JPH0437660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a charging device that charges a battery using constant current source output.

(b) Conventional technology Conventionally, multiple batteries (for example, NiCd batteries)
There is a method for charging a plurality of batteries (including a battery pack having a large number of NiCd batteries) individually and sequentially.

For example, in Japanese Patent Application Laid-Open No. 56-110446, there are several
Each time a NiCd battery block is detected to be fully charged, it starts charging the next battery block, and when a short battery is connected, the charging device detects this and starts charging the next battery block. has been done.

(C) Problems to be Solved by the Invention In the prior art, batteries are sequentially switched in a fully charged state or in an abnormal charging state due to a short battery, and abnormal charging and overcharging can be prevented. There is no suggestion about the labeling.

Also, the document “Nationol Technical Report”
(VOL, 27, No. 6, Dec, 1981) P152 discloses a technology that makes it possible to identify the fully charged state by making the LED, which flashes during charging, turn on when fully charged. However, there is no indication of abnormal charging status. Therefore, in the prior art, it is not possible to determine whether charging of a battery has been interrupted due to an abnormal charging state or whether charging has been completed due to a fully charged state, resulting in an inconvenience.

(d) Means for Solving Problems The present invention is a charging device, which includes a charging abnormality detection circuit that detects an abnormal charging state of a battery, and a full charge detection circuit that detects that the battery has reached a fully charged state. and display means for distinguishing and displaying the abnormal charging state and the fully charged state.

(E) Effect Since the present invention is configured as described above, it can be determined whether the suspension of battery charging is due to a charging abnormality or due to full charging.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

1 is an AC pack (power supply circuit) which is a power source and supplies a constant current power output.

2 is an AC pack insertion detection circuit. As mentioned above, the AC pack has the same shape as the battery and can be used by being housed in the battery connection part of a device that uses the battery. Therefore, there is a risk that the AC pack and battery may be connected to the charging device by mistake, and if a battery other than the constant current circuit is connected to the position of the AC pack, if the battery terminal is shorted, a large current will cause charging. The device is destroyed. In order to prevent this, it is detected whether the AC pack 1 is connected to a predetermined position.

4 is a reverse current detection circuit, and if the voltage of the power line 5 decreases due to a power outage or the like during battery charging, there is a risk that current will flow backward from the power line 6 side to the power line 5 side. , 6 are compared to detect the reverse current.

The power supply voltage control circuit 3 uses the detection outputs from the AC pack insertion detection circuit 2 and the reverse current detection circuit 4 to
If the AC pack is not connected to a predetermined position and reverse current is detected, the constant current power output from the AC pack 1 is blocked from being supplied to the battery.

Reference numerals 7, 8, and 9 are output changeover switches whose opening and closing are controlled by control signals from a sequential changeover circuit 10, which will be described later, and which are connected to a power supply line 6 and batteries 11 and 1, respectively.
It is interposed between 2 and 13.

A battery connection detection circuit 14 detects whether or not the batteries 11, 12, 13 are connected to the terminals 7a, 8a, 9a.

15 is sequentially reset by the control signal of the switching circuit 10. For example, in the case of a battery that can be quickly charged in 60 minutes, it will issue a timer output after 70 minutes, and overcharging will continue even after full charging due to malfunction. This is a protective timer circuit to prevent this from happening.

20 determines whether or not the charging voltage reaches a first reference level (a charging voltage level that an over-discharged battery can reach in this short period of time from the start of charging), and ensures that each battery is in a completely shorted state. This is a first shot detection circuit that detects a certain situation.

21 is a second short detection circuit that determines whether or not the charging voltage reaches a second reference level after a certain period of time after detection by the first short detection circuit 20, and detects that each battery is in a partial short state. be. Here, the battery is 5 pieces of 1.2V.
The case where at least one of NiCd batteries is in a shorted state is called a partially shorted state, and the second reference level is set in advance to a voltage value that cannot be reached in this partial shorted state. There is.

A battery insertion detection switch 17 mechanically detects whether or not a battery is inserted into the device position corresponding to the terminals 7a, 8a, and 9a.

18 is a full charge detection unit that detects a change in the output voltage of terminals 7a, 8a, and 9a, that is, a drop in the charging voltage by △V from the steady state, and determines that the battery being charged has reached a fully charged state. It is a circuit.

The sequential switching circuit 10 is a battery connection detection circuit 1
4. A control signal is generated based on the outputs of the protection timer circuit 15, the first and second short detection circuits 20 and 21, the battery insertion detection switch 17, and the full charge detection circuit 18. That is, the battery connection detection circuit 14 selects the output changeover switches 7, 8, and 9 that should issue a control signal, and the full charge detection circuit 18 determines that charging of the battery being charged is completed, and the battery is discharged. The first insertion detection switch 17 transfers the charging operation to another battery that is confirmed to be installed, and the first and second short detection circuits 20 and 21 and the battery connection detection circuit 14 detect short batteries or disconnected batteries. The power output is prevented from being supplied to a terminal that is determined to be erroneously connected.

A control signal S1 is issued to the output terminal 10a of the sequential switching circuit 10. This control signal S1 controls the opening and closing of the output selector switch 7, and also controls the red
It also becomes the driving voltage for the LED 30. That is, when the control signal S1 is at H level, the output changeover switch 7 is opened, and the charging voltage of the power line 6 is supplied to the battery 11, and the red LED 30 is turned on to indicate that charging is in progress. Similarly, control signals S2 and S3 are issued to the output terminals 10b and 10c of the sequential switching circuit 10, and the output switching switches 8 and 9 are controlled to open and close by each control signal, and charging of the batteries 12 and 13 is permitted. Along with
Red LEDs 31 and 32 are lit to indicate that charging is in progress. Note that the control signals S1, S2, and S3 are never output at the same time.

Next, a display means for distinguishing between a fully charged state and an abnormal charging state will be explained.

The output of the battery connection detection circuit 14 passes through the switch circuit 33 to the first and second short detection circuits 2.
It is input to the OR gate 34 along with the 0 and 21 outputs,
Furthermore, the OR gate 34 output is combined with the control signal S1.
is input to AND gate 35, and this AND gate 3
5 output passes through the high level holding circuit 36 to the oscillator 3.
7. This oscillator 37 generates an output of H←→L at a preset frequency, for example, every 1 second, which is input to the green LED 39 via an OR circuit 38. In addition, the high level holding circuit has an input level of L.
→ Once it shifts to H, it will remain H until it is reset.
Hold level output.

Therefore, when the battery 11 is being charged,
That is, when the control signal S1 is at H level, the output selector switch 7 is open, and the red LED 30 is lit, the first short detection circuit 20 detects that the battery 11 is completely short. When the two-shot detection circuit 21 detects that the battery is in a partial shot state, or the battery connection detection circuit 14 detects that the battery 11 is disconnected, the output of the OR gate 34 becomes H level. In response to this, the high level holding circuit 36 will hold the H level, and while this H level is held, the oscillator 37 will be driven and the green LED 39 will blink. At the same time, the high level holding circuit 36 output of H level is OR
The signal is input to the input terminal 10d of the sequential switching circuit 10 through the gate 40, and causes the sequential switching circuit 10 to detect that the battery 11 is in an abnormal charging state. Further, the control signal S1 changes from H to L immediately when a charging abnormality is detected by the output of the first and second shot detection circuits 20 and 21 or the battery connection detection circuit 14, and the control signal S2 changes from L to H. Then, charging of the battery 12 is started. The timing at which the control signal S1 changes from H to L is set after the high level holding circuit 36 latches the H level. When the control signal S1 becomes L level, the output changeover switch 7 is closed, charging of the battery 11 is stopped, and the red LED 30 is prevented from lighting up.

Similarly, for batteries 12 and 13, OR
The gate 34 output is inputted to AND gates 41 and 42 together with control signals S2 and S3, respectively, and high level holding circuits 43 and 44, oscillators 45 and 46, and OR
It is input to the green LEDs 49 and 50 through the gates 47 and 48, and when a charging abnormality occurs, the charging of the batteries 12 and 13 is stopped and at the same time the red LED
Stop lighting LED31, 32, green LED49,
Make 50 flash. Furthermore, the outputs of the high level holding circuits 43 and 44 are sequentially inputted to the input terminals 10e and 10f of the switching circuit 10 via the OR gates 51 and 52, and the batteries 12 and 13 are in a charging abnormal state and the green LEDs 49 and 50 are in a blinking state. It is made to detect whether or not.

On the other hand, the full charge detection circuit 18 output and the protection timer circuit 15 output are together with the battery connection detection circuit 14 output obtained via the switch circuit 33.
is input to the OR gate 53, and this OR gate 53
The outputs are input to AND gates 54, 55, and 56 together with control signals S1, S2, and S3, respectively. AND
Gate 54 output is high level holding circuit 57/OR
The signal is supplied to a green LED 39 through a gate 38.

Therefore, when the control signal S1 is at H level and the battery 11 is being charged, the full charge state is reached by the full charge detection circuit 18, the protection timer circuit 15, or the battery connection detection circuit 14 as described later. When it is detected that the
The output becomes H level, and the AND gate 54 output becomes H level. The high level holding circuit 57 holds this H level and the green LED 39 lights up.

At the same time, the sequential switching circuit 10 is connected to the full charge detection circuit 1.
8. In response to the output of the protection timer circuit 15 and the battery detection circuit 14, when the battery 11 reaches full charge, the control signal S1 changes from H to L, and the control signal S
2 from L to H to start charging the battery 12. Along with this, the red LED 30 turns off.

Similarly, for batteries 12 and 13, OR
The gate 53 output together with control signals S2 and S3
The outputs of the AND gates 55 and 56 are input to the high level holding circuit 58,
59・Green LED 4 via OR gates 47 and 48
9 and 50, and when each battery reaches a fully charged state, the green LEDs 49 and 50 are turned on.

The high level holding circuits 57, 58, 59 outputs are the same as the high level holding circuits 36, 43, 44 outputs.
The signals are sequentially input to input terminals 10d, 10e, and 10f of the switching circuit 10 via OR circuits 40, 51, and 52, and the switching circuit 10 is made to sequentially recognize which battery is the fully charged battery. Sequential switching circuit 10
receives the outputs of OR gates 40, 51, and 52, and always recognizes batteries that are in an abnormal charging state or fully charged state, and when the battery currently being charged becomes abnormally charged or reaches full charge, it charges the next battery to be switched to. Specify items that are already recognized to be in an abnormal state or fully charged state, excluding those that are already recognized as being in an abnormal state or a fully charged state. for example,
If the battery 12 is recognized in advance as being in an abnormal charging state and the green LED 49 is blinking, the battery 11 is charged and reaches a fully charged state.
When the control signal S1 changes from H to L, the control signal S3
changes from L to H and charging of the battery 13 is started. In this case, the control signal S2 is maintained at L level.

Resetting the high level holding circuits 36 and 57 is as follows:
Set the battery insertion detection output S4 of the battery insertion detection switch 17 (LOW active) to H.
level. Similarly, the high level holding circuit 43,
58 resets the battery insertion detection output S5 of the battery 13 to H level, and the high level holding circuits 44, 5
9 reset is the battery insertion detection output S
This is done by setting 6 to H level. That is, this can be done either by replacing the battery that is fully charged or displaying a charging error, or by resetting the power supply of the system itself.

Next, the battery connection detection circuit 14 will be described in detail with reference to a specific circuit diagram as shown in FIG.

3 is a power supply voltage control circuit, which includes a first transistor Tr1, a second transistor Tr2, a Zener diode ZD, and resistors R1 and R2. 1st
The collector of transistor Tr1 is battery 11
is connected to the charging terminal 7a of the battery, and supplies charging current. The second transistor Tr2 is the first transistor
In order to control the state of Tr1, the collector is connected to the base of the first transistor Tr1, the anode of the Zener diode ZD is connected to the connection point of the resistors R1 and R2, and the cathode is connected to the power line 5 of the AC pack 1. . Resistors R3 and R4 are connected in series between the emitter side of the first transistor Tr1 and the ground, and the connection point of the resistors R3 and R4 is connected to the positive terminal of the comparator 80 and to the collector of the first transistor Tr1. The side is connected to the negative side terminal of the comparator 80. 7 is an output selector switch;
A control signal S1 from the sequential switching circuit 10 is applied to the terminal p, which is the base of the third transistor Tr3.

Note that the collector side of the first transistor Tr1 is also connected to the charging terminals of the batteries 12 and 13 (not shown). In addition, the output of the comparator 80 is output to the switch circuit 3 as the output of the battery connection detection circuit 14.
3.

The timer circuit 81 is used as a timer setting time.
It is set to 2 seconds and is reset each time the control signals S1, S2, and S3 are issued, that is, each time the battery to be charged is switched. The switch circuit 33 is controlled by the output of this timer circuit 81, and in the initial state, the movable contact piece 33a is placed on the fixed contact 33b side.
When the timer circuit 81 output is generated, the fixed contact 3
Switch to 3c side. Therefore, the output of the battery connection detection circuit 14 is input to the OR gate 34 only for 2 seconds immediately after the battery is switched and charging is started, and is input to the OR gate 53 after 2 seconds have elapsed.

To explain the operation of the battery connection detection circuit 14, while the battery 11 is being charged, the third transistor Tr3 is conductive and a charging current flows through the first transistor Tr1, so there is a potential difference of around 100 mV between the emitter and collector of the first transistor Tr1. occurs. At this time, the level of the positive terminal input of the comparator 80 is higher than that of the negative terminal input, and the comparator 80
0 output becomes H level.

Due to disconnection or poor connection of the battery 11, the charging terminal becomes open, and the potential difference between the emitter and the collector of the first transistor Tr1 almost disappears.
At this time, a resistor R is connected to the positive terminal input of the comparator 80.
Since the voltage value divided by 3 and R4 is applied, the output of the comparator 80 becomes L level, which means that a disconnection or poor connection has been detected.

By the way, if you use a high capacity battery and charge it at a low temperature, the charging voltage may reach a value almost close to the maximum output voltage value Emax of AC pack 1 just before reaching the fully charged state. At this time, the potential difference between the emitter and collector of the first transistor Tr1 becomes small, and the output of the comparator 80 becomes L level even though there is no charging abnormality. Therefore, in order to detect disconnection or poor connection within 2 seconds after the start of charging, the output of the battery connection detection circuit 14 is input to the OR gate 34 only in the initial stage of charging. After 2 seconds have passed from the start of charging, the switch circuit 33 is switched to the fixed terminal 33b side by the output of the timer circuit 81 in order to prevent false detection of charging abnormality near full charge as described above, and the output of the battery connection detection circuit 14 is switched to the fixed terminal 33b side. is input to the OR gate 53 and used to detect the fully charged state.

In this embodiment, the fixed terminal 33b of the switch circuit 33 is connected to the input of the OR gate 53, but this connection is blocked and full charge detection is performed only by the output of the full charge detection circuit 18 and the protection timer circuit 15. It goes without saying that you can do it the other way.

(G) Effects of the Invention As described above, the present invention is effective because it can clearly distinguish between a charging abnormal state due to a short or disconnection and a fully charged state in a wide range of batteries including high-capacity batteries. .

Additionally, for batteries that have been determined to be charging abnormally or fully charged, the sequential switching circuit always recognizes this, so even if sequential charging is performed again, these batteries will not be charged. This is effective because it minimizes the time required for sequential charging and improves safety.

[Brief explanation of drawings]

The drawings all relate to one embodiment of the present invention, with FIG. 1 being a circuit block diagram and FIG. 2 being a main part circuit diagram. 1... AC pack (constant current source), 11, 12, 1
3...Battery, 14...Battery connection detection circuit (charging abnormality detection circuit), 18...Full charge detection circuit, 20...First shot detection circuit (charging abnormality detection circuit), 21...Second shoot detection circuit (Charging abnormality detection circuit), 30, 31, 32...Red
LED (display means), 39, 49, 50...green
LED (display means).

Claims (1)

[Scope of Claims] 1. A sequential switching circuit that selectively switches the supply of a constant current source output to a plurality of batteries and sequentially charges the batteries one by one; a charging abnormality detection circuit for detecting; a full charge detection circuit for detecting that at least one of the plurality of batteries has reached a fully charged state; and a charging abnormality or full charge state once determined by the charging abnormality or full charge detection circuit. The sequential switching circuit recognizes the display state of the display means and selects one of the two states for each battery detected to be in one of the two states. A charging device characterized by skipping a battery that is once identified as being present and sequentially charging the battery.