Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Intracell assembly having cell electrode connector
Reexamination Certificate
1999-05-28
2001-05-22
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Intracell assembly having cell electrode connector
C429S185000, C429S165000
Reexamination Certificate
active
06235422
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to batteries.
Batteries, such as alkaline batters, are commonly used as energy sources. Generally, alkaline batteries include a cathode, an anode, a separator, and an electrolytic solution. The cathode is typically formed of an active material (e.g., manganese dioxide), carbon particles, and a binder. The anode can be a gel including an active material (e.g., zinc particles). The separator is usually disposed between the cathode and the anode. The electrolytic solution, which is dispersed throughout the battery, can be a hydroxide solution.
Alkaline batteries include the conventional AA, AAA, AAAA, C, and D batteries commonly sold in stores. These conventional alkaline batteries include a cylindrical housing containing a central, cylindrical zinc gel anode surrounded by a ring-shaped manganese dioxide cathode.
These conventional batteries include a negative end and a positive end. The negative end connects with a current collector inside the housing that includes a prong extending into the anode. A seal is typically positioned above the anode and cathode to prevent anode material and cathode material from leaking. The prong of the current collector passes through the seal and then into the anode.
Mick et al., U.S. Pat. No. 5,869,205 (“the Mick patent”) describes a battery which has an enhanced “service performance” (i.e., a longer life). According to Mick, the service performance in conventional alkaline batteries is limited by the restricted “anode-to-cathode interface area” in the alkaline batteries. The Mick patent gets around this restriction by replacing the center cylindrical cavity that, for example, is the zinc anode in conventional alkaline batteries with a plurality of cylindrical cavities that together make up the anode. By replacing, for example, a central zinc anode with a zinc anode including multiple cavities, the interface area between the zinc anode and the cathode is increased, providing the enhanced service performance.
The battery described by Mick including a zinc anode having multiple cavities also includes a negative end, a current collector connected to the negative end, and a seal positioned above the anode and cathode to prevent anode and cathode material from leaking. The current collector includes a prong extending into each anode cavity and also through the seal. This means that the seal in the battery is pierced multiple times. The prongs then bend and connect at a central location above the seal.
SUMMARY OF THE INVENTION
The invention features a battery including a housing containing a first electrode, a second electrode having a plurality of cavities within the first electrode, a separator disposed between the first electrode and each of the cavities, a seal positioned above the first and second electrode, and a current collector. Significantly, although the current collector includes a prong extending into each cavity, the prongs connect to a single member through branch members beneath the seal. The member then passes through the seal and connects with the negative end of the battery. As a result, although the battery includes a multi-cavity electrode and a current collector with a prong extending into each cavity, the current collector only pierces the seal once, thus providing minimal opportunity for leakage of electrode material.
Preferably, the battery further includes a second seal positioned between the branch members and the first electrode to prevent inadvertent contact.
In a preferred embodiment, the first electrode is a cathode including manganese dioxide and the second electrode is an anode including zinc. The second electrode may include, for example, two, three, or four cavities. In one preferred embodiment, the second electrode includes two D-shaped cavities. The battery may be, for example, an AA, AAA, AAAA, C, or D battery.
In some preferred embodiments, the battery has a length and, at some position along the length of the battery, each of the cavities is a minimum distance (d
1
) from the housing and a minimum distance (d
2
) from each of the other cavities, with each ratio d
2
:d
1
for each cavity being between 1.5:1 and 2.5:1, preferably between 1.7:1 and 2.3:1, more preferably between 1.8:1 and 2.2:1, and most preferably between 1.9:1 and 2.1:1. The ratio can be determined, for example, at the mid-point along the length of the battery, or a third of the distance along the length of the battery, or two-thirds of the distance along the length of the battery. Preferably, at least 50 percent of, more preferably at least 75 percent of, and most preferably substantially the entire outer circumference of each cavity at that position fulfills this relationship. The housing preferably is cylindrical.
The minimum distance (d
1
) between a cavity and the housing can be measured by determining the minimum distance between a surface of the first electrode adjacent the cavity and a surface of the first electrode adjacent the housing. The minimum distance (d
2
) between two cavities is measured at the same position along the length of the battery by determining the minimum distance between a surface of the first electrode adjacent one cavity and a surface of the first electrode adjacent the second cavity.
Preferably, the ratio d
2
:d
1
for each cavity is an average of between 1.5:1 and 2.5:1, more preferably between 1.7:1 and 2.3:1, and most preferably between 1.8:1 and 2.2:1 or even between 1.9:1 and 2.1:1.
The invention also features a battery in which the second electrode is only a single cavity. In this battery, the current collector includes a plurality of prongs extending into the single cavity.
Other features and embodiments of the invention will be apparent from the description of the preferred embodiment thereof, and from the claims.
REFERENCES:
patent: 3043899 (1962-07-01), Coleman
patent: 4011369 (1977-03-01), Sundberg
patent: 4977043 (1990-12-01), Kadouchi et al.
patent: 5948561 (1999-09-01), Urry
patent: 431 881 (1926-07-01), None
patent: 1 496 208 (1970-05-01), None
patent: 195 02 594 A1 (1995-08-01), None
patent: 2 625 372 (1989-06-01), None
patent: 2-295063 (1990-12-01), None
patent: 7-326370 (1995-12-01), None
patent: 7-326347 (1995-12-01), None
patent: WO 00/01022 (2000-01-01), None
patent: WO 00/30196 (2000-05-01), None
Kaplan Alexander
Sargeant Sean A.
Vu Viet H.
Woodnorth Douglas
Chaney Carol
Fish & Richardson P.C.
The Gillette Company
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