GB2159660A

GB2159660A - Electric storage batteries

Info

Publication number: GB2159660A
Application number: GB08413759A
Authority: GB
Inventors: Leslie Kenneth Fisher; John Ernest Treweek
Original assignee: Chloride Group Ltd
Current assignee: Chloride Group Ltd
Priority date: 1984-05-30
Filing date: 1984-05-30
Publication date: 1985-12-04
Also published as: GB8413759D0; GB2159660B

Abstract

An electric storage battery includes an outer container of insulating material from the lid 2 of which an upstanding battery terminal extends. The terminal is connected to a terminal post 22 within the container by means of a conductive terminal strap which extends transverse to the direction in which the terminal extends over the outer surface of the lid. The terminal comprises conductive material 14 extending around a core of insulating material 4 which is integral with the material of the lid. <IMAGE>

Description

SPECIFICATION Electric storage batteries The present invention relates to electric#sto- rage batteries, in particular of lead acid type and is particularly concerned with the terminals of such batteries.

In lead acid batteries the plates are generally connected to the terminals by terminal pillars which are connected to a respective plate strap in the two electrical end cells of the battery. The connection to the plates is effected by the plate straps which are cast around or otherwise connected to lugs projecting upwardly from the plates. The plate straps in each cell are spaced apart to ensure that they can not contact one another and this results in the lugs of lead acid battery plates generally being offset from the centre of the plates.This in turn results in the terminal pillars being offset from the central plane of the battery and since the terminal pillars are generally in line with the terminals to which they are connected the terminals are generally assymmetrically disposed on a wall, generally the lid, of the battery container, typically at or adjacent respective corners of the lid. Lead acid batteries, in particular of automotive type, are thus generally "handed" and it can therefore be necessary for manufacturers to produce automotive; batteries which differ only in their "handedness" that is to say their terminals have been moved to different corners of the lid or are of reversed polarities, to enable the batteries to be fitted to cars with differently disposed trailing terminal connectors.

The trailing terminal connectors on some cars require terminals on the lid of the battery while others require terminals on a side wall of the battery and this adds further to the range of automotive batteries which must be manufactured and which differ only in their terminal configuration.

British Patent Specification No. 21 22020A discloses an automotive battery whose construction permits it to be fitted to cars with differing types and differing "handedness" of the trailing terminal connectors. To this end the battery has two terminals on a sidewall and two terminals on the lid, which latter terminals are disposed on the centre line of the lid, whereby the battery is not "handed" as regard the top terminals. However, since the terminal pillars, or at least the plate straps to which these pillars are connected, are of necessity offset from the centre line of the battery, horizontal straps must be provided between the terminal pillars and the associated terminals.These straps are of lead or lead alloy and of relatively massive construction to minimise their electrical resistance and carry the required current and therefore add significantly to the weight and expense of the battery. The same applies also to a lead acid battery with conventional terminals and it is an object of the present invention to reduce the amount of metal in the terminals and terminal straps.

The terminal straps may extend beneath the lid in which event they may extend from the plate straps to which they are connected and the terminal pillars may project upwardly from them in line with the terminals to which they are connected. Alternatively, the terminal straps may extend above the lid in which event the terminal pillars may project straight up from the associated plate straps. The latter possibility is to be preferred in the case of a battery in which both side and top terminals are provided since it will mean that each polarity of the battery is associated with only one hole in the lid which must be sealed, as may be seen from a comparison of Figures 2 and 4 of the prior patent referred to above.

However, in this case the terminals are retained in position only by the associated terminal straps and are therefore subject to damage since the terminal straps are inherently relatively weak in bending. Accordingly it is a further object of the present invention to provide a battery in which the terminals may be connected to the associated terminal pillars by a terminal strap extending above the battery lid but in which the terminals are nevertheless reliably retained in position and are thus not subject to damage.

According to the present invention an electric storage battery includes an outer container of insulating material from one wall of which a battery terminal extends, the terminal being connected to a terminal post within the container, the terminal comprising conductive material extending around a core of insulating material, e.g. integral with the material of the said wall. Thus in the battery in accordance with the present invention the terminals are not solid metal, i.e. lead or lead alloy in the case of lead acid battery, as is conventional but instead comprise a conductive shell extending around a core of insulating, e.g. plastics, material which is integral with the material of the wall, e.g. the lid and is moulded at the same time as that wall.The terminals thus comprise less conductive material, typically lead or lead alloy, than would otherwise be the case which therefore results in a saving not only in cost but also in weight of the battery.

In the preferred embodiment the terminal is connected to a terminal post within the container by a conductive terminal strap which extends transverse to the direction in which the terminal extends. Thus in this embodiment the terminal is offset from the terminal post to which it is connected rather than colinear with it as is common.

The terminal strap may extend over the outer surface of the said wall, e.g. the lid, and integral with a boss portion which passes through the said wall and to which the terminal post is connected. In additional to terminals extending through the lid the battery may also have terminals in a side wall and these terminals may also be connected to the boss portions by further respective terminal straps.

In one embodiment the conductive material does not extend over the full area of the end of the terminal and the core of insulating material has a hole formed therein adapted to receive a threaded connector on a trailing terminal connector. Thus the screw which is commonly provided on automotive trailing connectors is screwed into the hole in the insulating material rather than into the conductive material which provides a more secure and long lasting connection whilst the electrical connection is made with the outer conductive material with which the trailing connector is drawn into contact by the pressure exerted by the screw.

It is preferred that one of the opposed surfaces of the core and the surrounding conductive material has one or more recesses therein into which the material of the other extends. This positive interlocking of the core and the conductive material results in the conductive material being firmly keyed to the battery container and the terminal is thus not subject to distortion or damage. The conductive material of the terminal, the terminal strap and boss portion preferably constitute a single preformed unit around which the battery container, or the lid thereof, is moulded and thus for practical reasons connected with the casting of this integral unit it is preferred that the surrounding conductive material of the terminal has one or more projections, e.g.

a rib, which extend into the core.

Further features and details of the present invention will be apparent from the following description of one specific embodiment which is given by way of example only with reference to the accompanying drawing which is a scrap sectional elevation through the lid of a lead acid automotive battery prior to being secured to the battery container.

The construction of the battery is generally similar to that of British Patent Specification No. 21 22020A, the disclosure of which is incorporated herein by reference, and will therefore not be described in detail. The battery has two terminals projecting from its lid but, in this embodiment, no side terminals. At each end the lid, which is of injection moulded plastics material, has a planar portion 2 upstanding from which is an integral circular section spigot or core 4. Adjacent the planar portion 2 is a hole which is surrounded by a peripheral, depending, ribbed flange 6.

The lid is moulded around two preformed, integral terminal inserts of lead or lead alloy, each of which comprises a boss portion 8 which is retained and sealed within the flange 6 by the ribs, is provided with a central aperture 10 and is integrally connected by means of a horizontal terminal strap 12 contacting the lid to a terminal portion 14 which extends around the peripheral surface but not the end surface of the plastics core 4. The lower portion of the terminal portion 14 is engaged on the side remote from the boss portion 8 by an upstanding part-annular rib 16. The plastics core 4 is provided with a blind central bore 18 which is open at the free end of the core.Adjacent the lid the core is of reduced area, in this case an undercut portion, formed by a rib 20 on the terminal portion 14 around which plastics material flows during moulding thereby securely anchoring the terminal portion 14 to the lid. The core 2 is preferably of non-circular section, and in this case is provided with a plurality of flats 5 on its outer surface, to prevent relative rotation of the core 4 and the surrounding metallic terminal portion 14.

During assembly of the battery the lid is placed on the battery container and the terminal pillars 22 which project upwardly from the plate straps 24 extend into the openings 10.

The terminal pillars are then connected to the boss portions of the terminal inserts by the application of heat and the addition of further lead alloy 26 which subsequently solidifies in position.

By virtue of the fact that the upstanding terminals constitute a plastics core surrounded by lead alloy they are much lighter than if they were solid metal but their electrical function is unaffected. The terminal inserts are reliably secured in position by their engagement with the ribbed boss portion 8 and by the downwardly directed shoulder on the core 4 and by the flange 16.

Annular trailing terminal connectors may be connected to the terminals in the usual manner as may conventional cap-type trailing automotive connectors with a central screw, and in the latter case the screw is preferably selftapping and taps the bore 8 on its first insertion.

Claims

1. An electric storage battery including an outer container of insulating material from one wall of which a battery terminal extends, the terminal being connected to a terminal post within the container, the terminal comprising conductive material extending around a core of insulating material.

2. A battery as claimed in claim 1 in which the terminal is connected to a terminal post within the container by a conductive terminal strap which extends transverse to the direction in which the terminal extends.

3. A battery as claimed in claim 2 in which the terminal strap extends over the outer surface of the said wall and is integral with a boss portion which passes through the said wall and to which the terminal post is connected.

4. A battery as claimed in any one of the preceding claims in which the conductive material does not extend over the full area of the end of the terminal and the core of insulating material has a hole formed therein adapted to receive a threaded connector on a trailing terminal connector.

5. A battery as claimed in any one of the preceding claims in which the core of insulating material is integral with the material of the said wall.

6. A battery as claimed in any one of the preceding claims in which one of opposed surfaces of the core and the surrounding conductive material has one or more recesses therein into which the material of the other extends.

7. A battery as claimed in any one of the preceding claims in which the container includes a lid which is connected thereto, the lid constituting the said wall.

8. An electric storage battery substantially as specifically herein described with reference to the accompanying drawings.