Post seal for lead acid batteries

#This invention relates to post seal arrangements for lead acid batteries.

#Sealing arrangements for lead acid batteries are well known in the prior art. Many of these designs rigidly fix a battery terminal post to the cover of the battery so as to seal the battery contents. Over the life of a lead acid battery, however, plate growth is experienced, particularly with positive lead plates, resulting in movement of the terminal post. As a result, stress is generated in the battery cover. Typically, the cover is formed of an acid-resistant thermoplastic, and cover failure has been noted resulting from plate growth. Such failure may curtail a lead acid battery's life span.

#Various approaches have been taken to accommodate plate growth, including allowing for movement of the terminal post relative to the battery cover. These arrangements still provide a seal and have been referred to as “moveable” post seals. For example, moveable post seals have been developed, wherein a battery cover includes a flexible member (e.g., a bellows) that is connected to a terminal post bushing, such as in U.S. Pat. No. 4,455,356, which issued on Jun. 19, 1984 to Barrett, Jr.; U.S. Pat. No. 4,898,795, which issued Feb. 6, 1990 to Stocchiero; U.S. Pat. No. 5,053,296, which issued Oct. 1, 1991 to Stocchiero; U.S. Pat. No. 5,660,946, which issued Aug. 26, 1997 to Kump et al.; and, U.S. Pat. No. 6,312,852, which issued Nov. 6, 2001 to Wagner. With these designs, the flexible member flexes in response to outward movement of the terminal post, thereby avoiding stress build-up in the cover.

#FIG. 1 is perspective partial cut-away view of a lead acid battery;

#FIG. 2 is a cross-sectional view of a sealing arrangement in accordance with the subject invention;

#FIGS. 3a and 3b are partial cross-sectional views showing different positions of the sealing member;

#The subject invention is for use with a lead acid battery, such as that shown in partial cut away in FIG. 1 and generally designated with the reference numeral 10. The lead acid battery 10 is shown for illustrative purposes and the subject invention can be practiced with any lead acid battery known to those skilled in the art.

#The lead acid battery 10 generally includes a jar 12 within which a plurality of positive and negative plates 14 are interspersingly housed with appropriately-disposed separator(s) and electrolyte. A cover 16 is disposed over one end of the jar 12 so as to seal the contents thereof. Positive and negative plates 14 are connected respectively to a positive terminal post 18 and a negative terminal post 20 using known techniques. The terminal posts 18 and 20 extend through apertures 22 formed in the cover 16. A valve-regulated vent 24 may also be provided in the cover 16 to stabilize excessive positive and/or negative pressure within the jar 12. The parts may be formed of conventional materials (e.g., the cover 16 may be formed of acid-resistant thermoplastic, such as PVC).

#To allow for growth of the plates 14 (particularly of the positive plates) over the lifetime of the lead acid battery 10, a moveable post sealing arrangement 26 may be disposed between one or more of the terminal posts 18, 20 and their respective apertures 22. The sealing arrangement 26 allows for relative movement of the respective terminal post 18, 20 without loss of sealing integrity, and is particularly well-suited for use with the positive terminal post 18. Although the negative terminal post 20 does not substantially move over the course of the life span of the lead acid battery 10, the sealing arrangement 26 may nevertheless be used therewith.