Battery Connection and Metallized Film Components of a Power Storage Device with an Internal Fuse

Abstract

A lithium battery is provided that includes an internal fuse assembly and the necessary tabs. The tabs allow electrical conduction between the inside and outside of the device, thereby charging the device. This disclosure provides tabs that, when combined with the internal fuse having the above-described characteristics, achieve a sufficient level of safety. At the same time, the tabs provide sufficient pull-out strength to remain in place during use and fully cover the thin-film metalized current collector for electrical conduction. Furthermore, these tabs effectively weld the necessary connections, achieving incredible levels of amperage and temperature resistance, thereby achieving the basic internal fuse effect, i.e., sufficient electrical conductivity to the external device. These tab lead assembly and welded structures have enabled further technological advancements in the lithium battery field.

Description

Technical Field

[0001] The present disclosure relates to technical improvements in the physical properties of components and lithium batteries. Standard lithium-ion batteries tend to cause certain phenomena due to short circuits, such as the battery itself getting hot or ultimately catching fire. It has been found that structural concerns in battery components are causing such problems. The technical improvements presented here include utilizing thin metallized current collectors (such as aluminum and / or copper), high shrinkage rate materials, materials that become non-conductive when exposed to high temperatures, and combinations thereof. These technical improvements impart performance to the lithium battery that can withstand certain defects (such as dendrites, unexpected electrical surges, etc.), and also prevent unwanted high temperatures caused by short circuits by providing an internal fuse in the lithium battery itself. Batteries and methods of using such batteries that include these technical improvements are included in the present disclosure.

[0002] In particular, the object and importance of the present disclosure is to provide a lithium battery with a necessary tab lead. The tab lead enables electrical conduction between its interior and exterior, and the target device is charged. Since the electrodes are thin and there is a possibility that both sides of the electrode material are not electrically connected to each other, providing a tab lead is important. In the present disclosure, by combining with the internal fuse having the above-mentioned characteristics, a tab that clears a sufficient safety level is disclosed. At the same time, the tab realizes a pulling strength that can stay in place during use, and by completely covering the thin-film metallized current collector, it exerts the effect of electrical conduction. Furthermore, in such tabs, effective welding is performed on the necessary connection parts, and by realizing an amazing level of ampere number and temperature resistance, basic internal fuse effects such as sufficient conductivity to the above-mentioned external device can be realized. These tab lead components and welding structures make it possible to bring about further technological improvements in the field of lithium batteries to the industry.

[0003] Improvements in the internal fuse in the present disclosure have enabled the realization of an ultra-thin current collector structure, and further, it has become possible to fold the current collector multiple times within a single battery. In the case where it cannot be folded, the polymer layer between the two conductive layers electrically insulates both sides of the current collector from each other. However, by being able to fold it in this way, both sides of the current collector can come into contact without requiring excessive internal weight and / or battery volume. The folded current collector increases the charging capacity simultaneously without requiring the above-mentioned excessive weight and volume, and further, for any size of battery, while increasing the charging capacity, it retains the internal fuse characteristics. As a result, a new multi-purpose battery that realizes the targeted high power level and the highest possible safety is realized.

Background Art

[0004] Lithium batteries are widely used around the world as power sources for a wide variety of products. (Various types of ionic) lithium batteries are used as primary power sources from rechargeable power tools to conductive automobiles and general mobile phones (tablets, laptops, etc.) in view of their reliability, the ability to be charged as described above, and their service life. However, although they are widely used power sources in the world, it has been reported that they cause certain problems, including some that are very serious in some cases. In particular, due to certain defects in lithium batteries, regardless of initial defects or aging deterioration, there is a risk of ignition during short circuits, so their safety is being questioned. Basically, internal defects in conductive materials have been found to cause undesirable high temperatures, which in turn lead to ignition within the battery structure. As a result, specific products using lithium batteries, from handy-type computer devices (as a notorious example, the Samsung Galaxy Note7) to entire aircraft (Boeing 787), have had their sales and / or use prohibited until solutions are established for the lithium batteries being used. (In the case of the Samsung Galaxy Note7, bringing it into any aircraft equipment is prohibited in certain regions.) Similar problems related to lithium battery parts have also been found in Tesla's electric vehicles, and the fact that even high-end cars can turn into fireballs due to battery problems has become big news. The widespread recalls and immediate bans on the use of lithium batteries are still a problem today, and urgent solutions are being sought.

[0005] These problems are mainly caused by manufacturing problems during the assembly of individual battery components or individual batteries. More specifically, a lithium battery currently consists mainly of six components: a cathode material, a cathode current collector (e.g., aluminum foil) coated with the cathode material, an anode material, an anode current collector (e.g., copper foil) coated with the anode material, a separator generally made of a plastic material provided between the anode layer and the cathode layer, and an electrolyte. The electrolyte is a conductive organic solvent that, by saturating other materials, constructs a mechanism for ions to conduct between the anode and the cathode. These materials are generally wound together or laminated in a can as shown in the prior art of FIG. 1. In addition, in such battery manufacturing, various configurations such as pouch-type batteries, prismatic batteries, button-type batteries, cylindrical batteries, prismatic wound batteries, and pouch-type wound batteries are conceivable. These batteries can supply power in various applications and repeat charge / discharge cycles thousands of times without causing dangerous accidents as long as they are manufactured accurately and handled carefully. However, as described above, specific situations, especially specific defects, cause internal short circuits between internal conductive materials. This generates heat and causes internal thermal runaway. This is known as the ultimate cause of ignition within a lithium battery. Such situations are caused by internal defects as described above. Internal defects include the residue of metal particles in the battery, burrs on the current collector material, scratches or holes in the separator (including those that originally exist and those formed in subsequent processes), misalignment of the battery layers (where "openings" are formed in unnecessary locations, causing unnecessary conduction), foreign objects entering the battery (e.g., debris on the road that affects moving vehicles), impact and / or vibration on the battery itself (due to accidents, etc.), charging in a narrow space, etc. Generally, such defects are known to cause the formation of fine electrical conduction paths between the anode and the cathode. When such a situation occurs and the battery is charged thereon, discharge occurs from the battery through the conduction path.As a result, ultimately, excessive heat is generated, damaging the battery structure and posing a danger to the base device powered thereby. If there is a combustible organic solvent material such as battery electrolyte (which is essential for the practicality of the battery), the excessive heat can ignite the electrolyte, ultimately creating a very dangerous situation. Once such problems occur at least once, they are difficult to control and may cause significant obstacles to consumers. Such potentially dangerous situations must be surely avoided by providing a battery that supplies electrical energy without damaging the combustible organic electrolyte as described above.

[0006] When overheating occurs inside, the plastic separator shrinks. As a result, the separator may move, come off, or expand the short-circuit area inside the battery. In such a situation, as the exposure of the short-circuit area inside the battery progresses, current continuously flows and further heating progresses. When it reaches a high temperature, it leads to serious damage to the battery such as rupture, ejection, and even ignition and conflagration. Such damage is a particularly serious problem because it may cause ignition and has the risk of leading to a worse situation. For example, there is a risk of explosion for the battery and even the base device, resulting in exposing the user to a significant danger.

[0007] (A variety of) lithium batteries are particularly susceptible to problems caused by short circuits. General batteries tend to show an increase in the discharge rate when exposed to high temperatures. As a result, as described above, sometimes uncontrollable (runaway) ignition and conflagration occur. Due to such risks, certain regulations are imposed on the actual use, storage, and transportation of batteries. Although it is very important to establish appropriate regulations as described above to prevent such runaways caused by short circuits, problems still remain. Especially when parts are produced and supplied by countless suppliers from many different regions around the world, it is difficult to handle and grasp the situation.

[0008] Some people are trying to provide appropriate and / or improved separators as a means of reducing the likelihood of lithium battery ignition. In the case of plastic films with low melting points and / or shrinkage rates, the likelihood of battery ignition is even higher. Thus, as a general concept, it is incorporated to apply a specific coating to the separator material without reducing the electrolyte separation function during actual use. That is, for example, by using ceramic particles as a polypropylene and / or polyethylene film coating, it contributes to the dimensional stability of such films (e.g., raising the melting point). A binder polymer is also included as a component to enhance the cohesiveness of the ceramic particles and the adhesion to the plastic film. In fact, it can be seen that relatively less heat is applied overall to the membrane structure with the ceramic particle coating, and the dominant factor in the separator's issues was the actual separator material itself.

[0009] As a result, a separator material that is much more thermally stable than the porous membranes of polyethylene and polypropylene that typically form the base layer of a ceramic-coated separator has been designed and realized, at least to some extent. Such a separator with a low shrinkage rate and dimensional stability has a shrinkage rate of less than 5% at temperatures of at least 200 degrees Celsius (up to 250 degrees Celsius, 300 degrees Celsius, or higher). This is far superior compared to the high shrinkage rates in bare polymer films (with a shrinkage rate of approximately 40% at 150 degrees Celsius) and ceramic-coated films (exceeding 20% at 180 degrees Celsius) (Figure 2 showing the shrinkage rate measurement comparison demonstrates the prior art). Materials with such a low shrinkage rate change the mechanism of thermal degradation inside the battery in the event of a short circuit. Generally, when such a short circuit occurs in a battery, heat is necessarily generated. In the separator, if shrinkage due to short circuit does not occur, the heat continues to be generated until other materials inside the battery deteriorate. This phenomenon is simulated by the standard nail penetration test in the industry. For example, even a separator with para-aramid fibers that exhibits shrinkage stability up to 550 degrees Celsius shows a tendency to short circuit along with the inherent internal results of the battery under test. After the test, the battery is opened, the excess electrolyte is evaporated, the battery is filled with epoxy, and cut perpendicular to the nail remaining inside the battery. After this process, the battery under test was examined in more detail. First, electron microscope images were taken using backscattered electron imaging (BEI). This enabled mapping of different battery elements and showed the results of the nail penetration operation. The above is explained in Figures 3A and 3B showing the prior art.

[0010] In the prior art's Figure 3A, the copper layer is consistently closer to the nail than the aluminum layer. Also, the separator with high stability is not damaged between the electrodes. The prior art's Figure 3B is an enlarged view of the end of a single aluminum layer, showing that it terminates with a layer of cracked gray material. This was revealed by an investigation using BEI, indicating that the obtained material is aluminum oxide or insulating ceramic. Thus, even if the separator itself has heat resistance, the aluminum current collector oxidizes, resulting in the destruction of the circuit (and after the destruction stops, as a result, insulating aluminum oxide is formed by any short circuit). When the circuit is destroyed, the flow of current stops, heat is no longer generated, the stability of the separator decreases, and the process causing thermal runaway reverses.

[0011] This solution, while possible, is limited to simply replacing only the separator with a high shrinkage rate. Although the solution seems simple and of great value, there are still post-manufacturing processes, and there are also specific components (such as a type of separator coated with ceramic) that are widely and commonly used and difficult to replace from existing battery products. Therefore, even in the case of a separator product coated with ceramic, which is considered to be highly safe in terms of fire prevention, there is a possibility of unwanted battery ignition despite the obvious advantage of using a separator with thermal stability. Thus, in addition to using a separator material with high thermal stability, at least another solution regarding the internal structure mechanism of the battery itself is sought to eliminate or at least reduce the probability of heat generation due to internal short circuits. In such a situation, even if a short circuit occurs inside the battery, in actual internal fuse production, not completing the internal circuit does not necessarily lead to serious high-temperature damage. However, so far, no method that can easily solve such problems has been proposed in the field of lithium battery technology. The present disclosure presents a lithium battery with extremely high safety and reliability as the most desirable solution in any market.

[0012] In particular, a further concern of the present disclosure is to consider that charges are appropriately transferred from the lithium-ion battery to an external source. This is generally achieved by using tabs. Tabs contact and are attached to the current collector, but may be in contact with and attached to both the anode current collector and the cathode current collector in some way. This makes it possible to provide the necessary conductive properties to the external source. Tabs function as connection parts with the components inside the battery in the surface layer, and in order to achieve the conductive purpose, their contact points extend outside the battery casing. Therefore, the tabs must stay in place and not come off the current collector. Furthermore, the tabs must always be in contact with the external source without coming off either internally or externally with respect to the current collector. In the field related to lithium-ion batteries, there is no disclosure regarding such thin-film current collectors, and similarly, there are no attempts to improve and optimize such problems in tab connections. Of course, there are known standard types of tabs that connect to the large current collectors of standard batteries. However, no consideration has been given to maintaining the effects of thin-film current collectors (such as internal fuses) while achieving overall dimensional stability without being affected by battery defects due to structural compromises. Thus, there is no discussion or disclosure in the current field related to lithium-ion batteries and related industries. Therefore, the present disclosure breaks through such a current situation and presents results that have never been seen before and / or can be understood in related industries. Summary of the Invention Problems to be Solved by the Invention

[0013] A distinct advantage of the present disclosure is that, when a short circuit occurs, a mechanism for interrupting the conduction path can be provided by the component parts by stopping or significantly reducing the current that can induce heat generation within the battery. A further advantage is that a protection structure format within a lithium battery can be provided that can achieve advantageous weight and cost at any stage of battery manufacturing, transportation, and use. Thus, further advantages include the fabrication of the internal fuse structure of the battery and its storage until activation. Another advantage is that a lightweight battery can be provided by using a thin current collector that prevents thermal runaway when a short circuit or the like occurs. Yet another advantage is that a combustible organic electrolyte material can be used within the battery while eliminating all ignition factors when a short circuit or the like occurs. A further particular advantage is that a tab component having sufficient conductivity can be provided that simultaneously welds or contacts both the upper and lower surfaces of the internal fuse current collector. Still a further advantage is that a fold can be formed in the thin current collector component disclosed herein. Thereby, power generation can be continuously achieved in a plurality of internal structures having current conductivity, and a robust and desirable battery can be provided as a result without requiring weight or measurement dimensions.

Means for Solving the Problems

[0014] Accordingly, the invention of the present disclosure can include a power storage device, the power storage device including an anode, a cathode, at least one polymer or cloth separator provided between the anode and the cathode, an electrolyte, and at least one current collector in contact with at least one of the anode and the cathode. One of the anode and the cathode is interposed between at least a part of the current collector and the separator. The current collector includes a conductive material covering a polymer material substrate. The current collector stops conducting when it comes into contact with an exposed short-circuit portion at the operating voltage of the power storage device. The voltage is at least 2.0 volts. As an example, the current density at the contact point is 0.1 ampere / mm 2and the tip dimension is 1 mm 2 or less. Of course, in the case of a larger battery, the required threshold value for the current density may be increased, and the current density is at least 0.3 amperes / mm 2 , for example, at least 0.6 amperes / mm 2 , furthermore, at least 1.0 amperes / mm 2 only when the conduction may be stopped. As will be described in detail below, the total thickness of the coated polymer material substrate must be at most 25 microns. The advantageous use method of the current collector component of the power storage device (such as a battery such as a lithium-ion battery, a capacitor, etc.) is also included in the scope of the present disclosure. Furthermore, the thin-film current collector battery may be provided with at least one tab. This tab has a uniform size and is in contact with the thin-film current collector through 2 to 50 weld points existing along the long side of the current collector at regular intervals. At least one tab is disposed on the thin film, whereby at least one tab has an exposed upper surface and a lower surface in contact with the coated surface of the thin-film current collector. Through the weld points, a conductive material is disposed from the exposed upper surface through the tab to the coated surface of the thin-film current collector. Furthermore, the use of the plurality of current collectors described above is also included herein. The current collector is folded to form independent power generation regions connected in series within one battery.

[0015] Another aspect of the present invention is a power storage system, which includes an anode, a cathode, at least one separator provided between the anode and the cathode, and an electrolyte. At least one thin-film current collector may be in contact with at least one of the anode and the cathode. The current collector may include a conductive material covering a non-conductive material substrate. The current collector may stop conducting when it comes into contact with an exposed short-circuit portion at the operating voltage of the power storage device. The voltage may be at least 2.0 volts. At least one tab may be attached to at least one thin-film current collector. The connecting means may be configured to attach the tab to the current collector. The exposed surface of the tab and the thin-film current collector may be in electrical contact with each other by the connecting means. Either the anode or the cathode may be interposed between at least a part of the thin-film current collector and the separator.

[0016] In some or all embodiments of the present invention, the connecting means may be selected from the group consisting of welding, tape, U-shaped clamping, intervening metal strips, Z-shaped folded metal strips, conductive adhesives, and fasteners.

[0017] In some or all embodiments of the present invention, the connecting means may consist of 2 to 50 connecting portions, and the connecting portions may be provided over the entire current collector such that current flows uniformly from the electrode material to the tab.

[0018] In some or all embodiments of the present invention, the current collector may be folded such that the opposite surfaces of the current collector are in contact with each other.

[0019] In some or all embodiments of the present invention, the separator may be a polymer non-woven fabric or ceramic.

[0020] In some or all embodiments of the present invention, the non-conductive material substrate may be a polymer film.

[0021] In some embodiments, or all embodiments, of the present invention, the electrolyte may be a combustible organic electrolyte.

[0022] In some embodiments, or all embodiments, of the present invention, the tab may be a first tab that contacts the upper surface of the current collector and a second tab that contacts the lower surface of the current collector, and the first tab and the second tab may be parallel to each other.

[0023] In some embodiments, or all embodiments, of the present invention, the tab may be folded over the current collector such that the first prong of the tab contacts the upper surface of the current collector and the second prong of the tab contacts the lower surface of the current collector, and the first prong and the second prong may be parallel to each other.

[0024] In some embodiments, or all embodiments, of the present invention, the current collector may have a double-fold structure so as to form two electrical insulation layers.

[0025] In some embodiments, or all embodiments, of the present invention, the current collector may be a plurality of current collectors connected in series, and among the plurality of current collectors, the last current collector may be attached to the tab.

[0026] In some embodiments, or all embodiments, of the present invention, among the plurality of current collectors, a second tab attached to the first current collector may be further provided. The tab and the second tab may be parallel to each other.

Advantages of the Invention

[0027] Furthermore, it may support a higher current density in a very short time or with a probe having an extremely small tip. In such a situation, a stronger current such as 5 amperes, 10 amperes, or 15 amperes may be connected for a very short time (e.g., less than 1 second, or less than 0.1 second, or even less than 0.001 second). In the present disclosure, while allowing a strong current, the transmission time of such a current is shortened so that the total energy transmitted is very small and does not generate enough heat to cause a thermal runaway event in the battery. For example, when a short circuit occurs in a battery having a conventional structure, it is known that a current of 10 amperes occurs at a voltage of 4.2 volts for 30 seconds. As a result, 1,200 joules of energy is transmitted to a locally narrow area within the same battery. As a result, in the battery, the temperature of a portion corresponding to 1 gram is increased by about 300 degrees (Celsius). This temperature is not only high enough to melt the inherent conventional separator material but also causes the entire battery to enter a thermal runaway state (i.e., as described above, the inherent electrolyte material is damaged, and there is a possibility of destroying not only the battery but also the device in which the battery is mounted and the surrounding environment). Therefore, by shortening the duration of the short circuit and suppressing the energy level transmitted by such a short circuit to a low joule value, it is possible to almost prevent thermal runaway (and the potential risks associated with thermal runaway), although it is not complete. For example, by shortening the duration of the short circuit in the current collector to 1 millisecond or less, the amount of energy transmitted can also be reduced to 0.04 joules (this value is the exact opposite of the case where excessive values such as 300 degrees (Celsius) or more and 1,200 joules are shown in the local portion corresponding to 1 gram of the battery described above). By reducing to this level, the heat generation in the local portion corresponding to 1 gram of the battery can be suppressed to about 0.01 degrees (Celsius). Therefore, thermal runaway in the target battery and thus in the entire battery can be prevented.

[0028] Accordingly, a further important advantage of the present disclosure is that it can provide a battery and a current collector that can significantly limit the transmission time of the current level applied to the surface of the target current collector through the tip of the probe. This transmission time is limited to less than 1 second, preferably less than 0.01 second, more preferably less than 1 millisecond, and particularly, in the case of a larger current, most preferably up to 100 microseconds (this enables controllable countermeasures against manufacturing internal defects, dendrites, or external factors that cause internal short circuits in the battery). Of course, such a current is limited by the internal voltage of the battery. The internal voltage may be 5.0V, 4.5V, 4.2V, or lower, and may be a value with a minimum of 2.0V, for example, 4.0V or 3.8V.

[0029] Such a novel current collector component is actually quite different from what is commonly found and used in today's lithium (and other types of) batteries and energy storage devices. Standard current collectors are provided as metallic structures with conductivity, such as aluminum and / or copper panels, and have a thickness that protects the overall structure of the battery or the like. The general current collector structure is designed to achieve the maximum possible electrical conductivity within the constraints of weight and space. However, especially when a short circuit actually occurs, the thick panels commonly seen in today's energy storage devices not only cause arcing but also significantly contribute to thermal runaway in a similar situation, so such a structure does not seem to match the actual situation. For example, dendrites are formed within the separator, causing a short circuit. These deformed parts (formed during manufacturing or long-term use and causing deterioration) unintentionally allow voltage to be transmitted from the anode to the cathode, increasing the current and locally raising the temperature. An example of a defect that is actually considered to cause a short circuit is the burr formed at the end of a generally thick current collector. Burrs are formed by cutting or severing with a worn blade during repeated manufacturing processes (common today) for multiple products. As a result of repeated analysis, it has been found that standard current collector materials simply tend to generate sparks and only increase the temperature. Furthermore, the generated current continues to flow through the device, but here, the generation and movement of the current cannot be controlled, and there is no means to weaken the current and prevent the temperature from rising. These problems directly cause high-temperature thermal runaway. Since there is no internal means to break such a situation, the risk of ignition and, consequently, total loss of the device cannot be avoided. Additionally, the current path (charging direction) of a standard current collector is in a somewhat electrostatic state both before and during a short circuit event. Basically, it shows the expected displacement of charges moving horizontally in a specific direction along the current collector from the cathode to the anode. However, when a short circuit is caused, the movement of these charges cannot be prevented, or at least reduced or delayed, in the current path.In other words, it becomes uncontrollable, and rapid discharge progresses throughout the entire battery. The combination of such rapid discharge and high temperature results in serious situations (such as ignition, rupture, etc.) as described above.

[0030] On the one hand, the current collector of the present disclosure has a general structure and configuration, which is exactly the opposite of conventional lithium batteries. At least by using the current collector of the present disclosure, a very high current density (realized by reducing the thickness of the conductive element) and control over the movement of charges (e.g., movement not in the charging direction) during a short-circuit event are achieved. In other words, by imposing specific structural constraints on the current collector component of the present disclosure, the current density increases, and although it is at a very high temperature due to its resistance level, the heat generation due to short-circuit is suppressed to a certain extent. Therefore, due to this resistance level, the conductive material (e.g., aluminum and / or copper as an example) accepts the charges during a short-circuit, and at the same time, due to the structural formation provided here, the conductive material reacts immediately to the high-temperature and local charges. Regarding other structural considerations for the current collector component, that is, not providing a polymer material with dimensional stability that actually contacts the conductive material layer, the conductive material oxidizes immediately at the charging points it has, for example, changing aluminum or cupric oxide into a non-conductive material. In this way, by instantaneously forming a non-conductive material, the path allowing the movement of charges is interrupted, and the charges during a short-circuit can be released. Therefore, when such a current collector is used, even if a short-circuit occurs inside, the current is immediately interrupted. Furthermore, the heat generation at a high temperature due to the short-circuit is immediately and efficiently utilized to form a barrier against further movement of charges. As a result, there is no longer any current flowing through the main body of the energy storage device (of course, the current generated by the short-circuit), so no undesirable events occur. That is, the short-circuit is completely suppressed, and no runaway current or runaway heat occurs thereafter. Also, perhaps the most important point is that the current collector can maintain its available state without impairing its protective function in its initial state. This is because when the energy storage device (such as a battery) operates as intended, even if a non-conductive material exists locally, the current flow does not decrease. Furthermore, since the region where the non-conductive material is formed in the current collector remains within a relatively small area, sufficient surface area remains for continuous use, and no repairs, replacements, or other restoration actions are necessary.Although it does not always occur, such a situation cannot be surely realized without certain preventive measures or corrections. That is, without certain preventive measures or corrections, in fact, the risk of being exposed to high temperatures and the possibility of destructive events as described above will become considerably higher than normal. Therefore, since it becomes unstable under the situation where a short circuit occurs, the entire current collector is made into a two-dimensional electrical fuse. Thereby, it is possible to prevent a high current caused by a short circuit and having potential risks. This current is strong enough to destroy the function of the current collector that conducts electricity to the short-circuited portion, and the effect is instantaneously utilized.

[0031] Such advantages are realized by the novel current collector provided here. Even with a number of alternative means, the current collector can produce similar advantages and results. No matter what alternative configuration it has, the current collector described here functions as an internal fuse in the target power storage device (for example, a lithium battery, a capacitor, etc.). In each example (each alternative), a current collector provided with a polymer layer is provided. One or both sides of the layer are metallized, and at least one metallized side contacts the anode or cathode of the target power storage device. As one alternative configuration, the total thickness of the metallized (coated) polymer base material of the current collector is made less than 20 microns, preferably less than 15 microns if possible, and more preferably less than 10 microns if possible, and the resistance value is less than 1 ohm / square, preferably less than 0.1 ohm / square if possible, and more preferably less than 50 ohm / square if possible. Although general current collectors also have such characteristics, they are much heavier than those made of reinforced polymer base materials, and furthermore, the advantages in terms of safety, which are also the characteristics of the modified examples disclosed here, are neglected. For example, the weight of a copper foil having a thickness of 10 microns is 90 g / m 2 However, the weight of the copperized foil is about 50 g / m 2 or about 30 g / m 2 or about 20 g / m 2Even if it is less, in any case, the electrical performance required for the battery to function is fully exerted. In such an alternative structure, by making the thickness of the component very thin, when a short circuit occurs, the metal coating reacts at all resistance levels. As a result, due to the excessive high temperature caused by the current spike at the time of short circuit occurrence, metal oxide is locally formed, and any current movement from there is immediately blocked.

[0032] As another alternative configuration in such a novel current collector, a temperature-dependent metal (or metallized) material is used. This material contracts upon heating during a short circuit or easily deteriorates, causing a specific material region to change into a non-conductive material (for example, aluminum oxide changed from an aluminum current collector as shown in an example presented from another perspective). In this way, a current collector that is the exact opposite of the aluminum and copper current collectors, which are current collectors used today and have very high stability against heat even at high temperatures, is obtained. As a result, an alloy of a metal with a low melting point originally deteriorates under a low current density during a short circuit. This improves the safety advantages of the lithium-powered devices of the present disclosure. Another alternative configuration is to fabricate a current collector by coating a layer of a conductive material. For example, a coating is applied with copper or aluminum on a fiber or film having a relatively high shrinkage rate at a relatively low temperature. In such examples, a thermoplastic film with a melting point below 250 degrees Celsius or 200 degrees Celsius is used. The thermoplastic film includes, without limitation, polyethylene terephthalate, nylon, polyethylene, or polypropylene. To obtain similar results, a current collector may be fabricated in another way by coating a layer of a conductive material. For example, a coating is applied with the aforementioned copper or aluminum on a fiber or film. Here, the fiber or film swells or dissolves in the electrolyte when heated at a relatively high temperature that is higher than the operating temperature of the battery and lower than the temperature that can cause thermal runaway. Examples of such polymers that swell in a lithium-ion electrolyte include polyvinylidene fluoride and polyacrylonitrile, but other polymers known in the art may also be used. As another method for realizing an alternative structure in the internal electrical fuse formation process, the substrate may be coated with a metal, such as aluminum. Aluminum oxidizes when heated and generally has a much thinner total thickness compared to the metals commonly used in lithium batteries. For example, today, for a very thin aluminum current collector, its thickness is about 20 microns.If the total thickness of the coating is less than 5 microns, the circuit is quickly interrupted, and if it is less than 2 microns or less than 1 micron, the circuit is interrupted even faster. As yet another method of realizing the interruption of the conduction path, providing a current collector with a limited conductivity can be mentioned. Such current collectors deteriorate due to the high current density around the short circuit, similar to commercially available fuses available today. It is possible to provide a current collector having an electrical resistance value higher than 5 milliohms / square, or higher than 10 milliohms / square, preferably higher than 20 milliohms / square if possible, and even more preferably higher than 50 milliohms / square if possible. These values may be measured on one or both sides of the coating material. For batteries designed for high power, current collectors with different electrical resistance values may be selectively provided. Such batteries have a relatively lower electrical resistance value and / or a relatively higher electrical resistance value compared to batteries designed for low power and high energy. As yet another method of realizing the interruption of the conduction path, providing a current collector that oxidizes at a temperature even lower than aluminum and changes to a non-conductive material can be mentioned. Thereby, before the separator deteriorates, the function of the current collector stops in the region where the short circuit has occurred. Certain aluminum alloys have a faster oxidation rate compared to aluminum itself, and such alloys cause the conduction path to deteriorate at a lower temperature. As a possible alternative configuration, any type of metal that conducts electricity can be used for the thin layer, including, without limitation, gold, silver, vanadium, rubidium, iridium, indium, platinum, etc. (Basically, because the layer thickness is extremely thin, the cost of using the metal can be significantly reduced without sacrificing conductivity and while protecting against the risk of thermal runaway in the event of a short circuit or the like). Also, layers made of different metals may be employed, or a dispersed arrangement of the metal in a separate layer member may be used. Also, of course, in the coated current collector substrate, different types of metals may be used for one surface compared to the other surface, and each may have layers of different thicknesses.

[0033] As one way to improve the electrical characteristics of a battery, it is possible to reliably apply a conductive coating to both sides of a current collector. That is, electricity is made to pass through the coating from one side to the other. This cannot be achieved, for example, with an uncoated polymer film. However, as a non-limiting example, such double-sided conductive throughput can be realized by a nonwoven fabric containing conductive fibers at a certain ratio, a nonwoven fabric having a conductive material, a nonwoven fabric made of a conductive material (e.g., carbon fiber or metal fiber), or a nonwoven fabric containing fibers coated with the above-mentioned conductive material (e.g., fibers having a metal coating on the surface). As another example of a novel thin current collector material that conducts electricity from the top surface to the bottom surface, there is a film formed to have conductivity. This can be achieved by using a conductive material itself (e.g., a conductive polymer such as polyacetylene, polyaniline, polyvinylpyrrolidinone) or by adding a conductive material (e.g., graphite, graphene, metal particles, or metal fibers) during or after the production of the film. Further, as a double-sided type of thin current collector material, there is a porous one having small holes and having both sides coated with a metal (aluminum or copper) by a metallization process. The conductivity from one side to the other does not need to be at the same level as that of the conductive coating.

[0034] Therefore, by these alternative configurations, it is possible to obtain a similar current collector having the following physical characteristics. a. The total thickness of the coated polymer substrate is less than 20 microns and the electrical resistance value is less than 1 ohm / square. b. The current collector includes a conductive material that coats a substrate made of a polymer material, and the polymer material has a shrinkage rate of at least 5% at 225 degrees (Celsius). c. The metallized polymer material of the current collector swells in the electrolyte of the battery, and the swelling progresses as the polymer material is heated. d. When applied to the polymer substrate, the total thickness of the conductive material of the current collector is less than 5 microns. e. The conductivity of the current collector is from 10 milliohms per square to 1 ohm per square. f. The metallized polymer substrate in the current collector has a porosity of at most 60%. Using such alternative configurations together with a separator having a thermal shrinkage rate of less than 5% after 1 hour at 225 degrees Celsius is also included within the scope of the present disclosure. The overall use (usage method) of this type of electrical energy storage device (such as a battery, capacitor, etc.) is also included within the scope of the present disclosure.

[0035] The first advantage of the present invention is in ensuring the safety of the battery. However, as already mentioned to some extent, other advantages are also provided. For example, by suppressing the metal weight used in the current collector component, the weight of the entire electrical energy storage device is suppressed. Also, as the current collector used in such a battery, using a thin polymer layer coated with metal, particularly one with low dimensional stability characteristics, is completely different from the prior art and is unprecedented. In the concept of the same industry, to obtain a desirable protective effect (especially the protective effect from the risk of short - circuit events), it was firmly believed that the weight of actual metal and / or insulator components had to be increased. However, in addition to such a paradigm being inaccurate, it has been found that an effective solution to problems related to short - circuits in lithium batteries, etc., is not to increase the amount of metal, but rather to decrease the amount of metal and combine it with a base layer with low thermal stability. Further, unexpectedly, by providing a thin metal layer together with such an unstable base layer, not only can the discharge event during short - circuit be effectively interrupted and addressed, but in addition to high safety and reliability, the weight and volume of the entire component can be significantly reduced. Therefore, the electrical energy storage product (such as a battery) is lightened and miniaturized, thereby improving its characteristics, and the advantages obtained thereby are more in line with the industry's needs than originally anticipated.

[0036] Also, 2.7 grams / cm 3For aluminum with a density of and a thickness of 20 microns, its weight is 54 grams / m 2 However, when a 10-micron-thick polypropylene film (density: 0.9 grams / cm 3 ) is coated with 1-micron-thick aluminum, its weight is 11.7 grams / m 2 By reducing the weight of the current collector, the entire target power storage device (e.g., battery) is also made lighter, thus improving mobility, fuel efficiency, and electric range, and generally enhancing the value of mobile electric devices.

[0037] Furthermore, because the film has high strength, the film mentioned in the example can be made thinner. For example, the overall thickness can be reduced from 20 microns to 11 microns. This enables the miniaturization of the battery and efficiently increases the energy density. In this way, a current collector 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 fabricated and used to achieve the above-mentioned objectives and functions.

[0038] The bulk electrical resistivity of aluminum is 2.7×10 -8 ohm / m, and the bulk electrical resistivity of copper is 1.68×10 -8Since it is in ohms / m, a thin coating can be formed to be less than 1 ohm / square, less than 0.5 ohm / square, less than 0.1 ohm / square, or, if possible, most preferably less than 0.05 ohm / square. The thickness of the conductive coating can be less than 5 microns, preferably less than 3 microns, more preferably less than 2 microns, and, if possible, most preferably less than 1 micron. Since commercially available standard ones often contain metals with a thickness of 10 microns or more, it is very innovative that appropriate performance can be achieved with such a thin thickness. Certainly, most of the metals used in standard power storage devices are used to obtain the mechanical properties necessary for performing automatic processing at high speed. One of the advantages in the present invention is that a polymer material with a lower density can be used. In this way, it is possible to realize the mechanical property that the thickness of the metal can be suppressed to the extent that the safety of the battery is improved. This is because the current collector cannot support a dangerous high current density that is caused by an internal electrical short and can further cause thermal runaway, smoke generation, and ignition.

[0039] Furthermore, the conductive layer may be composed of a plurality of layers. For example, an aluminum layer may be used as a base layer and coated with a thin layer made of copper. In this way, bulk conductivity can be realized by aluminum, which is lightweight, inexpensive, and can be easily vapor-deposited by vapor deposition technology. Also, copper can realize further conductivity and passivation against the anode without significantly increasing the cost and weight. This example is merely an example, and those skilled in the art can provide a number of conductors having a multilayer structure, any of which can be regarded as an excellent example in the present invention.

[0040] The thin metal coating generally has a higher electrical resistance value than a normal current collector made of aluminum or copper, which brings about a prominent feature of the present invention. Such a novel current collector is configured to exceed 10 milliohms / square, preferably exceed 20 milliohms / square, more preferably exceed 50 milliohms / square, and, if possible, most preferably exceed 100 milliohms / square.

[0041] Furthermore, for the battery composed of the heat-sensitive current collector described above, higher safety can be achieved when the separator has high thermal stability. High stability means showing a low shrinkage rate at high temperatures. For example, the shrinkage rate is less than 5% after 1 hour at a temperature of 200 degrees Celsius, preferably 1 hour at a temperature of 250 degrees Celsius, and more preferably 1 hour at a temperature of 300 degrees Celsius if possible. Existing separators are composed of polyethylene with a melting point of 138 degrees Celsius and polypropylene with a melting point of 164 degrees Celsius. Such materials have a shrinkage rate of 50% at 150 degrees Celsius as shown in Figure 2, but this value is too high for use with the novel thin current collector disclosed herein. As a solution to this problem, it has been clarified that it is necessary to use a specific separator that shrinks less than 50%, less than 30%, and less than 10% at 150 degrees Celsius as measured by NASA TM-2010-216099 Section 3.5. Even separators with ceramic coatings show significant shrinkage at relatively low temperatures, either completely breaking or shrinking by 20% or more at 180 degrees Celsius. Therefore, it is desirable to use a separator that does not break during the test and does not shrink by more than 20%, more preferably more than 10% at 180 degrees Celsius (at least) when measured by the same test standard. In the most preferred embodiment, a separator with a shrinkage rate of less than 10% when exposed to 200 degrees Celsius, or 250 degrees Celsius, or even 300 degrees Celsius is utilized.

[0042] For any of these metallized substrates, it is desirable to have a thickness such that the energy density of the battery can be easily increased. Such a thickness can be achieved by reducing the overall thickness by any method such as calendaring, compression, hot pressing, or even removing material from the surface. Such thickness-reducing processes may be carried out before or after metallization. Therefore, the overall thickness of the metallized substrate is desirably less than 25 microns, preferably less than 20 microns, more preferably less than 16 microns, and most preferably less than 14 microns if possible. Commercially available polyester films have achieved a maximum thickness of 3 microns and even thinner, 1.2 microns. These types of polyester films function as suitable substrates and can make the thickness of the entire current collector less than 10 microns, preferably less than 6 microns, and more preferably less than 4 microns. Such ultra-thin current collectors (having appropriate conductivity as described above and throughout) enable much higher energy density and improved safety performance. These are results that have not been explored before. Such ultra-thin current collectors (having appropriate conductivity as described above and throughout the specification) can achieve a very high energy density while ensuring higher safety performance. Such results have not been revealed so far.

[0043] Also, it is desirable to reduce the weight of the metallized substrate. This can be achieved by using low-density polymer materials such as polyolefins, and by way of example only, other low-density polymers such as polyethylene, polypropylene, and polymethylpentene. It can also be achieved by providing a porous structure in the substrate or by using a lightweight substrate. Therefore, the polymer density in the substrate is less than 1.4 g / cm 3 , preferably less than 1.2 g / cm 3 , and more preferably less than 1.0 g / cm 3 if possible. Also, the areal density of the substrate is less than 20 g / m 2 , preferably less than 16 g / m 2Less than, and if possible, most preferably, 14 grams / m 2 It may also be less. Further, the areal density of the polymer substrate coated with metal is 40 grams / m 2 Less than, preferably, 30 grams / m 2 Less than, more preferably, 25 grams / m 2 Less than, and if possible, most preferably, 20 grams / m 2 It may also be less.

[0044] Weight reduction can also be achieved by a porous polymer substrate. However, for these materials, if the porosity is too high, the strength decreases and the thickness increases, so the objective cannot be achieved. Therefore, the porosity of the base material is less than about 60%, preferably less than 50%, and more preferably less than 40% if possible. Since a solid material can be used for this type of current collector coated with metal, there is no lower limit for the porosity.

[0045] To obtain a battery by processing the material at high speed, a certain degree of high strength is required. This is achieved by using an extended polymer that is from fibers or is stretched from a film uniaxially or biaxially.

[0046] As will be described with reference to the accompanying drawings and their description, power storage devices such as batteries, capacitors, and supercapacitors are manufactured and provided in accordance with the present disclosure. Here, after a short circuit occurs, at least one current collector with no obvious current movement contacts two separate current collectors that contact the cathode, anode, or both, and the separator and electrolyte are both provided and sealed within a standard (and appropriate) power storage device container. The cathode, anode, container, electrolyte, and, in some cases, the separator, and the components are almost all standard. However, the current collector described here is, as disclosed, novel and not yet clearly disclosed in the art, and is completely different from the components of an actual power storage device. This will also be described in more detail below.

[0047] As described above, even if it is not possible to completely prevent thermal runaway in a battery (specifically, here a lithium-ion rechargeable type, but of course other types of batteries may also be used), in order to reduce the risk, any internal short circuit basically requires specific means to be limited to a short occurrence time. This means suppressing the residence time of the short circuit within the target current collector or on the current collector, and ultimately keeping the resulting energy level at a minimum Joule level (i.e., less than 10, preferably less than 1, most preferably less than 0.01). As mentioned above, in such a situation, in the electrical path from the anode to the cathode through the separator where a thin conductive current collector is arranged and a combustible organic electrolyte exists, it has been observed that a lightweight and thin current collector brings about desirable results. In particular, it has been a desirable result in that there is no significant temperature rise on the current collector surface that induces undesirable charge dissipation or ignition of the electrolyte components. Surprisingly, and without being limited to any specific scientific explanation or proof, due to the conductive properties of the thin current collector material, it is considered that the short-circuit charge immediately reaches only the thin conductive current collector and causes a short-duration and high-energy event where a reaction occurs between the metal on the current collector surface and the charge itself. As a result, metal oxide is formed at specific locations on the current collector surface. The metal oxide exhibits insulating properties and further electrical activity and the applied current dissipates instantaneously. Although there is still a risk of deformation of the current collector itself, the presence of the above-mentioned metal oxide protects its position from any charge movement. Therefore, the remaining current collector can be undamaged and provide the same function as before the short circuit occurred, and even if there is a possibility of a short circuit or a similar phenomenon occurring, it can exhibit the same protection function. Consider the case where thermal runaway occurs in a battery product of the prior art. For example, in such products, the anode, cathode, current collector, and separator form an electrical path, and as a result, in response to the short circuit, heat is generated and the battery catches fire due to the spark. Furthermore, since a combustible electrolyte for transporting ions was also provided, the high temperature generated by such unexpected charges was made even more dangerous.Essentially, the heat generated in the prior art current collector caused an initial electrochemical reaction within the electrolyte material, ultimately leading to an uncontrollable ignition of the electrolyte material itself. Therefore, the inventive current collector disclosed herein particularly demonstrates its value when used in a battery equipped with such a flammable electrolyte. As an example, generally, such electrolytes include organic solvents such as carbonates like propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate. These electrolytes are usually used as a mixture of the above materials and may also be used together with other solvent materials such as various additives. These electrolytes also have a lithium salt component such as lithium hexafluorophosphate or LiPF6. Although such electrolytes are favorable in the field related to batteries, as described above, they are potential factors that can cause dangerous situations. Here too, the inventive current collector can significantly and surprisingly improve such problems when used together with other battery components.

[0048] One way to demonstrate the usefulness of the current collector is through the following test. For a current source having both voltage limitation and current limitation, the voltage limitation can be set to be the same as the operating voltage of the energy storage device. Subsequently, the current can be adjusted to test the current collector in two configurations. In the first configuration, a short piece made of a current collector of a known width is brought into contact via two metal connectors that contact the entire width of the sample. By increasing the current limitation of the current source, it can be investigated whether there is a limit to the ability of the material to carry current. This can be measured as the total current divided by the width, and the result is shown in units of A / cm as the horizontal current density. In the second configuration, the ground of the current source is brought into contact with one of the metal contacts of the entire width, and furthermore, the tip of a probe of about 0.25 mm 2 is brought into contact with a position along the current collector piece. If the current is too high, the local area will burn out and the current will stop flowing. If the current is not too high for the current collector, the full current up to the limit of the current source will flow. The result is in A / mm 2It is the limitation of the current indicated in units of , and here it is called the vertical current density. In this way, the current collectors capable of reaching high currents in both configurations are the same as in the prior art and can hold the horizontal current when in contact over the entire width, but in the case of point contact, a current collector that does not hold the same vertical current corresponds to an example of the present invention described herein.

[0049] For example, a current collector that can even hold a horizontal current density of 0.1 A / cm, 0.5 A / cm, 1 A / cm, 2 A / cm, or 5 A / cm may be desirable. Furthermore, in a current collector capable of holding the above horizontal current density, 0.1 A / mm 2 , 0.5 A / mm 2 , 1 A / mm 2 , 2 A / mm 2 , or 5 A / mm 2 It is desirable not to even hold the vertical current density of.

[0050] As described above, generally, tabs are also provided in a lithium-ion battery, and this tab is joined to internal components, particularly the current collector, by welding. Thereby, at the same time, the tab lead for transporting charges is connected to an external source. Under this situation, in the case of an extremely thin current collector, the tab lead effectively contacts the internal foil current collector and stays sufficiently in place, so it is very excellent in that the connection to the external source can be maintained. Furthermore, in addition to being able to provide internal fuse characteristics to prevent runaway current when problems that can be expected (such as dendrite formation) are caused, due to the unexpectedly excellent effectiveness of the thin-film-like current collector described above, the operation required of the battery itself becomes possible. Therefore, in dealing with the same potential problems regarding charge runaway itself, no displacement or ineffectiveness is allowed for the tab. In other words, even if a problem occurs in the tab, it must not affect the effectiveness of the internal fuse. Surprisingly, such required characteristics have been judged to be acceptable in tab components.

[0051] Therefore, at such a level, it has been found that the tab can be effectively and firmly welded by the current collector of the thin film, and can have conductivity on both sides of the film. In fact, the tab itself is thicker than the individual current collectors, and when they are in contact with each other, welding may be performed at a depth where the tab material partially overlaps with respect to the shape and depth of the welding itself. However, as an unexpected result, in fact, the welding may penetrate a thin and elongated tab or the like, and thereby electricity can pass from the welding material to the tab. As a result, a restricted but effective conductive path is formed. It is possible to provide means not only to ensure the conductivity to the tab (and further to an external source outside the battery casing) required at the welding location, but also to limit the actual amperage and the heat generated by the flow of electricity at each welding location. Thus, even if a short circuit (such as dendrite formation) occurs, the conductive runaway on the current collector of the metallized film can be controlled as described above. This is because the charge stays on the surface of the actual current collector and no path is provided for the runaway charge to move. For example, welding may be applied at up to five locations, evenly spaced from each other, in the length direction of the tab component along the current collector. Thereby, effective conductivity is established from the foil current collector through the battery casing towards the tab and ultimately towards the external source. Even if the amperage presented by each is restricted, there is a level of redundancy, and in some situations, it will surely increase, but by limiting the number of welds, the number of sites where charge can run away can also be restricted. However, in the case of a high-power or high-current battery, the number of welding locations per tab may be increased, thereby maintaining the high current level required for the battery to be useful in its application. In this case, a large number of welding locations, for example, 10, 20, or 50 welding locations per tab can be provided. In rare cases, for a battery with a very high output or very strong current, more than 50 welding locations may be provided. The welding locations provide a base strength and further prevent the movement of the tab during use. Stability and rigidity are required for the proper operation of the entire battery to be as intended.In this regard, restricting the welding locations can ensure a certain degree of reliability. Additionally, by adding a pull tape thereon and providing it on the current collector film, it helps to protect against problems caused by such potentials.

[0052] In fact, the thin-film current collector is unexpectedly suitable for preventing runaway charges during a short circuit. However, in order to establish effective conductivity with the outside of the battery, it is necessary to fully contact the tab lead with the current collector. For this purpose, it is necessary to realize a structural situation where such a thin current collector film can be used together with standard tab components. To effectively conduct the battery operation, appropriate welding is required so that the placement and contact are effective for current flow. However, it is difficult to appropriately set the dimensions for both the current collector film and the tab while showing an appropriate low potential during runaway charges and performing appropriate welding as described above. This is particularly difficult in the case of monolithic and thick specific current collector components that are accepted in the current technology. Due to the unexpected effectiveness, particularly the tab contact and pull-out strength characteristics determined as described above, it is possible to reduce the weight or increase the internal capacitance that other components can occupy without sacrificing the battery power generation performance, and at the same time, realize a complete lithium-ion battery that is thoroughly protected from runaway charges during a short circuit.

[0053] Such thin films of lithium-ion batteries require certain specific processing steps to achieve their unique performance. However, various processing steps known in the art can be adopted. Generally, a method for manufacturing a lithium-ion battery with a film having progressiveness is a. preparing an electrode having at least one metallized substrate coated with an ion storage material; b. preparing a counter electrode; c. facing the electrode and the counter electrode towards each other and further stacking a separator component interposed between the electrode and the counter electrode; d. preparing a packaging material having an electrical contact component having a part existing inside the packaging material and a part existing outside the packaging material; e. electrically connecting the electrical contact part to the metallized substrate; f. introducing at least one liquid electrolyte containing ions into the packaging material; g. sealing the packaging material. It includes.

[0054] The metallized substrate may be any substrate described in the present disclosure.

[0055] For example, the ion storage material may be a cathode material or an anode material for a lithium ion battery known in the art. Examples of the cathode material include lithium cobaltate (LiCoC2), lithium iron phosphate (LiFePO4), lithium manganese oxide (LiMn2O4), lithium manganese nickel cobalt oxide (LiNi x Mn y Co z O2), lithium nickel cobalt aluminum oxide (LiNi x Co y Al z O2), or a mixture of the above, or other materials known in the art. Examples of the anode material include graphite, lithium titanate (Li4Ti5O 12 ), hard carbon, tin, silicon, or a mixture thereof, or other materials known in the art. Furthermore, the ion storage material may be a material used in other energy storage devices such as supercapacitors. In such supercapacitors, examples of the ion storage material include activated carbon, activated carbon fiber, carbide-derived carbon, carbon aerogel, graphite, graphene, and carbon nanotube.

[0056] The coating process may be any coating process generally known in the art. Usually, in the coating process of a lithium-ion battery, a roll knife coater and a slot die are used, but other methods including an electroless plating method may also be utilized. In the coating process, the ion storage material is generally mixed with a binder such as polyvinylidene fluoride or carboxymethyl cellulose, or other materials such as other film-forming polymers. Other additives to the mixture include carbon black and other conductive additives.

[0057] The counter electrode includes other electrode materials having an electrochemical potential different from that of the ion storage material. Generally, when the ion storage material is a lithium-ion anode material, the counter electrode consists of a lithium-ion cathode material. When the ion storage material is a lithium-ion cathode material, the counter electrode may be formed from a lithium-ion anode material. When the ion storage material is a supercapacitor material, the counter electrode may be formed from a supercapacitor material, or in some cases, a lithium-ion anode material or a lithium-ion cathode material. In any case, the counter electrode includes an ion storage material coated on a current collector material, which can be a metal foil or a metallized film as in the present invention.

[0058] In the lamination process, the inventive electrode is laminated together with a counter electrode having electrode materials facing each other and a porous separator interposed therebetween. As is generally known in the art, the electrodes may be coated on both sides, and in an electrode stack formed of the inventive electrode and the counter electrode, a separator is provided between each layer. Alternatively, as is known in the art, electrode material pieces may be stacked and wound into a cylindrical shape as described above.

[0059] Examples of packaging materials include rigid ones such as cans for cylindrical batteries, hard cases on a plane, and polymer pouches. In any case, two means of making electrical contact are required through a case that holds different voltages and can conduct current. In some cases, a first part of the case itself may function as the first means, while a second part of the case, which is electrically insulated from the first part, may function as the second means. In other cases, while making the case itself non-conductive, two metal conductors (often referred to as tabs) may be protruded from the case.

[0060] To make electrical contact with the metallized substrate, methods of connecting these means include commonly used methods such as welding, taping, clamping, stapling, riveting, and other mechanical means. Since the metal of the metallized substrate may be extremely thin, generally, surface contact is required to achieve a strong current flow. Thereby, the surface area between the means of making electrical contact through the case and the metallized substrate can be greatly expanded. To allow sufficient current to flow, this surface area needs to be larger than 1 square millimeter (10 - 12 square meters), and further, it needs to be larger than 3 square millimeters, 5 square millimeters, and more preferably, exceed 10 square millimeters.

[0061] The liquid electrolyte is generally a combination / mixture of a polar solvent and a lithium salt. Commonly used polar solvents include propylene carbonate, ethylene carbonate, dimethyl carbonate, and diethyl carbonate as described above, but other polar solvents such as ionic solutions or, in some cases, water may also be used. Lithium salts commonly used in this industrial field are LiPF6, LiPF4, LiBF4, LiClO4, etc., but are not limited thereto. The electrolyte may contain additives known in the art. In many cases, the electrolyte is flammable, but here, the safety characteristics of the current collector of the progressive metallized substrate are exerted in preventing dangerous thermal runaway events that can cause fires and damage to both the battery and outside the battery.

Brief Description of the Drawings

[0062]

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[0063] The following description and examples merely illustrate potential embodiments of the present disclosure, and the scope of the disclosure and the area it covers with respect to the following claims will be fully understood by those skilled in the art.

[0064] As described above, the present disclosure represents a significant departure from previous understandings and approaches in the lithium battery (and other energy storage device) industry, being the exact opposite thereof. The novel devices described herein are, of course, unexpected in this field, yet they provide a number of beneficial results and characteristics that have not been explored heretofore. First, it is considered important to clarify the clear differences between conventional devices and those widely disclosed herein, based on a comparison.

[0065] Examples related to short-circuit events, etc. Comparative Example 1 A cathode for a lithium iron phosphate battery was obtained from GBSystems (China). The aluminum tab was removed and used as an example of a commercially available current collector. Then, its thickness, areal density, and electrical resistance value were measured. The results are listed in Table 1 below. Next, a high-temperature soldering iron was applied to the aluminum foil for 5 seconds. At this time, measurements were taken using an infrared thermometer so that the temperature would be between 500°F and 525°F. Even when the soldering iron was applied to the current collector, no effect was observed. Then, the thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175°C for 30 minutes, and then the shrinkage rate was measured. As shown in FIG. 6, a photograph was left. FIG. 5 shows a conventional current collector within the battery for comparison.

[0066] Comparative Example 2 The anode for the lithium iron phosphate battery was obtained from GBSystems (China). The copper tab was removed, and a commercially available current collector was used as an example. Then, its thickness, areal density, and electrical resistance value were measured. The results are shown in Table 1 below. Next, a high-temperature soldering iron was applied to the copper foil in the same manner as in Comparative Example 1. Even when the soldering iron was applied to the current collector, no influence was observed. Then, the thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees Celsius for 30 minutes, and then the shrinkage rate was measured. As shown in Figure 6, a photograph was left. As in Comparative Example 1, the internal structure of the battery is shown in Figure 5. Since it has a monolithic metal structure rather than the thin type as disclosed, the thickness of the current collector is clear.

Example

[0067] The polypropylene lithium battery separator material was obtained from MTICorporation. The material was manufactured by Celgard under the product number 2500. Its thickness, areal density, and electrical resistance value were measured, and the results are shown in Table 1 below. In the same manner as in Comparative Example 1, a high-temperature soldering iron was applied to the separator. When the thermometer was applied to the current collector, small holes were formed. The diameter was measured and described in Table 1. The thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees Celsius for 30 minutes, and then the shrinkage rate was measured. As shown in Figure 7, a photograph was left.

Example

[0068] The ceramic-coated polyethylene lithium battery separator material was obtained from MTICorporation. Its thickness, areal density, and electrical resistance value were measured, and the results are shown in Table 1 below. In the same manner as in Example 1, a high-temperature soldering iron was applied to the separator. When the soldering iron was applied to the current collector, small holes were formed. The diameter was measured and described in Table 1. The thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees Celsius for 30 minutes, and then the shrinkage rate was measured. As shown in Figure 7A, a photograph was left.

Example

[0069] The ceramic-coated polypropylene lithium battery separator material was obtained from MTICorporation. The thickness, areal density, and electrical resistance value were measured, and the results are shown in Table 1 below. Similar to Example 1, a soldering iron was applied to the separator. When the soldering iron was applied to the current collector, small holes were formed. The diameter was measured and described in Table 1. The thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees Celsius for 30 minutes, and then the shrinkage rate was measured. As shown in Figure 7B, a photograph was left.

Example

[0070] The aluminized biaxially oriented polyester film was obtained from AllFoilsInc. This was originally designed for helium balloons for events. By being coated with aluminum, it can hold helium for a long time, enabling the event balloon to float for a long time. The thickness, areal density, and electrical resistance value were measured, and the results are shown in Table 1 below. Then, similar to Example 1, a high-temperature soldering iron was applied to the film. When the soldering iron was applied to the current collector, small holes were formed. The diameter was measured and described in Table 1. The thickness, areal density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees Celsius for 30 minutes, and then the shrinkage rate was measured. As shown in Figure 8, a photograph was left. Compared with the commercially available aluminum current collector shown in Comparative Example 1, this material is 65% thinner, 85% lighter, and further keeps away heat. Thereby, it exerts an effect of blocking internal short circuits for lithium-ion batteries having a risk of internal short circuits.

Example

[0071] A commercially available lithium-ion battery separator named DreamweaverSilver25 was obtained. This was manufactured by mixing cellulose, nanofibers of polyacrylonitrile, and microfibers of polyester in the manner of a papermaking process and suppressing the thickness by calendaring. Then, in the same manner as in Example 1, a high-temperature soldering iron was applied to the separator. Even when a thermometer was applied to the current collector, no holes were formed. The thickness, surface density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees (Celsius) for 30 minutes, and then the shrinkage rate was measured. Compared with the prior arts of Comparative Examples 3 to 5, these materials have the advantage of not melting or shrinking even when heated. Therefore, in a lithium-ion battery that has the possibility of internal short circuit, a situation where heat is not dissipated and the internal short circuit is made larger may be seen from FIG. 8A.

Example

[0072] DreamweaverGold20, which is a prototype of a commercially available lithium-ion battery separator, was obtained. This was manufactured by mixing cellulose, para-aramid nanofibers, and microfibers of polyester in the manner of a papermaking process and suppressing the thickness by calendaring. In the same manner as in Example 1, a high-temperature soldering iron was applied to the separator. As shown in FIG. 8B, even when a thermometer was applied to the current collector, no holes were formed. The thickness, surface density, and electrical resistance value were measured. The material was placed in an oven at 175 degrees (Celsius) for 30 minutes, and then the shrinkage rate was measured. The advantages of the separator when compared with the prior art separator are the same as those in Example 2.

[0073]

Table 1

[0074] Comparative Examples 1 and 2 are existing current collector materials, showing very low electrical resistance values and high areal densities. Even when applied to the tip of high-temperature solder, they do not react at all and do not show shrinkage even at a temperature of 175 degrees Celsius.

[0075] Examples 1 to 3 are materials having infinite electrical resistance values and low areal densities, which melt when applied at 175 degrees Celsius or to the tip of high-temperature solder. These are excellent base materials for metallization according to the present invention.

[0076] Example 4 is an example of an aluminized polymer film having medium electrical resistance value and low areal density, which shrinks at 175 degrees Celsius or when applied to the tip of high-temperature solder. This is an example of a potential cathode current collector composite film according to the present invention. In practice, as shown in further examples, it may be desirable to apply a higher level of metal coating to make a higher-output battery.

[0077] Examples 5 and 6 are materials having infinite electrical resistance values and low areal densities, and having a very low shrinkage rate at 175 degrees Celsius or even when applied to the tip of high-temperature solder. These are examples of polymer base materials in the present invention when the thickness of the metallized film is sufficiently thin such that the metallized film deteriorates under strong current conditions due to short circuits. Furthermore, cellulose nanofibers and polyester microfibers undergo oxidation, shrinkage, and ablation at a temperature far lower than the melting point of currently actually used metal current collectors.

[0078] Furthermore, Example 5 is made of fibers, polyacrylonitrile, and swells when exposed to a conventional lithium-ion carbonate electrolyte. This is also an example of a polymer base material of the present invention, and by accelerating the swelling under heating, cracks occur in the metallized film. As a result, the conductive path is blocked, and when exposed to the heat inside the battery, the uniform conductive path of the current collector disappears or significantly decreases, thereby improving the safety of the battery.

Examples

[0079] An intermetallic crucible and aluminum pellets were used, and the materials used in Example 5 were placed at the deposition position of an MBraun vacuum deposition system. The chamber was degassed until it reached 3×10-5 mbar. The output was increased until the aluminum melted, and then the output was set so that the deposition rate became 3 angstroms / second. Deposition was carried out for 1 hour, and four samples were rotated on the deposition plate. This process was repeated three times, and the total deposition time was 4 hours. The weight, thickness, and electrical resistance value of the sample were measured (measured between electrodes 1 inch apart with DC and 1 kHz, one 1-inch piece), and the results are shown in Table 2 below. The electrical point resistance value was also measured using a Hioki 3555 battery HiTester at 1 kHz with the tip of the probe 1 inch apart. The weight of the added aluminum was calculated by dividing the weight added in the process by the area of the sample. This was further divided by the density of the material to obtain the average thickness of the coating.

Example

[0080] Polyethylene terephthalate microfibers with a flat cross-section were selected, and a nonwoven polymer substrate was prepared by using the process of Tappi T206 to produce a hand sheet of 20 grams / m 2 . These hand sheets were calendered at a pressure of 2,000 lbs / inch at a speed of 10 m / min using a hardened steel roll at 250 degrees (Fahrenheit). According to the process of Example 7, this material was metallized, and similar measurements were taken and the values are listed in Table 8.

Example

[0081] The material of Example 5 was deposited according to the process of Example 7, except that the coating was carried out for 60 minutes at a setting of 5 angstroms / second. The sample was turned over and the back side was coated in the same procedure. These materials were imaged with a scanning electron microscope (SEM), and the images are shown in Figures 9, 9A, and 9B.

Example

[0082] The material was prepared according to the procedure of Example 9, except that the vapor deposition on each side was only for 20 minutes.

Example

[0083] The polymer substrate of Example 8 was prepared without calendering the sheet. The aluminum vapor deposition was carried out at 5 Å / sec for 20 minutes on each side. Here, since the material was not calendered, the porosity was very high, the coating weight was thin, and a very high electrical resistance value was measured. Comparing Example 11 with Example 8 shows the surprisingly high effectiveness of the calendering process.

[0084]

Table 2

Example

[0085] The polymer substrate coated with aluminum in Example 9 was coated with an N-methyl-2-pyrrolidone solution containing 97% NCM cathode material (NCM523 obtained from BASF), 1% carbon black, and 2% PVDF binder. The coating weight was 12.7 mg / cm2 with a thickness of 71 microns. This material was cut to fit a 2032 button cell and combined with a graphite anode coated on a copper foil current collector (6 mg / cm2, 96.75% graphite (BTR), 0.75% carbon black, 1.5% SBR, and 1% CMC). The anode, separator (Celgard 2320), and NCM coating material were placed in the cell, filled with an electrolyte (60 μL, containing 1.0 M LiPF6, EC:DEC:DMC = 4:4:2 vol + 2 w.% VC), and the shell was crimped to seal the cell, thus fabricating a single-layer button cell. To obtain conductivity, a part of the polymer substrate coated with aluminum in Example 9 was left in its original state without being coated with the cathode material and was folded to contact the shell of the button cell, thereby forming a conduction path. The cell was charged at a constant current of 0.18 mA up to 4.2 V, and then charged at a constant voltage (4.2 V) until the current decreased to 0.04 mA. The cell was cycled three times at 0.37 mA between 4.2 V and 3.0 V, obtaining an average discharge capacity of 1.2 mAh.

Example

[0086] A battery was fabricated following the procedure using the materials of Example 12, except that the separator used was Dreamweaver Silver 20. The cell was charged at a constant current of 0.18 mA up to 4.2 V, and then charged at a constant voltage (4.2 V) until the current decreased to 0.04 mA. The cell was cycled three times at 0.37 mA between 4.2 V and 3.0 V, obtaining an average discharge capacity of 0.8 mAh. In this way, rechargeable lithium-ion batteries with an aluminum thickness of 1 micron were fabricated in this example and the previous examples.

[0087] Comparative Example 3 The aluminum tab of Comparative Example 1 was connected to the ground of the current source through a metal connector that contacted the entire width of the sample in a range of approximately 2 cm × 4 cm. The voltage limit was set to 4.0 V and the current limit was set to 1.0 A. The probe connected to the high voltage of the current source first hit the metal connector that contacted the entire width of the sample, and then hit the aluminum tab multiple times, resulting in a short circuit at 1.0 A. The area of the tip of the probe is approximately 0.25 mm 2 . When in contact across the entire width, the current flows normally. In the initial state when the probe hit the tab, sparks scattered, indicating a very high initial current density. The defects resulting in the current collector may cause cases such as hole formation or ablation, but the current collector itself is not damaged. In all cases, the circuit remained shorted at a current of 1.0 A. The ablation defects without hole formation were photographed under a microscope and are shown in FIG. 10. The current source limit was set to 5.0, 3.0, 0.6 A, 0.3 A, and 0.1 A, and the experiment was repeated. In all cases, when in contact across the entire width of the current collector and when using a point probe with a tip of approximately 0.25 mm 2 , the result was a continuous current at the test current limit.

[0088] Comparative Example 4 A copper tab of Comparative Example 2 having similar dimensions was tested in the same manner as Comparative Example 3. When in contact across the entire width, the current flows normally. In the initial state when the probe hit the tab, sparks scattered, indicating a very high initial current density. The defects resulting in the current collector may cause cases such as hole formation or ablation, but the current collector itself is not damaged. In all cases, the circuit remained shorted at a current of 0.8 A. The ablation defects without hole formation were photographed under a microscope and are shown in FIG. 10A. The current source limit was set to 5.0, 3.0, 0.6 A, 0.3 A, and 0.1 A, and the experiment was repeated. In all cases, when in contact across the entire width of the current collector and when the tip was approximately 0.25 mm 2In both cases when using the point probe, the result was a continuous current under the test current limit.

Example

[0089] A polymer substrate coated with aluminum having inventive step of Example 7 with similar dimensions was tested in the same manner as Comparative Examples 3 and 4. When in contact across the full width, the current flows normally. In each case, even when the probe hits directly on the current collector having inventive step, the generated sparks were quite few, the current stopped after the first spark, and the circuit remained open. In all cases, the resulting defect was a hole. Multiple examples where holes were formed were photographed under a microscope and are shown in FIGS. 11 and 11A. The current source limit was set to 5.0, 3.0, 0.6 A, 0.3 A, and 0.1 A, and the experiment was repeated. In all cases, when contacting across the full width of the connector, the current flowed continuously. In the case of contacting directly from the probe to an example of a current collector having inventive step, no current flowed through the inventive example.

[0090] In the main invention shown here, in the case of a material having inventive step, an open circuit is achieved as a result and no continuous current is seen (i.e., there is no obvious current movement). On the other hand, when short-circuited as in Comparative Examples 3 and 4 and Example 14, in the prior art, as a result, the short circuit continued. Therefore, in the prior art short circuit, heat is generated, the separator melts, the SEI layer dissolves, and as a result, thermal runaway of the battery is caused and the electrolyte catches fire. In the open circuit of the current collector having inventive step, no heat is generated. Therefore, a battery is provided that can hold an internal short circuit without allowing thermal runaway and the resulting smoke, heat, and flames.

[0091] Examples 15 and 16, Comparative Examples 5 and 6 By the roll-to-roll method, two metallized films were fabricated on a 10-micron polyethylene terephthalate film. In this method, a roll-shaped film was placed on a vacuum metallization production machine (for example, TopMet4450 available from Applied Materials), and the chamber was evacuated to a reduced pressure vacuum. The roll passed over a heated boat containing molten aluminum at a high speed, for example, 50 m / min. There was a column of aluminum gas on the heated boat containing molten aluminum, and this was deposited on the film. Here, the deposition rate is controlled by the passing speed and the aluminum temperature. The roll was passed multiple times until the aluminum coating reached a thickness of about 300 nm, and a roll with a length of about 500 m and a width of about 70 cm was fabricated. The coating process was repeated to coat the back surface of the film as well, and a product used as Example 15 was fabricated (the current collector having the inventive step in FIG. 4 shows the one used in this example). Example 16 was fabricated in the same manner except that the metal of the boat was copper (the depiction in FIG. 5B shows the current collector used in the structure having the inventive step). The basis weight, thickness, and conductivity of each film were measured, and the results are shown in Table 3. The coating weight was obtained by subtracting 13.8 grams / m, which is the basis weight of the 10-micron polyethylene terephthalate film. The "calculated coating thickness" was obtained by assuming that both sides were uniformly coated and dividing the coating weight by the material density (2.7 grams / cm for aluminum, 8.96 grams / cm for copper). 2 was obtained by subtracting. The "calculated coating thickness" was obtained by assuming that both sides were uniformly coated and dividing the coating weight by the material density (2.7 grams / cm 3 , for copper, 8.96 grams / cm 3 ).

[0092] Comparative Example 5 is a commercially available aluminum foil with a thickness of 17 microns. Comparative Example 6 is a commercially available copper foil with a thickness of 50 microns. Comparative Example 7 is a commercially available copper foil with a thickness of 9 microns.

[0093]

Table 3

[0094] For Example 15, Example 16, Comparative Example 5, and Comparative Example 6, a test was further conducted to measure whether they have the ability to carry a very high current density. A test device was prepared that holds a polished copper wire with a radius of 0.51 mm (24 AWG gauge) in contact with the current collector film or foil. The film or foil to be tested was grounded to an aluminum contact where contact with the film or foil during the test was maintained, and the contact area was 1 square centimeter. The probe was connected in series with a resistor having a high output of 400 W and a value of 0.335 ohms, and further connected to a Volteq HY3050EX power supply to control the current. A polished wire that contacts the current collector surface with zero input current was used to place the current collector to be measured. The current was increased by 0.2 amperes each time, and each time it was increased, it was held for 30 seconds while measuring the voltage across the resistor. When it was found that the voltage dropped to zero and no more current was flowing, it was found that the sample had failed. The test was conducted for each of Example 15, Example 16, Comparative Example 5, and Comparative Example 6. Example 15 failed at 7 A (average value of two measurements). Example 16 failed at 10.2 A (average value of two measurements). Neither Comparative Example 5 nor Comparative Example 6 failed below 20 A. In both Example 15 and Example 16, holes exceeding 1 mm in radius were formed in the current collector, but in Comparative Examples 5 and 6, no damage was seen in the foil. In this test example, it was advantageous to have a current collector that could not carry a current exceeding 20 A, preferably 15 A, more preferably 12 A.

[0095] In another test, a current collector having inventive step is simulated as a tab for connecting to an electronic device using an electrode stack of a battery (inside or outside the battery), and current capacity tests were performed along the test pieces for Examples 15 and 16 and Comparative Examples 5 and 6. In preparing a test sample, the current collector is cut into the shape shown in FIG. 12. Thereby, the material is cut into test pieces of 4 cm × 1 cm, and the ends thereof have the shape of a right isosceles triangle (side 4 cm) with a part cut off. Each triangle of the test piece is in contact via an aluminum piece with a contact length of less than 1 cm. One side is connected via a resistor having an output of 400 W and a value of 0.335 ohm, and the circuit is connected to a Volteq HY3050EX power supply. The voltage is measured at both ends of the resistor, and thereby the current is measured. And the timing when the voltage becomes zero was taken as the timing when the test piece failed. In each test, one piece was connected to the power supply, the power supply was set to zero current, and then increased by 0.2 A each time, and the state was maintained for 30 seconds each time the voltage changed. This was continued until the sample failed and the current flow became zero. The test was configured such that the metallized current collector was measured while in contact with one side or both sides of the metallized current collector. The current at failure is shown in Table 4. When testing the material as a 4 cm × 1 cm test piece, an internal fuse may be prepared by limiting the current to 20 A, 15 A, more preferably less than 10 A, in a state of single-sided or double-sided contact.

[0096]

Table 4

[0097] Examples 17 to 19 and Comparative Example 8 Batteries were fabricated by coating a standard foil current collector and the metallized PET film current collectors of Examples 15 and 16 with an electrode material. An NMC523 cathode material was prepared by coating an aluminum current collector (15-micron aluminum current collector) using an NMP solution containing BASF NMC523 (97%), carbon black (2%), and PVDF (1%). Example 15 has a basis weight of 220 grams / m2 and corresponds to a cathode filling density of 3.3 mAh / cm 2 An NMP solution containing graphite BTR-918S (94%), carbon black (5%), and PVDF (1%) was used and coated on a copper current collector (18-micron copper current collector) at 118 grams / m 2 to prepare the anode material. Here, 118 grams / m 2 corresponds to an anode filling density of 4.0 mAh / cm 2 Four double-sided cathodes, three double-sided anodes, and two single-sided anodes were fabricated. These were laminated together with a Celgard 2500 separator to form a small pouch cell. Then, it was filled with electrolyte and sealed at a designed capacity of 1 Ah. By varying the combination of foil materials, four types of batteries were fabricated and their capacities were measured at C / 10 and C / 5 (i.e., 0.1 A and 0.2 A). The batteries were formed by charging at 100 mA up to 4.2 V and held at 4.2 V until the current dropped to 10 mA. Subsequently, the weight of the fully formed battery was measured, discharged at C / 10, then charged at C / 10, and then discharged at C / 5 to conduct a capacity test. The results are shown in Table 5 below.

[0098]

Table 5

[0099] Therefore, the above examples show the desirable thickness, metal coating, and conductivity results required to prevent thermal runaway in a battery containing an electrolyte. Thereby, it provides components that are not only much safer and more reliable, but also have a much smaller required internal weight than before, and rather, actually have further improved safety without sacrificing safety.

[0100] As described above, the present disclosure not only provides such a thin current collector (internal fuse in a lithium battery), but also provides the advantages required for the tab structure, ensuring that the generated voltage is reliably transmitted to the outside of the target battery. Further, in the current collector described above, by utilizing the advantageous thin structure, numerous configurations within the battery itself are realized, and all of the advantageous internal fuse components can potentially generate the accumulated power level while staying in place. These points will be described in more detail with reference to FIGS. 12 to 22.

[0101] FIG. 13 shows a single thin film current tab / collector 600 having a metallized film layer 614 and a non-metallic underlayer 616. A conductive tab 610 (for transmitting external power to the battery's transfer components) is also provided perpendicular to the current collector and contacts the weld 612 there.

[0102] FIG. 14 shows a similar current collector 620. Here, a tab 622 is provided, and a tape 624 connects the tab 622 to the current collector 634 for electrical conduction. Similar to the above, the tab / current collector 620 has a metallized film layer 626 and a non-metallic underlayer 632. The tape component 622 is provided from the outer surface 628 of the tab to the non-metallic layer 626 of the current collector. This enhances the shear strength and adhesion performance of the tab, and the conductivity of the tab is maintained in a stable state.

[0103] FIG. 15 shows another tab / current collector 640. Here, the tab 642 is connected to a single thin current collector 648 (having a metallized film layer 644 and a non-metallic underlayer 650) in a different manner, and the two components are connected via a conductive staple component 646.

[0104] With such a planar current collector structure, a general battery structure can be made into a small-sized battery structure (see, for example, FIG. 1). FIG. 16 shows a single-fold 710 and a tab / current collector 700. Here, a single-tape tab 702 is provided and attached to the metallized film surface 712 (covering the non-metal layer 708 as described above). In this way, the single-fold 710 and the current collector 704 increase the power generation capacity inside the battery without increasing the battery size from the planar structure.

[0105] FIG. 17 shows a double-fold 732 and a tab / current collector 720 using a similar thin current collector 724. This double-fold 732 can further connect the two surfaces 726 and 728 of the current collector 724. Without this double-fold 732, the polymer film between the two conductive layers would electrically insulate. The tab 722 is attached to the current collector surface 730 and conducts electricity to the double-fold 732.

[0106] Similarly, FIG. 18 shows a planar tab / current collector 750 having upper surface 758 and lower surface 762 of the same type as above. In this example, tabs 752 and 754 are provided as two parallel structures and are in contact with both the upper surface 758 and the lower surface 760 of the current collector 762. Tabs 752 and 754 have welds 756 and are connected to both surfaces 758 and 760.

[0107] FIG. 19 shows a structure 780 similar to FIG. 16, where a single-fold tab 794 contacts both surfaces 788 and 790 of the current collector 792 at a predetermined position via a weld 786 having two extension prongs 782 and 784 of the folded tab 794.

[0108] FIG. 20 shows a weld 804 and a tab 802 as well as a double-fold 810 and a tab / current collector 800. As described above, the layers 808, 812 of the electrically insulated current collector 806 can be connected, but a safer weld 804 is applied at a predetermined position, enabling more reliable and potentially more effective power transmission.

[0109] Figure 21 shows a composite tab / multiple current collector structure 820 having a plurality (here, five) of folds 856 (doubly folded to be rounded) and current collectors 826, 828, 830, 832, 834 (having metallization film layers 858, 860, 862, 864, 866 and non-metallic lower layers 846, 848, 850, 852, 854). The above layers are connected in series, whereby electrical connection can be established with an electrically insulated layer via a single tab 822. The single tab 822 has a weld 824 that connects conductively with the upper current collector 826 (doubly folded to be rounded). The welded tab 822 can further improve reliability by staying in its position.

[0110] A second different weld 906 and tab 904 having a plurality of folds 938 (folded multiple times to be rounded) and a series of current collectors 908, 910, 912, 914, 916 in fixed positions are shown in Figure 22. Such a tab / current collector structure 900 can increase power generation via two tabs 902, 904 configured to connect with two external current collectors 908, 916 as described above without increasing the weight and volume of the target battery. As in the above examples of other current collectors, metallization film layers 940, 942, 944, 946, 948 are provided together with opposing non-metallic layers 928, 930, 932, 934, 936.

[0111] Referring to Figure 23, yet another non-limiting example provides a tab / current collector structure 960, a fold 972 folded in a Z shape multiple times, and a tab 962. These are (as described above) clamped in series to parallel and planar thin current collectors 964, 966, 968, 970 (here, four). Also, together with the planar thin current collectors 964, 966, 968, 970 (functioning as multiple internal fuses), metallization film layers 974, 978, 982, 986 and non-metallic lower layers 976, 980, 982, 984 can provide another way to generate cumulative series power.

[0112] Therefore, the structures shown in FIGS. 13 to 23 can allow different external connection parts for the internal fuse parts of existing lithium batteries.

[0113] Although the details of the present invention have been described, it is obvious that those skilled in the art can make various modifications and changes without departing from the scope of the present invention. Accordingly, the scope of the present invention is defined only by the appended claims.

Claims

1. An anode, A cathode, At least one separator provided between the anode and the cathode, An electrolyte, At least one thin-film current collector that contacts at least one of the anode and the cathode, At least one tab attached to at least one thin-film current collector, Comprising, The current collector includes a folded portion where a thin-film conductive material is provided on the upper and lower surfaces of a non-conductive material substrate and the end portion is folded back and folded, and a base portion excluding the folded portion, In the folded portion, the end portion is folded back in the same direction one or more times along the upper surface of the base portion, The lowermost surface of the folded portion and the upper surface of the base portion facing the surface are separated via a space, The tab is attached to at least one of the uppermost surface of the folded portion and the lower surface of the base portion facing the surface, a. The tab is attached to the current collector via welding consisting of 2 to 50 connection portions, b. The welding electrically connects between the exposed surface of the tab and the thin-film current collector and enables a uniform current flow from the anode and / or the cathode to the at least one tab, c. Either one of the anode and the cathode is interposed between at least a part of the thin-film current collector and the separator, d. At the operating voltage of the energy storage device, in the event of a short circuit, the current collector stops conduction, e. The voltage is at least 2.0 volts, A power storage device characterized by this.

2. The separator is a polymer, non-woven fabric or ceramic, The power storage device according to claim 1, characterized in that.

3. The non-conductive material substrate is a polymer film, The power storage device according to claim 1, characterized in that.

4. The electrolyte is a flammable organic electrolyte, The power storage device according to claim 1, characterized in that.

5. The folded portion of the current collector has a double-fold structure, The power storage device according to claim 1, characterized in that.

6. The current collector is a plurality of laminated current collectors, and among the plurality of current collectors, the last current collector is attached to the tab, The power storage device according to claim 5, characterized in that.

7. Further comprising a second tab attached to the first current collector among the plurality of current collectors, The power storage device according to claim 6, characterized in that the tab and the second tab are parallel to each other.

8. An anode, A cathode, At least one separator provided between the anode and the cathode, An electrolyte, At least one thin-film current collector that contacts at least one of the anode and the cathode, and a current collector that stops conduction during a short circuit at a voltage of at least 2.0 volts, which is the operating voltage of the power storage system, At least one tab attached to at least one of the thin-film current collectors, A welding configured to attach the tab to the current collector, the welding electrically connecting between the exposed surface of the tab and the thin-film current collector, Comprising, The current collector is composed of a folded portion in which a thin-film conductive material is provided on the upper and lower surfaces of a non-conductive material substrate and the ends are folded and stacked, and a base portion excluding the folded portion, In the folded portion, the ends are folded one or more times in the same direction along the upper surface of the base portion, The lowermost surface of the folded portion and the upper surface of the base portion facing the surface are separated via a space, The tab has a first tab and a second tab that are parallel to each other. The first tab contacts the conductive material on the upper surface of the current collector, and the second tab contacts the conductive material on the lower surface of the current collector, The welding consists of 2 to 50 connection portions over the entire current collector so that current flows uniformly from the electrode material to the tab, A power storage system, characterized in that either the anode or the cathode is interposed between at least a part of the thin-film current collector and the separator.

9. The power storage system according to claim 8, characterized in that the separator is a polymer, non-woven fabric or ceramic.

10. The power storage system according to claim 8, characterized in that the non-conductive material substrate is a polymer film.

11. The power storage system according to claim 8, characterized in that the electrolyte is a flammable organic electrolyte.

12. The tab is folded over the current collector such that a first prong of the tab contacts the upper surface of the current collector and a second prong of the tab contacts the lower surface of the current collector, The power storage system according to claim 8, characterized in that the first prong and the second prong are parallel to each other.

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