JP3894175B2 - Charger - Google Patents

Description

  The present invention relates to a charger for charging a battery.

In a charger for charging a battery, two charging modes having different charging current patterns (charging current magnitude, charging time, and how to change with time of charging current) are prepared and charged. The battery voltage and the battery ambient temperature are detected, and the two charging modes are switched according to whether the detected voltage is lower than the set voltage set according to the battery ambient temperature. Is known (Patent Document 1). This prior art attempts to prevent a reduction in battery life by switching the charging mode depending on the battery temperature.
JP-A-6-225468

  However, on the one hand, users may want to charge quickly, if not considering the impact on battery life, while on the other hand they charge for a long time with a lower charging current, which is more desirable for battery life. There may be no problem. Accordingly, there has been a demand for the appearance of a charger that allows a user to select any mode among a plurality of charging modes as required.

  On the other hand, whenever the charging mode is switched at any time during charging, the charging time being measured is also reset, the pattern corresponding to the new charging mode is repeated from the beginning, and the end of charging is appropriate. It is assumed that inconvenience occurs that it is not performed at the time.

  The present invention has been made in view of the above problems, and provides a charger that allows a user to select one of a plurality of charging modes while appropriately maintaining an end timing of charging. The purpose is to provide.

In order to solve the above problems and achieve the above object, the solution means according to the present invention is a charger for charging a battery, and a power supply means for supplying a charging current to the battery, and a user instruction And a mode switching unit that selects one of a plurality of charging modes having different charging current patterns, and the charging current output by the power source unit is controlled according to the charging mode selected by the mode switching unit. Charging mode control means, wherein the mode switching means allows a user to select a charging mode only during a selection period set at the beginning of a period from the start of charging to the completion of charging. is there.

Preferably, the charge start is powered on simultaneously the charger, the mode switching means, and when the power is turned on of the charger to the origin of the selection period.

  Preferably, the charging current control means controls the power supply means so as to output a charging current even during the selection period.

Preferably, the charging current control means controls the power supply means so that the charging current is zero even during the selection period .

The battery charger of the present invention configured as described above allows the user to select a plurality of charging modes only during a selection period set in the initial period from the start of charging to the completion of charging. Thereby, the user can select one of a plurality of desired charging modes and perform charging while keeping the end timing of charging at an appropriate time. In addition, since the user can select any of a plurality of desired charging modes using a single charger, the user can also reduce the cost of preparing various types of chargers.

(Configuration of charger)
FIG. 1 is a schematic view of an external appearance of a charger according to an embodiment of the present invention and a battery suitable for the charger. The battery to be charged by the charger 3 is used by being mounted on the main body 2 of an electric appliance 100 (an electric tool is illustrated in FIG. 1A) as shown in FIG. In addition, as shown in FIG. 1 (b), the battery pack 1 is configured such that it can be charged by being attached to the charger 3 as it is after being attached and detached. However, the battery to be charged by the charger of the present invention is not limited to the battery pack 1 in general. The battery built in the battery pack 1 is, for example, a nickel cadmium battery or a nickel metal hydride battery. The battery voltage can vary, such as 12V, 18V, 24V.

  The battery pack 1 illustrated in FIG. 1 includes a main body portion 11 that holds a battery, and a connector portion 9 for establishing electrical connection between the electric appliance main body portion 2 and the charger 3. The charger 3 is provided with a connector portion 13 having an opening, and the electrical connection between the battery pack 1 and the charger 3 is established by attaching the connector portion 9 to the connector portion 13. The charger 3 prepares a plurality of charging modes having different charging current patterns.

  The charging modes prepared by the charger 3 include a quick charging mode (high rate charging mode), a low rate charging mode, and a battery activated overcharge mode (so-called refresh mode). The quick charging mode is a mode in which charging is completed in a short time with a large charging current, and the low rate charging mode is a mode in which charging is completed over a long time with a small charging current compared to the rapid charging mode. On the other hand, the battery activated overcharge mode is a mode in which charging is performed with a small charging current and taking a long time as the battery is overcharged, similarly to the low rate charging mode. The battery activation overcharge mode is a mode for activating a battery that has been left unused for a long period of time. In both the quick charge mode and the low rate charge mode, charging is completed as long as the battery is not overcharged. In particular, since the low-rate charging mode performs charging with a small current, it is desirable to use this mode in order to maintain a long battery life when there is no urgency to complete charging in a short time. That is, the low rate charging mode is a charging mode in which battery life is emphasized.

  It is also possible to prepare a plurality of modes having different charging current patterns as the battery activation overcharge mode. For example, as a battery activation overcharge mode, there are two stages: a mode in which overcharge is completed by taking a long time with a small charge current, and a mode in which overcharge is completed in a short time with a larger charge current. You may prepare. Moreover, it is also possible to prepare three or more modes as charging modes that do not cause overcharging. For example, in addition to the quick charge mode and the low rate charge mode, as a charge mode that does not cause overcharge, a third mode may be prepared in which charging is completed in an intermediate time with an intermediate charge current. . It is assumed that the charger 3 illustrated in the drawings of FIG. 1 and the subsequent drawings prepares three charging modes, that is, a quick charging mode, a low rate charging mode, and a battery activated overcharge mode. By operating the changeover switch 5 that is exposed to the outside of the charger 3, the user can arbitrarily select any one of the three charging modes. That is, the charger 3 is configured such that the user can select an arbitrary mode among a plurality of charging modes. In addition, the electric power for operating the charger 3 is supplied through the power line 7 of AC100V, for example.

  More specifically, the battery pack 1 and the charger 3 have an appearance as shown in FIG. In this example, the connector portion 9 of the battery pack 1 has a shape protruding from the main body portion 11 and is disposed so that the electrodes 15, 17, 19, and 21 are exposed on the side surfaces. The connector portion 13 of the charger 3 has a recess into which the connector portion 9 can be inserted, and electrodes 25 and 26 that are electrically connected by contacting the electrodes 15, 17, 19, and 21 on the inner surface thereof. 27, 29, 31 are arranged. For example, the electrodes 17 and 31 are positive charging electrodes, the electrodes 15, 25 and 26 are negative charging electrodes, the electrodes 19 and 29 are electrodes for transmitting a temperature detection signal, and the electrodes 21 and 27 are connected to the battery pack 1 by the battery pack 1. It is an electrode for detecting that it was attached to the head. If the battery pack 1 is not attached to the charger 3, the charger 3 cannot be charged, and if it is attached, it can be charged. Of the electrode 15, the electrode 15 a and the electrode 15 b are connected to the electrodes 25 and 26, respectively. For example, if the battery pack 1 is a battery having a large capacity (the capacity of the battery is expressed in ampere / hour), both the electrodes 15a and 15b are provided, and if the battery pack 1 is a small capacity battery, only the electrode 15a is provided. Provided (including a form in which the electrode 15b is covered with an insulating member). The electrode 26 can detect whether or not the electrode 15b is provided, and thereby the battery capacity of the battery pack 1 can be detected.

  The battery pack 1 and the charger 3 are provided with, for example, slit-shaped air holes 23 and 33 at positions on the surfaces facing each other when they are combined. The charger 3 incorporates a cooling fan (not shown), and the air flow created by the cooling fan is also supplied to the battery (not shown) in the battery pack 1 being charged through the vent holes 23 and 33. It is like that. A display 35 is provided on the surface of the charger 3. The display 35 displays a mode currently selected from the three charging modes. The change-over switch 5 provided on the same upper surface as the display 35 is, for example, a toggle type, and the three charging modes are cyclically switched every time the user presses once.

  FIG. 3 is a block diagram showing the configuration of the charger 3. FIG. 3A shows the hardware configuration of the charger 3, and FIG. 3B shows the configuration of the microcomputer of the charger developed based on the functions. As shown in FIG. 3A, the charger 3 includes a power supply unit 37, a microcomputer (hereinafter abbreviated as “microcomputer” as appropriate) 38, a current detection unit 39, a resistor 40, and a battery voltage detection unit 41. I have. The power supply unit 37 is configured as, for example, an AC-DC converter, and a drive unit 44 that sets a duty ratio of a pulse according to an instruction value output from the microcomputer 38 and an instruction value by switching operation with the set duty ratio. And an output unit 45 for generating a corresponding DC charging current I. The current detector 39 detects the charging current I through a voltage drop of the resistor 40. The battery voltage detection unit 41 detects the voltage of the battery built in the battery pack 1 to be mounted by measuring the voltage between the electrode 27 and the electrode 25.

  The microcomputer 38 includes a CPU (central processing unit), a memory, and the like (not shown), and a program that defines the operation of the CPU is installed in the memory, so that various device elements shown in FIG. To configure. That is, the microcomputer 38 includes a charging current control unit 50, a mode switching unit 51, an overcharge mode data storage unit 52, a low rate charge mode data storage unit 53, a quick charge mode data storage unit 54, and a time measurement unit 57. Yes.

  The mode data storage units 52, 53, and 54 have, for example, a nonvolatile semiconductor memory, and store charging current patterns corresponding to three charging modes. The mode switching unit 51 selects one of the charging current patterns stored in the mode data storage units 52, 53, and 54 according to the operation of the changeover switch 5 and transmits the selected pattern to the charging current control unit 50. The charging current control unit 50 transmits the instruction value of the charging current I to the driving unit 44 based on the charging current pattern transmitted by the mode switching unit 51, the charging current I detected by the current detection unit 39, and the like. The time measuring unit 57 is a device element that measures the time after the start of charging. The charging current control unit 50 generates an instruction value of the charging current I that changes with time according to the charging current pattern transmitted by the mode switching unit 51 while referring to the time measured by the time measuring unit 57.

  The battery temperature detection signal input unit 61 is an apparatus element that receives a battery temperature detection signal when the battery pack 1 has a function of detecting the battery temperature, and includes an electrode 29. The battery capacity detection unit 62 is a device element that detects the battery capacity of the battery built in the battery pack 1, and includes the electrode 26. The mode selection signal input unit 64 is a device element that receives a mode selection signal that conveys the content selected by the mode selection switch when the battery pack 1 includes a mode selection switch that allows the user to select a charging mode. And has an electrode 26.

  The mode switching unit 51 switches the charging mode with reference to a signal from the mode selection signal input unit 64 as described later. In addition, the charging current control unit 50 generates an instruction value for the charging current I while also referring to signals from the battery temperature detection signal 61, the battery capacity detection unit 62, and the battery voltage detection unit 41, as will be described later. In addition, you may comprise the charger 3 so that only a part of function may be implement | achieved by providing only a part among the elements shown in FIG.

(Battery operation)
The charger 3 is configured to set a selection period at the beginning of charging and allow the user to select a charging mode only during this selection period. More specifically, the mode switching unit 51 receives an operation of the changeover switch 5 by the user during a selection period that is a given period in the initial stage of charging, and selects a charging mode according to the operation content. However, after the selection period has elapsed, the mode switching unit 51 does not change the charging mode even if the user operates the changeover switch 5. That is, the charging mode is determined as the selection period elapses, and the charging mode determined until the charging is completed is maintained. Thereby, the charger 3 enables the user to select a desired charging mode, and also eliminates the inconvenience that the charging end time becomes inappropriate as the charging mode is switched.

  The start of the selection period is preferably set at the time when the power supply of the charger 3 is turned on. That is, when the user turns on the power switch (not shown) of the charger 3 or connects the plug of the power supply line 7 to an AC 100V outlet, for example, the time when the reset of the microcomputer 38 is released is set as the starting point of the selection period. The This is because charging is usually started at the same time as the power is turned on, and is therefore suitable as a starting point for the selection period. The selection period is set to about 30 seconds, for example. If the time is shorter than that, the user often loses the opportunity to select a mode. On the other hand, if the time is excessively long, an appropriate charging end time cannot be obtained.

  FIG. 4 is a graph illustrating a pattern of the charging current I output from the charger 3. FIGS. 4A, 4B, and 4C show cases where the user selects the quick charge mode, the low rate charge mode, and the battery activated overcharge mode, respectively. FIG. 4D shows another example of the charging current I pattern when the user selects the quick charging mode. In the example of FIGS. 4A to 4C, the charging current control unit 50 outputs a charging current I having a certain magnitude (for example, 170 mA) in the selection period, and charges by passing the selection period. After the mode is determined, the charging current I according to the pattern corresponding to each charging mode is output. The magnitude of the charging current I during the selection period is, for example, when the battery pack 1 has a control circuit and the battery pack 1 is attached to the charger 3 in a state where the built-in battery is completely discharged. In addition, it may be set for the purpose of supplying a very small current (a current sufficiently smaller than the current necessary for charging the built-in battery) in order to operate the control circuit. For example, by storing the magnitude of the charging current I in the selection period (for example, 170 mA) in a memory (not shown) included in the microcomputer 38, the charging current control unit 50 stores this data in the selection period. By reading, the instruction value of the charging current I can be generated.

  The charging current I pattern in the rapid charging mode (FIG. 4A) and the charging current I pattern in the low rate charging mode (FIG. 4B) are characterized in that the average value of the charging current I is different. It is a difference. That is, in the quick charge mode, the pattern of the charge current I is set so that the average value of the charge current I is larger than that in the low rate charge mode. In the quick charge mode, since the average current is large, charging can be completed in a short time. On the other hand, the low-rate charging mode has an advantage that the battery life can be kept long while it takes a long time to complete charging because the average current is small. Therefore, the user can select a desired mode depending on whether battery life is important or workability is important.

  In the example shown in FIG. 4A, in the quick charging mode, the charging current I is kept relatively small in the initial stage after the selection period ends, then is increased to a large value, and is decreased to a small value near the completion of charging. On the other hand, in the low rate charging mode, the charging current I is maintained at a small value from the end of the selection period until the charging is completed. In these charging modes, the charging current I is kept small in the initial stage because the battery is used immediately after charging and the battery temperature may be high. Further, in the quick charge mode, the charging current I is reduced even in the vicinity of the completion of charging in consideration of the temperature rise of the battery. Both modes thereby suppress battery life degradation as much as possible.

  The timing for switching the charging current I stepwise is determined by the charging current control unit 50 based on, for example, a battery temperature detection signal received by the battery temperature detection signal input unit 61. That is, the charging current control unit 50 reduces the charging current I at the initial stage of charging when the battery temperature is higher than the given threshold temperature, and reduces the charging current I when the battery temperature decreases to near room temperature and falls below the threshold temperature. When the battery charge rises and the completion of charging is approaching and an increase in the battery temperature exceeding the threshold temperature is detected again, the charging current I is lowered. For example, in the quick charge mode, 60 ° C. is set as the threshold temperature, and in the low rate charge mode, 30 ° C. is set. In the low-rate charging mode, it is not normal for the battery temperature to exceed the threshold temperature near the completion of charging. Therefore, as shown in FIG. 4B, the charging current I is normally reduced even near the completion of charging. It will never be done.

  It is also possible to similarly control the charging current I based on the detected value of the battery capacity and / or the battery voltage instead of or together with the temperature. That is, it is possible to perform control to change the charging current I according to the size of the battery capacity or the height of the battery voltage.

  With respect to the charging completion timing, the charging current control unit 50 determines the timing for completing the charging according to the magnitude of the charging current I, for example. Alternatively, it is possible to determine the charging completion time for each charging mode. In this case, the mode data storage units 53 and 54 may store the charging completion time.

  As illustrated in FIG. 4C, in the battery activation overcharge mode, the magnitude of the charge current I is set to a value much smaller than the charge current I in the low rate charge mode. In the example of FIG. 4C, the charging current I after the selection period ends is set to the same magnitude as the charging current I in the selection period and is held at the same magnitude until the charging is completed. In the battery activation overcharge mode, such a minute charging current I is supplied over a long period of time until the battery is overcharged, thereby activating the battery that has been left unused for a long period of time. be able to. An example of the charging time is 30 minutes in the quick charge mode, 1 hour in the low rate charge mode, and 24 hours in the battery activated overcharge mode.

  In the example of FIGS. 4A to 4C, the charging current control unit 50 outputs a minute charging current I in the selection period, but the charging current I is set to zero in the selection period, that is, the charging current in the selection period. It is also possible to refrain from starting I (not shown). Thereby, it is possible to prevent fluctuations in the amount of charge due to the provision of the selection period.

  On the other hand, as illustrated in FIG. 4D, the charging current control unit 50 outputs the charging current I according to the pattern of each charging mode (rapid charging mode in FIG. 4D) even during the selection period. The charger 3 may be configured. In this case, if there is a change in the charging mode within the selection period, the amount of charge will vary slightly, but if the unnecessarily long selection period is not set, the amount of charge will change. Is virtually eliminated. Further, since the start of charging is accelerated, the advantage that the completion of charging is also accelerated is obtained.

  Before the user selects the charging mode in the selection period, the charging current control unit 50 may select a predetermined specific charging mode as an initial setting (default) mode. Further, the charging current control unit 50 may determine the initial setting mode as the charging mode when the user does not select the charging mode in the selection period. In this case, for example, an initial setting mode may be stored in advance in a memory (not shown) included in the microcomputer 38, and the charging current control unit 50 may set the charging mode by reading this data after the power is turned on. .

  As shown in FIG. 5, the battery pack 1 can be provided with a mode selection switch 10 that allows the user to select a charging mode. As described above, the mode selection signal input unit 64 (FIG. 3) transmits the charging mode selected by the mode selection switch 10 to the mode switching unit 51. When there is an input of a charging mode selection signal from the mode selection signal input unit 64, the mode switching unit 51 selects the charging mode according to this signal, for example, in preference to the initial setting mode. Thereby, the user can avoid the annoyance of having to set the charging mode by operating the charger 3 in spite of charging in the same charging mode every time. When the charging mode selection signal is not input from the charger 3, the charging current control unit 50 determines the initial setting mode as the charging mode. The initial setting mode is set to, for example, the safest low-rate charging mode for the built-in battery of the battery pack 1.

It is the schematic of the external appearance of the battery suitable for the charger by the embodiment of this invention, and the said charger. It is a more detailed external view of the charger and battery of FIG. It is a block diagram which shows the structure of the charger of FIG. It is a graph which shows an example of the pattern of the charging current which the charger of FIG. 1 outputs. It is an external view which shows the example which provided the mode selection switch in the battery pack.

Explanation of symbols

  3 Charger 37 Power supply unit 51 Mode switching unit

Claims (4)

A charger for charging a battery,
Power supply means for supplying a charging current to the battery;
Mode switching means for selecting one of a plurality of charging modes having different charging current patterns in accordance with a user instruction;
Charging current control means for controlling the charging current output by the power supply means according to the charging mode selected by the mode switching means,
The mode switching means allows a user to select a charging mode only during a selection period set at an initial stage of a period from the start of charging to the completion of charging. The charging start is simultaneous with turning on the charger ,
The charger according to claim 1, wherein the mode switching unit sets a starting point of the selection period as a time point when the power source of the charger is turned on.   The charger according to claim 1 or 2, wherein the charging current control means controls the power supply means so as to output a charging current even in the selection period. 3. The charger according to claim 1, wherein the charging current control unit controls the power source unit so that the charging current is zero even in the selection period .

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