WO1997045997A1

WO1997045997A1 - Battery charging unit

Info

Publication number: WO1997045997A1
Application number: PCT/GB1997/001345
Authority: WO
Inventors: Nils Martensson
Original assignee: Ipr Industries Ltd.
Priority date: 1996-05-31
Filing date: 1997-05-16
Publication date: 1997-12-04
Also published as: GB2313722A; AU2904797A; GB9709847D0

Abstract

According to the invention there is provided a battery charging unit comprising a housing, said housing having a current supply means provided therein for supplying current to an electrical or electronic apparatus located remote from the battery charging unit, said housing comprising mains coupling means for a conventional plug socket, and battery coupling means comprising a recess and contacts for mounting a battery in the housing such that current from the current supply means is supplied to the battery mounted therein, said housing also comprising apparatus coupling means. The battery is preferably supported by the conventional plug socket. Additionally the current from the current supply means is supplied to said electrical or electronic apparatus and said battery simultaneously, in order to charge said electrical or electronic apparatus and said battery simultaneously.

Description

BATTERY CHARGING UNIT

The present invention relates to a battery charging unit for an electrical or electronic device, particularly, although not exclusively, for a cellular radio telephone.

Commonly, portable cellular radio telephones are provided with removable batteries as their current source. Typically, these batteries are Nickel - Cadmium (Ni - Cd) batteries which are rechargeable.

To recharge the battery, the battery is left attached to the cellular radio telephone, and is recharged "in situ" by means of a charging unit. The charging unit is coupled to a mains alternating current (AC) supply via a conventional plug arrangement (in the United Kingdom, this is a 3 - pin arrangement well known to persons skilled in the art), and is coupled to the battery via a two - conductor cable to the telephone and, through internal circuitry, to the battery to be recharged. Respective matching contacts are provided, on the casing of the telephone, and in a plug terminating the free end of the cable, to couple current to the telephone and battery. The charger, typically, may be a simple transformer/constant current generator, as is well known to persons skilled in the art. The telephone may be provided with control logic and means to sense one or more parameters, for example battery temperature, these being indicative of the charge state of the battery. By monitoring such parameters, one is able to ensure that the battery is optimally recharged. Wilh this method of recharging, the battery is "fast - charged", that is where a constant current of, for example, 600 - 1000 mA is supplied to the battery to effect recharging. The telephone can still be used while the battery is being recharged.

So - called desk chargers are commonly provided for portable cellular radio telephones. These desk chargers comprise desk stands adapted to stand on a desk or other flat surface, with a recess for receiving the telephone with a battery attached thereto. The stand has a cable, which is coupled to a charging unit - similar to the one described above - which is coupled to the mains supply. Contacts are provided in the recess to contact respective contacts provided on the telephone casing. These are for providing current to the battery for recharging, and for use in monitoring other parameters, for example, temperature, and which are used to provide optimum charging as described previously. The desk stand may also incorporate a second recess for receiving a second, "spare" battery, to allow this battery to be recharged at the same time. Usually, while the battery being charged "in situ" is being "fast" charged, the second battery is "slow" charged, or "trickle" charged. This slow - charging may use a pulsating current to provide a net current of around 60 - 100 mA or a constant current of around 60 - 100 mA, and is well known to persons skilled in the art.

In order to fast - charge a battery, control logic is required to control the charging. This control logic - usually in the form of a microprocessor - is usually located in the telephone because of the extra space that this control logic requires, but it may be located in the charging unit or, rarely, in the battery itself. Slow charging does not require the same control logic

Among the many accessories available for portable cellular radio telephones, are so - called "travel chargers". These take the form of a charging unit - incorporating a transformer/constant current generator, with a pin arrangement for coupling it to the mains supply. The casing for the charging unit is provided with a recess for receiving a spare battery. Contacts are provided within the recess for contacting matching contacts on the battery. A "trickle" current is supplied to the battery when the charging unit is coupled to the mains supply, thereby slow charging the battery received therein. The charging unit does not incorporate control logic for controlling fast charging, and therefore, is only capable of slow - charging a spare battery. This takes some time. There is the problem, therefore, that should the battery currently being used as the power supply for the telephone become discharged before spare battery is recharged, then the telephone is out of operation. Also, unfortunately, when the recess may be perfectly located when using a fiat mounted socket, should a wall mounted socket or any type of vertically arranged socket be used, the recess may then be at such an angle that the battery will not stay in the recess or, if it does, does not make contact with the contacts properly, making charging impossible.

According to the present invention, there is provided a battery charging unit comprising, a housing having a current supply means provided therein for supplying current to an electrical or electronic apparatus located remote from the battery charging unit, means for coupling the current supply means to a mains power supply, means for mounting a battery on the housing such that current from the current supply means is supplied to the battery mounted therein, and means for coupling the remote apparatus to the charging unit for supplying current, from the current supply means, thereto. This has the advantage of providing a compact and lightweight battery charging unit which is capable of charging a spare battery while also charging a battery in situ on a telephone.

By using a switch - mode power supply as the current supply, the dimensions of the charging unit can be kept small, and are mainly constrained by the dimensions of the battery, and the mains plug.

According to a second aspect of the invention, there is provided a battery charging unit comprising a housing having a current supply means provided therein for supplying current to an electrical or electronic apparatus located remote from the battery charging unit, coupling means provided on the housing for coupling the current supply means to a mains power supply, means for mounting a battery within the housing such that current is supplied from the current supply means to the battery mounted therein, the battery mounting means being provided such that the battery is mounted at an orientation whereby the longitudinal axis of the battery is at an acute angle to the horizontal and vertical axes of the housing. This has the advantage that the battery will always remain in situ whether the charging unit is plugged in horizontally or vertically.

The invention will now be described, by way of example only, with reference to the accompanying figures, of which:

figure 1 is an exploded perspective view of a charging unit in accordance with the invention, with a spare battery;

figure 2 is a perspective view of the charging unit of Figure 1 , with the cover in place;

figure 3 is a schematic block diagram illustrating the operation of the charging unit;

figure 4 is a schematic block diagram of a second embodiment of the invention;

figure 5 is a schematic block diagram of a third embodiment of the invention; and

figure 6 is a perspective view of a fourth embodiment of the invention. figure 7 is a perspective view of a further embodiment of a charging unit of the present invention;

figures 8a and 8b are views of a first portion of the side wall of the unit of figure 7 illustrating, in figure 8a the battery receiving recess uncovered, and, in figure 8b the battery receiving recess covered;

figure 9 schematically illustrates the charging unit of figure 7 plugged into a wall mounted mains socket with a spare battery in situ; and figure 10 schematically illustrates the charging unit of figure 7 plugged into a floor mounted mains socket with a spare battery in situ.

A charging unit 1 comprises a casing 2, made, for example, from a moulded plastic material in a known manner. In one face 9 of the casing 2, there is provided a recess 3 configured to accommodate a battery 10 to be charged. The recess 3 will be configured and dimensioned to accommodate the particular battery for which it is designed, and will have means for ensuring that the battery 10 is kept securely in place for charging. For example, the recess 3 may incorporate a groove 4 for co¬ operation with an elongated lug 5 provided on one end of the battery 10, and a gap 6 at the other end of the recess 3 to receive a flexible tongue 7 provided at the other end of the battery 10 so that the battery has a snap - fit within the recess 3. The battery 10 is inserted in the recess 3 by first placing the lug 5 within the groove 4, and then lowering the battery 10 into place so that the flexible tongue 7 snap - fits within the recess 6, thereby holding the battery 10 in place during charging. The battery 10 is simply removed by manually depressing the tongue 7, and using a gripper strip 18 to extract the battery from the recess 6 and then removing the lug 5 from the groove. Of course, any other means of removably securing the battery within the recess can be employed.

Also provided in the recess 3 - at a suitable location - are a number of contacts 17 for contacting matching contacts (not shown) provided on the battery 10. These contacts 17 include two contacts for supplying current to the battery, and may also include other contacts, for example, for use in monitoring parameters, e.g. battery temperature, which is indicative of the charge state of the battery 10. The use of such parameter monitoring to ensure that batteries are fully charged while not being overcharged is well known to persons skilled in the art. When the battery 10 is received in the recess 3, the respective contacts abut, thereby allowing current to be supplied to the battery 10 for recharging, while allowing the parameters to be sensed to ensure correct and optimal charging.

A removable cover 19 is provided for the recess 3 which protects the recess 3 when a battery 10 is not being charged or when the charging unit 1 is not in use. The cover 18 can be provided with appropriate lug (not shown), and tongue T to engage with respective grooves 4 and gap 6 in the recess 3 so that it can be snap fitted on to the casing 2 in the same manner used to retain the battery 10 in place. The cover 19 can be removed in the same way as the battery 10 using a gripper strip 18' provided on the flexible tongue T.

A wire or cable 8 extends from a second face 1 1. The cable 8 is of a known two - conductor type and terminates, at its free end, in a plug 12 configured to co-operate with a matching socket 26 provided in the housing 27 of the remote portable radio telephone 21. The cable 8 is coupled to a transformer/current generator arrangement 20 housed within the casing 2.

On a third face 13 of the casing 2, there is provided a conventional 2 - pin plug arrangement 14,15 i.e. current feed and return conductor, for coupling the mains supply 22 to current generator/transformer 20. A third " dummy " pin 16 may be provided, where the mains supply has a 3 - pin socket arrangement (for example in the United Kingdom).

In use, the charging unit 1 is plugged into the mains supply 22 using the external pins 14,15,16, and the cable plug 12 is connected to the telephone 21 with a battery 23 in situ. This will allow the telephone battery 23 to be fast - charged. Control logic 25 provided in the telephone controls fast - charging of the telephone battery 23 in a known manner. If required, a spare battery 10 can be placed in the recess 3 for slow - charging. In this way, it is possible to fast - charge a battery attached to a telephone, while, at the same time, slow - charging a spare battery. In an alternative embodiment, it would be possible for the cable plug 12 to be configured to connect to a desk stand 30 rather than a telephone per se, so as lo operate the desk stand 30 in the usual manner to fast - charge a telephone battery 23 and a second spare battery 31.

In a third embodiment of the invention, the charging unit 1 may also comprise control logic 24, operable to allow the spare battery 10 to be fast - charged when attached to the charging unit 1 when either the telephone battery 23 is fully charged or when no telephone 21 is coupled to the charging unit 1.

In fourth embodiment, the charging unit 1 can be provided with second, short, cable 28 coupling the transformer/generator 20 to a conventional plug 29 for coupling to a mains socket to replace the pins 14,15,16. This would allow the casing to be placed on the floor or other flat surface near the mains supply socket.

In all the embodiments, the charging unit 1 can use a transformer and rectifier circuit with means for current and over voltage limiting, or a conventional switch - mode power supply as the current generator arrangement with the control logic built in accordance with known techniques.

Referring now to the embodiment of figures 7 to 10, a battery charging unit 1 comprises a casing 2, made of a plastic material in a known manner.

The casing 2 has teardrop-shaped front and rear faces 3,4 and a continuous side wall 12. In a portion of the side wall 12 are provided a pair of pins 5a,5b adapted to be received into a conventional electrical socket, such as a wall socket, in order to to couple the battery charging unit 1 to a mains power supply. In the embodiment described herein, the pins 5a,5b are those for the US mains supply, but may equally well be of the three-pin type for the UK, or any other known pin arrangement.

In another portion of the side wall 12 there is provided a recess 6 into which may be placed a battery 7 to be recharged. In the interior of the recess 6 are a number of contacts 8 for contacting matching contacts (not shown) provided on the battery 7. These contacts 8 are used for supplying current to the battery 7 for recharging, and to monitor the charge state of the battery 7 to ensure optimum charging. The recharging of the battery is carried out in any known manner. For clarity, the electrical couplings and internal circuitry are not illustrated in the drawings. The couplings are achieved by any suitable known means.

A slidable cover 9 is provided to cover the recess 6 to prevent damage to the recess 6, and, in particular, the contacts 8, when the charging unit 1 is not being used to charge a battery in this way.

As described above, the battery charging unit 1 is provided wilh means to recharge a spare battery 7 by placing it in the recess 6. In use, the cover 9 is retracted and the spare battery 7 inserted in the recess 6 so that the contacts 8 contact the matching contacts on the spare battery 7.

The recess 6 is located in the side wall 12 at such a location, and dimensioned such that, when the charging unit 1 is plugged into a socket mounted on a wall 19 as illustrated in Figure 6, the spare battery 7 is oriented at an acute angle to the vertical- preferably around 45 degrees - so that the battery 7 remains in the recess 6 under gravity and the frictional fit within the recess 6. Similarly, when the charging unit 1 is plugged into a socket mounted on the floor 20, as illustrated in Figure 7, the battery 7 remains at an acute angle - again preferably around 45 degrees - to the vertical, and, therefore also remains in the recess. As will be understood to a person skilled in the art, various modifications arc possible within the scope of the present invention. For example, other shapes of battery charging unit are possible. The pin arrangement can be selected to correspond with the plug and socket convention of the region where the unit is to be used. Similarly, the recess is dimensioned to receive the appropriate battery. The recess can also be dimensioned to receive the whole telephone rather than simply the battery. The battery charger can be used to recharge batteries for other electrical or electronic apparatus, for example a portable personal computer.

The recess can be dimensioned and configured in any way, dependant upon the battery to be charged. In addition, the battery contacts and pins can be configured to suit the particular battery to be charged. Similarly, other socket and plug arrangements are possible both for the plug for the telephone, and for the plug for the mains supply socket. Any current generator which is able to supply the required current while being able to be housed within a suitable casing can be used. The cover can be slidable attached to the casing rather than removably attached to the casing to allow access to the recess. The cable can be a 3-conductor cable. The charging unit will of course be suitable for charging batteries for all sorts of applications, for example, video camcorders etc. The battery could be of any type, for example, Nickel Metal Hydride or Lithium Ion.

Claims

1. A battery charging unit comprising a housing, said housing having a current supply means provided therein for supplying current to an electrical or electronic apparatus located remote from the battery charging unit, said housing comprising mains coupling means for coupling the current supply means to a mains power supply, said housing also comprising battery coupling means for mounting a battery in the housing such that current from the current supply means is supplied to the battery mounted therein, said housing also comprising apparatus coupling means for coupling the remote apparatus to the charging unit for supplying current from the current supply means thereto, characterised in that said mains coupling means comprises a conventional pin arrangement which fits into a conventional plug socket, such that the battery charging unit is supported thereby.

2. A battery charging unit according to claim 1, characterised in that current from the current supply means is supplied to said electrical or electronic apparatus and said battery simultaneously, in order to charge said electrical or electronic apparatus and said battery simultaneously.

3. A battery charging unit according to claim 1, characterised in that said battery coupling means comprises a recess and contacts therein.

4. A battery charging unit according to claim 3, characterised in that the recess and battery comprise a co-operating lug and groove.

5. A battery charging unit according to claim 3, characterised in that said recess is configured to receive said battery therein, and that said battery is removably securable therein by securing means comprising a snap-fit mechanism.

6. A battery charging unit according to claim 5, characterised in that said snap- fit mechanism comprises a co-operating tongue and gap on the battery and recess.

7. A battery charging unit according to any of claims 4 to 6, characterised in that said securing means comprise a flexible tongue provided on the battery which snap-fits into a co-operating gap in the recess when the battery is received into the recess, the battery being removable from the recess by manually depressing said flexible tongue and extracting said tongue from said gap.

8. A battery charging unit according to claim 3, characterised in that said contacts include contacts for use in monitoring parameters such as battery temperature to indicate the charge state of the battery.

9. A battery charging unit according to claim 3, characterised in that said recess, when empty, is protected by an openable cover.

10. A battery charging unit according to claim 9, characterised in that said openable cover is secured in the closed position by cover securing means.

11. A battery charging unit according to any of claims 8 to 10, characterised in that said openable cover is removable.

12. A battery charging unit according to claim 8, characterised in that said openable cover is slidably attached to the housing.

13. A battery charging unit according to any preceding claim, characterised in that said apparatus coupling means comprises a cable, the free end of which terminates in a plug configured to co-operate with a matching socket provided in the housing of the remote electronic or electrical apparatus. n

14. A battery charging unit according lo any preceding claim, characterised in that said electrical or electronic apparatus comprises a portable cellular radio telephone.

15. A battery charging unit according to any preceding claim except claim 14, characterised in that said electrical or electronic apparatus comprises a desk stand battery charging device.

16. A battery charging unit according to any preceding claim, characterised in that the battery charging unit comprises control logic operable to allow the battery to be fast-charged when coupled to the battery charging unit when either the telephone battery is fully charged or when no telephone is coupled to the battery charging unit.

17. A battery charging unit comprising a housing having a current supply means provided therein for supplying current to an electrical or electronic apparatus located remote from the battery charging unit, coupling means provided on the housing for coupling the current supply means to a mains power supply, means for mounting a battery within the housing such that current is supplied from the current supply means to the battery mounted therein, the battery mounting means being provided such that the battery is mounted at an orientation whereby the longitudinal axis of the battery is at an acute angle to the horizontal and vertical axes of the housing.

18 A battery charging unit according to claim 17, wherein the acute angle is approximately 45 degrees. 9. A battery charging unit according to claim 17, wherein the battery to be mounted within the housing is part of an electrical or electronic apparatus, the whole apparatus being receivable in the recess.