JP2007108063A - Method and device for determining secondary battery degradation, and power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery degradation state determining method or the like capable of determining the secondary battery degradation state at a high accuracy by appropriately correcting the variation of internal impedance or internal resistance by used temperature of the secondary battery. <P>SOLUTION: The temperature characteristic function used by the secondary battery degradation determining method includes at least one or more exponent items and one adjusting parameter. An example (graph 2) where only one exponent item is included in the temperature characteristic function of the internal impedance is shown together with a measured value (graph 1), and they are sufficiently matched with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field such as a secondary battery deterioration state determination method for determining a deterioration state of a secondary battery that supplies power to a load, and in particular, estimates an internal impedance or internal resistance of a secondary battery, and an estimation result thereof The present invention relates to a technical field such as a secondary battery deterioration determination method for determining a deterioration state of a secondary battery based on the above.

  For secondary batteries such as lead-acid batteries mounted on automobiles and the like, a technique for determining the deterioration state has been conventionally known. For example, there is an example described in Patent Document 1.

  Generally, since the internal impedance or internal resistance of a secondary battery is strongly correlated with the deterioration state of the secondary battery, if the internal impedance or internal resistance of the secondary battery can be known, the deterioration of the secondary battery can be determined from the result. The degree can be determined. Thereby, it is possible to prompt the user to replace the secondary battery having a large degree of deterioration.

  In a power supply system having a secondary battery, in order to be able to determine the deterioration state of the secondary battery, the secondary battery is charged or discharged with a predetermined current, and the current and voltage at that time are measured, What is necessary is just to employ | adopt the structure which calculates internal impedance or internal resistance by predetermined calculation from the measured electric current and voltage.

  When a secondary battery is installed in an automobile, etc., it is assumed that it will be used in various regions and external environments, so it is guaranteed that the secondary battery will operate normally over a very wide range of operating temperatures. Become important.

  On the other hand, the internal impedance or internal resistance of the secondary battery varies greatly depending on the temperature, and tends to increase remarkably at low temperatures. Therefore, even if the internal impedance or the internal resistance is within an allowable range at normal temperature, the use of the secondary battery may be hindered by deviating from the allowable range at a low temperature.

  Therefore, it is important to reliably determine the deterioration state regardless of the operating temperature of the secondary battery. For that purpose, the internal impedance or internal resistance of the secondary battery is subjected to temperature correction by some method. It is necessary to estimate with. Since the internal impedance or internal resistance of a secondary battery has complex temperature characteristics, it is difficult to accurately approximate it with a simple approximation formula, etc., and temperature correction of the internal impedance or internal resistance is high. It was not easy to do with accuracy.

Therefore, Patent Document 2 discloses a conventional technique in which the deterioration state of the secondary battery is determined with high accuracy by correcting the temperature characteristics of the internal impedance using at least a third-order polynomial.
JP 2001-228226 A JP-A-2005-91217

  However, the conventional secondary battery deterioration determination method has the following problems. In order to calculate the internal impedance, the secondary battery is charged or discharged with a predetermined current and the current and voltage at that time are measured. When the predetermined current is a low-frequency alternating current of 20 Hz or less, The method according to Patent Document 2 can also determine the deterioration of the secondary battery.

  However, when the predetermined current is a low frequency alternating current of 20 Hz or less, there is a problem that noise cannot be ignored. That is, when the secondary battery is charged with the predetermined current, the alternator is used for charging. However, with a low-frequency alternating current of 20 Hz or less, noise from the alternator cannot be ignored. Further, even when the predetermined current is discharged, it is affected by noise from the load.

  Therefore, in order to avoid the influence of noise from the alternator or the load, it is necessary to use an alternating current of 100 Hz or more as the predetermined current. When a pulsed direct current is used as the predetermined current, it is necessary to use a measured current value and a measured voltage value within 10 ms after applying the pulse current for calculating the internal resistance.

  However, when a response within 10 ms with respect to an alternating current of 100 Hz or higher or a pulsed current is used as the predetermined current, the secondary battery deterioration determination method described in Patent Document 2 has a sufficient accuracy. It was not possible to judge the deterioration of.

  Accordingly, the present invention has been made to solve such a problem, and accurately corrects the change in internal impedance or internal resistance due to the operating temperature of the secondary battery, thereby accurately determining the deterioration state of the secondary battery. An object of the present invention is to provide a secondary battery deterioration state determination method that can be determined.

  A first aspect of the secondary battery deterioration determination method of the present invention is a secondary battery deterioration determination method for determining a deterioration state of the secondary battery based on an internal impedance or an internal resistance of a secondary battery that supplies power to a load. A predetermined temperature characteristic function including at least one exponential term and one adjustment parameter, representing a temperature dependence of the internal impedance or the internal resistance is created in advance, and the secondary battery has a predetermined The internal impedance or the internal resistance is calculated based on a current measurement value and a voltage measurement value when charged or discharged with current, and the second battery when the secondary battery is charged or discharged with the predetermined current is calculated. Substituting the measured temperature value of the secondary battery and the calculated internal impedance or internal resistance into the temperature characteristic function to determine the value of the adjustment parameter, the determined The reference internal impedance or reference internal resistance is calculated by substituting the value of the adjustment parameter and a predetermined reference temperature into the temperature characteristic function, and the secondary battery is deteriorated based on the calculated reference internal impedance or reference internal resistance. It is a secondary battery deterioration determination method characterized by determining a state.

（ここで、ｆ、ｇは所定の関数を表す）
と表されることを特徴とする二次電池劣化判定方法である。 In a second aspect, when the temperature characteristic function is Z, the internal impedance is R, the internal resistance is R, the adjustment parameter is C, and the temperature of the secondary battery is Temp,

(Where f and g represent predetermined functions)
This is a secondary battery deterioration determination method.

  In the third aspect, a first determination threshold value for performing deterioration determination based on the reference internal impedance and a second determination threshold value for performing deterioration determination based on the reference internal resistance are set in advance, respectively. In addition, when the reference internal impedance is calculated, the relationship between the reference internal impedance and the first determination threshold value is evaluated, and when the reference internal resistance is calculated, the reference internal impedance is calculated with the second determination threshold value. A secondary battery deterioration determination method characterized by evaluating a magnitude relationship and determining a deterioration state of the secondary battery based on any of the magnitude relationships.

  According to a fourth aspect, the internal impedance is calculated based on the measured current value and the measured voltage value when the alternating current having a frequency of 100 Hz or more is charged or discharged as the predetermined current. This is a secondary battery deterioration determination method.

  In a fifth aspect, a pulsed current is charged or discharged as the predetermined current, and the internal resistance is calculated based on the measured current value and the measured voltage value within 10 ms after the start of the charging or discharging. This is a characteristic secondary battery deterioration determination method.

  A sixth aspect is a secondary battery deterioration determination device that determines a deterioration state of the secondary battery based on an internal impedance or an internal resistance of a secondary battery that supplies power to a load. A charging circuit that charges the current of the secondary battery, a discharge circuit that discharges a predetermined current from the secondary battery, a current sensor that measures the current of the secondary battery, a voltage sensor that measures the voltage of the secondary battery, A temperature sensor that measures the temperature of the secondary battery, and a current measurement value, a voltage measurement value, and a temperature measurement value when the secondary battery is charged or discharged at a predetermined current by the charging circuit or the discharging circuit, respectively. Input from the current sensor, voltage sensor and temperature sensor, calculate the internal impedance or the internal resistance based on the current measurement value and the voltage measurement value, at least one or more The value of the adjustment parameter obtained by substituting the calculated internal impedance or internal resistance and the temperature measurement value into a temperature characteristic function including an exponential term and one adjustment parameter and representing the temperature dependence of the internal impedance or the internal resistance. And calculating a reference internal impedance or a reference internal resistance by substituting the value of the determined adjustment parameter and a predetermined reference temperature into the temperature characteristic function, and calculating the reference internal impedance or the reference internal resistance. And a control unit for determining a deterioration state of the secondary battery based on the secondary battery deterioration determination device.

  In a seventh aspect, a first determination threshold value for performing deterioration determination based on the reference internal impedance and a second determination threshold value for performing deterioration determination based on the reference internal resistance are stored in advance. And when the control means calculates the reference internal impedance, the first determination threshold value is read from the storage means, the magnitude relation with the reference internal impedance is evaluated, and the reference internal resistance is calculated. If so, the second determination threshold value is read from the storage means, the magnitude relation with the reference internal resistance is evaluated, and the deterioration state of the secondary battery is judged based on one of the magnitude relations. It is the characteristic secondary battery deterioration determination apparatus.

  In an eighth aspect, the storage means stores a charge / discharge selection signal indicating whether to charge or discharge the predetermined current to the secondary battery, and the control means receives the charge from the storage means. A secondary battery deterioration determination device that reads a discharge selection signal and outputs a predetermined command signal to either the charge circuit or the discharge circuit based on the charge / discharge selection signal.

  In a ninth aspect, the storage means stores a cross current selection signal that specifies whether the predetermined current is an alternating current having a frequency of 100 Hz or more or a pulsed current, and the control means is configured to store the current from the storage means. Read the cross current selection signal, select either an alternating current with a frequency of 100 Hz or higher or a pulsed current based on the cross current selection signal, and output a predetermined control signal to the charging circuit or the discharging circuit. This is a secondary battery deterioration determination device.

  In the tenth aspect, the storage means stores the frequency of the alternating current and / or the pulse width of the pulsed current, and the control means sends the frequency of the alternating current and / or the pulse from the storage means. The pulse width of the current is read, and the frequency of the alternating current and / or the pulse width of the pulse current is charged simultaneously with the predetermined control signal for the charging circuit or the discharging circuit or prior to the predetermined control signal. It is a secondary battery deterioration determination apparatus characterized by setting to a circuit or the said discharge circuit.

  An eleventh aspect is a power supply system including the secondary battery deterioration determination device according to any one of the sixth to tenth aspects.

  A twelfth aspect is a power supply system characterized by comprising display means for inputting and displaying a deterioration state determination result of the secondary battery from the secondary battery deterioration determination device.

  A thirteenth aspect includes input means for changing the data stored in the storage means, and the first determination threshold, the second determination threshold, the charge / discharge selection signal, the direct Any one or all of an alternating current selection signal, a frequency of the alternating current, and a pulse width of the pulsed current can be changed.

  According to the present invention, the reference internal impedance or reference at a predetermined reference temperature is corrected by correcting the temperature dependence of the internal impedance or internal resistance of the secondary battery using a temperature characteristic function including at least one exponential term. Since the internal resistance is estimated and the deterioration state of the secondary battery is determined, the deterioration state of the secondary battery can be reliably determined with high accuracy regardless of the operating temperature.

  In addition, since the adjustment parameter of the temperature characteristic function is determined based on the measured current value, the measured voltage value, and the measured temperature value of the secondary battery, the temperature characteristic change due to the aging deterioration of the secondary battery, etc. In addition, the deterioration state of the secondary battery can be accurately determined.

  Configurations of a secondary battery deterioration determination method, a secondary battery deterioration determination device, and a power supply system in a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description. Hereinafter, in the present embodiment, a case where the present invention is applied to a vehicle power supply device and a vehicle power supply system having a function of determining a deterioration state of a secondary battery mounted on a vehicle such as an automobile will be described. .

  FIG. 2 is a block diagram illustrating a schematic configuration of the vehicle power supply device according to the present embodiment. In FIG. 2, the vehicle power supply device 11 includes a secondary battery 12, a current sensor 13, a voltage sensor 14, and a temperature sensor 15 that are sensors for measuring the current, voltage, and temperature of the secondary battery 12. It has. In addition, a discharge circuit 16, a control unit 17, and a storage unit 18 are provided for determining deterioration of the secondary battery 12.

  The vehicle power supply device 11 is connected to a load 21 and an alternator 22 made of various electrical components of the vehicle, and the power supply to the load 21 is performed from the secondary battery 12 or the alternator 22. The alternator 22 also supplies charging power for charging the secondary battery 12.

  In the vehicle power supply device 11 having the configuration shown in FIG. 2, in order to determine the deterioration state of the secondary battery 12, the secondary battery 12 is discharged or charged at a predetermined timing. When the predetermined current is discharged from the secondary battery 12, the discharge circuit 16 is connected to the secondary battery 12 to cause the discharge. Further, when the secondary battery 12 is charged, it is charged with the current from the alternator 22. That is, in this embodiment, the alternator 22 is used as the charging circuit. In this case, in order to bypass the discharge circuit 16, a current flows through the path 19.

  When the secondary battery 12 is discharged or charged as described above, the current and voltage at that time are measured by the current sensor 13 and the voltage sensor 14, respectively, and the measured current value and voltage measurement value are measured by the control unit 17. To send.

  When the control unit 17 inputs the current measurement value and the voltage measurement value from the current sensor 13 and the voltage sensor 14, respectively, the control unit 17 calculates the internal impedance or the internal resistance of the secondary battery 12 by a method described later based on the current measurement value and the voltage measurement value. Determine the degradation state. The control unit 17 also determines whether the secondary battery 12 is to discharge or charge the predetermined current at the predetermined timing, and turns on / off the connection with the discharge circuit 16 based on the determination result.

  In determining whether to discharge or charge the predetermined current, for example, a charge / discharge selection signal is set in advance in the storage unit 18, and the control unit 17 reads the charge / discharge selection signal from the storage unit 18. It can be determined whether charging or discharging.

  The vehicle power supply device 11 of the present invention further includes a temperature sensor 15. The temperature sensor 15 is installed in the vicinity of the secondary battery 12, measures the temperature of the secondary battery 12, and sends the measured temperature to the control unit 17.

  In the present embodiment, an alternating current having a frequency of 100 Hz or more or a pulsed current is used as the predetermined current when the secondary battery 12 is charged or discharged. However, when a pulsed current is used, the current and voltage measured within 10 ms after applying the pulsed current are used to calculate the internal resistance. By setting the predetermined current as described above, it is possible to minimize the influence of noise from the alternator 22 or the load 21.

  Whether the predetermined current is an alternating current having a frequency of 100 Hz or more or a pulsed current is determined by the control unit 17 by reading a cross flow selection signal from the storage unit 18 and based on the cross flow selection signal. You can make it. In order to apply an alternating current having a frequency of 100 Hz or more to the secondary battery 12 by the current from the alternator 22, it is necessary to provide a predetermined charging circuit instead of the path 19.

  Next, temperature characteristics of the internal impedance and internal resistance of the secondary battery 12 will be described with reference to FIG. FIG. 1 is a graph showing an example of the temperature characteristics of a secondary battery, where the vertical axis represents the internal impedance and the horizontal axis represents the temperature of the secondary battery. In the same figure, graph 1 is a graph which shows the magnitude | size of the internal impedance of the secondary battery measured at each temperature. In addition, the Example of FIG. 1 has shown the thing when the internal impedance of the secondary battery 12 is measured using the alternating current of frequency 100Hz.

  From FIG. 1, it can be seen that the internal impedance of the secondary battery increases as the temperature decreases, and rapidly increases particularly at freezing temperatures. The temperature characteristic shown in the figure also changes depending on the usage period of the secondary battery, and has a characteristic (aging deterioration) in which the internal impedance increases as the usage period becomes longer. In the above description, the temperature characteristics of the internal impedance have been described. However, the internal resistance measured using a direct current also has the same temperature characteristics.

  Since the secondary battery 12 for vehicles is generally used over a wide temperature range, the secondary battery 12 needs to have appropriate internal impedance and internal resistance within the operating temperature range. Therefore, in determining the deterioration state of the secondary battery 12 in the control unit 17 of the vehicle power supply device 11, the above temperature characteristics of the internal impedance or internal resistance of the secondary battery 12 can be accurately evaluated. Is important.

  Therefore, in the secondary battery deterioration determination method of the present invention, a predetermined temperature characteristic function that accurately represents the temperature characteristic of the internal impedance or internal resistance of the secondary battery 12 is created and used in advance. The secondary battery deterioration determination method of the present invention measures the temperature of the secondary battery 12 simultaneously with the measurement of current and voltage, and calculates the internal impedance or internal resistance of the secondary battery 12 calculated from the current measurement value and the voltage measurement value. Conversion to internal impedance or internal resistance at a predetermined reference temperature is performed using the predetermined temperature characteristic function.

ここで、二次電池１２の内部インピーダンスをＺ、内部抵抗をＲ、二次電池１２の温度をＴemp、前記調整パラメータをＣとし、ｆ、ｇをＣの関数としている。 The temperature characteristic function used in the secondary battery deterioration determination method of the present invention is characterized by including at least one exponential term and one adjustment parameter. An example of the temperature characteristic function is shown in equation (1).

Here, the internal impedance of the secondary battery 12 is Z, the internal resistance is R, the temperature of the secondary battery 12 is Temp, the adjustment parameter is C, and f and g are functions of C.

  In the formula (1), the formula includes only one exponent term, but an exponent term may be further added. In any case, the number of exponential terms and the function forms of the functions f (C) and g (C) are determined so that the expression (1) can accurately represent the internal impedance Z or the internal resistance R of the secondary battery 12. FIG. 1 is a graph 2 showing an example of the internal impedance represented by the expression (1). A specific function form of the temperature characteristic function shown in the graph 2 is shown in the following equation.

（２）式では、Ｃ、ｆ、ｇをそれぞれ以下のように設定している。
Ｃ＝8.176 （３）
ｆ（Ｃ）＝0.6648×Ｃ＝5.435 （４）
ｇ（Ｃ）＝-2.790×Ｃ＝-22.81 （５）
同図に示す通り、（２）式で算出される内部インピーダンス(グラフ２)は、測定値(グラフ１)と良い一致を示しており、Ｒ^２＝０．９９８５４となっている。

In the equation (2), C, f, and g are set as follows.
C = 8.176 (3)
f (C) = 0.6648 × C = 5.435 (4)
g (C) =-2.790 × C = -22.81 (5)
As shown in the figure, the internal impedance (graph 2) calculated by the equation (2) is in good agreement with the measured value (graph 1), and R ² = 0.99985.

  In the secondary battery deterioration determination method of the present invention, first, the internal impedance Z or the internal resistance R is calculated from the measured current value and the measured voltage value when the secondary battery is discharged or charged. Further, since the temperature of the secondary battery at this time is also measured, the value of the adjustment parameter C is determined by substituting the calculated internal impedance Z or internal resistance R and the temperature measurement value Temp into the equation (1). To do.

  The temperature characteristics of the internal impedance or internal resistance of the secondary battery change due to deterioration over time after the start of use. The adjustment parameter C is for adjusting the change of the temperature characteristic due to such aged deterioration or the like so that the equation (1) matches the temperature characteristic at that time.

  When the value of the adjustment parameter C is determined, a predetermined reference temperature Tx is substituted for the temperature Temp in the equation (1) using the determined C value. As a result, the internal impedance or internal resistance at the predetermined reference temperature Tx is calculated from the equation (1). The deterioration state of the secondary battery 12 can be determined by comparing the calculated internal impedance or internal resistance with a predetermined threshold value.

  Next, an example of a specific processing flow for determining the deterioration state of the secondary battery 12 in the vehicle power supply device 11 according to the present embodiment will be described below with reference to FIG. FIG. 3 is a flowchart showing a flow of arithmetic processing mainly executed by the control unit 17. The calculation process shown in FIG. 3 is started in the vehicle power supply device 11 at a predetermined timing set in advance. FIG. 3 shows an embodiment in which the deterioration state of the secondary battery 12 is determined based on the internal impedance. However, when the deterioration determination is performed based on the internal resistance, the internal impedance in FIG. Replace with resistance.

  In FIG. 3, when the predetermined timing is reached, calculation processing in the control unit 17 is started. First, in step S101, parameters necessary for calculation are initially set. The setting values of each parameter can be set by reading the values stored in advance in the storage unit 18 from the storage unit 18 in step S101.

  The parameters to be initially set in step S101 include the reference temperature Tx for estimating the internal impedance or internal resistance, the internal impedance for determining the deterioration state of the secondary battery 12, and the determination thresholds Zth and Rth for the internal resistance. is there. Further, the charge / discharge selection signal and the cross flow selection signal can also be read from the storage unit 18 in step S101. Further, when the controller 17 instructs the discharge circuit 16 or the alternator 22 to discharge or charge, the frequency of the alternating current or the pulse width of the pulsed current is read from the storage unit 18 in step S101. You may make it to set.

  An appropriate initial setting value according to the characteristics of the secondary battery 12 can be fixedly set in advance, but the initial setting value is appropriately changed according to the operating state of the secondary battery 12 and aging deterioration. You may be able to do it.

  Next, in step S102, the discharge circuit 16 or the alternator 22 discharges or charges a predetermined current of an alternating current or a pulsed current, and the current measurement value and the voltage measurement from each of the current sensor 13 and the voltage sensor 14 at predetermined timing. Get the value.

  In step S103, the internal impedance Z of the secondary battery 12 is calculated by a technique such as Fourier expansion using the current measurement value and the voltage measurement value acquired in step S102. When calculating the internal resistance R, the internal resistance R can be calculated at R = dV / dt from the voltage change dV at a predetermined time dt of 10 ms or less from the start of discharging or charging the pulsed current.

  In step S104, the temperature measurement value Tp of the secondary battery 12 when the discharging or charging is performed is input from the temperature sensor 15. In step S105, the internal impedance Z calculated in step S103 and the temperature measurement value Tp input in step S104 are substituted into equation (1), and the adjustment parameter C is calculated from the equation.

Next, in step S106, the internal impedance Zx at the reference temperature Tx is calculated from the equation (1) using the reference temperature Tx set in step S101 and the adjustment parameter C calculated in step S105.

  Next, in step S107, the internal impedance Zx at the reference temperature Tx calculated in step S106 is compared with the determination threshold value Zth set in step S101, and the magnitude relationship is evaluated. When the internal impedance Zx is evaluated to be equal to or less than the determination threshold value Zth, that is, when Zx ≦ Zth is evaluated, it is determined that the secondary battery 12 has not deteriorated, and the process ends.

  On the other hand, when it is evaluated in step S107 that the internal impedance Zx exceeds the determination threshold value Zth, that is, when Zx> Zth is evaluated, the secondary battery 12 may be deteriorated. Determined. In the deterioration determination method of the present embodiment shown in FIG. 3, the secondary battery 12 is deteriorated when the determination in step S <b> 107 is continuously performed a predetermined number of times in order to reliably perform the deterioration determination of the secondary battery 12. I am trying to judge.

  That is, if it is determined in step S107 that there is a possibility that the secondary battery 12 has deteriorated, it is determined in step S108 whether or not the above determination has been made continuously for the predetermined number of times. As a result, when it is determined that the secondary battery 12 has deteriorated continuously for the predetermined number of times, the process proceeds to step S109 to perform the deterioration determination process of the secondary battery 12. As described above, the reason for confirming that the deterioration determination has been performed continuously a predetermined number of times is to suppress the influence of the fluctuation of the internal impedance and wait for the determination result to be stabilized.

  Next, a vehicle power supply system including the vehicle power supply device of the present invention will be described below. FIG. 4 is a block diagram showing an embodiment of the vehicle power supply system of the present invention. The vehicle power supply system 31 includes a vehicle power supply device 11, an input device 32, and a display device 33.

  The input device 32 and the display device 33 are connected to the control unit 17 and configured to input / output data. When it is determined in step S109 in FIG. 3 that the secondary battery 12 is deteriorated, the result is sent from the control unit 17 to the display device 33 to be displayed, so that the driver can be notified of the deterioration of the secondary battery 12. Can be.

  Further, the input device 32 includes, for example, a determination threshold for internal impedance of the secondary battery 12, a determination threshold for internal resistance, the charge / discharge selection signal, the cross current selection signal, the frequency of the alternating current, and the pulse of the pulsed current. It can be used to set the width in the storage unit 18. In the embodiment of FIG. 4, the storage unit 18 is configured to be set via the control unit 17.

  By configuring the vehicle power supply system of the present invention as described above, it is possible to report the deterioration of the secondary battery 12 to the driver quickly and easily. Therefore, it is possible to perform an appropriate process corresponding to the operating state of the secondary battery 12 and aging deterioration.

  In the above description, the vehicle power supply system having the configuration for determining the deterioration state of the vehicle secondary battery mounted on the vehicle has been described. However, the present invention is not limited to the vehicle secondary battery, The present invention can be widely applied to various power supply systems equipped with secondary batteries.

FIG. 1 is a graph showing an example of the temperature characteristics of a secondary battery, where the vertical axis represents the internal impedance and the horizontal axis represents the temperature of the secondary battery. FIG. 2 is a block diagram illustrating a schematic configuration of the vehicle power supply device according to the present embodiment. FIG. 3 is a flowchart showing a flow of arithmetic processing mainly executed by the control unit 17. FIG. 4 is a block diagram showing an embodiment of the vehicle power supply system of the present invention.

Explanation of symbols

1, 2 ... Internal impedance graph 11 ... Vehicle power supply device 12 ... Secondary battery 13 ... Current sensor 14 ... Voltage sensor 15 ... Temperature sensor 16 ... Discharge circuit 17 ... Control unit 18 ... Storage unit 19 ... Route 21 ... Load 22 ... Alternator 31 ... Vehicle power supply system 32 ... Input device 33 ... Display device

Claims (13)

A secondary battery deterioration determination method for determining a deterioration state of the secondary battery based on an internal impedance or an internal resistance of a secondary battery that supplies power to a load,
A predetermined temperature characteristic function including at least one exponential term and one adjustment parameter, and representing a temperature dependency of the internal impedance or the internal resistance in advance;
Calculate the internal impedance or the internal resistance based on a current measurement value and a voltage measurement value when the secondary battery is charged or discharged at a predetermined current,
The value of the adjustment parameter by substituting the temperature measurement value of the secondary battery and the calculated internal impedance or internal resistance when the secondary battery is charged or discharged at the predetermined current into the temperature characteristic function Decide
Substituting the value of the determined adjustment parameter and a predetermined reference temperature into the temperature characteristic function to calculate a reference internal impedance or a reference internal resistance,
A secondary battery deterioration determination method, wherein a deterioration state of the secondary battery is determined based on the calculated reference internal impedance or reference internal resistance. When the internal impedance is Z, the internal resistance is R, the adjustment parameter is C, and the temperature of the secondary battery is Temp,

(Where f and g represent predetermined functions)
The secondary battery deterioration determination method according to claim 1, wherein: A first determination threshold for performing deterioration determination based on the reference internal impedance and a second determination threshold for performing deterioration determination based on the reference internal resistance are set in advance, respectively.
When calculating the reference internal impedance, evaluate the magnitude relationship between this and the first determination threshold,
When calculating the reference internal resistance, evaluate the magnitude relationship between this and the second determination threshold,
The secondary battery deterioration determination method according to claim 1, wherein the deterioration state of the secondary battery is determined based on any one of the magnitude relationships. 4. The internal impedance is calculated based on the measured current value and the measured voltage value when the alternating current having a frequency of 100 Hz or more is charged or discharged as the predetermined current. The secondary battery deterioration determination method according to any one of the above. The pulse resistance is charged or discharged as the predetermined current, and the internal resistance is calculated based on the measured current value and the measured voltage value within 10 ms after the start of the charging or discharging. The secondary battery deterioration determination method according to claim 1. A secondary battery deterioration determination device that determines a deterioration state of the secondary battery based on an internal impedance or an internal resistance of a secondary battery that supplies power to a load,
A charging circuit for charging the secondary battery with a predetermined current;
A discharge circuit for discharging a predetermined current from the secondary battery;
A current sensor for measuring the current of the secondary battery;
A voltage sensor for measuring a voltage of the secondary battery;
A temperature sensor for measuring the temperature of the secondary battery;
A current measurement value, a voltage measurement value, and a temperature measurement value when the secondary battery is charged or discharged with a predetermined current by the charging circuit or the discharging circuit are input from the current sensor, the voltage sensor, and the temperature sensor, respectively. The internal impedance or the internal resistance is calculated based on the current measurement value and the voltage measurement value, and the temperature dependence of the internal impedance or the internal resistance includes at least one exponential term and one adjustment parameter. Substituting the calculated internal impedance or internal resistance and the measured temperature value into the temperature characteristic function to determine the value of the adjustment parameter, and determining the value of the determined adjustment parameter and a predetermined reference temperature as the temperature The reference internal impedance or the reference internal resistance is calculated by substituting into the characteristic function, and the calculated reference internal impedance is calculated. Secondary battery deterioration determination device, characterized in that it comprises a determining control means the deterioration state of the secondary battery based on the dance or the reference internal resistance. Storage means for storing in advance a first determination threshold value for performing deterioration determination based on the reference internal impedance and a second determination threshold value for performing deterioration determination based on the reference internal resistance;
When the reference internal impedance is calculated, the control means reads the first determination threshold value from the storage means, evaluates the magnitude relationship with the reference internal impedance, and calculates the reference internal resistance. The second determination threshold value is read from the storage means, the magnitude relation with the reference internal resistance is evaluated, and the deterioration state of the secondary battery is judged based on any of the magnitude relations. Item 7. The secondary battery deterioration determination device according to Item 6. The storage means stores a charge / discharge selection signal for charging or discharging the predetermined current to the secondary battery,
The control means reads the charge / discharge selection signal from the storage means and outputs a predetermined command signal to either the charging circuit or the discharge circuit based on the charge / discharge selection signal. The secondary battery deterioration determination device according to claim 7. The storage means stores a cross current selection signal that specifies whether the predetermined current is an alternating current having a frequency of 100 Hz or higher or a pulsed current,
The control means reads the cross current selection signal from the storage means, selects either an alternating current having a frequency of 100 Hz or more or a pulsed current based on the cross current selection signal, and selects the charging circuit or the discharging circuit. The secondary battery deterioration determination device according to claim 7 or 8, wherein a predetermined control signal is output to the circuit. The storage means stores the frequency of the alternating current and / or the pulse width of the pulsed current,
The control means reads the frequency of the alternating current and / or the pulse width of the pulsed current from the storage means, and simultaneously with the predetermined control signal for the charging circuit or the discharging circuit or prior to the predetermined control signal 10. The secondary battery deterioration determination device according to claim 9, wherein a frequency of the alternating current and / or a pulse width of the pulsed current is set in the charging circuit or the discharging circuit. The power supply system provided with the secondary battery deterioration determination apparatus of any one of Claims 6-10. The power supply system according to claim 11, further comprising display means for inputting and displaying a deterioration state determination result of the secondary battery from the secondary battery deterioration determination device. An input unit for changing data stored in the storage unit;
Any or all of the first determination threshold, the second determination threshold, the charge / discharge selection signal, the cross current selection signal, the frequency of the alternating current, and the pulse width of the pulsed current from the input means The power supply system according to claim 11, wherein the power supply system can be changed.

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