JP2003297435A - Device for estimating life of storage battery and device for controlling storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for estimating a service life of a storage battery with high precision. <P>SOLUTION: The device comprises a temperature sensor 3 for detecting the temperature of the storage battery 2, a current sensor 4 for detecting the input/output currents of the storage battery 2, and a computation controller 5 having a power storage amount detecting means for detecting the amount of power stored in the storage battery 2 from an integrated value of the currents detected by the current sensor 4. The computation controller 5 has a degradation speed calculating means for calculating the degradation speed of the storage battery 2 from an average temperature and an average current value of the battery 2 and the amount of the power stored in the battery 2, and a life calculating means for calculating the service life of the battery 2 by dividing a preset degradation characteristic value by the degradation speed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery life predicting device for predicting the life of a storage battery which varies depending on the use condition, and a storage battery control device for controlling the use condition so as to extend the life of the storage battery. is there.

[0002]

2. Description of the Related Art A storage battery (battery) is used in various fields and environments such as a starter of an automobile, an uninterruptible power supply or a solar power generation system, and plays a large role as electric power for each. Therefore, it is very important to know the life of the storage battery in each field.

For example, in Japanese Unexamined Patent Publication No. 2000-228227, the storage amount (SOC: state of cha) of a storage battery is set.
rge) and the temperature, the deterioration rate of the battery capacity is integrated, and this is subtracted from the initial battery capacity to calculate the battery capacity at a predetermined time.

[0004]

However, depending on the field in which the storage battery is used, the life of the storage battery may not be sufficiently predicted only by considering the charge state and temperature of the storage battery. For example, in a hybrid vehicle using a storage battery as a drive source, it is required to predict the life of the storage battery with high accuracy, and the above-described conventional technique has a problem that the demand cannot be sufficiently satisfied. Further, when the life of the storage battery can be predicted, it has been demanded to control the storage battery so as to extend the life.

The present invention has been made in view of such circumstances, and even in a field where it is desired to predict the life of a storage battery with high accuracy such as in a hybrid vehicle, the life of the storage battery is highly accurate. It is an object of the present invention to provide a storage battery life prediction device capable of predicting. Another object of the present invention is to provide a control device for a storage battery, which can extend the life of the storage battery.

[0006]

The invention described in claim 1 is a temperature detector for detecting the temperature of a storage battery (for example, a storage battery 2 in the embodiment described later) (for example, a temperature sensor in the embodiment described later). 3), a current detector for detecting the input / output current of the storage battery (for example, a current sensor 4 in the embodiment described later), and a storage for detecting the storage amount of the storage battery from the integrated value of the current detected by the current detector. An arithmetic controller having an amount detecting means (for example, arithmetic controller 5 in the embodiment described later) is provided, and the arithmetic controller calculates the deterioration rate of the storage battery from the average temperature of the storage battery, the average current value, and the stored amount. Life of a storage battery, comprising: a deterioration rate calculation means; and a life calculation means for calculating an allowable deterioration amount of the storage battery and dividing the allowable deterioration amount by the deterioration speed to calculate a life time. Prediction device (e.g., life prediction apparatus 1 battery in the embodiment described below) it is.

The present invention was made by the inventor's knowledge that the deterioration rate of a storage battery largely depends on the temperature of the storage battery, the input / output current of the storage battery, and the amount of electricity stored in the storage battery. According to the present invention, the temperature of the storage battery detected by the temperature detector, the input / output current of the storage battery detected by the current detector, and the change in the storage amount of the storage battery detected by the storage amount detection means of the arithmetic controller. Since the deterioration speed of the storage battery is calculated by the deterioration speed calculation means based on the width, it is possible to obtain the deterioration speed of the storage battery which varies according to the usage conditions. In addition, by calculating the permissible deterioration amount of the storage battery by the life calculation means and dividing the permissible deterioration amount by the deterioration speed of the storage battery, it is possible to highly accurately predict the life time of the storage battery, which varies according to the usage conditions. You can

According to the second aspect of the invention, a temperature detector for detecting the temperature of the storage battery, a current detector for detecting the input / output current of the storage battery, and an integrated value of the current detected by the current detector are used to detect the storage battery. An arithmetic controller (for example, arithmetic controller 21 in the embodiment described later) having an electricity storage amount detecting means for detecting an electricity storage amount, wherein the arithmetic and control unit is based on an average temperature, an average current value, and an electricity storage amount of a storage battery. A deterioration speed calculation means for calculating the deterioration speed of the storage battery is provided, and the deterioration speed reduction control means for decreasing the deterioration speed of the storage battery when the deterioration speed becomes a predetermined value or more (for example, arithmetic controller 21 in the embodiment described later) is operated. A control device for a storage battery (for example, a control device 20 for a storage battery in an embodiment described later) characterized by the above.

According to the present invention, similarly to the case of the first aspect of the present invention, it is possible to obtain the deterioration rate of the storage battery which varies depending on the use condition. In addition, when the deterioration speed is equal to or higher than a predetermined value, the deterioration speed of the storage battery is decreased by operating the deterioration speed lowering control means, so that the rapid deterioration of the storage battery can be prevented and the life of the storage battery can be prevented. Can be secured above a certain level.

A third aspect of the present invention is the second aspect of the present invention, wherein the deterioration rate reduction control means provides a cooling device provided to the storage battery when the deterioration rate exceeds a predetermined value (for example, an embodiment described later). Fan 22) in the form of
It is a control device for a storage battery, which is provided with a cooling control means for activating.

According to the present invention, the deterioration rate of the storage battery can be reduced while maintaining the planned input / output current of the storage battery. Therefore, the life of the storage battery can be secured for a certain period of time or more without limiting the operation of the storage battery.

The invention according to claim 4 is the invention according to claim 2 or 3, wherein current limiting means (for example, which will be described later) limits the input / output current of the storage battery when the deterioration rate exceeds a predetermined value. Input / output controller 2 in the embodiment
3) A storage battery control device comprising:

According to the present invention, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be more reliably ensured for a certain time or longer.

A fifth aspect of the present invention is the charge-discharge method according to any one of the second to fourth aspects, wherein the upper limit value of the amount of electricity stored in the storage battery is reduced when the deterioration rate becomes a predetermined value or more. A storage battery control device comprising a range limiting means. According to the present invention, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be ensured more reliably.

The invention according to claim 6 is the invention according to any one of claims 2 to 5, wherein the deterioration speed reduction control means is arranged so that when the deterioration speed exceeds a predetermined value, the amount of electricity stored in the storage battery is increased. The storage battery control device is provided with a charging / discharging range limiting means for increasing the lower limit value of.
According to the present invention, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be more reliably ensured for a certain time or longer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A storage battery life prediction apparatus and a storage battery control apparatus according to embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, a case of predicting the life of a storage battery mounted on a hybrid vehicle and a case of controlling the life of the storage battery will be described as an example.

FIG. 1 is a block diagram showing a storage battery life predicting apparatus 1 (hereinafter, simply referred to as "life predicting apparatus 1") according to a first embodiment of the present invention. As shown in FIG. 1, the life prediction apparatus 1 includes a temperature sensor 3 for detecting the temperature of the storage battery 2, a current sensor 4 for detecting the input / output current of the storage battery 2, and the storage battery 2 An arithmetic and control unit (EC having an electricity storage amount detecting means for detecting an electricity storage amount)
U) 5.

The current sensor 4 is provided on the connection path between the storage battery 2 and the electric motor (motor / generator) 6 so as to detect the current when the storage battery 2 is charged and discharged. The arithmetic controller 5 is connected to the temperature sensor 3 and the current sensor 4, and the temperature and current of the storage battery 2 detected by these sensors 3 and 4 are input to the arithmetic controller 5.

Further, the arithmetic and control unit 5 is provided with a storage amount detecting means (not shown) therein, so that the storage amount of the storage battery 2 can be detected from the integrated value of the current detected by the current sensor 4. I have to. The arithmetic controller 5 is connected to the ignition 7 and receives a signal from the ignition 7 to perform an arithmetic process described later. And
The arithmetic and control unit 5 is connected to the life estimation display unit 8 so that the life estimation display unit 8 can display the life calculated by the arithmetic and control unit 5.

When the electric motor 6 functions as a motor, the storage battery 2 supplies drive power to the motor. On the other hand, when the electric motor 6 functions as the generator 6, regenerative electric power is supplied from the generator. As described above, the usage state of the storage battery 2 varies in various ways.

The inventor has found that the deterioration rate of the storage battery 2 is such that the temperature T, the input / output current (current load), and the fluctuation range of the amount of electricity stored in the storage battery (charge / discharge range represented by charge depth or discharge depth).
Based on the finding that it greatly depends on and, we derived the relational expression between them. The contents are shown below.

When the deterioration rate of the storage battery 2 is K and the variable of the usage condition is X, these can be expressed by the following equation (1). Formula (1): K = f (X) This function f (X) tends to be approximated by an exponential function almost exactly.

Further, in the above equation (1), the variable X is X
If the deterioration rates in the cases of 1 and X2 are K1 and K2, the ratio Q (K2 / K1) tends to be substantially the same even if the conditions of other variables Y change.

For example, when K = f (X) is a correlation expression of the temperature T, the deterioration speed ratio Q1 when the current value is I1 and the deterioration speed ratio Q2 when the current value is I2 show substantially the same value. . This holds because there are few interactions between each use condition.

Based on the above findings, the present inventor has confirmed that the deterioration rate K can be expressed by the following equation (2). Formula (2): K = ft (T) × fi (I) × fs (S) where ft (T) is a term dependent on the temperature T, fi (I)
Is a term depending on the current value I, and fs (S) is a fluctuation range S of the stored amount.
Is a term that depends on.

The deterioration rate R is obtained by dividing the allowable deterioration rate R of the storage battery measured in advance by an experiment by the deterioration rate K.
The life time L of the storage battery 2 that reaches That is, the formula (3): L = R / K These formulas (2) and (3) can be used to easily estimate the life time L of the storage battery 2. The allowable deterioration amount R will be described in detail later.

Hereinafter, the form of the equation (2) will be calculated more concretely. The present inventor has found that the Arrhenius equation (4) when the deterioration rate K depends only on the temperature T: Equation (4): K = Λe ^{(-ΔE / (kT)} (where Λ is a constant) and the temperature T And other stress factors S
Eyring's equation (5) including one equation (5): K = a ((kT) / h) · e ^{(-ΔE / (kT))} ·
The following equation (6) was derived based on S ^α . Formula (6): K = a ((kT) / h) ・ e ^{(-ΔE / (kT))}・
S ^α · S '^α'where S is the current load and S'is the fluctuation range of the amount of stored electricity, which is a stress factor other than temperature. h is Planck's constant, k is Boltzmann's constant, ΔE is activation energy, T
Is the absolute temperature.

In order to obtain the coefficient of the above equation (6), the relationship between the deterioration rate K and each variable (current load, charge amount, temperature) is obtained using FIGS. 3 to 5 as follows. When the logarithm of both sides is taken by focusing on one of the three variables (for example, current load) in the equation (6), the equation (6) is as follows. Formula (7): lnK = A + αlnS where A and α are constants. These values are obtained from FIG.

FIG. 3 is a graph showing the current load characteristics of the storage battery 2. The vertical axis represents the logarithm of the internal resistance deterioration rate K (% / hr), and the horizontal axis represents the logarithm of the current load S (C). In the figure, the conditions of the temperature and the amount of stored electricity are constant so as not to be affected by other variables. From FIG. 3, the coefficients A and α of this equation (7) are equation (8): A = −3.5, α = 1.00.

Similarly, paying attention to the amount of electricity stored in the equation (6), the equation (9): lnK = A '+ α'lnS' where A'and α'are constants. These values are obtained from FIG. FIG. 4 is a graph showing the storage amount characteristic of the storage battery 2. The vertical axis represents the logarithm of the internal resistance deterioration rate K (% / hr), and the horizontal axis represents the logarithm of the fluctuation range (%) of the stored amount. In the figure, conditions of temperature and current load are constant so as not to be influenced by other variables. From FIG. 4, the coefficients A ′ and α ′ of this equation (9) are equation (10): A ′ = − 3.8, α = 0.32.

Similarly, focusing on the temperature T in the equation (6), the equation (11): lnK = A "-ΔE / (kT) = A"-
α ″ / T where A ″ and α ″ are constants, of which α ″ = ΔE /
k. These values are obtained from FIG. FIG. 5 is a graph showing the temperature characteristics of the storage battery 2. The vertical axis is the logarithm of the internal resistance deterioration rate K (% / hr), and the horizontal axis is the logarithm of the reciprocal 1 / T (K) of the absolute temperature. In the figure, the conditions of the fluctuation range of the current load and the stored amount are constant so as not to be influenced by other variables. From FIG. 5, the coefficients A ″ and α ″ of this equation are given by Equation (12): A ″ = 11, α ″ = − 4600.

From the above, the deterioration rate (internal resistance deterioration reaction rate) K of the storage battery is expressed by the following equation (13). Formula (13): K = dR / dt = 55T · e ^{(-4600 / T)} ·
S ¹ · S ′ ^0.32 Degradation speed K
The value of can be obtained. Here, R is a permissible deterioration amount of the storage battery 2, t is a specified time, and the permissible deterioration amount R is a value indicating a deterioration amount until the life of the storage battery is reached and a sufficient charging / discharging function cannot be obtained. It is obtained by measurement by experiments under various usage conditions. Then, the deterioration rate K is calculated by the formula (2)
By substituting into, the life time L of the storage battery 2 can be obtained.

For example, when the storage battery 2 is used under the conditions of a temperature of 50 ° C., a current value of 2 C and a fluctuation range of the stored amount of 20%, the reaction rate K is 0.061 (% / h
r), and the allowable deterioration amount R until the end of the life is 30
When the life time in the case of% is calculated from the equation (2), it is 490
hr is obtained. In this way, the deterioration rate K
And the life time L can be calculated. FIG. 6 shows a storage battery 2
It is the data which experimented the life time of each for every use condition. In the figure, the life time is measured assuming that the allowable deterioration amount R is 30%.

FIG. 2 is a flow chart of the life prediction device 1 shown in FIG. As shown in step S10 of the figure, when the ignition 7 is turned on, the signal is input to the arithmetic controller 5 and a timer (not shown) is activated,
Start measuring the specified time. Then, the fluctuation range of the temperature of the storage battery 2, the current load, and the amount of stored electricity, which are variables of the deterioration rate K, are sampled for each specified measurement time. As shown in step S12, it is determined whether or not the sampling time has reached the specified measurement time. If the determination result is “YES”, the process proceeds to step S14, and if the determination result is “NO”, the step The process returns to S10 and the above process is repeated.

In step S14, a representative value (representative value of use environment condition, for example, average value) of each variable (temperature, etc.) is calculated every prescribed time. Then, in step S16, the deterioration rate K is calculated by substituting the representative value of each variable into the equation (13). In the present embodiment, the deterioration rate K is displayed on the life estimation display 8 to show the degree of influence on the current storage battery 2.

In step S18, the deterioration amount Ri obtained by multiplying each deterioration rate K calculated for each specified time by the specified time is integrated to calculate an integrated deterioration amount ΣRi. Then, as shown in step S20, the remaining allowable deterioration amount R is calculated by subtracting the integrated deterioration amount ΣRi from the initial allowable deterioration amount R0 of the storage battery 2. For example, when the initial allowable deterioration amount R0 is 30 (%) and the integrated deterioration amount is 10 (%),
The remaining allowable deterioration amount R is 20 (%). When the allowable deterioration amount R becomes 0 (%), the function of the storage battery becomes insufficient and the life of the storage battery is reached.

Then, as shown in step S22,
The estimated life time is calculated by dividing the calculated deterioration characteristic value by the reaction speed, and the process ends. Since it did in this way, the deterioration rate K of the storage battery 2 which changes according to a use condition can be calculated | required, and the life time L of the storage battery 2 which changes according to a use condition can be estimated with high precision.
By recording the history of the deterioration rate, it is possible to contribute to the analysis of the storage battery 2.

The control device for the storage battery will be described below. FIG. 7 is a block diagram showing a storage battery control device 20 (hereinafter, simply referred to as “control device 20”) in the embodiment of the present invention. Here, the same components as those of the life prediction apparatus 1 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

The control device 20 is provided with an arithmetic controller 21, which, like the arithmetic controller 5, calculates the deterioration rate K and the life time L of the storage battery 2 using the equation (13) or the equation ( It has a function to calculate by 2). Further, the arithmetic controller 21 is connected to a cooling fan 22 provided in the storage battery 2 and an input / output controller 23 connected to the electric motor 6 to control the cooling fan 22 and the input / output controller 23. I am trying.

FIG. 8 is a flowchart of the control device 20 shown in FIG. In the figure, steps S30 to S3
Since the process of 6 is the same as the process of steps S10 to S16 of FIG. 2, description thereof will be omitted.

In step S38, step S3
It is determined whether or not the deterioration rate K calculated in 6 is equal to or higher than the reference deterioration rate. If the determination result is “YES”, the process proceeds to step S40, and if the determination result is “NO”, the series of processes is temporarily terminated. .

When the result of the determination is "YES", the processing for reducing the deterioration rate of the storage battery 2 is performed as described below. That is, in step S40, the cooling fan 22 is operated to control the storage battery 2. As shown in FIG. 6, since the life time of the storage battery 2 decreases as the temperature increases, the deterioration rate K is reduced by extending the life of the storage battery 2 by performing the cooling control described above. Thereby, the life of the storage battery 2 can be ensured while maintaining the operation function of the storage battery 2.

Then, as shown in step S42, the deterioration rate K is calculated again and it is determined whether or not this is the reference deterioration rate. If the determination result is "YES", the process proceeds to step S44, and the determination result is " If “NO”, the series of processes is once ended.

In step S44, the input / output controller 2
A process for controlling the charge / discharge amount is performed by activating No. 3. As shown in FIG. 6, since the life time of the storage battery 2 decreases as the current load increases, the deterioration rate K is reduced by controlling the charge / discharge amount described above.
Are trying to extend their lives. As a result, the life of the storage battery 2 can be more reliably ensured for a certain time or longer.

Then, as shown in step S46, the deterioration rate K is calculated again, and it is determined whether or not this is equal to or higher than the reference deterioration rate. If the determination result is "YES", the process proceeds to step S48 and the determination result is " If “NO”, the series of processes is once ended.

In step S48, the storage battery 2
A process for controlling the fluctuation range of the stored power amount is performed. As shown in FIG. 6, since the life time of the storage battery 2 decreases as the fluctuation range of the stored amount increases, the deterioration rate K is reduced by controlling the fluctuation range described above to decrease. I am trying to extend my life. As a result, the life of the storage battery 2 can be more reliably ensured for a certain period of time or longer. The fluctuation range of the charged amount may be limited by decreasing the upper limit value of the charged amount, by increasing the lower limit value of the charged amount, or by both limits. May be.

In the embodiment, the case where the life prediction or life control of the storage battery applied to the hybrid vehicle is performed has been described, but the application range of the present invention is not limited to this, and for example, in a solar power generation system or the like. It can be applied in the case of performing life prediction and life control of storage batteries used in various fields and environments.

[0048]

As described above, according to the invention described in claim 1, it is possible to obtain the deterioration rate of the storage battery which varies according to the use condition, and the life time of the storage battery is calculated based on this deterioration rate. It can be predicted with high accuracy.

According to the second aspect of the present invention, it is possible to obtain the deterioration rate of the storage battery which varies depending on the usage conditions. In addition, when the deterioration rate is equal to or higher than a predetermined value, it is possible to prevent the rapid deterioration of the storage battery by operating the deterioration speed reduction control means, and to reduce the deterioration speed of the storage battery, so that the life of the storage battery is reduced. Can be secured for a certain time or longer.

According to the third aspect of the present invention, the deterioration speed of the storage battery can be reduced while maintaining the planned input / output current of the storage battery. Therefore, the operation of the storage battery is not limited and the life of the storage battery is limited. Can be secured for a certain time or longer. According to the invention described in claim 4, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be more reliably ensured.

According to the invention described in claim 5, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be more reliably ensured for a certain time or more.
According to the invention described in claim 6, the deterioration rate can be reduced in a shorter time, and the life of the storage battery can be more reliably ensured for a certain time or more.

[Brief description of drawings]

FIG. 1 is a block diagram showing a life estimation device for a storage battery according to an embodiment of the present invention.

FIG. 2 is a flowchart of the storage battery life prediction apparatus shown in FIG.

FIG. 3 is a graph showing current load characteristics of the storage battery shown in FIG.

FIG. 4 is a graph showing SOC fluctuation range characteristics of the storage battery shown in FIG. 1.

5 is a graph showing temperature characteristics of the storage battery shown in FIG.

FIG. 6 is data obtained by performing an experiment on the life time of the storage battery shown in FIG. 1 for each use condition.

FIG. 7 is a block diagram showing a control device for a storage battery according to an embodiment of the present invention.

8 is a flowchart of a control device for the storage battery shown in FIG.

[Explanation of symbols]

1 Battery life prediction device 2 storage battery 3 Temperature detector 4 current sensor 5 Operation controller (ECU) 20 Battery control device 21 Arithmetic controller 22 Cooling fan 23 I / O controller

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5G003 BA01 DA07 EA08 FA06 GC05                 5H030 AA03 AA04 AA06 AS08 BB01                       BB21 FF22 FF42 FF52                 5H031 AA01 AA02 AA09 KK01                 5H115 PA11 PA15 PG04 PI16 PU01                       PU21 SE06 TI09 TO05 TO12                       TO13 TR19

Claims (6)

[Claims] 1. A temperature detector for detecting the temperature of a storage battery,
A current detector for detecting the input / output current of the storage battery, and an arithmetic controller having a storage amount detection means for detecting the storage amount of the storage battery from the integrated value of the current detected by the current detector, the arithmetic controller, A deterioration rate calculating means for calculating the deterioration rate of the storage battery from the fluctuation range of the average temperature, the average current value of the storage battery and the amount of stored electricity, and the allowable deterioration amount of the storage battery is calculated, and the allowable deterioration amount is divided by the deterioration speed to determine the life. A life prediction device for a storage battery, comprising a life calculation means for calculating time. 2. A temperature detector for detecting the temperature of a storage battery,
A current detector for detecting the input / output current of the storage battery, and an arithmetic controller having a storage amount detection means for detecting the storage amount of the storage battery from the integrated value of the current detected by the current detector, the arithmetic controller, A deterioration speed calculation means for calculating the deterioration speed of the storage battery from the average temperature of the storage battery, the average current value, and the fluctuation range of the amount of stored electricity is provided, and a deterioration speed reduction control means for decreasing the deterioration speed of the storage battery when the deterioration speed becomes a predetermined value or more A storage battery control device characterized by being operated. 3. The storage battery according to claim 2, wherein the deterioration rate lowering control means includes a cooling control means that operates a cooling device provided in the storage battery when the deterioration rate becomes a predetermined value or more. Control device. 4. The deterioration rate lowering control means comprises current limiting means for limiting the input / output current to and from the storage battery when the deterioration rate becomes equal to or higher than a predetermined value. The storage battery control device described. 5. The deterioration rate lowering control means is provided with a charging / discharging range limiting means for reducing the upper limit value of the amount of electricity stored in the storage battery when the deterioration rate becomes equal to or higher than a predetermined value. Item 5. A storage battery control device according to any one of items 4. 6. The charging / discharging range limiting means for increasing the lower limit value of the amount of electricity stored in the storage battery when the deterioration speed reduction control means is equal to or higher than a predetermined value. Item 6. A storage battery control device according to any one of items 5.