1. Field of the Invention
The present invention relates to a battery-containing unit and a charging base, the battery-containing unit including a rechargeable battery, and the charging unit charging the battery incorporated in the battery-containing unit.
2. Description of the Related Art
Charging bases have been developed which transmit power from a power supply coil to an induction coil by electromagnetic induction to charge an internal battery (See Japanese Laid-Open Patent Publication No. JP H09-63655 A (1997) and Japanese Utility Model Publication No. JP-U-3011829).
JP H09-63655 A (1997) discloses a structure that includes a charging base having a power supply coil to be energized by a high frequency power supply, and a battery pack having an induction coil inductively connected to the power supply coil. In addition, the battery pack includes a circuit that rectifies an alternating current produced in the induction coil, and supplies the rectified current to a battery to charge the battery. In this structure, when the battery pack is mounted on the charging base, the battery of the battery pack can be charged in a non-contact state.
Also, JP-U-3011829 discloses a structure that includes a battery-containing unit having a battery in its bottom part and a secondary charging adapter under the battery. The secondary charging adapter includes an induction coil and a charging circuit In addition, a structure is also disclosed that includes a charging base having a power supply coil to be inductively connected to the induction coil. When the battery-containing unit is mounted to the charging base to connect the secondary charging adapter to the charging base, power is transmitted from the power supply coil to the induction coil, and the battery of the battery-containing unit will be charged.
In the battery-containing unit and the charging base disclosed in the publications, when the battery-containing unit is placed to the charging base, the battery of the battery-containing unit can be charged without requirement of contacts. This type of structure can charge batteries that are charged at a predetermined power rate until being fully charged (e.g., nickel-hydrogen batteries and nickel-cadmium batteries). However, in the case of batteries that are required to be charged at a charging voltage not exceeding a predetermined voltage to prevent danger, a charging current must be gradually decreased when the batteries approach a fully-charged state. If power is transmitted at a constant rate, an invalid magnetic flux generates an eddy current, and heats a case and the like.
The present invention has been developed for solving the disadvantage. It is an Important object of the present invention to provide a battery-containing and a charging base that reduce unnecessary power transmission in a constant-voltage charging range of a lithium ion battery contained in the battery-containing unit to be able to efficiently charge the lithium ion battery.
To achieve the aforementioned object, a battery-containing and a charging base according to the present invention have the following configuration.
The battery-containing unit includes an energized coil and a lithium ion battery to be charged by electric power produced in the energized coil. The charging base that receives the battery-containing unit, and charges the lithium Ion battery of the battery-containing unit. The battery-containing unit includes a charging circuit that rectifies an alternating current produced in the energized coil to convert the alternating current into a direct current for charging the lithium ion battery, and a transmitter that detects the voltage of the lithium ion battery to be charged and transmits a voltage signal to the charging base. The charging base includes a receiver that receives signals transmitted from the transmitter of the battery-containing unit and detects the voltage signal of the lithium ion battery, and a high frequency power supply that is controlled based on the voltage signal detected by the receiver to provide AC power to the energizing coil whereby charging the lithium ion battery at a voltage not greater than a predetermined voltage. The high frequency power supply of the charging base detects the voltage of the lithium ion battery to be charged through the receiver and the transmitter, and is controlled based on the detected voltage to charge the lithium ion battery so that the voltage of lithium ion battery does not exceed the predetermined voltage.
According to the aforementioned configuration, when the lithium ion battery approaches a fully-charged state, the lithium ion battery can be fully charged so that power is reduced that is provided from the charging base to the battery-containing unit. Accordingly, the lithium ion battery can be fully charged at high efficiency by power provided from the charging base to the battery-containing unit. The reason is that the charging base controls power provided to the battery-containing unit, and charges the lithium ion battery. For this reason, the battery-containing unit does not waste power to control power for charging the lithium ion battery, and it is possible to reduce heat generated by an eddy current in a battery case of the battery-containing unit. Heat generated in the battery-containing unit may adversely affect the lithium ion battery. According to the present invention, since heat generated in the battery-containing unit can be reduced by control of charging power by the charging base side, it is possible to suppress a temperature rise of the lithium ion battery.
In addition, in the battery-containing and the charging base according to the present invention, the transmitter of the battery-containing unit can include a modulating circuit that modulates carrier waves according to the voltage of the lithium ion battery and a transmitting antenna that wirelessly transmits a signal modulated by the modulating circuit by radio waves, and the receiver of the charging base can include a receiving antenna that receives the radio waves wirelessly transmitted from the transmitter and a receiving circuit that demodulates the signal received by the receiving antenna to detect the voltage signal.
According to this configuration, since the voltage signal of the lithium ion battery is transmitted to the charging base by radio waves that are transmitted from the transmitting antenna to the receiving antenna, power can be transmitted from the charging base to the battery-containing unit to charge the lithium ion battery without an influence on power transmission from the energizing coil to the energized coil.
In addition, in the battery-containing and the charging base according to the present invention, the transmitter of the battery-containing unit can transmit the voltage signal of the lithium ion battery to the charging base through the energized coil and the energizing coil.
According to this configuration, the voltage signal of the lithium ion battery can be transmitted from the battery-containing unit to the charging base without antennas. Accordingly, the voltage signal of the lithium ion battery can be stably transmitted from the battery-containing unit to the charging base by a simple circuit structure.
In addition, in the battery-containing and the charging base according to the present invention, the transmitter of the battery-containing unit can include a switching element that controls ON/OFF switching timing based on the voltage signal of the lithium ion battery and is connected to the output side of the energized coil, and the load impedance of the energized coil can be controlled by the ON/OFF switching of the switching element so that the voltage signal of the lithium ion battery is transmitted to the charging base.
According to this configuration, the voltage signal of the lithium ion battery can be stably transmitted to the charging base even by a simple circuit structure in that the switching element is provided in the transmitter to be turned ON/OFF.
In addition, in the battery-containing and the charging base according to the present invention, the transmitter can include a control circuit that controls, based on the voltage signal of the lithium ion battery, a switching-ON period of the switching element or an ON state time width of the switching element.
According to this configuration, since a period or a time width of the switching element represents the voltage signal of the lithium ion battery to be transmitted, the voltage signal of the lithium ion battery can be stably transmitted to the charging base by a simple circuit structure.
In addition, in the battery-containing and the charging base according to the present invention, the battery-containing unit can include an impedance element that is serially connected to the switching element, and a serial connection circuit of the switching element and the impedance element can be connected to the energized coil.
According to this configuration, the voltage signal of the lithium ion battery can be stably transmitted to the charging base by grounding the output side of the energized coil via the impedance element and varying the load impedance of the energized coil at predetermined timing.
In addition, in the battery-containing and the charging base according to the present invention, the impedance element can be a capacitor.
According to this configuration, the voltage signal of the lithium ion battery can be stably transmitted to the charging base by grounding the load of the energized coil via a capacitor that is alternately grounded.
In addition, in the battery-containing and the charging base according to the present invention, the transmitter can include a modulating circuit that modulates carrier waves according to the voltage of the lithium ion battery, the carrier waves that are modulated by the modulating circuit being provided to the energized coil, and the receiver of the charging base can include a receiving circuit that demodulates the carrier waves transmitted from the energized coil to the energizing coil and detects the voltage signal.
According to this configuration, the voltage signal of the lithium ion battery can be stably transmitted to the charging base through radio waves.
In addition, in the battery-containing and the charging base according to the present invention, battery-containing unit can include a detachable battery pack, and the battery pack can include the lithium ion battery, a shield film that shields the lithium ion battery from an AC magnetic field of the energizing coil, the charging circuit for the lithium ion battery, and the transmitter that transmits the voltage signal of the lithium ion battery to the charging base.
According to this configuration, the lithium ion battery of the battery pack can be fully charged so that heat is reduced that is generated in the battery pack. In the case of the battery-containing unit that includes the detachable battery pack, it is more difficult to dissipate heat in the battery pack. The reason is that the battery pack is configured small to be mounted to the battery-containing unit. Since a lithium ion battery and a charging circuit contained in battery-containing units can have a heat dissipation area relatively larger than those contained in a battery pack, as compared with the case of battery packs, heat can be easily dissipated in the lithium ion battery and the charging circuit contained in the battery-containing units. Contrary to this, battery packs are configured very small to be mounted to the battery-containing units. Accordingly, battery packs cannot have a large heat dissipation area. For this reason, it is very important for battery packs to reduce heat generation. According to the aforementioned battery-containing and charging base, the lithium ion battery of the battery pack can be fully charged so that heat is reduced that is generated in the battery pack. In particular, the lithium ion battery can be fully charged with being magnetically shielded from an alternating current magnetic field of the energizing coil by the shield film. In addition, when the lithium ion battery approaches a fully-charged state, power is reduced that is provided from the charging base to the battery-containing unit. Accordingly, the lithium ion battery can be fully charged to reduce heat generated in the shield film, and heat generated in the lithium ion battery and the circuit board that are magnetically shielded by the shield film.
The above and further objects of the present invention as well as the features thereof will become more apparent from the following detailed description to be made in conjunction with the accompanying drawings.
The battery-containing unit 50 (70, 80) includes an energized coil 51 that is inductively connected to an energizing coil 11 of the charging base 10 (30, 40), a charging circuit 52 that rectifies an alternating current produced in the energized coil 51 to convert the alternating current into a direct current for charging the lithium ion battery 60, a detecting circuit 53 that detects the voltage, current and temperature of the lithium ion battery 60 to be charged, and a transmitter 54 (74, 84) that transmits voltage, current signal and temperature signals detected by the detecting circuit 53 to the charging base 10 (30, 40).
Although not illustrated, the charging circuit 52 includes a rectifying circuit that rectifies the alternating current produced in the energized coil 51 and converts the alternating current into a direct current, and a smoothing circuit that is composed of a capacitor for smoothing a fluctuating current flow rectified in the rectifying circuit. The lithium ion battery 60 is fully charged with voltage and current being controlled. However, the charging circuit 52 does not detect the voltage and current of the lithium ion battery 60 to be charged, and does not control the charged state of the lithium ion battery 60 by controlling voltage and current. The charging voltage and the charging current of the lithium ion battery 60 are controlled by a high frequency power supply 12 of the charging base 10 (30, 40).
In order that the high frequency power supply 12 of the charging base 10 (30, 40) may control charging operation for the lithium ion battery 60, the battery-containing unit 50 (70, 80) includes the transmitter 54, (74, 84) that transmits the state of the lithium ion battery 60 to the charging base 10 (30, 40). The transmitter 54 (74, 84) transmits the voltage, current signal and temperature signals detected by the detecting circuit 53 to a receiver 14 (34, 44) of the charging base 10 (30, 40).
The detecting circuit 53 detects the voltage, current and temperature of the lithium ion battery 60. The circuit for detecting the current amplifies the voltage at the both ends of a current detection resistor 57 that is serially connected to the lithium ion battery 60 by means of an amplifier (not shown). The charging current is detected based on the output voltage of the amplifier. In order to detect the temperature of the lithium ion battery 60, a temperature sensor 58 is provided that is thermally coupled to the lithium ion battery 60. The temperature sensor 58 detects the battery temperature by detecting the resistance of an element the resistance of which varies according to temperature (e.g., thermistor). The voltage current, and temperature of the lithium ion battery 60 are converted into digital signals by an A/D converter 59. The A/D converter 59 cyclically converts the voltage, current and temperature into digital signals one after another at a predetermined sampling period, and provides the voltage, current and temperature signals to the transmitter 54 (74, 84).
The charging base 10 (30, 40) includes the receiver 14 (34, 44) that receives signals transmitted from the transmitter 54 (74, 84) of the battery-containing unit 50 (70, 80) and detects the voltage, current and temperature signals of the lithium ion battery 60, and the high frequency power supply 12 that is controlled based on the voltage, current and temperature signals detected by the receiver 14 (34, 44) to provide AC power to the energizing coil 11 whereby charging the lithium ion battery 60 at a voltage not greater than a predetermined voltage.
The high frequency power supply 12 Is controlled through a feedback circuit 17 based on the voltage, current and temperature signals that are detected by the receiver 14. The feedback circuit 17 controls the output of the high frequency power supply 12 so that the lithium ion battery 60 is charged at a constant voltage and a constant current. Accordingly, the feedback circuit 17 controls the output of the high frequency power supply 12 so that the detected voltage of the lithium ion battery 60 does not exceed a preset value. For example, when the voltage of the charged lithium ion battery 60 becomes higher than the preset value, the feedback circuit 17 controls the high frequency power supply 12 so that the output of the high frequency power supply 12 is reduced to reduce the voltage of the lithium ion battery 60. Also, when the voltage of the lithium ion battery 60 becomes lower than the preset value, the feedback circuit 17 controls the high frequency power supply 12 to increase the output of the high frequency power supply 12 so that the voltage of the lithium ion battery 60 is controlled to the preset value. In addition, the feedback circuit 17 also controls the charging current of the lithium ion battery 60. The lithium ion battery 60 is charged at a constant current in the case where the voltage is lower than the preset value. In this case, if the charging current is smaller than a preset value, the feedback circuit 17 controls the high frequency power supply 12 to increase the output of the high frequency power supply 12 so that the charging current is brought to the preset value. Contrary to this, if the charging current is greater than the preset value, the feedback circuit controls the high frequency power supply to reduce the charging current, so that the charging current is brought to the preset value. In addition, the feedback circuit 17 also controls the charging current according to the temperature of the lithium ion battery 60. If the battery temperature becomes higher than a maximum limit temperature or becomes lower than a minimum limit temperature, the charging current Is reduced or the charging current is cut off.
The high frequency power supply 12 is a DC/DC converter that controls duty, though not illustrated, in that a switching element serially connected to a high frequency transformer is turned ON/OFF. Thus, the high frequency power supply 12 can control its output. When the switching element is turned ON at a longer period, in other words, when the duty is greater, the output of the high frequency power supply can be increased, conversely, when the duty is smaller, the output can be reduced.
The following description will describe the transmitter of the battery-containing unit and the receiver of the charging base according to the first to third embodiments with reference to
The transmitter 54 of said battery-containing unit 50 includes a modulating circuit 55 that modulates carrier waves according to the voltage, current and temperature signals, and a transmitting antenna 56 that wirelessly transmits signals modulated by the modulating circuit 55 by radio waves. The transmitter 54 modulates the carrier waves by means of the modulating circuit 55, and wirelessly transmits the carrier waves from the transmitting antenna 56 by radio waves. The transmitter 54 wirelessly transmits the carrier waves according to the voltage, current and temperature signals cyclically provided one after another from the detecting circuit 53 from the transmitting antenna 56 by radio waves. For example, the frequency of the carrier waves can be several MHz to several GHz. The transmitting antenna 56 of the transmitter 54 is located in proximity to the energized coil 51,
The receiver 14 of the charging base 10 shown in
The battery-containing unit 50 and the charging base 10 shown in
The battery-containing units 70 and 80 and the charging bases 30 and 40 shown in
The battery-containing unit 70 and the charging base 30 shown in
The receiver 30 includes a receiving circuit 35 that demodulates the carrier waves transmitted from the energized coil 51 to the energizing coil 11, and detects the voltage, current and temperature signals. High frequency output produced in the energizing coil 11 is provided to the receiving circuit 35 of the receiver 34 via a coupling capacitor 36. Although not illustrated, the receiving circuit 35 includes a tuning circuit that selectively receives the carrier waves from the provided signals, and a demodulating circuit that demodulates the carrier waves selectively received by the tuning circuit and detects the voltage, current and temperature signals. The receiving circuit 35 selectively detects the carrier waves by means of the tuning circuit, and demodulates the detected carrier waves by means of the demodulating circuit to detect the voltage, current, and temperature of the lithium ion battery 60. The detected voltage, current and temperature signals are provided to the feedback circuit 17. The feedback circuit 17 controls the high frequency power supply 12 based on the provided signals, and control the charging voltage and current of the lithium ion battery 60 to charge the lithium ion battery 60 at a constant voltage and a constant current.
The transmitter 84 of the battery-containing unit 80 shown in
In the case of
As shown in
The receiver 44 of the charging base 40 detects the change of the load impedance of the energized coil 51 based on waveform shaping. When the switching element 86 is turned ON/OFF, the waveform of a high frequency signal changes that is produced in the energizing coil 11. The receiver 44 shapes the waveform in the energizing coil 11 by means of a waveform shaping circuit 45, and detects the variation of the impedance of the energized coil 51. The waveform shaping circuit 45 provides a trigger signal that is synchronized with switching-ON timing of the switching element 86 of the transmitter 84. The receiver 44 detects the voltage, current and temperature of the lithium ion battery 60 based on the periods (t1, t2, t3) of the trigger signals. The feedback circuit 17 is provided with the voltage, current and temperature signals of the lithium ion battery 60 that are detected by the receiver 44. The feedback circuit 17 controls the high frequency power supply 12 based on the provided voltage, current and temperature signals to charge the lithium ion battery 60 at a constant voltage and a constant current.
A battery pack 61 is detachably attached to a battery accommodating portion 62 of the battery-containing unit 50 shown In
As shown in
However, the battery-containing unit may not have the detachable battery pack. In this case, a non-detachable, rechargeable lithium ion battery can be contained In the battery-containing unit, and the charging circuit for the lithium Ion battery, the detecting circuit and the transmitter can be also contained in the battery-containing unit. Alternatively, the battery-containing unit may have a detachable battery pack that includes only the lithium ion battery, and the charging circuit for the lithium ion battery, the detecting circuit and the transmitter may be non-detachably configured and contained in the battery-containing unit. In the case where the battery-containing unit itself includes the contained charging circuit, and the detachable battery pack of the battery-containing unit includes the lithium ion battery, the charging circuit and the battery pack are connected to each other via their contacts so that the lithium ion battery is charged with power produced in the energized coil.
The battery pack 61 shown in
The lithium ion battery 60 shown in
Although not illustrated, the circuit board 64 includes on-board electronic components that realize the detecting circuit for detecting the voltage, current and temperature of the lithium ion battery 60, and on-board electronic components that realize the transmitter for transmitting the voltage, current and temperature of the lithium ion battery 60 detected by the detecting circuit to the charging base. Although not illustrated, the circuit board 64 includes an on-board protection circuit for the lithium Ion battery 60. The protection circuit is a circuit that protects the lithium ion battery 60 from an over-current, or a circuit that prevents the lithium ion battery 60 from being over-charged and over-discharged. In the battery pack 61 shown
The energized coil 51 is a flat coil composed of wire lines that are spirally coiled on a plane. The flat coil of the energized coil 51 is a coreless coil. The energized coil 51 of the flat coil is arranged and secured above the first flat surface 60a of the thin battery to interpose the shield film 68 between them. When the battery pack 61 is placed to the battery-containing unit 50, the energized coil 51 is located inside the detachable lid 63 as a back surface plate, and is arranged in proximity to and in parallel to the back surface plate. The energized coil 51 is composed of a plurality of insulated metal lines that are spirally coiled in parallel to the first flat surface 60a of the lithium ion battery 60 of the thin battery to compose the coreless, flat coil.
In the case of the battery-containing unit that charges the lithium ion battery 60 by magnetic induction of the energized coil 51, if an eddy current caused by the magnetic induction flows in an exterior can of the lithium ion battery 60, adverse effects such as heat generation in the exterior can may arise. In order to prevent such adverse effects, the shield film 68 is arranged between the energized coil 51 and the first flat surface 60a of the lithium ion battery 60.
The shield film 68 magnetically shields the lithium ion battery 60 from magnetic flux from the energizing coil 11 to prevent adverse effects on the lithium ion battery 60. The shield film 68 is formed in a sheet shape, and is formed of a high-permeability material such as amorphous metal to shield the magnetic flux from the energizing coil 11. The sheet-shaped shield film 68 is laminated on the first flat surface 60a of the lithium ion battery 60 of the thin battery, and the energized coil 51 is arranged on the shield film 68. The shield film 68 has a shape that covers the first flat surface 60a, in other words, a rectangular shape same as the first flat surface 60a. The shield film 68 covers the entire surface of or the substantially entire surface of the first flat surface 60a.
According to the configuration in that the energized coil 51 is thus arranged above the lithium ion battery 60 to interpose the shield film 68 between them, it is possible to effectively prevent effects caused by magnetic flux, such as adverse effects of heat generation caused by an eddy current produced in the exterior can of the lithium ion battery 60 and the like. In addition to this, since the lithium ion battery 60 does not affect the magnetic flux flowing from the energizing coil 11, there is a feature in that power can be transmitted from the energizing coil 11 to the energized coil 51 at higher efficiency.
The spacer 66 is formed in a sheet shape or a plate shape to be laminated onto the first flat surface 60a, and has a rectangular shape same as the first flat surface 60a. The spacer 66 shown in
The plastic film 67 is a flexible insulating sheet or label formed of plastic. The plastic film 67 is adhered onto the lithium ion battery 60 and the cover case 65 by an adhesive or an adhesive layer. The plastic film 67 is adhered on the first and second flat surfaces 60a and 60b, and the both side surfaces of the lithium ion battery 60 of the thin battery. The aforementioned battery pack is assembled by covering the outer peripheral surfaces by the plastic film 67. It should be appreciated that the battery pack may include a frame case that covers the outer periphery of the battery. This type of frame case can be formed of plastic to be integrally formed with the whole battery.
The charging base 10 (30, 40) charges the lithium ion battery 60 of the battery-containing unit 50 (70, 80) as follows:
In the charging base 10 (30, 40) that thus charges the lithium ion battery 60 of the battery-containing unit 50 (70, 80), the energizing coil 11 connected to the high frequency power supply 12 is contained in the case 20. The energizing coil 11 is located under the upper plate 21 of the case 20 to be moved along the upper plate 21. The efficiency of power transmission from the energizing coil 11 to the energized coil 51 can be improved by reduction of the interval between the energizing coil 11 and the energized coil 51. Preferably, the interval between the energizing coil 11 and the energized coil 51 is not more than 7 mm when the energizing coil 11 is located at the position close to the energized coil 51. To achieve this, the energizing coil 11 is located under the upper plate 21 as closer as possible to the upper plate 21. In order that the energizing coil 11 may be moved to approach the energized coil 51 of the battery-containing unit 50 placed on the upper plate 21, the energizing coil 11 is configured to move along the lower surface of the upper plate 21.
The case 20 that accommodates the energizing coil 11 has the flat upper surface plate 21 on its upper side that bears the battery-containing unit 50 (70, 80). In the illustrated charging base 10 (30, 40), the upper plate 21 has a flat shape that is horizontally oriented as a whole. The upper plate 21 has a size capable of bearing various types of battery-containing units 50 (70, 80) with different sizes and exterior shapes on its upper surface (e.g., a rectangular shape with a side of 5 cm to 30 cm, or an oval shape with a diameter of 5 cm to 30 cm). In the case where the charging base has a large upper plate, in other words, has a size capable of bearing a plurality of battery-containing units, a plurality of battery-containing units can be placed together on the charging base so that the contained batteries can be charged one after another. The upper plate may have a peripheral wall or the like around its periphery. In this case, the battery-containing unit can be placed inside the peripheral wall so that the contained battery can be charged.
The energizing coil 11 is spirally coiled on a plane parallel to the upper plate 21, and produces AC magnetic flux upward of the upper plate 21. The energizing coil 11 produces the AC magnetic flux perpendicular to the upper plate 21 upward of the upper plate 21. The energizing coil 11 is provided with AC power from the high frequency power supply 12 to produce the AC magnetic flux upward of the upper plate 21. The inductance of the energizing coil 11 can be increased by coiling a wire line around a core 28 formed of a magnetic material. The core 28 is formed of a high-permeability material such as ferrite, and is a pot core that opens upward. The pot core 28 has a pillar portion 28A and a cylindrical wall portion 28B that are coupled to the bottom of the core 28. The pillar portion 28A is arranged at the center of the spirally-wound energizing coil 11. The cylindrical wall portion 28B is arranged the outer periphery of the core 28. The energizing coil 11 with the core 28 concentrates the magnetic flux into a particular part, and can efficiently transmit power to the energized coil 51. It should be appreciated that the energizing coil does not necessarily include the core but can be a coreless coil. Since a coreless coil is light, it is possible to simplify the actuating mechanism that moves the coil under the interior surface of the upper plate. The energizing coil 11 has an outer diameter substantially equal to the energized coil 51 in order to efficiently transmit power to the energized coil 51.
The high frequency power supply 12 is connected to the energizing coil 11 via a flexible lead line 29. The reason is that the energizing coil 11 is moved to approach the energized coil 51 of the battery-containing unit 50 (70, 80) that is placed on the upper plate 21. Although not illustrated, the high frequency power supply 12 includes a self-excited oscillating circuit, and a power amplifier that amplifies power of an alternating current provided from the oscillating circuit. The self-excited oscillating circuit uses the energizing coil 11 as an oscillating coil. Accordingly, the oscillation frequency of the oscillating circuit varies according to the inductance of the energizing coil 11. The inductance of the energizing coil 11 varies according to the relative position between the energizing coil 11 and the energized coil 51. The reason is that the mutual inductance of the energizing coil 11 and the energized coil 51 varies according to the relative position between the energizing coil 11 and the energized coil 51. Accordingly, in the case of the self-excited oscillating circuit that uses the energizing coil 11 as the oscillating coil, the oscillation frequency varies as the high frequency power supply 12 approaches the energized coil 51. For this reason, the self-excited oscillating circuit can detect the relative position between the energizing coil 11 and the energized coil 51 based on the variation of the oscillation frequency, and can serve as the position detecting controller 18.
The energizing coil 11 is moved by the actuating mechanism 13 to approach the energized coil 51. The actuating mechanism 13 shown in
The illustrated actuating mechanism 13 includes a guide rod 26 in parallel to the Y-directional threaded rod 23B in order to move the energizing coil 11 in the Y-direction in a horizontal orientation. The both ends of the guide rod 26 are coupled to the pair of X-directional nut members 24A so that the guide rod moves together with the pair of X-directional nut members 24A. The guide rod 26 penetrates a guide portion 27 coupled to the energizing coil 11 so that the energizing coil 11 can be moved in the Y-direction along the guide rod 26. That is, the energizing coil 11 is moved in the Y-direction in the horizontal orientation through the Y-directional nut member 24B and the guide portion 27 that are moved along the Y-directional threaded rod 23B and the guide rod 26 arranged in parallel to each other.
In the actuating mechanism 13, when the X-directional servo motor 22A rotates the X-directional threaded rod 23A, the pair of X-directional nut members 24A are moved along the X-directional threaded rods 23A so that the Y-directional threaded rod 23B and the guide rod 26 are moved in the X-direction. When the Y-directional servo motor 22B rotates the Y-directional threaded rod 23B, the Y-directional nut member 24B is moved along the Y-directional threaded rod 23B so that the energizing coil 11 is moved in the Y-direction. The guide portion 27 coupled to the energizing coil 11 is moved along the guide rod 26 to move the energizing coil 11 in the Y-direction in the horizontal orientation. Thus, the position detecting controller 18 controls the rotation of the X-axis servo motor 22A and the Y-axis servo motor 22B so that the energizing coil 11 can be moved in the X and Y directions. However, the actuating mechanism of the charging base is not limited to the aforementioned mechanism. The reason is that the actuating mechanism can employ any mechanisms that can move the energizing coil in the X and Y directions.
Also, the actuating mechanism of the charging base is not limited to the mechanism that moves the energizing coil in the X and Y directions. The reason is that the charging base can be configured to be provided with a straight guide wall on the upper plate to bear the battery-containing unit along the guide wall, and can be configured to linearly move the energizing coil along the guide wall. In this case, although not illustrated, the thus-configured charging base can include an actuating mechanism that moves the energizing coil in one direction, for example, the X direction, to lineally move the energizing coil along the guide wall.
The position detecting controller 18 detects the position of the battery-containing unit 50 (70, 80) placed on the upper plate 21. The position detecting controller 18 shown in
As shown in
The position detecting coils 90 are a plurality of rows of coils. The plurality of position detecting coils 90 are secured on the interior surface of the upper plate 21, and are spaced away from each other at a predetermined interval. The position detecting coils 90 are a plurality of X-directional and Y-directional detecting coils 90A and 90B that detect the X-directional and Y-directional positions of the energized coil 51, respectively. Each of the X-directional detecting coils 90A has a loop shape that elongates in the Y direction. A plurality of X-directional detecting coils 90A are secured on the interior surface of the upper plate 21, and are spaced away form each other at a predetermined interval. The interval (d) between the adjacent X-directional detecting coils 90A is smaller than the outer diameter (D) of the energized coil 51. The interval (d) between the X-directional detecting coils 90A is preferably ¼ to 1 time as long as the outer diameter (D) of the energized coil 51. Reduction of the interval (d) allows the X-directional detecting coil 90A to accurately detect the X-directional position of the energized coil 51. Each of the Y-directional detecting coils 90B has a loop shape that elongates in the X direction. A plurality of Y-directional detecting coils 90B are secured on the interior surface of the upper plate 21, and are spaced away form each other at a predetermined interval. Similar to the X-directional detecting coil 90A, the interval (d) between the adjacent Y-directional detecting coils 90B is smaller than the outer diameter (D) of the energized coil 51. The interval (d) between the Y-directional detecting coils 90B is preferably ¼ to 1 time as long as the outer diameter (D) of the energized coil 51. Also, reduction of the interval (d) allows the Y-directional detecting coil 90B to accurately detect the Y-directional position of the energized coil 51.
The pulse power supply 91 provides the pulse signals to the position detecting coils 90 at predetermined timing. The position detecting coil 90 that receives the pulse signal excites the energized coil 51 in proximity to the position detecting coil 90 with the pulse signal. The excited energized coil 51 provides the echo signal to the position detecting coils 90 with energy of a current that flows in the energized coil 51. Accordingly, after the energized coil 51 receives the pulse signal, the echo signal from the energized coil 51 is produced in the position detecting coil 90 that Is located close to the energized coil 51 with a predetermined delay as shown in
In the position detecting controller 18 shown in
The position detecting controller 18 shown in
The receiving circuit 92 is an amplifier that amplifies and then provides the echo signals that are provided from the position detecting coils 90. The receiving circuit 92 provides the pulse signals and the echo signals. The determination circuit 93 determines whether the energized coil 51 is placed close to one of the position detecting coils 90 based on the pulse signals and the echo signals provided from the receiving circuit 92. The determination circuit 93 includes an A/D converter 96 that converts the signals provided from the receiving circuit 92 into digital signals. The echo signal is detected based on calculation of the digital signal provided from the A/D converter 96. The determination circuit 93 detects a signal that is provided after a given delay time from the pulse signal as an echo signal, and determines whether the energized coil 51 is located close to one of the position detecting coils 90 based on the level of the echo signal.
The determination circuit 93 controls the switching circuit 94 to connect the plurality of X-directional detecting coils 90A to the receiving circuit 92 one after another to detect the X-directional position of the energized coil 51. Every when connecting one of the X-directional detecting coils 90A to the receiving circuit 92, the determination circuit 93 provides the pulse signal to the one of the X-directional detecting coils 90A that is connected to the determination circuit 93. The determination circuit 93 determines whether the energized coil 51 is located close to this X-directional detecting coil 90A based on whether the echo signal is detected after the given delay time from the pulse signal. The determination circuit 93 thus connects all the X-directional detecting coils 90A to the receiving circuit 92 to detect whether the energized coil 51 is located close to any of the X-directional detecting coils 90A. If the energized coil 51 is located close to any of X-directional detecting coils 90A, the echo signal will be detected when this X-directional detecting coil 90A is connected to the receiving circuit 92. Accordingly, the determination circuit 93 can detect the X-directional position of the energized coil 51 by means of the X-directional detecting coils 90A that can detect the echo signals. In the case where the energized coil 51 straddles two or more of the X-directional detecting coils 90A, the echo signals will be detected from the two or more of the X-directional detecting coils 90A. In this case, the determination circuit 93 determines that the energized coil is located close to one of the X-directional detecting coils 90A that detects the strongest echo signal, that is, an echo signal with the highest level. The determination circuit 93 similarly controls the Y-directional detecting coil 90B to detect the Y-directional position of the energized coil 51.
The determination circuit 93 controls the actuating mechanism 13 based on the X and Y directional positions to move the energizing coil 11 to the position close to the energized coil 51. The determination circuit 93 controls the X-directional servo motor 22A of the actuating mechanism 13 to move the energizing coil 11 to the X-directional position of the energized coil 51. Also, the determination circuit controls the Y-directional servo motor 22B of the actuating mechanism 13 to move the energizing coil 11 to the Y-directional position of the energized coil 51.
Thus, the first position detecting control portion 18A moves the energizing coil 11 to the position close to the energized coil 51. After moving the energizing coil 11 to a position close to the energized coil 51 by the first position detecting control portion 18A, the charging base can transmit power from the energizing coil 11 to the energized coil 51 to charge the lithium ion battery 60. Alternatively, after accurately controlling the position of the energizing coil 11 to move the energizing coil 11 to the position close to the energized coil 51, the charging base can charge the lithium ion battery 60. The energizing coil 11 is more accurately moved to the position close to the energized coil 51 by the second position detecting control portion 18B.
The second position detecting control portion 18B accurately detects the position of the energizing coil 11 by means of the high frequency power supply 12 as a self-excited oscillating circuit based on the oscillation frequency of the self-excited oscillating circuit, and the actuating mechanism 13 is controlled. The second position detecting control portion 18B controls the X-directional servo motor 22A and the Y-directional servo motor 22B of the actuating mechanism 13 to move the energizing coil 11 in the X and Y directions, and detects the oscillation frequency of the high frequency power supply 12.
After roughly detecting the position of the energized coil 51 by means of the first position detecting control portion 18A, the aforementioned charging base finely adjusts the position of the energized coil 51 by means of the second position detecting controlling portion 18B so that the energizing coil 11 is located close to the energized coil 51. On the other hand, the following position detecting controller 38 shown In
As shown in
The position detecting controller 38 calculates the position of the energized coil 51 based on the levels of the echo signals produced in the position detecting coils 90 as follows. The position detecting coils 90 shown in
The memory circuit 99 of the determination circuit 73 stores the levels of the echo signals produced in the X-directional position detecting coils 90A in relation to the X-directional position of the energized coil 51. If the energized coil 51 is placed, the echo signal will be produced in any of the X-directional position detecting coils 90A. Thus, the determination circuit 98 detects that the energized coil 51 is placed, in other words, that the battery-containing unit is placed on the charging base based on the echo signal produced in the X-directional position detecting coil 90A. In addition, the X-directional position of the energized coil 51 can be determined based on comparison of the level of the echo signal produced in one of the X-directional position detecting coils 90A with the levels stored in the memory circuit 99. The memory circuit of the determination circuit can store a function that determines the X-directional position of the energized coil based on the level ratio of the echo signals produced in the adjacent X-directional position detecting coils to determine the position of the energized coil based on the function. The function can be obtained by detecting, when the energized coil is moved between two X-directional position detecting coils, the level ratios of the echo signals produced in the X-directional position detecting coils. The determination circuit 98 detects the level ratio of the echo signals produced in two X-directional position detecting coils 90A, and can calculate and detect the X-directional position of the energized coil 51 between the two X-directional position detecting coils 90A by substituting the detected level ratio in the function.
As stated above, the determination circuit 98 detects the X-directional position of the energized coil 51 based on the echo signals produced in the X-directional position detecting coils 90A. The Y-directional position of the energized coil 51 can be detected based on the echo signals produced in the Y-directional position detecting coils 90B similarly to the X-directional position.
When the determination circuit 98 detects the X-directional and Y-directional positions of the energized coil 51, the position detecting controller 38 moves the energizing coil 11 to the position of the energized coil 51 based on the position signals from this determination circuit 98.
When the echo signal with the aforementioned waveform is detected, the determination circuit 98 of the charging base can recognize and determines that the energized coil 51 of the battery-containing unit 50 (70, 80) is placed on the charging base. If a waveform different from the waveform of the echo signal is detected and determined, it is determined that something other than the energized coil 51 of the battery-containing unit 50 (70, 80), for example, a metal foreign object is placed on the charging base, and power supply can be stopped. Also, in the case where the waveform of the echo signal is not detected and determined. It is determined that the energized coil 51 of the battery-containing unit 50 (70, 80) is not placed on the charging base, and power is supplied.
The charging base 10, (30, 40) controls the actuating mechanism 13 by means of the position detecting controller 18 (38) to positions the energizing coil 11 at the position close to the energized coil 51, and then supplies AC power to the energizing coil 11 by means of the high frequency power supply 12. The AC power of the energizing coil 11 is transmitted to the energized coil 51, and is used to charge the lithium ion battery 60. The battery-containing unit 50 (70, 80) detects the voltage, current and temperature of the lithium ion battery 60 to be charged by means of the detecting circuit 53, and transmits the voltage, current and temperature detected by the detecting circuit 53 as the voltage, current and temperature signals from the transmitter 54 (74, 84) to the charging base 10 (30, 40). The charging base 10 (30, 40) receives the voltage, current and temperature signals transmitted from the transmitter 54 (74, 84) by means of the receiver 14 (34, 44), and controls the high frequency power supply 12 through the feedback circuit 17. The feedback circuit 17 controls the output of the high frequency power supply 12 so that the lithium ion battery 60 is charged at a constant voltage and a constant current.
When the lithium ion battery 60 is fully charged, the detecting circuit 53 determines that the lithium ion battery 60 is fully charged, and the battery-containing unit 50 (70, 80) transmits a full charge signal to the charging base 10 (30, 40). For example, when a charging current of the lithium ion battery 60 becomes lower than a preset current, the detecting circuit 53 determines that the lithium ion battery 60 is fully charged, and provides the full charge signal. The full charge signal is transmitted from the transmitter 54 (74, 84) of the battery-containing unit 50 (70, 80) to the charging base 10 (30, 40). When receiving the full charge signal transmitted from the transmitter 54 (74, 84) by means of the receiver 14 (34, 44), the charging base 10 (30, 40) controls the high frequency power supply 12 through the feedback circuit 17 to stop power transmission by the energizing coil 11 so that the charging operation of the lithium ion battery 60 is completed.
The transmitter 54 of the battery-containing unit 50 shown in
Also, the fully-charged state of the lithium ion battery charged may be detected not by the detecting circuit of the battery-containing unit but by the charging base. In this case, the charging base detects the charging current of the charged lithium ion battery based on the current signal transmitted from the battery-containing unit. When the current value becomes smaller than a preset current, the charging base determines that the lithium ion battery is fully charged, and controls the high frequency power supply so that power is not transmitted from the energizing coil.
In the case of the charging base 10 where a plurality of battery-containing units 50 can be placed on the upper plate 21, the charging base 10 can charge the lithium ion batteries 60 of the plurality of battery-containing units 50 in turn to the fully-charged state. The charging base 10 detects the position of the energized coil 51 of a first battery-containing unit 50, and moves the energizing coil 11 to a position close to this energized coil 51 to charge the lithium ion battery 60 of this battery-containing unit 50 to the fully-charged state. When the lithium ion battery 60 of this battery-containing unit 50 is fully charged, the full charge signal is received. The position detecting controller 18 then detects the position of the energized coil 51 of a second battery-containing unit 50 that is placed on a position other than the fully-charged battery-containing unit 50, and controls the actuating mechanism 13 to move the energizing coil 11 to a position close to the energized coil 51 of the second battery-containing unit 50. After that, power is transmitted to the lithium ion battery 60 of the second battery-containing unit 50, and this lithium ion battery 60 will be fully charged. Also, when the lithium ion battery 60 of the second battery-containing unit 50 is fully charged, the full charge signal is received from the second battery-containing unit 50. After that, the position detecting controller 18 additionally detects the energized coil 51 of a third battery-containing unit 50, and controls the actuating mechanism 13 to move the energizing coil 11 to a position close to the energized coil 51 of the third battery-containing unit 50. The lithium ion battery 60 of the third battery-containing unit 50 will be then fully charged. As stated above, in the case where a plurality of battery-containing units 50 are placed on the upper plate 21, the lithium ion batteries 60 of the battery-containing units 50 are charged one after another to the fully-charged state. This charging base 10 stores the position of the battery-containing unit 50 that have been fully charged, and does not charge the lithium ion battery 60 of the fully-charged battery-containing unit 50 again. If determining that the lithium ion batteries 60 of all the battery-containing units 50 placed on the upper plate 21 are fully charged, the charging base 10 stops operation of the high frequency power supply 12 to stop charging operation of the lithium Ion battery 60.
The thus-configured charging base 10 (30, 40) detects the position of the battery-containing unit 50 (70, 80) placed on the upper surface of the case 20 by means of the position detecting controller 18, and controls the actuating mechanism 13 to move the energizing coil 11 to the position close to the energized coil 51 of the battery-containing unit 50 (70, 80). Accordingly, there is a feature in that power can be efficiently transmitted from the energizing coil 11 to the energized coil 51, and the lithium ion battery 60 can be efficiently charged that is contained in the battery-containing unit 50 (70, 80). In particular, in the case where the position detecting controller 18 detects the position of the energized coil 51 of the battery-containing unit 50 (70, 80), and controls the actuating mechanism 13 to move the energizing coil 11 to the position close to the energized coil 51, there is a feature in that information including the voltage and the like of the lithium ion battery 60 detected by the detecting circuit 53 can be reliably transmitted from the battery-containing unit 50 (70, 80) to the charging base 10 (30,40). The reasons are that, in the case where information is transmitted through the transmitting antenna 56 and the receiving antenna 16 as shown in
However, the charger of the present invention is not limited to the aforementioned configuration. Although not illustrated, the charger may include a mount portion to which the battery-containing unit is detachably attached at a predetermined position. In this charger, the energizing coil is arranged at the position opposed to the energized coil so that power can be transmitted to the energized coil of the battery-containing unit mounted to the mount portion. After the battery-containing unit is mounted to the mount portion so that the induction coil is arranged at a predetermined position in the charging base, in other words, the energized coil and the energizing coil are located close to each other, the charging base reliably transmits power and efficiently charges the lithium ion battery contained in the battery-containing unit. In addition, the information including the voltage and the like of the lithium ion battery detected by the detecting circuit of the battery-containing unit can be reliably transmitted from the battery-containing unit to the charging base.
It should be apparent to those with an ordinary skill in the art that while various preferred embodiments of the Invention have been shown and described, it is contemplated that the invention is not limited to the particular embodiments disclosed, which are deemed to be merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention, and which are suitable for all modifications and changes falling within the scope of the invention as defined in the appended claims. The present application is based on Application No. 2008-124105 filed in Japan on May 10, 2008, the content of which is contained herein by reference.
Number | Date | Country | Kind |
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2008-124105 | May 2008 | JP | national |