GB2471074A

GB2471074A - Battery end cover structure

Info

Publication number: GB2471074A
Application number: GB0910173A
Authority: GB
Inventors: Changgeng Wang; Smith Wang
Original assignee: BEIJING CHUANGSHIWEINA TECHNOLOGY CO Ltd
Current assignee: BEIJING CHUANGSHIWEINA TECHNOLOGY CO Ltd
Priority date: 2009-06-15
Filing date: 2009-06-15
Publication date: 2010-12-22
Also published as: GB0910173D0

Abstract

A Lithium-ion battery having a body cover 1, said body cover 1 having an end plate 2 with substantially parallel planar upper and lower plate surfaces and a circular opening in said plate 2 defined by a wall substantially perpendicular to the said pectoral plate surfaces and meeting at least one of said surfaces in a flange, and a seal comprising an ring body (20, fig. 4), having substantially parallel planar upper and lower surfaces circular in plan, with a central aperture 24 and a central axis sealed in said aperture 24 and projecting substantially perpendicularly to the planes of said surfaces, and inclined upper and lower parametric edges 41, symmetrically positioned about a plane parallel to and equally spaced from said upper and lower surfaces, said ring body 20 being of a diameter larger than the diameter of said plate opening.

Description

Description Title

A LITHIUM-ION BATTERY

FIELD OF THE INVENTION

The present invention generally relates to a Lithium-ion battery.

BACKGROUND OF THE INVENTION

Conventionally, in sealing a Lithium-ion battery, a central axis is sealed directly to the margin defining an opening in the body cover of the battery. This is accomplished by putting an annular pellet or bead of glass or glass sinter around the central axis, placing the body cover and pin with the bead around it in a fixture, along with, typically, about multiple other body cover, putting the loaded fixture into a furnace or oven and raising the temperature to the melting point of the glass, to permit the glass to bond to the body cover and the terminal. This method is slow and expensive. The body cover surface has to be clean, the body cover occupy a large amount of space, and the energy requirements are high because the body cover is large and heavy as compared with the central axis and bead or pellet.

Ring bodies have been used, in the form of sleeves with a flange extending radically outwardly from one end, and a weld projection formed on the underside of the flange. Terminals were sealed in the sleeve, and the sleeve welded to the battery body cover along the weld projection. These ring bodies have the advantage of dense loading for treatment in the fusing furnace, but they have two disadvantages. They are expensive and difficult to make, because the weld projection is difficult to form, particularly because all elements of the weld projection (ridge) throughout the 360 degree compass of the ridge have to lie in a common plane, and the ring bodies have to be oriented in a unique direction in the fixing and in the welding. It has been known, in reefer terminals, for example, to coin a sharp edge on a body cover opening to serve as a weld projection, but that does not obviate the need for specific orientation of the terminal, which is in any event in a different environment, in which the characteristics of the materials used (thicknesses, for example) are quite different from the environment in which the seal of this invention is used.

SUMMERY OF THE INVENTION

The objects of this invention are to provide a Lithium-ion battery to avoid the above problem.

In order to solve the above problem, the present invention disclose a Lithium-ion battery having a metal body cover, said body cover having a pectoral plate with substantially parallel planar upper and lower pectoral plate surfaces and a circular opening in said pectoral plate defined by a wall substantially perpendicular to the said pectoral plate surfaces and meeting at least one of said surfaces in a flange, and a seal comprising an ring body, having substantially parallel planar upper and lower surfaces circular in plan, with a central aperture and a central axis sealed in said aperture and projecting substantially perpendicularly to the planes of said surfaces, and inclined upper and lower parametric edges, symmetrically positioned about a plane parallel to and equally spaced from said upper and lower surfaces, said ring body being of a diameter larger than the diameter of said pectoral plate opening.

In the present invention of the Lithium-ion battery, the ring body type permits dense loading of fixtures, which can be oriented in either of two directions, both for fixing and for welding, which is easy and cheap to manufacture compared with seals known heretofore, and which facilitates welding by providing a high resistance weld point at a substantially line contact around the entire periphery of the ring body.

DESCRIPTION OF THE DRAWINGS

In order that the present invention can be more readily understood, reference will now be made to the accompanying drawing to illustrate the embodiments of the present invention and wherein: FIG. 1 is a top plan view of one embodiment of universal seal of this invention; FIG. 2 is a sectional view taken along the line Il-Il of FIG. 1; FIG. 3(a) is an enlarged fragmentary detailed view of the area indicated by the lines Ill-Ill of FIG. 2 before welding; FIG. 3(b) is the fragmentary enlarged detail view shown in FIG. 3(a) after welding; FIG. 4 is an enlarged sectional view of the ring body of this embodiment, with a central axis sealed; FIG. 5 is a fragmentary sectional view of a prior art ring body.

DESCRIPTION OF PREFERRED EMBODIMENT

According to the preferred embodiment, refers to the drawing, reference numeral 1 indicates a battery body cover in the form of a lid with a pectoral plate portion 2 and a rim 3. The pectoral plate 2 has a planar outer surface 5 and a planar inner surface 6, substantially parallel to the outer surface 5. The body cover 1 is circular in plan and has in its center a circular opening 10 defined by a surface 12 that intersects the outer and inner surfaces 5 and 6 perpendicularly to those surfaces in a flange 15. If the opening 10 is punched cleanly, the arras 15 will be a right angled sharp line. However, in forming an opening in stainless steel, for example, the last part of the travel of the die by which the opening is formed is likely to produce not so much shearing as punching or tearing, and the operation produces a burr on the emerging side, as illustrated in FIG. 3(a). In any case, the opening 10 should be punched in the direction from the outer surface 5 through the inner surface 6. If a burr is formed, it constitutes the arras 15.

Referring to FIG. 5, a prior art ring body 50 is shown. The ring body 50 is in the form of a sleeve with a barrel portion 51 with a radically outwardly extending flange 52 at one end. The flange 52 has formed on it a weld projection ridge 53 extending axially in the direction of the barrel. In this device, producing the flange and weld projection ridge is difficult and expensive, and the tolerances required are stringent. In the ring body 50, a central axis is bonded in the inner opening of the barrel 51. The barrel 51 is put into the opening 10 in a lid, with the flange 52 overlying the outer surface of the lid and the ring body is welded along the weld projection 53 to the lid. It can be seen that the ring body 50 must be oriented in only one direction both in fixing and welding to a lid.

Referring now to FIGS. 1 through 4 for one illustrative embodiment of universal seal of this invention, reference numeral 20 indicates a ring body of this invention.

The ring body 20 has flat parallel surfaces 21 and 22, designated for convenience upper surface 21 and lower surface 22. The ring body 20, which is circular in plan, has a central aperture 24 defined by a cylindrical wall 25, to which a central axis 30 is bonded by means of a glass seal 32. The outer margins of the ring body 20 are defined by an outer wall 35, perpendicular to the parallel planar surfaces 21 and 22 and equidistant from them, a inclined parametric upper edge 41, and a inclined lower parametric edge 42. The angles of the inclined edges 42 and 41 are identical, and the chamfers are symmetrical with respect to a plane parallel to and equidistant from sides 21 and 22, 50 that the ring body is perfectly symmetrical with respect to that plane.

In the finished body cover, as shown in FIGS. 1, 2 and 3, one of the inclined edges 41 and 42 bears against the arras 15 of the pectoral plate opening 10, forming a line contact between the inclined edge and the arras 15. In FIG. 3(a), the arras is in the form of a burr. The ring body is shown in place, from which it is urged downwardly by the pressure of an electrode, not here shown, on the upper surface 21. When welding current is applied, the burr-arras melts to form a weld nugget as shown in FIG. 3(b), the ring body following the burr-arras as it melts, to be securely welded along its entire perimeter to the pectoral plate. The provision of a burr is advantageous in the present invention, because it is an easy way to form a very thin section to provide a high resistance weld point, hence high local current density, to initiate the weld quickly and to permit its quick completion so as not to damage the glass seal. A clean shear will also provide such a line, but as has been pointed out, it is difficult to accomplish.

Merely by way of illustration, the ring body can have an outside diameter of 0.300 inches and be 0.050 inches thick. The aperture 25 can be 0.50 inches in diameter.

The chamfer angles of the edges 41 and 42 can be, and preferably are 30 degree, and the outer surface 35 can be 0.020 inches wide. The opening 10 in the body cover can be 0280 inches in diameter, and the pectoral plate 2, 0.020 inches thick. The pin can be 0.09 inches in diameter.

In forming the seals of this invention, the formed ring bodies are placed in cavities in a fixture, with a flat side 21 or 22 up. A glass bead or pellet, with a central hole, is put in the opening 25, and pins 30 are inserted in the pellets and positioned to project an equal distance from either side of the ring body. Instead of approximately 72 lids per square foot, approximately 1400 ring bodies can be accommodated per square foot of fixture. The loaded fixture is put into an oven or furnace and the glass bead or pellet fused to the wall 25 of the opening 24 and to the central axis 30, as shown in FIG. 4. It is not important that the bead be centered axially in the opening 24, because the pin 30 is positioned by the fixture symmetrically with respect to the central plane of the ring body. It can be seen that in loading the fixture, the ring bodies can simply be distributed without regard to which of the sides 21 and 22 is uppermost.

Similarly, when the ring bodies 20 are to be welded to body cover 1, they need only be centered in the openings 10, on the side from which the die forming the opening emerged, because the ring bodies being perfectly symmetrical, it makes no difference which of the inclined edges 41 and 42 engages the arras 15. The line contact between the inclined edge and the arras 15 provides a high resistance weld point, which starts the weld easily and effectively, and at present the ring bodies can be welded to the lid at a rate of one a second and without damaging the glass weld.

It can be seen that the size of the lid or body cover for the battery is immaterial as long as the opening in the lid is sized to permit the ring body to be welded into it as has been described. Similarly, the diameter of the central axis can be varied, within limits, for example, 0.02 to 0.09 inches, without changing the dimensions or construction of the ring body. Of course, the dimensions of the ring body itself can be changed. The chamfer angles can be changed also, although the 30 degree chamfer is believed to be the optimum angle. The body cover 1, ring body 20 and central axis are preferably made of stainless steel, but other metals can be employed. The seal 32 is preferably of glass, but other sealing material can be used. Although it is convenient and preferable to have the pin 30 project symmetrically with respect to the central plane, it can be seen that it is not essential, the length of the pin and the degree of its projection from one side or the other being a matter of choice.

Whilst the above has been given by way of illustrative examples of the present invention, many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as herein set forth in the following claims.

Claims

CLAIMS1. A Lithium-ion battery having a body cover, said body cover having a pectoral plate with substantially parallel planar upper and lower pectoral plate surfaces and a circular opening in said pectoral plate defined by a wall substantially perpendicular to the said pectoral plate surfaces and meeting at least one of said surfaces in a flange, and a seal comprising an ring body, having substantially parallel planar upper and lower surfaces circular in plan, with a central aperture and a central axis sealed in said aperture and projecting substantially perpendicularly to the planes of said surfaces, and inclined upper and lower parametric edges, symmetrically positioned about a plane parallel to and equally spaced from said upper and lower surfaces, said ring body being of a diameter larger than the diameter of said pectoral plate opening.
2. The Lithium-ion battery of claim 1, wherein the angle of said inclined upper and lower parametric edges to the planes of their respective upper and lower surfaces is 30 degree, and a central, outer parametric edge surface perpendicular to said planar upper and lower surfaces.
3. The Lithium-ion battery of claim 1 wherein said body cover and said ring body are welded integrally.
4. The Lithium-ion battery of claim 1 wherein said central axis is positioned to project symmetrically with respect to said plane.