Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/665—Composites
  • H01M4/667—Composites in the form of layers, e.g. coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/058—Construction or manufacture
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/64—Carriers or collectors
  • H01M4/66—Selection of materials
  • H01M4/661—Metal or alloys, e.g. alloy coatings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present disclosure relates to improvements in the structural components and physical characteristics of lithium ion battery articles to accord lower resistance than within standard rechargeable battery types (such as high-power lithium ion battery types, as one example).
• Such structural modifications relate to thinner metal current collector structures that increase internal resistance levels of a battery cell and the concomitant decrease in internal cell resistance through modifications of electrode coatings as an accommodation in that respect.
• Battery articles and methods of use thereof including such improvements are also encompassed within this disclosure.
• the present technology relates to a battery with metalized film current collector having low internal resistance for use in connection with lowering internal resistance in lithium ion batteries.
• Rechargeable power cells such as, without limitation, lithium ion batteries
• Rechargeable power cells are prevalent around the world as an electricity source and are growing in importance within a myriad of products. From rechargeable power tools, to electronic cars, to the ubiquitous cellular telephone (and like tablets, hand-held computers, etc.), to lithium ion batteries (of different ion types) are utilized as the primary power source due to reliability, the above-noted rechargeability, and longevity of usage.
• With such widely utilized power sources comes certain problems, some of which have proven increasingly serious. Notably, safety issues have come to light wherein certain imperfections within such lithium batteries, whether due to initial manufacturing issues or time-related degradation problems, cause susceptibility to firing potentials during short circuit events.
• lithium batteries are currently made from six primary components, a cathode material, a cathode current collector (such as aluminum foil) on which the cathode material is coated, an anode material, an anode current collector (such as copper foil) on which the anode material is coated, a separator situated between each anode and cathode layer and typically made from a plastic material, and an electrolyte as a conductive organic solvent that saturates the other materials thereby providing a mechanism for the ions to conduct between the anode and cathode.
• a cathode current collector such as aluminum foil
• an anode material such as copper foil
• Such events may further be caused by, as noted above, internal defects including the presence of metallic particles within the battery, burrs on the current collector materials, thin spots or holes in the separator (whether included or caused during subsequent processing), misalignments of battery layers (leaving “openings” for unwanted conductivity to occur), external debris penetrating the battery (such as road debris impacting a moving vehicle), crushing and/or destabilizing of the cell itself (due to accidents, for instance), charging the cell in a confined space, and the like.
• internal defects including the presence of metallic particles within the battery, burrs on the current collector materials, thin spots or holes in the separator (whether included or caused during subsequent processing), misalignments of battery layers (leaving “openings” for unwanted conductivity to occur), external debris penetrating the battery (such as road debris impacting a moving vehicle), crushing and/or destabilizing of the cell itself (due to accidents, for instance), charging the cell in a confined space, and the like.
• these types of defects are known to cause
• Lithium batteries are particularly susceptible to problems in relation to short circuiting. Typical batteries have a propensity to exhibit increased discharge rates with high temperature exposures, leading to uncontrolled (runaway) flaring and firing on occasion, as noted above. Because of these possibilities, certain regulations have been put into effect to govern the actual utilization, storage, even transport of such battery articles. The ability to effectuate a proper protocol to prevent such runaway events related to short circuiting is of enormous importance, certainly. The problem has remained, however, as to how to actually corral such issues, particularly when component production is provided from myriad suppliers and from many different locations around the world.
• Electric aircraft for that matter, such as drones, air taxies, and the like, require very high-power levels for liftoff and landing, at least, with safety considerations.
• the same issues arise as it concerns the fast-charge capabilities of batteries within cellular phones, laptops, and other devices, as well, and certainly as it concerns the issues of safety due to possibly shorts and thermal runaway.
• the need for safety through thinner metal current collector structures is needed, but the state of the art in that respect overcompensates in a sense that power levels are compromised to too great an extent for such limited thin-film current collector considerations to be the solution on their own within the rechargeable power cell industry.
• the ability to reduce initial current collector structural weight certainly helps in some ways through a reduction of overall weight of a target cell.
• this limited modification does not allow for high-power enhancements as this structural modification accords the generation of high internal resistance in the target cell without any further compensation for a lack of power generation.
• the further ability to create power increases with concomitant weight reductions would be a further unexpected improvement.
• the only weight reductions for such power cells are related to safety through high internal resistance increases alone.
• the present disclosure provides such a highly desirable cure making lithium battery cells extremely safe, reliable, and viable for high-power devices within multiple markets.
• the present technology substantially fulfills this need.
• the battery with metalized film current collector having low internal resistance substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of lowering internal resistance in lithium ion batteries.
• the present technology provides an improved battery with metalized film current collector having low internal resistance, and overcomes the above-mentioned disadvantages and drawbacks of the prior art.
• the general purpose of the present technology which will be described subsequently in greater detail, is to provide a new and improved battery with metalized film current collector having low internal resistance and method which has all the advantages of the prior art mentioned heretofore and many novel features that result in a battery with metalized film current collector having low internal resistance which is not anticipated, rendered obvious, suggested, or even implied by the prior art, either alone or in any combination thereof.
• the present technology can include a lithium electrochemical energy generating and storage device comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, and at least one current collector in contact with at least one of the anode and the cathode.
• the current collector exhibits a resistivity greater than 0.005 Ohm/square.
• the electrochemical device exhibits a 2 C capacity greater than 70% of the capacity measured at 0.5 C.
• the current collector further comprising an insulating support layer coated with at least one conductive layer having a thickness that is less than 2 microns.
• the present technology can include a lithium electrochemical energy generating and storage device comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, and at least one current collector in contact with at least one of the anode and the cathode.
• the current collector can exhibit a resistivity greater than 0.005 Ohm/square.
• the at least one of the anode or cathode is structured to achieve low resistivity through the inclusion of at least one of the following: a) an electrode exhibiting a thickness less than 70 microns; b) an electrode coating containing greater than 6% by weight of a conductive additive; c) an electrode coating exhibiting a porosity greater than 35%; d) an electrode coating having multiple layers; and e) an electrode coating exhibiting an interspersed pattern of coating materials. At least one component of the pattern includes high energy, lower conductivity regions and at least one other component of the pattern includes higher conductivity regions. The conductivity can result from the presence of high conductive material content or high porosity material.
• the present technology can include a energy storage device comprising an anode and a cathode, a first separator interposed between the anode and the cathode, an electrolyte, a first current collector in contact with at least one of the anode and the cathode; a second current collector in contact with at least one of the anode and the cathode opposite to that of the first current collector, and a second separator in contact with the second current collector. At least one of the first current collector and the second current collector exhibits a resistivity greater than 0.005 Ohm/square.
• the device can exhibit a resistance less than of 15 mOhms. [016] In some or all embodiments, the device can exhibit an electrode areal energy density less than 4.0 mAh/cm 2 .
• the device can exhibit a product of capacity CAP and resistance R, wherein CAP x R is less than 40 mOhm-Ah.
• Some or all embodiments can further include a tab connected to the first current collector and configured for contact with an external contact.
• the first current collector and the second current collector each includes a metal film coated thereon.
• the metal film of the first current collector is a different metal to that of the metal film of the second current collector.
• the metal film of at least one of the first current collector and the second current collector can have a coating thickness of a total of less than 5 microns.
• the anode and the cathode can be porous exhibiting a porosity of at least 35%.
• the anode and the cathode can each include an electrode coating containing greater than 6% by weight of a conductive additive.
• the anode and the cathode can each have multiple layers including a top layer having higher conductivity than each successive lower layer.
• the anode and the cathode can each have multiple layers including a top layer exhibiting higher porosity than each successive lower layer.
• the cathode is a patterned electrode with a part of the cathode including first regions interspersed with second regions, wherein the first regions having a first energy or a first conductivity attribute, and the second regions having a second energy or a second conductivity attribute greater than the first regions thereby creating conductivity gradients
• the present technology can include an electrochemical energy generating and storage device (power cell, rechargeable battery, and the like) comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, and at least one current collector in contact with at least one of the anode and the cathode.
• the current collector exhibits a resistivity greater than 0.005 Ohm/square (preferably greater than 0.01, more preferably greater than 0.015, and most preferably at least 0.025 Ohms/square).
• the device exhibits a capacity CAP and resistance R, such that the product CAP x R is less than 40 mOhm-Ah (preferably less than 35, more preferably less than 30, still more preferably less than 25, and most preferably less than 20 mOhm-Ah).
• the electrochemical device exhibits a 2C capacity greater than 70% of the capacity measured at 0.2C (where 2C denotes a 30 minute discharge and 0.2C denotes a 5 hour discharge)(preferably greater than 75%, more preferably greater than 80%, still more preferably greater than 85%, and most preferably greater than 90%).
• the device may exhibit a resistance less than 15 mOhms (preferably less than 12, more preferably less than 10, still more preferably less than 8, even more preferably less than 6, and most preferably less than 4 mOhms).
• the cell may have both a low resistance target as well as a capacity target, with higher resistances allowed for lower capacity limitations.
• the capacity may be limited to be below 5 Ah, preferably below 20 Ah, more preferably below 40 Ah, even more preferably below 100 Ah, and most preferably below 200 Ah.
• Such an example might include a cell which is restricted in capacity to be below 10 Ah and a resistance below 10 mOhms.
• the device may exhibit an electrode areal energy density less than 4.0 mAh/cm 2 (preferably less than 3.5, more preferably less than 3,0, still more preferably less than 2.5, even more preferably less than 2.0, yet more preferably less than 1.5 and most preferably less than 1.0 mAh/cm 2 .
• the current collector exhibits a certain increased resistance while the entire device exhibits a certain decreased resistance, or, alternatively, a capacity and/or electrode areal energy density that counterintuitively meets certain limitations that have not been undertaken in the past.
• Such a difference between increased resistance with a current collector and differing physical characteristics of the device associated with the electrode structure(s) provides such novel measurements that accord higher power (for charge and discharge) for the entire device with a high resistance (low thickness and weight current collector) simultaneously.
• the present technology can provide electrode structures with nonconductive current collector components as polymer films or fabrics with metal layers on each of the top and bottom surfaces thereof wherein the anode and/or cathode (as electrodes with one contacting the current collector) provided with one or more of the following physical structures: a) a porous electrode exhibiting a porosity of at least 35% (more preferably at least 40%, still more preferably at least 45%, even more preferably at least 50%, and most preferably at least 55%); b) an electrode coating, wherein such a coating comprises a higher loading or higher conductivity additive within the electrode material, wherein the conductive additive may be graphite, carbon, or the like, and present at loadings of greater than 6% by weight thereof (preferably greater than 8%, more preferably greater than 10%, and most preferably greater than 12% by weight thereof), and/or wherein the high conductivity materials may also comprise metal particles and/or high aspect ratio conductive materials (such as nanotubes and/or carbon nanofibers);
• the patterned coatings may be laid down by various printing techniques which allow patterns of different materials to be achieved, as are well known in the art.
• Such multilayer structures may be produced by multiple passes, each depositing a single layer, or alternatively through coextrusion of multiple layers of materials through a single orifice or print head.
• the present technology can provide an initial thin metalized film current collector that drastically limits the delivery time of a current level applied to the target current collector surface through a probe tip (in order to controllably emulate the effect of an internal manufacturing defect, a dendrite, or an external event which causes an internal short within the subject battery) to less than 1 second, preferably less than 0.01 seconds, more preferably less than 1 millisecond, and most preferably, perhaps, even less than 100 microseconds, particularly for much larger currents.
• a metalized film current collector may be provided exhibiting a total thickness (of an entire metalized polymeric substrate) less than 20 microns, potentially preferably less than 15 microns, and potentially more preferably less than 10 microns, potentially even more preferably less than 8 microns, potentially still more preferably less than 6 microns, and potentially most preferably less than 4 microns, all with a resistivity measurement greater than 0.005 Ohm/ square (preferably greater than 0.01, more preferably greater than 0.015, and most preferably at least 0.025 Ohms/square).
• the thin component can be configured to allow for a short to react with the metal coat and in relation to the overall resistance levels to generate, with an excessively high temperature due to a current spike during such a short, a localized region of metal oxide that immediately prevents any further current movement therefrom.
• the resistance level remains high, however, as the thin structures exhibit such physical results.
• Some or all embodiments may include a temperature dependent metal (or metalized) material that either shrinks from a heat source during a short or easily degrades at the specific material location into a nonconductive material (such as aluminum oxide from the aluminum current collector, as one example)(as alluded to above in a different manner).
• a temperature dependent metal (or metalized) material that either shrinks from a heat source during a short or easily degrades at the specific material location into a nonconductive material (such as aluminum oxide from the aluminum current collector, as one example)(as alluded to above in a different manner).
• the current collector can be configured to become thermally weak, in stark contrast to the aluminum and copper current collectors that are used today, which are quite thermally stable to high temperatures.
• an alloy of a metal with a lower inherent melting temperature may degrade under lower shorting current densities, improving the safety advantages of the lithium-based energy device disclosed herein.
• the cell can be restricted in capacity to be below 10 Ah and a resistance below 10 mOhms.
• the current collector can include coating a layer of conductive material, for example copper or aluminum, on fibers or films that exhibit relatively high shrinkage rates at relatively low temperatures.
• the current collector can include thermoplastic films with melt temperatures below 250° C, or even 200° C, and can include as non-limiting examples polyethylene terephthalate, nylon, polyethylene or polypropylene.
• the current collector can include coating a layer of conductive material, for example copper or aluminum, as above, on fibers or films that can swell or dissolve in electrolyte when the materials are heated to relatively high temperatures compared to the operating temperatures of the cells, but low compared to the temperatures that might cause thermal runaway.
• the polymers configured to swell in lithium ion electrolytes can be polyvinylidene fluoride or poly acrylonitrile.
• the internal electrical fuse generating process can be coated onto a substrate a metal, for example aluminum, configured to oxidize under heat, at a total metal thickness that is much lower than usually used for lithium batteries.
• the thin aluminum current collector can include a coating thickness of a total of less than 5 microns, less than 2 microns, less than 1 micron, or less than 700 nm, or 500 nm.
• the coating can include a sufficient amount of or thickness of metal to provide sufficient conductivity to energize the cell.
• the thickness can be greater than 10 nm, preferably greater than 50 nm, or even greater than 100 nm, or greater than 200 nm.
• the areal density may be lower than 30 grams/square meter, preferably lower than 25, more preferably lower than 20, and most preferably lower than 15 grams/square meter.
• the break in conductive pathway can be accomplished by providing a current collector with limited conductivity that will degrade in the high current densities that surround a short, similar to the degradation found today in commercial fuses. This could be accomplished by providing a thin metalized film current collector with a resistivity of greater than 5 mOhm/square, or 10 mOhm/square, or potentially preferably greater than 20 mOhm/square, or, a potentially more preferred level of greater than 50 mOhm/square.
• the break in conductive pathway can be accomplished by providing a current collector that will oxidize into a non-conductive material at temperatures that are lower than aluminum, thus allowing the current collector to become inert in the area of the short before the separator degrades.
• the metal in the thin current collector layer capacity can be any metal that exhibits electrical conductivity, including, without limitation, gold, silver, vanadium, rubidium, iridium, indium, platinum, and others (basically, with a very thin current collector layer, the costs associated with such metal usage may be reduced drastically without sacrificing conductivity and yet still allowing for the protections from thermal runaway potentials during a short circuit or like event).
• layers of different metals may be employed or even discrete regions of metal deposited within or as separate layer components may be utilized.
• one side of the coated current collector substrate may include different metal species from the opposing side, and may also have different layer thicknesses in comparison, as well.
• an interface with the metal of the metalized substrate that allows for high current flow can be accomplished with a face-to-face contact, giving high surface area between the means of making electrical contact through the case and the metalized substrate.
• the surface area can be be higher than 1 square millimeter (10-12 square meters), or higher than 3 square millimeters, or even 5 square millimeters or more preferably 10 square millimeters.
• An even further object of the present technology is to provide a new and improved battery with metalized film current collector having low internal resistance that has a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such battery with metalized film current collector having low internal resistance economically available to the buying public.
• Still another obj ect of the present technology is to provide a new battery with metalized film current collector having low internal resistance that provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
• Fig. 1 is a Prior Art depiction of the architecture of a wound cell, such as an 18650 cell.
• Fig. 2 is a depiction of a Prior Art depiction of a side perspective view of the utilization of a thick coating electrode on a thin metalized film current collector.
• FIG. 3 is a depiction of a herein disclosed side perspective view of a thin coating electrode applied to a thin metalized film current collector.
• Fig. 4 is a top cross-sectional view of a jelly roll type lithium ion rechargeable battery including the electrode/metalized film current collector of Fig. 3.
• Fig. 5 is a depiction of a Prior Art depiction of a side perspective view of the utilization of a low porosity coating electrode on a thin metalized film current collector.
• Fig. 6 is a depiction of a herein disclosed side perspective view of a high porosity coating electrode applied to a thin metalized film current collector.
• Fig. 7 is a top cross-sectional view of a jelly roll type lithium ion rechargeable battery including the high porosity electrode/metalized film current collector of Fig. 6.
• Fig. 8 is a depiction of a herein disclosed side perspective view of a multi-layer electrode applied to a thin metalized film current collector.
• Fig. 9 is a top cross-sectional view of a jelly roll type lithium ion rechargeable battery including the multiday er electrode/metalized film current collector of Fig. 8.
• Fig. 10 is a depiction of a herein disclosed side perspective view of a patterned coating electrode applied to a thin metalized film current collector.
• Fig. 11 is a top cross-sectional view of a jelly roll type lithium ion rechargeable battery including the patterned electrode/metalized film current collector of Fig. 10.
• a distinct advantage of this disclosure is the ability through structural components to provide a mechanism to break the conductive pathway when an internal short occurs, stopping or greatly reducing the flow of current that may generate heat within the target battery cell.
• Another advantage is the ability to provide such a protective structural format within a lithium battery cell that also provides beneficial weight and cost improvements for the overall cell manufacture, transport and utilization.
• another advantage is the generation and retention of an internal fuse structure within a target battery cell until the need for activation thereof is necessitated.
• Another advantage is the provision of a low internal resistance high-power cell with a high resistance thin metal current collector for a fast charge and discharge capability.
• Still another advantage is the ability to utilize flammable organic electrolytes materials within a battery without any appreciable propensity for ignition thereof during a short circuit or like event.
• this inventive disclosure encompasses an electrochemical energy generating and storage device (power cell, rechargeable battery, and the like) comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, and at least one current collector in contact with at least one of the anode and the cathode; wherein the current collector exhibits a resistivity greater than 0.005 Ohm/square (preferably greater than 0.01, more preferably greater than 0.015, and most preferably at least 0.025 Ohms/square); wherein the device exhibits a capacity CAP and resistance R, such that the product CAP x R is less than 40 mOhm-Ah (preferably less than 35, more preferably less than 30, still more preferably less than 25, and most preferably less than 20 mOhm-Ah); and wherein the electrochemical device exhibits a 2C capacity greater than 70% of the capacity measured at 0.2C (where 2C denotes a 30 minute discharge and
• such a device may exhibit a resistance less than 15 mOhms (preferably less than 12, more preferably less than 10, still more preferably less than 8, even more preferably less than 6, and most preferably less than 4 mOhms).
• the cell may have both a low resistance target as well as a capacity target, with higher resistances allowed for lower capacity limitations.
• the capacity may be limited to be below 5 Ah, preferably below 20 Ah, more preferably below 40 Ah, even more preferably below 100 Ah, and most preferably below 200 Ah.
• Such an example might include a cell which is restricted in capacity to be below 10 Ah and a resistance below 10 mOhms.
• such a device may exhibit an electrode areal energy density less than 4.0 mAh/cm 2 (preferably less than 3.5, more preferably less than 3,0, still more preferably less than 2.5, even more preferably less than 2.0, yet more preferably less than 1.5 and most preferably less than 1.0 mAh/cm 2 .
• the current collector exhibits a certain increased resistance while the entire device exhibits a certain decreased resistance, or, alternatively, a capacity and/or electrode areal energy density that counterintuitively meets certain limitations that have not been undertaken in the past.
• Such a difference between increased resistance with a current collector and differing physical characteristics of the device associated with the electrode structure(s) provides such novel measurements that accord higher power (for charge and discharge) for the entire device with a high resistance (low thickness and weight current collector) simultaneously.
• Electrochemical power generating and storage devices are the ability to provide electrode structures with nonconductive current collector components as polymer films or fabrics with metal layers on each of the top and bottom surfaces thereof wherein the anode and/or cathode (as electrodes with one contacting the current collector) provided with one or more of the following physical structures: a) a porous electrode exhibiting a porosity of at least 35% (more preferably at least 40%, still more preferably at least 45%, even more preferably at least 50%, and most preferably at least 55%); b) an electrode coating, wherein such a coating comprises a higher loading or higher conductivity additive within the electrode material, wherein the conductive additive may be graphite, carbon, or the like, and present at loadings of greater than 6% by weight thereof (preferably greater than 8%, more preferably greater than 10%, and most preferably greater than 12% by weight thereof), and/or wherein the high conductivity materials may also comprise metal particles and/or high aspect ratio conductive materials (such
• Such patterned coatings may be laid down by various printing techniques which allow patterns of different materials to be achieved, as are well known in the art.
• Such multilayer structures may be produced by multiple passes, each depositing a single layer, or alternatively through coextrusion of multiple layers of materials through a single orifice or print head.
• an initial thin metalized film current collector that drastically limits the delivery time of a current level applied to the target current collector surface through a probe tip (in order to controllably emulate the effect of an internal manufacturing defect, a dendrite, or an external event which causes an internal short within the subject battery) to less than 1 second, preferably less than 0.01 seconds, more preferably less than 1 millisecond, and most preferably, perhaps, even less than 100 microseconds, particularly for much larger currents.
• a current would be limited to the internal voltage of the cell, which might be 5.0 V, or 4.5 V, or 4.2 V or even less, such as 4.0 V or 3.8 V, but with a minimum of 2.0 V.
• Such a metalized film current collector may be provided exhibiting a total thickness (of an entire metalized polymeric substrate) less than 20 microns, potentially preferably less than 15 microns, and potentially more preferably less than 10 microns, potentially even more preferably less than 8 microns, potentially still more preferably less than 6 microns, and potentially most preferably less than 4 microns, all with a resistivity measurement greater than 0.005 Ohm/square (preferably greater than 0.01, more preferably greater than 0.015, and most preferably at least 0.025 Ohms/square).
• Typical current collectors may exhibit these features but do so at far higher weight than those made with reinforcing polymeric substrates and without the inherent safety advantages of this presently disclosed variation.
• a copper foil at 10 microns thick may weight 90 grams/m 2 .
• a copperized foil may weight as little as 50 grams/ m 2 , or even as little as 30 gram / m 2 , or even less than 20 grams/ m 2 , all while delivering adequate electrical performance required for the cell to function (albeit with high internal resistance for the device itself).
• the very thin component also allows for a short to react with the metal coat and in relation to the overall resistance levels to generate, with an excessively high temperature due to a current spike during such a short, a localized region of metal oxide that immediately prevents any further current movement therefrom. The resistance level remains high, however, as the thin structures exhibit such physical results.
• a high resistance current collector is the provision of a temperature dependent metal (or metalized) material that either shrinks from a heat source during a short or easily degrades at the specific material location into a nonconductive material (such as aluminum oxide from the aluminum current collector, as one example) (as alluded to above in a different manner).
• a temperature dependent metal (or metalized) material that either shrinks from a heat source during a short or easily degrades at the specific material location into a nonconductive material (such as aluminum oxide from the aluminum current collector, as one example) (as alluded to above in a different manner).
• a nonconductive material such as aluminum oxide from the aluminum current collector, as one example
• Another alternative is to manufacture the current collector by coating a layer of conductive material, for example copper or aluminum, on fibers or films that exhibit relatively high shrinkage rates at relatively low temperatures.
• a layer of conductive material for example copper or aluminum
• examples of these include thermoplastic films with melt temperatures below 250° C, or even 200° C, and can include as non limiting examples polyethylene terephthalate, nylon, polyethylene or polypropylene.
• Another possible manner of accomplishing such a result is to manufacture a current collector by coating a layer of conductive material, for example copper or aluminum, as above, on fibers or films that can swell or dissolve in electrolyte when the materials are heated to relatively high temperatures compared to the operating temperatures of the cells, but low compared to the temperatures that might cause thermal runaway.
• Examples of such polymers that can swell in lithium ion electrolytes include poly vinyli dene fluoride and poly acrylonitrile, but there are others known to those with knowledge of the art.
• Yet another way to accomplish such an alternative internal electrical fuse generating process is to coat onto a substrate a metal, for example aluminum, that can oxidize under heat, at a total metal thickness that is much lower than usually used for lithium batteries.
• a metal for example aluminum
• a very thin aluminum current collector as used today may be 20 microns thick. A coating thickness of a total of less than 5 microns would break the circuit faster, and one less than 2 microns, or even less than 1 micron, or even less than 700 nm, or 500 nm would break the circuit even faster.
• Such a coating must also have enough metal to provide sufficient conductivity to energize the cell, and so should have a thickness greater than 10 nm, preferably greater than 50 nm, or even greater than 100 nm, or most preferably greater than 200 nm.
• Such use of thin conductive coatings, when combined with low thickness polymer substrates, will result in extremely low current collector areal density.
• the areal density may be lower than 30 grams/square meter, preferably lower than 25, more preferably lower than 20, and most preferably lower than 15 grams/square meter.
• another way to accomplish the break in conductive pathway is to provide a current collector with limited conductivity that will degrade in the high current densities that surround a short, similar to the degradation found today in commercial fuses.
• a thin metalized film current collector with a resistivity of greater than 5 mOhm/square, or 10 mOhm/square, or potentially preferably greater than 20 mOhm/square, or, a potentially more preferred level of greater than 50 mOhm/square.
• resistivities contribute, again, as alluded to above, a high internal resistance that may compromise, on its own, and without any compensation therefore, the power generating and delivery capabilities of the target cell.
• past modifications have simply modified current collector resistivities.
• resistivities may further be selected differently for batteries that are designed for high power, which might use a relatively low resistance compared to cells designed for lower power and higher energy, and/or which might use a relatively high resistance.
• Still another way to accomplish the break in conductive pathway is to provide a current collector that will oxidize into a non-conductive material at temperatures that are far lower than aluminum, thus allowing the current collector to become inert in the area of the short before the separator degrades. Certain alloys of aluminum will oxidize faster than aluminum itself, and these alloys would cause the conductive pathway to deteriorate faster or at a lower temperature.
• any type of metal in such a thin current collector layer capacity and that exhibits electrical conductivity including, without limitation, gold, silver, vanadium, rubidium, iridium, indium, platinum, and others (basically, with a very thin current collector layer, the costs associated with such metal usage may be reduced drastically without sacrificing conductivity and yet still allowing for the protections from thermal runaway potentials during a short circuit or like event).
• layers of different metals may be employed or even discrete regions of metal deposited within or as separate layer components may be utilized.
• one side of such a coated current collector substrate may include different metal species from the opposing side, and may also have different layer thicknesses in comparison, as well.
• Standard electrochemical cells include current collector structures, separators, and electrodes (anode and cathode) for electrical charge generation.
• the utilization of thin metalized films as current collectors has been limited to such standard structures (note the Japanese reference cited above) with typical electrode structures and separators, as well. These typical electrodes are of metal layers of significant thickness to provide overall stability to the cell (device) as well as to allow for high resistance levels internally as well.
• electrochemical devices it has been unexpectedly found that the utilization of certain unexplored electrode material coatings on metalized film current collectors. As such, it is now presented the different manners of providing such thin current collectors for safety (and high resistance levels) with such material coatings on such current collectors to provide effective resistance lowering structures in order to generate power quickly and to move such quickly as well to an outside device.
• Such advantages allow for low-weight, high safety level, and high power generating (charging and discharging) rechargeable electrochemical cells (lithium ion batteries, and the like, as non-limiting examples) that have heretofore been nonexistent within the pertinent industries.
• a thin metalized film current collector functions ostensibly as an internal fuse within a target energy storage device (e.g., lithium battery, capacitor, etc.).
• the electrode coatings applied thereto enhance the overall thin structure to a level that accords sufficient strength for structural stability within the target cell (device) but with the simultaneous capability of reducing the internal resistance of the overall cell in relation to the increased resistance of the thin metalized film current collector.
• the ion storage material can for example be a cathode or anode material for lithium ion batteries, as are well known in the art.
• Cathode materials may include lithium cobalt oxide LiCo0 2 , lithium iron phosphate LiFePCri, lithium manganese oxide LiMn 2 0 4 , lithium nickel manganese cobalt oxide LiNi x Mn y Co z 0 2 , lithium nickel cobalt aluminum oxide LiNi x CO y Al z 0 2 , or mixtures of the above or others as are known in the art.
• Anode materials may include graphite, lithium titanate Li 4 Ti 5 0i 2 , hard carbon, tin, silicon or mixtures thereof or others as are known in the art.
• the ion storage material could include those used in other energy storage devices, such as supercapacitors.
• the ion storage materials will include activated carbon, activated carbon fibers, carbide-derived carbon, carbon aerogel, graphite, graphene, graphene, and carbon nanotubes.
• the coating process can be any coating process that is generally known in the art. Knife- over-roll and slot die are commonly used coating processes for lithium ion batteries, but others may be used as well, including electroless plating.
• the ion storage material is in general mixed with other materials, including binders such as polyvinylidene fluoride or carboxymethyl cellulose, or other film-forming polymers.
• Other additives to the mixture include carbon black and other conducting additives.
• Connecting the means to make electrical contact with the metalized substrate can include commonly used methods, such as welding, taping, clamping, stapling, riveting, or other mechanical means. Because the metal of the metalized substrate can be very thin, in order to enable an interface that allows for high current flow, a face-to-face contact is generally required, giving high surface area between the means of making electrical contact through the case and the metalized substrate. To carry sufficient current, this surface area should be higher than 1 square millimeter (10 12 square meters) but may need to be higher than 3 square millimeters, or even 5 square millimeters or more preferably 10 square millimeters.
• the liquid electrolyte is typically a combination/mixture of a polar solvent and a lithium salt.
• polar solvents include, as noted above, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, but other polar solvents, including ionic liquids or even water may be used.
• Lithium salts commonly utilized within this industry include, without limitation, LiPF 6 , LiPF 4 , LiBF 4 , LiC10 and others.
• the electrolyte may also contain additives as are known in the art. In many cases, the electrolytes can be flammable, in which the safety features of the inventive metalized substrate current collectors can be advantageous preventing dangerous thermal runaway events which result in fire and damage both to the cell and external to the cell.
• Electrodes are typically produced through the application of coatings of electrode materials on current collectors.
• very high-power cells can be made by taking thick metal foils and coating them with thin coatings of electrodes, thus reducing the internal resistance of the cell to the point where power can be very quickly introduced and removed.
• the metalized film (thin) current collectors must exhibit a resistivity of greater than 0.005 Ohms/square (preferably greater than 0.01, more preferably greater than 0.015, and most preferably greater than 0.025, up to about 0.5).
• This current collector resistivity is thus also a characteristic of the target electrochemical cells in which such collectors are present, inasmuch as the low measurements are a starting point prior to any further accommodations and modifications of electrode coating applications.
• electrode coatings areal energy density (lower than 4 mAh/cm 2 , preferably lower than 3.5, more preferably lower than 3, still more preferably lower than 2.5, even more preferably lower than 2, further more preferably lower than 1.5, and most preferably less than 1), electrode coating thickness (preferably less than 70 microns, more preferably less than 60, still more preferably less than 50, even more preferably less than 40, and most preferably less than 30 microns), and/or electrode coating areal density less than 150 g/m 2 , preferably less than 120 g/m 2 , more preferably less than 100 g/m 2 .
• the application of electrode materials exhibiting such areal energy density, coating thickness, and/or coating areal density provides the unexpected results of generating a low internal cell resistance even when a high resistance ultra-thin current collector is present.
• This combination of ultra-thin current collector with very thin electrode coatings provides for electrochemical devices that exhibit the product of a capacity CAP and resistance R, CAP x R less than at most 40 mOhm-Ah (preferably at most 35, more preferably at most 30, still more preferably at most 25, and most preferably at most 20).
• Other ultra-thin current collector electrochemical cell devices require high resistance in relation to cell capacity. Contrary to such prior teachings, however, the utilization of the very thin electrode coatings accords an overall low resistance even with the high resistance ultra-thin current collectors present simultaneously.
• the disclosed thin electrode coatings on ultra-thin current collectors further results in an electrochemical device with total (overall) resistance measurement of less than 15 mOhms, preferably less than 12, more preferably less than 10, still more preferably less than 8, even more preferably less than 6, further more preferably less than 4, and most preferably less than 2.
• the capacity measured at 2C (30 minute discharge) > P * 0.5 C capacity (measured at 2 hour discharge) is wherein P is at least 90%, preferably at least 85%, more preferably at least 80%, even more preferably at least 75%, and most preferably at least 70%).
• another measurement result for such a novel high safety/low resistance (high power) electrochemical device is where 4 C (15-minute discharge) capacity > P * 0.5 C capacity, wherein P is the measure as above.
• Figure 2 shows a prior art structure of a thick coating electrode 11 applied to an ultra-thin current collector 12. Again, such a structure will exhibit a high resistivity internally within an electrochemical cell (lithium ion battery, as one non-limiting example).
• FIG. 4 thus shows the reduction in electrode coating thickness 15 as applied to an ultra-thin current collector 16.
• this counterintuitive operation compensates for the high resistivities exhibited by ultra-thin current collectors by imparting an internal low resistance within the target cell (as in Fig. 4).
• Fig. 4 thus shows the inclusion of such an ultra-thin aluminized film current collector 21 within a battery cell 20. Shown applied to the collector 21 is a thin cathode coating 22, a first separator 23 and an opposing thin anode coating 24. Further present are a second ultra-thin copperized film current collector 21a and a second separator 23a.
• aluminized film current collector 21 Connected to the aluminized film current collector 21 is an internal tab 25 for contact with an external contact (not illustrated) for electrical charge transfer.
• Such a cell 20 exhibits, as noted throughout, the safety levels associated with ultra-thin current collector presence and the high-power capabilities associated with the counterintuitive utilization and application of thin electrode coatings on such a collector surface.
• the measurements, concerns, and presentations above for the thin metalized film current collectors for Alternative 1 are also to be understood the same for the other Alternatives provided below.
• the current collectors described herein, in terms of structural and physical characteristics, at least, are to be considered the same for all such Alternatives (specifically to avoid restating the same paragraphs as above).
• the porosity of a lithium ion electrode material is desired to be low, as high porosity increases the amount of electrolyte used and increases the volume used for a given energy storage amount.
• typical battery practice today utilizes batteries with calendered electrode coatings (under very high pressures) exhibiting high coating densities (or, conversely, low coating porosities).
• typical high energy density cells using ultra- thin metalized current collector films include (and specifically target) the electrodes exhibiting high coating densities (low porosities).
• to target high porosity electrode coatings are, as above with thin electrode coatings, counterintuitive according to current practices.
• High porosity can be achieved, for example, by using a relatively large particle size material for the electrode coating. Such large particles create relatively large spaces between the particles, thereby increasing the porosity of such a solid coating structure. Lower porosity layers can be achieved by using smaller particle sizes which would achieve smaller interparticle spaces. Alternatively, a distribution of particle sizes that includes small particles would also achieve low density.
• Such high porosity structures may be measured in terms of tap density of such electrode materials and thus porosity calculated from such tap density measurements.
• the true density is the theoretical density of the materials, or for a mixture the volume normalized theoretical density.
• the tap density is obtained by mechanically tapping a graduated cylinder containing the sample until little further volume change is observed.
• the powder porosity is calculated by the following equation 1:
• Powder Porosity 1 - Tap Density / True Density Equation 1
• the bulk density of a coating is calculated as the weight/m 2 of coating divided by the volume/ m 2 .
• a coating that measures/exhibits 20 grams/ m 2 and is 20 microns thick has a bulk density of 1.0 g/cm 3 .
• the porosity of the coating is thus calculated by the following equation 2:
• FIG. 5 shows a prior art structure of a low porosity coating electrode 31 applied to an ultra- thin current collector 32. Again, such a structure will exhibit a high resistivity internally within an electrochemical cell (lithium ion battery, as one non-limiting example).
• Figure 6 thus shows the reduction in electrode coating thickness 35 as applied to an ultra-thin current collector 36. As noted above, this counterintuitive operation (within the state and standard of rechargeable electrochemical cells) compensates for the high resistivities exhibited by ultra-thin current collectors by imparting an internal low resistance within the target cell (as in Fig. 7).
• Fig. 7 thus shows the inclusion of such an ultra-thin aluminized film current collector 41 within a battery cell 40.
• a high porosity cathode coating 44 Shown applied to the collector 41 is a high porosity cathode coating 44, a first separator 43 and an opposing high porosity anode coating 42. Further present are a second ultra-thin copperized film current collector 41a and a second separator 43a. Connected to the aluminized film current collector 41 is an internal tab 45 for contact with an external contact (not illustrated) for electrical charge transfer.
• Such a cell 40 exhibits, as noted throughout, the safety levels associated with ultra-thin current collector presence and the high-power capabilities associated with the counterintuitive utilization and application of thin electrode coatings on such a collector surface.
• Conductive additives like carbon black or graphite, are essential components of lithium ion batteries due to the limited electrical conductivity of most electrode materials. However, because the conductive additives themselves do not store lithium and thus do not contribute to the energy storage capacity of the cells, their use is minimized to make room for the maximum amount of lithium storing materials such as NMC cathode materials. Modern lithium ion batteries are made with as little as 3% conductive additive in the coating, with 3-5% being quite common.
• the maximization of energy densities of typical, state of the art electrochemical cells combines the aforementioned low porosity electrode coating having low conductivity carbon content.
• Such a structure as alluded to above, maximizes the active conductive material (lithium ion structures, as examples) with in the coating.
• Another potential structural improvement for such electrochemical cells includes the utilization of multi-layered electrodes having differing gradients.
• Normal electrode materials are made from a single layer of electrode material coated on a current collector.
• the above-noted alternative of a single thin electrode coating provides the unexpectedly effective result of low internal resistance for a target cell, particularly in combination with (and coating application upon) a high resistivity, safety level imparting, ultra-thin current collector.
• the portion of the electrode materials that are far from the current collector will incur more resistance and ohmic heating than the portion of the electrode materials that is very near to the current collector.
• Such a structure will, likewise, impart a lower resistance internally within a target cell.
• This structural and physical result can be accomplished with a multilayer coating process, in which a first applied coating (being closest to the ultra-thin current collector surface) has lower porosity and/or lower conductive particle (carbon or graphite) content, and the porosity and/or conductive particle content are increased with subsequent layers (preferably, such porosity and conductive particle concentrations are increased with such subsequent layers simultaneously).
• the porosity increase can be achieved by reducing the pressure that is used in calendering processes for each successive layer.
• the conductive particle content can be increased by increasing the proportion of conductive particles included in the mixture.
• first layer 51B closest to the substrate (current collector 52), be very thin and highly conductive, followed by second layer (layer 2) 51 A, which is a low porosity, low carbon content layer, and a third layer (layer 3) 51 having a higher conductive particle content and even high porosity. More layers may be applied in like fashion with, as above, each subsequent layer having higher conductive particle content and higher porosity in stepwise fashion.
• a conductive “primer” layer is eliminated, and the lowest porosity, lowest conductive particle content layer is layer 1, with each subsequent layer increasing in porosity and/or conductive particle content.
• Fig. 9 thus shows the utilization of a multi-layer cathode coating 64 (represented by layers 1, 2, 3 of Fig. 8, 51, 51 A, 51B) applied to an ultra-thin aluminized film current collector 61 within a battery cell 60. Further present are a first separator 63 and an opposing multi-layer anode 64a (structured as for the cathode 64, but made from anodic materials, as well understood by the ordinarily skilled artisan). Such an anode is applied to a second ultra-thin copperized film current collector 61a and a second separator 63a. Connected to the aluminized film current collector 61 is an internal tab 65 for contact with an external contact (not illustrated) for electrical charge transfer. Such a cell 60 exhibits, as noted throughout, the safety levels associated with ultra-thin current collector presence and the high- power capabilities associated with the counterintuitive utilization and application of multi- layered, conductivity gradient electrode coatings on such a collector surface.
• Yet another method to achieve low internal resistance through electrode material modifications from those typically undertaken within the industry involves the application of an electrode material that may be utilized having certain patterns of conductive structures in contact with the target ultra-thin current collector surface.
• an electrode material that may be utilized having certain patterns of conductive structures in contact with the target ultra-thin current collector surface.
• there may be applied a first coating in discrete regions whether linear rows, linear columns, diagonal lines, spots, such as cubes, cylinders, or any other geometric three-dimensional shape, and the like
• a second coating in regions of the target ultra-thin current collector surface to which the first coating has not been applied.
• Such different coatings of electrode materials may then include any of the structural limitations and requirements noted above, including, without limitation, a first coating exhibiting high porosity, a second coating exhibit high conductivity, and any number of other coatings with differing physical results as to conductivity, and the like, as needed to provide a structure that, as above, compensates for the high resistivity levels imparted by the ultra-thin current collector itself.
• a first coating exhibiting high porosity
• a second coating exhibit high conductivity
• any number of other coatings with differing physical results as to conductivity, and the like as needed to provide a structure that, as above, compensates for the high resistivity levels imparted by the ultra-thin current collector itself.
• Fig. 10 shows an ultra-thin current collector 73 (again, providing higher safety levels for a target cell but concomitant lower resistivity as well) having applied thereto a first coating 71 providing in three-dimensional lines and having one type of electrode configuration (such as high energy density made by using lower conductive particle content, or lower porosity achieved through such means as smaller particle size materials), and a second coating 72 interspersed therewith in three-dimensional alternating lines to the first coating 71 having differing energy densities and/or higher conductive particle concentrations/content than the first coating 72.
• one type of electrode configuration such as high energy density made by using lower conductive particle content, or lower porosity achieved through such means as smaller particle size materials
• the higher porosity and/or higher conductive particle content areas can act as “superhighways” for ions and electrons, reducing the overall resistance internally of a target cell while retaining the higher energy density of the lower porosity, lower conductive particle content areas as needed for certain purposes, if desired.
• Fig. 11 thus shows the inclusion of such an ultra-thin aluminized film current collector 81 within a battery cell 80.
• Shown applied to the collector 81 is a patterned coated cathode 82, a first separator 83 and an opposing anode coating 82a.
• the patterned cathodes coating 82 includes regions as defined within Fig. 10, above (71 and 72).
• Such an anode is applied to a second ultra- thin copperized film current collector 84 and a second separator 83a.
• an internal tab 85 Connected to the aluminized film current collector 81 is an internal tab 85 for contact with an external contact (not illustrated) for electrical charge transfer.
• Such a cell 80 exhibits, as noted throughout, the safety levels associated with ultra-thin current collector presence and the high-power capabilities associated with the counterintuitive utilization and application of patterned electrode coatings on such a collector surface.

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