Electrochemical cell safety vent

An exhaust device, electrochemical technology, used in electrochemical generators, aqueous electrolyte batteries, batteries, etc., can solve the problems of small size and reducing battery capacity

Inactive Publication Date: 2001-10-03
MOLTECH POWER SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, the exhaust must be small so a

Method used

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  • Electrochemical cell safety vent
  • Electrochemical cell safety vent
  • Electrochemical cell safety vent

Examples

Experimental program
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Example Embodiment

[0019] Detailed description of preferred embodiments

[0020] The sealed secondary battery must be ventable in order to release the internal pressure generated under transient conditions other than normal operating conditions. If the gas pressure exceeds the set exhaust pressure and can be released smoothly, the pressure will be limited. If the amount of gas generated exceeds the exhaust amount or the exhaust device is blocked, the internal pressure may increase rapidly. When softened plastics and similar low-melting materials are used in batteries, the risk of clogging of exhaust devices under high temperature conditions will increase. In the presence of materials and conditions that may cause clogging of the exhaust device, a larger and open exhaust area helps to ensure that the exhaust device will not be blocked under destructive pressures. In order to provide a larger exhaust area required for the thermal liquefied solid to be discharged from the secondary battery, the present...

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Abstract

A safety vent is provided for incorporation into sealed electrochemical cells. The vent is particularly applicable to cells experiencing transient conditions producing pressures above 250 psi (17.6 kg/cm2). By configuring a cover plate to plastically deform at elevated pressures, an increased venting area can be produced. The increased venting area allows for venting of solid matter which may be forced into vent holes during high temperatures and pressures. Effective plastic deformation is obtained by proper selection of a ductile material and cover plate thickness. By ensuring that vent clogging does not occur, pressures are limited and the integrity of the cell is maintained. By incorporating this vent into a cell, methods of successfully passing industry standard test procedures for secondary cells are provided. The vent also includes an elastomeric sealing element which is captured between the cover plate and a rigid upper plate. The upper plate has a skirt that covers the sealing element but is lifted out of the way of vented matter by the deforming cover plate. Testing of example nickel-metal hydride based Cs cells demonstrate successful survival of a "hot plate" and "continuous overcharge" test procedures. The invention includes cells having increased safety by incorporation of the novel vent structure.

Description

Background of the invention [0001] The present invention relates to an exhaust device arranged in a container for use in a pressurized environment or pressurized during normal use or abnormal operation. More particularly, the present invention relates to a safety vent device capable of effectively venting in the event of an overpressure that occurs occasionally during use of a rechargeable electrochemical cell. [0002] Due to improved performance and energy density, rechargeable electrochemical cells are increasingly used as power sources for many kinds of devices. These secondary batteries may be classified as "vented type" or "sealed type" in terms of design and usage. Vented batteries release gases during normal operational use. A low-pressure venting mechanism is incorporated in many types of venting type batteries to achieve such a venting effect. Sealed batteries are usually pressurized and not vented under normal operating conditions. The operating pressure of a se...

Claims

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Application Information

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IPC IPC(8): H01M2/12H01G9/12H01M6/08H01M6/50H01M10/30H01M10/34H01M10/42
CPCH01G9/12H01M2200/20H01M10/345H01M2/1288H01M6/08H01M10/4228H01M2/1229H01M50/325H01M50/342Y02E60/10
Inventor P·E·帕特
Owner MOLTECH POWER SYST
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