GB2612085A

GB2612085A - Cell carrier and method of securing cells to carrier

Info

Publication number: GB2612085A
Application number: GB2115141.0A
Authority: GB
Inventors: Rajamani Jayaprakash; Roberts Ian
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2023-04-26
Also published as: GB202115141D0

Abstract

A method of securing a plurality of electrical cells (100, figures 3A-B) in a cell carrier (200, figure 2A) is provided. At least one bead of adhesive is provided in a groove 212 in each of the cell location features 202, and an end of each of the cells is pushed into a corresponding cell location feature. The beads of adhesive are then cured. Each cell location feature is provided with an aperture (204, figure 2B) enabling access to the ends of the electrical cells through the cell carrier. In some embodiments, the grooves have a tapered profile that helps to direct the adhesive in a radially outward direction. Preferably, the cell carrier is at least partially translucent and the adhesive is a light-curing adhesive, so that the beads of adhesive may be cured by applying light of a predetermined wavelength through the cell carrier, after assembly of the cells within the cell carrier. A similar cell carrier may be provided at the opposite ends of the cells. A battery module comprising a plurality of cells attached to the cell carrier(s) and a battery pack comprising a plurality of such modules are also disclosed.

Description

Cell Carrier And Method Of Securing Cells To Carrier

TECHNICAL FIELD

The present invention relates generally to cell carriers methods for securing cells to a cell carrier. In particular, but not exclusively, the invention relates to methods for connecting a group of cells to a cell carrier for incorporation into a battery module of a vehicle. Aspects of the invention relate to a method, to a cell carrier, to a battery module, to a battery pack, and to a vehicle.

INTRODUCTION

There has recently been increased interest in providing battery-powered vehicles, which has led to developments in vehicle battery, in particular vehicle traction battery technology. In the manufacture of vehicle traction batteries, it is known for a plurality of electrical cells to be housed within one or more housings or carriers. It is also known for cells to be electrically connected to a busbar assembly by welding the end surfaces of the cells to a portion of the busbar assembly.

Accordingly, it is important to ensure secure connection of cells to their housings, without contaminating the surfaces that are to be welded to the busbar assembly. The present invention aims to at least partially mitigate one or more problems with the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the invention for which protection is sought, there is provided a method of securing a plurality of electrical cells to a first cell carrier, wherein the first cell carrier comprises: a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier, wherein the method comprises: applying a bead of adhesive into at least one of the grooves associated with each cell location feature on the first cell carrier; positioning an end of a respective cell into each cell location feature on the first cell carrier, such that the end of each cell contacts the bead of adhesive in the groove of the cell location feature; and curing the beads of adhesive. Advantageously, the grooves help to guide the adhesive in a radially outward direction when the cells are pushed into the location features. This also results in some of the adhesive moving up the cylindrical surface of the cell. Guiding the adhesive in this way helps to prevent adhesive from fouling the surfaces of the cells that are to be subsequently welded to busbar components, and increases the area covered by the adhesive, thereby strengthening the bond between the cells and the carrier.

In an embodiment, the method comprises: providing a first fixture having at least one datum surface configured to locate the cell carrier; and positioning the first cell carrier in contact with the datum surface. Advantageously, this ensures that the carrier is substantially flat when the cells are pushed into the location features.

In an embodiment, the cell carrier is at least partially translucent and the adhesive is light-curing adhesive, wherein the step of curing the beads of adhesive comprises applying light of a predetermined wavelength to the adhesive through the cell carrier.

In an embodiment, the method comprises providing a second cell carrier (400), the second cell carrier comprising: a plurality of cell location features (402), each cell location feature arranged to receive an end of a respective electrical cell; at least one groove (412) associated with each cell location feature; and one or more apertures (404) enabling access to the ends of the electrical cells through the cell carrier, wherein the method comprises: applying a bead of adhesive into at least one of the grooves associated with each cell location feature on the second cell carrier; and positioning the second cell carrier onto the ends of the cells distal from the first cell carrier, such that an end of each cell contacts the bead of adhesive in the groove of the cell location feature. Advantageously, providing first and second cell carriers improves the overall rigidity of the connected cells and carriers. Furthermore, a substantial portion of the cells may be covered by the first and second carriers, reducing a risk of foreign objects contacting the cells and potentially causing a short circuit. Indeed, in some embodiments, the first and second carriers may have upstanding portions which contact each other when both cell carriers are in place, such that the cells are fully enclosed, save for the apertures in the cell location features, when the carriers are in place.

In an embodiment, the method further comprises providing a clamping fixture, and positioning the clamping fixture in contact with the second cell carrier when the first cell carrier is in contact with the first fixture. Advantageously, the clamping fixture helps to ensure that the second cell carrier is flat and securely positioned on the cells.

In an embodiment, the clamping fixture is translucent. Advantageously, this allows the adhesive to be cured by directing light through the clamping fixture and the second cell carrier.

In an embodiment, the cells comprise a positive terminal at least partially defined on a first end of the cell and a negative terminal at least partially defined on a second end of the cell, wherein the second ends of the cells are positioned into the location features on the first cell carrier. Alternatively, the cells may be oriented in the opposite direction. Advantageously, orienting all of the cells in the same direction simplifies the welding process.

In an embodiment, the cell location features comprise an annular surface arranged to abut a peripheral region of an end surface of the cell and a second surface upstanding from the annular surface, wherein at least part of the second surface is arranged to abut a cylindrical surface of the cell. Advantageously, this increases the area over which adhesive can join the cells to the carriers, because the adhesive may join the second surfaces of the carriers to the cylindrical surfaces of the cells. Optionally, the second surface is a substantially cylindrical surface. Further optionally, the grooves are disposed in the annular surfaces of the location features In an embodiment, the grooves are tapered along their length, such that the grooves have a first depth at a first position and a second depth greater than the first depth at a second position spaced apart from the first position. In an embodiment, the first position is located on the annular surface at a radially inside end of the groove. Advantageously, this ensures that the adhesive is directed towards the cylindrical surface, thereby avoiding contaminating the surface of the cell that is to be electrically connected to a busbar component, and increasing the contact area that is joined by the adhesive.

Optionally, the first and second positions are first and second groove ends.

In an embodiment, two grooves are provided for a plurality of the location features. It will be understood that some location features, especially those located at the outside edges of the carrier, may only have one groove, even in embodiments in which the majority of the cell location features have two grooves.

In an embodiment, each of the grooves extends along approximately 15-35% of the circumferential length of the annular surface. Preferably, the grooves may each extend around 25% of the circumferential length of the annular surface. Advantageously, this provides a flat surface around 50% of the circumferential length for cell location features having two grooves.

It also helps to control the depth of the adhesive when it is uncured.

According to another aspect of the invention for which protection is sought, there is provided a cell carrier comprising: a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier, wherein the grooves are tapered along their length, such that the grooves have a first depth at a first end thereof and a second depth greater than the first depth at a second end thereof Such a cell carrier may be used in a method as described above.

In an embodiment, the cell location features comprise an annular surface arranged to abut a peripheral region of an end surface of the cell and a second surface upstanding from the annular surface, wherein at least part of the second surface is arranged to abut a cylindrical surface of the cell.

In an embodiment, the second surface is a cylindrical surface.

In an embodiment, the grooves are disposed in the annular surfaces of the location features.

According to an aspect of the invention for which protection is sought, there is provided a battery module comprising a plurality of electrical cells connected to a cell carrier produced by a method as described above, or a cell carrier as described above.

According to an aspect of the invention for which protection is sought, there is provided a battery pack comprising a plurality of battery modules as described above.

According to an aspect of the invention for which protection is sought, there is provided a vehicle comprising a battery module as described above and/or a battery pack as described above.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only, with reference to the accompanying figures, in which: Figures 1A-C show different views of a cylindrical cell that may be used in a vehicle battery module (PRIOR ART); Figure 2A shows a cell carrier having a plurality of cell location features in an embodiment of the present invention; Figure 2B shows an enlarged view of one of the cell location features of the cell carrier shown in figure 2A; Figure 2C shows a cross section view along line A-A in figure 2B Figure 3A shows a cross section through a cell in the cell carrier shown in figure 2; Figure 3B shows an enlarged view of a portion of figure 3A; Figure 4A shows a group of cells connected to first and second cell carriers in an embodiment of the present invention; Figure 4B shows an exploded view of the cell carriers and a subset of the cells in the arrangement shown in figure 4A; Figure 5 shows a first fixture and a clamping fixture containing a set of cells within first and second cell carriers; Figure 6 shows a flow chart illustrating a method in an embodiment of the present invention; and Figure 7 shows a vehicle in an embodiment of the present invention.

DETAILED DESCRIPTION

Figures 1A-C show different views of a conventional cylindrical cell 100. Cylindrical cells 100 are widely available in a variety of different sizes. For example, in traction batteries for vehicles cells haying a diameter D of 21mm and a length L of 70mm are often used. Such cells are typically referred to as 21700 cells (the first two numbers referring to the diameter D, in mm, and the last three numbers referring to the length L, in tenths of mm). However, it will be understood that other sizes of cell may also be used in embodiments of the present invention.

As will be well understood by the skilled person, the cell 100 comprises a positive terminal 100P, a negative terminal 100N, and vent means 100V. The positive terminal is provided by a steel end cap 106 in a central region of the first end 104 of the cell, and the negative terminal is provided by a steel cylindrical case 108. The steel cylindrical case 108 covers the second end 102, the entire cylindrical surface between the first and second ends, and a peripheral region 100S of the first end surface. The peripheral region of the first end surface may also be referred to as a "shoulder" region 1005 of the first end surface 104. In commercially-available cells, it is sometimes the case that the end cap that defines the positive terminal 100P on the first end surface 104 protrudes beyond the shoulder region of the first end surface, although this is not the case in the cell shown in figure 1. This allows a substantially planar connector to be connected to the positive terminal and not the negative terminal. As will be well understood by the skilled person, it is important to avoid direct electrical connections between the positive and negative terminals, as such connections create a short circuit which may damage the cell.

As shown in figure 1, the cell 100 comprises three vent means 100V in the first end surface 104, between the steel end cap 106 that defines the positive terminal 100P and the shoulder region 100S of the steel cylindrical case 108. The vent means 100V are gaps that are covered by a material that will rupture to allow hot gases to escape through the gap between the end cap 106 and steel cylindrical case 108 in the event of excessive pressure occurring inside the cell, thereby mitigate against the risk of the cell exploding.

According to embodiments of the present invention, there are provided methods of welding a tab of a busbar component to a terminal of an electrical cell, especially to a terminal of a cylindrical cell, battery packs and battery modules produced by welding such tabs to terminals of electrical cells, and vehicles including such battery packs. In all cases, the cells may comprise cells as described above. The cells may have a negative terminal made from a steel cylindrical case having a thickness of approximately 0.22mm in the cylindrical region, for example 0.1-0.3mm. The bottom and shoulder regions of the case may have a thickness of approximately 0.4mm, for example 0.3-0.5mm. The positive terminal may also have a thickness of approximately 0.4mm, for example 0.3-0.5mm. Both terminals may include a nickel plating, which may have a thickness of approximately 2-5 microns.

Figure 2A shows a cell carrier 200 in an embodiment of the present invention. Cell carrier 200 comprises a plurality of cell location features 202. An aperture 204 is provided in each cell location feature. The cell location features are arranged in four rows 206A-D in the embodiment shown in figure 2A, with each row being offset from the adjacent rows by half the distance between the centrelines of adjacent cell location features. This helps to improve packaging efficiency of the cells 100 when they are placed into the cell location features 202.

As will become apparent from the following description, the cell carrier 200 is configured to receive a cylindrical cell in each of the cell location features 202. The cells may then be electrically connected to a suitable busbar assembly via the apertures 204, so as to create a "supercell" comprising a plurality of cells electrically connected to one another.

In some embodiments, all of the cells may be electrically connected to one another in parallel. However, in alternative embodiments, the cells may be connected as several groups, wherein the cells within each group are connected in parallel, and each group is connected in series with the other groups. This is typically the case as it allows a suitable combination of voltage and charge/current capacity to be provided. If several such groups are present within the same cell carrier, then the orientation of the cells could alternate between adjacent groups, to facilitate making series connections between the adjacent groups. However, the present inventors have recognised that it may be preferable to provide series connection portions passing around the sides of the group of cells to make the series connections between adjacent groups. This allows all of the cells to be oriented in the same direction, so that the welding operations on one side of the group of cells are all connecting a positive terminal of one of the cells to a busbar component and the welding operations on the other side all connect a negative terminal of one of the cells to a busbar component. Furthermore, orienting the cells in the same direction allows protection against vent gases to be provided only on one side of the group of cells. In all events, it will be understood that it is very important to ensure that no electrical contact other than that required for creating series connections occurs between cells in different groups, as such contact could cause a short circuit.

The cell carrier 200 also includes an upstanding edge portion, which partially covers the cylindrical surfaces of the outermost cells within the carrier, thereby helping to prevent external objects from contacting the cells, which could cause a short circuit.

Figure 2B shows an enlarged view of one of the cell location features 202. As shown in figure 28, the cell location feature comprises an annular abutment surface 208, and a plurality of upstanding portions 210. The annular abutment surface 208 is sized so as to allow a peripheral region of an end surface of a cell 100 to abut the surface when the cell is pushed into the location feature 202. Similarly, the upstanding portions are positioned such that they at least partially engage a portion of the cylindrical surface of a cell pushed into the location feature. In the illustrated embodiment, the cell location features 202 are sized to accept the ends of 21700 cells, although it will be understood that the invention could readily be adapted to other types of cylindrical cells, or to non-cylindrical cells. The cells may be retainable within the location features by a friction fit. However, the cells will typically be firmly retained within the location features 202 by adhesive, which may be applied into two tapered grooves 212 within the location feature before insertion of the cells.

Referring again to figure 2A, it can be seen that the grooves 212 are substantially aligned with direction of the rows of cells. As will be discussed in more detail below, this reduces the number of passes required for an adhesive dispensing machine to apply adhesive in all of the grooves.

As shown in figure 2C (not to scale), the depth of the tapered grooves 212 increases from substantially zero at the radially inside end of the groove to a depth D at the radially outermost end of the groove (i.e. the end adjacent to the upstanding portion 210). The depth increases in a generally linear manner between the radially inner and outer ends of the groove. In the illustrated embodiment, the depth D is approximately 0.5mm. However, it will be understood that in other embodiments the depth may be different. Similarly, the depth at the radially inside end of the groove may not be zero in some embodiments, and the groove profile between the inner and outer ends may be non-linear in some embodiments. In one embodiment, the depth D at the radially outermost end may be 0.5mm and the depth at the radially inside end may be 0.2mm.

It will understood that the tapered grooves 212 help to direct the adhesive in a radially-outward direction because the pressure at the surface of the groove has a component acting in the radially-outward direction. Furthermore, as the cell is pushed into the location feature, the gap between the end of the cell and the location feature is smaller at the radially-inside end of the groove than the radially-outer end of the groove. This increases the resistance to flow of the adhesive in the radially-inward direction, as compared to flow in the radially-outward direction.

Figure 3A shows the insertion of a cell 100 into a cell location feature 202 of a cell carrier 200. In the embodiment illustrated in figure 3A, the second end 102 of the cell is inserted into the cell location feature 202 by pushing the cell in a longitudinal direction, as illustrated by arrow 300, until a peripheral portion of the second end surface of the cell abuts the annular abutment surface 208. Although only one cell 100 and corresponding cell location feature 202 is illustrated in figure 3A, it will be understood that a cell will typically be inserted into each of the cell location features in the cell carrier 200. Furthermore, prior to insertion of the cells, an adhesive will typically be inserted into each of the tapered grooves. As the cell 100 is inserted into the cell location feature 202, the adhesive spreads to form a large contact area between the cell and the cell location feature, thereby providing a strong bond once the adhesive is cured. It should be noted that the grooves 212 are not visible in figure 3A, because the cross section is taken on a plane that does not include the grooves 212.

Pushing the cell into the cell location feature also has the effect of compressing the cell carrier 200 against a datum surface 302 of a first fixture 300. It will be understood that the cell carrier 200 may be made from a moulded plastics material, and as such may have a significant degree of flexibility, and may not be manufactured to a very precise dimensional tolerance. It is therefore advantageous to provide a first fixture 300 having a flat datum surface, which may be machined to a precise tolerance, to ensure that the cell carrier 200 is flat when the cells 100 are inserted into the cell location features. This may be particularly important in embodiments in which the subsequent electrical connection of the cells to one or more busbar components is to be done by laser welding, as it is beneficial for the surfaces to be laser welded to be in substantially the same plane as each other.

A particular advantage of the tapered groove profiles shown in figure 2C is that they help to direct the adhesive in a radially-outward direction. Accordingly, if more adhesive is provided than would be needed to fill the grooves 212, then a portion of the adhesive will be forced up into the annular gap between the upstanding portions 210 and the cylindrical surface of the cell 100, thereby increasing the area over which the adhesive connects the cell to the location feature 202.

Any suitable adhesive may be used to connect the cells 100 to the cell location features 202.

However, in the illustrated embodiment, the adhesive is a UV cure adhesive. Accordingly, the cell carrier 200 is at least translucent to UV light, so that the adhesive may be cured in a UV cure nest, as will be discussed in more detail below.

Although figures 3A and 3B show only one end of the cell 100 being inserted into a cell carrier 202, in some embodiments both ends of the cells may be inserted into respective first and second cell carriers, as shown in figures 4 and 5.

Figure 4A shows an enclosed group of cells 401 comprising a first cell carrier 200 in which one end of the cells is held, and a second cell carrier 400 into which the opposite end of the cells is held. The second cell carrier is similar to the first cell carrier, and the same reference numerals, but increased by 200, will be used to refer to parts of the second cell carrier.

As can be seen from figure 4A, the cell carriers each have an upstanding edge portion, 214, 414, which portions contact each other such that the cells are enclosed on all sides and are only accessible via the apertures 204, 404, thereby protecting the cylindrical surfaces of the cells and preventing external objects from causing short circuits.

Figure 4B shows an exploded view of the components shown in figure 4A. As will be discussed in more detail below, the enclosed group of cells is manufactured by first applying beads of adhesive 422 into the grooves in the first cell carrier 200, then inserting an end of each of the cells 100 into the cell location features 202 in the first carrier 200, with the first cell carrier 200 located on top of a fixture having a flat datum surface. Beads of adhesive 420 are also applied into the grooves 412 in the cell location features 402 of the second cell carrier 400, and the second cell carrier is then pushed onto the exposed ends of the cells 100 until the upstanding edge portions 214, 414 contact each other. A second fixture having a second flat datum surface may then be placed on top of the second cell carrier 400, to ensure that the second cell carrier is flat before the adhesive cures.

It will be understood that the beads of adhesive 420, 422 are illustrated as elongate cylinders for ease of illustration, and that the beads of adhesive will actually conform to the surface on which they are applied. However, it is a particular advantage of the positioning of the grooves in the embodiment shown in the illustrated embodiments that the adhesive can be applied into all of the grooves by providing four elongate beads of adhesive, which will flow into all of the grooves. This can reduce the overall time taken to assemble the group of cells 401.

In the embodiment illustrated in figure 4, the first ends of the cells (i.e. the ends at which the positive terminals are located) are located in the cell location features of the second carrier 400, and the second ends of the cells are located in the cell location features of the first carrier 200. However, it will be understood that this may be the other way around. Furthermore, in some embodiments some of the cells may have their first end located in the first carrier 200 and others may have their second end located in the first carrier 200.

Figure 5 shows the assembled enclosed group of cells 401 inside a UV cure nest 500. The UV cure nest 500 comprises the first fixture 300 and a clamping fixture 502. Both the first fixture 300 and the clamping fixture 502 comprise a flat datum surface arranged to ensure that the surface of the carrier abutting the respective datum surface is also flat.

To manufacture the group of enclosed cells 401, the first cell carrier 200 is placed on top of the first fixture 300. A bead of adhesive is applied into each of the grooves 212 in the cell location features 202 on the first fixture. The beads of adhesive may be applied with the first carrier 200 already in place on the first fixture 300, or they may be applied in a separate apparatus prior to placing the cell carrier onto the first fixture. In the illustrated embodiment, the adhesive is a UV cure adhesive, which advantageously allows the curing to take place at a selected time by the application of UV light to the uncured adhesive. However, it will be understood that in alternative embodiments different types of adhesive may be used.

A particular advantage of providing grooves 212 that are substantially aligned with one another and the longitudinal axis of the cell carrier is that this simplifies the application of the beads of adhesive. This is because a dispensing nozzle (not shown) may move along the longitudinal axis of the cell carrier 200 and dispense a bead of adhesive into each groove within a row of grooves. Accordingly, all of the required beads of adhesive may be deposited by a single dispensing nozzle making ten substantially straight passes over the cell carrier 200 in the longitudinal direction. Preferably however, a dispensing head comprising ten connected nozzles may dispense all of the required beads of adhesive in a single pass along the cell carrier 200 in the longitudinal direction.

After the beads of adhesive are in place, the second ends of a cell 100 is pushed into each of the cell location features 202, until a peripheral region of the second end surface abuts the annular abutment surface 208. This causes the beads of adhesive to be compressed and fill the grooves. Because of the tapered shape of the grooves 212, excess adhesive is also directed out of the groove and into the gap between the cylindrical surface of the cell and the upstanding portions 210 of the cell location features 202. This helps to increase the contact area of the adhesive joining the cells to the cell carrier 200, which helps to improve the stiffness and strength of the finished group of enclosed cells 401. Furthermore, directing the adhesive outwardly towards the cylindrical surfaces of the cells rather than inwardly towards the central portion of the cell end surface helps to prevent contamination of the cell end surface, which will typically be electrically connected to a busbar component once the group of enclosed cells 401 is completed.

Beads of adhesive are also applied into the grooves 412 on the second cell carrier 400. These beads of adhesive may be applied in a similar manner to the beads of adhesive applied to the first cell carrier 200. The second cell carrier is then placed on top of the exposed first ends 104 of the cells, and pushed down so that each of the first ends is located in a respective one of the cell location features 402 on the second cell carrier 400. Again, the grooves 412 help to spread the adhesive into the gap between the cylindrical surface of the cells and the upstanding portions 410, which increases the contact area of the adhesive and helps to prevent contamination of the surfaces of the cell that are to be electrically connected to busbar components.

The clamping fixture 502 is then placed on top of the second cell carrier 400 and secured in place with bolts or other suitable fixings (not shown). The clamping fixture is held in place sufficiently firmly to ensure that the surface of the cell carrier 400 that abuts the clamping fixture assumes the flat profile of the datum surface of the clamping fixture. At this stage, the cells are all held in place and the first and second cell carriers are prevented from flexing to make their outside surfaces non-flat. The adhesive is then cured by the application of a UV light source of a predetermined intensity to the UV cure nest 500 for a predetermined length of time. To facilitate the application of the UV light, the first and second cell carriers, the first fixture and the clamping fixture are all made from materials that are at least translucent to UV light. After the curing of the adhesive is finished, the group of enclosed cells 401 is complete, and may be used in downstream manufacturing processes.

Advantageously, manufacturing the group of enclosed cells 401 in the manner described improves the stiffness of the group of enclosed cells, because the contact area of the adhesive is increased. Furthermore, the risk of contamination of the central portions of the end surfaces of the cells is substantially reduced.

Figure 6 shows a flow chart illustrating a method 600 for securing a plurality of cells to a cell carrier in an embodiment of the present invention. The method 600 starts at step 602 with the provision of a cell carrier having a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier. The method then proceeds to step 604, in which a bead of adhesive is applied into at least one of the grooves associated with each cell location feature on the cell carrier. The method then proceeds to step 606, in which an end of a respective cell is positioned into each cell location feature on the first cell carrier, such that the end of each cell contacts the bead of adhesive in the groove of the cell location feature. The method then proceeds to step 608, in which the beads of adhesive are cured, and then ends.

In some embodiments, the beads of adhesive may be light-cured beads of adhesive, for example beads of UV cured adhesive. Accordingly, step 608 may comprise curing the beads of adhesive by exposing them to light of a predetermined wavelength, for example UV light.

To this end, the cell carrier may be at least partially translucent.

Figure 7 shows a vehicle 700 into which a cell carrier, plurality of cells secured to one or more cell carriers, a battery module or a battery pack comprising a plurality of battery modules produced according to one or more of the above embodiments may be incorporated. In the illustrated embodiment, a battery pack 702 including four battery modules 704 is incorporated into the vehicle 700.

Claims

CLAIMS1. A method of securing a plurality of electrical cells to a first cell carrier, wherein the first cell carrier comprises: a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier, wherein the method comprises: applying a bead of adhesive into at least one of the grooves associated with each cell location feature on the first cell carrier; positioning an end of a respective cell into each cell location feature on the first cell carrier, such that the end of each cell contacts the bead of adhesive in the groove of the cell location feature; and curing the beads of adhesive.
2. A method as claimed in claim 1, wherein the method comprises: providing a first fixture having at least one datum surface configured to locate the cell carrier and positioning the first cell carrier in contact with the datum surface.
3. A method as claimed in any preceding claim, wherein the cell carrier is at least partially translucent and the adhesive is light-curing adhesive, wherein the step of curing the beads of adhesive comprises applying light of a predetermined wavelength to the adhesive through the cell carrier.
4. A method as claimed in any preceding claim, comprising providing a second cell carrier, the second cell carrier comprising: a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier, wherein the method comprises: applying a bead of adhesive into at least one of the grooves associated with each cell location feature on the second cell carrier; and positioning the second cell carrier onto the ends of the cells distal from the first cell carrier, such that an end of each cell contacts the bead of adhesive in the groove of the cell location feature.
5. A method as claimed in claim 4 where dependent through claim 2, wherein the method further comprises providing a clamping fixture, and positioning the clamping fixture in contact with the second cell carrier when the first cell carrier is in contact with the first fixture.
6. A method as claimed in any preceding claim, wherein the cells comprise a positive terminal at least partially defined on a first end of the cell and a negative terminal at least partially defined on a second end of the cell, wherein the second ends of the cells are positioned into the location features on the first cell carrier.
7. A method as claimed in any preceding claim, wherein the cell location features comprise an annular surface arranged to abut a peripheral region of an end surface of the cell and a second surface upstanding from the annular surface, wherein at least part of the second surface is arranged to abut a cylindrical surface of the cell.
8. A method as claimed in claim 8, wherein the second surface is a substantially cylindrical surface.
9. A method as claimed in claim 7 or claim 8, wherein the grooves are disposed in the annular surfaces of the location features.
10. A method as claimed in any preceding claim, wherein the grooves are tapered along their length, such that the grooves have a first depth at a first position and a second depth greater than the first depth at a second position spaced apart from the first position.
11. A method as claimed in preceding claim 10, wherein the first position is located on the annular surface at a radially inside end of the groove.
12. A method as claimed in any preceding claim, wherein two grooves are provided for a plurality of the location features
13. A method as claimed in claim 12 wherein each of the grooves extends along approximately 15-35% of the circumferential length of the annular surface.
14. A cell carrier comprising: a plurality of cell location features, each cell location feature arranged to receive an end of a respective electrical cell; at least one groove associated with each cell location feature; and one or more apertures enabling access to the ends of the electrical cells through the cell carrier, wherein the grooves are tapered along their length, such that the grooves have a first depth at a first end thereof and a second depth greater than the first depth at a second end thereof.
15. A cell carrier as claimed in claim 14, wherein the cell location features comprise an annular surface arranged to abut a peripheral region of an end surface of the cell and a second surface upstanding from the annular surface, wherein at least part of the second surface is arranged to abut a cylindrical surface of the cell.
16. A cell carrier as claimed in claim 15, wherein the second surface is a cylindrical surface.
17. A cell carrier as claimed in claim 15 or claim 16, wherein the grooves are disposed in the annular surfaces of the location features.
18. A battery module comprising a plurality of electrical cells connected to a cell carrier produced by a method as claimed in any one of claims 1-13 or a cell carrier as claimed in any one of claims 14-17.
19. A battery pack comprising a plurality of battery modules as claimed in claim 18.
20. A vehicle comprising a battery module as claimed in claim 18 and/or a battery pack as claimed in claim 19.