JPH0458470A - Charge control method for secondary battery - Google Patents

Abstract

PURPOSE:To perform a charge completion control action by detecting the charge completion timing via the state change of a secondary battery before the charge control by a main timer is performed. CONSTITUTION:When a charge is started at the time t0, a main counter 44 starts counting, the state change of a secondary battery 13 due to the charge is checked, if the charge completion timing is detected, a preset charge control action is performed. The detection of the charge completion timing of the secondary battery 13 is preferably performed by checking the change of the battery voltage with a checking means 45. The detecting means 45 of the charge completion timing converts the terminal voltage V3 of the secondary battery 13 inputted via a voltage buffer section 47 into a digital value N1 with a battery voltage detection section 48 having an A/D converter, and the digital value N1 is compared with a memory value N2 outputted from a memory section 50 by the first comparison section 49.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling charging of a secondary battery, and particularly to a method for preventing overcharging.

[Prior art 1] Conventionally, as a charging control method for this scale, the time required for charging is regulated by a timer, and when the timer counts the preset time and reaches the end, charging is forcibly stopped. Common.

In addition, there are various types of devices that utilize the fact that the terminal voltage and surface temperature of the secondary battery rise as charging progresses, detect changes in the state of the battery, determine the end of charging, and perform predetermined charging control operations. Proposed.

[Problem to be solved by the invention] However, in the method of controlling charging m only by time,
It is difficult to accurately know when the battery is fully charged, and there is a strong possibility that there will be excess or deficiency in charging m.

On the other hand, although methods that detect physical changes in the battery can relatively accurately detect the end of charging, it is difficult to perform the detection operation itself accurately, and detection errors can lead to improper control and overcharging. There are also risks.

The present invention has been made to address these disadvantages, and includes:
It is an object of the present invention to provide a charging control method that prevents overcharging.

[Means for Solving the Problems] As shown in FIG. 2, the charging control method according to the present invention reduces the charging time 11 required for the secondary battery 13 to reach full charge from a state where the capacity is small. While charging can be controlled by regulating it with a main timer 44 as shown in FIG. 1, the timing of completion of charging is detected using changes in the state of the secondary battery 13 before the main timer 44 starts charging control. , which enables charging completion control operations.

Furthermore, during the above-described charging, the count value of the main timer 44 is continuously processed unless the secondary battery 13 being charged is removed.

It is preferable to detect the charging completion time of the secondary battery 13 described above by detecting a change in battery voltage, like the detection means 45 shown in FIG.

In addition, the secondary battery 13 during charging is as shown in FIG.
The battery compartment 4 has a lid 15 that can be opened and closed, and can be configured to interrupt the charging operation and the counting operation of the main counter 44 when the lid 15 is opened.

1. With the above-described configuration, when charging is started at time Lo, the main counter 44 starts timing, and at the same time, the state change accompanying the charging of the secondary battery is checked, and when the charging completion time is detected, A predetermined charging control operation is performed.

Here, even if charging is temporarily interrupted, for example, the main timer 44 maintains the count value without resetting it unless the secondary battery is removed and charging is completely terminated. Therefore, even if the above-described detection of the completion of charging does not work, the main timer 44 works appropriately and predetermined charging control is performed at time t3, which is T1 after the start of charging.

[Example] The present invention will be described below based on an example in which two secondary batteries are connected in series and are configured exclusively for charging an assembled battery that is packed together. It goes without saying that the present invention can be implemented in substantially the same manner for the charging means for the secondary battery.

As shown in FIG. 3, a charging device 10 implementing the present invention includes:
On the upper surface 12 side of the approximately rectangular main body case 11, there is an upwardly opening battery chamber 14 that can accommodate four sets of secondary batteries 13 in a freely insertable and removable manner.
At the same time, the opening of the battery chamber 14 is covered with a lid 15 so as to be openable and closable. A charging circuit 16 shown in FIG. 4 is housed inside the main body case 1, and a power plug 17 is extended from the main case 11.
A commercial AC power source 18 can be connected to the charging circuit 16 via 7.

The charging circuit 16 includes a main timer 9 provided on the main body case 11 that applies a commercial AC power source 1B to an inverter circuit 20, and a pulsed charging current output from the inverter circuit 20 through a 3F slipping circuit 21. By smoothing, the charging voltage v1 of about 4.5 to 5.5 [V]
form. This charging voltage v1 is applied to the four sets of charging control circuits 23 via the fuse 22, and the charging voltage is made into a constant current by the charging control circuit 23. Charging current can be supplied to the battery 13 in parallel.

The charging control circuit 23 turns off the charging current control section 24 that directly controls the current value flowing through the secondary battery 13, the correction section 25 that corrects the control ff1 by the control section 24, and the charging current control section 24. It is composed of a charging timing regulating section 26 that allows charging to be stopped.

Full? As shown in FIG. 5, the Ti current control unit 24 connects a high resistance 28 in parallel with the pace emitter of a transistor 27 provided for current control, thereby controlling the pace 7h pressure.
A diode 29 for preventing backflow is connected to the collector side, and a correction section 25 is further provided to the pace side.

The correction unit 25 includes a diode 31 in parallel with the base-emitter terminal of the control transistor 30.
1, the stable voltage 2 output from the constant voltage circuit 32 is applied to keep the base voltage constant, and the base voltage of the transistor 27 is kept constant regardless of fluctuations in the charging voltage V+ output from the smoothing circuit 21. The current flowing through the secondary battery 13 is maintained at a constant current. At the same time, the diode 31 is arranged so as to be in contact with the transistor 27 of the charging current control section 24, so that when the collector current attempts to increase due to a rise in the temperature of the transistor 27, the temperature of the diode 31 also increases at the same time. The base voltage of the correction unit 25 is lowered, the current flowing through the resistor 28 of the charging current control unit 24 is lowered, the base voltage is lowered, and temperature correction is performed to maintain the collector current of the transistor 27 constant.

The charging timing regulating section 26 includes a charging current controlling section 240) and a resistor 2.
A switching transistor 33 connected in parallel with 8 is turned on in conjunction with the human power of a control signal SI output from a control circuit 34 to be described later. 'l [flow control section 24
The transistor 27 is turned off so that charging of the secondary battery 13 can be stopped or limited.

The control circuit 34 uses a one-deep microcomputer, and has a ROM
Its operation is regulated by a program stored in the internal memory, and a functional circuit as shown in FIG. While performing charging control operation, the detection circuit 3
n1 constant control operation is performed in conjunction with the input of the signal output from the display section 36, and a display corresponding to the control content is displayed on the display section 36.
I'm trying to do it with

The display section 36 includes red and green light emitting diodes 37a and 3.
71) are arranged as one set on the main body case 11 for each month's secondary batteries 13 to be charged, and the secondary batteries 13 are removed from the battery compartment 14. The light goes off, and the red light lights up while charging, while the green light lights up when charging is complete and transitions to supplementary charging. Furthermore, secondary battery 1
If an abnormality occurs such as a short circuit in 3, the red color will flash to notify you of the abnormality.

As shown in FIG. 4, the detection circuit 35 includes a circuit voltage detection section that detects the value of the charging voltage vI output from the smoothing circuit 21 and generates a signal S2 when this voltage value exceeds a set value. 38, and the thermistor 3 detects the temperature change of the charging circuit 16.
9 and generates a signal S3 when the temperature rises above a set value.
Control No. 18 S1 is sent to the charging control circuit 23 to charge the secondary battery 1.
3 forcibly stops charging, and the red light emitting diode 37 on the display unit 36 blinks to notify the occurrence of an abnormality. Further, the control circuit 34 outputs a signal S4 corresponding to a period in which the program is operating normally, and the abnormal operation detection unit 41 determines when the signal S4 will stop.
It detects this and sends a reset signal S.5 to the control circuit 34 to return it to the initial state. In addition, the switch 42 can be switched in accordance with the closed position and the open position of the lid 15 covering the battery compartment 14, and the switching state of this switch 12 can be changed to the intership closing timing equipped with an S flip-flop. In place of the two-step signal change S6 in the detection unit 43, the control circuit 34
The open/close state of the lid body 15 is notified to the operator.

As shown in FIG. 1, when the control circuit 34 counts the charging time TI required for the charging capacity of the secondary battery [3 to become fully charged from a zero state, 474 from either one to the control signal generating section 46. If there is human power, a control signal S1 with a duty ratio of 1/16 is sent to the charging control circuit 23, and the charging current control section 24 is turned on intermittently for short periods of time, changing from the rapid charging state to the supplementary charging state. I'm trying to move it.

The above-mentioned charging completion time detection means 45 includes the voltage buffer section 4
7, the terminal voltage ν3 of the secondary battery 13 is
The battery voltage detection unit 48 equipped with an A/D converter detects digital 4
After changing to H+, the first comparison section 49 compares it with the device value N2 configured from the storage section 50. When the detected value N1 is larger than the stored value N2, the first comparison section 49 updates the stored value N2 by replacing the stored value N2 in the storage section 50 with the detected value N+, thereby storing the battery voltage v3 in the storage section 50.
At the same time, a reset signal S13 is sent to the sub-timer 51. The sub-timer 51 sends a timer signal S14 to the second comparing section 52 after counting a time T2 of, for example, about 5 minutes. The stored value N2 corresponds to the period in which
The difference voltage v4 between the detected value N1 and the detected value N1 is compared with the set voltage Vs. Here, when the differential voltage v4 separates the set voltage Vs, a signal S12 is sent from the second comparison section 52 to the control signal generation section 46, and a predetermined control signal S1 is sent from the generation section 46 to the charging control circuit 23. As a result, quick charging ends and supplementary charging begins.

Next, the control operation in the above-mentioned charging device 10 will be explained in more detail according to the flowchart shown in FIG.

When the main timer 19 is turned on to start the charging device 10, the RAM area is initialized in step 101, and then processing step A is entered when the lid 15 of the battery chamber 14 is open.

This process A is performed after charging is temporarily interrupted in step 103 when it is detected in step 102 that the lid 15 is opened during charging, and in step 104, the process shown in FIG. After clearing the data area to be used by the charging completion time detection means 45 shown in FIG. 4, it is checked in step 105 whether or not the secondary battery 13 is removed, and the process waits for the lid 15 to be closed in step 106. When it is determined in step 105 that the battery 13 has been removed, the process moves to step 107 and the main timer 44
At the same time as clearing the count value of
is removed. Further, when it is determined in step 106 that the lid body 15 is closed, step 1.
After performing charging start processing in step 09, step 110
Enter process B starting from .

In this process B, in step 110, it is determined whether the charging is already in the terminal-r state for some reason, and if the charging is in the terminal state, the following processing is not performed.
After performing a predetermined process in step 111, the process waits until the lid 15 is opened and the process returns to step A in step 102.

Conversely, when charging is in progress, in steps 112 and 113, for example, 16 detection data are added and averaged to determine the detected value N1 of the battery voltage. Even if noise is superimposed on the battery voltage, the detection 4
1J N + tJ'5'! Prevents constant high 1N
I'm confused.

Next, in step 114, the count value of the main timer 44 is counted up, and in step 115, when it is determined that the main timer 44 has finished counting -1 - the limit value T+ of the charging time, for example, 75 minutes, Step 11
1. A charging termination process that cycles through 102 and 110 begins.

On the other hand, if it is determined in step 115 that the main timer 44 has not reached the set time T+, then in step 116 -C, it is determined whether or not the detected value N+ of the battery voltage v3 detected in step 113 is normal. judge. Of course, since the two batteries 13 to be charged are connected in series, it is considered normal if the voltage is in the range of 2.0 to 3.5 [V], and if it is 3.5 [V] or more, the battery 13 is connected in series. , it is determined that the charging voltage v1 is being detected as is without the battery 13 being inserted,
Step 111: Enter the charging 17 o'clock loop of ]02 and 110. Furthermore, the detection [4N + is 0.5 to 2.0 [
If the voltage is 0.5 [V], it is determined that one battery is shorted internally, and if it is 0.5 [V] or less, it is determined that both batteries are shorted, and the process moves to step]11. While charging is forcibly stopped, the red LED
7 is blinked and -C abnormality is displayed.

” - In step 11 (S), detect the detected value N of the battery voltage
If it is determined that - is within the normal range, the end-of-charging detection step C starts at step 117. In step C, in step 117, the stored value N2 in the storage unit 50 is compared with the above-mentioned detected value N+whichever is larger or smaller. Here, if the stored value N2 is smaller than the detected value NI, the stored value N2 and the detected value are replaced in step 118, and after clearing the count value of the sub-timer 51 in step 119, the detected data is Initial settings are made, and the process returns to step 112 to perform averaging processing of the detected data.

Conversely, in step 117, the memory jaz2 has the detected value N1.
If it is determined that the stored value N2 is greater than the set time T2, it is determined in step 121 whether the stored value N2 is maintained beyond the set time T2, and if No, the sub-timer 51 is counted up in step 122, and the step At step 123, it is determined whether the count value of the button 51 has reached, for example, the set time T2 of 5 minutes. If 5 minutes is too short, then in step 124, the stored value N2 and the detected value N
It is determined whether or not the differential voltage v4 has reached a set value Vs of about 40 [mV], for example, and if it is YIi, S, it is determined that it has exceeded the peak position at the end of charging, and in step 111 The charging termination process is performed, and the charging of the secondary battery 13 is transferred to supplementary charging, and the green 1,
E I) Lights up 37 to notify that charging is complete. Conversely, if it is determined in step 124 that the set voltage Vs has not been reached, the main timer 4 continues to operate.
4 to karantoi 1 and battery voltage detection 1+ri N
, and if at least one of them is satisfied to an unreasonable degree, it is determined that a fully charged state has been reached, and the process moves to step 11 to end charging.

Note that instead of detecting the charging completion time using changes in battery voltage, it is also possible to detect changes in battery surface temperature or internal gas pressure.

[Effects of the Invention] As described above, the present invention simultaneously detects the charging time using a timer and the charging completion time using changes in the state of the secondary battery, and when either one of the detections is activated, the charging ends. In addition, even if charging is interrupted, the counting operation of the timer continues as long as the +rm battery is not removed from the charging state, thereby reliably preventing overcharging.

Further, the secondary battery 13 is stored and charged in the battery chamber 14 equipped with a lid 15 that can be opened and closed, and charging is stopped when the lid 15 is opened, but the count value of the timer 44 is saved. , when the lid body 15 is closed, the timer 44
By restarting the count, appropriate charging control with no excess or deficiency can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration for implementing the present invention, and FIG. 2 is a graph for explaining control operations. 3 to 6 show an example in which the present invention is implemented in a charging device, FIG. 3 is an external perspective view showing the overall configuration, FIG. 4 is a block diagram showing the configuration of the charging circuit, and FIG. 5 is a block diagram showing the configuration of the charging circuit. The figure is an electric circuit diagram showing the specific configuration of the charging control circuit, and FIG. 6 is a flowchart showing the operation of the control circuit. ] 3 ・ L 4 ・ 15 ・ 23 ・ 44 ・ 46 ・ 49 ・ 50 ・ 51 ・ Secondary battery, 77 battery compartments, i-δ electric control circuit, main timer control signal generation section, first comparison section, storage section, Subtimer invention Akira Makatsu, Nago

Claims (1)

[Claims] 1. The main timer (44) regulates the charging time required to fully charge the secondary battery (13) from a small capacity state, and the main timer (
44) is a charging control method that detects the charging completion time using a change in the state of the secondary battery (13) before the charging control is activated, and enables charging completion control operation, A method for controlling charging of a secondary battery, characterized in that the count value of a main timer (44) is continuously processed unless the secondary battery (13) is removed. 2. Detection of the charging completion time of the secondary battery (13) described above is performed by detecting changes in battery voltage, and the secondary battery (13) being charged is )
The charging control method according to claim 1, wherein the charging control method is housed in a battery chamber (14) having a battery chamber (14), and the charging operation and the counting operation of the main timer (44) are interrupted when the lid (15) is opened.