JPH10322926A - Charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate a secondary battery from a dry battery with a simple structure on the charging device side, even if they are of the same shape. SOLUTION: This device is provided with a means which conducts charging by the prescribed time at the first current value corresponding to initial charging, discriminates that it is in an abnormal condition if the voltage across the battery of larger than the first voltage is detected (step 109) to have a charging current supply stopped (step 121) and controls charging current, so as to be set to the second current value for quick charging or the like, assuming that a normal secondary battery has been fitted if the voltage across the battery smaller than the first voltage is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device suitable for application to, for example, a charging device for charging a secondary battery having substantially the same shape as a dry battery.

[0002]

2. Description of the Related Art Conventionally, secondary batteries (rechargeable batteries) such as nickel cadmium batteries and nickel hydrogen batteries have been
2. Description of the Related Art Some electronic devices which can be used as a power source by using a dry battery as a power source are configured so as to have the same shape as a dry battery (eg, an alkaline dry battery or a manganese dry battery) such as a mold.

As described above, since a secondary battery can be used in place of a dry battery, when an electronic device using a battery as a power source is used, it is not necessary to purchase a new battery as long as charging is performed, and the electronic device is used. In this case, the running cost can be significantly reduced.

[0004]

A secondary battery used in place of such a dry battery has a terminal voltage close to the battery voltage of a dry battery having a terminal voltage of about 1.2 V. Has the same shape as a dry battery such as an AA battery. However, if the shape of the battery is exactly the same,
If you accidentally insert batteries into the device that charges the next battery,
A charging operation is performed on the attached dry battery, which may result in a dangerous state.

[0005] For this reason, two batteries that can be used in place of dry cells are used.
In the case of a secondary battery, it is often the same shape as a dry battery such as an AA type battery, but often has a shape that can be distinguished from the dry battery on the charging device side. For example, in the case of a secondary battery for an electronic device in which two AA batteries are mounted and used, the two AA batteries are used as a rechargeable battery having a shape connected to the two AA batteries. Some idea is given to the shape of the connection part of the secondary battery. And on the charging device side,
The connection portion of the secondary battery of the book is configured to be detectable by a mechanical switch or the like. By doing so, when the charging device detects the installation of the battery, when the switch detects the connection portion of the secondary battery, it is determined that the secondary battery is installed, and the charging operation is performed. When the connection is not detected, it is determined that the dry battery is incorrectly attached, and the charging operation is not performed.

[0006] With this configuration, only the secondary battery can be charged by the charging device. However, if this is done, a secondary battery that can be used in place of a general-purpose dry battery can be used. However, it can be used only for an electronic device having a battery mounting portion (battery case) corresponding to a shape of a connection portion or the like that can be distinguished from a dry battery, and the use of a secondary battery is limited. In addition, the charging device also requires a mechanical switch or the like for detecting the connection and the like, and thus has a problem in that the configuration of the charging device is complicated.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to make it possible to easily distinguish a secondary battery from a battery when the battery has the same shape as the battery.

[0008]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a method of charging a battery at a first current value corresponding to an initial charge up to a predetermined time to obtain a terminal of a battery having a first voltage or more. When the inter-voltage is detected, it is determined that the battery is abnormal, and the supply of the charging current is stopped. When the inter-terminal voltage of the battery is equal to or less than the first voltage, it is determined that a regular secondary battery is mounted. Control is performed to set the current to a second current value such as for rapid charging.

According to the present invention, when the inter-terminal voltage becomes equal to or higher than the first voltage during the initial charging at the first current value, it is determined that the inter-terminal voltage of the battery is abnormally high. When there is a possibility that there is a possibility that the charging is stopped, and the voltage is equal to or lower than the first voltage even after a predetermined time has elapsed, it is determined that the battery has the battery characteristics of the secondary battery and the battery is suitable for the secondary battery. Charging is performed.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of the charging device of this embodiment. In this embodiment, the charging device has the same shape as an AA dry battery.
Secondary battery charged by constant current charging (battery voltage is 1.
A charging device capable of charging two (2V nickel-metal hydride batteries) simultaneously (or individually). In order to charge the two secondary batteries, a charging circuit for the first channel and a second It has two charging circuits of a two-channel charging circuit. The charging device of this example is configured to connect and use a commercial AC power supply (AC100V or the like) called an AC adapter with a converter (not shown) that rectifies and transforms the power. The charging operation is performed using the DC voltage power supply obtained as described above as a power supply. Note that A
Instead of the C adapter, a DC voltage power supply from a converter for transforming a DC power supply from an automobile battery or the like may be supplied to the power supply input terminal 11.

The power supply voltage obtained at the power supply input terminal 11 is:
The input voltage is detected by the input voltage detection circuit 12 and the detection data is supplied to the controller 13. The controller 13
This is a controller composed of a microcomputer for controlling the charging operation of the charging device.
The charging operation of each channel is controlled by supplying the PWM control signal of each channel (the PWM control signal S ₁₁ of the first channel and the PWM control signal S ₂₁ of the second channel) to the CPU.

In this case, the controller 13 detects the voltage between the terminals of the battery B ₁ connected to the charging circuit of the first channel and the voltage between the terminals of the battery B ₂ connected to the charging circuit of the second channel. A terminal 13b is provided, and the voltage between the terminals of the batteries connected to the respective charging circuits can be detected based on the voltages obtained at the terminals 13a and 13b.
Then, the control state of the charging operation is set based on the detected inter-terminal voltage. Although the details of the charge control state by the controller 13 will be described later, in the present example, charging is performed first with a relatively small current in the initial charging mode, and when a certain condition is satisfied in the initial charging mode, rapid charging is performed. Control is performed to charge with a relatively large current in each mode. When the detected inter-terminal voltage exceeds the value set in each mode during charging in each mode, a normal secondary It is determined that the battery is not a battery (that is, there is a possibility that the battery is a dry battery), and a process of stopping charging is performed.

The PWM circuit 14 includes a charging current detection circuit 2
On the basis of the charging current detected at 3, 33, a pulse width modulated wave (PWM wave) of a predetermined frequency is output for each channel as DC / DC converter control signals S ₁₂ and S ₂₂ to keep the charging current constant. It is a circuit to make. DC / DC converter control signal S of the first channel
₁₂ is supplied to the first channel of the DC / DC converter 21, in the DC / DC converter 21, an input power source voltage Vin obtained at the power supply input terminal 11, a voltage V ₁₀ instructed by the control signal. DC / DC converter control signal S ₂₂ of the second channel is supplied to the DC / DC converter 31 of the second channel, in the DC / DC converter 31, an input power source voltage Vin obtained at the power supply input terminal 11, the control the voltage V _20, which is indicated by the signal. In the following description, the power supply current obtained at the power supply input terminal 11 is defined as I ₀ , the current supplied to the DC / DC converter 21 of the first channel is defined as I ₁ , and the current supplied to the DC / DC converter 31 of the second channel is defined as I _0. The supplied current is I ₂ , the output current of the first channel DC / DC converter 21 is I ₁₀ , the second channel DC / DC converter
The output current of the DC converter 21 and I _20.

First channel DC / DC converter 2
1 are output from the battery connection terminals 22a, 2 of the first channel.
Is supplied to 2b, the connection terminals 22a, by connecting the positive and negative electrodes of the battery (secondary battery) B ₁ to 22b, battery B ₁ is being charged. Here, DC / DC converter 2
1 and a connection terminal 22b, a charging current detection resistor R1 is inserted, and one end of the resistor R1 is connected to the charging current detection circuit 23. This charging current detection circuit 2
In 3, the resistor charging current detected by R1, is detected in a predetermined state under control of the controller 13, the detection signal S ₁₃ (signal indicating the charge current voltage) amplifier 2
4 to the PWM circuit 14. PWM circuit 14
So as with its charging current detection signal S ₁₃ proper charging current is detected, and controls the first channel of the DC / DC converter 21, a constant current charge at a current value set for each mode I do. Switching of the charging current is performed by supplying a predetermined signal from the controller 13 to the detection circuit 23.

Second channel DC / DC converter 3
1 is output from the battery connection terminals 32a, 3 of the second channel.
Is supplied to 2b, the connection terminals 32a, 32b to be to connect the positive and negative electrodes of the battery (secondary battery) B _2, the battery B ₂ is charged. Here, the DC / DC converter 3
A charging current detection resistor R2 is inserted between the terminal 1 and the connection terminal 32b, and one end of the resistor R2 is connected to the charging current detection circuit 33. This charging current detection circuit 3
In 3, the charging current detected by the resistor R2, is detected in a predetermined state under control of the controller 13, the detection signal S ₂₃ (signal indicating the charge current voltage) amplifier 3
4 to the PWM circuit 14. PWM circuit 14
So as with its charging current detection signal S ₂₃ proper charging current is detected, and controls the DC / DC converter 31 of the second channel, constant-current charging at a current value set for each mode I do. Switching of the charging current is performed by supplying a predetermined signal from the controller 13 to the detection circuit 33.

As a configuration in which the controller 13 detects the battery voltage, the battery connection terminal 22a of the first channel is
The resistor R3 and the capacitor C1 are grounded via a series circuit, and the connection point between the resistor R3 and the capacitor C1 is connected to the terminal-to-terminal voltage detection terminal 13a of the controller 13. Also, the battery connection terminal 32 of the second channel
a is grounded via a series circuit of a resistor R4 and a capacitor C2, and the midpoint of connection between the resistor R4 and the capacitor C2 is
b.

The controller 13 includes resistors R5, R
6, R7, R8, four light emitting diodes D1, D
2, D3, and D4 are connected, and the light emission of each of the light emitting diodes D1, D2, D3, and D4 is controlled according to the charge control state at that time, and the charge state is displayed. Specifically, the light emitting diodes D1 and D3 are red light emitting diodes, the light emitting diodes D2 and D4 are green light emitting diodes, and the light emitting diodes do not emit light in a standby mode where charging is not performed. Control is performed such that red is continuously emitted in the quick charge mode, green is continuously emitted in the trickle charge mode and the charge termination mode, and red is flashed in the abnormal mode.

Although not shown, the controller 13 of the present embodiment is also configured so as to be able to determine the temperature of the battery, and the controller 13 can perform an appropriate charging stop process when the temperature is abnormal.

Next, an operation when charging is performed by the charging device of the present embodiment will be described with reference to a flowchart of FIG. The flowchart of FIG. 2, an illustration first channel of the connection terminals 22a, the processing in the case of charging the battery B ₁ that is connected to 22b, the same as the charging process, even if the second channel, the charge Only the circuit is different.
In this flowchart, the voltage Va is a battery B ₁ detected by an inter-terminal voltage detection terminal 13a of the controller 13.
Battery voltage.

In the following description and flowcharts, it is assumed that there is a battery. First, when there is a power input of a specified voltage from an AC adapter or the like to the power input terminal 11 (step 101), each circuit such as the controller 13 is operated by the power source, and the controller 13 operates the battery detected by the terminal 13a. The terminal-to-terminal voltage Va is a predetermined low voltage V
₁ and determines whether a during an overvoltage V ₂ (Step 1
02). In the case of this example, it is set 1.0V low voltage V _1, an overvoltage V ₂ to 2.0 V. Here, if it is not within this range, the process waits at this step and does not proceed to the initial charging operation. In the case of low voltages V ₁ or less, moved here to a low voltage charging mode which is not described, the low voltages V ₁
The process of returning to the above battery voltage is performed. Step 10
2, the inter-terminal voltage Va is a low voltage of the battery V ₁ and overvoltage V ₂
When it is determined that the voltage range between the a PWM control signal S ₁₁ of the first channel is turned on (step 103), the control signal S from the PWM circuit 14 to the first channel of the DC / DC converter 21
The supply of ₁₂ is started (step 104).

[0022] In the supply of this control signal, the charging current detection signal S ₁₃ supplied are detected by the charging current detecting circuit 23, determines approximately equal or not the voltage V ₃ which is set (step 105), equal to If not, DC / DC
Correspondingly varying the control signal S ₁₂ to the converter 21 (step 106), the flow returns to the determination at step 105. If the signal S ₁₃ is determined to substantially equal to the voltage V ₃ at step 105, to fix the control signal S ₁₂ to the value at that time (step 107).

Next, determine the charging time from to initiate the initial charge in step 104, it is determined whether or not the charging time has reached a predetermined time t ₁ which is set in advance (Step 1
08), to wait until that time t _1. In this example,
As the predetermined time t ₁ is set to 5 minutes. When the predetermined time t ₁ has elapsed, the controller 13 switches to the terminal 13a.
In terminal voltage Va of the battery is detected, it determines whether the value of less than the voltage V ₄ for batteries detected in the initial charge mode (step 109). In the case of this example, the voltage V ₄ for batteries detection in the initial charge mode, there as 1.70 V. The voltage V ₄ for detecting dry batteries in this initial charging mode
Is set to, for example, a normal 2 which is charged by the charging device of this example.
The charging current (about 400 mA) in the initial charging mode is continuously supplied to the secondary battery (nickel-metal hydride battery) for a predetermined time t ₁ , and is slightly higher than the highest possible voltage value between the terminals of the secondary battery. Set the voltage value.

[0024] In step 109, if the inter-terminal voltage Va detected by the terminal 13a is at a voltage V ₄ or the controller 13 determines the terminal 22a, the battery B ₁ that is connected to 22b is a battery Then, the process proceeds to the charging stop process (step 121). The charge stop processing at step 121, for example, the OFF state of the PWM control signal S ₁₁ of the first channel, the first channel D
The supply of the charging current from the C / DC converter 21 is stopped, and the abnormal mode is displayed by the light emitting diode connected to the controller 13.

[0025] Control 1 and terminal voltage Va detected by the terminal 13a at step 109 is less than the voltage V ₄
When the determination is made in step 3, control is performed to change the charging current to the charging current in the rapid charging mode (here, about 650 mA) (step 110). After switching this charging current,
If the charging current detection signal S ₁₃ supplied are detected by the charging current detecting circuit 23, it determines approximately equal or not the voltage V ₃ which is set (step 111), not equal, D
Correspondingly varying the control signal S ₁₂ to the C / DC converter 21 (step 112), the flow returns to the determination at step 111. If the signal S ₁₃ is determined to substantially equal to the voltage V ₃ 'at step 111, to fix the control signal S ₁₂ to the value at that time (step 113).

Next, the controller 13 is the inter-terminal voltage Va detected by the terminal 13a, determines whether becomes equal to the voltage V ₅ for battery detection in fast charge mode (step 114). In the case of this example, the voltage V ₅ for detecting batteries in the rapid charge mode and a 1.75V.
This rapid voltage V ₅ for detecting batteries in the charging mode is set, for example, a normal secondary battery to be charged by the charging device of the present embodiment the charging current in the quick charge mode (NiMH batteries) (about 650 mA) The voltage is supplied continuously and set to a voltage value slightly higher than the highest possible voltage value between the terminals of the secondary battery.

[0027] In step 114, if the terminal voltage Va of the battery detected by the terminal 13a controller 13 determines that becomes equal to the voltage V _5, the terminal 22a, 22
battery B ₁ that is connected to the b is determined to be a dry battery, and proceeds to the charge stop processing (step 121).

[0028] In step 114, if the terminal voltage Va of the battery detected by the terminal 13a is determined not to voltage V ₅ is the battery voltage Va of that time, preset low voltages V ₁ determines whether or not during an overvoltage V ₂ (step 115). The lowest voltage V ₁ and overvoltage V here
₂ is the same as the value described in step 102. In this step 115, when the terminal voltage Va is judged not in the range between the low voltage V ₁ and the overvoltage V ₂ proceeds to the charging stop process (step 121).

[0029] When the terminal voltage Va is determined to be in the range between the low voltage V ₁ and the overvoltage V ₂ in step 115, the temperature anomaly from the output of the temperature detecting element which the charging device is provided (not shown) Is determined (step 116), and if it is determined that the temperature is abnormal, the process proceeds to a charging stop process (step 121).

When it is determined that the temperature is not abnormal, a so-called -ΔV detection, which is a detection of a state where the voltage Va between the terminals of the battery detected at the terminal 13a decreases, is performed. Is determined (step 117). Here, if the state in which the inter-terminal voltage Va decreases is not detected, the process returns to the determination in step 115, and until the state in which the inter-terminal voltage Va decreases is detected.
Steps 115, 116 and 117 are repeated.

If it is detected in step 117 that the inter-terminal voltage Va has dropped, the operation proceeds to the trickle charging mode. In the trickle charging mode, the charging current for trickle charging (about 60 in the present example) is controlled by the controller 13.
mA) (step 118). When the trickle charging is set, it is determined whether or not the elapsed time from the start of charging in steps 103 and 104 is a predetermined time t _x (6 hours in this example) (step S 104). 119). From the start of charging up to this time t _x has elapsed, we do continue to trickle charging at step 118,
When it is determined that the time t _x has elapsed, performs processing to stop charging (step 120).

FIG. 3 is a diagram showing an example of the case where the secondary battery is charged by such processing. In this example, the secondary battery B ₁ is first connected to the connection terminals 22a and 22b of the charging circuit of the first channel. After a certain period of time has passed since the battery was mounted and charging was started, the connection terminal 3 of the charging circuit of the second channel was connected.
2a, by mounting the secondary battery B ₂ to 32b, illustrates a process when to start charging. As shown in A of FIG. 3, the first channel of the connection terminals 22a, when the mounted secondary battery B ₁ to 22b, the initial charge of 5 minutes is performed.
In this initial charge mode, approximately as the charging current I ₁₀ 400
mA is set to increase the battery voltage V ₁₀ is gradually After five minutes from the initial charging, proceeds to fast charge mode. The quick charge mode, is set to approximately 650mA as the charging current I _10, to increase the battery voltage V ₁₀ is gradually battery voltage V ₁₀
Is decreased, the detection of -.DELTA.V is performed, and the mode shifts to the trickle charging mode.

[0033] for the second channel, as shown in B of FIG. 3, the connection terminals 32a, the secondary battery B ₂ is attached to 32b, after the initial charge of 5 minutes was performed, quick charge line Then, the detection is switched to trickle charging upon detection of -ΔV, and the charging current I ₂₀ and the battery voltage V ₂₀ change correspondingly. The input voltage from the input terminal 11 which is detected by the controller 13, the charging current I ₀ that corresponds to changes to changes in the charge state of each channel as shown and C, were combined both channels of FIG. 3 FIG. 3 as indicated by D.

As described above, in the case of the charging device of the present embodiment, the charging process is performed independently for each channel, and the two secondary batteries are fully charged while being appropriately and separately controlled. Can be in a state.

If the battery mounted on any channel is not a secondary battery but a dry battery (alkaline battery, manganese battery, etc.), charging stops for that channel and an error message is displayed. Done. That is, FIG. 4 shows an example in which a dry battery is mounted. For example, when a dry battery having certain characteristics is erroneously mounted on the terminals 22a and 22b (or the terminals 32a and 32b), the terminal 13a
(Or the terminal 13b) is the voltage V in FIG.
_The state changes as indicated by _X , and exceeds a preset voltage V ₄ (1.70 V in this example) during initial charging. Therefore, comparison with the voltage V ₄ at the time when the initial charging is completed (the processing of step 109 in the flowchart of FIG. 2)
Therefore, it is determined that the battery of this channel is not a normal secondary battery, a charging stop process is performed, and a dry battery or the like is not erroneously charged.

[0036] In addition, even if the battery voltage during this initial charge is allowed to charge the batteries of the property does not exceed the voltage V ₄ event,
During charging in the rapid charging mode, as a change state indicated by the voltage V _y of FIG. 4, the battery voltage will exceed the voltage V _5, compared with the voltage V ₅ at the fast charge (in FIG. 2 In step 114 of the flowchart), it is determined that the battery of this channel is not a normal secondary battery, and a charging stop process is performed.

Therefore, according to the charging apparatus of this embodiment, when a dry battery or a secondary battery having abnormal characteristics is mounted, the charging of the battery is stopped, and it is possible to prevent the dry battery or the like from being erroneously charged. In this case, since the detection of the dry battery or the like is performed from the voltage detection, it is possible to correctly detect the secondary battery and the dry battery even if they have exactly the same shape, and it is necessary to take some measures to distinguish the secondary battery from the dry battery. High security is secured without preparing a dedicated secondary battery, and compared to the case where the secondary battery is detected from the shape,
A switch for detecting the shape and the like is not required, and the configuration of the charging device can be simplified.

The values such as the voltage value, the current value, and the charging time shown in the above-described embodiment are merely examples, and appropriate values may be set according to the type, characteristics, and capacity of the battery to be charged. May change.

In the above-described embodiment, a single charging device operated by a power supply from an AC adapter or the like is used. However, a charging circuit in a case where a charging circuit is built in an electronic device driven by a secondary battery is described. It can be applied to control.

In the above-described embodiment, the charging circuit controls the conversion by the DC / DC converter based on the frequency of the PWM wave to perform the constant current charging. However, the present invention is applied to a charging circuit having another configuration. Of course, you can do that.

In the above-described embodiment, the charging device can charge two rechargeable batteries individually. However, the charging device can charge only one rechargeable battery, or can charge more charging devices. Of course, the present invention can be applied to a charging device. Also, the secondary battery to be charged can be applied to various secondary batteries (such as nickel cadmium batteries) other than the nickel-metal hydride battery described in the above embodiment.

[0042]

According to the first aspect of the present invention, the first
When the inter-terminal voltage becomes equal to or higher than the first voltage during the initial charging with the current value of, the inter-terminal voltage of the battery is determined to be abnormally high, and the charging is stopped because there is a possibility that the battery is a dry battery. When the processing is performed and the voltage is equal to or lower than the first voltage even after the lapse of the predetermined time, it is determined that the battery has the battery characteristics of the secondary battery, and charging suitable for the secondary battery is performed. Therefore, the dry battery and the secondary battery can be distinguished from each other based on the difference in the characteristics of the battery voltage, and only when the mounted battery is the secondary battery, the secondary battery is correctly charged. It has an effect that can be prevented. In addition, when charging a secondary battery having the same shape as the dry battery, the dry battery is connected to the dry battery by a mechanical switch or the like.
It is not necessary to distinguish the secondary battery from the secondary battery, and the configuration in the case of a charging device for a secondary battery having a shape corresponding to a dry battery can be simplified.

According to the second aspect of the invention, when the second current value is set, the voltage between the terminals detected by the voltage detecting means becomes the second voltage higher than the first voltage. When the supply of charging current is stopped,
Detection when a dry battery is attached can be performed more reliably, and erroneous charging of the dry battery can be more effectively prevented.

According to the third aspect of the present invention, the maximum potential between the terminals when the charging current of the first or second current value is supplied to the normal secondary battery as the first and second voltages. By setting the voltage to a value higher than the voltage, there is an effect that the dry cell detection in each case can be accurately performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a charging device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a charging process according to the embodiment of the present invention.

FIG. 3 is a timing chart during charging according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an example of a battery voltage change when a primary battery is mounted according to the embodiment of the present invention.

[Explanation of symbols]

11: power supply input terminal, 13: controller, 13a: voltage detection terminal between terminals of the first channel, 13b: voltage detection terminal between terminals of the second channel, 14: PWM circuit, 21
... DC / DC converter of first channel, 22a, 2
2b: Battery connection terminal of the first channel, 23: Charge current detection circuit of the first channel, 31: D of the second channel
C / DC converters, 32a, 32b: battery connection terminals of the second channel, 33: charging current detection circuit of the second channel, B ₁ : batteries connected to the first channel, B ₂ ...
Cells connected to the second channel, S ₁₁ ... first channel PWM control signal, S ₁₂ ... DC / DC converter control signal of the first channel, S ₁₃ ... charging current detection signal of the first channel, S ₂₁ ... first 2 channel PWM control signal, S ₂₂ ... 2 channel DC
/ DC converter control signal, S ₂₃ ... Second channel charging current detection signal

Claims (3)

[Claims] 1. A charging device for charging a connected secondary battery, wherein a charging current for the mounted battery is determined by a first current value and the first current value.
Charging current setting means for setting a second current value higher than the current value of the first battery, and voltage detecting means for detecting a voltage between terminals of the mounted battery, wherein the first current value is the charging current setting means. When charging is performed for a predetermined time and the voltage detecting means detects a terminal-to-terminal voltage equal to or higher than the first voltage, the supply of the charging current is stopped, and the voltage between the terminals equal to or lower than the first voltage is set. A charging control means for setting the charging current having the second current value by the charging current setting means when the voltage is a voltage; 2. The charging device according to claim 1, wherein the voltage between the terminals detected by the voltage detecting means is equal to the first voltage when the second current value is set by the charging current setting means. A charging device wherein the charging control means stops supplying a charging current when the second voltage becomes higher than the voltage. 3. The charging device according to claim 2, wherein the first and second voltages have a maximum possible value when a charging current having the first or second current value is supplied to a normal secondary battery. Charger set to a value higher than the terminal voltage.