SE2250626A1

SE2250626A1 - Integrated sensor in a battery module

Info

Publication number: SE2250626A1
Application number: SE2250626A
Authority: SE
Inventors: Csaba Dobi; Mirko Stadel; Rodyn Gilharry
Original assignee: Northvolt Ab
Priority date: 2022-05-25
Filing date: 2022-05-25
Publication date: 2023-11-26
Also published as: WO2023227645A1

Abstract

Disclosed herein is a frame part for a battery module frame, comprising a height extending between an upper face and a lower face, and a thickness extending between an inner face and an outer face. The frame wall further comprises a sensor at least partially integrated into the frame wall. The sensor comprises a sensing portion for sensing characteristics of a secondary cell adjacent to the frame wall, a connection portion for connecting to a sensing circuit; and an intermediate portion for connecting the sensing portion to the connection portion. The sensing portion is arranged at the inner face, the connection portion is arranged at the upper face, and the intermediate portion is enclosed by the frame wall.

Description

Technical Field The present disclosure relates to battery modules. ln particular, the present disclosure relates to a frame wall for a battery module having an integrated sensor.

Background Rechargeable or secondary batteries (cells) find widespread use as electrical power supplies and energy storage systems. For example, in automobiles, battery packs formed of a plurality of battery modules, wherein each battery module includes a plurality of electrochemical cells, are provided as a means of effective storage and utilization of electric power.

Battery modules may comprise a module frame, which may include side walls and end walls, that surrounds or contains a stack of secondary cells. The module frame may advantageously provide structure to the battery module. The module frame may be expected to handle external stresses, such as impacts or collisions, as well as internal stresses, such as a swelling of the secondary cells (leading to compressive forces).

Battery modules may also comprise a variety of sensors such as temperature, pressure, and/or compression (swelling) sensors, for monitoring the health of the secondary cells. Using data collected by such sensors, a battery module can adapt its operation accordingly, or report faults or failures promptly to a management interface, without requiring physical inspection. Therefore, sensors play an important role in the operation and maintenance of battery modules.

Sensors are typically placed between or on top of secondary cells in a stack, for example as part of an electrical management layer of a battery module. That is, sensors are commonly introduced into a battery module, during manufacture thereof, at the same time or after introduction of the secondary cells into a cell space defined by the module frame.

Summary lt is realized as part of the present disclosure that the placement of sensors in the cell space of a battery module, i.e., the space defined by the module frame where cells can be arranged, may reduce the overall energy density of the battery module. lt is further realized as part of the present disclosure that sensors may be damaged during faults or failures of secondary cells (such as a thermal runaway event), or as a result of impacts, collisions, and the like incident upon the battery module. Damage to the sensors may then lead to inaccurate data collection, which may lead to an incorrect assessment that a secondary cell has failed or, potentially worse, a failed detection of a failed secondary cell.

Whilst protective housings for the sensors may reduce the risk of damage thereto, such housings will further reduce the amount of cell space in the battery module being used to contain secondary cells if placed into the cell space, and increase the weight of the battery module, and therefore further reduce the overall energy density of the battery module. ln order to overcome at least these shortcomings, the present disclosure provides a frame wall for a battery module frame that has a sensor integrated therein. ln particular, according to an aspect of the present disclosure, there is provided a frame part (e.g. wall(s) or a portion thereof) of a battery module frame, comprising a height extending between an upper face and a lower face, and a thickness extending between an inner face and an outer face. The frame wall may be any suitable shape to form part of a battery module frame. The terms 'upper' and 'lower' face are not intended to refer to every instantaneous orientation of the battery module, but are instead provided as convenient labels. As alternative labels. lt will be appreciated from the below description of the integrated sensor that other labels for these faces (or at least the upper face) may be equally as appropriate.

The frame wall may comprise a sensor at least partially integrated into the frame wall, as used herein, the term 'integrated' may refer to an enclosure 3 within the frame wall, such that the sensor may be physically confined within the outer dimensions of the frame wall.

The sensor may comprise a sensing portion for sensing characteristics of a secondary cell adjacent to the frame wall. The sensing portion may be a temperature sensor, a pressure sensor, a compression sensor, or any other type of component for sensing characteristics of a secondary cell.

The sensor may further comprise a connection portion for connecting (i.e. an electrical and/or data connection) to a sensing circuit. The sensing circuit may be arranged over the cells in the battery module, or at least closer to what is referred to herein as the upper face of the frame wall than any other face of the frame wall. The sensing circuit may be configured to collect data about the cells in a battery module from one or more sensors in the battery module.

The sensor may further comprise an intermediate portion for connecting the sensing portion to the connection portion. The connection between the sensing portion and the connection portion may be structural, data, and/or electrical, such that data collected about a cell can be collected by the sensing portion, passed to the connection portion via the intermediate portion, and obtained by the sensing circuit from the connection portion.

The sensing portion may be arranged at the inner face, and the connection portion is arranged at the upper face, and the intermediate portion may be enclosed by the frame wall, thereby integrating the sensor within the frame wall. As used herein, a component being arranged 'at' a part of the frame wall is intended to mean that said component is on, nearest, or substantially aligned with (allowing for some protrusion or recession from) said part of the frame wall. lf it is expected that a cell is to be arranged adjacent to the inner face of the frame wall, then the sensing portion may advantageously be arranged at a closest position thereto. Similarly, if it is expected that the sensing circuit is to be arranged proximal to the upper face of the frame wall, then the connection portion may advantageously be arranged at a closest position thereto. As such, the path in between the connection portion and the sensing 4 portion (taken by the intermediate portion of the sensor) can be routed through/within the frame wall.

Hence, a minimal amount of sensor may be exposed to an outside of the frame wall, thereby protecting the various portions of the sensor (especially the intermediate portion) from mechanical, thermal, or other stresses that could affect the sensor in the battery module.

According to such an arrangement, cells in a module may also be allowed to expand (or 'swell') and contract during charging and discharging cycles without being impeded by the presence of a sensor. That is, by integrating the sensor into the frame wall (e.g., instead of sandwiching the sensor between cells or between an end cell and a frame wall), the cells may be afforded an even and uniform surface (e.g. the frame wall surface) against which an even pressure can be exerted during cell expansion. Thus, no pressure 'hotspots' may be caused during cell cycling, which can adversely affect the performance of cells.

Furthermore, the integration of the sensor within the frame wall may advantageously allow for a greater amount of cell space within the module frame to be used for cells. Therefore, the energy density of the battery module may be increased. ln some examples, the sensor may comprise a sensor housing configured for aiding integration of the sensor into the frame wall. For example, the sensor housing may enable an automated (e.g. enacted by autonomous machines) or manual (e.g. enacted by a human manufacturer) introduction of the sensor into the frame wall. The sensor housing may provide additional structure and/or protection to the sensor and portions thereof.

According to some examples, the frame wall may comprise biasing means (or biasing member) configured to bias the sensing portion of the sensor towards the secondary cell. The biasing means may, for example, be formed as part of the sensor housing.

Therefore, characteristics of a cell or cells may be more accurately determined because of an improved and maintained proximity of the sensing portion of the sensor against the cell. ln an example where the sensor comprises a temperature sensor, it can be ensured using a biasing means that a shortest thermal path between a heat-generating part of a cell (e.g. an electrode stack therein) and the sensing portion is maintained.

According to some examples, the sensing portion may be configured to form a flush profile with the inner face, and/or the connection portion may be configured to form a flush profile with the upper face. Thus, the integrated sensor may not interfere with the structure of the battery module and/or the module frame, and the sensor may be protected from internal or external impacts or other stresses.

The frame wall may be configured with an opening extending between the upper face and the inner face, for introduction of the sensor. That is, the opening may allow for the insertion (and, in some examples, retention) of the sensor. ln other examples, opening may only extend partially through the frame wall, and/or the sensor may fill an internal space of the frame wall such that the opening is sealed.

The sensor may comprise any number of sensing portions, which may be arranged at a plurality of locations on the inner face of the frame wall, e.g. to correspond to a plurality of locations on a cell to be sensed.

Furthermore, according to some examples, the sensor may comprise a (further) sensing portion, for sensing characteristics of a secondary cell, that is arranged at the outer face (e.g. if a cell is adjacent to the outer face). ln such examples, the intermediate portion may be further configured for connecting the further sensing portion to the connection portion, or a further intermediate portion for such a purpose may be provided.

According to such examples, the frame wall may have an integrated sensor for sensing characteristics of cells arranged on both sides of the frame wall. Therefore, the space occupied by sensors may be further reduced, as multiple sensors may be incorporated into a single structure.

A module frame may be formed of a pair of side walls and a pair of end walls, such that cells contained in a battery module may be aligned in a stack between the pair of end walls. ln some examples, the above-described frame 6 wall may be at least one (or both) of the pair of end walls. ln other examples, said frame wall may be one or both of the side walls. lt will be appreciated that the so-called 'end' walls may be arranged at ends of a stack of cells but may not necessarily form an end of a module frame, e.g., if the module frame is intended to contain a plurality of stacks of cells.

The above described frame wall, having an integrated sensor, may be manufactured in any suitable way. However, it may be preferable in some examples to provide the frame wall with a cavity for receiving the sensor, and introduce the sensor into the cavity (either during manufacture of the frame wall or after). ln some examples, the cavity may extend all of the way through the frame wall, so as to form an opening extending between the inner face and the upper face, configured for introduction of the sensor. ln other examples, the cavity may not extend all of the way through the frame wall, although the cavity may be formed into such an opening by a further manufacturing step such as drilling, etching, or similar. ln some examples, the cavity may be formed after manufacture of the frame wall, e.g. by drilling or etching, etc., and in other examples, the cavity may be integrally formed with the frame wall, i.e. during a same manufacturing step. For example, an extrusion process may be performed to manufacture the frame wall with one or more cavities suitable for, or configured for, introduction of the sensor.

The sensor may itself be adapted for introduction and integration into a frame wall. For example, various portions of the sensor may be adapted for beneficial properties such as ﬂexibility (for aid of introduction into a cavity), size, and/or resilience. A sensor housing may be introduced for at least a portion of the sensor to aid said adaptation of the sensor for better integration. ln some examples, the sensor may be added into the frame wall during a manufacturing process for manufacturing the frame wall. ln such examples, the sensor may be more resiliently integrated within the frame wall. 7 Frame walls may be retrofitted with sensors so as to realize the above described advantages, or frame walls of existing module frames may be replaced to introduce replacement frame walls having integrated sensors, as described herein. ln any event, numerous advantages, some of which are described above, may be realized through integration of at least part of a sensor into a frame wall of a battery module. These advantages, as well as others, may be further appreciated through a description of specific illustrated embodiments, all of which fall within the scope of the present disclosure.

Brief Description of the Drawings One or more embodiments will be described, by way of example only, and with reference to the following figures, in which: Figure 1 schematically shows a top view of a battery module comprising a plurality of cells, having an integrated sensor in its module frame, according to an embodiment; Figure 2 schematically shows a face-on view of an inner face of a frame wall having an integrated sensor, according to an embodiment; Figures 3A and 3B schematically show cross-sectional views of a frame wall having an integrated sensor, according to an embodiment; Figure 4 schematically shows a cross-sectional view of a sensor adapted for integration into a frame wall, according to an embodiment; Figure 5 schematically shows a cross-sectional view of a frame wall having an integrated sensor with multiple sensing portions, according to an embodiment; Figures 6A and 6B schematically show, using cross-sectional views, example methods for introducing a sensor into a frame wall, according to an embodiment; Figure 7A shows face-on views of inner and outer faces of an example frame wall; Figure 7B shows a perspective view of a sensor adapted for integrating into the example frame wall shown in figure 7A; 8 Figure 7C schematically shows a cross-sectional view and a face-on view of the sensing portion of the sensor shown in figure 7B; and Figure 7D shows a top view of the frame wall and sensor shown in figures 7A to 7C, the sensor being integrated into said frame wall.

Detailed Description The present disclosure is described in the following by way of a number of i||ustrative examples. lt will be appreciated that these examples are provided for illustration and explanation only and are not intended to be limiting on the scope of the disclosure.

Furthermore, although the examples may be presented in the form of individual embodiments, it will be recognized that the present disclosure also covers combinations of the embodiments described herein.

Figure 1 schematically shows a top view of a battery module 1 comprising a plurality of secondary cells 2 (also referred to herein as simply 'cells 2'), having a module frame 3 containing the cells 2, and an integrated sensor 4 in the module frame 3, according to an embodiment of the present disclosure. The battery module 1 may form part of a battery pack, such as a battery pack for an electric vehicle.

The module frame 3 (also referred to herein as simply 'frame 3') may comprise two end walls 3a and 3b, and two side walls 3c and 3d. lt will be appreciated that, although the end walls 3a and 3b are referred to as being at an 'end', the end walls 3a and 3b may in fact be intermediate walls as part of a module frame 3, e.g., in a case where the battery module 1 contains a plurality of stacks of cells 2 separated by end walls 3a (and/or 3b). The same applies to the side walls 3c and 3d, which may form part of an outer structure of the module 1 and/or a battery pack in which the module 1 is integrated, or may form part of some intermediate structure thereof, such as a beam or other similar structure for separating stacks of cells 2 in the battery module 1.

The cells 2 may be aligned in a stack or column between the end walls 3a and 3b. The cells 2 may be, for example, prismatic or cylindrical, and in the illustrated example, the cells 2 are cuboidal, having two larger sides and 9 four smaller sides extending between the two larger sides. ln the illustrated example, the cells 2 are arranged such that larger sides of adjacent cells 2 are next to each other.

The cells 2 may preferably be provided with a shape that is possible to tesselate in the three-dimensional space defined by the module frame 3. Therefore, a minimum amount of wasted space may be achieved by arranging the cells 2 in a close-packed and/or tessellated way, thereby increasing the energy density of the battery module 1. ln the illustrated example, the module frame 3 defines a cuboidal space in which cuboidal cells 2 are arranged to advantageously fill substantially all of the available space. ln some examples, a minimum spacing between the cells 2 may be desired. However, even in such examples, a tessellating arrangement of cells 2 within the battery module 1 may improve the energy density thereof. ln order to monitor various characteristics of the cells 2 (or the battery module 1 as a whole), a sensor 4 may be provided. The sensor 4 may be a temperature sensor, a pressure sensor, and/or a compression sensor, or some combination thereof.

The sensor 4 may be integrated within a frame wall of the module frame 3, such as the end wall 3a. That is, the sensor 4 may be arranged in such a way in respect of the end wall 3a that at least part of the sensor 4 is enclosed thereby.

The illustrated sensor 4 comprises a sensing portion 4a for sensing characteristics of a cell 2, a connection portion 4b for connecting to a sensing circuit (not shown) and an intermediate portion 4c for connecting the sensing portion 4a to the connection portion 4b. The sensing portion 4a and the intermediate portion 4c are shown in dotted lines as these portions would not necessarily be visible from the top view shown in figure 1.

The placement of the sensor 4 at the end of the stack of cells 2 may advantageously allow for a measurement of characteristics of an end cell 2, i.e. a cell 2 at an end of the stack. ln some examples, the end cell 2 may be a most characteristic cell 2 of the stack, such that measurements thereof (of temperature, swelling, etc.) may most representatively be used to determine characteristics of the stack of cells 2 or of the battery module 1 as a whole.

The inner face of the end wall 3a shown in figure 1 is schematically shown in figure 2, with a face-on view. The end wall 3a may have a height extending between a lower face and an upper face (e.g. defined relative to the battery module's 1 p|acement in a vehicle, or otherwise defined), a width, and a thickness extending between the inner face and an outer face. lt will be appreciated that the terms 'lower', 'upper', 'inner', 'outer', etc. are merely labels provided for explanatory purposes and are not intended to place any functional limitation on the description of the end wall 3a.

As shown in figure 2, the sensing portion 4a of the sensor 4 may be arranged at the inner face and the connection portion 4b of the sensor 4b may be arranged at the upper face of the end wall 3a.

The sensing portion 4a is shown as being arranged substantially centrally at the inner face of the end wall 3a, i.e. substantially half-way along the height and the width of the end wall 3a. However, in some examples, the sensing portion 4a may be arranged at another part of the inner face.

The position at which the sensing portion 4a is arranged at the inner face may depend on a part of a cell 2 that is intended for having characteristics of said cell 2 sensed from. For example, if the sensor 4 is a temperature sensor, the sensing portion 4a may be arranged at the inner face at a position that allows for a shortest thermal path between an electrode stack in the cell 2 and the sensing portion 4a.

Similarly, if it is expected that swelling of the cell(s) 2 will cause a bulge or expansion that is largest at a center of a largest side thereof (which may be the case with some prismatic cells), then a compression sensor may be arranged at the inner face of the end wall 3a so as to correspond to said center of the largest side of the cell 2 adjacent to the end wall 3a.

Although the connection portion 4b is shown protruding above the upper face of the end wall 3a, it will appreciated that, in some examples, the connection portion 4b may be adapted or configured to form a flush profile (i.e., not protruding) with the upper face. 11 Furthermore, the connection portion 4b may be arranged centrally (as shown) or non-centrally, depending on the implementation. A sensing circuit of the battery module 1 may have particularly arranged connectors such that the connection portion 4b may be positioned and/or configured to interface therewith. ln some examples, the connection portion 4b may be arranged at a position on the upper face that minimizes an exposed amount of the sensor 4, such that the intermediate portion 4c emerges from the end wall 3a as close to a sensing circuit interface as possible.

As shown in figure 2, the sensing portion 4a (or other parts of the sensor 4) may not be tightly or snugly fitted into the end wall 3a, such that there may be a gap 5 (or cavity, opening, etc.) formed around the sensing portion 4a, which may allow for some motion of the sensing portion 4a relative to a cell 2 adjacent to the end wall 3a, according to some examples.

According to other examples, the sensing portion 4a may be configured such that there is no gap 5 formed, thereby minimizing the structural impact on the end wall 3a.

Figure 3A schematically shows an example cross-sectional view of the end wall 3a, taken along line A-A shown in figure 2. Also illustrated is a cell 2 arranged adjacent to the end wall 3a. The sensor 4 is arranged for sensing characteristics of the cell 2, which may be an end cell 2 of a stack.

The sensor 4 is shown integrated into the end wall 3a. ln the illustrated example, the sensor 4 is arranged in an opening 5 in the end wall 3a. The opening 5 may be formed during a manufacturing process that manufactures the end wall 3a itself (e.g. during an extrusion or additive manufacturing process with metal such as aluminum) or the opening 5 may be formed after the end wall 3a has been manufactured, such as by drilling, etching (e.g. using lasers or acid) or some other means. ln some examples, the end wall 3a may be formed of at least two parts, wherein at least one of the parts has a relief formed therein, such that the bringing together of the at least two parts forms the opening 5. Such an approach may advantageously allow for more complex forms for the opening 12 lt will be appreciated from at least figure 3A that, according to the presently described approach of at least partially integrating the sensor 4 into the end wall 3a, the cell 2 may be arranged closer to the end wall 3a, thus improving the energy density of the battery module 1.

Furthermore, the sensor 4 may be protected from the conditions of the internal of the battery module 1. For example, if the cell 2 experiences an overheating event, the sensor 4 (or at least the intermediate portion 4c and/or connection portion 4b) may be thermally protected and/or mechanically protected therefrom by the substance of the end wall 3a. As such, no further protective components need to be added, thereby further reducing the weight of the battery module 1 and increasing the energy density thereof. ln some examples, the sensing portion 4a may form a ﬂush profile with the inner face of the end wall 3a such that the sensing portion 4a does not excessively intrude into the cell space of the battery module 1. Furthermore, by forming a flush profile with the inner face of the end wall 3a, the sensing portion 4a may be protected by the surrounding structure of the inner face, e.g. from swelling of the cell 2, without substantially changing the structural integrity of the end wall 3a, and thereby damaging its ability to contain said swelling of the cell 2. ln other examples, the sensing portion 3a may protrude from the inner face of the end wall 3a. ln such examples, the sensing portion 3a and/or the surrounding structure (e.g. the intermediate portion 3b) may be adapted for flexibility such that a movement or expansion of the cell 2 may cause the sensing portion 3a to retreat into the opening 5.

The end wall 3a may further comprise a biasing member 6, such as a spring or some other resilient element, configured to (mechanically) bias the sensing portion 4a of the sensor 4 towards the cell 2 adjacent to the end wall 3a, as shown in figure 3B.

Accordingly, the opening 5 in the end wall 3a may be configured to allow for at least the motion of the sensor 4 against the biasing member 6, which may be caused by swelling of the cell 2, an impact to the module frame 3, or some other reason. 13 Thus, it may be possible to preserve a close proximity of the sensing portion 4a of the sensor 4 against an end cell 2 in the battery module 1, by employing a biasing member 6.

Although the different portions 4a, 4b, and 4c of the sensor 4 are shown as being separate (and, e.g., fixed together somehow), it will be appreciated that this is purely illustrative and at least some of these portions 4a, 4b, and 4c may instead each be integrally formed as part of a single structure. ln some examples, the components themselves (e.g. temperature sensor, electrical connectors, etc.) may not be suitably sized or shaped to perform the structural functions desired for the sensor 4 to thereby facilitate integration of the sensor 4 into the end wall 3a. ln such examples, the sensor 4 may further comprise a sensor housing 7 configured for aiding integration of the sensor 4 into the end wall 3a, as shown in figure 4. The housing 7 may comprise portions corresponding to portions of the sensor 4, such that a sensing portion housing 7a may house the sensing portion 4a, a connecting portion housing 7b may house the connection portion 4b, and an intermediate portion housing may house the intermediate portion 4c, if required.

As some of the portions 4a, 4b, and 4c of the sensor 4 may be subject to different stresses (e.g. mechanical, thermal, or other stresses), the respective housing(s) 7a, 7b, and/or 7c may be different. For example, the sensing portion housing 7a for a temperature sensor may be formed from a thermally conductive material.

To give a specific example, the intermediate portion 4c of the sensor may simply be a connective wire or similar, in which case the intermediate portion 4c may lack the structural integrity for insertion into the end wall 3a (if this is how integration is achieved). Such a wire may further require mechanical, thermal, or other protections so as to preserve operations of the sensor 4.

However, according to the presently disclosed arrangement, the end wall 3a itself may advantageously provide additional mechanical, thermal, 14 electrical, and/or other protections to at least the intermediate portion 4c of the sensor 4, without requiring any additional components (e.g. intermediate portion housing 7c). ln some examples, the housing 7 itself may contain the biasing member 6, or the shape and material of the housing 7 itself may be resilient so as to bias the sensing element 4a towards the cell 2. That is, the housing 7 may itself be configured as a biasing member 6.

The biasing member 6 may also prevent damage to the sensor 4 by allowing a retreat of the sensing portion 4a into the end wall 3a, such that, for example, an excessive swelling of the cell 2 does not damage the sensing portion 4a. ln some examples, the end wall 3a may be arranged between two stacks of cells 2, as shown in figure 5. ln such cases, it may be desired to sense characteristics of both end cells 2. This may be achieved using a single sensor 4, similar to that described above, and further comprising a further sensing portion 4a.

The further sensing portion 4a may be arranged at the outer face of the end wall 3a, although it will be appreciated that said face may not be 'outer' in respect of the battery module 1 as a whole. lt will be appreciated that, whilst only one sensing portion 4a per sensed cell 2 is illustrated, there may instead be multiple sensing portions 4a per sensed cell 2, such as in a central part of the cell, and at one or more side parts of the cell 2, according to some examples.

The sensing portions 4a may be biased towards their respective sensed cells 2 by one or more biasing members 6, as discussed above in relation to figure 3B. Each sensing portion 4a may be connected to a common connection portion 4b by a same or different intermediate portions 4c, and/or each sensing portion 4a may have a corresponding connection portion 4b.

By integrating the sensor 4 into the end wall 3a that is shared by multiple stacks of cells 2, the end cells 2 of said stacks may be sensed by a same sensor 4 integrated into the end wall 3a, such that a greater amount of cell space within the battery module 1 may be advantageously saved. ln some examples, the end wall 3a may be formed around the sensor 4 so as to integrate the sensor 4 within an opening 5 therein. ln other examples, the end wall 3a may be formed with an opening 5 (which may extend all the way through the end wall 3a from the inner face to the upper face), or (parts of) the opening 5 may be formed after forming the end wall 3a. ln examples where the sensor 4 is not integrated into the end wall 3a as part of a manufacturing process for the end wall 3a, the sensor 4 may be introduced into an opening 5.

Example methods for introducing the sensor 4 into an opening 5 in an end wall 3a are shown in figures 6A and 6B. ln a first example, shown in figure 6A, the opening 5 may be configured so as to extend from the inner face to the upper face, and the sensor 4 may be introduced from the upper face, with the sensing portion 4a first.

The opening 5 may be configured to allow for a guiding, channeling, or sliding of the sensor 4 therethrough. For example, the opening 5 may be provided with smooth and-or curved surfaces. Furthermore, the sensor 4 itself may be adapted for introduction into the opening 5 by being flexible (e.g. at the connections of the various portions 4a, 4b, and 4c or at the intermediate portion only 4c) and/or sized for a tight or snug fit within the opening 5.

By minimizing the opening 5 relative to the size of the sensor 4, and adapting the sensor 4 accordingly so as to take up a minimal space within the end wall 3a, the structural integrity of the end wall 3a may be better preserved.

An alternative example for introducing a sensor 4 into an opening 4 in the end wall 3a is shown in figure 6B, which may be similar to the integrated sensor 4 shown and described in relation to figure 5. ln the illustrated example, the sensing portions 4a may be biased away from each other, and thereby biased towards their respective sensed cells 2. Thus, in order to fit into the opening 5 as shown in figure 6B, the sensing portions 4a may be moved towards each other, thereby loading the biasing member 6. 16 Thereafter, when the opening 5 opens towards the inner and outer faces of the end wall 3a, the sensing portions 4a may be biased out towards the cells 2. This biasing member 6 arrangement, or a similar such arrangement, may thus provide an additional 'locking' function which holds the sensor 4 resiliently in place in the opening 5.

The manner in which the sensors 4 shown in figures 6A and 6B are adapted for introduction into an opening 5 may also allow for an easy removal from the end wall 3a, for example if maintenance or replacement is required.

Figures 7A to 7D illustrate an example embodiment of the present disclosure, wherein a sensor 4 is integrated into an extruded aluminum end wall 3a having an opening formed therein.

Figure 7A shows the inner (below) and outer (above) faces of the end wall 3a. From the outer face of the end wall 3a, a part of the intermediate portion housing 7c can be seen, which may constitute a resilient extension of the housing 7, as shown in figure 7B, acting as a biasing member similar to the function of the biasing member 6 discussed above.

From the inner face, the sensing portion 4a and the sensing portion housing 7a can be seen, wherein the sensing portion housing 7a is configured to fill the opening (not visible by virtue of having been filled) at least around the sensing portion 4a, thereby ensuring that the sensing portion 4a is reliably maintained at a substantially central part of the inner face.

From both faces, and from the top view shown in figure 7D, the connection portion 4b can be seen, housed in a connection portion housing 7b. The connection portion housing 7b may advantageously electrically insulate the connection portion 4b from the electrically conductive end wall 3a (made from aluminum). The connection portion housing 7b may be further configured to be inserted into a notch or indent (e.g. formed as an extension of the opening in the end wall 3a) so as to form a flush profile with the upper face.

The sensor 4 is shown in perspective view in figure 7B. The sensor 4 may be formed from any suitable material(s). For example, the various portions 4a, 4b, and 4c of the sensor 4 may all be housed in the housing 7. 17 The housing 7 (or at least some of the portions 7a, 7b, and 7c thereof) may be formed from plastic, silicone rubber, or some other material, and may be formed using over-molding, additive manufacturing, or some other suitable technique. lt will be appreciated that, in some examples, a further sensing portion 4a could be included in the housing 7 (e.g. in what is indicated as being part of the intermediate portion housing 7c) so as to arrange the further sensing portion 4a at the outer face of the end wall 3a.

Moreover, the resilient shape of the housing 7 as shown in figure 7B may be used as a compression sensor, such that the compression of the opposing legs of the housing 7 may used as a measure of swelling of the cells 2, for example. That is, multiple sensing portions 4a of varying types may be incorporated within the same sensor 4. ln figure 7C, a cross-sectional view of the sensing portion 4a of the sensor 4 is shown, as well as a face-on view. lt can be seen therein that the sensing portion 4a may be substantially surrounding by a sensing portion housing 7a, and may have some interfacing material 9 arranged thereon.

The sensing portion housing 7a may advantageously serve to protect and position the sensing portion 4a at a desired place, e.g. against the surface of a cell 2.

The interfacing material 9 may comprise, e.g., a thermally conductive material (in the case of a temperature sensor), a bonding material (to bond the sensing portion 4a to a cell 2), a lubricating material (to allow for ease of sliding relative to a cell 2 surface), or some other material.

As shown in figure 7D, the sensing portion 4a may protrude from the inner face, e.g., at least when a cell 2 is not pressed thereagainst. Othervvise, it can be seen that the sensor 4 is substantially confined within the dimensions of the end wall 3a. This may further be appreciated from figure 7A, showing the flush profile of the connection portion 4b with the upper surface. Thus, the placement of the sensor 4 may not interfere with the placement of other components of the battery module 1, e.g. an upper lid or casing of the module frame 3 against the upper surface. 18 lt can be seen in figure 7D that the extruded aluminum end wall 3a may comprise, as part of its extruded profile, a plurality of channels 8, which may serve as convenient openings for introduction of the sensor 4. Thus, the opening may be enhanced by creating a hole or aperture in the inner face (and outer face in some examples) to thereby form an opening from the inner face to the upper face. ln some examples, such a hole or aperture may be formed in the extruded aluminum end wall 3a as part of the extrusion process. lt will be appreciated that the implementation of a sensor adapted for integration into a frame wall, as described above in relation to figures 7A to 7D, is but one example of many which may fall within the scope of the present disclosure, and this illustrated example has been provided merely to assist in understanding particular aspects of the present disclosure.

Any reference to prior art documents or comparative examples in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Furthermore, whilst the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown and described by way of example in relation to the drawings, with a view to clearly explaining the various advantageous aspects of the present disclosure. lt should be understood, however, that the detailed description herein and the drawings attached hereto are not intended to limit the disclosure to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the following claims.

Claims

1. A frame part of a battery module frame, comprising: a frame wall having a height extending between an upper face and a lower face, and a thickness extending between an inner face and an outer face; and a sensor at least partially integrated into the frame wall, comprising: a sensing portion for sensing characteristics of a secondary cell adjacent to the frame wall; a connection portion for connecting to a sensing circuit; and an intermediate portion for connecting the sensing portion to the connection portion; wherein: the sensing portion is arranged at the inner face; the connection portion is arranged at the upper face; and the intermediate portion is enc|osed by the frame wall.

2. The frame part according to c|aim 1, wherein: the sensor comprises a sensor housing configured for aiding integration of the sensor into the frame wall.

3. The frame part according to c|aim 1 or c|aim 2, further comprising: biasing means configured to bias the sensing portion of the sensor towards the secondary cell.

4. The frame part according to c|aim 2 and c|aim 3, wherein: the biasing means is formed as part of the sensor housing.

5. The frame part according to any preceding c|aim, wherein: the sensing portion is configured to form a f|ush profile with the inner face, and/or the connection portion is configured to form a flush profile with the upper face.

6. The frame part according to any preceding claim, further comprising: an opening extending between the upper face and the inner face, configured for introduction of the sensor.

7. The frame part according to any preceding claim, wherein: the sensor comprises a further sensing portion for sensing characteristics of a secondary cell ; the further sensing portion is arranged at the outer face; and the intermediate portion is further configured for connecting the further sensing portion to the connection portion.

8. The frame part according to any preceding claim, wherein: the sensor comprises a temperature sensor, a pressure sensor, and/or 8 COmpFeSSlOn SGFISOF.

9. A battery module comprising the frame part of any of c|aims 1 to

10. The battery module according to claim 9, further comprising: a module frame having a pair of side walls, a pair of end walls, and a plurality of secondary cells aligned in a stack between the pair of end walls; wherein: the frame wall is at least one of the pair of end walls.

11. The battery module according to claim 9 or claim 10, wherein: the sensing portion is arranged to sense a characteristic of the secondary cell at a central part of said secondary cell adjacent to said at least one of the pair of end walls. to 8, comprising:

12.A method for manufacturing the frame part according to any of claimsproviding the frame wall with a cavity for receiving the sensor; and introducing the sensor into the cavity.

13. The method according to c|aim 12, wherein: the cavity comprises an opening extending between the inner face and the upper face, configured for introduction of the sensor.

14. The method according to c|aim 12 or c|aim 13, wherein: the cavity is integra||y formed with the frame wall; and/or the sensor is introduced into the cavity during a manufacturing process for manufacturing the frame wall.

15. claims 1 to A sensor adapted for integration into the frame wall according to any of