JP2000039471A - Method and apparatus for deciding deterioration of secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide a deterioration of a secondary cell without a cell state, by giving first and second pulses having different continuous times within a transient time immediately after charging or discharging of the cell, and calculating peak hold voltages of the pulses. SOLUTION: The case of charging a nickel-cadmium battery via a constant current drive is as an example. The apparatus comprises a constant current driver 31 and a pulse generator 32, which are drivers of measurement by a conventional four terminal method. First and second constant current pulses having different continuous times to be driven are applied to the secondary cell 33 to be measured within a transient time immediately after starting of charging or discharging of the cell by the drivers. A voltage across the cell 33 at that time is measured by a voltage measuring unit 34, the voltage values are guided to a peak hold circuit 35 at each first and second pulse, and a peak hold voltage is detected. The detected peak hold voltage is calculated by an arithmetic deciding unit 35, and a deterioration of the cell 33 is decided based on a calculated result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called rechargeable secondary battery (hereinafter simply referred to as a secondary battery) of nickel-cadmium, nickel-hydrogen type, lithium ion type, and the like, as well as future assembled batteries. The present invention relates to a method and an apparatus for determining deterioration of a secondary battery, which determines deterioration of a large-capacity battery to be performed.

[0002]

2. Description of the Related Art A number of conventional methods for determining the deterioration of a secondary battery have been proposed. The main ones of them are
(1) A method for checking the internal resistance of a secondary battery, (2)
There is an AC impedance method in which an AC of 0.05 to several kHz is sequentially applied to obtain the AC impedance.

In the method of examining the internal resistance of a secondary battery, it is determined that the internal battery has deteriorated if the internal resistance greatly increases compared to the initial value. It depends on the manufacturer and product. Therefore, there is a problem that it is risky to determine the deterioration of the secondary battery only from the internal resistance.

Next, the AC impedance method has a problem that it takes a long time to measure and it is difficult to interpret it. Therefore, as a temporary simple determination method, a method has been adopted in which the magnitude of the impedance of the real part when the imaginary part is zero is determined. However, even in this case, the determination is made after the time-consuming measurement is completed. Furthermore, since the resistance depends on the type of each battery and the manufacturer, there is a problem that the reliability of the determination result is low.

[0005]

In the conventional method of judging the deterioration of a secondary battery, a full charge / discharge of the secondary battery is repeated several times, and then the measurement is performed by a predetermined method. The present invention has been made in view of the above circumstances, and is simple and relatively accurate in that deterioration information can be obtained regardless of the state of a secondary battery to be evaluated. An object of the present invention is to provide a method and an apparatus for determining deterioration of a secondary battery.

[0006]

Means for Solving the Problems To achieve the above object, the present invention provides a method for determining deterioration of a secondary battery, comprising the steps of:
Each of the first and second batteries having a different duration within a transient time immediately after the start of charging and / or discharging of the secondary battery.
One pulse is given, and the peak hold voltage of the detection voltage for the first and second pulses is calculated to determine the deterioration of the battery.

[0007] Further, the deterioration determination device for a secondary battery according to the present invention includes:
Each of the first and second batteries having a different duration within a transient time immediately after the start of charging and / or discharging of the secondary battery.
Means for flowing two constant current pulses, means for measuring the voltage across the rechargeable battery when the constant current pulse flows by this means, and detecting the peak hold voltage of the voltage across the rechargeable battery measured by this means A peak hold circuit, means for calculating the peak hold voltage of the first and second constant current pulses detected by the peak hold circuit, and deterioration of the secondary battery based on the calculation result calculated by the means. Determining means.

[0008] A secondary battery deterioration judging device according to the present invention comprises:
Each of the first and second batteries having a different duration within a transient time immediately after the start of charging and / or discharging of the secondary battery.
Means for providing two constant voltage pulses, means for measuring a current flowing through the secondary battery when the constant voltage pulse is applied by this means, a peak hold circuit for detecting a peak hold current of the current measured by this means, A means for calculating peak hold currents of the first and second constant voltage pulses detected by the peak hold circuit; and a means for determining deterioration of the secondary battery based on the calculation result calculated by the means. It is characterized by having.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. Hereinafter, embodiments of the present invention will be described using a nickel-cadmium battery as a typical example of a secondary battery. Further, the case of constant current driving and charging will be described as an example, but another configuration may be used, and the present invention is not limited to this example. That is, the other configuration is a nickel-hydrogen system, a lithium ion system, or a future secondary battery, and the same applies to the case where deterioration is determined by constant voltage driving or the case where discharging is performed instead of charging.

In the embodiment, the case of the first and second pulses will be described. However, the same applies to the case where the third and fourth pulses are applied after the second pulse. [Embodiment 1] FIG. 1A is a diagram showing the measurement principle of the four-terminal method in the case of constant current driving.

In FIG. 1A, 1 is a secondary battery, 2 is a constant current driving means, 3 is a battery terminal voltage detecting means at the time of charging,
4 is a circuit system. In the constant current driving means 2, when the secondary battery 1 is a nickel-cadmium battery, it is usually 1 C to 0.2 C (1 C is a current value required to charge or discharge the rated capacity in one hour). Drive with

FIGS. 1B and 1D show first and second pulse (constant current pulse) waveforms generated by the constant current driving means 2, respectively, and FIGS. 1C and 1E show charging waveforms. 5 shows first and second battery terminal voltage waveforms respectively detected by the battery terminal voltage detecting means 3 of FIG. FIG. 1 (b) and (d)
, 5 is the pulse width (t ₁ ) of the first constant current pulse, and 6 is the pulse width (t ₁ ) of the second constant current pulse.
₂ ) and 7 are constant current values.

In FIGS. 1 (c) and 1 (e), 8 and 9 denote the pulse widths (t) of the first and second constant current pulses.
Battery terminal voltage detecting means 3 at the time of charging corresponding to ₁ , t ₂ )
The detection voltage waveform 10 is a tail of the voltage observed when the relatively long constant current pulse shown in FIG. 1D is driven and cut off. Here, the peak hold voltages 8 'and 9' of the first and second detection voltages are set.
(Voltage values V ₁ and V ₂ ).

Here, it is known that the rising voltage (V ₁ ′) at the second constant current pulse is substantially equal to V ₁ shown in FIG. 1C (that is, V ₁ = V ₁ ′). .
The detection (charging) voltage (V ₁ ) corresponding to the first pulse width (t ₁ ) 5 and the rising portion voltage (V
₁ ') is a voltage due to the internal resistance component of the secondary battery 1 and, as illustrated in FIG. 2, has a value of several tens of milliohms in the case of a normal nickel-cadmium secondary battery.

FIG. 2 shows the internal resistance values of a normal nickel-cadmium secondary battery and a deteriorated secondary battery whose electrolyte is controlled. In FIG. 2, the number of times of use increases as the degree of deterioration C increases. Normal Nickel - the internal resistance of the cadmium rechargeable batteries (V ₁ in FIG. 1, and generates a V ₁ '), the number 10 milliohms, more precisely 30
Before and after the Milliome. On the other hand, the internal resistance of the deteriorated secondary battery in which the electrolyte solution is controlled increases,
Exceeds 0 milliohm. Therefore, it is possible to determine whether or not the internal resistance value has deteriorated even with the transition of the internal resistance value.

However, the deterioration of the battery may occur rapidly. In general, even if a value of several tens of milliohms is detected, the determination of the deterioration is not sufficient with this element alone. FIG.
Is the difference ΔV (ΔV = V ₂ −V ₁ ) between the peak hold voltage values of the first and second pulses when the drive pulse width is changed.
And the relationship between the pulse width. In both the case of a normal nickel-cadmium (Ni-Cd) secondary battery and the case of a deteriorated secondary battery in which an electrolyte solution is controlled, ΔV is a pulse width of 0.1.
After increasing in proportion to the quintuple (indicated by regions 21, 21 ', 21 "), a steady state (indicated by regions 22, 22', 22") is reached.

The proportional portion is within the transient time immediately after the start of charging, and indicates that the charged ion current follows the first-order diffusion law. Further, the steady state value indicates that charging is in a steady state and charging is performed with a substantially constant current.

Here, in the case of a normal nickel-cadmium secondary battery, the slope of ΔV is small (indicated by 23) in a portion where ΔV increases in proportion to 0.5 times the pulse width, and deterioration In the case of the next battery, the degree of deterioration B and the degree of deterioration C gradually increase in accordance with the degree of deterioration (indicated by 24 and 25). This is because, under the conditions of the present embodiment in which constant current driving is performed, the secondary battery terminal voltage is high because the internal resistance of the deteriorated secondary battery is high.

That is, in order to determine the deterioration of the secondary battery, the slope of ΔV may be determined in the “region where ΔV increases in proportion to the pulse width multiplied by 0.5” shown in region 21. . △
If V is used for determining deterioration with reference to the ion mobility and the magnitude of the conventional internal resistance value, the deterioration accuracy is further improved.

As one example of the determination, the following logic can be considered. In other words, (1) high V ₁ is (V ₂ -V
If ₁₎ is high, it is determined that the "deterioration", (2) if higher V ₁ is is (V ₂ -V ₁₎ is low, "but has deteriorated, but the time being use (which is charging the battery itself and is degraded) ", (3) V ₁ is low, (the higher V ₂ -V ₁₎ is,"it's normal but there cornerstone of charge ", low _{(4) V 1, (V} 2 - If V ₁ ) is low, it is determined to be “normal”.

In order to realize the first embodiment, the first pulse width (t ₁ ) is ₁ msec per cell.
c to 10 to several tens msec, and at least the second
The pulse width (t ₂₎ is the first pulse of the pulse width (t ₁₎
Longer than 1 sec, preferably 100 msec
It is preferable that the following is true, but t ₁ <t ₂ (t ₃ ...)
...), and this pulse is given within the transient time of the secondary battery.

As described above, the first embodiment includes the following method. (1) In a method of determining the deterioration of a secondary battery, first and second two pulses having different durations are given within a transient time immediately after the start of charging and / or discharging of the secondary battery, and the first and second pulses are given. A method for determining deterioration of a secondary battery, comprising calculating a peak hold voltage of a detection voltage for the first and second pulses and determining battery deterioration.

(2) In the method for judging deterioration of a secondary battery according to the above (1), the magnitude of the difference between the peak hold voltages corresponding to the pulse widths of the first and second pulses is made to correspond to the magnitude of the degradation. Characteristic method of determining deterioration of secondary battery.

(3) In the method for determining deterioration of a secondary battery according to (1), the voltage value corresponding to the first pulse and the magnitude of the difference between the peak hold voltages corresponding to the first and second pulses, respectively, are determined. A method for determining deterioration of a secondary battery, comprising determining the deterioration by combining the above information.

(4) In the method for judging deterioration of a secondary battery according to (1), (2) or (3), after the second pulse having a pulse width longer than the pulse width of the first pulse is given, at least A third pulse longer than the second pulse width, or a third pulse followed by a plurality of fourth or more constant current pulses are successively provided, and the respective peak hold voltages corresponding thereto are calculated and the battery is operated. A method for determining deterioration of a secondary battery, comprising determining deterioration of a secondary battery.

(5) In the method for judging deterioration of a secondary battery according to the above (1), (2), (3) or (4), the first pulse width per cell is from 1 msec to 10 to several tens.
msec, and at least the second pulse width is longer than the pulse width of the first pulse and is 1 sec or less, preferably 1 sec.
A method for judging deterioration of a secondary battery, wherein the method is not more than 00 msec.

(6) In the method for judging deterioration of a secondary battery according to the above (4) or (5), the constant current having the pulse width of the first, second, and third and subsequent pulses to be driven is charged and / or A method for judging deterioration of a secondary battery, which is a discharge current.

(7) In the method for judging deterioration of a secondary battery according to the above (4), (5) or (6), instead of the constant current having the pulse width of the first to third or more driving pulses. A secondary battery characterized in that a constant voltage having a pulse width of first to third or more pulses is applied, and a peak hold value of a charging or discharging current flowing through the battery is calculated to determine deterioration of the battery. Deterioration determination method.

FIG. 4 shows the first embodiment of the present invention.
3 is a block diagram illustrating an actual circuit configuration of FIG. In the figure, 31 is a constant current drive unit, 32 is a pulse generation unit,
The constant current pulse generating means 37 having a configuration in which these are integrated may be used. These are driving parts for measurement by the usual four-terminal method (see the constant current driving means 2 in FIG. 1A),
The first and second two constant current pulses having different durations driven by the driving section are applied to the secondary battery 33 to be measured within a transient time period immediately after the start of charging and / or discharging of the secondary battery. . The voltage measuring section 34 measures the voltage across the measured secondary battery 33 when the first and second two constant current pulses are applied to the measured secondary battery 33. The voltage value measured by the voltage measuring unit 34 is guided to a peak hold circuit 35 for each of the first and second pulses, and a peak hold voltage is detected. Peak hold circuit 3
The peak hold voltage of the first and second constant current pulses detected in step 5 is calculated in the calculation / determination unit 36, and the deterioration of the measured secondary battery 33 is determined based on the calculation result.

It is clear that this circuit has high practicality because the components are simple and the configuration is extremely simple, and the measurement is performed by a very general four-terminal method. The apparatus for determining deterioration of a secondary battery according to the present invention provides means for providing first and second two constant voltage pulses having different durations within a transient time immediately after the start of charging and / or discharging of the secondary battery. And means for measuring the current flowing through the secondary battery when a constant voltage pulse is applied by this means, a peak hold circuit for detecting the peak hold current of the current measured by this means, and detection by this peak hold circuit. First and second
And a means for calculating the peak hold current of the two constant voltage pulses and a means for determining the deterioration of the secondary battery based on the calculation result calculated by the means.

There are various means for giving a constant current pulse. The simplest equivalent of a measuring device is, for example, a constant current / constant voltage generator (manufactured by ADVANTEST,
R6246 type, voltage current so
source / monitor). In general, a normal power supply may be used with constant current or constant voltage driving. In the case of a short pulse, a general pulse generator may be used as an external trigger to generate a constant current or a constant voltage. In the case of a general-purpose machine, it is only necessary to combine dedicated parts. FIG. 5 shows an example of two extremely simple pulse generating circuits. In FIG. 5, 101 is a constant voltage power supply, 1
02 and 103 are R ₁ for controlling the peak value of the pulse,
A resistor having a value of R ₂ , 104 and 105 are switch circuits that are turned on / off by a gate signal (or a manual switch) not shown, 106 and 107 are input terminals of the gate signal not shown, and 108 and 109 are Output terminal for constant voltage pulse.

As means for measuring voltage and current, there are various general means, which can be easily analogized by a person skilled in the art and the configuration thereof is also easy. For example,
At the instrument level, you can use a regular oscilloscope and monitor the voltage with a voltage probe. The current probe may also be a commercially available one. For example, Tektronix (T
EKTRONIKS) current probe (AM503A)
Type) and can be monitored with a normal oscilloscope. Of course, it may be configured with small parts for general-purpose use.

As a means for calculating and judging the peak hold voltage, there are various methods for constructing the peak hold voltage. One example is a “sample and hold circuit”, which is described in the “Electronic Information and Communication Handbook”, first volume, p.
40 pages (edited by the Institute of Electronics, Information and Communication Engineers Handbook Committee, Ohmsha (1st edition, 1st edition, published March 30, 1988)
Printing). As described above, the present invention is different from the conventional case where a steady state value is detected or the case where deterioration is determined based on characteristic values in a steady state by measuring a complicated AC impedance. This is a judgment focusing on (based on) the transient phenomenon.

(1) It is possible to eliminate the trouble of performing a full charge / discharge cycle several times as in the prior art and then performing the measurement, and it is possible to make a determination regardless of the state of the secondary battery to be determined.

(2) It can be realized with simple parts and an extremely simple circuit configuration based on the measurement by the conventional four-terminal method. It is clear.

[0036]

As described above, according to the present invention, it is possible to judge deterioration regardless of the state of the secondary battery. (2) Since the circuit components and configuration are simple and based on the measurement by the ordinary four-terminal method, the reliability is simple and high.

(3) Accordingly, the present invention can be applied to a large-capacity power supply system (high-end user) requiring high reliability from a low-end level that can be installed at a user or a store, and has high versatility.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an internal resistance value of a normal nickel-cadmium secondary battery according to the present invention and a deteriorated secondary battery in which an electrolyte solution thereof is controlled.

FIG. 3 is a diagram showing a first case where the drive pulse width according to the present invention is changed.
ΔV (ΔV) between the peak hold voltage value of the second pulse and the second pulse.
= V ₂ −V ₁ ) and a pulse width.

FIG. 4 is a block diagram showing a circuit configuration according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a constant current pulse generation circuit according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Constant current drive means 3 Battery terminal voltage detection means at the time of charge 4 Circuit system 31 Constant current drive unit 32 Pulse generation unit 33 Secondary battery under test 34 Voltage measurement unit 35 Peak hold circuit 36 Calculation / judgment unit 37 Constant current pulse generation means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Nakauchigi 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Toshiro Hirai 3-19, Nishishinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation F term (reference) 2G016 CB05 CB06 CB21 CB25 CB31 CC01 CC04 CC09 CC15 CC19 CD02 5G003 BA01 CA02 CA18 CB07 CC07 EA08 5H030 AA06 AA10 AS20 FF43 FF44 FF52

Claims (9)

[Claims] 1. A method for judging deterioration of a secondary battery, wherein the first and second batteries having different durations within a transient time immediately after the start of charging and / or discharging of the secondary battery.
And determining the battery deterioration by calculating the peak hold voltage of the detected voltage for the first and second pulses. 2. The method according to claim 1, wherein the magnitude of the difference between the peak hold voltages corresponding to the pulse widths of the first and second pulses corresponds to the magnitude of the degradation. A method for determining deterioration of a secondary battery. 3. The method according to claim 1, wherein the difference between the voltage value corresponding to the first pulse and the magnitude of the difference between the peak hold voltages corresponding to the first and second pulses, respectively. A method for determining deterioration of a secondary battery, comprising determining deterioration by combining information. 4. The method for determining deterioration of a secondary battery according to claim 1, wherein a second pulse having a pulse width longer than the pulse width of the first pulse is provided, and then at least the second pulse width is provided. A longer third pulse, or a third pulse followed by a plurality of fourth or more constant current pulses, is sequentially applied, and the corresponding peak hold voltage is calculated to determine battery deterioration. A method for determining the deterioration of a secondary battery. 5. The method for determining deterioration of a secondary battery according to claim 1, wherein the first pulse width per cell is from 1 msec to 10 to several tens msec, and at least the second pulse width is at least 2 msec. A method for determining deterioration of a secondary battery, wherein the method is longer than a pulse width of the first pulse and not longer than 1 second, preferably not longer than 100 msec. 6. The method for determining deterioration of a secondary battery according to claim 4, wherein the first, second, and third driving devices are driven.
A method for determining deterioration of a secondary battery, wherein the constant current having a pulse width of a subsequent pulse is a charging and / or discharging current. 7. The method for determining deterioration of a secondary battery according to claim 4, wherein the first to third or third or more driven pulses are replaced with first to third constant currents having a pulse width. Or a constant voltage having a pulse width greater than or equal to the pulse width, and calculating the peak hold value of the charge or discharge current flowing through the battery to determine the deterioration of the secondary battery. 8. The first battery having a different duration within a transient phenomenon time immediately after the start of charging and / or discharging of the secondary battery.
Means for flowing two constant current pulses, means for measuring the voltage across the secondary battery when the constant current pulse is flowed by this means, and means for measuring the voltage across the secondary battery measured by this means. A peak hold circuit for detecting a peak hold voltage, and a first and a second signal detected by the peak hold circuit.
An apparatus for determining deterioration of a secondary battery, comprising: means for calculating a peak hold voltage of two constant current pulses; and means for determining deterioration of a secondary battery based on the calculation result calculated by the means. 9. The first battery having a different duration within a transient phenomenon time immediately after the start of charging and / or discharging of the secondary battery.
Means for applying two constant voltage pulses, means for measuring a current flowing through the secondary battery when the constant voltage pulse is applied by the means, and detecting a peak hold current of the current measured by the means. A peak hold circuit, and first and second 2
A deterioration determination device for a secondary battery, comprising: means for calculating a peak hold current of two constant voltage pulses; and means for determining deterioration of the secondary battery based on a calculation result calculated by the means.