Improved insulator for a battery cell

Abstract

There is disclosed herein a battery cell (100), comprising an insulator (300) arranged between an electrode assembly (106) and a prismatic casing (102), wherein the insulator (300) comprises a recessed receiving portion (301) configured to receive an internal component (200), wherein the insulator (300) further comprises a continuous gas flow path (304) extending at least from the recessed receiving portion (301) and configured to guide gas from the recessed receiving portion (301) towards a vent (105) in the prismatic casing (102).

Description

[0001] IMPROVED INSULATOR FOR A BATTERY CELL

[0002] Technical Field

[0003] The present disclosure relates to secondary cells, and more particularly a prismatic battery cell having an improved insulator.

[0004] Background

[0005] In addressing climate change, there is an increasing demand for rechargeable batteries, e.g. to enable electrification of transportation and to supplement renewable energy. Currently, lithium-ion batteries are becoming increasingly popular. They represent a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.

[0006] As the demand for rechargeable batteries increases, more and more focus is being placed on production speed and cost. To achieve an effective production of rechargeable batteries, the design of the batteries as well as their manufacturing process can be optimized.

[0007] Summary

[0008] A battery cell stores electrical energy in an electrode assembly, which may be stacked or rolled, and referred to as an “electrode roll” or a “jelly roll”. Stored electrical energy may then be collected and transferred to the terminals of the battery cell via current collectors, which are adapted for (electrical) connection to the terminal(s) and to the electrode assembly.

[0009] During a failure event of a battery cell, gas may be generated through various chemical reactions (depending on the chemistry of the cell), and heat may also be generated, sometimes very rapidly. If a failure event is not suitably contained, it may propagate to nearby battery cells and cause their failures.

[0010] It is realized as a part of the present disclosure that a risk of propagation of failures of nearby cells is greatly increased by an explosion or rupture of a cell casing. Ruptures of a cell casing can cause an uncontrolled emission of ejecta (such as gas or charged particles) or, in some cases, parts of the cell casing (which may be made of metal such as aluminum) to come free and short-circuit nearby cells.

[0011] It is further realized as part of the present disclosure that one of the causes of a case rupture may be a build-up of gas within a cell. That is, during a failure event (such as a thermal runaway or ‘TR’ event), there is a risk for rapid generation of heat. Furthermore, internal components of the cell such as the electrode assembly may generate substantial amounts of gas. If not properly and promptly vented, this gas may cause a pressure build-up inside the casing. The presence of an insulator between the electrode assembly and a vent in the casing may be particularly problematic in this respect, as the insulator may obstruct the flow of gas from the electrode assembly to the vent.

[0012] Particularly, in prismatic cells having electrode assemblies with a substantially rectangular shape, external components (vent, terminal, electrolyte filling hole) as well as internal components (current collector, insulator) of the cell may be arranged along a longer, top side of the prismatic cell. It is realized as a part of the present disclosure that these components, and their interface with an insulator, can cause a blockage of gas flowing from the shorter sides of the cells towards the vent.

[0013] If the rapid heat generation occurs while gas is obstructed in this manner, this may lead to the battery cell exploding, destroying the battery cell, due to the rapid expansion of the gas according to thermodynamic laws. An exploding battery cell does not only risk propagating the failure to nearby battery cells, but is also a hazardous event for the surrounding environment.

[0014] Therefore, according to an aspect of the present disclosure, there is provided an improved battery cell with an insulator configured to provide insulation (which may be both physical and electrical) while preventing gas from being obstructed by providing a continuous gas flow path along the entirety of the length of the insulator, such that gas is guided along the gas flow path towards the vent or vents in the casing. In this way, gas build-up in the casing may advantageously be prevented. In particular, according to an aspect of the present disclosure, there is provided a battery cell comprising a prismatic casing housing an electrode assembly, wherein the prismatic casing comprises a vent in a first side thereof. The battery cell further comprises an insulator arranged between the electrode assembly and the first side of the prismatic casing, wherein a length of the insulator substantially extends between the vent and a second side of the prismatic casing adjacent the first side of the prismatic casing, and where a first side of the insulator faces the electrode assembly and a second side of the insulator faces the first side of the prismatic casing. The insulator comprises a recessed receiving portion configured to receive an internal component, and a continuous gas flow path extending at least from the recessed receiving portion and configured to guide gas from the recessed receiving portion towards the vent.

[0015] The insulator may be arranged to provide insulation between internal components of the cell or between internal components of the cell and the casing.

[0016] In an embodiment, the prismatic casing may have a substantially rectangular shape with two opposite longer sides and two opposite shorter sides. The first side of the prismatic casing, where the insulator is arranged, may be one of the longer sides of the casing, and more specifically the longer side arranged on a top side of the prismatic cell, where ‘top’ may be arbitrarily defined herein as the side having the vent. Thus, the second side may therefore be one of the shorter sides of the prismatic casing. In the present embodiment, wherein the prismatic cell has a substantially rectangular shape, the first side and the second side may meet at a right angle, thus being adjacent to each other.

[0017] In a further embodiment, the insulator may extend from the second side to the vent, such that the length of the insulator is the same as the distance between the second side and the vent. In another embodiment, the insulator may have a length shorter than the distance between the second side and the vent. The insulator may have a length extending from one second side of the prismatic casing to another second side of the prismatic casing, meaning that the insulator may extend between the two shorter sides of the prismatic casing. In other words, the length of the insulator may extend along a substantial length, in some examples along the entire length, of the longer side of the prismatic casing.

[0018] In an embodiment, the electrode assembly may have a substantially rectangular shape. In a preferred embodiment, the prismatic casing and the electrode assembly have corresponding shapes, such that if the electrode assembly is substantially rectangular, the prismatic casing is also substantially rectangular, and vice versa.

[0019] According to an exemplifying embodiment of the present disclosure, a thickness of the insulator extends between the electrode assembly and the first side of the casing. The insulator may thus span a space between the electrode assembly and the casing. The insulator may therefore provide structural stability to the battery cell, which may be advantageous during a crush event. The insulator may further advantageously provide insulation between the electrode assembly and the prismatic casing, preventing them from coming into (electrical) contact with each other, which could lead to an undesired event such as an electrical short circuit. The insulator may be made from a non-conductive material, such as a plastic and / or a rubber.

[0020] The recessed receiving portion of the insulator is configured to receive an internal component of the battery cell, and therefore the insulator may further provide insulation between the internal component received in the recessed receiving portion, and other internal components of the battery cell, such as the electrode assembly or the prismatic casing. Moreover, the insulator may assist in positioning the internal components within the casing.

[0021] According to an exemplifying embodiment of the present disclosure, the internal component is a current collector. The insulator may, through the recessed receiving portion, retain the current collector. By retaining the current collector, the insulator may provide electrical insulation for the current collector, while maintaining it in its intended position inside the prismatic casing. The recessed receiving portion may therefore have a shape corresponding to a shape of the current collector, such that the current collector and the recessed receiving portion form mating elements. According to an exemplifying embodiment of the present disclosure, the recessed receiving portion extends through a partial thickness of the insulator. The recessed receiving portion may extend along a portion of a length L of the insulator. By extending through a partial thickness of the insulator, the insulator may maintain its insulating capabilities while simultaneously providing an interface for receiving an internal component, for example a current collector.

[0022] According to an exemplifying embodiment of the present disclosure, the recessed receiving portion is arranged on the first side of the insulator. In the example where the internal component is a current collector, the current collector may be arranged on the electrode assembly, for example as a right- angled bracket around a corner of the electrode assembly. The recessed receiving portion may therefore be arranged on the first side of the insulator, which faces the electrode assembly, in order to receive the current collector.

[0023] Further, the continuous gas flow path of the insulator extends at least from the recessed receiving portion and guides gas from the recessed receiving portion towards the vent. The recessed receiving portion may therefore form a part of the continuous gas flow path along the insulator. The continuous gas flow path may comprise a channel extending from the recessed receiving portion towards the vent. The channel may be connected to the recessed receiving portion such that the channel and the recessed receiving portion together forms a continuous gas flow path along the insulator. Gas being generated around or close to the internal component received by the recessed receiving portion, or gas that has reached the recessed receiving portion in another way, may be advantageously prevented from getting stuck inside the recessed receiving portion through the continuous gas flow path. By providing a continuous gas flow path, the insulator may prevent the obstruction of gas, and therefore decrease the risk of gas build-up inside the battery cell.

[0024] According to an exemplifying embodiment of the present disclosure, the insulator further comprises an opening adjacent the second side of the prismatic casing, optionally formed by the recessed receiving portion, configured to guide gas from between the electrode assembly and the second side of the casing towards the vent. During a crush event or a thermal runaway, gas may be generated along all sides of the electrode assembly inside the prismatic casing. In some embodiments, the current collector may have a first portion extending along the first side of the prismatic casing, and a second portion extending along the second side of the prismatic casing, and wherein the first and second portion are connected via a right angle. In other words, the current collector may be arranged around a corner of the electrode assembly. If gas is generated along the second side of the prismatic casing, and flows upwards towards the vent in the casing, the gas may be obstructed by the current collector arranged around the corner of the electrode assembly. If a first portion of the current collector is retained by an insulator, the gas may not be able to reach the vent in an efficient way, if at all.

[0025] However, according to the present embodiment, the insulator comprises an opening adjacent the second side of the prismatic casing, which allows gas to flow through the insulator towards the vent. The opening in the insulator thereby provides a path for the gas to flow, preventing the gas from being obstructed by either the current collector or the insulator itself. Further, by arranging the opening adjacent the second side of the prismatic cell, the insulator provides a way to allow gas generated along the second side of the prismatic casing to reach the vent arranged in the first side of the prismatic casing. The insulator may therefore advantageously guide gas flow generated at different points inside the prismatic casing, towards the vent.

[0026] According to an exemplifying embodiment of the present disclosure, the insulator further comprises a second recessed receiving portion arranged on the second side of the insulator, and configured to receive a battery terminal feature. The battery terminal feature may be arranged on the first side of the prismatic cell, i.e. , on the same side of the prismatic casing as the vent. The insulator may receive both a current collector and a battery terminal feature. The second recessed receiving portion may have a shape corresponding to a shape of the battery terminal feature, such that the two parts may form a mating connection to each other. The second recessed receiving portion may ensure that the insulator is maintained in the intended position inside the casing, and together with the battery terminal feature, prevent the insulator from being displaced inside the cell during use or transportation, for example. The second recessed receiving portion and the first recessed receiving portion may at least partially overlap, in some examples.

[0027] According to an exemplifying embodiment of the present disclosure, the second recessed receiving portion comprises one or more through-holes. The battery terminal feature may extend through the thickness of the insulator via the one or more through-holes. Further, the one or more through-holes allows the battery terminal feature to be connected to the current collector. In an example, the second recessed receiving portion for a terminal is a through-hole in the first recessed receiving portion for a current collector, thereby accommodating for the connection between the current collector and the terminal.

[0028] According to an exemplifying embodiment of the present disclosure, the second recessed receiving portion is arranged in the continuous gas flow path. Gas may therefore be guided towards the vent even in the embodiment where the insulator is connected to a battery terminal feature. The second recessed receiving portion may therefore be arranged in the continuous gas flow path. The insulator prevents gas from being obstructed by internal components of the battery cell, by providing the continuous gas flow path through the insulator.

[0029] According to an exemplifying embodiment of the present disclosure, the insulator further comprises a third recessed receiving portion arranged on the first side of the insulator, and configured to receive an electrolyte filling hole feature. The electrolyte filling hole feature may be arranged on the first side of the prismatic cell, i.e. , on the same side of the prismatic casing as the vent. The insulator may receive both a current collector, a battery terminal feature, and an electrolyte filling hole feature. The third recessed receiving portion may have a shape corresponding to a shape of the electrolyte filling hole feature (e.g., round), such that the two parts may form a mating connection to each other. The third recessed receiving portion may ensure that the insulator is maintained in the intended position inside the casing, and together with the electrolyte filling hole feature, prevent the insulator from being displaced inside the cell during use or transportation, for example.

[0030] According to an exemplifying embodiment of the present disclosure, the third recessed receiving portion further comprises one or more through- holes. The electrolyte filling hole feature may extend through the thickness of the insulator via the one or more through-holes. Further, the one or more through-holes allows the electrolyte filling hole feature to be connected to the electrode assembly.

[0031] According to an exemplifying embodiment of the present disclosure, the third recessed receiving portion is arranged in the continuous gas flow path. Gas may therefore be guided towards the vent even in the embodiment where the insulator is connected to an electrolyte filling hole feature. The third recessed receiving portion may therefore form part of the continuous gas flow path. The insulator prevents gas from being obstructed by internal components of the battery cell, by providing the continuous gas flow path through the insulator.

[0032] In an example, the third recessed receiving portion is formed as a ring- shaped feature for surrounding and thereby mating with an electrolyte filling hole, where the ring-shaped feature extends across only a partial thickness of the insulator, with one or more through-holes arranged around the ring- shaped feature. In this way, gas may freely flow around the electrolyte filling hole, and may pass under the ring-shaped feature due to its partial thickness, or gas may pass up through the one or more through-holes surrounding the ring-shaped feature to thereby travel between the insulator and the casing towards the vent.

[0033] According to an exemplifying embodiment of the present disclosure, the continuous gas flow path is at least partially arranged on the second side of the insulator. Gas entering the continuous gas flow path on the first side of the insulator may therefore be guided through the thickness of the insulator, for example via the one or more through-holes, and thereby reach the second side of the insulator, facing the first side of the prismatic casing, and then exit the casing through the vent. The continuous gas flow path may comprise one or more channels along the length of the insulator. One or more channels may be arranged on the first side of the insulator, and one or more channels may be arranged on the second side of the insulator. The one or more channels may extend through a partial thickness of the insulator. Further, a channel arranged on the first side of the insulator, may form a ridge on the second side of the insulator, providing structural rigidity on the second side of the insulator, and vice versa if the channel is arranged on the second side of the insulator.

[0034] According to an exemplifying embodiment of the present disclosure, the continuous gas flow path extends along the entirety of the length of the insulator. That is, the continuous gas flow path may be formed of one or more channels together with the one or more recessed receiving portions, which all form a part of the continuous gas flow path. Thus, the continuous gas flow path extends along the entirety of the length of the insulator. The insulator may therefore prevent gas from being obstructed anywhere along the insulator. The insulator therefore provides an advantageous way to guide gas from inside the casing towards the vent, decreasing the risk of gas build-up, while providing structural stability and insulation.

[0035] It will be appreciated by those skilled in the art, and through the description of example embodiments of the present disclosure, that further advantages as well as those described above may be provided by an improved insulator arranged in a battery cell. These advantages, as well as other, may be further appreciated through a description of specific illustrated embodiments.

[0036] Brief Description of the Drawings

[0037] One or more embodiments of the present disclosure will be described, by way of example only, and with reference to the following figures, in which: Figures 1a and 1b schematically show a front view and a top view, respectively, of a prismatic cell as an example of a battery cell; Figures 2a and 2b schematically show a partial cross-sectional view of a battery cell with an insulator, during a failure event resulting in an explosion, according to a comparative example against which the present embodiments can be compared;

[0038] Figure 3 schematically shows a cross-sectional view of a battery cell having an improved insulator according to an embodiment of the present disclosure;

[0039] Figure 4 schematically shows a partial cross-sectional view of the battery cell shown in Figure 3, having generated gas;

[0040] Figure 5 schematically shows a perspective view of an insulator according to an embodiment of the present disclosure;

[0041] Figures 6a to 6c show various views of an insulator according to an example embodiment of the present disclosure.

[0042] Detailed Description

[0043] The present disclosure is described in the following by way of a number of illustrative examples. It 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 present disclosure. Instead, the scope of the present disclosure is defined by the appended claims.

[0044] Furthermore, although embodiments may be presented individually for the sake of focused discussion of particular features, it will be recognized that the present disclosure also encompasses combinations of the embodiments described herein.

[0045] Figures 1a and 1b schematically show a battery cell 100, also referred to hereinafter as “cell 100”, having a prismatic form factor. The cell 100 may have a substantially cuboidal shape, thereby having a rectangular profile, as shown in fig. 1a.

[0046] The cell 100 may comprise a casing 102, which may determine the general form factor of the cell 100 and may be configured (e.g., in its dimensions) for installation into a larger battery module, battery pack, or other external shocks or impacts, for example being made of metal such as aluminum, or made of a high-density plastic.

[0047] The casing 102 may be formed from a plurality of sides joined together or may be formed of substantially one or two pieces, e.g., by extrusion, additive manufacturing (AM), or some other manufacturing technique. According to an example, the casing 102 may comprise a height (extending vertically as shown in figure 1a), a width (extending horizontally as shown in figure 1a and 1 b), and a thickness (as shown in figure 1 b).

[0048] The prismatic form factor for the cell 100, as defined substantially by the casing 102, may comprise two larger faces 102b, 102f spaced apart by a relatively small distance in the thickness direction, and a plurality of comparatively smaller faces 102a, 102c, 102d, 102e bridging between the two larger faces 102b, 102f . The casing 102 may be formed by providing an open cuboidal shape with a lid. For example, the lid may form the upper face 102a of the casing 102 (shown in more detail in figure 1 b).

[0049] Internal components of the cell 100 may be introduced into the casing 102 and then a lid 102a may be provided thereover and sealed in place to thereby contain the internal components. The lid 102a may be attached in a substantially watertight fashion so as to contain liquid electrolyte in the cell 100, for example. The lid 102a may be provided with a failure vent 105 (or simply ‘vent 105’), an injection port 107 for injecting electrolyte, and / or other features, the details of which are outside the scope of the present disclosure.

[0050] In the illustrated example, provided on the casing 102 of the cell, and extending therethrough to an internal space of the cell 100, are a pair of terminals 104. One of the terminals 104 may be a negative electrode (e.g., an anode) and the other may be a positive electrode (e.g., a cathode). The terminals 104 may be riveted through the casing 102, e.g., through the lid 102a thereof, and provided with a gasket therearound to improve the watertight seal that the casing 102 may preferably provide. The terminals 104 may be made of any suitable conductive material, although the particular manufacture and installation of the terminals 104 is outside the scope of the present disclosure. Both of the terminals 104 are shown installed at an upper face 102a of the casing 102 of the cell 100. However, it will be appreciated that either of the terminals 104 may instead be provided at any location around the casing 102 of the cell 100.

[0051] Figures 2a and 2b schematically show a partial cross-sectional view of a battery cell 100 with spacing elements 110a, 110b, during a failure event resulting in an explosion, according to a comparative example against which the present embodiments can be compared. 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.

[0052] The cross-section shown in figures 2a and 2b correspond to the portion 100a indicated by the dotted box in figure 1a and the cross-section is taken along the line A-A as shown in figure 1 b.

[0053] According to this comparative example, the spacing elements 110a, 110b may be arranged to provide spacing between internal components of the battery cell 100. In the illustrated example, one spacing element 110a is arranged between upper face 102a (as illustrated) of the casing 102 (which may be the lid) and an electrode assembly 106, and another spacing element 110b is arranged between side face 102e (as illustrated) of the casing 102 and the electrode assembly 106 so as to provide appropriate spacing therebetween.

[0054] In this example, the terminal 104 extends through the spacing element 110a and connects to a current collector 200 so as to form a current path between the terminal 104 and the electrode assembly 106. By maintaining an appropriate spacing between the terminal 104, the casing 102, the electrode assembly 106, and the current collector 200, these components may be prevented from being displaced or coming into contact with each other, which may cause a short-circuit.

[0055] During normal operation or during a failure (e.g., in the initial stages thereof), the electrode assembly 106 may generate gas as a result of being heated, or one or more chemical reaction, the specifics of which are outside the scope of the present disclosure. As shown in figure 2a, this gas may collect in the cell 100 and may cause a build-up P. In some cases, this buildup P may have an increased pressure relative to the ambient operational pressure of the cell 100. In the illustrated example, the terminal 104, vent 105 and electrolyte filling hole 107 (not seen in figure 2a) are arranged in the upper face 102a of the casing 102, along the longer, top side of the prismatic cell 100.

[0056] According to this comparative example, the spacing element 110a blocks (or otherwise obstructs) a passage of generated gas and therefore contributes to the build-up P along the short side of the cell 100 as illustrated. For example, for gas from build-up P to escape the cell 100, the gas has to flow past the current collector 200 and around the sides of the insulator 110a along the faces 102b, 102f of the cell 100. The current collector 200 may be arranged around a corner of the electrode assembly 106 and therefore also contribute to the build-up P along the short side of the cell 100. Thus, when the cell 100 accelerates in its heating due to, e.g., a TR event, the build-up P of gas is (super-)heated and therefore it will be appreciated that the gas rapidly expands, according to thermodynamic principles. As shown in figure 2b, this rapid expansion can lead to an explosion E of the cell 100.

[0057] During the explosion E of the cell 100, the casing 102 may be ruptured and / or fragmented, causing pieces thereof to be propelled from the explosion E. The casing 102 may be made of metal such as aluminum and, thus, is a piece of the casing 102 were to contact across the terminals of a nearby cell, a short-circuit of said cell could be caused, which could trigger the subsequent failure of said cell and thus propagate the failure event.

[0058] Therefore, aspects of the present disclosure are directed toward preventing a build-up of gas within a cell, is it is realized as a part of the present disclosure that this can reduce damage to a cell during a failure event and the risk of the failure event propagating to nearby cells.

[0059] Figure 3 schematically shows a cross-sectional view of a battery cell 100 comprising two improved insulators 300 according to an embodiment of the present disclosure, wherein the insulators 300 are configured to guide gas flow from inside the casing 102 towards a vent 105 in the casing 102.

[0060] Like-numbered components of the cell 100 may be the same as those described above in relation to figures 1 , 2a and 2b, or at least substantially similar in their function so as not to warrant further discussion.

[0061] Figure 3 shows two insulators 300, each connected to a terminal 104 in the upper face 102a of the casing 102. Each insulator 300 has a length extending between a vent 105 and a second side 102d, 102e of the casing 102. Each insulator 300 may span a space between the electrode assembly 106 and the upper face 102a of the casing 102, as illustrated.

[0062] In another example (not shown), the two insulators 300 may be one insulator 300, extending from one second side 102d, to the other second side 102e of the casing 102. The insulator 300 may therefore be connected to both terminals 104 in the upper face 102a of the casing 102. The insulator 300 in the present example may further be connected to the vents 105, and span a space between the electrode assembly 106 and the upper face 102a of the casing 102.

[0063] Figure 4 shows the battery cell 100 of figure 3, having the improved insulator 300, showing a gas flow G through the cell 100. As for figures 2a and 2b, figure 4 corresponds to the portion 100a indicated by the dotted box in figure 1a and the cross-section is taken along the line A-A as shown in figure 1 b.

[0064] The insulator 300 contained in the example embodiment shown in figures 3 and 4 is arranged in a fluid path between the electrode assembly 106 and the vent 105, and is configured to guide gas flow G by comprising a continuous gas flow path along the entirety of the length L of the insulator 300. The continuous gas flow path may comprise one or more through-holes, one or more channels, and / or one or more recessed portions, for example. The right side of the electrode assembly 106 (as illustrated) may generate gas G which is incident upon the insulator 300, shown in a fluid path between the electrode assembly 106 and the vent 105. In particular, in this illustrated example, a fluid path is present along the right side (as illustrated) of the electrode assembly (e.g., around the current collector 200) and along the upper side of the cell 100, i.e., bounded by the upper face 102a. The insulator 300 is then arranged in this fluid path such that the flow of gas G can be guided, e.g., steered, around the corner of the electrode assembly 106 and toward the vent 105. it will be appreciated that a fluid path also exists between the upper side (as illustrated) of the electrode assembly 106 and the vent 105. If the insulator 300 were arranged in this fluid path, gas G may be permitted therethrough and out of the vent 105 through the provision of the continuous gas flow path.

[0065] The illustrated insulator 300 also guides gas flow G around the internal components of the terminal 104. The insulator 300 may be further configured to mate or otherwise engage with the current collector 200 and / or electrode assembly, and / or the electrolyte filling hole 107, depending on the implementation.

[0066] Figure 5 schematically shows a perspective view of an improved insulator 300 according to an example embodiment of the present disclosure.

[0067] The insulator 300 has a first side 302a, which, when arranged in the casing 102, faces the electrode assembly 106, and a second side 302b which faces the upper face 102a of the casing 102. According to an example, the insulator 300 may comprise a height (extending vertically as shown in figure 6a), a length L (extending horizontally as shown in figure 6a), and a thickness t. The insulator 300 has a substantially rectangular shape, comprising the two sides, or ‘faces’ 302a, 302b spaced apart by a relatively small distance in the thickness direction, and a plurality of comparatively smaller faces 302c, 302d, 302e, 302f bridging between the two sides 302a, 302b.

[0068] On the first side 302a of the insulator 300 (as shown in figure 5), there is a recessed receiving portion 301 . The recessed receiving portion 301 may receive an internal component of the cell 100, e.g., a current collector 200. The shape of the recessed receiving portion 301 may therefore be adapted to correspond to a shape of the internal component it is intended to receive. The recessed receiving portion 301 extends from the shorter side 302e of the insulator 300 and along a partial length of the insulator 300. The recessed receiving portion 301 is formed by a recess in the first side 302a of the insulator 300, the recess having a ‘depth’ extending through a partial thickness of the insulator 300.

[0069] The recessed receiving portion 301 may guide gas (not visible) around the current collector 200 received therein, and towards a continuous gas flow path 304 formed in the insulator 300. In an example, gas may enter the recessed receiving portion 301 through the opening formed in the face 302e of the insulator 300 as a result of the recessed receiving portion 301 comprising a recess extending through the partial thickness of the insulator 300. This opening allows gas to flow into the insulator 300 and around the current collector 200 rather than around an outside of the insulator 300, facilitating the venting of the cell 100.

[0070] The continuous gas flow path 304 extends from the recessed receiving portion 301 towards the vent, through the entirety of the length of the insulator 300. The continuous gas flow path 304 is formed as a channel in the first side 302a of the insulator 300. The continuous gas flow path 304 has a ‘depth’ extending through a partial thickness of the insulator. In an example, the depth of the continuous gas flow path 304 and the depth of the recessed receiving portion 301 are the same. The continuous gas flow path 304 may extend in a substantially horizontal direction across the first side 302a (as illustrated).

[0071] The insulator 300 comprises a third recessed receiving portion 306 arranged on the first side 302a thereon. The third recessed receiving portion 306 is configured to receive an electrolyte filling hole feature (not visible). The third recessed receiving portion 306 may comprise one or more through-holes 306a, 306b, 306c, 306d. The recessed receiving portion 306 may further comprise a receiving feature 307, configured to engage with the electrolyte filling hole feature. The receiving feature 307 may, as illustrated, have a round shape, preferably corresponding to a shape of the electrolyte filling hole feature, and extend through a partial thickness of the insulator 300. The receiving feature 307 may therefore be recessed from the first side 302a, and encircled by the through-holes 306a, 306b, 306c, 306d. The third recessed receiving portion 306 may therefore be partially a recessed portion, formed by the receiving feature 307, and partially a through-hole, formed by through- holes 306a, 306b, 306c, 306d. The receiving feature 307 may provide structural stability to the insulator 300 while the through-holes 306a, 306b, 306c, 306d may provide a path for gas to flow, thereby forming a part of the continuous gas flow path 304. The receiving feature 307 may further ensure that the insulator 300 is maintained in an intended position in the casing 102, preventing the insulator 300 from moving around inside the casing 102. The third recessed receiving portion 306 is arranged along the continuous gas flow path 304 and, as illustrated, may ‘split’ the channel comprised by the continuous gas flow path 304 into two channels, one on each side of the third recessed receiving portion 306. The third recessed receiving portion 306 may therefore form an integral part of the continuous gas flow path 304.

[0072] The third recessed receiving portion 306 comprises two structural elements 307a, 307b arranged on two sides of the third recessed receiving portion 306. The structural elements 307a, 307b, may as illustrated, be arranged on a top side and a bottom side of the third recessed receiving portion 306, respectively. The structural elements 307a, 307b may engage with a feature (not visible) on the lid 102a, e.g., for positioning during installation, and provide structural stability.

[0073] The insulator 300 comprises two engagement features 308a, 308b arranged in the left-hand side 302e thereof, as illustrated. The two engagement features 308a, 308b may engage a feature on the first side 102a of the casing 102, for positioning during installation, for example.

[0074] Gas flowing along the continuous gas flow channel 304 and reaching the electrolyte filling hole received in the third recessed receiving portion 306, may flow around the electrolyte filling hole feature via the through-holes 306a, 306b, 306c, 306d, and either continue to flow through the continuous gas flow path 304 on the opposite side of the third recessed receiving portion 306, or flow towards the second side 302b of the insulator 300, and further towards the vent along said second side 302b.

[0075] Figure 6a shows a top view of the insulator 300 according to an example embodiment of the present disclosure. The first side 302a is shown facing upwards, which is the side facing the electrode assembly 106 when the insulator 300 is installed in the cell 100. The insulator 300 has a length L, and it is clearly seen that the continuous gas flow path 304 extends along the entirety of the length L of the insulator 300. The continuous gas flow path 304 may be formed by the first recessed receiving portion 301 , the third recessed receiving portion 306, and the channel connecting the first 301 , and third 306 recessed receiving portions, respectively, for example. The insulator 300 has a second recessed receiving portion 305, arranged in the first recessed receiving portion 301 . The second recessed receiving portion 305 is configured to receive a terminal feature 104 of the cell 100. In an example, as illustrated, the second recessed receiving portion 305 is a through-hole. The through-hole 305 has a substantially rectangular shape, preferably corresponding to a shape of the terminal feature 104. Since the through-hole 305 is arranged in the first recessed receiving portion 301 , gas flowing from the side 302e and reaching the terminal feature 104, may flow around the terminal feature 104 in the first recessed receiving portion 301. The first recessed receiving portion 301 prevents the gas from being obstructed by the terminal feature 104 being installed in the insulator 300. The engagement between the second recessed receiving portion 305 and the terminal feature 104 prevents the insulator 300 from moving around inside the casing 102.

[0076] On the right-hand side 302f of the insulator 300, as illustrated, there is an opening 309. The opening 309 forms a part of the continuous gas flow channel 304, and allows gas to flow out from the insulator 300 towards the vent. The opening 309 may comprise an engagement feature 309a, for engaging with a part (not visible) on the lid 102a, for positioning during installation, for example.

[0077] Figures 6b and 6c illustrate side views of the insulator 300 according to exemplifying embodiments of the present disclosure. Figure 6b shows the insulator viewed from side 302e, and figure 6c shows the insulator viewed from a side 302f. The insulator 300 has a thickness t (seen in figure 6b), and the first recessed receiving portion 301 has a thickness t1 (seen in figure 6c) which is smaller than the thickness t of the insulator 300. The continuous gas flow path 304 protrudes from the second side 302b of the insulator 300, thereby providing structural stability to the insulator 300.

[0078] Aspects of the present disclosure may be better understood through appreciation of the following numbered clauses:

[0079] 1 . A battery cell (100), comprising: a prismatic casing (102) housing an electrode assembly (106), wherein the prismatic casing (102) comprises a vent (105) in a first side (102a) of the prismatic casing (102); an insulator (300) arranged between the electrode assembly (106) and the first side (102a) of the prismatic casing (102), wherein a length (L) of the insulator (300) substantially extends between the vent (105) and a second side (102d) of the prismatic casing (102) adjacent the first side (102a) of the prismatic casing (102); wherein a first side (302a) of the insulator (300) faces the electrode assembly (106) and a second side (302b) of the insulator (300) faces the first side (102a) of the prismatic casing (102); wherein the insulator (300) comprises a recessed receiving portion (301 ) configured to receive an internal component (200); and wherein the insulator (300) further comprises a continuous gas flow path (304) extending at least from the recessed receiving portion (301 ) and configured to guide gas from the recessed receiving portion (301 ) towards the vent (105).

[0080] 2. Battery cell (100) according to clause 1 , wherein the internal component is a current collector (200). 3. Battery cell (100) according to clause 1 or clause 2, wherein the recessed receiving portion (301 ) is arranged on the first side (302a) of the insulator (300).

[0081] 4. Battery cell (100) according to any preceding clause, wherein the insulator (300) further comprises an opening (301 ) adjacent the second side (102d) of the prismatic casing (102), optionally formed by the recessed receiving portion (301 ), configured to guide gas from between the electrode assembly (106) and the second side (102d) of the casing towards the vent (105).

[0082] 5. Battery cell (100) according to any preceding clause, wherein the insulator (300) further comprises a second recessed receiving portion (305) arranged on the second side (302b) of the insulator (300), and configured to receive a battery terminal feature (104).

[0083] 6. Battery cell (100) according to clause 5, wherein the second recessed receiving portion (305) comprises one or more through-holes.

[0084] 7. Battery cell (100) according to clause 5 or 6, wherein the second recessed receiving portion (305) is arranged in the continuous gas flow path (304).

[0085] 8. Battery cell (100) according to any one of the preceding clause, wherein the insulator (300) further comprises a third recessed receiving portion (306) arranged on the first side (302a) of the insulator (300), and configured to receive an electrolyte filling hole feature.

[0086] 9. Battery cell (100) according to clause 8, wherein the third recessed receiving portion (306) further comprises one or more through-holes (306a, 306b, 306c, 306d). 10. Battery cell (100) according to clause 8 or 9, wherein the third recessed receiving portion (306) is arranged in the continuous gas flow path (304).

[0087] 11 . Battery cell (100) according to any one of the preceding clause, wherein a thickness (t) of the insulator (300) extends between the electrode assembly (106) and the first side of the casing (102a).

[0088] 12. Battery cell (100) according to any one of the preceding clauses, wherein the recessed receiving portion (301 ) extends through a partial thickness (t1 ) of the insulator (300).

[0089] 13. Battery cell (100) according to any one of the preceding clauses, wherein the continuous gas flow path (304) is at least partially arranged on the second side (302b) of the insulator (300).

[0090] 14. Battery cell (100) according to any one of the preceding clauses, wherein the continuous gas flow path (304) extends along the entirety of the length (L) of the insulator (300).

[0091] 15. An insulator (300) adapted for use in a battery cell (100) according to any preceding clause.

[0092] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown and described above by way of example in relation to the drawings, with a view to clearly explaining the various advantageous aspects of the present disclosure. It 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

C L A I M S1 . A battery cell (100), comprising: a prismatic casing (102) housing an electrode assembly (106), wherein the prismatic casing (102) comprises a vent (105) in a first side (102a) of the prismatic casing (102); an insulator (300) arranged between the electrode assembly (106) and the first side (102a) of the prismatic casing (102), wherein a length (L) of the insulator (300) substantially extends between the vent (105) and a second side (102d) of the prismatic casing (102) adjacent the first side (102a) of the prismatic casing (102); wherein a first side (302a) of the insulator (300) faces the electrode assembly (106) and a second side (302b) of the insulator (300) faces the first side (102a) of the prismatic casing (102); wherein the insulator (300) comprises a recessed receiving portion (301 ) configured to receive an internal component (200); and wherein the insulator (300) further comprises a continuous gas flow path (304) extending at least from the recessed receiving portion (301 ) and configured to guide gas from the recessed receiving portion (301 ) towards the vent (105).

2. Battery cell (100) according to claim 1 , wherein the recessed receiving portion (301 ) is arranged on the first side (302a) of the insulator (300).

3. Battery cell (100) according to any preceding claim, wherein the insulator (300) further comprises an opening (301 ) adjacent the second side (102d) of the prismatic casing (102), optionally formed by the recessed receiving portion (301 ), configured to guide gas from between the electrode assembly (106) and the second side (102d) of the casing towards the vent (105).

4. Battery cell (100) according to any preceding claim, wherein the insulator (300) further comprises a second recessed receiving portion (305) arranged on the second side (302b) of the insulator (300), and configured to receive a battery terminal feature (104).

5. Battery cell (100) according to any one of the preceding claims, wherein the insulator (300) further comprises a third recessed receiving portion (306) arranged on the first side (302a) of the insulator (300), and configured to receive an electrolyte filling hole feature.

6. Battery cell (100) according to any one of the preceding claims, wherein a thickness (t) of the insulator (300) extends between the electrode assembly (106) and the first side of the casing (102a).

7. Battery cell (100) according to any one of the preceding claims, wherein the recessed receiving portion (301 ) extends through a partial thickness (t1 ) of the insulator (300).

8. Battery cell (100) according to any one of the preceding claims, wherein the continuous gas flow path (304) is at least partially arranged on the second side (302b) of the insulator (300).

9. Battery cell (100) according to any one of the preceding claims, wherein the continuous gas flow path (304) extends along the entirety of the length (L) of the insulator (300).

10. An insulator (300) adapted for use in a battery cell (100) according to any preceding claim.

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