Apparatus, system, and method for suppressing dendrites and irregularities in electrochemical structures

Abstract

To provide a technology to suppress the growth of dendrite in batteries.SOLUTION: There are provided a method, and associated batteries and battery charging units, that involve inducing electric and / or magnetic fields across an electrode of an electrochemical cell, such as an anode of a battery. In the present specification, the field and current across the electrode may be referred to as a transverse current as this current is typically transverse to the ionic charge current that may be applied when charging a battery. The field and current may be induced from connecting AC energy, e.g., AC current, across the electrode or at a discrete point or points of the electrode. The induced field and current may suppress dendrite growth, experienced in conventional batteries without AC energy, among other advantages.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] [Cross-reference of related applications] This Patent Cooperation Treaty (PCT) application relates to and claims priority under U.S. Patent Application No. 62 / 617,103, “APPARATUS, SYSTEM AND METHOD FOR DENDRITE AND ROUGHNESS SUPPRESSION,” filed on 12 January 2018, and its entire contents are incorporated herein by reference for all purposes.

[0002] This application is also a continuation-in-part application of U.S. Nonprovisional Patent Application No. 15 / 649,633, filed on 13 July 2017, entitled “ELECTROCHEMICAL METHODS, DEVICES AND COMPOSITIONS,” and claims priority under Section 119 of the U.S. Patent Act to U.S. Provisional Patent Application No. 62 / 361,650, entitled “ELECTROCHEMICAL METHODS, DEVICES AND COMPOSITIONS,” filed on 13 July 2016. Both applications are incorporated herein by reference in their entirety for all purposes.

[0003] [Technical field] Aspects of this disclosure include electrochemistry, particularly electrochemical structures such as batteries, and methods and devices for suppressing the growth of dendrites and the like. [Background technology]

[0004] A battery typically comprises an electrochemical cell, which is a source of one or more countercharges, and a primary electrode layer separated by an ionic conductive barrier, usually a liquid or polymer membrane saturated with an electrolyte. Because these layers are made thin, multiple units can occupy the battery's volume, and each stacked unit increases the battery's available power. As these components become thinner, they become even more fragile. Furthermore, thin electrodes can cause large ohmic drops across the surface, resulting in uneven charge density during charge / discharge cycles. On top of that, battery electrodes can develop growths (or dendrites) during the battery's charging cycles, potentially further damaging the battery or degrading its performance.

[0005] For example, lithium-ion batteries typically have metal oxide electrodes (where M is typically iron, cobalt, or manganese) and carbon electrodes coated on a metal current collector. The metal oxide plays a role in attracting and stabilizing lithium during battery discharge and usually determines the cell's operating potential. The metal oxide electrodes are initially in an oxidized state, and the carbon is graphite with lithium ions implanted. During discharge (i.e., the normal use of the battery to provide power to a device), Li + Ions diffuse between the graphene layers to the graphite edge sites, and then pass through the solid electrolyte interphase (SEI). The SEI is a layer formed when lithium first reacts with the components of the organic electrolyte and consists of inorganic and organic byproducts. Because both the electronic and ionic conductivity of the SEI are lower than that of graphite and the electrolyte, respectively, the properties and quality of the SEI tend to determine the overall performance of the cell. Lithium ions continue to diffuse from the SEI through the ion transport layer toward the metal oxide, and the metal oxide becomes LiM x O y It is reduced to Li. During charging, Li +The ions follow the opposite path, instead diffusing back through the SEI and intercalating back into the carbon. Under ideal charging conditions, lithium ions can enter the graphite at the edge sites without excessive polarization that could cause plating (rate-limiting step). Plating problems arise if the cell voltage is too high, the electrodes are too polarized, or the SEI is porous, non-uniform, too thick, or too thin. In extreme cases, Li ions in dendrite formation can occur. 0 The aggregation of Li could potentially cause an explosion inside the battery. Specifically, Li 0 If the Li reaches the opposite electrode, the battery may short-circuit. 0 Dendrites formed during deposition can damage the film, potentially splitting the battery into two parts.

[0006] In the case of lithium metal electrodes, or when plating is applied to graphite electrodes, the deposits become increasingly rough with subsequent charge / discharge cycles. Both lithium metal batteries (Li foil anodes) and lithium-ion batteries (where Li ions are intercalated into graphite / foil anodes, and the current collector is often copper) have the problem of lithium dendrite growth during the battery's charge cycle. While lithium-ion anodes may remain stable for hundreds of cycles, dendrites develop quickly due to the Li metal. Once formed, they reduce the battery's Coulombic efficiency, damage the ion film, and can short-circuit the battery if the dendrites come into contact with the anode. Typically, dendrites form, puncturing or irreversibly damaging the electrolyte film. If dendrite growth reaches the opposite electrode, the battery will be permanently short-circuited and irrecoverable.

[0007] The nature of this disclosure was conceived with these issues in particular in mind. [Overview of the project]

[0008] The following embodiments and aspects are described and illustrated using systems, tools, and methods intended to be illustrative and explanatory, and are not limiting in scope. In various embodiments, one or more of the above-described problems are reduced or eliminated, and other embodiments aim at other improvements.

[0009] This specification provides methods for optimally maintaining electrodes in electrochemical cells such as batteries, regardless of whether they are charging, discharging, or in a dormant state. These methods suppress and reverse dendrite growth and control SEI quality and recovery, all of which are common causes of performance degradation and eventual failure in most batteries.

[0010] In particular, this specification provides a method for inducing an electric field and a magnetic field (field-induced current) across the entire electrode of an electrochemical cell, such as the anode of a battery. The electric field and current across the electrode may be referred to herein as a cross-current because this current crosses the ion charging current that can typically be applied when charging a battery. The electric field and current may be induced across the entire electrode or at separate or multiple points on the electrode from the connection of AC energy, such as an AC current.

[0011] In the presence of a chemical potential between the electrolyte and the electrode surface, a potential is induced across the entire electrode surface. The induced potential propagates across the entire electrode surface, causing it to charge. This electrode may be the first electrode in any method or device described herein.

[0012] Another embodiment includes a charging method in a battery comprising a first electrode and a second electrode, comprising applying a direct current (DC) charging current to one of the first electrode and the second electrode. In connection with applying the DC charging current, alternating current (AC) energy is applied to at least one of the first electrode and the second electrode. The presence of AC energy can suppress dendrite growth, among other advantages discussed herein.

[0013] Aspects of the present disclosure may further include a battery charger comprising a power source including a first conductor and a second conductor, the power source configured to apply a direct current (DC) charging current through the first conductor to one of the first and second electrodes of a battery operably coupled to the battery charger. The power source may further be configured to apply alternating current (AC) energy through the second conductor to at least one of the first and second electrodes operably coupled to the battery.

[0014] Further embodiments may include various possible battery designs incorporating a patterning layer that affects resonance, and more specifically, the overall effect of suppressing dendrite growth among the effects and benefits of the AC signal on the anode and the anode. In one example, the battery may comprise a first electrode (e.g., an anode) and an ion transport layer including a first side and a second side, the first side being operably coupled to the first electrode. The battery may further include a second electrode operably coupled to the second side of the ion transport layer, the patterning layer being operably coupled to the first electrode and configured to explicitly receive AC energy from the charge or discharge energy.

[0015] Further embodiments and features are described in part below, will become apparent to those skilled in the art by examining this specification, or can be learned by performing the embodiments discussed herein. A further understanding of certain embodiments can be achieved by referring to the remainder of the specification and drawings that form part of this disclosure.

[0016] Exemplary embodiments are shown in the referenced figures of the drawings. The disclosed embodiments and figures are intended to be illustrative and not limiting. [Brief explanation of the drawing]

[0017] [Figure 1] A cross-sectional view of the layers of a typical battery cell is depicted. [Figure 2A]Describe a cross-sectional view of the layers of a typical battery cell having common problems exemplified for a lithium metal battery. [Figure 2B] Describe the growth of dendrites in a battery cell during charging. [Figure 2C] Describe the damage to the solid electrolyte interphase layer of a battery during discharge of the battery. [Figure 3A] Describe the induction of an electrical waveform across the surface of the first electrode of a battery cell. [Figure 3B] Describe the induction of an electrical waveform across the surface of the first electrode of a battery cell. [[ID=I3]] [Figure 4] It is a flowchart of the method described. [Figure 5] Describe a comparison of plating on a copper electrode with and without a transverse current showing suppression of dendrite growth through application of the method of FIG. 4. [Figure 6] Describe a comparison between a control sample and an experimental sample of dendrite growth through application of the method of FIG. 4 to a copper electrode. [Figure 7] Describe a comparison of the peak heights of dendrites of control samples having different frequencies of transverse current and the peak heights of various experimental samples after applying the method of FIG. 4 to a copper electrode. [Figure 8] Describe a comparison of the average heights of dendrites of control samples having different frequencies of transverse current and the average heights of experimental samples after applying the method of FIG. 4 to an electrode of a battery. [Figure 9] Describe the damage to dead lithium and SEI of a battery anode due to dendrite growth on the electrode surface. [Figure 10A] Describe a general battery cell structure. [Figure 10B] Describe a general battery cell structure. [Figure 10C] Describe a general battery cell structure. [Figure 11] Describe the propagation of an electromagnetic (EM) pulse on the electrodes of a coin cell. [Figure 12] Describe the component layers of a modified coin cell battery. [Figure 13]This displays the simulation results of applying an electrical waveform along the battery electrodes.

[0018] This disclosure can be understood by referring to the following detailed description with reference to the drawings above. For the sake of clarity, certain elements in various drawings may not be drawn to the correct scale, may not be represented schematically or conceptually, or may not precisely correspond to a given physical configuration of an embodiment. [Modes for carrying out the invention]

[0019] Provided herein are methods, devices, and compositions for electrochemically joining or rearranging metals to a surface, specifically to the electrodes of a battery. Generally, the methods and devices operate by supplying an alternating current (AC) at the electrodes, such as inducing an AC current across the entire surface of the electrodes of a battery cell, and the current substantially traverses an electrochemical current, such as a DC charging current carried by ion diffusion between the anode and cathode of the battery. Generally, the electrolyte forms an electrode-electrolyte interface adjacent to the electrode surface, and a metal from the electric field comes into contact with the electrode surface to generate a current during the electrochemical process, allowing charge to pass across the interface. By inducing an AC current across the entire surface of the electrode that traverses an electrochemical current (or supplying AC energy to the electrode), electrons on the surface experience forward compression and backward expansion of their electric field. This compression and expansion generates relativistic charges that propagate from the center outward at the speed of light. Relativistic charges then bend the electric field lines of electrochemical currents (e.g., DC charging currents), directing metal or partially adsorbed atoms and particles from ions in the electrolyte to the surface of the electrode to diffuse and form more uniformly along the electrode surface. More specifically, metal ions or surface particles are directed to cracks and fissures, depressions and gaps, as well as high-aspect-ratio surface features on the electrode. As will be discussed in more detail below, this leveling effect on the electrode during the battery's charge-discharge cycle can reduce the growth potential and / or growth size and / or rate of dendrites along the battery electrode, or otherwise suppress the surface irregularities and unevenness that form on conventional battery electrodes, effectively extending battery life, improving performance, and avoiding the heat-generating events that underlie overheating, fire, and explosion.

[0020] The methods and devices described herein may operate to induce a potential across the entire surface of a battery electrode. The induced potential bends electric field lines adjacent to the surface, so that metal from the electrolyte follows the path of the bent electric field lines to deposit metal on the surface. In one specific example, the induced potential affects the electric field lines. These bent electric field lines eventually intersect at 90 degrees with respect to the portion of the surface that intersects with the surface, including surface irregularities. Alternatively, the bent electric field lines of the first current alter the trajectory of the metal from the electrolyte as the metal deposits and bonds to the surface, so that the metal is less likely to reach the entire surface at 90 degrees with respect to the microsurface of the electrode on its approach, but rather to conform to the micro-level contours and irregularities of the surface, exhibiting leveling behavior on the surface. Thus, the metal from the electrolyte is directed away from dendrite growth or other irregularities that dendrites tend to grow on. By directing the metal to this "leveling" effect, the battery electrode may resist dendrite growth, thereby preventing battery damage or inoperability.

[0021] The induced potential, more specifically the energy, of a current applied to or along the surface of an electrode can be controlled by modulating an AC waveform, including its voltage or amperage and frequency. Multiple waveforms can be combined to adjust to different features or materials present on the surface of a workpiece. In some examples, the transverse current can be modulated to direct an electrochemical process on the electrode, as the degree of dendrite growth or other irregularities on the electrode surface can be observed in real time. The processes described herein can improve the shape of the phase between the electrolyte and the electrode, referred herein as the solid electrolyte phase (SEI), by generating a horizontal or uniform SEI layer along the surface of the electrode.

[0022] Figure 1 depicts a representative cross - sectional view of the layers of a typical battery, also referred to herein as a battery cell. Generally, a battery converts chemical energy into electrical energy. As shown in Figure 1, battery 100 includes a first current collector layer 102 (which may also be called a cathode current collector), a cathode layer 104 which may be referred to as the cathode either alone or together with an adjacent current collector layer, an ion - transport media layer 106 which may be an electrolyte, an anode layer 108, and a second current collector 110 adjacent to the anode layer (which may also be called an anode current collector) which may be referred to as the anode either alone or together with an adjacent current collector layer. During operation, the anode 108 releases ions collected at the cathode 104 into the electrolyte 106. The first current collector 102 and the second current collector 110 are typically conductive metals that allow charge to pass to and from an adjacent anode or cathode. There are many different types of battery structures (including batteries with different electrolyte materials for the anode side and the cathode side of the battery), but the general operation described herein applies.

[0023] Batteries are often classified by the materials that make up the anode of battery 100 or the ion - transport layer 106. For example, lithium batteries include lithium - metal batteries (similar ones with a lithium - containing electrolyte or a lithium - foil anode) and lithium - ion batteries (similar ones with a lithium - containing electrolyte or a graphite anode containing Li + and have lithium - based anodes 108 and ion - transport layers 106. Other types of batteries, including zinc batteries and lead - acid batteries, are relevant and are known to those skilled in the art. This discussion exemplifies a lithium - ion battery (lithium intercalated in graphite), but the methods disclosed herein also apply to other battery types including lithium - metal, lithium - silicon, zinc, and lead - acid batteries. + and have lithium - based anodes 108 and ion - transport layers 106. Other types of batteries, including zinc batteries and lead - acid batteries, are relevant and are known to those skilled in the art. This discussion exemplifies a lithium - ion battery (lithium intercalated in graphite), but the methods disclosed herein also apply to other battery types including lithium - metal, lithium - silicon, zinc, and lead - acid batteries. + and have lithium - based anodes 108 and ion - transport layers 106. Other types of batteries, including zinc batteries and lead - acid batteries, are relevant and are known to those skilled in the art. This discussion exemplifies a lithium - ion battery (lithium intercalated in graphite), but the methods disclosed herein also apply to other battery types including lithium - metal, lithium - silicon, zinc, and lead - acid batteries.

[0024] When an organic electrolyte is used, lithium chemically reacts with the electrolyte, so both types of lithium batteries (among other types of batteries, including Li-silicon) form a solid electrolyte interphase at the interface between the anode 108 and the electrolyte 106. The interphase is a layer comprising reaction products of insoluble inorganic and soluble organic materials that accumulate at the interface. This layer may be referred to herein as the SEI layer, as discussed above. Generally, Li ions pass from the anode 108 through the interphase or SEI. Because the interphase generally has a high impedance, uniformity of the solid electrolyte interphase across the anode 108 can lead to a non-uniform current distribution across the anode. This non-uniformity creates channels through the interphase with high Li concentrations. These channels lead to the formation of dendrites. In other examples, irregularities along the surface of the anode 108 can also promote dendrite growth.

[0025] More specifically, dendrites typically grow during the battery's charging cycle as lithium is plated / deposited onto the anode surface 108. Electrodeposition proceeds across the interface between the two phases via a charge exchange mechanism between the polarized surface and ions with opposite charges that are decomposed or terminated within the electrolyte. The mechanism usually consists of multiple steps, and ions may undergo partial or complete charge exchange, or they may diffuse across the surface, partially adsorbed before precipitation. The growth mechanism can be distinguished as 2D (layer-by-layer type) or 3D (nucleation-combination). The proliferation of either mechanism depends on the initial state of the electrochemically activated surface, the overpotential of the driving voltage against the respective thermodynamic energy barriers, and the properties of the electrolyte.

[0026] While no two metals exhibit identical material properties and growth behavior during electrodeposition, most electrodepositions tend towards morphologies with coarser structures and increasing thickness. Apart from the influence of the electrolyte's chemical properties, low surface energy crystal planes tend to grow faster over time. Once a single crystal plane begins to dominate, the grain structure of the deposited layer can change from its originally small and randomized form to a cylindrical one. This is true for both copper and lithium, although the two have remarkably different elastic and reactive properties that influence their relative morphologies within a battery cell.

[0027] Figures 2A and 2B illustrate common problems that can occur on the electrode surface of battery 200. The battery in Figure 2A includes the same layers as the battery described above in relation to Figure 1, such as the first current collector layer 102, the cathode layer 104, the ion transport medium layer 106 or electrolyte, the anode layer 108, and the second current collector 110. The figure also shows the solid electrolyte phase 112. As shown in Figure 200, dendrites 214 grow from the anode 108 of battery 200 throughout multiple charging cycles of the battery. Figure 2B illustrates the problems caused to the effectiveness of battery 200 by the growth of dendrites 214. Specifically, dendrite growth occurs on the anode 108 during the charging of the battery. These dendrites begin to prevent lithium ions from reaching other areas on the electrode surface, thereby preventing them from participating in the reaction. These ions may also form other dendrites, further increasing the inefficiency of the battery. Limiting the growth of dendrites on the electrodes of battery 200 can improve the battery's operation and lifespan.

[0028] Another problem with batteries throughout the charging cycle is the generation of irregularities within the SEI 112, causing a weak point 218 within the SEI layer 112 between the electrolyte 106 and the anode layer 108, a problem also illustrated in Figure 2C. During battery discharge, dendrites formed on the electrode 108 can partially decompose and return to the electrolyte layer 106. However, the dendrites do not decompose uniformly, and the connection with the anode base 108 may weaken. The remaining partially decomposed lithium may lose its electrical connection to the surface and its ability to participate in the reaction. This can leave weak, thin areas in the SEI layer 112 and / or on the anode surface. The SEI 112 can immediately reform within the damaged area, causing irregularities 218 within the surface.

[0029] Referring again to Figure 2A, another common problem that arises throughout the charge-discharge cycle of battery 200 is the formation of non-conductive metal deposits 216 (sometimes known as dead lithium 216 or other inert metal deposits) within the electrolyte 106. In some examples, rough features such as mossy and fractal lithium may form along the surface of the fragile electrode 108. These growths can eventually break off from the surface 108, resulting in a loss of electrical contact. As a result, the energy potential of this metal mass is also available for power storage, and the battery capacity is permanently lost. Each of these problems can be addressed by applying an AC energy signal to or along the electrode 108.

[0030] Conventional techniques to prevent rough deposition include chemical additives known as brighteners and levelers, which are often used in the surface treatment industry for electrodeposition and electroplating. Pulsed plating and modulated signaling techniques offer improved electrodeposition and control, making the deposition more theoretically predictable and allowing for easier transport from one metallic chemical to the next. However, the benefits of these approaches to lithium systems, where the reaction rate and diffusion layer thickness depend heavily on the SEI layer, are not clearly defined. For example, pulses temporarily reverse the polarity of the electrodes to periodically re-decompose rough edges that may form before significant growth occurs (reverse pulse plating). However, when applied to batteries, pulses can interfere with the battery's output power.

[0031] These problems may be more common in certain types of batteries than in others. For example, pure lithium metal batteries have a very high energy capacity (~5-10 times) compared to lithium-ion batteries, but little is known in the technical field of how to control dendrite growth. The main obstacle preventing the commercial adoption of lithium metal batteries is the inability to regularly electrodeposit lithium onto the anode without destructive and dangerous dendrite growth, which also leads to electrolyte consumption, low Coulomb efficiency, and ultimately cell failure. Identifying potential solutions applicable to the entire range of formation factors currently required in various industries and products without compromising battery capacity or operating voltage is particularly difficult. Currently, these batteries typically only last through 10 charge-discharge cycles. Failures are often instantaneous and severe compared to typical lithium-ion batteries.

[0032] Furthermore, these problems are amplified as batteries become smaller while increasing power capacity, imposing significant design constraints. The lifespan and performance of lithium or any other chemical-based batteries can be significantly extended by increasing the smoothness and uniformity of the electrode surface using the technologies and apparatus of this disclosure. This also makes it possible to increase the recharge rate without compromising battery life, similar to conventional batteries.

[0033] This specification describes methods and devices for controlling dendrite growth on electrodes and reabsorbing the growth into the electrolyte within a battery, thereby improving the performance and lifespan of the battery. In some embodiments, the methods and devices may be operated during DC charging of the battery to inhibit or reduce dendrite formation on the battery electrodes. The methods may be performed during other operating states of the battery to provide further benefits to the lifespan and performance of the battery, such as leveling the interphase layers of the battery or decomposing the growth into the electrolyte layer. Controlling or reducing dendrite growth within a battery may also result in a relatively more durable battery. Generally, by applying an AC signal to the electrodes of a battery or the entire surface, it is possible to maintain a uniform time-averaged current distribution across the entire surface compared to the prior art which does not have such AC energy forms on the electrodes (e.g., anodes), and to more uniformly distribute the concentration of lithium ions or other charge-transfer species across the solid electrolyte phases to maintain uniform electrical behavior at the anode / electrolyte interface.

[0034] [method] Considering the aforementioned introduction and the problems and limitations of conventional processes, what is provided herein are electrochemical apparatuses and methods for controlling the deposition process on battery electrodes through electrical relaxation or surface features (e.g., dendrites) or other conductive effects. Figures 3A and 3B illustrate examples of devices for performing the methods discussed herein, and Figure 4 illustrates an example of a method according to this disclosure. Specifically, method 400 in Figure 4 may be performed during a battery charging cycle to suppress or reduce the growth of dendrites on the surface of the battery electrodes. Referring again to Figures 3A, 3B, and 4, system 300 may determine when the battery is in a charging operating state (410). Once a battery charger is connected, charging may or may not occur, and the level of charge may be greater or less, depending on the charging state or other factors. For example, in the later phases of charging, as the charge approaches 100%, the charging current may decrease. Similarly, the current drawn from the battery may depend more or less on the load on the battery. During a battery charging cycle, current may be induced across the anode (420), which may be an AC or non-DC current across the electrode surface. At lower charge or discharge levels, relatively large AC energy is applied, and therefore the induced AC energy may be charge (or discharge) dependent. At low charge or discharge levels, relatively large AC energy may be applied, and therefore the induced AC energy may be charge (or discharge) dependent. As discussed herein, the AC energy level may further be a function of the physical and material properties of a particular battery system. If the charging cycle process is incomplete (430), a transverse current along the electrode may be modulated to adjust the AC energy applied to the anode (440). For example, the application of AC energy may be adjusted based on the charge state, temperature, impedance measurement, and other feedback mechanisms. When the charging cycle process is complete, the process ends (450). In some embodiments, the AC energy may continue as reabsorption of orphan lithium, or other materials may be reabsorbed into the anode (or cathode).

[0035] Referring more closely to Figures 3A and 3B, the battery environment 300 is illustrated. Specifically, the environment 300 includes a cathode electrode 320, an anode electrode 310, and an electrolyte 340 adjacent to the cathode and anode. During battery charging, ions 324 contained in the electrolyte 340 are collected on the anode 310. Furthermore, through the described method, the power supply 360 can electrically communicate 363 with at least one contact point on the anode 310 (Figure 3A) or two or more points on the electrode (Figure 3B). The power supply 360 can therefore provide an AC energy signal or wave 350 on and / or across the surface 311 of the anode 310 through the contact point or point on the anode. A single contact point can generate a wave across the entire surface, especially if it has a path such that the current is absorbed by the electrolyte. This applied AC, which may be an AC current 350, is induced across the first electrode 310, thereby crossing a first (charging) current 330 between the cathode and anode. The second current 350 induces a relativistic charge 312 within and / or across the surface 311 of the first electrode 310. In some embodiments, the device includes a power supply 161 within a telecommunications 161 having a countercharge source 120, and within telecommunications 162, 163 having the first electrode 110. Depending on the embodiment, the power supply, which may include two or more devices, can provide and control the first current 130 and the second current 150.

[0036] More specifically, the transverse current 350 can be applied to, through and / or across, the surface 311 of the first electrode 310 to influence surface electrons without altering the design parameters of the electrolyte 340 and to induce beneficial properties in the deposition. In the presence of AC energy at the electrode, electrons on the surface 311 experience forward compression and backward expansion of their electric field. This compression and expansion generates relativistic charges 312 that propagate outward from the center of the electrons at the speed of light. These relativistic charges then bend the electric field lines of the electro / chemical reaction, which would not have bent conventionally during charging, directing the metal from the electrolyte to form on the electrode in a manner that suppresses surface irregularities. Alternatively, because the induced potential bends the electric field lines close to the surface, the metal from the electrolyte follows the path of the bent electric field lines to deposit the metal onto the surface. The bent electric field lines eventually intersect the surface at a 90-degree angle near the intersecting portion of the surface, which includes surface irregularities. The difference between deposition points under induced potential and those without induced potential is typically the shift of electric field lines toward unfilled surface gaps and rough areas. AC energy to the anode can increase many aspects of the electrodeposition process that occur in batteries during charge / discharge cycles, including but not limited to two-dimensional growth (smoothness and uniformity), grain properties such as crystallinity and morphology, induced nucleation on energetically challenging surfaces, reduced porosity within metals, adhesion to substrates, and controlled linear crystal growth.

[0037] This change in electron distribution alters the behavior of metal atoms approaching the surface. Traditionally, charge density increases around the disorder of the workpiece, then promotes a layer of metal to further increase the disorder. Instead, in the disclosed method, regions that would have a large charge density without the transverse current have a lower charge density than typical, and regions that would have a small charge density without the transverse current have a larger charge density than typical, thus promoting atoms to follow paths to produce a smooth surface. Since the frequency of the transverse current waveform can sweep several values, disorder of many sizes can be modulated. In one particular embodiment, the frequency of the transverse current waveform may be in the range of 100 Hz to 300 GHz.

[0038] [device] This disclosure also provides devices for performing the methods described herein. Specifically, a device may be used to provide an AC signal to the anode of a battery cell. The signal may be applied through a single contact point with electrode 310 or through two contact points. The device may include a current source, such as a power supply 360, to induce a current 350 along the electrode surface, as described in the exemplary methods included herein. In some embodiments, a main control unit (MCU) 363 may be included to control the current source.

[0039] The power supply may include or be associated with an MCU, which may include a processor or other computer component that communicates with memory or other tangible storage medium containing software that forms executable instructions or control sequences for performing various methods discussed herein. In the main control unit, the processor is configured to execute instructions stored in a computer-readable medium. The power modulator and power supply may be controlled by the MCU. The MCU may include one or more further electrical components for providing arbitrary signals to the battery electrodes. In some embodiments, the charging current and the AC energy connection point to the electrodes may be shared.

[0040] In yet another embodiment, the system may utilize an existing charging circuit via electrical communication to provide an AC energy signal to the battery electrodes. For example, the power supply (charging power supply) of a personal computing device (such as a mobile phone, laptop, or other battery-powered computing device) may be modified to provide an AC energy signal to the anode of a battery contained in the device. In another example, to achieve the method described herein, a vehicle battery management system (BMS) may be modified to transmit current to the battery electrodes or to discrete batteries in a larger pack. In the embodiments discussed herein, a conventional charging device may be modified with an appropriate control scheme to provide conventional DC charging by adding an AC signal applied to the anode. For example, in addition to conventional charging electronics, plugs, conductors, etc., a conductor may be configured to provide a path between the anode and the power supply portion of the charger, and the power supply may be configured to provide an AC signal to the anode under the control of an MCU.

[0041] [Dendrite relaxation] The methods described herein control the formation of various possible non-uniform, rough, and / or suboptimal surface effects, including dendrite growth and dendrite precursor growth, on electrodes(s) of many types of electrochemical structures, including but not limited to lithium metal batteries, lithium-ion batteries, lithium silicon batteries, zinc batteries, and lead-acid batteries. The methods may be performed on battery electrodes to provide several electrodynamic effects, including suppression of dendrite growth on the battery electrodes.

[0042] In certain embodiments, the method involves generating tuned waveforms and applying these waveforms to electrodes, which may be combined with a charging current to excite the surface at frequencies related to the electrode's inherent resonance or a desired pattern of induced current density. Regardless of its application environment, actual conductive surfaces tend to exhibit specific charge distributions based on their shape and inherent properties. Resistive losses attenuate the power across the surface. Current density is greater at curves or sharp points, and potential lines of the electric field ultimately approach the surface perpendicularly. For these reasons, regardless of the electrolyte, polarized electrodes will experience non-uniform charge distributions without the techniques described herein.

[0043] During conventional electrodeposition that occurs while charging a battery, electrons, for example, are uniformly dispersed tangentially to the electrode surface due to the mutual repulsion of their electric fields. However, the tangential points are not parallel, and curved features appear to concentrate the electrons. Such regions attract more metal ions, allowing dendrites to evolve. By using AC energy to shift these charges from high-energy regions to adjacent regions for statistically dominant periods, the intrinsic charge distribution of the electrode, along with the overall deposition pattern, can be altered.

[0044] Wavelength of AC (λ AC As the size of the electrode decreases and approaches the electrode length scale, the energy inherently changes from capacitive to inductive. That is, the electrode length scale ≪λ AC Using this method, a potential gradient is generated from one end to the other, from edge to edge of the surface. The magnitude of this gradient is determined by the maximum and minimum values ​​(~λ) of the waveform at the ends of each electrode. AC The maximum occurs when the electrode length scale ≫ λ. AC In this case, many points of maximum and minimum energy exist, and the rate of induction energy generation at the surface is high. This phenomenon can affect adsorption, surface and bulk diffusion, as well as nucleation processes, even when the frequency is much faster than the characteristic time of these processes.

[0045] In contrast to conventional pulse or modulation techniques at low frequencies, high-frequency AC is affected by a continuous superposition of incident or reflected energies throughout the entire system, which interacts constructively or destructively at different points along the surface. For this reason, it is not necessarily the applied transient waveform that needs to be considered, but rather the resulting standing wave pattern. Although the contribution from ions moving without an ion cloud is negligible (known as the Wien effect), frequencies above 200 MHz saturate, exceeding the relaxation time of most electrolytes. The lack of high-frequency ionic conductivity through the electrolyte forces the anode and cathode to be considered and potentially modified independently.

[0046] The electrolyte modifies the intrinsic behavior of the electrode at the interface in a predictable manner. Due to its conductivity, the electrolyte absorbs some of the AC energy, attenuating the signal with distance. This can be overcome by selecting a waveform and frequency that constructively combines the incident and reflected energies at a certain distance from the point of signal application on the electrode. For example, the incident energy can constructively couple with the reflected energy to provide a region along the electrode surface where high-energy signals reside. Furthermore, the dielectric constant of the electrolyte determines the degree of dielectric contraction of the waveform.

[0047] The amplitude of the waveform indicates a possible control parameter for the effect of AC energy on the electrode. For example, controlling the AC energy frequency or amplitude can be used to adjust the AC energy waveform applied to the electrode. The resulting standing wave can be used to keep it below the thermodynamic potential boundary in rough areas of the electrode or to exceed it in smooth areas. Similarly, the current density can be concentrated away from particularly rough areas to prevent further dendrite growth in that region. Through analysis of the electrode surface conditions, the peaks and troughs of the applied AC energy wave can be determined to select which parts of the electrode surface have higher or lower current densities. Under conditions where the frequency and amplitude are sufficiently large, the potential difference between adjacent areas of the electrode surface can induce local galvanic reactions, with or without a counter electrode. The significance of this phenomenon in decomposing dendrites and homogenizing the SEI layer in lithium-based batteries is clear.

[0048] Low-frequency AC power behaves like DC power with respect to electrodes. As the frequency of AC increases, the power concentrates near the surface according to the skin effect. In an ideal conductor, the expected skin depth is 2 mm at 1 kHz, 2 μm at 1 GHz, etc. That is, most of the AC power is concentrated in a much thinner subsection of the anode surface at high frequencies. If the interface is more complex, such as when the thickness of the irregularities and the skin depth are similar, then most of the AC power can be said to reside at the interface. Consequently, the efficiency of AC power is related to the applied frequency, and less power may be required at higher frequencies.

[0049] Several experiments were completed using copper electrodeposition as an analogue of lithium metal on battery electrodes. These tests demonstrated initial feasibility, dramatically suppressing dendrite formation in an aggressive test environment designed to generate moss-like dendrites. Control tests for dendrite generation were performed on electrode 500 using a fully saturated electrolyte solution of copper sulfate in deionized water. Additives or other methods to reduce dendrites or irregularities were intentionally excluded. The charging current density for control was ~65 mA / cm².2 The results were as follows. More specifically, Figure 5 illustrates a snapshot of 500 control samples with a surface coverage of over 60% mossy dendrites compared to identical test conditions performed using an AC signal applied to the entire electrode. As shown, with the stated charging current density, an aggressive electrolyte (low purity, reagent grade, saturated copper sulfate), oxygen-containing copper counter electrode, and excessive current density (65 mA / cm²) were used. 2 Samples were operated without AC energy (end view of sample 504 and side view of sample 506) and with AC energy (end view 508 and side view 510) under the conditions of an asymmetric cell (surface area of ​​counter electrode > working electrode) and a long deposition time (8 hours). As shown in Figures 508 and 510, this approach removed a large amount of mossy dendrite surface coating compared to the approach without AC energy (Figures 504 and 506).

[0050] Specifically, Figures 5 and 6 (and Figures 7 and 8) show the results from applying an AC signal with a frequency of 75 kHz and a power of 23 dBm to electrode 500.

[0051] A DC power supply and an AC generator were used to perform the experiments related to Figures 5 and 6. The signal from the AC generator and the negatively polarized DC power were both independently connected to a T-junction. Wires extended from this junction to the test cell. The positively polarized DC power was directly connected to the counter electrode of the test cell. The AC generator line was included inline and upstream of the T to prevent DC current from flowing into the signal generator. Similarly, the DC power supply included an AC filter inline and upstream of the T to prevent AC energy from flowing into the power supply and interfering with DC current and voltage measurements. Generally speaking, such a configuration can be used in a battery charger. The results show a dramatic reduction in the surface coverage of mossy dendrites while achieving the desired performance on the deposited mass for control results. In addition to the substantial removal of the surface coverage of mossy dendrites, the peak and mean surface heights of the deposit areas were reduced by more than 50%, as shown in Figures 7 and 8, respectively. In Figures 7 and 8, each block (for each control) illustrates the variability within each dataset represented by the block, and each figure illustrates the trend of decrease in dendrite height for each dataset for each control in each figure.

[0052] Figure 13 illustrates the simulation results of applying an electrical waveform along the battery electrodes. Specifically, sections (a)-(i) of the simulation results in Figure 13 show the results under aqueous conditions (ρ = 1.68E-8Ωm, σ soln =5S / m, ε=80) or lithium battery / organic electrolyte conditions (ρ Li =9.28E-8Ωm, σ soln The AC energy signal was generated through simulation of a conductive electrode in a material (=1 S / m, ε=45). The AC energy signal was applied along the electrode surface in a manner similar to that described herein. The conductive electrode is a foil conductor with a width of 6 mm, a thickness of 35 μm, and a triangular surface with a 1 mm undulation. A cross-sectional view of the conductor is best shown in section (d), illustrating the triangular surface undulation of the foil conductor.

[0053] Sections (a)–(c) show various AC energy signals applied to the conductor during the simulation. Specifically, section (a) shows the AC energy signal at 9.9 GHz, section (b) shows the AC energy signal at 10 GHz, and section (c) shows the AC energy signal at 100 GHz. In addition, the electric field (arrows), magnetic field (contour lines), and current density are also shown for each signal indicating the skin depth (δ) under aqueous conditions.

[0054] Section (d) shows the current density profile (grayscale) due to the DC signal (adjacent to the charging current on the electrode) and surface irregularities. Thus, section (d) shows the case where no AC signal is applied along the electrode surface. Rather, only the DC charging current is applied to the electrode. As can be seen, in this case the current density is concentrated around the points of the triangular irregularities on the electrode. It is at these points that dendrite growth is likely to continue. In other words, there are three areas of high current density at the tip of each triangular irregularity, where more current flows and as a result, dendrites grow faster in those areas.

[0055] In contrast, section (e) shows the current density profile (grayscale) from the application of an AC signal along the surface of a smooth conductor. As can be seen, the electric field and current density can be artificially manipulated by applying an AC energy signal to the electrodes. Thus, for example, using the systems and methods described herein, high-density points in conventional systems (e.g., (d)) can be dispersed away from peaks that reduce or eliminate dendrite growth. Further manipulation of the parameters of the AC signal properties can adjust the current density as needed. In section (e) (AC power), there are no triangular irregularities, and the surface is flat. Despite this fact, the systems and methods use AC energy to induce three different regions of high current density, indicated by U-shaped lines from a plane showing the behavior of the magnetic field. By manipulating the frequency and power of the AC energy, the systems can vary these lines and high current density (and deposition rate) across the electrodes.

[0056] Sections (f)–(h) show time-averaged behavior using an applied AC signal at 100 GHz. Despite the high frequency being much faster than the characteristic time (~0.1 ms–10 s) of charge transfer and convection processes, it can induce significant transient electric and magnetic field effects. The high conductivity and dielectric constant of aqueous conditions make homogenizing the current distribution using a fixed frequency difficult. In (f)–(h), where an AC signal is present, arrows represent the electric field vector and contour lines represent the magnetic field strength. More realistic conditions for lithium batteries (Li metal or Li ions) allow for a more uniform energy distribution, thus reducing the required AC power. These conditions are promising indicators that, even at high RF, AC energy is largely constrained by the electrolyte at the electrodes and interface, providing a homogenizing effect across the SEI in response to stress from interface expansion or contraction, disrupting major ion channels and helping to evolve more rapidly and uniformly. High frequencies affecting surface conductivity and inductive coupling to conductive objects that are not in direct contact provide a means of decomposing and regenerating dead lithium regardless of the battery's operating state.

[0057] In the absence of AC energy, (f) looks exactly like (d), showing high current density at the tips of the irregularities and electric field arrows where the points mainly fall straight towards the electrodes, except near rough triangles that bend the electric field lines. In (f), AC energy not only dramatically bends the electric field arrows but also randomizes the current density in the electrolyte beyond the irregularities. In this case, the roughest areas no longer grow faster than the flat areas of the electrode. In (g) and (h) with AC energy, everything is the same except that in (g) the electrode and electrolyte have the dielectric properties of a water-based chemical, while in (h) they have the dielectric properties of a lithium-ion battery with an organic electrolyte. In (g), the pattern and coloration across the entire surface are far less uniform than in (h), indicating that AC energy can be distributed more uniformly across the lithium battery electrode than in the water-based copper experiment.

[0058] Section (i) shows the current cross-sectional current distribution at a fixed frequency and an increased depth of the epidermis. Different grayscale areas show how the current density is spatially distributed as a function of frequency. As seen in this section, the current density along the electrode surface, represented by light gray and dark gray variations, is modified by the application of an AC energy signal.

[0059] [Lithium-ion intercalation] In addition to controlling and mitigating dendrites, the application of transverse AC energy / current to the electrode surface can further benefit battery operation and maintenance. For example, during charging of a lithium-ion battery, the intercalation / diffusion of lithium within the graphite becomes a rate-determining step. Rapid charging at the cell's voltage limit can potentially lead to excessive concentration polarization. Continued operation under such conditions can thicken the SEI layer, leading to increased system resistance. It is also possible that lithium may begin to plate the graphite, which rapidly leads to the same problem encountered in lithium metal batteries, starting with the formation of lithium dendrites.

[0060] AC energy and transverse current (either via transmission or directly applied conductively to the anode) can be used to excite lithium ions and increase the intercalation rate without requiring an increase in the DC voltage of the cell across the electrolyte. The conductivity along the graphene plane (σ~2.5E5S / m) is three orders of magnitude greater than the conductivity between the planes. This facilitates the propagation of energy primarily along the Li ion diffusion plane between the graphite edges, which act as points where lithium ions enter and exit. At slower frequencies (less than approximately 1000 Hz), AC energy can directly increase ion diffusion, while at higher frequencies, AC energy can function to further excite intercalated ions that have overcome the energy barriers of surface diffusion and intercalation at lower potentials throughout the cell. Applying AC energy to the electrodes, as in the pretreatment step (described later), avoids the adverse effects of concentration polarization, including thickening of the SEI and cathode breakdown. The increased intercalation rate also allows the cell to operate more intensively while reducing the risk of lithium plating initiation.

[0061] As explained above, SEI is a layer consisting of by-products formed when lithium reacts with the components of the organic electrode. It is present in all Li-ion, Li-Si, and Li-metal batteries, except those that use an inorganic film instead of an organic or electrolyte film. The layer typically has lower ionic conductivity and higher viscosity than the bulk electrolyte, and as a result, it dominates the diffusion and charge transfer processes within the cell. Due to its lower conductivity and often higher dielectric constant, AC / RF signals can propagate more uniformly across the electrode surface, resulting in less power being used for the AC / RF signals.

[0062] Ideally, the SEI (Surface-to-Electrical Integrity) is uniform across the entire electrode. However, if the electrode surface expands and contracts, or if rough features develop over battery cycles, the SEI may not adapt quickly enough, potentially resulting in some areas being thinner than others. In Li-Si batteries, this can be problematic due to the excessive strain the electrodes experience between charge-discharge cycles. Since the SEI acts as a resistance barrier for decomposed Li in the electrolyte moving to the electrode, more Li may diffuse through thinner areas of the SEI, leading to non-uniform deposition. Dominant ion transport channels also form through the SEI, potentially forming the basis for dendrites.

[0063] One way to address the thinning of SEI on battery electrodes is to apply AC energy to the electrodes. This energy can be applied to regenerate weakened areas during a charging cycle or when the battery is idle, or to level the SEI layer. Generally, the applied AC energy is partially absorbed by the SEI as it crosses the electrode surface. This induces charge transfer reactions, which can accelerate the adaptation of the SEI to the changing electrode surface shape. AC can add some mixing to the charge transfer activity, preventing the initiation of major ion transport channels. This may increase local current density, making the deposit denser and reducing its fragility, and reducing the amount of mossy or fractal dendrites that could break off from the electrode surface, thus losing electrical contact and becoming "dead lithium."

[0064] Some lithium batteries may opt for a conductive glass or polymer ion transport layer (often a membrane, but not always) instead of an organic liquid electrolyte. Without an electrolyte to react with lithium, there may be no SEI (Single-Acting Ion Ion). Dendrites pose less of a problem in this situation because the surface becomes less susceptible to their formation, or the solid ion transport layer physically prevents their continued growth onto the cathode. However, the electrode surface continues to age and degrade. In these examples, the glass or polymer layer still provides a less conductive dielectric medium, thus facilitating efficient propagation of AC energy for charge redistribution and general prevention of surface heterogeneity.

[0065] The effect of applied AC energy can be to thin or thicken the SEI, depending on the conditions and waveform parameters to address the many irregularities in the SEI layer. When AC energy is applied while the cell is neither charging nor discharging and is in a dormant state, control over one or the other is most possible.

[0066] [New electrode pretreatment for initial SEI formation] An optimally evolved SEI layer on the anode is often crucial for the performance of lithium-ion batteries. Manufacturers subject unpackaged electrode materials before distribution, and packaged electrodes after distribution, to various time and energy-intensive pretreatment steps, typically lasting several weeks. Often, these pretreatment steps involve circulation and heat, consuming significant amounts of energy and time.

[0067] Generally, the graphite in electrodes is porous and must be completely wetted with the electrolyte during the initialization phase to access the battery's pre-capacitance. However, in many applications, this becomes difficult and slow at small porosity levels below 200 nm due to the surface tension of the electrolyte. This porosity accounts for a significant portion of the graphite's total surface area. Wetting is typically achieved by heating under vacuum for several days to several weeks, making it the slowest part of the pre-treatment process. However, it is crucial for the subsequent formation of an optimal SEI layer.

[0068] Subsequently, the packaged electrodes undergo a series of slow charge-discharge cycles under a temperature-controlled program to properly evolve the initial SEI layer, which is dense, thin, electrically insulating, and consists of non-reactive and insoluble inorganic lithium species. This is known as the formation cycle. These cycles complete slowly, usually at 1 / 10–1 / 20 (0.05–0.1C) the time of a normal cycle. This contributes to a process that lasts several weeks and involves a large use of energy. These steps involve both electrodes in the cell, and the conditions required to optimize the SEI at the anode are not ideal for the cathode. The formation cycle consumes some of the cathode's lithium content, shortening the overall battery life before the cell reaches its end use.

[0069] The use of AC energy to excite the anode, as described above, provides a method to improve both the electrode wetting step and the SEI formation step in the battery manufacturing process, either in a transmissive or conductive application. AC energy, particularly at higher frequencies, exhibits remarkable behavior, inducing strong local electric field gradients as well as much higher local current densities. This type of local energy density can be used to overcome capillary forces opposing complete wetting of the graphite electrolyte, and since the energy is applied directly to the graphite, it is required to shorten or eliminate the time under vacuum and heat. Increases in local electrical and magnetic energy can also stimulate charge transfer processes in only one electrode, evolving the optimal solid electrolyte phases without polarization, depletion, or involvement.

[0070] Because the conductivity of graphite is much more parallel to the graphene plane, the energy density at the edges is relatively high at most frequencies of interest. Since this is where most chemical reactions occur and is the entry and location for intercalation of Li ions, the quality of SEI has the greatest impact on the process along the edges. Therefore, it is useful that the application of AC energy can be targeted to provide most of the benefits from an energy efficiency and propagation standpoint. Specifically, AC energy can be applied as a single electrode process to rapidly develop the initial SEI at the edges, with less concern for development elsewhere.

[0071] [Energy coupling with dead lithium] As described above, rough features can form on more fragile electrode surfaces, such as moss-like and fractal lithium. They eventually break off from the surface and lose electrical contact. Figure 9 shows such dead lithium in the electrolyte layer 108 of a battery due to fragile dendrite growth on the anode 108. The stored energy potential of this lithium clump cannot be used for power storage, and the battery capacity is permanently lost once such clumps form.

[0072] A method for supplying AC energy to the anode 108 can help decompose these dead lithium clumps into electrolyte 1906, thereby restoring the energy potential of battery 100. Specifically, AC energy can nonconductively induce charge in the dead lithium, which initiates decomposition into electrolyte 106. Depending on the frequency, capacitive or inductive coupling may occur near the surface. Closest to the surface, electrical or magnetic energy is dominant, with most of the energy reacting. Where the dead material is farther from the surface, the energy transfer mechanism is dominated by more coherently radiated energy. These two mechanisms roughly correspond to the near- and far-field regions of the radiator, respectively. Even in the case of radiated energy, the dead matter has a unique near-surface coupling phenomenon that yields reaction energy. By inducing an electric current in the dead matter, the local current density can be increased sufficiently for charge transfer processes and dissolution. In the decomposed state, the matter becomes accessible again for energy storage.

[0073] Reabsorption can be monitored in various ways. For example, storage capacity can be monitored in each consecutive cycle using AC energy applied during and / or explicitly applied over various charge and discharge cycles. In some examples, capacity may be compared to the storage capacity value initially set or measured when the battery was operational, or to the trend of measurements over time (e.g., a decrease in capacity or a clear decrease in capacity over time compared to an increase in capacity after reabsorption). Reabsorption can also be determined based on cell resistance, with a decrease in resistance relative to the previously measured value indicating the reabsorption of dead material present at the time of the previously measured value.

[0074] [Single contact point] Batteries traditionally have electrodes and only one point of electrical contact. For example, Figures 10A–10C show three common cell or battery configurations and externally accessible electrical contact points. In particular, Figure 10A shows a top view of a pouch cell 1002 including electrode sheets and an ion transport layer cut to specific dimensions. The electrode cutouts include tabs 1004 that can be accessed to provide electrical contact. In some cases, additional tabs may be added at different points to enable multiple contact points as needed. However, typically, there is only a single electrical contact point 1004 per electrode. In the example shown, the first tab 1004(A) is for the counter electrode and the second tab 1004(B) is for the working electrode (e.g., the anode). AC energy can be coupled at tab 1004(B) or tab 1004(C) can provide a connection point to the working electrode. Alternatively, AC energy may be applied across or between tabs on the same electrode, such that an AC(+) connection is made on one tab and an AC(C) connection is made on the other tab.

[0075] Figure 10B shows a typical cross-sectional view of a coin or button cell 1006 containing standard layers within a "can". The top and bottom of the can are electrically insulated from each other by a gasket 1008. A single electrical contact point 1010 is created by contact between the bottom and the can at any point within the area. The can is in direct electrical contact with the current collector layer (typically aluminum at the cathode and copper at the anode). Figure 10C illustrates a "jelly roll" cell 1012 based on rolled multilayer cells, most similar to a pouch cell 1002. However, the packaging is typically limited to a single point of electrical contact per electrode, 1014(A) and 1014(B), similar to a coin cell.

[0076] While a battery provides a single contact point to the anode, the AC energy discussed herein can still be applied to achieve the battery's performance outcomes. For example, Figure 11 shows a single contact point providing AC energy to the anode 1106 of a coin or button cell 1008. The 3D diagram shows EM pulses (1108 and 1110) propagating across the entire anode surface from different single contact points (A - centrally located 1102, B - offset 1104) at different times. Generally, when wavelength ≥ anode diameter, the location of the contact point is less important. When wavelength ≤ anode diameter, reflections along the electrode boundary contribute to more complex patterns and standing waves across the surface. Therefore, since batteries are often limited to a single contact point, the influence on the standing AC waves generated based on the location of the single contact point on the anode is considered.

[0077] [RF signals to be transmitted] Instead of being conducted through a source in direct electrical contact, AC / RF can be transmitted to electrodes over a distance to induce benefits similar to those described herein. In this case, the directivity of the transmitter and the orientation of the electrodes in the radiating field are primary considerations. In some embodiments, such as large battery packs, access to the anode is limited or difficult. In such situations, strategically placed transmitters may be positioned throughout the battery pack to radiate AC signals to the electrodes of cells within the battery pack. Depending on the situation, shielded or directional antennas may be positioned to shield the cathode in situations where only the anode is targeted, or solely to direct energy towards the anode.

[0078] [Independent modulation of the anode and cathode] In some cases, the AC signal may not necessarily be applied proportionally or inversely to both the anode and cathode of the battery. Rather, the signal input at the cathode may affect the anode through conductance, coupling, or transmission (depending on the frequency), and vice versa. In such cases, AC energy can be used to cause battery recovery (homogenization of the electrode / electrolyte interface), whether the battery is active or dormant. Homogenization can occur at the electrodes regardless of whether the battery is charging, discharging, or dormant, if the AC signal is sufficient to induce local diffusion and charge transfer processes.

[0079] The frequency and power of the AC energy should be selected to achieve the desired effect (dendrite prevention, SEI thinning or thickening, ion intercalation, etc.) in the most energy-efficient way possible. Overall process efficiency is critical for battery charging, and in most applications, even a slight decrease in efficiency can have a significant impact on the application. Calculating overall efficiency requires combining the energy input between both electrodes (DC, standard) and the energy used for AC energy as a ratio to storage capacity, lifespan (total cycles), or a similar battery metric. In one example, AC can increase ion intercalation and reduce the required galvanic potential. In another example, AC energy improves the recovery rate of SEI to follow changes in electrode structure, increasing battery life. The benefits of additional energy to the AC signal should, in some cases, be weighed against these results.

[0080] Especially in large-scale systems such as EV battery packs or fixed applications, the energy requirements of the DC input are already high in situations involving fast charging (the relative additional load on the system may be low), so the additional energy for the AC input may be more tolerant. During charging, the AC input may be intended to inhibit dendrite formation and the development of non-uniform porosity in the SEI (including ion channels), as well as to increase lithium diffusion without raising the cell potential. It can also regulate SEI growth and prevent the layer from becoming too thick. Since the cell is discharging, the stimulating ion diffusion from the graphite remains beneficial.

[0081] The AC energy applied during discharge or when the cell is idle also provides a gentler environment for SEI to recover (reshape in areas of electrode deformation or to become denser again after conditions that made the SEI porous), and may regain uniformity after aggressive charging cycles or operating conditions. Furthermore, dead lithium and existing dendrites may decompose at any of these stages.

[0082] [Electric flow and diffusion effect] The electrodynamic behavior of AC energy propagating throughout the electrode can produce electrokinetic effects at the electrode|electrolyte, electrode|SEI, SEI, and SEI|electrolyte interfaces. The nature of these effects depends on the material properties of one layer relative to other layers at the interface. For example, high frequencies far exceeding conventional considerations, such as 100 GHz, can alter the steady-state diffusion pattern of the electrolyte near the electrode surface when applied. The exact pattern depends on the frequency.

[0083] As previously discussed, the magnitude of local charge density, electron paths, and local electric field gradient all depend on frequency and generally increase proportionally. Exceptions can occur under certain conditions of resonance (where the energy becomes essentially capacitive or inductive) or energy absorption by the surrounding environment. When the applied frequency is slower than the charge relaxation time of the layers, the conductive mechanism dominates the passage of charge to and from the interface. If conductivity is dominant in one layer but not in the other, the interface becomes polarized. When the applied frequency is faster than the charge relaxation time of the layers, the interfacial polarization is proportional to the difference in dielectric constants between the two layers.

[0084] The fundamental behavior of any interface in response to AC energy can be estimated based on the general guidelines above and the relative properties of all layers. This can serve as the simplest basis for beginning to determine the appropriate waveform to achieve the following specific effects. • Electrode (lithium): High conductivity, low dielectric constant SEI: Low conductivity, moderate dielectric constant • Organic electrolytes: moderate conductivity, medium-high dielectric constant Regardless of the interface considered, at frequencies approaching or exceeding resonance across the entire dimensions or characteristics of the interface, the effects are mixed and spatially dependent—i.e., localized. Precise frequencies and powers can induce dielectrophoretic forces generated by diffusion patterns at or near the surface. In other words, the frequency and power of a given AC energy application may be based on differences in the electrical and dielectric properties of the materials within the battery.

[0085] [Designed battery cells] In the cases discussed so far, the nature of the applied energy and the mechanism of its influence on diffusion and charge transfer processes may depend on the relationship between the applied wavelength and the dimensions of the electrodes. Specifically, how it resonates depends on the electrodes or characteristics on the electrodes at the applied frequency. This is a suitable focus for battery systems where the electrochemical behavior needs to be modified by process without changing the cell shape or design.

[0086] If it is possible to redesign the battery, a resonant layer tuned (patterned) to guide or form the energy applied to the electrode surface can be added close to the electrodes. For example, Figure 12 shows the component layers of a coin cell battery configuration 1200. In this fabricated cell, the anode 1202 is modified by a dielectric layer 1204 and a conductive / patterned layer 1206 for electrical coupling with the primary conductive layer. Exemplary patterned layers A-C 1218-1212 show various patterned layers that may be included in the coin cell 1200. As shown, the shape of patterned layer 1208 matches the primary layer in Example A. In Example B, patterned layer 1210 includes a ring for stronger coupling with magnetic energy. In Example C, patterned layer 1212 includes a complex shape to control the resonant frequency and induce a unique pattern of current density at the main electrode. In general, the patterned layer 1206 can take any shape and size to form or generate the AC wave applied to the anode of the cell.

[0087] In the case of a modified battery cell, DC energy may be applied to the primary conductive layer 1202 in contact with the electrodes while AC is applied to the patterned layer 1206. The patterned layer 1206 is designed with a specific conductive path having desired resonant behavior, which may or may not be similar to that of the primary conductive layer. A given battery layer, particularly the battery electrodes, resonates based on the dimensions and material properties of the layer. The patterned layer can be tuned to resonate and made to interact with the target battery layer to influence the overall resonance in the presence of an AC signal. In one example, computer simulations may be used to develop specific patterns for any given application and to adjust or tune the pattern of the overall intended effect, such as dendrite suppression. The AC energy applied to a carefully patterned conductive layer can be made to flow in a specific direction that does not necessarily coincide with the pattern. If the patterned layer is separated from the electrodes by a thin dielectric layer, the electric and magnetic fields resulting from the AC energy of the patterned layer pass through the dielectric layer and influence the electric and magnetic fields of the disk electrodes.

[0088] In another case, the primary conductive layer 1202 can be connected to the patterned conductive layer 1206 through the dielectric layer or via one or more conductive channels around it, so that DC and AC can be applied to a single point and reach both layers. In this case, the resonant behavior of the primary conductive layer 1202 is modified and perhaps dominated by coupling with the patterned layer 1206. The patterned layer 1206 can also still influence the electrochemical process of the primary conductive layer 1202 when only the primary conductive layer receives DC and / or AC conductive inputs.

[0089] As described above, the patterning layer can take many forms. The resonant behavior of Example A1208 is regulated even if the primary layer changes during battery operation. Coupling occurs throughout the dielectric layer within the conductive layer. This allows the AC signal to propagate more uniformly without attenuation caused by the conductive electrolyte. In another example, the patterning layer may be a closed loop that couples more strongly with the magnetic energy at the applied AC frequency, as in Example B1210.

[0090] In another example, the patterned layer may have a complex shape that shifts the strongest capacitive-inductive transitions (e.g., shifting the resonance point to a lower frequency). The shape may also induce a specific patterned region of electromagnetic behavior on the primary conductive layer (e.g., C1212). In one very specific case, the pattern may influence a disguised surface plasmon polariton that induces a current displacement directional pattern. The patterned layer may not receive a direct conductive input, but instead may influence the electrochemical processes in the primary conductive layer entirely through coupling.

[0091] [Other battery types] Zinc batteries have an energy capacity similar to or greater than that of lithium-ion batteries (particularly zinc-air batteries). Both zinc and lithium are negative metals and face similar problems to dendrites when used in batteries. The main difference is that zinc can be used in aqueous (usually alkaline) solutions. Dendrites are also a major obstacle to the ability of Zn electrons to circulate in rechargeable zinc batteries. They form easily and can damage or short-circuit the anode and cathode. Dendrite suppression can be achieved by using organic additives in the electrolyte, which eventually co-deposit and deplete on the electrodes. Small concentrations of various metals or metal oxides can be added to affect the degree of decomposition and mobility of reversible by-products, maintaining a more uniform surface during cycling. To prevent the need for these types of additives, the processes and methods described herein may be used to suppress dendrite formation and homogenize the surface of the zinc electrodes in rechargeable zinc batteries.

[0092] With respect to lead-acid batteries, the methods described herein may be modified to constitute an electrochemical cell and its electrochemical composition. Unlike lithium-based batteries, the plating on both the anode and cathode corrodes during charging and discharging. Since existing cells have only two ports, the cross-current is transmitted through one port, which is calculated to reflect off the far wall of the cell and return to the inlet port. Thus, the waveform of the cross-current is swept through several frequencies to achieve a relatively balanced time-averaged current distribution across the anode and cathode surfaces of the lead-acid battery.

[0093] While several embodiments have been described, those skilled in the art will recognize that various modifications, alternative structures, and equivalents can be used without departing from the spirit of this disclosure. Furthermore, some well-known processes and elements have not been described in order to avoid unnecessarily obscuring the disclosed embodiments. Therefore, the above description should not be construed as limiting the translation.

[0094] Those skilled in the art should understand that the disclosed embodiments are taught as examples, not as limitations. Therefore, the matters shown in the above description or drawings should be interpreted as illustrative, not limiting. These claims must encompass all general and specific functions described, and all descriptions of current methods and systems, which lies somewhere in the language.

Claims

1. The first electrode and An ion transport layer comprising a first side and a second side, wherein the first side is operably coupled to the first electrode, A second electrode operably coupled to the second side surface of the ion transport layer, A patterning layer operably coupled to the first electrode, wherein the patterning layer has a pattern feature portion on its surface, and the pattern feature portion is configured to guide the AC energy applied to the patterning layer to the surface of the first electrode based on the pattern feature portion, The dielectric layer between the first electrode and the patterning layer, A battery equipped with a battery.

2. The battery according to claim 1, wherein the first electrode is an anode.

3. The battery according to claim 2, further comprising a solid electrolyte interface (SEI) layer between the anode and the ion transport layer.

4. The battery according to claim 1, wherein the patterning layer affects the resonance of the AC energy along the surface of the first electrode.

5. The battery according to claim 1, wherein the ion transport layer is an electrolyte.

6. The battery according to claim 1, wherein the ion transport layer includes an interface.

7. The battery according to claim 1, wherein the AC energy is an AC current or AC voltage, and the AC energy is different from the charging or discharging energy.

8. The first electrode and A patterning layer operably coupled to the first electrode, wherein the patterning layer has a pattern feature portion on its surface, the pattern feature portion induces AC energy applied to the patterning layer, and the pattern feature portion influences the resonance of the AC energy along the surface of the first electrode based on the pattern feature portion, The second electrode and A dielectric layer located between the first electrode and the patterning layer, A battery equipped with a battery.

9. The battery according to claim 8, wherein the patterned layer is configured to receive alternating current energy different from charging energy or discharging energy.

10. The battery according to claim 9, wherein the first electrode is an anode or a cathode.

11. The battery according to claim 9, wherein the charging energy is a controlled current or voltage applied to the first electrode.

12. The battery according to claim 8, wherein the patterned layer includes a ring.

13. An ion transport layer comprising a first side and a second side, wherein the first side is operably coupled to the first electrode, further comprising an ion transport layer, The battery according to claim 8, wherein the second electrode is operably coupled to the second side surface of the ion transport layer.

14. The battery according to claim 13, wherein the ion transport layer includes an electrolyte.

15. The battery according to claim 14, further comprising a solid electrolyte interface (SEI) layer between the first electrode and the ion transport layer.

16. The battery according to claim 8, wherein the AC energy is AC current or AC voltage.

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