GB2237696A - Fast charger for sealed nickel-cadmium batteries - Google Patents

Abstract

Intermittent constant current charging pulses t2c are applied to a battery until its voltage is sensed to be decreasing continuously. The cycle of pulses is then terminated. Voltage sensing is effected during each charging pulse. A first cycle may commence with a period T1 of relatively short and frequent charging pulses t1c, Subsequent cycles of charging pulses may each commence a predetermined period T3 after the previous cycle, there being fewer short pulses t4c in each such subsequent cycle than in the first. The charging current may correspond to a 3c rate, each main pulse t2c, t5c having a 10 second duration. If the duration, T2 or T5, of the main pulses part of a cycle exceeds a predetermined period before a voltage decrease is sensed, that cycle is terminated. Checks are also made that the battery voltage is within a predetermined range, and for open circuit, short circuit and wrong polarity. A plurality of batteries (281), (282), (Figs 20, 21), may be charged simultaneously by respective constant current circuits (287), (288) operating in sequence so that the respective charging cycles are simultaneous but the charging pulses are interleaved. <IMAGE>

Description

"BATTERY CHARGING DEVICE AND METH0D" BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a battery charging device and more particularly to a sealed nickel-cadmium cylindrical rechargeable cell/ battery pack; it uses a fast charging method with digital auto control for charging battery, testing battery, sensing battery voltage and avoiding the increase of cell temperature and internal pressure while charging.

2. Brief Description of the Prior Art Due to the facts of technological advancement in the field of micro sciences, material sciences, there are quite a number of small-ce3.l operated electronical components and products in the market. Further, the new electronical inventions creat a new territory for the application of small cell. As a result, there are various kind of cell being researched, invented for all kind of purposes; especially, the demend of compact-size, large-capacity, cell is even greater.

However, there is an inevitable drawback of cell; for instance, primary cell becomes a waste after its capacity runs out. It is not economical and it would cause pollution problem.

Therefore, the demand of secondary cell has increased tremendously.

Comparing the price, life and capacity of the secondary cell, we have come to the conclusion that among various kind of cells in the market, the nickel-cadmium cell stands out as the most efficient and economical one. And among all kind of nickel-cadmium cells, the sealed nickel-cadmium cylindrical rechargeable cell (refer to as sealed Ni-Cd cell below) is deemed the most acceptable and useful one for industrial and commercial purpose. However, there is one weakness of the sealed Ni-Cd cell, i.e., the problem of time required for recharging. Also, the imporper procedure of recharging may result in shortage of its life.

The nature and characteristics of the sealed Ni-Cd cell: In prior art, reference may be made to (1). "Nickel-Cadmium Battery Application Handbook" third edition published in 1986 by General Electric Company; in that book, the following portions may be referred to for further details, i.e., Page 2-3 to Page 2-5 ... Nickel-Cadmium Cell Chemistry; Page 2-5 to Page 2-8 ... Sealed Nickel Cadmium Cells; Page 3-2 to Page 3-7 ... Charging Efficiency; Page 3-8 to Page 3-10 ... Cell Pressure, Temperature and Voltage Interrelationships; Page 3-10 to Page 3-17 ... Overcharge; Page 5-7 to Page 5-11 ... Use Factors Affecting Battery Life; Page 5-11 to Page 5-12 ... Effect of Cell Construction on Battery Life; Page 5-17 to Page 5-19 ... Storage.

(2). "Alkaline Storage Batteries" published in 1968 by John Wiley & Sons, Inc.; in that book, the following portions may be referred to for further details, i.e., Page 197 to Page 217 ... Sealed Nickel Cadmium Sintered Type Batteries; Page 379 to Page 391 ... Discharge Characteristica; Page 391 to Page 392 ... Internal Resistance; Page 392 to Page 398 ... Charge Characteristics; Page 398 to Page 402 ... AH and WH Efficiency; Page 402 to Page 404 ... Charge Retention; Page 404 to Page 406 ... Life.

Several conventional charging methods are described as follows: (1). Standard charging: This method uses a current of 1/10 of the cell standard capacity (i.e., a charge rate of 0.1C, where the C rate is defined as the rate in amperes or milliamperes numerically equal to the capacity rating of the cell, which is given in ampere-hours or milliampere-hours.) to charge the cell constineously. When cell temperature is between 0 C and 25 C, in order to reach 100% nominal capacity, it takes an input of excess nominal capacity of 160%. That is, over 60% of capacity are lost during this method. If we explain this process in terms of hours involved, it takes 6 more hours than the ideal effective 10 hours to reach 100% capacity.

Therefore, this charge method has a drawback; it takes longer time, but has lower efficiency. The cell will deteriorate it's capacity through this method.

(2). Quick charging: Charging cell with rate of 0.2C - 0.3C.

This method takes shorter time than standard charging method, and it does not require other controls. Consequently, the internal pressure and cell temperature will increase rapidly; it results in low effective rate, and takes more capacity input, and consequently, cell's life would be reduced.

(3). Set-time fast charging: Charging cell with 1C or higher rate in a set-time method. Although it takes less time than the aforesaid two methods, it will creat high temperature and high pressure to affect cell's life and feature. Further, if it is handled by non-specialist to be unable to detect its remaining capacity, this method will result in overcharging or even damaging the cell.

(4). Voltage-setting charging: Pre-set a final charging voltage between the charger and the cell; when the pre-set voltage is reached, the charging input will be turned off. The drawback of this method includes a lot of factors: quality, brand, cell temperature, producing procedure, environmental temperature, number of recycling. All these factors creat difficulty in pre-setting final charging voltage. Further, since the charging voltage is pre-set, the cell voltage will increase; when the frequency of recycling intensifies, the cell capacity will be decreased.

(5). Temperatur control method: Connect a thermostat with the cell, when the cell temperature reaches a high level, it will turn off the charging input; when the temperature decreases, the charging input is turned on.

A thermistor may be connected in the same manner.

Either lvay, it is very difficult to reach the 100% capacity due to the factors, such as its sensitivity, area of connecting surface, internal resistance rate within the cell, environmental temperature difference, and the charge rate.

(6). Other specific charging methods: This method is designed for specific situations such as dump-time charge, rate of voltage charge, and so on. All these specific charging methods either require complicated equipment, large area, and expenses, or apply only to some specific conditions. Therefore, it is not suitable for commercial purpose.

In general, all the known conventional charging methods have but one purpose, i.e., to "put enough energy into battery and expect maximum output when battery is being used1,. However, none of the above mentioned methods can meet this purpose efficiently, some of them even have negative results.

The prior patents and papers being aware of and deemed pertaining to the present invention are briefly described as follows: (1). U.S. Pat. No. 4,746,854 of Baker et al is a "Battery Charge System", which comprises a microprocessor to discontinue application of a high charge current when the battery voltage drops below a peak value by a value greater than a threshoLd value corresponding to stored digital data. The microprocessor is also used to obtain a discharge mode of operation and an autocycle mode of operation in which a charge operation is performed after a discharge operation, the microprocessor being responsive to actuation of keys of a keyboard.In performing various operations, the microprocessor is used in performing analog-todigital conversious and it is additionally used in computing energy capacity and efficiency; however, the aforesaid invention is deemed not shown the features as improved in the present invention, which are-described in the claims thereof.

(2). U.S. Patent No. 4,742,290 of Sutphin et al is a "Recharging Battery Charger" which is a microprocessor controlled battery charger to charge a battery when the charging current is reduced to zero even though the charger is still connected to the battery. The microprocessor includes a means to read the voltage of the battery and also includes a timer. The voltage of the battery is periodically read and when it decreases below a predetermined value the microprocessor again establishes recharging of the battery first at an intermediate rate until either a maximum voltage is reached or a minimum dV/dt is reached and then the current is reduced to a lower current rate for a finishing charge of the battery for a given period of time. The aforesaid U.S.

Patent No. 4,742,290 provides less safety and efficient charge features to a battery than that of the present invention; in other words, the present invention has all the features of Patent No. 4,742,290, has, but said Patent does not show all the unique features as the present invention does; for instance, the Patent No. 4,742,290 can only charge two different batteries, while the present invention can charge more than two batteries.

(3). U.S. Patent No. 4,736,150 provides a methocl of increasing the useful life of rechargeable lithium batteries. The general object of the method is only to increase the useful life of rechargeable lithium batteries, i.e. to prolong the cycle life of a rechargeable lithium battery.

(4). U.S. Patent No. 4,755,733 of Laliberte provides a battery charging and cycling device, which is used for conditioning battery cells of different types. Said patent is an improvement of U.S. Pat. No. 4,342,954 (Griffith).

(5). U.S. Patent No. 4,763,061 (Schwarz) provides a primary switched-mode DC-DC converter with hummed input current and input voltage responsive control, which is mainly an improvement of circuit arrangement of this type known from "Applikationsbuch Band 2" (Application Manual, Valume 2), second edition, issued by Texas Instruments Deutschland GmbH, 1978, pages 132 to 135 so as to reduce the power loss in a switching power supply of the type.

(6). U.S. Patent No. 4,760,322 (Crampton) is a combination of power-supply/battery back-up power supply/battery charger, which mainly comprises an AC to DC power supply and a DC to DC power supply and a DC battery charging circuit within a single device so as to provide continuous DC power to a load regardless of the presence or absence of the AC power source. It is deemed that said patent has little pertineuce to the present invention.

(7). U.S. Patent No. 4,727,306 (Misak et al) is a portable battery charger, which mainly includes a thermister for sensing the battery temperature. The charger produces both a slowcharge current and a fast-charge current. .Upon detecting the presence of the battery, the unique charger turns on a fast-charge current produced by a switchable current source. The fast-charge current is subsequently turned off when the battery is fully charged as indicated by the status of monitered temperature and voltage conditions. Comparators are ultilized to monitor these voltage and temperature conditions.

According to a novel feature of the present invention, the monitored temperature thresholds are changed in response to the supply voltage. In fact, the aforesaid invention can merely monitor the voltage and temperature condition of a battery being charged without providing the features as claimed in the claims of the present invention.

(8). U.S. Patent No. 4,767,977 (Fasen et al) relates to a battery charger, which mainly comprises a fast charge line connected to the battery for providing a constant high charging current, a trickle charge line connected to the battery for providing a constant low charging current thereto simultaneously with the high charging current, a current regulating means and a slope detecting means. The aforesaid invention is simply a general battery charger without having the multi-functions as mentioned in the present invention.

(9). U.S. Patent No. 4,774,449 (Elkins) is a transformerless battery charger in combination with a battery, and method of charging a battery.

The aforesaid transformerless battery charger is deemed a general charger being incomparable with the present invention in terms of features and functions.

(10). U.S. Patent No. 4,755,735 (Inakagata) is a charge control circuit for a battery charger; the invention can provide a means for ensuring a consistent charge control over varying ambient temperature conditions.

After scanning the above identified prior patents, it is apparent that none of them shows the features of the present invention, and provides a complete charging functions to a cell or a battery pack; in other words, the present invention has become a backstop for all the drawbacks of the aforesaid disclosures.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the charging current respoiise of a typical sealed Ni-Cd battery pack upon being charged at constant voltages ranging from 23.0 volts to 11.6 volts.

Figure 2 illustrates the charging current response of the same battery pack as described in figure 1 upon being charged at constant voltages ranging from 9.6 volts to 11.6 volts.

Figure 3 illustrates the charging current response of the same battery pack as described in figure 1 upon being charged at constant voltages ranging from 9.6 volts to 10.4 volts.

Figure 4 illustrates the battery voltage and charging current responses of a typical battery pack upon being charged by means of the periodic intermittent charge.

Figure 5 shows the battery voltage change, period and control code of the same battery pack as described in figure 4 recorded by a printer upon being charged by using the periodic intermittent charging method.

Figure 6 shows the characteristics of charge according to this invention under the condition of continuously charging two cells by two different channels, in which: Figure 6a shows the input voltage curve.

Figure 6b shows the charging output controlling curve of channel 1.

Figure 6c shows the cell voltage reaction curve of channel 1.

Figure 6d shows the charging current reaction curve of channel 1.

Figure 6e shows the charging output controlling curve of channel 2.

Figure 6f shows the cell voltage reaction curve of channel 2.

Figure 6g shows the charging current reaction curve of channel 2.

Figure 7 shows a disassembled view of the embodiment of the main control unit in accordance with the present invention.

Figure 8 shows the bottom view of top lid of main control unit of the present invention.

Figure 9 is a sectional view along line IV - IV in figure 8.

Figure 10 is a sectional view along line V - V in figure 8.

Figure 11 shows the top view of the main control unit.

Figure 12 is a sectional view along line VII - VII in figure 11.

Figure 13 is a sectional view along line VIII - VIII in figure 11.

Figure 14 is a sectional view along IX - IX in figure 11.

Figure 15 shows a disassembled view of the embodiment of the switching power supply unit in accordance with the present invention.

Figure 16 shows the top view of switching power supply unit of the present invention.

Figure 17 is a sectional view along line XII - XII in figure 16.

Figure 18 is a schematic diagram of the switching power supply unit.

Figure 19 is a functional block diagram of the circuits shown in figure 18.

Figure 20 is a schematic diagram of the circuits of the main control unit.

Figure 21 is a functional block diagram of the circuits shown in figure 20.

Figure 22 is a flow chart illustrating the general operation of the main control unit and Figures 22 - 32 show graphically the test results tabulated below in Addendum 1 and Addendum 2.

OBJECT OF THE INVENTION *************************** Instead of using the conventional charging process, the inventor has developed a new charging process which has the following features: 1. With a constant current circuit, the battery can be charged at a high charge rate so as to shorten the charging time.

2. A central processing unit (CPU) is used to control the constant current circuit to charge n battery with periodic intermittent charge; therefore, the condition of battery can be controlled to avoid high pressure and high temperature so as to reach the highest charging efficiency.

3. The battery voltage during each period of periodic intermittent charge can be sensed with an analog-to-digital converter (A/D converter), and the result sesnsed is transmitted into CPU for deciding whether the voltage is increased or decreased, so as to have the battery being fully charged.

4. To charge several batteries simultaneously with several constant current circuits respectively controlled by CPU alternatly.

5. During charging, the voltage of each battery is detected with multiplexer and A/D converter, and the results detected are fed back to the CPU so as to have each battery charged with adequate charge input according to their different remained capacity and characteristics.

6. When the CPU has found battery reaching fully-charged condition, it will control the constant current circuit to shut off charging current to avoid overcharging.

7. After the charging process being completed, the CPU sends out a signal at intervals to the constant current circuit so as to keep the battery in fully-charged condition.

8. According to the present invention, the battery can be charged to a desired condition, i.e., to put enough energy into the battery and the battery can provide maximum output upon being used.

DESCRIPTION OF THE PREFERRED EMBODIMENT This charging device of the present inventions is further described as follows: 1. Charging theory: The present invention is designed according to the theory of operation and characteristics of the cell. The present invention can have the cell charged in the shortest time without damaging the cell or jeopardizing the serviceable life thereof. This invention supplies a smooth and steady D.C. voltage with constant current, and utilizes a high charge rate to shorten the charging time. Further, the present invention can detect the variation of cell voltage during charging process, and uses the method of comparing voltage to know whether the cell voltage is increased or decreased so as to show whether the cell is fully-charged or not.

Due to the fact that time required for charging depends upon charge rate - C value, and that the level of cell voltage and the rate of rise also depend upon charge rate, the charge rate can directly affect the temperature, the internal pressure, life, and capacity of cell. Therefore, it is very important to determine the charge rate, C value, especially the upper level of the charge rate.

Figure 1, 2 and 3 illustrate how to determine the C value according to the present invention.

Figure 1 shows a typical battery pack for test charging; the battery pack consists of six cells of 1.2 Volts, having a standard capacity of 1,200 mAh, and the battery pack can provide a 7.2V 1200mAh after being connected in series. In the process of testing, with constant charging voltage ranging from 8.0 volts to 11.6 volts, it is tested every 0.4 volts to watch the response of charging current while charging. As shown in figure 1, during the starting stage, the charging current has little change; whenever the charging voltage increases over about 10.0 voltage, the charging current starts to increase noticeably and rapidly.

This reaction indicates that, during charging process, the internal pressure and cell temperature will rise slightly if the cell is charged with a small charging current; in other words1 the heat has enough time to dissipate, and the charge input can be accepted effectively, but it takes longer time. Otherwise, the internal pressure and cell temperature will rise rapidly if the cell is charged with a large charging current, and therefore, the quality of the cell will be affected, and most of the charge input would be consumed by heat loss; although it takes shorter time, but the charging efficiency is low.

Needless to say that when charging current excess the tolerable limitation of a cell, on one hand, the heat can not be totally dissipated; on the other hand, the safety vent is continuously in open state to release the Oxygen gas; both will cause the cell to have a damage and to shorten the life thereof.

Figure 2 shows the same test for the same battery pack with 0.4 volts interval, but the scope of charging voltage has been decreased from 9.6 volts to 11.6 volts; also, the monitor time has extended from 5 seconds to 20 seconds. The curve clearly shows that when the charging voltage excesses about 10.0 volts, the charging current increases rapidly.

In order to illustrate the change of charging current further more clearly, the charging voltage is to be tested at 0.1 volt interval ranging from 9.9 volts to 10.4 volts.

One noticeable point to be mentioned here is that when such battery pack being tested with at interval of 0.1 volt, which is equivalent to 1/60 volts of each single cell, it indicates that the charging voltage increases only slightly. Also, the charging voltage ranging from 9.9 volts to 10.4 volts falls under 0.1 volt to individule single cell. Figure 3 illustrates the curve of the charging current response; when the charging voltage is below 10.2 volts, the change of the charging current is very slight, but when it exceeds 10.2 volts, the charging current starts to change drastically. Therefore, it is apparent that the charging voltage should not exceed 10.2 volts, and the sorresponding charging current should be under 4 amperes. Therefore, a battery pack with a standard capacity of 1,200 mAh may be obtained by setting the charge rate under 10/3 C.In order to avoid high pressure and high temperature to damage the cell as discussed before, the maximum charge rate should be set under 10/3 C.

As for the selection of minimum charge rate, the main factor involved is the time. As discussed previously, all the charge rate under the maximum charge rate may be used for charging the battery. In order to shorten the charging time a higher charge rate should be used.

The second factor involved is the environmental temperature, especially when charging is conducted in lower temperature surroundings. One situation is the increase of internal resistance when the temperature is low.

For instance, a fully-charged cell has an internal o resistance about 0.07 ohm at -18 C, and about 0.035 o ohm at 25 C. Also, the completely discharged cells have an impedance approximately 10 times higher than the fully-charged cells. Another situation is that the descrease of the density of electrolyte would cause the freezing point to rise during charging process; therefore, it should be conducted with higher charge rate to overcome the impedance, and the heat created from charging would offset the effect caused by the rise of freezing point.

Another consideration is the storage characteristics of cell. High charge rate would recover the activity of the active materials when a cell being storaged for a long time.

With all the factors discussed above, the inventor has finally selected 1C as the minimum charge rate for the testing battery pack.

After the maximum and minimum charge rates having been selected, the inventor has found that the most appropriate charge rate of rC is between lC and 10/3 C, wherein r is an element of positive real number: 1C < rC < 10/3 C, wherein r e IR ... (a) One important point needs to be mentioned here is that the cells with different sizes and types and specifications would require different ranges of rC. However, the maximum and minimum charge rates may be determined according to what have indicated above. The main factor affects the range of rC is the amount of electrolyte. Another factor is the difference of the internal resistance which varies according to the sizes of cell.

This invention is based on the rC range discussed and a higher charge rate. For instance, a cell of 1,200 mAh standard capacity may be charged with a smooth and steady voltage of direct current at a charge rate of 3C.

The charging process is conducted with periodic intermittent method (to be discussed in detail later). In the mean time, the change of cell voltage to be sensed through A/D converter during each period, and the results sensed is to send back to CPU to decide whether cell has reached its full capacity or need to be charged further.

Figure 4 and the data listed in figure 5 illustrate how CPU detects the battery voltage of a 7.2V-1,200mAh battery pack and the procedure thereof. The A/D converter reads battery voltage, and then the CPU compares the former and latter voltages to see if there is any increase or decrease.

The brown curve of figure 4 shows the charging current curve and battery voltage curve when charge is started; and periodic number is 68 (please note that the periodic number 68 represents the first charging period, as this invention uses the method of hexadecimal down count for the period number, as shown in figure 5); it indicates that the battery voltage is at a low level, while the charging current is high, i.e., at the highest output. When the charge input excess 50% of the cell capacity, as shown by periodic number 30 with blue curve, the battery voltage has increased and the charging current has decreased.

When battery capacity is reaching full level, as shown by periodic number 29 with green curve, its voltage has already reached the highest point, and the charging current would reach the lowest point.

If the charging process continues, the battery voltage starts to drop, while the charging current starts to climb, as shown by periodic number 21 with red curve, i.e., the battery reaching the full capacity and being overcharged.

The CPU compares the voltages in every charging periods with that of the previous periods.

If the voltage is still going up, the charging process continues; if the voltage is going downwards, it means that the battery has reached its full capacity, the charging process should be stop. Flalçe sure that the voltage is continuously going down, being not afected by other causes; this charging process will continue, and compare several times before making the final decision.

This is done by a method of count-down confirmation. During the comparison, if the voltage starts to increase, the count-down confirmation may be stopped, and the previous charging procedure may be repeated; during the comparison, the results show the voltage continuing to decrease, after count-down confirmation, CPU will send a signal to the constant current circuit to shut off the charging current because the battery has been fully charged. This process also suits the purpose of charging different size or type of battery. Further, this process controls charging effectively, and can avoid overcharging.

2. Charging method: As discussed before, the rC represents theoretically a high charge rate range. If the charge rate within the range is adopted, and the cell is charged continuously, the internal pressure and cell temperature would increase rapidly, and it can not be maintained for a long time; otherwise, it would accumulate gas and heat which would cause high pressure and high temperature. And this is the reason why the conventional charger tries to avoid using such high charge rate. This is also the biggest challenge to conventional charging method.

The first question, when charging a battery within rC range, would be how to control the cell not to generate heat nor gas to cause negatived effect, and how to obtain the highest charge efficiency.

This invention uses periodic intermittent charge along with rC rate through CPU to control the constant current circuit for fast-charging cell/battery pack; it not only effectively controls the pressure and the temperature upon the cell/battery pack reaching full capacity, but also alternately controls several constant current circuits to charge several cells/battery packs simultaneously.

The periodic intermittent charge is a systemical charging and stopping method. Every charging time plus the stopping time is formed into a period.

Figure 6 shows the controlling method, while figure 6a shows the input voltage supplied by the switching power supply; and figures 6b, 6c, 6d show the charging output controlling curve, the cell voltage reaction curve, and the charging current reaction curve of first channel (channel 1) respectively; figures 6e, 6f, 6g show the charging output controlling curve, the cell voltage reacticn curve, and the charging current reaction curve of second channel (channel 2) respectively.

It needs to explain why there are channel 1 and channel 2. This invention is designed for charging two or more than two cells/ battery packs. The CPU has four individual channels which control four different contstant current circuits to charge four different cells/ battery packs simultaneously. Therefore, to shut down the channel being used would be able to charge 3, 2 or 1 cell/battery pack; naturally, it can be expanded to a desirable number by adding CPU and associated components. To use two channels is simply for the purpose of explaining the special features of the method.

Figures 6b and 6c show the charging output controlling curve, when the CPU starts to operate; it sends out a Hi signal to both channel 1 and channel 2 constant current circuits; after a period of time, it sends out a Lo signal to channel 1 and channel 2 constant current circuits in order to send a current to charge the cell/battery pack upon the constant current circuit receiving the Lo signal.Since the whole process is under the full control of CPU, its internal software, and the charging output control of channel 1 and 2, so figure 6b is used to illustrate the output controlling process of charnnel 1 as follows: In the early charging stage, a charging method called quick-pulse charge is used to make a preliminary charge to a cell with a fixed time T the charging time of every pulse is set at t lc and the stopping time is set at t ;; the period ls of pulse is set at t 1 t = t + t ..... (b) 1 lc ls T = n X t ..... (c), wherein n e N 1 1 1 1 (i.e., n is an element of natural number) Next, when the normal charging process starts, cell is charged for time T by periodic 2 intermittent charge.Every charging time set at t , stopping time set at t , period set at t Zc 2s 2 and it is longer than previous mentioned t1: t = t + t (d) 2 2c 2s T = n X t ..... (e), wherein n E N 2 2 2 2 t > t (f) 2 1 During this normal charging procedure, the A/D converter senses cell voltage within the charging time t of each period, and sends the 2c results sensed to CPU for decision; when the decision is proved the cell voltage being decreased continuously, CPU would send a Hi to the constant current circuit which would turn off the charging current. Therefore, T time varies depending upon 2 the remaining capacity of cell before charging; in other words, it varies depending upon the initial cell voltage Vi before charging.Thus T is 2 considered as function of Vi; futher, in formula (e), t is a constant, and n is a function of Vi: 2 2 n = f(Vi) (g) 2 After time T , If the cell has been 2 removed from the charging device, the charging process would end automatically. Suppose it is not being removed, the CPU would maintain its output of Hi to the constant current circuit to stop the charging process; after a pre-set long time T , CPU would send a Lo to the constant 3 current circuit to start another charging process.

This process would be similar to the previous one.

Make a fast preliminary charge to a cell for a fixed T time by quick-pulse charging method, 4 then, periodic intermittent charge for time T 5 At time T of quick-pulse charge, set the 4 charging time of every pulse t = t , the 4c lc stopping time t = t ; so, the period of pulse 4s ls t = t , but time T is shorter than time T , i.e.

4 1 4 1 n is less than n ; therefore, formula (b) and 4 1 (c) may be rewritten as follows: t + t = t = t = t + t ... (b)' lc Is 1 4 4c 4s T1 T4 - = n < n = - ... (c)', wherein n E N tl 1 4 t4 4 Also, at time T of periodic intermittent 5 charge, set the charging time of erery period t = t , the stopping time t = t ; so, the Sc 2c 5s 2s period t = t , but the number of period n is 5 2 5 considered as the function of the initial cell voltage Vi' while going through T time.

3 Therefore, n could be less than n . In other 5 2 words, it is possible that time T is shorter than 5 time T (it depends upon the length of time T , or 2 3 the cell's remaining capacity before T1 charging); so, we the formulas (d), (e), (f) and (g) may be re-arranged as below: t + t = t = t = t ... (d)' 2c 2s 2 5 Sc 5s T2 T5 - n # n = ................ (e)' t2 2 5 t5 t > t (f) 5 4 n = f(Vi, Vi') ... (g)', wherein n E N 5 5 During all the aforesaid procedures, the cell voltage is sensed within t charging time Sc span of each peroid. Once a continuing decrease of cell voltage is detected, charging current will be stopped which would end time T . If the cell 5 is removed the charging device; then, the whole.

process is completed. If the cell is not removed; then, a repeat of previous process would commence again from time T to T and T automatically.

3 4 5 All the above are the procedures of channel 1.

As for channel 2, figure 6e shows similarity to channel 1, i.e., quick-pulse charge for time T1, periodic intermittent charge for time T , and after time T repeat time T of quick-pulse 2 3 5 charge and time T cycle. Thus, satifies the 5 formulas (b)', (c)', (d)', (e)', (f)' and (g)'.

There is one difference from that of channel 1, i.e., when channel 1 charging output control is at Lo, channel 2 charging output control is at Hi, and vise versa. Therefore, what would happen is that when channel 1 is in charging condition, the channel 2 would be in idle condition; when channel 2 is in charging condition, the channel 1 would be in idle condition. So, each single cell, can be done through a periodic intermittent charge; for two cells, it is to be done through an alternating manner. In order to charge two different cells effectively, the charging time and the stopping time of every period of both quickpulse and periodic intermittent charge are set in equal condition.Thus, formulas (b)' and (d)' are re-arranged as follows: t = t = 1/2 t = 1/2 t = t = t ...(b)" lc ls 1 4 4c 4s t = t = 1/2 t = 1/2 t = t = t ...(d)" 2c 2s 2 5 Sc 5s In other words, CPU alternatly controls two channels charging two different cells at the same time effecitively.

As for the voltage and current reaction while charging. Channel 1 and channel 2 are very similar to each other as shown in figures 6c, 6d, 6f and 6g, except the channel 2 reaction time is shorter than channel 1 for a short span of controlling time, which is 1/2 time of a period, including the period of quick-pulse t , t and 1 4 the period of normal charging t , t . Therefore, 2 5 the reaction of channel 1 is illustrated.

Figure 6c shows the cell voltage reaction curve; at time T1, cell voltage increases during every charging time t along with the increase of lc period; under normal charging condition, the cell voltage increases during charging time t in the 2c beginning, and then starts to decrease upon cell approaching the fully-charged state. When the CPU detects the cell voltage being decreasing continuously, it will stop the charging current, and end time T charging. Then, through idling 2 time T , the cell voltage would decrease which was 3 carsed by self-discharge, and it would increase when T time charging starts; then, end time T 4 5 charging similar to time T , and repeating 2 automatically from time T over and over.

3 As we knew that charging should not be done over a long time within rC range during normal charging procedure; so, it is very important to select T and T . Figure 3 shows 2c Sc when the charging is at 10.2 volts of constant voltage, the charging current drops rapidly; then, it becomes steady after 4 seconds; when the charging time exceeds 10 seconds, the charging current starts to go up; it indicates that the cell is affected by heat, which is the result of the fast charging. Suppose we continue the charging process under this condition, it would accumalate heat to cause a high temperature and high pressure.Similarly, the same thing will happen when charging at 10.1 volts to 10.0 volts; conincidentally, this invention has 3C charge rate for the cell of 1,200mAh capacity, which falls between 10.0 and 10.1 volts; therefore, the charging time is set at t and t for 10 seconds 2c Sc under 3C rate.

Further, A/D converter senses the cell voltage within the charging time t and t of 2c Sc every period during periodic intermittent charge.

In order to sense actual voltage value and not a sharp varied value during starting to charge as shown in figure 4, it should be sensed two seconds after the charging started when voltage goes steady; therefore, this invention is set to sense it at the 7th second. Also, in order to sense two different cells through A/D converter, the multiplexer is used to do the automatic switching selection which would enable A/D conveter to sense the cells connected with channel 1 and channel 2 respectively and to repeat automatically.

As for charging current reaction as shown in figure 6d, during the early charging stage time T , the charging current maintains the maximum output, and also at the beginning of time T 2 While period count increases (that is the capacity increasing gradually), the charging current starts to drop when cell reaches its full capacity, it would drop to the lowest point and climb when voltage starts to decrease. It has been illustrated this above, and of course, the reaction of time T and T are similar to time T 4 5 1 and T 2 The above description is the charging method of this invention, which provides a method to charge cell within rC range, but not to cause high pressure and high temperature to damage the cell.The periodic intermittent charge can charge the cell to start its electro-chamical reaction, and then after a period of time, the oxigen is generated from the positive plate to pass to the negative plate through separator for consumption, and the heat is released from cell for cooling; then, charging and stopping are made periodically until cell reaching its full capacity.Thus, the charging efficiency would not be affected by heat, and maintained in a steady level during whole charging; if the present invention is compared with the conventional method, the present invention is deemed much superior with the reasons explained below: Suppose we charge a same cell at T + T 1 2 time for total T time: 1+2 First, at 3C charge rate with the method of this invention, i.e., to satisfy formulas (b), (c), (d), (e) and (f); meanwhile, set the charging time and the stopping time of every period equally, i.e., to satisfy formulas (b)" and (d); therefore, the total charge input C 1+2 C = 3C X 1( n X 1/2 t )+( n X 1/2 t )] 1+2 1 1 2 2 = 3C X 1/2 ( T + T ) ........... (h) 1 2 Simultaneously, set 3/2 C charge rate with the conventional method for charging cell continuously, then the total charge input C 1+2' C = 3/2 C X ( T + T ) .......... (i) 1+2' 1 2 Compare formulas (h) and (i) and find that C = C which means both total charge 1+2 1+2' inputs are equal, but the charging efficiency for cell is completely different from each other.

According to formula (i), when cell capacity approachs 60% of the standard capacity, high temperature and high pressure would occur.

Fomula (h) does not have this problem. Also, formula (h) can funtion on two or more different cells simultaneously with the alternate charging method, and it not only can save time, but also has multiple results.

Further, the quick-pulse charging method of this invention during early stage of charging can reinstate the activity of active materials on positive plate and negative plate when a cell being storaged for long time; but, for a normal cell, it not only can shorten the time required for charging, but also could charge cell under low ambient temperature.

Also, the alternate charging method is to use the CPU to alternately control two or several constant current circuits, and through A/D converter and multiplexer, to charge and sense two or more than two cells simultaneously.

When normal charging procedure is completed, if the cell is not removed, the CPU will repeat the process periodically to maintain the cell in full-charged condition.

In general, this invention shows an effective way of charging cell/battery pack, suits our ultimate goal of "put enough energy into battery and expect the maximum output when battery is being used".

3. Application: This invention can be used for all kinds of sealed Ni-Cdcells/battery packs. A charging device for charging battery pack has been selected as embodiment, which requires high level of technical standrad during operation.

The hardware structure of the embodiment according to the present invention is described as follows: Figure 7 and figure 15 illustrate the disassembled view of the present invention, showing merely the prime parts thereof but not all the parts thereof.

Figure 7 illustrates the structure of a main control unit, which mainly includes a control circuit board 2, a top lid 3, and a bottom board 4.

Figure 15 illustrates the structure of a switching power supply unit, which mainly includes a power supply board 5, a top lid 6, and a bottom board 7.

The control circuit board 2 and the power supply board 5 include a rectangular two circuit boards 21 and 5i respectively, and a plurality of electronic parts on the boards.

The shape and structure of the control circuit board 2, the top lid 3 and the bottom board 4 of the main control unit as shown in figure 7 are formed into a symmetrical shape respectively. In order to avoid duplicate description to the same parts or assemblies mounted at different locations, each reference numeral is added with a suffix letter "L" to indicate that the parts or assembly is located at the left side, or with a suffix letter "R" to indicate that a parts or assembly is located at the right side, while the suffix letter "M" indicates a parts or assembly being located in the middle portion of a board.The suffix letters may be omitted when a description is made with a drawing First, take the control circuit board 2 for instance; it includes three LED indicators 22L, 22M and 22R, being arranged along a line; each of the indicators is mounted on a LED socket 221L, or 221M or 221R, which is installed on the front part of the circuit board 21; two connector sockets 23 mounted on both sides of the board 21, and each connector has two conductive wires 231 and 232, being connected with the board 21; two U-shaped radiator fins 24 are mounted on both sides of the circuit board 21, with the opening sides facing outwards respectively.Both sides of the U-shaped. radiator fin 24 have two vertical groove 241 and 242 respectively; a plug-board 25 is fixedly soldered on the rear left side of the circuit board 21, i.e., behind the U-shaped radiator fin 24L; a U-shaped cut 211 is furnished on rear right side of the circuit board 21, i.e., behind the U-shaped radiator fin 24R; the rear side of the cut 211 has two slots 212 and 213.

The cut 211 is used for receiving the switch case 261 of a switch 26, and the two metal terminals 262 and 263 of the switch 26 are to be inserted into the two slots 212 and 213, being soldered to the circuit board 21 directly. Two round holes 214 are furnished on the rear end of the circuit board 21 for mounting two metal ends 271 of two binding posts 27 respectively to be soldered on the circuit board 21. The four corners of the circuit board 21 are provided with four round holes respectively 215 and 216.

The top lid 3 is made of plastic material, by means of injection molding; the top lid 3 is best described by referring to figures 7, 8, 9 and 10. As shown in figure 7, the outer shape of the top lid 3 looks like two trapezoidal blocks being piled up each other. As shown in figure 9, the two trapezoidal blocks are connected together with a hollow space inside thereof. The front middle part of the lid 3 has a wedge-like nose 31, being connected between the front top surface and the front slanting surface of the lid 3. On the front of the top surface, there are three round recesses 32L, 32M and 32R with three round holes 321L, 321M and 321R respectively.Near both sides of the wedge-like nose 31, there are two rectangular socket holes 33 respectwvely. The rear end of the top lid 3, there are three partition plates 34L, 34M and 34R, being vertically connected between the front top surface and the rear slanting surface. One binding post hole 35L is furnished between two partition plates 34L and 34M, while the other binding post hole 35R is furnished between another two partition plates 34M and 34R.

The shape of the binding post hole is corresponding to the shape of the plastic base 272 of the binding post 27 as shown in figure 8, i.e., two oblong holes. Both rear sides of the top lid have two reverse U-shaped cuts 36 as shown in figures 7, 8 and 9. The top lid 3 is furnished with several ribs 37 arranged in parallel and lateral manner; between two ribs 37, there are several rediating holes 371, being furnished in the bent partion between two ribs. In the four corners of the top lid 3, there are four hollow round posts 38 and 39 respectively. The lower end of each hollow round post has an extended partion 381 (or 391), which is to be inserted into the round hole 215 (or 216) on the circuit board. The rectangular socket hole 33 of the top lid has a reverse U-shaped groove 331 on the upper side thereof, and a tongue-shaped part 332 extended into the lower side of the socket hole 33.Both sides of the rectangular socket hole 33 have two L-shaped socket-supporting plates 333 and 334 respectively as shown in figure 8 arranged in opposite and symmetrical position, and each socket-supporting plate has an indented side 335 (or 336), being opposite to the other. Around the radiating holes 371, there are three dust shields 372, 373, and 374. The dust shields 372L and 372R are two rectangular shields arrranged in parallel and opposite position between the radiating holes 371L and the radiating holes 371R. The dust shields 373 and 374 are rectangular flat shields as shown in figure 10, being installed in front and rear of the radiating holes 371; therefore, the radiating holes are surrounded with the three dust shields.

The bottom board 4 as shown in figure 9, is made of plastic material, and it has a flanged edge, a double-cross-shaped rib 41, whereby the board 4 is divided into six blocks; each block is furnished with a plurality of vents, i.e., vents 42 in the front blocks, vents 43 in the middle blocks and vents 44 in the rear blocks. On the rear right side of the bottom board 4, there is a U-shaped cut 45, which forms a rectangular hole with the opposite reverse U-shaped cut 36 on the top lid 3 so as to receive the switch case 261 of switch 26. In the four corners of the bottom board 4, there are four short hollow posts 46 and 47 respectively; the center lines of the four short hollow posts 46 and 47 are to be in alignment with the center lines of the four hollow round posts 38 and 39 respectively.

Following the description of the control circuit board 2, the top lid 3 and the bottom board 4, the steps of assembling the aforesaid three unit are described along with the figure 7, 11, 12, 13 and 14 as follows: (1). To mount the two binding posts 27 on the top lid 3: The threaded partion 273 of the plastic base 272 of the binding post 27 is put into the binding post hole 35 in the rear of the top lid 3, and let the annular portion 274 of the binding post 27 rest against the top lid 3; then, mount a spring washer 275 and a hexagonal nut 276 on the threaded portion 273 of the binding post as shown in figure 11 and 12; the binding posts are used as D.C. (direct current) input terminals on the top lid 3.The partition plates 34 are mainly used to isolate the two binding posts 27L and 27R from each other to prevent the positive wire and the negative wire from being contasted together; further, the partition plates are also used for reinforcing the top lid to prevent the lid 3 from becoming deformed, and also for decorative purpose.

(2). To mount two connector sockets 23 on the top lid 3: The connector socket 23 is a rectangular casing as shown in figure 7; the top side of the socket has a wedge-shaped lug 233 located on the front edge thereof, and two rectangular lugs 234 and 235 located on both sides respectively; the left and right sides of the socket 23 are furnished with two V-shaped leaf springs 236 and 237 respectively as shown in figure 14; the outside of the tails of the leaf springs 236 and 237 are formed into a cascade shape. The midbottom side of the socket 23 has a T-shaped lug.

As shown in figures 11, 12 and 13, the connector socket 23 is to be inserted into the socket hole 33 from the inside of the top lid 3; the top side of the socket 23 is fitted against the top of the socket hole 33, while the bottom side of the socket 23 is fitted against the tongue-shaped part 332 under the rectangular socket hole 33 so as to retain the connector socket 23 in place firmly.

The wedge-shaped lug 233 of the socket 23 can easily pass through the reverse U-shaped groove 331 on the top of the socket hole 33 to let the connector socket 23 continue to move forwards, and as soon as the two leaf springs 236 and 237 pass through the indented sides 335 and 336 of the socket-supporting plates 333 and 334, the leaf springs 236 and 237 will spring outwards automatically to have the cascade-shape portion thereof retained at the indented sides 335 and 336 respectively without being. moved backwards, but being able to move forwards; the connector socket 23 is moved forwards continuously until the rectangular lugs 234 and 235 being retained inside the top lid 3 and the T-shaped lug 238 being retained by the tongue-shaped part 332 in the socket hole 33 without being moved forwards; in that case, the connector socket 23 will be unable to move forwards and backwards.

Since the V-shaped leaf springs 236 and 237 are engaged with the socket-supporting plates 333 and 334 respectively, and the rectangular lugs 234 and 235 are retained inside the top side of the rectangular hole 33, the connector socket 23 would not be moved laterally. The front end of the connector socket extends out of the top lid 3 so as to facilitate a plug to connect with it as an output terminal.

(3). To install the control circuit board 2 under the top lid 3: The dust shields 373 and 374 inside the top lid 3 should be inserted into the grooves 241 and 242 of the U-shaped radiator fin 24 exactly and respectively as shown in figure 12; then, let the extended portions 381 and 391 of the four hollow round posts 38 and 39 of the top lid 3 fit into the four round holes 215 and 216 on the corners of the circuit board 21 respectively, and then let the three LED indicators 22 fit through the three round holes 321 on the front end of the top lid 3; almost simultaneously, the two metal ends 271 of the two binding posts 27 on the rear end of the top lid 3 as mentioned in step (1) are put through the two round holes 214 on the circuit board 21, and are extended under the bottom side of the circuit board 21; then, the metal ends 271 are directly soldered to the circuit board 21.

The switch 26 is fitted through the reverse U-shaped cut 36R on the rear right side of the top lid 3, and mounted in place by means of two V-shaped leaf springes 264 on both sides of the switch 26 to be retained on both sides of the reverse U-shaped cut 36R; at the same time, the metal terminals 262 and 263 are inserted into the slots 212 and 213 on the circuit board 21, and then they are soldered to the circuit board 21 directly; the assembling work between the control circuit board 2 and the top lid 3 is done.

(4). To assemble the bottom board 4 and the top lid 3: As shown in figures 7, 12 and 13, the bottom board 4 is assembled together with the top lid 3 by means of four round head screws 48 and 49 to be fitted through four fish-eye holes 461 and 471 of the four short hollow posts 46 and 47 respectively, and then the screws are fitted into four hollow round posts 38 and 39 respectively; simultaneously, the control circuit board 2 is sandwiched between the top lid 3 and the bottom board 4 by means of the four short hollow posts 46 and 47 of the bottom board 4 and the hollow round posts 38 and 39. The U-shaped cut 45 on the rear right side of the bottom board 4 and the reverse U-shaped cut 36R are formed into a rectangular hole for receiving and fixing the switch 26.On the rear left side of the circuit board 21, there is a plug-board 25 as shown in figure 12, which is exactly located in the reverse U-shaped cut 36L on the rear left side of the top lid 3; the reverse U-shaped cut 36L and the edge of the bottom board 4 are formed into a rectangular hole. When the plug-board 25 is not in use, the rectangular hole may be covered with a rubber cap 361L as shown in figure 7.

By following the aforesaid steps, the control circuit board 2, the top lid 3, and the bottom board 4 are assembled into one piece.

The structure of the whole device has the advantages of being strong, easy to assemble and reliability; for instance, the connector socket 23 is directly retained in the rectangular socket hole 33 without using additional rectaining parts.

The binding post 27 is directly fixed in place by soldering the metal end 271 thereof to the circuit board 21. The partition plates 34 are used for preventing the positive and negative wires from being wrongfully contacted. The dust shields 372, 373 and 374 as shown in figures 12 and 14 and the radiator fins 24 are mounted around the radiating holes 371 to prevent dust or other matters or metal stuffs from falling onto the circuit board 21.

Furthermore, the switching power supply unit is described as follows by referring to figure 15: The power supply board 5 includes a pair of D.C. output wires 52 being connected to the central front of the circuit board 51. The wires 52 are mounted with a conical wire clamp 53, of which the rear end has an annular groove 531.

A LED indicator 54 is mounted in a LED socket 541 being fixedly mounted in the front left part of the circuit board 51. On rear left side of the circuit board 51, there is a U-shaped cut 511 with two slots 512 and 513; the U-shaped cut 511 is used for fitting the switch socket 551, while the two slots are to receive the two metal terminals 552 and 553 of the switch 55. A pair of A.C.

input wires 56 are connected to the rear left part of the circuit board 51, and the two wires are mounted with a conical wire clamp 57 that has an annular groove 571. The four corners of the circuit board 51 are furnished with four round holes 514 and 515 respectively.

The top lid 6 of the switching power supply unit is designed in accordance with the outer shape of the top lid 3 of the main control unit, and it is made of plastic material by injection molding into a cascaded trapezoid shape.

The central front edge of the top lid 6 is provided with a semi-circular cut 61. On the top of the top lid 6, there is a parallelogram-shaped niche 62 as shown in figure 17. The bottom of the parallelogram-shaped niche 62 is furnished with a round recess 63 with a round hole 631 therein.

The rear left side of the top lid 6 has a reverse U-shaped cut 64. The top lid 6 also has several parallel ribs 65 laterally around the top and both sides thereof. There are several radiating holes 651L and 651R being provided between two ribs at the bent portion of the ribs. The rear right side of the top lid 6 has a semi-circular cut 61, as shown in figure 17. The four corners inside the top lid 6 are furnished with four hollow round posts 66 and 67 respectively, being similar to those posts 38 and 39 in the top lid 3. The four hollow round posts 66 and 67 have four extended portions respectively on the lower ends thereof to be fitted in the round holes 514 and 515 at the four corners of the circuit board 51.

The bottom board 7 is similar to the bottom board 4 in shape and structure except having a semi-circular cut 71 on the front central edge, and a semi-circular cut 72 on the rear left edge thereof; therefore, no further description is given.

Further, the power supply board 5, the top lid 6 and the bottom board 7 are assembled together by referring to figures 15, 16 and 17 in accordance with the steps described as follows: (1). To assemble the power supply board 5 and the top lid 6 together: According to figure 12, the wire clamps 53 and 57 should be fitted into the semi-circular cuts 61 and 68 in the front side and the rear side of the top lid 6 respectively by means of the annular grooves 531 and 571 thereof. The extended portions of the four hollow round posts 66 and 67 of the top lid 6 are fitted into the round holes 514 and 515 on the four corners of circuit board 51 respectively; at the same time, the LED indicator 54 will also be fitted through the round hole 631 of the top lid 6.The switch 55 is then inserted into a reverse U-shaped cut 64 on the rear left side of the top lid; the V-shaped leaf springs 554 on both sides of the switch 55 are retained by both sides of the reverse U-shaped cut; simultaneously, the two metal terminals 552 and 553 are inserted into the slots 512 and 513 respectively, being soldered to the circuit board 51.

(2). To assemble the bottom board 7 and the top lid 6 together: Referring to figures 15, 16 and 17, the bottom board 7 is attached to the top lid 6 by means of four screws 73 and 74 to pass through the fish-eye holes 751 and 761 of the four short round posts 75 and 76 respectively before being fixedly attached to the four hollow round posts 66 and 67 of the top lid 6. At the same time, the power supply board 5 will be sandwiched tightly in place.

The U-shaped cut 77 on the rear left side of the bottom board 7 and the reverse U-shaped cut 64 of the top lid 6 are assembled together to form into a rectanglar hole for receiving the switch 55.

By means of the aforesaid steps, the power supply board 5, the top lid 6 and the bottom board 7 can easily be assembled together.

After the hardwafre structure of the present invention being described, the control circuit of the present invention is described as follows: First, the circuit of the switching power supply unit along with the circuit diagram of figure 18 and the block diagram of figuare 19 are described in the follow paragraphs.

Figure 19 shows the circuit of switching power supply unit, which mainly includes: an EMI filter 581 which mainly includes a capacitor C001 and an inductor L001 as shown in figure 18; a rectifier/filter 582 which mainly includes a bridge rectifier D001 and a capacitor C002; an input voltage sensing circuit 583 which mainly includes two resistors ROll and R012; a PWM controller 584 which mainly includes an integrated circuit ICOOl; a switching transistor 585 which includes a transistor Q001 as shown in figure 18; an output transformer 586 which includes a transformer T001 as shown in figure 18; a pair of rectifier diodes 587 which includes diodes D006 as shown in figure 18; a direct current filter circuit 588 which mainly includes an inductor L002, and three capacitors C009, C011 and C013; an output voltage detecting/adjusting circuit 589 which mainly includes an integrated circuit IC002, a zener diode DO04,a capacitor COld2, five resistors R016, R017, R018, R019 and R20; an OPTO coupler 590 which mainly includes an integrated circuit IC003 and a capacitor C014.

According to the above structure, the switching power supply unit can receive an input of any A.C. voltage ranging from 90 to 265 volts, at a frequency ranging from 47 Hz to 63 Hz. The operating theory thereof is described with the following steps: (1). The alternating current (A.C.) which comes through A/C input wire 56 first goes through the EMI filter 581 to block out any outside interference and the disturance which may occur during the switching power supply unit operating.

(2). Then, it will go through the rectifier/filter 582 to change into direct current of steady voltage, and to supply to PWM controller 584.

(3). Turn on the switch 55, which is the switch SW001 as shown in figure 18; after the PWM controller 584 receiving enough voltage, it creats a vibrating output along with the on and off of the switching transistor 585 to divide the direct current of high voltage into an alternating current.

(4). 'llle aforesaid alternating current will go through the output transformer 586. After the output of secondary winding of transformer 586 receiving the voltage of alternating current, it will send this alternating current to the rectifier diodes 587 to go through the direct current filter circuit 588 to provide a very steady and smooth direct current, and to light up LED indicator 54 to tell the operator that there is voltage output.

(5). However, after step (1) through step (4), the output voltage of direct current might not be the voltage that we expected. Thus, the output voltage should be adjusted by the variable resistor R017 of the output voltage detecting/adjusting circuit 589 until obtaining the voltage we expected.

(6). If there is any change occured at the output end, i.e., any charge of the loading which is connected with D/C output wire 52, an output voltage detecting/adjusting circuit 589 has to be used to detect its change, and the OPTO coupler 590 and PWM controller 584 are to be use to adjust the wave width to acquire the steady output voltage.

(7). If there is any change on the input voltage of alternating current, the feed back coil of output transforme 586 and the PWM controller 584 have to be used the wave width so as to keep the output voltage steady.

After the above procedures, a steady and smooth voltage of direct current can be obtained to supply the main control unit via the D/C output wire 52. This D.C. voltage is also used for charging the battery pack.

The circuit of main control unit along with the circuit diagram of figure 20 and the block diagram of figure 21 are described as follows.

Figure 21 shows the circuit of main control unit, including the previous mentioned three LED indicators 22 (LED indicator 22L is the diode D101 as shown in figure 20 which is the indicator of channel 1, LED indicator 22R is the diode D102 as shown in figure 20 which is the indicator of channel 2, LED indicator 22M is the multi-color diode D106 as shown in figure 20 which is the power indicator, using two different colors to distinguish channel 1 and channel 2); two connector socket 23 (connector socket 23L is the connector CON2 as shown in figure 20 which is the output terminal of channel 1 to connect the first battery pack 281; connector socket 23R is the connector CON3 which is the output terminal of channel 2 to connect the second battery pack 282); a plug-board 25 is the connector CON 1 as shown in figure 20; a switch 26 is the switch SW100 as shown in figure 20; two binding post 27 (binding post 27L is the positive terminal of input, while 27R is the negative terminal). The other parts mainly includes: a +5 volts regulator 283 which mainly includes a regulator RG1 and a capacitor C101 as shown in figure 20; 'a capacitor 284 which is the capacitor C104 as shown in figure 20, and used for power on and off auto-reset; a buzzer 285 which is the oscillator X101 as shown in figure 20; a time base oscillator 286 which mainly includes a crystal oscillator X102 and two capacitors C102 and C103 as shown in figure 20; channel 1 constant current circuit 287 which mainly includes two integrated circuits IC102A and IC102B, a transistor Q101, a power transistor Q105 (attached to the cooling fin 24L) and resistor R120; channel 2 constant current circuit 288 which mainly includes two integrated circuits IC102C and IC102D, a transistor Q102, a power transistor Q106 (attached to the cooling fin 24R) and a resistor R121; a multiplexer 289 which mainly includes an integrated circuit IC103 and four resistors R114, R115, R118 and R119, an analon-to-digital converter (A/D converter) 290 which mainly includes two ingetrated circuits IC104A and IC104B, a capacitor C105 and five resistors R106, R107, R108, R109 and R122; channel 1 short/ polarity detector 291 which mainly includes a transistor Q107, a diode D107 and three resistors R127, R128 and R132; channel 2 short/polarity detector 292 which mainly includes a transistor Q108, a diode D108 and three resistors R129, R130 and it131; a central processing unit (CPU) 293 which is the integrated circuit IC101 as shown in figure 20; CPU 293 is the process center of the main control unit.

The operating theory of main control unit is described as follows: (1). Turn on the main control unit, and connect the current for chargiing of battery by connecting the above mentioned D/C output wire 52 of switching power supply unit to the binding post 27. It is necessary to mention here that this switching power supply unit is designed for using indoor alternating current power; when there is no such A.C. power available, a regular 12 volts in automobile battery may be used to replace the switching power supply unit because that the main control unit can receive an input of direct current between 12 volts and 14 volts.

(2). Connect the first battery pack 281 to connector socket 23L, and the second battery pack 282 to connector socket 23R; then, turn on switch 26; all three LED indicators 22 will be lighted up to indicate that current is applied and the charging is in progress.

(3). The 12 - 14 volts input direct current goes through the +5 volts regulator 283, and then a steady 5 volts direct current is applied to all the integrated circuits of channel 1 constant current circuit 287, channel 2 constant current circuit 288, multiplexer 289, A/D converter 290 and CPU 293. In the mean time, the same 12 - 14 volts direct current will also be applied to the channel 1 constant current circuit 287 and channel 2 constant current circuit 288 directly so as to be ready for receiving signal from CPU 293 to start the charging process.

(4). When CPU 293 receives the 5 volts direct current, it will charge the capacitor 284 for one or two seconds before the CPU 293 starting to function. This will enable the software in CPU 293 to start fresh every time, and the speed will be controlled by the time base oscillator 286.

(5). When CPU 293 starts to funtion, it will send Hi to channel 1 and channel 2 constant current circulits 287 and 288 at the same time.

After few milli-seconds, it will send Lo to channel 1 constant current circuit 287 only. The integrated circuit IC1Q2A receives Lo and passes through IC102B to send out a signal to transistor Q101. Thus, 12 - 14 volts direct current goes through transistor Q101, and power transistor Q105 starts to charge the first battery pack 281.

(6). After channel 1 constant current circuilt 287 charging battery pack 281 for 1/2 time t , CPU 293 will send Hi to channel 1 constant current circuilt 287 to stop the charging process. In the mean time, CPU 293 will send Lo to channel 2 constant current circuit 288 with the same process previously mentioned in step 5 to charge the second battery pack 282 for same 1/2 time t (7). CPU 293 will repeat its Hi and Lo process within a pre-set time T to channel 1 and channel 2 constant current circulits 287 and 288 alternatly to charge both battery packs 281 and 282 with the quick-pulse charge method for t period.

(8). At the end of time T , CPU 293 will again send Lo to channel 1 constant current circuit 287. This Lo is to maintain the 1/2 time t, in other words, it charges the first battery 2 pack 281 at 1/2 time t . Meanwhile, CPU 293 will 2 send signal to the multiplexer 289 within this 1/2 time t to open the gate of channel 1 to let 2 analogue signal enter the A/D converter 290 for reading the voltage value of the first battery pack 281 to change the signal into digital data before sending it back to CPU 293.

(9). After channel 1 constant current circuilt 287 completing 1/2 time t charging, CPU 2 293 will send Hi to constant current circuilt 287 to stop charging the battery pack 281. In the mean time, CPU 293 will send Lo to channel 2 constant current circuilt 288 to charge the second battery pack 282 for the same 1/2 time t 2 It will also send signal to multiplexer 289 in the same manner as to channel 1 to read the voltage value of the second battery pack 282, and change it into digital data before sending it back to CPU 293.

(10). CPU 293 will repeat the previous procedures (8) and (9) alternatly by sending Hi and Lo to channel 1 and channel 2 constant current circuilts 287 and 288 to charge battery packs 281 and 282 with periodic intermittent charge in period t . During the same process, CPU 293 would 2 send a signal to multiplexer 289 automatically to switch and select within the charging time t of 2c each period, and also controls A/D converter 290 continuously to read the voltage value of battery packs 281 and 282, and then turns the value into digital data to feed back to CPU 293.

(11). After CPU 293 receives the datas from A/D converter 290 and stores in random access memory (RAM), CPU 293 will compare the former and latter period battery voltage so as to determine increase or decrease of voltage and to decide whether the charging should carry on or not.

(12). When CPU 293 has sensed the voltage of one battery pack, for example the first battery pack 281, is decreasing, it would start the count-down confirmation process to re-compare the voltage of this battery pack 281 to confirm the continuity. At the end of the count-down confirmation, if CPU 293 has confirmed the voltage being decreased, it would send a Hi to the channel 1 constant current circuit 287 to stop charging the battery pack 281. In the mean time, it would turn off LED indicator 22L, and energize the buzzer 285. At the end of count-down confirmation, if CPU finds the decrease of voltage is not continued, it would resume its normal charging process until next count-down confirmation occurs.

(13). In the previous step (12), when CPU 293 stops to charge the battery pack 281, it would still control the channel 2 constant current circuit. 288 to charge second battery pack 282.

After CPU 293 repeat step (12) on battery pack 282, it would turn off LED indicator 22R and buzzer 285.

(14). Accouding the the previous two steps (12) and (13), we know that, regardless which battery pack is fully charged, the buzzer 285 would sound for attention. And the LED indicator 22L or 22R would indicate which battery pack is ready to be removed. The LED indicator 22M would be still on with solid color, and LED indicator 22L or 22R would tell the operator which battery pack is still being charged.

(15). When both battery packs 281 and 282 are fully charged but not removed yet, after a pre-set time T , CPU 293 would repeat steps from 3 (5) to (7) to charge these non-removed battery packs with quick-pulse charge method for period t 4 The determination of time T , for a non-removed 3 battery pack, would start at the moment when the charging stops; for two battery packs 281 and 282, since neither were removed, it would start at the moment when the last battery pack being fully charged, and the charging process stopped.

(16). At the end of time T , CPU 293 4 would continuously repeat steps from (8) to (14) to charge the two battery packs 281 and 282 with periodic intermittent charge for t period until 5 reaching full capacity. If battery packs were not removed, CPU would repeat step (15) and step (16).

The above steps from (1) to (16) is the operating theory for charging normal battery.

However, if we encounter with some abnormal situations such as a damaged battery, wrong connection with charging device, battery being not connected with charging device, battery having a short circuit, the operating procedures would be as follows: (17). Channel 1 short/polarity detector 291 and channel 2 short/polarity 292 would detect, before and during the charging process, the condition of battery packs 281 and 282. Once defect being detected, for example the first battery pack 281, the channel 1 short/polarity detector 291 would send a signal to the integrated circuit IC102A of channel 1 constant current circuit 287; then, the integrated circuit IC102 will not send a signal to the integrated circuit IC102B to control transistor Q101 and power transistor Q105 to interrupt the flow of 12 - 14 volts direct current; in other words, it will not charge battery pack 281.

Since the channel 2 short/polarity detector 292 does not discover any defect of battery pack 282, the charging process will be continued for time T with quick-pulse charge.

(18). After time T , CPU 293 is trying to read the voltage of battery pack 281 through multiplexer 289 ad A/D converter 290, to see if the voltage of the battery pack 281 is beyond the pre-set voltage range. (For a single sealed Ni-Cd cell, the pre-set voltage range is between 0.9 volts and 2.0 volts.) If so, LED indicator 22L would blink, and the buzzer 285 will sound for attention about the abnormal condition of battery pack 281.

(19). When CPU 293 starts to charge with periodic intermittent charge at t and t period, 2 5 it also starts a count-down confirmation during the charging period. It will set a maximum n or 2 n period counts, referring to as n . This n 5 max max is set according to the previous formula (g) based on the assumption that battery capacity before charging is zero (i.e. Vi = 0); it is also set according to the charge rate, which is selected within the rC range based on battery standard capacity. Then, the n is determined by using max the total time T required for periodic max intermittent charge devided by the period.

During the charging process and after n count, if CPU 293 has not determined the max continuity of voltage decrease of one or both battery pack, it would stop the charging current through constant current circuit 287 or 288.

It will also blink LED indicator 22L or 22R, and sound buzzer 285. This not only will warn the abnormal condition of battery pack, but also will protect the battery pack.

(20). The buzzer 285 will stop automatically after a given period of time when battery packs 281 and 282 are fully charged.

If one or neither battery pack is removed from the main control unit, CPU 293 will periodically (at time t interval) signal buzzer 285 to sound 3 within time T to indicate that the battery pack(s) 3 is(are) still being charged.

(21). There is an extra-function assembly. The seven-bit LED indicator 294, and a printer 295 or interface with pulg-board 25 are included in the assembly so as to show with the seven-bit LED indicator 294 about the changes during charging process (i.e. the changes during each period within time T and T ) or print the 2 5 changes with printer 295 as shown in figure 5.

The operating theory of main control unit has been described from step (1) to step (21).

The entire function of CPU 293 for charging process is illustrated with the flow diagram in figure 22. The CPU 293 is consisted of hardware and software; the hardware mainly a microrocessor, including a read-only memory (ROM), a random access memory (RAM), and an input/output (I/O); the function of the software is shown by the flow diagram of figure 22, and is described with the following steps: (1). When CPU 293 receives current (power on) or starts to reset (turning on switch 26), it will start its initial function to set all the parameters such as: time, charging method, etc.

(2). Then it will start preliminary charging procedure, i.e. quick-pulse charge.

(3). After step (2), it will start normal charging, L.e. periodic intermittent charge First, it will perform 50% duty cycle charging (since it will charging two battery packs 281 and 282 equally; the charging time of each period t = 1/2 t , i.e. 50% duty cycle). The charging 2c 2 current is a pre-set value within rC range.

(4). In the mean time, it will detect the voltage of the battery packs and change into digital data through A/D converter 293.

(5). The result will be sent to sevenbit LED indicator 294 to display.

(6). After receiving the digital data, CPU 293 will be able to determine battery pack being in normal or defect condition. If there is any defect, such as wrong connection, open circuit, short circuit, it can be detected by voltage. This will cause the buzzer 285 to sound, LED indicator(s) 22L and/or 22R to blink; the charging current will also be cut off to be shown by seven-bit LED indicator 294 with " BADx (wherein x = 1 or 2; when x = 1 it means that the first battery pack 281 is defective, when x = 2 it means that the second battery pack 282 is defective).

(7). During the previous step (6), if there is no such defective condition, CPU 293 will continue its charging process until being fully charged. Afte battery pack 281 or 282 being fully charged, it will signal buzzer 285 to sound for attention, will turn off LED indicator 22L or 22R, and stop charging current.

(8). During the previous step (7), if CPU 293 detects battery pack 281 or 282 being not yet fully charged, it will determine whether charging time exceed T ,i.e., if the number of max period n or n exceeds n . If it does exceed 2 5 max T time, this is the indication of abnormal max condition of battery; then, it will proceed according to the procedures what we have mentioned previously regarding defective battery.

(9). During the previous step (8), if CPU 293 determines that charging time does not exceed time T , it will detect whether both max battery packs 281 and 282 are processed. If the answer is negative, it will repeat the process according to step (3) to the next battery pack.

(10). During the previous step (9), if CPU 293 determines both battery packs 281 and 282 are processed, it will send the voltage data of two battery packs 281 and 282 to printer 295 for printing.

(11). Then, CPU 293 will go back to normal charging procedure, and monitor whether both battery packs 281 and 282 have been charged.

If CPU 293 concludes that none of both battery packs 281 and 282 has been charged, it will repeat the procedure of step (3) for the first battery pack 281.

(12). During the previous step (11), if CPU determines both battery packs 281 and 282 have been charged, it will decide whether both battery packs 281 and 282 are removed. If two battery packs 281 and 282 are removed, it will control the seven-bit LED indicator 294 to show " AOFF ", the buzzer 285 to sound, and turn off all LED indicators 22. The charging process is completed.

(13). During the previous step (12), if the two battery packs 281 and 282 are not removed, CPU 293 will determines whether it exceeds time t . If the answer is negative, it will repeat 3 step (12) for final judgement.

(14). If it does exceed time t , it will 3 signal buzzer 285 for attention. It will also determine whether it exceeds time T , if it does 3 not exceed time T , it will repeat the previous 3 step (12), and sound buzzer 285 every time t 3 interval until all battery packs 281 and 282 being removed or pass time T 3 (15). During the previous step (14), if it does exceed time T , CPU 293 will start a re 3 initial procedure.

(16). Then, it will repeat a quick-pulse charge for time T preliminary charging.

4 (17). Next, it will repeat the charging procedure through step (3) automatically.

The above step (1) to step (17) illustrate the entire function of CPU 293. The CPU 293 can operate the same way to charge four battery packs at the same time by adding two LED indicators, two constant current circuits, two connector sockets in the controlling circuit; naturally, it is necessary to change "channel 2" into "channel 4", "2 channels" into "4 channels", and "2 batteries" into "4 batteries" on the flow diagram of figure 22. This would even show the unique features of this invention.

In order to further illustrated this invention, two test reports are described as follows: Addendum 1 is a test report of a typical .2V-1,200mAh battery pack during charging and discharging process, wherein Addendum la shows the testing data and the reaction curve of the battery voltage and charging current during charging.

Addendum Ib shows the testing data and the reaction curve of the battery temperature and ambient temperature during charging.

Addendum lc shows the testing data and the reaction curve of the battery temperature and ambient temperature during discharging.

Addendum 1d shows the testing data of the discharging time, discharging current and battery voltage, and the reaction curve of the battery voltage vs.

discharging time.

Addendum 2 is a test report of the life and endurance of another typical 7.2V-1200mAh battery pack, wherein Addendum 2a shows a life test of 401 cycles and the percentage of actual capacity of each cycle over standard capacity, and the reaction curve of such percentage vs. number of cycle.

Addendum 2b shows the testing data of the discharging time, discharging current and battery voltage, and the reaction curve of battery voltage vs.

discharging time. It is based on random selection of the first, 101st, 201st, 301st and 401st cycle of addendum 2a.

The addendum 1 shows how this invention controlling battery temperature and internal pressure during entire charging process as shown in addendum lb; the battery temperature is very close to the ambient temperature, and it only increase slightly at the the end of charging process. This also means the internal pressure of battery maintaining at a very low level with a slight increase at the final stage.

As for the time of charging, it is shown at addendum la that, after 132 periods of periodic intermittent charge, the battery pack will be fully charged. These 132 periods include 8 periods for confirmed comparison which is necessary for confirming the continuity of voltage decrease.

Since the charging time t and stopping time t 2c 2s of each period is 10 seconds, so we can use formulas (d) and (e) to calculate the actual time T as follows: 2 T = 132 X ( 10 + 10 ) = 2,640 seconds 2 Also, T has been set as 480 seconds; therefore, the time required for entire charging process is 3,120 seconds which is about 52 minutes.

As for charging efficiency and actual capacity as shown in addendum ld, we, after 52 minutes of charging, discharge the battery pack with 6 ohms constant loading and stop discharging when battery voltage is reduced below 5.86 volts; the results shows that the actual capacity is tested as 1,572mAh, which is 372mAh higher than standard capacity.

The life and endurance of battery is clearly shown by addendum 2 that after 401 charging and discharging cycles, the actual capacity is still at 1,442.4mAh (the test is interrupted at the 44th cycle due to current interruption). One point must be noted that this test is done in a destructive manner. Since the inventor uses high discharge rate during discharging process, it is done under such a strict condition; therefore, the actual endurance should be better than the result of the test report shows.

SUMMARY OF THE INVENTION As we have illustrated above, this invention not only achieves the eight objectives, but alE;o has the following unique features; 1. Testing feature: The charging device can test the battery condition with short/polarity detector to determine whether the battery is being charged or not; the multiplexer, A/D converter and the CPU are used to detect the defects of battety, and to signal LED indicators and buzzer to warn the operator.

2. Safty and reliability features: This invention has safty design; for instance, when the abnormal condition of the battery is detected by the short/polarity detector, it will control the constant current circuit to stop the charging current; the set of n during periodic intermittent charge provides max the battery a protection to prevent from overcharging; with the proper use of charge rate within the tolerable limitation of battery along with periodic intermittent charging method, the battery temperature and internal pressure can be maintained at a low level during charging.

All these not only can avoid any possible human error, but also avoid any unnecessary damage to the battery.

3. Flexibility feature: This invention has a switching power supply unit, which can receive any input voltage of alternating current within the.range from 90 volts to 265 volts without extra adjustment. It will not be affected by any surge voltage during charging. Also, we can use a regular 12 volts automobile battery to replace the switching power supply unit for outdoor operation.

Further, during quick-pulse charge, the slight temperature increase would allow battery being charged as under low temperature surrounding; during normal charging, the controlling of battery temperature allows battery being harged under high temperature surrounding.

This feature makes it very flexible for application for indoor to outdoor operation, from cold weather area to extreme hot weather area.

4. High economical efficiency feature: This invention enables the input energy to be used effectively and completely.

For a single battery, the periodic intermittent charging method makes the input energy being absorbed by controlling battery temperature, it not only maintains the chgarging efficiency at a steady level during whole charging process, but also avoids the unnecessary waste of energy.

For two or more than two batteries, the alternate charging method allows the input energy economically employed by several batteries to avoid unnecessary waste of time, and this can obtain several times of efficiency higher than charging a single battery by the conventional charging device.

5. Convenient and practical feature: This invention is compact,- ligh-weight, and reliable. It has a very wide use in commercial and industrial fields, and even for military purpose. It not only has a very simple operating requirement, but can also be recorded and detected during the entire process with LED indicator, printer, and computer.

6. Testing and detecting feature: This invention can be functioned as testing and detecting device. The actual time required for testing the life and endurance of battery is very lengthy. Sometimes the testing and experiment process may require years. This invention along with some extra softwares and hardwares is deemed a very effective and a practical testing device for the battery life and endurance.

In conclusion: This invention is designed according to the theory of operation and the characteristics of sealed Ni-Cd cell. The derivation of rC range, the quick-pulse charging method, the periodic intermittent charging method, and the alternate charging method have been described. In view of the above description, it is believed that this invention is in condition for allowance, and such a Notices is respectfully solicited.

Claims (46)

1. A fast charging device for sealed nickel-cadmium cylindrical rechargeable cell/battery pack comprising: A theory of charging whereby a battery being charged with a constant voltage can be tested so as to determine a minimum charging time but a maximum charging current under a given bearable limit of a battery in accordance with the response of charging current to said battery and to obtain the maxinum charging efficiency; and in accordance with the factors of the characteristics of a battery to be charged, a short charging time required, affecting the charging at a low temperature, and the storage characteristics of a battery to determine a minimum charging current; and the best changing current value means the best changing rate (rC) within a range between the maximum value and the minimum value, and then a higher charging rate to be selected among said range for charging a battery with a constant current value; and the battery having a characteristic of voltage becoming lowered gradually after being charged to a given capacity, and according to said characteristic, a battery being tested continuously during charging so as to monitor the variation of the battery voltage by using a comparison method, whereby the battery capacity able to be known whether becoming saturate or not; method of charging, which is an alternate charging method to alternately charge several batteries by using an input power supply; and for a single cell, it is an intermittent charging method, and said method first provides a short time of preliminary charge, i.e., a quick-pulse charge, and then a periodic intermittent charge being used to perform normal charge; and the cell voltage being tested during each periodic charging period, and the cell voltages measured being compared, and whenever the cell voltage being reduced continuously, the normal charge is to be discontinued at once; and after a normal charge being made, one quick-pulse charge and one periodic intermittent charge have to be made again after a given period of time, which is an automatic cyclic charging method; a charging device, which includes a main control unit and a switching power supply unit, and said main control unit includes a control circuit board, a top lid and a bottom board, and said control circuit board being mounted with a plurality of parts including a voltage regulator for 5 volts, a power supply switch capacitor, a buzzer, a time base oscillator, two constant current circuits, a multiplexer, an analog-to-digital converter, two short/polarity detectors, and a central processing unit; and said switching power supply unit includes a power supply board, a top lid, and a bottom board, and said power supply board further including an EMI filter, an A.C. rectifier/filter circuit, an input voltage sensing circuit, a PWM controller circuit, a switching transistor, an output transformer, a pair of rectifier diodes, a direct current filter circuit, an output voltage detecting/adjusting circuit, and an OPTO coupler; and whenever an A.C.

(alternating current) passing through said switching power supply unit, said power supply unit provides a smooth D.C. voltage for said main control unit, from which a constant current is supplied to charge a battery, and said main control unit also detects and compares the voltage of said battery being charged so as to determine the voltage of said battery being increased or decreased.

2. A fast charging device for sealed nickel-cadmium cylindrical rechargeable cell/battery pack as claimed in claim 1, wherein the main feature of said theory of charging is that the maximum charging current can be determined by means of a charging test to a battery with a constant voltage charging; and first the charging voltage is set a higher range, and said charging voltage being increased gradually after a given period of time as a short time test; and in accordance with the variation of a charging current, it is indicated that whenever the charging voltage is exceeding a given voltage, said charging current is to be increased considerably; and then said charging voltage range is reduced and the test time is also increased, and said constant charging voltage is to be tested after a given interval; and whenever said charging voltage becoming exceeding said constant voltage, the charging current is to be increased evidently and in that case, the charging voltage should be reduced, and the interval to test the battery is also reduced so as to find a charging voltage exceeding a specific voltage value which can cause the charging current to vary considerably and said specific charging voltage is considered the maximum charging current.

3. A fast charging device for sealed nickel-cadmium cylindrical rechargeable cell/battery pack as claimed in claim 1, wherein the determination of the maximum charging current is done by using a 7.2 volts/1200mAh battery pack as a constant voltage charging test; and when said charging voltage is exceeding 10.2 volts, the charging current increases evidintly, and a charging current of 4 Amperes corresponding to said charging voltage 10.2 volts is deemed the maximum charging current, i.e., 10/3 C being the maximum charging rate.

4. A fast charging device for sealed nickel-cadmium cylindrical rechargeable cell/battery pack as claimed in claim 1 wherein the determination of the minimum charging current in said theory of charging is determined by using 1C as the minimum charging rate of the 7.2 volts/1200mAh.

5. According to any one of claims 1, or 3 or 4, wherein the best charging rate of said battery with a standard capacity of 1200mAh is within a range from 1C to 10/3 C as soon as the following formula s satisfied: 1C < rC < 10/3 C, and r E RI.

6. According to claim 1 or 5, wherein said best charging rate rC is a larger charging rate 3C to be used a charging rate within said rC range; and said constant current circuit can provide a steady D.C. voltage to furnish a fast charge to battery with a standard capacity of 1200mAh.

7. According to claim 1, wherein said analog-to-digital converter is used to test the voltage of a battery being charged periodically and mittently, and the test results are transmitted into a central processing unit for comparison so as to judge the ascending and descending condition of a battery voltage.

8. According to claim 1, wherein said central processing unit alternately controls several constant current circuits to charge several batteries in alternate manner.

9. According to claim 1, wherein said central processing unit is furnished with four separate channels for czntrolling said four constant current circuits respectively to charge four different batteries at the same time in an alternate manner.

10. According to claim 1, wherein said central processing unit can charge a given number of batteries by reducing the number of channels to be used in said central processing unit, or by increasing the number of said central processing unit and adding some hardwares.

11. According to any one of claims 1, 8, 9 or 10, wherein when said central processing unit has only two constant current circuits, said central processing unit can simultaneously have an output of high potential Hi output to be applied to the first channel and the second channel constant current circuits, and after a given period of time, said central processing unit can send out a low potential Lo to said first channel constant current circuit; and when said first channel constant current circuit receives said low potential Lo, said circuit generates a current. output to a battery connected therewith for charging; and then said central processing unit sends out a low potential Lo to said second channel constant current circuit, and simultaneously sends out a high potential Hi to said first channel constant current circuit; and when said second channel constant current circuit receiving said low potential Lo, said circuit supplying a current to a battery connected thereto; and when said first channel constant current circuit receiving said high potential Hi, said circuit discontinuing to supply output current to battery immediately, and repeating the aforesaid procedures to charge battery alternately.

12. According to claim 1, wherein said charging method can provide charging to a single cell by said central processing unit to send out a high potential Hi and a low potential Lo alternately to a constant current circuit, whereby said single cell being charged intermittently.

13. According to claim 1 or 12, wherein a quick-pulse charge for a period of time T1 is to be done in the beginning of said intermittent charge, and each of said quick-pulse charge time requires a fixed period of time tlc, a fixed period of time tls to stop charging, and a pulse period of tl to satisfy the following formulas: t1 = tlc + tls; T1 = nl x tl, wherein nl e N.

14. According to claim 12 or 13, wherein after said period T1 of quick-pulse charge, a normal charging procedure is to be followed, i.e., a period T2 of periodic intermittent charging, and each charging time is fixed for t2c and a stop charging time of t2, and let said periodic cycle be fixed as t2 and being larger than pulse period tl and also to satisfy the following three formulas: t2 = t2c + t2s; T2 = n2 x t2, wherein n2 E N; t2 > tl.

15. According to claim 14, wherein said periodic intermittent charging is to be done by testing the battery voltage with said analog-todigital converter during each periodic charging time t2c, and the testing results of the battery voltage being transmitted to said central processing unit to compare said voltages tested so as to know the voltage of the battery being in ascending or descending condition.

16. According to claim 7 or 15, wherein when ssid central processing unit surely senses the battery voltage being reduced, said central processing unit begins to charge the battery in a count-down and periodic intermittent manner, and simultaneously several comparison being made so as to surely prove the battey voltage being decreased continuously.

17. According to claim 16, wherein said count-clown confirmation is discontinued to restore the normal charging in case of the battery voltage becoming increased after several comparison of battery voltage.

18. According to claim 16, wherein if the battery voltage is surely proved to decrease continuously after several comparison being made, said central processing unit can send out a high potential Hi to said constant current circuit to cut off the charging current immediately to end the charging in time period T2.

19. According to claim 14 or 18, wherein the lengTh of time T2 is varied in accordance with the variation of voltage Vi of battery before being charged, and t2 being a fixed value, and the cycle number n7 being the function of Vi, and being described by: n2 = f(Vi).

20. According to claim 12 or 18, wherein said charging procedures are to be ended after said time period t2 and said battery charged being removed; and if said battery charged being not removed, said central processing unit continuing to transmit a high potential Hi to said constant current ircuit to stop the charging to said battery charged, and after a long time period T3, said central processing unit again automatically transmitting a low potential Lo to said constant current circuit to start another charging procedure.

21. According to claim 20, wherein said another charging procedure is to be done by charging a battery with quick-pulse charge for a period of time T4, which is similar to the quick-pulse charge in the time T1, and each charging time of said pulse being t4c = tlc, and the stop charging time being t4s = tls, and the pulse cycle thereof being t4 = tl; and the cycle number n4 being less than nl so as to satisfy the following two formulas: tlc + tls = tl = t4 = t4c + t4s; T1/tl = nl > n4 = T4/t4, in which n4 E N.

22. According to claim 20 or 21, wherein after said time period T4 quick-pulse charge, a time periodic T5 periodic intermittent charge is to be started, being similar to said periodic intermittent charge in time period T2; and each charging time period t'c = t2c, and the stop charging time t5s = t2, and the period t5 = t2 being larger than the pulse period t4; and the cycle number n5 being the function of voltage Vi' after time period T3, and being also the function of voltage Vi before the charging time period T1, and also satisfying the following four formulas: t2c + t2s = t2 = t5 = t5c + t5s; T2/t2 = n2 > , n5 = T5/t5, wherein n5 e N; t5 > t4; n5 = f(Vi,Vi').

23. According to claim 22, wherein during the period of periodic intermittent charge, said analog-to-digital converter is used to test the voltage of battery charged during each period of charging time t5c, and the test result being transmitted into said central processing unit for comparison and judgement of the battery voltage being increased or decreased, and if the battery voltage being decreased, a count-down confirmation being started to confirm the voltage being decreased continuously; and as soon as said central processing unit having confirmed said voltage being reduced continuously, and said unit instructing said constant current circuit to cut off the charging current after said count-down confirmation being ended so ss to end the charge in time period T5.

24. Accouding to any one of claims 20, 21, 22 or 23, wherein, if the battery charged is not removed from the charging unit, a repeating procedure is started from time period T3 through T4 (quick-pulse charge) to time period T5 (a periodic intermittent charge) i.e., an automatic cyclic charging method.

25. According to any one of claims 11,13, 14, 21 or 22, wherein in order to alternately charge two batteries with equal efficiency, the charging time ard the stop charging time in each period of the quick-pulse charge and in the periodic intermittent charge are equal to each other, and also satisfying the following two formulas: tlc = tis = 1/2tl = 1/2t4 = t4c = t4s; t2c = t2s = 1/2t2 = 1/2t5 = t5c = t5s.

26. According to any one of claims 6, 14 or 22, wherein when a battery having a standard capacity of 1200mAh is charged at a charge rate 3C, each period of charging time t2c and t5c under periodic intermittent charge is set at ten seconds.

27. According to any one of claims 7, 15, 23 or 26, wherein said analog-to-digital converter tests the battery voltage within ten seconds during the time periods t2c and t5c; and testing work is to be done at the 7th seconds after starting to charge.

28. According to any one of claims 7, 11, 15 or 23, wherein when said analog-to-digital converter tests the voltage of two batteries, a multiplexer is used as an automatic selective switch to faciLitate said analog-to-digital converter to conduct repeated tests to the batteries connected with said first channel constant current circuit and said second channel constant current circuit respectively.

29. A charging device according to claim 1, wherein the parts mounted on said control circuit board and being also related to said top lid and said bottom board in said main control unit of said device include: three LED indicators being arranged into a line at a regular space one another, and each said LED indicator being mounted in a cylindrical LED socket at a given height above and in the front of said control circuit board; two connector sockets, each of them being connected with two wires to said circuit board; and said connector socket being made of plastic material and formed into a rectangular shape, and the front edge of said connector socket having a wedge-shaped lug, and two rectangular lugs being furnished on both mid sides of said connector socket, and two V-shape1 leaf springs being furnished on both sides of said connector socket respectively, and the tail of each said leaf spring being formed into a cascade shape, and the mid bottom side said connector socket having > T-shaped lug; two U-shaped radiator fins being fixed on both sides of said circuit board, and the openings of said U-shaped radiator fins all facing outwards, and bota sides of the opening of each said U-shaped radiator fihaving a vertical groove; a plug-board being fixedly soldered on the rear right side of said circuit board;.

a switch fitted in a switch case, which is mounted in a U-shaped cut on the rear left side of said circuit board, and said U-shaped cut having two slots to receive two metal terminals of said switch, and then said two metal terminals being soldered to said circuit board; two binding posts being mounted into two round holes on the rear part of said circuit board respectively and being soldered to said circuit board via the metal ends thereof respectively.

30. A charging device according to claim 1, wherein said top lid of said main control unit is made of plastic material, being formed into a symmetrical shape by means of injection molding, and being similar to two trapezoidal blocks piled up with said smaller one on top of said larger one; and the front part of said top lid being furnished with a wedge-like nose, and the front edge part of said top lid being furnished with three round recesses being arranged into a line laterally, and each of said round recesses having a round hole; and two rectangular socket holes being provided on said top lid groove being furnished on the top side of said rectangular socket hole; and a tongue-shaped part extended into the bottom side of rectangular socket hole; and both inner sides of said rectangular socket hole being furnished with two opposite L-shaped socket-supporting plates respectively, and two opposite indented sides being provided on the two opposite sides of said two L-shaped socket-supporting plates respectively; three partition plates being vertically furnished on the rear side of said top lid; two binding post holes being furnished between every two said partition plates respectively; two reverse U-shaped cuts being provided on both rear sides of said top lid; several parallel ribs being laterally furnished on said top lid and extended downwards to both sides thereof, and between the bent part of every two said ribs, several radiating holes being furnished; and three dust shields being furnished inside said top lid and around said radiating holes; and four hollow round posts being provided at the four corners of said top lid, and the bottom end of each said hollow round post having an extended portion to be fitted through one of the four round holes at the four corners of said control circuit board.

31. A charging device according to claim 1, wherein the bottom board of said main control unit is mad of plastic material, being formed into a rectangular shape with flanges on the four sides thereof by means of injection molding; and the bottom surface of said bottom board having a double cross-haped rib to partition said board into six blocks, of which each has several vents; and the rear left side of said board having a U-shaped cut being opposite to said reverse U-shaped cut on said top lid so as to form into a rectangular hole to receive said switch case of said switch; and four short hollow posts being furnished at the four corners of said bottom board respectively, and the center holes of said four short hollow posts being aligned with the centers of said four hollow round posts of said top lid respectively.

32. A main control unit according to any one of claims 29, 30 or 31, wherein main control unit includes a control circuit board, a top lid and a bottom board, which are assembled together in accordance with the following steps: (1), to fix said two binding posts on said top board, and first puting the threaded portion of said binding posts through the binding post holes respectively to let the annular portion rest against said top lid, and then use a spring washer and a hexagonal nut to mount on said threaded portion to fix said biuding post in place;; (2), to fixedly mount said two connector sockets to said top lid by inserting said connector sockets into said rectangular socket holes respectively from the inside of said top lid, and the top of said connector socket being fitted against the top side of said socket hole, while the bottom of said connector socket being placed on said tongue-shaped part without being moved up and down; and let the wedge-shaped lug on the top of said connector socket pass through said reverse U-shaped groove on the top side of said socket hole, and said connector socket continuously moving forwards until the two V-shaped leaf springs on both sides of said connector socket passing through the indented sides of said L-shaped socket-supporting plates to let the cascade-shaped parts engage with said indented sides respectively and to cause said connector socket to be unable to move backwards, and until the two rectangular lugs on both sides of the top of said connector socket, and the T-shaped lug on the bottom surface thereof being engaged against the tongueshaped part under said connector socket without moving forwards anymore.

(3), to mount said control circuit board on said tp lid by inserting said dust shields into the groove in said U-shaped radiator fins correctly and respectively, and let the extended portions of said four hollow round posts on said top lid insert into the four round holes on said control circuit board respectively, and simultaneously let said three LED indicators pass through the three round holes in the front of said top lid, and the metal ends of said two binding posts being inserted through two round holes in the rear of said circuit board and being directly soldered to said circuit board respectively; and said switch being fitted into a reverse U-shaped cut on the rear left side of said top lid until the two V-shaped leaf springs on both sides of said switch case being retained by both sides of said reverse U-shaped cut, and simultaneously the two metal ends of said switch being inserted into the slots respectively on the rear left side of said circuit: board and soldered to said circuit board directly (4), to fit said bottom board to said top lid by using four round head screws to insert through the four fish-eye holes respectively of the four short hollow posts on said bottom board, and to screw into the four hollow round posts in said top lid; End simultaneously said control circuit board being tightly sendwiched between said top lid and said bottom board by said hollow posts thereof.

33. A charging device according to claim 1, wherein the power supply board of said switching power supply unit includes the following parts which are also related to said top lid and said bottom board: a pair of D.C. output wires being connected to th front mid part of said power supply board, and ssid pair of wires being mounted with a conical wire clamp which has an annular groove; a LED indicator being inserted into a LED socket that is fixed to the front left side of said circuit board; a switch being fitted into a U-shaped cut on the rear left side of said circuit board with the two metal terminals of said switch being engaged into two slots respectively;; a pair of A.C. input wires being connected to the rear left side of said power supply board, and said pair of wires being mounted with a conical wire clamp which has an annular groove.

34. A charging device according to claim 1, wherein the top lid of said switching power supply unit is made of plastic material, being formed into two tapezaidal blocks one above the other by means of injection molding; a semi-circular cut being provided at the front mid edge of said top lid; a parallelogram-shaped niche being furnished on the front left part of said top lid, and the bottom of said niche having a round recess with a round hole; a reverse U-shaped cut being provided at the rar left edge of said top lid; several ribs being provided laterally around the top and both sides of said top lid, and several radiating holes being furnished between every two said ribs at the bent part thereof; a semi-circular cut being furnished at the rear left side of said top lid; and four vertical hollow round posts being furnished at the four corners in said top lid respectively, and the lower end of each said hollow round post having a small extended portion.

35. A charging device according to claim 1, wherein the bottom board of said switching power supply unit has the same shape and structure as that of said main control unit except said semi-circular cuts on the front and rear sides of said bottom board.

36. According to any one of claims 33, 34 or 35, wherein the power supply board, the top lid and the bottom board of said switching power supply unit are assembled together in accordance with the following steps: (1), to fit said power supply board in said top lid by first mounting said conical wire clamps of said D.C. output wires and said A.C. input wires in said semi-circular cuts in the front and rear edges of said top lid respectively, and inserting the extended portions of said four hollow round posts of said top lid into the four round holes at the four corners of said circuit board; and inserting said LED indicator through the round hole on said top lid; and then said switch being fitted in said reverse U-shaped cut at the rear left edge of said top lid, and the V-shaped leaf springs on both ides of said switch being set against both sides of said reverse U-shaped cut respectively, and then the two metal terminals of said switch being inserted into the slots on the rear left side of said circuit board and being directly soldered thereto; (2), to mount said bottom board under said top lid by inserting four round head screws into the four fish-eye holes of said four short round posts of said bottom board, and then fixing said four round head screws into the four short round posts of said top lid respectively, and at the same time said power supply board being sandwiched in place by means ot said round posts of said top lid and said bottom board.

37. A charging device according to claim 1, wherein said switching power supply unit includes the following parts: an EMI filter mainly comprising a capacitor, and an nductor; a rectifier and filter circuit mainly comprising a Wheatstone Bridge rectifier and a capacitor; an input voltage sensing circuit mainly comprising two resistors; a PWM controller mainly comprising an IC; a D.C. filter circuit mainly comprising an inductor and three capacitors; an output voltage detecting/adjusting circuit mainly comprising an IC, a zener diode, a capacitor and five resistors; and an OPTO coupler mainly comprising an IC and a capacitor.

38. According to any one of claims 1, 33 or 37, wherein said switching power supply unit is able to receive any voltage ranging from 90 volts to 265 volts A.C., 47 Hz to 63 Hz, and the operation theory thereof being described as follows: (1), after A.C. power entering via said input wires, and first passing said ElI filter first; (2), then passing through said A.C.

rectifier/filter circuit to convert into a smooth D.C. to supply said PWM controller; (3), said switch being turned on to energize said PWM controller to generate an oscillation output and also to control a switch transistor so as to convert a high voltage D.C.

into A.C.; (4), said A.C. passing said output transformer, and the secondary winding of said output transformer transmitting said output A.C.

voltage to a rectifier diode and through said D.C.

filter circuit to obtain a smooth D.C. voltage and to light up a LED indicator to indicate a voltage output being ready; (5), said D.C. voltage obtained through the aforesaid steps (1) to (4) being not a D.C. value desired, and said D.C. voltage being adjusted by a variable resistor in said output voltage detecting/ adjusting circuit to become a voltage desired; (6), if a load connected to said D.C.

output wires having been varied, said varied load can be detected by means of said output voltage detecting/adjusting circuit, and also by using said OPTO coupler to couple said varied load to said PWM controller to adjust the width of wave so as to obtain a stable output; (7), if the input A.C. voltage being varied, the output voltage can be maintained in stable condition by means of the feed back coil of said output transformer to feed said variation into said PWM controller to conrol the width of wave.

39. A charging device according to claim 1, wherein said main control unit includes: a +5V. regulator comprising mainly a voltage regulator and a capacitor; a time base oscillator mainly comprising a quarty oscillator and two capacitors; two constant current circuits mainly comprising two ICs, a transistor, a power transistor, and a resistor; a multiplexer mainly comprising an IC and four resistors; an analog-to-digital converter mainly comprising two ICs, a capacitor, and five resistors; two short/polarity detectors mainly comprising a transistor, a diode, and three resistors; a central processing unit being an IC mainly comprising a hardware circuit and a software progarrl; and said hardware circuit mainly including a ROM, a RAM, and an input/output unit.

40. A charging device according to claim 29, wherein said control circuit board of said main control unit includes: three LED indicators, in which the left LED being the first clannel indicator, the right LED being the second channel indicator, and the mid LED indicating the ON or OFF of the power supply; and two colors being used for indicating said first and second channels in performing charging respectively; two connector sockets, in which the left connector socket being the output terminal of said first channel and being connected with the first battery pack, while the right connector socket being the output terminal of said second channel and being connected with the second battery pack; and two binding posts, in which said left binding post being the positive input terminal of D.C. power supply, while said right binding post being the negative input terminal of D.C. power supply.

41. A main control unit according to any one of claims 1, 25, 29, 38, 39 or 40, of which the operation theory are described as follows: (1), to connect said output wire of D.C.

power supply of said switching power supply unit to said binding post; and said switching power supply unit can also be replaced with a 12V. battery of automobile since said main control unit can use any input power supply of 12-14 volts D.C.; (2), to connect said first and second battery packs to said connector sockets respectively, and to turn on said switch, and then said three LED indicators being lighted up to indicate that said battery being charged; (3), a 12-14V.D.C. first passing through said +5V. regulator so as to obtain a stable +5 volts as a power supply for said constant current circuit, said multiplexer, said analog-to-digital converter, and said central processing unit; and said 12-14 volt D.C. power also directly supplying power to two constant current circuits, which are to charge said battery packs as soon as a signal from said central processing unit being given; (4), as soon as said central processing unit receiving said +5V. D.C. power, a capacitor for re-setting the power supply switch being charged first, and after about 1-2 seconds, said central processing unit starting to operate so as to let the software in said central processing unit start to execute, and the execution speed of said software being determined by said time base oscillator;; (5), when said central processing unit starting to operate, first it sending a high potential Hi to said two constant current circuits simultaneously; and after several milli-seconds, said central processing unit sending a low potential Lo to said first channel constant current circuit, and after the IC of said first channel constant current circuit being energized with said low potentail Lo, said circuit sending out a signal to a transistor so as to let said 12-14V.D.C. passing said transistor and a power transistor to charge said first battery pack; (6), after said first channel constant current circuit charging said first battery pack for 1/2 ti, said central processing unit immediately sending out a high potential Hi to said first channel constant current circuit to stop charging to said first battery pack, and simultaneously sending out a low potential to said second channel constant current circuit in the same manner as step (5) mentioned above to charge said second battery pack for 1/2 ti;; (7), within said time period ti, said central processing unit continuously and repeatedly sending out a high potential and a low potential to said first channel constant current circuit and said second hannel constant current circuit respectively to charge said two battery packs alternately with a quick-p-ilse charge on tl cycle basis;; (8), after said time period tl being over, said central processing unit again sending out a low potential to said first channel constant current circuit to charge said first battery pack for 1/2 t2, and simultaneously said central processing unit sending out a signal to said multiplexer to open the first channel gate so as to let said analog-todigital converter read the voltage on both terminals of said first battery pack and to convert the voltage into digital data to be transmitted to said central processing unit;; (9), after said first channel constant current circuit finishing 1/2 t2 charging, said central processing unit sending out a high potential Hi immediately to said first channel constant current circuit to stop charging to said first battery pack, and simultaneously said central processing unit also sending out a low potential Lo to said second channel constant current circuit to charge said second battery pack for 1/2 t2, and also sending out a signal to said multiplexer to turn on the second channel gate so as to let said analog-todigital converter read the voltage of said second battery pack, and to convert said voltage into digital data to be processed by said central processing unit;; (10), said central processing unit continuously repeating said steps (8) and (9), i.e., alternately sending out a high potential Hi and a low potential Lo to said two constant current circuits to charge said two battery packs alternately and intermittently on a time-period t2 basis; and at the same time, the voltage variation of said battery packs being read continuously by means of said multiplexer and said analog-to-dital converter and being transmitted into said central processing unit; (11), said central processing unit staring the data received from said analog-to-digital converter into a RAM so as to compare the voltage measured during a previous time period with the voltage measured during the next time period in order to know whether the voltage is increasing or decreasing;; (12), when said central processing unit detecting the voltage of one battery pack being decreased, said central processing unit starting a count-down confirmation immediately so as to confirm whether the voltage of said battery pack is decreasing continuousing, if after said count-down confirnation being over, the voltage of said battery pack being decreased continuously, said central processing unit immediately sending out a high potential Hi to said constant current circuit to stop cnarging, and to turn off the LED indicator of said channel and to let a buzzer send out a sound signal; and if detecting the voltage of said battery pack not decreasing continuously at the end of the count-down confirmation, the normal periodic intermittent charge being resumed immediately; (13), whenever said central processing unit detecting the voltage of one of said battery packs decreasing continuously and having stopped the charge to said battery pack; and said another battery pack still being charged under the control of said central processing unit until the voltage thereof being detected as decreasing continuously as in step (12) mentioned above, and then the charging thereto being stopped immediately, and the LED indicator of said chanel being turned off, and the buzzer thereof immediately sending out a sound signal; (14), as desiribed in steps (12) and (13) above, the sound signal of said buzzer and turning off said LED indicator showing which battery pack having fully been charged, and being removed from the connector socket, and the mid LED indicator being still in lighting-up condition to show only one color, and to show which battery pack being still charged;; (15), after said two battery packs being all fully charged, and one or two said battery packs not being removed from said main control unit within time period T3, said central processing unit repeating the steps (5) to (7) mentioned above again to charge said battery pack not being removed with a t4 quick-pulse charge for a period of time T4; (16), after said period of time T4 being over, said central processing unit repeating the steps (8) to (14) mentioned above to charge said battery pack with a t5 periodic intermittent charge; and if said battery pack still not being removed from said main control unit, said central processing unit continuously repeating the steps (15) to (16) mentioned above to charge said battery pack; (17), the short/polartiy detectors in said first and second channels detecting said first and second battery packs respectively when the charge being 3tarted or during the charging period whether there is any short circuit, or reverse polarity, or open wire, and if so, a signal being transmitted to the IC of the constant current circuit of said channel to control the transistor and power transistor thereof to block D.C. voltage of 12 to 14V. from flowing through and to prevent said battery pack from being charged;; (18), when said central processing unit detecting, by means of said multiplexer, any abnormal battery pack, such as to let said analogto-digital converter read the voltage thereof if it exceeding a pre-determined range, and if so, said central processing unit starting to drive the LED indicator of said channel to flash, and said buzzer to send out a sound signal; (19), when said central processing unit starting time-period t2 and t5 periodic intermittent charge, said unit also starting a count-down confirmation to said time period number by setting a maximum value n max of n2 or n5; and after battery pack being charged for n max periods, said central processing unit immediately cutting off the charging, lighting up said LED indicator and energizing the buzzer, although said central processing unit having not confirmed the voltage of said battery pack being decreased continuously; (20t, after a battery pack being fully charged and said buzzer having sent out a sound signal for a given period time, the sound signal being stopped automatically, and if said battery pack being not removed, said central processing unit would, within the time period T3, energie said buzzer to send out a sound signal every time period t3;; (21), said battery pack being connected, via a plug-board, with a seven-bit LED indicator, a printer or an interface card so as to show any variation of a battery pack being charged within time periods T2 and T5, and said variation being displayed with said seven-bit LED indicator or said printer.

42. A main control unit according to claim 41, wherein the pre-set value for a cell of 1,2 volts as mentioned in step (18) above of the operation theory thereof is set in a range from 0.9 volts to 2.0 volts.

43. A main control unit according to claim 41, wherin the n max of the cycle number as mentioned in step (19) of the operation theory of said main control unit is to be set on condition that the battery capacity is a zero value, and set according to the charge rate, which is selected within the said rC range based on battery standard capacity; then, said n max value is to be obtained by using the total time T max required for periodic intermittent charge devided by the period.

44. A main control unit according to any one of claims 39 or 41, wherein the control flow chart of the software program of said central processing unit is deseribed as follows: (1), whenever said central processing unit having received a signal to reset a power supply, a starting step is initiated first to set the parameters of time and charging method; (2), to start a preliminary charge for a time period T1, i.e., quick-pulse charge; (3), to start a normal charging by means of 50% periodic intermittent charge first with charging current to be set at a fixed value within said rC range; (4), to test the battery voltage in each charging period, and to convert said voltage tested into digital data bysmeans of said analog-to-digital converter;; (5), the digital voltage value being transmitted to said seven-bit LED indicator through said central processing unit to display the result; (6), after the digital voltage being obtained, it can be judged immediately whether the battery is out of order or abnormal; and if said battery being abnormal, said buzzer will be energized and said LED indicator will flash, and the charging circuit will be turned off, ad said sevenbit LED indicator will show "BADx";; (7), if no abnormal condition being found according to the aforesaid step (6), the digital voltage of said battery pack is to be compared and processed continuously to see if said battery pack having fully been charged, and as soon as said battery pack having been charged fully, said buzzer is to be energized, and said LED indicator being also turned off and the charging circuit being turned off simultaneously; (8), if said battery being not fully charged according to the aforesaid step (7), the charging time is to be counted whether said charging time has exceeded T max (i.e., whether the cycle number n2 or n5 has exceeded said n max or not); and if the charging time having exceeded said T max, said battery should be handled in accordance with the abnormal condition step as mentioned in step (6); (9), if said charging time not exceeding T max as described in step (8), further check should be made to see if said two battery packs have been processed completely; and if not, the next battery pack should be processed repeatedly according to said step (3); (10), if said two battery packs not being processed completely, the voltages of said two battery packs should be shown with said printer; (11), said battery packs should be returned to their normal charging steps so as to see if said battery packs being fully charged, and if they being normal or not; and if said two battery packs not being charged completely, said first battery pack should be re-processed through said first channel in accordance with step (3) as mentioned above; (12), if said two battery packs being completely charged according to step (11) mentioned above, check if said two battery packs being removed from the charging device, and after said battery packs being removed, said seven-bit LED indicator should display "AOFF" and said buzzer being also energized and all said LED indicators being turned off to indicate that the charging steps have been finished; (13), if said two battery packs being not removed as mentioned in step (12), see if a t3 time has been exceeded, if not, repeat the step (12);; (14), if said t3 time has been exceeded according to step (13), said buzzer should be energized to send out a warning signal, and to see if the charging time T3 having been exceeded, and if not, said step (12) should be repeated (i.e., said buzzer being energized every t3 period within said T3 time until said battery packs being all removed or said T3 time being over; (15), if said T3 time being over according to step (14) mentioned above, a repeated starting and setting should be made; (16), after a T4 time of preliminary charge, i.e. another quick-pulse charge has been made; and then (17), said step (3) being repeated again to start an automatic and cyclic charge procedures.

45. A central processing unit according to claim 44, wherein the software control flow chart has a step (6), of which said seven-bit LED indicator displays "BADx", and said "x" may be 1 or 2; and when "BAD1" being displayed, it indicates that said first battery packs becoming abnormal; and when "BAD2" being displayed, it indicates that said second battery pack becoming abnormal.

46. A central processing unit according to claim 44, wherein if the second channel of said software control flow chart is modified into fourth channel, and two channels thereof are modified into four channels, and two battery packs are modified into four battery packs, and the charging can be applied to said four battery packs simultaneously.