AU742989B2

AU742989B2 - Battery pack incorporating battery pack contact assembly

Info

Publication number: AU742989B2
Application number: AU50514/00A
Authority: AU
Inventors: Gregory S. Patterson
Original assignee: Ericsson Inc
Current assignee: Ericsson Inc
Priority date: 1996-08-15
Filing date: 2000-08-03
Publication date: 2002-01-17
Anticipated expiration: 2017-08-13
Also published as: AU5051400A

Description

P/00/011 28/5/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: BATTERY PACK INCORPORATING BATTERY PACK CONTACT ASSEMBLY The following statement is a full description of this invention, including the best method of performing it'known to us BATTERY PACK INCORPORATING BATTERY PACK CONTACT ASSEMBLY

BACKGROUND

The present invention relates generally to a power supply for a mobile communications device or the like and, more particularly, to a battery pack utilising a battery pack contact assembly including a carrier supporting selectively plated contacts and a method of manufacturing a battery pack.

A power supply such as a battery pack typically accounts for a substantial portion of a portable communications device's physical volume. Minimising this physical volume is an important advancement in mobile communications development. Typically, the gold-plated contact points are used to provide good Si electrical contact between the battery pack and the portable transceiver. In the past, a typical battery pack would comprise a plurality of cells grouped as shown in FIGURE 1. Interconnection among the cells is achieved by means of welded nickel straps. The battery pack itself carries two torsional springs having 15 gold-plated tips for interconnecting the pack to the transceiver. With this approach, the presence of the springs and the straps within the battery pack contribute unnecessary physical bulk and manufacturing cost.

As an alternative to this design, the springs may be moved from the' battery pack to the body of the communications device. With this approach, the springs contact the exposed terminal poles of two of the battery pack's cells as shown in :i FIGURE 2. To ensure good contact, the poles of the cells are provided with gold S plating. Because only two of the cells need plating, however, three kinds of cells are then required to be manufactured. This is, cells without gold plating, cells with gold-plated negative poles, and cells with gold-plated positive poles all must be provided.

Because of this requirement for three types of cells, the assembly of these cells into a battery pack incurs unneeded inventory control and article manipulation problems. Moreover, because of the realties of the manufacture of the cells, three cell assembly lines must be established to make the three types of cells, because the plating of the cell poles must be done early in the cell manufacturing process.

Any discussion of documents, devices, acts or knowledge in this A 7Q specification is included to explain the context of the invention. It should not be 2 taken as an admission that any of the material formed part of the prior art base or the common general knowledge in the relevant art in Australia on or before the priority date of the claims herein.

SUMMARY OF THE INVENTION In one aspect, the present invention provides a battery pack contact assembly including: a carrier formed of a conducting weldable material; a first contact integral with said carrier, said first contact having an exposed weldable surface and a selectively plated surface; and a score line between said carrier and said first contact.

In one embodiment, the carrier and the contact may be substantially L-shaped, wherein the carrier forms a first leg of the L-shape and the contact forms a second leg of the L-shape. The selectively plated surface may be disposed at a distal end of the second leg and be substantially parallel with the first leg. In an alternative embodiment, the carrier and the contact are oc 15 substantially T-shaped wherein the carrier forms a base of the T-shape and the contact forms a cross member of the T-shape. In this regard, the selectively i plated surface maybe disposed substantially perpendicular to the base across an outmost section of the cross member. In yet another embodiment, the exposed weldable surface and the selectively plated surface are bent at substantially a 900 angle.

"Comprises/comprising" when used in this specification is taken to specify Sthe presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS These and other aspect and advantages of the present invention will be described in detail with reference to the accompanying drawings, in which: FIGURE 1 illustrates a battery pack having a conventional structure; FIGURE 2 illustrates an alternative conventional battery pack arrangement; FIGURE 3 illustrates a battery pack according to the present invention; FIGURE 4 is a plan view of the battery pack shown in FIGURE 3 before the carrier of the contact assembly is removed; FIGURE 5A illustrates an alternative arrangement of the contact assembly; FIGURE 5B illustrates another alternative arrangement of the contact assembly; and FIGURE 6 illustrates still another alternative of the contact assembly.

S: DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS is FIGURE 3 shows the arrangement of battery cells within the battery pack according to the present invention. The battery pack is shown with four battery cells for example purposes only. Those of ordinary skill in the art will understand that different numbers of battery cells would be suitable for the S-features of the present invention, and the invention is not meant to be limited to four battery cells.

The battery cells 12 are disposed adjacent one another and connected in series defining a positive terminal pole 14 and a negative terminal pole 16. The positive and negative terminal poles 14, 16 are adapted to contact leads of a device powered by the battery pack, such as a mobile communications device (not shown).

As shown in FIGURE 3, the battery cells are aligned in a pattern such that a negative pole of one battery cell is disposed adjacent and electrically connected to a positive pole of an adjacent battery cell, with the exception of the positive and negative terminal poles 14, 16.

In order to assure good contact between the terminal poles 14, 16 and the S contact leads of the battery pack powered device, it is desirable to utilize gold or gold-plated contacts. In the past, however, it has been difficult to secure gold or gold plated contacts to the terminal poles 14, 16 for contact with the device leads.

In accordance with the present invention referring to FIGURE 4, a battery pack contact assembly 20 is utilized to secure selectively plated contacts to the terminal poles 14, 16 of the battery train. The contact assembly 20 includes a carrier 22, a first contact 24 integral with the carrier 22, and a second contact 26 integral with the carrier 22. The contact assembly 20 is preferably stamped from S a metal sheet such as nickel. Score lines 28 are provided between the carrier 22 and the first and second contacts 24, 26, respectively. The contacts 24, 26 are selectively plated with, for example, gold to define a selectively plated surface .r and an exposed weldable surface 32 on each contact 24, 26. The selectively plated surfaces are plated in a conventional manner.

The size of the contacts 24, 26 and the area of selective plating are determined relative to the diameter of the cells used in the battery pack and the terminal pitch of the mating connector in the phone. The contact which represents the positive terminal pole must allow enough non-plated surface for welding to the smaller cap. In addition, the overall contact size must be designed such that it does not come in contact with the adjacent cell negative end, since there is no insulator to prevent short circuit. The contact which represents the negative terminal pole must also allow enough non-plated surface for welding, while positioning the selectively plated surface properly with respect to the positive contact. The result is that the positive and negative contacts selective plated surfaces are separated by a distance equal to the mating battery connector terminal pitch (or spacing) in the phone.

During assembly, the carrier 22 is used to support the contacts 24, 26 in the vicinity of the terminal poles 14, 16, and the exposed weldable surfaces 32 of the contacts 24, 26 are welded to respective terminal poles 14, 16. The carrier 22 is then fatigued along the score lines 28 and removed from the assembly. The resulting contacts are securely welded to the terminal poles 14, 16 and provide a gold-plated surface for contact with the leads of the battery pack powered device.

1o SFIGURES 5A and 5B illustrate alternative embodiments of the contact assembly according to the present invention. In FIGURE 5A, the carrier 22' and a single contact 24' integral therewith are substantially L-shaped, wherein the carrier 22' forms a first leg of the L-shape, and the contact 24' forms a second leg of the L-shape. The contact 24' similarly includes an exposed weldable surface 32"and a selectively plated surface 30'. The selectively plated surface 30' is disposed at a distal end of the second leg and is oriented substantially parallel with the first leg. A score line 28' is provided between the carrier 22' and the contact 24'.

In FIGURE 5B, the carrier 22" and the contact 24" are substantially Tshaped, wherein the carrier 22" forms a base of the T-shape and the contact 24" forms a cross member of the T-shape. The contact 24" similarly includes an exposed weldable surface 32" and a selectively plated surface 30". In this embodiment, the selectively plated surface 30" is disposed substantially perpendicular to the base across an outermost section of the T-shape cross member.

SAs still another alternative (not shown), the cell alignment of FIGURE 2 may be used with the battery pack contact assembly according to the invention.

In this arrangement, the contact assembly 20 would be shaped similar to that illustrated in FIGURE 4, however, the carrier 22 would be longer to position the s contacts 24, 26 adjacent the outermost cells corresponding to the positive and negative terminal poles.

In order to provide access from an alternate surface of the battery pack, 4* the exposed weldable surface 32 and the selectively plated surface 30 may be bent at substantially a 90* angle as shown in FIGURE 6.

S:By virtue of the structure according to the present invention, a battery pack for a mobile communications device or the like can be made smaller while ensuring a good electrical contact with the device. The use of the battery pack.

1s contact assembly eliminates inventory control and article manipulation problems.

Moreover, manufacturing of the battery packs is made easier as the cells in the battery packs can be manufactured in a single assembly line.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

"Ccmprises/cnprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, conponents or groups thereof.

Claims

1. A battery pack contact assembly including: a carrier formed of a conducting weldable material; a first contact integral with said carrier, said first contact having an exposed weldable surface and a selectively plated surface; and a score line between said carrier and said first contact.

2. An assembly according to claim 1, wherein said carrier and said contact are substantially L-shaped, said carrier forming a first leg of the L-shape and said contact forming a second leg of the L-shape. oe 9

3. An assembly according to claim 2, wherein said selectively plated surface is disposed substantially parallel with said first leg at a distal end of said second leg.

4. An assembly according to claim 1, wherein said carrier and said contact are substantially T-shaped, said carrier forming a base of the T-shape and said contact forming a cross member of the T-shape.

5. An assembly according to claim 4, wherein said selectively plated surface is disposed substantially perpendicular to said base across an outermost section of the cross member.

6. An assembly according to any one of the proceeding claims, wherein said exposed weldable surface and said selectively plated surface are bent at substantially a 900 angle.

7. A battery pack assembly as claimed in claim 1, substantially as herein described with reference to figures 3 to 6 of the accompanying drawings. DATED this 9 TH day of November 2001 ERICSSON INC WATERMARK PATENT TRADEMARK ATTORNEYS 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA RCS/NWM/GLM *0* 0 .:.005 *S fr