Description:FIELD
The present disclosure relates to the field of to a battery safety technology and more particularly, to a vent mechanism for pressure relief in an electrochemical cell.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Rechargeable lithium-ion cells, available in various configurations such as cylindrical, prismatic, and pouch-type, are widely used in high-energy applications including electric vehicles (EVs), power tools, consumer electronics, and grid-scale energy storage systems. These cells are typically enclosed in sealed casings to maintain internal pressure and isolate the active materials from external environments. However, under abnormal operating conditions such as overcharging, thermal runaway, or internal short-circuiting, gas generation within the cell can lead to a rapid increase in internal pressure or pressure build-up.
To mitigate the risks associated with pressure build-up, lithium-ion cells are provided with a vent mechanism (or a venting assembly), also referred to as a safety vent, which serves as a pressure-relief feature. The primary function of the vent is to allow the safe expulsion of gases when internal pressure exceeds a predefined threshold, thereby preventing structural rupture, cell explosion, or thermal propagation to adjacent cells or modules.
In conventional cylindrical cell architectures such as the widely adopted 4680 or 4695 battery configurations, the vent mechanism is typically configured on either the top lid or bottom lid of the cell. These vents are often implemented using rupturable membranes that include pressure-activated groove region, configured to deform or fracture under excess internal pressure.

While such configurations offer basic pressure relief, they suffer from several drawbacks. First, the geometry of the groove, which is commonly linear or circular, may not consistently direct crack initiation or propagation. As a result, venting may be delayed or incomplete under rapid pressure build-up, such as during thermal runaway events. Second, due to the non-optimized stress distribution in the groove area, conventional vents may require higher activation pressures (often ≥20 bar), thereby reducing the safety margin, especially during high-rate charging, overcurrent conditions, or manufacturing defects.
Further, the absence of strain localization often results in unpredictable tear or rupture paths. Cracks may propagate radially or non-uniformly across the membrane, leading to fragmentation, debris ejection, or partial venting, which fails to fully relieve internal pressure. In some cases, the entire membrane may detach upon activation, posing risks such as internal shorting, blockage of gas escape pathways, or contamination of neighbouring battery modules.
Thus, there is a need for a venting assembly for an electrochemical cell that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a venting assembly for a cylindrical electrochemical cell that ensures controlled, and safe release of internal gas pressure under abnormal operating conditions such as thermal runaway, overcharging, or internal short circuit.
Another object of the disclosure is to provide a venting assembly that facilitates directional and controlled rupture of the vent membrane.
Yet another object of the disclosure is to provide a venting assembly that facilitates efficient and scalable manufacturing.
Still another object of the disclosure is to provide a venting assembly that minimizes risk related to membrane detachment and debris generation during venting.
Yet another object of the disclosure is to provide a venting assembly that facilitates localized strain concentration and predictable rupture initiation.
Still another object of the disclosure is to provide a venting assembly that offers cost-effective and scalable manufacturing suitable for large-volume production of lithium-ion battery cells.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a venting assembly for an electrochemical cell, wherein the electrochemical cell comprises a jelly roll electrode structure housed within a cylindrical casing. The venting assembly comprises at least one lid, configured to seal at least one axial end of the cylindrical casing; a vent membrane, configured to be fitted on an operative surface of the lid, the vent membrane configured to vent gas under abnormal conditions; and a groove profile, configured on an operative surface of the vent membrane, the groove profile configured to concentrate mechanical strain.
In an embodiment, the lid includes a top lid (not shown) and a bottom lid, configured to seal the axial ends of the cylindrical casing respectively, wherein the vent membrane is fitted to the lower operative surface of the bottom lid by means of welding, preferably by means of a laser welding.
Further, the groove profile comprises a spline-curve path extending across at least a portion of the vent membrane, the spline-curve path having at least one curvature inflection zone configured to enhance strain localization and generate a directional rupture of the vent membrane in response to pressure build-up within the cell upon exceeding a predetermined threshold, wherein the directional rupture is configured to release internal gas in a controlled manner without full detachment of the vent membrane.
In an embodiment, the spline-curve path is extending continuously between a first terminal point and a second terminal point on the vent membrane to form the directional rupture path during pressure build-up within the cell.
In an embodiment, the vent membrane comprises a first thickness in a region surrounding the groove profile and a second, reduced thickness at the groove profile to facilitate localized rupture around the defined path under internal gas pressure.
In an embodiment, the first thickness is in the range of 0.45 mm to 0.55mm in a region surrounding the groove profile to facilitate welding and the second thickness is in the range of 0.15 mm to 0.25mm at the groove profile to facilitate localized rupture.
In an embodiment, the groove profile is formed by the stamping process. The groove profile is configured to cause partial rupture of the vent membrane without full detachment such that a portion of the vent membrane remains affixed to the bottom lid after venting to facilitate controlled release of gas.
In an embodiment, the venting assembly further includes a polymeric vent cap, configured to be disposed on the vent membrane.
In an embodiment, the groove profile is configured to rupture upon exceeding the predetermined threshold pressure in the range of 14±4 bar.
In an embodiment, the vent membrane is preferably selected from aluminium or aluminium alloys.
In an embodiment, the venting assembly includes at least one current collector plate, wherein the lid is configured to enclose the current collector plate with the vent membrane in the cylindrical casing.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A venting assembly, of the present disclosure, for an electrochemical cell will now be described with the help of the accompanying drawing, in which:
FIG. 1 is a schematic exploded view of a cylindrical electrochemical cell incorporating the venting assembly, the jelly roll electrode structure, cylindrical casing, bottom lid, current collector plate, vent hole and vent membrane in their assembled positions according to an embodiment of the present disclosure.
FIG. 2 is a schematic cross-sectional view of a cylindrical electrochemical cell incorporating the venting assembly, illustrating the jelly roll, casing, bottom lid, and vent membrane in their assembled positions, according to the present disclosure.
FIG. 3 is an enlarged view of the venting assembly portion of the cell, illustrating the bottom lid, the welded vent membrane, and the groove profile formed on the top surface of the vent membrane.
FIG. 4A is a top view of the bottom lid with attached vent membrane according to the present disclosure.
FIG. 4B is a top view of the vent membrane showing the spline-curve groove path according to the present disclosure.
FIG. 4C is a sectional view of the vent membrane showing the groove of the spline-curve, illustrating the differential thicknesses of the vent membrane, indicating the groove profile with reduced thickness and the surrounding thicker region suitable for welding.
FIG. 5A is a top-view illustrating the high strain zone around the curvature inflection zone of the venting membrane under internal pressure, in accordance with the present disclosure.
FIG. 5B is a sectional-view illustrating the high strain zone around the curvature inflection zone of figure 5A under internal pressure, in accordance with the present disclosure.
FIG. 6A-6B is a simulation plot illustrating equivalent stress distribution along the spline-curve groove under internal pressure build-up, showing localized stress concentration at the curvature inflection zone.
LIST OF REFERENCE NUMERALS
500 Electrochemical cell
100 Cylindrical casing
102 Jelly roll electrode structure
104 Bottom lid
106 Current collector plate
107 Venting assembly
108 Vent membrane
110A Groove profile
110B Spline-curve path
112 Vent hole
114 Vent cap
116 Weld interface region
118 Curvature inflection zone (of groove)
120 Directional rupture path
122 Strain zone
DETAILED DESCRIPTION
The present disclosure relates to a venting assembly (107) for a cylindrical electrochemical cell (500), more particularly a lithium-ion cell (500) employing a jelly roll-type electrode structure (102). The present disclosure focusses to address the challenges of internal pressure management within sealed cells under abnormal operating conditions such as thermal runaway, overcharging, or internal short-circuit events. Specifically, the present disclosure enables controlled, directional, and partial rupture of a vent membrane (108) to facilitate safe gas release, while maintaining the mechanical integrity of the cell assembly.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an”, and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including”, and “having”, are open ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be constructed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being “mounted on”, “engaged to”, “connected to”, or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
Embodiments of the present disclosure will now be described with reference to the accompanying drawing.
Cylindrical lithium-ion cells typically consist of a spirally wound electrode assembly, commonly referred to as a jelly roll, enclosed within a metallic cylindrical casing (100). The jelly roll includes alternating layers of a positive electrode, a separator, and a negative electrode, soaked in an electrolyte. The casing (100) is sealed at both axial ends by lids, such as a top lid (not shown) and a bottom lid (104, forming a hermetically sealed housing.
During operation, certain fault conditions may lead to electrolyte decomposition and gas generation, causing internal pressure to rise sharply. Without a reliable pressure-relief mechanism, the cell (500) may experience mechanical swelling, structural rupture, or even explosion. To overcome such risks, the present disclosure envisages a venting assembly (107) for the electrochemical cell.
Different embodiment of the present disclosure is explained with respect to figure 1 to figure 6A-6B.
In accordance with the figure 1 of the present disclosure, to mitigate the aforementioned risks, the venting assembly (107) is structurally and functionally integrated with the lids of the cell (500). In a preferred embodiment, the venting assembly (107) is fitted to the bottom lid (104) of the cylindrical casing (100). However, the venting assembly (107) may be mounted on either on the top lid (not shown) also, or on bottom lid (104). The venting assembly (107) comprises a vent membrane (108) and a groove profile (110A) configured on the operative top surface of the vent membrane (108). The vent membrane (108) is configured to be fitted and welded to the operative lower surface of the bottom lid (104) to form a weld interface region (116), such that it provides a barrier against internal pressure under normal conditions and enables pressure release under predefined failure conditions. FIG. 2 is a schematic cross-sectional view of a cylindrical electrochemical cell (500) incorporating the venting assembly (107), illustrating the jelly roll, the casing (100), bottom lid (104), and the vent membrane (108) in their assembled positions, according to the present disclosure.
In an embodiment, the vent membrane (108) is made from a group of ductile metallic material, preferably aluminium or aluminium alloy.
In an embodiment, the operative section of the vent membrane (108) is joined to the bottom lid (104) of the cylindrical casing (100) by welding, preferably by means of a laser welding, which offers minimal thermal distortion and high precision. The weld interface region (116) ensures mechanical stability under pressure, where necessary, and gas-tight sealing during operation.
In accordance with figure 3, the groove profile (110A) formed on the operative top surface of the vent membrane (108) is an essential feature of the present disclosure. Unlike conventional circular or linear vent grooves, the groove profile (110A) in the present disclosure is defined by a spline-curve path (110B). The spline-curve path (110B) includes at least one curvature inflection zone (118), configured to localize and concentrate mechanical strain zone (122) during pressure build-up. The curve geometry around the curvature inflection zone (118) and depth are selected such that the groove profile (110A) exhibits a stress concentration region compared to the surrounding vent membrane (108) area, thereby initiating at least one directional rupture (120) path precisely along the spline-curve path (110B) when pressure within the cell (500) exceeds a defined threshold limit.
In one embodiment, the spline-curve path (110B) extends continuously between a first terminal point and a second terminal point on the surface of the vent membrane (108). This continuity ensures that the rupture, once initiated, propagates directionally along the groove, avoiding radial or uncontrolled tearing. The use of curvature inflection zones (118) in the spline-curve path (110B) of the groove facilitate in distributing the mechanical strain energy evenly and uniformly, which further enhances the predictability of crack initiation and propagation. FIG. 4A is a top view of the bottom lid (104) with the vent membrane (108) affixed thereto, illustrating the relative positioning and integration of the venting assembly (107). FIG. 4B is a top view of the vent membrane (108) illustrating the spline-curve groove profile (110B) formed on its surface, in accordance with the present disclosure..
In another embodiment, the groove profile (110A) is defined by an elliptical-shaped curve without forming a closed loop. The formation of a closed loop may allow complete tearing of the vent membrane (108), which may affect the structural retention of the membrane post-rupture and lead to full detachment of the torn vent membrane (108) segment. Such full detachment may result in the release of metal fragments, which may cause potential electrical short circuits, or obstruction of the gas flow pathway, thereby compromising the safety and operational reliability of the electrochemical cell (500). In contrast, the use of an open elliptical or spline-curve path (110B) promotes partial rupture, to facilitate the torn segment of the vent membrane (108) to remain mechanically affixed to the vent membrane (108) and facilitating controlled pressure relief without fragment ejection.
Further, to support the above functionality of directional rupture (120), the vent membrane (108) is fabricated with varying thickness across different regions. A first thickness is provided in the region surrounding the groove profile (110A), typically in the range of 0.45 mm to 0.60 mm, to ensure mechanical support and enable high-integrity welding with the closure element. And, A second, reduced thickness is provided specifically in the groove profile (110A), in the range of 0.15 mm to 0.25 mm, to facilitate localized rupture under mechanical strain or stress concentration. The variation in thickness thus, enables precise control over the burst characteristics of the vent membrane (108). FIG. 4C is a sectional view of the vent membrane (108) showing the groove of the spline-curve, illustrating the differential thicknesses of the vent membrane (108), indicating the groove profile (110A) with reduced thickness and the surrounding thicker region suitable for welding.
In a preferred embodiment, the first thickness is provided in the region surrounding the groove profile (110A) is 0.5mm to facilitate the welding of the vent membrane (108) on the bottom lid (104), whereas second, reduced thickness is provided specifically in the spline-curve path (110B) of groove profile (110A) is 0.2mm to facilitate stress concentration and directional rupture (120).
In a preferred embodiment, the groove profile (110A) is formed using a stamping process, which is compatible with high-speed automated cell (500) manufacturing environments. Stamping allows high dimensional accuracy, repeatability, and material efficiency, making the process well-suited for large-scale production of lithium-ion cells.
Advantageously, the groove profile (110A) configured on the venting assembly (107) of the present disclosure offers partial rupture of the vent membrane (108). Upon activation, the vent membrane (108) tears along the spline-curve path (110B), thus creating an outlet for pressure release or venting gas, while a portion of the membrane remains mechanically affixed to the vent membrane (108). This prevents the fragments of the vent membrane (108) from detaching and causing potential electrical short circuits, mechanical damage, or debris contamination. Moreover, the controlled opening allows for a gradual release of pressure, rather than a sudden and uncontrolled burst.
In an embodiment, the venting assembly (107) may include a vent cap (114) made of polymeric, disposed over a vent hole (112) of the vent membrane (108). The vent cap (114) serves to close the vent hole (112) to protect the vent membrane (108) from mechanical damage during manufacturing, handling, or assembly. It is configured not to interfere with the operation of the venting mechanism during pressure relief.
In an embodiment, the burst pressure at which the vent membrane (108) is configured to directional rupture (120) can be tuned based on material selection, groove geometry, and thickness profile.
In an embodiment, the venting assembly (107) is configured to activate upon internal pressure reaching or exceeding the threshold pressure of 11 bar to 18 bar.
In a preferred embodiment, the venting assembly (107) is configured to activate upon internal pressure reaching or exceeding the threshold pressure of 17 bar.
In an embodiment, the vent membrane (108) may be made from aluminium grade materials, preferably in O-temper (annealed) condition, which exhibit high ductility and consistent yield strength. These materials are well-suited for groove formation by stamping and ensure stable burst performance over time.
In an embodiment, the vent membrane (108) has yield strength of 60MPa to 80Mpa, with ultimate tensile strength of 100MPa to 120MPa, elongation of 25% to 50%.
In a preferred embodiment, the vent membrane (108) has yield strength of 65MPa, with ultimate tensile strength of 110MPa, elongation of 40%.
In one embodiment, the venting assembly (107) includes at least one current collector plate (106) positioned within the cylindrical casing (100). The closure element or the bottom lid (104) is configured to enclose the current collector plate (106) and support the mounting of the vent membrane (108). The current collector plate (106) is electrically coupled to the jelly roll electrode structure (102) and serves as an electrical and mechanical interface.
Example
In one exemplary embodiment, a venting assembly (107) was configured for integration in a 4695 cylindrical lithium-ion cell (500) employing a jelly roll electrode structure (102). The assembly was mounted to the bottom lid (104) of the cell (500) and included a vent membrane (108) made from O-temper aluminium (Aluminium MFX O-grade) with a uniform base thickness of 0.50 mm. A spline-curve path (110B) groove was formed in the vent membrane (108) using a precision stamping process, which reduces the groove region thickness to approximately 0.20 mm. The groove extended from a first terminal point to a second terminal point in a continuous curved path, and included at least one curvature inflection zone (118) along its length.
To validate the effectiveness of the proposed configuration of the venting assembly (107) of the present disclosure, a finite element analysis (FEA) simulation was conducted to evaluate the mechanical strain and stress distribution under increasing internal pressure, to replicate thermal runaway or overpressure scenarios. FIG. 5A is a top-view illustrating the high strain zone (122) around the curvature inflection zone (118) of the venting membrane under internal pressure, in accordance with the present disclosure.
Simulation setup:
Membrane material: Aluminium (O-temper, annealed)
Weld area thickness: 0.50 mm
Vent membrane thickness: 0.2 mm
Groove Thickness: 0.1 mm at spline path
Groove width: 0.2mm at the spline path
Groove shape: Spline curve with curvature inflection at mid-length
Boundary conditions: Fully clamped at welded edges
Load condition: Uniform internal pressure ramped from 0 to 20 bar
Key simulation results:
Strain Localization and Rupture Prediction: The strain distribution showed localized maximum equivalent total strain (~0.75 mm/mm) aligned precisely with the spline-curve path (110B), particularly at the curvature inflection zones (118). The total strain map confirmed that no strain accumulation occurred in the thicker membrane regions, confirming that the groove was effectively acting as a stress-concentration path. Crack propagation was observed to proceed along the spline direction, validating the mechanism for directional rupture (120). Also, as seen in the cross-sectional strain visualization, failure initiates and propagates only in the groove region, confirming controlled and localized directional rupture (120). Further, the directional rupture (120) propagated only along the central portion of the spline curve, and the simulation indicated that membrane segments near both terminal ends remained mechanically affixed to the bottom lid (104). This demonstrates partial rupture without full detachment, reducing the likelihood of fragment ejection. At equivalent mechanical strain of 40% (or 0.4), the internal pressure within the cell (500) noted as 17Bar. FIG. 5B is a sectional-view illustrating the high strain zone (122) around the curvature inflection zone (118) of figure 5A under internal pressure, in accordance with the present disclosure.
The vent membrane (108) retained structural integrity outside the groove zone, and no uplift or deformation of the welded region was observed, which confirms suitability for multi-cell (500) module integration without compromising safety.
Stress behavior – von Mises analysis:
The von Mises stress peaked at 203 MPa, concentrated along the inner edges of the groove, especially at curvature changes. The stress profile strongly aligns with the groove geometry, which confirms that strain zone (122) localization is mechanically induced by the spline contour.
Directional deformation consistency:
Directional deformation mapping revealed negligible uplift or radial deformation outside the groove area. The deformation was contained to the spline groove path, which confirms suitability for multi-cell (500) module integration without compromising safety.
FIG. 6A-6B is a simulation plot illustrating von Mises stress (122) distribution along the spline-curve path (110B) under internal pressure build-up, showing localized stress concentration at the curvature inflection zones (118).
The experimental results confirm that the venting assembly (107) featuring a spline-curve path (110B) profile (110A), combined with localized thickness reduction, promotes rupture initiation at the desired burst pressure range (14 ± 4 bar). The groove profile (110A) effectively functions as a mechanically tuned strain zone (122) concentrator, ensuring directional tear propagation, partial rupture without full detachment, and safe internal gas release through the vent hole (112) provided in the top plate (104) of the cell (500). The vent cap (114) operatively closes the vent hole (112).
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENT
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a venting assembly for an electrochemical cell, that:
• ensures reliable, controlled, and safe release of internal gas pressure under abnormal operating conditions such as thermal runaway, overcharging, or internal short circuit;
• has a spline-curve groove profile on a vent membrane, which enables localized strain concentration and predictable rupture initiation, thereby overcoming the limitations of conventional linear or circular groove configurations;
• provides a directional rupture path defined by a continuously extending spline-curve, which ensures that the membrane tears along a controlled path and avoids random or radial crack propagation;
• includes a region of reduced thickness at the groove profile and a surrounding region of increased thickness, such that localized rupture can be achieved at a lower and predefined burst pressure, while maintaining structural weldability;
• offers partial rupture of the vent membrane, thereby allowing the torn section to remain mechanically attached to the closure element, thereby preventing fragment ejection, short-circuit risks, and obstruction of gas flow paths; and
• forms the groove profile using a high-speed stamping process, thereby supporting cost-effective and scalable manufacturing suitable for large-volume production of lithium-ion battery cells.
The disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully revealed the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. , Claims:WE CLAIM:
1. A venting assembly (107) for an electrochemical cell (500), wherein the electrochemical cell (500) comprises a jelly roll electrode structure (102) housed within a cylindrical casing (100), said venting assembly (107) comprising:
• at least one lid (104) configured to seal at least one axial end of the cylindrical casing (100);
• a vent membrane (108) configured to be fitted on an operative surface of said lid (104), said vent membrane (108) configured to vent gas; and
• a groove profile (110A) configured on an operative surface of said vent membrane (108), said groove profile (110A) configured to concentrate mechanical strain on said vent membrane (108),
wherein said groove profile (110A) comprises a spline-curve path (110B) extending across at least a portion of said vent membrane (108), said spline-curve path (110B) having at least one curvature inflection zone (118) configured to enhance strain localization and generate a directional rupture path (120) along said vent membrane (108) in response to pressure build-up within the cell (500) upon exceeding a predetermined threshold, wherein said directional rupture path (120) is configured to release internal gas in a controlled manner through said vent membrane (108).
2. The venting assembly (107) as claimed in claim 1, wherein said spline-curve path (110B) extends continuously between a first terminal point and a second terminal point on said vent membrane (108) to form a directional rupture (120) path during pressure build-up within the cell (500).
3. The venting assembly (107) as claimed in claim 2, wherein said vent membrane (108) comprises a first thickness in a region surrounding said groove profile (110A) and a second, reduced thickness at said groove profile (110A) to facilitate localized rupture around said defined path under internal gas pressure.
4. The venting assembly (107) as claimed in claim 3, wherein said lid includes a top lid (not shown) and a bottom lid (104), configured to seal the axial ends of the cylindrical casing (100) respectively, wherein said vent membrane (108) is fitted to the lower operative surface of said bottom lid (104) by means of welding, preferably by means of a laser welding.
5. The venting assembly (107) as claimed in claim 4, wherein said first thickness is in the range of 0.45 mm to 0.55mm in a region surrounding said groove profile (110A) to facilitate welding and said second thickness is in the range of 0.15 mm to 0.25mm at said groove profile (110A) to facilitate localized rupture.
6. The venting assembly (107) as claimed in claim 1, wherein said groove profile (110A) is formed by the stamping process.
7. The venting assembly (107) as claimed in claim 5, wherein said groove profile (110A) is configured to cause partial rupture of said vent membrane (108) without full detachment such that a portion of said vent membrane (108) remains affixed to said bottom lid (104) after venting to facilitate controlled release of gas.
8. The venting assembly (107) as claimed in claim 1, further includes a polymeric vent cap (114), configured to be disposed on said vent membrane (108).
9. The venting assembly (107) as claimed in claim 1, wherein said groove profile (110A) is configured to rupture upon exceeding the predetermined threshold pressure in the range of 14 ± 4 bar.
10. The venting assembly (107) as claimed in claim 1, wherein said vent membrane (108) is preferably selected from aluminium or aluminium alloys.
11. The venting assembly as claimed in claim 1, includes at least one current collector plate (106), wherein said lid (104) is configured to enclose said current collector plate (106) with said vent membrane (108).

Dated this 25th Day of April 2025

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI