US2011123850A1PendingUtilityA1

Electrode Separator

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Assignee: ZPOWER INCPriority: Mar 27, 2008Filed: Mar 27, 2009Published: May 26, 2011
Est. expiryMar 27, 2028(~1.7 yrs left)· nominal 20-yr term from priority
Inventors:Hieu Minh DuongGeorge W. Adamson
B29C 48/03H01M 50/457H01M 50/417H01M 50/414H01M 50/403H01M 50/446B29K 2029/04B29C 48/022B29K 2995/0077H01M 10/32B29L 2031/3468B29K 2105/243B29K 2995/0097B29C 48/18B29K 2023/06B29L 2007/00B29K 2081/00Y02E60/10B29K 2995/0007
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Claims

Abstract

A multi-functional battery separator comprises two or more active separator layers deposited from different polymer solutions to form a multilayered unitary structure comprising a free-standing film, a multiplex film on one side of a porous substrate, or separate films or multiplex films on opposite sides of a porous substrate. In a preferred embodiment, the cascade coating method is used to simultaneously deposit the active separator layers wet so that the physical, electrical and morphological changes associated with the polymer drying out process are avoided or minimized. The multi-functional separator is inexpensive to fabricate, exhibits enhanced ionic conductivity and ionic barrier properties, and eliminates gaps between individual layers in a separator stack that can contribute to battery failure.

Claims

exact text as granted — not AI-modified
1 . A method of producing a separator comprising:
 providing a PE polymer mixture, and   providing a PVA polymer mixture,   wherein the PE polymer mixture and the PVA polymer mixture are provided to form a unitary separator comprising a PE polymer layer and a PVA polymer layer, wherein the PE polymer layer resists oxidation and the PVA polymer layer resists dendrite formation.   
     
     
         2 . The method of  claim 1 , wherein the separator has a total thickness of less than 200 microns. 
     
     
         3 . The method of  claim 2 , further comprising providing 1 to 10 additional polymer mixtures, wherein the polymer mixtures are provided to form a separator comprising a PE polymer layer, a PVA polymer layer, and from 1 to 10 additional polymer layers. 
     
     
         4 . The method of  claim 1 , further comprising providing a porous substrate. 
     
     
         5 . The method of  claim 2 , wherein the PE polymer mixture and the PVA polymer mixture are provided on the porous substrate to form a unitary separator. 
     
     
         6 . The method of  claim 3 , wherein the PE polymer mixture and the PVA polymer mixture are provided on opposing sides of the porous substrate to form a unitary separator. 
     
     
         7 . The method of  claim 5 , wherein the porous substrate comprises a polyolefin material. 
     
     
         8 . The method of  claim 7 , wherein the porous substrate comprises polyethylene or polypropylene. 
     
     
         9 . The method of  claim 1 , wherein the PE polymer mixture and the PVA polymer mixture are each provided by coextrusion to form a unitary separator. 
     
     
         10 . The method of  claim 9 , wherein either of the PE polymer mixture is at least partially cured before being provided with the PVA polymer mixture, or the PVA polymer mixture is at least partially cured before being provided with the PE polymer mixture. 
     
     
         11 . A multi-functional separator comprising
 a porous substrate film, and   a plurality of active separator layers   wherein at least one of the active separator layers is deposited on the film.   
     
     
         12 . The multi-functional separator of  claim 11 , wherein a first active separator layer and a second active separator layer are deposited on opposite sides of the porous substrate film. 
     
     
         13 . An electrochemical cell comprising
 an electrolyte,   an anode,   a cathode, and   a multi-functional separator,   
       wherein the electrolyte is an alkaline electrolyte, the anode comprises zinc metal, and the multi-functional separator comprises:
 an oxidation-resistant separator layer deposited from a PE solution comprising a polyether polymer that can be linear or branched and can be unsubstituted or substituted; and 
 a dendrite-resistant separator layer deposited from a PVA solution comprising a cross-linking agent and a polyvinyl alcohol precursor polymer, which can be linear or branched and can be unsubstituted or substituted. 
 
     
     
         14 . The electrochemical cell of  claim 13 , wherein the alkaline electrolyte comprises an aqueous solution of a hydroxide of an alkali metal selected from the group consisting of potassium, sodium, lithium, rubidium, cesium, and mixtures thereof. 
     
     
         15 . The electrochemical cell of  claim 13 , wherein the cathode comprises an active material selected from the group consisting of silver oxide, nickel oxide, cobalt oxide, and manganese oxide. 
     
     
         16 . The electrochemical cell of  claim 13 , wherein the polyether polymer comprises polyethylene oxide or polypropylene oxide, or a copolymer or a mixture thereof. 
     
     
         17 . The electrochemical cell of  claim 13 , wherein the cross-linking agent is boric acid. 
     
     
         18 . The electrochemical cell of  claim 13 , wherein one or both of the PE solution and the PVA solution further comprise a powder of a metallic oxide selected from the group consisting of zirconium oxide, titanium oxide and aluminum oxide. 
     
     
         19 . The electrochemical cell of  claim 13 , wherein one or both of the PE solution and the PVA solution further comprise a titanate salt of an alkali metal selected from the group consisting of potassium, sodium, lithium, rubidium, cesium, and mixtures thereof. 
     
     
         20 . The electrochemical cell of  claim 13 , wherein one or both of the PE solution and the PVA solution further comprise a surfactant. 
     
     
         21 . The electrochemical cell of  claim 13 , wherein the PVA solution further comprises a plasticizer. 
     
     
         22 . The electrochemical cell of  claim 13 , wherein the PVA solution further comprises a conductivity enhancer consisting of a coploymer of polyvinyl alcohol and a hydroxyl-conducting polymer selected from the group consisting of polyacrylates, polylactones, polysulfonates, polycarboxylates, polysulfates, polysarconates, polyamides, and polyamidosulfonates. 
     
     
         23 . A multi-functional separator comprising at least three active separator layers, wherein the multi-functional separator has an ionic resistance of <10 Ω/cm 2 , electrical resistance of >10 kΩ/cm 2 , and a wet tensile strength of >0.1 lbf. 
     
     
         24 . The multi-functional separator of  claim 23 , wherein the ionic resistance is <0.5 Ω/cm2. 
     
     
         25 . The multi-functional separator of  claim 24 , wherein the least two of the three active separator layers comprise a polymeric material each individually selected from PVA and PSA, or combinations thereof. 
     
     
         26 . The multi-functional separator of  claim 25 , wherein the PSA comprises PSS. 
     
     
         27 . The multi-functional separator of  claim 26 , wherein the multi-functional separator comprises the layers PVA/V6/PSS; PVAN6/(PSS+PAA); V6/PVA/(PSS+PAA); PVMPSS+PAA(35%))/(PSS+PAA(35%)); (PSS+PAA(35%))/PVA/(PSS+PAA(35%)); or (PSS+PAA (35%))/(PVA(10%)+PSS (20% vs. PVA))/(PSS+PAA (35%)). 
     
     
         28 . The multi-functional separator of  claim 27 , wherein the multi-functional separator comprises the layers PVA/V6/(PSS+PAA); V6/PVA/(PSS+PAA); or (PSS+PAA(35%))/PVA/(PSS+PAA (35%)). 
     
     
         29 . The multi-functional separator of  claim 28 , wherein the separator thickness is <100 mm. 
     
     
         30 . The multi-functional separator of  claim 29 , wherein the separator thickness is <30 μm. 
     
     
         31 . The multi-functional separator of  claim 30 , wherein each layer in the separator is <10 μm. 
     
     
         32 . (canceled) 
     
     
         33 . The multi-functional separator of  claim 23 , wherein at least two layers of the separator comprise a polymeric material each individually selected from PVA, a quaternary ammonium polymer, or combinations thereof. 
     
     
         34 . A method of producing a separator comprising:
 providing a PSA polymer mixture, and   providing a PVA polymer mixture,   wherein the PSA polymer mixture and the PVA polymer mixture are provided to form a unitary separator comprising a PSA polymer layer and a PVA polymer layer, wherein the PSA polymer layer resists oxidation and the PVA polymer layer resists dendrite formation.   
     
     
         35 . The method of  claim 34 , wherein the separator has a total thickness of less than 100 microns. 
     
     
         36 . The method of  claim 34 , further comprising providing 1 to 10 additional polymer mixtures, wherein the polymer mixtures are provided to form a separator comprising a PSA polymer layer, a PVA polymer layer, and from 1 to 10 additional polymer layers. 
     
     
         37 . The method of  claim 36 , wherein the separator has an ionic resistance of <10 Ω/cm2, electrical resistance of >10 kΩ/cm 2 , and a wet tensile strength of >0.1 lbf. 
     
     
         38 . The method of  claim 37 , wherein the ionic resistance is <0.5 Ω/cm 2 .

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