Amtek Research International LLC

Robert R Waterhouse

Richard W Pekala

Chi Thuong-Le La

Jeff M Frenzel

James E Emanuel

Daniel K Lee

Weston J Wood

Daniel Wandera

Andrew Wimer

Jungseung Kim

Eric Bradley Hostetler

Cory S Rogers

Wyatt Self

Eric B Hostetler

Jeffry M Frenzel

David P Walker

Srinivas Cherukupalli

Methods of reducing acid stratification with an acid-soluble and acid-stable polymer with a high molecular weight are disclosed herein. Electrolytes and separators for an energy storage device are disclosed herein. The separator includes a coating containing an acid-soluble and acid-stable polymer with a high molecular weight. The electrolyte includes sulfuric acid and an acid-soluble and acid-stable polymer with a high molecular weight. Methods of making the separators disclosed herein and methods of making batteries are also disclosed herein.

Acid stratification mitigation, electrolytes, devices, and methods related thereto

An electrically conductive porous composite composed of an expanded microsphere matrix binding a material composition having electrical conductivity properties to form an electrically conductive porous composite is disclosed herein. An energy storage device incorporating the electrically conductive porous composite is also disclosed herein.

Dry process electrically conductive composite formation

A thin, freestanding, microporous polyolefin web with good heat resistance and dimensional stability includes an inorganic surface layer. A first preferred embodiment is a microporous polyolefin base membrane in which colloidal inorganic particles are present in its bulk structure. Each of second and third preferred embodiments is a thin, freestanding microporous polyolefin web that has an inorganic surface layer containing no organic hydrogen bonding component for the inorganic particles. The inorganic surface layer of the second embodiment is achieved by hydrogen bonding with use of an inorganic acid, and the inorganic surface layer of the third embodiment is achieved by one or both of hydrogen bonding and chemical reaction of the surface groups on the inorganic particles.

Freestanding, dimensionally stable microporous webs

Granules containing mixtures of silica powder and cross-linked rubber powder are used in the manufacture of battery separators or vehicle tires. A granule contains silica and rubber powders in proportional amounts that form a silica powder carrier within which rubber powder particles are distributed. Incorporating silica-rubber granules in the manufacturing process of polyethylene separators offers a way to limit water loss in and improve the cycle life of a deep cycle lead-acid battery. Incorporating silica-rubber granules in the manufacturing process of vehicle tires affords advantages including easier material handling, reduced production of dust, and reduction in the number of ingredients measured and added to the formulation.

Porous granules containing mixture of rubber and silica powders

Proton-conducting gel electrolytes with acid immobilized within a covalently cross-linked polymer network and composites containing the gel electrolytes provide low ionic resistance, minimize acid stratification, and prevent dendrite growth. The gel electrolytes can be formed from monomers dissolved in concentrated sulfuric acid and subsequently covalently cross-linked between the battery electrodes, or the covalently cross-linked gel electrolytes can be formed in water and subsequently exchanged into sulfuric acid. The mechanical properties of these gels can often be enhanced with the addition of silica powder, silica fiber, or other additives. In some cases, the covalently cross-linked gel electrolytes are formed in the presence of a conventional silica-filled polyethylene separator or within a low density fiber mat to provide mechanical reinforcement and controlled spacing between the battery electrodes. The covalently cross-linked gel electrolytes provide low ionic resistance, and increased power capacity of the battery, because the polymer networks can be formed at low concentrations (&#x3c;20% solids).

Covalently cross-linked gel electrolytes

A lead-acid battery separator with ultralow resistivity results from high porosity, controlled pore () size distribution, and an ionic surfactant () with a long alkyl side chain () that is anchored to the polymer matrix () of a silica-filled polyethylene separator. The surfactant cannot be easily removed or washed away and thereby imparts sustained wettability to the separator. Controlling the number of, and volume occupied by, the pores (i.e., porosity) and pore size distribution of the separator contributes to a reduction in electrical (ionic) resistivity.

Lead-acid battery separators with ultra low resistivity and sustained wettability

Preferred embodiments of a freestanding, heat resistant microporous polymer film () constructed for use in an energy storage device () implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material () to maintain porosity () and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix () in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the melting point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.

Freestanding, heat resistant microporous film for use in energy storage devices

A flexible microporous polymer sheet having first and second opposite major surfaces comprises a polymer matrix binding a filler component that exhibits high oil absorption capacity in its initial state before the start of material processing. The polymer matrix includes a polyolefin component and has three-dimensional interconnecting and interpenetrating pore and polymer networks through which the bound filler component is distributed from the first major surface to the second major surface. The polyolefin and filler components are included in amounts that result in a microporous polymer sheet having between about 75% and about 90% porosity and containing less than about 10 wt. % polyolefin component. Preferred polyolefin and filler components include ultrahigh molecular weight polyethylene and high oil absorption precipitated silica, respectively.

High porosity silica-containing microporous sheets

A microporous silica-filled polyolefin separator () has a material composition that includes a fraction of cured rubber powder exhibiting low or no porosity. The cured rubber powder is a material derived from one or both of passenger and truck tires. The cured rubber powders exhibit the properties of increasing hydrogen evolution overpotential on the negative lead electrode and of decreasing the effect of antimony deposited on the negative electrode of the lead-acid battery. Incorporation of these cured rubber powders into the formulation of a microporous silica-filled polyethylene separator results in improved electrochemical properties in deep-cycle lead-acid batteries.

Composite battery separator

A microporous polyethylene battery separator material (), for use in a flooded-cell type lead-acid battery, benefits from increased porosity, enhanced wettability, and exceptionally low electrical resistance when an electrolyte-soluble pore former is employed in the manufacturing process. The pore former () is soluble in electrolytic fluid and therefore dissolves in-situ in sulfuric acid during battery assembly. The dissolution of the pore former leaves behind additional, larger voids () in the separator material and thereby enhances ionic diffusion and improves battery performance.

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Scio, OR, United States of America

Robert R Waterhouse