GB2044983A

GB2044983A - Modular battery

Info

Publication number: GB2044983A
Application number: GB8009462A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-03-22
Filing date: 1980-03-20
Publication date: 1980-10-22
Also published as: AU5656580A; JPS5663769A; DE3010555A1

Abstract

A battery cell module (10) comprises a battery cell having an outer case (11, 12, 13, 14) and terminals (16, 17) accessible from outside the case whereby the cell is electrically connectable to an external circuit. The outer case comprises key formations (14, 15) by means of which a plurality of the modules (10) can be held in place in a housing by interengagement of the key formations (14, 15) with further key formations of the housing. <IMAGE>

Description

SPECIFICATION Modular battery This invention relates to a storage battery having replaceable cell modules.

Storage batteries are widely used in automotive, aviation and industrial applications. While the advantages of the battery the subject of the present specification are described primarily in terms of its use as a car battery, they would equally be obtained when the battery is used for other purposes.

Storage batteries usually consist of a number of cells connected in series. Prior to the advent of multi-cell batteries of unitary construction, a number of separate individual cells each with one positive and one negative terminal were grouped together in a box and connected, usually in series, to constitute a battery. With such batteries, care was required to ensure the correct inter-connection of cells, connecting leads and intercell terminals frequently corroded and failed and the cells were particularly susceptible to damage by mechanical vibration. One solution to these problems was development of the multi-cell battery of unitary construction now in general use.

A conventional multi-cell car storage battery has a case divided internally into separate compartments, each constituting a cell. Each compartment contains anode and cathode plates and electrolyte. The cells are connected in series by jumpers integrally connecting the anode of one cell to the cathode of the next. Characteristically, the construction is such that the whole assembly is sealed except for gas vents and removable plugs provided to top up electrolyte in each cell.

By virtue of their unitary construction, car batteries may be rendered useless when a fault develops in any one part of the battery. Frequently one cell develops an internal fault thereby necessitating costly replacement of the whole battery. Since the battery may typically contain six cells, five functioning cells are wasted in such replacement or the battery has to be returned to the factory and, in effect, rebuilt.

Not only because of relatively long average intervals between failures but also because of the size, weight and cost of multi-cell batteries few motorists carry a spare battery in their car and so battery failure can immobilize a vehicle and cause considerable inconvenience.

Furthermore by virtue that in multi-cell batteries of unitary construction the cells are inter-connected internally in the event of a faulty intercell connection there is a possibility of a spark igniting gases within the battery case resulting in an explosion.

An object of the present invention is a battery made up of individual cell modules in which: I. Individual cell modules can be easily removed and replaced in the event of a cell failure without need to replace the whole battery.

II. Each individual cell module is held firmly in place so as to be relatively resistant to vibra tion.

In preferred embodiments it is also desirable that: 1. It should be difficult, if not impossible, inadvertently to inter-connect the cell modules incorrectly.

2. The inter-connections between cell modules be robust, durable and simple to connect and disconnect.

3. The battery as a whole be enclosed for protection but that means be provided for external circuit connection to the positive and negative terminals of the series and for the topping up with electrolyte of each cell module.

According to a first aspect the invention consists in a battery cell module comprising: a battery cell having an outer case and terminal means accessible from outside said case whereby said battery cell is electrically connectable to an external circuit, said cell module being characterized in that a first key formation projects from and/or is recessed into said outer case.

Embodiments of the invention will now be described with reference to the accompanying drawings.

Figure 1 is an isometric view of one embodiment of a cell module according to the invention.

Figure 2 is an isometric view of another embodiment of a cell module according to the invention.

Figure 3 shows in plan a third embodiment of the invention.

Figure 4 shows the embodiment of Figure 3 in elevation.

Figure 5shows an embodiment of a terminal for use with embodiments of the invention.

With reference to Figure 1 there is illustrated a first embodiment of a battery cell module according to the invention.

The battery cell module indicated generally at 10 has an outer case for containing an electric battery cell which in the present example comprises the plates and electrolyte (not visible in the drawings) constituting a wet cell. The outer case comprises a roof 12, side walls 13, end walls 11 and a floor. A key formation is recessed into the end walls 11 of the outer case. In the embodiment illustrated in Figure 1 the key formation comprises one keyway slot 14 recessed into one end wall 11 of the outer case and a pair 15 of parallel keyway slots recessed into the opposite end wall of the outer case. Key way slots 14 and slot pair 15 each extend from the roof to the floor of the outer case and are open at the slot ends.

The module further comprises a positive terminal 16 and a negative terminal 17, each electrically connected to a group of plates within the cell module, and disposed on roof 12 of the cell module outer case and projecting upwardly therefrom and filling means 18 fitted with a removable closure for topping up the electrolyte of the cell from time-totime.

With reference to Figures 3 and 4 there is shown a housing, indicated generally at 20, adapted to hold a plurality of battery cell modules 10 of the type depicted in Figure 1.

Six cell modules 10 are shown held in housing 20 in the example illustrated in Figure 2.

Housing 20 comprises two side walls 21, two end walls 22 and a floor. Cell modules 10 are held in place in housing 20 by means of key formations 24 and 25 of housing 20 which project from the interior side walls 21 of housing 20 and inter-engage with key formations 14 and 15 of cell modules 10. In the example shown in Figure 3 the key formations of housing 20 comprise projecting keys 24 adapted to inter-engage keyway slots 14 of cell modules 10 and pairs 25 of projecting keys adapted to engage keywaysiotpairsl5ofcellmodules 10.

Each battery cell module 10 may be removed from housing 20 by sliding it upwardly until keys 24 and 25 disengage from keyway slots 14 and 15 whereupon it may be removed from the open top of housing 20 and, conversely, may be inserted in case 20 by engaging keys 24 and 25 with slots 14 and 15 of the cell module and pushing it downwardly.

Vibrational movement of cell modules 10 relative to housing 20 is prevented by inter-engagement of keys 24 and 25 with slots 14 and 15.

In the present example each cell module 10 has its positive terminal 16 adjacent the slot pair 15 and its negative terminal adjacent the single slot 14.

Keys 24 and 25 are disposed on the interior of the walls of housing 20 so that a cell module can be inserted only at six locations and so that a cell module can be inserted only in one orientation at each of the six locations. Furthermore the arrangement of keys 24 and 25 is such that alternate adjacent cells must be inserted in an orientation which results in the terminal of one polarity of one module being adjacent the terminal of opposite polarity of an adjacent module. This arrangement facilitates correct inter-connection of cell modules.

In a preferred embodiment the walls of the cell module outer case are moulded from polypropylene and housing 20 may also be moulded from polypropylene, the key slots and keyways respectively being formed during moulding.

The cell module outer case and housing may also be made from other materials although use of corrosion resistant materials is highly preferred.

In manufacturing the cell, the battery plates may for example be mounted to a module lid and electrically connected to their respective terminals also mounted on the lid. The lid and plate assembly is then positioned on the outer case with the plates interior of the outer case and joined to the walls of the outer case, for example by seam welding to provide the roof 12 of cell module 10. The cell may then be filled with electrolyte via filling means 18.

With reference to Figure 2 there is shown another embodiment of a cell module according to the invention.

Numerals used to identify parts of the cell module of Figure 1 are used to identify corresponding parts of the cell module of Figure 2.

The cell module of Figure 2 has additional key formations 30 and 31. Key formation 30 is a slot similar to slot 14 of the embodiment of Figure 1 and disposed on a third side wall of the module outer case while key 31 is a key projecting from the fourth wall.

A plurality of cell modules according to the embodiment of Figure 2 may be inter-engaged in a linear array by engaging a key 31 of one cell with the slot 30 of an adjacent-like cell module.

It will be apparent from the foregoing that the key formations of cell modules according to the invention may take a great variety of forms.

For example cell modules may have a slot on one wall and a projecting key on the opposite wall, or may have projecting keys on two opposite walls, and may have single or a plurality of recesses or projections, inter-engageable keys of housing 20 being modified accordingly.

As a further example, a cell module may have a keyway slot on one wall having a dovetail crosssection and a projecting key formation on an opposite wall having a corresponding dovetail crosssection. If the slot is closed at its upper end, it is then possible to connect together a plurality of like modules in interlocking engagement one with another and a separate housing to hold the plurality assembled together is not needed.

Cell modules according to the invention may be provided with conventional gas venting means (not illustrated in the drawings). Various means may be used to inter-connect cell modules electrically and it is desirable that the inter-connection contribute to the mechanical rigidity of an assembly of cell modules.

For example as shown in Figure 5 a rigid connecting stud 41 may be adapted to pass through a hole 40 bored through a terminal 16A of one cell, the other end of the bolt (not shown) passing through a hole bored through an adjacent terminal of opposite polarity of an adjacent cell whereby the cells may be connected in series and mechanically bolted by nuts 42 one to the other.

For preference the outer housing 20 illustrated in Figures 3 and 4 may be fitted with a removable lid (not shown in the drawings) which seals the housing. In this event the lid may be adapted to allow filler spouts extending upwardly from each module to be accessed thus permitting topping up of electrolyte without need for removal of the lid. Such a lid may also serve to prevent short circuiting across intercell connections as well as to keep the roof of the modules and sub-assemblies thereon free from external contamination.

The cell module terminals 16 and 17 may be terminal posts which are drilled and threaded so that a terminal external of the lid and having a threaded stub may have the stub inserted through an aperture in the lid and be screwed into the internal terminal post. Provided the diameter of the external terminal post is largerthan the aperture in the lid this arrangement also serves to hold the lid in place and has the advantage that terminal posts of the cell modules may have a low profile thus reducing the variety of replacement cell modules required.

In either case a washer for example of felt may be inserted between the outer terminal post and the lid to seal against acid seepage.

Alternatively external connection may be made using sockets connected to a lead through an aperture in the lid or by means of a terminal adaptor, one end of which is a socket adapted to connect with a terminal block of a cell and the other end of which protrudes through an aperture in the lid to provide a terminal post exterior of the box.

As will be apparent, batteries according to the invention have the advantage that the individual cells thereof are held firmly in place and are therefore not susceptible to damage as a result of vibration relative to the case. Individual cell modules may easily be inserted and removed so that in the event of the failure of any one cell that cell can be replaced without the need to replace the whole battery. It is a simple matter to insert and connect a new cell and it is impossible inadvertently to interconnect the cell modules incorrectly. The battery as a whole is well protected and is easily connected into external circuits as well as being easy to maintain.

Because the size of one cell is typically approximately one-sixth of the size of a conventional six-cell 12-volt car battery, it is perfectly feasible for a motorist to carry a spare cell in the car in a dry charged state together with electrolyte in a separate container and simply to effect replacement of a module in the event of a cell failure.

The inter-engaging key formations may take a variety of forms and are not restricted to single and double keys interengeable with single or double slots and other forms of terminal and connection thereto are within the scope of the invention.

Claims

1. A battery cell module comprising: a a battery cell having an outer case and terminal means accessible from outside said case whereby said battery cell is electrically connectable to an external circuit, said cell module being characterized in that a first key formation projects from and/or is recessed into said outer case.

2. A cell module according to Claim 1 in combination with a housing adapted to hold said cell module, said housing having a second key formation inter-engageable with said first key formation.

3. A cell module according to Claim 1, in combination with a battery having a second key formation inter-engageable with said first key formation.

4. A plurality of cell modules each according to Claim 1 wherein at least one cell module further comprises a second key formation inter-engageable with the first key formation of at least one other cell module.

5. A plurality of cell modules according to Claim 4wherein said at least one cell module further comprises another key formation inter-engageable with a key formation of a housing adapted to hold said plurality of cell modules.

6. The invention according to Claim 2 wherein said key formations are so selected and arranged as to be inter-engageable in only one configuration of said cell module with respect to said housing.

7. The invention according to Claim 2 wherein said housing has a plurality of second key formations each interengeable with the first key formation of any one of a plurality of said cell modules.

8. The invention according to Claim 7 wherein said key formations are so selected and arranged that said cell modules may be held in said housing with said key formations in inter-engagement only at predetermined locations of said housing and wherein any one of said cell modules may be held at any one of the predetermined locations in only one configuration with respect to the housing.

9. The invention according to any one of Claims 4 to 8 wherein a pair of adjacent cell modules are held with a terminal of one adjacent a terminal of opposite polarity of the other when said respective first key formations inter-engaged with said respective second key formations.

10. The invention according to Claim 9 further including rigid means for electrically interconnecting said adjacent terminals of said adjacent cell modules.

11. The invention according to Claim 2 wherein said housing is provided with an openable or removable lid apertured to allowfilling spouts extending upwardly from a cell module to be accessed without need for removal of said lid.

12. The invention according to Claim 2 wherein said housing is provided with a lid wherein at least one terminal of a cell module is adapted for attachment thereto of a terminal post extending through an aperture provided therefore in said lid, whereby said lid is held in place by said terminal post and said terminal may be connected to an external circuit.

13. The invention according to any one of the preceding claims wherein said battery cell module is a wet cell.

14. The invention according to any one of the preceding claims wherein said terminal means comprise at least two terminals projecting from a surface of said cell module.

15. The invention according to Claim 1 wherein said terminal means includes a terminal projecting from a surface of said case and adapted for clamping by fastening means to a terminal of another battery.

16. The invention according to Claim 9 wherein said adjacent terminals are adapted to be held in clamping engagement.

17. A battery cell module substantially as herein described.

18. A battery comprising a plurality of individually replaceable cell modules substantially as herein described.