Systems and methods for minimizing and preventing dendrite formation in electrochemical cells
Embodiments described herein relate to electrochemical cells with dendrite prevention mechanisms. In some aspects, an electrochemical cell can include an anode disposed on an anode current collector, a cathode disposed on a cathode current collector, the cathode having a first thickness at a proximal end of the cathode and a second thickness at a distal end of the cathode, the second thickness greater than the first thickness, a first separator disposed on the anode, a second separator disposed on the cathode, an interlayer disposed between the first separator and the second separator, the interlayer including electroactive material and having a proximal end and a distal end, and a power source electrically connected to the proximal end of the cathode and the proximal end of the interlayer, the power source configured to maintain a voltage difference between the cathode and the interlayer below a threshold value.
1 . An electrochemical cell, comprising:
a first electrode;
a second electrode;
a first separator disposed on the first electrode; and
a second separator disposed on the second electrode, the second separator including an electrically conductive material;
wherein the first electrode, the second electrode, the first separator, and the second separator are formed in a rolled structure, the second separator forming an outer surface of the rolled structure, a portion of the electrically conductive material exposed on the outer surface.
2 . The electrochemical cell of claim 1 , wherein the electrically conductive material is disposed on the second separator.
3 . The electrochemical cell of claim 1 , wherein the first electrode includes an anode and the second electrode includes a cathode.
4 . The electrochemical cell of claim 1 , wherein the electrically conductive material includes at least one of activated carbon, hard carbon, soft carbon, conductive carbon particles, carbon black, graphitic carbon, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbons including “buckyballs”, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene, graphene sheets or aggregates of graphene sheets, or materials comprising fullerenic fragments.
5 . The electrochemical cell of claim 1 , wherein the second separator extends beyond the first separator on the outer surface of the rolled structure by an extension distance.
6 . The electrochemical cell of claim 5 , wherein the extension distance is between about 100 pm and about 2 mm.
7 . The electrochemical cell of claim 1 , further comprising:
a casing configured to house the rolled structure.
8 . The electrochemical cell of claim 7 , wherein the exposed portion of the electrically conductive material contacts the casing.
9 . The electrochemical cell of claim 7 , further comprising a tab coupled to the electrically conductive material and extending to a region external to the casing.
10 . The electrochemical cell of claim 9 , wherein the tab includes an electrically conductive polymer.
11 . An electrochemical cell, comprising:
an anode current collector;
a first anode material disposed on a first side of the anode current collector;
a second anode material disposed on a second side of the anode current collector, the second side opposite the first side;
a first separator assembly disposed on the first anode material, the first separator assembly including a first electrically conductive interlayer disposed between a first separator and a second separator;
a second separator assembly disposed on the second anode material, the second separator assembly including a second electrically conductive interlayer disposed between a third separator and a fourth separator;
a cathode material disposed on the first separator; and
a cathode current collector coupled to the cathode material.
12 . The electrochemical cell of claim 11 , wherein at least one of the first separator, the second separator, the third separator, or the fourth separator includes at least one of polyvinylidene fluoride (PVDF), styrene-butadiene (SBR), carboxymethyl cellulose (CMC), polyethylene oxides (PEO), polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PF A), 162 polyacrylonitrile (PAN), poly (acrylic acid) PAA, Poly Olefin, polysulfone (PES), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polybenzimidazole (PBI), polyamide-imides (PAI), polyimide (PI), polyether ether ketone (PEEK), ultraviolet (UV) curable resin, urethane/epoxy acrylate, A1203, boehmite, MgO, Al(OH)3, or ZrO2.
13 . The electrochemical cell of claim 11 , wherein the first separator assembly extends beyond the second separator assembly by an extension distance.
14 . The electrochemical cell of claim 11 , wherein at least one of the first electrically conductive interlayer or the second electrically conductive interlayer includes at least one of activated carbon, hard carbon, soft carbon, conductive carbon particles, carbon black, graphitic carbon, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbons including “bucky balls”, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene, graphene sheets or aggregates of graphene sheets, or materials comprising fullerenic fragments.
15 . The electrochemical cell of claim 11 , wherein the cathode material includes at least one of LFP, LNO, or NMC.
16 . The electrochemical cell of claim 11 , wherein the second electrically conductive interlayer is electrically coupled to the first electrically conductive interlayer.
17 . The electrochemical cell of claim 11 , wherein the second electrically conductive interlayer is in physical contact with the first electrically conductive interlayer.
18 . The electrochemical cell of claim 11 , wherein at least one of the first electrically conductive interlayer or the second electrically conductive interlayer includes Li(ix)NMC and x is between 0 and 1.
19 . The electrochemical cell of claim 11 , wherein at least one of the first anode material or the second anode material includes at least one of graphite, lithium metal, or silicon.
20 . An electrochemical cell, comprising:
an anode;
a first separator assembly disposed on a first side of the anode, the first separator assembly including a first separator, second separator, and a first electrically conductive material, the first separator assembly having a first length;
a cathode disposed on the first separator assembly; and
a second separator assembly disposed on a second side of the anode, the second separator assembly including a third separator, a fourth separator, and a second electrically conductive material, the second separator assembly having a second length longer than the first length.
21 . The electrochemical cell of claim 20 , wherein the electrochemical cell is wound in a rolled configuration such that a leading edge of the second separator assembly extends beyond a leading edge of the first separator assembly.
22 . The electrochemical cell of claim 20 , wherein at least one of the first separator, the second separator, the third separator, or the fourth separator includes at least one of polyvinylidene fluoride (PVDF), styrene-butadiene (SBR), carboxymethyl cellulose (CMC), polyethylene oxides (PEO), polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PF A), polyacrylonitrile (PAN), poly (acrylic acid) PAA, Poly Olefin, polysulfone (PES), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polybenzimidazole (PBI), polyamide-imides (PAI), polyimide (PI), polyether ether ketone (PEEK), ultraviolet (UV) curable resin, urethane/epoxy acrylate, A1203, boehmite, MgO, Al(OH)3, or ZrO2.
23 . The electrochemical cell of claim 20 , wherein at least one of the first electrically conductive material or the second electrically conductive material includes at least one of activated carbon, hard carbon, soft carbon, conductive carbon particles, carbon black, graphitic carbon, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbons including “buckyballs”, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene, graphene sheets or aggregates of graphene sheets, or materials comprising fullerenic fragments.
24 . The electrochemical cell of claim 20 , wherein the first electrically conductive material is electrically coupled to the second electrically conductive material.
25 . The electrochemical cell of claim 20 , wherein the anode includes a first anode material disposed on a first side of an anode current collector and a second anode material disposed on a second side of the anode current collector, the second side opposite the first side.
26 . The electrochemical cell of claim 25 , wherein at least one of the first anode material or the second anode material includes at least one of graphite, lithium metal, or silicon.
27 . A method of forming an electrochemical cell, comprising:
rolling a cathode around a central axis;
rolling a first separator assembly around the central axis, such that the first separator assembly is disposed on the cathode, the first separator assembly including a first electrically conductive interlayer disposed between a first separator and a second separator;
rolling an anode around the central axis, such that the anode is disposed on the first separator assembly; and
rolling a second separator assembly around the central axis to form the electrochemical cell, such that the second separator assembly is disposed on the anode, the second separator assembly including a second electrically conductive interlayer disposed between a third separator and a fourth separator.
28 . The method of claim 27 , wherein the second separator assembly extends beyond the first separator assembly.
29 . The method of claim 27 , wherein a portion of the second electrically conductive interlayer is exposed on an outside surface of the electrochemical cell.
30 . The method of claim 27 , wherein at least one of the first electrically conductive interlayer or the second electrically conductive interlayer includes at least one of activated carbon, hard carbon, soft carbon, conductive carbon particles, carbon black, graphitic carbon, carbon fibers, carbon microfibers, vapor-grown carbon fibers (VGCF), fullerenic carbons including “buckyballs”, carbon nanotubes (CNTs), multiwall carbon nanotubes (MWNTs), single wall carbon nanotubes (SWNTs), graphene, graphene sheets or aggregates of graphene sheets, or materials comprising fullerenic fragments.