End cap assembly for an electrochemical cell

In an electrochemical cell having an open ended cylindrical housing and an end cap assembly inserted therein closing said housing, said cell having a positive and a negative terminal, said end cap assembly comprising an electrically insulating sealing disk, said insulating sealing disk having an elongated electrically conductive current collector passing therethrough, the current collector being in electrical contact with a cell terminal, the improvement comprising:

• the end cap assembly comprising a support disk comprising metal, and the insulating sealing disk underlying said support disk when the cell is viewed in vertical position with the end cap assembly on top, wherein said insulating disk electrically insulates the support disk from the cell housing;
• said support disk being of single piece metallic construction having a convoluted surface and at least one aperture therethrough;
• said insulating disk having a convoluted surface wherein a portion of its surface underlies said aperture in said support disk when the cell is viewed in vertical position with the end cap assembly on top,
• wherein said insulating disk comprises a plastic material having a downwardly extending wall slanted at an angle between 40 and 80 degrees from the cell's central longitudinal axis, said downwardly extending surface of said insulating disk extends downwardly from a high point thereon to low point thereon, said high point being closer to the cell's central longitudinal axis than said low point when the cell is viewed in vertical position with the end cap assembly on top, wherein said support disk has a downwardly extending surface slanted at an angle between 40 and 80 degrees from the cell's central longitudinal axis, said downwardly extending surface of the support disk extends downwardly from a high point thereon to low point thereon, said high point being closer to the cell's central longitudinal axis than said low point when the cell is viewed in vertical position with the end cap assembly on top, wherein the downwardly extending wall of the insulating disk comprises a rupturable membrane underlying at least a substantial portion of the downwardly extending surface of said support disk, wherein at least one aperture in said support disk penetrates through said downwardly extending surface of said support disk, wherein a portion of said rupturable membrane underlies and abuts said aperture,
• said portion of said insulating disk underlying said aperture having a groove on a side of its surface facing the cell interior, said groove having an open end and opposing closed base wherein the base of said groove forms a thinned rupturable membrane abutting said aperture in said support disk, whereby when gas pressure within the cell rises, said rupturable membrane penetrates through said aperture and ruptures thereby releasing gas into the surrounding environment through said aperture.

In an electrochemical cell having an open ended cylindrical housing and an end cap assembly inserted therein closing said housing, said cell having a positive and a negative terminal, said end cap assembly comprising a terminal end cap and an electrically insulating sealing disk, said insulating disk having an elongated electrically conductive current collector passing therethrough and in electrical contact with said terminal end cap, and the edge of said housing being crimped over the peripheral edge of said insulating sealing disk to form a cell shoulder along the line of crimp, the improvement comprising:

• said housing comprises steel and having a wall thickness between 4 and 8 mils (0.10 and 0.20 mm),
• the end cap assembly comprising a support disk of single piece metallic construction having a convoluted surface and at least one aperture therethrough, said support disk underlying said terminal end cap and said insulating sealing disk underlying said support disk when the cell is viewed in vertical position with the end cap assembly on top, wherein the insulating disk electrically insulates said support disk from the cell housing;
• said insulating disk comprising plastic material and having a downwardly extended wall extending downwardly towards the cell interior, said downwardly extending wall of said insulating sealing disk slanted downwardly from a high point thereon to low point thereon at an angle of between 40 and 80 degrees from the cell's central longitudinal axis, said high point being closer to the cell's central longitudinal axis than said low point when the cell is viewed in vertical position with the end cap assembly on top, wherein a portion of said downwardly extending wall of the insulating disk underlies said aperture in said support disk when the cell is viewed in vertical position with the end cap assembly on top, said portion of said downwardly extending wall of said insulating disk having a groove on a side thereof facing the cell interior, said groove having an open end and opposing closed base, wherein the base of said groove forms a thinned rupturable membrane abutting said aperture in said support disk, whereby when gas pressure within the cell rises said rupturable membrane penetrates through said aperture and ruptures thereby releasing gas into the surrounding environment through said aperture.