JPH04109834A - Charger - Google Patents

Abstract

PURPOSE:To indicate battery voltage or information relevant to a storage battery derived of the battery voltage by detecting the storage battery voltage under released state from charging operation and then operating the number of storage batteries based on thus detected battery voltage. CONSTITUTION:When a storage battery B is switched from charging state to charge stop state, a switch SW is turned OFF and a timer circuit 153 begins measurement of a predetermined time. When the storage battery B voltage is settled upon elapse of the predetermined time, voltage data V of the storage battery B detected through a voltage detecting circuit 14 is read into a microcomputer 15 under a state where a battery pack 11 is separated from the output terminal of a charger. The voltage data V is then converted through an A/D converting circuit 151 into a digital data which is fed to a cell number judging circuit 152 in order to judge the number of cells of the storage battery B. The number N of cell is calculated by dividing the voltage data V by the voltage value V0 per single storage battery, for example.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a charger for electrical equipment such as power tools and shavers.

[Conventional technology]

Conventionally, chargers for electrical equipment such as power tools and shavers have been known to have a display function that indicates when the storage battery is fully charged, but there is no display that indicates the status of the storage battery or battery pack after charging is complete. What is done is unknown.

[Problem to be solved by the invention]

For example, a storage battery may have an internal short circuit due to its lifespan.
If such a defective storage battery is included in a battery pack, even if charging is completed, sufficient power will not be supplied from the storage battery or battery pack to the load such as a motor, and the battery cannot be driven. It turns out you can't do it. However, since conventional chargers do not display the status of the storage battery or battery pack after charging is complete, it is unclear whether the cause of the battery-driven failure is due to deterioration of the storage battery or a failure of the charger. It was difficult to take appropriate countermeasures against defects.

The present invention has been made in view of the above problems, and an object thereof is to provide a charger that can accurately detect the voltage of a storage battery and display the battery voltage or information regarding the storage battery obtained from the battery voltage. do.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a charger for charging one or more storage batteries, which includes a charging canceling means for canceling the charging operation, and a battery voltage detecting means for detecting the voltage of the storage battery in the charging release state. , and display means for displaying the detected battery voltage (Claim 1).

In addition, the present invention provides a charger for charging one or more storage batteries, including a charging canceling means for canceling the charging operation, a battery voltage detecting means for detecting the voltage of the storage battery in a charging canceled state, and a detected battery voltage. The present invention is provided with a calculation means for calculating the number of storage batteries from the above, and a display means for displaying the calculation result (claim 2).

Note that the detected battery voltage may be compared with a plurality of preset threshold values, converted into a representative battery voltage or the number of storage batteries corresponding to the plurality of threshold values, and the converted value may be displayed (as requested). Item 3).

[Effect]

In the invention as set forth in claim 1, the voltage of the storage battery is detected in a charge-released state, and the detection result is displayed on the display means.

Further, in the invention as set forth in claim 2, the voltage of the storage battery is detected in the charge-released state, and the number of storage batteries is calculated from the detection result. Then, the calculation result is displayed on the display means.

Further, in the invention according to claim 3, the detected battery voltage is compared with a plurality of preset threshold values and converted into a representative battery voltage or the number of storage batteries corresponding to the plurality of threshold values,
The converted value will be displayed.

〔Example〕

A charger according to the present invention will be explained using figures.

FIG. 1 is a block diagram of a charger according to the present invention.

In the figure, 1 is an input filter circuit that removes noise components contained in AC voltage e, and 2 is a rectifier and smoothing circuit that includes a rectifier bridge 2a and a smoothing circuit 2b and converts the AC voltage e into a DC voltage.

Further, 3 is a switching circuit, for example, made of a power MO3FET, which performs high-speed switching of the DC voltage generated by the rectifying and smoothing circuit 2, 4 is a driver circuit that drives the switching circuit 3 on and off, and 5 is a switching operation of the switching circuit 3. 6 is an auxiliary power supply circuit that supplies driving power for the driver circuit 4 and the PWM control circuit 5.

Further, 7 is a soft start circuit that instructs switching to gradually increase the charging current from a low level at the start of charging. When attachment of a battery pack 11 (described later) is detected, a pack detection signal is input from a microcomputer 15 (hereinafter referred to as "microcomputer") to be described later to the soft start circuit 7 via a photocoupler 19. Soft start circuit 7
receives the pack detection signal and inputs a soft start control signal to the PWM control circuit 5.
In response to the control signal, the charging current is switched to a value smaller than the predetermined charging current value, and after charging is started, the charging current is gradually increased to the predetermined charging current value.

T is a high frequency transformer that steps down the high frequency AC voltage generated on the primary side by the switching circuit 3 and supplies it to the secondary side. Further, 8 is a rectifying and smoothing circuit that rectifies the AC voltage supplied to the secondary side and is composed of a rectifier circuit 8a and a smoothing circuit 8b, 9 is a current detection circuit that converts the charging current into voltage and detects it, and 10 is the current This is a constant current control circuit that amplifies the detection voltage of the detection circuit 9 and feeds it back to the PWM control circuit 5 via the photocoupler 17.

The PWM control circuit 5 changes the on/off duty of the pulse signal according to the voltage input from the constant current control circuit 1o, and controls the charging current to be constant.

Reference numeral 11 denotes a battery pack that includes a storage battery B to be charged and a temperature sensor Ds for detecting the temperature of the storage battery B, and is connected to the secondary output terminal of the charger via a switch SW. Note that the switch SW is a relay switch that is controlled on and off by the microcomputer 15.

Further, 12 is an amplifier circuit for amplifying the detected voltage of the temperature sensor D8 to a predetermined voltage range corresponding to the temperature detection range;
3 is a pack detection circuit that detects the presence or absence of the battery pack 11;
14 is a voltage detection circuit that detects the voltage of the storage battery B.

In the microcomputer 15, 151 is the voltage detection circuit 1.
152 is a cell number determination circuit that determines the number of cells of storage battery B from the A/D converted voltage data. Further, 153 is a timer circuit for measuring charging time;
54 is an A/D conversion circuit that A/D converts the temperature data of storage battery B input from the amplifier circuit 12, and 155 is an A/D conversion circuit.
Calculate the temperature rise value per unit time of storage battery B from the D-converted temperature data, that is, the temperature rise rate ΔT, and compare the temperature rise rate ΔT with a preset threshold value ΔT to determine the fully charged state. battery temperature rise rate control circuit (hereinafter referred to as Δ
156 is an absolute temperature protection circuit that calculates the absolute temperature of storage battery B from A/D converted temperature data, determines the fully charged state from the absolute temperature, and prevents overcharging. In addition, 157 is a display 16 consisting of an LCD or the like.
This is an LCD driver that drives the .

In the above configuration, the charging state of the storage battery B is determined by the ΔT control circuit 155, and the temperature increase rate ΔT is set to the threshold Δ
When T0 is exceeded, it is determined that the battery is fully charged and an instruction is given to stop charging. Further, the timer circuit 153 and the absolute temperature protection circuit 156 function as a protection circuit to prevent overcharging, and the timer circuit 153 operates when the charging time exceeds a predetermined time.
Absolute temperature protection circuit 156 forcibly instructs to stop charging when the temperature of storage battery B exceeds a predetermined value. These timer circuits 153 and ΔT control circuit 1
55 and the absolute temperature protection circuit 156 instruct to stop charging, the microcomputer 15 outputs a switching signal to the terminal current to the PWM control circuit 5 via the photocoupler 18,
The charging current is switched from a predetermined charging current to a terminal current or zero level.

When the storage battery B is switched from the charging state to the charging stop state, the switch SW is switched to the OFF state and the timer circuit 153 starts counting a predetermined time. Note that this predetermined time is the time from when the battery pack 11 is disconnected from the output terminal of the charger until the voltage of the storage battery B becomes stable. When the predetermined time T is counted, the voltage data V of the storage battery B detected by the voltage detection circuit 14 while the battery pack 11 is disconnected from the output terminal of the charger is read into the microcomputer 15. The voltage take V
is converted into digital data by the A/D conversion circuit 151, and then input to the cell number determination circuit 152, where the number N of cells of storage battery B is determined.

The number of cells N is calculated, for example, by dividing the voltage data V by a preset voltage value vo per storage battery. The number of cells N and the battery voltage data ■ are L
It is output to the display 16 via the CD driver 157 and displayed. Note that either the number of cells N or the battery voltage V may be displayed.

FIG. 3 is a diagram showing the relationship between charging time T and battery voltage V. In the figure, T1 is an arbitrary point in the middle of charging, and T2 is a point in time when the battery is fully charged after the start of charging. When the battery pack 11 is disconnected from the charger to be in a charging release state during charging or when fully charged, the battery voltage decreases slightly as shown by the broken line, and stabilizes after a predetermined time. Therefore, by disconnecting the battery pack 11 from the charger and detecting the voltage after a predetermined period of time, the voltage of the storage battery B can be stably and accurately detected, and the number of cells can also be accurately determined.

In addition, in order to more accurately determine the number of cells, it is preferable to perform voltage detection after the 12th time point when charging is completed.
For example, the number of storage batteries B in the battery pack 11 is an even number (2, 4, etc.).
If the battery consists of 6 batteries, etc.), the battery voltage at time T□ during charging ■1 and the battery voltage after charging completion ■2
Since the voltage difference ΔV (V2 Vl) is small as a voltage value error in determining the number of cells, voltage detection can be performed even at time T1 during charging. When performing voltage detection during charging, the timer circuit 153 measures a predetermined charging time T□ at the same time as charging starts, and when the timing ends, the microcomputer 15 turns off the switch SW, and the timer circuit 153 turns off the switch SW. A predetermined period of time is counted until the voltage stabilizes. Then, after measuring a predetermined time, voltage detection a is performed, and when the voltage detection is completed, the switch sw is turned on again to continue charging.

Further, the number N of cells of the storage battery B may be determined by comparing the voltage data V with a plurality of preset threshold values, and the display of the voltage value only needs to be able to determine the quality of the storage battery B from the displayed voltage. Alternatively, instead of the detected voltage data V itself, a representative voltage value corresponding to the threshold value may be displayed.

Table 1 shows an example of the relationship between the threshold value, the determination result, and the display voltage. For example, voltage data V is 15v
In this case, the threshold value is in the range of 12 to 16V, so storage battery B
The number of cells N is determined to be 10 cells, and the number of cells is "10 cells".
, the voltage value r12vJ is displayed.

In the method of calculating the number of cells and displaying the calculation result and battery data V, the battery data ■ is digit-aligned for display,
The number of cells must be determined from the calculation result with a fraction, which makes the calculation process troublesome. However, with this method, the number of cells N can be determined directly from the voltage data V, and a predetermined number of cells can be determined according to the result of the determination of the number of cells. Since the representative voltage value of is displayed, the cell number determination and data display processing can be performed quickly.

Such calculation processing may be performed by performing calculations or may be performed using a conversion table.

In the above embodiment, when detecting the voltage, the battery pack 11 is disconnected from the output terminal of the charger in order to release the charge, but the charging current is switched to zero level or a minute current, and the battery pack B is may be placed in a charging release state.

FIG. 2 is a block diagram showing an example of this embodiment.

This figure is the same as in FIG. 1 except for the switch SW, and the same members as those in FIG. 1 are given the same numbers.

When the timer circuit 153, ΔT control circuit 155, and absolute temperature protection circuit 156 instruct to stop charging, the microcomputer 15
A switching signal is output from the PWM control circuit 5 to the PWM control circuit 5 via the photocoupler 18, and the charging current is switched to a zero level or a minute current. In addition, when voltage detection is performed during charging, a switching signal is output from the microcomputer 15 to the PWM control circuit 5, the charging current is switched to zero level or a minute current, and voltage detection is performed with the charging released state. When the voltage detection is completed, the charging current is switched to a predetermined current value again to continue charging.

According to the present embodiment described above, for example, when the number of cells in the battery pack 11 is 10, for example, the battery voltage is
When "v" is displayed, it is understood that one of the storage batteries B is defective.

〔Effect of the invention〕

As explained above, according to the present invention, the battery voltage is detected in the charge release state, and the voltage of the storage battery or the number of storage batteries calculated from the detected voltage is displayed. It becomes possible to determine whether the product is good or bad. Thereby, measures such as battery replacement can be appropriately performed.

In addition, the detected battery voltage is compared with multiple preset thresholds, converted to the representative battery voltage or number of storage batteries corresponding to the multiple thresholds, and the converted value is displayed, so the number of cells can be determined. and display processing can be performed quickly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a charger according to the present invention, FIG. 2 is a block diagram showing a second embodiment, and FIG. 3 is a diagram showing the relationship between charging time and battery voltage. 1... Input filter circuit, 2, 8... Rectifier smoothing circuit,
3... Switching circuit, 4... Driver circuit, 5
... PWM control circuit, 6... Auxiliary power supply circuit, 7...
・Soft start circuit, 9... Current detection circuit, 10.
...Constant current control circuit, 11...Battery pack, 12...
・Amplifier circuit, 13...Pack detection circuit, 14...Voltage detection circuit, 15...Microcomputer, 16...Display device (
LCD), 17-19...Photocoupler, 151,1
54... A/D conversion circuit, 151... Cell number determination circuit, 153... Timer circuit, 155... ΔT control circuit, 156... Absolute temperature protection circuit, 157... LC
D driver, B...storage battery, Ds...temperature sensor,
SW...Switch.

Claims (1)

[Claims] In a charger for charging one or more storage batteries,
A charger comprising: a charge canceling means for canceling a charging operation; a battery voltage detecting means for detecting the voltage of a storage battery in a charge canceling state; and a display means for displaying the detected battery voltage. 2. In a charger for charging one or more storage batteries,
Charging canceling means for canceling the charging operation, battery voltage detecting means for detecting the voltage of the storage battery in the charging release state, calculation means for calculating the number of storage batteries from the detected battery voltage, and display means for displaying the calculation result. A charger characterized by comprising: 3. The charger according to claim 1 or 2, further comprising: a setting means in which the representative battery voltage or the number of storage batteries is set corresponding to a plurality of preset threshold values; It is characterized by comprising a comparison means for comparison, and a conversion means for converting the battery voltage detected from the comparison result into a corresponding representative battery voltage or the number of storage batteries, and the converted value is guided to the display means. charger.