JPH08191544A - Charger - Google Patents

Abstract

PURPOSE: To surely conduct the keeping of the release and non-operation state, in a battery to be charged having a protective circuit. CONSTITUTION: A charger 1 makes a battery to be charged 2 having a protective circuit 20 inside chargeable. The charger 1 consists of a microcomputer circuit section 20 which controls the charging operation and a charging operation circuit section 10' which is operated by the microcomputer circuit section 20. The microcomputer circuit section 10 is constituted of a multistage switching circuit 101 which switches charging current in stages and a switching controlling means 102 which switches the multistage switching circuit 101 in order to increase the charging current in stages according to the preset charging procedures when charging is started for the purpose of resetting the protective circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for charging a battery to be charged, which has a protection circuit which is activated when a rapid change in charging current is detected to shut off the current supply to the battery to be charged, The present invention relates to a charging device adapted to release or inactivate a protection circuit.

[0002]

2. Description of the Related Art Conventionally, various charging devices have been provided which supply a constant current to a chargeable / dischargeable secondary battery and, when a predetermined condition is reached, regard it as a full charge and complete the charging. In addition, as a secondary battery, nickel-based materials such as Ni-Cd and Ni-MH are known. Further, like a lithium battery, a protection circuit is built in to prevent overcharging during charging. Things have come to the market.

[0003]

The conventional charging device merely serves to secure a constant current and does not positively control the output, and therefore, charging various secondary batteries. It's not easy to do. In particular, it is not possible to charge a secondary battery including a protection circuit such as a lithium battery in addition to a nickel-based battery.

The present invention has been made in view of the above,
For a battery to be charged that has a protection circuit by giving a gradient to the charging current at the start of charging and raising it to a predetermined level,
It is an object of the present invention to provide a charging device that surely releases the operating state of the protection circuit and maintains the non-operating state.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a charging device for charging a battery to be charged, which has a protection circuit which is activated when a rapid change in charging current is detected to shut off the current supply to the battery to be charged. The charging device further comprises switching means for changing the level of the charging current, and switching control means for operating the switching means so as to increase the charging current at a predetermined gradient for a predetermined time at the start of charging. 1).

Further, the switching means allows the charging current to be switched stepwise, and the switching control means stepwise increases the charging current from 0 level (claim 2). .

Further, according to the present invention, there is provided a determination means for determining the release state of the protection circuit at the start of charging, and the switch control means is operated when it is determined that the protection circuit is not released. (Claim 3).

Further, the determining means may determine the released state based on the voltage level of the battery to be charged (claim 4).

Further, the switching control means increases the charging current for the predetermined time and then successively increases it to the current value in the normal charging (claim 5).

Further, the present invention is provided with a confirmation means for confirming the release of the protection circuit when the charging current is increased for the predetermined time, and when the release is confirmed, the normal charging is started. (Claim 6).

[0011]

According to the first aspect of the invention, at the start of charging, the charging current is increased for a predetermined time while the level is sequentially changed at a preset gradient. In this way, when the charging current is not steep at the start of charging and is supplied for a predetermined time with a certain gradient, the protection circuit for the battery to be charged does not operate (maintains the non-operation state) or is in the operation state. Things (not released) are released. Therefore, after this, normal charging becomes possible. The gradient may be linear or curvilinear.

According to the second aspect of the present invention, at the start of charging, the charging current is switched stepwise and gradually increases, so that the protection circuit does not operate or is released.

According to the third aspect of the invention, the determination means determines the release state of the protection circuit at the start of charging, and when it is determined that the release state is not released, the switching control means is operated,
The cancellation is performed.

According to the fourth aspect of the present invention, since the battery to be charged is connected to the charging device, the determination of the release state of the protection circuit is performed by simply detecting the battery voltage level. If it is not released, the battery voltage is not output, so it is easy to see that the protection circuit is operating.

According to the fifth aspect of the invention, the charging current is increased for a predetermined time at the start of charging, and then the normal charging is subsequently performed, so that the rapid charging is performed.

According to the sixth aspect of the invention, since the release of the protection circuit is confirmed before the shift to the normal charge, the protection circuit operates even if the shift to the normal charge is made. Absent.

[0017]

FIG. 1 is a block diagram showing the relationship between a charger equipped with a charging device according to the present invention and a battery to be charged by this charger. In the figure, 1 is a charger and 2 is a battery to be charged. If the battery 2 to be charged is, for example, a lithium battery, a ROM 2A as a memory is built therein, and parameters necessary for charging are stored in the ROM 2A in a predetermined format. In addition, the charging target battery 2 is provided with a protection circuit 20 that prohibits the inflow of the charging current when a relatively large current (for example, 50 mA or more) for normal charging is supplied from the start of charging. The charger 1 and the battery 2 to be charged are connected by a required number of signal lines by mounting them.

In the charger 1, a microcomputer circuit 10 and a charging operation circuit section 10 'controlled and driven by the microcomputer circuit 10 are provided. In the microcomputer circuit 10, charging control is performed according to a predetermined charging procedure, and the battery to be charged 2
Is equipped with a program so that it can be charged. Reference numeral 101 denotes a multi-stage switching circuit capable of finely changing and setting the charging current in multiple stages. Switching control of the charging current for releasing the protection circuit 20 at the start of charging or current control in normal charging is performed by the switching control means 102. Digitally reliable and easy.

FIG. 2 is a block diagram showing an example of a connection mode of a charger to which the charging device according to the present invention is applied. The charger 1 charges a lithium battery and other kinds of charged batteries. Reference numeral 3 is a load device that uses the battery to be charged 2 as a power source, and is, for example, a mobile phone. When the battery 2 to be charged is a lithium battery, the ROM 2A in the lithium battery also stores data necessary for the telephone to grasp the characteristics of the lithium battery. And
Power supply and transmission of the above data are performed via the line l1. The charger 1 can also be connected to the line l1 via a line l2.
The charging current of the charger 1 can be electrically connected to a line for power supply in the line l1, and a line for reading the above parameters can be electrically connected to a line for data transmission in the line l1.

3 and 4 are views for explaining this connection relationship. FIG. 3 is a schematic configuration diagram showing a connection state of each device, and FIG. 4 is a diagram showing an arrangement of connection terminals of each device. Is. The charger 1 has a plug 1A for connecting an AC power source, and at the top,
It is provided with a mounting portion 1B (see FIG. 4) that allows a lithium battery and other different secondary batteries to be mounted. Further, the charger 1 has a structure in which the telephone 3 can be mounted while the battery to be charged is loaded, and the troublesomeness of removing the battery 2 to be charged from the telephone 3 each time the battery is charged is reduced.

The lithium battery has, for example, a trapezoidal shape in a side view, and is formed on the upper and lower surfaces of its mounting tip with terminals indicated by (1) to (4) shorted via the inside. The terminal is for ground (GND), the terminal is for a temperature sensor, the terminal is for positive electrode + terminal, the terminal is for battery capacity (large / small) determination, and the terminal is for serial transmission of data and parameters from the ROM 2A. For read / write (R / W). Phone 3
The connection terminals are formed at appropriate positions on the lower surface in an array corresponding to the terminals 1 to, and when the lithium battery 2 is loaded, the connection terminals are brought into contact with each other. Further, similarly, the connection terminals are also arranged correspondingly inside the mounting portion 1B of the charger 1, so that when the lithium battery 2 is mounted, the respective connection terminals come into contact with each other. In the case of a different type of battery different from the lithium battery 2, terminals are not formed because the ROM 2A is not provided inside, but other terminals are formed similarly to the lithium battery. Also, regardless of the type of battery with a small battery capacity, the terminals are separated from each other, but with a battery with a large capacity, the terminals are short-circuited and the battery capacity can be checked by checking the potential of the terminals. Can be determined.

Here, the memory map of the ROM 2A in the lithium battery 2 will be described. In the ROM 2A, data indicating lithium performance and parameters for charging are written in advance in a predetermined format corresponding to the address. For example, it is data showing each type of lithium battery, and other parameters will be shown below by way of example.

Vc (cut-off voltage): allowable voltage indicating an upper limit, 8.2 V or 8.4 V Vmin (lower limit voltage): minimum voltage at which quick charge control is possible Tmin (lower limit control temperature): eg 5 ° C. In the embodiment, -30 ° C. or lower can be measured) Tmax (cutoff temperature): Control upper limit temperature, for example, 4
5 ° C. Il (quick charge low current): lower limit current value in high speed (rapid) charging mode (however, except when starting charging as described later) Ih (quick charge high current): high speed (rapid) charging mode Addition value to the current Il td (full charge time): Time factor to be considered as full charge Is (full charge determination current): Current value to be considered as full charge after approaching full charge and shifting from constant current control to constant voltage control .

Next, the protection circuit for the lithium battery will be described with reference to FIG. As described above, the lithium battery has the GND terminal and the + terminal, and the cell Ce
1 and Ce2 are connected in series. Usually, a lithium battery is constructed by connecting two to a plurality of cells in series.

Further, the lithium battery has a protection circuit 20 inside.
Is provided. The protection circuit performs various protection functions as described later, but in particular, when a relatively large current (for example, 50 mA or more) for normal charging is suddenly supplied from the start of charging, the protection circuit operates. The charging current is prevented from flowing in. Therefore, in order to perform the charging operation without the protection circuit operating, and to release it when it is already in operation, do not allow the inrush current for normal charging to flow immediately from the start of charging. There is a need to.

The protection circuit 20 comprises an IC 21 for control and field effect transistors FET1 to FET3 as switch circuits connected in series to the cells Ce1 and Ce2, and each FET1 to FET3 has a diode D1 to D1 respectively.
3 are connected in parallel. The diode D1 is a cell Ce
Diodes D2 and D3 are connected in the forward direction with respect to 1, 2 and in the reverse direction. The parallel circuit 22 including a diode and a resistor provided in the + terminal is for limiting the current during discharge.

The FET1 is turned off when the battery voltage drops to prevent further discharge, and the FET2
Is turned off by the sudden inflow of a large current, and FE
T3 is turned off by an overvoltage, and such off control is performed by a switch signal output from the control IC 21 based on the taken-in voltages of the cells Ce1 and Ce2. In particular, the OFF control for the FET 2 corresponds to the operation of the protection circuit 20 in the present invention, and the control IC 21
When the charging current is maintained below 50 mA for a predetermined time, FET2 is released or deactivated.

FIGS. 6 to 8 show the circuits of the charging device according to the present invention in a divided form. This charging device includes a rectifying / smoothing circuit unit 11, a conversion circuit unit 12, a drive circuit unit 13, a stop current control circuit unit 14, a charging control circuit unit 15, a battery state detection circuit unit 16, and a battery ROM (R / W) circuit. A microcomputer (hereinafter, referred to as a microcomputer circuit) 10 that is configured by a unit 17, a temperature sensor circuit unit 18, and a display circuit unit 19 and integrally controls each of the circuit units is provided.

The microcomputer circuit 10 comprises a microcomputer μC1 having input / output terminals, a reference clock oscillator circuit OSC, and multistage (ladder) resistors R1 to R8, and is a program for performing charging processing and processing during access from the telephone 3. It is provided with a program ROM having a built-in memory, a RAM for temporarily storing processing data, and the like. Then, data is fetched from each input terminal, and a command signal is output from each output terminal in order to execute the processing based on the processing program by using a parameter for charging or a preliminary parameter. Further, in the program ROM, the ROM 2A in the battery to be charged 2 as described in FIG.
A program for determining whether to read a parameter from the battery, a program for creating a preliminary parameter when the parameter cannot be read, and a program for controlling the current that does not activate the protection circuit 20 in the battery 2 to be charged and releases the operating state. Equipped with.

The ROM 11 stores preliminary parameters in the ROM 2A.
Is an internal memory that is stored in advance in the same format as.
For example, the address value of each parameter and the number of bits of parameter data match. Since the preliminary parameters in the ROM 11 are used even when the battery 2 to be charged is a lithium battery but the parameters cannot be read from the ROM 2A, both the lithium battery and other batteries are used. On the other hand, it is necessary that the parameters are effective and within a proper range. For example, 9.1V for the cutoff voltage Vc, 4.4V for the lower limit voltage Vmin, and the same value for the cutoff temperature Tmax and the control lower limit temperature Tmin, respectively, are the rapid charging low current Il. On the other hand, a slightly large value is relatively low for the fast charging high current Ih, but a little long for the full charge time td due to the holding of the current Ih, for example 3 hours to 4 hours. Is set. Also, the ROM 11
Since the battery state detection circuit 16 can determine whether the battery capacity is large or small, preliminary parameters corresponding to the large capacity and the small capacity are written.

It should be noted that the ROM 11 may be replaced with a program for creating a spare parameter so that the spare parameter is created, or only the spare parameter of one capacity is stored and the result of the capacity determination is determined. According to the above, the other preliminary parameter may be created.

The resistance values of the multi-stage resistors R1 to R8 are sequentially 2
By arranging and arranging the doubled resistors, each stage is configured to correspond to a bit position. The output side of each resistor is connected to the terminal LC collectively. Therefore, by outputting high and low signals as bit information to the input side of each resistance of the microcomputer μC1, 256 levels of level voltage can be generated at the terminal LC in this embodiment. The output voltage of the terminal LC is used as a reference signal of the constant current control circuit 24 as will be described later, and one step has a current value, which is set to 5 mA in this embodiment. The number of resistance stages is determined in consideration of control accuracy in constant current or constant voltage control.

The rectifying / smoothing circuit section 11 rectifies and smoothes the commercial power source from the plug 1A. The input terminal has a fuse F, a Zener diode ZD11 for removing noise and surge, a resistor R11, a capacitor C11 and a choke. The rectifying bridge DB and the smoothing capacitor C12 are connected via the circuit composed of the coil Lc.

The conversion circuit section 12 includes a transformer T and rectifying diodes D21, D22, D23, and a secondary side constant voltage power supply generation circuit 121. The transformer T has a primary coil L1, a secondary coil L2 and a power supply coil L3 on the secondary side, and a drive coil L4.
The output side of the rectifying / smoothing circuit section 11 is connected to one end of the primary coil L1, and the other end side is connected to the drain of the FET 31 which is a switching transistor in the drive circuit section 13. Further, the diode D2 is provided at one end of the secondary coil L2.
1, D22 are connected in parallel in the same direction, and a smoothing capacitor C21 is connected to the output side thereof. With this configuration, the voltage induced across the secondary coil L2 is rectified and smoothed to generate a charging current, It is arranged to lead to the battery 2 to be charged. Further, one end of the power supply coil L3 is connected to the diode D2.
3 and the smoothing capacitor C22 are connected to the constant voltage power supply generation circuit 121 on the secondary side. At the terminal B of the constant voltage power supply generation circuit 121, for example, a constant voltage of 5V can be obtained.

By providing the power supply coil L3 in parallel with the secondary coil L2, when the voltage of the battery 2 to be charged is low, the induced voltage of the secondary coil L2 is pulled by the battery voltage to be lowered and a constant voltage power supply is generated. The constant voltage at the terminal B of the circuit 121 is prevented from being lowered, thereby ensuring the stable operation of the microcomputer circuit 10.

The drive circuit section 13 periodically turns the FET 31 on and off to switch the inflow current to the primary coil L1, and thereby the secondary coil L2 and other coils L3.
A voltage is induced in L4. The circuit in which the diode D31 is connected in series to the parallel circuit of the capacitor C31 and the resistor R31 is to improve the characteristics of the current flowing into the primary coil L1 and prevent the inflow of reverse current. Are connected in parallel. The source of the FET 31 is connected to the common line via the current detection resistor R32.

The starting resistor R33 is for starting the FET 31 by applying a voltage to the gate of the FET 31, and is connected between the positive electrode of the rectifying / smoothing circuit section 11 and the gate of the FET 31. A series circuit including a capacitor C32, a resistor R34, and a drive coil L4 is connected between the gate of the FET 31 and the common line to form a self-excited oscillation circuit. Then, the induced voltage of the drive coil L4 is FE
A resistor R35 is connected between the source of the FET 31 and the cathode of the Zener diode ZD31 while being applied to the gate of T31. This protects the gate of the FET 31 from being applied with a voltage higher than the Zener voltage Vz of the Zener diode ZD31.

Diode D32 and transistor Q31
Is a negative voltage generation circuit that charges the capacitor C33 to a negative voltage while the FET 31 is off, and is connected to both ends of the drive coil L4. Further, a discharging resistor R36 is connected in parallel to the capacitor C33.

The FET 31 is connected to both ends of the capacitor C32.
Control transistor Q32 that lowers the gate of the transistor to the off voltage, and the charge and F accumulated in the capacitor C32.
A control transistor Q33 for discharging the electric charge of the gate of ET31 is connected to each. That is, the collector of the control transistor Q32 has a capacitor C
32 and the resistor R34, the control transistor Q3
3 has its collector connected to the connection point between the capacitor C32 and the gate of the FET 31.

The control transistors Q32 and Q33 are also provided.
Is connected to the anode of the Zener diode ZD32 via resistors R37 and R38, respectively, and the cathode thereof is connected to the source of the FET 31. The emitters of the control transistors Q32 and Q33 are connected to the negative voltage side of the capacitor C33.

Further, a photocoupler PC forming a part of the constant current control circuit section 14 is interposed in the drive circuit section 13. That is, the phototransistor Qpc forming the photocoupler PC is connected between the base of the transistor Q31 and the common line, and the light emitting diode D is connected to the secondary side.
pc is provided.

Here, the operation of the above circuit configuration will be described. When the input power source is connected, the capacitor C32 is charged through the starting resistor R33, which causes the FET
A voltage is applied to the gate of 31 and the FET 31 starts to turn on. Therefore, a current flows through the primary coil L1 to induce a feedback voltage in the drive coil L4, the induced voltage rises with a time constant determined by the drive coil L4, the resistor R34, and the capacitor C32, and the gate voltage of the FET 31 rises.
The current flowing from the source of the FET 31 increases. Then, when the source current increases, the voltage across the resistor R32 increases and the Zener diode ZD32 turns on, a base current flows and both the control transistors Q32 and Q33 turn on, and the gate voltage of the FET 31 becomes the capacitor C3.
To a negative voltage of 3. At this time, by discharging the electric charge of the capacitor C33 by the control transistor Q32, the FET is combined with the control transistor Q33.
FET 31 is rapidly turned off as it removes the charge on the gate of 31.

After this, FET3 is passed through the starting resistor R33.
The voltage is applied again to the gate of 1, and the FET 31 is turned on. That is, the FET 31 repeats switching,
By this switching, electric power is induced in the secondary coil L22 and rectified to obtain a constant current.

The constant current control circuit section 14 controls the output current on the secondary side. In addition to the photocoupler PC, the control voltage generation circuit 141 and a detection resistor for generating a voltage according to the output current at both ends thereof. A monitor circuit 142 for detecting R41 and the output current is provided.

As described above, the present invention makes it possible to charge different types of batteries. However, unlike nickel type batteries, lithium batteries are protected by a protection circuit 20 when a rapid charging current is supplied at the start of charging. Is activated and charging cannot be performed. The constant current control circuit unit 14 is for generating a gradually increasing charging current so as to release the protection circuit 20 at the start of charging, and thereafter generating a constant current.

The charging current generated on the secondary side is configured to flow through the + terminal, the battery 2 to be charged and the GND terminal and further through the detection resistor R41.

The control voltage generation circuit 141 includes a detection resistor R41.
The control voltage for feedback is generated based on the voltage generated across the resistor R41 by the current flowing through the resistor R41. That is, the control voltage generation circuit 141 has the operational amplifier OP1, the voltage dividing resistors R42 and R43 that divide the voltage between the detection voltage and the power supply voltage are provided at the inverting input terminal, and the power supply output of the constant voltage power supply circuit 121 is provided at the non-inverting input terminal. Voltage dividing resistors R44 and R45 for dividing the power supply voltage from the terminal B to obtain a reference voltage are connected. Voltage dividing resistors R43 and R45 are connected to both ends of the detection resistor R41. Then, a voltage of a level corresponding to the voltage across the detection resistor R41 based on the reference voltage is output from the operational amplifier OP1, and this voltage is applied to the anode of the light emitting diode Dpc forming the photocoupler PC. .

The constant current control by the constant current control circuit section 14 is performed by the following operation. When the output current on the secondary side decreases and no voltage is output from the control voltage generation circuit 141, no current flows in the light emitting diode Dpc and the phototransistor Qpc does not turn on. Therefore, the transistor Q31 does not turn on, and the capacitor C33 is less likely to be charged to a negative voltage. Therefore, the ON time of the FET 31 becomes long and the output current increases. On the other hand, when the output current increases and a voltage is output from the control voltage generation circuit 141, a current flows through the light emitting diode Dpc and the phototransistor Qpc is turned on. Therefore, the transistor Q3
1 is turned on, and the capacitor C33 is charged to a more negative voltage. Therefore, the ON time of the FET 31 is shortened and the output current is reduced. The constant current control is performed by the negative feedback functioning in this way.

At the connection point of the voltage dividing resistors R44 and R45, for example, 640 ms from the LC terminal of the microcomputer circuit 10.
The reference voltage is variably controllable by applying a voltage of a predetermined level output at intervals of. When the reference voltage is changed, the negative feedback control is performed so that the input voltage to the non-inverting input terminal matches the reference voltage, so the output current on the secondary side can be adjusted to the required level according to the reference voltage. Become.

The monitor circuit 142 is the control voltage generating circuit 14.
This is for monitoring the suitability of the output current control according to the item 1. That is, the monitor circuit 142 has an operational amplifier OP2 as a differential amplifier, and its non-inverting input terminal is GND.
And the inverting input terminals are connected to both ends of the detection resistor R41. Then, a monitor voltage of a level corresponding to the voltage across the detection resistor R41 is output from the operational amplifier OP2, and this monitor voltage is guided to the IO terminal of the microcomputer μC1. The microcomputer μC1 compares the monitor voltage taken into the IO terminal with the desired monitor voltage indicated by the reference voltage output from the LC terminal. If they do not match, the voltages to the multistage resistors R1 to R8 are matched so that they match. The application is distributed and adjusted so that a monitor voltage that should be adjusted, that is, a predetermined secondary side output current can be obtained.

The charge control circuit section 15 is provided between the conversion circuit section 12 and the battery 2 to be charged, and supplies the output current on the secondary side to the battery 2 to be charged continuously or intermittently. In the charging control circuit unit 15, the emitter is the conversion circuit unit 12
On the output side of, the collector is connected to the + terminal, the base is connected to the cathode of the Zener diode ZD51, the collector is connected to the anode of the Zener diode ZD51 via the resistor R51, and the emitter is connected to GND. The base is C of the microcomputer circuit 10.
And a transistor Q52 connected to the H1 terminal.
Further, the CH1 terminal is pulled up by the constant voltage from the power supply output terminal B of the constant voltage power supply generation circuit 121 via the resistor R52, and the transistor Q52 is provided while the microcomputer μC1 outputs the high level signal to the CH1 terminal. Is turned on, whereby the transistor Q51 is turned on and the secondary side output signal is supplied to the battery 2 to be charged, while the transistor Q52 is turned off while the low level signal is output to the CH1 terminal. As a result, the transistor Q51 is turned off and the output signal on the secondary side is cut off. The intermittent charging of the battery 2 to be charged is performed by turning on and off the transistor Q51 in this manner. For the intermittent charging in this embodiment, for example, a cycle of 40 seconds is adopted and 2
A charging period of seconds (16 seconds) and a rest period of 38 seconds (24 seconds) are set. The average charging current in this case is 1/20 (2/5) of the current supplied during the charging period. Also,
The cycle, the charging period, and the rest period can be appropriately adjusted depending on the average current to be passed.

Further, the Zener diode ZD51 is connected to the base of the transistor Q51, and when the battery voltage is low, intermittent charging is performed to prevent the transistor Q51 from overheating, and the power supply coil L3.
Is maintained at a predetermined level so that a constant level power supply voltage can be obtained from the power supply output terminal B. For example, assuming that the output voltage of the secondary coil L2 is 5V and the battery voltage is 1V, the transistor Q51 outputs 4V.
As a result, a voltage drop of V occurs, which becomes a load and generates heat. Therefore, the Zener diode ZD51 is used to maintain the base voltage at the threshold level to prevent the transistor Q51 from generating heat.

The battery state detection circuit section 16 detects the capacity of the battery connected between the terminals. The battery state detection circuit section 16 is connected to the + terminal to detect the battery voltage, and is connected to the capacity determination terminal to determine the battery type. It is composed of a determination circuit. That is, the + terminal has the detection terminal V1 at the connection point of the voltage dividing resistors R61 and R62 via the resistor R63 and the capacitor C61, and the capacitance determining terminal has the voltage dividing resistor R6.
The determination terminal S1 is connected to the connection point of R4 and R65 via a resistor R66 and a capacitor C62. Charged battery 2
Has a structure in which terminals having a small capacity are electrically separated from each other, while terminals having a large capacity are electrically connected. Therefore, when the same voltage is detected at the terminals, it is judged as a large capacity type battery, and when no voltage output is obtained at the terminal, it is judged as a small capacity type battery.

In a nickel-based battery, the battery voltage is 4 V or more in a normal state, and in a lithium battery, it is 1 V or more. Further, a nickel-based battery can be rapidly charged even at 4 V or less, but a lithium battery cannot be rapidly charged at 1 V or less due to abnormal heat generation. Therefore, the charging current is controlled as described later according to the detected battery voltage.

The in-battery ROM (R / W) circuit 17 is connected to the terminals and is for reading out the parameters of the ROM 2A in the lithium battery. ROM (R /
W) Circuit 17 is a resistor R71 provided between the terminal and the ROM terminal of the microcomputer μC1, a Zener diode ZD71 provided between the terminal and GND, a constant voltage power supply generation circuit 1
The resistor R provided between the power supply output terminal B of 2 and the ROM terminal
72 and a power output terminal B and a diode D71 interposed between the terminals. Prior to charging, the microcomputer circuit 10 transmits address data designating an address in the ROM 2A, receives a parameter read from the corresponding address in the ROM 2A, and stores the parameter in an internal RAM.

If the microcomputer circuit 10 accesses the ROM 2A but does not receive any parameter data from the ROM 2A, or if no response data is obtained after repeating the access a predetermined number of times, the parameters can be read. If it is determined that the backup parameter has not been stored, the backup parameter is read out to the internal RAM so as to start charging using the backup parameter stored in the ROM 11 which is the internal memory. Furthermore, when charging is started with the preliminary parameters,
Even during charging, the ROM 2A is repeatedly accessed at a predetermined cycle, and if the parameter can be read by removing the cause of the unreadableness during that time, this parameter is updated to the internal RAM instead of the preliminary parameter, and charging is performed. Is controlled to continue using the original parameters.

The temperature sensor circuit section 18 detects the temperature of the battery 2 to be charged and also detects the mounting of the battery. A thermistor TH, which is a temperature-sensitive element generally used as a sensor, is connected between the corresponding terminals of the battery to be charged 2.

The temperature sensor circuit section 18 is connected to the GND terminal and the temperature sensor terminal, and a resistor R81 and capacitors C81 and C82 at both ends thereof are connected between the terminal and the detection terminal T1 of the microcomputer μC1. The terminal is connected to the power supply output terminal B of the constant voltage power supply generation circuit 12 via the resistor R82. Then, a current is made to flow from the power output terminal B to the thermistor TH via the resistor R82, and the divided voltage due to the resistance component of the thermistor TH at this time and the resistance component of the resistor R82 is applied to the detection terminal T1 as the detection voltage. It is output and guided to the microcomputer μC1.

The microcomputer circuit 10 measures the temperature information fetched from the detection terminal T1, that is, the temperature of the battery 2 to be charged, and if the temperature is in the range of 5 ° C. to 45 ° C., determines that the temperature is controllable. On the other hand, it is determined that the battery 2 to be charged is not mounted in a state where the current does not flow from the power output terminal B to the thermistor TH at −30 ° C. or lower.

The display circuit section 19 is for displaying the state of charge in a distinguishable manner by color, and has two colors, for example, red and green L.
It has a light emitting element in which the ED is integrally incorporated. In the display circuit section 19, transistors Q91 and Q92 having collectors connected to the power output terminal B of the constant voltage power generation circuit section 12 via current limiting resistors R91 and R92, respectively, are provided in parallel, and both emitters are GND. , And the GR and RE terminals from the microcomputer μC1 are connected to the respective bases and resistors R93 and R94.
It is connected to the power supply output terminal B via and is pulled up. The green (green) LED 91 is a transistor Q
Connected between the collector of 91 and GND, red (RED)
The LED 92 is connected between the collector of the transistor Q92 and GND.

The green LED 91 is turned on when the GR terminal is at the high level and the transistor Q91 is turned on, and turned off when the GR terminal is at the low level and the transistor Q91 is turned off.
The red LED 92 is turned on when the RE terminal is at a high level and the transistor Q92 is turned on, and turned off when the RE terminal is at a low level and the transistor Q92 is turned off. Also, green,
When both the red LEDs 91 and 92 are turned on, they are turned on in yellow (YELLOW). At this time, flashing can be performed by repeating high and low. The microcomputer μC1 outputs high and low signals to the GR terminal and RE terminal, respectively, so that red light is lit during charging, green light is lit when charging is completed, and yellow light flashes in other than normal state. Control.

Next, a basic charging operation will be described with reference to the time chart of FIG. When charging is started, a current for normal charging is supplied as shown by a broken line at the start of charging, or when the battery 2 to be charged is a lithium battery containing the protection circuit 20, the LC terminal of the microcomputer μC1. Then, the reference voltage is stepwise increased and output, and the charging current is gradually increased from 0 and the supply is controlled until at least the predetermined time required for releasing is exceeded. As a result, the protection circuit 20 is released when the battery 2 to be charged is a lithium battery, and charging is ensured without the protection circuit 20 operating. Then, the charging current is continuously increased, and the current is increased for a time during which normal charging is possible, and then the constant current control is performed.

The battery temperature T is detected by the thermistor TH,
The thermistor resistance decreases as the temperature rises, and the detection terminal T
The detection voltage at 1 decreases. The microcomputer μC1 converts the detected voltage to the temperature T (or remains the detected voltage), and increases the gradient ΔT / Δt from the temperature detected twice in succession.
To calculate. When the gradient ΔT / Δt reaches a predetermined level, it is determined that the battery is fully charged, the charging operation is terminated, and the battery voltage Vpeak at this time is fetched from the battery voltage input terminal V1 and stored. Further, the charging operation is restarted following the end of the charging operation. The charging current during the recharge is controlled so as to increase stepwise. In this way, by giving a gradient to the rising of the current and performing the gradual increase control, the battery voltage, which has been in the decreasing tendency, starts to increase again. Then, the value Vpe in which the battery voltage is stored
If it matches ak, the charging is completed. After this, the maintenance mode is entered.

In this way, once charging is completed,
The charging current is gradually increased again, and recharging is performed until the battery voltage rises and becomes equal to the voltage at the end of charging, so that the charging amount approaches the full charge as much as possible. By gradually increasing the current during recharging, the battery voltage continues to drop as it is or when a high-level current is suddenly supplied, and overcharging does not always match Vpeak. Is effectively prevented from becoming.

In the above embodiment, the end of the first charge is monitored by the temperature rising gradient, but the present invention is not limited to this.
When it is detected that the temperature gradient or the battery voltage rises just before full charge, the constant current control until then is switched to constant voltage control, and under this constant voltage control, as the charge current approaches full charge. Predetermined level (full charge discrimination current) Is
It may be determined that the charging is completed on the condition that the charge has decreased.

If the battery voltage is lower than the voltage close to the threshold level of the charge control circuit section 15 at the start of charging, intermittent charging or preliminary charging is performed to raise the battery voltage to the threshold level. After that, the heat transfer of the transistor Q1 of the charge control circuit section 15 is prevented and the power supply voltage level of the secondary side is secured by shifting to the quick charge.

Next, details of the charging operation will be described with reference to the flowcharts of FIGS. FIG.
0 and FIG. 11 show one flowchart divided. In the figure, among the lines that connect each step,
A two-dot chain line shows a lithium battery, a broken line shows a battery that cannot be distinguished from a lithium battery or a nickel-based battery, and a thin solid line shows a case common to both batteries.

This flowchart is started when the AC plug 1A is plugged into a commercial AC power source or a main switch (not shown) is turned on.

When the flow chart starts, first, ID
The mode is shifted to the LE mode, the charging current I is set to 0, all states are reset to OFF (step S2), and
The battery temperature T is measured. If the battery temperature T ≧ −30 ° C., it is determined that the battery 2 to be charged is mounted, and the process proceeds to step S4. In step S4, the battery voltage V
And the data of the battery temperature T are fetched. Also, myco μC
1 accesses the ROM 2A in the battery 2 to be charged, that is, an instruction to read the parameter is given, and it is determined whether or not the parameter can be read. Further, in this state, the LED 92 is turned on.

The battery temperature T is always checked thereafter, and if the battery temperature T is <-30 ° C. in any state (step), the process returns to step S2.

If the parameters can be read, it is determined that the battery 2 to be charged is a lithium battery, and the battery voltage V is the minimum level Vmi in the lithium battery.
Maximum level (cutoff voltage) above n (eg 1V)
When the battery temperature T is not higher than Vc and the battery temperature T is not lower than the minimum level Tmin and not higher than the maximum level Tmax, the mode is shifted to the rapid mode (step S6). In the lithium battery, if the detection voltage V is Vmin or less, the detection voltage V is detected as almost 0 because the protection circuit 20 is operating. On the other hand, if it exceeds Vmin, the protection circuit 20 is detected. Indicates that it is not in the activated state (in the released state).

On the other hand, if the parameters cannot be read, it is determined that the parameters cannot be read because of a battery other than the lithium battery or even with the lithium battery due to contact failure or the like. The battery voltage V is at the minimum level Vmin with respect to the preliminary parameters that satisfy both the conditions of 1 and the conditions of batteries other than lithium batteries.
(E.g. 4.4 V) or higher and maximum level Vmax or lower, and battery temperature T is minimum level Tmin or higher and maximum level Tmax
In the following cases, the mode is changed to the rapid mode (step S6).

If the battery temperature T is lower than Tmin (5 ° C. in the present embodiment) regardless of the type of battery, the trickle 1 is used.
In the mode (step S8), the battery voltage V is at the minimum level V
If it is less than min, the trickle 2 mode (step S1
In 0), if the battery temperature T exceeds Tmax (45 ° C. in this embodiment), the trickle 3 mode (step S12) is entered. Further, in the case of a lithium battery, the battery voltage V
Exceeds the cut-off voltage Vc, or if the battery cannot be identified as a lithium battery and the battery voltage V exceeds the cut-off voltage Vnc (> Vmax), the trickle 3 mode (step The process moves to S12).
This limit voltage Vnc corresponds to the cutoff voltage Vc of the lithium battery.

The rapid mode is for rapid charging and is designed to continuously supply a predetermined level of current. The trickle 1 mode to trickle 3 mode are all for recovering from a state out of the normal state. The trickle 1 mode raises the battery voltage to a level at which quick charge is possible, or a temporary abnormality in the rapid mode. For example, when the battery voltage V drops below Vmin or Vth due to a contact failure, a short circuit, a sensor abnormality, or the like, and when the battery temperature T falls below Tmin, so-called recovery charging is performed until the abnormality is released. It is for.
Trickle 2 mode is for raising the battery voltage to a level at which it can be rapidly charged, and for releasing the protection circuit 20 because it is a lithium battery and is activated. The trickle 3 mode is to stop the charging current and wait for the battery temperature or the battery temperature to drop to a level at which rapid charging is possible.

The charging operation will be described below for different cases. (1) When the Lithium Battery is Normally Charged When the rapid mode is changed from step S4 to step S6, the charging current I of Il + Ih (for example, about 1 A in total) is continuously supplied while maintaining this level. The monitor circuit 142 detects the charging current via the detection resistor after the reference voltage from the LC terminal is switched and controlled at a time interval of 640 ms, for example, and when the charging current deviates from the charging current according to the instruction at the LC terminal. To match this,
Fine adjustment of the reference voltage is performed. It should be noted that by detecting the voltage generated at both ends of the detection resistor R41 in advance without connecting the battery to be charged 2 to the secondary side and compensating for this amount as an offset amount, that is, by setting it in the microcomputer μC1, the detection accuracy can be improved. As a result, the accuracy of current control can be further improved.

During the rapid charging, it is judged whether or not the battery voltage V exceeds the cutoff voltage Vc (step S6).
1) If not exceeded, charging is continued as it is, and if it is exceeded, constant current control is switched to constant voltage control (step S62). As a result, the current gradually decreases as the charging progresses and approaches full charge, and the current value is 20 m.
When it reaches A (= Is), it is determined that the battery is fully charged, and the maintenance mode (step S16) is entered. In the maintenance mode, the current is set to 0, the LED 91 is turned on, and the charging is completed.

(2) When the battery to be charged is normally charged when the parameter cannot be read In this case, the charging control is performed using the preliminary parameter. Start charging in the same way as (1) above (Il + I
It is controlled by the microcomputer μC1 so that the charging current of h) is supplied. When the battery voltage V reaches the limit voltage Vsc (<Vnc) or the cutoff voltage Vnc during charging, it is determined that the battery is fully charged and the maintenance mode is entered. In the maintenance mode, a terminal current of a level that compensates for self-discharge is passed (step S16). Even after this, while the battery to be charged 2 is attached to the main charging device 1,
The battery voltage V is checked, and if the battery voltage V drops by, for example, 1 V, step S4 is performed to perform supplementary charging.
Move to

On the other hand, if the temperature rise ΔT / Δt reaches a predetermined value before the battery voltage V reaches each of the conditions for ending the charging, the battery voltage at this point is taken in as Vpeak and the top-off for recharging is performed. Mode (Step S1
Go to 4). In this top-off mode (recharge), the charging current I is increased stepwise from 0 to (Il + Ih). This stepwise current rise is caused by the LC of the microcomputer μC1.
This is done by sequentially increasing the reference voltage from the terminals.
In this way, by increasing the charging current from 0, the battery voltage will start to increase again. When the current value reaches (Il + Ih), the power is continuously supplied while maintaining this level. In this mode, the LED 91 is on. The current value in the top-off mode is (I
If it is equal to or lower than (l + Ih), it can be set to a predetermined level.

Further, the battery voltage V is detected during charging, and it is judged whether or not the stored voltage Vpeak has been exceeded (step S141). If not, while maintaining the current value at (Il + Ih). When the charging is continued (step S142) and V> Vpeak, the charging is completed and the maintenance mode (step S16) is entered.

In recharging in the top-off mode, when the total time from the start of charging in the rapid mode exceeds the full charge td, or the battery temperature T is Tmax.
When it exceeds, the battery is considered to be fully charged and charging is completed, and the mode shifts to maintenance mode.

(3) When shifting to trickle 3 mode from step S4 In the trickle 3 mode, charging is not started (I = 0) and LE is set.
Both D91 and LED92 are made to blink in synchronization (yellow flash). In this state, in the case of a lithium battery, it is determined whether the battery voltage V is (Vc-200 mV) or less and the battery temperature T is (Tmax-6 ° C.) or less, and recovery is performed, or the battery type is unknown. In the case of such a battery, it is determined whether the battery voltage V is (Vnc-200 mV) or less and the battery temperature T is (Tmax-6 ° C.) or less, and the recovery is made. If so, the mode is switched to the rapid mode. . In this case, if the normal state is not restored even after the lapse of a predetermined time, the process may return to step S2.

(4) Trickle 1 from steps S4 and S10
In the case of shifting to the mode In the trickle 1 mode, first, it is determined whether or not the battery voltage V is not more than the threshold voltage Vth + 50 mV (step S81). This threshold voltage Vth is Veb (voltage between the emitter and base of the transistor Q1) + Vz (zener diode ZD) in the charge control circuit 15.
The Zener voltage of 51) is set to 3.5 V in this embodiment.

If the battery voltage V is less than (Vth + 50 mV), in consideration of heat generation of the transistor Q1, intermittent charging is instructed (step S82), and if not, continuous (linear) charging is instructed (step S83). ). In both of the intermittent charging and the linear charging, the microcomputer μC1 controls the charging current to increase stepwise at the start of charging, thereby ensuring that the protection circuit 20 is released.

Next, it is judged whether or not the battery temperature T is lower than (Tmax + 1 ° C.) (step S84), and the battery temperature T
Is less than (Tmax + 1 ° C.), yellow flash is performed (step S85), and intermittent charging is started with a duty of 1, that is, for example, a charging time of 2 seconds and a rest period of 38 seconds and a cycle of 40 seconds (step). S86). If the battery voltage V is less than (Vth + 50 mV) and the battery temperature T is less than (Tmax + 1 ° C.), intermittent charging is continued. On the other hand, the battery temperature T rises (Tmin + 1
℃) or more, then the battery voltage V (Vmin + 5
It is determined whether the voltage is less than 0 mV (whether or not the protection circuit 20 has been released) (step S87). If the battery voltage V is less than (Vmin + 50 mV), it is not released, so yellow flash is performed (step S88,
S85), the intermittent charging with the duty 1 is continued. On the other hand, if the battery voltage V is (Vmin + 50 mV) or more, since it is confirmed that the battery voltage has been released, the LED 92 is turned on (step S89), and then the battery voltage V is (V
(th + 50 mV) or more is determined (step S90). Here, the battery voltage V is (Vth + 50
If it is less than mV), the battery voltage V was (Vmin + 50 mV) or more in step S87 for the time being. The intermittent charging is switched to (step S91).

On the other hand, when linear charging is started in step S83, similar processing is executed. The intermittent charging is performed by the high and low signals from the CH1 terminal of the microcomputer μC1, and the charging and rest periods are appropriately changed according to the battery temperature, the battery voltage and the threshold level (steps SS86, S91 and S83).

Then, the battery voltage V is (Vth + 50 m
When V) or more, it is considered that the level has reached a level at which rapid charging is possible, and the mode shifts to the rapid mode.

(5) When shifting to trickle 2 mode from step S4 Here, in the case of a lithium battery, the protection circuit 20
Is operating, trickle 2 to release it
It shifts to the mode.

In the trickle 2 mode, the charging current is 50 m
The current value is set to A, and this current value is monitored by the monitor circuit 142 and kept constant. At the start of the current supply, the current gradually changes from 0 to 50 mA, that is, 6 mA.
The current is controlled to increase for a time (predetermined time) required to reach 50 mA by increasing by 5 mA every 40 ms,
The release of the protection circuit 20 is secured. First, the battery voltage V
Is determined to be equal to or higher than the cutoff voltage Vc (step S101). If the battery voltage V is equal to or higher than the cutoff voltage Vc, the non-charge (non-charge) mode (step S1
Go to 8). If the battery voltage V is less than the cutoff voltage Vc, then it is determined whether the current value is 50 mA or more (step S102). If the current value is less than 50 mA, it is considered that the releasing operation is still in progress, and charging is repeated until it reaches 50 mA. If not, it is determined whether the battery temperature T exceeds Tmax (step S).
103). If the battery temperature T exceeds Tmax, the mode shifts to the trickle 3 mode, and if not, the mode shifts to trickle 2 mode.

On the other hand, when the mode is shifted to the non-charging mode from step S101, the charging is interrupted, and the battery voltage is Vmin to (Vc-200 m for the lithium battery during this period.
V), Vmin to (Vm
ax-200 mV), the process proceeds to step S4.

In the flow chart of the charging operation described above, when the parameters cannot be read, the microcomputer μC1 outputs the access code to the ROM terminal at regular, periodic or specific steps during charging control. When the parameters can be read from the ROM 2A at this time, the read original parameters can be used in place of the preliminary parameters. Appropriate charging control can be achieved.

Next, the operation of accessing the ROM 2A will be described with reference to the flowchart shown in FIG. When the battery 2 to be charged is attached, the charging device 1 sends an access signal from the ROM terminal to the ROM 2A to read the parameters. At this time, first, as shown in FIG. 2, it is determined whether or not the connected telephone 3 is being accessed to read data from the ROM 2A, that is, whether or not communication is in progress (step S201). If the microcomputer μC1 is accessing,
To return. On the other hand, if the telephone 3 is not accessing, the microcomputer μC1 indicates that the own priority is given to the telephone.
As shown to the side, a priority signal (code) is output (step S202), and thereafter, access for reading is started (step S203). As the code indicating the priority signal, a pattern code different from the address code, the parameter code or the data code is adopted so that the priority signal can be discriminated from other signals. in this way,
Since both the charging device 1 and the telephone 3 transmit a code promised in advance to secure the priority right, it is possible to prevent each other from reading erroneous data and parameters, and to secure high reliability of communication. ing.

Further, instead of the priority signal, if there is any level signal of high or low on the transmission line when accessing from the charging device 1, it is considered that the other device is accessing. Alternatively, the access may be waited for a predetermined time.

In this embodiment, in the rapid mode of step S4, the protection circuit 2 is already used in this mode.
Since it is considered that the release control for 0 has been completed,
Although the charging current of (Il + Ih) is supplied from the start of charging, the charging current I is increased by sequentially increasing the reference voltage from the LC terminal of the microcomputer μC1 as in the top-off mode (recharging) of step S14. From 0 to (Il +
Ih) may be stepped up,
By doing so, it is possible to prevent inadvertent operation of the protection circuit 20.

Further, the present invention can be applied to a secondary battery of the type having the protection circuit 20 inside.

Further, in the present embodiment, the telephone is described as another device, but the present invention is not limited to this, and the beard can operate with a secondary battery and read the characteristic data of the battery as needed. It is applicable to general battery-applied devices such as shaving machines and electric tools.

[0096]

As described above, according to the invention of claim 1, the switching means for changing the level of the charging current and the charging current for a predetermined time at a predetermined gradient at the start of charging are increased. The switching control means for activating the switching means to release the protection circuit in the battery to be charged is provided, so that the protection circuit of the battery to be charged is not activated (maintains the non-operation state) or is in the operation state. You can unlock the ones in (not unlocked). Further, by controlling the charging current at the start of charging, it is possible to charge various types of charged batteries universally regardless of the presence or absence of the protection circuit.

According to the second aspect of the present invention, since the increase of the charging current is increased stepwise from the 0 level by the switching control means, the current control by digital processing can be easily performed.

According to the third aspect of the invention, since the determination means for determining the release state of the protection circuit at the start of charging is provided, and the switch control means is operated when it is determined that the protection circuit has not been released, the switching control means is operated reliably. In addition, the charging operation is performed directly, and the charging operation is performed directly when in the cancellation state, so that quicker charging is possible.

According to the fourth aspect of the invention, since the release state of the protection circuit is originally determined by the voltage level of the battery to be charged connected to the charging device, there is no need to provide a separate structure. The battery voltage value can be obtained as it is.

According to the fifth aspect of the present invention, the charging current is increased for a predetermined time and then increased to the current value in the normal charging, which contributes to quick charging.

According to the sixth aspect of the invention, when the charging current is increased for a predetermined time, a confirmation means for confirming the release of the protection circuit is provided, and if the release is confirmed, the normal charging is started. As a result, reliable normal charging is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a relationship between a charger including a charging device according to the present invention and a battery to be charged that is charged by the charger.

FIG. 2 is a configuration diagram showing an example of a connection mode of a charger to which the charging device according to the present invention is applied.

FIG. 3 is a schematic configuration diagram showing a connection state of each device.

FIG. 4 is a diagram showing an arrangement of connection terminals of each device.

FIG. 5 is a circuit diagram illustrating a protection circuit for a lithium battery.

FIG. 6 is a circuit diagram of a charging device according to the present invention.

FIG. 7 is a circuit diagram of a charging device according to the present invention.

FIG. 8 is a circuit diagram of a charging device according to the present invention.

FIG. 9 is a time chart illustrating a basic charging operation.

FIG. 10 is a flowchart illustrating a charging operation.

FIG. 11 is a flowchart illustrating a charging operation.

FIG. 12 is a flowchart illustrating an operation of accessing a ROM.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging device 2 Battery to be charged 2 A ROM 3 Telephone 10 Memory circuit 101 Multi-stage switching circuit 102 Switching control means 11 Rectification smoothing circuit section 12 Conversion circuit section 13 Driving circuit section 14 Constant current control circuit section 15 Charging control circuit section 16 Battery state detection Circuit part 17 ROM (R / W) circuit part in battery 18 Temperature sensor circuit part 19 Display circuit part 20 Protection circuit

Claims (6)

[Claims] 1. A charging device for charging a battery to be charged, which has a protection circuit which is activated when a rapid change in the charging current is detected to shut off current supply to the battery to be charged, wherein the level of the charging current can be changed. And a switching control unit that operates the switching unit to increase the charging current for a predetermined time at a predetermined gradient at the start of charging. 2. The switching means allows the charging current to be switched stepwise, and the switching control means increases the charging current stepwise from 0 level. The charging device according to claim 1. 3. The charging device according to claim 1 or 2, further comprising a determination means for determining a release state of the protection circuit at the start of charging, and when it is determined that the protection circuit is not released, the switching control means is operated. Charging device characterized in that it is adapted to. 4. The charging device according to claim 3, wherein the determination means determines the voltage level of the battery to be charged. 5. The switching control means raises the charging current for the predetermined time and then raises it to the current value in normal charging. The charging device described. 6. The charging device according to any one of claims 1 to 5, further comprising confirmation means for confirming the release of the protection circuit when the charging current is increased for the predetermined time, and the release is confirmed. And a charging device, which is adapted to shift to normal charging.