Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to battery and more particularly to a current collector lid for a cylindrical battery cell.
BACKGROUND
[002] Generally, a cylindrical battery cell mainly includes a cylindrical can and an electrode assembly. The cylindrical can is usually made of steel or aluminum, which serves as both the container and one of the electrodes (typically the negative terminal) of the cylindrical battery cell. Typically, the electrode assembly is provided in the form of a jelly-roll configuration is formed by tightly winding the positive and negative electrodes (cathode and anode) with a separator in between, is placed inside the cylindrical can. An electrolyte is introduced in the jelly roll, which enables the movement of ions between the electrodes during charge and discharge cycles. The separator which is made from a microporous polymer keeps the two electrodes from touching while allowing the flow of ions. The cylindrical battery cell further includes current collectors which are connected to the electrodes to ensure efficient electron flow in and out of the cylindrical battery cell.
[003] Typically, in a large format cylindrical battery cells, the safety components such as a current interrupt device (CID), and a positive temperature coefficient (PTC) current limiting device are excluded from the cell assembly to improve the overall energy density of the cell. In such cells, a venting portion is provided on a current collector as a primary safety feature and the venting portion is designed as weakened portion which is configured to open when the internal pressure of the casing exceeds a predetermined threshold. Conventionally, the venting portion of the current collector is positioned nearer to a core of the jelly roll or the center of the current collector to facilitate maximum connection between the electrode tabs and the current collector. For instance, the diameter of the venting portion is typically situated close to one-fourth of the overall diameter of the current collector. However, it has been observed that the smaller diameter or area of the venting portion is inadequate to generate the necessary force for opening the vent when the internal pressure of the cell reaches a threshold value, thereby compromising the safety of the cell. Moreover, increasing the area of the venting portion to address the insufficiency of force results in a reduction of the contact area between the current collector and the electrode tab portions. Consequently, this diminishes the electrical connectivity of the cell while elevating the direct current internal resistance, thereby affecting the performance of the cell.
[004] Further, the cylindrical battery cell includes a closing pin which is pressed against a bottom current collector lid and a sealing plug of the cylindrical battery cell after filling the electrolyte into the jelly roll. A flange of the closing pin may protrude outside the bottom current collector lid such that the flange of the closing pin is disposed below the bottom current collector lid which in turn may result in improper seating of the cylindrical battery cell on a floor.
[005] Therefore, there exists a need for a current collector lid for a cylindrical battery cell which obviates the aforementioned drawbacks.
OBJECTS
[006] The principal object of embodiments herein is to provide a current collector lid for a cylindrical battery cell.
[007] Another object of embodiments herein is to provide the current collector lid which facilitates gas venting operation and better contact with electrode tabs of a jelly roll of the cylindrical battery cell.
[008] Another object of embodiments herein is to provide the current collector lid which facilitates stable seating of the cylindrical battery cell on a floor such that there is a clearance between a closing pin of the cylindrical battery cell and the floor.
[009] These and other objects of embodiments herein will be better appreciated and understood when considered in conjunction with following description and accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[0010] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0011] Fig. 1 depicts an exploded view of a cylindrical battery cell, according to embodiments as disclosed herein;
[0012] Fig. 2 depicts a sectional view of the cylindrical battery cell with detailed view of a current collector lid, according to embodiments as disclosed herein;
[0013] Fig. 3 depicts a perspective view of the current collector lid of the cylindrical battery cell, according to embodiments as disclosed herein;
[0014] Fig. 4 depicts another perspective view of the current collector lid showing a gas venting groove, according to embodiments as disclosed herein;
[0015] Fig. 5 illustrates sections of the current collector lid positioned at various planes, according to embodiments as disclosed herein; and
[0016] Fig. 6 illustrates the current collector lid, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed 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.
[0018] The embodiments herein achieve a current collector lid for a cylindrical battery cell. Referring now to Figs. 1 to 6, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0019] Fig. 1 depicts an exploded view of the cylindrical battery cell (10), according to embodiments as disclosed herein. In an embodiment, the cylindrical battery cell (10) includes a current collector lid (100), a battery cell jelly roll (200), a cylindrical can (300), a closing pin (400), a sealing plug (500), a top current collector (600), an insulator (700), a rivet gasket (800) and a rivet (900). The jelly roll (200) is formed by tightly winding the positive and negative electrodes (cathode and anode) with a separator in between. The cylindrical can (300) is adapted to house the jelly roll (200). The sealing plug (500) is received by a central hollow tubular section (103) (as shown in fig. 2) of the current collector lid (100) to prevent leakage of electrolyte from the core (200C) of jelly roll (200). The closing pin (400) is pressed against the current collector lid (100) and the sealing plug (500) after filling the electrolyte into a core of the jelly roll (200). The insulator (700) is interposed between the top current collector (600) and the cylindrical can (300) to prevent short circuit. The top current collector (600) is adapted to be connected to electrode tabs of the jelly roll (200) and the rivet (900). The rivet gasket (800) is interposed between the cylindrical can (300) and the rivet (900) to insulate the rivet (900) from the cylindrical can (300) thereby preventing short circuit since the cylindrical can (300) is welded to the current collector lid (100). Further, the rivet gasket (800) is configured to provide a sealing between the rivet (900) and the cylindrical can (300) to prevent leakage as the rivet gasket (800) is compressed to 30 to 40% between the rivet (900) and the cylindrical can (300). The rivet (900) is adapted to facilitate access terminal and to hold the rivet gasket (800). In one embodiment, the top current collector (600) is configured to act as a cathode current collector which is connected to positive electrode tabs of the jelly roll (200), and the current collector lid (100) is configured to act as an anode current collector which is connected to negative electrode tabs of the jelly roll (200). In another embodiment, the top current collector (600) is configured to act as the anode current collector which is connected to negative electrode tabs of the jelly roll (200), and the current collector lid (100) is configured to act as the cathode current collector which is connected to positive electrode tabs of the jelly roll (200).
[0020] Fig. 2 depicts a sectional view of the cylindrical battery cell (10) with detailed view of the current collector lid (100), according to embodiments as disclosed herein. In an embodiment, the current collector lid (100) includes a first section (102), a central hollow tubular section (103), a second section (104), at least one gas venting groove (105), a third section (106) and a seating flange (108). The first section (102) of the current collector lid (100) is positioned on a first plane (P1) (as shown in fig. 5). A distance between a top surface (102T) (as shown in fig. 6) of the first section (102) of the current collector lid (100) and a bottom surface of the jell roll (200) is in the range of 0.25 mm to 0.6 mm.
[0021] The central hollow tubular section (103) of the current collector lid (100) transversely extends from the first section (102) in a direction towards a core (200C) (as shown in fig. 2) of the jelly roll (200). The central hollow tubular section (103) and the jelly roll (200) defines a first space (S1) (as shown in fig. 2) therebetween. The first section (102) of the current collector lid (100) and the jelly roll (200) defines a second space (S2) (as shown in fig. 2) therebetween, wherein the first space (S1) and the second space (S2) is adapted to allow gas flow towards the second section (104). An outer diameter of the central hollow tubular section (103) is in the range of 4.5 mm to 9 mm. An inner diameter of the central tubular section (103) is in the range of 3 mm to 7 mm. A radial distance between an outer circumference of the first section (102) and a central axis (100X) (as shown in fig. 6) of the lid (100) is in the range of 2 mm to 7 mm. The central hollow tubular section (103) of the current collector lid (100) is adapted to accommodate an electrolyte infiltration nozzle (not shown) during filling of electrolyte into the core (200C) of the jelly roll (200).
[0022] The second section (104) of the current collector lid (100) is positioned on a second plane (P2) (as shown in fig. 5) and radially extend outwards with respect to the first section (102). The second plane (P2) on which the second section (104) is positioned thereon is below and spaced away from the first plane (P1) on which the first section (102) is positioned thereon. The second section (104) of the current collector lid (100) and the jelly roll (200) defines a third space (S3) (as shown in fig. 2) therebetween to accumulate the gas thereof. A distance between a top surface (104T) (as shown in fig. 6) of the second section (104) of the current collector lid (100) and the bottom surface of the jelly roll (200) is in the range of 0.6 mm to 0.8 mm. A radial distance between an outer circumference of the second section (104) and the central axis (100X) of the lid (100) is in the range of 12 mm to 16 mm.
[0023] The gas venting groove (105) is provided on the second section (104) in a circular pattern, wherein the gas venting groove (105) is configured to open thereby facilitating venting of gas to outside when pressure inside the cylindrical battery cell (10) exceeds a predefined pressure threshold during thermal runway condition. A distance between the gas venting groove (105) and the bottom surface of the jelly roll (200) is in the range of 0.5 mm to 0.8 mm.
[0024] The third section (106) is positioned on a third plane (P3) (as shown in fig. 5) and radially extend outwards with respect to the second section (104). The third section (106) is connected to the jelly roll (200). For example, the third section (106) of the current collector lid (100) is directly welded to electrode tabs of the jelly roll (200). The third plane (P3) on which the third section (106) is positioned thereon is above and spaced away from the first plane (P1) on which the first section (102) is positioned thereon. A radial distance between an outer circumference of the third section (106) and the central axis (100X) of the lid (100) is in the range of 20 mm to 24 mm.
[0025] The seating flange (108) is positioned on a fourth plane (P4) (as shown in fig. 5) and radially extend outwards with respect to the third section (106). The seating flange (108) is connected to the cylindrical can (300) of the cylindrical battery cell (10). For example, the seating flange (108) of the current collector lid (100) is welded to the cylindrical can (300) along its circumference. The fourth plane (P4) on which the seating flange (108) is positioned thereon is below and spaced away from the second plane (P2) on which the first section (102) is positioned thereon. A radial distance between an outer circumference of the seating flange (108) and the central axis (100X) of the lid (100) is in the range of 21 mm to 25 mm.
[0026] A distance between the top surface (104T) (as shown in fig. 6) of the second section (104) and the top surface (102T) (as shown in fig. 6) of the first section (102) is in the range of 0.15 mm to 0.5 mm. A distance between a top surface (108T) (as shown in fig. 6) of the seating flange (108) and the top surface (104T) of the second section (104) is in the range of 0.15 mm to 0.5 mm. A thickness of each of the first section (102), the second section (104), the third section (106) and the seating flange (108) of the current collector lid (100) is in the range of 0.3 mm to 0.8 mm. Further, an overall height of the current collector lid (100) is in the range of 1 mm to 3 mm. For example, a distance between the bottom surface (108B) of the seating flange (108) and the top surface (106T) of the third section (106) of the current collector lid (100) is in the range of 1 mm to 3 mm. A radial distance between the gas venting groove (105) and the central axis (100X) (as shown in fig. 6) of the current collector lid (100) is in the range of 9 mm to 13 mm.
[0027] In an embodiment, a fourth space (S4) (as shown in figs. 2 and fig. 6) is defined between a bottom surface (102B) (as shown in fig. 6) of the first section (102) and a bottom surface (104B) (as shown in fig. 6) of the second section (104), wherein the fourth space (S4) is adapted to accommodate a flange (402) (as shown in fig. 2) of the closing pin (400) of the cylindrical battery cell (10) thereof in which the flange (402) of the closing pin (400) is co-planar to the bottom surface (104B) of the second section (104) of the current collector lid (100) when the flange (402) of the closing pin (400) is pressed against the first section (102) of the current collector lid (100). Thus, a clearance is provided between the closing pin (400) of the cylindrical battery cell (10) and floor which enables the seating flange (108) of the current collector lid (100) to provide a stable seating of the cylindrical battery cell (10) on the floor. The flange (402) of the closing pin (400) is disposed above and spaced away from a bottom surface (108T) ) (as shown in fig. 6) of the seating flange (108).
[0028] The technical advantages of the current collector lid (100) are as follows. The current collector lid (100) facilitates gas venting operation and better contact with electrode tabs of the jelly roll (200) of the cylindrical battery cell (10). The current collector lid (100) facilitates stable seating of the cylindrical battery cell (10) on a floor such that there is a clearance between the closing pin (400) of the cylindrical battery cell (10) and the floor.
[0029] The foregoing description of the specific embodiments will so fully reveal 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 embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.
, Claims:We claim:
1. A current collector lid (100) for a cylindrical battery cell (10) having a jelly roll (200), the current collector lid (100) having:
a first section (102) positioned on a first plane (P1);
a central hollow tubular section (103) transversely extending from the first section (102) in a direction towards a core (200C) of the jelly roll (200);
a second section (104) positioned on a second plane (P2) and radially extend outwards with respect to the first section (102);
a third section (106) positioned on a third plane (P3) and radially extend outwards with respect to the second section (104); and
a seating flange (108) positioned on a fourth plane (P4) and radially extend outwards with respect to the third section (106).
2. The current collector lid (100) as claimed in claim 1, wherein the third section (106) is connected to the jelly roll (200); and
the seating flange (108) is connected to a cylindrical can (300) of the cylindrical battery cell (10).
3. The current collector lid (100) as claimed in claim 1, wherein the central hollow tubular section (103) and the jelly roll (200) defines a first space (S1) therebetween;
the first section (102) of the current collector lid (100) and the jelly roll (200) defines a second space (S2) therebetween, wherein the first space (S1) and the second space (S2) is adapted to allow gas flow towards the second section (104); and
the second section (104) of the current collector lid (100) and the jelly roll (200) defines a third space (S3) therebetween to accumulate the gas thereof.
4. The current collector lid (100) as claimed in claim 3, wherein the current collector lid (100) includes at least one gas venting groove (105) provided on the second section (104), wherein the gas venting groove (105) is configured to open thereby facilitating venting of gas to outside when pressure inside the cylindrical battery cell (10) exceeds a predefined pressure threshold.
5. The current collector lid (100) as claimed in claim 1, wherein the second plane (P2) on which the second section (104) is positioned thereon is below and spaced away from the first plane (P1) on which the first section (102) is positioned thereon;
the third plane (P3) on which the third section (106) is positioned thereon is above and spaced away from the first plane (P1) on which the first section (102) is positioned thereon; and
the fourth plane (P4) on which the seating flange (108) is positioned thereon is below and spaced away from the second plane (P2) on which the first section (102) is positioned thereon.
6. The current collector lid (100) as claimed in claim 5, wherein a distance between a top surface (104T) of the second section (104) and a top surface (102T) of the first section (102) is in the range of 0.15 mm to 0.5 mm;
a distance between the top surface (102T) of the first section (102) and a top surface (106T) of the third section (106) is in the range of 0.25 mm to 0.6 mm;
a distance between a top surface (108T) of the seating flange (108) and the top surface (104T) of the second section (104) is in the range of 0.15 mm to 0.5 mm;
a thickness of each of the first section (102), the second section (104), the third section (106) and the seating flange (108) of the current collector lid (100) is in the range of 0.3 mm to 0.8 mm; and
an overall height of the current collector lid (100) is in the range of 1 mm to 3 mm.
7. The current collector lid (100) as claimed in claim 3, wherein a distance between the gas venting groove (105) and a central axis (100X) of the current collector lid (100) is in the range of 9 mm to 14 mm;
a distance between the gas venting groove (105) and the jelly roll (200) is in the range of 0.5 mm to 0.8 mm.

8. The current collector lid (100) as claimed in claim 6, wherein a distance between the top surface (102T) of the first section (102) of the current collector lid (100) and a bottom surface of the jell roll (200) is in the range of 0.25 mm to 0.6 mm;
a distance between the top surface (104T) of the second section (104) of the current collector lid (100) and the bottom surface of the jelly roll (200) is in the range of 0.6 mm to 0.8 mm; and
a distance between an outer surface of the central hollow tubular section (103) and an outer surface of the jelly roll (200) is in the range of 0.3 mm to 0.5 mm.
9. The current collector lid (100) as claimed in claim 7, wherein an outer diameter of the central hollow tubular section (103) is in the range of 4.5 mm to 9 mm;
an inner diameter of the central tubular section (103) is in the range of 3 mm to 7 mm;
a radial distance between an outer circumference of the first section (102) and the central axis (100X) of the lid (100) is in the range of 2 mm to 7 mm;
a radial distance between an outer circumference of the second section (104) and the central axis (100X) of the lid (100) is in the range of 12 mm to 16 mm;
a radial distance between an outer circumference of the third section (106) and the central axis (100X) of the lid (100) is in the range of 20 mm to 24 mm; and
a radial distance between an outer circumference of the seating flange (108) and the central axis (100X) of the lid (100) is in the range of 21 mm to 25 mm.
10. The current collector lid (100) as claimed in claim 2, wherein a fourth space (S4) is defined between a bottom surface (102B) of the first section (102) and a bottom surface (104B) of the second section (104), wherein the fourth space (S4) is adapted to accommodate a flange (402) of a closing pin (400) of the cylindrical battery cell (10) thereof in which the flange (402) of the closing pin (400) is co-planar to the bottom surface (104B) of the second section (104) of the current collector lid (100) when the flange (402) of the closing pin (400) is pressed against the first section (102) of the current collector lid (100),
wherein
the flange (402) of the closing pin (400) is disposed above and spaced away from a bottom surface (108T) of the seating flange (108);
the third section (106) of the current collector lid (100) is directly welded to electrode tabs of the jelly roll (200); and
the seating flange (108) of the current collector lid (100) is welded to the cylindrical can (300) along its circumference.