JP3171581B2 - Battery pass / fail determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery quality judgment device.

[0002]

2. Description of the Related Art As a method of knowing whether a secondary battery (that is, a rechargeable battery) is good or not (that is, whether or not it has a normal charge / discharge capability), after the secondary battery is fully charged, a voltage between both ends of the secondary battery is obtained. There is known a method of determining pass / fail based on the length of the discharge time required for the voltage to decrease to a predetermined value.

[0003]

However, in the above-described method of determining the quality of a secondary battery based on the length of discharge time after full charge, the secondary battery to be determined is discharged for a long time. It needs to be done. Also, the relationship between the amount of charge discharged by the secondary battery and the voltage across the secondary battery is complicated,
Also, the relationship between the amount of charge discharged per unit time and the voltage across the secondary battery is complicated.

Therefore, in order to determine the quality of the secondary battery based on the length of the discharge time, it is necessary to continuously monitor the change in the amount of charge discharged per unit time. The configuration of the device that enables the above is complicated. Further, it is not easy to specify the length of discharge time of a secondary battery having a normal charge / discharge capability.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a battery pass / fail determination device that can easily determine pass / fail of a secondary battery in a short time.

[0006]

In order to achieve the above object, a battery quality discriminating apparatus according to the present invention comprises a battery including a DC current component and an AC current component between both poles of a secondary battery having both a positive pole and a negative pole. Pulsating current applying means for flowing a flowing current, AC voltage extracting means for extracting an AC voltage component included in a voltage generated between both poles of the secondary battery, and an AC voltage component extracted by the AC voltage extracting means. Determining whether or not the secondary battery is abnormal according to the size, and outputting information representing the determination result, wherein the pulsating flow applying unit includes a bipolar unit for each of the plurality of secondary batteries. In the meantime, the plurality of pulsating currents are caused to flow one-to-one, and the AC voltage extracting means
An AC voltage component included in a voltage generated between both poles of each of the secondary batteries is extracted, and the determining unit generates an average voltage representing an average value of the AC voltage components extracted by the AC voltage extracting unit. Means, the magnitude of each of the AC voltage components extracted by the AC voltage extraction means, to determine whether the difference between the value of the average voltage has reached a predetermined value, when it is determined that the difference has been reached, Means for determining that the secondary battery is abnormal.

In this case, the magnitude of the AC voltage component included in the voltage between the two electrodes of the secondary battery is determined depending on the impedance between the two electrodes of the secondary battery. Therefore, according to such a battery quality determination device, the quality of the secondary battery is determined based on the impedance between both electrodes of the secondary battery. Therefore, the quality of the secondary battery can be easily determined in a short time without measuring the discharge time of the secondary battery.

[0008]

[0009]

[0010]

The determination means includes means for generating an average voltage representing an average value of each AC voltage component extracted by the AC voltage extraction means, a magnitude of each AC voltage component extracted by the AC voltage extraction means, the difference between the value of the average voltage to determine whether or not reach the predetermined value, when it is determined to have reached, so and means for the secondary battery is judged to be abnormal, a plurality of two Of the following batteries, those having particularly poor charge / discharge capability are identified and determined to be abnormal.

The pulsating current applying means includes, for example, a rectifying means for rectifying a single-phase alternating current and outputting a current obtained by the rectification, thereby generating a pulsating current for flowing to the secondary battery. In this case, the battery quality determination means may include a means for flowing the current output by the rectification means between the two electrodes of the secondary battery.

[0013]

[0014]

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
A charger for charging a secondary battery will be described as an example with reference to the drawings. (First Embodiment) FIG. 1 is a circuit diagram showing a configuration of a charger according to a first embodiment of the present invention. As shown, the charger comprises a rectifier RECT1, a capacitor C1, a differential amplifier AMP1, and a light emitting diode L
It is composed of an ED1 and a load Z1.

The rectifier RECT1 is composed of, for example, a bridge-type full-wave rectifier circuit, and has an input terminal having two poles and an output terminal having a positive electrode and a negative electrode. The positive electrode of the secondary battery B to be charged is connected to the positive electrode of the output terminal of the rectifier RECT1, and the negative electrode of the secondary battery B is connected to the rectifier RE.
It is connected to the negative terminal of the output terminal of CT1. The rectifier RE
The input of CT1 is the power input of this charger.

When a single-phase AC voltage is applied between the two poles of the input terminal, the rectifier RECT1 generates a pulsating voltage obtained by full-wave rectification of the single-phase AC voltage between the two poles of the output terminal. . However, the rectifier RECT1 generates a pulsating voltage such that the voltage of the positive electrode of the output terminal becomes 0 volt or more with reference to the potential of the negative electrode of the output terminal.

The capacitor C1 is connected between the positive terminal of the output terminal of the rectifier RECT1 and the non-inverting input terminal of the differential amplifier AMP1. The capacitor C1 passes an AC component included in a voltage applied to one end of the capacitor C1 to the other end.

The differential amplifier AMP1 is composed of an operational amplifier and the like, and has a non-inverting input terminal, an inverting input terminal, and an output terminal. The differential amplifier AMP1 generates at the output terminal a voltage substantially proportional to the voltage at the non-inverting input terminal with reference to the potential at the inverting input terminal.

The light emitting diode LED1 has an anode and a cathode. The light-emitting diode LED1 is connected in cascade with the load Z1 to form a series circuit.
One of the terminals near the anode is connected to the output terminal of the differential amplifier AMP1, and the other terminal is connected to the negative terminal of the output terminal of the rectifier RECT1.

When a single-phase AC voltage is applied between both terminals of the power input terminal of the charger, the positive terminal of the output terminal of the rectifier RECT1 has a positive polarity with respect to the negative terminal between the two terminals of the output terminal of the rectifier RECT1. A pulsating voltage in an appropriate direction is generated. Then, the pulsating voltage generated by the rectifier RECT1 is applied between the two poles of the secondary battery B. The secondary battery B is charged while the instantaneous value of the voltage of the pulsating current has reached a voltage at which the secondary battery B is charged.

At this time, the magnitude of the AC component included in the voltage generated between the two poles of the secondary battery B depends on the rectifier RECT1.
The value depends on the output impedance between the two electrodes at the output end of the secondary battery B and the impedance between the two electrodes of the secondary battery B.

The AC component included in the voltage generated at the positive electrode of the secondary battery B passes through the capacitor C1 and is applied to the non-inverting input terminal of the differential amplifier AMP1. Also,
The potential at the inverting input terminal of the differential amplifier AMP1 is
Is substantially the same as the potential of the negative electrode. Therefore, when the potential at the inverting input terminal of the differential amplifier AMP1 is used as a reference, the value of the voltage at the non-inverting input terminal of the differential amplifier AMP1 is substantially equal to the value of the AC component of the positive electrode voltage of the secondary battery B. Become equal.

As a result, a voltage having a magnitude substantially proportional to the AC component of the positive electrode voltage with respect to the negative electrode of the secondary battery B is generated at the output terminal of the differential amplifier AMP1. The output terminal of the differential amplifier AMP1 and the rectifier RECT1
The voltage between the negative terminal of the output terminal of the
1 and the load Z1 are applied between both ends of a series circuit formed by the load.

As a result of applying an AC voltage across the series circuit formed by the light emitting diode LED1 and the load Z1,
The light emitting diode LED1 conducts and emits light when it is forward biased (specifically, for example, when the voltage of the anode of the light emitting diode LED1 becomes higher than the potential of the cathode by about 0.6 V or more). .

When the voltage between the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1 has any value, the light emitting diode L
Whether the ED1 is forward-biased depends on the amplification factor of the differential amplifier AMP1 and the impedance of the load Z1. On the other hand, a secondary battery has a property that when a current including an AC component flows between both electrodes in a state where the charge / discharge capacity is normal, the amplitude of the AC component of a voltage generated between the two electrodes becomes equal to or less than a certain value. Have.

Therefore, the amplification factor of the differential amplifier AMP1
By appropriately selecting the impedance of the load Z1, the light emitting diode LED1 emits light when the rechargeable battery B whose charging / discharging ability is not normal is applied with a pulsating voltage.

For example, when the rechargeable battery B has a normal charging / discharging ability, the AC component of the voltage generated between both electrodes is 10%.
Assume that it is less than millivolt. In this case, the differential amplifier A
When the voltage between the non-inverting input terminals of MP1 reaches 10 millivolts with respect to the potential of the inverting input terminal, the differential amplifier AMP1 is forward-biased so that the light emitting diode LED1 is forward-biased.
Is selected, and the impedance of the load Z1 is selected, the light emitting diode LED1 does not emit light when the secondary battery B is normal.

On the other hand, when at least one of the two electrodes of the secondary battery B is no longer in contact with the electrolyte filling the gap between the two electrodes (for example, when the secondary battery B is constituted by a lead storage battery, any one of the secondary batteries B Is no longer in direct contact with the dilute sulfuric acid that fills the space between the positive and negative electrodes), and the resistance between the two electrodes of the secondary battery B is lower than when the secondary battery B is normal. Increase. Therefore, in this case, the rectifier RECT
The amplitude of the DC component and the AC component of the voltage between the two electrodes of the secondary battery B to which the voltage of the pulsating current between the two electrodes at the output terminal 1 is applied is smaller than that in the case where the secondary battery B is normal. The light emitting diode LED1 emits light.

The configuration of the charger is not limited to the above. For example, when the AC component of the voltage between both ends of the secondary battery B is equal to or more than a certain value (that is, the voltage at the output terminal of the differential amplifier AMP1 is a value sufficient to forward bias the light emitting diode LED1). ), The supply of the pulsating flow to the secondary battery B may be cut off.

Specifically, the charger includes, for example, a relay circuit including a current path connected between one of the input terminals of the rectifier RECT1 and one of the poles of the single-phase alternating current supply source. This relay circuit is a differential amplifier AM
It is sufficient to detect that the voltage at the output terminal of P1 has reached a value sufficient to forward bias the light emitting diode LED1, and to interrupt its own current path.

The method of indicating by the charger whether or not the AC component of the voltage between both ends of the secondary battery B is equal to or less than a predetermined value is arbitrary, and it is not necessary to indicate whether or not the light emitting diode LED1 emits light. . Therefore, this charger uses the secondary battery B
The presence or absence of a sound may indicate whether or not the AC component of the voltage between both ends is equal to or less than a predetermined value. In this case, the charger includes, for example, the output terminal of the differential amplifier AMP1 and the secondary battery B.
And a buzzer or the like connected between the negative electrode and the negative electrode.

When the secondary battery B is in a dendrite short state (that is, as a result of the reduction of the metal ions in the electrolyte filling between the electrodes of the secondary battery B by charging or the like, a dendritic metal When the crystal grows and short-circuits between the two electrodes), the resistance value between the two electrodes of the secondary battery B is lower than when the secondary battery B is normal. Therefore, in this case, the amplitude of the DC component and the alternating current component of the voltage between the two electrodes of the secondary battery B to which the voltage of the pulsating current generated between the two electrodes at the output terminal of the rectifier RECT1 is both The light emitting diode LED1 does not emit light because the light emitting diode LED1 decreases in comparison with the normal case.

However, abnormalities in which the resistance between the two electrodes of the secondary battery B decreases, such as dendrite short-circuit of the secondary battery B, are as follows.
It can be detected by monitoring the DC component of the voltage between the two electrodes of the secondary battery B. Specifically, for example, FIG.
As shown in FIG. 1, in addition to the configuration shown in FIG. 1, this charger further includes a low-pass filter LPF
1, a comparator CMP, and a light emitting diode LED2
And a load Z2.

The low-pass filter LPF has an input terminal and an output terminal, and generates, at its own output terminal, a voltage corresponding to a component obtained by substantially removing an AC component among voltages applied to its own input terminal. The input terminal of the low-pass filter LPF is connected to the positive electrode of the secondary battery B, and the output terminal is connected to a later-described non-inverting input terminal of the comparator CMP.

The reference voltage source REF1 is constituted by a known constant voltage source or the like, and the secondary battery B when the voltage at the output terminal of the rectifier RECT1 is applied between both poles of the normal secondary battery B. And generates a voltage substantially equal to the lowest value of the DC component of the voltage between both electrodes of the comparator CMP, and applies it to an inverting input terminal of the comparator CMP, which will be described later.

The comparator CMP has an inverting input terminal, a non-inverting input terminal, and an output terminal. When the non-inverting input terminal has a higher potential than the inverting input terminal, the comparator CMP has a positive polarity with reference to the negative potential of the output terminal of the rectifier RECT1. Voltage at the output end,
At other times, it produces a voltage of about 0 volts.

The light emitting diode LED2 has an anode and a cathode, and is connected in cascade with a load Z2 composed of a resistor or the like to form a series circuit. Of both ends of the series circuit, the end is close to the anode of the light emitting diode LED2. One end is connected to the output terminal of the comparator CMP, and the other end is connected to the negative terminal of the output terminal of the rectifier RECT1. The impedance of the load Z2 is selected to be a value such that when the output terminal of the comparator CMP generates a positive voltage with reference to the potential of the output terminal of the rectifier RECT1, the light emitting diode LED2 is forward-biased and emits light. I have.

In the charger having the configuration shown in FIG. 2, the DC component of the voltage of the positive electrode of the secondary battery B is converted to a low-pass filter LPF.
To the non-inverting input terminal of the comparator CMP. The value of the DC component of the voltage between the two electrodes of the secondary battery B is the voltage between the two electrodes of the secondary battery B when the voltage of the output terminal of the rectifier RECT1 is applied between the two electrodes of the normal secondary battery B. When the DC component value exceeds the minimum value, the comparator CM
The non-inverting input terminal of P has a higher potential than the inverting input terminal of the comparator CMP. Therefore, a positive voltage is generated at the output terminal of the comparator CMP with reference to the potential of the output terminal of the rectifier RECT1, and the light emitting diode LED2 emits light. On the other hand, the value of the DC component of the voltage between the two electrodes of the secondary battery B is the voltage between the two electrodes of the secondary battery B when the voltage of the output terminal of the rectifier RECT1 is applied between the two electrodes of the normal secondary battery B. When the DC component falls below the minimum value of the DC component, the light emitting diode LED2 does not emit light.

The AC component of the voltage between the two electrodes of the secondary battery B does not necessarily need to be directly applied between the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1. It may be applied after being converted. Specifically, this charger may have a configuration shown in FIG. 3, for example.

As shown, the charger of FIG. 3 includes a transformer T1 in addition to the configuration of FIG. The transformer T1 has a primary winding and a secondary winding, and one end of the primary winding is connected to a rectifier RE.
The other end of the capacitor C1 is connected to the other end of the capacitor C1 that is not connected to the positive end of the output end of the rectifier RECT1. Both ends of the secondary winding of the transformer T1 are connected one-to-one to the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1. Note that, in the configuration of FIG.
The other end not connected to the positive terminal of the differential amplifier AMP
1 is not connected. And the light emitting diode LE
The cathode of D1 and the inverting input terminal of the differential amplifier AMP1 are grounded. However, the ground to which the light emitting diode LED1 and the differential amplifier AMP1 are connected is connected to the primary winding of the transformer T1, the rectifier RECT1,
It is substantially insulated from the secondary battery B and the capacitor C1.

In the configuration of FIG. 3, the AC component of the voltage between the two electrodes of the secondary battery B is transformed by the transformer T1, and then applied between the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1. Is done. For this reason, the magnitude of the AC component of the voltage between the two electrodes of the secondary battery B exceeds the rated input voltage which is the upper limit that can be applied between the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1, and this AC component Is applied between the inverting input terminal and the non-inverting input terminal of the differential amplifier AMP1 and the differential amplifier AMP1 may be destroyed. It becomes possible.
Also, in the configuration of FIG. 3, the secondary winding of the transformer T1,
Differential amplifier AMP1, load Z1, and light emitting diode LE
D1 is substantially isolated from the primary winding of transformer T1, rectifier RECT1, secondary battery B and capacitor C1.

When the AC component of the voltage between the two electrodes of the secondary battery B is applied to the differential amplifier AMP1, the differential amplifier A
As a case where the risk of exceeding the rated input voltage of the inverting input terminal or the non-inverting input terminal of MP1 is large, for example, the secondary battery B
May be composed of a plurality of secondary batteries connected in cascade. Therefore, the charger having the configuration shown in FIG. 3 is suitable for performing the operation of judging the quality of the plurality of secondary batteries while simultaneously charging the plurality of secondary batteries connected in cascade.

(Second Embodiment) FIG. 4 is a circuit diagram showing a configuration of a charger according to a second embodiment of the present invention. As shown, this charger comprises a rectifier RECT
It comprises two, n (where n is an arbitrary positive integer) ripple detection units DET1 to DETn, and a capacitor C4.

The rectifier RECT2 includes, for example, a number n of full-wave rectifier circuits for rectifying the voltage supplied thereto, a primary winding and n secondary windings, and a voltage between both ends of each secondary winding. And a transformer for supplying each one-to-one to each full-wave rectifier circuit. The rectifier RECT2 has an input terminal IN having two poles, and n sets of output terminals OUT1 to OUTn each having a positive electrode and a negative electrode.

The input terminal IN of the rectifier RECT2 forms the power input terminal of the charger. Secondary battery Bk to be charged
The positive electrode (where k is an integer of 1 to n) is connected to the positive electrode of the output terminal OUTk of the rectifier RECT2, and the negative electrode of the secondary battery Bk is connected to the negative electrode of the output terminal OUTk of the rectifier RECT2.

When a single-phase AC voltage is applied between the two terminals of the input terminal IN, the rectifier RECT2 outputs a pulsating voltage obtained by full-wave rectification of the single-phase AC voltage between the two terminals of the output terminal OUTk. generate. However, the rectifier RECT2 is connected to the output terminal OUTk with reference to the negative potential of the output terminal OUTk.
A pulsating voltage is generated so that the voltage of the positive electrode of k becomes 0 volt or more.

The ripple detectors DET1 to DETn have substantially the same configuration as each other, and
Tk (k is an integer of 1 or more and n or less) is a differential amplifier AMP
2k, capacitors C2k and C3k, and transformer T2k
, A diode D1k, a resistor Rk, and a load Z3k.
And a light emitting diode LED3k.

The capacitor C2k is substantially the same as the capacitor C1 in the first embodiment. The positive terminal of the output terminal OUTk of the rectifier RECT2 and the transformer T2
k and one end of a primary winding described later.

The transformer T2k is, for example, the transformer T1 described above.
Are substantially the same. One end of the primary winding of the transformer T2k is connected to the negative electrode of the output terminal OUTk of the rectifier RECT2, and the other end is connected to the rectifier RE
The output terminal OUTk of CT2 is connected to the other end that is not connected to the positive electrode. One end of the secondary winding of the transformer T2k is connected to an anode of the diode D1k described later, and the other end is grounded.

The diode D1k has an anode and a cathode, and the anode of the diode D1k is, as described above,
It is connected to the non-grounded end of the secondary winding of the transformer T2k. The cathode of the diode D1k is connected to the non-inverting input terminal of the differential amplifier AMP2k substantially the same as the differential amplifier AMP1 in the first embodiment.

The capacitor C3k is for smoothing the voltage between the cathode of the diode D1k and the ground. One end of the capacitor C3k is connected to a diode D1.
k, and the other end is grounded.

The resistor Rk includes diodes D11 to D1n.
For generating a voltage corresponding to the average value of the voltages generated at the cathodes. One end of the resistor Rk is connected to the non-inverting input terminal of the differential amplifier AMP2k, and the other end is connected to the inverting input terminal of the differential amplifier AMP2k.

The light emitting diode LED3k is substantially the same as the light emitting diode LED1 in the first embodiment, and is connected in cascade with the load Z3k to form a series circuit. Of the two ends of the series circuit, the end near the anode of the light emitting diode LED3k is connected to the output terminal of the differential amplifier AMP2k, and the other end is grounded.

The capacitances of the capacitors C31 to C3n are substantially equal to each other, and the resistance values of the resistors R1 to Rn are also substantially equal to each other.

The capacitor C4 includes diodes D11 to D11.
This is for smoothing the voltage corresponding to the average value of the voltage generated at the 1n cathode. One end of the capacitor C4 is commonly connected to the inverting amplifiers of the differential amplifiers AMP21 to AMP2n, and the other end is grounded.

When a single-phase AC voltage is applied between both terminals of the power supply input terminal IN of this charger, the output terminal O of the rectifier RECT2 is
Between the two poles of UTk, the positive pole of the output terminal OUTk is connected to the output terminal O.
A pulsating voltage is generated that has a positive polarity with respect to the negative electrode of UTk. The voltage of the pulsating current generated between the two electrodes of the output terminal OUTk is applied between the two electrodes of the secondary battery Bk, and the instantaneous value of the voltage of the pulsating current reaches a voltage at which the secondary battery Bk is charged. During this time, the secondary battery Bk is charged.

As a result, a voltage having a value dependent on the output impedance between the two electrodes of the output terminal OUTk of the rectifier RECT2 and the impedance between the two electrodes of the secondary battery Bk is generated between the two electrodes of the secondary battery Bk. The AC component of the voltage passes through capacitor C2k and is applied across the primary winding of transformer T2k.

Then, a voltage which is substantially proportional to the voltage between both ends of the primary winding of the transformer T2k is generated between both ends of the secondary winding of the transformer T2k. As a result of half-wave rectification of the voltage between both ends of the secondary winding of the device T2k, a voltage corresponding to a result smoothed by the capacitor C3k is generated. Then, the voltage of the cathode of the diode D1k is applied to the non-inverting input terminal of the differential amplifier AMP2k.

On the other hand, the potential at the inverting input terminal of the differential amplifier AMP2k is substantially equal to the average value of the voltages at the cathodes of the diodes D11 to D1n (ie, the voltages at the non-inverting input terminals of the differential amplifiers AMP21 to AMP2n). Is equal to
Therefore, the value of the voltage at the output terminal of the differential amplifier AMP2k is
The average value of the values obtained by half-wave rectifying and smoothing the AC components of the positive electrode voltages of the secondary batteries B1 to Bn from the values obtained by half-wave rectifying and smoothing the AC components of the positive electrode voltage of the secondary battery Bk. Is substantially proportional to the value obtained by subtracting. Then, the voltage at the output terminal of the differential amplifier AMP2k is applied across the series circuit formed by the light emitting diode LED3k and the load Z3k.

For this reason, by appropriately selecting the amplification factor of the differential amplifier AMP2k and the impedance of the load Z3k, the light emitting diode LED3k can be connected to the secondary battery Bk.
The magnitude of the AC component of the voltage between both ends of the secondary battery B1
Light is emitted when the average value of the AC component of the voltage between both ends of Bn exceeds a certain value or more. Then, assuming that the smaller the value of the AC component of the voltage between both ends of the secondary battery Bk is, the higher the charging / discharging ability of the secondary battery Bk is, the light emitting diode LED3k eventually ends up charging / discharging the secondary battery Bk. It means that light is emitted when the capacity is lower than the average of the charge and discharge capacities between both ends of the secondary batteries B1 to Bn by a certain degree or more.

The configuration of the charger according to this embodiment is not limited to the above-described one.
DETn is a low-pass filter L shown in FIG.
It may include substantially the same components as the PF, the reference voltage source REF1, the comparator CMP, the light emitting diode LED2, and the load Z2. However, the input terminal of the low-pass filter LPF of the ripple detection unit DETk is connected to the positive electrode of the secondary battery Bk, and the light emitting diode L of the ripple detection unit DETk is
Of the two ends of the series circuit formed by the ED2 and the load Z2,
The end closer to the cathode of the light emitting diode LED2 is connected to the negative terminal of the output terminal OUTk of the rectifier RECT2. Further, the reference voltage source R of the ripple detection unit DETk
EF1 has a rectifier REC between both poles of a normal secondary battery Bk.
It is assumed that a voltage substantially equal to the minimum value of the DC component of the voltage between both electrodes of the secondary battery Bk when the voltage of the output terminal OUTk of T2 is applied. In this case, the secondary battery B
When the value of the DC component of the voltage between both poles of the first and second electrodes k is equal to or greater than the minimum value, the light emitting diode LED2
Emits light.

(Third Embodiment) FIG. 5 is a circuit diagram showing a configuration of a charger according to a third embodiment of the present invention. As shown, the charger comprises a diode D2
And D3, a capacitor C5, a transformer T3, a differential amplifier AMP3, a reference voltage source REF2, a light emitting diode LED4, a load Z4, a trigger generator TRG, a transistor Q, and a DC power source E. Have been.

Each of the diodes D2 and D3 has an anode and a cathode. The anode of the diode D2 is connected to one end of a primary winding described later of the transformer T3, and the cathode is connected to the non-inverting input terminal of the differential amplifier AMP3. The differential amplifier AMP3 is substantially the same as that in the first embodiment. The anode of the diode D3 is connected to one end of a later-described secondary winding of the transformer T3, and the cathode is connected to the positive electrode of the secondary battery B to be charged.

However, the end to which the anodes of the diodes D2 and D3 are connected is connected to the anode of the diode D2 among the both ends of the primary winding of the transformer T3 when a current flows through the primary winding of the transformer T3. The polarity of the voltage with respect to the other end of the connected end is the same as the polarity of the voltage with respect to the other end of the end of the secondary winding of the transformer T3 to which the anode of the diode D3 is connected. It is assumed that they are chosen to be

The transformer T3 has a primary winding and a secondary winding. One end of the primary winding of the transformer T3 is connected to the anode of the diode D2 as described above, and the other end is grounded. One end of the secondary winding of the transformer T3 is connected to the anode of the diode D3 as described above, and the other end is connected to the negative electrode of the secondary battery B.

The capacitor C5 is for smoothing the voltage between the cathode of the diode D2 and the ground. One end of the capacitor C5 is connected to the cathode of the diode D2, and the other end is grounded.

The reference voltage source REF2 is composed of a constant voltage source having a known configuration, generates a predetermined reference voltage, and applies it to the inverting input terminal of the differential amplifier AMP3.

The trigger generator TRG is composed of an oscillator or the like that generates a rectangular wave, has an output terminal having a pair of poles, and generates a rectangular wave between both the output terminals. However, the amplitude of this rectangular wave is equal to or greater than the minimum value of the voltage that needs to be applied between the base and the emitter of the transistor Q described later to turn on the transistor Q. One pole of the output terminal of the trigger generator TRG is connected to a base of the transistor Q described later, and the other pole is connected to an emitter of the transistor Q described later.

The DC power supply E has an output terminal provided with a positive electrode and a negative electrode, and generates a DC voltage between both electrodes of its own output terminal such that the positive electrode has a positive polarity with respect to the negative electrode.

The transistor Q is formed of an NPN type bipolar transistor and has a base, an emitter and a collector. As described above, the base and the emitter of the transistor Q are connected to each pole of the output terminal of the trigger generator TRG by one.
They are connected one to one. Further, a current path having both ends of the collector and the emitter of the transistor Q and the DC power supply E are connected in cascade to form a DC circuit. However, the current path and the DC power supply E are connected such that, when the collector-emitter of the transistor Q conducts, one end of the DC circuit closer to the emitter of the transistor Q has a positive polarity. . The end of the series circuit formed by the transistor Q and the DC power supply E, which is closer to the negative electrode of the DC power supply E, is connected to the anode of the diode D2, and the other end is grounded.

The light emitting diode LED4 is substantially the same as the light emitting diode LED1 in the first embodiment, and is connected in cascade with the load Z4 to form a series circuit. Then, of the two ends of this series circuit formed by the light emitting diode LED4 and the load Z4, the end closer to the anode of the light emitting diode LED4 is connected to the output terminal of the differential amplifier AMP3, and the other end is grounded. .

When a rectangular wave is generated at the output terminal of the trigger generator TRG of the charger, the rectangular wave is applied between the base and the emitter of the transistor Q. Then, during a period in which the base of the transistor Q is at a higher potential than the emitter due to the rectangular wave, the transistor Q is turned on.

During the period in which the transistor Q is on, the transformer T3 is connected from the grounded end of the two ends of the series circuit formed by the transistor Q and the DC power supply E.
Current flows toward the primary winding of The transformer T3
Of the two ends of the primary winding connected to the diode D2 has a negative polarity with respect to the ground, so that the diode D2 is reverse-biased, so that current substantially flows through the diode D2. Absent. On the other hand, the transformer T3
The electromotive force is also induced in the secondary winding of the transformer T3 by the current flowing through the primary winding of the transformer T3. However, this electromotive force is such that, of the two ends of the secondary winding, the end connected to the diode D3 has a lower potential than the other end. Accordingly, the diode D3 is also reverse-biased, and the path through which current is supplied from the secondary winding of the transformer T3 to the secondary battery B is substantially cut off.

Next, when the base of the transistor Q becomes lower in potential than the emitter due to the rectangular wave generated by the trigger generator TRG, the transistor Q is turned off, and the current is supplied from the DC power supply E to the primary winding of the transformer T3. Virtually refused.

Then, a back electromotive force is generated in the primary winding of the transformer T3, and one end of the primary winding connected to the diode D2 has a positive polarity. As a result, the diode D2 is forward-biased, and the non-inverting input terminal of the differential amplifier AMP3 has a value obtained by substantially integrating the voltage of the anode of the diode D2 to which the primary winding of the transformer T3 is connected by the capacitor C5. Is supplied.

On the other hand, the current flowing in the primary winding due to the back electromotive force generated in the primary winding of the transformer T3 induces an electromotive force in the secondary winding of the transformer T3 in a direction to forward bias the diode D3. . The difference between the magnitude of the electromotive force generated in the secondary winding and the voltage between the two electrodes of the secondary battery B is the diode D
3, the diode D3 is forward biased and the secondary winding of the transformer T3
Then, a current flows into the positive electrode of the secondary battery B via 3. The secondary battery B is charged by this current.

The magnitude of the current flowing into the secondary battery B due to the electromotive force generated in the secondary winding of the transformer T3 is
The value depends on the magnitude and rate of change of the electromotive force generated in the secondary winding and the impedance between the two electrodes of the secondary battery B. Therefore, under the condition that the magnitude and the rate of change of the electromotive force generated in the secondary winding of the transformer T3 are the same, the current flowing into the positive electrode of the secondary battery B decreases as the impedance between the two electrodes of the secondary battery B decreases. Becomes larger.

On the other hand, the product of the magnitude of the electromotive force generated across the primary winding of the transformer T3 and the magnitude of the current flowing through the primary winding is the electromotive force generated across the secondary winding of the transformer T3. And the magnitude of the current flowing through the secondary winding. For this reason, the larger the current flowing from the secondary winding of the transformer T3 to the secondary battery B, the smaller the current flowing from the primary winding of the transformer T3 to the anode of the diode D2, and therefore, from the cathode of the diode D2. The current flowing into the capacitor C5 also decreases. As a result, the larger the current flowing from the secondary winding of the transformer T3 to the secondary battery B is, the more the capacitor C is turned off while the transistor Q is off.
5, the maximum value at which the voltage between both ends reaches is reduced.

The output terminal of the differential amplifier AMP3 has a voltage proportional to the voltage of the non-inverting input terminal with respect to the potential of the inverting input terminal of the differential amplifier AMP3,
That is, a voltage having a magnitude substantially proportional to a value obtained by subtracting the reference voltage generated by the reference voltage source REF2 from the voltage between both ends of the capacitor C5 is generated.

Therefore, the amplification factor of the differential amplifier AMP3
By appropriately selecting the voltage at the output terminal of the reference voltage source REF2 and the impedance of the load Z4, the light emitting diode LED4 can be used to charge or discharge the secondary battery B having an abnormal charge / discharge capacity.
Emits light when a pulsating voltage is applied.

The configuration of the charger of this embodiment is not limited to the above-described configuration.
Type bipolar transistors and enhancement type MO
SFET (Metal-Oxide-Silicon Field Effect Transis
tor). When the transistor Q is composed of an enhancement-type MOSFET, the gate, source and drain of the enhancement-type MOSFET are sequentially connected to locations where the base, emitter and collector of the transistor Q are to be connected in the configuration of FIG. What should I do?

[0083]

As described above, according to the present invention, there is provided a battery quality determining apparatus which can easily determine the quality of a secondary battery in a short time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a charger according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a modification of the charger of FIG.

FIG. 3 is a circuit diagram showing a configuration of a modification of the charger of FIG.

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

FIG. 5 is a circuit diagram showing a configuration of a charger according to a third embodiment of the present invention.

[Explanation of symbols]

AMP1, AMP21-AMP2n, AMP3
Differential amplifier B, B1 to Bn
Secondary batteries C1, C21 to C2n, C31 to C3n, C4, C5
Capacitor CMP
Comparators D11 to D1n, D2, D3
Diodes DET1 to DETn
Ripple detector E
DC power supply LED1, LED2, LED31-LED3n, LED
4 Light emitting diode LPF
Low-pass filter Q
Transistors R1 to Rn
Resistors RECT1, RECT2
Rectifier REF1, REF2
Reference voltage sources T1, T21 to T2n, T3
Transformer TRG
Trigger generator Z1, Z2, Z31 to Z3n, Z4
load

Claims (2)

(57) [Claims] 1. A pulsating flow applying means for flowing a pulsating current including a direct current component and an alternating current component between two poles of a secondary battery having both a positive electrode and a negative electrode; AC voltage extraction means for extracting an AC voltage component included in the voltage, and according to the magnitude of the AC voltage component extracted by the AC voltage extraction means, to determine whether the secondary battery is abnormal, Determining means for outputting information indicating a determination result, wherein the pulsating current applying means causes the plurality of pulsating currents to flow in a one-to-one manner between the respective poles of the plurality of secondary batteries, and the AC voltage extraction Means for extracting an AC voltage component included in a voltage generated between both poles of each of the secondary batteries; and the determining means, an average voltage representing an average value of the AC voltage components extracted by the AC voltage extracting means. Generating means; and the AC voltage extracting means. It is determined whether or not the difference between the magnitude of each extracted AC voltage component and the value of the average voltage has reached a predetermined value, and when it is determined that the difference has been reached, the secondary battery is abnormal. Means for determining the quality of the battery. 2. The pulsating flow applying means rectifies a single-phase AC current and outputs a current obtained by the rectification; and a means for flowing the current output by the rectifying means between both poles of the secondary battery. The battery quality judgment device according to claim 1, comprising: