JP5203496B2 - Battery state detection method, battery state detection device, and battery power supply system - Google Patents

Description

The present invention relates to a battery state detection method, a battery state detection device to which the battery state detection method is applied, and a battery power supply system equipped with the battery state detection device.

In recent years, many electric devices have been mounted in the automobile field, and in particular, the importance of the on-vehicle power source has been further increased with the progress of electric control of safety devices. In addition, in order to respond to energy saving and carbon dioxide emission regulations, it is required to secure an idling stop function and its restart capability at intersections and the like.

With the widespread use of idle stops, a technique for accurately monitoring the state of the battery has been strongly desired in order to ensure the restart capability. Thus, as the importance of the battery increases, the need for a technique for monitoring the state of the battery and detecting the state is rapidly increasing, and accordingly, the degree of deterioration (SOH) or the discharge capacity of the battery is increased. Many techniques for predicting (SOF) have been proposed (Patent Documents 1 to 4).

In Patent Document 1, as a battery state monitoring method, a technique for obtaining an approximate expression indicating a correlation between an internal resistance and a remaining capacity before a certain period in the vicinity of the end of the battery life, and sequentially updating the battery life prediction based thereon. Is disclosed. Further, in Patent Document 2, the battery discharge amount is obtained from the voltage drop calculated from the measured voltage and the internal resistance value obtained from the table stored in advance, and this is subtracted from the previously calculated electricity amount to obtain the current electricity. A discharge monitoring device for determining and monitoring the quantity is disclosed.

Patent Document 3 discloses a method of estimating the remaining battery capacity reflecting the characteristics of the open circuit voltage and internal resistance at the time of engine start. Further, it is described that whether or not the engine can be started is determined using the estimated remaining capacity. Further, Patent Document 4 discloses a monitoring device that calculates the charging rate of a battery from voltage / current, calculates the amount of electricity in use, and calculates the time until the battery runs out.

Patent No. 4011303 No. 7-42151 JP 2004-42799 A JP 2007-253716 A

If you continue to discharge without charging the battery, such as when idling is stopped, if you continue to discharge without considering the state of the battery, when you try to start the engine again, the remaining capacity of the battery will run short and restart There is a risk that it may become impossible or an important device such as a control device may become inoperable.

Although the techniques disclosed in the above-mentioned patent documents 1 to 4 describe a technique for estimating or calculating the remaining capacity of the battery, the engine start and the like without affecting important equipment such as a control device. There is no description of a technique for securing a charging capacity necessary for device operation. Even when the charge capacity is maintained to some extent, depending on the deterioration state of the battery, etc., there is a risk that the voltage may be significantly reduced by starting the engine or the like, thereby causing a problem that the control device cannot operate normally.

The present invention has been made to solve these problems, with respect to the battery being discharged, the battery state detection that Do is possible to ensure the charge capacity required to operate the predetermined device It is an object to provide a method, a battery state detection device, and a battery power supply system.

A first aspect of the battery state detection method of the present invention is a state detection method for a vehicle battery that supplies power to a load while the engine is stopped, and uses a current value and internal resistance or internal impedance as variables. Create a voltage drop amount calculation formula to calculate the amount of voltage drop from the stable voltage due to discharge in advance, measure the battery current value and internal resistance or internal impedance, and calculate the battery charge rate from the current value Then, the stable voltage is estimated, and the voltage drop amount is calculated by substituting the current value for device operation, which is the current value when starting the engine, and the internal resistance or the internal impedance into the voltage drop amount calculation formula. The response voltage at the time of starting the engine is calculated by subtracting the voltage drop amount from the stable voltage, and when it is determined that the response voltage is equal to or less than a predetermined threshold, a predetermined negative Actuating control, the battery state detection process, the charge rate as variables, and the calculated correlation equation of the internal resistance or the internal impedance created beforehand with an adjustment parameter, measured value and the interior of the internal resistance or the internal impedance The adjustment parameter is determined by substituting the charging rate at the time of measuring resistance or internal impedance into the calculated correlation equation, and the internal resistance or internal impedance is determined by substituting the charging rate and the determined adjustment parameter into the calculated correlation equation. And calculating the voltage drop amount, substituting the internal resistance or internal impedance into the voltage drop amount calculation formula .

Another aspect of the battery state detection method of the present invention is a state detection method for a vehicle battery that supplies power to a load while the engine is stopped, and discharges the current value and internal resistance or internal impedance as variables. Create a voltage drop amount calculation formula to calculate the amount of voltage drop from the stable voltage by measuring in advance, measure the current value and internal resistance or internal impedance of the battery, and calculate the charge rate of the battery from the current value The stable voltage is estimated, and the current value for device operation, which is the current value when the engine is started, and the internal resistance or the internal impedance are substituted into the voltage drop amount calculation formula to calculate the voltage drop amount, A response voltage at the time of starting the engine is calculated by subtracting the voltage drop amount from the stable voltage, and a predetermined load is determined when it is determined that the response voltage is equal to or less than a predetermined threshold value. Actuating the control, in the battery state detection process, the current value as a variable, and the calculated correlation equation of the internal resistance or the internal impedance created beforehand with an adjustment parameter, measured value and the interior of the internal resistance or the internal impedance The adjustment parameter is determined by substituting the discharge current value at the time of measuring resistance or internal impedance into the calculated correlation equation, and the device operation current value and the determined adjustment parameter are substituted into the calculated correlation equation Resistance or internal impedance is calculated, and in calculating the voltage drop, the internal resistance or internal impedance is substituted into the voltage drop calculation formula.

Another aspect of the battery state detection method of the present invention is a state detection method for a vehicle battery that supplies power to a load while the engine is stopped, and discharges the current value and internal resistance or internal impedance as variables. Create a voltage drop amount calculation formula to calculate the amount of voltage drop from the stable voltage by measuring in advance, measure the current value and internal resistance or internal impedance of the battery, and calculate the charge rate of the battery from the current value The stable voltage is estimated, and the current value for device operation, which is the current value when the engine is started, and the internal resistance or the internal impedance are substituted into the voltage drop amount calculation formula to calculate the voltage drop amount, A response voltage at the time of starting the engine is calculated by subtracting the voltage drop amount from the stable voltage, and a predetermined load is determined when it is determined that the response voltage is equal to or less than a predetermined threshold value. Actuating the control, in the battery state detection process, the temperature as a variable, and the calculated correlation equation of the internal resistance or the internal impedance with adjustable parameters created in advance, the measurement value and the internal resistance of the internal resistance or the internal impedance Alternatively, the adjustment parameter is determined by substituting the temperature at the time of internal impedance measurement into the calculated correlation equation, and the internal resistance or the internal impedance is determined by substituting the battery temperature and the determined adjustment parameter into the calculated correlation equation. In the calculation of the voltage drop amount, the internal resistance or the internal impedance is substituted into the voltage drop amount calculation formula.

Another aspect of the battery state detection method according to the present invention is characterized in that the load control is control for stopping a device having a low priority.

Another aspect of the battery state detection method of the present invention is a state detection method for a vehicle battery that supplies power to a load while the engine is stopped, and discharges the current value and internal resistance or internal impedance as variables. Create a voltage drop amount calculation formula to calculate the amount of voltage drop from the stable voltage by measuring in advance, measure the current value and internal resistance or internal impedance of the battery, and calculate the charge rate of the battery from the current value The stable voltage is estimated, and the current value for device operation, which is the current value when the engine is started, and the internal resistance or the internal impedance are substituted into the voltage drop amount calculation formula to calculate the voltage drop amount, A response voltage at the time of starting the engine is calculated by subtracting the voltage drop amount from the stable voltage, and a predetermined load is determined when it is determined that the response voltage is equal to or less than a predetermined threshold value. Actuating the control, in the battery state detection process, the load control is characterized by by starting the engine is controlled to start the charging of the battery.

The battery state detection device of the present invention includes a battery state measurement unit that measures at least internal resistance or internal impedance of a battery, a storage unit that stores a current value for device operation that is a current value when the engine is started, Input the current value and internal resistance or internal impedance of the battery from the battery state measurement unit, calculate the charging rate of the battery from the current value, estimate the stable voltage, and read the device operation from the storage unit Substituting the current value and the internal resistance or internal impedance into a voltage drop amount calculation formula created in advance to calculate the voltage drop amount, subtracting the voltage drop amount from the stable voltage, and the response at the time of starting the engine calculating a voltage, and a processing unit for actuating a predetermined load control when the response voltage is determined to be equal to or less than a predetermined threshold value, prior to Arithmetic control unit is characterized in that to start charging of said start the engine as the load control to the battery.

The battery power supply system of this invention is provided with the said battery state detection apparatus and a battery, It is characterized by the above-mentioned .

According to the present invention, with respect to the battery during discharge, to provide a battery state detection process, the battery state detection device and a battery power supply system that a Do and the charge capacity can be secured required to operate the predetermined device be able to.

It is a flowchart showing a process flow of the discharge duration prediction method for battery-. It is a figure which shows an example of the change of the battery voltage by discharge. It is a diagram illustrating an example of a change of a stable voltage and response voltage for explaining the discharge duration prediction method for battery-. It is a figure which shows the correlation with a stable voltage and charging capacity. It is a flowchart which shows the flow of a process of another discharge duration prediction method. It is a figure which shows an example of the correlation of internal impedance and charging capacity. It is a figure which shows an example of the electric current and response voltage which are required for engine starting. It is a flowchart which shows the flow of a process of the battery state detection method in embodiment of this invention. It is a block diagram which shows schematic structure of the battery state detection apparatus and battery power supply system in embodiment of this invention.

A configuration of a battery discharge duration prediction method, a battery state detection method, a battery state detection device, and a battery power supply system according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

When discharging from the battery is continued with a predetermined discharge current pattern, the battery voltage decreases, for example, as the voltage 10 shown in FIG. 2 as the charge capacity decreases. For devices that receive power from the battery, the minimum voltage (threshold, hereinafter referred to as the operation limit voltage Vth) required for its operation is specified, and when the battery continues to discharge and the battery voltage reaches the operation limit voltage or less. After that, the device will not work properly.

Further, even when the battery voltage is ensured to be equal to or higher than the operation limit voltage, there is a possibility that the device that has been stopped until then cannot be operated. For example, in FIG. 2, when the battery voltage 10 is accompanied by a voltage drop having a magnitude indicated by reference numeral 11 when the stopped device is operated, the voltage at the time of the voltage drop needs to be equal to or higher than the operation limit voltage. .

Here, with the discharge duration prediction method of the battery will be described below with reference to the drawings. Here , the voltage when the predetermined device (hereinafter referred to as device B) is operated while discharging from the battery in a predetermined current pattern (hereinafter referred to as current pattern A) reaches the operation limit voltage Vth. Predict the duration of discharge until then . The method for predicting discharge electrostatic duration, will be described with reference to FIG.

The discharge duration prediction method battery-predicts a change in the stable voltage with decreasing charge capacity due to the discharge current pattern A. The stable voltage corresponds to an open circuit voltage (OCV) when the battery is stable without charging / discharging for a long time. In FIG. 3, an example of a change in the stable voltage predicted in the present embodiment (hereinafter simply expressed as OCV) is indicated by reference numeral 21. Further, a voltage drop ΔV when the device B is operated is indicated by reference numeral 22, and a response voltage after the voltage drop is indicated by 23. Here , the voltage drop 22 when the device B is operated and the response voltage 23 after the voltage drop are predicted. Then, the discharge duration until the predicted response voltage 23 reaches the operation limit voltage Vth is obtained.

The discharge duration prediction method battery-will be described in detail with reference to the flowchart shown in FIG.
Here , the voltage drop calculation formula is used to calculate the voltage drop ΔV from the stable voltage due to the discharge when the device B is operated, and the voltage drop calculation formula is created in advance in the first step S1. doing. In the first step S1, a current pattern for continuously discharging from the battery is also created in advance. In this discharge duration prediction method, the discharge duration is obtained while advancing the elapsed time t from a predetermined time point by a predetermined time width Δt, and zero is set to the elapsed time t in the first step S1 as an initial value of the elapsed time t. Is set.

ここで、α、βは実験データ等をもとに事前に決定される定数である。第１ステップＳ１で作成される電圧降下量算出式として、上式を用いることができる。 The voltage drop amount ΔV has the following correlation between the discharge current value I and the internal resistance or internal impedance of the battery (in the following, the internal impedance Z will be described as an example).

Here, α and β are constants determined in advance based on experimental data or the like. As the voltage drop amount calculation formula created in the first step S1, the above formula can be used.

In the second step S2, the internal resistance or internal impedance of the battery at a predetermined time is measured.
The subsequent third step S3 and subsequent steps are repeatedly executed until the discharge duration is determined. First, in the third step S3, the elapsed time t is advanced by the time width Δt.

In 4th step S4, the charging rate in the time of the elapsed time t is calculated as charging rate calculation. This is for use in the stable voltage prediction calculation of the next step. When the full charge capacity of the battery is Cnom, the charging rate SOC can be calculated by the following equation.

ここで、上式の積分は、経過時間ｔの期間の電流Ｉを合計することを示している。 In (Expression 2), the charge capacity decrease amount ΔC is a time integral of the discharge current I when the discharge is continued with the current pattern A for the elapsed time t from a predetermined time point, and can be calculated by the following expression.

Here, the integration of the above equation indicates that the current I during the elapsed time t is summed.

ここで、パラメータＫ１、Ｋ２は実験等で事前に決定されるパラメータである。 In the fifth step S5, as a stable voltage prediction calculation, a stable voltage is predicted when the discharge is continued with the current pattern A from a predetermined time and the elapsed time t has elapsed. There is a correlation as shown in FIG. 4 between the stable voltage OCV and the charging rate SOC. Accordingly, the stable voltage OCV can be calculated by the following equation using the charging rate SOC calculated in the fourth step S4.

Here, the parameters K1 and K2 are parameters determined in advance by an experiment or the like.

In the sixth step S6, as the voltage drop amount calculation, the voltage drop amount ΔV from the stable voltage OCV is calculated using the voltage drop amount calculation formula created in the first step S1. Substituting the device operating current value I when the device B is operated and the internal impedance Z measured in the second step S2 into the voltage drop calculation formula shown in (Equation 1), the voltage drop ΔV is calculated. calculate.

In the seventh step S7, as the response voltage prediction calculation, the device B at the time of the elapsed time t is subtracted from the stable voltage OCV predicted in the fifth step S5 by subtracting the voltage drop amount ΔV calculated in the sixth step S6. The response voltage V when the is operated is calculated.

In the eighth step S8, the response voltage V predicted in the seventh step S7 is compared with the operation limit voltage Vth. Returns to the third step S3, advances the elapsed time t by Δt, and repeats the calculation after the fourth step. Further, when the response voltage V is sufficiently close to the operation limit voltage Vth (the difference between the two is a minute value ε or less), it is determined that the response voltage V has reached the operation limit voltage Vth, and in the next ninth step S9, The elapsed time t is set as the discharge duration.

In the battery discharge duration prediction method described above, the voltage drop amount ΔV is calculated using (Equation 1). As the internal impedance used for this calculation, the value measured in the second step S2 above is used. Is used. However, since the internal impedance changes depending on the charging capacity, current, temperature, etc. of the battery, it is possible to further improve the accuracy of the discharge duration by correcting this and using the value in a predetermined reference state. It becomes. The flow of processing which is adapted to correct the internal impedance shown in FIG.

ここでＣは調整パラメータであり、ｆ_１(Ｃ)、ｇ_１(Ｃ)は予め実験等で定めた調整パラメータＣを変数とする関数である。 As an example, there is a correlation between the internal impedance and the charging rate SOC as shown in FIG. Therefore, the internal impedance used for calculating the voltage drop amount ΔV can be corrected by the charge capacity SOC at the elapsed time t. As an example, the internal impedance Z can be expressed as a function of the charge capacity SOC as in the following equation.

Here, C is an adjustment parameter, and f ₁ (C) and g ₁ (C) are functions having the adjustment parameter C determined in advance by experiments as a variable.

The calculation formula of the internal impedance Z in (Expression 6) needs to satisfy the internal impedance measured in the second step S2 and the charge capacity SOC at that time. Therefore, the adjustment parameter C can be determined by substituting the measured value of the internal impedance and the charge capacity SOC at that time into (Equation 6). The adjustment parameter C can be determined in the second step S2.

In the processing flow shown in FIG. 5, step S11 is added after the fourth step S4, and the internal impedance is corrected here. That is, using the adjustment parameter C determined in the second step S2, the internal impedance is calculated by substituting the charging rate SOC calculated in the fourth step S4 together with the adjustment parameter C into (Equation 6).

ここで、Ｄは調整パラメータであり、ｆ_２(Ｄ)、ｇ_２(Ｄ)は予め実験等で定めた調整パラメータＤを変数とする関数である。 As another method of correcting the internal impedance, there is a method of correcting with the current value flowing through the battery. There is a correlation between the internal impedance and the current value I as shown by the following equation, for example.

Here, D is an adjustment parameter, and f ₂ (D) and g ₂ (D) are functions having the adjustment parameter D defined in advance through experiments or the like as a variable.

The formula for calculating the internal impedance Z in (Expression 7) needs to satisfy the internal impedance measured in the second step S2 and the current value I at that time. Therefore, the adjustment parameter D can be determined by substituting the measured value of the internal impedance and the current value I at that time into (Equation 7). The determination of D can be made in the second step S2.

Further, the internal impedance correction calculation is performed by substituting the current value for device operation when the device B is operated in step S11 into the current value I of (Equation 7) together with the adjustment parameter D, thereby calculating the corrected internal impedance. Can be calculated. When the device operating current value is constant regardless of the elapsed time t, the internal impedance correction calculation is performed simultaneously with the determination of the adjustment parameter D in the second step S2, for example. May be.

ここで、Ｅは調整パラメータであり、ｆ_３（Ｅ）、ｇ_３（Ｅ）、ｌ_３（Ｅ）は予め実験等で定めたパラメータＥの関数である。 As another method of correcting the internal impedance, there is a method of correcting by the battery temperature. There is a correlation between the internal impedance and the battery temperature (referred to as Temp) as shown in the following equation, for example.

Here, E is an adjustment parameter, and f ₃ (E), g ₃ (E), and l ₃ (E) are functions of the parameter E determined in advance through experiments or the like.

The formula for calculating the internal impedance Z in (Equation 8) needs to satisfy the internal impedance measured in the second step S2 and the battery temperature Temp at that time. Therefore, the fitting parameter E can be determined from the measured value of the internal impedance and the battery temperature Temp at that time. In the second step S2, the battery temperature Temp is measured simultaneously with the measurement of the internal impedance, and the fitting parameter E can be determined using this.

Further, the internal impedance correction calculation according to (Equation 8) may be performed in step S11. However, when the value measured in the second step S2 is used as the battery voltage Temp, the internal impedance correction calculation is performed in the second step. It may be performed after the fitting parameter E is determined in S2.

ここで、ｇ１（ＳＯＣ）、ｇ２（ＳＯＣ）、ｇ３（ＳＯＣ）、ｇ４（ＳＯＣ）は、ＳＯＣの関数となっており、さらにそれらの各係数は予め定めた調整パラメータの関数として表現される。
また、上記では温度Ｔｅｍｐと充電率ＳＯＣに関して補正する相関式の例を述べたが、温度Ｔｅｍｐと電流Ｉ、或いは充電率ＳＯＣと電流Ｉ、さらには温度Ｔｅｍｐと電流Ｉと充電率ＳＯＣの全てについても同様に補正相関式を策定し、適宜補正計算を行なうことができる。） As a correlation formula for correcting the internal impedance, a formula other than (Formula 6) to (Formula 8) may be used. For example, the internal impedance may be corrected using a correlation equation including two or more of the charging rate SOC, the current value I, and the battery temperature Temp. As an example, the accuracy of the internal impedance can be further improved by using the following correlation equation including the charge capacity SOC and the battery temperature Temp.

Here, g1 (SOC), g2 (SOC), g3 (SOC), and g4 (SOC) are functions of SOC, and each coefficient thereof is expressed as a function of a predetermined adjustment parameter.
In the above description, the correlation equation for correcting the temperature Temp and the charging rate SOC has been described. However, the temperature Temp and the current I, or the charging rate SOC and the current I, and further all of the temperature Temp, the current I, and the charging rate SOC. Similarly, it is possible to formulate a correction correlation equation and perform correction calculation as appropriate. )

また、（式６）〜（式９）に示した内部インピーダンスの補正式は、内部抵抗に対しても同様に作成することができる。 In the above description, the internal impedance of the battery has been described as an example, but even when the internal resistance of the battery is used, the discharge duration can be obtained by the same processing. When the internal resistance R of the battery is used, the following equation may be used instead of the above (Equation 1).

The internal impedance correction formulas shown in (Formula 6) to (Formula 9) can be similarly created for the internal resistance.

The predicted discharge duration as described above can be used for battery state monitoring, load control, and the like. As an example of load control using the discharge duration determined as described above, if the discharge duration is determined to be shorter than a predetermined threshold (load control time), the priority of the current pattern A It is possible to control so as to reduce the amount of supply current by stopping low devices and to enable power supply for a longer time. Alternatively, as another example of the load control, when it is determined that the discharge duration is shorter than the load control time, the battery can be controlled to start charging.

The above-described battery discharge duration prediction method can be applied to predicting an allowable idling stop period in advance when performing idling stop in a vehicle, for example. When the vehicle stops the engine due to idling stop, the in-vehicle electrical components that have been used so far continue to operate even after the engine is stopped, and thus current is continuously supplied from the battery to such in-vehicle electrical components. If the engine is stopped for a long time and the amount of discharge from the battery during that time increases, there is a possibility that the engine cannot be restarted even if the engine is subsequently restarted.

When starting the engine, a large current is required in a short time, as illustrated in FIG. Therefore, the response voltage due to the discharge at the start of the engine generates a large voltage drop (indicated by ΔV in the figure) as illustrated in FIG.7 (b). If it is greatly reduced due to the discharge until then, the response voltage may fall below a threshold value (indicated by Vth in the figure) due to a voltage drop at the start of the engine. This is equivalent to the minimum voltage required for normal operation of the product, and if the response voltage falls below this level, there is a risk that in-vehicle electrical components may not operate normally, especially for control devices such as important equipment. If you can't, you will have a big hindrance to driving.

Therefore, by using the above-described battery discharge duration prediction method, it is possible to know in advance the maximum idling stop time during which the engine can be started. That is, in the battery discharge duration prediction method described above , the current pattern A is set as a discharge current pattern during idling, the device B is used as an engine, the voltage drop ΔV and the response voltage at the start are predicted, and the engine is based on this. It is possible to predict an idling stop period that can be started.

Next, a battery state detection method, a battery state detection device, and a battery power supply system according to an embodiment of the present invention will be described below. The battery state detection method, the battery state detection device, and the battery power supply system of the present invention apply the above-described battery discharge duration prediction method to battery monitoring / control. The battery monitoring / control by the battery state detection method or the like of the present embodiment is particularly suitable for application to battery monitoring and load control when the vehicle is idling stopped.

The battery state detection method of the present embodiment will be described with reference to the flowchart shown in FIG. When load control is performed by monitoring the battery state, it is not necessary to repeat the calculation while advancing the elapsed time as in the case of predicting the discharge duration. In the following, the battery state detection method of the present embodiment will be described by taking idling stop as an example, but the present invention is not limited to this.

In the first step S21 of the battery state detection method of the present embodiment, a voltage drop amount calculation formula is created in advance. As this voltage drop amount calculation formula, the one used in the discharge duration prediction can be used as it is, and for example, (Formula 1) or (Formula 10) can be used. In the second step S22, the current internal resistance or internal impedance of the battery is measured.

In the third step S23, the current battery charge rate SOC is calculated as the charge rate calculation. The charging rate SOC calculated here is used for calculation of the stable voltage in the next step. The calculation of the charging rate SOC can be performed using (Equation 2) used in the discharge duration prediction. Note that ΔC used in the calculation of (Equation 2) can be calculated by integrating the discharge current after idling stop over time.

In the fourth step S24, the current stable voltage of the battery is estimated. The equation (4) used in the discharge duration prediction can be applied to the estimation of the stable voltage OCV. Here, the charge rate SOC used in the calculation of (Equation 4) is the one calculated in the third step S23.

In the fifth step S25, as the voltage drop amount calculation, the voltage drop amount ΔV from the stable voltage OCV is calculated using the voltage drop amount calculation formula created in the first step S21. When the engine is started, the current I shown in FIG. 7A and the internal resistance or internal impedance measured in the second step S22 are substituted into the voltage drop calculation formula of (Formula 1), for example, to reduce the voltage drop. The amount ΔV is calculated.

In the sixth step S26, when the engine is started at the present time by subtracting the voltage drop amount ΔV calculated in the fifth step S25 from the stable voltage OCV estimated in the fourth step S24 as a response voltage estimation calculation. Can be estimated.

In the seventh step S27, the response voltage V estimated in the sixth step S26 is compared with the operation limit voltage Vth, and when the response voltage V is sufficiently higher than the operation limit voltage Vth (the difference between the two is larger than the minute value ε). Terminates monitoring. When the response voltage V is sufficiently close to the operation limit voltage Vth (the difference between the two is a minute value ε or less), it is determined that the response voltage V has reached the operation limit voltage Vth, and predetermined load control is performed in the eighth step S28. I do.

As the load control performed in the eighth step S28, there is a control of stopping the low priority load among the electrical loads that are operating even during idling stop. In this case, the electrical loads to be stopped may be all in operation, or the priority order of the electrical loads to be stopped in advance may be determined and stopped in order according to the priority order.

As another load control performed in the eighth step S28, there is a control for starting the engine immediately and starting charging the battery. By starting the engine immediately before the engine cannot be restarted, a situation in which the engine cannot be restarted can be avoided.

Also in the battery state detection method of the present embodiment, as in the case of the discharge duration prediction, the internal resistance or internal impedance used for calculating the voltage drop amount ΔV can be corrected by the charge capacity, the discharge current, the battery temperature, and the like. it can. By using the corrected internal resistance or internal impedance, the response voltage at the time of engine start can be estimated with higher accuracy, and the accuracy of battery load control can be improved.

An embodiment of the battery state detection device and the battery power supply system of the present invention to which the battery discharge duration prediction method and the battery state detection method described above are applied will be described below with reference to FIG. FIG. 9 is a block diagram showing a schematic configuration of the battery state detection device and the battery power supply system of the present embodiment. A battery power supply system 100 according to the present embodiment includes a battery 101, an alternator 102, a power supply control unit 103, and a battery state detection device 110 according to the present embodiment. The power control unit 103 controls the battery 101 and the alternator 102 that are power sources.

A load 200 is connected to the battery 101 and the alternator 102, and power is supplied from the alternator 102 to the load 200 while the engine is operating. Further, when the engine is not operating at an idling stop, power cannot be supplied from the alternator 102, so power is supplied from the battery 101 to the load 200. The power supply control unit 103 performs engine start / stop control and power supply control from the battery 101 or the alternator 102 to the load 200.

The battery state detection device 110 according to the present embodiment includes a battery state measurement unit 111 that inputs measurement values such as current, internal resistance or internal impedance, and temperature of the battery 101, and an arithmetic processing unit 120 that performs processing for state detection of the battery 101. And a storage unit 112 that stores measurement data, data necessary for arithmetic processing, and the like.

The arithmetic processing unit 120 includes a discharge duration prediction unit 121 and a state detection unit 122 in order to realize the functions of the discharge duration prediction and the state detection described above. Each means inputs the current, internal resistance, internal impedance, etc. of the battery 101 from the battery state measurement unit 111 and reads the fitting parameters used in the voltage drop calculation formula etc. from the storage unit 112 and performs a predetermined calculation. I do.

The discharge duration prediction means 121 uses the discharge duration prediction method of the embodiment described above to predict the discharge duration, for example, according to a request from the driver, and displays this on a predetermined display device (not shown). You can make it. Further, based on the predicted discharge duration, it is possible to cause the power supply control unit 103 to perform predetermined load control.

When the state detection unit 122 determines that load control is necessary, the state detection unit 122 outputs a load control request to the power supply control unit 103. The power supply control unit 103 performs load control such as stopping or reducing power supply to the load 200 or starting the engine in accordance with an instruction from the discharge duration prediction unit 121 or the state detection unit 122.

As explained above, discharge duration prediction method of the battery described above, the battery state detection process, the battery state detection device, and according to the battery power supply system, with respect to the battery during discharge, needed to operate the predetermined device It is possible to ensure a sufficient charge capacity.

Note that the description in the present embodiment shows an example of the battery discharge duration prediction method, the battery state detection method, the battery state detection device, and the battery power supply system described above, but is not limited thereto. The detailed configuration and detailed operation such as the battery discharge duration prediction method described above can be appropriately changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Load 100 Battery power supply system 101 Battery 102 Alternator 103 Power supply control part 110 Battery state detection apparatus 111 Battery state measurement part 112 Storage part 120 Operation processing part 121 Discharge duration prediction means 122 State detection means 200 Load

Claims (7)

A state detection method for a vehicle battery that supplies power to a load while the engine is stopped,
Create a voltage drop calculation formula in advance to calculate the voltage drop from the stable voltage due to discharge with the current value and internal resistance or impedance as variables,
Measure the current value and internal resistance or internal impedance of the battery,
Calculate the charging rate of the battery from the current value to estimate a stable voltage,
Substituting the current value for device operation, which is the current value when starting the engine, and the internal resistance or internal impedance into the voltage drop amount calculation formula to calculate the voltage drop amount,
Subtracting the voltage drop from the stable voltage to calculate a response voltage at the time of starting the engine,
Activating a predetermined load control when it is determined that the response voltage is equal to or lower than a predetermined threshold ;
In the battery state detection method,
Create in advance a calculation correlation equation of the internal resistance or internal impedance having a charging rate as a variable and having an adjustment parameter,
The adjustment parameter is determined by substituting the measured value of the internal resistance or internal impedance and the charging rate at the time of measuring the internal resistance or internal impedance into the calculated correlation equation,
The internal resistance or internal impedance is calculated by substituting the charging rate and the determined adjustment parameter into the calculated correlation formula, and the internal resistance or internal impedance is substituted into the voltage drop calculation formula in calculating the voltage drop amount. A battery state detection method comprising: A state detection method for a vehicle battery that supplies power to a load while the engine is stopped,
Create a voltage drop calculation formula in advance to calculate the voltage drop from the stable voltage due to discharge with the current value and internal resistance or impedance as variables,
Measure the current value and internal resistance or internal impedance of the battery,
Calculate the charging rate of the battery from the current value to estimate a stable voltage,
Substituting the current value for device operation, which is the current value when starting the engine, and the internal resistance or internal impedance into the voltage drop amount calculation formula to calculate the voltage drop amount,
Subtracting the voltage drop from the stable voltage to calculate a response voltage at the time of starting the engine,
Activating a predetermined load control when it is determined that the response voltage is equal to or lower than a predetermined threshold;
In the battery state detection method,
Create in advance a calculation correlation equation of the internal resistance or internal impedance having the current value as a variable and having an adjustment parameter,
The adjustment parameter is determined by substituting the measured value of the internal resistance or internal impedance and the discharge current value at the time of measuring the internal resistance or internal impedance into the calculated correlation equation,
The internal resistance or internal impedance is calculated by substituting the device operating current value and the determined adjustment parameter into the calculated correlation equation, and the internal resistance or internal impedance is calculated as the voltage drop amount in the calculation of the voltage drop amount. A battery state detection method characterized by substituting into an expression. A state detection method for a vehicle battery that supplies power to a load while the engine is stopped,
Create a voltage drop calculation formula in advance to calculate the voltage drop from the stable voltage due to discharge with the current value and internal resistance or impedance as variables,
Measure the current value and internal resistance or internal impedance of the battery,
Calculate the charging rate of the battery from the current value to estimate a stable voltage,
Substituting the current value for device operation, which is the current value when starting the engine, and the internal resistance or internal impedance into the voltage drop amount calculation formula to calculate the voltage drop amount,
Subtracting the voltage drop from the stable voltage to calculate a response voltage at the time of starting the engine,
Activating a predetermined load control when it is determined that the response voltage is equal to or lower than a predetermined threshold;
In the battery state detection method,
Create in advance a calculation correlation equation of the internal resistance or internal impedance with the temperature as a variable and having an adjustment parameter,
The adjustment parameter is determined by substituting the measured value of the internal resistance or internal impedance and the temperature at the time of measuring the internal resistance or internal impedance into the calculated correlation equation,
The internal resistance or internal impedance is calculated by substituting the battery temperature and the determined adjustment parameter into the calculated correlation formula, and the calculation of the voltage drop amount uses the internal resistance or internal impedance as the voltage drop amount calculation formula. A battery state detection method characterized by substituting. The load control is battery status detecting method as claimed in any one of claims 1 to 3, characterized in that a control for stopping the low priority device. A state detection method for a vehicle battery that supplies power to a load while the engine is stopped,
Create a voltage drop calculation formula in advance to calculate the voltage drop from the stable voltage due to discharge with the current value and internal resistance or impedance as variables,
Measure the current value and internal resistance or internal impedance of the battery,
Calculate the charging rate of the battery from the current value to estimate a stable voltage,
Substituting the current value for device operation, which is the current value when starting the engine, and the internal resistance or internal impedance into the voltage drop amount calculation formula to calculate the voltage drop amount,
Subtracting the voltage drop from the stable voltage to calculate a response voltage at the time of starting the engine,
Activating a predetermined load control when it is determined that the response voltage is equal to or lower than a predetermined threshold;
In the battery state detection method,
The load control is a control for starting the engine and starting charging the battery. A battery state measurement unit for measuring at least internal resistance or internal impedance of the battery;
A storage unit for storing a current value for device operation, which is a current value when the engine is started,
Input the battery current value and internal resistance or internal impedance from the battery state measurement unit, calculate the battery charge rate from the current value to estimate a stable voltage, and read the device operation from the storage unit Subtracting the voltage drop amount from the stable voltage and subtracting the voltage drop amount from the stable voltage, and subtracting the voltage drop amount from the stable voltage A calculation unit that calculates a response voltage and activates a predetermined load control when it is determined that the response voltage is equal to or lower than a predetermined threshold;
Equipped with a,
The said calculation control part starts the said engine as said load control, and starts the charge to the said battery, The battery state detection apparatus characterized by the above-mentioned . A battery power supply system comprising the battery state detection device according to claim 6 and a battery.

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