Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to a cylindrical battery cell and more particularly to a self-locking closing pin for the cylindrical battery cell for restricting loosening of the closing pin from a center hole of a current collector lid when the closing pin is fitted with the current collector lid.
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 terminals (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 conventional cylindrical battery cell after filling the electrolyte into the jelly roll, a sealing plug is inserted into a centre hole of a bottom current collector lid, and subsequently a closing pin is inserted into a center cavity of the sealing pin by pressing the closing pin against the bottom current collector lid and the sealing plug. When the closing pin is not fitted properly with the sealing plug or the current collector lid, there may be a high possibility of a play between the closing pin and the bottom current collector lid/ sealing plug. For example, if the closing pin is not properly fitted with the sealing plug/ the current collector lid, then the closing pin may loosen out from the current collector lid. This results in electrolyte leakage from the cylindrical battery cell thereby decreasing the safety and lifetime of the cylindrical battery cell as well as causes contamination of the electrolyte due to entry of foreign contaminants into the cylindrical battery cell which is undesirable.
[004] Therefore, there exists a need for a self-locking closing pin for a cylindrical battery cell which obviates the aforementioned drawbacks.
OBJECTS
[005] The principal object of embodiments herein is to provide a self-locking closing pin for the cylindrical battery cell for restricting loosening of the closing pin from a center hole of a current collector lid thereby restricting electrolyte leakage from the cylindrical battery cell.
[006] Another object of embodiments herein is to provide the closing pin which achieves hermetic sealing at the center hole of the current collector lid.
[007] Another object of embodiments herein is to tightly fit the closing pin against the current collector lid.
[008] Another object of embodiments herein is to eliminate the usage of a sealing plug for the cylindrical battery cell.
[009] Another object of embodiments herein is to prevent entry of contaminants into the cylindrical battery cell.
[0010] Another object of embodiments herein is to enhance safety and lifetime of the cylindrical battery cell.
[0011] Another object of embodiments herein is to provide the self-locking closing pin which is reliable and is easy to manufacture.
[0012] 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
[0013] 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:
[0014] Fig. 1 depicts an exploded view of a cylindrical battery cell with a self-locking closing pin, according to embodiments as disclosed herein;
[0015] Fig. 2 depicts a sectional view of the self-locking closing pin and a current collector lid of the cylindrical battery cell, according to embodiments as disclosed herein;
[0016] Fig. 3 depicts a sectional view of the self-locking closing pin which is locked with the current collector lid when the self-locking closing pin is fitted with the current collector lid, according to embodiments as disclosed herein;
[0017] Fig. 4 depicts a perspective view of the self-locking closing pin, according to embodiments as disclosed herein;
[0018] Fig. 5A depicts a top view of the self-locking closing pin, according to embodiments as disclosed herein;
[0019] Fig. 5B depicts a sectional view of the self-locking closing pin, according to embodiments as disclosed herein; and
[0020] Fig. 6 depicts another perspective view of the self-locking closing pin, according to embodiments as disclosed herein.
DETAILED DESCRIPTION
[0021] 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.
[0022] The embodiments herein achieve a self-locking closing pin for the cylindrical battery cell for restricting loosening of the closing pin from a center hole of a current collector lid thereby restricting electrolyte leakage from the cylindrical battery cell. Further, referring now to Figs. 1 to 6, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0023] Fig. 1 depicts an exploded view of the cylindrical battery cell (10) with the self-locking closing pin (100), according to embodiments as disclosed herein. In an embodiment, the cylindrical battery cell (10) includes a self-locking closing pin (100), a current collector lid (200), a jelly roll (300), a cylindrical can (400), a top current collector (500), an insulator (600), a rivet gasket (700) and a terminal rivet (800). The jelly roll (300) is formed by tightly winding the positive and negative electrodes (cathode and anode) with a separator in between. The cylindrical can (400) is adapted to house the jelly roll (300). The self-locking closing pin (100) is adapted to be received by a center hole (202) (as shown in fig. 2) of the current collector lid (200) when the self-locking closing pin (100) is pressed against the current collector lid (100) after filling the electrolyte into a core of the jelly roll (300). The insulator (600) is interposed between the top current collector (500) and the cylindrical can (400) to prevent short circuit. The top current collector (500) is adapted to be connected to electrode tabs of the jelly roll (300) and the terminal rivet (800). The rivet gasket (700) is interposed between the cylindrical can (400) and the terminal rivet (800) to insulate the terminal rivet (800) from the cylindrical can (400) thereby preventing short circuit since the cylindrical can (400) is welded to the current collector lid (200). Further, the rivet gasket (700) is configured to provide a sealing between the terminal rivet (800) and the cylindrical can (400) to prevent leakage as the rivet gasket (700) is compressed to 30 to 40% between the terminal rivet (800) and the cylindrical can (400). The terminal rivet (800) is adapted to facilitate access terminal and to hold the rivet gasket (700). In one embodiment, the top current collector (500) is configured to act as a cathode current collector which is connected to positive electrode tabs of the jelly roll (300), and the current collector lid (200) is configured to act as an anode current collector which is connected to negative electrode tabs of the jelly roll (300). In another embodiment, the top current collector (500) is configured to act as the anode current collector which is connected to negative electrode tabs of the jelly roll (300), and the current collector lid (200) is configured to act as the cathode current collector which is connected to positive electrode tabs of the jelly roll (300).
[0024] Figs. 4 and 5B illustrate the self-locking closing pin (100), according to embodiments as disclosed herein. In an embodiment, the self-locking closing pin (100) includes a hollow tapered body (102), a flange (104), a leg connecting section (105) and a pair of tapered legs (106A, 106B). The center hole (202) of the current collector lid (20) is chamfered to facilitate easy entry of the tapered legs (106A, 106B) and the tapered hollow body (102) of the self-locking closing pin (100) therein. Further, the tapered legs (106A, 106B) and the tapered hollow body (102) of the self-locking closing pin (100) also facilitates in easy entry of the closing pin (100) into the center hole (202) of the current collector lid (200). The flange (104) of the self-locking closing pin (100) is adapted to extend outward from a top end of the hollow tapered body (102) along its circumference. The leg connecting section (105) of the self-locking closing pin (100) is adapted to extend inside the hollow tapered body (102). For example, the leg connecting section (105) extends crosswise there between a wall (102W) (as shown in figs. 2 to 4) of the hollow tapered body (102). The leg connecting section (105) is positioned at a predefined distance from the flange (104). The leg connecting section (105) is adapted to connect the tapered leg (106A) with another tapered leg (106B). The pair of tapered legs (106A, 106B) is adapted to extend from the hollow tapered body (102) and the leg connecting section (105). One end (106f) (as shown in fig. 5B) of each tapered leg (106A, 106B) is open to the hollow tapered body (102) and another end (106s) (as shown in fig. 5B) of each tapered leg (106A, 106B) is closed. The leg connecting section (105) and the tapered legs (106A, 106B) define a space (107) there between. In an embodiment, each tapered leg (106A, 106B) includes a first wall (106AA, 106BA), a second wall (106AB, 106BB) and a bottom wall (106AC, 106BC). The first wall (106AA, 106BA) of each tapered leg (106A, 106B) is adapted to extend from the wall (102W) of the hollow tapered body (102) at its corresponding side. The first wall (106AA, 106BA) of each tapered leg (106A, 106B) is a tapered arcuate wall in which a first side portion (106Af, 106Bf) (as shown in fig. 6) of the first wall (106AA, 106BA) is connected a side portion of the second wall (106AB, 106BB), and a second side portion (106As, 106Bs) (as shown in fig. 6) of the first wall (106AA, 106BA) is connected to another side portion of the second wall (106AB, 106BB). The second wall (106AB, 106BB) of each tapered leg (106A, 106B) is adapted to extend from the leg connecting section (105) at its corresponding side. The bottom wall (106AC, 106BC) of each tapered leg (106A, 106B) is adapted to connect a bottom end of the first wall (106AA, 106BA) with a bottom end of the second wall (106AC, 106BC) thereby closing the bottom end of the tapered leg (106A, 106B). Further, the wall (102W) of hollow tapered body (102) is configured to progressively taper inward in a direction from the flange (104) to the first wall (106AA, 106BA) of the tapered legs (106A, 106B) when the closing pin (100) is not fitted to the current collector lid (200). The first wall (106AA, 106BA) of each leg (106A, 106B) is the tapered arcuate wall which is configured to progressively taper inward in a direction from the body (102) to the closed end of the tapered leg (106A, 106B) when the closing pin (100) is not fitted to the current collector lid (200). The second wall (106AB, 106BB) of each tapered leg (106A, 106B) is an upright wall when the closing pin (100) is not fitted to the current collector lid (200).
[0025] At least one of the tapered hollow body (102), the leg connecting section (105) and the tapered legs (106A, 106B) are configured to deform thereby facilitating self-locking of the closing pin (100) with the current collector lid (200) of the cylindrical battery cell (10) when the closing pin (100) is fitted with the current collector lid (200). The deformation of at least one of the tapered hollow body (102), the leg connecting section (105) and the tapered legs (106A, 106B) are caused by at least one of a pressure acting on the space (107), a circumferential force acting on outer side of the wall (102W) of the body (102) and an outer force acting on the flange (104) of the closing pin (100), thereby sealing the closing pin (100) with respect to the current collector lid (200) when the closing pin (100) is fitted with the current collector lid (200). Further, the space (107) is configured to progressively widen outward in a direction from the leg connecting section (105) to the closed end of the legs (106A, 106B) to facilitate self-locking of the closing pin (100) with the current collector lid (200) while fitting the closing pin (100) with the current collector lid (200). The body (102) of the closing pin (100) is rigidly engaged with the center hole (202) of the current collector lid (200) when the closing pin (100) is self-locked with the current collector lid (200).
[0026] The second wall (106AB, 106BB) of each tapered leg (106A, 106B) is adapted to form a tapered wall which is configured to progressively taper outward in the direction from the leg connecting section (105) to the closed end of the tapered leg (106A, 106B) when the closing pin (100) is self-locked with the current collector lid (200). The first wall (106AA, 106BA) of each leg (106A, 106B) and the wall (102W) of the body (102) is configured to taper outward in a direction from the flange (104) to the closed end of the legs (106A, 106B) when the closing pin (100) is self-locked with the current collector lid (200).
[0027] For the purpose of this description and ease of understanding, the self-locking closing pin (100) and the sizes of the components of the self-locking closing pin (100) is considered herein with respect to a large format cylindrical battery cell such as 4680 battery. However, it is also within the scope of the invention to consider the self-locking closing pin (100) to be provided in any other sizes and configurations of the cylindrical battery cell. A height of the closing pin (100) is in the range of 2.82 mm to 2.84 mm. A thickness of the flange (104) is 0.3 ± 0.05 mm. An inner diameter of the flange (104) is 4.7 ± 0.2 mm. An outer diameter of the flange (104) is 8 ± 0.1 mm. A width of the space (107) between the legs (106A, 106B) near its closed end is same as a width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) before fitting the closing pin (100) with the current collector lid (200). The width of the space (107) is 0.5 ± 0.05 mm before fitting the closing pin (100) with the current collector lid (200). The width of the space (107) between the legs (106A, 106B) near its closed end is larger than the width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) when the closing pin (100) is fitted with the current collector lid (200). The width of the space (107) between the legs (106A, 106B) near its closed end is in the range of 0.7 mm to 0.9 mm when the closing pin (100) is fitted with the current collector lid (200). The width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) is in the range of 0.45 mm to 0.55 mm when the closing pin (100) is fitted with the current collector lid (200).
[0028] The technical advantages of the self-locking closing pin (100) are as follows. The self-locking closing pin (100) is adapted to restrict a play with the center hole (202) of the current collector lid (200) to prevent loosening of the closing pin (100) from the current collector lid (200) thereby restricting electrolyte leakage from the cylindrical battery cell. The self-locking closing pin (100) achieves hermetic sealing with the center hole of the current collector lid (200). The self-locking closing pin (100) is tightly fitted with the current collector lid (200). The self-locking closing pin (100) eliminates the usage of the sealing plug in the cylindrical battery cell. The self-locking closing pin (100) prevents entry of contaminants into the cylindrical battery cell. The self-locking closing pin (100) enhances safety and lifetime of the cylindrical battery cell. The self-locking closing pin (100) is reliable and is easy to manufacture.
[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 self-locking closing pin (100) for a cylindrical battery cell (10), the self-locking closing pin (100) having:
a hollow tapered body (102);
a flange (104) extending outward from a top end of the hollow tapered body (102) along its circumference;
a leg connecting section (105) extending inside the hollow tapered body (102); and
a pair of tapered legs (106A, 106B) extending from the hollow tapered body (102) and the leg connecting section (105), wherein one end (106f) of each tapered leg (106A, 106B) is open to the hollow tapered body (102) and another end (106s) of each tapered leg (106A, 106B) is closed,
wherein
the leg connecting section (105) is adapted to connect the tapered leg (106A) with another tapered leg (106B); and
the leg connecting section (105) and the tapered legs (106A, 106B) define a space (107) therebetween.
2. The self-locking closing pin (100) as claimed in claim 1, wherein at least one of the tapered hollow body (102), the leg connecting section (105) and the tapered legs (106A, 106B) are configured to deform thereby facilitating self-locking of the closing pin (100) with a current collector lid (200) of the cylindrical battery cell (10) when the closing pin (100) is fitted with the current collector lid (200).
3. The self-locking closing pin (100) as claimed in claim 2, wherein the space (107) is configured to progressively widen outward in a direction from the leg connecting section (105) to the closed end of the legs (106A, 106B) to facilitate self-locking of the closing pin (100) with the current collector lid (200) while fitting the closing pin (100) with the current collector lid (200);
at least one of the tapered hollow body (102), the leg connecting section (105) and the tapered legs (106A, 106B) are configured to deform due to at least one of a pressure acting on the space (107), a circumferential force acting on outer side of the wall (102W) of the body (102) and an outer force acting on the flange (104) of the self-locking closing pin (100); and
the body (102) of the self-locking closing pin (100) is rigidly engaged with a center hole (202) of the current collector lid (200) when the closing pin (100) is self-locked with the current collector lid (200).
4. The self-locking closing pin (100) as claimed in claim 3, wherein each tapered leg (106A, 106B) includes:
a first wall (106AA, 106BA) extending from the wall (102W) of the hollow tapered body (102) at its corresponding side;
a second wall (106AB, 106BB) extending from the leg connecting section (105) at its corresponding side; and
a bottom wall (106AC, 106BC) adapted to connect a bottom end of the first wall (106AA, 106BA) with a bottom end of the second wall (106AC, 106BC) thereby closing the bottom end of the tapered leg (106A, 106B),
wherein
the first wall (106AA, 106BA) of each tapered leg (106A, 106B) is a tapered arcuate wall in which a first side portion (106Af, 106Bf) of the first wall (106AA, 106BA) is connected a side portion of the second wall (106AB, 106BB), and a second side portion (106As, 106Bs) of the first wall (106AA, 106BA) is connected to another side portion of the second wall (106AB, 106BB).
5. The self-locking closing pin (100) as claimed in claim 4, wherein the wall (102W) of hollow tapered body (102) is configured to progressively taper inward in a direction from the flange (104) to the first wall (106AA, 106BA) of the tapered legs (106A, 106B);
the first wall (106AA, 106BA) of each leg (106A, 106B) is the tapered arcuate wall which is configured to progressively taper inward in a direction from the body (102) to the closed end of the tapered leg (106A, 106B);
the second wall (106AB, 106BB) of each tapered leg (106A, 106B) is an upright wall;
the leg connecting section (105) is positioned at a predefined distance from the flange (104); and
the leg connecting section (105) extends crosswise therebetween the wall (102W) of the hollow tapered body (102).
6. The self-locking closing pin (100) as claimed in claim 5, wherein the second wall (106AB, 106BB) of each tapered leg (106A, 106B) is adapted to form a tapered wall which is configured to progressively taper outward in the direction from the leg connecting section (105) to the closed end of the tapered leg (106A, 106B) when the closing pin (100) is self-locked with the current collector lid (200); and
the first wall (106AA, 106BA) of each leg (106A, 106B) and the wall (102W) of the body (102) is configured to taper outward in a direction from the flange (104) to the closed end of the legs (106A, 106B) when the closing pin (100) is self-locked with the current collector lid (200).
7. The self-locking closing pin (100) as claimed in claim 1, wherein a thickness of the flange (104) is 0.3 ± 0.05 mm;
an inner diameter of the flange (104) is 4.7 ± 0.2 mm; and
an outer diameter of the flange (104) is 8 ± 0.1 mm.
8. The self-locking closing pin (100) as claimed in claim 1, wherein a width of the space (107) between the legs (106A, 106B) near its closed end is same as a width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) before fitting the closing pin (100) with the current collector lid (200);
the width of the space (107) is 0.5 ± 0.05 mm before fitting the closing pin (100) with the current collector lid (200);
the width of the space (107) between the legs (106A, 106B) near its closed end is larger than the width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) when the closing pin (100) is fitted with the current collector lid (200);
the width of the space (107) between the legs (106A, 106B) near its closed end is in the range of 0.7 mm to 0.9 mm when the closing pin (100) is fitted with the current collector lid (200); and
the width of the space (107) between the legs (106A, 106B) near the leg connecting section (105) is in the range of 0.45 mm to 0.55 mm when the closing pin (100) is fitted with the current collector lid (200).
9. The self-locking closing pin (100) as claimed in claim 2, wherein a height of the closing pin (100) is in the range of 2.82 mm to 2.84 mm.