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 battery articles.
• the present technology relates to a battery connections and metalized film components in energy storage devices having internal fuses for use in connection with the utilization of thin metalized surface composite current collectors (aluminum and/or copper, as examples), high shrinkage rate materials, materials that become nonconductive upon exposure to high temperatures, and combinations thereof.
• Such improvements accord the ability to withstand certain imperfections (dendrites, unexpected electrical surges, etc.) within the target lithium battery through provision of ostensibly an internal fuse within the subject lithium batteries themselves that prevents undesirable high temperature results from short circuits.
• Battery articles and methods of use thereof including such improvements are also encompassed within this disclosure.
• Standard lithium ion batteries for example, are prone to certain phenomena related to short circuiting and have experienced high temperature occurrences and ultimate firing as a result. Structural concerns with battery components have been found to contribute to such problems.
• Lithium batteries remain prevalent around the world as an electricity source within a myriad of products. From rechargeable power tools, to electronic cars, to the ubiquitous cellular telephone (and like tablets, hand-held computers, etc.), lithium batteries (of different ion types) are utilized as the primary power source due to reliability, above-noted rechargeability, and longevity of usage. With such widely utilized power sources, however, 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. Basically, internal defects with conductive materials have been found to create undesirable high heat and, ultimately, fire, within such battery structures.
• 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.
• separator materials that are far more thermally stable than the polyethylene and polypropylene porous films that make up the base layer of such typical ceramic-coated separators.
• These low shrinkage, dimensionally stable separators exhibit shrinkage less than 5% when exposed to temperatures of at least 200° C (up to temperatures of 250,300, and even higher), far better than the high shrinkage rates exhibited by bare polymer films (roughly 40% shrinkage at 150° C), and of ceramic-coated films (more than 20% at 180° C) (such shrinkage measurement comparisons are provided in Prior Art FIG. 2).
• Such low shrinkage rate materials may change the mechanism of thermal degradation inside a target cell when a short occurs.
• Prior Art FIG. 3 shows a higher magnification of the end of one aluminum layer, showing that it ends in a layer of cracked grey matter.
• BEI which showed the resultant matter to actually be aluminum oxide, an insulating ceramic.
• the separator itself is thermally stable, the aluminum current collector will oxidize, effectively breaking the circuit (and stopping, as a result, any short circuit once the insulating aluminum oxide is formed). Once the circuit is broken, the current stops flowing and the heat is no longer generated, reversing the process that, with less stable separators, leads to thermal runaway.
• the tab ostensibly functions as a contact with such internal battery components and extends outside of the battery cell casing with contact points for such conductivity purposes.
• the tab must thus remain in place and not disengage from the current collector(s) and allow for unabated access to the external source without, again, dislodgement internally or disengagement therewith externally.
• the battery connections and metalized film components in energy storage devices having internal fuses substantially fulfills this need.
• the battery connections and metalized film components in energy storage devices having internal fuses according to the present technology 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 utilizing thin metalized surface composite current collectors (aluminum and/or copper, as examples), high shrinkage rate materials, materials that become nonconductive upon exposure to high temperatures, and combinations thereof.
• the present technology provides an improved battery connections and metalized film components in energy storage devices having internal fuses, 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 connections and metalized film components in energy storage devices having internal fuses and method which has all the advantages of the prior art mentioned heretofore and many novel features that result in a battery connections and metalized film components in energy storage devices having internal fuses which is not anticipated, rendered obvious, suggested, or even implied by the prior art, either alone or in any combination thereof.
• One aspect of the present technology can include a lithium battery cell that includes needed tab leads to allow for conductance from the internal portion thereof externally to power a subject device, which may be a non-trivial provision because of the thin nature of the electrodes, and potentially that the two sides of the electrode material may not be conductive with each other.
• tabs that exhibit sufficient safety levels in combination with the internal fuse characteristics noted above while simultaneously displaying pull strength to remain in place during utilization as well as complete coverage with the thin film metalized current collectors for such an electrical conductivity result.
• Such tabs are further provided with effective welds for the necessary contacts and at levels that exhibit surprising levels of amperage and temperature resistance to achieve the basic internal fuse result with the aforementioned sufficient conductance to an external device.
• the internal fuse developments of the present technology exhibiting extremely thin current collector structures, further allow for the potential for repetitive folds thereof within a single cell.
• Such a fold possibility provides the capability of connecting two sides of a current collector which might otherwise be electrically insulated by a polymer layer situated between the two conducting layers, without the need for excessive internal weight and/or battery volume requirements.
• the folded current collector retains the internal fuse characteristics while simultaneously permitting for such a power increase, potentially allowing for any number of power increases within any number of sized batteries without the need for the aforementioned excessive weight and volume requirements, creating new battery articles for different purposes with targeted high power levels and as high safety benefits as possible.
• the present technology can include an energy storage device comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, at least one metalized thin film current collector in contact with at least one of the anode and the cathode, and at least one tab attached to the at least one metalized thin film current collector.
• the at least one metalized thin film current collector has a polymer substrate layer having a top and bottom surface. A first metalized layer is placed on the polymer substrate top layer and a second metalized layer is attached to the polymer substrate bottom layer.
• the current collector exhibits weld divot therein such that at least a portion of the first and second metalized layer are in contact with one another.
• the present technology can include an energy storage device comprising an anode, a cathode, at least one separator present between the anode and the cathode, an electrolyte, at least one metalized thin film current collector in contact with at least one of the anode and the cathode, and at least one tab attached to the at least one metalized thin film current collector,.
• the at least one metalized thin film current collector has a polymer substrate layer having a top and bottom surface, wherein a first metalized layer is attached to the polymer substrate top layer and the tab is placed on the polymer substrate bottom layer the current collector exhibits weld divot therein such that at least a portion of the first metalized layer is in contact with the tab.
• the present technology can include a current collector tab system for utilization with an energy storage device including an anode and a cathode.
• the current collector tab system can include at least one current collector in contact with at least one of the anode and the cathode, at least one tab, and one or more weld divots.
• the current collector can be in contact with at least one of the anode and the cathode.
• the current collector can include a polymer substrate layer having a top and bottom surface. A first metalized layer can be attached to the polymer substrate top layer and a second metalized layer can be attached to the polymer substrate bottom layer.
• the tab can be attached to the polymer substrate top surface or the polymer substrate bottom surface.
• the weld divots can be exhibited on the current collector such that the tab is in contact with at least a portion of the first metalized layer or a portion of the second metalized layer, respectively.
• the weld divots can be configured to move the polymer substrate layer so that the first metalized layer and the second metalized layer are in contact.
• the present technology can include a process to produce a lithium ion battery comprising the steps of: a) providing an electrode having at least one metalized substrate with a coating of an ion storage material; b) providing a counterelectrode; c) layering the electrode and counterelectrode opposite each other with a separator component interposed between the electrode and the counterelectrode; d) providing a package material including an electrical contact component, wherein the contact includes a portion present internally within the package material and a portion present external to the package material; e) electrically connecting the electrical contact with the metalized substrate; f) introducing at least one liquid electrolyte with ions internally within the package material; and g) sealing the package material.
• the electrically connecting in step e) comprises a process whereby at least one metal layer of the metalized substrate is pressed through the polymer substrate of the metalized substrate to make electrical connection with resistance less than 1 ohm with the electrical contact.
• the present technology can include a method of producing current collection tab of a lithium ion battery. The method can include the steps of attaching a first metalized layer to a top layer of a polymer substrate of a current collector, and attaching a second metalized layer to a bottom layer of the polymer substrate. Contacting the current collector with at least one of anode and a cathode. Welding a portion of a tab to one of the first metalized layer and the second metalized layer so that a weld divot is formed contacting the tab to the first metalized layer and the second metalized layer, respectively.
• Some or all embodiments of the present technology can include at least one electrical connection tab attached through the weld divot to the metalized layer of the current collector.
• the weld divot can be associated with one of the anode and the cathode.
• the tab can be electrically connected through the weld divot to the anode or the cathode.
• the present technology can include reinforcements provided over the welds.
• the metalized film includes up to 25 layers thereof.
• the tab can be multiple tabs present up to 25.
• At least some of the metal layers are extruded through the adjacent current collectors to contact metalized layers of other current collectors that are otherwise not in face-to-face contact with the extruded metal layers.
• the weld divot can be multiple divots which exhibit a pattern that is fully populated, sparsely populated, partial grid staggered or partial grid aligned.
• the weld divot can include a divot shape of linear, a truncated pyramid, rounded pyramid or spherical.
• the polymer substrate layer can include a multi-layered metalized film structure with a polymer substrate in-between each individual metalized film, and a bottom-most metalized film of the multi-layered metalized film structure being the second metalized layer.
• the multi-layered metalized film structure can be configured to be manipulated through the weld divot to connect the multi-layered metalized film structure together at a weld interface.
• the weld divot can be configured to generate a graduated contour surrounding the weld divot to facilitate a full weld pressure application through the multi-layered metalized film structure.
• the graduated contour of the weld divot can include a raised peripheral edge at a top edge of the weld divot.
• An even further object of the present technology is to provide a new and improved battery connections and metalized film components in energy storage devices having internal fuses 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 connections and metalized film components in energy storage devices having internal fuses economically available to the buying public.
• Still another obj ect of the present technology is to provide a new battery connections and metalized film components in energy storage devices having internal fuses 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.
• Even still another obj ect of the present technology is to provide a battery connections and metalized film components in energy storage devices having internal fuses for utilizing thin metalized surface composite current collectors (aluminum and/or copper, as examples), high shrinkage rate materials, materials that become nonconductive upon exposure to high temperatures, and combinations thereof.
• thin metalized surface composite current collectors aluminum and/or copper, as examples
• high shrinkage rate materials materials that become nonconductive upon exposure to high temperatures, and combinations thereof.
• FIG. 1 is a Prior Art depiction of the architecture of a wound cell, such as an 18650 cell.
• FIG. 2 is a Prior Art depiction of the shrinkage as a function of temperature as measured by Dynamic Mechanical Analysis of several lithium ion battery separators, as measured according to NASA/TM-2010-216099 “Battery Separator Characterization and Evaluation Procedures for NASA's Advanced Lithium Ion Batteries”, which is incorporated herein by reference, section 3.5. Included are first generation separators (Celgard PP, Celgard tri -layer), 2 nd generation separators (ceramic PE) and 3 generation separators (Silver, Gold, Silver AR).
• FIG. 3 is a Prior Art depiction of a scanning electron micrograph (SEM) of the cross section of a pouch cell that has undergone a nail penetration test. The layers are aluminum and copper as mapped by BEI (backscattered electron imaging). The nail is vertical on the left side. In each case, the aluminum layer has retreated from the nail, leaving behind a “skin” of aluminum oxide, an insulator.
• SEM scanning electron micrograph
• FIG. 3A is a Prior Art depiction of a zoom in on one of the layers from the image shown in Fig 3. It shows a close up of the aluminum oxide layer, and also reveals that the separator had not shrunk at all and was still separating the electrodes to the very edge.
• FIG. 4 is a depiction of the metalized film used in the current invention, where the thin layer of conductive material is on the outside, and the center substrate is a layer that is thermally unstable under the temperatures required for thermal runaway.
• This substrate can be a melting layer, a shrinking layer, a dissolving layer, an oxidizing layer, or other layer that will undergo a thermal instability at a temperature between 100° C and 500° C.
• FIG. 5 is a Prior Art depiction of a thick aluminum current collector, generally between
• FIG. 5 A is a depiction of the metalized film used in the current invention, showing a 14- micron thick substrate with 1 micron of aluminum on each side.
• the inventive current collector it is not capable of carrying the high currents associated with a short circuit, while the thick current art is and does.
• FIGS. 6 and 6A show images of comparative examples 1-2, each after having been touched by the tip of a hot soldering iron.
• the comparative examples do not change after touching with a hot soldering iron.
• FIGS. 7, 7 A, and 7B show images of examples 1-3, each after having been touched by the tip of a hot soldering iron.
• the examples 1-3 all exhibit shrinkage as described in this disclosure for substrates to be metalized.
• FIGS. 8, 8 A, and 8B show images of examples 4-6, each after having been touched by the tip of a hot soldering iron.
• the example 4 exhibits shrinkage as described in this disclosure for substrates to be metalized.
• Example 5 has a fiber that will dissolve under heat in lithium ion electrolytes.
• Example 6 is an example of a thermally stable substrate that would require a thin conductive layer to function as the current invention.
• FIGS. 9, 9 A, and 9B are SEMs at different magnifications in cross section and one showing the metalized surface of one possible embodiment of one current collector as now disclosed as described in Example 9. The metal is clearly far thinner than the original substrate, which was 20 microns thick.
• FIGS. 10 and 10a are optical micrographs of a Comparative Examples 3 and 4 after shorting, showing ablation of the area around the short but no hole.
• FIGS. 11 and 11a are optical micrographs of two areas of Example 14 after shorting, showing clear holes in the material caused by the high current density of the short.
• FIG. 12 shows a depiction of the size and shape of a test strip for testing the current carrying capacity of the current collector utilized for Examples noted below.
• FIG. 13 depicts a side perspective view of a single layer current collector with welded tab as one potentially preferred embodiment.
• FIG. 14 depicts a side perspective view of a single layer current collector with taped tab as another potentially preferred embodiment.
• FIG. 15 depicts a side perspective view of a single layer current collector with stapled tab as another potentially preferred embodiment.
• FIG. 16 depicts a side perspective view of a single layer current collector with a single rounded fold therein and a taped tab as another potentially preferred embodiment.
• FIG. 17 depicts a side perspective view of a single layer current collector with a double rounded fold therein and a taped tab as another potentially preferred embodiment.
• FIG. 18 depicts a side perspective view of a single layer current collector with two parallel welded tabs as another potentially preferred embodiment.
• FIG. 19 depicts a side perspective view of a single layer current collector with a single folded welded tab as another potentially preferred embodiment.
• FIG. 20 depicts a side perspective view of a single layer current collector with a double rounded fold therein and a welded tab as another potentially preferred embodiment.
• FIG. 21 depicts a side perspective view of a plurality of single layer current collectors each with a double rounded fold therein and a welded tab as another potentially preferred embodiment.
• FIG. 22 depicts a side perspective view of a plurality of single layer current collectors each with a double rounded fold therein and two opposing welded tabs as another potentially preferred embodiment.
• FIG. 23 depicts a side perspective view of a plurality of single layer current collectors in contact with a multiple Z-folded clamped tab as another potentially preferred embodiment.
• FIG. 24 depicts a front perspective view of a composite current collector having a polymer substrate with two separate layers of metalized film and a single weld present.
• FIG. 25 depicts a side view of a composite current collector having a polymer substrate and two separate layers of metalized film with a well-connected tab attached thereto.
• FIG. 26 is a high-magnification electron microscope cross-sectional view of a 100- micron length perspective of a welded current collector/polymer substrate composite (as in FIG. 25).
• FIG. 26A is a 50-micron length perspective cross-sectional view of the composite of FIG. 26.
• FIG. 27 depicts a side perspective view of a composite current collector having a polymer substrate and two separate layers of metalized film with a welded tab attached thereto.
• FIG. 27A is a high-magnification electron microscope cross-sectional view of a 500- micron portion of the interface between the metalized film, polymer substrate, and tab as shown at the weld location in FIG. 27.
• FIG. 27B is a 100-micron portion of the interface of FIG. 27A.
• FIG. 28 depicts a side perspective view of a composite current collector having a polymer substrate and multiple layers of metalized film with a welded tab attached thereto.
• FIG. 28A is a high-magnification electron microscope cross-sectional view of a 500- micron length perspective of the welded multi-layered metalized film/polymer substrate composite as shown in FIG. 28.
• FIG. 28B is a 200-micron length perspective view of the composite of FIG. 28 A.
• FIG. 29 depicts a side exploded perspective view of multi-layer of a metalized film current collector welded to a tab.
• FIG. 30 depicts a transparent side perspective view of a rigid plastic enclosure battery including a metalized film current collector and welded tab composite.
• FIG. 31 depicts a side transparent view of a cylindrical battery with a jelly roll composite current collector with a welded tab.
• FIG. 32 depicts a side perspective transparent view of a pouch enclosure battery including a metalized film current collector and welded tab composite.
• FIG. 33 depicts a front perspective view of a multi-layer battery composite with multilayers of metalized film current collectors and welded tabs.
• FIG. 33A is a different side perspective view of the battery composite of FIG. 33.
• FIG. 34 depicts different potential embodiments of alternative weld structures in association with the metalized film current collectors and tabs herein.
• FIG. 35 depicts a possible embodiment configuration of a fully populated weld grid structure.
• FIG. 35 A depicts a possible embodiment configuration of a sparsely populated weld grid structure.
• FIG. 36 depicts a possible embodiment configuration of a partial staggered weld grid structure.
• FIG. 37 depicts a possible embodiment configuration of a partial aligned weld grid structure.
• FIG. 38 depicts a side perspective view of a current collector and tab battery composite having a top-side weld present.
• FIG. 39 depicts a side perspective view of a current collector and tab battery composite having a film-side weld present.
• FIG. 40 depicts a side perspective view of a single folded welded tab and current collector composite.
• FIG. 41 depicts a partially exploded side perspective view of a multi-layer current collector and multi-tab composite.
• FIG. 42 depicts a side perspective view of a composite of an electrode and welded tab including a separating fuse structure.
• FIG. 43 depicts a side perspective view of a portion of a current collector/electrode/tab composite with tape for attachment.
• FIG. 44 depicts a side perspective view of a battery composite having multi-layer current collectors and electrodes and a wound tape connection for a welded tab.
• FIG. 45 depicts a side perspective view of a battery composite having multi-layer current collectors and electrodes and a clamped tape connection for a welded tab.
• 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 lower weight battery through the utilization of a thin film base current collector that prevents thermal runaway during a short circuit or like event.
• 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.
• Another distinct advantage is the ability to provide a sufficient conducting tab component welded, or otherwise in contact with, the internal fuse current collector, particularly in contact with both the upper surface and lower surface thereof simultaneously. Yet another advantage is the ability to create folds within the thin current collector components disclosed herein in order to allow for cumulative power generation in series of multiple current conductance internal structures to provide robust on-demand battery results without needing excessive weight or volume measurements.
• this inventive disclosure encompasses an energy storage device comprising an anode, a cathode, at least one polymeric or fabric separator present between said anode and said cathode, an electrolyte, and at least one current collector in contact with at least one of said anode and said cathode; wherein either of said anode or said cathode are interposed between at least a portion of said current collector and said separator, wherein said current collector comprises a conductive material coated on a polymeric material substrate, and wherein said current collector stops conducting at the point of contact of an exposed short circuit at the operating voltage of said energy storage device, wherein said voltage is at least 2.0 volts.
• One example would be a current density at the point of contact of 0.1 amperes/mm 2 with a tip size of 1 mm 2 or less.
• the required threshold current density may be higher, and the cell may only stop conducting at a current density of at least 0.3 amperes/mm 2 , such as at least 0.6 amperes/mm 2 , or even at least 1.0 amperes/mm 2 .
• Such a coated polymeric material substrate should also exhibit an overall thickness of at most 25 microns, as described in greater detail below.
• such a thin film current collector battery article may also be provided with at least one tab contacted with a base thin film collector through between 2 and 50 welds (which may be uniformly spaced and sized) leading along the length of said current collector, wherein said at least one tab is laid upon said thin film such that said at least one tab has an exposed top surface or a bottom surface in contact with a covered surface of said thin film current collector, wherein said welds exhibit placement of conductive material passing through said tab from its exposed top surface to said covered surface of said thin film current collector.
• welds exhibit placement of conductive material passing through said tab from its exposed top surface to said covered surface of said thin film current collector.
• a larger current such as 5 amperes, or 10 amperes, or even 15 amperes, may be connected for a very short time period [for example, less than a second, alternatively less than 0.1 seconds, or even less than 1 millisecond (0.001 seconds)].
• the delivery time for such a current is sufficiently short such that the total energy delivered is very small and not enough to generate enough heat to cause a thermal runaway event within the target battery cell.
• a short within a conventional architecture cell has been known to generate 10 amperes for 30 seconds across 4.2 volts, a result that has delivered 1200 joules of energy to a small local region within such a battery.
• This resultant measurement can increase the temperature of a 1-gram section of the subj ect battery by about 300° C, a temperature high enough to not only melt the conventional separator material present therein, but also drive the entire cell into a runaway thermal situation (which, as noted above, may cause the aforementioned compromise of the electrolyte materials present therein and potential destruction of not only the subject battery but the device/implement within which it is present and the surrounding environment as well.
• thermal runaway and the potential disaster associated therewith
• the reduction of short circuit residence time within a current collector to 1 millisecond or less can then subsequently reduce the amount of delivered energy to as low as 0.04 joules (as opposed to 1200 joules, as noted above, leading to excessive, 300° Celsius or greater, for example, within a 1-gram local region of the subj ect battery).
• Such a low level would thus only generate a temperature increase of 0.01° C within such an 1-gram local region of battery, thus preventing thermal runaway within the target cell and thus overall battery.
• the battery a 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 subj ect 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.
• Standard current collectors are provided are conductive metal structures, such as aluminum and/or copper panels of thicknesses that are thought to provide the necessary strength to survive the manufacturing process.
• the strength of these metals necessitates a thickness that is far in excess of the electrical needs of the cell.
• the electrical needs of the cell dictate a metal thickness on the order of 500nm of Aluminum, while the thinnest solid foil aluminum that can survive the manufacturing process is around 10 pm.
• the current pathway (charge direction) of a standard current collector remains fairly static both before and during a short circuit event, basically exhibiting the same potential movement of electric charge as expected with movement from cathode to anode and then horizontally along the current collector in a specific direction.
• this current pathway fails to prevent or at least curtail or delay such charge movement, allowing, in other words, for rapid discharge in runaway fashion throughout the battery itself. Coupled with the high temperature associated with such rapid discharge leads to the catastrophic issues (fires, explosions, etc.) noted above.
• the utilization of a current collector of the instant disclosure results in an extremely high current density measurement (due to the reduced thickness of the conductive element) and prevention of charge movement (e.g., no charge direction) in the event of a short circuit.
• the current density increases to such a degree that the material is unable to remain intact and fails by vaporizing.
• the total amount of energy necessary to cause this failure of the conductor is low as discussed above and results in very low temperatures generated from the event.
• the conductive material oxidizes instantly at the charge point thereon, leaving, for example, aluminum or cupric oxide, both nonconductive materials.
• the short circuit charge appears to dissipate as there is no direction available for movement thereof.
• the lack of further current throughout the body of the energy storage device mutes such an undesirable event to such a degree that the short is completely contained, no runaway current or high temperature result occurs thereafter, and, perhaps most importantly, the current collector remains viable for its initial and protective purposes as the localized nonconductive material then present does not cause any appreciable reduction in current flow when the energy storage device (battery, etc.) operates as intended.
• the relatively small area of nonconductive material generation leaves significant surface area, etc., on the current collector, for further utilization without any need for repair, replacement, or other remedial action.
• Such advantages are permitted in relation to such a novel resultant current collector that may be provided, with similar end results, through a number of different alternatives.
• a current collector as described herein functions ostensibly as an internal fuse within a target energy storage device (e.g., lithium battery, capacitor, etc.).
• a target energy storage device e.g., lithium battery, capacitor, etc.
• the total thickness of the entire metalized (coated) polymeric substrate of the current collector is less than 20 microns, potentially preferably less than 15 microns, and potentially more preferably less than 10 microns, all with a resistance measurement of less than 1 ohm/square potentially preferably less than 0.1 ohms/square, and potentially more preferably less than 50 milli-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. For example, a copper foil at 10 microns thick may weight 90 grams/m 2 .
• a copperized foil may weigh 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.
• 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.
• Another possible alternative for such a novel 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 and 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 and as alluded to above in a different manner).
• a nonconductive material such as aluminum oxide from the aluminum current collector, as one example and as alluded to above in a different manner.
• the current collector becomes 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-
• 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 polyvinylidene 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 would break the circuit even faster.
• 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 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. These measurements could be on one side, or on both sides of a material coated on both sides.
• current collectors of different 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 layer capacity and that exhibits electrical conductivity including, without limitation, gold, silver, vanadium, rubidium, iridium, indium, platinum, and others (basically, with a very thin 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.
• a coated current collector includes two conductive coated sides, ostensibly allowing for conductivity from the coating on one side to the coating on the other side. Such a result is not possible for a non- coated polymer film, for instance.
• a two-sided conductivity throughput can be achieved by, as one non-limiting example, a nonwoven including a certain percentage of conducting fibers, or a nonwoven loaded with conductive materials, or a nonwoven made from a conductive material (such as carbon fibers or metal fibers), or, as noted above, a nonwoven containing fibers coated with a conductive material (such as fibers with a metal coating on the surface).
• novel thin current collector material exhibiting top to bottom conductivity may be a film that has been made conductive, such as through the utilization of an inherently conductive material (such as, for example, conductive polymers such as poly acetylene, polyaniline, or polyvinylpyrrolidone), or via loading with a conductive material (such as graphite or graphene or metal particles or fibers) during or after film manufacture.
• an inherently conductive material such as, for example, conductive polymers such as poly acetylene, polyaniline, or polyvinylpyrrolidone
• a conductive material such as graphite or graphene or metal particles or fibers
• another possible two-sided thin current collector material is a polymer substrate having small perforated holes with sides coated with metal (aluminum or copper) during the metallization process. Such a conductivity result from one side to the other side would not need to be as conductive as the conductive coatings.
• such alternative configurations garnering ostensibly the same current collector results and physical properties include a) wherein the total thickness of the coated polymeric substrate is less than 20 microns with resistance less than 1 ohm/square, b) the collector comprising a conductive material coated on a substrate comprising polymeric material, wherein the polymeric material exhibits heat shrinkage at 225° C of at least 5%, c) wherein the collector metalized polymeric material swells in the electrolyte of the battery, such swelling increasing as the polymeric material is heated, d) wherein the collector conductive material total thickness is less than 5 microns when applied to a polymeric substrate, e) wherein the conductivity of the current collector is between 10 mOhm/square and 1 ohm/square, and f) wherein the metalized polymeric substrate of the collector exhibits at most 60% porosity.
• the above example can also be made thinner, a total thickness of 11 microns compared to 20 microns, for example, again reducing the volume of the cell, thereby effectively increasing the energy density.
• a current collector oflessthan 15 microns, preferably lessthan 12, more preferably lessthan lO, and most preferably less than 8 microns total thickness can be made and utilized for such a purpose and function.
• a thin coating can be made with less than 1 ohm/square, or less than 0.5 ohms/square, or even less than 0.1 ohms/square, or less than 0.05 ohms/square.
• the thickness of these conductive coatings could be less than 5 microns, preferably than3 microns, more preferably less than 2 microns, potentially most preferably even less thanl micron. It is extremely counterintuitive, when standard materials of general use in the market contain 10 microns or more of metal, that suitable performance could be obtained using much less metal.
• these conductive layers can be made by multiple layers.
• a layer of aluminum may be a base layer, coated by a thin layer of copper.
• the bulk conductivity can be provided by the aluminum, which is light, in expensive and can easily be deposited by vapor phase deposition techniques.
• the copper can provide additional conductivity and passivation to the anode, while not adding significant additional cost and weight. This example is given merely to illustrate and experts in the art could provide many other multilayer conductive structures, any of which are excellent examples of this invention.
• These thin metal coatings will in general result in higher resistance than in an aluminum or copper current collector of normal practice, providing a distinguishing feature of this invention in comparison.
• Such novel suitable current collectors can be made at greater than 10 mOhm/square, preferably greater than 20 mOhm/square, more preferably greater than 50 mOhm/square, and potentially most preferably even greater than 100 mOhm/square.
• cells made with the thermally weak current collectors described above could be made even more safe if the separator has a high thermal stability, such as potentially exhibiting low shrinkage at high temperatures, including less than 5% shrinkage after exposure to a temperature of 200° C for 1 hour, preferably after an exposure of 250° C for one hour, and potentially more preferably after an exposure to a temperature of 300° C for one hour.
• Existing separators are made from polyethylene with a melt temperature of 138° C and from polypropylene with a melt temperature of 164° C. These materials show shrinkage of >50% at 150° C, as shown in Figure 2; such a result is far too high for utilization with a thin current collector as now described herein.
• any of these metalized substrates it is desirable to have a low thickness to facilitate increase the energy density of the cell. Any means can be used to obtain such thickness, including calendering, compressing, hot pressing, or even ablating material from the surface in a way that reduces total thickness. These thickness-reducing processes could be done before or after metallization. Thus, it is desirable to have a total thickness of the metalized substrate of less than 25 microns, preferably less than 20 microns, more preferably less than 16 microns, and potentially most preferably less than 14 microns. Commercial polyester films have been realized with thicknesses of at most 3 microns, and even lower at 1.2 microns.
• the density of the polymer used in the substrate material could be less than 1.4 g/cm 3 , preferably less than 1.2 g/cm 3 , and potentially more preferably less than 1.0 g/cm 3 .
• the areal density of the substrate material could be less than 20 g/m 2 , preferably less than 16 g/m 2 , and potentially most preferably less than 14 g/m 2 .
• the areal density of the metal coated polymer substrate material could be less than 40 g/m 2 , preferably less than 30 g/m 2 , more preferably less than 25 g/m 2 , and potentially most preferably less than 20 g/m 2 .
• High strength is required to enable the materials to be processed at high speeds into batteries. This can be achieved by the use of elongated polymers, either from drawn fibers or from uniaxially or biaxially drawn films.
• an energy storage device whether a battery, a capacitor, a supercapacitor and the like, is manufactured and thus provided in accordance with the disclosure wherein at least one current collector that exhibits the properties associated with no appreciable current movement after a short is contacting a cathode, an anode, or two separate current collectors contacting both, and a separator and electrolytes, are all present and sealed within a standard (suitable) energy storage device container, is provided.
• the cathode, anode, container, electrolytes, and in some situations, the separator, components are all standard, for the most part.
• the current collector utilized herewith and herein, however, is, as disclosed, not only new and unexplored within this art, but counterintuitive as an actual energy storage device component. Such is, again, described in greater detail below.
• the conductive nature of the thin current collector material allows for short circuit electrical charges to merely reach the thin conductive current collector and immediately create a short duration high-energy event that reacts between the metal at the current collector surface with the electrical charge itself, thereby creating a metal oxide to form at that specific point on the current collector surface.
• the metal oxide provides insulation to further electrical activity and current applied dissipates instantaneously, leaving a potential deformation within the collector itself, but with the aforementioned metal oxide present to protect from any further electrical charge activity at that specific location.
• the remaining current collector is intact and can provide the same capability as before, thus further providing such protections to any more potential short circuits or like phenomena.
• the anode, cathode, current collectors and separator comprise the electrical pathway which generate heat and provide the spark to ignite the cell in reaction to a short circuit, as an example.
• the further presence of ion transporting flammable electrolytes thus allows for the effective dangers with high temperature results associated with such unexpected electrical charges.
• the heat generated at the prior art current collector causes the initial electrochemical reactions within the electrolyte materials, leading, ultimately to the uncontrolled ignition of the electrolyte materials themselves.
• the disclosed inventive current collector herein particularly valuable when utilized within battery cells including such flammable electrolytes.
• such electrolytes generally include organic solvents, such as carbonates, including propylene carbonate, ethylene carbonate, ethyl methyl carbonate, di ethyl carbonate, and di methyl carbonate, and others. These electrolytes are usually present as mixtures of the above materials, and perhaps with other solvent materials including additives of various types. These electrolytes also have a lithium salt component, an example of which is lithium hexafluorophosphate, LiPF 6 . Such electrolytes are preferred within the battery industry, but, as noted, do potentially contribute to dangerous situations. Again, this inventive current collector in association with other battery components remedies these concerns significantly and surprisingly.
• a current source with both voltage and current limits can be set to a voltage limit similar to the operating voltage of the energy storage device in question.
• the current can then be adjusted, and the current collector tested fewer than two configurations.
• a short strip of the current collector of known width is contacted through two metal connectors that contact the entire width of the sample.
• the current limit of the current source can be raised to see if there is a limit to the ability of the material to carry current, which can be measured as the total current divided by the width, achieving a result in A/cm, herein designated as the horizontal current density.
• the second configuration would be to contact the ground of the current source to one of the full width metal contacts, and then touch the tip of the probe, approximately 0.25 mm 2 , to a place along the strip of the current collector. If the current is too high, it will bum out the local area, and no current will flow. If the current is not too high for the current collector, then the full current up to the limit of the current source will flow. The result is a limit of current in A/mm 2 , herein designated as the vertical current density. In this way, a current collector which can reach a high current under both configurations would be similar to the prior art, and a current collector which could support the horizontal current when contacted under full width, but would not support a similar vertical current under point contact would be an example of the invention herein described.
• a current collector may be able to support horizontal current density 0.1 A/cm, or 0.5 A/cm, or 1 A/cm or 2 A/cm or even 5 A/cm. And for a current collector that could support a horizontal current density as above, it would be desirable not to support a vertical current density of 0.1 A/mm 2 , or 0.5 A/mm 2 , or 1 A/mm 2 or 2 A/mm 2 or even 5 A/mm 2 .
• the metalized thin film collectors actually allow for an effective and strong weld of the tab thereto and with the ability to actually allow for conductance at both film sides.
• the tab itself is actually thicker than each individual current collector and when placed in contact with one another the weld may be undertaken to a depth that is partially through the tab material in relation to the shape and depth of the weld itself.
• the surprising result is that the weld may actually pass through the tab in a thin “stream” or like formation, thus allowing for conductance through such a weld material to the tab.
• the limited, though effective, conduction path is generated in order to not only allow for the needed conductance at the weld location to the tab (and then out of the battery cell casing to an external source), but also there is provided a means to limit the actual amperage and temperature generated by such a conductive flow at each weld location.
• Such a result allows for the aforementioned control of runaway conductivity from the metalized film current collectors should a short (dendrite formation, etc.) occur since the electrical charge will stop at the actual current collector surface and no other pathway for a runaway charge is provided.
• the welds may thus be provided along the length of the tab component running along the current collector with as many as five, as one example, spaced uniformly from one another, thus allowing for effective conductivity from the foil collector(s) to the tab through the battery casing to the external source.
• the limited number of welds thus reduces, as well, the number of possible runaway charge sites, albeit with each exhibiting limited amperage, but with multiples such levels show increases in some situations, certainly.
• the number of welds per tab can be increased to accommodate the high amount of current needed for the battery to be effective in its application. In this case, it is possible to require a larger number of welds, potentially as many as 10, or 20, or even 50 welds per tab.
• welds provide a base strength, additionally, to prevent movement of the tab during utilization. Stability and rigidity and needed to ensure proper operation of the battery overall.
• the limited welds do provide a certain level of reliability in this respect, while the addition of pull tape thereover as applied to the current collector films also aids in protecting from such potential problems as well.
• the metalized thin film current collectors are unexpectedly good for the prevention of runaway charges during a short.
• the need for tab leads in sufficient contact with such collectors in order to allow for effective conductivity external the battery cell requires a structural situation that allows for such metalized thin current collector film utilization with standard tab components.
• the ability to determine proper dimensions of both current collector film(s) and tabs with suitable welds for effective attachment and contact for electrical current to pass through effectively for battery operation, while still exhibiting the proper low potential for runaway charge has proven difficult, particularly in view of the specific and accepted thick monolithic current collector components of the state of the art today.
• Such power cells which may be configured and structured with containers noted above, as well as, without limitation, metalized plastic bags, metal cans, and rigid/semi-rigid plastic enclosures, would, again, exhibit much improved potential for thermal runaway with metalized thin film current collectors.
• the proper connection between such power cells and external contacts is thus of great necessity for actual functional purposes, particularly with the complexities of providing such reliable and secure connections with thin film materials.
• certain weld configurations and actual welding tools provide for such beneficial and surprisingly effective tab-electrode connections for such unique power cell structures.
• Particularly important battery (power cell) types include, without limitation, pouch, cylinder, prismatic and jelly roll structures as these types of cells are most prevalent within certain industries and allow for greater versatility for subject devices, as well.
• the utilization of a proper weld anvil creates a certain three-dimensional divot within a subject region of the current collector such that the top (first) metalized layer becomes contacted with the lower (second) metalized layer, the polymer substrate moves in opposing relation to the weld divot and within the confines of the two metalized layers, and the resultant welded structure retains the top and lower metalized layers separated by the polymer substrate outside of the welded region.
• this may also apply to a film that is metalized on only one side, and electrical contact is desired to a component on the other side of the polymer substrate, such as a tab or the metalized side of a subsequent metalized thin film current collector.
• the weld must then be imparted such that the divot of the weld extrudes through from the metalized layer through the polymer substrate to the component with which electrical contact is desired.
• a tab material within a weld thus allows for the weld anvil to press through the tab and move the current collector (again, thin film of at least two metalized layers separated by a polymer substrate) in the same manner, thus creating a divot within the tab and current collector simultaneously for connection capabilities between both structure to form a composite for conductivity purposes.
• Such tab weld attachment may be undertaken on either of the top or bottom of such a thin film current collector as well, thereby allowing for the tab to basically connect with the top and bottom metalized layers simultaneously in either manner.
• the ability to properly and effectively connect the entire power cell structure (electrode/current collector, at least) to the target tab for the further provision of conductivity external of such an improved safety (thin film current collector) power cell is achieved.
• This ability to suitable and effectively provide conductivity from the current collector (both metalized film layers) simultaneously to such a tab for external power transmission allows for the overall functionality and, for that matter, proper utilization of such a safe battery device that has, again, heretofore been unexplored. Without the effective weld operation for both metalized film layers of the base current collector, such a power transfer would be hindered, basically.
• the current collector may be of multiple layered structures of a single polymer substrate separating two metalized layers in each such structure (in other words, repeating units of thin film polymer substrate with top and bottom metalized films as desired; at least one such base structure may be present with any number layered on one another up to about 12-15 or more, depending on the end use thereof.
• Such multiple base structure power cells would require the same needed weld connection(s) with at least one base substrate/top and bottom metalized film structures for functionality of the target power cell.
• the number of layers of metalized film that are welded together may be 15, or may be higher, as many as 25, or even 50 in a single stack.
• the maximum number of layers in a stack may be less than 250, or preferably less than 100, or even more preferably less than 50.
• More than one weld divot may be employed for such connection purposes between the thin film current collector (again, polymer substrate with top and bottom metalized films, and at least one such structure present) and the tab.
• Such welds may be provided within a small region of the current collector (and thus tab) or may be provided as repeated divots of the same three-dimensional structure in patterns thereof or possibly with different three-dimensional structures in patterned or random configurations.
• random configurations of the same three-dimensional weld structures may be employed as well.
• weld divots are to impart, again, the proper and effective connections between the tab and the current collector while allowing for the thin film to retain the needed safety aspects associated thereof (reduce the propensity of thermal runaway) while still retaining the proper ability to transfer charge and thus conductivity external to the power cell itself.
• Such weld structures allow, again, for three-dimensional structures that allow for limited regions of the tab and current collector to contact with a certain uniformity of displacement of polymer substrate allowing for the top and bottom metalized film layers to contact one another with the tab as well manipulated for contact with such a top and bottom metalized layer contact.
• Multiple divots allow for increased conductivity on demand, as well as increased surface area connections for more reliable attachment between tab and current collector, as well.
• Such three-dimensional weld divots may be made from any number of weld anvil structures, including, without limitation, rectangular (linear) three-dimensional anvils, spherical (or semi-spherical), truncated pyramid (with a square bottom and a smaller square top), rounded pyramid (with curved edges at the top thereof) , and the like.
• Such structures impart divots that will allow for the top metalized layer (or bottom depending on the location of the actual weld, whether on the top or bottom of the current collector) to deform downwardly without breaking the film and contact for a certain area with the bottom metalized layer, while the polymer substrate displaces but remains in contact to the manipulated metalized film layers to provide a force against such a manipulated region thereof for dimensional stability subsequent to such a weld operation.
• welds may be provided singly within such a tab/current collector composite structure, or may be applied in multiples for increased surface area contact between the two composite components, either uniformly, randomly, entirely (over a certain region), or sparsely (within a region).
• Such a welding operation may utilize ultrasonic, heat application (through an anvil, for instance), or pressure application (again, through the utilization of an anvil).
• Such applications may include the utilization of a single anvil or multiple anvils simultaneously within a grid that applies to and over a certain region of the tab and current collector/electrode bodies, as well (as noted above).
• Such welding capabilities thus allow for a number of other beneficial opportunities that have not been explored in the past. These include the potential for a configuration of multiple current collectors and multiple tabs, all welded together, either entirely or separately.
• a single tab may be connected through welding to multiple layers of current collectors, as well, allowing for the connections of such top and bottom metalized layers within such multi-layer structures (at least two, and any number up to, for instance, 25).
• a staggered configuration of current collectors and tabs may be employed, if desired, without compromising safety or power transfer, as well.
• Such an electrode tab may have an expanded region to allow more welds for, again, greater surface area for conductivity and/or connection purposes.
• the tab/electrode connection may be in combination with a narrowed region of tab to provide a “built in” cell fuse. Such a cell fuse may impart the ability, as well, to thereby increase the safety aspects to an even greater degree. Additional metal layers may be inserted between the current collector film layers, as well, to aid in the weld capabilities between such film stacks (particularly with multiple layers present, again, up to about 25).
• such a component is, as noted above, welded to the electrode and subsequently connected to either other cell components (within a container), or attached to (and possibly through) a target cell casing, thereby functioning as an external electrode for connection with an external device (to transfer power thereto, in other words).
• welds may be from the tab side (through the utilization of a moving horn device thereon such a surface), with the anvil (non-moving) pressed on the film side (as noted above).
• the opposite may be employed, however, with the anvil pressed into the tab with a moving horn underneath on the film side (to provide a smooth structure for the anvil to press against, ultimately).
• the ability to impart the desired weld divot for connection and adherence purposes is permitted in relation to the thin metalized current collector for such a safe, reliable and effective connection externally through the tab.
• a single tab may be employed with at least one and up to about, without any limitation, 25 metalized film layers.
• multiple tabs with from one to about 25 metalized film layers may be utilized with tabs present, as one non-limiting possibility, at the top and bottom of the metalized film layer stack.
• such multiple tabs may also be interspersed throughout the metalized film layer (current collector) stack, uniformly or sparsely, as needed and/or desired. This allows for a number of different results and possibilities for power generation and transfer with safe (low thermal runaway propensity, again) cells.
• a single tab may be utilized that is sufficient in length to fold over and around a thin film current collector (or multi-layers thereof) and basically welded not only to the thin film collector(s), but to itself (acting like a clamp around the collector(s), in effect.
• the utilization of multiple welds aids in providing sufficient connection for overall strength to the composite generated thereby as well as increased conductivity potential from the power cell externally through the tab.
• the number of welds used may be numbered to achieve a maximum current for the cell beyond which the welds will fail and break connection to the tab.
• Such welding in any number, as desired, may be applied on either electrode (anode or cathode) alone, or on both electrodes simultaneously in identical or different numbers, again, as desired.
• the process to produce a lithium ion battery with the inventive films comprises the steps of: a. Providing an electrode having at least one metalized substrate with a coating of an ion storage material; b. Providing a counterelectrode; c. Layering said electrode and counter electrode opposite each other with a separator component interposed between said electrode and said counterelectrode; d. Providing a package material including an electrical contact component, wherein said contact includes a portion present internally within said package material and a portion present external to said package material; e. Electrically connecting said electrical contact with said metalized substrate; f. Introducing at least one liquid electrolyte with ions internally within said package material; and g. Sealing said package material.
• the metalized substrate can be any substrate as described within this disclosure.
• 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 L1C0O2, lithium iron phosphate LiFePCL, lithium manganese oxide LiMniCL, 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 electrolyses 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.
• Counterelectrodes include other electrode materials that have different electrochemical potentials from the ion storage materials.
• the ion storage material is a lithium ion anode material
• the counterelectrode would be made form a lithium ion cathode material.
• the counterelectrode might be a lithium ion anode material.
• the counterelectrode can be made from either a supercapacitor material, or in some cases from a lithium ion anode or lithium ion cathode material.
• the counterelectrode would include an ion storage material coated on a current collector material, which could be a metal foil, or a metalized film such as in this invention.
• the inventive electrode is layered with the counterelectrode with the electrode materials facing each other and a porous separator between them.
• the electrodes may be coated on both sides, and a stack of electrodes formed with the inventive electrode and counterelectrodes alternating with a separator between each layer.
• strips of electrode materials may be stacked as above, and then wound into a cylinder.
• Packaging materials may include hard packages such as cans for cylindrical cells, flattened hard cases or polymer pouches.
• hard packages such as cans for cylindrical cells, flattened hard cases or polymer pouches.
• a portion of the case itself forms one means, while another is a different portion of the case that is electrically isolated from the first portion.
• the case may be nonconducting, but allow two metal conductors to protrude through the case, often referred to as tabs.
• 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.
• this weld may include contact by extruding the thin metal layer through the plastic layer to contact metal that was previously on the other side of said plastic layer, which may be in the form of divots created through ultrasonic welding or other method of welding.
• 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.
• 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.
• a cathode for a lithium iron phosphate battery was obtained from GB Systems in China.
• the aluminum tab was removed as an example of a commercial current collector, and the thickness, areal density and resistance were measured, which are shown in Table 1, below.
• the aluminum foil was then touched with a hot soldering iron for 5 seconds, which was measured using an infrared thermometer to have a temperature of between 500 and 525° F. There was no effect of touching the soldering iron to the current collector.
• the thickness, areal density and resistance were measured.
• the material was placed in an oven at 175° C for 30 minutes and the shrinkage measured. A photograph was taken and included in FIG. 6.
• FIG. 5 provides a representation of the traditional current collector within such a comparative battery. Comparative Example 2
• FIG. 5 provides a representation of the internal structure of such a battery.
• the thickness of the current collector is significant as it is a monolithic metal structure, not a thin type as now disclosed.
• Polypropylene lithium battery separator material was obtained from MTI Corporation. The material was manufactured by Celgard with the product number 2500. The thickness, areal density anodic resistance was measured, which are shown in Table 1, below. The separator was then touched with a hot soldering iron in the same way as Example 1. Touching the thermometer to the current collector created a small hole. The diameter was measured and included in Table 1. The thickness, areal density and resistance were measured. The material was placed in an oven at 175° C for 30 minutes and the shrinkage measured. A photograph was taken and included in FIG. 7.
• Ceramic coated polyethylene lithium battery separator material was obtained from MTI Corporation. The thickness, areal density and resistance were measured, which are shown in Table 1, below. The separator was then touched with a hot soldering iron in the same way as Example 1. Touching the soldering iron to the current collector created a small hole. The diameter was measured and included in Table 1. The thickness, areal density and resistance were measured. The material was placed in an oven at 175° C for 30 minutes and the shrinkage measured. A photograph was taken and included in FIG. 7 a.
• Ceramic coated polypropylene lithium battery separator material was obtained from MTI Corporation. The thickness, areal density and resistance were measured, which are shown in Table 1, below. The separator was then touched with a hot soldering iron in the same way as Example 1. Touching the soldering iron to the current collector created a small hole. The diameter was measured and included in Table 1. The thickness, areal density and resistance were measured. The material was placed in an oven at 175° C for 30 minutes and the shrinkage measured. A photograph was taken and included in FIG. 7b.
• Aluminized biaxially oriented polyester film was obtained from All Foils Inc., which is designed to be used for helium filled party balloons.
• the aluminum coating holds the helium longer, giving longer lasting loft for the party balloons.
• the thickness, areal density and resistance were measured, which are shown in Table 1, below.
• the film was then touched with a 49 hot soldering iron in the same way as Example 1. Touching the soldering iron to the current collector created a small hole. The diameter was measured and included in Table 1. The thickness, areal density and resistance were measured.
• the material was placed in an oven at 175° C for 30 minutes and the shrinkage measured. A photograph was taken and included in FIG. 8.
• this material is 65% thinner and 85% lighter, and also retreats away from heat, which in a lithium ion cell with an internal short would have the effect of breaking the internal short.
• Comparative Examples 1 - 2 are existing current collector materials, showing very low resistance, high areal density and no response at exposure to either a hot solder tip or any shrinkage at 175° C.
• Examples 1 - 3 are materials that have infinite resistance, have low areal density and melt on exposure to either 175° C or a hot solder tip. They are excellent substrates for metallization according to this invention.
• Example 4 is an example of an aluminized polymer film which shows moderate resistance, low areal density and shrinks when exposed to 175° C or a hot solder tip. It is an example of a potential cathode current collector composite film according to this invention. In practice, and as shown in further examples, it may be desirable to impart a higher level of metal coating for higher power batteries.
• Examples 5 - 6 are materials that have infinite resistance, have low areal density, but have very low shrinkage when exposed to 175° C or a hot solder tip. They are examples of the polymer substrate under this invention when the thickness of the metalized coating is thin enough such that the metalized coating will deteriorate under the high current conditions associated with a short. Additionally, the cellulose nanofibers and polyester microfibers will oxidize, shrink and ablate at temperatures far lower than the melting temperatures of the metal current collectors currently in practice.
• Example 5 additionally is made from a fiber, poly acrylonitrile, that swells on exposure to traditional lithium ion carbonate electrolytes, which is also an example of a polymer substrate under this invention such that the swelling will increase under heat and create cracks in the metalized coating which will break the conductive path, improving the safety of the cell by eliminating or greatly reducing the uniform conductive path of the current collector on the exposure to heat within the battery.
• Example 5 The material utilized in Example 5 was placed in the deposition position of a MBraun Vacuum Deposition System, using an intermetallic crucible and aluminum pellets. The chamber was evacuated to 3xl0 5 mbar. The power was increased until the aluminum was melted, and then the power set so the deposition rate was 3 Angstroms/s. The deposition was run for 1 hour, with four samples rotating on the deposition plate. The process was repeated three times, so the total deposition time was 4 hours. The samples were measured for weight, thickness and resistance (DC and 1 kHz, 1 inch strip measured between electrodes 1 inch apart), which are shown in Table 2 below. Point resistance was also measured using a Hioki 3555 Battery HiTester at 1 kHz with the probe tips 1” apart. The weight of added aluminum was calculated by the weight added during the process divided by the sample area. This is divided by the density of the material to give the average thickness of the coating.
• Example 8 The weight of added aluminum was calculated by the weight added during the process divided by the sample area. This is divided
• a nonwoven polymer substrate was made by taking a polyethylene terephthalate microfiber with a flat cross section and making hand sheets at 20 g/m 2 using the process of Tappi T206. These hand sheets were then calendered at 10 m/min, 2000 lbs/inch pressure using hardened steel rolls at 250° F. This material was metalized according to the process of Example 7, and the same measurements taken and reported in Table 8.
• Example 9 Material according to Example 5 was deposited according to the process of Example 7, except that the coating was done at a setting of 5 Angstroms/second for 60 minutes. The samples were turned over and coated on the back side under the same procedure. These materials were imaged under a scanning electron microscope (SEM), both on the surface and in cross section, and the images are presented in FIGS. 9, 9a, and 9b.
• SEM scanning electron microscope
• Example 8 The polymer substrate of Example 8 was prepared, except that the sheets were not calendered. The deposition of aluminum is at 5 Angstrom s/second for 20 minutes on each side. Because the materials were not calendered, the porosity is very high, giving very high resistance values with a thin coat weight. Comparing Example 11 to Example 8 shows the benefits of calendering, which are unexpectedly high.
• the aluminum coated polymer substrate from Example 9 was coated with a mixture of 97% NCM cathode material (NCM523, obtained from BASF), 1% carbon black and 2% PVDF binder in a solution of N-Methyl-2-pyrrolidone.
• the coat weight was 12.7 mg/cm 2 , at a thickness of 71 microns.
• This material was cut to fit a 2032 coin cell, and paired with graphite anode coated on copper foil current collector (6 mg/cm 2 , 96.75% graphite (BTR), 0.75% carbon black, 1.5% SBR and 1% CMC).
• a portion of the aluminum coated polymer substrate from Example 9 was left uncoated with cathode material and folded over to contact the shell of the coin cell, completing the conductive pathway.
• the cell was formed by charging at a constant current of 0.18 mA to 4.2 V, and then at constant voltage (4.2 V) until the current dropped to 0.04 mA.
• the cell was cycled three times between 4.2 V and 3.0 Vat 0.37 mA, and gave an average discharge capacity of 1.2 mAh
• a cell was made according to the procedure and using the materials from Example 12, except the separator used was Dreamweaver Silver 20.
• the cell was formed by charging at a constant current of 0.18 mA to 4.2 V, and then at constant voltage (4.2 V) until the current dropped to 0.04 mA.
• the cell was cycled three times between 4.2 V and 3.0 Vat 0.37 mA, and gave an average discharge capacity of 0.8 mAh.
• working rechargeable lithium ion cells were made with an aluminum thickness of less than 1 micron.
• the aluminum tab of Comparative Example 1 approximately 2 cm x 4 cm was connected to the ground of a current source through a metal connector contacting the entire width of the sample.
• the voltage limit was set to 4.0 V, and the current limit to 1.0 A.
• a probe connected to the high voltage of the current source was touched first to a metal connector contacting the entire width of the sample, and then multiple times to the aluminum tab, generating a short circuit at 1.0 A.
• the tip of the probe was approximately 0.25 mm 2 area. When contacted across the entire width, the current flowed normally. On initial touch with the probe to the tab, sparks were generated, indicating very high initial current density.
• the experiment was repeated with the current source limit set to 5.0, 3.0, 0.6 A, 0.3 A and 0.1 A, and in all cases the result was a continuous current at the test current limit, both when contacted across the entire width of the current collector and using the point probe of approximately 0.25 mm 2 tip size.
• Example 7 The inventive aluminum coated polymer substrate material of Example 7 of similar dimensions was tested using the same method as Comparative Examples 3-4. When contacted across the entire width, the current flowed normally. In each case of the touch of the probe to the inventive current collector directly, the sparks generated were far less, and the current ceased to flow after the initial sparks, leaving an open circuit. In all cases, the resultant defect was a hole. Micrographs of several examples of the holes are shown in FIGS. 11 and 11a.
• the experiment was repeated with the current source limit set to 5.0, 3.0, 0.6 A, 0.3 A and 0.1 A, and in all cases the result a continuous flow of current when contacted through the full width connectors, and no current flowing through the inventive example when contacted directly from the probe to the inventive current collector example.
• the key invention shown is that, when exposed to a short circuit as in Comparative Examples 3 - 4 and in Example 14, with the prior art the result is an ongoing short circuit, while with the inventive material the result is an open circuit, with no ongoing current flowing (i.e., no appreciable current movement).
• the prior art short circuit can and does generate heat which can melt the separator, dissolve the SEI layer, and result in thermal runaway of the cell, thereby igniting the electrolyte.
• the open circuit of the inventive current collector will not generate heat and thus provides for a cell which can support internal short circuits without allowing thermal runaway and the resultant smoke, heat and flames.
• Two metalized films were produced on 10 micron polyethylene terephthalate film in a roll to roll process.
• a roll of the film was placed in a vacuum metallization production machine (an example of which is TopMet 4450, available from Applied Materials), and the chamber evacuated to a low pressure.
• the roll was passed over heated boats that contain molten aluminum at a high rate of speed, example 50 m/min.
• a plume of aluminum gas which deposits on the film, with the deposition rate controlled by speed and aluminum temperature.
• a roll approximately 500 m long and 70 cm wide was produced through multiple passes until the aluminum coating was -300 nm.
• Example 16 was thus produced in the same way, except the metal in the boat was copper (and with the depiction of FIG. 5B representing the current collector utilized within this inventive structure).
• the basis weight, thickness and conductivity of each film were measured, and are reported below in Table 3.
• the coating weight was calculated by subtracting 13.8 g/m 2 , the basis weight of the 10 micron polyethylene terephthalate film.
• the “calculated coating thickness” was calculated by dividing the coating weight by the density of the materials (2.7 g/cm 3 for aluminum, 8.96 g/cm 3 for copper), and assuming equal coating on each side.
• Comparative Example 5 is a commercially obtained aluminum foil 17 microns thick.
• Comparative Example 6 is a commercially obtained copper foil 50 microns thick.
• Comparative Example 7 is a commercially obtained copper foil 9 microns thick.
• Example 15 Example 16, Comparative Example 5 and Comparative Example 6 were subjected to a further test of their ability to carry very high current densities.
• a test apparatus was made which would hold a polished copper wire with radius 0.51 mm (24 AWG gauge) in contact with a current collector film or foil.
• the film or foil under test was grounded with an aluminum contact held in contact with the film or foil under test, with contact area > 1 square centimeter.
• the probe was connected in series with a high power 400 W resistor of value 0.335 ohms, and connected to a Volteq HY3050EX power supply, set to control current.
• the current collector to be measured was placed in the setup, with the polished wire in contact with the surface of the current collector at zero input current.
• Example 15 failed at a 7 A (average of two measurements).
• Example 16 failed at 10.2 A (average of two measurements). Neither of Comparative Example 5 nor Comparative Example 6 failed below 20 A. Both Example 15 and Example 16 showed holes in the current collector of radius > 1mm, while neither of the Comparative Examples 5 or 6 showed any damage to the foil. In this example test, it would be advantageous to have a current collector that is unable to carry a current of greater than 20 A, or preferably greater than 15 A or more preferably greater than 12 A.
• Examples 15 and 16 and Comparative Examples 5 and 6 were subjected to a current capacity test along the strip.
• the current collectors were cut into the shape shown in FIG. 12, which consists of a strip of material that is four centimeters by on centimeter (4 cm x 1 cm), with the ends of the strip ending in truncated right isosceles triangles of side 4 cm. Each of the triangles of the test piece was contacted through a piece of aluminum with contact surface area > 1 cm.
• NMC 523 cathode materials were prepared using BASF NMC523 (97%), carbon black (2%) and PVDF (1 %) in NMP solvent, and coated on the aluminum current collector (15 micron aluminum current collector) and Example 15 were at a basis weight of 220 g/m 2 , corresponding to a cathode loading density of 3.3 mAh/cm 2 .
• Anode materials were prepared by using graphite BTR-918S (94%), carbon black (5%) and PVDF (1%) in NMP solvent, and coating on the copper current collector (18 micron copper current collector) at 118 g/m 2 , corresponding to an anode loading density of
• FIG. 13 shows a single thin film current tab/collector 600 with a metalized film layer 614 and a lower non-metal layer 616.
• a conducting tab 610 (to lead to the external power transfer component of a battery) is provided as well, aligned perpendicularly to the collector, and connected thereto with welds 612.
• FIG. 14 shows a similar current collector 620 but with a tab 622 present with tape 624 connecting the tab 622 to the collector 634 for such a conductive purpose.
• the tab/current collector 620 has a metalized film layer 626 and a lower non- metal layer 632.
• the tape component 622 is provided on the outer surface 628 of the tab and leading to the non-metal layer 626 of the current collector, provided a shear strength adhesive quality for the tab to remain secured and in suitable manner for conduction purposes.
• FIG. 15 provides a different tab/collector 640 showing a different manner of connecting a tab 642 to a single thin current collector 648 (with a metalized film layer 644 and a lower non-metal layer 650), connecting the two components through the utilization of conducting staple components 646.
• FIG. 18 likewise includes a flat tab/current collector 750 with the same type of upper 758 and lower surface 762 as above.
• the tab 752, 754, in this instance, is provided as two parallel structures with contact with both the top 758 and lower surfaces 760 of the current collector 762.
• Such a tab 752, 754 includes welds 756 for connection to and with both surfaces 758, 760.
• FIG. 17 shows a similar structure 780 to FIG. 16, but with a single folded tab 794 in place that is in contact with both surfaces 788, 790 of the current collector 792 through welds 786 with two extended prongs 782, 784 of the folded tab 794 leading therefrom.
• FIG. 16 shows a single fold 710 tab/current collector 700 with a single taped tab 702 attached thereto the metalized film surface 712 (which covers, as above, the non-metal layer 708).
• the single fold 710 current collector 704 imparts the capability of an increase in power generation within the battery cell as a result, albeit with the need for a slight increase in battery size from the flat structure.
• FIG. 17 depicts a double folded 732 tab/current collector 720 utilizing the same thin structure collector 724.
• FIG. 20 shows a welded 804 tab 802 to a double folded 810 tab/current collector 800, thus exhibiting the same ability to connect electrically isolated layers 808, 812 as above as part of the collector 806, but with safer welds 804 in place to more reliably and more potentially effective for power transfer purposes.
• FIG. 20 shows a welded 804 tab 802 to a double folded 810 tab/current collector 800, thus exhibiting the same ability to connect electrically isolated layers 808, 812 as above as part of the collector 806, but with safer welds 804 in place to more reliably and more potentially effective for power transfer purposes.
• FIG. 21 thus shows a composite tab/multiple collectors structure 820 with a plurality (here five) of such double rounded folded 856 current collectors 826,828, 830, 832, 834 with metalized film layers 858, 860, 862, 864, 866 and lower non-metal layers 846, 848, 850, 852, 854, connected in a series for even more ability to connect electrically isolated layers for conductivity through a single tab 822 with welds 824 connecting for conductance with the top double rounded folded collector 826.
• the welded tab 822 stays in place strongly for improved reliability purposes, as well.
• a second, opposite, welded 906 tab 904 is provided in FIG.
• Such a tabs/collectors structure 900 allows for increased power generation without necessitating weight of volume increases for the subject battery cell through the two tabs 902, 904 configured and connected with the two outer collectors 908, 916, as noted previously.
• Metalized film layers 940,942,944,946,948 are, as above, provided with opposing non-metal layers 928, 930, 932, 934,936 are present as with such other collector examples.
• a multi -Z-fold 972 tab 962 clamped to a series of parallel flat thin current collectors 964, 966, 968, 970 (here four)(as described above), with metalized film layers 974, 978, 982, 986 and lower non-metal layers 976, 980, 982, 984, again, to provide a different manner of generating cumulative power in a series, albeit with flat thin current collectors 964, 966, 968, 970 (acting as multiple internal fuses).
• FIGS. 13-23 thus allow for different external connections to the internal fuse components of a standing lithium battery.
• FIG. 24 shows a single-welded composite of a thin film current collector 1010 having a middle polymer substrate 1015 and a top metalized film 1012, a bottom metalized film 1014, a weld divot 1020 with a weld direction 1018 indicated, and an interface 1022 of the top 1012 and bottom metalized films 1014.
• the polymer substrate 1015 has been manipulated outwardly 1016 from the weld divot 1020 to allow for the interface 1022 connection between top 1012 and bottom 1014 metalized films. Careful control of the welding parameters is needed to move the polymer without also destroying the metal, in general using less power and more pressure.
• FIG. 24 shows the profile of a single ideal node. In practice, many nodes will be present and can be configured with different cross sections and node configurations as depicted in FIGS. 34, 35, 35a, 36, and 37. The desirable effect is to maximize the interface 1022 by varying the node geometry and processing parameters such as power, frequency and pressure, if for ultrasonic welding, or temperature and pressure if for thermal welding.
• FIG. 25 shows a welded composite 1030 of a tab 1032 and thin film current collector (1010 of FIG. 24) with atop metalized film 1012, polymer substrate 1015, and bottom metalized film 1014.
• the top-applied weld 1020 moves the polymer substrate 1015 for the metalized films 1012, 1014 to contact.
• the tab 1032 likewise contacts with the top film 1012 in relation to the weld direction 1034 for connection between the tab 1032 and current collector (1010 of FIG. 24) allowing for conductivity from the bottom film 1014 through the top film 1012 to the tab 1032.
• FIGS. 26 and 26a show microphotographs (100- and 50-micron lengths, respectively) of weld interfaces of such a composite of metalized film 1012, polymer substrate 1015 and bottom film 1014.
• the weld direction 1018 presses the metalized film 1012 to and bottom film 1014 in such a manner as to produce a connection between the two materials 1013 through the polymer substrate 1015.
• This connection 1013 permits percolation between the top film 1012 and bottom film 1014 to facilitate and optimize the conductivity from the metalized film 1012 to a tab (1042 in FIG. 27, for example) for improved battery operation.
• FIG. 27 shows a tab/current collector composite 1040 with the same current collector as in FIG. 24 (1010) and a tab 1042 connected with the bottom film layer 1014.
• the polymer substrate 1015 With the top weld 1020 applied to the current collector top film 1012, the polymer substrate 1015 is moved to allow for the top 1012 and bottom 1014 films to interface, thus permitted conductivity between the metalized films 1012, 1014 and the tab 1042.
• FIGS. 27a and 27b show photomicrographs of the interface of the weld interface between the bottom film and the tab, showing the clear delineations therein.
• FIG. 27b particularly shows the tab and bottom film welded layer interface with metallic debris present from the metalized film during the weld process.
• FIG. 28 shows a tab/current collector composite 2040 with a similar top thin film metalized film collector 2042 to the current collector as in FIG. 24 (1010) and a tab 2044 connected with a bottom film layer of a multi-layered metalized film structure 2046 (with polymer substrate in-between each individual layer). Such layers may be extruded to form such a multiple-layer structure 2046 on top of the tab 2044 itself.
• the layers 2046, including the top layer 2042 are of the same thin film structure as that in FIG. 24 (1010).
• the multiple layers 2042, 2046 manipulated through a weld divot 2048 to connect the multiple layers 2042, 2046 together at a weld interface 2049.
• the weld divot 2048 may be applied in such a manner as to generate a graduated contour 2047 surrounding the full weld divot 2048 to facilitate the full weld pressure application through the multiple current collector layers 2042, 2046.
• a contour 2047 there is further generated a raised peripheral edge 2045 at the top edge thereof the weld divot 2048.
• the resultant composite 2040 thus allows for conductivity between all of the metalized film collector layers 2042, 2046 to the tab 2044 for further utilization within a battery for external power transfer.
• FIGS. 28a and 28b provide photomicrographs of the same composite structure of FIG. 28.
• the weld interface 2049 connects such multiple collector layers 2042, 2046 to the tab 2044.
• a visible contour 2047 surrounding the weld with a raised peripheral edge 2047 is also present.
• the weld interface 2049 shows the presence of film collector portions within the polymer substrate to allow for conductivity between not only the top thin film collector layer 2042 and the tab 2044, but also the multiple collector layers 2046 with the tab 2044.
• such a composite 2040 allows for a battery transfer capability from a cell externally through such a tab 2044.
• FIG. 29 provides a different possible composite 1050 of tab 1054, atop metalized film 1052 and multiple layers of metalized film current collectors 1058 connected to each other through a weld 1056, thus allowing for conductivity of such metalized films 1058, 1052 through to the tab 1054.
• FIGS. 30, 31, and 32 show different types ofbattery devices utilizing the welded tab to a thin current collector power cell.
• FIG. 30 shows a battery 1060 with a rigid plastic container 1062, the power cell 1066 and the connected external tab 1064 for further connection to a device (not illustrated).
• FIG. 31 shows a cylindrical battery 1070 with a container 1072, power cell (electrode/current collector) 1074 and extending tab 1076.
• FIG. 32 shows a pouch battery 1080 with a pouch container 1082, a power cell 1084, and connected external tab 1086, again, for contact with an external device (not illustrated).
• FIGS. 33 and 33a show power cell composites 1090 having multiple tabs 1098, multiple electrode/current collector layers 1096, a top tab 1094, and a top electrode current collector layer 1092, all welded together as described herein.
• FIGS. 34, 35, 35a, 36, and 37 pertain to different potential embodiments of weld anvil structures and pattems/configurations for utilization within and imparting weld divot shapes and structures (three-dimensional) within target tab/power cell composites.
• FIG. 34 shows a number of different possible anvil structure embodiments 1100.
• One is a linear 1102 structure having a rectangular structure in three dimensions.
• Also shown are a truncated pyramid three- dimensional structure 1108 (with a narrowing slope from a square edge to a smaller square top), a rounded pyramid structure 1106, and a spherical structure 1104 (with ribbed peripheries).
• FIG. 35 thus shows one possible embodiment of repeating truncated pyramid structures 1110 in a full grid to apply welds in like pattern.
• FIG. 35a shows another possible embodiment of a grid of sparsely populated truncated pyramid anvils 1120 for the same purpose.
• FIGS. 36 and 37 relate to uniformity of grids of truncated pyramids 1130, 1140 for patterned application to target composites (staggered as compared with aligned).
• FIGS. 38 and 39 show different potential embodiments of a top weld (FIG. 38) and a bottom weld (FIG. 39).
• FIG. 38 shows a welded composite 1150 with a tab 1154, metalized film(s) 1152, a top weld direction 1154, and a finished weld 1156 connecting the metalized film(s) 1152 with the tab 1154.
• FIG. 39 shows a welded composite 1160 with a tab 1164m metalized film(s) 1162, a bottom weld direction 1164, and a finished weld 1166 connecting the metalized film(s) 1162 with the tab 1164.
• FIG. 40 shows a possible embodiment of a welded composite 1170 with a single folded tab 1174 having a single bend 1175, a current collector/electrode 1172, and multiple welds 1176 between the tab 1174 and the current collector/electrode 1172, and an end weld 1178 for the tab to attach to itself.
• Fig, 41 shows a possible embodiment of a welded composite 1180 of staggered metalized film current collectors 1182 and staggered tabs 1184 with multiple welds 1186 for attachment of such collectors 1182 and tabs 1184 together. In this configuration, each metal face of each current collector 1182 comes in face-to-face contact with at least one of the tabs 1184.
• FIG., 42 shows a possible embodiment of a welded composite 1190 with an electrode/current collector 1192 connected to a fuse area 1198 that is welded to a tab 1194 within a limited weld area 1196 at the fuse area 1198.
• These embodiments provide some showing of the versatility available in relation to such welding techniques with thin film current collectors.
• FIGS. 43, 44, and 45 provide depictions of possible embodiments in relation to reinforcements to supplement such welding operations within power cell composites.
• FIG. 43 shows a welded composite 1200 having opposing electrodes 1202, 1204 with a welded tab 1208, a reinforcement tape 1206, and a further overlap 1210 for such increased reinforcement capabilities.
• FIG. 43 shows a welded composite 1200 having opposing electrodes 1202, 1204 with a welded tab 1208, a reinforcement tape 1206, and a further overlap 1210 for such increased reinforcement capabilities.
• FIG. 44 shows a multi -film welded composite 1220 with multiple thin films 1224, a top layer thin film 1222, and a welded tab 1226.
• a reinforcement tape 1228 is applied at the tab weld (not shown) again to increase the applied pressure for reinforcement capability over such a weld area.
• FIG. 45 shows a multi-film welded composite 1230 having multiple thin films 1234, a top layer thin film 1232, and a welded tab 1236. Applied over a weld interface is a clamp 1238 to reinforce such weld(s) (not illustrated). Thus, reinforcement of such welds may be accomplished through a number of different possible alternatives.

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