JP3203538B2 - Battery charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charger for detecting full charge and battery mounting by monitoring terminal voltage and charging current without providing a battery mounting detection switch.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing an example of a block configuration of a conventional battery charger. As shown in the figure, a conventional battery charger 1 has a power supply unit 11 for converting AC 100 V to DC and outputting a constant DC voltage, a charge control unit 12 for monitoring a charge state of a battery 2, and a resistor for detecting a charge current. The battery 13 is composed of a detector 13 and a detection switch 15 for detecting whether or not the battery 2 is mounted.

[0005] The power supply section 11 is composed of a constant voltage charging circuit 111 and an output switch 112. The charging control unit 12 includes a current detecting unit 122, a voltage detecting unit 123, and a mounting detecting unit 124.
The determination unit 121 monitors the current detection unit 122, the voltage detection unit 123, and the attachment detection unit 124, determines the charge state and the attachment state of the battery 2, and outputs the output switch 112 to the power supply unit 11. An off signal is output to indicate (omitted) full charge and the like.

Hereinafter, the operation of the battery charger 1 will be described. The output switch 112 of the power supply unit 11 is always off. The battery charger 1 detects when the battery 2 is attached to the charging terminal 14 by the detection switch 15 and sends a detection signal to the charging control unit 12. When the charging control unit 12 detects that the battery 2 has been mounted by the determination unit 121 via the mounting detection unit 124, and further checks the voltage of the battery 2 by the voltage detection unit 123, the charging control unit 12 sends a signal of turning on the output switch 112 to the power supply unit 11. Output. The power supply unit 11 turns on the output switch 112,
A charging current is passed through the resistor 13 to start charging.

[0005] The charging current decays with time as shown by the solid line c in FIG. The initial constant current is due to the upper limit of the charging current. When the current detector 122 detects that the charging current falls within the range of threshold A ₂ ≦ charging current ≦ threshold A ₁ , the determiner 121 determines that the battery is fully charged, and outputs a signal to the power supply 11 to turn off the output switch 112. Display of full charge (not shown). Power supply unit 11 is output switch 1
12 is turned off to complete charging. Incidentally, when the battery 2 is extracted in the course of the charging operation, the charging current may change in the middle as indicated by the dotted line d in FIG. The charging current ≦ threshold A _2.

[0006]

However, in the conventional battery charger, since a detection switch (or a mounting detection terminal) for detecting the mounting of the battery is provided, the number of parts increases, the cost increases, and the electrical connection and mechanism are increased. The mechanism design for designing the order of the mechanical contact becomes complicated. In addition, the case of the battery charger 1 requires a switch hole (or terminals) and the like, so that the shape is complicated, and there is a problem that the battery charger 1 is susceptible to failure due to external factors such as mechanical or static electricity.

[0007] In addition, to determine whether the battery 2 is fully charged or not by monitoring the charging current and the inter-terminal voltage, erroneous detection due to an unstable contact state of the fitting when the battery is mounted, or vibration of the charging current. It becomes a problem to remove the erroneous detection of the full charge due to the above and the like and to make a reliable determination.

The present invention has been made in view of the above points, and has a simple structure to eliminate the above-mentioned problems. By checking the charging current and the voltage between the charging terminals, it is possible to securely mount and maintain the battery. It is an object of the present invention to provide a battery charger capable of detecting a full charge.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a method of connecting a battery to a charging control unit having a charging current detecting unit for detecting a charging current of a battery and a voltage detecting unit for detecting a voltage of the battery. In a battery charger having a charging terminal for charging a battery, a charging control unit reads a charging current detected by a charging current detecting unit and a voltage between terminals detected by a voltage detecting unit, and the battery is mounted. And a full-charge determining unit that determines whether charging is completed based on the value of the charging current. The full-charge determining unit includes a threshold value of a charging current when the battery is fully charged. current value Ax and the current value Ay in the vicinity of a ₁
(Ax> Ay), a charging current band of full charge is set, and it is determined that the charging current detected by the charging current detection unit has passed the charging current band to determine that charging is completed.
When the charge current decreases without detecting the passage of the full charge current band, a function is provided for determining that the battery has been removed from the battery charger.

[0010]

The charging current monitoring type battery charger of the present invention utilizes the characteristic that the charging current decreases as the charging of the battery progresses as shown in FIG. , Detection switches (or mounting detection terminals) for battery mounting detection are not required, the number of components is reduced, the mechanism design is easy, and the cost is reduced. In addition, the number of holes for switches (or terminals) in the case of the battery charger is reduced, the shape is simplified, and failure due to mechanical or external factors such as static electricity is increased.

As described above, since the voltage between the charging terminals 14 and the charging current are alternately and repeatedly checked, erroneous detection is also made when the fitting of the battery mounting mechanism is poor or when the operation of the hard is unstable. It is possible to reliably detect that the battery 2 is mounted.

In addition, the current band (A) near the full charge threshold
x to Ay), and the charging current is set to a current band (Ax to Ay).
Since it is determined that the battery is fully charged (charging is completed) by detecting the passage of y), it is possible to reliably determine without erroneous detection due to the influence of vibration of the charging current or the like.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a block configuration of a battery charger of the present invention. As shown in the figure, a battery charger 1 of the present invention converts AC 100V to DC and outputs a constant DC voltage, a power supply unit 11, a charging control unit 12 for monitoring a charging state of the battery 2, and a charging current detecting unit. , And charges the battery 2 through the charging terminal 14. In the present invention, the components (switches) for detecting the attachment of the battery 2 are removed from the above-described conventional example, and processing is performed by software (program). In addition,
1 that have the same reference numerals as those in FIG. 5 represent the same functions as those in FIG.

The battery charger 1 of the present invention detects when the battery 2 is mounted and detects the
Is turned on to start charging, and when the battery 2 is fully charged (charging is completed), the output switch 112 is turned off and a display (omitted in the figure) is performed. Hereinafter, a method for determining whether or not the battery is mounted will be described.

First, when the battery 2 is first mounted (the output switch 112 is in the OFF state), the charging control unit 12 turns on the output switch 112 when the voltage detecting unit 123 detects the voltage between the charging terminals 14, 2 and a charging current is passed. When the value of the charging current is higher than the threshold value A ₁ (see FIG. 4) of the charging current at the time of full charging, it is determined that the battery 2 is mounted, and the charging is continued.

[0016] If the value of the charging current is lower than the threshold value A ₁ is,
Further, in order to confirm whether an erroneous detection due to an unstable contact state when the battery is mounted or whether the fully charged battery 2 is mounted, the output switch 112 is turned off once and the charging terminal 14 is turned off. measuring the voltage, turns on the output switch 112 again to check the battery voltage, it determines that the battery 2 reconfirm to fully charged state that the value of the charging current is lower than the threshold value a ₁ at that time is attached I do. As described above, even when the battery mounting mechanism is improperly fitted or when the operation of the bird is unstable, the voltage between the charging terminals 14 and the charging current are alternately repeated to reduce erroneous detection. It is possible to detect that the battery 2 is attached to the battery.

Next, a method of determining full charge (charging completion) will be described. FIG. 3 is a diagram showing charging characteristics and detection timing of the battery charger of the present invention. As shown by a solid line a in the figure, points X and Y near full charge are set, and their current values are Ax and Ay (Ax> Ay), respectively. Assuming that the difference between the degrees of charge at the points X and Y is 1-2%, the time difference between the times Tx and Ty is several minutes from the charging characteristics of the battery 2.

On the other hand, the charging current is attenuated while oscillating due to a contact state, a change in voltage, or the like. However, as described above, the time difference between the times Tx and Ty is sufficiently long, so that the charging control unit 12 can reliably operate at the illustrated detection timing. Where Ay ≤ charging current ≤ Ax
Can be detected. The current set value Ax, Ay is also Ax, setting Ay when the threshold A ₁ is small because the approximate value of the threshold A ₁ of fully charged easily. Further, it can be determined reliably because the charging current ≦ A ₂ without detecting (see FIG dotted b) the full-charge current band (Ax～Ay) If the battery 2 during the charge has been removed.

The determination unit 121 of the charge control unit 12 is a CPU
(Central processing unit), and monitors a detection current detected by the current detection unit 122 and a detection voltage detected by the voltage detection unit 123, performs processing of the battery 2, and performs a charge determination processing. FIG.
5 is a flowchart of the battery charger 1 charge determination process of the present invention. Hereinafter, description will be given with reference to FIG.

First, initialization such as initial setting of necessary variables and turning off the output switch 112 is performed (step ST).
10). The voltage between the charging terminals 14 detected by the voltage detecting unit 123 is monitored, and the voltage between the charging terminals 14 becomes a constant voltage V
₁ (approximately the minimum voltage value of a normal battery that needs charging (if it is lower than this, an abnormal value)), it is determined whether the voltage is higher than an appropriate voltage value for confirming the battery 2). Is determined to have been mounted (step ST1).
1), the charge control unit 12 outputs a signal to the power supply unit 11 and turns on the output switch 112 (step ST12).

The charging control unit 12 reads the charging current flowing through resistor 13 via the current detecting unit 122 determines whether the charging current is lower than the threshold value A ₁ (step ST1
3) If higher, go to step ST20. If the output switch 11 is low, the mounting state may be erroneously detected or the battery 2 may be mounted in a fully charged state.
2 is turned off (step ST14), the voltage between the charging terminals 14 are reaffirmed whether higher than a predetermined voltage V ₁ (step ST15), and repeats steps ST11 regarded if the battery 2 is not attached and lower.

[0022] is turned on again the output switch 112 The higher voltage between the charging terminals 14 than the constant voltages V ₁ in step ST15 (step ST16). Read the charging current,
Determines whether lower or not than the threshold value A ₁ (step ST1
7), lower if determined that the fully charged performed off the output switch 112 displays the like (step ST18), the voltage across the battery 2 is removed charging terminal 14 is waiting to become lower than V ₁ (step ST19), and repeat from step ST11.

[0023] If the charging current is larger than the threshold value A ₁ in step ST17 to continue the charging, the charging current decreases with time as indicated by the solid line a in FIG. 3, the range of the threshold Ax ≦ charging current ≦ threshold Ay (Step ST20), it is determined that the vehicle is passing the full charge current band, and a passage flag is set (Step ST21). Further, the charge current is reduced to <Ay (Step ST22), and the process is repeated from Step ST20.

If the charging current is smaller than Ay, it is determined that the battery is fully charged (charging is completed), the output switch 112 is turned off, and a display or the like is performed (step ST23). If the passing flag is set, that is, the battery passes the full charging current band. (Step ST24), the voltage between charging terminals ≧ V ₁ (step ST2)
If 5), the charging is completed and the process is executed from step ST19. If the passage flag is not set (if not pass through the full-charge current band) and the battery 2 in the case of the charging terminal voltage <V ₁ in step ST25 battery Cha -
Judges that it has been removed from ja 1 and the first step ST11
Repeat from.

As described above, the charging current monitoring type battery charger 1 utilizes the characteristic that the charging current decreases as the charging of the battery 2 progresses.
Since the charging progress and the full charge are detected, a detection switch (or a mounting detection terminal) for detecting the mounting of the battery is not required, so that the number of components is reduced, and the mechanism design and assembling process are facilitated. In addition, the case of the battery charger 1 is reduced in the number of holes for switches (or terminals) and the like, so that the battery charger 1 is simplified in shape, and is more resistant to disturbances due to external factors such as mechanical or static electricity.

[0026]

As described above, according to the present invention, the following excellent effects are expected. (1) In the charge current monitoring type battery charger of the present invention, the mounting of the battery, the progress of the charging, and the full charge are detected by utilizing the characteristic that the charging current decreases as the charging of the battery progresses. A detection switch (or a mounting detection terminal) for detection becomes unnecessary, the number of components is reduced, the mechanism design is facilitated, and the cost can be reduced. (2) In addition, the number of holes for switches (or terminals) is reduced in the case of the battery charger, the shape is simplified, and the failure due to external factors such as mechanical or static electricity is increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a block configuration of a battery charger of the present invention.

FIG. 2 is a flowchart of a charge determination process of a battery charger according to the present invention.

FIG. 3 is a diagram showing charging characteristics and detection timing of the battery charger of the present invention.

FIG. 4 is a diagram showing changes in elapsed time of battery charging and charging current.

FIG. 5 is a diagram showing an example of a block configuration of a conventional battery charger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery charger 11 Power supply unit 111 Constant voltage charging circuit 112 Output switch 12 Charge control unit 121 Judgment unit 122 Current detection unit 123 Voltage detection unit 13 Resistor 14 Charging terminal 2 Battery

Claims (1)

(57) [Claims] 1. A battery controller, comprising: a charging control unit having a charging current detecting unit for detecting a charging current of a battery and a voltage detecting unit for detecting a voltage of the battery; and a charging terminal for connecting the battery, and charging the battery. In the charging device, the charging control unit reads the charging current detected by the charging current detecting unit and the terminal voltage detected by the voltage detecting unit, and determines whether or not the battery is mounted. Full charge determination means for determining whether or not charging has been completed from the value of the charge current, wherein the full charge determination means has a current value near a threshold A ₁ of a charge current when the battery is fully charged. Ax and current value Ay (A
x> Ay), a charging current band of full charge is set, and it is detected that the charging current detected by the charging current detection unit has passed the charging current band, and it is determined that charging is completed. The battery charger has a function of determining that the battery has been removed from the battery charger when the battery has decreased without detecting the passage of the fully charged current band.