GB2588391A

GB2588391A - A battery pack and method for removing at least one cell from a battery pack

Info

Publication number: GB2588391A
Application number: GB1915146.3A
Authority: GB
Inventors: Flannery Barry
Original assignee: Xerotech Ltd
Current assignee: Xerotech Ltd
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2021-04-28
Also published as: GB201915146D0

Abstract

A method for removing at least one cell 2 from a battery pack 1 comprising at least two cells that are arranged parallel to each other and are parallel to a given direction is disclosed. The space between and/or around the cells comprises at least a polymeric-based filler compound 6, the method being characterised in that a mechanical pushing force is applied and/or transmitted to at least one cell. The mechanical pushing force is directed along the given direction and is configured to separate/eject the cell from the remaining part of the battery pack. A machine for carrying out the method is also disclosed. Preferably, the machine 10 comprises a robotic arm or gantry 12 carrying one or more pusher rods 11 that may be activated simultaneously or sequentially.

Description

A BATTERY PACK AND A METHOD FOR REMOVING AT LEAST ONE CELL

FROM A BATTERY PACK

The present invention relates to non-destructive recovery of cells from a battery pack for the purpose of recycling the cells.

Batteries, in particular lithium-ion batteries, are becoming increasingly widespread in many fields such as industry and transportation as powertrains become gradually more electrified. Furthermore, in the automotive space in particular, a major shift is currently underway to battery-powered electric vehicles. It is anticipated that by the mid-2020s there will be millions of fully electric vehicles in operation and by 2025 it is expected that many early generation electric vehicles will reach their end of life. Therefore, the recycling of lithium-ion battery packs is a significant area of research today as it will present a major environmental challenge in the future. Automakers intend to repurpose end of life vehicle battery packs for new, so-called "second life" applications like energy storage. A battery pack is defined as being at its end-of-life when its capacity is reduced to 70-80% of its original capacity. Such batteries are still useful in other markets outside of transportation although ultimately even repurposed packs will reach their end of life and need to be recycled.

The recycling and material recovery of lithium-ion cells from battery packs is a rapidly growing area but a significant challenge is the large variation in battery pack designs and manufacturing processes. High variability across incoming feedstock significantly increases costs and reduces efficiency. At present recycling of such battery packs is generally only commercially viable at large scales. In this context there is the need for a versatile method of recovering cells from battery packs in near pristine condition and free of contaminants, thus facilitating high volume recycling of cells with larger batch runs and avoiding multiple bespoke processes for specific battery modules.

The presence of certain materials such as silicone-based materials or adhesives in electrical hardware such as battery packs can significantly complicate, or even prevent, the commercial viability of recycling such hardware. Adhesives and silicone compounds have poor recycling characteristics and are generally subject to heat energy recovery (burning).

While these materials can be removed via chemical dissolution, such processes are costly and require hazardous chemicals which can be environmentally damaging. Furthermore, the chemicals used in such processes may negatively interact with the other components of the hardware and may impede later recycling efforts. Against this backdrop, there is a need for a method of recycling electrical hardware, such as battery packs employing silicone-based materials or adhesives, which is not environmentally damaging.

It is an object of the present invention to prevent or mitigate the above-mentioned problems by providing a battery pack wherein its cells can be easily detached and/or separated, preferably at the end of their useful life in order to be recovered and recycled.

Another object of the invention is to provide a battery pack that is significantly improved in terms of protection against thermal propagation within the same battery pack.

Another object of the invention is to provide a battery pack that is significantly improved in terms of vibration resistance and impact protection.

Another object of the invention is to provide a battery pack wherein the cells can be separated/removed in near pristine condition and free of contaminants.

Another object of the invention is to provide a battery pack that can be easily recycled at low-cost.

Another object of the invention is to provide a battery pack that can be recycled without the use of chemical dissolution, thus avoiding a significant environmental impact. Another object of the invention is to provide a method that enables the removal of one or more cells from a battery pack.

Another object of the invention is to provide a machine that enables the removal of one or more cells from a battery pack.

Another object of the invention is to provide a method and a machine that are sufficiently versatile to remove cell(s) from a variety of battery packs.

Another object of the invention is to provide a method and machine that are easily and quickly adjustable according to the features, types and size of a specific battery pack.

Another object of the invention is to provide a method and machine that enable an accurate and clean removal of one or more cells from a battery pack.

Another object of the invention is to provide a machine that enables the removal of a plurality of cells at the same time.

Another object of the invention is to provide a machine that enables the removal of a specific single cell within a battery pack comprising a plurality of said cells.

According to a first aspect of the invention there is provided a battery pack comprising at least two cells that are arranged parallel to each other and wherein the space between and/or around the cells comprises a polymeric-based filler compound. Advantageously, the battery pack comprises a plurality of cells that are arranged in an array pattern.

Preferably, the plurality of cells are reciprocally spaced and the space between said cells is completely filled with a polymeric-based filler compound.

Preferably, said polymeric-based filler compound is a potting compound.

Preferably, said polymeric-based filler compound acts as a filler of the space between said cells.

Preferably, said polymeric-based filler compound acts as a connector for joining each cell with one or more adjacent cell(s).

Preferably, said polymeric-based filler compound is a solid or gelatinous compound.

Preferably, said polymeric-based filler compound comprises a thermo-setting plastic.

Ideally, said polymeric-based filler compound comprises a polymeric foam. Preferably, said polymeric-based filler compound is foam rubber. Preferably, said polymeric-based filler compound is polyurethane foam.

Optionally, said polymeric-based filler compound comprises silicone.

Preferably, said polymeric-based filler compound comprises a compound for resistance to shock and vibration.

Optionally, said polymeric-based filler compound comprises a silicone rubber gel. Optionally, said polymeric-based filler compound comprises an epoxy resin.

Advantageously, said battery pack does not comprise traditional adhesive or glue, such as methyl methacrylate adhesive (MMA) or other UV curing adhesives, for bonding the cells to the housing and/or closure of said battery pack.

Ideally, the space between the cells is entirely filled with a polymeric-based compound, thus providing additional mechanical rigidity to the resulting assembly.

Preferably, the cells are completely encapsulated in said polymeric-based filler compound.

Preferably, said cells are all of the same type. Preferably, said cells have all the same shape. Preferably, said cells have all the same dimensions.

Preferably, said cells are lithium-ion cells.

Preferably, the cells have a cylindrical or parallelepipedic shape.

Preferably, the cells are of the type having two opposite bases that are substantially parallel with each other and are separated by a sidewall.

Preferably, said bases have the same shape and area.

Preferably, the cells are of the type having a longitudinal extension with two opposite bases that are parallel with each other and that are perpendicular to said longitudinal extension, said bases being separated by a side wall developing along said longitudinal extension. Preferably, said longitudinal extension is greater than the dimensions of the cross-section of said cell.

Preferably, each cell comprises a positive electrode at one of said bases and a negative electrode at the other base. Preferably, said sidewall of the cell is made of metal and also forms part of the negative electrode.

Preferably, said polymeric-based filler compound is arranged only in correspondence and between said sidewalls of the cells. Preferably, said polymeric-based filler compound does not adhere at all to the bases of the cells.

Preferably, said battery pack comprises a substantially rigid assembly with a matrix of cells wherein the space between and/or around said cells is filled with said polymeric-based filler compound.

Ideally, in said assembly the cells are aligned along at least one direction.

Preferably, in said assembly the cells are aligned along two directions that are reciprocally orthogonal.

Preferably, the cells are provided with means for preventing direct adhesion of the polymeric-based filler compound to the external surface of the cells.

Preferably, said means for preventing direct adhesion of the polymeric-based filler compound comprise a sheathing means configured for removably covering, at least in part, the external surface of each cell.

Preferably, said sheathing means is configured for removably covering, at least partially, one or both the bases of each cell in correspondence with the edge of said base or bases.

Ideally, said sheathing means is configured for removably covering only the sidewall of each cell, without overlapping the any other surface of the corresponding cell.

Preferably, said sheathing means comprises a sleeve covering at least the sidewall of each cell.

Preferably, said sheathing means is made of polymeric material.

Ideally, said sheathing means consists of a thin external polymer sleeve to prevent direct adhesion of the polymeric-based filler compound to the external surface of the metal side wall of each cell.

Advantageously, said sheathing means is provided for the electrical insulation and short circuit protection between the two bases of each cell, preferably between positive and negative battery electrodes.

Preferably, the sheathing means acts both to prevent direct adhesion of the polymeric-based filler compound to the metal side wall of each cell and to electrically insulate the cell, providing short circuit protection between the positive and negative battery electrodes.

Preferably, said battery pack comprises means for maintaining the cell spacing and pattern.

Preferably, said means for maintaining the cell spacing and pattern comprises at least one plate or clamshell configured for maintaining the cell spacing and pattern. Ideally the battery pack comprises a lower clamshell and an upper clamshell.

Preferably, the battery pack comprises an upper/first plate or clamshell in correspondence of the upper/first base of the cells.

Preferably, the battery pack comprises a lower/second plate or clamshell in correspondence of the lower/second base of the cells.

Preferably, the or each clamshell comprises a plurality of recesses, there being one recess for each cell of the battery pack.

Optionally each recess acts to receive and/or retain a base of a corresponding cell. Preferably, each recess is configured, in terms of size and shape, to accommodate at least a part of the sidewall of a cell.

Preferably, said means for maintaining the cell spacing and pattern comprises a frame for retaining said cells.

Preferably the frame is a box-shaped frame.

Preferably the frame comprises the polymeric-based filler compound.

Preferably, said polymeric-based filler compound substantially fills at least a portion of the space between and around said cells within said frame.

Ideally, said polymeric-based filler compound substantially fills at least a portion of the space between and around said cells within said frame.

Preferably, said means for maintaining the cell spacing comprises an inflatable thermal management system. Ideally the thermal management system is configured so that the force of the expanded duct acts along a direction angled, preferably perpendicular, with respect to the longitudinal axis of each cell, thus maintaining the position and rigidity of the cells assembly. Ideally the force which causes the duct to expand is pneumatic, hydrodynamic or hydrostatic.

Preferably, said battery pack is configured to aid the mechanical ejection of each cell from the assembly of the battery pack.

According to a second aspect of the invention there is provided a reinforcement means adapted to aid in the removal of one or more cells from a battery pack, the reinforcement means comprising: a body adapted to apply a force to a polymeric-based filler compound surrounding a cell; and at least one passage adapted to allow a cell to pass therethrough. Advantageously, the reinforcement means is adapted to aid in the clean removal of cells from a battery pack Ideally the reinforcing means comprises a plurality of passages.

Preferably the or each passage comprises an aperture in the body of the reinforcement means.

Preferably, the or each passage is sized such that there is sufficient clearance for the cell to be ejected and prevent snagging.

Preferably, the or each aperture has a shape corresponding to the base of the corresponding cell Ideally, the diameter of the or each aperture is slightly larger than the diameter of the base or cross-section of a cell.

Preferably, the reinforcing means is configured to mechanically support an assembly comprising an array or matrix of cells with the polymeric-based filler compound in the space between said cells, and to prevent shearing during cell ejection from said assembly.

Preferably the reinforcing means is adapted to concentrate a longitudinal force applied to a cell on the interface between the external surface of the cell and a sheathing means and/or polymeric-based filler compound surrounding said cell. Advantageously, concentration of the force in this way causes a cell and the surrounding sheathing means and/or polymeric-based filler compound to be decoupled and separated, thus freeing the cell from the battery pack.

According to a third aspect of the invention there is provided a method for removing at least one cell from a battery pack comprising at least two cells that are arranged parallel to each other and are parallel to a given direction, and wherein the space between and/or around the cells comprises at least a polymeric-based filler compound, said method being characterised in that a mechanical pushing force is applied and/or transmitted to at least one cell, said mechanical pushing force being directed along said given direction and is configured to separate/eject said cell from the remaining part of the battery pack. Conveniently, the cell is ejected on one side that is opposite in respect to the one on which is applied said mechanical pushing force.

Preferably the method comprises disassembling at least a part of the battery pack prior to removing the at least one cell from the battery pack.

Preferably the method comprises removing and/or breaking electrical connections to the cells.

Preferably the method comprises removing and/or breaking electrical connections between the cells and one or more busbars of the battery pack.

Ideally the method comprises removing at least a part of the battery pack housing prior to removing the at least one cell from the battery pack Ideally the method comprises removing at least one of an upper clamshell and/or a lower clamshell from the battery pack. Advantageously, removing the upper and/or lower clamshell facilitates ejection of the cells since the upper clamshell and lower clamshell prevent longitudinal movement of the cells within the pack.

Preferably, said mechanical pushing force is configured to separate/eject said cell from the polymeric-based filler compound and/or from the sheathing means around said cell.

Preferably, said given direction corresponds to the longitudinal axis of said cells.

Preferably, the method comprising applying and/or transmitting said mechanical pushing force to a single cell along the longitudinal axis of said cell.

Preferably, the method comprising applying said mechanical pushing force in the range of about 20-100 N. Preferably, the method comprising applying directly said mechanical pushing force to the base of a single cell, preferably a flat base of said cell.

Preferably, the method comprising applying said mechanical pushing force to the base corresponding to and/or defining the negative electrode of said cell.

Preferably, the method comprising applying said mechanical pushing force in a continuous way or in a pulsating way to aid the mechanical ejection of the corresponding cell from the polymeric-based filler compound and/or from the sheathing means around said cell.

Ideally, the method comprising applying and/or transmitting an opposing mechanical pushing force to at least a part of the battery pack.

Ideally, the method comprising applying and/or transmitting the opposing mechanical pushing force in a direction which is substantially opposite the direction of the mechanical pushing force applied to the cell.

Preferably, the method comprising applying and/or transmitting the opposing mechanical pushing force by a reinforcement means.

Preferably the method comprises pushing the cell through a passage or aperture in the reinforcement means.

Preferably the method comprises pushing a plurality of cells through a plurality of passages or apertures in the reinforcement means.

Ideally, the method comprising applying and/or transmitting the opposing mechanical pushing force directly to the polymeric-based filler compound.

Preferably, the method comprising applying and/or transmitting said opposing mechanical pushing force so as to separate said polymeric-based filler compound and/or sheathing means from said cell.

Preferably, the method comprising applying and/or transmitting said opposing mechanical pushing force in the range of about 20-100 N. Preferably, the method comprising applying and/or transmitting said opposing mechanical pushing force in a continuous way or in a pulsating way to aid the mechanical separation of the polymeric-based filler compound and/or sheathing means from said cell Preferably, all the above-mentioned objects, taken individually and in any combination thereof, are achieved according to the invention by a machine for removing at least one cell from a battery pack comprising at least two cells that are arranged parallel to each other and are parallel to a given direction, and wherein the space between the cells comprises a polymeric-based filler compound, said machine being characterised in that it is configured to implement said method.

Ideally, said machine is configured to apply/transmit a mechanical force to at least one cell, said mechanical force being directed along said given direction and being configured to separate/eject said cell from the remaining part of the battery pack.

Preferably, said machine comprises pushing means configured to apply a force to a base of at least one cell, said force being directed along a longitudinal axis of said cell, so as to separate/eject said cell from the polymeric-based filler compound and/or from the sheathing means around said cell.

Preferably, said pushing means comprises at least one pusher rod or element facing and acting on a base of a corresponding cell to be separated/ejected from the remaining part of the battery pack.

Ideally, said pushing means comprises a plurality of parallel pusher rods or elements configured so that each pusher rod or element faces a corresponding base of a respective cell of the battery pack.

Preferably, said plurality of parallel pusher rods are activated and/or act on the respective cells at the same time or in sequence.

Preferably, said plurality of parallel pusher rods are mounted on the same supporting element that is actuated by a single actuator.

Preferably, said pushing means are actuated by a pneumatic, hydraulic or electronic 25 actuator.

Preferably, said pushing means are mounted on a moving structure controlled to position said pushing means in a condition facing the base of a corresponding cell to be separated/ejected from the remaining part of the battery pack.

Preferably, said moving structure comprises a robotic arm or gantry.

Preferably, the mechanical force that each pushing means applies to each cell is controlled and varied.

Preferably, the machine comprises mechanical force limiters to prevent that said pushing means apply excessive mechanical force to the end face of a cell, thus avoiding crushing or puncturing the cell which may result in cell venting.

Preferably, said machine comprises a collector for said at least one separated/ejected cell that is completely or substantially free of contamination or has dramatically reduced contamination and, in particular, is free of said polymeric-based filler compound and/or of said sheathing means. Conveniently, the cells so removed are then sent on to a high volume cell recycling process.

Preferably, said machine is controlled in an automated way.

The skilled person will appreciate that all preferred or optional features of the invention described with reference to only some aspects or embodiments of the invention may be applied to all aspects of the invention.

It will be appreciated that optional features applicable to one aspect of the invention can be used in any combination, and in any number. Moreover, they can also be used with any of the other aspects of the invention in any combination and in any number. This includes, but is not limited to, the dependent claims from any claim being used as dependent claims for any other claim in the claims of this application.

The invention will now be described with reference to the accompanying drawings which show by way of example only one embodiment of a battery pack and a method of separating components of a battery pack for recycling in accordance with the invention.

Figure 1 is a perspective view of a battery pack according to an aspect of the invention having a lower clamshell and wherein one cell is partially removed, Figure 2 is a perspective view of the battery pack of fig. 1 wherein one cell is completely removed, Figure 3 is a perspective view of a battery pack according to an aspect of the invention and a reinforcement plate according to a further aspect of the invention, Figure 4 is a different perspective view of the battery pack and reinforcement plate of fig. 3 Figure 5 is a perspective view of a reinforcement plate according to an aspect of the invention, Figure 6 is a perspective view of a machine acting on the battery pack and reinforcement plate of fig. 3 for removing a cell, Figure 7 is a perspective view of the battery pack and reinforcement plate of fig. 3 wherein one cell is partially removed by a corresponding pushing rod acting on said cell, Figure 8 is a lateral perspective view of the battery pack of fig. 7 wherein the pushing rod has just removed completely the cell from the corresponding battery pack. Figure 9 is a picture of a battery pack according to the invention, and Figure 10 is a cutaway view of a battery pack having a duct and filler material.

In Figure 1 there is shown a battery pack 1 that consists of a plurality of cells 2 that are arranged in an array pattern and that are encapsulated in a polymeric-based filler compound 3, such as polyurethane foam or silicone potting compound. In particular, the battery pack 1 comprises a substantially rigid assembly with a matrix of cells 2 that are arranged such that their longitudinal axes are parallel. The spaces between and around the side walls of cells 2 are filled with said polymeric-based compound 3. The cells 2 are contained between an upper plastic clamshell (not shown) and a lower plastic clamshell 4b which maintains the cell-to-cell spacing and pattern.

In one embodiment the polymeric-based filler 3 compound adheres directly to the sidewall of the cells 2, while in another preferred embodiment the cells 2 are covered by a thin external polymer sleeve 5 to prevent direct adhesion of the polymeric-based filler 3 to the metal sidewall of each cell 2.

Each sleeve 5 is suitable for the purposes of preventing the polymeric-based filler compound 3 adhering to the metal sidewall of each cell 2. Each external polymer sleeve 5 is provided on a respective cell 2 for the purposes of electrical insulation and short circuit protection between the positive and negative electrodes of said cell. Each external sleeve 5 is configured such that it does not overlap the end base 8 of the respective cell 2 which it surrounds. Where the polymeric-based filler 3 is directly adhered to the sleeves 5, rather than to the side walls of the cells 2, the amount of mechanical pushing force that needs to be applied longitudinally to each cell 2 in order to detach such a cell from the remaining part of the battery pack 1 is reduced.

The use of a polymeric-based filler compound 3, such as polyurethane foam or silicone, eliminates the need for a traditional adhesive to bond the cells 2 to the upper plastic clamshell (not shown) and/or lower plastic clamshell 4b, since the cured polyurethane foam or silicone provides sufficient mechanical rigidity to the assembly. The absence of a traditional glue such as methyl methacrylate adhesive (MMA) or other UV curing adhesive between the cells and the upper/lower clamshells is fundamental for the practical mechanical recovery of cells 2 from a fully assembled battery pack 1. Removing the requirement of gluing the cells to the upper and lower clamshells also makes it easier to remove the upper and lower clamshells during disassembly/recycling of the pack 1.

The battery pack 1 comprises a box-shaped frame 6 that lies between an upper plastic clamshell (not shown) and a lower plastic clamshell 4b. Each clamshell comprises a plurality of recesses, there being one recess for each cell of the battery pack 1. Each recess acts to receive and retain the base of a corresponding cell 2. Within each recess is an aperture through which electrical connections to the base of a cell can be made. Each aperture in the upper/lower clamshell provides an opening through which a force can be applied to an end base 8 of a cell 2 in order to push said cell 2 out of the frame 6.

The box-shaped frame 6 is a volume of polymeric-based filler compound 3 surrounding each cell. The frame 6 includes an array of holes 6a which accommodate each cell 2. In the present embodiment each cell 2 has a cylindrical shape with an external diameter of 18 mm and a length of 65 mm, or an external diameter of 21 mm and a length of 70 mm. Each cell 2 has two opposing bases that are substantially parallel with each other and are connected by a sidewall. Each cell 2 comprises a positive electrode on one base and a negative electrode located at the other base and on the sidewall.

During the cell recovery process, at least one of the upper and lower clamshells is removed in order to facilitate ejection of the cells 2. As will be understood by the skilled person, any electrical bonds such as wire bonds between the cells 2 and e.g. busbars on the upper and/or lower clamshell should also be removed and/or broken prior to disassembly of the battery pack 1.

Figure 3 shows the box-shaped frame 6 after the upper and lower 4b clamshells have been removed. The cells 2 are accessible via holes 6a. Figure 4 shows an alternative view to figure 3. In Figures 3 and 4 a reinforcement plate 7 has been placed on or attached to a face of frame 6 from which cells can emerge. The reinforcement plate 7 comprises a plurality of holes 7a which are arranged in a pattern that matches the pattern of cells 2 in the frame 6. Figure 5 shows the reinforcement plate 7 in detail. The reinforcement plate 7 comprises a body adapted to apply a force to a polymeric-based filler compound surrounding a cell and passages in the form of apertures 7a adapted to allow cells 2 to pass therethrough. The holes 7a in the reinforcement plate 7 are sized such that there is sufficient clearance for each cell 2 to be ejected (by applying a mechanical force along the longitudinal axis of each cell 2) and prevent snagging. The diameter of the holes 7a can range between about 18.25-19 mm for cells 2 having a diameter of 18 mm, and between about 21.25-22 mm for cells 2 having a diameter of 21 mm.

The purpose of the reinforcement plate 7 is to support the battery pack 1/frame 6 during the process of ejecting/recovering the cells 2. The cells 2 are held by the polymeric-based compound 3 acting as a filler in the space between said cells 2. A mechanical force is applied along the longitudinal axis of a cell 2 to push said cell through a hole 7a in the reinforcement plate 7. An opposing mechanical force is applied to the reinforcement plate 7 in order to push the frame 6/battery pack 1 in the opposite direction to the cells. The reinforcement plate 7 act to concentrate the applied force on the interface between the frame 6/filler 3 and the wall of a cell 2 causing them to decouple and separate, thus freeing the cell 2 from the pack 1.

Only the cells 2 can pass through the holes 7a in the reinforcement plate 7; the filler 3 is prevented from moving in the direction of the applied force by the body of the reinforcement plate 7 and the opposing mechanical force. In this way the reinforcement plate 7 aids in the separation of the cells 2 from the frame 6/filler 3. The reinforcement plate 7 also prevents any shearing of the filler 3 during ejection of the cells 2.

In embodiments where each cell 2 is surrounded by a polymer sleeve 5, the reinforcement plate 7 acts to concentrate the applied force on the interface between the polymer sleeve 5 and the wall of a cell 2 causing them to decouple and separate, thus freeing the cell 2 from the pack 1. As the skilled person will appreciate, a smaller force is required to separate a cell 2 from a sleeve 5 (to which the cell 2 is not adhesively bonded) than to separate a cell 2 from filler 3 to which the side wall of the cell 2 is directly bonded.

The method according to the invention for the removal/separation of a cell 2 from the remaining part of the battery pack 1 as defined above requires the application of a mechanical force -preferably in the range of 20-100 N -along the longitudinal axis of the cell 3, preferably on the base 8 defining the negative electrode as it is completely flat. In particular, the force can be applied in a continuous or pulsating way so as to aid in mechanical ejection of the cell 3. An opposing mechanical force -preferably in the range of 20-100 N -is applied to the reinforcing plate 7 in position while the cells 2 are being pushed through the plate.

The method may be implemented using a machine, such as the machine 10 shown in Figure 6. Machine 10 comprises an actuator, preferably a pneumatic actuator, with a pusher rod 11 mounted on a robotic arm 12 or gantry which can target individual cells 2 in the battery pack 1. The reinforcing plate 7 is mounted on e.g. a rigid surface and/or machine bed which provides the opposing mechanical force to prevent the battery pack 1/frame 6 from moving in the direction of the force applied by the pusher rod.

It is envisaged that this process is used in high volume cell recovery, for example, in automotive battery pack recycling. Advantageously, the machine 10 may comprise more parallel pusher rods 11 or a single large array of pusher rods mounted on the same bracket controlled by a single actuator, similar to a stamping die. Where the machine 10 includes a plurality of parallel pusher rods 11, in order to avoid the application of an excessive mechanical force on the end base 8 of a cell 2 (that could result in crush or puncture and cell venting), it is envisaged that the machine 10 includes mechanical force limiters to prevent the application of excessive force to a cell 2. The parallel pusher rods 11 can be activated and/or act on the respective cells 2 at the same time or in sequence.

Figure 7 shows the underside of the frame 6 and reinforcement plate 7 at the point where a cell 2 has been partially removed. Figure 8 is a side view of the frame 6 and reinforcement plate 7 at the point where a cell 2 has been completely pushed through an aperture in the reinforcement plate 7.

In the embodiment of the battery pack 1 wherein the cells 2 are surrounded by polymer sleeves 5 and wherein the polymeric-based filler compound 3 adheres/acts on the external surface of said polymer sleeves 5, the removal of a cell 2 by means of the method and machine 10 according to the invention is easier and cleaner since by applying the pushing force along longitudinal direction each cell 2 is detached from its corresponding polymer sleeve 5. As shown in figure 9, after cell removal the empty polymer sleeve 50 remains within the battery pack 1/frame 6 with polymeric-based filler compound 5 remaining on the outer surface thereof. Advantageously, the cells 2 so ejected are completely free of contamination and of any encapsulating polymeric-based filler compound 3.

In the embodiment of the battery pack 1 wherein the cells 2 are not covered by the polymer sleeve 5 and wherein the polymeric-based filler compound 3 adheres/acts directly on the external surface of said cells 2, the removal of a cell 2 by means of the method and machine 10 according to the invention requires more force and may leave some residue of filler 3 on the ejected cell 2.

After the cells 2 have been separated from the battery pack 1 they may be sent on to a high volume cell recycling process. The machine 10 is suitable to be used in such an automated high-volume recycling process.

From the above disclosure, the advantages of the battery pack according to this invention are apparent, since the use of potting compounds, such as silicone-based materials or polyurethane foam, significantly improves the protection against thermal propagation within a battery pack and have secondary benefits of improved vibration resistance and impact protection. At the same time, the battery pack can be readily disassembled to aid in recycling and cell recovery. In particular, the method and the machine according to the invention allow the mechanical removing/separation of each cell from the battery pack, thus allowing a proper recycling of the cell even if the use of the above potting compounds generally complicate, or substantially prevent, the commercial viability of recycling the battery pack at end of life. Indeed, polyurethane foam and silicone compounds have poor recycling characteristics and are generally subject to heat energy recovery (burning). Furthermore, the method and the machine according to the invention are easy to implement and avoid the significant cost that are usually required in the recycling process for the cleaning and other pre-processing steps. Last but not least, the method and the machine according to the invention allow to avoid the chemical dissolution process of the above mentioned potting polymeric-based compound, in particular considering that said process is costly, requires hazardous chemicals, is environmentally damaging and, furthermore, the required chemicals typically negatively interact with the cell, thus impeding any later recycling efforts.

Conveniently, the method and machine according to the invention may be used in all applications wherein the separation and/or recovery of the cells of/from a battery pack are required, for example of a battery pack used in electric vehicles.

The polymeric-based filler compound may be a solid or gelatinous compound or a thermo-setting plastic. The polymeric-based filler compound may comprise a silicone rubber gel, epoxy resin, polymeric foam, foam rubber or polyurethane foam.

Each cell may have a cylindrical or parallelepipedic shape and in the array, the cells may be aligned along at least one direction e.g. along two directions that are reciprocally orthogonal.

The battery pack 1 may comprise an inflatable thermal management system in the form of an inflatable thermal management duct 230 see Figure 10. The duct 230 is accommodated within the frame 6 and passes between one or more cells 2 in order to facilitate thermal management of the cells 2. The duct 230 may be inflatable and configured so that the force of the expanded duct 230 acts along a direction angled, preferably perpendicular, with respect to the longitudinal axis of each cell 2, thus maintaining the position and rigidity of the cell assembly. The duct 230 may be inflated using a pneumatic, hydrostatic or hydrodynamic force. In one embodiment, where the duct 230 is a flexible duct 230, the potting material 231 is provided adapted to act as a support for at least a part of the duct 230. Advantageously the flexible duct 230 can closely conform to the surface shape of the heat source/cells 2 within the pack 21 while being reinforced by the potting material 231 which acts to prevent the flexible duct 230 from over inflation and/or bursting.

The duct 230 is configured to carry the heat transfer fluid from an inlet to an outlet to transfer thermal energy between the heat source/cells 2 and the duct 230 at their engageable contact surfaces via the heat transfer fluid.

In relation to the detailed description of the different embodiments of the invention, it will be understood that one or more technical features of one embodiment can be used in combination with one or more technical features of any other embodiment where the transferred use of the one or more technical features would be immediately apparent to a person of ordinary skill in the art to carry out a similar function in a similar way on the other embodiment.

In the preceding discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of the said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The features disclosed in the foregoing description or the following drawings, expressed in their specific forms or in terms of a means for performing a disclosed function, or a method or a process of attaining the disclosed result, as appropriate, may separately, or in any combination of such features be utilised for realising the invention in diverse forms thereof as defined in the appended claims.

Claims

CLAIMS1. A method for removing at least one cell from a battery pack comprising at least two cells that are arranged parallel to each other and are parallel to a given direction, and wherein the space between and/or around the cells comprises at least a polymeric-based filler compound, said method being characterised in that a mechanical pushing force is applied and/or transmitted to at least one cell, said mechanical pushing force being directed along said given direction and is configured to separate/eject said cell from the remaining part of the battery pack.
2. A method as claimed in claim 1, wherein the method comprising ejecting the cell on one side that is opposite in respect to the one on which is applied said mechanical pushing force.
3. A method as claimed in any preceding claim, wherein the method comprises disassembling at least a part of the battery pack prior to removing the at least one cell from the battery pack.
4. A method as claimed in any preceding claim, wherein the method comprises removing and/or breaking electrical connections to the cells.
5. A method as claimed in any preceding claim, wherein the method comprises removing at least a part of the battery pack housing prior to removing the at least one cell from the battery pack and more particularly the method comprises removing at least one of an upper clamshell and/or a lower clamshell from the battery pack.
6. A method as claimed in any preceding claim, wherein said mechanical pushing force is configured to separate/eject said cell from the polymeric-based filler compound and/or from a sheathing means around said cell.
7. A method as claimed in any preceding claim, wherein the method comprising applying and/or transmitting said mechanical pushing force to a single cell along the longitudinal axis of said cell.
8. A method as claimed in any preceding claim, wherein the method comprising applying said mechanical pushing force in the range of about 20-100 N.
9. A method as claimed in any preceding claim, wherein the method comprising applying directly said mechanical pushing force to the base of a single cell, preferably a flat base of said cell.A method as claimed in any preceding claim, wherein the method comprising applying said mechanical pushing force to the base corresponding to and/or defining the negative electrode of said cell.11 A method as claimed in any preceding claim, wherein the method comprising applying said mechanical pushing force in a continuous way or in a pulsating way to aid the mechanical ejection of the corresponding cell from the polymeric-based filler compound and/or from the sheathing means around said cell.12 A method as claimed in any preceding claim, wherein the method comprising applying and/or transmitting an opposing mechanical pushing force to at least a part of the battery pack.13 A method as claimed in claim 12, wherein the method comprising applying and/or transmitting the opposing mechanical pushing force in a direction which is substantially opposite the direction of the mechanical pushing force applied to the cell.14 A method as claimed in claim 12 or 13, wherein the method comprising applying and/or transmitting the opposing mechanical pushing force by a reinforcement means.A method as claimed in claim 14, wherein the method comprises pushing the cell through a passage or aperture in the reinforcement means.16 A method as claimed in claim 14 or 15, wherein the method comprises pushing a plurality of cells through a plurality of passages or apertures in the reinforcement means.17 A method as claimed in any one of claims 12 to 16, wherein the method comprising applying and/or transmitting the opposing mechanical pushing force directly to the polymeric-based filler compound.18 A method as claimed in any one of claims 12 to 17, wherein the method comprising applying and/or transmitting said opposing mechanical pushing force so as to separate said polymeric-based filler compound and/or sheathing means from said cell.19 A method as claimed in any one of claims 12 to 18, wherein the method comprising applying and/or transmitting said opposing mechanical pushing force in the range of about 20-100 N. A method as claimed in any one of claims 12 to 19, wherein the method comprising applying and/or transmitting said opposing mechanical pushing force in a continuous way or in a pulsating way to aid the mechanical separation of the polymeric-based filler compound and/or sheathing means from said cell.21 A machine for removing at least one cell from a battery pack comprising at least two cells that are arranged parallel to each other and are parallel to a given direction, and wherein the space between the cells comprises a polymeric-based filler compound, said machine being characterised in that it is configured to implement said method as claimed in any one of claims 1 to 20.22 A machine as claimed in claim 21, wherein said machine is configured to apply/transmit a mechanical force to at least one cell, said mechanical force being directed along said given direction and being configured to separate/eject said cell from the remaining part of the battery pack.23 A machine as claimed in claim 21 or claim 22, wherein said machine comprises pushing means configured to apply a force to a base of at least one cell, said force being directed along a longitudinal axis of said cell, so as to separate/eject said cell from the polymeric-based filler compound and/or from a sheathing means around said cell.24 A machine as claimed in any of claims 21 to 23, wherein said pushing means comprises at least one pusher rod or element facing and acting on a base of a corresponding cell to be separated/ejected from the remaining part of the battery pack, said one or more of pusher rods are activated and/or act on the respective cells at the same time or in sequence, said one or more pusher rods are mounted on the same supporting element that is actuated by a single actuator.A machine as claimed in any of claims 21 to 23, wherein said pushing means are mounted on a moving structure controlled to position said pushing means in a condition facing the base of a corresponding cell to be separated/ejected from the remaining part of the battery pack, said moving structure comprises a robotic arm or gantry.