EA043346B1 - BATTERY CONNECTIONS AND METALLIZED FILM COMPONENTS IN INTERNALLY FUSED ENERGY STORAGE DEVICES - Google Patents

Description

Field of technology

The present invention relates to improvements in the structural components and physical characteristics of lithium battery products. For example, traditional lithium-ion batteries are subject to certain short-circuiting events that expose them to high temperatures and can eventually ignite. The structural properties of battery components have been found to be one source of such problems. Improvements presented herein include the use of thin metallized current collectors (eg, aluminum and/or copper), materials with high shrink rates, materials that become nonconductive when exposed to high temperatures, and combinations thereof. Such improvements provide the ability to counteract certain shortcomings (dendrites, sudden surges in electrical voltage, etc.) in the design of the target lithium battery by providing an internal fuse in the design of the subject lithium batteries themselves, which prevents unwanted results from exposure to high temperatures in cases of short circuit . Battery products and methods for using them incorporating such improvements also fall within the scope of the present invention.

Of particular interest and importance is providing a lithium battery cell that includes the necessary tabs to allow conduction from its inside to the outside to power the device in question, which may be a non-trivial condition due to the thinness of the electrodes, and likely ensuring that the two sides electrode material could not be conductive to each other. The present invention provides reeds that exhibit sufficient levels of safety in combination with the internal fuse characteristics noted above, while also having the tensile strength to remain in place during use, as well as completely covering the thin film metallized pantographs to provide this electrical conductivity result. Such tabs are further provided with optimal welds to provide the necessary contacts at levels that represent impressive levels of current and heat resistance to achieve the basic result of an internal fuse with the aforementioned sufficient conductivity for an external device. With this tongue-type component and this welded structure, further improvement is provided in the field of lithium battery production.

In addition, improvements to the internal fuse disclosed herein, in the form of extremely thin pantograph structures, further enable it to be folded repeatedly within a single element. This folding capability allows the two sides of a susceptor, which might otherwise be electrically insulated by a polymer layer sandwiched between two conductive layers, to be connected without adding to the internal weight and/or volume of the battery. The gusseted current collector appears to retain the characteristics of the internal fuse while providing this increase in power, theoretically allowing any number of power increases within any number of sized batteries without the need for the aforementioned increases in weight and volume, and leading to the creation of new battery products for different targets with specified high power levels and the greatest possible safety benefits.

State of the art

Lithium batteries are still common throughout the world as a source of electricity for many products. Because of their reliability, rechargeability, and longevity noted above, lithium batteries (with a variety of ion types) are used as the primary power source in everything from rechargeable power tools to electronic cars to the ubiquitous cell phones (and similar tablets, laptops, etc.). d.). However, there are certain problems with such widely used power supplies, some of which are becoming more serious. In particular, safety issues have emerged where certain deficiencies in such lithium batteries, whether due to initial problems associated with their manufacture or problems associated with their degradation over time, cause vulnerability to fire voltage during a short circuit. Basically, it has been found that internal defects in conductive materials create unwanted high heat and ultimately lead to fires inside such battery structures. As a result, certain products that use lithium batteries—ranging from portable computer devices (the Samsung Galaxy Note 7 smartphone, in one notorious case) to entire aircraft (the Boeing 787 passenger jet)—were banned from sale and/or use until then. , until solutions are found for the compromised lithium batteries and related products they use (and even to the point where the Samsung Galaxy Note 7 smartphone was banned for use on any aircraft in certain regions). Even Tesla's line of electric vehicles has demonstrated noticeable problems with lithium battery components, resulting in loud and

- 1,043,346 attention-grabbing stories of such expensive vehicles exploding like fireballs due to battery problems. Thus, to this day, there are widespread withdrawals or outright bans related to such problems with lithium batteries, which leads to a significant need to overcome them.

These problems primarily exist due to manufacturing defects, whether related to the individual battery components as they are manufactured or essentially to the fact that such components are designed as individual batteries. Taking a closer look, lithium batteries are currently made from six main components: a cathode material, a cathode current collector (such as aluminum foil) on which the cathode material is applied, an anode material, an anode current collector (such as copper foil) on which the anode material is applied. material, a separator located between each anode and cathode layers and usually made of a plastic material, and an electrolyte in the form of a conductive organic solvent that saturates the other materials, thereby providing a mechanism for ion conduction between the anode and cathode. These materials are usually wound together in a metal container, as shown in FIG. 1 from the prior art, or stacked one on top of the other. There are many other configurations that are and can be used for such battery manufacturing purposes, including pouch cells, prismatic cells, disk cells, cylindrical cells, coiled prismatic cells, coiled pouch cells, etc. When properly manufactured and handled with care, these battery cells can provide power for a variety of applications over thousands of charge-discharge cycles without any noticeable safety issues. However, as mentioned above, certain events and in particular certain defects can cause an internal short circuit between internal conductive materials, which can lead to heat generation and internal thermal runaway, which is known to be a major cause of fire hazard in such lithium batteries . As noted above, such events may additionally be caused by internal defects, including the presence of metal particles within the battery, burrs on pantograph materials, small pinhole defects or holes in the separator (whether present or caused during subsequent processing), mismatches between the layers of the battery (which leaves openings for unwanted conduction to occur), external debris entering the battery (for example, road particles striking a moving vehicle), destruction and/or destabilization of the cell itself (for example, due to accidents), charging an element in a confined space, etc. Generally speaking, these types of defects are known to cause the formation of a small electronically conductive channel between the anode and cathode. When such an event occurs, and if the cell is charged at the same time, such a conductive path can cause the cell to discharge, which ultimately leads to the generation of excessive heat, thereby damaging the structure of the battery and endangering the underlying device that is thus powered. It has been shown that when flammable organic solvents are used as battery electrolytes (which are normally required for battery performance), this excessive amount of heat causes them to ignite, ultimately creating a very dangerous situation. Such problems are difficult to control, at least once they occur, and have resulted in significant consumer injury. Such a potentially dangerous situation should certainly be avoided by providing a battery that produces electrical energy without introducing such a problem with flammable organic electrolyte.

The generation of excessive internal heat may further cause the plastic separator to shrink, causing it to move away, detach, or otherwise increase the short circuit area within the battery. In such a situation, a large open short circuit area within the battery can result in continuous current flow and increased heating within the battery, resulting in high temperatures that cause significant damage to the cell, including explosion, dumping, and even ignition and combustion. Such damage is particularly problematic due to the potential for fire, and worse, it occurs quickly and can lead to the explosion of the battery and, in principle, the underlying device, which also exposes the user to significant danger.

Lithium batteries (of many different types) are particularly susceptible to short circuit problems. Conventional batteries tend to exhibit increased discharge rates when exposed to high temperatures, sometimes resulting in runaway (uncontrollable) combustion and combustion, as noted above. Because of these capabilities, certain regulations have been put in place to govern the actual operation, storage, and even transportation of such battery products.

The ability to implement a proper protocol to prevent such uncontrollable short-circuit events is certainly of great importance. However, the next challenge remains: how to actually solve such problems, especially when component production is carried out by many suppliers and from many different locations around the world.

- 2 043346

Some are completely focused on trying to use suitable and/or improved separators as a means to help reduce the likelihood of these lithium battery fires. Plastic membranes with low melting points and/or shrink rates appear to provide a higher likelihood of battery fires. The general idea here was to apply certain coatings to such separator materials without reducing their ability to separate electrolyte during actual operation. Thus, ceramic particles, for example, have been used as coatings on polypropylene and/or polyethylene films, serving as a means of increasing the dimensional stability of such films (eg, increasing the melting point). Binder polymers have also been included as a component to improve cohesion between ceramic particles and adhesion to the plastic membrane (film). In reality, however, it has been found that the thermal increase imparted to the entire ceramic particle coated film structure is relatively small, making the primary factor in this separator problem the actual separator material(s) itself.

As a result, separator materials have been developed and marketed, at least to some extent, that are much more heat resistant than the porous films of polyethylene and polypropylene that comprise the base layer of such conventional ceramic-coated separators. These dimensionally stable, low shrinkage separators exhibit less than 5% shrinkage when exposed to temperatures of at least 200°C (up to temperatures of 250, 300 and even higher), which is much better than the high shrink rates exhibited by uncoated polymer films (with shrinkage). approximately 40% at 150°C) and ceramic coated films (more than 20% at 180°C) (such comparisons of shrinkage measurements are presented in FIG. 2 of the prior art). Such low shrinkage rate materials may alter the thermal decomposition mechanism within the target element when a short circuit occurs. Generally speaking, when a short circuit occurs, heat will always be generated in such a battery cell. If the separator does not shrink due to such a short circuit event, heat will continue to generate and accumulate until the other material inside the battery decomposes. This phenomenon was simulated using an industry standard nail penetration test. For example, even with a separator incorporating para-aramid fiber and demonstrating shrinkage resistance up to 550°C, the test battery in question showed a short-circuiting tendency with unique internal results. Such a cell was examined more closely after a treatment in which the cell was opened, excess electrolyte evaporated, the cell was filled with epoxy resin and then cut perpendicular to the nail remaining in the cell. Scanning electron microscope images were then obtained using backscattered electron imaging (BEI) spectra, allowing the different battery cells to be mapped to show the effect of such nail penetration. This is shown in Fig. 3A and 3B from the prior art.

It should be noted that in FIG. 3A from the prior art, copper layers always come closer to the nail than aluminum layers. It should also be noted that the highly stable separator between the electrodes is still intact. In fig. Prior art 3B shows the end of one aluminum layer at higher magnification, where it can be seen to end in a layer of cracked gray matter. It was examined by BEI, which showed that the resulting substance was in fact aluminum oxide - an insulating ceramic. Such findings led to the proposed conclusion that when the separator itself is heat resistant, the aluminum pantograph will oxidize, effectively breaking the circuit (and as a result stopping any short circuit once the insulating alumina has formed). Once the circuit is broken, current stops flowing and no more heat is generated, reversing the process that leads to thermal runaway in the case of less stable separators.

This possible solution, however, is limited to simply replacing the separator with one that has higher shrinkage rate characteristics. While such a simple solution may seem very beneficial, there are still other manufacturing procedures and certain components (such as ceramic coated separator types) that are widely used and may be difficult to replace in established battery products. Thus, despite the obvious benefits of using and incorporating heat-resistant separators, unwanted battery fires can still occur, especially when ceramic-coated separator products are considered safe for such applications. Thus, it has been determined that there is at least another, purely internal, structural mechanism of the battery cell that can correct or at least reduce the likelihood of heat generation due to an internal short circuit, in addition to the use of such high temperature resistant separator materials. In such a situation, the occurrence of a short circuit in such a battery cell will not result in devastating high temperature damage due to interruption of the closed internal circuit by effectively creating an internal fuse. However, until now, nothing has been introduced in the lithium battery industry that easily solves these problems. The present

- 3 043346 the invention provides a much desired remedy for these problems, which makes lithium battery cells extremely safe and reliable in many markets.

Of additional and special interest is consideration of proper conduction of electrical charge from the lithium-ion battery in question to an external source. This is usually achieved by the use of a tongue that contacts and attaches to the current collector, or perhaps in some way to the anode and cathode current collectors, to provide the required conductivity property with an external source. The tab appears to function as a contact with such internal battery components and extends beyond the battery cell body with point contacts for such conduction purposes. Thus, the tab must remain in place and not become detached from the pantograph(s) and provide continuous access to the external source without, again, being dislodged internally or disconnected from it externally. Since there has been no disclosure in the lithium-ion battery industry regarding such thin film current collectors, there is also nothing known that attempts to improve or optimize such reed connection problems. Of course, standard reed types are well known and connect to the large pantographs of standard battery cells; however, no considerations are presented regarding protection from the effects of thin film current collectors (eg, via an internal fuse) while generally providing a dimensionally robust result to prevent battery failure due to design flaws. As such, nothing like this has been discussed or disclosed in the prior art or lithium-ion battery industry. The present invention nevertheless overcomes such paradigms and provides a result that has not yet been discovered and/or studied in the relevant industry.

The essence of the invention

A distinct advantage of the present invention is the ability to provide, through structural components, a mechanism to interrupt the conductive path when an internal short circuit occurs, stopping or significantly reducing the flow of current that may generate heat within the target battery cell. Another advantage is the ability to provide a protective structural arrangement within a lithium battery cell that also advantageously reduces the weight and cost of manufacturing, shipping, and operating the overall cell. Thus, another advantage is the creation and retention of an internal fuse structure in the target battery cell until the need arises to activate it. Another advantage is the provision of a lighter battery by using a thin film base current collector, which prevents thermal runaway during a short circuit or similar event. Another advantage is the ability to use flammable organic electrolytes in the battery without any noticeable tendency for them to ignite during a short circuit or similar event. Another distinct advantage is the ability to provide a sufficiently conductive reed component welded or otherwise in contact with the internally fused pantograph, in particular in contact with both its top and bottom surfaces simultaneously. Another advantage is the ability to create folds within the thin susceptor components disclosed herein to allow aggregate power to be generated in series from a plurality of conductive internal structures to provide reliable battery results on demand without having to measure excessive weight or volume.

Thus, the present invention may encompass an energy storage device comprising an anode, a cathode, at least one polymer or fabric separator present between the anode and the cathode, an electrolyte, and at least one current collector contacting at least one of the anode and the cathode; wherein either an anode or a cathode is disposed between at least a portion of the susceptor and the separator, wherein the susceptor comprises a conductive material deposited on a substrate of polymeric material, and the susceptor ceases to conduct at the point of contact of the open short circuit region at the operating voltage of the energy storage device, wherein the voltage is at least 2.0 V. One example would be a current density at the point of contact of 0.1 ampere/mm ² with a tip size of 1 mm ² or less. Of course, for larger cells, the required threshold current density may be higher, and the cell may cease to conduct only at a current density of at least 0.3 amps/mm ² , such as at least 0.6 amps/mm ² or even more at least 1.0 ampere/mm ² . Such coated polymeric material substrate should also have an overall thickness of no more than 25 µm, as described in more detail below. Methods of using such a useful susceptor component in an energy storage device (whether a battery such as a lithium-ion battery or a capacitor, etc.) also fall within the scope of the present invention. In addition, such a thin film current collector battery product may also be provided with at least one tongue contacting the base thin film current collector through 2-50 evenly spaced and sized welds extending

- 4 043346 along the length of the pantograph, wherein at least one tab is applied to the thin film such that said at least one tab has an open top surface and a bottom surface in contact with the coated surface of the thin film pantograph, wherein the welds demonstrate the placement of conductive material , passing through the tongue from its open top surface to the coated surface of the thin film pantograph. Moreover, the use of a plurality of the above-described current collectors stacked to provide separate power generation areas that are connected in series within a single battery product is also within the scope of the present invention.

Another aspect of the present invention may be an energy storage system including an anode, a cathode, at least one separator present between the anode and the cathode, and an electrolyte. At least one thin film current collector may contact at least one of the anode and cathode. The current collector may comprise a conductive material deposited on a substrate of non-conductive material. The current collector may cease to be conductive at the point of contact of the short circuit at the operating voltage of the energy storage device. The voltage may be at least 2.0 V. At least one tab may be attached to the at least one thin film current collector. The connecting means may be configured to attach the tab to the pantograph. The connecting means may be in electrical contact with the exposed surface of the tongue and the thin film current collector. Either an anode or a cathode may be located between at least a portion of the thin film current collector and the separator.

In some or all embodiments of the present invention, the joining means may be selected from the group consisting of welds, tape, staples, intermediate metal strips, z-folded metal strips, conductive adhesives, and clamps.

In some or all embodiments of the present invention, the connecting means may consist of 2-50 connections distributed throughout the current collector to ensure uniform flow of current from the electrode materials to the reeds.

In some or all embodiments of the present invention, the pantograph may be folded to provide direct contact between opposite sides of the pantograph.

In some or all embodiments of the present invention, the separator may be polymeric, nonwoven, fabric, or ceramic.

In some or all embodiments of the present invention, the non-conductive material substrate may be a polymer film.

In some or all embodiments of the present invention, the electrolyte may be a flammable organic electrolyte.

In some or all embodiments of the present invention, the tongue may be a first tongue contacting the top surface of the pantograph and a second tongue contacting the bottom surface of the pantograph. The first and second tongues may be parallel.

In some or all embodiments of the present invention, the tab may be folded over the pantograph such that the first protrusion of the tab contacts the top surface of the pantograph and the second protrusion of the tab contacts the bottom surface of the pantograph. The first protrusion and the second protrusion may be parallel.

In some or all embodiments of the present invention, the current collector may be configured with double folds to create two electrically insulated layers.

In some or all embodiments of the present invention, a pantograph may be a plurality of pantographs connected in series, with a tab attached to a final pantograph of the plurality of pantographs.

Some or all embodiments of the present invention may include a second tab attached to a first pantograph of the plurality of pantographs. The tongue and the second tongue may be parallel.

Additionally, much higher current densities can be maintained for a very short period of time or in a probe with a very small tip. In such a situation, a larger current, such as 5 A, 10 A, or even 15 A, can be provided for a very short period of time [e.g., less than a second, alternatively less than 0.1 s, or even less than 1 ms (0.001 s)]. In the context of the present invention, although a larger current can be measured, the delivery time for that current is short enough such that the total energy transferred is very small and insufficient to generate enough heat to cause a thermal runaway event in the target battery cell. For example, a short circuit in a conventional cell architecture has been known to generate 10 amps for 30 seconds at 4.2 V, resulting in 1200 J of energy being delivered to a small local area within such a battery. This resulting measurement can increase the temperature of a 1-gram section of the battery under test by approximately 300°C, i.e. to a temperature high enough to not only melt the conventional separator material present in it, but also

- 5 043346 bring the entire cell into a state of thermal runaway (which, as noted above, can cause the aforementioned negative impact on the electrolyte materials present in it and the potential destruction of not only the battery in question, but also the device/appliance in which it is located, and also the surrounding space). Thus, it is certainly the ability to reduce the duration of a short circuit, as well as the resulting levels of delivered energy associated with such a short circuit, to low measurable joule levels that may allow thermal runaway (and the associated potential disaster) to be avoided, if not completely prevented. . For example, reducing the short-circuit time of a susceptor to 1 ms or less can subsequently reduce the amount of energy delivered to 0.04 J (as opposed to the 1200 J noted above, which would result in excessive 300°C or more, e.g. within 1 -gram local area of the accumulator in question). Thus, such a low level will only cause a temperature increase of 0.01°C within such a 1-gram local area of the battery, thereby preventing thermal runaway in the target cell and therefore the battery as a whole.

Thus, another significant advantage of the present invention is to provide the battery with a susceptor that sharply limits the delivery time of the level of current delivered to the target surface of the susceptor through the tip of the probe (to controllably simulate the effect of an internal manufacturing defect, dendrite, or external event that causes an internal short circuit in the battery in question), to less than 1 s, preferably less than 0.01 s, more preferably less than 1 ms, and most preferably perhaps even less than 100 µs, especially for much higher currents. Of course, such current will be limited by the internal voltage of the cell, which may be 5.0, 4.5, 4.2 V or even less, such as 4.0 or 3.8 V, but a minimum of 2.0 V.

This new current collector component is actually contrary to those commonly used and found in lithium (and other types of) batteries and energy storage devices today. Standard pantographs are conductive metal structures such as aluminum and/or copper panels with thicknesses that are considered to provide some type of protection to the overall battery structure, etc. These typical pantograph structures are designed to provide the highest possible electrical conductivity within weight and space constraints. However, it appears that this belief has in fact been formulated in error, particularly because the thick panels prevalent in modern energy storage devices will in fact not only arc when short-circuited, but will also contribute significantly to the runaway temperature rise , if such a situation ever arises. Such a short circuit can be caused, for example, by dendritic formation inside the separator. Such a defect (formed during manufacturing or caused by long-term use and therefore potential degradation) can cause an unexpected voltage transition from the anode to the cathode, thereby creating an increase in current and therefore temperature at the location where it occurs. Indeed, one potential source of short-circuit-inducing defect is the burrs that form on the edges of these thick, typical pantographs when they are cut or nicked by worn blades during the repetitive processes of producing many products (as is commonplace these days). However, it has been repeatedly discussed and studied that standard pantograph materials simply have a tendency to spark and allow the temperature to rise, and also allow the current present during such an event to pass through the device, thereby allowing unlimited generation and movement and eliminating the possibility of preventing the current level from rising and , therefore, temperature. This problem leads directly to uncontrollable high temperature results; In the absence of any internal means to prevent such a situation, the likelihood of fire and eventual burning and destruction of the device is generally imminent. Additionally, the current path (direction of charge) in a standard pantograph remains fairly static both before and during a short-circuit event, essentially exhibiting the same potential movement of electrical charge as would be expected when moving from cathode to anode and then horizontally along pantograph in a certain direction. However, during a short circuit, this current path cannot prevent or at least limit or delay such charge movement, allowing, in other words, uncontrolled rapid discharge throughout the battery. Combined with the high temperature associated with such rapid discharge, the catastrophic problems noted above (fires, explosions, etc.) occur.

In contrast, and again highly unexpected and counterintuitive for typical lithium battery structures and configurations, at the very least, use of the current collector of the present invention results in sensing extremely high current densities (due to the reduced thickness of the conductive element) and preventing movement charge (for example, lack of charge direction) in the event of a short circuit. In other words, with the particular design limitations inherent in the current collector component disclosed herein, the current density

- 6 043346 increases to such an extent that the resistance level causes an extremely high but contained high temperature associated with a short circuit. Thus, this level of resistance causes the conductive material (such as aluminum and/or copper, given by way of example only) to accept a short circuit charge, but due to the structural formation disclosed herein, the conductive material immediately responds to such high temperature, localized charge . In combination with other structural features of such a current collector component, namely the virtual absence of dimensionally stable polymer material in contact with such a layer of conductive material, the conductive material instantly oxidizes at the charge point on it, leaving, for example, aluminum oxide or copper oxide, both of which are non-conductive materials. With such instantaneous formation of non-conducting material, the short-circuit charge appears to dissipate as there is no direction for it to move. Thus, thanks to the current collector just described, the occurrence of an internal short circuit causes the current to cease immediately, effectively using the immediate result of the high temperature from such a short circuit to create a barrier to further movement of charge. Essentially, the absence of additional current in the entire enclosure of the energy storage device (under short circuit conditions, of course) dampens such an unwanted event to such an extent that the short circuit is completely eliminated, thereby eliminating the occurrence of runaway current or high temperature, and possibly Most importantly, the pantograph remains suitable for its original and protective purposes because the localized non-conductive material present does not cause any noticeable reduction in current flow when the energy storage device (battery, etc.) is operating as intended. In addition, the relatively small area of formation of non-conductive material leaves a significant surface area, etc. on the pantograph for further use without any need for repair, replacement or other corrective action. It is necessary to provide for such a situation, which of course does not always occur, but in the absence of the specific precautions and corrections just disclosed, the likelihood of such a high temperature exposure and destruction event actually remains much higher than usually acceptable. Thus, the entire pantograph, due to its instability under short circuit conditions, becomes a two-dimensional electrical fuse, preventing the potentially dangerous high currents associated with short circuits by using the instantaneous effect of this high current to disrupt the pantograph's ability to conduct current at the point of the short circuit.

Such advantages are provided with respect to such a new susceptor, which can be achieved through a number of different alternatives with similar end results. In any of these alternative configurations, such a current collector as described herein would appear to function as an internal fuse in the target energy storage device (eg, lithium battery, capacitor, etc.). However, in each example (alternative) there is a current collector including a polymer layer that is metalized on one or both sides thereof, with at least one metalized side in contact with the anode or cathode of the target energy storage device. One alternative then is for the total thickness of the entire metallized (coated) polymer pantograph substrate to be less than 20 µm, perhaps preferably less than 15 µm, and perhaps more preferably less than 10 µm, in each case with a measured resistance of less than 1 ohm/square , perhaps preferably less than 0.1 ohms/square and perhaps more preferably less than 50 ohms/square. Typical pantographs may have these characteristics, but are much heavier than those fabricated with reinforcing polymer substrates and do not have the safety benefits of the embodiment disclosed herein. For example, copper foil with a thickness of 10 microns can weigh 90 g/ ^m2 . However, the copper-clad foil can weigh as little as 50 g/m ² or even 30 g/m ² , or even less than 20 g/m ² , and in each case provide adequate electrical performance required for cell function. In this alternative structure, however, a very thin component also ensures that a short circuit occurs on the metal coating and, depending on overall resistance levels, generates, at the excessively high temperature caused by the surge of current during such a short circuit, a localized region of the metal oxide that immediately prevents further movement current from it.

Another possible alternative for such a new current collector is to provide a temperature dependent metallic (or metallised) material that either shrinks away from the heat source during a short circuit or is easily converted at a specific location in the material to a non-conductive material (such as aluminum oxide from the aluminum pantograph, as described above in a different way). Thus, the pantograph becomes thermally weak, unlike the aluminum and copper pantographs used today, which are quite heat resistant to high temperatures. As a result, a metal alloy with a lower intrinsic melting point can fail at lower short-circuit current densities, enhancing the safety benefits of the energy device described herein.

- 7 043346 lithium-based swarms. Another alternative is to make the susceptor by depositing a layer of conductive material, such as copper or aluminum, on fibers or films that exhibit relatively high shrink rates at relatively low temperatures. Examples thereof include thermoplastic films with melting points below 250 or even 200° C. and may include, but are not limited to, polyethylene terephthalate, nylon, polyethylene or polypropylene. Another possible way to achieve this result is to make a current collector by depositing a layer of conductive material, such as copper or aluminum, as above, on fibers or films that can swell or dissolve in the electrolyte when the materials are heated to relatively high temperatures compared to operating temperatures elements, but low compared to temperatures that can cause thermal runaway. Examples of such polymers that can swell in lithium-ion electrolytes include polyvinylidene fluoride and polyacrylonitrile, but there are other polymers known to those skilled in the art. Another way to implement this alternative process for creating an internal electrical fuse is to coat the substrate with a metal, such as aluminum, that can oxidize when heated, with an overall thickness of metal much thinner than that typically used for lithium batteries. For example, the very thin aluminum pantograph used today may be 20 µm thick. With a coating thickness of less than 5 microns, the chain will break faster, and with a coating thickness of less than 2 microns or even less than 1 micron, the chain will break even faster. However, another way to implement an open path is to provide a current collector with limited conductivity, which will degrade at high current densities surrounding the fault, similar to the degradation seen in commercially produced fuses today. This may be achieved by providing a current collector with a resistivity greater than 5 or 10 mOhm/square, or perhaps preferably greater than 20 mOhm/square, or perhaps more preferably greater than 50 mOhm/square. These measurements can be observed on one side or on both sides of the material coated on both sides. The different resistivity current collectors used may further be selected differently for batteries that are designed for high power, which can use relatively low resistance compared to cells designed for lower power and higher energy, and/or which can use relatively high resistance. Another way to implement a discontinuity in a conductive channel is to provide a susceptor that will oxidize to a non-conductive material at temperatures that are much lower than aluminum, allowing the susceptor to become inert in the short circuit region before the separator degrades. Some aluminum alloys oxidize faster than aluminum itself, and these alloys may cause the conductive path to degrade faster or at a lower temperature. As possible alternatives, any type of metal that is electrically conductive can be used in such a thin layer, including, but not limited to, gold, silver, vanadium, rubidium, iridium, indium, platinum and other metals (mainly due to the very thin layer it is possible to significantly reduce the costs associated with using such a metal without sacrificing conductivity, while still providing protection from likely thermal runaway during a short circuit or similar event). Layers of different metals, or even separate areas of metal deposited internally or as separate layered components, can also be used. Of course, also one side of such a coated susceptor substrate may include different types of metal than those used on the opposite side, and may also have relatively different layer thicknesses.

One way to improve the electrical properties of the cell would be to ensure that the coated current collector has two sides with a conductive coating, seemingly providing conductivity from the coating on one side to the coating on the other side. This result is not possible, for example, for an uncoated polymer film. However, it has been found that such bidirectional conductive capacity can be achieved in one non-limiting example using a nonwoven fabric including a certain percentage of conductive fibers, or a nonwoven fabric filled with conductive materials, or a nonwoven fabric made from a conductive material (such as carbon fibers). fibers or metallic fibers) or, as noted above, a nonwoven fabric containing fibers coated with a conductive material (eg, fibers with a metallic surface coating). Another type of new thin current collector material exhibiting top-down conductivity may be a film that is made conductive, for example by using an inherently conductive material (such as conductive polymers such as polyacetylene, polyaniline or polyvinylpyrrolidine) or by filling it with conductive material. material (such as graphite or graphene, or metal particles or fibers) during or after film production. Additionally, another possible double-sided thin current collector material is a polymer substrate with small perforated holes, the sides of which are plated with metal (aluminum or copper) during the metallization process. Such conductivity provided from one side to the other need not be the same as

- 8 043346 for conductive coatings.

Thus, such alternative configurations that appear to provide the same results and physical properties of the pantograph include the following:

a) the total thickness of the coated polymer substrate is less than 20 microns with a resistance of less than 1 Ohm/square,

b) the current collector contains a conductive material deposited on a substrate containing a polymeric material, and the polymeric material exhibits a heat shrinkage at 225°C of at least 5%,

c) the metallized polymer material of the current collector swells in the battery electrolyte, such swelling increasing as the polymer material heats up,

d) the total thickness of the conductive material of the current collector is less than 5 µm when applied to a polymer substrate,

e) the conductivity of the pantograph is from 10 to 1 Ohm/square and

f) the metallized polymer substrate of the current collector has a porosity of no more than 60%.

The use of any of these alternative configurations in an energy storage device with a separator exhibiting less than 5% thermal shrinkage after 1 hour at 225°C would also fall within the scope of the present invention. The general use (method of use) of this type of energy storage device (battery, capacitor, etc.) also falls within the scope of the present invention.

While the primary benefit of the present invention is increased safety for the cell, there are other benefits as mentioned above, including reduced weight of the entire energy storage device due to the reduced weight of metal in such susceptor components. Again, it is completely counterintuitive to use thin metalized polymer layers, especially those with poor dimensional stability properties, for current collectors inside such battery products. The current state of the art in this industry is that large quantities of actual metallic and/or insulating components are required to achieve the desired protection results (especially against possible short circuit events). Now it suddenly became clear not only that such a paradigm is incorrect, but also that an effective remedy for short circuit problems in lithium batteries, etc. consists of reducing, rather than increasing, the amount of metal, as well as combining it with thermally unstable base layers. Thus, quite unexpectedly, it became clear that thin metal layers in combination with such unstable base layers provide the ability to combat discharge events during short circuits and effectively stop them, with the overall effect being not only a much safer and more reliable result, but and in a significantly reduced overall weight and volume of such component parts. Thus, the unexpected benefits of improved properties with reduced weight and volume requirements for energy storage products (batteries, etc.) fit the industry much better than originally thought.

As further clarification, aluminum with a density of 2.7 g/cm ³ and a thickness of 20 microns would weigh 54 g/m ² . However, the same metal deposited with a thickness of 1 micron on a polypropylene film with a thickness of 10 microns (with a density of 0.9 g/cm ³ ) will weigh 11.7 g/m ² . This reduction in pantograph weight can reduce the weight of the entire energy storage device (e.g., battery), increase mobility, improve fuel consumption or electric range, and generally increase the value of mobile electric applications.

Additionally, due to the high strength of the films, the above example could also be made thinner, with a total thickness of 11 µm compared to 20 µm, for example, again reducing the volume of the element and thereby effectively increasing the energy density. Thus, a pantograph with an overall thickness of less than 15 microns, preferably less than 12 microns, more preferably less than 10 microns, and most preferably less than 8 microns can be manufactured and used for such purpose and function.

With a volume resistivity of aluminum of 2.7x10'8 ohm-m and copper of 1.68x10'8 ohm-m, it is possible to obtain a thin coating with a resistivity of less than 1 ohm/square or less than 0.5 ohm/square, or even less than 0.1 ohm /square, or less than 0.05 ohms/square. The thickness of these conductive coatings may be less than 5 microns, preferably less than 3 microns, more preferably less than 2 microns, perhaps most preferably even less than 1 microns. It is highly counterintuitive that when standard materials commonly used in the market contain 10 microns or more of metal, suitable performance can be achieved using much less metal. In fact, most of the metal present in typical storage devices is used to provide mechanical properties suitable for high-speed and automated processing. One of the advantages of the present invention is the use of a much lower density polymer material to provide mechanical properties, allowing the metal thickness to be reduced to a level where the safety of the element is increased due to the inability of the pantograph to support the dangerously high current densities that arise due to internal electrical shorts. short circuits and lead to thermal runaway, smoke and fire.

Moreover, these conductive layers can be formed by a plurality of layers. For example, the aluminum layer may be a base layer covered with a thin layer of copper. Thus, volumetric conductivity can be provided by aluminum, which is lightweight, inexpensive, and can be easily deposited by vapor deposition methods. Copper can provide additional conductivity and passivation to the anode without causing significant additional cost or weight. This example is provided merely for illustration, and those skilled in the art will be able to cite many other multilayer conductive structures, any of which are excellent examples of the present invention.

These thin metal coatings generally result in higher resistance than that observed in conventionally used aluminum or copper current collectors, which is a feature of the present invention. Such new suitable current collectors can be manufactured with a resistance greater than 10 mOhm/square, preferably greater than 20 mOhm/square, more preferably greater than 50 mOhm/square, and perhaps most preferably even greater than 100 mOhm/square.

Additionally, cells manufactured using the thermally weak susceptors described above may be even safer if the separator has high heat resistance, for example possibly exhibiting low shrinkage at high temperatures, including less than 5% shrinkage after exposure to 200°C for 1 h, preferably after exposure to 250°C for one hour and perhaps more preferably after exposure to 300°C for one hour. Existing separators are made of polyethylene with a melting point of 138°C and polypropylene with a melting point of 164°C. These materials exhibit >50% shrinkage at 150°C as shown in FIG. 2; this result is too high for use with a thin pantograph as now described herein. To solve this problem, it has been found that it is necessary to use certain separators that shrink less than 50% at 150°C, or even less than 30%, or less than 10%, as measured in accordance with NASA document TM-2010-216099, section 3.5. Even ceramic-coated cages exhibit significant shrinkage at relatively moderate temperatures, either collapsing completely or shrinking in excess of 20% at 180°C. Thus, it is desirable to use a separator that does not collapse during testing and does not shrink more than 20% when exposed to at least 180°C, more preferably more than 10%, when measured according to the same test standard. The most preferred embodiment would be to use a separator that shrinks less than 10% when exposed to temperatures of 200, 250 or even 300°C.

It is desirable for any of these metallized substrates to have a small thickness to help increase the energy density of the element. Any means can be used to achieve this thickness, including calendering, pressing, hot pressing, or even removing material from the surface so as to reduce the overall thickness. These thickness reduction processes can be performed before or after metallization. Thus, it is desirable to have an overall thickness of the metallized substrate of less than 25 microns, preferably less than 20 microns, more preferably less than 16 microns, and perhaps most preferably less than 14 microns. It has been established that commercially produced polyester films have a thickness of no more than 3 microns and even less than 1.2 microns. These types may serve as suitable substrates and provide an overall pantograph thickness of less than 10 μm, preferably less than 6 μm, and more preferably less than 4 μm. Such ultra-thin current collectors (with proper conductivity, as described above and throughout this document) can provide much higher energy densities with improved safety characteristics - a result that has until now remained unexplored.

It is also desirable for these metallized substrates to be lightweight. This can be achieved through the use of low density polymeric materials such as polyolefins or other low density polymers including polyethylene, polypropylene and polymethylpentene, given by way of example only. This can also be achieved by having an open cell structure in the substrate or even by using low basis weight substrates. Thus, the density of the polymer used in the support material may be less than 1.4 g/cm ³ , preferably less than 1.2 g/cm ³ , and perhaps more preferably less than 1.0 g/cm ³ . In addition, the basis weight of the support material may be less than 20 ^gsm , preferably less than 16 ^gsm , and perhaps most preferably less than 14 ^gsm . In addition, the basis weight of the metal-coated polymer material may be less than 40 ^gsm , preferably less than 30 ^gsm , more preferably less than 25 ^gsm , and perhaps most preferably less than 20 ^gsm .

Low weight can also be achieved using a porous polymer substrate. However, for these materials, the porosity should not be too high, as this will lead to low strength and high thickness, which actually defeats the purpose of the objectives. Thus, such base materials will have a porosity below about 60%, preferably below 50%, and perhaps more preferably below 40%. Since hard materials can be used for this type of metal-clad pantograph, there is no lower limit to porosity.

- 10 043346

High strength is required so that materials can be processed at high speeds in the battery. This can be achieved by using elongated polymers from either drawn fibers or uniaxial or biaxial stretched films.

As presented below in the description of the accompanying drawings, an energy storage device, whether a battery, a capacitor, a supercapacitor, or the like, is manufactured and thus provided in accordance with the present invention, wherein all of: at least one current collector that exhibits the properties associated with the absence of appreciable current movement after short circuit contact with the cathode, anode, or two separate current collectors in contact with both, the separator and the electrolyte, are located and sealed in a standard (suitable) energy storage device container. All the cathode, anode, container, electrolytes and in some cases separator components are mostly standard. However, as noted above, the current collector used in the present invention is not only new and unexplored in the art, but its use as an actual component of an energy storage device is counterintuitive. This is again described in more detail below.

As noted above, to reduce the likelihood of, if not completely prevent, thermal runaway within a battery cell (especially the lithium-ion rechargeable type, but other types are of course possible), a means is required that, in particular, causes some kind of short circuit in it primarily for a short period of time, with reduced residence time in or on the pantograph in question, and ultimately produces a resulting energy level of minimal joule values (i.e. less than 10, preferably less than 1, and most preferably less than 0.01 ). Then, as mentioned earlier, in such a situation where the electrical path is from the anode to the cathode and through the separator in the presence of an installed thin conductive current collector and a flammable organic electrolyte, it has been found that a thin current collector of low weight provides such a desirable result, particularly in terms of from the point of view of the dispersion of foreign charges on the surface of the current collector and the absence of a noticeable increase in temperature at which ignition of the electrolyte component would be inevitable. Surprisingly, without being tied to any specific scientific explanation or theory, it is believed that the conductivity property of the thin pantograph material allows electrical short circuit charges to just reach the thin conductive pantograph and immediately create a high energy short circuit event that reacts between the metal on the surface of the pantograph and the electrical charge itself, thereby creating a metal oxide that forms at that particular point on the surface of the pantograph. The metal oxide provides insulation for further electrical activity, and the applied current is instantly dissipated, leaving potential deformation within the current collector itself, but with the presence of the aforementioned metal oxide to protect against any further electrical charge activity at that particular location. In this way, the remainder of the pantograph remains intact and can provide the same capabilities as before, thereby further providing such protection against any other possible short circuits or the like. In the case of thermal runaway in prior art battery products, the anode, cathode, current collectors, and separator create an electrical path in which heat is generated and, for example, provides a spark to ignite the cell in response to a short circuit. The continued presence of ion-carrying flammable electrolytes may therefore result in significant hazards due to exposure to high temperatures associated with such unexpected electrical charges. Essentially, the heat generated in the prior art current collector causes initial electrochemical reactions in the electrolyte materials, which ultimately leads to uncontrolled ignition of the electrolyte materials themselves. Thus, the current collector of the present invention described herein is particularly valuable when used in battery cells containing such flammable electrolytes. By way of example, such electrolytes generally include organic solvents such as carbonates, including propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate and dimethyl carbonate, and others. These electrolytes are usually present in the form of mixtures of the above materials, possibly with other solvent materials, including additives of various types. These electrolytes also contain a lithium salt component, an example of which is lithium hexafluorophosphate, LiPF ₆ . Such electrolytes are preferred in battery production, but, as noted, they potentially contribute to hazardous situations. Again, the current collector of the present invention, in combination with other battery components, significantly and unexpectedly eliminates these problems.

One way in which the usefulness of this pantograph can be demonstrated is the following test. A current source with both voltage and current limitations 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 pantograph can be tested in two configurations. In the first configuration, a short strip of susceptor of known width is brought into contact with two metal connectors that provide contact across the entire width of the sample. The current source current limit can be increased to see if there is a capacity limit

- 11 043346 material to conduct a current that can be measured as the total current divided by the width to give a result in A/cm, which is herein referred to as the horizontal current density. The second configuration would be to make ground contact of the current source with one of the metal contacts across the entire width, and then touch the tip of the probe, approximately 0.25 mm ² , at a location along the pantograph strip. If the current is too large, it will cause the local area to burn out and no current will flow. If the current is not too large for the pantograph, then full current will flow up to the limit of the current source. The result is a current limit in A/mm ² , which is referred to herein as the vertical current density. Thus, a pantograph that can achieve high current in both configurations would be similar to that in the prior art, and a pantograph that can support horizontal current in full-width contact but cannot support similar vertical current in point contact would be an example of the described in the present invention document.

For example, it may be desirable for a susceptor to be capable of supporting a horizontal current density of 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 pantograph that can support the above horizontal current density, it would be desirable not to maintain a vertical current density of 0.1 A/ ^mm2 or 0.5 A/ ^mm2 or 1 A/ ^mm2 or 2 A/ ^mm2 . or even 5 A/mm ² .

As mentioned above, lithium-ion battery cells also typically have a tab welded inside them to connect the internal components, particularly the current collectors, together to connect to the tab terminal for the purpose of transferring charge to an external source. In this situation, for very thin types of pantographs, it is critical that the reed lead effectively contacts the internal foil pantographs and remains sufficiently in place to also contact the external source. Additionally, due to the effectiveness of the aforementioned surprisingly good thin film current collectors in providing the necessary operations of the battery cell itself, as well as the ability to provide internal fuse characteristics to prevent runaway current during a possible problem (dendrite formation, etc.), such a tab should not demonstrate any degree of bias or ineffectiveness to combat the same potential runaway charge problems. In other words, the effectiveness of the internal fuse's results should not be reduced or impaired by problems with the reeds. Surprisingly, it has been found that such desirable characteristics are acceptable for such reed components.

Thus, by now it has become clear that thin film pantographs actually provide efficient and strong welding of the tongue to them with the ability to actually provide conductivity on both sides of the film. The tongue itself is actually thicker than each individual pantograph, and when in contact with each other, the weld can be made to a depth that partially passes through the tongue material, depending on the shape and depth of the weld itself. However, an unexpected result is that the weld may actually pass through the tongue in a thin stream or similar formation, thereby allowing conduction through such weld material to the tongue. This creates a limited, albeit effective, conduction path to not only provide the necessary conductivity from the weld to the tongue (and then from the cell body to an external source), but also to provide a means of limiting the actual current and temperature generated by such conductivity channel at each location of the weld. This result allows the aforementioned control of runaway conduction from metallized film pantographs in the event of a short circuit (dendrite formation, etc.) since the electrical charge will stop at the actual surface of the pantograph and no other path for runaway charge is provided. Thus, welds can be made along the length of the reed component running along the pantograph, for example, in numbers of up to five, evenly spaced from each other, which provides effective conduction from the foil pantograph(s) to the tab through the battery body to an external source. Thus, the limited number of welds also reduces the number of possible runaway charge sites; Even though each of these sites has a limited current intensity, in some situations the current levels are certainly increased in the presence of many such sites. However, for high-power or high-current batteries, the number of welds per tab may be increased to accommodate the high current required for the battery to be effective in the application. In this case, a larger number of welds may be required, perhaps up to 10, 20 or even 50 welds per tongue. In rare cases, very high power or very high current components may require even more than 50 welds. Welded seams provide basic strength and also prevent tongue movement during use. Stability and rigidity are necessary to ensure proper operation of the battery as a whole. Confined welds do provide a level of reliability in this regard, while adding tension tape on top of the pantograph films also helps protect against such potential problems.

- 12 043346

In practice, thin film current collectors are surprisingly well suited for preventing runaway charges during a short circuit. However, the need for the reed terminals to be in sufficient contact with such pantographs to provide effective conduction outside the battery cell requires structural conditions that allow such thin film pantographs to be used with standard reed components. As noted above, it has proven difficult to ensure that both the current collector film(s) and the tabs with appropriate welds can be properly sized to effectively attach and contact them to efficiently pass electrical current during battery operation, while still providing a suitably low runaway charge probability. especially taking into account the specific and accepted in the field of technology today thick monolithic components of pantographs. This unexpectedly efficient result, especially taking into account the characteristics of the reed contact and its tensile strength determined as above, is consistent with an all-lithium-ion battery, which can have less weight or greater internal capacity for other components, without compromising the battery's energy production when while providing complete protection against uncontrolled charges during short circuit events.

These lithium-ion battery thin films may require certain unique processing steps due to their unique properties. However, many processing steps that are well known in the art can also be used. In general, a method for producing a lithium-ion battery with films of the present invention comprises the steps of:

a) Provide an electrode having at least one metallized substrate coated with an ion storage material;

b) Provide a counter electrode;

c) Layers of an electrode and a counter electrode are applied opposite each other, and a separator component is placed between the electrode and the counter electrode;

d) Provide a housing material including an electrical contact component, wherein the contact includes a portion present within the housing material and a portion external to the housing material;

e) Electrically connecting the electrical contact to the metallized substrate;

f) Introduce at least one liquid electrolyte containing ions into the housing material and

g) The housing material is sealed.

The metallized substrate can be any substrate described within the scope of the present invention.

The ion storage material may be, for example, a cathode or anode material for lithium-ion batteries, as is well known in the art. Cathode materials may include lithium cobalt oxide LiCoO2, lithium iron phosphate LiFePO ₄ , lithium manganese oxide LiMn ₂ O ₄ , lithium nickel manganese cobalt oxide LiNi _x Mn _y Co _z O2, lithium nickel cobalt aluminum oxide LiNi _x CO _y Al _z O2 or other mixtures of the above and other materials known in the art. Anode materials may include graphite, lithium titanate Li ₄ Ti ₅ Oi2, hard carbon, tin, silicon, or mixtures of these or other materials known in the art. Additionally, the ion storage material may include materials used in other energy storage devices such as supercapacitors. In such supercapacitors, ion storage materials will include activated carbon, activated carbon fibers, carbide-based carbon, carbon airgel, graphite, graphene, and carbon nanotubes.

The coating method may be any coating method generally known in the art. Knife over roll and slot die technologies are widely used plating methods for lithium-ion batteries, but other methods, including chemical plating, can also be used. In the coating process, the ion storage material is typically mixed with other materials, including binders such as polyvinylidene fluoride or carboxymethylcellulose, or other film-forming polymers. Other additives to the mixture include carbon black and other conductive additives.

Counter electrodes include other electrode materials that have different electrochemical potentials than ion storage materials. In general, if the ion storage material is a lithium ion anode material, the counter electrode will be made of a lithium ion cathode material. In the case where the ion storage material is a lithium ion cathode material, the counter electrode may be a lithium ion anode material. In the case where the ion storage material is a supercapacitor material, the counter electrode may be made from any supercapacitor material, or in some cases from a lithium ion anode or cathode material. In each case, the counter electrode will include an ion storage material deposited on a current collector material, which may be a metal foil or a metallized film of the present invention.

- 13 043346 teniu.

In the layering process, a counter electrode layer is applied to the electrode of the invention, with the electrode materials facing each other and a porous separator located between them. As is widely known in the art, the electrodes can be coated on both sides, the stack of electrodes being formed by the electrode of the present invention and counter electrodes, between which a separator is alternately located. Alternatively, as is also known in the art, strips of electrode materials can be stacked as above and then wound into a cylinder.

Packaging materials may include rigid packages such as metal cylindrical containers, flattened hard cases, or plastic bags. In each case there must be two means of making electrical contact through the housing which can be held at different voltages and which can conduct current. In some cases, one part of the housing itself forms one means, and the other is another part of the housing that is electrically isolated from the first part. In other examples, the housing may be non-conductive, but may have two metal conductors, often called tabs, extending from it.

Connection of the means for making electrical contact to the metallized substrate may be accomplished by commonly used methods such as welding, taping, clamping, staples, riveting, or other mechanical means. Since the metal of the metallized substrate can be very thin, direct contact is typically required to provide a interface region that allows large current to flow, which provides a large surface area between the means for making electrical contact through the housing and the metallized substrate. To carry sufficient current, this surface area must be greater than 1 square millimeter (10 ^-12 square meters), but may need to be higher than 3 square millimeters or even 5 square millimeters, or more preferably 10 square millimeters.

The liquid electrolyte is usually a combination/mixture of a polar solvent and a lithium salt. Commonly used polar solvents include, as noted above, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, but other polar solvents can be used, including ionic liquids or even water. Lithium salts commonly used in this industry include, but are not limited to: LiPF ₆ , UPF ₄ , UBF ₄ , LiClO ₄ and others. The electrolyte may also contain additives that are known in the art. In many cases, electrolytes can be flammable, and the protective properties of the metallized substrate current collectors of the present invention may be suitable to prevent dangerous thermal runaway events that result in fire and damage to both the cell and its surroundings.

Brief description of drawings

In fig. 1 shows the architecture of a wound cell, such as an 18650 cell, in accordance with the prior art.

In fig. 2 shows state-of-the-art shrinkage versus temperature that was obtained using dynamic mechanical analysis of several lithium-ion battery separators measured in accordance with NASA/TM-2010-216099, Procedures for Characterization and Evaluation of Battery Separators for Advanced Lithium-Ion Batteries. NASA's Battery Separator Characterization and Evaluation Procedures for NASA's Advanced Lithium Ion Batteries, the contents of which are incorporated herein by reference (see Section 3.5). In particular, first generation separators (Celgard PP, Celgard three-layer), 2nd generation separators (ceramic PE) and 3rd generation separators (Silver, Gold, Silver AR) are included.

In fig. 3A shows a cross-sectional scanning electron microscope (SEM) micrograph of a prior art stack element that has passed a nail penetration test. The layers are composed of aluminum and copper, as shown by BEI (backscattered electron imaging). The nail is located vertically on the left side. In each case, the aluminum layer came away from the nail, leaving behind a crust of aluminum oxide, i.e. insulator.

In fig. 3B shows an enlargement of one of the layers from the image of FIG. 3A level of technology. This figure shows a close-up view of the aluminum oxide layer and shows that the separator has not shrinked at all and is still separating the electrodes all the way to the edge.

In fig. 4 shows an invention in which a thin layer of conductive material is on the outside and the central substrate is a layer that is thermally unstable at temperatures required for thermal runaway. This substrate may be a fusible layer, a shrink layer, a dissolving layer, an oxidizing layer, or another layer that will exhibit thermal instability at temperatures ranging from 100 to 500°C.

In fig. 5A shows a thick aluminum current collector, typically 12-20 µm thick in accordance with the prior art.

In fig. 5B shows the present invention comprising a 14 µm thick substrate with 1 µm of aluminum on each side. The pantograph of the present invention is not capable of carrying the high currents associated with a short circuit, while the thick pantographs of the prior art are capable and do so.

In fig. 6 and 6A show images of Comparative Examples 1-2, each of which was obtained after touching the tip of a hot soldering iron. Comparative examples do not change after being touched with a hot soldering iron.

In fig. 7, 7A and 7B show images of examples 1-3, each of which was obtained after touching the tip of a hot soldering iron. All examples 1-3 demonstrate the shrinkage described within the scope of the present invention for substrates to be metallized.

In fig. 8, 8A and 8B show images of examples 4-6, each of which was obtained after touching the tip of a hot soldering iron. Example 4 demonstrates the shrinkage described within the scope of the present invention for substrates to be metallized. Example 5 contains a fiber that dissolves in lithium ion electrolytes when heated. Example 6 is an example of a heat-resistant substrate that would require a thin conductive layer to function in accordance with the present invention.

In fig. 9, 9A and 9B show cross-sectional SEM photographs at various magnifications, one of which shows the metallized surface of one possible embodiment of the single current collector described in Example 9. The metal is clearly much thinner than the original substrate, which was 20 µm thick.

In fig. 10 and 10A are optical micrographs of Comparative Examples 3 and 4 after a short circuit, showing ablation of the area around the short circuit but without a hole.

In fig. 11 and 11A show optical micrographs of two regions from Example 14 after a short circuit, showing clear holes in the material caused by the high short circuit current density.

In fig. 12 shows the size and shape of the pantograph used in the examples below.

In fig. 13 is a side perspective view of a single-layer pantograph with a welded tongue as one potentially preferred embodiment.

In fig. 14 is a side perspective view of a single layer pantograph with a taped tab as another potentially preferred embodiment.

In fig. 15 is a side perspective view of a single layer pantograph with a stapled tab as another potentially preferred embodiment.

In fig. 16 is a side perspective view of a single layer pantograph with a single curved fold and a taped tab as another potentially preferred embodiment.

In fig. 17 is a side perspective view of a single layer pantograph with double curved folds and a taped tab as another potentially preferred embodiment.

In fig. 18 is a side perspective view of a single layer pantograph with two parallel welded tabs as another potentially preferred embodiment.

In fig. 19 is a side perspective view of a single layer pantograph with a single folded weld tab as another potentially preferred embodiment.

In fig. 20 is a side perspective view of a single layer pantograph with double curved folds and a welded tab as another potentially preferred embodiment.

In fig. 21 is a side perspective view of a plurality of single layer pantographs, each having a double fold and a welded tab, as another potentially preferred embodiment.

In fig. 22 is a side perspective view of a plurality of single-layer pantographs, each having a double fold and two opposing welded tabs, as another potentially preferred embodiment.

In fig. 23 is a side perspective view of a plurality of single-layer pantographs contacting a plurality of Z-folded clamping tabs, as another potentially preferred embodiment.

Carrying out the invention

The following description and examples merely represent potential embodiments of the present invention. Based on the claims below, those skilled in the art will clearly understand the scope of such an invention and its breadth.

As noted above, the present invention represents a significant shift and is contrary to all previous concepts and remedies undertaken in the field of lithium batteries (and other energy storage devices). On the contrary, the new devices described herein provide a number of useful results and properties that have not yet been explored or even expected in the art. However, first, for purposes of comparison, it is important to note the stark differences between the devices of the prior art and the devices that are disclosed and extensively covered herein.

Examples of a short circuit event

Comparative example 1.

The lithium iron phosphate battery cathode was obtained from GB Systems in China. An aluminum tongue was removed as an example of a commercially available pantograph, and the thickness, areal density and resistance were measured and are shown in Table 1. 1 below. The aluminum foil was then touched with a hot soldering iron for 5 seconds and the temperature was measured to be between 500 and 525°F using an infrared thermometer. No effect was observed from touching the soldering iron to the current collector. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 6. In FIG. 5 shows a conventional current collector in such a comparative battery.

Comparative example 2.

The anode for the lithium iron phosphate battery was obtained from GB Systems in China. The copper tab was removed as an example of a commercially produced pantograph, and the thickness, area density and resistance were measured and shown in Table. 1 below. Then the copper foil was touched with a hot soldering iron in the same way as in example 1. No effect was observed from touching the soldering iron to the current collector. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 6. As in Comparative Example 1, FIG. Figure 5 shows the internal structure of such a battery. The thickness of the pantograph is important because it is a monolithic metal structure rather than the thin structure disclosed herein.

Example 1.

The polypropylene material for the lithium battery separator was obtained from MTI Corporation. The material was manufactured by Celgard under product serial number 2500. Thickness, areal density and resistance were measured and are shown in Table 1. 1 below. The separator was then touched with a hot soldering iron in the same way as in example 1. Touching the thermometer to the pantograph created a small hole. The diameter was measured and indicated in the table. 1. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 7.

Example 2.

The ceramic coated polyethylene material for the lithium battery separator was obtained from MTI Corporation. Thickness, areal density and resistance were measured and shown in Table. 1 below. The separator was then touched with a hot soldering iron in the same way as in example 1. Touching the soldering iron to the pantograph created a small hole. The diameter was measured and indicated in the table. 1. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 7A.

Example 3.

The ceramic coated polypropylene material for the lithium battery separator was obtained from MTI Corporation. Thickness, areal density and resistance were measured and shown in Table. 1 below. The separator was then touched with a hot soldering iron in the same way as in example 1. Touching the soldering iron to the pantograph created a small hole. The diameter was measured and indicated in the table. 1. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 7B.

Example 4.

The aluminized biaxially oriented polyester film was obtained from All Foils Inc. and is intended for use in helium-filled party balloons. The aluminum coating holds the helium longer, giving party balloons a longer shelf life. Thickness, areal density and resistance were measured and shown in Table. 1 below. The film was then touched with a hot soldering iron in the same way as in example 1. Touching the soldering iron to the pantograph created a small hole. The diameter was measured and indicated in the table. 1. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The photograph taken is shown in Fig. 8. Compared with the commercially available aluminum pantograph of Comparative Example 1, this material is 65% thinner and 85% lighter, and also shrinks when heated, which in a lithium ion cell with an internal short circuit would cause the internal short circuit to cease .

Example 5.

A commercial Dreamweaver Silver 25 lithium-ion battery separator was obtained. It is made from a mixture of cellulose and polyacrylonitrile nanofibers and polyester microfibers in

- 16 043346 paper production process and calendered to a small thickness. The separator was then touched with a hot soldering iron in the same way as in example 1. Touching the thermometer to the pantograph did not result in the formation of a hole. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. Compared to the state of the art, i.e. Comparative Examples 3-5, these materials have the advantage that they do not melt or shrink when heated, and therefore in an internally shorted lithium ion battery they will not create a uniformly larger internally shorted area. This is shown in Fig. 8A.

Example 6.

A commercially available prototype of the Dreamweaver Gold 20 lithium-ion battery separator has been produced. It is made from a mixture of cellulose and para-aramid nanofibers and polyester microfibers during the papermaking process and calendered to a small thickness. The separator was then touched with a hot soldering iron in the same way as in example 1. Touching the thermometer to the pantograph did not result in the formation of a hole, as shown in Fig. 8B. Thickness, areal density and resistance were measured. The material was placed in an oven at 175°C for 30 minutes and shrinkage was measured. The advantages of this separator compared to separators from the prior art are the same as in example 2.

Table 1

Example Material Thickness Surface density Resistance Shrinkage (175°C) The size of the hole made by the tip of the soldering iron Wed. example 1 Aluminum 30 µm 80 g/ ^m2 <0.1 mOhm/square 0% No hole Wed. example 2 Copper 14 µm 125 g/ ^m2 <0.1 mOhm/square 0% No hole Example 1 RR 24 µm 14 g/ ^m2 Infinite Melted 7.5 µm Example 2 PP ceramics 27 µm 20 g/ ^m2 Infinite Melted 2 µm/1 µm Example 3 PE ceramics 27 µm 20 g/ ^m2 Infinite Melted 5 µm/2 µm Example 4 Aluminized PET 13 µm 12 g/ ^m2 6.3 ohms/square 33% 2 µm Example 5 Fiber blend 27 µm 16 g/ ^m2 Infinite 2% No hole Example 6 Fiber blend 23 µm 16 g/ ^m2 Infinite 0% No hole

Comparative Examples 1, 2 are existing susceptor materials that exhibit very low resistance, high areal density, and no either hot tip reaction or shrinkage at 175°C.

Examples 1-3 are materials that have infinite resistance, have low surface density and melt when exposed to a temperature of 175°C or the tip of a hot soldering iron. They are excellent substrates for metallization according to the present invention.

Example 4 is an example of an aluminized polymer film that exhibits moderate resistance, low areal density and shrinks when exposed to a temperature of 175°C or the tip of a hot soldering iron. This is an example of a composite film of a potential cathode current collector according to the present invention. In practice, and as shown in additional examples, it may be desirable to provide a higher level of metal coating for higher power batteries.

Examples 5, 6 are materials that have infinite resistance, low surface density, but have very low shrinkage when exposed to a temperature of 175°C or the tip of a hot soldering iron. These are examples of the polymer substrate of the present invention where the thickness of the metallized coating is sufficiently small that the metallized coating fails under high current conditions associated with a short circuit. In addition, cellulose nanofibers and polyester microfibers will oxidize, shrink, and ablate at temperatures much lower than the melting temperatures of metal current collectors currently used in practice.

Example 5 is further made from a fiber, polyacrylonitrile, which swells when exposed to traditional lithium carbonate electrolytes, which is also an example of a polymer substrate of the present invention, if the swelling would increase with heating and create cracks in the metallized coating that would interrupt the conductive channel, thereby increasing the safety of the cell by eliminating or significantly reducing the uniform conductive channel of the current collector under the influence of heat inside the battery.

Example 7.

The material used in Example 5 was placed in the deposition position of an MBraun vacuum deposition system using an intermetallic crucible and aluminum pellets. The camera was

- 17 043346 evacuated to 3x10 ^-5 mbar. The power was increased until the aluminum melted, and then the power was adjusted so that the deposition rate was 3 angstroms/s. Deposition was carried out for 1 h with four samples rotating on the deposition plate. The process was repeated three times, resulting in a total deposition time of 4 hours. The weight, thickness and resistance of the samples were measured (constant current and 1 kHz, 1 inch strip measured between electrodes 1 inch apart) and are shown in Table 1. 2 below. Point resistance was also measured using a Hioki 3555 Battery HiTester at 1 kHz with probe tips 1 inch apart. The weight of added aluminum was calculated by dividing the weight added during the process by the area of the sample. It is divided by the density of the material to obtain the average coating thickness.

Example 8.

The non-woven polymer backing was made by taking polyethylene terephthalate microfibers with a flat cross section and making hand sheets of 20 ^gsm using the Tappi T206 process. These hand sheets were then calendered at 10 m/min, 2000 psi using hardened steel rolls at 250°F. This material was metallized according to the process of Example 7, and the same measurements were made as shown in Table 1. 8.

Example 9.

The material of Example 5 was applied according to the process of Example 7, except that the coating was performed at a setting of 5 angstroms/s for 60 minutes. The samples were turned over and the reverse side was coated in the same manner. Scanning electron microscopy (SEM) images of both the surface and cross-section of these materials were obtained, and these images are shown in FIG. 9, 9A and 9B.

Example 10.

The materials were prepared according to the procedure of Example 9, except that deposition on each side lasted only 20 minutes.

Example 11.

The polymer substrate of Example 8 was prepared, except that the sheets were not calendered. Aluminum deposition occurs at a rate of 5 angstroms/s for 20 minutes on each side. Because the materials have not been calendered, the porosity is very high, giving very high resistance values when the coating is thin. A comparison of Example 11 with Example 8 shows the unexpectedly high benefits of calendering.

table 2

Sample Added weight DC resistance Resistance at 1 kHz Point resistance at 1 kHz Average coating thickness Unit g/m ² Ohm/square Ohm/square Ohm Micron Example 7 3.5 0.7 0.5 0.1 1.3 Example 8 2.0 7 7 0.4 0.7 Example 9 2.2 0.2 0.8 Example 10 0.8 1.7 o, s Example 11 0.8 100 o, s

Example 12.

The aluminum-coated polymer substrate of 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 coating weight was 12.7 mg/cm ² with a thickness of 71 microns. This material was cut to fit the 2032 disk cell and bonded to a graphite anode deposited on a copper foil current collector (6 mg/ ^cm2 , 96.75% graphite (BTR), 0.75% carbon black, 1.5% SBR and 1% CMC). A single-layer disk cell was fabricated by placing an anode, separator (Celgard 2320) and NCM coated material into the cell, pouring electrolyte (60 µL, 1.0 M LiPF6 in EC:DEC:DMC=4:4:2 vol+2 wt). % VC) and sealing the element by compressing the shell. To obtain adequate conductivity, a portion of the aluminum-coated polymer substrate of Example 9 was not coated with cathode material and folded to provide contact with the disk element shell, thereby completing the conduction channel. The cell was formed by charging at a constant current of 0.18 mA to 4.2 V, then at a constant voltage (4.2 V) until the current dropped to 0.04 mA. The cell was switched three times between 4.2V and 3.0V at 0.37mA and showed an average discharge capacity of 1.2mAh.

Example 13.

The element was manufactured following the procedure and materials of Example 12 except that Dreamweaver Silver 20 was used as the separator. The element was

- 18 043346 is formed by charging at a constant current of 0.18 mA to 4.2 V, then at a constant voltage (4.2 V) until the current drops to 0.04 mA. The element was switched three times between 4.2 and 3.0 V at

0.37 mA and showed an average discharge capacity of 0.8 mAh. Thus, in this and the previous examples, the working rechargeable lithium-ion cells were made using aluminum less than 1 micron thick.

Comparative example 3.

The aluminum tongue of Comparative Example 1, measuring approximately 2 cm x 4 cm, was connected to the current source ground via a metal connector in full width contact with the sample. The voltage limit was set to 4.0 V and the current limit to 1.0 A. The probe, connected to the high voltage output of the current source, first touched a metal connector in full width contact with the sample, and then touched an aluminum tab numerous times. causing a short circuit at 1.0 A. The tip of the probe had an area of approximately 0.25 mm ² . When contact was made across the entire width, the current flowed normally. When the probe initially touched the tongue, sparks were generated, indicating a very high initial current density. The resulting defects in the pantograph only sometimes resulted in the formation of holes, and in other cases ablation occurred but the pantograph remained intact. In all cases the circuit remained closed at 1.0 A. A micrograph taken of the removed defect without a hole is shown in FIG. 10. The experiment was repeated with the current source limit set to 5.0 A, 3.0 A, 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 as when making contact across the entire width of the pantograph, and when using a point probe with a tip size of approximately 0.25 mm ² .

Comparative example 4.

The copper tongue of Comparative Example 2 with similar dimensions was tested in the same manner as Comparative Example 3. Current flowed normally when in full width contact. When the probe initially touched the tongue, sparks were generated, indicating a very high initial current density. The resulting defects in the pantograph only sometimes resulted in the formation of holes, and in other cases ablation occurred but the pantograph remained intact. In all cases, the circuit remained closed at a current of 0.8 A. A micrograph taken of the removed defect without a hole is shown in FIG. 10A. The experiment was repeated with the current source limit set to 5.0 A, 3.0 A, 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 as on contact across the entire width of the pantograph, and when using a point probe with a tip size of approximately 0.25 mm ² .

Example 14.

The inventive aluminum-coated polymer substrate material of Example 7 with similar dimensions was tested using the same method as Comparative Examples 34. When contacted across the entire width, current flowed normally. In each case of direct contact of the probe with the current collector of the invention, the resulting sparks were much smaller, and the current stopped flowing after the initial sparks, leaving an open circuit. In all cases, the resulting defect was a hole. Photomicrographs of several example holes are shown in FIG. 11 and 11A. The experiment was repeated with the current source limit set to 5.0 A, 3.0 A, 0.6 A, 0.3 A and 0.1 A, and in all cases the result was a continuous flow of current at contact across the entire width of the connectors , and the absence of current flowing in the example of the present invention in direct contact from the probe to the exemplary pantograph of the present invention.

The key to the present invention is that when subjected to a short circuit, as in Comparative Examples 3-4 and Example 14, according to the prior art the result is a continuing short circuit, whereas according to the material of the present invention the result is an open circuit, in which no continuous current flows (i.e., there is no noticeable movement of current). Thus, a short circuit in accordance with the prior art can and does generate heat that can melt the separator, dissolve the SEI layer and cause thermal runaway of the cell, thereby igniting the electrolyte. The open circuit current collector of the present invention will not generate heat and thus provides an element that can withstand the effects of internal short circuits without allowing thermal runaway and resulting smoke, heat and combustion.

Examples 15 and 16 and comparative examples 5 and 6.

Two metallized films were produced on 10-micron polyethylene terephthalate film using roll-to-roll technology. In this technique, a roll of film is placed in a vacuum metallization machine (an example of which is the TopMet 4450, available from Applied Materials) and the chamber is evacuated to a low pressure. The roll was passed over heated boats containing molten aluminum at a high speed, for example 50 m/min. Above the heated boats containing molten aluminum is a plume of aluminum gas, which is deposited on the film, the rate of deposition being controlled by the speed and temperature of the aluminum. The roll, approximately 500 m long and 70 cm wide, was produced in

- 19 043346 many passes until the aluminum coating has reached approximately 300 nm. The coating process was repeated to coat the other side of the film, and the resulting product is referred to herein as Example 15 (wherein the current collector of the present invention shown in FIG. 4 is the one used in this example). Thus, Example 16 was made in the same manner, except that the metal in the boat was copper (whereas FIG. 5B shows the current collector used in this design of the present invention). The basis weight, thickness and conductivity of each film were measured and are presented in the table below. 3. The coating weight was calculated by subtracting 13.8 g/ ^m2 , which corresponds to the base weight of 10 micron polyethylene terephthalate film. The design thickness of the coating was determined by dividing the weight of the coating by the density of the materials (2.7 g/cm ³ for aluminum, 8.96 g/cm ³ for copper), assuming uniform coating on each side.

Comparative Example 5 is a commercially available aluminum foil with a thickness of 17 μm. Comparative Example 6 is a commercially available copper foil with a thickness of 50 μm. Comparative Example 7 is a commercially available copper foil with a thickness of 9 μm.

Table 3

Sample Base weight Cover weight Thickness DC resistance Design coating thickness Unit g/m ² g/m ² Micron Ohm Micron Example 15 17 3 AND 0.081 0.5 Example 16 24 10 AND 0.041 0.5 Comparative Example 5 46 17 Comparative Example 6 448 50 Comparative example 7 81 9

Example 15, Example 16, Comparative Example 5 and Comparative Example 6 were further tested for their ability to tolerate very high current densities. A test device was fabricated that held a 0.51 mm radius polished copper wire (24 gauge American Wire Gauge (AWG)) in contact with the pantograph film or foil. The test film or foil was grounded using an aluminum contact in contact with the test film or foil with a contact area of >1 square centimeter. The probe was connected in series with a high power 400 W 0.335 ohm resistor and connected to a Volteq HY3050EX power supply set to monitor current. The pantograph to be measured was placed in the setup with the polished wire in contact with the surface of the pantograph at zero input current. The current was increased in 0.2 ampere steps and held for 30 s for each step while the voltage across the resistor was measured. When the voltage dropped to zero, meaning no more current was flowing, the sample had failed. Example 15, Example 16, Comparative Example 5, and Comparative Example 6 were each tested. Example 15 failed at 7 A (average of the two measurements). Example 16 failed at 10.2 A (average of two measurements). Neither Comparative Example 5 nor Comparative Example 6 failed at currents below 20 A. Both Example 15 and Example 16 were found to have holes in the pantograph with a radius > 1 mm, while neither Comparative Example 5 or 6, no damage to the foil was detected. In this example test, it would be advantageous to have a current collector that cannot carry more than 20 A, preferably more than 15 A, or more preferably more than 12 A.

In another test designed to simulate the use of these current collectors of the invention as a tongue connecting the electrode stack of a cell to the electrical devices being used (inside or outside the cell), Examples 15 and 16 and Comparative Examples 5 and 6 were subjected to a current load test along the strip. To prepare the specimens for testing, the pantographs were cut to the shape shown in FIG. 12, and consisted of a strip of material measuring four centimeters by centimeter (4 cm x 1 cm), with the ends of the strip ending in truncated right-angled isosceles triangles with a side of 4 cm. Each of the triangles of the test sample was in contact through an aluminum element with a contact surface area > 1 cm. One side was connected through a 400W, 0.335 ohm resistor and this circuit was connected to a Volteq HY3050EX power supply. Voltage was measured across resistors to measure current, and the element was shown to fail when this voltage dropped to zero. For each test, the cell was connected to a power supply set to zero current, which was then increased in 0.2 A increments and held for 30 s at each new voltage until the sample failed and the current flow dropped to zero. The test was organized

- 20 043346 is designed in such a way that it is possible to measure metallized pantographs using a contact either on one side or on both sides of the metallized pantograph. Failure currents are shown in the table below. 4. For materials tested in a 4 cm x 1 cm strip, it was advantageous to provide an internal fuse, limiting the amount of current that could flow to less than 20 A, or preferably less than 15 A, or more preferably less than 10 A, for each case with one-way or two-way contact.

Table 4

Sample Unit Example 15 Example 16 Failure voltage for single-sided contact V 2.7 24 Failure voltage for two-way contact V 4.5 10 Comparative Example 5 No failure below 20A No failure below 20A Comparative Example 6 No failure below 20A No failure below 20A

Examples 17-19 and comparative example 8.

The cells were prepared by depositing electrode materials onto standard foil current collectors and metallized PET film current collectors from Examples 15 and 16. NMC 523 cathode materials were prepared using NMC523 (97%) from BASF, carbon black (2%) and PVDF (1%) in NMP solvent and applied to an aluminum current collector (15 micron aluminum current collector) and example 15 at a base weight of 220 g/m ² , which corresponds to a cathode loading density of 3.3 mAh/cm ² . The anode materials were prepared by using BTR-918S graphite (94%), carbon black (5%) and PVDF (1%) in NMP solvent and applied to a copper pantograph (18 micron copper pantograph) with a density of 118 g/ ^m2 . which corresponds to an anode loading density of 4.0 mAh/cm ² . Four double-sided cathodes, three double-sided anodes, and two single-sided anodes were manufactured. They were stacked on top of each other using a Celgard 2500 separator to form small stacked cells, which were then filled with electrolyte and sealed to a design capacity of 1 Ah. Four types of cells were made from different combinations of foil materials, and the capacitance was measured at C/10 and C/5 (i.e. 0.1 A and 0.2 A). The cells were formed by charging at 100 mA to 4.2 V and holding at 4.2 V until the current dropped to 10 mA. The fully formed cells were then weighed and tested for capacity by discharging at C/10, then charging at C/10 and discharging at C/5. These results are shown in table. 5 below.

Table 5

Sample Cathode pantograph Anode pantograph Element weight Capacity C/10 Capacity C/5 Unit G mAh mAh Comparative Example 8 Aluminium foil Copper foil 27 924 615 Example 17 Example 15 Copper foil 26.8 1049 751 Example 18 Aluminium foil Example 16 24.7 1096 853 Example 19 Example 15 Example 16 24.7 1057 848

In summary, the above examples have been shown to demonstrate the desired thickness, metal plating and conductivity results required to prevent thermal runaway within an electrolyte-containing battery, thereby providing not only a much safer and more reliable type of battery, but also requiring much less heavy internal components than ever before, without compromising security, but in fact improving it.

As noted above, the ability to not only provide such a thin current collector (as an internal fuse within a lithium battery product), but also the necessary advantages of the tab structure to allow the generated voltage to be transferred beyond the battery cell in question, is at the core of the present invention. In addition, the ability to further utilize the above useful thin current collector structures allows for any number of innumerable configurations to be used within the battery product itself, potentially generating aggregate power levels in the presence of useful internal safety component(s). This is shown in more detail in FIG. 12-22.

In fig. 13 shows a single thin film tab/susceptor 600 with a metallized film layer 614 and a bottom non-metallic layer 616. Also provided is a conductive tab 610 (for connection to an external battery power transfer component) aligned perpendicular to the pantograph and connected thereto by welds 612.

In fig. 14 shows a similar pantograph 620, but with a tab 622 with a tape 624 connecting

- 21 043346 tongue 622 with pantograph 634 to ensure conductivity. As stated above, tongue/susceptor 620 has a metallized film layer 626 and a bottom non-metallic layer

632. A tape component 622 is provided on the outer surface 628 of the tongue and leads to a non-metallic pantograph layer 626, provided that the adhesive shear strength capability allows the tongue to remain suitably secured to provide conductivity.

In fig. 15 is another tab/pantograph 640, showing another method of connecting tab 642 to one thin pantograph 648 (with a metallized film layer 644 and an underlying non-metallic layer 650) by connecting the two components using conductive staples 646.

Such planar current collector structures allow for typical battery configurations with compact battery structures (such as those shown, for example, in FIG. 1). In fig. 16 shows a tab/susceptor 700 with one fold 710 and one tape tab 702 attached to a metallized film surface 712 (which covers, as above, a non-metallic layer 708). Thus, the current collector 704 with a single fold 710 results in the ability to increase power production within the battery cell, although at the cost of slightly increasing the size of the battery compared to a flat structure.

In fig. 17 shows a tongue/pantograph 720 with double folds 732 using the same thin pantograph structure 724. Thus, such double fold 732 further provides the ability to connect two sides 726, 728 of pantograph 724 that might otherwise be electrically insulated by a polymer film sandwiched between two electrically conductive layers. A tab 722 is attached to the surface 730 of the pantograph to provide conductivity through the double fold 732.

In fig. 18 also shows a flat tongue/susceptor 750 with a top surface 758 and a bottom surface 762 of the same type as above. In this example, the tongue 752, 754 is configured as two parallel structures in contact with both the top surface 758 and the bottom surface 760 of the pantograph 762. Such tongue 752, 754 includes welds 756 for connection with both surfaces 758, 760.

In fig. 19 shows a structure 780 similar to that shown in FIG. 16, but with a single folded tongue 794 that contacts both surfaces 788, 790 of the pantograph 792 through welds 786, with two elongated projections 782, 784 extending from the folded tongue 794.

In fig. 20 shows tongue 802 welded via welds 804 to double-pleated tongue/pantograph 800, thereby demonstrating the same ability to connect electrically insulated layers 808, 812 as discussed above with pantograph 806, but with safer welds 804 , which are more reliable and potentially more efficient for power transmission purposes.

In fig. 21 thus shows a composite tongue/multiple pantograph structure 820 comprising a plurality (in this case five) of such pantographs 826, 828, 830, 832, 834 with rounded double folds 856, as well as metallized film layers 858, 860, 862, 864, 866 and lower non-metallic layers 846, 848, 850, 852, 854 connected in series to further enable electrically insulated layers to be connected for conductivity through a single tab 822 with welds 824 connecting for conductivity to the upper pantograph 826 with rounded double folds. The 822 weld tongue also stays firmly in place for increased reliability.

A second opposing tongue 904 welded by welds 906 is shown in FIG. 22 having such an array of multiple pantographs 908, 910, 912, 914, 916 with multiple rounded folds 938. This tab/pantograph structure 900 allows for increased power production without the need to increase the weight or volume of the battery cell in question through two tabs 902, 904 configured and connected to two external pantographs 908, 916, as noted previously. The metallized film layers 940, 942, 944, 946, 948, as described above, are provided with opposing non-metallic layers 928, 930, 932, 934, 936, as in other similar examples of current collectors.

As shown in FIG. 23, as another non-limiting example of a tongue/pantograph structure 960, a tongue 962 with a plurality of Z-folds 972 is attached to a set of parallel flat thin pantographs 964, 966, 968, 970 (four in this case) (as described above), with In this case, the metallized film layers 974, 978, 982, 986 and the lower non-metallic layers 976, 980, 982, 984 are again provided to provide another method of generating total power in series, albeit with flat thin current collectors 964, 966, 968, 970 ( functioning as multiple internal fuses).

Therefore, such structures as shown in FIG. 13-23 allow for different external connections to the internal fuse components of a stand-up lithium battery.

Having described the invention in detail, it will be apparent that one skilled in the art

-

Claims (11)

technicians will be able to make changes and modifications thereto without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined only by the appended claims. CLAIM 1. 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 thin film current collector contacting at least one of the anode and the cathode, and at least one reed, attached to said at least one thin-film current collector, wherein: a) the tab is attached to the pantograph by means of a connecting means, wherein the connecting means is selected from the group consisting of adhesive tape, staples, conductive adhesives and clips; b) the connecting means is in electrical contact with the exposed surface of the tongue and the thin film pantograph; c) either an anode or a cathode is placed between at least a portion of the thin film current collector and the separator; d) the current collector contains a conductive material deposited on a substrate of non-conductive material; e) the pantograph ceases to conduct at the short-circuit contact point at the operating voltage of the energy storage device, and f) the voltage is at least 2.0 V. 2. The energy storage device according to claim 1, wherein said clamps clamp intermediate metal strips or z-folded metal strips. 3. The energy storage device according to claim 1, wherein the connecting means consists of 2-50 connections distributed throughout the current collector so as to ensure uniform flow of current from the electrode materials to the reed, respectively. 4. The energy storage device according to claim 1, wherein the separator is made of a polymer, non-woven material, fabric or ceramic. 5. The energy storage device according to claim 1, wherein the non-conductive material substrate is a polymer film. 6. The energy storage device according to claim 1, wherein the electrolyte is a flammable organic electrolyte. 7. The energy storage device of claim 1, wherein the tongue is a first tongue contacting an upper surface of the pantograph and a second tongue contacting a bottom surface of the pantograph, the first tongue and the second tongue being parallel. 8. The energy storage device of claim 1, wherein the tab is folded over the pantograph such that the first protrusion of the tab contacts the top surface of the pantograph and the second protrusion of the tab contacts the bottom surface of the pantograph, the first protrusion and the second protrusion being parallel. 9. An energy storage system comprising at least one energy storage device comprising an anode; cathode; at least one separator present between the anode and the cathode; electrolyte; at least one thin film current collector contacting at least one of an anode and a cathode, wherein the current collector comprises a conductive material deposited on a substrate of non-conductive material, wherein the current collector ceases to conduct at the short circuit contact point at an operating voltage of the energy storage system, wherein the voltage is at least 2.0 V; at least one tab attached to said at least one thin film pantograph; and a connecting means configured to attach the tab to the pantograph, wherein the connecting means is in electrical contact with an exposed surface of the tab and the thin film pantograph, and wherein the connecting means is selected from the group consisting of adhesive tape, staples, conductive adhesives, and clips; wherein either the anode or the cathode is located between at least a portion of the thin film current collector and the separator. 10. The energy storage system of claim 9, wherein the clamps clamp the intermediate metal strips or z-folded metal strips. 11. The energy storage system according to claim 9, wherein the connecting means consists of 2-50 connecting means -