JP2905581B2 - Charging device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charging device for a rechargeable battery device having, for example, a non-aqueous secondary battery, and more particularly to a charging device capable of quick charging.

[Conventional technology]

With the development of portable devices, primary batteries and secondary batteries are used as power sources for radios, cassette tape recorders with radios, portable VTRs, electronic devices such as portable computers, communication devices such as mobile phones, and power devices such as portable electric tools. Batteries are becoming widely used. In particular, the use of secondary batteries has increased remarkably in recent years.

In particular, in portable equipment, there is a growing demand for a light-weight, small-sized, high-capacity rechargeable battery device capable of quick charging, and non-aqueous secondary batteries have recently been receiving attention. At the same time, in portable devices, it is desired to reduce the size of the quick charging device. By the way, in a non-aqueous secondary battery which is not preferable in terms of safety when the voltage between terminals becomes a certain voltage or more,
Charge current limited type constant voltage charge, or constant current charge type constant voltage charge by extending the constant current charge time by converting the charge amount in constant voltage charge from the charge time to constant voltage charge voltage in constant current charge A charging method of stopping charging at a charge amount corresponding to the above has been taken.

Conventionally, in a non-aqueous rechargeable battery device in which charging current limiting type constant voltage charging is performed, when charging is to be rapidly performed, a method of loosening the charging current limit and increasing the charging current to shorten the charging time. Is usually taken. In the charging current-limited type constant-voltage charging, constant-current charging or quasi-constant-current charging is performed until the charging reaches the constant-voltage charging. After reaching the constant-voltage charging, the charging current increases as the charging proceeds. The charging is monotonously reduced, and the charging is completed while the charging current approaches zero.

[Problems to be solved by the invention]

However, in the method of loosening the limit of the charging current and increasing the charging current to shorten the charging time, it is necessary to increase the current rating of the charging device with an increase in the maximum charging current value. Not only did the size of the device increase, but the charging time did not become much shorter than the rate of increase in the maximum charging current value. In other words, the time for constant current charging or quasi-constant current charging is reduced with an increase in the maximum charging current value, but the charging time after reaching the constant voltage is rather extended, and as a result, the total charging time Is not much shorter than the rate of increase in the magnitude of the maximum charging current value.

Moreover, as the maximum charging current value increases, not only does the performance of the rechargeable battery device deteriorate, but also the safety of the battery device during charging decreases. That is, as the charging current increases, the heat generation inside the rechargeable battery device increases, and not only can the temperature rise of the rechargeable battery device not be ignored, but also if the constant current charging is continued for a long time while the charging is in progress. In some cases, the electrodes inside the battery are partially overcharged, which not only accelerates the deterioration of the performance of the battery but also leads to an unfavorable state in terms of safety.

In addition, the constant-current charging time is extended by converting the charging amount in the constant-voltage charging from the charging time to the constant-voltage charging voltage in the constant-current charging, and the charging is stopped at the charging amount equivalent to the charging current-limited type constant-voltage charging. In such a charging device, the variation in the internal resistance of the rechargeable battery device results in an excess or deficiency of the charged amount as it is, and it is difficult to control the charged amount to an appropriate amount.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a non-aqueous rechargeable battery using a material capable of intercalating cations into gaps of a molecular structure in one of a positive electrode and a negative electrode, or both a positive electrode and a negative electrode. In the battery device, a constant current or quasi-constant current power supply, switch means inserted in series in a charge / discharge circuit between the power supply and the rechargeable battery device, and voltage detection for detecting a terminal voltage of the rechargeable battery device Means, when the inter-terminal voltage at the start of charging is lower than the first voltage based on the detection result of the voltage detecting means, the switch means is continuously turned on, and the inter-terminal voltage is reduced to the first voltage. After reaching the voltage, the rechargeable battery device is pulse-charged by repeatedly turning on / off the switch means and continuing the charging current from the power supply,
Charge control means for terminating the pulse charging when the inter-terminal voltage when the pulse charging is off exceeds a second voltage higher than the first voltage.

That is, in the present invention, when charging a battery device that performs constant-current charging of a charging current limitation type, the constant-voltage charging portion after constant-current charging or quasi-constant-current charging is replaced with pulse charging to thereby perform constant-voltage charging. The time corresponding to the charging time required for charging can be significantly reduced, without thereby increasing the rated current of the charging device,
It has been found that the charging time can be significantly reduced. Especially,
In the case of charging with a large charging current, the effect of significantly shortening the charging time appears, and a high-performance rapid charging device can be provided.

Therefore, as a result of studying a method of controlling charging, the timing of transition from constant current charging or quasi-constant current charging to pulse charging is determined based on the voltage between terminals of the rechargeable battery device during constant current charging or quasi-constant current charging. It has been found that the timing of terminating the pulse charging is preferably determined by the terminal voltage of the rechargeable battery device when the charging current is off.

That is, when the voltage between terminals of the rechargeable battery device at the start of charging is lower than the first voltage (V _off ), constant current charging or quasi-constant current charging is performed. After the voltage between terminals of the rechargeable battery device reaches the first voltage (V _off ), pulse charging having an on-time (t _on ) of 1 μsec or more and 1 sec or less and an off-time (toff) of 1 μsec or more is performed. When the inter-terminal voltage of the rechargeable battery device at the time of the pulse charging is turned off is equal to or higher than a second voltage (V ^PC _off ) higher than the first voltage, the pulse charging is terminated, or the rechargeable battery at the start of the charging. When the voltage between terminals of the device is lower than the first voltage (V _off ), constant-current charging or quasi-constant-current charging is performed. 1 μse when the voltage exceeds the first voltage (V _off ) A pulse charge having an on time (t _on ) of not less than c and not more than 1 sec and an off time (t _off ) of not less than 1 μsec is performed. higher second voltage (V ^PC _off) above becomes once interrupted pulse charge, a second voltage terminal voltage of the rechargeable battery device again (V ^PC _off) lower than the third voltage (V ^PC _on) When the pulse charge becomes less than or equal to the above, the pulse charge is restarted, and when the voltage between the terminals of the rechargeable battery device at the time of turning _{off the} pulse charge becomes higher than or equal to the second voltage (V ^PC _off ), the pulse charge is temporarily interrupted. When the voltage between the terminals of the rechargeable battery device at the start of charging is lower than the first voltage (V _off ), constant-current charging or quasi-constant-current charging is performed. inter-terminal voltage of the battery device is a first voltage (V _off) or Comes to block the charging current after flowing predetermined on-time (t _on) or, again, at the first voltage (V _off) lower fourth voltage than (V _on) or less,
When the charging current is passed and the voltage between the terminals of the rechargeable battery device is equal to or higher than the first voltage (V _off ), the charging current is cut off after the predetermined ON time (t _on ) or more, and the constant current is repeated. After charging or semi-constant current charging, perform pulse charging in which the off-time (t _off ) changes according to the amount of charge. For example, increase the average charging current for pulse charging compared to the charging current for constant voltage charging. It was found that the charging time can be remarkably reduced as compared with the charging current limiting type constant voltage charging.

It is desirable that the on-time (t _on ) be fixed at 1 μsec or more and 1 sec or less. The off time (t _off ) does not necessarily have to be fixed, and it is sufficient that the measurement of the voltage between the terminals of the rechargeable battery device and the switching of the switch means can be performed during the interruption of the pulse current, but usually 1 μsec or more is required. Further, the duty ratio {Q = t _on / (t _on + t _off )} is 0 <Q
<1, but it is preferable to set the value as close to 1 as possible for the purpose of shortening the charging time. However, the duty ratio (Q) does not necessarily need to be kept constant. Of course, the effect of shortening the charging time is inferior to the case where the duty ratio (Q) is kept at the optimum value, but the charging time can be sufficiently reduced without keeping the duty ratio (Q) constant. Control can be performed.

In particular, in the battery using the charging device according to the present invention, as the electrode material, a battery using a material such as chalcogenite or a carbonaceous material in which the potential of the electrode changes monotonously with the progress of charging, the charge amount is kept constant without excess or shortage. it can. That is, in a non-aqueous battery in which a material capable of intercalating cations into the interstices of the molecular structure is used for either the positive electrode or the negative electrode, or for both the positive electrode and the negative electrode, the battery is charged by a chemical reaction on the surface of the electrode. Unlike many water-based batteries that discharge, the temperature change of the electrode potential is small and the potential of the electrode changes monotonically according to the amount of charge. The charging device according to the present invention, which can detect the charge amount of the battery and controls the charge amount at the end of charging by detecting the open-circuit voltage between the terminals of the battery during the off time that is very short compared to the on time,
The present invention is useful as a rapid charging device for a non-aqueous rechargeable battery device that performs charging current limiting type constant voltage charging.

Further, JP-55-13613, JP-Sho 62-90863, JP-rechargeable battery of nonaqueous disclosed in JP 63-299056 Laid, i.e., A _x M _y N _z O ₂ (A represents at least one kind of alkali metal, N represents at least one kind of non-transition metal, and x, y, and z are respectively 0.05 ≦ x ≦ 1.10, 0.85 ≦ y ≦
1.00, O ≦ z ≦ 0.10. ) As a rapid charging device for non-aqueous batteries that can be repeatedly charged and discharged using a positive electrode active material and a carbonaceous material as the negative electrode active material.
The present invention is particularly useful. Note in the composite oxide represented by the general formula A _x M _y N _z O ₂ is used as a positive Gokuomokatsu substance, M
Represents at least one transition metal, and N represents at least one non-transition metal. M is not particularly limited, but examples thereof include Co, Ni, Fe, Mn, V, and Mo. Similarly, N is not particularly limited, but Al, In,
Sn and the like.

By the way, when the present invention is specifically intended to be realized by an electronic circuit, a constant current power supply or a quasi-constant current power supply and a rechargeable battery device are connected via a switch means, and ON / OFF of the switch means is controlled by a control means. However, in this case, if the switch means is broken for any reason, the rechargeable battery device may continue to be charged at a constant current or a quasi-constant current. This leads to an overcharged state, which is not preferable for safety. Even if the switch means is destroyed for any reason, the constant current is maintained to minimize overcharge of the rechargeable battery device and to prevent the worst case in safety such as the rechargeable battery device from exploding. It is necessary to keep the maximum upper limit voltage of the power supply or the quasi-constant current power supply below a voltage that does not cause the worst case in safety such as the rechargeable battery device exploding. Therefore, at the end of charging when the voltage between terminals of the rechargeable battery device has risen considerably, in order to keep the charging current at a relatively large value and to shorten the charging time,
It is necessary to keep the resistance of the charging circuit low, especially the on-resistance of the switch means, and preferably to 300 mΩ or less. In particular, in order to perform switching in 1 μsec or more and to suppress the on-resistance value to 300 mΩ or less, it is preferable to use a field-effect transistor (FET). Further, an N-channel having a source-drain on-resistance of 300 mΩ or less. It turned out to be good to use MOS FETs.

[Action]

According to the present invention, for example, in charging of a non-aqueous rechargeable battery device in which charging current limiting type constant voltage charging is performed, after constant current charging or quasi-constant current charging, pulse charging is performed and charging is performed. In addition, it is possible to provide a rapid charging device capable of remarkably shortening the charging time as compared with the charging current limited type constant voltage charging.

〔Example〕

Hereinafter, an embodiment of a rapid charging device according to the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of the present invention. As shown in FIG. 1, a charging device 1 includes a constant current power supply or a quasi-constant current power supply 2,
The constant-current power supply or the quasi-constant-current power supply 2 is connected to a rechargeable battery device 6 via the switch unit 5. The voltage detection unit 4 is connected to the rechargeable battery device 6, and the voltage detection unit 4 is connected to the switch unit 5 via the control unit 3.
That is, the voltage between terminals of the rechargeable battery device 6 is detected by the voltage detection unit 4, and the control unit 3 controls the on / off of the switch means 5, that is, the charging current in accordance with the voltage between terminals of the rechargeable battery device 6. . When connecting the charging device 1 to the positive terminal and the negative terminal of the rechargeable battery device 6, it is preferable to separate the current terminal and the voltage detection terminal and connect them to four terminals.
The current terminal and the voltage detection terminal are connected inside the charging device 1,
Even if two terminals are connected, there is no problem in practical use. by the way,
The control unit 3 includes a determination circuit for determining the timing of shifting from constant-current charging or quasi-constant-current charging to pulse charging, a determination circuit for determining whether to suspend or end and restart pulse charging, and a pulse generation circuit.

In the control of the charging current, the switch means only needs to keep the ON state in the constant current charging or the quasi-constant current charging part, and in the pulse charging part, the pulse charging current is generated by turning on and off the switch means. The timing of shifting from the constant current charging or the quasi-constant current charging to the pulse charging is that the voltage between the terminals of the rechargeable battery device 6 during the constant current charging or the quasi-constant current charging has become equal to or higher than the first voltage (V _off ). , And shifts from constant current charging or quasi-constant current charging to pulse charging. When controlling on-time during the pulse charging (t _on) and the duty ratio _{{Q = t on / (t} on + t off)} constant, the signal generated by the pulse generating circuit of the control unit 3, the switch means The pulse charging is performed by converting the signal into an on-off signal of 5 and outputting the signal to the input of the switch means 5 to turn on and off the switch means 5. Therefore, the timing of interrupting or terminating the pulse charging and resuming the timing is determined based on the voltage between the terminals of the rechargeable battery device 6 when the charging current is off, and the voltage between the terminals of the rechargeable battery device 6 when the charging current is off is determined. A second voltage (V ^PC ) higher than the first voltage (V _off )
_off ) When the above is reached, the output of the control unit 3 outputs an off signal to the switch means 5, and the pulse charging is interrupted or terminated. Further, a function of detecting that the voltage between terminals of the rechargeable battery device 6 has dropped to a third voltage (V ^PC _on ) lower than the second voltage (V ^PC _off ) or less and restarting pulse charging again is provided. May be added. In this case, the voltage between the terminals of the rechargeable battery device 6 when the charging current is turned off again becomes the second voltage (V ^PC _off ).
Then, the pulse charging is interrupted again. further,
If the interruption and resumption of the pulse charging are repeated n times, a function of stopping the pulse charging may be added. When suspending and resuming pulse charging, (V
^PC _off -V ^PC _on ) is desirably set to about 0.1 V or less.

Further, when a charging method in which the duty ratio (Q) changes following the constant-current charging or the quasi-constant-current charging is employed, the pulse generation circuit can be omitted and pulse charging can be easily realized. That is, when the voltage between the terminals of the rechargeable battery device 6 at the start of charging is lower than the first voltage (V _off ),
The constant current charging or the quasi-constant current charging is performed. If the voltage between the terminals of the rechargeable battery device 6 becomes equal to or higher than the first voltage (V _off ) during the constant current charging or the quasi-constant current charging, the predetermined on-time (t) _on ) The charging current is cut off after the current flows for
When the voltage becomes lower than a fourth voltage (V _on ) lower than the voltage (V _off ), the charging current flows, and when the voltage between terminals of the rechargeable battery device becomes higher than the first voltage (V _off ), the on state turns on. By repeatedly continuing to interrupt the charging current after flowing for a time (t _on ) or more, pulse charging in which the off time (t _off ) changes according to the charged amount is performed after constant current charging or semi-constant current charging. be able to.

Next, the case where the pulse charging method in which the duty ratio (Q) changes, following the constant current charging or the quasi-constant current charging, will be specifically described with reference to the drawings. Second
The figure shows an example of a circuit that can realize pulse charging in which the on-time (t _on ) is constant and the off-time (t _off ) changes according to the amount of charge. The charging device 1 shown in FIG. 2 forms a Schmitt circuit with a comparator 9 that compares a reference voltage set by a reference voltage circuit 8 with a voltage between terminals of the rechargeable battery device 6, and forms a first voltage (off). A voltage (V _off ) and a fourth voltage (on voltage) (V _on ) are set. That is, the hysteresis of the comparator 9 can be set by the value of the resistor 10,
The width of the hysteresis of the comparator 9 (V _off -V _on )
It is desirable to set to about 0.1V or less. That is, when the charging is not sufficiently progressing and the charging current is cut off, the charging overvoltage (η = γ _in · I ^PC , γ _in ; internal resistance of the rechargeable battery device 6, I ^PC ; pulse charging current) When the voltage between terminals of the rechargeable battery device 6 immediately drops below the on-voltage (V _on ), the off-time (t _off ) takes almost the same value as the value at the start of pulse charging, and the duty ratio ( Q) The charging close to the pulse charging with the fixed Q) can be realized, and the average charging current is almost constant. When the charging current is cut off, the voltage between terminals of the rechargeable battery device 6 decreases due to a charging overvoltage (η = γ _in · I ^PC , γ _in ; internal resistance of the rechargeable battery device 6, I ^PC ; pulse charging current). However, if charging immediately proceeds to a state where the voltage does not fall below the on-voltage (V _on ), the off-time (t _off ) increases sharply compared to the value at the start of pulse charging, and as a result, the average charging current increases. It decreases rapidly and charging ends.

Next, the on-time (t _on ) is measured by the capacitor 11 and the resistor 1
2. The setting is made using the comparator 13, the resistor 14, and the like. That is, when the inter-terminal voltage of the rechargeable battery device 6 is lower than the off voltage (V _off ), the comparator 9 is on and charges the capacitor 11. At the same time, discharge occurs through the resistor 12, but the discharge current through the resistor 12 of the capacitor 11 is set sufficiently smaller than the charge current of the capacitor 11, and the capacitance of the capacitor 11 and the comparator are set according to the reference voltage. 13 hysteresis magnitude resistor
Set at 14 and adjust to desired on-time (t _on ).

Accordingly, a rechargeable battery device 6 is disclosed in Japanese Patent Laid-Open No. 62-90863.
A case in which a charging device for charging an assembled battery in which two secondary batteries described in No. 2 are combined in series and the charging is performed will be specifically described. The standard operating voltage range of the secondary battery is 2.75 V to 4.2 V per cell, and 5.5 V to 8.4 V for an assembled battery in which two batteries are connected in series. In this embodiment, a rapid charger of a battery device having a capacity of 2.0 Ah, which is prototyped as a power supply for a video movie, will be described as an example.

The standard charging condition of the rechargeable battery device is a constant voltage charging of 8.4 V with a charging current battery limited to 2.0 A (1 C) or less,
The charging time is 3 hours.

Therefore, the power supply section has a maximum upper limit voltage of 9.2V, 2.0A
Using the constant current source, 8.445V ON voltage (V _on), off-voltage (V _off) and 8.400V, on-time (t _on) of about 100 msec,
The charging device was prototyped by setting the off time (t _off ) immediately after the transition to pulse charging to about 4 msec, and the rechargeable battery device was charged. Charging was completed in about 1.5 hours, significantly shortening the charging time. Was achieved.

An N-channel MOS FET with a source-drain ON resistance of about 100 mΩ is used as the switch means 15, and a Schottky diode with a voltage drop of about 0.5 V when a current of 2 A is applied is used as the backflow prevention diode 16. did.

Of course, when the present invention is applied to a rechargeable battery device that can be detachably mounted, whether the rechargeable battery device is mounted on the charging device, whether the rechargeable battery device is short-circuited, or the like is determined. And additional functions such as a charge control function based on the determination result, a timer, and a function of displaying a charge state, an adapter function, and the like may be added.

〔The invention's effect〕

As described in detail above, according to the present invention, it is possible to provide a charging device that can significantly reduce the charging time when charging a non-aqueous rechargeable battery device that requires current-limited constant-voltage charging.

[Brief description of the drawings]

 FIG. 1 is a block diagram of the present invention, and FIG. 2 is a diagram showing an example of a circuit according to an embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H02J 7/00-7/12 H02J 7/34-7/36 H01M 10/44

Claims (1)

(57) [Claims] 1. A non-aqueous rechargeable battery device using a material capable of intercalating cations into gaps of a molecular structure in one of a positive electrode and a negative electrode or both of the positive electrode and the negative electrode. Or a quasi-constant current power supply, switch means inserted in series in a charging / discharging circuit between the power supply and the rechargeable battery device, voltage detecting means for detecting a voltage between terminals of the rechargeable battery device, When the inter-terminal voltage at the start of charging is lower than the first voltage based on the detection result of the means, the switch means is continuously turned on, and after the inter-terminal voltage reaches the first voltage, The charging means is pulse-charged by repeatedly turning on and off the switch means to interrupt the charging current from the power supply, and the inter-terminal voltage when the pulse charging is turned off is Charging apparatus being characterized in that comprises a charging control unit that ends the pulse charging when exceeding the high second voltage from the first voltage.