JPH1140208A - Charging table and pack battery set on the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve a charging fault caused by a fault in the contact, and to charge a secondary battery under ideal condition, safely, and without lowering battery performance by charging the secondary battery with no contact, without providing a pack battery with a terminal for charging. SOLUTION: A charging table 1 and a pack battery set on the charging table 1 are constructed, so that the charging table 1 contains a primary coil 13 excited by an alternating current, and the pack battery 2 contains a secondary coil 14 electromagnetically connected with the primary coil 13 and a control circuit. A secondary battery 11, contained in the pack battery is charged with alternating power, which is induced to the secondary coil 14 and controlled by the control circuit contained in the pack battery. Also, the pack battery contains the secondary battery 11, an exterior can 12 of which is made of iron or iron alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging stand and a battery pack charged by the charging stand. In particular, the present invention allows the primary coil and the secondary coil to approach each other without passing through the charging contact, to transfer power by electromagnetic induction, and to transfer charging power from the charging stand to the battery pack in a contactless manner. The present invention relates to a charging stand for charging a secondary battery and a battery pack mounted on the charging stand.

[0002]

2. Description of the Related Art A battery pack has a charging terminal exposed at the bottom, for example, so that it can be charged on a charging stand while being attached to a portable electric device. Since the bottom charging terminal cannot be connected to a portable electric device, a discharging terminal is provided separately. The discharge terminal is a terminal for connecting the battery pack to the portable electric device, and can be disposed inside the portable battery device with the battery pack attached. However, since the charging terminal needs to be mounted on the charging stand and brought into contact with the power terminal of the charging stand, it is necessary to arrange the charging terminal at a position that is exposed to the outside. In particular, the battery pack to be attached to the portable electric device and attached to the charging stand needs to be disposed at a position where it is exposed to the outside even when attached to the portable electric device.
For this reason, the charging terminal of the battery pack is exposed to an environment that is extremely dirty, and has a drawback that contact failure easily occurs when the charging terminal is mounted on the charging stand.

In particular, in order to charge a battery pack in a more normal state, many battery terminals have a large number of charging terminals so that they can be charged while detecting the type and state of the battery pack with a charging stand. In this type of battery pack, it is difficult to connect all charging terminals to a charging stand so that poor contact does not occur. When the secondary battery is charged in a state where all the charging terminals are not normally electrically connected, for example, the battery is charged with a large current by mistake in identifying the type of the secondary battery incorporated in the battery pack, thereby deteriorating the battery performance. Alternatively, the battery may be charged in a state where the battery temperature cannot be normally detected, and the battery performance may be degraded.

[0004] Furthermore, even when the portable electric device is carried in a pocket or a bag, the battery pack that allows the charging terminal to be exposed even when the portable electric device is attached to the portable electric device is made of metal or metal. There are also adverse effects such as a short circuit caused by the chain contacting the charging terminal.

In order to solve such disadvantages, a battery pack has been developed which is mounted on a portable electric device without using a charging terminal exposed to the outside and is charged by supplying power from the portable electric device. Have been. The battery pack is not charged directly by the charging stand, but is charged via the portable electric device. In a portable electric device, electric power is transferred from a charging stand in a contactless state. The portable electric device includes a secondary coil that is electromagnetically coupled to a primary coil of the charging stand. The primary coil of the charging stand carries power to the secondary coil of the portable electric device by electromagnetic induction. The portable electric device rectifies an alternating current induced in the secondary coil and converts it into a direct current. The direct current is controlled by a control circuit and supplied to the battery pack to charge the secondary battery. The battery pack and the portable electric device are connected via a charge / discharge terminal. When charging the battery pack, the portable electric device is mounted on a charging stand. In this state, power is supplied from the primary coil of the charging stand to the secondary coil of the portable electric device, the output of the secondary coil is controlled by the control circuit, and power is supplied from the portable electric device to the battery pack. The next battery is charged. When the portable electric device is removed from the charging stand, power is supplied from the battery pack to the portable electric device, and the portable electric device can be used.

[0006]

The battery pack charged by the portable electric device as described above does not require the charging terminal to be exposed to the outside when the portable electric device is attached to the portable electric device. Need not be connected via a contact. Therefore, there is a feature that the battery pack can be charged without contact by mounting the portable electric device on the charging stand. However, the battery pack having this structure cannot be charged while being detached from the portable electric device. For this reason, there is a drawback that a spare battery pack cannot be mounted on the charging stand and charged while the portable electric device is used.

Further, the battery pack having this structure may be charged by being connected to a portable electric device via a signal terminal in addition to a +/- charge / discharge terminal. This battery pack is
If the signal terminal becomes defective, normal charging cannot be performed. Further, in this state, there is a case where the battery cannot be safely charged, or the battery performance is remarkably reduced by charging. The charging circuit built into the portable electric device,
This is because the type of the battery pack cannot be detected normally.

[0008] Further, a system for charging a battery pack by transferring electric power from a charging stand to a portable electric device by electromagnetic induction is described below.
It may be difficult to arrange the secondary coil at the optimal position of the portable electric device. In particular, a portable electric device having a battery pack mounted on the back has a disadvantage that it is difficult to arrange a secondary coil at an optimum position. This is because the lower part of the case of the portable electric device, which is optimal for incorporating the secondary coil, becomes very thin.

A first object of the present invention is to solve such a drawback, that is, to provide a battery pack and a charging stand which can charge a secondary battery without contact without providing a charging terminal in the battery pack. To provide. Further, another important object of the present invention is to provide a battery pack that can eliminate poor charging caused by poor contact and can charge a secondary battery in an ideal state, safely, and without deteriorating battery performance. To provide a charging stand.

[0010]

Means for Solving the Problems A first invention of the present invention is:
The charging stand 1 has a built-in primary coil 13 excited by an alternating current, and the battery pack 2 has a built-in secondary coil 14 electromagnetically coupled to the primary coil 13 and a control circuit 20. The battery pack 2 charges the built-in secondary battery 11 while controlling the AC power induced in the secondary coil 14 by the built-in control circuit 20. Further, the battery pack 2 includes the outer can 1
2 has a built-in secondary battery 11 made of iron or an iron alloy.

A battery pack 2 containing a secondary coil 14
Needs to arrange the secondary coil 14 close to the secondary battery 11. This is because the secondary battery 11 and the secondary coil 14 are built in the small battery pack 2. The electric power induced in the secondary coil 14 built in this state is affected by the metal disposed around, that is, the outer can 12 of the secondary battery 11. This is because the outer can 12 changes the magnetic flux radiated from the primary coil 13.

In order to reduce the overall weight, the battery pack 2 uses a type in which the external can 12 is made of aluminum for the built-in secondary battery 11. However, when the secondary coil 14 is disposed close to the aluminum outer can 12, the power that can be transferred from the primary coil 13 to the secondary coil 14 is significantly reduced. FIG. 1 shows that the voltage-current characteristic of the secondary coil 14 arranged in parallel close to the primary coil 13 is affected by the aluminum plate arranged close to the secondary coil 14. ing. FIG. 2 shows that the secondary coil 14 is changed under the same conditions by changing the aluminum plate to an iron plate.
Is a result of measuring the voltage-current characteristics of FIG.

This figure was measured under the following conditions. The primary coil 13 and the drive circuit are TDK MSE177E for cordless phones. Secondary coil 14 is made of TDK M for cordless telephone.
SE177F. A DC of 141 V is applied to the primary coil 13 for 120 k.
Alternating current switching at a frequency of Hz was applied. The distance between the primary coil 13 and the secondary coil 14 is 4 mm. The output of the secondary coil 14 is a diode (RK33)
And smoothed with a smoothing condenser (200 μF). An aluminum plate or iron was arranged in parallel with the secondary coil 14 on the opposite side of the primary coil 13. Aluminum plate and iron are 2mm thick, 30x length and width
It is set to 50 mm. The primary coil 13 and the secondary coil 14 were disposed at the center of an aluminum plate or an iron plate with a winding outer shape of about 20 × 30 mm. The distance between the aluminum plate and the iron plate and the secondary coil 14 was changed to 0 to 8 mm, and the voltage-current characteristics induced in the secondary coil 14 were measured.

As is apparent from FIGS. 1 and 2, the output voltage of the secondary coil 14 close to the aluminum plate is considerably lower than that of the iron plate at the same load current. This means that when a secondary battery having an aluminum outer can approaches the secondary coil 14, the current induced in the secondary coil 14 is extremely reduced, and power cannot be efficiently transferred. The battery pack of the present invention comprises an outer can 1
Since 2 is made of iron, the induction power of the secondary coil 14 can be increased as compared with a case in which a secondary battery of an aluminum outer can is built in.

In particular, as the secondary coil 14 comes closer to the outer can 12, its characteristics become more remarkable. As shown by ● in FIG. 1, the output voltage of the secondary coil 14 which is in close contact with the aluminum plate is reduced by as much as 80% as compared with the state without the aluminum plate, and the secondary coil 14 can hardly be used. On the contrary,
The secondary coil 14 in close contact with the iron plate has a higher output voltage than a state without the iron plate in a region where the load current is small, as shown by ● in FIG. 2, and can output a considerable current.
Therefore, the secondary coil 1 is attached to the secondary battery 11 having an iron outer can.
The battery pack according to the present invention, in which the battery packs 4 are arranged close to each other, has a feature that the external shape is compact and the battery can be efficiently guided to the secondary coil 14.

In a battery pack in which the outer can 12 is made of iron or an iron alloy, the outer can 12 is made of, for example, stainless steel, or is made of iron whose surface is metal-plated.

According to a second aspect of the present invention, a charging stand 1 having a built-in primary coil 13 excited by an alternating current,
The battery pack 2 includes a secondary coil 14 and a control circuit 20 which are electromagnetically coupled to the battery pack 2. The battery pack 2 has a built-in rectangular secondary battery 11 wider than its thickness, and the outer can 12 of the rectangular battery has wide front and back surfaces 12 located at the front and rear.
A and a narrow surface composed of both side surfaces 12B and upper and lower surfaces 12C. The secondary coil 14 is arranged apart from the wide front and back surfaces 12A of the rectangular outer can 12 and close to the narrow surface.

In this battery pack, the relative position between the secondary coil 14 and the rectangular secondary battery 11 is specified, and the secondary coil 1
4 is improved. 3 to 5
Shows the voltage-current characteristics of the secondary coil 14 disposed close to the prismatic battery having an aluminum outer can. FIGS. 6 to 8 show voltage-current characteristics of the secondary coil 14 disposed close to the square battery having an iron outer can. 3 and 6
Is a secondary coil 14 disposed close to the wide front and back surfaces 12A of the outer can 12 of the prismatic secondary battery 11 shown in FIG.
3 shows the voltage-current characteristics of FIG. FIGS. 4 and 7 show the voltage-current characteristics of the secondary coil 14 disposed close to the side surface 12B of the outer can 12 of the rectangular secondary battery 11 shown in FIG. FIG. 8 shows a voltage-current characteristic of the secondary coil 14 disposed close to the upper and lower surfaces 12 </ b> C of the outer can 12.

These figures are the same as in the measurements of FIGS. 1 and 2 except that the aluminum plate and the iron plate are changed to a secondary battery 11 having an aluminum outer can and a secondary battery 11 having an iron outer can. Measured. However, the secondary battery 11 having the following dimensions was used. The secondary battery 11 having an aluminum outer can is provided with an outer can 12.
The outline of thickness x width x height is 8.1 x 22 mm x 48
mm. The secondary battery 11 in an iron outer can has the outer shape of the outer can 12,
One having a thickness x width x height of 6.1 x 17 mm x 48 mm was used. The distance between the outer can 12 of the secondary battery 11 and the secondary coil 14 was changed to 0 to 8 mm, and voltage-current characteristics induced in the secondary coil 14 were measured.

As shown in FIGS. 3 and 6, the secondary coil 14 disposed on the wide front and back surfaces 12A of the prismatic battery has considerably reduced voltage-current characteristics. In particular, as the secondary coil 14 approaches the wide front and back surfaces 12A of the outer can 12, the voltage-current characteristics of the secondary coil 14 decrease. On the other hand, as shown in FIGS. 4 and 7 and FIGS. 5 and 8, the secondary coil 14 disposed close to the narrow surface of the outer can 12
, The voltage-current characteristics do not decrease so much, and the voltage-current characteristics can be significantly improved as compared with the secondary coil 14 disposed on the wide front and back surfaces 12A.

The battery pack 2 in which the secondary coil 14 is built in close to the narrow surface of the battery pack 2 has a built-in outer casing 12 of the built-in secondary battery 11 made of iron, stainless steel or other iron alloy, or aluminum. And

[0022]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate a charging stand for embodying the technical idea of the present invention and a battery pack mounted on the charging stand, and the present invention relates to a battery pack and a charging stand described below. Not specific to

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”.
However, the members described in the claims are not limited to the members of the embodiments.

FIGS. 10 and 11 show a charging stand 1 and a battery pack 2 mounted on the charging stand 1. The battery pack 2 in this figure is detachably attached to the back of the portable electric device 3,
It is attached to the charging stand 1 via the portable electric device 3. The charging stand 1 has a mounting portion 1A for mounting the portable electric device 3 on which the battery pack 2 is mounted in a fixed position. Although the portable electric device 3 in this figure is a mobile phone, the present invention
Is not specified as a mobile phone. The portable electric device to which the battery pack is mounted may be, for example, an electric razor or an electric toothbrush.

The battery pack 2 supplies electric power to the portable electric device 3. Therefore, the battery pack 2 has the discharge terminal 5 exposed outside the case 4. The portable electric device 3
It has a power supply terminal 6 that is in contact with the discharge terminal 5 and is electrically connected with the battery pack 2 mounted. Battery pack 2 shown
Is provided on the mounting surface of the portable electric device 3 with a discharge terminal 5 exposed on an opposite surface. The discharge terminal 5 provided here is
The battery pack 2 is mounted on the portable electric device 3 and is brought into contact with the power supply terminal 6 provided on the portable electric device 3.

The battery pack 2 is provided with a hook protrusion 7 at the lower end of the case 4 and a hook recess 8 at the upper end surface of the case 4.
The hook protrusion 7 is inserted into a hook portion 9 provided on the case 4 of the portable electric device 3. The lock recess 10 provided in the portable electric device 3 is elastically inserted into the hook recess 8. The battery pack 2 having this structure is detached from the portable electric device 3 by moving the lock 10 upward. The lock device 10 is elastically inserted into the hooking concave portion 8 and is mounted on the portable electric device 3 so that the mounted battery pack 2 does not come off. The battery pack 2 having this structure can be easily attached to and detached from the portable electric device 3 by operating the lock device 10. However, in the present invention, the structure for mounting the battery pack to the portable electric device is not limited to the above-described structure, but may be any structure that can be detachably mounted to the portable electric device.

The battery pack 2 does not have a charging terminal.
By the action of electromagnetic induction, electric power is transferred from the charging stand 1 to charge the secondary battery 11. The charging stand 1 has a built-in primary coil 13 and the battery pack 2 has a built-in secondary coil 14 for transferring power by the action of electromagnetic induction. The primary coil 13 and the secondary coil 14 are electromagnetically coupled, and power is transferred from the primary coil 13 to the secondary coil 14. In order to efficiently transfer power from the primary coil 13 to the secondary coil 14, the primary coil 13 and the secondary coil 14 are arranged as close as possible.

The charging stand 1 has a primary coil 13 disposed on the inner surface of the mounting surface. The primary coil 13 is connected to a power supply circuit 15, as shown in the circuit diagram of FIG. Power supply circuit 1
Reference numeral 5 denotes a rectifier circuit 16 that converts an alternating current of a commercial power supply to a direct current by a diode and converts it into a smooth direct current by a smoothing capacitor, and an FET that is a switching element 17 connected in series with the primary coil 13. And an oscillation circuit 18 for switching the switching element 17 on and off. The oscillation circuit 18 is, for example, 50 kHz to 500 kHz.
Hz, preferably at a frequency of about 100 kHz, switches the switching element 17 on and off. The switching element 17 switches DC output from the rectifier circuit 16 to excite the primary coil 13 with AC. As shown in FIG. 11, a ferrite core 19 is provided at the center of the primary coil 13 in order to efficiently transfer power to the secondary coil 14 by the action of electromagnetic induction.

The battery pack 2 includes a secondary battery 11 and a secondary coil 14 electromagnetically coupled to the primary coil 13 of the charging stand 1.
And a control circuit 20 for converting the AC output of the secondary coil 14 to DC to control the state of charge of the secondary battery 11 and, when the battery is used in an abnormal state, shut off the current to protect the battery. And a protection circuit 21 to be used.

The battery pack 2 is preferably a secondary battery 1
1 is provided with a lithium ion secondary battery. The pack battery of the lithium ion secondary battery is light and can increase the chargeable capacity. However, a nickel-hydrogen battery or a nickel-cadmium battery can be incorporated as a secondary battery. Nickel-cadmium batteries can be discharged with a large current, and nickel-hydrogen batteries have the advantage of being able to increase the charge capacity per volume.

As shown in FIG. 10 and FIG. 11, the secondary coil 14 is mounted in a state where the portable electric device 3 is mounted on the charging stand 1.
In the case 4 of the battery pack 2, it is disposed on the bottom surface facing the primary coil 13 so as to be disposed close to the primary coil 13. The secondary coil 14 preferably has no core as an air core in order to make the battery pack 2 lighter.
However, a core can also be provided in the secondary coil, and power can be efficiently transferred from the primary coil to the secondary coil by the action of electromagnetic induction.

As shown in the circuit diagram of FIG. 12, the control circuit 20 includes a rectifier circuit 22 for rectifying an alternating current output to the secondary coil 14 and converting the alternating current to a direct current. A charging control unit 23 connected in series with the secondary battery 11 to control the state of charge of the secondary battery 11; an arithmetic circuit 24 for controlling the charging control unit 23; A current detection unit 25 for inputting a charging current of
A voltage detector 26 for inputting an input voltage to the arithmetic circuit 24;

The charge control unit 23 controls the output of the rectifier circuit 22 to a voltage and a current optimum for charging the secondary battery 11, and stops charging when the secondary battery 11 is fully charged. Therefore, the charging control unit 23 includes a constant voltage / constant current circuit for stabilizing the output of the rectifier circuit 22 and the arithmetic circuit 2
4 and a switching element for stopping charging when the secondary battery 11 is fully charged. The constant voltage / constant current circuit detects the charging current and the battery voltage and controls the output to a constant current and a constant voltage. The switching element is connected in series with the secondary battery 11. When the switching element is on, the secondary battery 11 is charged, and when the switching element is turned off, charging is stopped.

The arithmetic circuit 24 detects the charging current and voltage of the secondary battery 11 and controls the switching element of the charging control unit 23. The arithmetic circuit 24 turns on the switching element until the secondary battery 11 is fully charged,
When is fully charged, switching from on to off stops charging. The lithium ion secondary battery can detect a full charge by detecting a charging current or a battery voltage. The lithium ion secondary battery is charged at a constant current first, and then charged at a constant voltage to be fully charged. In the constant voltage charging step, the charging current decreases as the battery becomes fully charged.
Therefore, it is possible to detect that the charging current has become smaller than the set value, determine that the battery is fully charged, and stop charging. Further, when the battery voltage rises to the set voltage, it can be determined that the battery is fully charged, and the charging can be stopped.

The nickel-hydrogen battery and the nickel-cadmium battery are fully charged by constant current charging. This type of secondary battery has a property that when fully charged, the battery voltage slightly decreases. For this reason, it is possible to detect that the battery voltage has dropped, that is, ΔV, to detect full charge.

The protection circuit 21 detects the battery voltage and the current flowing in the battery, and controls the switching element of the control unit 27 to turn on and off. When the battery voltage becomes higher or lower than the set voltage, the switching element of the control unit 27 is turned off to cut off the current. Further, when an abnormally large current flows through the battery, the switching element is turned off to cut off the current.

In the battery pack 2 shown in the figure, the control circuit 20 and the protection circuit 21 are composed of separate circuits. However, the operation circuit of the control circuit may be provided with the function of a protection circuit, and the control circuit may be used in combination with the protection circuit. Further, the switching element of the charge control unit can be used together with the switching element controlled by the protection circuit. The arithmetic circuit can be realized by an analog circuit that processes analog signals such as voltage and current and controls the switching elements, or can be configured by a microprocessor such as a one-chip microcomputer. The arithmetic circuit of the microprocessor converts the voltage and the current into a digital signal by an A / D converter and performs the operation.

The arithmetic circuit of the microprocessor used in combination with the control circuit and the protection circuit controls the switching element according to the flowchart of FIG. In the flowchart in this figure, the microprocessor turns on the switching element only when the secondary battery is not fully charged and the battery voltage and the current are within a set range.
When the battery is fully charged, or when the battery voltage and current are not within the set ranges, the switching element is turned off.

The battery pack 2 shown in FIGS. 10 and 11 has a secondary coil 14 disposed below the secondary battery 11. The secondary coil 14 is disposed below the secondary battery 11 and at the bottom of the case 4. The secondary coil 14 is disposed at the bottom of the case 4 with the central axis being the longitudinal direction of the case 4 and the battery, and the vertical direction in the figure.

The case 4 of the battery pack 2 is formed by molding plastic into a thin rectangular box shape, and incorporates a rectangular secondary battery 11 inside. The prismatic secondary battery 11 has a prismatic outer can 12 wider than its thickness. Outer can 1
Reference numeral 2 denotes a shape in which the peripheries of the wide front and back surfaces 12A located at the front and rear are connected by a narrow surface. Narrow surface is wide front and back 1
It comprises both side surfaces 12B connecting both edges of 2A, and upper and lower surfaces 12C connecting upper and lower edges of the wide front and back surfaces 12A.

The height of the square case 4 is higher than that of the square secondary battery 11, and a gap is provided at the bottom of the square case 4.
Here, the secondary coil 14 and the printed circuit board 28 are provided. The outer diameter of the secondary coil 14 and the width of the printed circuit board 28 are substantially equal to the thickness of the rectangular secondary battery 11, and are disposed below the rectangular secondary battery 11. Printed circuit board 28
Are disposed insulated from the secondary battery 11. The printed circuit board 28 is an electronic part 2 for realizing a control circuit and a protection circuit.
9 is installed.

Further, the battery pack 2 shown in FIGS. 14 and 15 has a rectangular case 4 in which a rectangular secondary battery 11 is built.
The secondary coil 14 is built in the side of the prismatic secondary battery 11. The secondary coil 14 is disposed on the side of the case 4 with the central axis being the longitudinal direction of the case 4 and the battery, and the vertical direction in the figure. The rectangular case 4 has a width wider than that of the rectangular secondary battery 11, and a gap is provided on a side portion of the rectangular case 4. In the gap, the secondary coil 14 is provided at the lower part, and the printed circuit board 28 is provided at the upper part. The battery pack 2 in this figure has the same structure as the battery pack 2 shown in FIGS. 10 and 11, and can be detachably attached to the portable electric device 3.

In the battery pack 2 of FIG. 16, a secondary coil 14 and a printed circuit board 28 are provided below the rectangular secondary battery 11 and at the bottom of the case 4. In the battery pack 2 shown in this figure, the central axis of the secondary coil 14 is disposed at the bottom of the case 4 with the lateral direction of the case 4 and the battery, that is, the horizontal direction in the figure. The primary coil 13 and the secondary coil 14 are arranged with their central axes arranged on a straight line. Therefore, the primary coil 13 that transfers power to the secondary coil 14 disposed in this direction is built in the charging stand 1 with the central axis left and right as shown in FIG.

In the above battery pack, the secondary coil 14 is
The rectangular secondary battery 11 is arranged apart from the wide front and back surfaces 12A of the rectangular secondary battery 11 and close to the narrow surface. Battery pack 2 of this structure
The outer case 12 of the prismatic secondary battery 11 can be made of aluminum, an aluminum alloy, iron, or an iron alloy. That is, the secondary coil 14 arranged here is
This is because the influence from the outer can 12 can be reduced.

The battery pack 2 shown in FIG.
Are disposed in close contact with the wide front and back surfaces 12A of the rectangular secondary battery 11. In the battery pack 2, the case 4 is made thicker than the rectangular secondary battery 11, and the secondary coil 14 is built therein in close contact with the wide front and back surfaces 12 </ b> A of the rectangular secondary battery 11. The secondary coil 14 has a central axis having a wide front and back surface 12A.
And the case 4 of the battery pack 2
It is built in. The charging stand 1 incorporates the primary coil 13 at a position close to the secondary coil 14 so that the central axes of the secondary coil 14 and the primary coil 13 are linear.

In the battery pack 2 in which the secondary coil 14 is disposed on the wide front and back surfaces 12A of the rectangular secondary battery 11, the outer can 12 of the built-in secondary battery 11 is made of iron or an iron alloy. The outer can 12 of the prismatic secondary battery 11 is
4, the outer can 12 is made of aluminum or aluminum alloy.
This is because the voltage-current characteristics output from the device 4 decrease. The outer case 12 made of iron is preferably one whose surface is plated with a metal such as nickel or chrome so as not to rust. Further, the outer can 12 made of an iron alloy is preferably made of a metal such as stainless steel that is resistant to rust.

Further, the battery pack 2 shown in FIG. 18 has a cylindrical case 4 in which a cylindrical secondary battery 11 whose outer can 12 is made of iron or an iron alloy is built. At the bottom of the case 4, a printed circuit board 28 having an outer shape substantially equal to the outer shape of the battery is provided. The printed circuit board 28 is provided with electronic parts 29 for realizing a control circuit and the like on the surface facing the battery, and the spirally wound secondary coil 14 is fixed on the surface on the bottom side of the battery pack 2. I have. Battery pack 2 of this shape
Is characterized in that the secondary coil 14 wound in a circular shape can be housed in the battery pack 2 so as not to waste space. The battery pack 2 of this shape is inserted into a cylindrical insertion portion (not shown) provided at the bottom of the portable electric device, attached to the portable electric device, set on a charging stand via the portable electric device, and charged. it can.

The above-described battery pack is mounted on a portable electric device, and is charged by mounting the portable electric device on a charging stand. However, the above-described battery pack can be directly mounted on a charging stand and charged without being mounted on a portable electric device.

[0049]

According to the charging stand of the present invention and the battery pack mounted on the charging stand, the battery pack can be charged in a contactless manner without providing a charging terminal for the battery pack mounted on the portable electric device. That is, the battery pack of the present invention has both a secondary coil and a control circuit built-in, and a charging stand has a built-in primary coil, and power is transmitted from the primary coil to the secondary coil of the battery pack by electromagnetic induction. This is because the secondary battery is transported and charged. That is, the battery pack does not need to be charged by supplying charging power from the portable electric device, and can control the power induced in the built-in secondary coil by the control circuit to charge the secondary battery. Therefore, the battery pack does not need to be connected to the portable electric device via a contact for charging. The battery pack is a built-in control circuit.
Fully charged while monitoring the state of charge of the secondary battery. The battery pack charged in this state does not need to connect the charging terminal to the portable electric device and the charging stand,
There is no need to connect a terminal for detecting the state or type of the battery to be charged. The battery pack is charged in an ideal state with no contact.

Further, the battery pack and the charging stand of the present invention
Charging power is supplied directly from the charging stand to the battery pack in a non-contact state by utilizing the action of electromagnetic induction without using a portable electric device to charge the battery pack. The battery pack charged in this state can be charged by the charging stand without the intervention of the portable electric device. Therefore, if necessary, the battery pack can be directly charged at the charging stand without being attached to the portable electric device. This structure realizes a feature that a spare battery pack can be charged by a charging stand and used conveniently.

Further, the battery pack and the charging stand of the present invention
Eliminating poor charging of the secondary battery due to poor contact of the charging contact makes it possible to charge the secondary battery safely in an ideal state without lowering battery performance. This is because the battery pack of the present invention incorporates both the secondary coil and the control circuit, and controls the power induced in the secondary coil by the control circuit to charge the secondary battery.

Furthermore, a battery pack containing a secondary battery in an outer can made of iron or an iron alloy has a structure in which the secondary coil is disposed close to the secondary battery, but the primary coil is replaced with the secondary coil. Has the feature that power can be transferred efficiently. In particular, the secondary coil is susceptible to the influence of the outer can, and is disposed on the wide front and back surfaces of the rectangular battery, so that power can be efficiently transferred from the primary coil to the secondary coil.

Further, a battery pack in which a secondary coil is disposed on a narrow surface of a rectangular battery, away from the wide front and back surfaces of the battery,
There is a feature that power can be efficiently transferred from the primary coil to the secondary coil by reducing the influence of the rectangular outer can. Since the secondary coil placed at this position can reduce the influence of the outer can, it can be made of aluminum or aluminum alloy without specifying the outer can as iron, and the power can be efficiently supplied from the primary coil to the secondary coil. There is a feature that can be transported.

[Brief description of the drawings]

FIG. 1 is a graph showing a voltage-current characteristic of a secondary coil arranged close to an aluminum plate.

FIG. 2 shows the voltage of a secondary coil disposed close to an iron plate.
Graph showing current characteristics

FIG. 3 is a graph showing the voltage-current characteristics of a secondary coil arranged close to the wide front and back surfaces of an aluminum outer can.

FIG. 4 is a graph showing voltage-current characteristics of a secondary coil disposed close to a side surface of an aluminum outer can.

FIG. 5 is a graph showing voltage-current characteristics of a secondary coil disposed close to upper and lower surfaces of an aluminum outer can.

FIG. 6 is a graph showing voltage-current characteristics of a secondary coil disposed close to the wide front and back surfaces of an iron outer can.

FIG. 7 is a graph showing a voltage-current characteristic of a secondary coil disposed close to a side surface of an iron outer can.

FIG. 8 is a graph showing voltage-current characteristics of a secondary coil disposed close to upper and lower surfaces of an iron outer can.

FIG. 9 is a perspective view showing a state in which a secondary coil is disposed in proximity to an outer can of a prismatic secondary battery.

FIG. 10 is a vertical cross-sectional view of a charging stand according to an embodiment of the present invention and a battery pack mounted on the charging stand.

11 is a vertical vertical sectional view of the charging stand shown in FIG. 10 and a battery pack mounted on the charging stand.

FIG. 12 is a circuit diagram of a charging stand according to an embodiment of the present invention and a battery pack mounted on the charging stand.

FIG. 13 is a flowchart of an operation circuit of a microprocessor used in a control circuit and a protection circuit according to another embodiment of the present invention.

FIG. 14 is a vertical cross-sectional view of a charging stand and a battery pack mounted on the charging stand according to another embodiment of the present invention.

15 is a vertical longitudinal sectional view of the charging stand shown in FIG. 14 and a battery pack mounted on the charging stand.

FIG. 16 is a vertical cross-sectional view of a charging stand and a battery pack mounted on the charging stand according to still another embodiment of the present invention.

FIG. 17 is a vertical longitudinal sectional view of a charging stand and a battery pack mounted on the charging stand according to still another embodiment of the present invention.

FIG. 18 is a sectional view of a battery pack according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Charge stand 1A ... Mounting part 2 ... Pack battery 3 ... Portable electric equipment 4 ... Case 5 ... Discharge terminal 6 ... Power supply terminal 7 ... Hook protrusion 8 ... Hook recess 9 ... Hook part 10 ... Locking tool 11 ... Secondary battery 12: Exterior can 12A: Wide front and back
12B ... side surface 12C ... upper and lower surfaces 13 ... primary coil 14 ... secondary coil 15 ... power supply circuit 16 ... rectification circuit 17 ... switching element 18 ... oscillation circuit 19 ... ferrite core 20 ... control circuit 21 ... protection circuit 22 ... rectification circuit 23 ... Charge control unit 24 arithmetic circuit 25 current detection unit 26 voltage detection unit 27 control unit 28 printed circuit board 29 electronic parts

Claims (8)

[Claims] A charging stand (1) containing a primary coil (13) excited by an alternating current, and a secondary coil (14) electromagnetically coupled to the primary coil (13). A battery pack (2) that charges a built-in rechargeable battery (11) while being controlled by a control circuit (20) containing built-in AC power induced in a coil (14)
Wherein the outer can (12) of the secondary battery (11) incorporated in the battery pack (2) containing the secondary coil (14) is made of iron or an iron alloy. A charging stand and a battery pack to be attached to the charging stand. 2. A secondary battery (1) built in a battery pack (2).
2. The charging stand according to claim 1, wherein the outer can of (1) is made of stainless steel, and a battery pack mounted on the charging stand. 3. A rechargeable battery (1) built in a battery pack (2).
2. The charging stand according to claim 1, wherein the outer can (12) of 1) is made of iron whose surface is metal-plated, and a battery pack mounted on the charging stand. 4. A charging stand (1) containing a primary coil (13) excited by an alternating current, and a secondary coil (14) electromagnetically coupled to the primary coil (13). A battery pack (2) that charges a built-in rechargeable battery (11) while being controlled by a control circuit (20) containing built-in AC power induced in a coil (14)
The battery pack (2) is a rectangular secondary battery that is wider than its thickness.
(11), and the outer can (12) of the prismatic battery has wide front and back surfaces (12A) located on the front and back, both sides (12B) and upper and lower surfaces (1
2C), the secondary coil (14) is separated from the wide front and back surfaces (12A) of the outer can (12) of the secondary battery (11), and approaches the narrow surface. A charging stand characterized by being provided, and a battery pack mounted on the charging stand. 5. The charging stand according to claim 4, wherein the outer can of the secondary battery is made of iron or an iron alloy, and a battery pack mounted on the charging stand. 6. The charging stand according to claim 4, wherein the outer can (12) of the secondary battery (11) is made of stainless steel, and a battery pack mounted on the charging stand. 7. The charging stand according to claim 4, wherein the outer can (12) of the secondary battery (11) is made of iron whose surface is metal-plated, and a battery pack mounted on the charging stand. 8. The charging stand according to claim 4, wherein the outer can (12) of the secondary battery (11) is made of aluminum or an aluminum alloy, and a battery pack mounted on the charging stand.