Electrical connector

Abstract

An assembly comprises a PCB 180 having at least two through-holes 186 extending through the PCB between a first side 182 and a second side 184, the first side of the PCB including at least two conductive traces 81 (Figure 1), at least partially surrounding the through-holes; a battery cell 102 comprising a body, a positive terminal and a negative terminal 104, both terminals being at a first end of the body; and a cap 162 electrically connected to each of the positive and negative terminals, each cap including a contact surface 140, and each cap being connected to the terminal by an insertion element 150 (e.g. threaded screw); each insertion element extends through a through-hole of the PCB such that the body of the battery cell is disposed on the second side of the PCB and the contact surface of each cap is in electrical contact with one of the conductive traces. A connector 10 (Figure 2) is separately claimed comprising female connector 12 and male connector 14.

Description

FIELD OF THE INVENTION This invention relates to connectors for forming a mechanical and electrical connection between a component and a printed circuit board (PCB). This invention relates to connectors for forming a solderless mechanical and electrical connection between a component and a printed circuit board (PCB). This invention relates in particular to connectors for connecting the terminals of a battery cell to a PCB to form an electrical connection between the battery and the PCB, and to assemblies including such connectors. BACKGROUND TO THE INVENTION A battery for an electric vehicle is commonly referred to as a electric vehicle battery pack. The pack is composed of a number of battery modules, and each module is composed of a number of battery cells. The battery cells are mounted in a frame to protect the cells from external shocks and heat to form a battery module. The final battery pack comprises a number of battery modules, together with control and protection systems. As an example, a battery pack for a vehicle may include 8 modules, with each module including 12 cells. In general electric car batteries that include lithium-ion cells last between 10 and 20 years, before degradation of the battery cells is such that the battery needs to be replaced. The cost to replace such a battery pack may be around £15,000. Even before the battery pack needs to be replaced, a user of an electric car may notice a deterioration in the battery performance. In particular, the maximum potential of the battery may decrease so that the maximum milage range of the vehicle also decreases. In general the cells in the battery pack deteriorate at different rates. Accordingly, it is advantageous if a user can simply replace individual battery cells or modules when required, rather than needing to replace the whole battery pack in one go. To achieve this it is known to monitor the state or condition of each of the cells in the battery pack. This allows a user to identify which individual cells need replacing. However, due to the complex connection within each battery module and battery pack, it is currently difficult or impossible to replace cells individually. It is therefore an aim of the present invention to provide a connector suitable for connecting a battery cell to a PCB to permit easy replacement of the battery cell. SUMMARY OF THE INVENTION A first aspect of the present invention provides an assembly comprising: a PCB having at least two through-holes extending through the PCB between a first side and an opposite second side, a first surface on the first side of the PCB including at least two conductive traces, a part of each of the conductive traces surrounding a respective through-hole; a battery cell comprising a body, a positive terminal and a negative terminal, both terminals being at a first end of the body; and a cap electrically connected to each of the positive and negative terminals, each cap including a contact surface, and each cap being connected to the respective terminal by an insertion element, wherein each insertion element extends through a respective through-hole of the PCB such that the body of the battery cell is disposed on the second side of the PCB and the contact surface of each cap is in electrical contact with one of the conductive traces. In some embodiments each insertion element is permanently attached to or integral with the respective terminal of the battery cell. In other embodiments the battery cell comprises a positive terminal pin integral with the positive terminal and extending from the first end of the body and a negative terminal pin integral with the negative terminal and extending from the first end of the body, and wherein each insertion element is engaged with and detachable from the respective terminal pin. The cap and insertion element may be parts of a male connector element, the male connector element further comprising first retaining features. The assembly preferably further comprises two female connector elements each having second retaining features. Preferably the first and second retaining features of respective pairs of male and female connector elements are engaged with each other to maintain an electrical connection between the positive and negative terminals of the battery cell and the contact surfaces of the caps. In some embodiments each of the positive terminal pin and negative terminal pin provide a respective female connector element for receiving the corresponding male connector element. The female connector elements may be in the form of a collar for receiving a part of a terminal pin and a part of a male connector element. Each male connector element may include a pair of gripping jaws and each female connector element may include a bearing surface. Preferably, when the male and female connector elements are engaged with each other, the bearing surface applies a force to the gripping jaws to cause the jaws to grip a part of a respective terminal pin of the battery cell. In some embodiments the first and second retaining features are complementary screw threads. In other embodiments the first and second retaining features may be complementary interlocking ribs. In some embodiments a conductive collar is mounted in each of the through-holes, and a part of a flange of each conductive collar is in electrical contact with a part of the respective conductive trace surrounding the through-hole. In these embodiments the contact surface of each cap is preferably in contact with the flange of a respective collar. Preferably the battery cell is a carbon battery cell. The assembly may comprise a plurality of battery cells, the battery cells being electrically connected to the conductive traces either in parallel or in series. In some embodiments the assembly may further comprise: a base plate including a plurality of recesses, each recess for receiving a second end of the body of one of the battery cells; an insulating tube surrounding the body of each battery cell; and a cover extending over the first side of the PCB and connected to the base plate. A second aspect of the invention provides a battery module for an electric vehicle comprising an assembly according to the first aspect of the invention. A third aspect of the invention provides a connector for electrically connecting a terminal of a battery cell on a second side of a PCB to a conductive trace on a first side of a PCB, the connector comprising: a male connector element having an insertion portion including first retaining features and a cap extending from the insertion portion including a flange having a contact surface; and a female connector element having a receiving portion including second retaining features, the second retaining features being engageable with the first retaining features to maintain a connection between the male connector element and the female connector element, wherein the insertion portion is sized to extend through a through-hole of a PCB so that, in use, the contact surface is held in contact with said conductive trace, and the female connector element is connectable to or integral with said battery cell terminal, and wherein at least the male connector element is electrically conductive. Preferred and / or optional features of each aspect and embodiment described above may also be used, alone or in appropriate combination, in the other aspects and embodiments also. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described by way of example only and with reference to the accompanying drawings, in which like reference signs are used for like features, and in which: Figure 1 is a perspective view showing a battery cell connected to a PCB, in which each of the terminals of the battery cell are electrically and mechanically connected to the PCB by a connector according to a first preferred embodiment of the invention; Figure 2 is a cross-sectional drawing of one of the connectors of Figure 1 showing the connector attached to a PCB and a battery terminal; Figure 3 shows the connector of Figure, with a first part of the connector on a first side of a PCB and a second part of the connector on a second side of the PCB; Figure 4 is a perspective view of the first part of the connector of Figure 3; Figure 5 is a perspective view of the second part of the connector of Figure 3; Figure 6 shows components of a connector according to a second embodiment of the invention for forming an electrical connection between a battery and traces of a PCB; Figure 7 shows components of a connector according to a third embodiment of the invention for forming an electrical connection between a battery and traces of a PCB; Figure 8 shows components of a connector according to a fourth embodiment of the invention for forming an electrical connection between a battery and traces of a PCB; Figure 9 shows components of a connector according to a fifth embodiment of the invention for forming an electrical connection between a battery and traces of a PCB; and Figure 10 illustrates a battery module comprising a plurality of battery cells electrically connected to traces of a PCB. DESCRIPTION OF THE PREFERRED EMBODIMENTS A battery cell generally includes a body including a casing that defines an internal volume containing an electrolyte. The cell further includes a positive electrode and a negative electrode. The positive electrode is connected to a positive terminal of the battery cell, and the negative electrode is connected to a negative terminal of the battery cell. The positive and negative terminals are provided external to the casing to permit an electrical connection to be formed between these terminals and an electrical circuit to provide electrical power to the circuit. The positive and negative terminals are electrically conductive, but may take any of a number of different physical forms. In some battery cells the terminals comprise metals caps or covers of the cell casing. In other battery cells the terminals may be in the form of tabs or pins protruding from the casing. The present invention provides a connector for forming a mechanical and electrical connection between terminals of a battery cell and an electrical circuit that is preferably provided on the surface of a printed circuit board (PCB). A connector of the invention is designed to engage with and connect to one of the terminals of a battery cell. In some embodiments the connector is configured to grip or clamp a protruding terminal in the form of a terminal pin or tab. References in the following description to a battery terminal being in the form of a pin should therefore be considered to also encompass a battery terminal in the form of a tab or other generally elongate structure protruding or extending from a body of a battery cell. A connector according to the invention provides a solderless electrical connection between a battery and a printed circuit, allowing the battery cell of to bquickly and easily disconnected from the circuit for replacement. The connector of the invention is particularly suited for use with batteries having both positive and negative terminals protruding from the same end of the cell body. It will be understood that the positive terminal and negative terminal, therefore, extend in substantially the same direction from the body of the cell. The positive terminal and negative terminal may extend generally parallel to each other. The body of the battery cell may be generally cylindrical. The connector is preferably arranged to electrically connect a battery cell on a second side of a PCB to a conductive trace on a first side of the PCB. Referring now to Figures 1 to 5, an embodiment of a connector 10 according to the present invention comprises a first, female connector element 12 and a second, male connector element 14. The male connector element 14 is at least partially insertable into the female connector element 12 to engage the male connector element 14 with the female connector element 12. In this embodiment the first, female connector element 12 comprises a generally cylindrical body 16 having a first end surface 18 and an opposite second end surface 20. A depth of the female connector element 12 is defined as a distance between the first and second end surfaces 18, 20. The first and second end surfaces 18, 20 are preferably planar and parallel to each other. A hole or bore 22 extends through the body 16 between the first and second end surfaces 18, 20. An axis of the bore 22 preferably extends substantially perpendicular to the planes of the first and second end surfaces 18, 20. At the first end surface 18, the bore 22 defines a first aperture 24 and at the second end surface 20, the bore 22 defines a second aperture 26. In this embodiment the first aperture 24 has a generally circular shape and the second aperture 26 has a generally circular shape. A diameter of the second aperture 26 is smaller than a diameter of the first aperture 24. In other embodiments the second aperture may have an oval shape or be in the form of a slot. A receiving portion 30 of the bore 22 extends from the first aperture 24 or first end surface 18 in a direction towards the second end surface 20. Preferably the receiving portion does not extend fully through the depth of the female connector element 12. In this embodiment a first, engagement region 32 of the receiving portion 30 is defined adjacent the first end surface 18. An internal surface of the bore 22 in the engagement region 32 has retaining features in the form of a female screw thread 34 for retaining engagement with the male connector element 14 as described below. A second, clamping region 36 of the receiving portion 30 is disposed between the engagement region 32 and the second aperture 26. In this embodiment the internal surface of the bore 22 in the clamping region 36 provides a bearing surface 38. The bearing surface 38 has a truncated conical shape, and a diameter of the bore 22 in the clamping region 36 decreases from a larger diameter of the engagement region 32 to the smaller diameter of the second aperture 26. It will be appreciated that, while the body of the female connector element of this embodiment is generally cylindrical, the body may have any suitable shape. Importantly, the shape of the receiving portion of the bore is complementary to that of the insertion portion of the male connector element so that the male connector element and female connector element are engageable, as described above. The shape of the second aperture may be any suitable shape for receiving a terminal of a battery cell therethrough. Preferably the shape and size of the second aperture is such that there is minimal freedom of movement of the terminal in the second aperture in directions transverse to the axis of the bore. The second, male connector element 14 comprises a contact portion 40 and an insertion portion or insertion element 42. The insertion portion 42 extends from a first end 44 to a second end 46, and an axis of the insertion portion 42 extends between the first end 44 and the second end 46. In this embodiment the insertion portion 42 comprises an engagement region 48 proximate or adjacent the first end 44. The engagement region 48 is generally cylindrical and an outer surface of the engagement region 48 includes retaining features in the form of a male screw thread 50. The male screw thread 50 is configured to engage with the female screw thread 34 to retain the male connector element 14 in engagement with the female connector element 12. A clamping region 52 of the insertion portion 42 is disposed between the engagement region 48 and the second end 46 of the insertion portion 42. In this embodiment an outer surface of the clamping region 52 provides a bearing surface 54. The bearing surface 54 has a conical shape, and a diameter of the clamping region 52 decreases from a larger diameter adjacent the engagement region 48 to the second end 46 of the insertion portion 42. In this embodiment the second end 46 of the insertion portion 42 forms a tip of the insertion portion 42. A slot 56 extends through the clamping region 52. A plane of the slot 56 is parallel to the axis of the insertion portion 42. Preferably the axis of the insertion portion 42 lies in the plane of the slot 56. The slot 56 therefore divides the clamping region 52 into two half-conical jaws 58. Each of the jaws 58 includes a gripping surface 60. The gripping surfaces 60 of the jaws 58 oppose each other across the width of the slot 56 and define sides of the slot 56. The contact portion 40 extends from the first end 44 of the insertion portion 42. In this embodiment the contact portion 40 comprises a cap 62. A diameter of the cap 62 is greater than the diameter of the engagement region 48 such that the contact portion 40 includes a flange 64 that extends radially outwardly from the insertion portion 42. The cap 62 includes a contact surface 66 that, in use, contacts a trace on a surface of a PCB to form an electrical connection. In this embodiment the contact surface is an annular surface of the flange 64 that faces in a direction towards the insertion portion 42. In this embodiment a top surface 68 of the cap 62, that faces in a direction away from the insertion portion 42, provides a driving feature in the form of a slot 70 for receiving a screwdriver. The connector 10 may be used to mechanically and electrically connect a battery cell 2, having both positive and negative terminals 4 protruding from a first end of a cell body 6, to a PCB 80 including a conductive trace 81 on a first surface 82 of the PCB 80. As shown in Figures 2 and 3, the PCB 80 includes a through-hole 86 (extending through the PCB 80 between the first surface 82 and an opposite second surface 84) that is surrounded by the conductive trace on the first surface 82. A first connector 10 is used to connect the positive terminal 4 of the battery cell 2 to the PCB 80, and a second connector 10 is used to connect the negative terminal 4 of the battery cell 2 to the PCB 80. To achieve this, the female connector element 12 is disposed on a second side of the PCB 80 with the first end surface 18 in contact with the second surface 84 of the PCB 80. A terminal pin 4 of the battery cell 2 is inserted though the second aperture 26 and into the bore 22 of the female connector element 12. The male connector element 14 is then inserted through the through-hole 86 of the PCB 80 so that the cap 62 is disposed on a first side of the PCB 80. The insertion portion 42 of the male connector element 14 extends through the though-hole 86 and into the bore 22 of the female connector element 12. The terminal pin 4 locates in the slot 56 between the jaws 58. To engage the engagement region 48 of the male connector element 14 with the engagement region 32 of the female connector element 12, in this embodiment the male connector element 14 is rotated about its axis to engage the complementary screw threads 34, 50. This rotation may be driven by engaging a screwdriver in the slot 70 in the cap 62. As the screw threads 34, 50 are further engaged, the clamping region 52 of the male connector element 14 is pushed into the clamping region 36 of the female connector element 12. The conical bearing surface 38 of the clamping region 36 of the female connector element 12 applies a force to the jaws 58 of the male connector element 14 to push the jaws 58 in directions towards each other. This causes a width of the slot 56 to decrease and the gripping surfaces 60 to apply an increasing gripping force to the terminal pin 4 disposed in the slot 56. When the engagement region 48 of the male connector element 14 is fully engaged with the engagement region 32 of the female connector element 12 the PCB 80 is clamped between the first end surface 18 of the female connector element 12 and the contact surface 66 of the male connector element 14. As the conductive trace 81 of the PCB 80 surrounds the through-hole 86, the contact surface 66 is brought into contact with the conductive trace 81. An electrical connection is therefore formed between the terminal pin and the conductive trace by the connector 10. It will be understood that to form the electrical connection at least the male connector element 14 must be made from a suitable electrically conductive material. The profile or height of the cap 62, i.e. a distance between the top surface 68 and the contact surface 66, is preferably less than the maximum height of other component affixed to the first surface 82 of the PCB 80. Referring now to Figure 6, a second embodiment of a connector 110 comprises a first, female connector element 112 and a second, male connector element 114. The male connector element 114 is at least partially insertable into the female connector element 112 to engage the male connector element 114 with the female connector element 112. In this embodiment terminal pins 104 of a battery cell 102 provide the female connector element 112. The terminal pins 104 comprise an annular side wall 121 surrounding and defining a closed bore 122. An internal surface of the bore 122 has retaining features in the form of a female screw thread 134 for retaining engagement with the male connector element 114. The male connector element 112 comprises a contact portion 140 and an insertion portion or insertion element 142. The insertion portion 142 is generally cylindrical and an outer surface of the insertion portion 142 includes retaining features in the form of a male screw thread 150. The male screw thread 150 is configured to engage with the female screw thread 134 to retain the male connector element 114 in engagement with the female connector element 112. The contact portion 140 extends from a first end of the insertion portion 142. In this embodiment the contact portion 140 comprises a cap 162. A diameter of the cap 162 is greater than the diameter of the insertion portion 142 such that the contact portion 140 includes a flange 164 that extends radially outwardly from the insertion portion 142. The cap 162 includes a contact surface 166. In this embodiment the contact surface is an annular surface of the flange 164 that faces in a direction towards the insertion portion 142. In this embodiment a PCB 180 includes a through-hole 186 for receiving each of the terminal pins 104. Each through-hole 186 extends through the PCB 180 between a first surface 182 and an opposite second surface 184. A conductive collar 188 is disposed through each through-hole 186. The collar 188 includes a flange 189 at each of its first and second ends. A first flange 189 extends over a part of the first surface 182 of the PCB surrounding the through-hole 186 and a second flange 189 extends over a part of the second surface 184 of the PCB surrounding the through-hole 186. It will be appreciated that to engage the collars 188 with the PCB 180, each collar 188 has an initially tubular shape. The tubular collar 188 is inserted through the through-hole 186 and each end of the collar 188 is then pressed or crimped against the respective surface of the PCB 180 as illustrated. The collar 188 is made of a conductive material (preferably aluminium), and the first flange 189 forms an electrical contact of the PCB 180 in electrical contact with a conductive trace on the first surface 182. To connect the battery cell 102 to the PCB, the female terminal pins 104 are inserted into the collars 188 from a second side of the PCB. The male connector element 114 is then inserted through the collar 188 and through-hole 186 of the PCB 180 so that the cap 162 is disposed on a first side of the PCB 180. The insertion portion 142 of the male connector element 114 extends into the bore 122 of the female connector element 112 (terminal pin 104). The male connector element 114 is rotated about its axis to engage the complementary screw threads 134, 150. When the screw thread 150 of the male connector element 114 is fully engaged with the screw thread 134 of the female connector element 112 the PCB 180 is clamped between the body of the battery cell 102 and the contact surface 166 ofthe male connector element 114. The contact surface 166 is brought into contact with the first flange 189 of the conductive collar 188 and an electrical connection is therefore formed between the terminal pin 104 and the conductive trace by the connector 110. A third embodiment of a connector 210 is illustrated in Figure 7. This connector 210 is substantially identical to the connector 110 of the second embodiment. In particular, a female connector element 112 is provided by the terminal pin 104 of a battery cell 102 and is identical to the female connector element 112 of the second embodiment. A male connector element 214 of this connector 210 comprises a contact portion 240 and an insertion portion or insertion element 242. The insertion portion 242 is generally cylindrical and an outer surface of the insertion portion 242 includes retaining features in the form of a male screw thread 250. The male screw thread 250 is configured to engage with the female screw thread 134 to retain the male connector element 214 of the connector 210 in engagement with the female connector element 112. The contact portion 240 extends from a first end of the insertion portion 242. In this embodiment the contact portion 240 comprises a cap 262. A diameter of the cap 262 is greater than the diameter of the insertion portion 242 such that the contact portion 240 includes a flange 264 that extends radially outwardly from the insertion portion 242. The cap 262 includes a contact surface 266. In this embodiment the contact surface is an annular surface of the flange 264 that faces in a direction towards the insertion portion 242. In this embodiment a top surface 268 ofthe cap 262, that faces in a direction away from the insertion portion 242, provides a driving feature in the form of a slot 270 for receiving a screwdriver. The connector 210 of this embodiment is engageable with a PCB 80 that is identical to the PCB 80 described in relation to the first embodiment. The PCB 80 includes a through-hole 86 that extends through the PCB 80 between a first surface 82 and an opposite second surface 84. A conductive trace is disposed on the first surface 82 of the PCB 80 and a portion of the conductive trace surrounds the through-hole 86. To connect the battery cell 102 to the PCB 80, the female terminal pins 104 are inserted into the through-holes 86 from a second side of the PCB 80. The male connector element 214 is then inserted through the through-hole 86 so that the cap 262 is disposed on a first side of the PCB 80. The insertion portion 242 of the male connector element 214 extends into the bore 122 of the female connector element 112 (terminal pin 104). The male connector element 214 is rotated about its axis to engage the complementary screw threads 134, 250. This rotation may be driven by engaging a screwdriver in the slot 270 in the cap 262. When the screw threads 134, 250 are fully engaged, the PCB 80 is clamped between the body of the battery cell 102 and the contact surface 266 of the male connector element 214. As the conductive trace of the PCB 80 surrounds the through-hole 86, the contact surface 266 is brought into contact with the conductive trace. An electrical connection is therefore formed between the terminal pin 104 and the conductive trace by the connector 210. A fourth embodiment of a connector 310 is illustrated in Figure 8. This connector 310 is similar to the connector 110 of the second embodiment. The connector 310 comprises a first, female connector element 312 and a second, male connector element 314. The male connector element 314 is at least partially insertable into the female connector element 312 to engage the male connector element 314 with the female connector element 312. In this embodiment terminal pins 304 of a battery cell 302 provide the female connector element 312. The terminal pins 304 comprise an annular side wall 321 surrounding and defining a closed bore 322. An internal surface of the bore 322 has retaining features in the form of a plurality of circumferential ribs and grooves. The male connector element 314 of the connector 310 comprises a contact portion 340 and an insertion portion or insertion element 342. The insertion portion 342 is generally conical and an outer surface of the insertion portion 342 includes retaining features in the form of a plurality of circumferential ribs and grooves. The circumferential ribs and grooves of the insertion portion 342 of the male connector element 314 are configured to engage with the complementary circumferential ribs and grooves of the female connector element 312 to retain the male connector element 314 of the connector 310 in engagement with the female connector element 312. The contact portion 340 extends from a first end of the insertion portion 342. In this embodiment the contact portion 340 comprises a cap 362. A diameter of the cap 362 is greater than the diameter of the insertion portion 342 such that the contact portion 340 includes a flange 364 that extends radially outwardly from the insertion portion 342. The cap 362 includes a contact surface 366. In this embodiment the contact surface is an annular surface of the flange 364 that faces in a direction towards the insertion portion 342. In this embodiment a PCB 180 includes a through-hole 186 for receiving each of the terminal pins 104. Each through-hole 186 extends through the PCB 180 between a first surface 182 and an opposite second surface 184. A conductive collar 188 is disposed through each through-hole 186. The collar 188 includes a flange 189 at each of its first and second ends. A first flange 189 extends over a part of the first surface 182 of the PCB surrounding the through-hole 186 and a second flange 189 extends over a part of the second surface 184 of the PCB surrounding the through-hole 186. The collar 188 is made of a conductive material (preferably aluminium), and the first flange 189 forms an electrical contact of the PCB 180 in electrical contact with a conductive trace on the first surface 182. To connect the battery cell 302 to the PCB 180, the female terminal pins 304 are inserted into the collars 388 from a second side of the PCB 180. The male connector element 314 is then inserted through the collar 188 and through-hole 186 of the PCB 180 so that the cap 362 is disposed on a first side of the PCB 180. The insertion portion 342 of the male connector element 314 extends into the bore 322 of the female connector element 312 (terminal pin 304). The male connector element 314 is pressed into the female connector element 312 (in an axial direction) to engage the complementary ribs and grooves. When the ribs and grooves of the male connector element 314 are fully engaged with the ribs and grooves of the female connector element 312 the PCB 180 is clamped between the body of the battery cell 302 and the contact surface 366 of the male connector element 314. The contact surface 366 is brought into contact with the first flange 189 of the conductive collar 188 and an electrical connection is therefore formed between the terminal pin 304 and the conductive trace by the connector 310. A fifth embodiment of a connector 410 is illustrated in Figure 9. In this embodiment, a male connector element 414 of the connector 410 is provided on a battery cell 402. A contact portion 440 in the form of a cap 462 is connected to an end of each terminal pin 404 of the battery cell 402. A stem of the terminal pin 404 forms an insertion portion or insertion element of the male connector element 414. A diameter of the cap 462 is greater than the diameter of the terminal pin 404 such that the contact portion 440 includes a flange 464 that extends radially outwardly from the terminal pin 404. The cap 462 includes a contact surface 466. In this embodiment the contact surface is an annular surface of the flange 464 that faces in a direction towards a body of the battery cell 402. A female connector element 412 of the connector 410 is provided in a PCB 480. The PCB 480 includes a through-hole 486 for receiving each of the terminal pins 404 of the battery cell 402. Each through-hole 486 extends through the PCB 480 between a first surface 482 and an opposite second surface 484. In this embodiment each though-hole 486 is comma-shaped, having a wider first end 487 and a narrower second end 489. A pair of comma-shaped through-holes 486 is therefore provided to receive the two terminal pins 404 of a single battery cell 402. In this embodiment the through-holes 486 of the pair are arranged such that they extend in opposite directions, and a distance between the first ends 487 of the through-holes 486 is equal to a distance between the second ends 489 of the through-holes 486. A conductive trace 481 is disposed on the first surface 482 of the PCB 480 and a portion of the conductive trace 481 surrounds the through-hole 486. To connect the battery cell 402 to the PCB 480, the terminal pins 404 are inserted through the first, wider ends of the through-holes 486 from a second side of the PCB 480. The terminal pins 404 extend through the through-holes 486 so that the caps 462 are disposed on a first side of the PCB 480. In this embodiment the battery cell 402 is then twisted so that each of the terminal pins 404 moves along its respective through-hole 486 from the first end to the narrower second end. With the terminal pins 404 seated at the second ends of the through-holes 486, the PCB 480 is clamped between the body of the battery cell 402 and the contact surface 466 of the cap 462. As the conductive trace of the PCB 480 surrounds the through-hole 486, the contact surface 466 is brought into contact with the conductive trace. An electrical connection is therefore formed between the terminal pin 404 and the conductive trace. It is envisaged that the connectors of the present invention may be used to connect a plurality of battery cells to a PCB. As described above, the battery cells are connected to the PCB such that the body of each of the battery cells is disposed o a second side of the PCB and an electrical connection is made with a conductive trace on a first surface of the PCB. The connectors of the present invention are, therefore, suitable for use with a battery cell in which both the positive terminal pin and the negative terminal pin extend from the same end of the body of the battery cell. A plurality of battery cells connected to a PCB may form a battery module. The battery module may further comprise a supporting structure or frame. Referring now to Figure 10, an embodiment of a battery module 500 according to the present invention is illustrated. The battery module 500 comprises a plurality of battery cells 502; each battery cell 502 comprising a body 504 and a pair of terminal pins 506 (only one of which is shown) extending from a first end 508 of the body 504. The module 500 further comprises a base plate 510. The base plate 510 comprises a plurality of recesses 512, each recess 512 being sized and shaped to receive a second end 514 of the body 504 of a battery cell 502. An insulating tube 516 is disposed around the body 504 of each battery cell 502 to prevent or minimise lateral movement of the battery cells 502. The insulating tube 516 may be made of silicone. The terminal pins 506 are connected to a PCB 518 as described above using a suitable connector 10, 110, 210, 310, 410, according to the present invention. Atop cover 520 is then placed over the PCB 518 and battery cells 502, and is connected to the base plate 510. In some embodiments the battery cells may be carbon cells. The battery cells and battery module may form part of a battery pack for an electric vehicle. The battery pack may further include sensors and control systems for monitoring a state of each of the battery cells. It will be appreciated that by using a connector according to the invention as described above, a single battery cell may be easily and quickly disconnected from a PCB. This allows a single battery cell to be removed and replaced if a failure or deterioration of that battery cell is detected. This removes the need to replace a complete battery module or battery pack due to the failure of one or a few battery cells. Instead the battery cells may be replaced individually when required, prolonging the overall life of the battery module or battery pack. Other modifications and variations not explicitly disclosed above may also be contemplated without departing from the scope of the invention as defined in the appended claims.

Claims

1. An assembly comprising:a PCB having at least two through-holes extending through the PCB between a first side and an opposite second side, a first surface on the first side of the PCB including at least two conductive traces, a part of each of the conductive traces surrounding a respective through-hole;a battery cell comprising a body, a positive terminal and a negative terminal, both terminals being at a first end of the body; anda cap electrically connected to each of the positive and negative terminals, each cap including a contact surface, and each cap being connected to the respective terminal by an insertion element,wherein each insertion element extends through a respective through-hole of the PCB such that the body of the battery cell is disposed on the second side of the PCB and the contact surface of each cap is in electrical contact with one of the conductive traces.

2. An assembly according to Claim 1, in which each insertion element is permanently attached to or integral with the respective terminal of the battery cell.

3. An assembly according to Claim 1, in which the battery cell comprises a positive terminal pin integral with the positive terminal and extending from the first end of the body and a negative terminal pin integral with the negative terminal and extending from the first end of the body, and wherein each insertion element is engaged with and detachable from the respective terminal pin.

4. An assembly according to Claim 3, in which the cap and insertion element are parts of a male connector element, the male connector element further comprising first retaining features, and the assembly further comprises two female connector elements each having second retaining features, and wherein the first and second retaining features of respective pairs of male and female connector elements are engaged with each other to maintain an electrical connection between the positive and negative terminals of the battery cell and the contact surfaces ofthe caps.

5. An assembly according to Claim 4, in which each of the positive terminal pin and negative terminal pin provide a respective female connector element for receiving the corresponding male connector element.

6. An assembly according to Claim 4, in which each of the female connector elements is in the form of a collar for receiving a part of a terminal pin and a part of a male connector element.

7. An assembly according to Claim 6, in which each male connector element includes a pair of gripping jaws and each female connector element includes a bearing surface, and wherein when the male and female connector elements are engaged with each other the bearing surface applies a force to the gripping jaws to cause the jaws to grip a part of a respective terminal pin of the battery cell.

8. An assembly according to any one of Claims 4 to 7, in which the first and second retaining features are complementary screw threads.

9. An assembly according to any one of Claims 4 to 7, in which the first and second retaining features are complementary interlocking ribs.

10. An assembly according to any one of Claims 1 to 9, in which a conductive collar is mounted in each of the through-holes, and a part of a flange of each conductive collar is in electrical contact with a part of the respective conductive trace surrounding the through-hole, and wherein the contact surface of each cap is in contact with the flange of a respective collar.

11. An assembly according to any one of Claims 1 to 10, in which the battery cell is a carbon battery cell.

12. An assembly according to any one of Claims 1 to 11, comprising a plurality of battery cells, the battery cells being electrically connected to the conductive traceseither in parallel or in series.

13. An assembly according to Claim 12, further comprising:a base plate including a plurality of recesses, each recess for receiving a second end of the body of one of the battery cells;an insulating tube surrounding the body of each battery cell; anda cover extending over the first side of the PCB and connected to the base plate.

14. A battery module for an electric vehicle comprising an assembly according to any one of Claims 1 to 13.

15. A connector for electrically connecting a terminal of a battery cell on a second side of a PCB to a conductive trace on a first side of a PCB, the connector comprising:a male connector element having an insertion portion including first retaining features and a cap extending from the insertion portion including a flange having a contact surface; anda female connector element having a receiving portion including second retaining features, the second retaining features being engageable with the first retaining features to maintain a connection between the male connector element and the female connector element,wherein the insertion portion is sized to extend through a through-hole of a PCB so that, in use, the contact surface is held in contact with said conductive trace, and the female connector element is connectable to or integral with said battery cell terminal, and wherein at least the male connector element is electrically conductive.

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