GB2611782A

GB2611782A - Voltage measurement connector

Info

Publication number: GB2611782A
Application number: GB2114677.4A
Authority: GB
Inventors: Trigg Robert; Roberts Ian; Hoss Leonardo
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2023-04-19
Anticipated expiration: 2041-10-14
Also published as: GB202114677D0; GB2611782B; WO2023062230A1

Abstract

A voltage measurement connector 100 for a battery module of an electric vehicle comprises a conductive sheet shaped to provide: a flat central panel 102 with a pair of guide edges 104a, 104b and a clip end 106 between the pair of guide edges; a resilient clip portion 112 to fit over an end of a connection tab (200, figure 2) of a busbar of the battery module; and a pair of guide tabs 110a, 110b, located on the guide edges, to guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion. There may also be a lip 122 on the clip portion to aid installation. After sliding on to the connector tab, the connector may be laser welded in place. Several such connectors may be attached to a harness to measure cells within a battery module. The connector may be formed by bending a metal sheet into shape.

Description

Voltage Measurement Connector

TECHNICAL FIELD

The present invention relates generally to measurement of electrical parameters of a battery. In particular, but not exclusively, the invention relates to a voltage measurement connector for use with a battery module used as a vehicle traction battery, for example for a Battery Electric Vehicle (BEV). Aspects of the invention relate to voltage measurement connectors, harness assemblies, battery module assemblies, battery packs, methods of forming a voltage measurement connector and methods of forming an electrical connection to a module busbar.

BACKGROUND

There has recently been increased interest in providing battery-powered vehicles, which has led to developments in vehicle batteries, in particular vehicle traction battery technology.

Vehicle traction batteries often comprise one or more modules each containing a plurality of cells. It is desirable to be able to monitor the voltage over the modules and batteries in a simple and reliable way. Further, due to the nature of battery packs used in vehicles, any electrical connections made to the battery need to be robust and secure in order to withstand repeated movements due to the vehicle being driven (e.g. vibrations, shocks and bumps).

From a manufacturing and design point of view, it is desirable to provide a simple way of forming an electrical connection to a battery module busbar, and one which does not require complex or additional manufacturing steps to be employed to form the connections. Furthermore, it is desirable for such connections to be made while maintaining a compact battery design i.e. by making a good use of space.

Thus, there is a need to provide easy to manufacture, reliable and structurally sound battery connections, for example for voltage monitoring, for battery packs of electric vehicles.

SUMMARY OF THE INVENTION

According to an aspect of this disclosure, there is provided a voltage measurement connector for a battery module of an electric vehicle, the voltage measurement connector comprising a conductive sheet shaped to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end, the resilient clip portion configured to fit over an end of a connection tab of a module busbar of a battery module in resilient gripping engagement therewith; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges, the pair of guide tabs configured to be located along opposite edges of the connection tab and, in use, guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion.

The resilient clip portion may advantageously bias the flat central panel of the connector towards the connection tab, so as to contact the connector with the connection tab, without the need for an external clamping mechanism acting to bias the connector and connection tab together.

The resilient clip portion may be configured to fit over a flat elongate connection tab. The flat central panel may comprise an inner surface and an outer surface, and the resilient clip portion and the pair of guide tabs may be located on the same side of the flat central panel towards the inner surface.

The pair of guide tabs may be parallel and may each have a tab plane perpendicular to a plane of the flat central panel. In this way, axial rotation of the connector in the plane of the connection tab is mitigated against when the connector is being located on the connection tab, thereby making it easy to slot the connector onto the connection tab.

The resilient clip portion may comprise an end portion configured to fit over the end of the connection tab. The end portion may have an end lip angled away from the flat central panel to facilitate sliding the voltage measurement connector onto the connection tab The voltage measurement connector may be configured to be slid onto the connection tab and then welded (e.g. laser welded) onto the connection tab. The flat central panel of the connector, at an end distal from the clip end, may be configured to be laser welded onto the connection tab. In this way, the electrical connection of the connector to the connection tab is made in a robust way, so that it will not become easily disconnected, for example due to a vehicle containing the battery being used, which causes vibrations and shocks/bumps to the battery as the vehicle is driven.

An inner surface of the flat central panel of the connector may be configured to, in use, lie coplanar with and adjacent to a flat face of the connection tab to which the connector is connected. This arrangement of connection tab surface in contact with the voltage measurement connector inner surface, the surfaces being biased together by the resilient clip portion, may facilitate laser welding the two together, for example without the need for external clamping means biasing the two together to allow for a secure weld to be formed.

The voltage measurement connector may comprise a connecting wire attached to the conductive sheet, for example to the outer surface of the connector. The connecting wire may be configured to provide (e.g. voltage monitoring) electrical signals from the attached connection tab to a controller. The connecting wire may be attached to the flat central panel of the conductive sheet at an end proximal to the clip end. The connector may be configured to be attached to the connecting wire by a soldered connection The conductive sheet of the voltage measurement connector may comprise nickel coated copper. Copper provides good electrical conductivity. Nickel helps to reduce any corrosion to the connector. The conductive sheet may have a thickness of between 150 microns and 500 microns; such as between 200 microns and 400 microns; preferably about 300 microns. The connector may have a width dimension between the pair of guide edges of between 3mm and 10mm; preferably between about 6mm and 7mm. The connector may have a length dimension between an edge proximal to the clip end and an opposite edge opposite to the clip end of between 8mm and 20mm, such as between lOmm and 13mm, e.g. 11.5mm.

In a further aspect there is provided a harness assembly for a battery module of an electric vehicle, comprising: at least one voltage measurement connector as described herein; and an electrically conductive track electrically connected to the voltage measurement connector and configured to receive voltage monitoring electrical signals.

The harness assembly may comprise a plurality of voltage measurement connectors electrically connected at spaced-apart locations along the length of the harness assembly to the electrically conductive track. Each of the plurality of voltage measurement connectors may be configured to measure the voltage of a corresponding cluster of cells (which may be termed a "P-set" or parallel-set to indicate the cells in the cluster are electrically connected in parallel) of the battery module. The electrically conductive track may comprise a plurality of electrically conductive strips located on an electrically insulating support layer. The track may be configured to be located along a side of the battery module across a plurality of electrical cells of the battery module, with the electrically insulating support layer between the plurality of electrically conductive strips and the battery module side.

In a further aspect there is provided a battery module assembly for an electric vehicle, the battery module assembly comprising: a battery module comprising: a plurality of electrical cells; and a module busbar in electrical connection with terminals of the plurality of electrical cells, the battery module having first and second opposite end faces with a side located therebetween; and the harness assembly as described herein, wherein the track is located along the side of the battery module across a plurality of electrical cells of the battery module, and the voltage measurement connector is located over an end of the connection tab of the module busbar of the battery module in resilient gripping engagement therewith.

The voltage measurement connector may be (e.g. laser) welded to the end of the connection tab over which it is located. Therefore, an electrical signal may pass from the electrical cells to the module busbar, to the voltage measurement connector attached to the module busbar connection tab, from the connector via a connecting wire to the track of the harness, and from the harness, for example, to a controller.

In a further aspect there is provided a battery pack comprising a plurality of battery module assemblies (which may be electrically connected together) as described herein.

In a further aspect there is provided a vehicle comprising any the voltage measurement connector, harness assembly, battery module assembly or battery pack described herein.

In a further aspect there is provided a method of forming a voltage measurement connector for a battery module of an electric vehicle; the method comprising shaping a flat conductive sheet to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end, the resilient clip portion configured to fit over an end of a connection tab of a module busbar of a battery module in resilient gripping engagement therewith; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges, the pair of guide tabs configured to be located along opposite edges of a connection tab and, in use, guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion.

In a further aspect there is provided a method of forming an electrical connection to a module busbar of a battery module, the method comprising: providing a voltage measurement connector, the voltage measurement connector comprising a conductive sheet shaped to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges; and sliding the voltage measurement connector onto a connection tab extending from the module busbar to form the electrical connection, by: locating the pair of guide tabs along opposite edges of the connection tab and to guide the voltage measurement connector onto the connection tab; and fitting the resilient clip portion over an end of a connection tab to be in resilient gripping engagement with the connection tab.

The method of forming an electrical connection to a module busbar may further comprise welding the flat central panel of the connector, at an end distal from the clip end, to the connection tab, for example by laser welding.

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 will now be described by way of example only, with reference to the accompanying figures, in which: Figure 1 shows a voltage measurement connector according to examples of

the present disclosure;

Figures 2a-2b show example voltage measurement connectors attached to a connection tab according to examples of the present disclosure; Figure 3 shows a harness assembly according to examples of the present

disclosure;

Figure 4 shows an example battery module assembly according to examples of the present disclosure; Figure 5 show an example method of forming a voltage measurement connector according to examples of the present disclosure; Figure 6 shows an example method of forming an electrical connection to a module busbar of a battery module according to examples of the present disclosure; and Figure 7 shows an example vehicle according to examples of the present disclosure.

DETAILED DESCRIPTION

An electric vehicle may be, for example, a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). A battery module may be considered to be any battery module of a vehicle, for example, a module of a battery (or a battery per se) which may be used to, for example, start the engine. A traction battery module may be considered to be a module of a traction battery (or a traction battery per se) which is used to drive the vehicle (i.e. power the powertrain to propel the vehicle).

A battery, or battery module (e.g. a traction battery module) for an electric vehicle may comprise an array of electrical cells (e.g. (rechargeable) battery cells, and/or capacitors e.g. supercapacitors, configured to store electrical charge) which may be located in a housing/casing. Electrical measurements may be taken from the cells via connection of the cells to a busbar, and from there, to a connection outside the battery (or battery module) for measurement readout. For example, it is important to be able to reliably monitor the voltage, temperature, or other parameters of the battery to check its operation, for example for safety and battery health monitoring.

Improving battery technology and battery manufacture, for example for use in electric vehicles, is important in view of recent interest in providing cleaner energy solutions. An area for improvement is taking electrical measurements from the battery cells. Examples disclosed here may address problems in the art relating to making electrical connections to cells.

For example, it may be advantageous to be able to easily form an electrical connection to a cell or group of cells during battery module manufacture. It is preferable for such a connection to be robust and not become easily disconnected, for example due to a vehicle containing the battery being used, which causes vibrations and shocks/bumps to the battery as the vehicle is driven.

Figure 1 shows an example of a voltage measurement connector 100. By "connector" it is meant that the connector 100 is configured to itself connect to another object (e.g. a busbar connection tab). The connector may also be called a clip, for example, in the sense that it is configured to "clip" onto another object to connect itself to the object. The connector 100 comprises a flexible, or spring-loaded; portion which is configured to hold the connector 100 onto another object and form a connection to the other object. The connector 100 is suitable or use in a battery module of an electric vehicle.

The connector 100 comprises a conductive sheet which is shaped (i.e. shaped in the sense of forming a particular 2D shape, for example by cutting or stamping the 2D shape from a sheet of conductive material) into a cross-shaped net which is then bent in places (i.e. shaped in the sense of portions of the net being bent out of the 2D plane, which as shown is the y-z plane) to provide various features. The connector 100 comprises a flat central panel 102 providing/defining a pair of guide edges 104a, 104b along opposite sides of the central panel 102 and a clip end 106 between the pair of guide edges 104a, 104b.

The connector 100 comprises a resilient clip portion 108 located at the clip end 106. The resilient clip portion 108 is configured to fit over an end of a connection tab of a module busbar of a battery module, in resilient gripping engagement therewith. This is illustrated in more detail in Figures 2a-b. By "resilient gripping engagement" it is meant that the clip portion 108 acts as a self-clamping clip. The connector 100 is not necessarily to be used in a way which causes it to be fitted, removed, and re-fitted onto a connection tab several times such that the material from which it is made should be sufficiently resilient for such repeated deformation through fitting and re-fitting. It may be used in a way whereby it is fitted and perhaps fitted once or twice further, for example, if it is unintentionally fitted to an incorrect connection tab. The resilient nature of the material from which the connector 100 is made should be sufficient to allow for the connector to be clipped onto a connection tab in a gripping engagement to allow for the connector 100 to "self-clamp" onto the connection tab and allow for subsequent further mechanical connection to the connection tab by welding the connector 100 onto the connection tab. It is this welded connection which, in the long term, provides a strong mechanical connection, as well as a good electrical connection, between the connector and the connection tab. The "resilient gripping engagement" of the connector 100 onto a connection tab facilitates easy welding of the connector 100 to the connection tab, e.g. by laser welding, without requiring particular alignment step or external clamping means to allow for welding in the desired arrangement.

The smallest distance 114 between the folded-over clip portion 112 and the flat central panel 102 (indicated in figure 1 as the portion towards the bottom/free end of the folded-over clip portion 112) may be smaller than the thickness of the connection tab which the connector is intended to be attached to. The material from which the connector 100 is made is suitably resilient ("springy") such that, when the connector 100 is attached to a connection tab that is thicker than the smallest distance 114, an elastic deformation of the clip portion 108 occurs,at least predominantly at the hinge portion 116 of the clip portion 108, to allow the clip portion 108 to slot onto the connection tab and grip it at the narrowest portion 114. Deformation of the clip portion 112 may be at least partially elastic, and in some examples, also partially plastic. Importantly, the deformation is such that the clip portion 112 holds the connector 100 onto a connection tab securely, e.g. to allow the connector 100 to be welded onto the connection tab without requiring external clamping means.

The connector 100 comprises a pair of guide tabs 110a, 110b. Each of the pair of guide tabs 110a, 110b is located at a respective guide edge 104a, 104b of the pair of guide edges. The pair of guide tabs 110a, 110b is configured to be located along opposite edges of the connection tab when the connector 100 is attached to a connection tab. In use, the pair of guide tabs 110a, 110b is configured to guide the voltage measurement connector 100 into resilient gripping engagement with the connection tab via the resilient clip portion 108.

In this example, the resilient clip portion 108, and the connector 100 overall, is configured to fit over a flat elongate connection tab. This is illustrated in more detail in Figures 2a-2b. Also as shown, the flat central panel 102 may comprise an inner surface 118 and an outer surface 120, and the folded-over clip portion 112 and the pair of guide tabs 110a, 110b are located on the same side of the flat central panel 102 towards the inner surface 118 (as shown, bent out of the y-z plane in the +x direction).

In this example, the pair of guide tabs 110a, 110b are parallel, and each have a tab plane (the x-z plane in this example) perpendicular to a plane of the flat central panel 102 (the y-z plane in this example). By having parallel alignment with each other (and with the sides of a connection tab to which the connector 100 is to attach to), the guide tabs 110a, 110b act to mitigate against axial rotation of the connector 100 in the plane of the connection tab (and the central panel 102, i.e. the y-z plane as shown in Figure 1) when the connector 100 is being pushed onto on the connection tab (along the z-axis as shown).

In other examples, the guide tabs 110a, 110b need not necessarily be parallel -for example they may form a tapered or "V" shape being wider at the end distal from the clip end 106 and narrower towards the clip end 106. Such an arrangement may allow for the connector to be easily slid onto a connection tab, because the initial part of the connector 100 to slide onto the connection tab distal from the clip end 106 allows for a wide span in which the connection tab can lie. As the connector 100 is slid onto the connection tab, the connector 100 "self-aligns" because the guide tabs 110a, 110b allow for decreasing movement of the connection tab On the y-x plane as shown) in the space defined by the flat central portion 102 and guide tabs 110a, 110b. Such an arrangement may also allow for a connection tab having non-parallel edges (i.e. a "tapered" connection tab) to be clipped onto.

In this example, each guide tab 110a, 110b extends part of the way along the respective guide edge 104a, 104b but not all the way along. In other examples each guide tab 110a, 110b may extend all the way along the respective guide edge 104a, 104b although this would require more material from which to manufacture the connector 100. In other examples each guide tab 110a, 110b may extend a shorter distance along the respective guide edge 104a, 104b than shown, although it is important to ensure the guide tabs 110a, 110b are long enough to allow the connector 100 to be slid onto a connection tab and provide the effect of preventing (or at least mitigating against) rotational movement in the plane of the flat central panel (the y-z plane as shown) as the connector 100 is slid into place.

In the example of Figure 1, the guide tabs 110a, 110b are planar panels extending in the x-z plane. In some examples, the guide tabs 110a, 110b may also have overlap portions which fold over from the free ends of the guide tabs 110a, 110b, towards each other, and act to "grab onto" a connection tab, and further act to align the connector 100 with the connection tab whilst the connector 100 is slotted onto the connection tab along the z-axis as shown. This may prevent (or at least mitigate against) undesirable movement of the connector tilting away from the connecting tab before the resilient clip portion engages with the connection tab (such that the inner portion 118 and connector tab are no longer in good contact).

The resilient clip portion 108 in this example comprises an end portion (the hinge portion 116 and folded-over clip portion 112) which is configured to fit over the end of the connection tab. The end portion, specifically the folded-over clip portion 112 has an end lip 122 which is angled away from the flat central panel 102 (as shown, it is angled to point towards the x direction) whereas the flat central plane lies in the y-z plane). The end lip 122 acts to facilitate sliding the voltage measurement connector 100 onto a connection tab and engaging the resilient clip portion 108 with the connection tab, because the flat central panel 102 and lip portion 122 form a "V", or angled "mouth" which the connection tab can be located in before pushing the connector 100 onto the connection tab more fully.

The resilient clip portion 108 helps to ensure that the connector 100 may be fitted onto a tab in a particularly easy manner without the need for high levels of force. A manufacturing operator who fits the connector 100 is able to push down on the hinged portion 116 which provides a suitable smooth and rounded surface. The resilient clip portion 108 does not need to provide a high fastening force because the electrical connection is reliably made via a subsequent welding process. So this design of connector is ideally suited to mass production of battery packs.

The voltage measurement connectors 100 discussed herein comprise an electrically conductive material. For example, the conductive sheet of the connector 100 may comprise copper or a copper alloy such as copper alloyed with zinc and/or nickel. The conductive sheet may also be made of a coated copper or copper alloy e.g. nickel coated copper. Copper provides good electrical conductivity. Nickel helps to reduce any corrosion to the connector. The conductive sheet may have a thickness of between 150 microns and 500 microns; such as between 200 microns and 400 microns; preferably about 300 microns. The connector may have a width dimension between the pair of guide edges of between 3mm and 10mm; preferably between about 6mm and 7mm. The connector may have a length dimension between an edge proximal to the clip end and an opposite edge opposite to the clip end of between 8mm and 20mm, such as between 10mm and 13mm, e.g. 11.5mm.

Figures 2a-2b illustrate a voltage measurement connector 100 with respect to a connection tab 200 of a busbar when the connector 100 is clipped onto the connection tab 200 (i.e. the connector 100 is installed in the battery module; it is in position on a connection tab 200 for use as part of the battery module). The connector tab 200 is illustrated in dashed lines to illustrate where the connector 100 is in relation to a connection tab 200 once installed thereon. Figure 2a shows a schematic view of the outer (rear) surface of the connector 100, and Figure 2b shows a schematic view of the inner (front) surface of the connector 100.

In these examples, the voltage measurement connector 100 is configured to be slid onto a connection tab 200 and then laser welded 202 onto the connection tab 200. Laser welding 202 the connector 100 to the connection tab strengthens the connection between the two elements 100, 200 for improved robustness over the life cycle of the battery module in use. Laser welding 202 the connector 100 to the connection tab also helps to ensure an excellent electrical connection such that there is negligible additional contact resistance as is typically associated with standard (unwelded) connectors. Any additional resistance would impact the accuracy of the voltage measurement. Laser welding 202 the connector 100 to the connection tab helps to ensure that there is negligible variability in the contact resistance, so voltages are measured reliably. This is very advantageous for managing the health of the battery pack, because it allows for all cells to have their voltages very precisely monitored.

The laser weld 202 may comprise, for example, a circular shaped weld overall. The circular weld itself may be laser welded as a looped path formed by the welding laser path oscillating about a centreline around the overall circular path. The clip portion at the clip end 206 acts to self-clamp the connector 100 onto the connecting tab 200 when in position on the connecting tab 200 by gripping onto the connecting tab 200.

This facilitates laser welding (or other welding or fixing) of the connector 100 to the connecting tab 200 by holding the two elements 100, 200 in tight contact with each other without the need for an additional external clamping means being used to hold them together -this makes the manufacturing process simpler by not requiring an external clamp, and facilitates laser welding as there is no external clamp obscuring the line of sight to the connector 100 required for laser welding to be performed.

In some examples, as shown, the inner surface 118 of the flat central panel 102 of the connector 100 is configured to, in use, lie coplanar with and adjacent to a flat face 204 of the connection tab 200 to which the connector 100 is connected. Having two flat faces 118, 204 in contact with each other facilitates laser welding to connect the two elements, and produce a strong welded join. The "self-clamping" action of the resilient clip portion 106 also acts to hold the flat faces 118, 204 of the connector and connection tab together, further helping the formation of a good quality strong laser weld. In these examples, the flat central panel 102 of the connector 100, at an end 208 distal from the clip end 206, is configured to be laser welded 202 onto the connection tab 200. This provides spatially separated anchor points for the connector 100 on the connection tab 200, i.e. the laser weld in the distal region 208 and the resilient gripping of the clip portion at the clip end 206 gripping the connection tab 200, to provide a robust connection.

Figure 2a shows that the voltage measurement connector 100 comprises a connecting wire 210 attached to the conductive sheet On this example, on the outer surface of the flat central panel 102, spatially separated from the laser weld 202). The connecting wire 210 is configured to provide voltage monitoring electrical signals from the attached connection tab 200 to a controller -this is discussed more in relation to Figure 3. The connecting wire 210 is attached to the flat central panel 102 of the conductive sheet at an end 206 proximal to the clip portion (i.e. the clip end 206). The connector 100 may be attached to the connecting wire 210 by a soldered connection 212, for example. In some examples, the soldered connection 212 may be made to a region of the conductive sheet that is not the flat central panel 102. For example, the soldered connection 212 may be made to an angled portion at the end of the connector 100 which is distal to the clip end, and which is contiguous with the flat central panel 102 but not coplanar with the flat central panel 102.

Figure 3 illustrates, to scale, an example harness assembly 300 for a battery module of an electric vehicle. The harness assembly 300 comprises at least one voltage measurement connector 100 as described herein. The harness assembly 300 also comprises an electrically conductive track 302 which is electrically connected to the voltage measurement connector(s) 100, for example by respective connecting wires. The track 302 is configured to receive voltage monitoring electrical signals from the connectors 100. In this example, several connectors 100 are shown distributed along the length of the track; in other words, the harness assembly 300 comprises a plurality of voltage measurement connectors 100 electrically connected at spaced-apart locations along the length of the harness assembly 300, to the electrically conductive track 302. Each of the plurality of voltage measurement connectors 100 is configured to measure the voltage of a corresponding cluster of cells (a "P-set") of the battery module to which the harness is attached. This is shown in more detail in Figure 4.

Figure 4 illustrated an example battery module assembly 400 to scale. The battery module assembly 400 is suitable for used in an electric vehicle, for example as a (part of a) traction battery for powering the powertrain of the vehicle. The battery module assembly 400 comprises a battery module 410. The battery module 410 itself comprises a plurality of electrical cells 402; and a module busbar in electrical connection with terminals of the plurality of electrical cells 402. The battery module 410 has first and second opposite end faces 404, 406 with a side 408 located therebetween. Also shown is a harness assembly 300 as discussed in relation to Figure 3. The track of the harness assembly 300 is located along the side 408 of the battery module 410 across a plurality of electrical cells 402 of the battery module 410. The voltage measurement connector(s) 100 are each located over an end of a corresponding connection tab of module busbar of the battery module 400 in resilient gripping engagement therewith.

The electrically conductive track of the harness 300 comprises a plurality of electrically conductive strips located on an electrically insulating support layer. The track is configured to be located along the side 408 of the battery module 400, across a plurality of electrical cells 402 of the battery module 410, with the electrically insulating support layer between the plurality of electrically conductive strips and the battery module side 408. The voltage measurement connectors 100 may be laser welded to the respective end of the connection tab over which each is located. Therefore, an electrical signal may pass from the electrical cells 402 to the module busbar, to the voltage measurement connector 100 attached to the module busbar connection tab, via a connecting wire to the track of the harness 300, and from the harness 300, for example, to a controller. The controller may be located at an end 404, 406 of the battery module assembly 400 and may receive signals from the battery module assembly, such as voltage readings of cells in battery modules 410 of the battery module assembly 400 as sensed at the voltage measurement connector 100 attached to the module busbar of a battery module. Other signals may also be sensed and transmitted by the harness for output to the controller, such as a temperature reading sensed by a thermistor connected to the harness 300. A battery pack may be provided, comprising a plurality of electrically connected battery module assemblies 400.

Figure 5 shows a method 500 of forming a voltage measurement connector for a battery module of an electric vehicle. The method comprises shaping a flat conductive sheet 502 to provide: a flat central panel 504 providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion 506 located at the clip end, the resilient clip portion configured to fit over an end of a connection tab of a module busbar of a battery module in resilient gripping engagement therewith; and a pair of guide tabs 508, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges, the pair of guide tabs configured to be located along opposite edges of a connection tab and, in use, guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion.

Figure 6 shows a method 600 of forming an electrical connection to a module busbar of a battery module. The method 600 comprises: providing a voltage measurement connector 602, the voltage measurement connector comprising a conductive sheet shaped to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges. The method 600 also comprises sliding the voltage measurement connector onto a connection tab extending from the module busbar to form the electrical connection 604. This is achieved by: locating the pair of guide tabs along opposite edges of the connection tab and to guide the voltage measurement connector onto the connection tab 606; and fitting the resilient clip portion over an end of a connection tab to be in resilient gripping engagement with the connection tab 608. The method 600 may also comprise welding the flat central panel of the clip, at an end distal from the clip end, to the connection tab, in some examples.

Figure 7 illustrates a vehicle 700, comprising any voltage measurement connector, harness assembly, the battery module assembly, or battery pack disclosed herein.

It will be appreciated that certain examples disclosed herein can be realised in the form of hardware, software or a combination of hardware and software; for example software to control a control system to perform at least a part of a method as discussed above e.g. in an automated or semi-automated process. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. Such software may comprise computer readable code stored on a non-transitory computer-readable storage medium. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs that, when executed, implement embodiments disclosed herein. Accordingly, embodiments provide a program comprising code for implementing a system or method as claimed in any preceding claim and a machine readable storage storing such a program. Still further, embodiments disclosed herein may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.

Figure 8 shows an example vehicle 800 comprising any end cap 100 disclosed herein, any battery module 600 disclosed herein, or any battery pack disclosed herein.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

Claims

CLAIMS1. A voltage measurement connector for a battery module of an electric vehicle, the voltage measurement connector comprising a conductive sheet shaped to 5 provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end, the resilient clip portion configured to fit over an end of a connection tab of a module busbar of a battery module in resilient gripping engagement therewith; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges, the pair of guide tabs configured to be located along opposite edges of the connection tab and, in use, guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion.
2. The voltage measurement connector of claim 1, wherein the pair of guide tabs are parallel and each have a tab plane perpendicular to a plane of the flat central panel.
3. The voltage measurement connector of any preceding claim, wherein the resilient clip portion comprises an end portion configured to fit over the end of the connection tab, the end portion having an end lip angled away from the flat central panel to facilitate sliding the voltage measurement connector onto the connection tab.
4. The voltage measurement connector of any preceding claim, configured to be slid onto the connection tab and then laser welded onto the connection tab.
5. The voltage measurement connector of any preceding claim, wherein an inner surface of the flat central panel of the connector is configured to, in use, lie coplanar with and adjacent to a flat face of the connection tab to which the connector is connected.
6. The voltage measurement connector of claim 4 or claim 5, wherein the flat central panel of the connector, at an end distal from the clip end, is configured to be laser welded onto the connection tab.
7. The voltage measurement connector of any preceding claim, comprising a connecting wire attached to the conductive sheet, the connecting wire configured to provide voltage monitoring electrical signals from the attached connection tab to a controller.
8. The voltage measurement connector of claim 7, wherein the connecting wire is attached to the flat central panel of the conductive sheet at an end proximal to the clip end.
9. The voltage measurement connector of claim 7 or claim 8, wherein the connector is configured to be attached to the connecting wire by a soldered connection.
10. The voltage measurement connector of any preceding claim, wherein the conductive sheet comprises nickel coated copper.
11. The voltage measurement connector of any preceding claim, wherein the conductive sheet has a thickness of between 150 microns and 500 microns; preferably between 200 microns and 400 microns; more preferably about 300 microns.
12. The voltage measurement connector of any preceding claim, wherein one or more of: the connector has a width dimension between the pair of guide edges of between 3mm and 10mm; preferably between 6mm and 7mm; and the connector has a length dimension between an edge proximal to the clip end and an opposite edge opposite to the clip end of between 8mm and 20mm; preferably between 10mm and 13mm; more preferably about 11.5mm.
13. A harness assembly for a battery module of an electric vehicle, comprising: at least one voltage measurement connector of any preceding claim; and an electrically conductive track electrically connected to the voltage measurement connector and configured to receive voltage monitoring electrical 35 signals.
14. The harness assembly of claim 13, comprising a plurality of voltage measurement connectors electrically connected at spaced-apart locations along the length of the harness assembly to the electrically conductive track.
15. The harness assembly of claim 14, wherein each of the plurality of voltage measurement connectors is configured to measure the voltage of a corresponding cluster of cells of the battery module.
16. The harness assembly of any of claims 13 to 15, wherein the electrically conductive track comprises a plurality of electrically conductive strips located on an electrically insulating support layer, wherein the track is configured to be located along a side of the battery module across a plurality of electrical cells of the battery module, with the electrically insulating support layer between the plurality of electrically conductive strips and the battery module side.
17. A battery module assembly for an electric vehicle, the battery module assembly comprising: a battery module comprising: a plurality of electrical cells; and a module busbar in electrical connection with terminals of the plurality of electrical cells, the battery module having first and second opposite end faces with a side located therebetween; and the harness assembly of any of claims 13 or 16, wherein: the track is located along the side of the battery module across a plurality of electrical cells of the battery module, and the voltage measurement connector is located over an end of the connection tab of the module busbar of the battery module in resilient gripping engagement therewith.
18. The battery module assembly of claim 17, wherein the voltage measurement connector is laser welded to the end of the connection tab over which it is located.
19. A battery pack comprising at least one battery module assembly according to claim 17 or claim 18.
20. A vehicle comprising: the voltage measurement connector of any of claims 1 to 12; the harness assembly of any of claims 13 to 16; the battery module assembly of claim 1701 claim 18; or the battery pack of claim 19.
21. A method of forming a voltage measurement connector for a battery module of an electric vehicle; the method comprising shaping a flat conductive sheet to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end, the resilient clip portion configured to fit over an end of a connection tab of a module busbar of a battery module in resilient gripping engagement therewith; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges, the pair of guide tabs configured to be located along opposite edges of a connection tab and, in use, guide the voltage measurement connector into resilient gripping engagement with the connection tab via the resilient clip portion.
22. A method of forming an electrical connection to a module busbar of a battery module, the method comprising: providing a voltage measurement connector, the voltage measurement connector comprising a conductive sheet shaped to provide: a flat central panel providing a pair of guide edges along opposite sides of the central panel and a clip end between the pair of guide edges; a resilient clip portion located at the clip end; and a pair of guide tabs, each of the pair of guide tabs located at a respective guide edge of the pair of guide edges; and sliding the voltage measurement connector onto a connection tab extending from the module busbar to form the electrical connection, by: locating the pair of guide tabs along opposite edges of the connection tab and to guide the voltage measurement connector onto the connection tab; and fitting the resilient clip portion over an end of a connection tab to be in resilient gripping engagement with the connection tab.
23. The method of forming an electrical connection to a module busbar of claim 22, further comprising welding the flat central panel of the connector, at an end distal from the clip end, to the connection tab.