Abstract:
A sealing apparatus supplies one or more activating gases needed to produce a current generating chemical reaction in an air breathing battery, the supply of one or more activating gases being proportionally controlled to coincide with differing current loads.

Description:
FIELD OF THE INVENTION 
     This invention relates in general to the field of energy sources, and more specifically, to a sealing arrangement for regulating the discharge rate and maximum current drain of a battery. 
     BACKGROUND OF THE INVENTION 
     Battery powered devices (e.g., pagers) have historically relied on batteries as their main power source. As these devices become smaller, the battery occupies an increasing amount of space relative to the remainder of the device&#39;s size. Therefore, it is desirable to reduce the size of the battery while maintaining at least the same energy capacity as contemporary batteries. Air-breathing (e.g., zinc-air) batteries meet these requirements, and therefore, are becoming more widely used in selective call receivers. As is known, proper zinc-air battery operation relies on air availability since the internal chemical reaction that occurs in a zinc-air battery results from the oxygen-zinc reaction. 
     Contemporary zinc-air battery construction incorporates the zinc into a casing having a number of holes to allow air to reach the zinc. These holes are initially sealed to prevent the zinc from prematurely reacting with the air (which reduces the battery&#39;s shelf-life). Before using the battery to power a product, the seal(s) covering the air-holes is removed so as to allow the infiltration of air. 
     Generally, battery manufacturers attempt to produce batteries that will meet the broadest market demand. Therefore, it is common to manufacture batteries with a larger amount (or size) of holes than necessary to meet the needs of many applications. Regrettably, this practice tends to result in premature fuel exhaustion (commonly referred to as &#34;self-discharge&#34;). That is, since the zinc-air reaction is dependent upon the amount of oxygen allowed to reach the zinc, the resulting continuous chemical reaction is often in excess of the requirements of the device due to the excessive number of holes, and therefore, the amount of air supplied. Thus, a need exists for a method to regulate an air-breathing battery in which the chemical reaction may be selectively controlled depending on the power requirements of the device being operated. 
     SUMMARY OF THE INVENTION 
     In carrying out the above, there is provided in one form of the invention a method for controlling the discharge rate of an energy storage means (e.g., a battery), while providing a desired current comprising a sealing means for controlling the amount of one or more activating gases provided to the energy storage means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an illustration of a conventional zinc-air battery. 
     FIGS. 2a-2c are illustrations of a seal in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a typical air-breathing battery 10 comprises a sealed (16) outer casing 12 having a plurality of supply holes 14 for facilitating the passage of at least one activating gas (e.g., air). Before using the battery 10 to power a product or device, the seal 16 is removed such as by pulling on an integral tab 18. This allows any surrounding atmospheric gases to contact an internal chemical substance via the now exposed supply holes 14. That is, the supply holes 14 allow oxygen and other gases to reach a chemical (e.g., zinc) thereby causing a chemical reaction, which generates electrical power. A number of chemicals and gases may be used to induce the chemical reaction without varying from the intent of the invention. As will be appreciated, if an over-supply of air reaches the chemical, a larger than necessary chemical reaction occurs, which reduces the operational lifetime of the battery. Thus, exposing all of the supply holes 14 to the atmosphere results in the battery 10 self-discharging at a more rapid rate than if the air supply holes 14 were only partially exposed. This results in the battery 10 discharging more rapidly than necessary even when not powering a device or product. 
     Referring to FIGS. 2a-2c, the present invention can be seen to employ a slide mechanism 20 (20&#39; and 20&#34;) to regulate the amount of surrounding atmospheric gases that may contact internal chemical(s) of the battery 12&#39; (12&#34;). In the preferred embodiment, three openings 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;) and one optional opening 32 (32&#39;) control the battery&#39;s self-discharge and maximum current drain by allowing the power supplied to more closely match the requirements of the intended device. The number and size of these openings 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;) may vary without deviating from the intent of the invention. 
     Operationally, a receiver 48 receives a message, which is processed by a controller 46. Depending upon the position of the slide mechanism 20 (20&#39; and 20&#34;), the controller 46 activates either the low volume mode 26 (26&#39;), the high volume mode 28 (28&#39;), the vibrate mode 30 (30&#39;), or remains in the &#34;off&#34; mode 24 (24&#39;). This method of regulation is accomplished by positioning the slide mechanism 20 (20&#39; and 20&#34;) in a direction 44 so as to selectively cover the openings 32 (32&#39;), 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;), allowing the rate of air flow to the battery 12&#39; (12&#34;) to more closely match the electrical requirements of the device in which it is used (e.g., a selective call receiver). The supply holes 14&#39; of the zinc-air battery 12&#39; (12&#34;) are constantly exposed in a chamber 40, however, the atmospheric gases allowed to travel through a channel 22 and the supply holes 14&#39; of the battery 12&#39; (12&#34;) may be regulated by selectively exposing the openings 34 (34&#39;), 36 (36&#39;), and 38 (38&#39; ). 
     The channel 22 is substantially the only means of air access to the chamber 40. In the preferred embodiment, positioning the slide mechanism 20 (20&#39; and 20&#34;) over each opening 32 (32&#39;), 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;) corresponds to an &#34;off&#34; mode 24 (24&#39;), a low volume (20 mA requirement) mode 26 (26&#39;), a high volume (50 mA requirement) mode 28 (28&#39;), and a vibrate (100 mA requirement) mode 30 (30&#39;), respectively. The chemical reaction is effectively halted when the slide mechanism 20 (20&#39; and 20&#34;) is positioned in the &#34;off&#34; mode 24 (24&#39;) since no additional atmospheric gases are allowed to enter the chamber 40. The chamber 40 serves as a storage means for storing the energy source means (battery) 12&#39; (12&#34;). The opening 32 (32&#39;) may be present to provide minimal energy to maintain an optional volatile memory feature while the product is in the &#34;off&#34; mode 24 (24&#39;). Alternately, the opening 32 (32&#39;) may be eliminated if no current is required (e.g., volatile memory feature is not present) when the device is switched off, thereby eliminating the battery&#39;s self-discharge when the device is in the &#34;off&#34; mode 24 (24&#39;) for an extended period of time. Therefore, the battery 12&#39; (12&#34;) would be unable to self-discharge due to the slide mechanism 20 (20&#39; and 20&#34;) preventing atmospheric gases from reaching the chamber 40. This feature allows the user to extend the operational life of the battery 12&#39; (12&#34;) by shutting off the supply of atmospheric gases allowed to reach the battery 12&#39; (12&#34;) when the device is not in use. 
     Positioning the slide mechanism 20 (20&#39; and 20&#34;) in the low volume mode 26 (26&#39;) and the high bolume mode 28 (28&#39;) permits a voice message to be produced by a speaker 50. The low volume mode 26 (26&#39;) requires the least amount of energy and is, therefore, supplied by one opening 26 (26&#39;). The high volume mode 28 (28&#39;) requires additional energy, relative to the low power mode 26 (26&#39;), and is, therefore, supplied by openings 34 (34&#39;) and 36 (36&#39;). Positioning the slide mechanism 20 (20&#39; and 20&#34;) in the vibrate mode 30 (30&#39;) activates a vibrator 52. The vibrate mode 30 (30&#39;) requires a higher energy level than that needed by the low volume mode 26 (26&#39;) and the high volume mode 28 (28&#39;) combined, therefore, positioning the slide mechanism 20 (20&#39; and 20&#34;) in the vibrate mode 30 (30&#39;) exposes openings 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;). With all opening 34 (34&#39;), 36 (36&#39;), and 38 (38&#39;) exposed, a sufficient amount of atmospheric gases is allowed to reach the battery 12&#39; (12&#34;) to activate the vibrator 52. Thus, increasing the rate of passage of air into the battery area in response to the expected current drain of the paging receiver has been shown. This provides for increasing current producing capacity of the battery in accordance with the expected current drain of the paging receiver. 
     In the simplest form, this invention may be represented by one opening and a two position switch. In the first position, the device would be able to receive atmospheric gases, resulting in a chemical reaction and thus, available energy. In the second position, the opening would be completely closed, allowing no atmospheric gases to reach the battery 12&#39; (12&#34;), thereby extending the operational lifetime of the battery 12&#39; (12&#34;). By mechanically regulating the number of available openings in which atmospheric gases are allowed to pass, the battery&#39;s maximum current handling ability and self-discharge rate is regulated accordingly, thereby extending the life of the battery.