CN1688075A

CN1688075A - Charging device for cell and method thereof

Info

Publication number: CN1688075A
Application number: CN 200510074381
Authority: CN
Inventors: 韦景川
Original assignee: E Ten Information Systems Co Ltd
Current assignee: E Ten Information Systems Co Ltd
Priority date: 2005-05-26
Filing date: 2005-05-26
Publication date: 2005-10-26
Anticipated expiration: 2025-05-26
Also published as: CN100384051C

Abstract

This invention relates to a charge device for a battery and a method. Said charge device is connected with a power supply for providing power needed by charging the battery including a counting unit, a pulse generation unit and a control unit, among which, said charging method utilizes the pulse signal generated by said pulse generation unit to control the frequency of a counting signal of the unit and the control unit controls the charging current supplied by the power supply based on the counting state of the signal, that is to say providing a fine current to charge the battery first, then increasing the current steadily till the counting signal does not change.

Description

The charging device of battery and method

Technical field

The invention relates to a kind of charging device and method of battery, refer in particular to and a kind ofly control the size of charging current, reach the device and method of finishing battery charge with the charging modes that battery is slowly increased by little electric current by count signal.

Background technology

The classification of current battery has a variety of, the not chargeable battery that uses up with regard to throwing away is called primary cell in chemical cell, the reusable battery that can repeatedly charge again is called secondary cell, the process that this secondary cell can see through charging make in the battery active material once again be returned to original state, thereby can provide electric power once again; Wherein the voltage of secondary cell battery in charging process can rise gradually along with the increase that stores electric weight, when the electric weight of battery storage reaches capacity electrode material can't continue to charge the time, promptly finishes charging; Battery voltage in discharge process can continue to descend at leisure, just stops the position surely if the then voltage rising at once that temporarily stops to discharge in the process is returned to certain, and voltage begins from this standard position again to descend if continue to discharge then again.

And often be used in some portable electric devices with lithium battery in the secondary cell commonly used, for example: mobile phone, PDA or the like, the material composition aspect of lithium secondary battery wherein, be to be divided into positive electrode, negative material, electrolyte and barrier film etc., though and in charging process if can be apace to the battery full charging with large current charge, but also can improve the temperature of battery, and this battery might take place to have filled full but voltage does not but reach the accurate position of setting as yet, and the situation that causes battery to overcharge takes place, therefore, the voltage of battery is from the machinery and the chemical constitution of battery, stable low current charge can charge completely and do not injure active material in the battery, make accumulator property, life-span can both remain on perfect condition, and shortcoming is that the charging interval is long, and this is not that the institute of industry and commerce social condition now is receptible.

Therefore, studying new charging technique, is very important to save the charging interval and to take into account keeping of battery useful life.

Summary of the invention

Deficiency in view of existing secondary cell charge technology the purpose of this invention is to provide a kind of " charging device of battery and method that can address the above problem.」

So the charging device of battery of the present invention is the power supply that connection one provides the electric power of battery charge, it comprises: one provides the counting unit of count signal; One the pulse generation unit of count frequency in order to the control count signal; An and control unit of controlling charging current according to the change in count of count signal.

Wherein control unit has the switch module and the impedance component of plural groups, and according to the numerical value change of this count signal to control the unlatching and the closed action of the pairing a plurality of switch modules of this count signal; Therefore can control this power supply by the resistance of the impedance component of the corresponding connection of action and this each switch module institute of these a plurality of switch modules provides a charging current to charge to this battery.

In addition, charging device more comprises a current limliting unit, in order to provide this power supply output stable charging current.Wherein this current limliting unit has a bleeder circuit and a comparison circuit, this bleeder circuit provides the anode and the negative terminal voltage signal of this comparison circuit respectively, as it is unstable and when causing positive terminal voltage that this bleeder circuit inputs to comparison circuit greater than negative terminal voltage that charging current takes place, promptly the reset count signal of this counter, this count signal is counted again, and then change the initiation of charge state that charging current is returned to little electric current, after slowly increase its charging current again along with the counting of count signal.

The present invention also discloses a kind of method for charging batteries, is the step of battery being charged by the power supply that charging device connects, and it comprises:

The pulse signal of the count frequency of one this count signal of control is provided;

According to the numerical value change of this count signal to control the action of the pairing a plurality of switch modules of this count signal; And

According to the resistance of the impedance component of the action of this a plurality of switch modules and the correspondence connection of this each switch module institute, to control the size of current of this power supply to battery charge.

Wherein, more comprise one the charging current instability step of count signal of promptly resetting takes place, count signal is counted again, and then is changed the initiation of charge state that charging current is returned to little electric current, after slowly increase its charging current again along with the counting of count signal.

Description of drawings

Fig. 1 is the circuit block diagram of charging device preferred embodiment of the present invention;

Fig. 2 is the circuit diagram of charging device preferred embodiment of the present invention;

Fig. 3 is the charging and discharging curve schematic diagram of charging device preferred embodiment of the present invention;

Fig. 4 is the flow chart of charging method preferred embodiment of the present invention.

Embodiment

See also Fig. 1, shown in Figure 2, be respectively the composition calcspar and the circuit diagram of battery charger preferred embodiment of the present invention.As shown in the figure, present embodiment battery charger 1 connects a battery 2 to be charged respectively, and one provides the power supply 3 of these battery 2 charging currents, and mainly has a counting unit 11, a pulse generation unit 12, a control unit 13 and a current limliting unit 14.

Counting unit 11 is in order to providing a count signal, and count signal is to adopt binary mode to count; Wherein counting unit 11 is to be one or four digit counter U2 in the present embodiment, the output signal of counter U2 is QA, QB, QC and QD, and QA is lowest order, QD is highest order, the scope of its counting is 0000 to 1111 (be equivalent to 10 systems 0 to 15), change and have 2 biquadratic, promptly 0000,0001 ..., 16 kinds of variations such as 1110,1111; So also can be the counter of other figure place in other alternate embodiment, and not as limit.

Pulse generation unit 12 provides a pulse signal, in order to the count frequency of count signal of control counting unit 11; Pulse generation unit 12 mainly comprises an oscillator U1, a resistance R 5 and a capacitor C 1 in the present embodiment, wherein oscillator U1 has an output and an input, the parallel resistance R5 of this oscillator U1 elder generation, its input be ground connection behind the series capacitance C1 again, and output then directly connects this counting unit 11.

Control unit 13 is controlled in order to the switch of supplying the charging current size of batteries 2 as power supply 3, in present embodiment, include four groups switch module 131 and impedance component 132, wherein these four groups of switch modules 131 are four MOS switch Q1-Q4, and 132 of this impedance components comprise each MOS switch Q1-Q4 the resistance R 1-R4 that connects respectively; Wherein control unit 13 is that numerical value change according to the count signal of four digit counter U2 is to control unlatching and the closed action of pairing four the MOS switch Q1-Q4 of this count signal, and control 3 pairs of these batteries 2 of power supply by the resistance of the resistance R 1-R4 of the corresponding connection of each MOS switch Q1-Q4 institute and provide a charging current that increases progressively gradually to charge, and the magnitude relationship of its resistance is set at R1＞R2＞R3＞R4 in present embodiment.In addition, change in the example in other, the quantity of switch module 131 is not exceeded with four, and also available other switch module replaces, and the quantity of its switch module 131 can be depending on the output figure place of counter U2, as: the 8-digit device then needs eight switch modules.

In the present embodiment, current limliting unit 14 is in order to provide power supply 3 outputs stable charging current, this current limliting unit 14 has a bleeder circuit 141 and a comparison circuit 142, and this bleeder circuit 141 is to comprise 5 resistance R 6, R7, R8, R9, R11 in the present embodiment, in order to anode (+) and negative terminal (-) voltage signal of power supply 3 dividing potential drops so that this comparison circuit 142 to be provided respectively, and 142 of comparison circuits comprise a comparator U3; Resistance R 8 is the very little resistance of a resistance in the present embodiment, makes between A end points among the figure and B end points voltage (VA and VB) only have a slight voltage difference and exists; In addition, negative terminal (-) voltage signal that is preset as comparator U3 on the circuit design in the present embodiment can be greater than anode (+) voltage signal, promptly must be greater than the voltage on the resistance R 7 at the voltage on the resistance R 11, and make comparator U3 can export the CLR end of a Lo signal to counter U2, because the CLR end is the action of Hi signal triggering, so the current potential that can avoid comparator U3 to produce a Hi transfers to the CLR pin of counter U2, and cause count signal constantly to count again.

Moreover, when producing a big electric current if power supply 3 output charging currents (I) are unstable (as: charging current moment increase), though resistance R 8 is the very little resistance of a resistance, but because the electric current that passes through rises, therefore, still can between terminal A and terminal B, produce a voltage, and make the pressure reduction between VA and VB increase, and in case when causing anode (+) voltage that this bleeder circuit 141 inputs to comparison circuit 142 greater than negative terminal (-) voltage, comparator U3 promptly sends a reset signal (RESET) to counter U2, again count to remove (clear) original count signal, at this moment, the charging current of battery 2 is returned to the initiation of charge state of little electric current, slowly increase its charging current (I) afterwards again along with the counting of count signal, so this current limliting unit 14 has the unsettled function of the charging current of preventing (I), and can provide power supply 3 outputs stable charging current (I).

See also shown in Figure 2, TP1 among the figure and TP2 are for just connecting battery 2 respectively, negative pole, when power supply 3 provides a charging current (I) that battery 2 is charged, this counter U2 can begin counting, in the present embodiment, resistance R 9 and R11 in design its resistance value much larger than the resistance value of resistance R 1～R4, therefore, can be at the current value on resistance R 9 and the R11 much smaller than the current value on resistance R 1～R4, so behind the current value of ignoring on R9 and the R11, can obtain charging current (I)=supply voltage (VCC)/(R8+R), wherein total resistance R is the resistance value after resistance R 1～R4 parallel connection, and its resistance is neglected MOS switch Q1～Q4 conducting greatly and decided;

For example: the count signal of counter U2 is 0001 o'clock, only have only the signal of a Hi of QA output to be sent to the MOS switch Q1 (for the Hi conducting) that is connected, i.e. the MOS switch Q1 conducting (short circuit ground connection) that connected of QA output and and

power supply

3 and 2 on battery form a charge circuit; Therefore, the resistance value of total resistance R is the resistance value of resistance R 1, i.e. R=R1, and charging current (I)=supply voltage (VCC)/(R8+R1).

When count signal is 0010, only have only the signal of a Hi of QB output to be sent to the MOS switch Q2 that is connected, i.e. the MOS switch Q2 conducting that connected of QB output, and and

power supply

3 and 2 on battery form a charge circuit; Therefore, R=R2, charging current (I)=supply voltage (VCC)/(R8+R2); And because R2＜R1, so the resistance value of total resistance R descends, charging current (I) has then risen.

When count signal became 0011, the signal that promptly has QA and QB to export a Hi respectively was sent to MOS switch Q1, the Q2 that is connected, promptly QA and QB output the MOS switch Q1 and the Q2 conducting that connect respectively, and and

power supply

3 and 2 on battery all form charge circuit; Therefore, the resistance value of total resistance R is the resistance value after resistance R 1 and resistance R 2 parallel connections, i.e. R=(R1*R2)/(R1+R2), and R＜R2＜R1, so the resistance R after parallel connection has diminished, but charging current (I) becomes big relatively.

Last as: during rolling counters forward to 1111, the signal that promptly has QA, QB, QC and QD to export a Hi respectively is sent to MOS switch Q1, Q2, Q3 and the Q4 that is connected, and make this MOS switch Q1, Q2, Q3 and Q4 conducting, and all and 3 on power supply 2 and battery form a charge circuit; At this moment, the resistance value of total resistance R is the resistance value after resistance R 1, R2, R3 and the R4 parallel connection, i.e. R=(R1//R2//R3//R4), and charging current (I)=supply voltage (VCC)/(R8+ (R1//R2//R3//R4)); So the total resistance R after parallel connection is minimum, but charging current is maximum relatively; As seen, the size of charging current (I) depends on count signal.

Moreover, the charging voltage (Vcc) of establishing power supply 3 in the present embodiment is that 0.2 Ω (small resistor), resistance R 1 are that 100 Ω, resistance R 2 are that 50 Ω, resistance R 3 are that 10 Ω and resistance R 4 are 1 Ω for 5V, resistance R 8, wherein count up at count signal at 1111 o'clock by 0000, its count signal and charging current relation are as shown in the table:

Table 1

Count signal	Resistance R	Charging current	Count signal	Resistance R	Charging current
Count signal	Resistance R	Charging current	Count signal	Resistance R	Charging current	????0000	????0Ω	????0A	??0001	????100Ω	??0.050A
????0010	????50Ω	????0.100A	??0011	????33.3Ω	??0.149A	????0000	????0Ω	????0A	??0001	????100Ω	??0.050A
????0010	????50Ω	????0.100A	??0011	????33.3Ω	??0.149A	????0100	????10Ω	????0.490A	??0101	????9.1Ω	??0.538A
????0110	????8.3Ω	????0.588A	??0111	????7.69Ω	??0.634A	????0100	????10Ω	????0.490A	??0101	????9.1Ω	??0.538A
????0110	????8.3Ω	????0.588A	??0111	????7.69Ω	??0.634A	????1000	????1Ω	????2.5A	??1001	????0.99Ω	??2.513A
????1010	????0.98Ω	????2.525A	??1011	????0.97Ω	??2.538A	????1000	????1Ω	????2.5A	??1001	????0.99Ω	??2.513A
????1010	????0.98Ω	????2.525A	??1011	????0.97Ω	??2.538A	????1100	????0.91Ω	????2.618A	??1101	????0.90Ω	??2.632A
????1110	????0.89Ω	????2.646A	??1111	????0.88Ω	??2.660A	????1100	????0.91Ω	????2.618A	??1101	????0.90Ω	??2.632A

Can learn by table 1, constantly count under the change at count signal, the resistance value of its total resistance R is along with reducing gradually, its charging current then is gradually in increase, when count signal stops to count, promptly keep last current value with battery 2 is continued to charge to saturated till, its charging curve is as shown in Figure 3.

Please consult Fig. 2 and cooperation table 1 more as can be known, charging current (I) is under the control of count signal, the highest 3A that is no more than, therefore, charging current is example with 3A, in addition, if charging voltage is 5V, resistance R 8 is that 0.2 Ω, resistance R 6 are that 56K Ω and resistance R 11 are 680K Ω for 180K Ω, resistance R 7 for 680K Ω, resistance R 9, wherein VA is 5V, and the voltage that can obtain on the resistance R 8 is 3A*0.2 Ω=0.6V, and obtains VB=4.6V; Other obtains:

Voltage=VA*R7/ on the resistance R 7 (R7+R6)=5*680K/ (680K+180K)=3.95V;

Voltage=VB*R11/ on the resistance R 11 (R11+R9)=4.4*680K/ (680K+56K)=4.07V;

Therefore, the voltage that can obtain on the voltage ratio resistance R 7 on the resistance R 11 is big; And comparator U3 negative terminal (-) voltage of connection resistance R 11 is greater than anode (+) voltage that connects resistance R 7, make comparator U3 can export the CLR end of a Lo signal to counter U2, because the CLR end is the action of Hi signal triggering, so, the action of removing count signal do not done this moment.

If when charging current (I) instability and moment when strengthening is example with 4A at this, be 4A*0.2 Ω=0.8V at the voltage that can obtain under above-mentioned the same terms on the resistance R 8, and obtain VB=4.2V; Other obtains:

Voltage=VA*R7/ on the resistance R 7 (R7+R6)=5*680K/ (680K+180K)=3.95V;

Voltage=VB*R11/ on the resistance R 11 (R11+R9)=4.2*680K/ (680K+56K)=3.88V;

Therefore, the voltage that can obtain on the voltage ratio resistance R 11 on the resistance R 7 is big; And comparator U3 negative terminal (-) voltage of connection resistance R 11 is less than anode (+) voltage that connects resistance R 7, make comparator U3 can export the CLR end of a Hi signal to counter U2, at this moment, the CLR end can be removed (clear) original count signal and count again, the charging current of battery 2 then reverts to the charged state of lower primary school electric current, slowly increase its charging current afterwards again along with the counting of count signal, so this current limliting unit 14 has the unsettled function of the charging current of preventing, and can provide power supply 3 outputs stable charging current.

As shown in Figure 4, the present invention more provides a kind of method for charging batteries, charges in order to control 3 pairs one batteries 2 of a power supply, and it comprises following step:

Step 401 a: count signal is provided;

Step 402: the pulse signal that the count frequency of a control count signal is provided.

Step 403: when this count signal begins counting, promptly control the unlatching and the closed action of the pairing a plurality of switch modules 131 of this count signal, make this power supply 3 provide a little electric current that this battery 2 is begun to charge;

Step 404: with the action of these a plurality of switch modules 131, reach the resistance that cooperates 131 corresponding impedance components 132 that connect of each switch module, continue to increase the magnitude of current of charging;

Step 405:, promptly this battery 2 is bestowed the fixed current amount and charge, till finishing charging when count signal stops counting.

Wherein, more comprise one unstable the and charge protection method of the count signal of resetting when causing the momentary charge electric current to increase of power supply 3 takes place, its step comprises:

See through 5 impedance components 132 (resistance R 8, R6, R7, R9 and R11) power supply 3 of charging is obtained first voltage signal and second voltage signal in the dividing potential drop mode, and respectively as the input voltage signal of this comparator U3 anode and negative terminal.

Utilize a comparator U3 to judge that whether first voltage signal of its input is greater than second voltage signal; If be, then by the output of this comparator U3 export a signal to counter U2 keeping the count status of former count signal, and continue to provide one to be the charging current that increases progressively to this battery 2;

Otherwise, then by the output of this comparator U3 export a signal to counter U2 with this count signal of resetting, and this count signal is counted again, and then changed the initiation of charge state that charging current is returned to little electric current, slowly increase its charging current afterwards again along with the counting of count signal.

But the above person; it only is a preferred embodiment of the present invention; be not to be used for limiting scope of the invention process; such as the equalization of doing according to the described shape of the present patent application claim, structure, feature and spirit changes and modifies, and all should be included in the claim protection range of the present invention.

Claims

1, a kind of battery charger is the power supply that connection one provides the electric power of battery charge, it is characterized in that, comprising:

One counting unit provides a count signal;

One pulse generation unit provides a pulse signal, in order to control the count frequency of this count signal;

One control unit, switch module and impedance component with plural groups, and according to the numerical value change of this count signal to control the unlatching and the closed action of the pairing a plurality of switch modules of this count signal; And by the action of these a plurality of switch modules and this each switch module the resistance of the corresponding impedance component that connects control this power supply and provide a charging current to charge this battery.

2, battery charger as claimed in claim 1 is characterized in that, described this counting unit is counter.

3, battery charger as claimed in claim 1 is characterized in that, described this count signal is a binary system.

4, battery charger as claimed in claim 1 is characterized in that, described this pulse generation unit comprises an oscillator.

5, battery charger as claimed in claim 1 is characterized in that, described this switch module is the MOS switch.

6, battery charger as claimed in claim 1 is characterized in that, described this impedance component is a resistance.

7, battery charger as claimed in claim 1, it is characterized in that, it more comprises a current limliting unit, this current limliting unit has a bleeder circuit and a comparison circuit, this bleeder circuit provides the anode and the negative terminal voltage signal of this comparison circuit respectively, then in order to relatively this anode and negative terminal voltage signal, whether its result who relatively exports resets as the count signal of judging this counter this comparison circuit.

8, battery charger as claimed in claim 7 is characterized in that, described this comparison circuit comprises a comparator.

9, a kind of method for charging batteries charges to a battery in order to control a power supply, it is characterized in that, comprises following step:

One count signal is provided;

Control the counting of this count signal;

When this count signal begin the counting, promptly controlling this power supply provides a little electric current that this battery is begun to charge;

With the numerical value change of count signal, continue to increase the magnitude of current of charging;

When count signal stops counting, promptly this battery is bestowed the fixed current amount and charge, until this battery is finished charging.

10, method for charging batteries as claimed in claim 9 is characterized in that, it more comprises the pulse signal of the count frequency that this count signal of control is provided.

11, method for charging batteries as claimed in claim 9 is characterized in that, the charging current that described this power supply offers this battery is to utilize the unlatching and the closed action control of a plurality of switch modules.

12, method for charging batteries as claimed in claim 11 is characterized in that, the unlatching of described these a plurality of switch modules and closed action are the numerical value change control according to pairing this count signal counting of each switch module.

13, method for charging batteries as claimed in claim 9 is characterized in that, described this power supply is to utilize the resistance size control of a plurality of impedance components to the magnitude of current size of this battery charge.

14, method for charging batteries as claimed in claim 9 is characterized in that, described this count signal is to adopt the binary numeral mode to count.

15, method for charging batteries as claimed in claim 9 is characterized in that, wherein more comprises a charge protection method of resetting count signal when causing the momentary charge electric current to increase because of power supply is unstable, and its step comprises:

First voltage signal and second voltage signal are provided;

Judge that whether this first voltage signal is greater than second voltage signal; If be, keep the count status of former count signal; Otherwise, this count signal of then resetting, and this count signal is counted again.

16, method for charging batteries as claimed in claim 15, it is characterized in that, described this first voltage signal and second voltage signal are to see through a plurality of impedance components the power supply dividing potential drop of charging is obtained, with respectively as the input voltage signal of this comparator anode and negative terminal.

17, method for charging batteries as claimed in claim 16 is characterized in that, it utilizes a comparator to judge the size of two groups of voltage signals of its anode and negative terminal input, the control signal whether its result who relatively exports resets as count signal.