing unit 3 of the open-circuit voltage value estimation device 2 having the above-described configuration will be described below with reference to the flowchart of FIG.
In the present embodiment, a case where the IG-SW 7 is in a discharged state when the IG-SW 7 is turned off (a case where the acquired voltage value increases with time) will be described.
First, the processing unit 3 determines whether or not the IG-SW 7 is turned off (S51). When it is determined that the IG-SW 7 is not turned off (S51: NO), the processing unit 3 returns the process to step S51. .
When it is determined that the IG-SW 7 is turned off (S51: YES), the processing unit 3 causes the timer 32 to start measuring time (S52).

Next, the processing unit 3 determines whether or not the elapsed time from the turn-off of the IG-SW 7 is equal to or longer than the first time (S53). As the first time, a time longer than the time during which the voltage value corresponding to the discharge polarization rapidly increases is set. An example of the first time is 1500 seconds.
When it is determined that the elapsed time after the IG-SW 7 is turned off is less than the first time (S53: NO), the processing unit 3 returns the process to step S53.

  When the processing unit 3 determines that the elapsed time after the IG-SW 7 is turned off is equal to or longer than the first time (S53: YES), the voltage sensor 6 acquires a voltage value from the first time at a predetermined sampling period. (S54), the acquired voltage value is stored in the storage unit 31 (S55). An example of the sampling period is 10 seconds.

FIG. 12 is a graph showing the relationship between the elapsed time from the turn-off of the IG-SW 7 and the voltage value.
In FIG. 12, it can be seen that when the elapsed time exceeds 1500 seconds, the degree of change in the voltage value is moderate.

The processing unit 3 calculates a resolved polarization voltage value (a resolved polarization voltage value) obtained by subtracting the acquired voltage value from the acquired voltage value when the first time has elapsed (S56).
The processing unit 3 plots the obtained (elapsed time, elimination polarization voltage value), obtains coefficients (γ, δ) by fitting according to the following equation (2) using a Kalman filter, and establishes a relational expression ( S57).
ΔV = γ × ln (t) + δ (2)

  FIG. 13 is a graph showing the relationship between the elapsed time from the turn-off of the IG-SW 7 and the elimination polarization voltage value. Based on the plot data described above, the coefficients γ and δ are obtained by performing the fitting according to the equation (2). In the case of the graph shown in FIG. 13, γ = 0.0384 and δ = −0.2801.

Next, the processing unit 3 determines whether or not the IG-SW 7 is turned on (S58). When it is determined that the IG-SW 7 is not turned on (S58: NO), the processing unit 3 returns the process to step S58.
When it is determined that the IG-SW 7 is turned on (S58: YES), the processing unit 3 calculates the elimination polarization voltage value in the second time (S59). The elimination polarization voltage value is obtained by substituting the numerical value of the second time into t in the equation (2). As the second time, a time when the polarization is assumed to be almost completely eliminated is selected. An example of the second time is 4500 seconds after the IG-SW 7 is turned off.

  The processing unit 3 calculates the open-circuit voltage value by adding the elimination polarization voltage value obtained in step S59 to the voltage value acquired when the first time has elapsed (S60), and ends the process. By step S60, the voltage value corresponding to the polarization at that time is added to the voltage value acquired when the first time has elapsed, and the open-circuit voltage value when the discharge polarization is almost completely eliminated is estimated.

In the present embodiment, as described above, after the IG-SW 7 is turned off, a relational expression between the elapsed time since the IG-SW 7 is turned off and the canceled polarization voltage value at the time of discharge is obtained using the Kalman filter, and the second time Estimating the elimination polarization voltage value at the time of elapse, and adding the estimated elimination polarization voltage value to the voltage value acquired at the time of the first time to obtain the open-circuit voltage value, so that the current sensor and a complex polarization voltage value estimation formula The open-circuit voltage value from which the voltage value corresponding to the charge polarization is removed can be accurately calculated with a simple configuration and corresponding to the state of each battery.
Therefore, when this open-circuit voltage value is used to determine the charging rate or the degree of deterioration, the accuracy is good.

In the present embodiment, the voltage value is acquired at regular intervals from the time when 1500 seconds as the first time has elapsed since the IG-SW 7 is turned off until the IG-SW 7 is turned on, and the elapsed time is eliminated. Although the case of obtaining the relational expression with the polarization voltage value has been described, the present invention is not limited to this. Further, as in the second and third embodiments, external temperature information may be acquired and the first time may be determined based on the acquired temperature information.
Based on the voltage value data acquired approximately 1 hour before the IG-SW 7 is turned on, the relationship between the elapsed time and the amount of increase from the voltage value of the first time which is the start time of this period is plotted. An expression may be obtained.
As shown in FIG. 13, as the elapsed time becomes longer, the graph becomes substantially linear. Therefore, the relational expression may be approximated to a linear expression.
In the obtained relational expression, the elimination polarization voltage value when the second time has elapsed is calculated, and the elimination polarization voltage value is added to the voltage value when the first time has elapsed to obtain the open circuit voltage value.

In the first to fourth embodiments, the case where the coefficient of the relational expression is calculated by the Kalman filter (least square method) is described, but the present invention is not limited to this. However, it is preferable to calculate the coefficient of the relational expression using the Kalman filter because the fitting accuracy is good and the elimination polarization voltage value when the second time elapses can be accurately estimated.
Further, the first time, the second time, and the sampling period are not limited to the numerical values described in the first to fourth embodiments.

It is a block diagram which shows schematic structure of a power supply control apparatus provided with the open circuit voltage value estimation apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process of the process part of the open circuit voltage value estimation apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between the elapsed time from OFF of IG-SW, and a voltage value. It is a graph which shows the relationship between the elapsed time from OFF of IG-SW, and a cancellation | release polarization voltage value. It is a block diagram which shows schematic structure of a power supply control apparatus provided with the open circuit voltage value estimation apparatus which concerns on Embodiment 2 of this invention. It is a graph which shows the relationship between each elapsed time and cancellation | release polarization voltage value of battery a, b when temperature is -15 degreeC. It is a graph which shows the relationship between the elapsed time in case temperature is 25 degreeC, and a cancellation | release polarization voltage value. It is a graph which shows the relationship between the elapsed time in case temperature is 40 degreeC, and a cancellation | release polarization voltage value. It is a flowchart which shows the process of the process part of the open circuit voltage value estimation apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the process of the process part of the open circuit voltage value estimation apparatus which concerns on Embodiment 3 of this invention. It is a flowchart which shows the process of the process part of the open circuit voltage value estimation apparatus which concerns on Embodiment 4 of this invention. It is a graph which shows the relationship between the elapsed time from OFF of IG-SW, and a voltage value. It is a graph which shows the relationship between the elapsed time from OFF of IG-SW, and a cancellation | release polarization voltage value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 21 Power supply control apparatus 2, 22 Opening voltage value estimation apparatus 3, 23 Processing part 31 Storage part 32 Timer 33 Temperature table 4 Output part 5 Battery 6 Voltage sensor 7 IG-SW
8 Ignition device 9 Engine 10 Alternator 11 Load 13 Temperature sensor

Claims (7)

An open-circuit voltage value estimation method for estimating an open-circuit voltage value of a battery charged by an in-vehicle generator that generates power in conjunction with an engine,
Determine if the engine has stopped,
If it is determined that the engine has stopped, the voltage value of the battery at three or more subsequent time points including an appropriate first time point after the engine stop is acquired and stored;
Obtaining a difference value between the voltage value acquired at the first time point and the voltage value acquired after the first time point has passed;
Find the relationship between the time elapsed since the engine stopped and the calculated difference value,
Determine if the engine has started,
When it is determined that the engine has started, the estimated difference value at the second time point after the engine start is obtained using the relational expression,
An open-circuit voltage value estimation method, wherein an open-circuit voltage value is obtained based on the voltage value acquired at the first time point and the estimated difference value.   2. The open circuit according to claim 1, wherein after the engine is stopped, the open voltage value is obtained by subtracting the estimated difference value from the voltage value acquired at the first time point when the acquired voltage value has decreased with time. Voltage value estimation method.   2. The open circuit according to claim 1, wherein after the engine is stopped, when the acquired voltage value increases with time, the open voltage value is obtained by adding the estimated difference value to the voltage value acquired at the first time point. Voltage value estimation method. Get temperature information,
The open circuit voltage value estimation method according to any one of claims 1 to 3, wherein the first time point is determined based on the acquired temperature information. In advance,
For a plurality of temperatures, acquire and store voltage values of the battery at three or more time points thereafter including an appropriate first time point after engine stop,
Obtaining a difference value between the voltage value acquired at the first time point and the voltage value acquired after the first time point has passed;
Find the relationship between the time elapsed since the engine stopped and the calculated difference value,
Create a table for determining the first time point based on the temperature information from the relationship for a plurality of temperatures,
The open circuit voltage value estimation method according to claim 4, wherein the first time point is determined using the table based on the acquired temperature information. An open-circuit voltage value estimation device that estimates an open-circuit voltage value of a battery charged by an on-vehicle generator that generates power in conjunction with an engine,
First determination means for determining whether or not the engine has stopped;
Means for measuring an elapsed time after the engine is stopped when it is determined by the first determination means that the engine has stopped;
Second determination means for determining whether or not the elapsed time is equal to or longer than the first time;
Means for obtaining a voltage value of the battery at three or more time points including the first time when the second determination means determines that the elapsed time is equal to or longer than the first time;
Storage means for storing the acquired voltage value;
Means for obtaining a difference value between the voltage value acquired when the first time elapses and the voltage value acquired after the first time elapses;
Means for obtaining a relational expression between the elapsed time from the engine stop and the obtained difference value;
Third determination means for determining whether or not the engine has started;
Means for obtaining an estimated difference value at the elapse of a second time after the engine start using the relational expression when the third determination means determines that the engine has started;
An open-circuit voltage value estimation device comprising: means for determining an open-circuit voltage value based on the voltage value acquired when the first time has elapsed and the estimated difference value. Means for detecting the temperature;
The open-circuit voltage value estimation apparatus according to claim 6, further comprising: means for determining the first time based on the temperature detected by the means.

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