GB2545567A

GB2545567A - Battery pack assembly

Info

Publication number: GB2545567A
Application number: GB1620810.0A
Authority: GB
Inventors: Cummins Carlton
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-12-11
Filing date: 2016-12-07
Publication date: 2017-06-21
Anticipated expiration: 2036-12-07
Also published as: GB201521887D0; GB2545567B; GB2545267A; GB201620810D0

Abstract

A battery pack assembly (1, figure 1) comprises two holding frames (3) holding a plurality of cells (2) longitudinally therebetween, wherein two or more of the plurality of cells are connected by a conductive means 7 and the holding frames are reversibly held together by a fastening means (10) causing terminals of the cells to be urged against the conductive means, a base of at least one holding frame comprises one or more elastomeric protrusions (6, figure 3) on a surface facing the opposing frame, wherein parts of the conductive means lie between one or more of the elastomeric protrusions and one or more cell terminals such that urging of the frames together by the fastening means causes the conductive means to be urged into contact by the elastomeric protrusions with said one or more terminals. The holding frame may comprise base protrusions (8, figure 2) and side walls (5) comprising a plurality of concave arcuate sections. The fastening means are preferably screws and the conductive means may comprise one or more conductive plates. The assembly may comprise cylindrical lithium-ion batteries and may be for use with an electric bicycle.

Description

Battery Pack Assembly

The present invention relates to a battery pack assembly. Particularly, but not exclusively, the present invention relates to a large format lithium-ion battery pack assembly, for use with an electric vehicle such as an electric bike, and which is easier to disassemble than assemblies currently used in industry.

Large format battery packs using cylindrical cells often have a plurality of cells, typically 15 or more cells, electrically connected and presented as a single unit called a battery module. In industry, these modules are typically assembled using permanent assembly techniques (structural adhesives, soldering etc.). These permanent assembly techniques present challenges for repairing or reusing the modules, as the individual components of the assembly cannot easily be accessed or removed. This also makes it difficult to recycle the modules, as the various materials cannot be easily separated.

This can lead to energy storage products which are not aligned with EU waste management legislations and prohibits greater revenue opportunities in the repair and repurposing of batteries and battery modules.

The present invention arose in an attempt to provide a more readily recyclable battery pack assembly.

According to the present invention there is provided a battery pack assembly comprising two holding frames, wherein the two holding frames hold a plurality of cells between them, each cell being held longitudinally between the two holding frames, wherein two or more of the plurality of cells are connected by a conductive means, and wherein the two holding frames are reversibly held together by a fastening means, wherein the fastening means cause terminals of the cells to be urged against the conductive means and removal or loosening of the fastening means enables the cells to be freed from the assembly, at least one holding frame comprising one or more elastomeric protrusions on a surface facing the opposing frames and wherein the conductive means are positioned such that parts of them lie between one or more elastomeric protrusions and one or more cell terminals, such that the urging of the frames together by the fastening means causes the conductive means to be urged into contact by the elastomeric protrusions with said one or more terminals.

The present invention allows for the complete disassembly of a large format battery pack assembly into its individual components. The ability to completely disassemble the assembly permits the module to be repaired via the replacement of individual cells or other components, allows individual components of the module to be reused for further applications at the end of the useful life of the complete assembly, and allows for improved recycling as each of the individual components of the module can be separated and sorted for recycling accordingly.

As well as assisting manufacturers to meet EU waste management legislation, the ability to reuse, repair and recycle individual components of battery modules would also save money and resources for the manufacturers. Individual or multiple cells may be replaced with ease, meaning the assemblies could be repeatedly rebuilt at end of life instead of being disposed. It also presents the opportunity for the reuse of cells from a module in other energy storage applications when they no longer perform in the original module application or when the module is no longer required.

In one embodiment of the present invention, the assembly consists of a set of cells positioned between two parallel holding frames, each cell being held longitudinally between the two holding frames by virtue of the fastening means being 'tightened' to clamp the cells longitudinally between the holding frames.

One of the frames may be an access lid, which can be opened or removed to gain access to the cells.

Each holding frame may comprise a generally flat base and side walls, wherein each side wall may further comprise a plurality of concave arcuate sections complementary to the side wall of the cells to be inserted into the assembly. The holding frames may further comprise a plurality of protrusions extending perpendicularly from the base, wherein the walls of the base protrusions may comprise a plurality of concave arcuate sections complementary to the side wall of the cells to be inserted into the assembly.

The holding frame and/or access lid may be shaped to accommodate cells of different shapes than cylindrical ones, eg rectangular or other shapes. It may have differently shaped protrusions or other features of its surface (eg inner surface) which are shaped to receive cells.

Each holding frame may therefore define a plurality of whole or part generally cylindrical regions, each defined by a concave arcuate side wall section and at least one concave arcuate base protrusion wall section, wherein each generally cylindrical region may seat a cylindrical cell.

The conductive means (e.g. one or more conductive plates) may be positioned laterally across the base of each holding frame and may lie across the multiple whole or part generally cylindrical regions (i.e. to bridge them) so as to electrically connect multiple seated cells. The conductive plates may be any shape which would cover more than one generally cylindrical region, such as linear, U-shaped, S-shaped, L-shaped, T-shaped, H-shaped, etc. The gaps in the walls of the generally cylindrical regions allow for the insertion of conductive plates in various arrangements; changing the arrangement of the conductive plates adapts the battery module for various applications using the same holding frame. Conductive plates may be provided on both holding frames, the arrangement of the conductive plates in each of the two holding frames preferably being complementary, such that they form a complete circuit when the plurality of cells are held within the two holding frames, electrically connecting all of the cells in the assembly in series. For example the cells may be arranged with neighbouring cells alternatively positioned with the positive terminal upwards and the positive terminal downwards respectively, and the positive and negative terminals on each side being connected together, so that a complete circuit is formed. Means are provided to connect the appropriate conductive plates to external means for driving a vehicle or other equipment, control/processing means and so on. There may be electrical terminals connected to some of the conductive plates.

The two holding frames are held together by a fastening means, which may consist of a plurality of fastening screws. Each fastening screw may each thread through a hole in each of the two holding plates and act to compress the assembly, encouraging contact between the cells and the conductive means. The threaded holes in each of the holding frames may be positioned in the holding frame base protrusions.

The elastomeric protrusions are preferably positioned generally where the terminals of one or more cells lie when the cells are seated within the holding frames. The conductive means may be positioned such that parts of them lie between the elastomeric protrusions and one or more cell terminals, such that the elastomeric protrusions act to further encourage contact between the one or more cell terminals and the conductive means when the assembly is under compression from the 'tightening' of the fastening means. This ensures quality electrical contacts are maintained even when the assembly undergoes vibration.

The design of the assembly also allows for the integration of liquid cooling for high power applications.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which:

Figure 1 shows a battery pack assembly;

Figure 2 shows a holding frame;

Figure 3 shows the holding frame with the elastomeric members inserted;

Figure 4 shows an arrangement of conductive plates;

Figure 5 shows the conductive plates of Figure 4 inserted into the holding frame of Figure 2 or 3;

Figure 6 shows two holding frames, each with conductive plates inserted, to form a complete circuit once the plurality of cells are inserted.

Referring to Figure 1, one embodiment of a battery pack assembly 1 is shown. The battery pack assembly 1 comprises a plurality of lithium-ion cells 2, each cell being held longitudinally between two holding frames 3. The generally rectangular holding frames 3 (which may be made of a plastic material for example) each comprise a generally flat base 4, side walls 5 extending generally perpendicularly from the base 4, elastomeric members 6, conductive plates 7, screw slots 8 and battery terminals 9. The holding frames 3 are reversibly held together by fastening screws 10, with the plurality of cells 2 held in place between the holding frames 3 by the compressive force of the fastening screws 10, which each thread through a screw slot 8 in each of the two holding frames 3.

The fastening screws (or other fasteners) may be fastened to a specific tension. This can be achieved by lock nuts or otherwise.

Referring to Figure 2, one embodiment of a holding frame 3 is shown. The side walls 5 of the holding frame 3 each comprise a plurality of concave arcuate side wall sections 11. A plurality of base protrusions 12 also extend perpendicularly from the base 4. The side walls of the base protrusions 12 may comprise a plurality of concave arcuate protrusion wall sections 13. Each concave arcuate side wall section 11 in combination with at least one concave arcuate protrusion wall section 13 thereby defines part of a generally cylindrical region 14 to seat a cylindrical cell 2. The screw slots 8 for the receiving of the fastening screws 10 are positioned in some of the base protrusions 12. The base 4 further comprises a plurality of recesses 15, in each of which may sit an elastomeric member 6 forming an elastomeric protrusion. This may be of rubber, a rubber compound, a plastics material and so on.

Instead of actuate sections, for accommodating generally cylindrical cells, the protrusions may be otherwise shaped to accommodate other cell shapes, eg generally planar intersections or square to accommodate rectangular or square cells. Thus, the battery cells may be of any desired shape.

Figure 3 shows the holding frame of Figure 3, wherein each of the recesses 15 is fitted with an elastomeric member 6. These members are therefore provided on a surface of the holding frame which opposes the opposite frame, ie on the base of the frame.

Figure 4 shows one possible arrangement of the conductive plates 7 to be inserted into a holding frame 3a. In this example, three cells would be electrically connected by each of the two linear conductive plates 7a, and six cells would be electrically connected by each of the four U-shaped conductive plates 7b. An opposing holding frame 3b (not shown) will be associated with an arrangement of conductive plates 7 complementary to the arrangement of conductive plates 7 inserted into the holding frame 3a, such that all of the plurality of cells 2 are electrically connected in a desired arrangement, for example in series, in parallel, or in series-parallel (i.e. wherein one set of cells in parallel are connected in series with one or more further sets of cells also in parallel). The end plates 7a each have projections 16 which connect with the battery terminals 9 on one of the holding frames 3, to enable the plurality of cells 2 to be connected to an external circuit.

Figure 5 shows the holding frame 3a in combination with conductive plates 7 of Figure 4. The conductive plates 7 are positioned across the base 4 of the holding frame 3a and are positioned to extend across a plurality of generally cylindrical regions 14, so as to electrically connect a plurality of cells 2 when the plurality of cells 2 are each positioned within a respective generally cylindrical region 14 and held between the holding frames 3. The compression caused by the tightening of the fastening screws 10 encourages contact between the plurality of cells 2 and the conductive plates 7, wherein the conductive plates 7 are further urged towards the plurality of cells 2 by the elastomeric members 6 urging the conductive plates 7 upwardly, ensuring robust electrical contacts.

Figure 6 shows one example of how the conductive plates 7 may be positioned across the bases 4 of each of the two holding frames 3a and 3b to form a complete circuit (once the plurality of cells 2 are inserted and compressed by the fastening means). Each of the plurality of cells 2 must be orientated such that the polarity of each cell 2 opposes the polarity of the adjacent cell in the series (for example, the first cell in the series is positioned with the positive terminal positioned towards holding frame 3a, the second cell in the series is positioned with the positive terminal positioned towards holding frame 3b, and so on).

Instead of screws (and threaded holes into which the screws are located), other fastening means which can be tightened to clamp or urge the plates towards each other may be provided.

Instead of terminals 9 on the holding frame 3 connecting to tabs 16 of the conductive plates 7, other connecting means may be provided to connect the arrangement of batteries to an external circuit. This includes, but is not limited to, an arrangement wherein the external circuit connects directly to the conductive means, an arrangement wherein the two terminals 9 are not positioned on the same holding frame 3, or an arrangement wherein there are more than two terminals 9 to allow more than one circuit to be independently connected to the module, wherein the conductive means arrangement can be varied to select how many cells 2 are connected to each of the connected circuits respectively.

Conductive means and/or elastomeric protrusions may be necessary just on one side of a cell array in some embodiments.

In embodiments one of the holding frames (generally an upper most one) may be an access lid. This can be removed or perhaps opened to enable access to cells within, for replacement or maintenance of the cells. The access lid may have conductive means and perhaps also elastomeric portions or may in other embodiments not be provided with these, in which case the electrical connections are all made at the side of the cells distal from the access lid.

The lid may be fastened to the assembly in the same way, via reversible fasteners such as machine screws or bolts. These are inserted via holes in the lid and align with holes (eg same size holes) in the holding frame. The cells, compression nodes, and conductive plates are sandwiched in between.

The above embodiments of the present invention have been described byway of example only and it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the appended claims.

The drawings thus show, in a broad aspect, a battery back assembly comprising two holding frames, wherein the two holding frames hold a plurality of cells between them, each cell being held longitudinally between the two holding frames, wherein two or more of the plurality of cells are connected by a conductive means, and wherein the two holding frames are reversibly held together by a fastening means, wherein the fastening means cause terminals of the cells to be urged against the conductive means and removal or loosening of the fastening means enables the cells to be freed from the assembly.

Claims

1. A battery pack assembly comprising two holding frames, wherein the two holding frames hold a plurality of cells between them, each cell being held longitudinally between the two holding frames, wherein two or more of the plurality of cells are connected by a conductive means, and wherein the two holding frames are reversibly held together by a fastening means, wherein the fastening means cause terminals of the cells to be urged against the conductive means and removal or loosening of the fastening means enables the cells to be freed from the assembly, at least one holding frame provided with one or more elastomeric protrusions on a surface facing the opposing frame and wherein the conductive means are positioned such that parts of them lie between one or more elastomeric protrusions and one or more cell terminals, such that the urging of the frames together by the fastening means causes the conductive means to be urged into contact by the elastomeric protrusions with said one or more terminals.

2. A battery pack as claimed in claim 1 where one of the holding frames is an access lid.

3. A battery pack assembly as claimed in any preceding claim, wherein at least one holding frame comprises one or more terminals for connection to an external electrical circuit.

4. A battery pack assembly as claimed in any preceding claim, wherein the conductive means comprises one or more conductive plates.

5. A battery pack assembly as claimed in Claim 5, wherein one or more of the conductive plates comprise means to provide a means for connecting the conductive plates to an external circuit.

6. A battery pack assembly as claimed in Claim 5, the means for connecting the conductive plates to an external circuit comprises at least one conductive plate projection.

7. A battery pack assembly as claimed in any preceding claim, wherein at least one holding frame comprises base protrusions extending perpendicularly from the base.

8. A battery pack assembly as claimed in Claim 7, wherein the walls of the one or more base protrusions comprise a plurality of concave arcuate sections.

9. A battery pack assembly as claimed in Claim 8, wherein each concave arcuate protrusion wall section has a radius of curvature generally equal to the radius of one of the plurality of cells, so that a cell is at least partially received by the concave arcuate section.

10. A battery pack assembly as claimed in any preceding claim, wherein at least one holding frame comprises a base and side walls.

11. A battery pack assembly as claimed in Claim 10 wherein at least one of the holding frame side walls each comprise a plurality of concave arcuate sections.

12. A battery pack assembly as claimed in Claim 11, wherein the cells are generally cylindrical, and the plurality of concave arcuate sections each have a radius of curvature substantially equal to the radius of one of the plurality of cells, so that a cell is at least partially received by the concave arcuate section.

13. A battery pack assembly as claimed in Claim 12 when dependant on Claim 9, wherein the one or more base protrusions are positioned such that the concave arcuate side wall sections and the concave arcuate protrusion wall sections define at least part of a plurality of generally cylindrical regions to each seat a cylindrical cell.

14. A battery pack assembly as claimed in Claim 13, when dependent upon Claim 2 or any Claim dependant thereon, wherein each elastomeric protrusion is positioned centrally in a generally cylindrical region.

15. A battery pack assembly as claimed in any preceding claim, wherein the fastening means comprises a plurality of fastening screws.

16. A battery pack assembly as claimed in Claim 15, wherein each holding frame comprises a plurality of threaded holes through which each fastening screw may be threaded.

17. A battery pack assembly as claimed in Claim 16, when dependant on Claim 5 or any Claim dependant thereon, wherein each threaded hole is positioned in a base protrusion.