End plate

Abstract

Aspects of the present invention relate to an end plate (300, 400, 500, 600) suitable for a cell stack (200, 700) of prismatic cells (204), to an electric vehicle battery cell stack (200, 700), to an electric vehicle battery assembly (800) and to a vehicle (100). The end plate (300, 400, 500, 600) comprises a first temperature sensor (302) and a second temperature sensor (304), where the first temperature sensor (302) is located adjacent a first edge (306) of the end plate (300, 400, 500, 600), and the second temperature sensor (304) is located adjacent an edge of the end plate away from the first edge (306). The cell stack (200, 700) may comprise a plurality of cells (204) arranged in parallel, wherein the end plate (300, 400, 500, 600) is configured to be positioned adjacent an endmost cell (2024a, 204n) of the cell stack (200, 700). The end plate (300, 400, 500, 600) of the invention allows for efficient and effective temperature sensing of the cells (204) within the cell stack (200, 700).

Description

[0001] END PLATE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to an end plate. Aspects of the invention relate to an end plate suitable for a cell stack of prismatic cells, to an electric vehicle battery cell stack, to an electric vehicle battery assembly and to a vehicle.

[0004] BACKGROUND

[0005] Battery packs are becoming increasingly popular for automotive applications and various commercial electronic devices because they can generate the required power and they are rechargeable. In electric and / or hybrid vehicles, battery packs may be used to provide vehicle traction. Such battery packs may, for example, comprise prismatic cells such as lithium ion cells. Storing and operating battery packs at preferred operating temperatures is important to allow the battery to operate at optimum performance. Thus, it is useful to monitor the temperature conditions of the battery packs. However, the structure, location, and operating conditions of the battery packs can make it difficult to reliably monitor the temperature of the battery pack and its components.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide an end plate suitable for a cell stack of prismatic cells, an electric vehicle battery cell stack, an electric vehicle battery assembly and a vehicle as claimed in the appended claims.

[0009] According to an aspect of the disclosure, there is provided an end plate suitable for a cell stack of prismatic cells, the end plate comprising a first temperature sensor and a second temperature sensor, the first temperature sensor being located adjacent a first edge of the end plate, and the second temperature sensor is located adjacent an edge of the end plate away from the first edge. In this way, the temperature sensors are positioned to provide temperature information of the maximum and minimum temperatures of the cells in the cells stack.

[0010] According to another aspect of the disclosure, there is provided an end plate suitable for a cell stack of prismatic cells, the cell stack comprising a plurality of cells arranged in parallel, wherein the end plate is configured to be positioned adjacent an endmost cell of the cell stack, wherein the end plate comprises a first temperature sensor arranged to detect a first temperature at a first location on the end plate and a second temperature sensor arranged to detect a second temperature at a second location on the end plate, the first temperature sensor being located adjacent a middle of a first edge of the end plate, and the second temperature sensor being located adjacent an edge of the end plate away from the first edge. In this way, the temperature sensors provide temperature information relating to the upper surface of the cell stack and to an area spaced apart from the upper surface. According to another aspect of the disclosure, there is provided an end plate suitable for a cell stack of prismatic cells, the cell stack comprising a plurality of cells arranged in parallel, wherein the end plate is configured to be positioned adjacent an endmost cell of the cell stack, wherein the end plate comprises a first temperature sensor arranged to detect a first temperature at a first location on the endmost cell and a second temperature sensor arranged to detect a second temperature at a second location on the endmost plate, the first temperature sensor being located adjacent a middle of a first edge of the end plate, and the second temperature sensor being located adjacent an edge of the end plate away from the first edge. In this way, the first temperature sensor provides temperature information relating to the upper surface of the cell stack, and the second temperature sensor provides temperature information relating to an area spaced apart from the upper surface. The inventors have identified that the temperatures at these locations are indicative of the minimum and maximum temperatures of the cell stack.

[0011] In an embodiment, the second temperature sensor is located adjacent a corner of the endplate formed by a second edge and a third edge of the end plate. In this way, the second temperature sensor is located a significant distance from the first temperature sensor.

[0012] Optionally, the end plate may comprise a third temperature sensor arranged to detect a third temperature at a third location on the endmost cell. The third temperature sensor provides improved accuracy in the sensing of the temperatures and provides redundancy should another temperature sensor fail.

[0013] In an embodiment, the third temperature sensor is located adjacent a corner of the end plate formed by the third edge and a fourth edge of the endplate. In this way, the end plate will still provide relevant temperature measurements even if the cell stack is oriented in a way which may affect the minimum and maximum temperature locations.

[0014] According to yet another aspect of the disclosure, there is provided an electric vehicle battery cell stack wherein the at least one electric vehicle battery cell stack comprises an array of prismatic cells; and an end plate as discussed herein. This allows for improved measurement of the temperatures in the electric vehicle battery cell stack.

[0015] According to a further aspect of the disclosure, there is provided an electric vehicle battery cell stack comprising: a first terminating plate; a second terminating plate positioned in opposition to the first terminating plate; an array of prismatic cells between the first terminating plate and second terminating plate, the array comprising a plurality of prismatic cells arranged in parallel; the first terminating plate positioned adjacent an endmost cell at a first end of the array, the second terminating plate is positioned adjacent an endmost cell at a second end of the array; and wherein the first terminating plate is an end plate as described herein. In this way, the temperature of the cell stack may be measured efficiently and accurately to allow for improved operation thereof, including improved longevity of the cells of the cell stack. Where the electric vehicle battery cell stack comprises a terminating plate with the array of cells between the terminating plate and the end plate, the cell stack may be arranged in a number of ways and the end plate will remain accessible.

[0016] The terminating plate may be another end plate as disclosed herein. In this way, temperatures at both ends of the electric vehicle battery cell stack may be measured, providing further detail of the operating temperatures therein.

[0017] Positioning the end plate adjacent to an endmost cell in the array of cells allows the temperature sensors of the end plate to sense the temperature of the end cell of the array. The array of cells of the cell stack may be a longitudinal array. Where the cells are prismatic cells, they may be arranged side by side to form the longitudinal array. Such an arrangement may be referred to as having the cells of the array stacked longitudinally.

[0018] In an embodiment, the end plate is substantially parallel to the endmost cell of the cell stack. This is an efficient and robust construction of the cell stack.

[0019] Optionally, the electric vehicle battery cell stack comprises a first cell temperature sensor arranged to detect a cell temperature of an intermediate cell of the array, the intermediate cell being located between the endmost cells of the array. In this way, a temperature within the cell stack may be measured. This may be useful where the endmost cells do not represent the maximum and minimum temperatures of the cell stack.

[0020] In an embodiment, the electric vehicle battery cell stack comprises a side bracket at the intermediate cell, the side bracket comprising the first cell temperature sensor. This is an efficient manner of positioning the cell temperature sensor. The side bracket may form part of a casing of the intermediate cell.

[0021] Optionally, the first cell temperature sensor is adjacent a negative terminal of the intermediate cell.

[0022] In an embodiment, there are between three and seven cells between the intermediate cell and the endplate. The temperatures of the cells in this range are less likely to be influenced by the components at the end of the electric vehicle battery cell stack, such as the endplate.

[0023] In an embodiment, the electric vehicle battery cell stack comprises a second cell temperature sensor arranged to detect a cell temperature of a further intermediate cell of the array, the further intermediate cell being located between the endmost cells, closer to the second terminating plate than the first terminating plate. In this way, the measurement of temperatures for the electric vehicle battery cell stack is improved and there is flexibility in the arrangement of the electric vehicle battery cell stack. There may be between three and seven cells between the further intermediate cell and the endplate closest thereto. Optionally, the first cell temperature sensor and the second cell temperature sensor are locating on opposing sides of the array. This provides further improvements in the measurement of the temperatures in the cell stack and the flexibility of arrangement of the electric vehicle battery cell stack.

[0024] Optionally, the electric vehicle battery cell stack may comprise a temperature regulation system. The temperature regulation system may have a temperature regulation plate located along a longitudinal axis of the cell stack such that an edge of the temperature regulation plate is adjacent the first edge of the end plate.

[0025] In an embodiment, the electric vehicle battery cell stack may have an exoskeleton extending along its longitudinal axis. Such an exoskeleton provides a robust structure.

[0026] Optionally, the electric vehicle battery cell stack may comprise a Cell Supervisory Circuit (CSC) module mounted on the end plate, wherein the temperature sensors are configured to communicate with the CSC module. In this way, the CSC module can use the temperature information from the temperature sensors for managing the electric vehicle battery cell stack.

[0027] According to a further aspect of the disclosure, there is provided an electric vehicle battery assembly comprising a pair of electric vehicle battery cell stacks as described herein and further comprising a-stack-to- stack bus bar for connecting the pair of electric vehicle battery cell stacks to each other. In this way, a battery assembly having a power output to power an electric vehicle may be provided.

[0028] The stack-to-stack bus bar may provide an electrical connection between the pair of electric vehicle battery cell stacks. In an embodiment, the stack-to-stack bus bar electrically engages the pair of electric vehicle battery cell stacks adjacent their end plates. In this way, a number of stacks may be combined in an efficient and effective manner.

[0029] In an embodiment, the electric vehicle battery assembly may comprise a further stack-to-stack bus bar configured to engage at least one of the cell stacks adjacent to the middle of the length of the cell stacks. In this way, a robust electrical connection may be formed between the cell stacks of the electric vehicle battery assembly.

[0030] According to a still further aspect of the disclosure, there is provided a vehicle. Such a vehicle may be a battery electric vehicle powered by an electric vehicle cell stack according to the disclosure or an electric vehicle battery assembly comprising one or more of the electric vehicle cell stacks according to the disclosure.

[0031] 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.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0034] Fig. 1 shows a vehicle in accordance with an embodiment of the invention;

[0035] Fig. 2 shows a high-level top view of an embodiment of electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0036] Fig. 3 shows an example of an end plate in accordance with an embodiment of the invention;

[0037] Fig. 4 shows another example of an end plate in accordance with an embodiment of the invention;

[0038] Fig. 5 shows a further example of an end plate in accordance with an embodiment of the invention; Fig. 6 shows yet another example of an end plate in accordance with an embodiment of the invention; Fig. 7 shows a perspective view of an electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0039] Fig. 8 shows a perspective view of another example electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0040] Fig. 9 shows a top view of the example electric vehicle battery cell stack shown in Fig. 8;

[0041] Fig. 10 shows an end view of an electric vehicle battery assembly in accordance with an embodiment of the invention;

[0042] Fig. 11 a shows a high-level top view of an embodiment of an electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0043] Fig. 11 b shows a high-level top view of an embodiment of an electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0044] Fig. 12 shows a high-level top view of an embodiment of an electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0045] Fig. 13 shows a side view of an embodiment of an electric vehicle battery cell stack in accordance with an embodiment of the invention;

[0046] Fig. 14 shows an end perspective view of an electric vehicle battery cell stack in accordance with an embodiment of the invention.

[0047] DETAILED DESCRIPTION

[0048] A vehicle 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Fig. 1 . The vehicle 100 may be a battery electric vehicle or hybrid electric vehicle. The vehicle 100 comprises an electric vehicle cell stack 200 according to the disclosure or an electric vehicle battery assembly 800 comprising one or more of the electric vehicle cell stacks 200. The electric vehicle cell stack according to the disclosure has an end plate comprising one or more temperature sensors for determining thermal conditions of an array of cells in the electric vehicle cell stack. With reference to Fig. 2, there is shown an electric vehicle battery cell stack, indicated generally by the reference numeral 200, in accordance with an embodiment of the invention. The electric vehicle battery cell stack 200 comprises an array 202 of prismatic cells 204 and a pair of terminating plates, including a first terminating plate and a second terminating plate. The first terminating plate and the second terminating plate are positioned in opposition to each other. The array of cells 202 is positioned between the pair of terminating plates. The prismatic cells 204 are arranged in a longitudinal array 202. The longitudinal array 202 comprises a first cell 204a at one end thereof, a last cell 204n at the opposing end thereof, and a plurality of cells therebetween. The plurality of cells between the endmost cells may be referred to as intermediate cells. The first cell 204a and the last cell 204 may each also be referred to as an endmost cell. The Each terminating plate is adjacent an endmost cell of the array 202. Each prismatic cell 204 within the array 202 may comprise a pair of electrical terminals (not shown). The terminals may be located on the end faces of the cells 204. The terminals along one side of the array 202 may be electrically connected by a bus bar (not shown). The electric vehicle battery cell stack 200 may comprise a pair of bus bars, one on each side of the array 202, such that each bus bar may engage one terminal of each cell 204 in the array 202. One or more of the bus bars may be implemented as an assembly, for example, an assembly comprising bus bar portions and a bus bar carrier to combine the bus bar portions.

[0049] The pair of terminating plates comprises an end plate 300, as will be described in more detail herein, and a further terminating plate 206. The end plate 300 is positioned adjacent the last cell 204n of the array 202. The further terminating plate 206 is positioned adjacent the first cell 204a of the cell stack 200. The further terminating plate 206 may comprise a second end plate 300, or an alternative terminating plate may be used. The array 202 of cells 204 may be secured between the two terminating plates. The terminating plates can be referred to as cell securing plates, endcaps or other suitable terms.

[0050] The electric vehicle battery cell stack 200 may comprise an exoskeleton (not shown) surrounding the array 202 of prismatic cells 204. In an example, the exoskeleton may comprise longitudinal structural elements extending the length of the array 202. The longitudinal structural elements may be connected to the terminating plates. The longitudinal structural elements may include one or more planar brackets, and / or one or more L- shaped brackets having one portion thereof extending along the top or base of the array 202 and one portion extending along the side. It will be understood that other configurations of structural elements are within the scope of the disclosure.

[0051] The end plate 300 comprises one or more temperature sensors for determining thermal conditions of the array 202 of cells 204. The temperature sensors are suitable for sensing the temperature of the cell closest to the end plate 300. As shown in Fig. 2, the last cell 204n in the array 202 is closest to the end plate 300. If the second terminating plate 206 is also an end plate 300, then the closest cell thereto is the first cell 204a. Each temperature sensor may be configured to sense the temperature of a region of the cell adjacent thereto, wherein the region comprises the portion of the cell substantially parallel to the temperature sensor and may include the surrounding area of the cell. In this way, the temperature data from the one or more temperature sensors may be used to determine temperature information for other areas of the last cell 204n, and / or for other cells within the array. In an example, the temperatures of the first cell 204a and the last cell 204n may be indicative of the extremes of temperatures within the array 202 of cells 204. In a particular example, the temperature of the endmost cell 204n is indicative of the extremes of temperatures within the array 202. In this way, if the temperatures at the first and last cells are within desired operating conditions for the cell stack, it can be understood that the temperatures of all the intervening cells are also within desired operating conditions.

[0052] The end plate of the present disclosure allows the temperature of the cells in the array to be monitored in a convenient manner and avoiding installing temperature sensors in or between cells in the array.

[0053] With reference to Fig. 3, there is shown a semi-schematic of an end plate 300 suitable for use in a cell stack of prismatic cells, such as that described in relation to Fig. 2. The end plate 300 comprises a first temperature sensor 302 and a second temperature sensor 304. The first temperature sensor 302 is located adjacent the middle of a first edge 306 of the end plate 300. The second temperature sensor 304 is located away from the first edge, and may be located adjacent another edge 308 of the end plate 300. The end plate 300 is suitable for a cell stack 200 of prismatic cells 204, the cell stack 200 comprising a plurality of cells 204 arranged physically in parallel. The end plate 300 is suitable to be positioned adjacent an endmost cell 204a, 204n of the cell stack 200. It will be understood that the locations of the temperature sensors are not limited to those illustrated and / or described in the present disclosure.

[0054] The end plate 300 is substantially rectangular in shape, having an upper edge 306, a lower edge 308, a left edge 310 and a right edge 312. The end plate 300 has a first corner 314 between the upper edge 306 and the left edge 310, a second corner 316 between the upper edge 306 and the right edge 312, a third corner 318 between the lower edge 308 and the right edge 312, and a fourth corner 320 between the lower edge 308 and the left edge 310. The first temperature sensor 302 is arranged to detect a first temperature at a first location on the endmost cell adjacent the end plate 300. The first location as illustrated in Fig. 3 is adjacent the middle of the upper edge 306. The second temperature sensor 304 is arranged to detect a second temperature at a second location on the endmost cell adjacent the end plate 300. The second location as illustrated in Fig. 3 is towards the lower edge 308. Each of the first temperature sensor 302 and the second temperature sensor 304 may be configured to communicate their sensor data. They may be configured to communicate the sensor data to a monitoring system for the electric vehicle battery cell stack. They may be configured to communicate in a wired or wireless manner. In some examples, the temperature sensors 302, 304 are fitted to corresponding apertures in the end plate 300 such that they are close enough to the endmost cell 204a, 204n of the array 202 to accurately sense its temperature. The sensors 302, 304 may be in contact with the endmost cell 204a, 204n. Positioning the temperature sensors and their associated apertures adjacent the edges of the end plate 300 is useful in supporting the strength and rigidity of the end plate 300.

[0055] With reference to Fig. 4, there is shown a semi-schematic of another example of the end plate shown in Fig. 3. The end plate 400 of Fig. 4 is similar to that shown in Fig. 3, and like reference numerals will be used for like parts. The end plate 400 comprises a first temperature sensor 302 and a second temperature sensor 304. The first temperature sensor 302 is located adjacent the middle of the first edge 306 of the end plate 400, where the first edge is the upper edge 306 as illustrated. The second temperature sensor 304 is located adjacent the fourth corner 320 of the end plate 400 formed by the left edge 310 and the lower edge 308. The second temperature sensor 304 could alternatively be located adjacent to the third corner 318 formed between the lower edge 308 and the right edge 312. Locating one or more of the temperature sensors near the side edges 310, 312 of the end plate 400 allows sensing of temperature increases near the terminals of the endmost cell(s) 204a, 204n of the array 202.

[0056] With reference to Fig. 5, there is shown a semi-schematic of a further example of the end plate shown in Fig. 3. The end plate 500 of Fig. 5 is similar to that shown in Figs. 3 and 4, and like reference numerals will be used for like parts. The end plate 500 comprises a first temperature sensor 302, a second temperature sensor 304, and a third temperature sensor 505. The third temperature sensor 505 is arranged to detect a third temperature at a third location on the on the endmost cell adjacent the end plate 500. The first temperature sensor 302 and second temperature sensor 304 are located in the same locations as in the end plate 400 of Fig. 4. The third temperature sensor is located adjacent to the third corner 318 formed between the lower edge 308 and the right edge 312. It will be understood that the end plate may comprise further temperature sensors, however, the inventors have discovered that three temperature sensors provide accurate temperature indications for the stack and redundancy in the temperature sensing. The symmetric positioning of the second temperature sensor 304 and third temperature sensor 505 provides versatility when arranging the electric vehicle battery cell stacks 200.

[0057] With reference to Fig. 6, there is shown a semi-schematic of an example of the end plate shown in Fig. 5. The end plate 600 of Fig. 6 has a Cell Supervisory Circuit (CSC) module 602 mounted thereon. The CSC module 602 is configured to control the operation and output of the cells 204 and electric vehicle battery cell stack 200. In this way, the sensor output data of the temperature sensors may be communicated to the CSC module 602. In Fig. 6, the second temperature sensor 304 is shown having a wired electrical connection to the CSC module 602, which may be used to communicate its sensor data to the CSC module 602. The third temperature sensor 505 is shown with a wireless connection to the CSC module 602, which may be used to communicate its sensor data to the CSC module 602. It will be understood that the temperature sensors 302, 304, 505 may be wired or wireless devices, and an end plate according to the disclosure may include one or more wired sensor and / or one or more wireless sensor. The CSC module 602 may also communicate with a CSC module of another electric vehicle battery cell stack 200, or other device, and may communicate in a wired or wireless manner.

[0058] With reference to Fig. 7, there is shown an example of an electric vehicle battery cell stack, indicated generally by the reference numeral 700. The electric vehicle battery cell stack 700 is illustrated as comprising an end plate 500 as described herein in relation to Fig. 5, which in turn comprises a first temperature sensor 302, a second temperature sensor 304, and a third temperature sensor 505. However, it will be understood that any of the other end plates 300, 400, 600 described herein may be used in the electric vehicle battery cell stack 700 instead. As described previously in relation to Fig. 2, the electric vehicle battery cell stack 700 comprises an array 200 of prismatic cells stacked longitudinally, such that in Fig. 7, the array of cells extends rearwardly from the end plate 500. The opposite end (not shown) of the electric vehicle battery cell stack 700 may comprise any of the other end plates 300, 400, 500, 600 described herein or another suitable terminating plate. The electric vehicle battery cell stack 700 comprises a temperature regulation system for managing the temperature of the array of cells. The temperature regulation system may provide heating and cooling of the array 202. The temperature regulation system includes a temperature regulation plate 702 located along the longitudinal axis. In the example shown in Fig. 7, the temperature regulation plate 702 is located along on the top of the electric vehicle battery cell stack 700, centred substantially along the longitudinal axis. As the temperature regulation plate 702 is located on the top of the electric vehicle battery cell stack 700, its end closest to the end plate 500 is close to the upper edge 306 of the end plate, and is thus close to the first temperature sensor 302, and not close (relative to the size of the end plate) to the second temperature sensor 304 or third temperature sensor 505.

[0059] The temperature regulation system may use a temperature regulating fluid to adjust the temperature of the array 202, and may include spigots to operate as an inlet and an outlet for the temperature regulating fluid. The temperature regulation plate 702 may comprise a fluid path for the temperature regulating fluid from inlet to outlet. The inlet for the temperature regulating fluid may be located adjacent to the last cell 204n, such that the last cell 204n is the cell closest to the inlet. The outlet for the temperature regulating fluid may be located adjacent to the other end of the array 202 of cells 204, such that it is closest to the first cell 204a. As the temperature regulating fluid flows along the array 202, it increases or decreases in temperature progressively (by picking-up or imparting heat to each cell). In this way, the temperature regulating fluid in the temperature regulation plate 702 will have its extreme temperatures (max or min) at the ends of the array 202 where the spigots are located. The difference in temperature between the temperature regulating fluid and the cells 204 of the array 202 gradually reduces from inlet to outlet. As such, the heat transfer between the temperature regulation plate 702 and the cells 204 may reduce as the temperature regulating fluid moves from the inlet towards the outlet of the array 202.

[0060] It will be understood that Fig. 7 shows only one example of a temperature regulation system and one example of the size and arrangement of the temperature regulation plate 702, and that other arrangements may be used.

[0061] The inventors have identified that the first temperature sensor 302 in the first location can provide a useful indication of the high and low temperatures of the cells within the electric vehicle battery cell stack 700. In an example, the first temperature sensor 302 provides an indication of the maximum temperature within the cells when the temperature regulation plate 702 is heating the array 202, and provides an indication of the minimum temperature within the cells when the temperature regulation plate 702 is cooling the array 202.

[0062] The inventors have further identified that positioning the second temperature sensor 304, and third temperature sensor 505 where included, adjacent the corner of the end plate 300, 400, 500, 600 spaced apart from the upper edge end plate, provides an indication of the minimum temperature within the cells 204 when the temperature regulation plate 702 is heating the array 202, and provides an indication of the maximum temperature within the cells 204 when the temperature regulation plate 702 is cooling the array 202.

[0063] In use, areas of the cells 204 within the array 202 may experience temperature increases. These areas may be referred to as hot spots. The location of hot spots may be dependent on a number of factors, including electrical load, state of charge of the cells, the operation of the temperature regulation system, and heat sinking provided by other components of the electric vehicle cell stack 700 such as bus bars, structural components and the like. In an example, when the electric vehicle cell stack 700 is operating at high electrical load, the hot spots may be located close to the terminals of the cells 204. When the electric vehicle cell stack is operating at low electrical load, hot spots may arise in different locations.

[0064] With reference to Fig. 8 and Fig. 9, there is shown perspective and top views respectively of a further example of the electric vehicle battery cell stack 700, wherein the electric vehicle battery cell stack 700 of Fig. 8 comprises a plurality of stack-to-stack bus bars 704 for electrically connecting the electric vehicle battery cell stack 700 to adjacent electric vehicle battery cell stacks 700. On one side of the top of electric vehicle battery cell stack 700, a pair of stack-to-stack bus bars 704a, 704b are located close to each other in the middle lengthways of the array of the electric vehicle battery cell stack 700. On the other side of the top of electric vehicle battery cell stack 700, a second pair of stack-to-stack bus bars 704c, 704d are located spaced apart from each other such that each is close to one end of the array. The stack-to-stack bus bars 704 enable connection to the bus bars of adjacent electric vehicle battery cell stacks. The stack-to-stack bus bars 704 may be welded to bus bars (not shown) running along the side of the array of prismatic cells forming the electric vehicle battery cell stack 700.

[0065] Referring now to Figure 10, there is shown a block diagram of an electric vehicle battery assembly 800 suitable for an electric vehicle, for example as a traction battery thereof. The electric vehicle battery assembly 800 comprises a plurality of electric vehicle battery cell stacks 700. Alternate electric vehicle battery cell stacks 700 may be flipped and rotated such that the base, as illustrated herein, of one electric vehicle battery cell stack 700 is on top of the base of another electric vehicle battery cell stack 700. In this way, the end plate 600 having a CSC module 602 may be at opposite ends of adjacent electric vehicle battery cell stack 700. The opposite end of the electric vehicle battery cell stack 700 may comprise another end plate, such as the end plate 500 of Fig. 5, or another suitable terminating plate. The end plates shown in Fig. 10 correspond to the end plate 600 described herein in relation to Fig. 6 and the end plate 500 described herein in relation to Fig. 5. Such an electric vehicle battery assembly 800 may be installed in the vehicle 100 shown in Figure 1 .

[0066] Thermal insulation (not shown) may be positioned between the end plate 300 and the closest cell 204a, 204n thereto. In this way, influence from the end plate on the temperature of the end cells 204a, 204n is reduced, and in some examples, the end plate 300 does not influence the temperature of the end cells 204a, 204n.

[0067] The endplate may be manufactured from a number of different materials, for example, metal, plastic, ceramic, a composite, or the like. The factors to be considered in choosing a material for the end plate include structural suitability, electrical suitability, thermal suitability, manufacturing suitability, and cost suitability. As will be understood, a chosen material may represent a balance across the many issues to be considered, where some issues are prioritised over others.

[0068] In the examples of the electric vehicle battery cell stack described heretofore, the temperature sensors are located such that they are not thermally affected by the presence of the endplate. For example, the end plate 300 may be thermally insulated from the array of cells or it may be manufactured from a material that reduces or prevents its operation as a heatsink for the array of cells. As discussed previously, under certain operating conditions, the maximum temperature of the array may be in the cell 204n next to the end plate, However, in some examples, the end plate may have an effect on the temperature of the cells closest to it, for example, by acting as a heatsink and thus reducing the temperature of the last cell 204n. Some examples of the electric vehicle battery cell stack according to the disclosure include a temperature sensor on the side of the cell stack at an intermediate cell of the array. Such a cell temperature sensor can be used to measure the temperature of a cell that is thermally unaffected by the endplate.

[0069] Referring now to Figs. 11 a and 11 b, there is shown partial top views of an electric vehicle battery cell stack, indicated generally by the reference numeral 900. The electric vehicle battery cell stack 900 of Figs. 11 a and 11 b is similar to those described herein previously and like reference numeral numbers are used for like parts. The electric vehicle battery cell stack 900 comprises the array 200 of cells 204. There are a plurality of temperature sensors arranged to measure the temperature of the array 200 of cells 204, including a first temperature sensor 302 and a second temperature sensor 304 at a first end of the array, and a first cell temperature sensor 902 at a side of the array 200. The temperatures sensors 302, 304 and 902 may be in contact with the cells 204 the temperature of which they are measuring. In the example shown in Figs. 11 a and 11 b, the temperature sensors 302, 304 and 902 are not visible from a top view, and as such they are shown in dotted lines. The first cell temperature sensor 902 is arranged to detect a cell temperature of an intermediate cell 204x of the array 200.

[0070] The electric vehicle battery cell stack 900 may comprise a side bracket 904 at the intermediate cell 204x, the side bracket comprising the first cell temperature sensor 902. The side bracket 904 may comprise an aperture for receiving the first cell temperature 902 and through which the first cell temperature sensor 902 measures the temperature of the intermediate cell 204x, for example by being in contact with the cell 204x. The first cell temperature sensor 902 may be positioned at the end of the intermediate cell having the negative terminal of the cell 204x.

[0071] As shown in Figs. 1 1 a and 11 b, there are four cells between the intermediate cell 204x and the end plate 300 (not including the intermediate cell 204x). In examples, there are between three and seven cells between the intermediate cell 204x having the first side temperature sensor 902 and the end plate 300. In this way, the intermediate cell 204x provides an indication of the temperature of cells within the array, away from the effect of the end plate.

[0072] Referring now to Fig. 12, there is shown a top view of an example of an electric vehicle battery cell stack, indicated generally by the reference numeral 950, in accordance with the disclosure. The electric vehicle battery cell stack 950 comprises an array 202 of cells 204 as described previously. The array 202 of cells 204 is located between a pair of end plates 300a, 300b as described previously. The first end plate 300a is beside the last cell 204n while the second end plate 300b is beside the first cell 204a. Each of the end plates 300a, 300b comprises two temperature sensors, first temperature sensors 302a, 302b located in the middle of the top edge of the end plates 300a, 300b and second temperature sensors 304a, 304b located at one corner of the lower edge of the end plates 300a, 300b. The array 202 of cells 204 comprises a first intermediate cell 204x and a second intermediate cell 204y. The first intermediate cell 204x is the fifth cell from the first end plate 300a, such that there are four cells between the first intermediate cell 204x and the first end plate 300a. The second intermediate cell 204y is the fifth cell from the second end plate 300b, such that there are four cells between the second intermediate cell 204y and the second end plate 300b. As with the electric vehicle battery cell stack 900 described in relation to Figs. 11 a and 11 b, the electric vehicle battery cell stack 950 of Fig. 12 has a first cell temperature sensor 902 at the first intermediate cell 204x. Additionally, the electric vehicle battery cell stack 950 has a second cell temperature sensor 906 at the second intermediate cell 204y. The second cell temperature sensor 906 is located in a second bracket 908 at the end of the second intermediate cell 204y. The second cell temperature sensor 906 may be on the end of the intermediate cell 204y having the positive terminal thereon. The second bracket 908 is similar to the side bracket 904 described in relation to Fig. 11 b. As shown on the side of the electric vehicle battery cell stack 950, each cell may have a bracket. The bracket may form part of the cell casing. In embodiments of the invention, each end plate 300a may comprise only one temperature sensor 302a, 302b, 304a, 304b. Each end plate 300a temperature sensor may be located in the middle of the top edge of the end plates 300a, 300b, or alternatively at one corner of the lower edge of the end plates.

[0073] Referring now to Fig. 13, there is shown a side view of an electric vehicle battery cell stack according to the disclosure such as the electric vehicle battery cell stack 900 as described in relation to Fig. 1 1 . Fig. 13 shows a portion of the array 200 of cells 204, an endplate 300, and a terminating plate 206. The first temperature sensor 302 and second temperature sensor 304 are shown at the intersection of the end plate 300 and last cell 204n. The first cell temperature sensor 902 is also shown, at the side of the intermediate cell 204x. The first cell temperature sensor 902 is located in an aperture 960 in the side of the intermediate cell. The aperture 960 may be an aperture in a casing of the cell 204.

[0074] Referring now to Fig. 14, there is shown an end perspective view of an electric vehicle battery cell stack 750 according to an embodiment of the invention, where features previously described herein in relation to previous figures are labelled with their existing reference numerals, including an end plate 600 having the first temperature sensor 302, the second temperature sensor 304, and the third temperature sensor 505; the CSC module 602, the temperature regulation plate 702; and the stack-to-stack bus bar 704d. In the end plate 600 shown in Fig. 11 , the temperature sensors 302, 304, 505 themselves cannot be seen, as they are fitted with covers. The covers may be referred to as clips or formers. A spigot 706 forming part of the temperature regulating system is shown at a corner of the temperature regulation plate 702. The spigot 706 is adjacent to the stack-to-stack bus bar 704d and above the second temperature sensor 304.

[0075] Throughout the description, the temperature sensors may comprise a thermistor or other suitable temperature sensing component. The present disclosure relates to an electric vehicle battery cell stack comprising an array of cells, the electric vehicle battery cell stack having a plurality of temperature sensors in contact therewith, which may include a temperature sensor at a first end of the array and another temperature sensor at a side of the array. The temperature sensor at the end of the array is located in an end plate of the array of cells.

[0076] Throughout the description, features and components may be referred to as “upper”, “lower”, “right”, “left” and so on, however it will be understood that these terms refer only to the figures being described and not intended to indicate that the components, features etc must be location in any specific position or orientation in implementations of the invention.

[0077] It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1 . An end plate suitable for a cell stack of prismatic cells, the cell stack comprising a plurality of cells arranged in parallel, wherein the end plate is configured to be positioned adjacent an endmost cell of the cell stack, wherein the end plate comprises: a first temperature sensor arranged to detect a first temperature at a first location on the endmost cell and a second temperature sensor arranged to detect a second temperature at a second location on the endmost cell, the first temperature sensor being located adjacent a middle of a first edge of the end plate, and the second temperature sensor being located adjacent an edge of the end plate away from the first edge.

2. An end plate as claimed in claim 1 , wherein the second temperature sensor is located adjacent a corner of the end plate formed by a second edge and a third edge of the end plate.

3. An end plate as claimed in claim 1 or 2, comprising a third temperature sensor arranged to detect a third temperature at a third location on the endmost cell, the third temperature sensor being located adjacent a corner of the end plate formed by the third edge and a fourth edge of the endplate.

4. An electric vehicle battery cell stack comprising: a first terminating plate; a second terminating plate positioned in opposition to the first terminating plate; an array of prismatic cells between the first terminating plate and second terminating plate, the array comprising a plurality of prismatic cells arranged in parallel; the first terminating plate positioned adjacent an endmost cell at a first end of the array, the second terminating plate is positioned adjacent an endmost cell at a second end of the array; wherein the first terminating plate is an end plate according to any preceding claim.

5. An electric vehicle battery cell stack as claimed in claim 4, comprising a first cell temperature sensor arranged to detect a cell temperature of an intermediate cell of the array, the intermediate cell being located between the endmost cells of the array.

6. An electric vehicle battery cell stack as claimed in claim 5, comprising a side bracket at the intermediate cell, the side bracket comprising the first cell temperature sensor.

7. An electric vehicle battery cell stack as claimed in any of claims 5 or 6 wherein there are between three and seven cells between the intermediate cell and the endplate.

8. An electric vehicle battery cell stack as claimed in any of claims 4 to 7 wherein the second terminating plate is an endplate according to any of claims 1 to 3.

9. An electric vehicle battery cell stack as claimed in any of claims 4 to 8 comprising a second cell temperature sensor arranged to detect a cell temperature of a further intermediate cell of the array, the further intermediate cell being located between the endmost cells, closer to the second terminating plate than the first terminating plate.

10. An electric vehicle battery cell stack as claimed in claim 9 wherein the first cell temperature sensor and the second cell temperature sensor are locating on opposing sides of the array.11 . An electric vehicle battery cell stack as claimed in any of claims 4 to 10, wherein the cell stack comprises a temperature regulation system having a temperature regulation plate located along the array, such that an edge of the temperature regulation plate is adjacent the first edge of the end plate.

12. An electric vehicle battery assembly comprising, a pair of electric vehicle battery cell stacks of claim 4 to 11 and further comprising a stack-to-stack bus bar for connecting the pair of electric vehicle battery cell stacks to each other, wherein the stack-to-stack bus bar electrically engages the pair of electric vehicle battery cell stacks adjacent their end plates.

13. An electric vehicle battery assembly as claimed in claim 9 or 10, comprising a further stack-to-stack bus bar configured to electrically engage at least one of the cell stacks adjacent to the middle of the length of the cell stacks.

14. An electric vehicle battery assembly as claimed in any of claims 9 to 11 , wherein one of the electric vehicle battery cell stacks is oriented inversely to the other.

15. A vehicle comprising the electric vehicle battery assembly of claims 9 to 12.

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