FIELD OF INVENTION

This invention relates to power packs and in particular to a modular battery system comprising a plurality of interconnectable battery modules.

BACKGROUND OF INVENTION

Electricity prices have been on the increase and will in all likelihood continue to increase going forward. There has also been a significant increase in the demand for electricity and this keeps growing constantly which places a greater load upon the electricity power grid. In many instances, grid power supply has proven to be unreliable and for these reasons alternatives such as renewable sources of energy are becoming more popular. One of the most popular forms of renewable energy is solar energy. There is therefore an ever increasing demand to store energy using fuel cells or battery packs.

Installation of such renewable power supply systems with associated battery packs usually requires the services of a skilled technician with appropriate tools. However, renewable energy sources are popular in remote areas where skilled technicians are scarce. The cost associated with contracting a service provider to complete and maintain a renewable energy installation is a deterrent to its widespread use especially if a technician needs to be contacted each time a battery module needs to be added, replaced or removed from the installation. Furthermore, improper or incorrect installation of a renewable power supply system such as a solar power system, in the absence of a skilled technician, could lead to product or equipment damage and even fire. Multiple vehicle batteries have been used to form battery packs for solar panel power supplies. These batteries are heavy, difficult to handle and do not facilitate simple interconnection between batteries. Accordingly, electrical leads with suitable clamps, or other suitable connection means are required to interconnect the individual batteries with one another. However, these leads are exposed and could lead to a short-circuit and fire when accidentally bridged or incorrectly coupled. Other solar power supply products have complex product specifications which make it difficult for laymen to follow and the quality and/or durability of some products are questionable to say the least.

US 8288035 discloses a modular battery pack comprised of a plurality of modular batteries. Each battery has keyed sidewalls for sliding engagement with adjacent batteries which facilitates connection in series and parallel by using conductive connector bars which attach to exposed terminals or poles on ends of the batteries. A drawback of US 8288035 is that tooling is still required to connect the connector bars. Furthermore, the poles or terminals are exposed which is a safety risk. There is therefore a need for a modular battery system which facilitates simple and safe interconnection of batteries without the use of tools.

It is an object of the invention to provide a battery module and system which overcome or at least alleviate the above drawbacks. SUMMARY OF INVENTION

In accordance with a first aspect of the invention there is provided a battery module which includes:

a conventional chemical cell;

a housing within which the cell is housed;

at least one first electrical connector which is internally electrically connected to the chemical cell for series connection to an adjacent module; at least one second electrical connector which is internally electrically connected to the chemical cell for parallel connection to an adjacent module; and

switching circuitry associated with at least one of the first and/or second electrical connectors, the switching circuitry being configured to prevent incorrect electrical connection of the battery module to an adjacent module by automatically electrically connecting/disconnecting at least part of the connector to/from the chemical cell when the battery module is connected, plug-and-play fashion, to an adjacent module, wherein the battery module is configured for connection in series, in parallel, or in series-parallel combination to one or more adjacent battery modules by way of the first and/or second electrical connectors.

The switching circuitry may include as least one switch which is actuated when two modules are interconnected. The switching circuitry may include switchgear coupled between the cell and the connector, the switchgear being configured to control connection/disconnection of the cell to the connector depending upon a position of the switch. The switchgear may include at least two solid state relays.

The module may include a pair of first complementary electrical connectors, one at either end of the housing and a pair of second complementary electrical connectors. The pair of second connectors may be arranged at opposing top and bottom faces of the housing. The pair of first electrical connectors may be configured for series connection to adjacent modules. The pair of second electrical connectors may be configured for parallel connection to adjoining modules. The switching circuitry may include at least two switches. The switches may be disposed on different faces of the housing.

The housing may have a pair of opposing side panels. The top and bottom of the housing may be non-planar with the top being configured to abut a complemental bottom of a corresponding adjoining module operatively positioned on top of it. The top and bottom of the housing may have complemental arcuate profiles which render multiple modules stackable, one on top of the other. The top and bottom may include corresponding locating formations such that adjoining, vertically stacked modules are configured to mate tongue-in-groove fashion.

Opposing end faces of the housing may be non-planar and complemental which renders a plurality of modules connectable end-to-end as well as top-to- bottom to form an array of modules.

The switching circuitry may include three solid state relays located inside the housing and a pair of push switches. Each switch may be arranged in an end face of the housing and may be connected by way of suitable circuitry to a control terminal of at least one relay.

Each second electrical connector may include a pair of electrical terminals comprising a positive terminal and a negative terminal. Each push switch may be associated with a like terminal of both second electrical connectors.

A front switch may be associated with control of a negative terminal of each of the second electrical connectors and a rear switch may be associated with control of a positive terminal of each of the second electrical connectors. The switching circuitry may be configured to disconnect/connect the second connectors in response to connection/disconnection of the battery module with an adjacent module. The rear switch may be configured to disconnect, by way of the switchgear, the positive terminals of the pair of second connectors upon connection of an adjacent battery module to the rear end of the housing via a first electrical connector. The front switch may be configured to disconnect, by way of the switchgear, the negative terminals of the pair of second connectors upon connection of an adjacent battery module to the front end of the housing via the other first electrical connector. Each push switch may be integrated into a first electrical connector.

One first electrical connector in a pair of first electrical connectors may be one of a male or female type connector, the other being the opposite. One second electrical connector in a pair of second electrical connectors may be one of a male or female type connector, the other being the opposite.

The male type connector may be isolated. The female type connector may be concealed to prevent accidental or unintentional short-circuits.

In accordance with another aspect of the invention, there is provided a modular battery system which includes:

a plurality of battery modules as described above which are interconnected, in plug-and-play fashion, by way of corresponding mating electrical connectors in series, in parallel, or in series-parallel combination.

The battery modules are interconnected in symmetrical fashion without requiring tools to secure the modules together. The modules may form a two- dimensional symmetrical array. A load may be connected to one module of the battery system only, at the same connector, irrespective of the number of modules making up the system.

The system may have one load connection or power take-off point. The system may include an inverter which is connected/connectable to the power take-off point.

The invention extends to a method of creating a modular battery system, the method including:

providing a plurality of battery modules as described above; and electrically interconnecting the battery modules, in plug-and-play fashion, by way of corresponding electrical connectors, in series, in parallel, or in series-parallel combination by stacking the modules on top of one another and/or arranging adjacent modules end-to-end. The method may include interconnecting the battery modules to form an array and applying a load to the system by connecting the load to a power take-off point of the system. A conventional chemical cell may be in the form of a fuel cell or a conventional battery. The module may include a pair of first complementary electrical connectors, one at either end of the housing. The modules may include a pair of second complementary electrical connectors. The second connectors may be arranged at opposing top and bottom faces of the housing. The first electrical connectors may be series connectors. The second electrical connectors may be parallel connectors.

The housing may have a pair of opposing planar side panels. A top and bottom of the housing may be non-planar. Preferably, the top and bottom are curved. The top may be configured to abut a complemental bottom of an adjoining module positioned on top of it. Accordingly, the top may be convexly curved. The opposing bottom of the housing may be concavely curved and configured to receive a complementary shaped top of an adjacent module positioned below it. The top may include mating or locating formations in the form of a pair of tongues disposed toward sides of the top. The bottom may include complementary mating formations in the form of a groove or a pair of grooves configured to receive the tongues. Opposing end faces of the housing may be non-planar and complemental. Accordingly, a first end face may be convexly curved and the opposing second end face may be concavely curved. Accordingly, the shape of the housing may render a plurality of modules vertically stackable, top to bottom and end-to-end to form an array. It is to be appreciated that the modules may also be shaped to have complemental opposing sides. The housing may define a front end and a rear end. The front end may be convexly curved and the rear end may be concavely curved.

The switching circuitry may further include a pair of push-switches. The switches may be normally closed. Accordingly the switches may be push-to- disconnect switches. Each switch may be arranged in an end face of the housing and may be connected by way of suitable circuitry to a relay. The switch may be connected to a control terminal of the relay.

The switching circuitry may be configured to connect/disconnect the parallel connectors in response to connection/disconnection of the battery module with an adjacent module. Accordingly, the rear switch may be configured to disconnect the positive terminals of the pair of parallel connectors upon connection of an adjacent battery module to the rear end of the housing by way of the series connector. Similarly, the front switch may be configured to disconnect the negative terminals of the pair of parallel connectors upon connection of an adjacent battery module to the front end of the housing by way of the opposing series connector.

Each push switch may be integrated or integrally formed with a series connector, i.e. front push switch with front series connector and rear push switch with rear series connector. In an alternative embodiment the push switch may be independent of the series connector.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings.

In the drawings:

Figure 1 shows a front three-dimensional view of a battery module in accordance with a first aspect of the invention;

Figure 2 shows a rear three-dimensional view of the battery module of figure 1 ;

Figure 3A illustrates a partial schematic circuit diagram of load connections of the module of figure 1 ;

Figure 3B illustrates a partial schematic circuit diagram of control connections of the module of figure 1 ;

Figure 4 shows a three-dimensional diagrammatic representation of a modular battery system in accordance with the invention; Figure 5 shows the system of figure 4 schematically;

Figure 6A shows an alternative schematic circuit diagram layout of load connections of a battery module including three solid-state relay components; and

Figure 6B shows an alternative schematic circuit diagram layout of control connections of a battery module including three solid-state relay components.

DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT

The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiments described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not a limitation thereof.

In the figures reference numeral 10 refers generally to a battery module in accordance with a first aspect of the invention. The module 10 includes a conventional chemical cell or fuel cell 12 housed within a housing 14 which comprises a pair of opposing planar side panels 15, a pair of opposing end faces at front 1 1 and rear 13 ends respectively, and a non-planar top 16 and bottom 17. The top 16 is convexly curved and the bottom 17 has a complemental concave curvature which is configured to receive a convexly curved top of an adjacent module thus rendering the modules stackable on top of one another (see figure 4). In order to further enhance the vertical stackability of the modules, the top 16 has a longitudinally extending mating formation in the form of a pair of tongues 18 formed along edges of the side panels 15. The bottom 17 defines a complementary mating formation in the form a groove 19 or a pair of grooves which are shaped to receive the tongues 18. The front end 1 1 of the housing 14 is convexly curved and the opposing rear end 13 is concavely curved, in complemental fashion which renders adjacent modules stackable end-to-end.

The module 10 further includes a pair of complementary first electrical connectors, one at either end of the housing, the first electrical connectors being in the form of series connectors, which implies that they facilitate series connection of the module 10 with an adjacent module. The module 10 also includes a pair of second electrical connectors, one disposed toward the top, and the other disposed toward the bottom, the second electrical connectors being in the form of parallel connectors, which implies that they facilitate parallel connection of the module 10 to an adjacent module. The pair of series connectors accordingly comprises a front series connector 20 provided in the front end 1 1 of the housing 14 and a rear series connector 21 provided in the rear end 13 of the housing. The connectors may be in the form of conventional twin terminal electrical connectors, also known as Anderson connectors. One of the series connectors is a male type connector, the other being a female type connector. In this embodiment, the front series connector 20 is a male type connector and the rear series connector 21 is a complementary female type. Similarly, a top parallel connector 22 is provided in the top 16 of the housing and a bottom parallel connector 23 is provided in the bottom 17 of the housing, the two connectors making up the pair of parallel connectors. One of the parallel connectors is a male type connector, the other being a female type connector. Again, the top parallel connector 22 is a male type connector and the bottom parallel connector 23 is a complemental female type connector. Each connector has two electrical terminals which are internally, directly or indirectly electrically connected to the chemical cell 12. The series connectors 20, 21 are configured for series connection of the module 10 with an adjacent module and the parallel connectors 22, 23 are configured for parallel connection of the module 10 with an adjacent module. With reference to figure 3A, the terminals of each parallel electrical connector 22, 23 include a positive terminal 22.1 , 23.1 and a negative terminal 22.2, 23.2. The module 10 further includes switching circuitry 27 which includes at least two solid-state relays which are housed inside the housing 14. The pair of relays comprises a positive relay 24 and a negative relay 25 which are electrically connected to the cell 12. As is conventional, each relay has a pair of control terminals 24.1 , 25.1 at one end and a pair of load terminals at the other end 24.2, 25.2. The switching circuitry 27 further includes a pair of push- switches 26, 28 which are normally closed. Preferably the switches 26, 28 are in the form of push-to-disconnect switches, each being arranged in an end face of the housing 14. Although this has not been illustrated, the respective push switches 26, 28 may be integrated or integrally formed with one of the series electrical connectors 20, 21 . The switching circuitry 27, i.e. the push switches 26, 28 and relays 24, 25 are configured to prevent incorrect electrical connection of the battery module 10 to an adjacent module by electrically connecting/disconnecting individual terminals of the respective parallel connectors 22, 23 from the chemical cell 12 depending on the position of the push switches 26, 28. The relays 24, 25 serve to isolate the switches 26, 28 from high current connection/disconnection which could damage the switches 26, 28. Accordingly, the battery module 10 is configured for connection in series with one or more adjacent identical battery modules 10 via interengagement of the series connectors 20, 21 of adjacent modules 10. The battery module 10 is also configured for connection in parallel with one or more adjacent identical battery modules 10 via interengagement of the parallel connectors 22, 23. Furthermore, the battery module 10 is configured for connection in series- parallel combination with one or more adjacent identical battery modules 10 by way interengagement of the series and parallel connectors 20, 21 , 22, 23, provided the combination forms a matrix of modules 10.

Each push switch is connected to a control terminal 24.1 , 25.1 of one relay by way of suitable internal wiring. Referring now specifically to figure 3B, a rear push switch 26, which is mounted to the rear end 13 of the housing 14 is associated with the positive relay 24 and is connected in series between a negative terminal of the cell 12 and one control terminal of the relay 24. The other control terminal is connected to the positive terminal of the cell 12. Now referring back to figure 3A, the positive terminal 22.1 , 23.1 of each parallel connector 22, 23 is connected to one load terminal of the positive relay 24. The other load terminal is connected to the positive terminal of the battery or cell 12. The load terminals 24.2 of the relays 24, 25 are normally open, i.e. if power is not supplied to the control terminals 24.1 , 25.1 , the load terminals 24.2, 25.2 are open. Hence, when the rear push switch 26 is pushed in, i.e. when adjacent modules are connected to one another in series, the rear push switch 26 is depressed and opened and power to the control terminals 24.1 of the relay 24 is interrupted and hence the load terminal 24.2 of the relay 24 is opened and power to the positive terminal 22.1 , 23.1 of each parallel connector is disconnected.

The same holds true for the negative relay 25. Turning again to figure 3B, in this instance a front push switch 28, which is mounted to the front end 1 1 of the housing 14 is connected by suitable internal wiring, in series between a negative terminal of the cell 12 and one control terminal of the negative relay 25. The other control terminal is connected to the positive terminal of the cell 12. Referring back to figure 3A, a first load terminal of the negative relay 25 is connected to the negative terminal of the cell 12. The other load terminal is connected to the negative terminal 22.2, 23.2 of each of the parallel connectors 22, 23. Therefore, when the front series connector 20 of the module 10 mates with an adjacent module, the front push switch 28 is depressed. This breaks contact and hence interrupts power to the control terminal 25.1 of the negative relay 25 and, accordingly, breaks the connection of the negative terminal 22.2, 23.2 of the respective parallel connectors 22, 23 with the negative terminal of the cell 12.

Accordingly, each push switch 26, 28 is associated with a like terminal of both parallel electrical connectors 22, 23. The front switch 28 is associated with and controls electrical connection to the negative terminal 22.2, 23.2 of each of the parallel electrical connectors. The rear switch 26 is associated with and controls electrical connection to the positive terminal 22.1 , 23.1 of each of the parallel electrical connectors. As a result, the switching circuitry 27 is configured to disconnect terminals of the parallel connectors 22, 23 from the cell 12 in response to series connection of the battery module 10 with an adjacent module. Accordingly, the rear switch 26 is configured to disconnect the positive terminals 22.1 , 23.1 of the pair of parallel connectors upon connection of an adjacent battery module to the rear end 13 of the housing by way of the series connector 21 . Similarly, the front switch 28 is configured to disconnect the negative terminals 22.2, 23.2 of the pair of parallel connectors upon connection of an adjacent battery module to the front end 1 1 of the housing 14 by way of the opposing series connector 20.

The rear series connector 21 comprises a pair of positive terminals 21 .1 , 21 .2 which are electrically connected or bridged when the rear push switch 26 is not depressed. One positive terminal 21 .1 is connected to the positive terminal of the cell 12. The other positive terminal 21 .2 is connected to a positive terminal 20.1 of the front series connector 20. Depression of the rear push switch 26 serves to break contact between the positive terminals 21 .1 , 21 .2 of the rear series connector 21 . This will be elaborated on below with reference to figures 6 and 7. The front series connector 20 comprises positive 20.1 and negative 20.2 terminals. The negative terminal 20.2 is connected to the negative terminal of the cell 12 and the positive terminal 20.1 is connected to the positive terminal 21 .2 of the rear series connector 21 , as mentioned above.

In figures 6A and 6B, numeral 100 refers to a battery module in accordance with the invention which includes an alternative, preferred, internal circuit arrangement when compared to that of figures 3A and 3B. Figure 6A illustrates relay load circuit connections and figure 6B illustrates relay control connections. The same reference numerals used above have again been used in figures 6A and 6B to refer to like parts. The battery module 100 includes a positive solid state relay 24 and a negative solid state relay 25, similar to the module 10 illustrated in figures 3A and 3B but includes an additional third solid state relay 29 and a number of connector blocks 30. Wires, leads or tracks, in the case of a printed circuit board (PCB), interconnect the relays 24, 25, 29, switches 26, 28 and connector terminals 20, 21 , 22, 23 via the blocks 30. The functioning of the positive and negative relays 24, 25 remain essentially the same as described with reference to figures 3A and 3B and, accordingly, will not be repeated here. However, the purpose of the third solid state relay 29 is to disconnect the one positive terminal 21 .2 from its neighbouring positive terminal 21 .1 as well as from the positive terminals 22.1 , 23.1 of the respective parallel connectors 22, 23 when the push switch 26 is depressed. Therefore, as explained above, when the push switch 26 is not depressed, the terminals 21.1 , 21.2 are essentially bridged. But when the push switch 26 is depressed as a result of engagement of an adjacent module, the relay 29 serves to break the connection between the terminals 21 .1 , 21 .2 and between the terminal 21 .2 and the positive terminals 22.1 , 23.1 of the respective parallel connectors 22,

23. Accordingly, referring now made to figure 6B, the push switch 26 is in series connection between the control terminals 24.1 and 29.1 of the relays

24, 29 and the cell 12 such that when the switch 26 is opened (depressed), power to the control terminals 24.1 , 29.1 of both of the relays 24, 29 is interrupted and, accordingly, the terminals connected to opposite ends of load terminals 24.2, 29.2 are disconnected from one another. The same applies to relay 25 when push switch 28 is depressed.

In figures 4 and 5, reference numeral 50 indicates a modular battery system in accordance with the invention which comprises a 2x2 array or matrix of four battery modules 10.1 , 10.2, 10.3, 10.4 as described above stacked and connected one to the other. If each module 10 is a 12V battery capable of 100Ah, the system 50 is a 24V system capable of 200Ah current supply. Naturally larger or smaller systems are also conceivable based upon the same principles described herein. The battery system is modular and any linear or rectangular array of modules 10 can be constructed. Modules 10.1 and 10.2 are in series connection by way of engagement of series connectors 20, 21 which results in front push switch 28.1 of 10.1 and rear push switch 26.2 of 10.2 being depressed which in turn breaks the connection between the cell 12 and terminals 22.2.1 and 23.2.1 of 10.1 and 22.1 .2 and 23.1 .2 of 10.2 as well as the bridge connection between terminals 21 .1 .2 and 21 .2.2 of 10.2. Rear push switch 26.1 of 10.1 is not depressed nor is front push switch 28.2 of 10.2 and accordingly the connection between terminals 22.1 .1 and 23.1 .1 of 10.1 remains as well as the connection between 22.2.2 and 23.2.2 for 10.2. The same applies to modules 10.3 and 10.4 which are connected in parallel to 10.1 and 10.2 by way of the corresponding mating parallel connectors 22, 23. A load 40 is applied to front series connector 20 of module 10.4.

The invention presents an improvement over the prior art because the system 50 permits plug-and-play functionally of modules 10 without needing tools to connect the respective modules 10 together. The complemental concave/convex shape of the front 1 1 and rear 13 ends of the housing 14 as well as the tongue 18 and groove 19 formed in the top 16 and bottom 17, respectively, prevents incorrect connections from being formed between adjacent modules and therefore obviates the need of a technician to construct the battery system. It may also not be necessary to disconnect the load 40 when joining modules together. In other words, modules 10 can be easily added to or removed from the system 50 by hand without the need for skilled personnel or tools such as spanners, sockets or wrenches. Furthermore, the switching circuitry 27 and concealed female connectors 21 , 23 and isolated male connectors 20, 22 provide for electrically safe connection and disconnection and eliminates the possibility of incorrect electrical connections being established between adjacent modules 10 thereby preventing damage to equipment as well as preventing accidental electrical shorts which could lead to fire. As mentioned, the female electrical connectors 21 , 23 are not exposed which is an added benefit from a safety point of view. The male type connectors 22, 20 are insulated to prevent undesirable short circuits or electrical shock.