WO1997001871A1

WO1997001871A1 - Battery pack and system for identifying a type of battery pack in an electrical apparatus

Info

Publication number: WO1997001871A1
Application number: PCT/CA1996/000435
Authority: WO
Inventors: Mohammed Tahmassebpur
Original assignee: Sierra Wireless, Inc.
Priority date: 1995-06-29
Filing date: 1996-06-27
Publication date: 1997-01-16
Also published as: AU6184496A

Abstract

A system for identifying a power source as a particular type of power source of a plurality of types of power sources usable with an electrical apparatus is disclosed. The system includes an electrical apparatus having a power source receptacle, a control mechanism, and four or more conductive pins electrically connected to the control mechanism and extending into the power source receptacle. The system further includes a plurality of types of power sources. Each of the types of power sources is removably receivable in the power source receptacle. At least some of the types of power sources have four or more points such that, when the power source is disposed in the power source receptacle, the four or more points contact corresponding ones of the four or more pins. A first one of the points is a positive terminal, a second one of the points is a ground terminal, and a thermistor is electrically connected between a third and a fourth one of the points. At least some of the types of power sources are of a first type of power source having a code. The code includes one of an electrical connection between the first and the fourth one of the points, an electrical connection between the second and the fourth one of the points, and no electrical connection to the fourth one of the points, such that the code identifies a power source as a particular type of the first type of power source. The control mechanism is programmable to read the code and identify a power source received in the power source receptacle as a particular type of the first type of power source. The control mechanism is programmable to automatically adjust internal programming of the electrical apparatus in response to identification of the particular type of the first type of power source. A power source and a method of making a power source are also disclosed.

Description

BATTERY PACK AND SYSTEM FOR IDENTIFYING A TYPE OF BATTERY PACK IN AN ELECTRICAL APPARATUS

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to battery packs and, more particularly, to battery packs and systems for identifying a type of battery pack in an electrical apparatus.

State of the Art

In electrical apparatus such as portable modems, it is often desirable to power the apparatus by means of battery power, preferably with rechargeable batteries. Various battery types, such as single cell alkaline, nickel metal hydride, nickel cadmium, and lithium batteries can be used in electrical devices. However, interchangeability between battery types usually presents a problem. Different types of batteries have different recharge requirements and, for example, one type of battery may require a low voltage charge over a long period of time, while another type of battery may require a high voltage charge over a short period of time. In addition, different types of batteries reach different voltages at the end of their charges, and require different methods for identifying when they are fully charged, half charged, and not charged. It would be desirable to provide a system for use in electrical apparatuses operable with different types of batteries wherein the electrical apparatus automatically identifies the type of battery being used and adjusts its internal programming in response to the type of battery identified. Batteries for use in electrical apparatus are often cylindrical in shape and electrically connected to one another. These batteries are generally received in battery receptacles in the electrical apparatus. The receptacles are generally shaped to conform to the contours of the batteries. To conserve on package length, it is desirable to position the batteries side by side, as opposed to end to end. It is also desirable to provide the batteries necessary for an electrical apparatus in a battery pack of two or more batteries secured together to ensure that the proper type of batteries necessary for the particular apparatus are used together. However, all known techniques for packaging batteries together require bulky packaging that increases the overall dimensions of the battery receptacle and, generally, the electrical apparatus. Further, when a battery receptacle is provided with a contoured surface for receiving a plurality of batteries positioned side by side, known packaging techniques in which flat surfaces surrounding the batteries are provided fail to accommodate the contours of the battery receptacle so that the battery pack does not properly fit into the receptacle. It is, therefore, desirable to provide a battery pack that permits packaging of a plurality of batteries side by side with minimal bulk. It is further desirable to provide such a battery pack that accommodates contours of a battery pack receptacle in an electrical apparatus.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a system for identifying a power source as a particular type of power source of a plurality of types of power sources usable with an electrical apparatus is provided. The system includes an electrical apparatus having a power source receptacle, a control mechanism, and four or more conductive pins electrically connected to the control mechanism and extending into the power source receptacle. The system further includes a plurality of types of power sources, each of the types of power sources being removably receivable in the power source receptacle. At least some of the types of power sources have four or more points such that, when the power source is disposed in the power source receptacle, the four or more points contact corresponding ones of the four or more pins. A first one of the points is a positive terminal, a second one of the points is a ground terminal, and a thermistor is electrically connected between a third and a fourth one of the points. At least some of the types of power sources are of a first type of power source having a code. The code includes one of an electrical connection between the first and the fourth one of the points, an electrical connection between the second and the fourth one of the points, and no electrical connection to the fourth one of the points, such that the code identifies a power source as a particular type of the first type of power source. The control mechanism is programmable to read the code and identify a power source received in the power source receptacle as a particular type of the first type of power source. The control mechanism is programmable to automatically adjust internal programming of the electrical apparatus in response to identification of the particular type of the first type of power source.

In accordance with another aspect of the present invention, a power source is provided. The power source includes two or more batteries electrically connected to each other. The power source further includes a positive terminal, a ground terminal, a third and a fourth terminal, and a thermistor electrically connected between the third and the fourth terminal. The fourth terminal is one of electrically connected to one of the ground terminal and the positive terminal and electrically unconnected to both the ground terminal and the positive terminal.

In accordance with still another aspect of the present invention, a method for making a power source is provided. According to the method, a plurality of batteries are provided adjacent one another. The plurality of batteries are wrapped in a shrink wrap material. The shrink wrap material is heated so that the shrink wrap material conforms to a shape of the plurality of batteries.

BRIEF DESCRIPΉON OF THE DRAWINGS

The present invention can be further understood with reference to the following description in conjunction with the appended drawings, wherein like elements are provided with the same reference numerals. In the drawings:

FIGS. IA and IB are perspective top and bottom views, respectively, of battery packs according to an embodiment of the present invention;

FIG. 2 is a perspective view of a bottom side of an electrical apparatus showing the electrical apparatus with cover for a battery pack receptacle removed;

FIG. 3 is a cross-sectional side view of a battery pack inside of an electrical apparatus according to the present invention;

FIGS. 4A-4D are schematic views showing identification code schemes used in a battery pack according to an embodiment of the present invention;

FIG. 5 is an exploded perspective view of a battery pack according to an embodiment of the present invention, shown without a shrink wrap wrapper;

FIGS. 6A-6C are left side, top side, and right side plan views of a portion of a battery pack according to an embodiment of the present invention; and FIG. 7 is a block diagram showing a portion of a control mechanism according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a system for identifying a type of power source or battery pack 21 (FIGS. 1A-1B, 3, and 4) for an electrical apparatus 23 (FIGS. 2 and 3) such as a modem or a hand-held product. The electrical apparatus 23 has a battery pack receptacle or chamber 25 for receiving a plurality of types of physically similar battery packs 21. The electrical apparatus 23 further has intemal controls including a control mechanism 27' such as a microprocessor. The battery pack receptacle 25 is preferably configured to receive one type of power source 21 comprising one or more, preferably five, cylindrical single cell alkaline batteries, preferably so- called "AA" batteries, in a conventional manner, such as by providing a surface 26 of the battery pack receptacle that is shaped to conform to the shapes of the cylindrical batteries and has conventional electrical contacts and connections for electrically connecting the plurality of single cell alkaline batteries, e.g., in series. The terms power source and battery pack 21 is used generically in the present application to include physically interconnected, i.e., pre-packaged, and physically discrete batteries.

The battery pack receptacle 25 of the electrical apparatus 23 preferably further includes four or more conductive pins or terminals 29, 31, 33, 35 electrically connected to the control mechanism 27' and extending into the battery pack receptacle. As discussed below, the pins 29, 31, 33, 35 are preferably used to identify particular ones of a type of battery pack 21 other than a battery pack in the form of the above-mentioned, discrete, single cell alkaline batteries. The battery pack 21 is preferably removably receivable in the battery pack receptacle 25. A first type of battery pack 21 has four or more points or terminals 37, 39, 41, 43 for contacting the four or more pins or terminals 29, 31, 33, 35, respectively, when the battery pack is disposed in the battery pack receptacle. The pins 29, 31, 33, 35 are preferably spring mounted and, when the battery pack 21 is inserted into the battery pack receptacle 25, the springs of the pins are preferably compressed upon contact with the terminals 37, 39, 41, 43, respectively, to ensure good electrical contact and minimize the possibility of arcing and damage to the terminals.

A slot 45 is preferably provided in the battery pack proximate and a corresponding male member 47 is preferably provided in the battery pack receptacle 25 for being received in the slot to ensure proper alignment of the battery pack in the battery pack receptacle so that the pins 29, 31, 33, 35 are properly oriented relative to the respective points. The points 37, 39, 41, 43 and the slot 45 are preferably aligned in a space between two adjacent ones of the batteries, which are preferably cylindrical, so that the pins 29, 31, 33, 35 are only compressed when a battery pack 21 is used, and not when conventional, separate, single cell alkaline batteries are used.

When the battery pack 21 is of the type in which four or more points are provided, a first one of the points 37 is a positive terminal. A second one of the points 39 is a ground terminal. A third one of the points 41 is preferably a thermistor terminal. A fourth one of the points 43 is preferably used to identify the battery pack as being a particular type of the first type of battery pack. A thermistor 71 is preferably electrically connected between the third and the fourth points 41 and 43. Additional points, if provided, may be used for other functions, including identifying additional types of batteries.

As seen in FIGS. 4A-4C, in battery packs 21 of the type in which four or more points 37, 39, 41, 43 are provided, the battery pack is preferably coded, the code including one of an electrical connection between the first and the fourth one of the points, i.e., positive at the first and fourth, connected terminals, negative at the second terminal, and T, for thermistor, at the third or thermistor terminal, an electrical connection between the second and the fourth one of the points, i.e., negative at the second and fourth, connected terminals, positive at the first terminal, and T at the third or thermistor terminal, and no electrical connection to the fourth one of the points, i.e., positive at the first terminal, negative at the second terminal, T at the third or thermistor terminal, and no signal at the fourth terminal. In this manner, the code identifies a power source as a particular type of the first type of power source.

The control mechanism 27 ^L is programmed, or programmable, to read the code and identify a power source 21 received in the battery pack receptacle 25 as a particular type of the first type of power source, i.e., nickel- cadmium, nickel metal hydride, lithium, or some other type. The control mechanism 27' preferably automatically adjusts, or is programmable to automatically adjust, internal programming of the electrical apparatus 23 in response to identification of the particular type of the first type of power source. More particularly, the control mechanism 27' preferably adjusts programming such as that for detecting when the battery pack is fully, partially, or not charged, when an end of a charge is reached for a particular type of battery pack, etc. Thus, according to the present invention, it is possible to use multiple types of batteries or battery packs in a single electrical apparatus without the need for the user to drastically modify the preexisting circuitry because a determination of the type of battery pack and necessary adjustments to accommodate the particular type of battery pack are made automatically.

Where the battery pack 21 is in the form of conventional, discrete single cell alkaline batteries, the conventional electrical contacts and connections provided for such types of batteries are preferably used to power the electrical apparatus, and the pins 29, 31, 33, and 35 do not play a role the power supply of the electrical apparatus. The control mechanism 27' is preferably programmable, preferably programmed, to identify that conventional single cell batteries are being used, such as by detecting that power is provided from points other than the pins, or by detecting that a contact is not closed as a result of the non-compression of the pins, and to automatically adjust intemal programming of the electrical apparatus in response to identification of the second type of power source. Thus, a conventional power source 21 in the form of conventional, discrete single cell alkaline batteries exhibits a code, or the absence of a code, as seen in FIG. 4D, i.e., no signal from points at the first, second, third, and fourth pins.

A nickel cadmium battery pack having four points according to a preferred embodiment is seen in FIG. 5. In the battery pack 21, the fourth point 43, closest to the second or ground point 39, is preferably electrically connected to the second point, i.e., is grounded, while the third point 41 is not grounded. In other types of battery packs of the type having four points, a nickel metal hydride battery pack may, for example, be identified by a code wherein the fourth point is electrically connected to the first point, and a lithium battery pack is identified by a code wherein the fourth point is not connected to either the first point or the second point, or vice versa.

Preferably, additional types of battery packs 21 are identified in the electrical apparatus 23 by providing the battery packs usable in the electrical apparatus with additional points or terminals and by providing the electrical apparatus with a corresponding additional number of pins. For example, if another type of battery pack is provided, and five pins and points are provided, the battery pack may be identified by connecting a fifth point to one of the first point and the second point, or to neither the first or second point. Still further types of battery packs may be identified by some combination of connections or no connections, such as by connecting the fourth point to one of the first and the second point, or not connecting the fourth point to either the first or the second point, and by connecting the fifth point to one of the first and the second point, or not connecting the fifth point to either the first or the second point.

Different types of battery packs 21 of may also be identified by other techniques, such as by reversing the location of the third or thermistor terminal 41 and fourth terminal 43 to identify the battery pack as one of either a first or a second family of battery packs. As above, the fourth terminal 43, and additional points, if provided, is used in the manner to distinguish between particular types of battery packs within the particular family.

The batteries 49 in the battery pack 21 are preferably secured in position relative to each other in such a manner that the battery pack fits in the battery pack receptacle 25 having the shaped or contoured surface 26 used for holding a plurality of single cell alkaline batteries. The batteries 49 are preferably approximately the same length and diameter as conventional, commercially available single cell alkaline batteries and, accordingly, the manner in which the batteries are secured in position relative to each other preferably requires minimal space and permits the battery pack of multiple batteries to rest on the same contoured surface 26 as the single cell alkaline batteries. A preferred technique for securing the batteries 49 relative to one another is by bonding the batteries together with an adhesive 50 in a jig for holding the batteries in place relative to one another. The batteries 49 are then preferably at least partially surrounded with a shrink wrap material 51, preferably a shrink wrap material such as 0.1 mm polyolefin sheet, that may be provided in tubular form or provided in sheet form and formed into a tube. An adhesive material is preferably provided on an interior side of the tube or sheet of shrink wrap material 51 for bonding the material to the batteries 49 and other elements of the battery pack, which are discussed further below. The shrink wrap material 51 around the battery pack 21 is preferably slit, preferably by a laser slitting device, along the length of the battery cells in the regions between the batteries 49 on one "slit" side 53 of the battery pack, the other side 55 of the battery pack preferably being unslit. Preferably, two slits 57, 59 are provided. When the slit shrink wrap material 51 is heated, the shrink wrap material on the slit side 53 of the battery pack 21 shrinks to conform closely to the shape of the batteries 49, thereby securely holding or clamping the batteries 49 in position relative to each other and permitting the battery pack to rest on the same contoured surface 26 used for multiple single cell alkaline batteries, even in a hot ambient environment in which the shrink wrap material will tend to contract. The shrink wrap material 51 remains stable and close to the battery cells. The unslit shrink wrap material 51 on the other side 55 of the battery pack 21 shrinks to form a substantially flat surface.

A preferred embodiment of a nickel cadmium battery pack 21 is seen in an exploded view in FIG. 5. In this embodiment, the points are preferably defined by a positive terminal conductor 61, a thermistor terminal 63, and a negative terminal conductor 65. The positive terminal conductor 61 defines the first point 37, or positive terminal, the negative terminal conductor 65 defines the second point 39, or ground terminal, the thermistor terminal 63 defines the third point, and the negative terminal also defines the fourth point 43, i.e., the fourth point is electrically connected to the second point. However, if desired or necessary, sequences of terminals other than that shown may be provided to identify a particular battery and to provide a positive and a ground terminal.

A plastic base 67 having a recess 69 therein for receiving a thermistor 71 is preferably provided between two of the batteries 49. The slot 45 is preferably formed in the base 67. The positive terminal conductor 61, the thermistor conductor 63, and the negative terminal conductor 63 are bonded to the base 67 such that the thermistor connects the thermistor conductor and the negative conductor.

Temperature of the battery pack 21 is preferably detected and monitored with the thermistor 71 in a conventional manner, such as by periodically measuring the resistance of the thermistor between the third and fourth points 41 and 43 with the control mechanism 27'. Battery power levels may be determined as a function of temperature as determined by measuring resistance across the thermistor and converting the measured resistance to temperature or power signals with the microprocessor 105. One or more indicators 110, which may be in the form of one or more lights or displays, are preferably provided to indicate parameters such as battery temperature or power levels as determined by the microprocessor 105. Where a thermistor or similar temperature detection element is used in the battery pack 21, at least one terminal or point is disconnected from the power or positive terminal or point 37 and the ground terminal or point 39 and serves as the thermistor terminal. However, if desired or necessary, both the third and fourth terminals or points 41 and 43, as well as other points, if provided, may be arranged in one of a number of possible connections or non-connections between the third and fourth points and the first and second points 37 and 39 as a means of identifying a particular type of battery, without providing a thermistor.

As seen in FIGS. 5 and 6A-6C, the batteries 49 are preferably electrically connected to one another in series by a plurality of conductive strips 73, such as nickel strips. A thermal fuse 75 is preferably connected in series between two of the batteries 49 for interrupting a power supply from the battery pack 21 when the temperature of the battery pack rises above a predetermined temperature. Insulators 77 are preferably secured, e.g., with adhesive, over the strips 73 before positioning the positive and negative terminal conductors 61 and 65, respectively, over the insulators and surrounding the batteries 49 with the shrink wrap 51. An insulator 79 is preferably secured over the points 37, 39, 41, 43 and the slot 45. A label 81, such as a pull tab label, may be provided such that a tab of the label extends out from an open end of the shrink wrap 51. After shrinking the shrink wrap 51 around the batteries 49, the shrink wrap is preferably cut to expose the points 37, 39, 41, 43 and the slot 45.

The base 67, terminal and thermistor conductors, and other elements disposed between two of the batteries 49 cause the region 83 between those two batteries to be raised in relation to regions between other ones of the batteries, if provided. Accordingly, the portion 26' of the surface 26 in the battery pack receptacle 25 corresponding to the region 83 is preferably shaped differently, i.e., is flattened, than portions of the surface corresponding to regions between other ones of the batteries, if provided, which are preferably shaped to define portions of cylinders.

As seen in FIG. 7, the control mechanism 27' preferably includes an analog-to-digital converter 100 that receives input data from the terminals or pins 29, 31, 33, 35 relating to battery temperature and type. The control mechanism 27' preferably further includes a microprocessor 105. The analog- to-digital converter 100 converts the input data from the terminals or pins 29, 31, 33, 35 to information readable by the microprocessor 105, which then processes the information and determines which type of battery pack 21 is present in the battery pack receptacle 25 and the power level of the battery pack.

If desired, instead of providing multiple individual terminal conductors 61, 65, thermistor conductors 63, and strips 73 for electrically connecting the batteries 49, all or some of those components may be formed as printed circuit, preferably on an insulative, flexible substrate.

In a method for making the battery pack 21, two or more, preferably five, batteries are positioned adjacent one another, preferably side by side. The batteries 49 are wrapped in the shrink wrap material 51 that is preferably in tubular form. The shrink wrap material 51 is heated so that the shrink wrap material conforms to a shape of the plurality of batteries. Preferably, one or more slits 57, 59 are formed in the shrink wrap material 51 in regions between at least some of the batteries 49. The batteries are preferably electrically connected to one another by conductive strips 73 or by printed circuitry including conductive strips. Ground and power terminals 39 and 37 are preferably disposed in at least one of the regions 83 between at least two of the plurality of batteries.

It is, of course, possible to embody the present invention in specific forms other than those described above without departing from the spirit of the present invention. The embodiments shown are merely illustrative and should not be considered to be restrictive in any way. The scope of the present invention is given in the appended claims, rather than in the preceding description, and all variations and equivalents which fall within the range of the claims are intended to be embraced therein.

Claims

WHAT IS CLAIMED IS:

1. A system for identifying a power source as a particular type of power source of a plurality of types of power sources usable with an electrical apparatus, comprising: an electrical apparatus having a power source receptacle, a control mechanism, and four or more conductive pins electrically connected to the control mechanism and extending into the power source receptacle; a plurality of types of power sources, each of the types of power sources being removably receivable in the power source receptacle, at least some of the types of power sources having four or more points such that, when the power source is disposed in the power source receptacle, the four or more points contact corresponding ones of the four or more pins, a first one of the points being a positive terminal, a second one of the points being a ground terminal, and a thermistor being electrically connected between a third and a fourth one of the points; at least some of the types of power sources being of a first type of power source having a code, the code including one of an electrical connection between the first and the fourth one of the points, an electrical connection between the second and the fourth one of the points, and no electrical connection to the fourth one of the points, such that the code identifies a power source as a particular type of the first type of power source; and the control mechanism being programmable to read the code and identify a power source received in the power source receptacle as a particular type of the first type of power source, the control mechanism being programmable to automatically adjust intemal programming of the electrical apparatus in response to identification of the particular type of the first type of power source.

2. The system as set forth in Claim 1, wherein a second type of power source has no points for contacting the four or more pins in the electrical apparatus, the control mechanism being programmable to detect the presence of the second type of power source and to automatically adjust intemal programming of the electrical apparatus in response to identification of the second type of power source.

3. The system as set forth in Claim 1, wherein the power source includes two or more batteries electrically connected to each other.

4. The system as set forth in Claim 3, wherein the power source includes means for securing the batteries relative to each other.

5. The system as set forth in Claim 4, wherein the securing means includes a shrink wrap material at least partially surrounding the batteries.

6. The system as set forth in Claim 5, wherein the batteries are substantially cylindrical and the shrink wrap material includes one or more slits between the batteries such that, when the shrink wrap material is heated, a portion of the shrink wrap material proximate the slits conforms to contours of the batteries.

7. The system as set forth in Claim 6, wherein the power source receptacle includes a surface having contours corresponding to contours of the batteries.

8. The system as set forth in Claim 6, wherein the four or more points are disposed between two of the batteries.

9. The system as set forth in Claim 6, wherein the shrink wrap material includes two slits between the batteries.

10. The system as set forth in Claim 6, wherein the slits in the shrink wrap material are provided only on one side of the power source.

11. The system as set forth in Claim 1, wherein power sources of the first type of power source have four points.

12. The system as set forth in Claim 1, further comprising means for interrupting a power supply from the power source when a temperature of the power source rises above a predetermined temperature.

13. A power source, comprising: two or more batteries electrically connected to each other; a positive terminal; a ground terminal; a third and a fourth terminal; and a thermistor electrically connected between the third and the fourth terminal; wherein the fourth terminal is one of electrically connected to one of the ground terminal and the positive terminal and electrically unconnected to both the ground terminal and the positive terminal.

14. The power source as set forth in Claim 13, further comprising means for securing the batteries relative to each other.

15. The power source as set forth in Claim 14, wherein the securing means includes a shrink wrap material at least partially surrounding the batteries.

16. The power source as set forth in Claim 15, wherein the batteries are substantially cylindrical and the shrink wrap material includes one or more slits between the batteries such that, when the shrink wrap material is heated, a portion of the shrink wrap material proximate the slits conforms to contours of the batteries.

17. The power source as set forth in Claim 16, wherein each of the terminals is disposed between two of the batteries.

18. The power source as set forth in Claim 16, wherein the shrink wrap material includes two slits between the batteries.

19. The power source as set forth in Claim 16, wherein the slits in the shrink wrap material are provided only on one side of the power source.

20. The power source as set forth in Claim 13, further comprising means for intermpting a power supply from the power source when a temperature of the power source rises above a predetermined temperature.

21. A method for making a power source, comprising the steps of: positioning a plurality of batteries adjacent one another; wrapping the plurality of batteries in a shrink wrap material; and heating the shrink wrap material so that the shrink wrap material conforms to a shape of the plurality of batteries.

22. The method as set forth in Claim 21, comprising the further step of: forming one or more slits in the shrink wrap material in regions between at least some of the plurality of batteries.

23. The method as set forth in Claim 21, comprising the further step of electrically connecting the plurality of batteries to one another.

24. The method as set forth in Claim 23, comprising the further i step of providing ground and power terminals in at least one of the regions between at least two of the plurality of batteries.