JP3162540B2 - Charging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rechargeable nickel alloy.
The present invention relates to a charging device for a cadmium battery or the like.

[0002]

2. Description of the Related Art When a battery is charged, a line A shown in FIG.
The battery voltage fluctuates as shown in FIG. That is, at first, the battery voltage rises relatively quickly (see A1), then gradually rises (see A2), the voltage rise rate increases just before the battery is fully charged (see A3), and after the full charge, The battery voltage decreases when charging is continued (see A4). That is, the battery voltage becomes maximum in the fully charged state. Timing the battery voltage by utilizing this phenomenon is maximized, i.e. fully charged form to detect the timing at which the battery voltage starts to descend from the raised
Various techniques for stopping charging in a state have been proposed.

For example, Japanese Patent Application Laid-Open No. 63-234844 discloses a technique in which a battery voltage is detected every predetermined period and charging is stopped when it is found that the voltage has continuously dropped a predetermined number of times or more. Have been. According to this, the charging is stopped immediately after the full charge. However, according to this method, charging of the overdischarged battery is not successful. When the overdischarged battery is charged, the battery voltage once rises rapidly and then falls (see line A6), as indicated by A5 in FIG. Thereafter, the battery voltage increases in the same pattern as the normal battery. According to only the technique of detecting the timing at which the battery voltage changes from rising to falling, when the battery voltage rises according to line A5 and then falls according to line A6, the timing at which the battery voltage becomes maximum is detected, and The charging is stopped in a shortage state.

Various techniques for preventing such malfunctions have also been proposed. For example, according to the technique disclosed in Japanese Patent Application Laid-Open No. 4-58471, it is determined whether or not the battery voltage has reached a maximum while the battery voltage is below a predetermined value. Judgment is not performed.
Japanese Patent Application Laid-Open No. 61-288740 discloses a technique in which it is not determined whether or not the battery voltage has become maximum until the battery voltage starts to stably increase. According to the technique disclosed in Japanese Patent Application Laid-Open No. 63-234844, it is not determined whether or not the battery voltage has changed from rising to falling until a certain time has elapsed after the start of charging.

[0005]

Problems to be Solved by the Invention Japanese Patent Laid-Open No. 4-58471
According to the method of (1), that is, the method of prohibiting the determination of whether or not the battery voltage has become maximum while the battery voltage is equal to or less than a predetermined value, it is difficult to charge batteries having different rated voltages with one charging device. Become. For example, if both the rated 12 volt battery and the 7.2 volt battery can be charged, when the overdischarged 12 volt battery is charged, it is higher than the maximum voltage (V7 in FIG. 1) generated at the initial stage of charging. A predetermined value must be set for the level. However, this makes it impossible to determine whether or not the maximum voltage (V8 in FIG. 1) occurs in the fully charged state of the 7.2-volt rated battery. As described above, in the method of performing or not performing the comparison as to whether or not the battery voltage is the maximum based on the fixed voltage value, batteries having different rated batteries can be charged by the same charging device. Disappears.

[0006] The method of JP-A-61-288740,
That is, until the battery voltage starts to increase stably, it is not determined whether or not the battery voltage has become maximum, or the method disclosed in JP-A-63-234844, that is, until a certain time elapses after the start of charging. According to the method that does not determine whether the battery voltage has become maximum, the line A2 in FIG.
Is determined from the state shown in FIG. Here, the time indicated by the line A2 is a time when the battery voltage is stably rising even though it is gradual, and it should not be erroneously determined whether or not the battery voltage has reached the maximum.
However, in an actual work site, a large motor may be turned on / off near the charging device, and the power supply voltage is likely to fluctuate. Therefore, it is easy for the battery voltage to temporarily drop due to the fluctuation of the power supply voltage at the time indicated by the line A2. This also occurs when the contact state between the battery and the charging device changes. When such a situation occurs, charging is stopped before full charging by these methods, resulting in insufficient charging. JP-A-63-234
According to the system of No. 844, it is necessary to prevent the charged battery from being overcharged when it is recharged.
The timing shown in FIG. 2 is also the determination target period. The present invention solves the above-mentioned problems, and makes it possible to detect the full charge timing of batteries having different rated voltages with one charging device, and to make it difficult to make an erroneous determination even if there is a fluctuation in power supply voltage or the like. .

[0007]

To this end, the present invention has created a charging device whose outline is schematically shown in FIG. Note that the upper half of FIG. 1 shows how the battery voltage varies, taking as an example a case where two types of batteries having different ratings are charged by this device. This charging device is capable of charging two or more types of batteries, but the following description will be given by taking the case of two types of batteries as an example.

[0008] The charging device according to the present invention includes the following means A to D. A. This means detects and stores the battery voltage (V1) when a predetermined time (T1) has elapsed after the start of charging. V1 (A) for battery A, V1 (B) for battery B
Is detected and stored. B. This means uses the battery voltage V1 detected and stored by the A means.
(A) and V1 (B) are compared with a predetermined voltage to divide the battery according to the rated voltage. That is, V1 (A) and V1 (B)
Is compared with a predetermined value to determine whether the battery is an A type battery or a B type battery.

C. This means detects the timing at which the battery voltage changes from rising to falling. In the case of FIG. 1, T2 (A),
The timing such as T2 (B) is detected. However, this means uses the battery voltage detected by the means A, that is, the battery voltages V1 (A), V1 when the predetermined time (T1) has elapsed.
It operates after the value obtained by adding the predetermined potential difference ΔVS to (B), and does not operate before that. The predetermined potential difference ΔVS used here is determined for each rated voltage of the battery. This means that if the battery is an A type battery,
1 (A) + ΔVS (A), V1 for B type batteries
The timing starts to be detected after the battery voltage becomes higher than (B) + ΔVS (B). D. This means stops supplying the charging current when the means C detects the timing. Note that the predetermined time (T
1) becomes substantially equal to the time when the initial voltage fluctuation (that is, the temporary increase shown in line A5 and the temporary decrease shown in line A6) that occurs when the overdischarged battery is charged ends. (The above corresponds to claim 1).

[0010] The means for detecting the timing at which the battery voltage changes from rising to falling includes means for detecting the battery voltage at predetermined intervals, means for extracting and storing the maximum voltage among the detected battery voltages, Means for comparing the detected battery voltage with the maximum voltage, wherein the timing is detected based on whether a battery voltage equal to or smaller than the maximum voltage is continuously detected. (Corresponds to item 2). When the battery voltage equal to the maximum voltage is detected, the battery voltage is determined to be once, and when the battery voltage smaller than the maximum voltage is detected, the battery voltage is detected n times (where n is 2).
It is desirable that the number of times that a battery voltage equal to or smaller than the maximum voltage is continuously detected is set as the above integer (corresponding to claim 3).

[0011]

According to the charging device incorporating the means A to D,
V1 (A), V1 (B) shown in the upper diagram of FIG. 1 (where C1, D... For batteries of type C1, D..., V1 (C), V1 (D)
... etc.) are detected and stored. Here, the predetermined time T1
Is set substantially equal to the time at which the initial voltage fluctuation that occurs when the overdischarge battery is charged ends. Therefore, V1 (A), V
1 (B)... Correspond to the rated voltage of the battery. Means B performs the comparison using the voltages V1 (A), V1 (B),..., So that the charged batteries are accurately classified by the rated voltage.

When the rated voltages are classified, predetermined potential differences ΔVS (A), ΔVS (B)... Are obtained for each of the rated voltages, and for each type of battery, that is, for an A type battery, the battery voltage is V1. (A) + ΔVS (A) until the battery voltage becomes V1 (B) + ΔV for a B type battery.
Until S (B), it is not determined whether or not the battery voltage has reached the maximum. If the battery type is A type, the battery voltage is V1 (A) + ΔVS (A), and the B type battery If, the determination is made after the battery voltage becomes V1 (B) + ΔVS (B). Here, V1 (A) + ΔVS
The value of (A) or V1 (B) + ΔVS (B) becomes substantially equal to the voltage value at the start of the period (the start of line A3) where the voltage rise rate increases immediately before the battery is fully charged. ing.

For this reason, if the means A to D are provided, the timing at which the battery voltage changes from rising to falling after the timing at which the voltage rising rate starts to increase for each rated voltage of the battery is detected. That is, in the case of the A type battery, the process of detecting the phenomenon in which the battery voltage is inverted from rising to falling is not performed not only at the times indicated by the lines A1, A5, and A6, but also during the period indicated by the line A2. Only after the determination, the determination is performed.

After the line A3, the rate of increase in voltage is increasing, and a phenomenon of reversal from rising to falling based on a large voltage fluctuation is detected. Therefore, an accurate full charge timing is detected irrespective of power supply fluctuations. Conversely, the detection process of the full charge timing is executed only under the condition that the detection accuracy of the battery voltage may be relatively low, so that the charging device can be configured with inexpensive components.

The detection of the full charge timing is performed by comparing with the maximum voltage, and when the battery voltage is continuously lower than the maximum voltage, the timing when the battery voltage is inverted from rising to falling is seen, that is, ( A) The battery voltage is detected for each period shown in (A), the maximum voltage is obtained from the battery voltage, and the timing of inversion from rising to falling is detected by using the counter counted by the processing of FIG. The accurate timing of the phenomenon of reversal from ascending to descending is detected against such fluctuations. In particular, when the maximum voltage and the battery voltage are equal to one, and when the battery voltage becomes lower is counted as n (here, n is 2 or more), that is, when the battery voltage becomes lower, the method continues as shown in FIG. Then, when the number of times of descending is counted, the timing of accurately and quickly reversing from ascending to descending is detected.

[0016]

FIG. 3 shows the system configuration of the charging device of the present invention. The current supplied from the commercial power supply 2 is rectified by the rectifying and smoothing circuit 4 and then smoothed.
On / off control. The transformer 8 steps down the commercial voltage and supplies a charging current to the secondary side. This current is rectified by the rectifying / smoothing circuit 9, smoothed, and supplied to the battery 10. The battery 10 includes a plurality of 1.2-volt cells, a 7.2-volt battery containing six cells, a 9.6-volt battery containing eight cells, and a 12-cell battery having 12 batteries. Any of the 0.0 volt batteries is used.

The secondary side circuit is provided with a charging current detecting circuit 12 and a battery voltage detecting circuit 14. Further, a temperature-sensitive switch (specifically, a thermostat) 16 that is turned on / off as the temperature of the battery rises is also provided. These are input to the microcomputer 18. An auxiliary power supply 20 is attached to the transformer 8 and the microcomputer 1
8 is supplied with a power supply voltage. Microcomputer 18
Executes the processing described below in accordance with a predetermined program, and sends the processing result to the primary side control circuit 26 via the photocoupler 24. The primary side control circuit 26 controls ON / OFF of the switching element 6 based on the processing result of the microcomputer 18. A drive voltage is supplied to the primary side control circuit 26 from the auxiliary power supply 22 attached to the transformer 8 .

The microcomputer 18 receives the signal of the charging current detection circuit 12 and adjusts the duty ratio of the switching element 6 so that the charging current has a substantially constant value. 4 and 5, the switching element 6 is fixed to OFF when the battery 10 is fully charged. The processing in FIG. 4 shows a processing procedure executed by the microcomputer 18 and corresponds to step S0.
As shown in (2), an interrupt is executed when a predetermined time (T1) has elapsed after the start of charging.

The predetermined time (T1) is a predetermined time, and is a time at which the initial voltage fluctuation shown by lines A5 and A6 in FIG. 1 is almost completed. After a lapse of T1 time from the start of charging, the battery voltage takes a value well corresponding to the rated voltage of the battery, regardless of the degree of discharging at the start of charging. On the other hand, the battery voltage at the start of charging may not be related to the rated voltage. For example, the battery voltage V00 (A) of the rated voltage of 12 volts is changed to the battery voltage V0 of the rated voltage of 7.2 volts.
It may be lower than (B). When the time T1 elapses after the start of charging, the above-mentioned problem is solved, and the initial voltage fluctuation that occurs when the overdischarged battery is charged has also subsided. I have.

The process of FIG. 4 is programmed to be executed when a predetermined time (T1) has elapsed after the start of charging based on such knowledge. First, in step S2, the battery voltage at that time is detected and V1 is detected. To be stored. Step S
By the processes of 0 and S2, means A for detecting and storing the battery voltage when a predetermined time has elapsed after the start of charging is realized.

Next, at step S4, the detected battery voltage V1 is compared with a predetermined voltage. The charging device of this embodiment is rated at 7.2 volts, 9.6 volts, and 12.0 volts.
It is planned to charge a battery having three rated voltages of volts, and V9.6L, 9.6 volts, and 12.12 as predetermined voltages for dividing 7.2 volts and 9.6 volts.
V9.6U is used as a predetermined voltage for classifying 0 volt. V9.6L uses 9.6 volt battery
V9.6U is a value slightly higher than the maximum voltage, which is slightly lower than the lowest voltage among the battery cells generated when the battery is charged for one hour. If V1 ≦ V9.6L, rating 7.
A 2 volt battery is charged and V9.6L <V1 <
If V9.6U, a battery with a rated 9.6 volt is charged, and if V1 ≧ V9.6U, a battery with a rated 12.0 volt is charged.

By the processing in step S4, the battery voltage (V
Means B is configured to compare 1) with a predetermined voltage to classify the battery according to the rated voltage. In FIG.
Step S6 is performed when the battery is a 2 volt battery, step S8 is performed when the battery is a 9.6 volt battery, and step S10 is performed when the battery is a 12.0 volt battery. Steps S6, S8, and S10 add a value ΔVS (7.2) defined for each rated voltage of the battery to the predetermined potential difference ΔVS,
ΔVS (9.6) and ΔVS (12.0) are stored, respectively.

After the above processing is completed, the processing is temporarily terminated (step S12). Next, when a predetermined period has elapsed, FIG.
Is executed by interruption. The process of FIG. 5 is thereafter executed every predetermined period (S14). First, step S1
The battery voltage is read in step 6 and set to VN (step S1).
6). Next, the current battery voltage VN is changed to the maximum voltage VP so far.
Compared with EAK, if the current battery voltage exceeds the maximum voltage up to now, that is, if step S18 is NO, the current voltage VN is set to the maximum voltage VPEAK (step S18).
20). If the current maximum voltage VPEAK is higher, step S20 is skipped. While the voltage is increasing, that is, while VN> VPEAK, the value of the counter is set to zero (step S22). While the voltage is increasing, the processing after step S24 is not executed, and the process is temporarily terminated (step S36).

When the current battery voltage VN is equal to or smaller than the maximum voltage VPEAK up to that time, step S24 is executed. Here, a value obtained by adding a predetermined potential difference (ΔVS) to the battery voltage (V1) when a predetermined time (T1) has elapsed after the start of charging is compared with the battery voltage (VN). Here, V1 is stored in step S2 of FIG. ΔVS is set in one of steps S6, S8, and S10 according to the rated voltage of the battery.

The processing in step S24 is performed in step S26.
This is for determining whether or not to skip the subsequent processing. The processing is skipped during no and executed when the determination is yes. The processing after step S26 is for detecting the timing at which the battery voltage VN changes from rising to falling. Therefore, if the current battery voltage VN is smaller than the maximum voltage VPEAK, the value of the counter is advanced by two (step S
28) If they are equal, advance by one (step S30)
(Note that VN> VPEAK does not occur in step S18.) As a result, the number of times that the relationship of VN ≦ VPEAK is continuously detected is counted by the counter. At this time, when VN = VPEAK is defined as one time,
When N <VPEAK, it is counted as two times. When it is surely falling, it counts with weight.

The number counted as described above is compared with a predetermined number in step S32. VN ≦
If VPEAK continues, charging is stopped in step S34. That is, the switching element 6 is kept in the off state. If the value of the counter has not reached the predetermined number of times, step S32 is NO, and the process of FIG. 5 is repeated. When VN> VPEAK, step S18 is NO and the counter is cleared to zero (step S2).
2). In other words, even if VN ≦ VPEAK by this processing, charging is not stopped unless charging is continued, and processing for stopping charging when continued is executed.

As described above, when VN <VPEAK, and it is known that there is a certain fall, the weight is counted and counting is performed so that step S32 quickly becomes YES. In this embodiment, the counter is incremented by two in step S28.
You may step forward.

In the case of this embodiment, steps S26 to S26 are executed.
S32 constitutes a means for detecting the timing at which the battery voltage changes from rising to falling, and this processing is executed only when step S24 is YES, so that the battery voltage (VN) is reduced. The predetermined time (T
1) A predetermined potential difference (ΔVS) to the battery voltage (V1) at the time of elapse
After that, the timing detecting means operates after the voltage becomes equal to the sum of the voltages. Step S34
Is a means for stopping the charging current.
This is executed when the reversal phenomenon from ascending to descending is detected by 26-32.

The advantages of this embodiment will be described with reference to FIG. In the case of this embodiment, when the voltage rise rate becomes large immediately before the full charge state, the inversion from the rise to the fall is detected. That is, the inversion is detected when the voltage fluctuation within the predetermined period is large. For this reason, the voltage detection accuracy may be relatively rough. For example, the voltage fluctuation of the solid line may be originally detected as a broken line (the broken line has a coarse resolution). If the detection resolution is low, there is no erroneous detection that a reversal phenomenon from rising to falling has occurred by a small change in the battery voltage. If the resolution is coarse, detection delay may be a concern. In the present embodiment, not only VN <VPEAK but also VN = VPEAK is included in the count. Therefore, the counter advances after the timing of X in FIG.
It is possible to detect a timing that is very close to the timing of the inversion from rising to falling.

As described above, according to the present embodiment, the timing detection performance does not deteriorate even with a coarse resolution. Of course, since coarse resolution is sufficient, it is possible to use inexpensive electronic components and the like. Note that in order to detect the timing of inversion from rising to falling, a voltage fluctuation difference for a predetermined period is taken, and after it changes from plus to minus, it may be checked whether or not the minus fluctuation has continued a predetermined number of times. Good. However, in this method, erroneous detection may be caused by a slight fluctuation of the power supply voltage. On the other hand, in the present embodiment, erroneous detection hardly occurs because the voltage is compared with the maximum voltage instead of the voltage fluctuation within the predetermined period.

In the case of this embodiment, step S24 in FIG.
May be determined, the extraction processing of the maximum voltage in steps S18 to S20 may be executed. Further, the processing of FIG. 7 may be added. That is, a means for operating after the battery voltage becomes a voltage obtained by adding the predetermined potential difference (ΔVS) to the battery voltage (V1) at the lapse of the predetermined time (T1), and detecting the timing at which the battery voltage changes from rising to falling. It may consist of a plurality of means.

A step S72 detects a timing at which the voltage fluctuation ΔV within a predetermined period becomes a value obtained by subtracting a fixed value from the maximum fluctuation ΔVMAX. If a constant value is set as an appropriate value for each rated voltage of the battery, step S72 can be set to be YES just before the timing when the battery voltage changes from rising to falling. Steps S26 to S32
, Or in conjunction with S26 to S32 in step S
72 can be used. Similarly, in step S74, the inversion timing from the rise of the battery voltage to the fall can be detected. After the battery is fully charged, it has a characteristic that the temperature rises suddenly. If the thermostat is set at this temperature, step S7
4, the full charge timing can be detected.

Step S76 is to check the timing when the battery voltage VN becomes lower than the maximum voltage VPEAK by a predetermined value (ΔVC). If the absolute value of ΔVC is set to a small value, the battery is fully charged. You can see that it has become. Steps S26 to S32, S72, S74, S
The present invention can also be embodied by executing one or more of the steps 76 only when step S24 is YES.

[0034]

According to the present invention, it is easy to detect the timing at which the battery voltage fluctuates greatly and changes from rising to falling,
At the same time, full charge is detected only under conditions that are unlikely to be erroneously detected, so that stable detection can be performed, and inexpensive components with a coarse detection resolution can be used.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing the configuration and operation of the present invention.

FIG. 2 is a diagram schematically showing the configuration and operation of the present invention.

FIG. 3 is a system diagram of an embodiment.

FIG. 4 is a processing procedure diagram of an embodiment.

FIG. 5 is another processing procedure diagram of the embodiment.

FIG. 6 is a diagram for explaining the operation of the embodiment.

FIG. 7 is a diagram showing a modification of the embodiment.

[Explanation of Signs] A: Means for detecting and storing battery voltage when a predetermined time has elapsed after the start of charging B: Means for classifying batteries by rated voltage C: Adding a predetermined potential difference to the voltage when the battery voltage has elapsed a predetermined time Means for detecting the timing at which the battery voltage changes from rising to falling after the voltage has dropped to D: charge stopping means

Continuation of front page (56) References JP-A-4-58734 (JP, A) JP-A-64-81629 (JP, A) JP-A-63-234844 (JP, A) JP-A-61-288740 (JP, A) JP-A-5-49183 (JP, A) JP-A-64-47232 (JP, A) JP-A-4-58471 (JP, A) JP-A-63-124729 (JP, A) JP-A-2-219424 (JP, A) JP-A-4-88836 (JP, A) JP-A-4-1455841 (JP, A) JP-A-4-355633 (JP, A) A) U.S.A. 3-106846 (JP, U) U.S. Pat. No. 5,516,645 (JP, U) U.S. Pat. No. 4,693,655 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02J 7 / 00-7/12 H02J 7/34-7/36 H01M 10/42-10/48

Claims (3)

(57) [Claims] An apparatus for charging a battery by supplying a charging current to the battery, means for detecting and storing a battery voltage (V1) when a predetermined time (T1) has elapsed after the start of charging, Means for comparing the battery voltage (V1) with a predetermined voltage to classify the battery according to the rated voltage; and a voltage obtained by adding a predetermined potential difference (ΔVS) to the battery voltage (V1) after the lapse of the predetermined time (T1). It operates after the time when becomes, means for detecting the timing when the battery voltage changes from rising to falling, and means for stopping the supply of the charging current when the timing detecting means detects the timing. The predetermined time (T1) is substantially equal to the time at which the initial voltage fluctuation occurring at the time of charging the overdischarged battery ends, and the predetermined potential difference (ΔVS) is determined for each rated voltage of the battery. Charging device according to claim. 2. The charging device according to claim 1, wherein the timing detecting means detects a battery voltage at predetermined time intervals, and extracts and stores a maximum voltage among the detected battery voltages. Means for comparing the detected battery voltage with the maximum voltage, wherein the timing is detected based on whether a battery voltage equal to or smaller than the maximum voltage is continuously detected. And a charging device. 3. The charging device according to claim 2, wherein a battery voltage equal to the maximum voltage is detected once, and a battery voltage smaller than the maximum voltage is detected n times. Where n is an integer of 2 or more), and the number of times that a battery voltage equal to or smaller than the maximum voltage is continuously detected.