JP2007064871A - Approximate expression calculation device, its method, and discharge possible capacity prediction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant determination device for determining an unknown constant in a relationship expression of an arbitrary discharge current and a discharge continuation time even when the discharge continuation time to a large current estimated on the basis of discharge characteristics is 0 or less, and to provide its method and a discharge possible capacity prediction device using the constant determination device. <P>SOLUTION: CPU 23a estimates large and small two currents I1 of specific size and the discharge continuation time t1 on the basis of a discharge current and a terminal voltage measured during discharge of a battery 13. The discharge continuation times corresponding to the large and small two currents and the estimated large and small two currents are substituted for a Peuckert expression (I<SP>n</SP>×t=C) to determine unknown constants n and C. In addition, In CPU 23a, when the discharge continuation time to the large current is 0 or less, a prescribed positive value is substituted for the relationship expression in place of the discharge continuation time corresponding to the large current to determine the unknown constants n and C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an approximate expression calculation apparatus and method, and a relationship between a discharge current of a battery and a discharge duration during which the discharge current can be continuously discharged. The present invention relates to an apparatus for obtaining an approximate expression approximated by a relational expression indicating that a product of the discharge duration is a second constant, a method thereof, and a dischargeable capacity estimation apparatus using the apparatus.

FIG. 11 is a graph showing a relationship between an arbitrary discharge current I of the battery and a discharge duration t in which the arbitrary discharge current I can be sustained. As can be seen from the figure, the discharge duration t decreases exponentially as the discharge current I increases. It is disclosed that the relationship between the arbitrary discharge current I and the discharge duration t can be accurately approximated by the Pokert equation (= relational equation) shown in the following equation (1) (Patent Document 1).
^{I n · t = C ... (} 1)

  N (= first constant) in the equation is a guideline indicating the extent to which the discharge duration varies depending on the discharge current. As n increases, the decrease in the discharge duration t with respect to the increase in the discharge current I increases. In a normal lead battery, n is about 1.1 to 1.4. C (= second constant) is a measure of the dischargeable capacity of the battery. The larger the dischargeable capacity, that is, the longer C, the longer the discharge duration t.

  If these constants n and C are obtained, the discharge duration t for an arbitrary discharge current I can be obtained, and the dischargeable capacity (Ah) is known from the product of the arbitrary discharge current I and the obtained discharge duration t. be able to. The constants n and C described above can be expressed by the above equation (1) if at least two data pairs (I, t) including the discharge current I and the discharge duration t that can sustain the discharge current I can be obtained. The constants n and C can be obtained by substituting the data pair (I, t) into the Poikert equation shown or approximating two or more data pairs (I, t) using the least square method. .

  Therefore, Patent Document 1 discloses discharge durations t1 and t2 corresponding to specific large and small two currents I1 and I2 based on discharge characteristics obtained from a data pair of discharge current and terminal voltage measured during battery discharge. It is described that the constants n and C are calculated by substituting the estimated data pair (I1, t1) and (I2, t2) into the Pojkert equation. As the above-described large and small 2 currents, a maximum current in discharge and a small current of about 1/100 of the maximum current are used.

The discharge durations t1 and t2 corresponding to specific large and small two currents I1 and I2 are estimated as follows. First, based on the discharge characteristics obtained from the data pair of the discharge current and the terminal voltage measured during the battery discharge, the voltage drop generated when the large and small two discharge currents I1 and I2 are passed through the internal resistance of the battery is estimated. Then, by subtracting the capacity that cannot be discharged due to the voltage drop and the capacity that needs to be left at the end of the discharge from the charge capacity of the battery, the dischargeable capacity X1, X2 for the large and small discharge currents is estimated, and the estimated dischargeable capacity Values obtained by dividing X1 and X2 by two currents I1 and I2 are estimated as discharge durations t1 and t2.
JP 2004-301784 A

  However, in the above-described conventional dischargeable capacity estimation device, when the dischargeable capacity for the estimated large current is 0 or a value smaller than 0, the discharge duration obtained by dividing this dischargeable capacity by the large current is also obtained. It becomes 0 or a value smaller than 0. As described above, when two or more estimated data pairs (I, t) include one having a discharge duration t of 0 or 0 or less, the data pairs (I, t) are approximated and the Pokert is approximated. Cannot be obtained.

  For example, if the estimated data pair is (I1, 0), (I2, t2), as shown in FIG. 12, the two data pairs (I1, 0), (I2, t2) The passing curve L1 needs to be approximated by the Pojkert equation. However, as can be seen from the equation (1), the Poikert equation described above represents a curve that passes the discharge duration t = 0 or less in a region where the discharge current I is larger than 0 as shown by the curve L1. Can not. In other words, the formula for obtaining constants n and C from two or more data pairs (I, t) is a logarithm and cannot give an answer.

  Therefore, it is conceivable to approximate a data pair obtained by excluding the estimated two or more data pairs (I, t) with a discharge duration of 0 or less by the Pokert equation. However, as shown in FIG. 12, when the data pair (I1, 0) whose discharge duration is 0 or less is excluded, the data pair becomes one of (I1, t1). Poikert equations cannot be obtained from data pairs. For this reason, for example, as shown in FIG. 12, the dischargeable capacity cannot be estimated even though the discharge duration at the desired discharge current I (<I1) is not zero and the dischargeable capacity is not zero. The problem also arises.

  Therefore, the present invention pays attention to the above problems, and among the data pairs composed of two or more discharge currents and discharge durations estimated based on the discharge characteristics, there are data pairs whose discharge duration is greater than zero. Approximate expression calculation apparatus and method capable of approximating the relationship between an arbitrary discharge current and discharge duration even if there is only one by the Pokert's equation (= relational equation), and calculation of the approximate equation An object is to provide a dischargeable capacity estimation device using the device.

  The invention according to claim 1, which has been made to solve the above-mentioned problems, shows the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be discharged continuously, as a first constant of the discharge current. A device for obtaining an approximate expression approximated by a relational expression indicating that a product of the power and the discharge duration is a second constant, and specified based on a discharge current and a terminal voltage measured during discharging of the battery Specific discharge duration estimation means for estimating a discharge duration corresponding to each of a plurality of discharge currents of the size, and the estimated corresponding to the discharge current of the specific size and the discharge current of the specific size An approximate expression calculating means for obtaining an approximate expression obtained by approximating a plurality of data pairs consisting of discharge durations by the relational expression, wherein the approximate expression calculating means is data having a discharge duration of 0 or less among the plurality of data pairs. Pair When there is at least one, instead of the data pair having the discharge duration of 0 or less, the minimum discharge current and the predetermined positive discharge duration among the discharge currents constituting the data pair having the discharge duration of 0 or less The approximate expression calculating apparatus is characterized in that the approximate expression is obtained using a data pair consisting of:

  According to a fourth aspect of the present invention, the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is expressed by the product of the first constant power of the discharge current and the discharge duration. Is a method for obtaining an approximate expression approximated by a relational expression indicating that it is a second constant, and for each of a plurality of discharge currents having a specific magnitude based on the discharge current and the terminal voltage measured during the discharge of the battery. A corresponding discharge duration is estimated, and a plurality of data pairs including the estimated discharge duration and the estimated discharge duration corresponding to the specific magnitude of the discharge current are approximated by the relational expression. An approximate expression is obtained, and when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, the discharge duration is 0 or less instead of the data pair having a discharge duration of 0 or less. Data pair Lies in the approximate expression calculation method characterized by determining the approximate equation using the minimum discharge current and the data pair consisting of a predetermined positive discharge duration of the discharge current to be formed.

  According to the first and fourth aspects of the present invention, the discharge duration corresponding to each of the plurality of discharge currents having a specific magnitude is estimated based on the discharge current and the terminal voltage measured during the battery discharge. A plurality of data pairs consisting of a discharge current of a specific magnitude and a discharge duration estimated corresponding to the discharge current of the specific magnitude are represented by a product of the first constant power of the discharge current and the discharge duration. An approximate expression is obtained by approximating with a relational expression indicating that it becomes two constants. In addition, when there is at least one data pair having a discharge duration of 0 or less among a plurality of data pairs, a discharge that constitutes a data pair having a discharge duration of 0 or less instead of a data pair having a discharge duration of 0 or less An approximate expression is obtained by approximating with the above relational expression using a data pair consisting of a minimum discharge current of a current and a predetermined positive discharge duration. Therefore, even when there is only one data pair having a discharge duration greater than 0, instead of a data pair having a discharge duration of 0 or less, the discharge currents constituting the data pair having a discharge duration of 0 or less A data pair consisting of the minimum discharge current and a predetermined positive discharge duration close to 0, for example, can be used, and an approximate expression approximated by the above relational expression can be obtained accurately.

  According to a second aspect of the present invention, the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is expressed as the product of the first constant power of the discharge current and the discharge duration. Is an apparatus that obtains an approximate expression approximated by a relational expression indicating that the second constant is obtained, wherein each of a plurality of discharge currents having a specific magnitude is determined based on the discharge current and the terminal voltage measured during the discharge of the battery. A specific discharge duration estimating means for estimating a corresponding discharge duration; and a plurality of data pairs comprising the discharge current of the specific magnitude and the estimated discharge duration corresponding to the discharge current of the specific magnitude. Approximate expression calculating means for obtaining the approximate expression by approximating the above with a functional expression, wherein the approximate expression calculating means has at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, Said discharge A discharge current whose duration is 0 is estimated, and instead of a data pair whose discharge duration is 0 or less, a data pair consisting of a discharge current whose estimated discharge duration is 0 and a predetermined positive discharge duration The approximate expression calculating apparatus is characterized by obtaining the approximate expression using

  According to a fifth aspect of the present invention, the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is expressed as the product of the first constant power of the discharge current and the discharge duration. Is a method for obtaining an approximate expression approximated by a relational expression indicating that it is a second constant, and for each of a plurality of discharge currents having a specific magnitude based on the discharge current and the terminal voltage measured during the discharge of the battery. A corresponding discharge duration is estimated, and a plurality of data pairs including the estimated discharge duration and the estimated discharge duration corresponding to the specific magnitude of the discharge current are approximated by a functional expression. The approximate expression is obtained, and when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, a discharge current at which the discharge duration is 0 is estimated, and the discharge duration is 0 or less. Data pair Ri to, consists in the approximate expression calculation method characterized by using said estimated discharge duration becomes zero discharge current and the data pair consisting of a predetermined positive discharge duration determining the approximate expression.

  According to the second and fifth aspects of the invention, the discharge duration corresponding to each of a plurality of discharge currents having a specific magnitude is estimated based on the discharge current and the terminal voltage measured during the battery discharge. A plurality of data pairs consisting of a discharge current of a specific magnitude and a discharge duration estimated corresponding to the discharge current of the specific magnitude are represented by a product of the first constant power of the discharge current and the discharge duration. An approximate expression is obtained by approximating with a relational expression indicating that it becomes two constants. Further, when there is at least one data pair having a discharge duration of 0 or less among a plurality of data pairs, a discharge current with a discharge duration of 0 is estimated, and instead of a data pair having a discharge duration of 0 or less, An approximate expression is obtained using a data pair consisting of a discharge current at which the estimated discharge duration is zero and a predetermined positive discharge duration. Therefore, even when there is only one data pair with a discharge duration greater than 0, instead of a data pair with a discharge duration of 0 or less, a discharge current with an estimated discharge duration of 0 and a predetermined positive Thus, an approximate expression approximated by the above relational expression can be obtained.

  According to a third aspect of the present invention, the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is expressed as the product of the first constant power of the discharge current and the discharge duration. Is an apparatus that obtains an approximate expression approximated by a relational expression indicating that the second constant is obtained, wherein each of a plurality of discharge currents having a specific magnitude is determined based on the discharge current and the terminal voltage measured during the discharge of the battery. Specific dischargeable capacity estimation means for estimating a corresponding dischargeable capacity and obtaining a plurality of dischargeable capacity data pairs comprising the discharge current of the specific magnitude and the dischargeable capacity estimated corresponding to the discharge current; A discharge comprising a discharge current having a specific magnitude and a discharge duration obtained by dividing the estimated dischargeable capacity corresponding to the discharge current by the discharge current from the plurality of dischargeable capacity data pairs. Persistence An approximate expression calculating means for obtaining an approximate data that is obtained by approximating the obtained discharge duration data pair with the functional expression, and the approximate expression calculating means is a discharge duration of the plurality of data pairs. When there is at least one data pair whose time is 0 or less, a capacity difference between a predetermined positive dischargeable capacity and any one of the dischargeable capacity constituting the dischargeable capacity data pair is obtained, and the plurality of discharges are possible Instead of the capacity data pair, the dischargeable capacity is greater than 0 among the plurality of additional dischargeable capacity data pairs obtained by adding the capacity difference to each of the dischargeable capacity constituting the plurality of dischargeable capacity data pairs. In the approximate expression calculation apparatus, the discharge duration data pair is obtained from a larger additional dischargeable capacity data pair.

  According to a sixth aspect of the present invention, the relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is expressed as the product of the first constant power of the discharge current and the discharge duration. Is a method for obtaining an approximate expression approximated by a relational expression indicating that it is a second constant, and for each of a plurality of discharge currents having a specific magnitude based on the discharge current and the terminal voltage measured during the discharge of the battery. A corresponding dischargeable capacity is estimated, a plurality of dischargeable capacity data pairs including a discharge current of the specific magnitude and a dischargeable capacity estimated corresponding to the discharge current are obtained, and the plurality of dischargeable capacity data From the pair, a discharge duration data pair consisting of the discharge current of the specific magnitude and the discharge duration obtained by dividing the estimated dischargeable capacity by the discharge current corresponding to the discharge current is obtained, Sought The approximation formula obtained by approximating the power duration data pair with the functional formula is obtained, and when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, a predetermined positive dischargeable capacity and the A difference in capacity from any one of the dischargeable capacities constituting the dischargeable capacity data pair is obtained, and each of the dischargeable capacities constituting the plurality of dischargeable capacity data pairs instead of the plurality of dischargeable capacity data pairs. The discharge duration data pair is obtained from an additional dischargeable capacity data pair whose dischargeable capacity is greater than 0 among a plurality of additional dischargeable capacity data pairs obtained by adding the capacity difference to Approximate formula calculation method.

  According to invention of Claim 3 and 6, the dischargeable capacity | capacitance corresponding to each of several discharge current of specific magnitude | size is estimated based on the discharge current and terminal voltage which were measured during discharge of a battery, and specific magnitude | size is estimated. A plurality of dischargeable capacity data pairs including the discharge current and the dischargeable capacity estimated corresponding to the discharge current are obtained. A discharge duration data pair comprising a discharge current of a specific magnitude and a discharge duration obtained by dividing the dischargeable capacity estimated corresponding to the discharge current by the discharge current from a plurality of dischargeable capacity data pairs. And the approximate expression obtained by approximating the obtained discharge duration data pair with a functional expression.

  Further, when there is at least one data pair having a discharge duration of 0 or less among a plurality of data pairs, the capacity of any one of a predetermined positive dischargeable capacity and a dischargeable capacity constituting the dischargeable capacity data pair Discharge among a plurality of additional dischargeable capacity data pairs obtained by calculating a difference and adding a capacity difference to each of the dischargeable capacity constituting the plurality of dischargeable capacity data pairs instead of the plurality of dischargeable capacity data pairs. A discharge duration data pair is obtained from an additional dischargeable capacity data pair whose possible capacity is greater than zero. Therefore, even if there is only one data pair with a discharge duration greater than 0, the discharge duration data pair obtained by adding the capacity has at least two data pairs with a discharge duration greater than 0. is there. For this reason, an approximate expression can be calculated | required using the 2 or more addition data more than the discharge duration more than 0 among discharge duration data.

  Invention of Claim 7 calculates | requires the discharge duration with respect to arbitrary discharge currents using the approximate expression calculation apparatus of Claim 1, 2, or 3, and the approximate expression calculated by the said approximate expression calculation means, A dischargeable capacity estimation apparatus comprising dischargeable capacity estimation means for estimating a dischargeable capacity of the battery from a value obtained by multiplying an arbitrary discharge current and the obtained discharge duration.

  According to the invention described in claim 7, the dischargeable capacity estimation means obtains the discharge duration for an arbitrary discharge current using the approximate expression obtained by the approximate expression calculation device according to claim 1, 2 or 3, The dischargeable capacity of the battery is estimated from a value obtained by multiplying an arbitrary discharge current and the obtained discharge duration. Therefore, even if there is only one data pair having a discharge duration longer than 0 among a plurality of data pairs, an approximate expression can be obtained to estimate the dischargeable capacity for an arbitrary discharge current. .

  The invention according to claim 8 is the dischargeable capacity estimation device according to claim 7, wherein the dischargeable capacity estimation means is configured such that the discharge durations for the plurality of discharge currents estimated by the specific discharge duration estimation means are all zero. In the case of the following, the dischargeable capacity estimation device is characterized in that the dischargeable capacity corresponding to an arbitrary discharge current is estimated as zero.

  According to the invention described in claim 8, the dischargeable capacity estimation means is a discharge corresponding to an arbitrary discharge current when the discharge durations for the plurality of discharge currents estimated by the specific discharge duration estimation means are all 0 or less. Estimate possible capacity to be zero. Therefore, it is possible to estimate an accurate dischargeable capacity without calculating an approximate expression.

  The invention according to claim 9 is the dischargeable capacity estimation device according to claim 7 or 8, wherein the dischargeable capacity estimation means has at least data having a discharge duration of 0 or less among the plurality of data pairs. When there is one, the discharge current at which the discharge duration is zero is estimated, and when the arbitrary discharge current is equal to or greater than the discharge current at which the estimated discharge duration is zero, the discharge current corresponds to the arbitrary discharge current It exists in the dischargeable capacity | capacitance estimation apparatus characterized by estimating dischargeable capacity | capacitance as 0.

  According to the ninth aspect of the present invention, the dischargeable capacity estimating means calculates a discharge current at which the discharge duration becomes 0 when there is at least one data having a discharge duration of 0 or less among the plurality of data pairs. If the estimated discharge duration is equal to or greater than the discharge current at which the arbitrary discharge current is zero, the dischargeable capacity corresponding to the arbitrary discharge current is estimated to be zero. Accordingly, it is possible to estimate an accurate dischargeable capacity corresponding to the magnitude of an arbitrary discharge current.

  As described above, according to the inventions of claims 1 and 4, even if there is only one data pair having a discharge duration greater than 0, instead of a data pair having a discharge duration of 0 or less, By using a data pair consisting of a minimum discharge current among the discharge currents constituting a data pair having a discharge duration of 0 or less and a predetermined positive discharge duration which is close to 0, for example, the first of the discharge currents can be accurately determined. An approximate expression approximated by a relational expression indicating that the product of the constant power and the discharge duration is the second constant is obtained.

  According to the second and fifth aspects of the invention, even when there is only one data pair having a discharge duration greater than 0, the estimated discharge duration is used instead of the data pair having a discharge duration of 0 or less. Is a relational expression showing that the product of the first constant power of the discharge current and the discharge duration becomes a second constant accurately by using a data pair consisting of a discharge current with zero and a predetermined positive discharge duration. An approximate expression approximated by can be obtained.

  According to the third and sixth aspects of the present invention, even when there is only one data pair having a discharge duration greater than 0, the discharge duration data pair obtained by adding the capacity includes the discharge duration time. There are at least two data pairs greater than zero. For this reason, the product of the first constant power of the discharge current and the discharge duration is accurately set to the second constant using at least two or more additional data greater than 0 in the discharge duration data. An approximate expression approximated by a relational expression indicating

  According to the seventh aspect of the present invention, even when there is only one data pair having a discharge duration longer than 0 among a plurality of data pairs, an approximate expression is obtained and a discharge for an arbitrary discharge current is performed. Since a possible capacity | capacitance can be estimated, the dischargeable capacity | capacitance with respect to the arbitrary discharge current to obtain | require correctly can be estimated.

  According to the invention described in claim 8, it is possible to estimate an accurate dischargeable capacity without calculating an approximate expression.

  According to the ninth aspect of the present invention, it is possible to estimate an accurate dischargeable capacity corresponding to an arbitrary discharge current.

First Embodiment Hereinafter, a battery approximate expression calculation apparatus and method, and a dischargeable capacity estimation apparatus according to the present invention will be described with reference to the drawings. First, the basic concept of the dischargeable capacity estimation apparatus using the approximate expression calculation method of the present invention will be described with reference to FIGS.

  In general, the battery discharge duration (service life) varies depending on the discharge current and temperature, and also varies depending on the specific electrolyte density of the battery, but the relationship between the discharge current and the discharge duration can be approximated by the Pojkert equation. Are known.

The Pokert's equation is expressed as the following equation (1).
^{I n · t = C ... (} 1)
In the equation, I is a discharge current, t is a discharge duration which is a time during which discharge with the discharge current I can be continued, and n and C are unknown constants determined from discharge data. According to the Pokert equation, the product of the nth power of the discharge current I and the discharge duration t is a constant value C. That is, n can be said to be a standard indicating the extent to which the discharge duration varies depending on the discharge current. As n increases, the decrease in the discharge duration t with respect to the increase in the discharge current I increases. In a normal lead battery, n is about 1.1 to 1.4. C can be said to be a measure of the dischargeable capacity of the battery. The larger the dischargeable capacity, that is, the longer C, the longer the discharge duration t. As is clear from the above, n corresponds to the first constant in the claims, and C corresponds to the second constant in the claims.

  If the unknown constants n and C in the equation (1) are obtained, the discharge duration t for an arbitrary discharge current I can be obtained, and discharge is possible by the product of the arbitrary discharge current I and the obtained discharge duration t. The capacity (Ah) can be known.

  When the relationship between at least two discharge currents I1 and I2 and the discharge durations t1 and t2 corresponding to the discharge currents is clear, these two data pairs (I1, t1) and (I2, t2) By approximation, a Pojkert equation that approximates the relationship between the discharge current I and the discharge duration t can be obtained. As a method for obtaining the above-described Pokert's equation, for example, a method for obtaining constants n and C by substituting the data pair (I1, t1), (I2, t2) into the Pokert's equation shown in Equation (1), and data There is a method of approximating the pair (I1, t1) (I2, t2) using the least square method.

First, a method of obtaining the constants n and C by substituting the data pair (I1, t1) and (I2, t2) into the Poikert equation shown in the equation (1) will be described. The above equation (1) can be rewritten as the following equation (2).
logt = −nlogI + C ′ (2)
Here, C ′ = logC.

Now, substituting equation (2) for the discharge currents I1 and I2 and the discharge durations t1 and t2 for the discharge current, the following two equations can be generated.
logt1 = −nlogI1 + C ′
logt2 = −nlogI2 + C ′
Taking the difference between both sides of these two equations, the following equation is obtained.
logt1-logt2 = -nlogI1 + nlogI2
Rewriting this equation yields:
log (t1 / t2) = nlog (I2 / I1)
n = log (t1 / t2) / log (I2 / I1) (3)
C = I1 ⁿ · t1 = I2 ⁿ · t2 (4)

このように定数ｎ、Ｃが決定されたポイケルトの式を、放電電流Ｉと放電持続時間ｔとの関係を示す近似式として得ることができる。 The above-described method can be used only when approximating two data pairs. However, if the least square method described later is used, three or more data pairs can also be approximated by Pojkert's equation. More specifically, when the relationship between m discharge currents I1 ... Im and discharge durations t1 ... tm corresponding to the discharge currents I1 ... Im is clear, these m data pairs (I1, t1) ... (Im , Tm) is substituted into the following formula to determine the constants n and C.

Thus, the Pokert equation in which the constants n and C are determined can be obtained as an approximate equation indicating the relationship between the discharge current I and the discharge duration t.

  In addition, the dischargeable capacity (Ah) that the battery can actually discharge to the load is determined from the charge capacity (current-time product) corresponding to the open circuit voltage of the battery, the capacity that must be left at the end of discharge, It can also be said that the remaining capacity is obtained by subtracting the capacity corresponding to the voltage drop generated inside the battery, that is, the capacity that cannot be discharged due to the voltage drop. The terminal voltage of the battery indicates the voltage value reflecting the state of charge of the battery, and not only differs between its internal state, that is, when it is in an equilibrium state and when it is in an unbalanced state, but also due to the discharge current flowing from the battery It is also known to take a value reflecting a voltage drop generated inside the battery. Therefore, the dischargeable capacities X1 and X2 corresponding to the two discharge currents I1 and I2 described above are estimated from the data pair of the discharge current and the terminal voltage measured at the high rate discharge, and the estimated dischargeable capacities X1 and X2 are calculated as the two discharge currents. By dividing by I1 and I2, respectively, the discharge durations t1 and t2 can be estimated. This estimation method will be described below.

  For example, in an in-vehicle battery, discharge is performed through a starter motor when the engine is started. At this time, the maximum current value that is much larger than the steady current value, generally called inrush current, increases in a short time. A discharge current that decreases in a short time from the maximum current value to the steady current value flows. In general, such a discharge current is called a high rate discharge, and an approximation process using, for example, a least square method is performed on a data pair obtained by measuring the discharge current and the battery terminal voltage at the high rate discharge by high-speed sampling. When a quadratic approximate curve is obtained and plotted on a graph with the horizontal axis representing the discharge current and the vertical axis representing the terminal voltage, a characteristic curve showing the relationship between the discharge current and the terminal voltage as shown in FIG. 1 is drawn.

  Among the second-order approximate characteristic curves, the terminal voltage drop caused by the increase in discharge current that appears in the characteristic curve in the direction of current increase includes various voltage drops due to the internal resistance of the battery. Focusing on the current axis of the current (peak current) Ip, the breakdown of the voltage drop will be examined, and a method for obtaining the dischargeable capacity at the two currents of the maximum current Ip and the small current I0 will be described.

  First, the voltage drop at the maximum current Ip includes a voltage drop (Rj × Ip) due to the maximum current Ip flowing through the internal pure resistance Rj (ohmic resistance) in the state of charge of the battery at that time. The internal pure resistance Rj is obtained by, for example, analyzing two quadratic approximate curves (two when the discharge current increases and when the discharge current decreases) obtained by the data pair obtained by sampling during the high rate discharge described above. However, detailed description of the specific method is omitted here.

  Next, the voltage drop other than the voltage drop (Rj × Ip) due to the pure resistance is a voltage drop due to polarization generated in the battery. Therefore, by removing the voltage drop due to the pure resistance from the secondary approximate characteristic curve of the discharge current-terminal voltage, a secondary approximate characteristic curve of the polarization voltage drop with respect to the discharge current can be obtained.

  According to David Linden's “Latest Battery Handbook”, P10 Figure 2.1 “Cells as a Function of Operating Current”, when a large amount of discharge current flows, the polarization becomes a constant value according to the magnitude. It can be said that there is a saturation polarization voltage drop that saturates.

  Therefore, the maximum voltage drop of the second-order approximate characteristic curve of the polarization voltage drop is defined as a saturation polarization voltage drop Vpip at the maximum current Ip. Further, the saturation polarization voltage drop Vpip at the maximum current Ip is divided by the current value Ipol (see FIG. 2) at that point to obtain the polarization voltage drop per unit discharge current, and then the small current at the high rate discharge is added thereto. By multiplying, the saturation polarization voltage drop, which is the maximum polarization voltage drop at a small current, can be obtained. A specific method for obtaining the saturation polarization voltage drop will be described later together with a method for obtaining a second-order approximate characteristic curve of the polarization voltage drop.

  Therefore, the maximum voltage drop generated inside the battery when the discharge with the maximum current Ip is continued is the voltage drop (Rj × Ip) due to the current internal pure resistance Rj, and the saturation polarization voltage drop at the maximum current Ip. The sum of Vpip is estimated as the total voltage drop Vmax. When such a voltage drop occurs in the battery, the amount of electricity that can be discharged is reduced by this voltage drop.

On the other hand, the current circuit voltage OCVn of the battery is estimated or measured from the terminal voltage before the start of discharge. The current open circuit voltage OCVn is a voltage corresponding to the amount of electricity currently stored in the battery, that is, the charge capacity. Therefore, the remaining voltage obtained by subtracting the total voltage drop Vmax and the discharge end voltage Ve described above from the current open circuit voltage OCVn can be said to be a voltage according to the dischargeable capacity (Ah). Therefore, the ADC rate (%) is obtained using the following equation.
ADC rate = {(OCVn−Vmax−Ve) / (Vf−Ve)} × 100% (7)
However, in the above equation, Vf is a fully charged voltage when new, Ve is a discharge end voltage when new, and both can be obtained from the design value of the battery.

Further, a value obtained by multiplying the obtained ADC rate (%) by the difference (ΔSOC) between the amount of electricity SOCf corresponding to the full charge voltage Vf and the amount of electricity SOCe corresponding to the discharge end voltage Ve is obtained at the time of high rate discharge. It is estimated as the amount of electricity (ADCip (Ah)) that can be discharged when the discharge continues at the maximum current Ip.
ADCip = ADC rate × ΔSOC (8)
The SOCf and SOCe described above can also be obtained from the design value of the battery.

  Further, for a plurality of discharge currents having a magnitude equal to or smaller than the maximum current Ip, the dischargeable capacity is estimated by the same method as that for the small current described above (a method of calculating the saturation polarization voltage by Vpip / Ipol · I), As a result of plotting, a straight line as indicated by A in FIG. 3 was obtained. When this is compared with the curve B showing the relationship between the measured discharge currents and the amount of electricity that can be discharged, the maximum current Ip is sufficiently smaller than this, for example, a small current I0 of 1/100 or less. It was confirmed that the estimated value and the actually measured value are very close to each other.

  Accordingly, the maximum current Ip at the time of high rate discharge and the relatively small predetermined small current I0 having a high degree of coincidence with the experimentally measured value are set as the above-described two currents I1 and I2, and each current is as described above. The dischargeable capacities X1 and X2 estimated as described above are obtained, and the obtained dischargeable capacities X1 and X2 are divided by I1 and I2 to obtain discharge durations t1 (= X1 / I1) and t2 (= X2 / I2), The two data pairs (I1, t1) and (I2, t2) obtained in this way are approximated by Pojkert's equation. In this figure, the curve C obtained by this determination is also plotted, but the estimated curve C and the actual measurement curve B of the dischargeable capacity with respect to the discharge current in a wide range from the minimum current to the maximum current are very It was confirmed that Therefore, this current is predetermined as a small current of the two currents.

The second-order approximate characteristic curve of the polarization voltage drop described above is obtained by removing the voltage drop due to the pure resistance Rj from the second-order approximate characteristic curve of the discharge current-terminal voltage when the current increases, and is shown in FIG. Thus, the obtained second-order approximate characteristic curve of the polarization voltage drop is V = aI ² + bI + c
And This terminal voltage V of the battery represents a voltage drop Vo due to an internal resistance other than the pure resistance Rj of the battery.

From this equation, the following equation is obtained by differentiating the voltage drop ΔV / ΔI due to the internal resistance other than the pure resistance per unit current.
ΔV / ΔI = 2aI + b

Since the point where ΔV / ΔI of this equation becomes zero is the maximum value of the approximate curve,
0 = 2aI + b
The following formula is obtained, and when this formula is arranged,
I = −b / 2a
It becomes.

  Therefore, by substituting this current value I into an approximate expression representing a second-order approximate characteristic curve of the polarization voltage drop, a saturation polarization voltage drop (Vpip) that is the maximum polarization voltage drop at the maximum current Ip can be obtained.

  When the discharge starts from a non-equilibrium state where some polarization remains, the voltage corresponding to the difference between the open circuit voltage OCV in the equilibrium state estimated at the start of the discharge and the terminal voltage is approximated as described above. Since it is not included in the polarization voltage drop at the maximum current Ip obtained from the equation, the saturation polarization voltage drop needs to be added to the saturation polarization voltage drop (Vpip) at the maximum current obtained from the approximate equation.

  On the other hand, with respect to the saturation polarization voltage drop at a small current, the saturation polarization voltage drop (Vpip), which is the maximum polarization voltage drop at the maximum current Ip, is divided by the current value at that point to obtain a polarization voltage drop per unit discharge current. And a saturation polarization voltage drop, which is the maximum polarization voltage drop at a small current, can be obtained by multiplying this by a small current value during high rate discharge.

  When the discharge starts from the non-equilibrium state where some polarization remains, as in the case of the maximum current, it corresponds to the difference between the open circuit voltage OCV in the equilibrium state estimated at the start of the discharge and the terminal voltage. It is necessary to add the voltage to be added to the saturation polarization voltage drop at a small current as the saturation polarization voltage drop.

  By the way, as a result of estimating the dischargeable capacity corresponding to the above-described maximum current Ip, as shown in FIG. 4, the dischargeable capacity corresponding to the maximum current Ip is 0 (Ah) or less, and the discharge duration is 0 (s). May be: As described above in the prior art, the Pokert's equation cannot approximate the relationship in which the discharge current I passes through the discharge duration t = 0 or less in the region where the discharge current I is larger than 0 as shown by the curve L1. In addition, in this case, there is only one data pair (I0, t0) whose discharge duration is greater than 0, and a Pokert equation cannot be obtained from this one data pair (I0, t0).

  Therefore, as shown in FIG. 4, a discharge current Iα corresponding to a discharge duration of 0 (s), that is, a dischargeable capacity of 0 (Ah) is estimated. The dischargeable capacity corresponding to the discharge current Iα is 0 (Ah), but the constants n and C can be obtained by substituting this into the equations (3) and (4) or (5) and (6). Therefore, in the present embodiment, the discharge duration t (= Xα / Iα) is obtained with a positive value Xα that is close to a predetermined zero as much as the dischargeable capacity, and these data pairs (Iα, Xα / Iα) are obtained as data. Instead of the pair (Ip, tp), the constants n and C are obtained by substituting into the equations (3) and (4) or the equations (5) and (6). As is clear from this, Xα / Iα corresponds to the predetermined positive discharge duration in the claims.

  In FIG. 4, a curve L21 is a curve representing a Pokert's equation obtained from a data pair (I0, t0), (Iα, Xα / Iα). As shown in the figure, as Xα / Iα, that is, the dischargeable capacity Xα, the closer to 0, the closer the curve L21 is to the curve L1 and the higher the accuracy, but for convenience of calculation, for example, 0.01 ( Ah). Further, for example, 1 / 100th of the dischargeable capacity corresponding to the small current I0 may be considered as the dischargeable capacity Xα.

Next, a method for estimating the discharge current Iα will be described. The discharge current Iα at which the dischargeable capacity becomes 0 is a discharge current at which the ADC rate of the above-described equation (7) becomes 0, and the following equation (9) is obtained.
OCVn−Vmax (= Rj × Iα + Vpip) −Ve = 0 (9)
OCVn−Rj × Iα−Vpip−Ve = 0
Iα = (OCVn−Vpip−Ve) / Rj

  FIG. 5 is an explanatory diagram partially showing in block form the schematic configuration of the in-vehicle battery dischargeable capacity estimation device according to an embodiment of the present invention to which the battery constant determination method of the present invention is applied. The apparatus of this embodiment shown is mounted on a hybrid vehicle having a motor generator 5 in addition to the engine 3.

  In this hybrid vehicle, normally, only the output of the engine 3 is transmitted from the drive shaft 7 to the wheels 11 through the differential case 9 and travels. When the load is high, the motor generator 5 is driven by the electric power from the battery 13. In addition to the output of the engine 3, the output of the motor generator 5 is transmitted from the drive shaft 7 to the wheels 11 to perform assist traveling.

  In addition, this hybrid vehicle is configured to cause the motor generator 5 to function as a generator (generator) during deceleration or braking and to convert the kinetic energy into electric energy to charge the battery 13.

  In the case of a vehicle, when an ignition switch or an accessory (ACC) switch is turned on, a battery discharge current flows along with power supply to a load that is on at that time. Further, the motor generator 5 is used as a starter motor that forcibly rotates the flywheel of the engine 3 when the engine 3 is started when a starter switch (not shown) is turned on. A large inrush current flows. When the engine 3 is started by the motor generator 5 by turning on the starter switch, the starter switch is turned off and the ignition switch is turned on with the release of the operation of the ignition key (not shown). Along with this, the discharge current flowing from the battery 13 shifts to a steady current according to the load.

  Returning to the description of the configuration, the apparatus 1 of the present embodiment includes a motor generator 5 that functions as a discharge current I of a battery 13 for an electrical component such as a motor for assist driving and a motor generator 5 that functions as a starter motor, and a generator. 5 includes a current sensor 15 that detects a charging current for the battery 13 from 5 and a voltage sensor 17 that has a resistance value of about 1 M ohm connected in parallel to the battery 13 and detects a terminal voltage V of the battery 13.

  In addition, the apparatus 1 of the present embodiment includes a microcomputer (hereinafter referred to as the microcomputer) in which the outputs of the current sensor 15 and the voltage sensor 17 described above are taken in after the A / D conversion in the interface circuit (hereinafter abbreviated as “I / F”) 21. , Abbreviated as “microcomputer”).

  The microcomputer 23 includes a CPU 23a, a RAM 23b, and a ROM 23c. Among these, the CPU 23a is connected to the I / F 21 in addition to the RAM 23b and the ROM 23c. A switch, an ignition switch, an accessory switch, a switch of an electrical component (load) other than the motor generator 5 are further connected.

  The RAM 23b has a data area for storing various data and a work area used for various processing operations, and the ROM 23c stores a control program for causing the CPU 23a to perform various processing operations.

  Note that the current values and voltage values that are the outputs of the current sensor 15 and the voltage sensor 17 described above are sampled at high speed in a short cycle, and are taken into the CPU 23a of the microcomputer 23 via the I / F 21. The voltage value is used for various processes.

  Next, processing performed by the CPU 23a according to the control program stored in the ROM 23c will be described with reference to the flowchart of FIG.

  When the ignition (IG) switch is turned on to receive power from the battery 13 and the microcomputer 23 is activated to start the program, the CPU 23a starts sampling the discharge current and terminal voltage at a relatively long sampling period (step S1). Executes a process of reading measurement data via the I / F 21 by making a pair of A / D conversion values of the discharge current I of the battery 13 detected by the current sensor 15 and the terminal voltage V of the battery 13 detected by the voltage sensor 17. Then, it is monitored that the discharge current exceeds a predetermined value. When the discharge current exceeds a predetermined value, it is determined that an inrush current has started to flow, and the sampling period is switched to a short period of, for example, 100 μsec, and processing for obtaining an approximate expression is entered (step S2). This is performed during the process for obtaining an approximate expression for detecting the maximum current (peak current) of the discharge current.

  Note that the least square method is used to calculate the approximate expression. Based on the sampled discharge current and terminal voltage, each Σ term is calculated to determine the approximate expression when the current increases, and the sampling values are continuous. When the current decreases n times, it is determined that the discharge current has started to decrease from the peak value. Thereafter, each of the approximate current equations for decreasing the current is calculated based on the sampled discharge current and the terminal voltage. Calculates the Σ term. Thereafter, it is monitored whether or not the discharge current decreases beyond a predetermined value, and when the discharge current decreases beyond a predetermined value, it is determined that the inrush current has ended, and a process for obtaining an approximate expression (Step S3), the approximate expression at the time of current increase is calculated using each Σ term at the calculated current increase, and the approximate expression at the time of current decrease is calculated by using each Σ term at the calculated current decrease ( Step S4).

  Although not clearly shown in the flowchart of FIG. 6, it is naturally necessary to determine whether or not the obtained approximate expression is valid. This determination determines each coefficient of the approximate expression. Therefore, the correlation coefficient between the current increase and the current decrease that can be obtained using the calculation result of each Σ term and the magnitude of the peak current can be compared with a predetermined value. In particular, an error factor can be removed by providing two predetermined values.

  An arithmetic process for obtaining the pure resistance of the battery from the quadratic approximate expression obtained as described above is executed (step S5). In this calculation process, when the voltage drop due to the concentration polarization component is included in the quadratic expression, a corrected quadratic approximate expression calculation process for obtaining a corrected quadratic approximate expression excluding the concentration polarization voltage drop is performed. An arithmetic process for obtaining the pure resistance of the battery is executed using a quadratic approximation, and in this case, two modified quadratic approximations of the current-voltage characteristics for increasing discharge current and decreasing discharge current. After calculating the differential value at the peak value of the equation, an operation is performed to obtain an intermediate value between the two differential values as the pure resistance of the battery. The obtained pure resistance of the battery is stored and stored in the data area of the RAM 23b for use for various purposes.

  There are two methods for obtaining an intermediate value of the differential value depending on how the inrush current flows. When the time of the inrush current increasing direction and the time of decreasing direction are substantially equal, an operation is performed to obtain the addition average value of the two differential values as the pure resistance Rj.

  On the other hand, when the time in the increase direction and the time in the decrease direction of the inrush current are greatly different, the discharge current of the discharge current is changed to the differential value at the peak value of the modified quadratic approximate expression of the current-voltage characteristic for the increasing discharge current. Multiplying the ratio of the increasing discharge current flow time to the total time and the differential value at the peak value of the two modified quadratic approximations of the current-voltage characteristics for the decreasing discharge current, the total discharge current An operation is performed to obtain an added value obtained by adding the product of the ratio of the time during which the decreasing discharge current flows in the time as the pure resistance. Regardless of which method is used to determine the pure resistance, the pure resistance Rj of the battery is obtained as an intermediate value between the two differential values.

  In the above-described example, the first and second approximate expressions are both quadratic approximate expressions. However, when the first approximate expression is the primary approximate expression, the process for obtaining the corrected approximate expression is naturally unnecessary. . In this case, the slope of the linear expression is used instead of the differential value.

Next, the voltage drop Rj × I due to the pure resistance is deleted from the approximate expression at the time of current increase calculated in step S4, and the approximate expression of the voltage drop due to factors other than the pure resistance at the time of current increase, that is, when the current increases A polarization approximation formula (V = aI ² + bI + c) is obtained, and the voltage drop amount at the maximum point of the obtained polarization approximation formula is obtained as a saturation polarization voltage drop Vpip at the maximum current Ip (step S6).

  The maximum voltage drop Vmax = Rj × I0 + Vpip / Ipol · I0 generated inside the battery when discharging with a small current I0 is continued, and using the above formulas (7) and (8), The dischargeable capacity ADCi0 is calculated (step S7). Next, if the dischargeable capacity ADCi0 calculated in step S7 is 0 or less (N in step S8), the dischargeable capacity for an arbitrary discharge current I is set to 0 (step S9), and the process ends. On the other hand, if the dischargeable capacity ADCi0 calculated in step S7 is larger than 0 (Y in step S8), the small current I0 is set as the discharge current I1, and the dischargeable capacity ADCi0 is stored in the RAM 23b as the dischargeable capacity X1. (Step S10), the process proceeds to the next.

  Next, the maximum total voltage drop Vmax = Rj × Ip + Vpip generated inside the battery when discharging at the maximum current Ip is continued, and using the above formulas (7) and (8), The dischargeable capacity ADCip is calculated (step S11). Next, if the dischargeable capacity ADCip calculated in step S11 is larger than 0 (Y in step S12), the maximum current Ip is set as the discharge current I2, and the dischargeable capacity ADCip is stored in the RAM 23b as the dischargeable capacity X2. (Step S13), the process proceeds to the next Step S14.

  On the other hand, if the dischargeable capacity ADCip calculated in step S11 is 0 or less (N in step S12), the discharge current Iα at which the dischargeable capacity = 0 is calculated using the above formula (9) (step S12). In step S15, the calculated discharge current Iα is set as the discharge current I2, and the positive value Xα close to 0 is stored in the RAM 23b as the dischargeable capacity X2 (step S16), and the process proceeds to the next step S14.

  Next, the two discharge currents I1 and I2 obtained in step S15 or S16 and step S13 and the discharge durations t1 and t2 obtained by dividing the dischargeable capacities X1 and X2 by the two discharge currents I1 and I2 are expressed by the formula ( Substituting into 3) and (4) or (5) and (6) to determine the unknown constants n and C, the approximate expression represented by the Pojkert equation is determined (step S14). Thereafter, the discharge duration t for the arbitrary discharge current I is obtained using the Pokert's equation determined in step S14, and the product of the arbitrary discharge current I and the discharge duration t can be discharged for the arbitrary discharge current I. It calculates as a capacity | capacitance (step S17) and complete | finishes a process.

  However, when the dischargeable capacity ADCip is 0 or less and the process proceeds to step S17 via steps S15 and S16, in this step S17, the CPU 23a determines that the desired discharge current I is greater than or equal to the discharge current Iα. The dischargeable capacity is estimated to be 0 without using the Pojkert equation. On the other hand, when the arbitrary discharge current I to be obtained is smaller than the discharge current Iα, the dischargeable capacity is calculated as described above using the Poikert equation. As is clear from the above operation, the CPU 23a corresponds to the specific discharge duration estimation means, the approximate expression calculation means, and the dischargeable capacity estimation means in the claims.

  According to the dischargeable capacity estimation device described above, of the two data pairs (Ip, tp) and (I0, t0), there is only one data pair (I0, t0) whose discharge duration is greater than zero. However, instead of a data pair having a discharge duration of 0 or less (Ip, tp ≦ 0), a data pair comprising a discharge current Iα having a discharge duration of 0 and a predetermined positive discharge duration (Xα / Iα) ( (Αα, Xα / Iα) can be used to obtain an approximate expression represented by a Pojkert equation. As a result, the unknown constants n and C in the Pojkert equation can be determined, and the dischargeable capacity for an arbitrary discharge current I can be estimated.

  Further, according to the above-described dischargeable capacity estimation device, when the battery dischargeable capacity ADCi0 with respect to the small current I0 is 0 or less (that is, the discharge duration corresponding to the small current I0 is 0 or less), in other words, all When the discharge duration of the data pair is 0 or less, the dischargeable capacity corresponding to an arbitrary discharge current I is estimated to be 0. Thereby, it is possible to estimate an accurate dischargeable capacity without determining the unknown constants n and C.

  Furthermore, according to the dischargeable capacity estimation device described above, when the arbitrary discharge current I is smaller than the discharge current Iα, the discharge current I is set to the arbitrary discharge current I using the Pokert's equation in which the constants n and C are determined in step S14. The dischargeable capacity of the corresponding battery is estimated. When the arbitrary discharge current I is equal to or greater than the discharge current Iα, the dischargeable capacity corresponding to the arbitrary discharge current I is estimated to be zero. Accordingly, it is possible to estimate an accurate dischargeable capacity corresponding to the magnitude of an arbitrary discharge current.

  In the embodiment described above, a positive value Xα corresponding to the dischargeable capacity is determined in advance, and a value Xα / Iα obtained by dividing the positive value Xα by the discharge current Iα when the discharge current is 0 is a predetermined positive discharge duration. Then, instead of the data pair (Ip, tp ≦ 0), the Poikert equation is obtained using the data pair (Iα, Xα / Iα). However, the positive discharge duration tα may be determined in advance, and the Pokert equation may be obtained using the data pair (Iα, tα) instead of the data pair (Ip, tp ≦ 0).

  Further, in the above-described embodiment, when the dischargeable capacity ADCip corresponding to the maximum current Ip is 0 or less, the constant n in the Pokert's equation using (Iα, Xα / Iα) instead of (Ip, tp). , C was determined. As described above, Iα is a discharge current when the dischargeable capacity is 0, Xα is a predetermined positive dischargeable capacity, I0 is a small current, and ADCi0 is a dischargeable capacity corresponding to the small current I0. However, as shown in FIG. 7, for example, when tp is 0 or a negative value that is as close to 0 as possible, (Ip, tα (predetermined positive discharge duration) is used instead of (Ip, tp). It is possible to determine the Poikert equation by substituting it, but when ADCip is a negative value and large to some extent, it is more accurate to substitute (Iα, Xα / Iα) as in the above-described embodiment. Can be requested.

  In FIG. 7, a curve L22 is a curve representing a Pojkert equation obtained from a data pair (I0, t0), (Ip, tα). As shown in the figure, also in this case, as the value of tα is closer to 0, the curve L22 is closer to the curve L1, and can be approximated with a Pokert equation with high accuracy. In addition, when the Pokert's equation is obtained using the data pair (Ip, tα) instead of the data pair (Ip, tp) as described above, if tp ≦ 0, the above equation (9) is used. It is conceivable that the discharge current Iα at which the dischargeable capacity = 0 is obtained, and when the obtained arbitrary discharge current I is equal to or greater than the discharge current Iα, the dischargeable capacity 0 is estimated without using the Pokert equation.

  Further, in the above-described embodiment, the discharge current Iα at which the dischargeable capacity becomes zero is estimated using the equation (9). However, the method for estimating the discharge current Iα is not limited to the above-described embodiment. For example, it is noted that the difference between the maximum current Ip and the discharge current Iα increases as the absolute value of the negative ADCip increases. Thus, it is conceivable to estimate the discharge current Iα.

Second Embodiment In the above-described embodiment, the method for obtaining the Pokert equation when the relationship between the two currents Ip, I0 and the discharge durations tp, t0 with respect to the two currents Ip, I0 has been described. However, the relationship between three or more currents I1 ... Im and the discharge duration t1 ... tm corresponding to the three or more currents is clear in advance, and three or more data pairs (I1, t1) ... (Im, tm) (However, when I1 <I2... <Im), the Pokert's equation may be obtained by the following method.

  The operation of the dischargeable capacity estimation device in the second embodiment will be described below with reference to the flowchart showing the processing procedure of the CPU 23a shown in FIG. First, the CPU 23a resets the count value n (step S20). Next, it is determined whether or not the discharge duration tn is 0 or less (step S21). If the discharge duration tn is greater than 0 (N in step S21), it is determined whether the count value n has reached the total data logarithm m (step S22). If the count value n has not reached the total data logarithm m (N in step S22), the count value n is incremented (step S23), and the process returns to step S21 again.

  On the other hand, if the count value n has reached the total data logarithm m (Y in step S22), the discharge durations constituting the data pairs (I1, t1)... (Im, tm) are all greater than zero. Judgment is made (∵t1>...> Tm> 0), and these data pairs (I1, t1)... (Im, tm) are substituted into equations (5) and (6) to obtain a Pokert equation (step S24).

  If the discharge duration tn is 0 or less (Y in step S21), it is determined whether or not the count value n is 1 (step S25). If the count value n is greater than 1 (N in step S25), the discharge current Iα at which the dischargeable capacity = 0 is calculated using the above equation (9) (step S26), and the discharge duration is 0 or less. Instead of the pair (In, tn)... (Im, tm), the Pokert's equation is obtained using the data pair (Iα, tα (= predetermined positive discharge duration)) (step S27). Specifically, the Pokert equation is obtained by substituting the data pair (I1, t1)... (In + 1, tn + 1) and the data pair (Iα, tα) into the equations (5) and (6). Ask for.

  Thereafter, the discharge duration t for an arbitrary discharge current I is obtained using the Pokert's equation determined in step S24 or S27, and the product of the arbitrary discharge current I and the discharge duration t is calculated for the arbitrary discharge current I. The dischargeable capacity is calculated (step S28), and the process ends. However, if there is a data pair having a dischargeable capacity of 0 or less and the process proceeds to step S28 via step S27, the CPU 23a determines that the desired discharge current I is greater than or equal to the discharge current Iα in step S28. The dischargeable capacity is estimated as 0 without using the Pokert equation. On the other hand, when the arbitrary discharge current I to be obtained is smaller than the discharge current Iα, the dischargeable capacity is calculated as described above using the Poikert equation.

  On the other hand, if the count value n is 1 (Y in step S25), it is determined that the discharge durations constituting the data pair (I1, t1)... (Im, tm) are all 0 or less (∵0> t1). > ...> tm), and the dischargeable capacity is set to 0 (step S29).

  According to the dischargeable capacity calculation device described above, when there is at least one data pair having a discharge duration of 0 or less, the discharge current Iα is estimated such that the discharge duration is 0, and the discharge duration is 0 or less. Instead of the pair (In, tn)... (Im, tm), a pokert using a data pair (Iα, tα) composed of a discharge current Iα with an estimated discharge duration of zero and a predetermined positive discharge duration tα The approximate expression expressed by the following formula was obtained. Thus, when there is only one data pair (I1, t1) with a discharge duration greater than 0, of course, instead of a data pair (In, tn) ... (Im, tm) with a discharge duration of 0 or less, Using the data pair (Iα, tα), a Pojkert equation can be obtained.

  In the second embodiment described above, the constants n and C in the Pokert's equation are determined using (Iα, tα) instead of the data pair having the discharge duration of 0 or less. However, for example, when the maximum discharge duration tn of the data pair (In, tn)... (Im, tm) having a discharge duration of 0 or less is 0 or a negative value close to 0, the discharge duration Using a data pair (In, tα) consisting of a minimum discharge current In and a predetermined positive discharge duration tα among the discharge currents constituting a data pair (In, tn) (Im, tm) of which is less than or equal to 0 The Pokert equation may be determined. Of course, in this case as well, tα can be approximated with a Pokert equation with higher accuracy as the value is closer to zero.

  Also, when the Pokert's equation is obtained using the data pair (In, tα) instead of the data pair (In, tn)... (Im, tm) as described above, If there is at least one, the discharge current Iα at which dischargeable capacity = 0 is obtained using the above equation (9), and if the obtained arbitrary discharge current I is equal to or greater than the discharge current Iα, the Pokert equation is not used. It can be estimated that the dischargeable capacity is zero.

  In the second embodiment described above, when there is at least one data pair with a discharge duration of 0 or less, instead of a data pair with a discharge duration of 0 or less, (Iα, tα) and (In, tα) Was used to find the Pojkert equation. In other words, both when there is only one data pair with a discharge duration greater than 0, and when there are two or more data pairs with a discharge duration greater than 0 and at least one data pair with a duration less than 0. In addition, the Pokert's equation was obtained using (Iα, tα) or (In, tα) instead of a data pair having a discharge duration of 0 or less.

  However, the present invention is not limited to this. When there is at least one data pair having a discharge duration greater than 0, a data pair (Iα, Any method may be used as long as it can obtain a Pokert equation using (tα) and (In, tα). Therefore, for example, even if there is a data pair having a discharge duration of 0 or less, if there are two or more data pairs having a discharge duration of greater than 0, two or more data pairs having a discharge duration of greater than 0 are used. The Pokert equation may be obtained using (Iα, tα) or (In, tα) only when there is only one data pair having a discharge duration greater than zero.

  If there are two or more data pairs with a discharge duration of 0 or less and there are two or more data pairs with a discharge duration of greater than 0, then using two or more data pairs with a discharge duration of greater than 0, the Pokert's The formula can be obtained. However, when there is at least one data pair with a discharge duration of 0 or less as in the second embodiment described above, instead of a data pair with a discharge duration of 0 or less, (Iα, tα) and (In, tα ) Can be used to calculate the Pokert's equation, compared to the case where (Iα, tα) or (In, tα) is not used, and the logarithm of data can be increased more accurately. Can be sought.

Third Embodiment Next, a dischargeable capacity estimation apparatus according to a third embodiment will be described. Since the configuration of the dischargeable capacity estimation device in the third embodiment is the same as that in the first and second embodiments described above, detailed description thereof is omitted. First, the operation of the dischargeable capacity estimation apparatus in the third embodiment will be described with reference to the flowchart of FIG.

  The CPU 23a functions as specific dischargeable capacity estimation means, obtains the dischargeable capacity ADCip and ADCi0 corresponding to the maximum current Ip and the small current I0 as described above, and sets the dischargeable capacity data pairs (Ip, ADCip), (Ip, ADCi0) is obtained (step S30). If both dischargeable capacities ADCip and ADCi0 are greater than 0 (Y in steps S31 and S32), the discharge duration data pair (I0, t0 (=) is calculated from the dischargeable capacity data pair (I0, ADCi0), (Ip, ADCi0)). ADCi0 / I0)), (Ip, tp (= ADCip / Ip)), and the obtained discharge duration data pair (I0, t0), (Ip, tp) is expressed by equations (3) and (4) or (5). ) And (6) to determine the Pokert's equation (step S33).

Next, the discharge duration t (= C / I ⁿ ) for an arbitrary discharge current I is obtained using the Pokert formula determined in step S33, and the arbitrary discharge current I and the discharge duration t (= C / I) are obtained. ⁿ )) (C / I ⁿ ) · I is calculated as a dischargeable capacity ADC for an arbitrary discharge current I (step S34), and the process ends.

  On the other hand, if dischargeable capacity ADCip is 0 or less and dischargeable capacity ADCi0 is larger than 0 (Y in step S31, N in S32), first, the capacity between predetermined positive dischargeable capacity Xα and dischargeable capacity ADCip The difference β1 (= Xα−ADCip) is obtained (step S35).

  Then, the capacity difference β1 is added to each of the dischargeable capacity ADCi0 and ADCip constituting the dischargeable capacity data pair (I0, ADCi0) and (Ip, ADCip), and the additional dischargeable capacity data pair (I0, ADCi0 + β1), ( Ip, ADCip + β1) is obtained, and an additional discharge duration data pair (I0, (ADCi0 + β) / I0), (Ip, (ADCip + β) / Ip) is obtained from the obtained additional dischargeable capacity data pair. Since ADCi0 / I0 = t0 and ADCip / Ip = tp, the additional discharge duration data pair (I0, t0 + β / I0) and (Ip, tp + β / Ip) can be rewritten. Since β is Xα (> 0) −ADCip (<0), the discharge durations t0 + β / I0 and tp + β / Ip constituting the added discharge duration data pair are both greater than zero.

Then, the obtained addition discharge duration data pair (I0, t0 + β / I0), (Ip, tp + β / Ip) is substituted into the equations (3) and (4) or (5) and (6), and the Pokert equation Is determined (step S36). By substituting any of the discharge current I in the formula I ⁿ · t = C of Poikeruto determined in this step S36, the discharge current obtains a discharge duration t (= C / I ⁿ⁾ for I, obtained discharge duration t When the relationship between the dischargeable capacity I · t multiplied by the discharge current I and the discharge current I is plotted, a curve L4 shown in FIG. 10 is obtained. L3 is a curve showing the relationship between the actual discharge current and the dischargeable capacity.

As is clear from FIG. 10, the curve L4 shows the relationship between the discharge current I and the capacity obtained by adding the capacity difference β1 to the actual dischargeable capacity. Therefore, when obtaining the dischargeable capacity, by substituting any of the discharge current I in equation Poikeruto determined in step S36, obtains a discharge duration t = C / I ^n, obtained discharge duration t = C / I ^The dischargeable capacity (C / I ⁿ ) · I is obtained by multiplying ⁿ by the discharge current I. Since the obtained dischargeable capacity (C / I ⁿ ) · I is a value obtained by adding β1, a value obtained by subtracting the difference β1 from the obtained dischargeable capacity (C / I ⁿ ) · I (C / I ⁿ ) Obtain I-β1 as a dischargeable capacity (step S37) and end the process.

  On the other hand, when both the dischargeable capacities ADCi0 and ADCip are 0 or less (N in step S31), the CPU 23a sets the dischargeable capacity for an arbitrary discharge current I to 0 (step S38) and ends the process. .

Fourth Embodiment In the third embodiment described above, the method for obtaining the Pokert equation when the relationship between the two currents Ip, I0 and the discharge durations tp, t0 with respect to the two currents Ip, I0 is explained. It was. However, the relationship between the three or more currents I1... Im and the dischargeable capacity X1... Xm corresponding to the three or more currents is clear in advance, and three or more dischargeable capacity data pairs (I1, X1). , Xm) (where I1 <I2... Im), the third embodiment may be applied as follows.

  Among the three or more data pairs (I1, X1) (Im, Xm), the data pair (I1, X1) (In-1, Xn-1) is a data pair having a dischargeable capacity greater than zero. Yes (∵X1>...> Xn-1> 0), data pair (In, Xn)... (Im, Xm) is a data pair having a dischargeable capacity of 0 or less (∵0> Xn>...> Xm). At this time, for example, a predetermined positive dischargeable capacity Xα and a dischargeable capacity Xk (n ≦ k ≦ m) of any one of zero or less dischargeable capacity Xn... Xm constituting the dischargeable capacity data pair. The difference β1 (= Xα−Xk) is obtained (n, m, and k are integers).

  Next, an additional dischargeable capacity data pair (I1, X1 + β1) (Im) obtained by adding a capacity difference β1 (= tα−tk) to each of the dischargeable capacity X1... Xm constituting a plurality of dischargeable capacity data pairs. , Xm + β1), an additional dischargeable capacity data pair (I1, X1 + β1) (Ik, Xk + β1 (= Xα)) having a dischargeable capacity larger than 0 is obtained. Dischargeable capacity data pair (I1) obtained by adding capacity difference β1 (= Xα−Xk) to dischargeable capacity data pair (I1, X1)... (Ik, Xk) composed of dischargeable capacity of Xk or more. , X1 + β1) (Ik, Xk + β1), the dischargeable capacity X1 + β1... Xk + β1 is larger than 0.

  Then, from this additional dischargeable capacity data pair (I1, X1 + β1) (Ik, Xk + β1) where the dischargeable capacity is greater than 0, the additional discharge duration data pair (I1, t1 + β1 / I1) (Ik, tk + β / Ik) ) Naturally, the discharge durations t1 + β1 / I1... Tk + β1 / Ik constituting the additional discharge duration data pair are all values larger than 0, and using this discharge duration data, the addition approximate expression expressed by the Pokert equation is used. Ask.

When the dischargeable capacity is obtained from the Pokert equation thus obtained, as in the third embodiment, an arbitrary discharge current I is substituted into the Pokert equation and the discharge duration t = C / I. seek ^n, obtains a value obtained by subtracting the capacity difference β1 from a value multiplied by the discharge duration t = C / I ⁿ determined with the discharge current I as a discharge capacity.

  According to the dischargeable capacity estimation device described above, when there is at least one discharge duration data pair whose discharge duration is 0 or less, the discharge duration data pair (I1, t1 + β1 / I1) obtained by adding the capacities as described above. It is conceivable to calculate a Pojkert equation using (Ik, tk + β1 / Ik). As a result, when only one discharge duration data pair (I1, t1) having a discharge duration greater than 0 is obtained, two or more discharges having a discharge duration greater than 0 obtained by adding the capacities are obtained. It is possible to obtain a Pokert's equation using the duration data pairs (I1, t1 + β1 / I1)... (Ik, tk + β1 / Ik).

  Therefore, even when there is only one discharge duration data pair having a discharge duration greater than 0, by adding the capacity, a discharge duration data pair (I1, t1 + β1 / I1) having a discharge duration greater than 0 is obtained. ... (Ik, tk + β / Ik) can be obtained two or more. For this reason, it is possible to obtain an approximate expression approximated by a Poikert equation using at least two or more additional discharge duration data pairs greater than zero.

  Also in this case, if there is at least one data pair whose discharge duration is 0 or less, the discharge current Iα at which the dischargeable capacity = 0 is obtained using the above formula (9), and the obtained arbitrary discharge current When I is equal to or greater than the discharge current Iα, it can be estimated that the dischargeable capacity is zero without using the Pokert equation.

  In the fourth embodiment described above, when there is at least one discharge duration data pair with a discharge duration of 0 or less, the added discharge duration data pair (I1, t1 + β1 / I1) obtained by adding the capacities ... The Pojkert equation was calculated using (Ik, tk + β1 / Ik). In other words, both when there is only one data pair with a discharge duration greater than 0, and when there are two or more data pairs with a discharge duration greater than 0 and at least one data pair with a duration less than 0. Then, the Pokert's equation was obtained using the added discharge duration data pair (I1, t1 + β1 / I1) (Ik, tk + β1 / Ik) obtained by adding the capacities.

  However, the present invention is not limited to this, and when there is only one discharge duration data pair having at least a discharge duration greater than 0, the added discharge duration data pair obtained by adding the capacity or adding the time. (I1, t1 + β1 / I1)... (Ik, tk + β1 / Ik) may be used. Therefore, for example, even if there is a discharge duration data pair having a discharge duration of 0 or less, if at least two discharge duration data pairs having a discharge duration of greater than 0 are obtained, the discharge duration is greater than 0. A Pokert's equation is obtained using two or more discharge duration data pairs, and only when a single data pair having a discharge duration greater than 0 is obtained, the added discharge duration data pair ( Poikert's equation may be obtained using I1, t1 + β1 / I1) (Ik, Xk + β1 / Ik).

  If there are two or more data pairs with a discharge duration of 0 or less and there are two or more data pairs with a discharge duration of greater than 0, then using two or more data pairs with a discharge duration of greater than 0, the Pokert's The formula can be obtained. However, when there is at least one data pair whose discharge duration is 0 or less as in the fourth embodiment described above, the method of obtaining the Pokert's equation using the additional discharge duration data pair is compared with the case where it is not used. Thus, it is possible to increase the logarithm of at least one or more data, and to obtain a Pokert equation that is more accurately approximated.

It is a graph which shows the change of the discharge current at the time of high rate discharge, and a battery terminal voltage. It is a graph for demonstrating the method of estimation of a saturation polarization voltage drop. It is a graph used in order to compare the determined relational expression and an actual measurement curve while explaining the method of determining Poikert's expression to the relational expression of a specific battery. It is a graph which shows the relationship between discharge duration and discharge current. It is a block diagram which shows the basic block diagram of the dischargeable capacity estimation apparatus of the battery of this invention. It is a flowchart which shows the process sequence of CPU23a in 1st Embodiment. It is a graph which shows the relationship between discharge duration and discharge current. It is a flowchart which shows the process sequence of CPU23a in 2nd Embodiment. It is a flowchart which shows the process sequence of CPU23a in 3rd Embodiment. It is a graph which shows the relationship between dischargeable capacity and discharge current. It is a graph which shows the relationship between the arbitrary discharge current I of a battery, and the discharge duration t which can maintain the said discharge current I. It is a graph which shows the relationship between the arbitrary discharge current I of the battery for explaining the conventional problem, and the discharge duration t which can sustain the said discharge current I.

Explanation of symbols

n constant (first constant)
C constant (second constant)
23a CPU (specific discharge duration estimation means, specific dischargeable capacity estimation means, constant determination means, dischargeable capacity estimation means)

Claims (9)

The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. An apparatus for obtaining an approximate expression approximated by the relational expression shown,
Specific discharge duration estimation means for estimating a discharge duration corresponding to each of a plurality of discharge currents of a specific magnitude based on the discharge current and the terminal voltage measured during the discharge of the battery;
An approximate expression calculating means for obtaining an approximate expression obtained by approximating a plurality of data pairs including the discharge current having the specific magnitude and the estimated discharge duration corresponding to the discharge current having the specific magnitude by the relational expression; With
When there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, the approximate expression calculating unit is configured to replace the discharge duration with a duration of 0 instead of the data pair with the discharge duration of 0 or less. An approximate expression calculation apparatus, wherein the approximate expression is obtained using a data pair including a minimum discharge current and a predetermined positive discharge duration among discharge currents constituting the following data pairs. The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. An apparatus for obtaining an approximate expression approximated by the relational expression shown,
Specific discharge duration estimation means for estimating a discharge duration corresponding to each of a plurality of discharge currents of a specific magnitude based on the discharge current and the terminal voltage measured during the discharge of the battery;
Approximate expression calculating means for obtaining the approximate expression by approximating a plurality of data pairs composed of the discharge current of the specific magnitude and the estimated discharge duration corresponding to the discharge current of the specific magnitude with a functional expression. And
The approximate expression calculating means estimates a discharge current at which the discharge duration is zero when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, and the discharge duration is zero. Instead of the following data pair, the approximate expression calculation apparatus is characterized in that the approximate expression is obtained using a data pair consisting of a discharge current at which the estimated discharge duration is zero and a predetermined positive discharge duration. The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. An apparatus for obtaining an approximate expression approximated by the relational expression shown,
Based on the discharge current and terminal voltage measured during the discharge of the battery, the dischargeable capacity corresponding to each of a plurality of discharge currents of a specific magnitude is estimated, and the discharge current of the specific magnitude and the discharge current are supported. Specific dischargeable capacity estimation means for obtaining a plurality of dischargeable capacity data pairs composed of the dischargeable capacity estimated
A discharge comprising a discharge current having a specific magnitude and a discharge duration obtained by dividing the estimated dischargeable capacity corresponding to the discharge current by the discharge current from the plurality of dischargeable capacity data pairs. An approximate expression calculating means for obtaining a duration data pair, and obtaining the approximate expression obtained by approximating the obtained discharge duration data pair with the functional expression;
The approximate expression calculating means, when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, a predetermined positive dischargeable capacity and a dischargeable capacity constituting the dischargeable capacity data pair A plurality of capacitance differences obtained by adding the capacitance difference to each of the dischargeable capacities constituting the plurality of dischargeable capacity data pairs instead of the plurality of dischargeable capacity data pairs. An approximate expression calculation apparatus that obtains the discharge duration data pair from an additional dischargeable capacity data pair in which the dischargeable capacity is greater than 0 among the additional dischargeable capacity data pairs. The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. A method for obtaining an approximate expression approximated by a relational expression shown in FIG.
Based on the discharge current and terminal voltage measured during the discharge of the battery, estimate the discharge duration corresponding to each of a plurality of discharge currents of a specific magnitude,
An approximate expression is obtained by approximating the plurality of data pairs composed of the estimated discharge duration corresponding to the discharge current of the specific magnitude and the discharge current of the specific magnitude by the relational expression,
When there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, a data pair having the discharge duration of 0 or less is configured instead of the data pair having a discharge duration of 0 or less. An approximate expression calculation method characterized in that the approximate expression is obtained using a data pair consisting of a minimum discharge current and a predetermined positive discharge duration of the discharge current. The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. A method for obtaining an approximate expression approximated by a relational expression shown in FIG.
Based on the discharge current and terminal voltage measured during the discharge of the battery, estimate the discharge duration corresponding to each of a plurality of discharge currents of a specific magnitude,
By approximating a plurality of data pairs consisting of the estimated discharge duration and the estimated discharge duration corresponding to the specific magnitude of the discharge current and the specific magnitude of the discharge current, the approximate expression is obtained,
When there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs, a discharge current at which the discharge duration is 0 is estimated, and instead of the data pair having the discharge duration of 0 or less A method of calculating an approximate expression, wherein the approximate expression is obtained using a data pair consisting of a discharge current at which the estimated discharge duration is zero and a predetermined positive discharge duration. The relationship between the discharge current of the battery and the discharge duration during which the discharge current can be continuously discharged is determined by the product of the first constant power of the discharge current and the discharge duration being a second constant. A method for obtaining an approximate expression approximated by a relational expression shown in FIG.
Based on the discharge current and terminal voltage measured during the discharge of the battery, the dischargeable capacity corresponding to each of a plurality of discharge currents of a specific magnitude is estimated, and the discharge current of the specific magnitude and the discharge current are supported. To obtain a plurality of dischargeable capacity data pairs comprising the estimated dischargeable capacity,
A discharge comprising a discharge current having a specific magnitude and a discharge duration obtained by dividing the estimated dischargeable capacity corresponding to the discharge current by the discharge current from the plurality of dischargeable capacity data pairs. Obtaining a duration data pair, obtaining the approximate expression obtained by approximating the obtained discharge duration data pair with the functional expression,
A capacity of a predetermined positive dischargeable capacity and any one of the dischargeable capacity constituting the dischargeable capacity data pair when there is at least one data pair having a discharge duration of 0 or less among the plurality of data pairs A plurality of additional dischargeable capacity data pairs obtained by obtaining the difference and adding the capacity difference to each of the dischargeable capacities constituting the plurality of dischargeable capacity data pairs instead of the plurality of dischargeable capacity data pairs. Wherein the discharge duration data pair is obtained from an additional dischargeable capacity data pair in which the dischargeable capacity is greater than zero. The approximate expression calculation apparatus according to claim 1, 2, or 3,
Using the approximate expression calculated by the approximate expression calculating means, a discharge duration for an arbitrary discharge current is obtained, and the battery can be discharged from a value obtained by multiplying the arbitrary discharge current and the obtained discharge duration. A dischargeable capacity estimation device comprising: a dischargeable capacity estimation means for estimating a correct capacity. The dischargeable capacity estimation device according to claim 7,
The dischargeable capacity estimation means estimates that the dischargeable capacity corresponding to an arbitrary discharge current is zero when the discharge durations for the plurality of discharge currents estimated by the specific discharge duration estimation means are all 0 or less. A dischargeable capacity estimation device characterized by the above. The dischargeable capacity estimation device according to claim 7 or 8,
The dischargeable capacity estimation means estimates a discharge current at which the discharge duration becomes 0 when there is at least one data having a discharge duration of 0 or less among the plurality of data pairs, and the arbitrary discharge A dischargeable capacity estimation device, wherein when a current is equal to or greater than a discharge current at which the estimated discharge duration is zero, a dischargeable capacity corresponding to the arbitrary discharge current is estimated as zero.

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