Electrochemical cells and stack of electrochemical cells having series connections and methods for producing, operating and

Abstract

In some aspects, a method of monitoring a health of an electrochemical cell may include: measuring a first anode voltage at a first anode tab from a plurality of anode tabs, and measuring a second anode voltage at a second anode tab from the plurality of anode tabs; measuring a first cathode voltage at a first cathode tab from the plurality of cathode tabs, and measuring a second cathode voltage at a second cathode tab from the plurality of cathode tabs; and calculating a first sense voltage, the first sense voltage being a difference between the first cathode voltage and the first anode voltage. In some embodiments, a second sense voltage may be calculated, the second sense voltage being a difference between the second cathode voltage and the second anode voltage. In some embodiments, a difference between the first sense voltage and the second sense voltage may be calculated.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 394,341, filed on August 2, 2022, entitled “Electrochemical Cells and Electrochemical Cell Stacks with Series Connections and Methods of Producing, Operating, and Monitoring the Same”; the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments described herein relate to series-connected electrochemical cells and methods of producing, operating, and monitoring the same. Background Art

[0004] In lithium-ion batteries containing multiple electrochemical cells electrically connected in series, it is desirable to monitor and balance the voltage of each electrochemical cell to optimize the overall performance of the battery. The voltage of each electrochemical cell is monitored to assess the health of the battery and to ensure that the voltage does not exceed the set limit during battery charging and discharging. Due to differences between batteries, electrochemical cells are also regularly balanced, which involves removing charge from the battery or adding charge to the battery to ensure that the voltages across the cells do not deviate significantly from each other, as significant deviations in voltage can reduce the performance of the battery. In typical state-of-the-art lithium-ion batteries, monitoring and balancing of individual electrochemical cells are performed through the same electrical connection point, thereby excluding the ability to monitor and balance electrochemical cells simultaneously. In addition, when the voltage is sensed through a connection point that also carries the system current, the measured voltage may have a voltage offset proportional to the system current flow. The voltage offset caused by the current flow may cause errors that must be considered in filtering and monitoring algorithms. In addition, in electrochemical cells with large area electrodes, there may be an intra-electrode voltage gradient, which affects the voltage measured at a single reference point, thereby reducing the effectiveness of existing balancing and monitoring algorithms.

[0006] Therefore, there is a need for a mechanism by which series-connected electrochemical cells can be more accurately and efficiently monitored and balanced. Summary of the invention

[0005] Embodiments described herein relate to methods of producing, operating, and monitoring electrochemical cells connected in series. In some aspects, a method of operating an electrochemical cell included in an electrochemical cell stack having a plurality of electrochemical cells, each of the electrochemical cells in the electrochemical cell stack including an anode material coupled to an anode current collector having a plurality of anode tabs, a cathode material coupled to a cathode current collector having a plurality of cathode tabs, and a separator disposed between the anode material and the cathode material, the method comprising: measuring an anode voltage difference between a first anode tab from the plurality of anode tabs and a second anode tab from the plurality of anode tabs of the electrochemical cell; measuring a cathode voltage difference between a first cathode tab from the plurality of cathode tabs and a second cathode tab from the plurality of cathode tabs of the electrochemical cell; and balancing the electrochemical cell relative to other electrochemical cells included in the electrochemical cell stack based at least on the values ​​of the anode voltage difference and the cathode voltage difference. In some aspects, a method of monitoring the health of an electrochemical cell may include: measuring a first anode voltage at a first anode tab from a plurality of anode tabs and measuring a second anode voltage at a second anode tab from the plurality of anode tabs; measuring a first cathode voltage at a first cathode tab from a plurality of cathode tabs and measuring a second cathode voltage at a second cathode tab from the plurality of cathode tabs; and calculating a first sensing voltage, the first sensing voltage being the difference between the first cathode voltage and the first anode voltage. In some embodiments, a second sensing voltage may be calculated, the second sensing voltage being the difference between the second cathode voltage and the second anode voltage. In some embodiments, the difference between the first sensing voltage and the second sensing voltage may be calculated.

[0006] In some aspects, an electrochemical cell may include: an anode material coupled to an anode current collector; a cathode material coupled to a cathode current collector; a separator disposed between the anode material and the cathode material; a plurality of anode tabs electrically connected to the anode current collector such that a first anode voltage can be measured at a first anode tab from the plurality of anode tabs and a second anode voltage can be measured at a second anode tab from the plurality of anode tabs; and a plurality of cathode tabs electrically connected to the cathode current collector such that a first cathode voltage can be measured at a first cathode tab from the plurality of cathode tabs and a second cathode voltage can be measured at a second cathode tab from the plurality of cathode tabs. In some embodiments, the first cathode tab and the first anode tab extend from a proximal end of the electrochemical cell. In some embodiments, the second cathode tab extends from a first horizontal side of the electrochemical cell and the second anode tab extends from a second horizontal side of the electrochemical cell, the second horizontal side being opposite the first horizontal side. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of an electrochemical cell stack according to an embodiment.

[0008] Figure 2 is a block diagram of an electrochemical cell according to an embodiment.

[0009] Figure 3 An electrochemical cell according to an embodiment is shown.

[0010] Figure 4 An electrochemical cell according to an embodiment is shown.

[0011] Figure 5 is a schematic flow chart of a method of monitoring the health of an electrochemical cell according to an embodiment. DETAILED DESCRIPTION

[0012] Embodiments described herein relate to methods for producing, operating, and monitoring electrochemical cells. Some embodiments described herein may be used to monitor electrochemical cells connected in series. In systems including multiple electrochemical cells connected in series, such as lithium-ion batteries, electrochemical cell voltages are typically monitored and balanced to optimize battery performance. The voltage of each electrochemical cell is monitored to assess the health of each electrochemical cell and to ensure that the voltage of each electrochemical cell does not exceed set limits during charge and discharge. In addition, since electrochemical cells may differ from one another due to minor variations in materials and manufacturing, electrochemical cells may be periodically balanced to eliminate differences in voltage between electrochemical cells, which may reduce the overall performance of the battery. In electrochemical cells with large area electrodes, intra-electrode voltage gradients may exist, which may affect the voltage measured at any single reference point and complicate monitoring and balancing. In existing methods, (1) individual electrochemical cells are monitored and balanced through the same electrical connection point, which precludes the ability to monitor and balance electrochemical cells simultaneously, and (2) intra-electrode voltage gradients are estimated using complex algorithms, the accuracy of which may be affected by various factors such as cell aging.

[0013] The embodiments described herein can address the shortcomings of existing methods by including multiple locations where the voltage of an electrochemical cell can be measured. In some embodiments, multiple anode tabs and multiple cathode tabs can be used to measure the voltage of an electrochemical cell at different locations along the anode and cathode, respectively, thereby allowing the intra-electrode gradient to be measured directly instead of using an algorithm to estimate the intra-electrode gradient. In addition, including multiple anode tabs and multiple cathode tabs enables simultaneous monitoring and balancing of any one electrochemical cell, thereby reducing the steps required in the production or operation of the battery. For example, balancing the electrochemical cell voltage can be performed by a first anode tab and a first cathode tab, while monitoring the electrochemical cell can be performed by a second anode tab and a second cathode tab. Independently monitoring changes in voltage (e.g., changes relative to current flow in the system) can enable additional diagnostic functions that are not available in the most advanced systems currently. Additional anode tabs and / or cathode tabs as described herein can be used as local connections for a battery management system (BMS) in large battery cells and smaller battery cells, and eliminate the need for long connection wires. Therefore, the systems and methods described herein can provide additional advantages in terms of packaging and line length, particularly for large battery cells. Additionally, including multiple anode and cathode tabs can provide additional paths for monitoring electrochemical cells that are separate from the system's current path. Monitoring the voltage at various points throughout a cell or electrode can be an important aspect of building an energy storage system. Current cell algorithms assume that electrochemical cells are essentially uniform and function as homogeneous entities. Identifying differences in voltage gradients or inflection points can help identify problematic cells or electrodes. Identifying these faulty elements during production or even during operation can significantly limit the downtime of the energy storage system during repair or replacement.

[0014] The embodiments described herein may include algorithms for detecting cell-level faults, internal short circuits, and other fault modes using sensors. Sensing may be used to sense or determine cell voltage, temperature, current, module-level voltage, module-level temperature, module-level current, battery pack-level voltage, battery pack-level temperature, and / or battery pack-level current. The algorithm may then be used to diagnose the functional state of each battery cell in the system. In some cases, sensing may be accomplished via BMS, test system sensing, auxiliary sensing systems, or any combination thereof. The safety system may include regional temperature (hot spots), fire detection, smoke detection, hydrogen detection, carbon monoxide (CO) detection, carbon dioxide (CO2) detection, volatile organic compound (VOC) detection, or other detection methods to ensure that the system is not damaged or to prevent damage to the system, battery, and facilities during formation. The safety system may include a fire extinguishing system for preventing damage to facilities, an active ventilation system for preventing damage to facilities and personal injury, and a protection system for providing transmission protection between cells, modules, and / or battery packs in formation.

[0015] In some embodiments, the electrodes described herein may include conventional solid electrodes. In some embodiments, the solid electrodes may include a binder. In some embodiments, the electrodes described herein may include semi-solid electrodes. The semi-solid electrodes described herein may be made: (i) thicker than conventional electrodes (e.g., greater than 100 μm to up to 2,000 μm or even greater) due to the reduced tortuosity and higher conductivity of the semi-solid electrodes, (ii) with a higher active material loading, and (iii) with a simplified manufacturing process using less equipment. These relatively thick semi-solid electrodes reduce the volume, mass, and cost contribution of inactive components relative to active components, thereby enhancing the commercial appeal of batteries made from semi-solid electrodes. In some embodiments, the semi-solid electrodes described herein are binder-free and / or do not use binders used in conventional battery manufacturing. Instead, the volume of the electrode that is typically occupied by the binder in a conventional electrode is now occupied by: 1) electrolyte, which has the effect of reducing tortuosity and increasing the total salt available for ion diffusion, thereby offsetting the typical salt depletion effect of thick conventional electrodes when used at high rates, 2) active material, which has the effect of increasing the charge capacity of the battery, or 3) conductive additive, which has the effect of increasing the electronic conductivity of the electrode, thereby offsetting the high internal impedance of thick conventional electrodes. The reduced tortuosity and higher electronic conductivity of the semi-solid electrodes described herein produce excellent rate performance and charge capacity of electrochemical cells formed by semi-solid electrodes. Since the semi-solid electrodes described herein can be made much thicker than conventional electrodes, the ratio of active materials (i.e., semi-solid cathodes and / or anodes) to inactive materials (i.e., current collectors and separators) in the battery formed by the electrochemical cell stack including the semi-solid electrodes can be much higher relative to similar batteries formed by the electrochemical cell stack including conventional electrodes. This significantly increases the total charge capacity and energy density of the battery including the semi-solid electrodes described herein.

[0016] In some embodiments, the electrode materials described herein can be flowable semi-solid or condensed liquid compositions. In some embodiments, the electrode materials described herein can be binder-free or substantially binder-free. A flowable semi-solid electrode can include a suspension of an electrochemically active material (anode or cathode particles or microparticles) and an optional electronically conductive material (e.g., carbon) in a non-aqueous liquid electrolyte. In other words, the active electrode particles and the conductive particles are co-suspended in an electrolyte to produce a semi-solid electrode. Examples of cell architectures utilizing semisolid suspensions are described in U.S. Patent Publication No. 2022 / 0238923, filed on January 21, 2022, and entitled “Production of Semi-Solid Electrodes Via Addition of Electrolyte to Mixture of Active Material, Conductive Material, and Electrolyte Solvent” (“the '923 Publication”) and Provisional Patent Application No. 63 / 354,056, filed on June 21, 2022, and entitled “Electrochemical Cells with High-Viscosity Semi-solid Electrodes, and Methods of Making the Same” (“the '056 Application”), the entire disclosures of which are incorporated herein by reference.

[0017] In some embodiments, the power management system described herein may include any of the aspects described in: U.S. Patent No. 10,153,651, filed on October 9, 2015 and entitled “Systems and Methods for Battery Charging” (“the '651 patent”), the disclosure of which is incorporated herein by reference in its entirety. In some embodiments, the battery management system described herein may include any of the aspects described in: U.S. Patent Application No. 17 / 743,631, filed on November 20, 2020 and entitled “Electrochemical Cells Connected in Series in a Single Pouch and Methods of Making the Same” (“the '631 application”), the disclosure of which is incorporated herein by reference in its entirety.

[0018] As used in this specification, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, the term "member" is intended to mean a single member or a combination of members, and "material" is intended to mean one or more materials or a combination thereof.

[0019] When used in conjunction with "cylindrical," "linear," and / or other geometric relationships, the term "substantially" is intended to convey that the structure so defined is nominally cylindrical, linear, etc. As an example, a portion of a support member described as "substantially linear" is intended to convey that while linearity of the portion is desired, some nonlinearity may occur in the "substantially linear" portion. Such nonlinearity may result from manufacturing tolerances or other practical considerations, such as, for example, pressure or forces applied to the support member. Thus, a geometric structure modified by the term "substantially" includes such geometric properties within a tolerance range of plus or minus 5% of the geometric structure. For example, a "substantially linear" portion is a portion that defines an axis or centerline whose linearity error is within plus or minus 5%.

[0020] As used herein, the terms "group" and "plurality" may refer to multiple features or a single feature having multiple parts. For example, when referring to a group of electrodes, the group of electrodes may be considered to be one electrode having multiple parts, or the group of electrodes may be considered to be multiple different electrodes. In addition, for example, when referring to multiple electrochemical cells, the multiple electrochemical cells may be considered to be multiple different electrochemical cells or to be one electrochemical cell having multiple parts. Thus, a group of parts or multiple parts may include multiple parts that are continuous or discontinuous with each other. Multiple particles or multiple materials may also be made from multiple items that are produced separately and subsequently joined together (e.g., via mixing, adhesives, or any suitable method).

[0021] As used herein, the term "semisolid" refers to a material that is a mixture of a liquid phase and a solid phase, such as, for example, a particle suspension, a slurry, a colloidal suspension, an emulsion, a gel, or a micelle.

[0022] As used herein, the terms "activated carbon network" and "networked carbon" refer to the general qualitative state of an electrode. For example, an electrode having an activated carbon network (or networked carbon) causes the carbon particles within the electrode to present individual particle morphology and arrangement relative to each other, which promotes electrical contact and conductivity between particles and across the thickness and length of the electrode. In contrast, the terms "unactivated carbon network" and "unnetworked carbon" refer to electrodes in which carbon particles exist as individual particle islands or multi-particle aggregate islands, which may not be sufficiently connected to provide sufficient electrical conduction through the electrode.

[0023] As used herein, the terms "energy density" and "volume energy density" refer to the amount of energy (e.g., MJ) stored in an electrochemical cell per unit volume (e.g., L) of materials (such as electrodes, separators, electrolytes, and current collectors) included for the operation of the electrochemical cell. Specifically, the materials used to package the electrochemical cell are excluded from the calculation of volumetric energy density.

[0024] As used herein, the term "high capacity material" or "high capacity anode material" refers to a material with an irreversible capacity greater than 300 mAh / g, which can be incorporated into an electrode to promote the absorption of electroactive species. Examples include tin, tin alloys such as Sn-Fe, tin oxide, silicon, silicon alloys such as Si-Co, silicon oxide, aluminum, aluminum alloys, metal oxides (CoO, FeO, etc.) or titanium oxide.

[0025] As used herein, the term "composite high capacity electrode layer" refers to an electrode layer having both a high capacity material and a traditional anode material (eg, a silicon-graphite layer).

[0026] As used herein, the term "solid high-capacity electrode layer" refers to an electrode layer having a single solid phase high-capacity material, such as sputtered silicon, tin, tin alloys such as Sn-Fe, tin oxide, silicon, silicon alloys such as Si-Co, silicon monoxide, aluminum, aluminum alloys, metal oxides (CoO, FeO, etc.) or titanium oxide.

[0027] Figure 1 1 is a block diagram of an electrochemical cell stack 1000 according to an embodiment. As shown, the electrochemical cell stack 1000 includes electrochemical cells 100a, 100b, 100c (collectively referred to as electrochemical cells 100). However, any number of electrochemical cells may be included in the electrochemical cell stack. In some embodiments, the number of electrochemical cells in each stack 1000 may be in the range of about 2 to about 100, including end values ​​(e.g., about 3, about 4, about 5, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95 or about 100 electrochemical cells, including all ranges and values ​​therebetween).

[0028] The electrochemical cell 100 includes anodes 110a, 110b, 110c (collectively referred to as anodes 110) disposed on anode current collectors 120a, 120b, 120c (collectively referred to as anode current collectors 120), cathodes 130a, 130b, 130c (collectively referred to as cathodes 130) disposed on cathode current collectors 140a, 140b, 140c (collectively referred to as cathode current collectors 140), and separators 150a, 150b, 150c (collectively referred to as separators 150) disposed between the anodes 110 and the cathodes 130. The anode current collector 120 includes anode tabs 122a, 122b, 122c (collectively referred to as anode tabs 122). The cathode current collector 140 includes cathode tabs 142a, 142b, 142c (collectively referred to as cathode tabs 142). Anode voltage measurement point VA a , VA b , VA c The voltages at the anode tab 122a, the anode tab 122b, and the anode tab 122c are measured respectively. Cathode voltage measurement point VC a VC b VC c The voltages at cathode tab 142a, cathode tab 142b, and cathode tab 142c are measured respectively. As shown, each of electrochemical cells 100 is disposed in housing 160. In some embodiments, each of electrochemical cells 100 may be placed in a separate housing.

[0029] The electrochemical cell stack 1000 is equipped to measure the voltage at each anode tab in the anode tab 122 and each cathode tab in the cathode tab 142. Measuring the voltage difference from one anode to another anode or from one cathode to another cathode can help identify problematic cells. For example, in a lithium-ion battery pack containing multiple battery cells connected in series, the battery cell voltages can be monitored individually to ensure that they do not exceed set limits during charging or discharging. Due to differences between battery cells, the battery cells can also be balanced regularly to ensure that the voltage does not deviate significantly, as this will affect overall performance. Balancing can include adding or removing charge from one electrochemical cell in the electrochemical cell 100 to make it consistent with other electrochemical cells 100 in the electrochemical cell stack 1000. In some embodiments, the anode tab 122 and / or the cathode tab 142 can penetrate the housing 160 so that the anode tab 122 and / or the cathode tab 142 can be monitored externally. In some embodiments, anode tab 122 and / or cathode tab 142 may be electrically connected to an external anode tab and / or an external cathode tab (not shown) so that the voltage may be monitored externally.

[0030] Figure 2is a block diagram of an electrochemical cell 200 according to an embodiment. As shown, the electrochemical cell 200 includes an anode 210 disposed on an anode current collector 220, a cathode 230 disposed on a cathode current collector 240, and a separator 250 disposed between the anode 210 and the cathode 230. Anode tabs 222a, 222b, 222c (collectively referred to as anode tabs 222) are coupled to or incorporated into the anode current collector 220, and cathode tabs 242a, 242b, 242c (collectively referred to as cathode tabs 242) are coupled to or incorporated into the anode current collector 240. In some embodiments, the anode 210, the anode current collector 220, the anode tab 222, the cathode 230, the cathode current collector 240, the cathode tab 242, and the separator 250 may be the same as those described above with reference to Figure 1 The described anode 110, anode current collector 120, anode tab 122, cathode 130, cathode current collector 140, cathode tab 142, and separator 150 are the same or substantially similar. Therefore, certain aspects of the anode 210, anode current collector 220, anode tab 222, cathode 230, cathode current collector 240, cathode tab 242, and separator 250 are not described in more detail herein.

[0031] The electrochemical cell 200 includes an anode voltage measurement point VA located on the anode tab 222. a , VA b , VA c (collectively referred to as the anode voltage measurement point VA) and the cathode voltage measurement point VC located on the cathode tab 242 a VC b VC c (collectively referred to as cathode voltage measurement points VC). In other words, the voltage can be measured at multiple locations along the anode 210 and the cathode 230. As described above, the battery cells can be balanced periodically to ensure that the voltage in the stack does not deviate significantly. In battery cells with large area electrodes, there may be voltage gradients within the electrodes, which may affect the voltage measured at any single reference point. The voltage gradient within the electrode may reduce the effectiveness of the balancing and health monitoring algorithms. The voltage gradient within the electrode may also cause a temperature gradient within the electrode and reduce the cycle efficiency. Including multiple anode voltage measurement points VA and multiple cathode voltage measurement points VC for each battery cell 200 in the stack enables the voltage gradient within the electrode to be measured directly, rather than relying on an estimate of the voltage gradient within the electrode from an algorithm, thereby improving the accuracy of the balancing and monitoring methods.

[0032] As shown, the anode current collector 220 includes three anode tabs 222 and three voltage measurement points VA. In some embodiments, the anode current collector 220 may include at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90 or at least about 95 anode tabs 222 and / or voltage measurement points VA. In some embodiments, the anode current collector 220 may include no more than about 100, no more than about 95, no more than about 90, no more than about 85, no more than about 80, no more than about 75, no more than about 70, no more than about 65, no more than about 60, no more than about 55, no more than about 50, no more than about 45, no more than about 40, no more than about 35, no more than about 30, no more than about 25, no more than about 20, no more than about 15, no more than about 10, no more than about 9, no more than about 8, no more than about 7, no more than about 6, no more than about 5, no more than about 4, or no more than about 3 anode tabs 222 and / or voltage measurement points VA. Combinations of the above numbers of anode tabs 222 and voltage measurement points VA are also possible (e.g., at least about 2 and no more than about 100 or at least about 4 and no more than about 30), including all values ​​and ranges therebetween. In some embodiments, the anode current collector 220 may include about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95 or about 100 anode tabs 222 and / or voltage measurement points VA.

[0033] As shown, the cathode current collector 240 includes three cathode tabs 242 and three voltage measurement points VC. In some embodiments, the cathode current collector 240 may include at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, or at least about 95 cathode tabs 242 and / or voltage measurement points VC. In some embodiments, the cathode current collector 240 may include no more than about 100, no more than about 95, no more than about 90, no more than about 85, no more than about 80, no more than about 75, no more than about 70, no more than about 65, no more than about 60, no more than about 55, no more than about 50, no more than about 45, no more than about 40, no more than about 35, no more than about 30, no more than about 25, no more than about 20, no more than about 15, no more than about 10, no more than about 9, no more than about 8, no more than about 7, no more than about 6, no more than about 5, no more than about 4, or no more than about 2 cathode tabs 242 and / or voltage measurement points VC. Combinations of the above numbers of cathode tabs 242 and voltage measurement points VC are also possible (e.g., at least about 2 and no more than about 100 or at least about 4 and no more than about 30), including all values ​​and ranges therebetween. In some embodiments, the cathode current collector 240 may include about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95 or about 100 cathode tabs 242 and / or voltage measurement points VC.

[0034] As shown, the voltage source is provided from above the electrochemical cell 200. In other words, the voltage source can be closer to the anode tab 222a than the anode tab 222c. During discharge, VC c Voltage at >VC b Voltage at >VC a During charging, VC c Voltage at <VC b Voltage at <VC a During charging, VA c Voltage at <VA b Voltage at <VA aDuring the discharge period, VA c Voltage at >VA b Voltage at >VA a The length of the electrochemical cell 200 extends along the y-axis direction, such as Figure 2 The “sensing voltage” may be defined as the difference between VC and VA at a reference point along the length (y-axis) of the electrochemical cell 200. The sense voltage may be measured at various reference points (e.g., VA) along the length (y-axis) of the electrochemical cell 200. a -VC a or VA b -VC b ) to measure the “sense voltage”.

[0035] During or immediately following discharge, the sense voltage is below the average cell voltage. During or immediately following charge, the sense voltage is above the average cell voltage. This effect becomes stronger when any of the following conditions are met: high charge or discharge rates, high surface area electrodes (because the point at which the sense voltage is measured is increasingly distant from the voltage source), low temperature charge or discharge, high resistance cell designs (i.e., low power), and aging batteries with increased internal resistance. Benefits of monitoring the sense voltage include: (1) enhanced health status monitoring, (2) voltage measurements without suspending the balancing function, and (3) early detection of performance issues in the cell (e.g., uneven electrode aging or uneven temperature distribution across the electrode area). Evaluating the voltage difference of active materials on the surface of an electrochemical cell can allow tracking of changes in the active material over time (e.g., increased cell impedance, decreased cell capacity, etc.). Multiple anode ears 222 and cathode ears 242 enable real-time measurement of these changes in active materials. When attempting to detect a faulty cell, measuring the sense voltage from a tab that is also used to balance or power the electrochemical cell 200 is disadvantageous because current flows through the tab and there is active material in close proximity to the tab, which may negatively affect the collected measurements (e.g., cause a voltage shift in the measurements). The voltage shift occurs because the current flowing through the tab material may produce an additional voltage drop and polarize the active material in the cathode. Including multiple anode tabs 222 and cathode tabs 242 addresses this disadvantage because the sense voltage can be measured from the tab through which current does not flow.

[0036] Figure 3An electrochemical cell 300 according to an embodiment is shown. As shown, the electrochemical cell 300 includes an anode current collector 320 having anode tabs 322a, 322b, 322c, 322d, 322e (collectively referred to as anode tabs 322) and a cathode current collector 340 having cathode tabs 342a, 342b, 342c, 342d, 342e (collectively referred to as cathode tabs 342). The electrochemical cell 300 also includes an anode, a cathode, and a separator (not shown). In some embodiments, the anode current collector 320, the cathode tab 322, the cathode current collector 340, and the cathode tab 342 may be the same as described above with reference to Figure 2 The described anode current collector 220, cathode tab 222, cathode current collector 240, and cathode tab 242 are the same or substantially similar. Therefore, certain aspects of anode current collector 320, anode tab 322, cathode current collector 340, and cathode tab 342 are not described in further detail herein.

[0037] For the sake of structural clarity, Figure 3 As shown, the anode current collector 320 has a length L a and width W a As shown, the cathode current collector 340 has a length L c and width W c Length L a and length L c The width W is defined as the distance that the anode current collector 320 extends along the y-axis and the distance that the cathode current collector 340 extends along the y-axis, respectively. a and width W c The distances along the x-axis and the distances along the x-axis of the anode current collector 320 and the cathode current collector 340 are respectively defined. The electrochemical cell 300 includes a proximal end along the y-axis. As shown, the anode tab 322a and the cathode tab 342a are located at the proximal end of the y-axis. The electrochemical cell 300 includes a distal end opposite to the proximal end.

[0038] In some embodiments, L a and / or L c It may be at least about 1 cm, at least about 2 cm, at least about 3 cm, at least about 4 cm, at least about 5 cm, at least about 6 cm, at least about 7 cm, at least about 8 cm, at least about 9 cm, at least about 10 cm, at least about 20 cm, at least about 30 cm, at least about 40 cm, at least about 50 cm, at least about 60 cm, at least about 70 cm, at least about 80 cm, or at least about 90 cm. In some embodiments, L a and / or L cCan be no more than about 1m, no more than about 90cm, no more than about 80cm, no more than about 70cm, no more than about 60cm, no more than about 50cm, no more than about 40cm, no more than about 30cm, no more than about 20cm, no more than about 10cm, no more than about 9cm, no more than about 8cm, no more than about 7cm, no more than about 6cm, no more than about 5cm, no more than about 4cm, no more than about 3cm or no more than about 2cm. The combination of the above lengths is also possible (for example, at least about 1cm and no more than about 1m or at least about 3cm and no more than about 10cm), including all values ​​and ranges therebetween. In some embodiments, L a and / or L c It can be about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 20 cm, about 30 cm, about 40 cm, about 50 cm, about 60 cm, about 70 cm, about 80 cm, about 90 cm or about 1 m.

[0039] In some embodiments, W a and / or W c It can be at least about 5 mm, at least about 6 mm, at least about 7 mm, at least about 8 mm, at least about 9 mm, at least about 1 cm, at least about 2 cm, at least about 3 cm, at least about 4 cm, at least about 5 cm, at least about 6 cm, at least about 7 cm, at least about 8 cm, at least about 9 cm, at least about 10 cm, at least about 20 cm, at least about 30 cm, or at least about 40 cm. In some embodiments, W a and / or W c Can be no more than about 50cm, no more than about 40cm, no more than about 30cm, no more than about 20cm, no more than about 10cm, no more than about 9cm, no more than about 8cm, no more than about 7cm, no more than about 6cm, no more than about 5cm, no more than about 4cm, no more than about 3cm, no more than about 2cm, no more than about 1cm, no more than about 9mm, no more than about 8mm, no more than about 7mm or no more than about 6mm. The combination of the above widths is also possible (for example, at least about 5mm and no more than about 50cm or at least about 2cm and no more than about 10cm), including all values ​​and ranges therebetween. In some embodiments, W a and / or W c It can be about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 20 cm, about 30 cm, about 40 cm or about 50 cm.

[0040] As shown, the anode current collector 320 includes 5 anode tabs 322. In some embodiments, the anode current collector 320 may include at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, or at least about 95 anode tabs 322. In some embodiments, the anode current collector 320 may include no more than about 100, no more than about 95, no more than about 90, no more than about 85, no more than about 80, no more than about 75, no more than about 70, no more than about 65, no more than about 60, no more than about 55, no more than about 50, no more than about 45, no more than about 40, no more than about 35, no more than about 30, no more than about 25, no more than about 20, no more than about 15, no more than about 10, no more than about 9, no more than about 8, no more than about 7, no more than about 6, no more than about 5, no more than about 4, or no more than about 3 anode tabs 322. Combinations of the above numbers of anode tabs 322 are also possible (e.g., at least about 2 and no more than about 100 or at least about 5 and no more than about 50), including all values ​​and ranges therebetween. In some embodiments, the anode current collector 320 may include about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95 or about 100 anode tabs 322.

[0041] As shown, the cathode current collector 340 includes 5 cathode tabs 342. In some embodiments, the cathode current collector 340 may include at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, at least about 75, at least about 80, at least about 85, at least about 90, or at least about 95 cathode tabs 342. In some embodiments, the cathode current collector 340 may include no more than about 100, no more than about 95, no more than about 90, no more than about 85, no more than about 80, no more than about 75, no more than about 70, no more than about 65, no more than about 60, no more than about 55, no more than about 50, no more than about 45, no more than about 40, no more than about 35, no more than about 30, no more than about 25, no more than about 20, no more than about 15, no more than about 10, no more than about 9, no more than about 8, no more than about 7, no more than about 6, no more than about 5, no more than about 4, or no more than about 3 cathode tabs 342. Combinations of the above numbers of cathode tabs 342 are also possible (e.g., at least about 2 and no more than about 100 or at least about 5 and no more than about 50), including all values ​​and ranges therebetween. In some embodiments, the cathode current collector 340 can include about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, or about 100 cathode tabs 342.

[0042] As shown, the cathode current collector 340 includes a c A cathode tab 342a positioned and extending outwardly (eg, in the positive y-direction) from the proximal end of the electrochemical cell 300 and along the L c Four cathode tabs 342b, 342c, 342d, 342e are positioned and extend outwardly (eg, in the negative x-direction) from a first horizontal side of the electrochemical cell 300. In some embodiments, the cathode current collector 340 may include a cathode electrode 342b, 342c, 342d, 342e extending outwardly (eg, in the negative x-direction) from a first horizontal side of the electrochemical cell 300. c and a plurality of cathode tabs 342 extending outward. As shown in the figure, the anode current collector 320 includes a plurality of cathode tabs 342 extending outward. a An anode tab 322a positioned and extending outwardly (eg, in the positive y-direction) from the proximal end of the electrochemical cell 300 and along the L aThe anode current collector 320 may include four anode tabs 322b, 322c, 322d, 322e positioned and extending outwardly (eg, in the positive x-direction) from the second horizontal side of the electrochemical cell 300. a A plurality of anode tabs 322 extend outwardly from the proximal end of the electrochemical cell 300 .

[0043] In some embodiments, the distance between each cathode pole ear in cathode pole ear 342a, 342b, 342c, 342d, 342e and the distance between each cathode pole ear in anode pole ear 322a, 322b, 322c, 322d, 322e can be at least about 0.5cm, at least about 1cm, at least about 1.5cm, at least about 2cm, at least about 2.5cm or at least about 3cm. In some embodiments, the distance between each cathode pole ear in cathode pole ear 342 and the distance between each anode pole ear in anode pole ear 322 can be no more than about 5cm, no more than about 4.5cm, no more than about 4cm, no more than about 3.5cm, no more than about 3cm, no more than about 2.5cm, no more than about 2cm, no more than about 1.5cm, no more than about 1cm. Combinations of the above distances are also possible, including all values ​​and ranges therebetween.

[0044] In some embodiments, the cathode tabs 342 (e.g., cathode tabs 342b, 342c, 342d, 342e) extending from the same side of the cathode current collector 340 may be evenly spaced apart from each other. In some embodiments, the cathode tabs 342 extending from the same side of the cathode current collector 340 may be unevenly spaced apart or their spacing may be variable. In some embodiments, the anode tabs 322 (e.g., anode tabs 322b, 322c, 322d, 322e) extending from the same side of the anode current collector 320 may be evenly spaced apart from each other. In some embodiments, the anode tabs 322 extending from the same side of the anode current collector 320 may be unevenly spaced apart or their spacing may be variable.

[0045] In some embodiments, anode tabs 322b, 322c, 322d, 322e can be aligned or substantially aligned (i.e., along the y-axis) with cathode tabs 342b, 342c, 342d, 342e, respectively. Any number of anode tabs 322 can be aligned with any number of cathode tabs 342. In other words, any number of anode tabs 322 can be located at the same or substantially similar position along the L axis as any number of cathode tabs 342. a or L cIn some embodiments, any of anode tabs 322 may be within about 10%, within about 9%, within about 8%, within about 7%, within about 6%, within about 5%, within about 4%, within about 3%, within about 2%, or within about 1% of the alignment along the y-axis with any of cathode tabs 342.

[0046] The anode tab 322 may extend along the length L of the anode current collector 320. a A plurality of locations or reference points are provided so that anode voltage measurements can be made at a plurality of locations or reference points of the anode current collector 320. The cathode tab 342 may be located along the length L of the cathode current collector 320. c Providing multiple locations or reference points enables cathode voltage measurements to be made at multiple locations of cathode current collector 340. A sensed voltage (e.g., the difference between the cathode voltage and the anode voltage) can then be calculated at each of the multiple reference points. In some embodiments, electrochemical cell 300 can be formed along the width W of anode current collector 320. a Anode tabs 322 are included at multiple locations or reference points. In some embodiments, electrochemical cell 300 may be formed along the width W of cathode current collector 340. c A cathode tab 342 is included at a plurality of locations or reference points. a and W a Multiple reference points for measuring both anode and / or cathode voltages enable detection of intra-electrode gradients along both the length (y-direction) of the electrochemical cell 300 and the width (x-direction) of the electrochemical cell 300. In some embodiments, the anode tab 322a and cathode tab 342a can be used to perform a balancing function while monitoring the cathode voltage and the anode voltage, thereby enabling monitoring of the electrochemical cell 300 without the need to suspend the balancing function.

[0047] Figure 4An electrochemical cell 400 according to an embodiment is shown. As shown, the electrochemical cell 400 includes an anode current collector 420 having anode tabs 422a, 422b, 422c, 422d (collectively referred to as anode tabs 422) and a cathode current collector 440 having cathode tabs 442a, 442b, 442c, 442d, 442e (collectively referred to as cathode tabs 442). The electrochemical cell 400 also includes an anode, a cathode, and a separator (not shown). The electrochemical cell 400 also includes a shell or housing 460 having external anode tabs 423a, 423b, 423c, 423d (collectively referred to as external anode tabs 423) and external cathode tabs 443a, 443b, 443c, 444d (collectively referred to as external cathode tabs 443) attached thereto. In some embodiments, the anode current collector 420, the cathode tab 422, the cathode current collector 440, and the cathode tab 442 may be the same as those described above. Figure 3 The described anode current collector 320, cathode tab 322, cathode current collector 340, and cathode tab 342 are the same or substantially similar. Therefore, certain aspects of anode current collector 420, anode tab 422, cathode current collector 440, and cathode tab 442 are not described in further detail herein.

[0048] Anode tab 422 is electrically coupled to external anode tab 423. Cathode tab 442 is electrically coupled to external cathode tab 443. In some embodiments, external anode tab 423 and external cathode tab 443 may be integrated into housing 460. In other words, external anode tab 423 and external cathode tab 443 may be part of the same piece of material as housing 460. External anode tab 423 and external cathode tab 443 allow for connection of a voltage source or voltage measurement device at various points along the anode and / or cathode.

[0049] Figure 5 is a schematic flow chart of a method 500 for monitoring the health of an electrochemical cell. Although described with respect to an electrochemical cell 200 including an anode tab 222, a cathode tab 242, an anode current collector 220 and a cathode current collector 240, an anode material 210, a cathode material 240, and a separator 250, the method 500 is equally applicable to any electrochemical cell including any anode tab, cathode tab, anode current collector, cathode current collector, anode material, cathode material, separator, and / or any other component described herein. All such variations should be considered within the scope of the present disclosure.

[0050] At step 502, the method 500 optionally includes providing an electrochemical cell 200 including an anode material 210 coupled to an anode current collector 220 having a plurality of anode tabs 222; a cathode material 230 coupled to a cathode current collector 240 having a plurality of tabs 242; and a separator 250 disposed between the anode material 210 and the cathode material 230. At step 504, a first anode voltage may be measured at a first anode tab from the plurality of anode tabs 222, and a second anode voltage may be measured at a second anode tab from the plurality of anode tabs 222. In some embodiments, the first anode tab and the second anode tab from the anode tabs 222 may be located on the same horizontal side of the electrochemical cell 200, the first anode tab being closer to a proximal end of the electrochemical cell 200 than the second anode tab. At step 506, a first cathode voltage may be measured at a first cathode tab from the plurality of cathode tabs 242, and a second cathode voltage may be measured at a second cathode tab from the plurality of cathode tabs 242. In some embodiments, the first cathode tab and the second cathode tab from the cathode tabs 242 may be located on the same horizontal side of the electrochemical cell 200, with the first cathode tab being closer to the proximal end of the electrochemical cell 200 than the second cathode tab.

[0051] At step 508, the method 500 includes calculating a first sensing voltage, which is the difference between the first cathode voltage and the first anode voltage. At optional step 510, a second sensing voltage may be calculated, which is the difference between the second cathode voltage and the second anode voltage. At step 512, the method 500 may optionally include calculating the difference between the first sensing voltage and the second sensing voltage, so as to enable detection and / or quantification of the intra-electrode gradient along the length of the electrochemical cell 200 (e.g., in the y direction). In some embodiments, the method 500 may optionally include calculating a third sensing voltage, which is the difference between the third cathode voltage measured at the third cathode tab located on the proximal end of the electrochemical cell 200 and the third anode voltage measured at the third anode tab on the proximal end of the electrochemical cell 200. The third sensing voltage enables detection and / or quantification of the intra-electrode gradient along the width of the electrochemical cell 200 (in the x direction). In some embodiments, the method 500 may include balancing the electrochemical cell 200 via the third anode tab and the third cathode tab. For example, charge can be added to or removed from the electrochemical cell 200 via the third anode tab and / or the third cathode tab. In some embodiments, any of the anode tabs 222 and any of the cathode tabs 244 can be used to balance the electrochemical cell 200. In some embodiments, the electrochemical cell 200 can be placed in a housing. In some embodiments, the method 500 can include measuring the anode voltage and the cathode voltage via a plurality of external anode tabs and a plurality of external cathode tabs, respectively, so that the anode voltage and the cathode voltage are measured outside the housing.

[0052] Various concepts can be implemented as one or more methods, wherein at least one example has been provided. The actions performed as part of the method can be ordered in any suitable manner. Therefore, such an embodiment can be constructed in which the actions are performed in an order different from the order shown, which may include performing some actions simultaneously, even if the action is shown as a continuous action in the illustrative embodiment. In other words, it should be understood that such features are not necessarily limited to a specific execution order, but any number of threads, processes, services, servers and / or etc. that can be performed in series, asynchronously, concurrently, in parallel, simultaneously, synchronously and / or in a manner consistent with the present disclosure. Therefore, some of these features may contradict each other because these features cannot exist in a single embodiment at the same time. Similarly, some features are applicable to one aspect of the innovation and are not applicable to other aspects.

[0053] In addition, the present disclosure may include other innovations not currently described. Applicants reserve all rights to such innovations, including the right to embody such innovations, submit additional applications, continuations, partial continuations, divisions, and / or the like. Therefore, it should be understood that the advantages, embodiments, examples, functions, features, logic, operations, organizations, structures, topologies, and / or other aspects of the present disclosure should not be considered as limitations on the present disclosure as defined by the embodiments or limitations on the equivalents of the embodiments. Depending on the specific expectations and / or characteristics of individual and / or enterprise users, database configurations and / or relational models, data types, data transmissions, and / or network architectures, grammatical structures, and / or the like, the various embodiments of the technology disclosed herein can be implemented in a manner that realizes a large amount of flexibility and customization as described herein.

[0054] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0055] As used herein, in particular embodiments, the term "about" or "approximately" when preceding a numerical value represents a range of plus or minus 10% of the value. Where a range of values ​​is provided, it is understood that, unless the context clearly indicates otherwise, each intermediate value (to one-tenth of the unit of the lower limit) between the upper and lower limits of the range and any other stated values ​​or intermediate values ​​within the range are included in the present disclosure. The upper and lower limits of these smaller ranges can be independently included in smaller ranges and are also included in the present disclosure, subject to any specific exclusion limits within the range. Where the stated range includes one or two of the limits, ranges other than any one or two of the included limits are also included in the present disclosure.

[0056] The phrase "and / or" used herein in the specification and examples should be understood to mean "either or both" of the elements so combined, i.e., elements that exist jointly in some cases and separately in other cases. Multiple elements listed with "and / or" should be understood in the same way, i.e., "one or more" of the elements so combined. In addition to the elements specifically identified by the "and / or" clause, other elements may optionally be present, whether related or unrelated to those specifically identified. Therefore, as a non-limiting example, when used in conjunction with open language such as "including", reference to "A and / or B" may refer to only A (optionally including elements other than B) in one embodiment; in another embodiment, only B (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); etc.

[0057] As used herein in the specification and in the embodiments, "or" should be understood to have the same meaning as the meaning of "and / or" as defined above. For example, when the items in the list are separated, "or" or "and / or" should be interpreted as inclusive, that is, including at least one element in multiple elements or element lists, but also including more than one element, and optionally other unlisted items. Only explicitly point out the opposite terms such as "only one of ..." or "exactly one of ..." or when used in the embodiments, "consisting of ..." will refer to including exactly one element in many elements or element lists. In general, when there are exclusive terms before, such as "any one", "one of ...", "only one of ..." or "exactly one of ...", the term "or" as used herein should only be interpreted as indicating exclusive alternatives (that is, "one or other one, not two"). When used in the embodiments, "essentially consisting of ..." should have its ordinary meaning as used in the field of patent law.

[0058] As used herein in the specification and in the examples, the phrase "at least one" of a list of one or more elements is understood to mean at least one element selected from any one or more elements in the list of elements, but does not necessarily include at least one of each element specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition also allows for the optional presence of elements in addition to the elements specifically identified in the list of elements to which the phrase "at least one" refers, whether related to or unrelated to the specifically identified elements. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") can refer to at least one in one embodiment, optionally including more than one A, without B (and optionally including elements other than B); in another embodiment, refers to at least one, optionally including more than one B, without A (and optionally including elements other than A); in yet another embodiment, refers to at least one, optionally including more than one A, and at least one, optionally including more than one B (and optionally including other elements); etc.

[0059] In the examples and in the above description, all transitional phrases such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "comprising", etc. should be understood as open-ended, i.e., meaning including but not limited to. As described in Section 2111.03 of the Manual of Patent Examining Procedures of the United States Patent Office, only the transitional phrases "consisting of" and "consisting essentially of" should be closed or semi-closed transitional phrases, respectively.

[0060] Although specific embodiments of the present disclosure have been summarized above, many substitutions, modifications and variations are apparent to those skilled in the art. Therefore, the embodiments set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of the present disclosure. Where the above methods and steps indicate specific events occurring in a particular order, those of ordinary skill in the art who benefit from the present disclosure will recognize that the order of specific steps may be modified, and such modifications are variations according to the present invention. In addition, as described above, certain steps in the steps may be performed simultaneously in a parallel process, as well as sequentially, where possible. Embodiments have been specifically shown and described, but it will be appreciated that various changes in form and detail may be made.

Claims

1. A method of operating an electrochemical cell included in an electrochemical cell stack having a plurality of electrochemical cells, wherein each of the electrochemical cells in the electrochemical cell stack includes an anode material coupled to an anode current collector having a plurality of anode tabs, a cathode material coupled to a cathode current collector having a plurality of cathode tabs, and a separator disposed between the anode material and the cathode material, the method comprising: measuring an anode voltage difference between a first anode tab from the plurality of anode tabs and a second anode tab from the plurality of anode tabs of the electrochemical cell; measuring a cathode voltage difference between a first cathode tab from the plurality of cathode tabs and a second cathode tab from the plurality of cathode tabs of the electrochemical cell; as well as The electrochemical cell is balanced relative to other electrochemical cells included in the electrochemical cell stack based at least on the values ​​of the anode voltage difference and the cathode voltage difference. 2 . The method of claim 1 , wherein the first cathode tab and the first anode tab are each located at a proximal end of the electrochemical cell. 3 . The method of claim 2 , wherein a distance between the first anode tab and the second anode tab is within about 5% of a distance between the first cathode tab and the second cathode tab.

4. The method of claim 2, wherein the second cathode tab extends outwardly from a first horizontal side of the electrochemical cell and the second anode tab extends outwardly from a second horizontal side of the electrochemical cell, the second horizontal side being opposite the first horizontal side.

5. The method of claim 1, wherein the cathode current collector and the anode current collector each have a length of at least about 5 cm.

6. The method of claim 1, wherein the electrochemical cell is disposed in a housing comprising a plurality of external anode tabs and a plurality of external cathode tabs such that the anode voltage difference and the cathode voltage difference are measured from outside the housing.

7. A method of monitoring the health of an electrochemical cell, the electrochemical cell comprising an anode material coupled to an anode current collector having a plurality of anode tabs, a cathode material coupled to a cathode current collector having a plurality of cathode tabs, and a separator disposed between the anode material and the cathode material, the method comprising: measuring a first anode voltage at a first anode tab from the plurality of anode tabs and measuring a second anode voltage at a second anode tab from the plurality of anode tabs; measuring a first cathode voltage at a first cathode tab from the plurality of cathode tabs and measuring a second cathode voltage at a second cathode tab from the plurality of cathode tabs; A first sensing voltage is calculated, the first sensing voltage being a difference between the first cathode voltage and the first anode voltage.

8. The method according to claim 7, further comprising: A second sensing voltage is calculated, the second sensing voltage being a difference between the second cathode voltage and the second anode voltage.

9. The method according to claim 8, further comprising: A difference between the first sensing voltage and the second sensing voltage is calculated.

10. The method of claim 7, wherein the first cathode tab and the first anode tab extend outwardly from a proximal end of the electrochemical cell.

11. The method of claim 10, wherein a distance between the first anode tab and the second anode tab is within about 5% of a distance between the first cathode tab and the second cathode tab.

12. The method of claim 10, wherein the second cathode tab extends outwardly from a first horizontal side of the electrochemical cell and the second anode tab extends outwardly from a second horizontal side of the electrochemical cell, the second horizontal side opposite the first horizontal side.

13. The method of claim 7, wherein the cathode current collector and the anode current collector each have a length of at least about 5 cm.

14. The method of claim 7, wherein the cathode current collector and the anode current collector each have a width of at least about 5 mm.

15. The method of claim 7, wherein the electrochemical cell is disposed in a housing comprising a plurality of external anode and a plurality of external cathode tabs such that the first anode voltage, the second anode voltage, the first cathode voltage, and the second cathode voltage are measured from outside the housing.

16. An electrochemical cell comprising: an anode material coupled to an anode current collector; a cathode material coupled to a cathode current collector; a separator disposed between the anode material and the cathode material; a plurality of anode tabs electrically connected to the anode current collector such that a first anode voltage can be measured at a first anode tab from the plurality of anode tabs and a second anode voltage can be measured at a second anode tab from the plurality of anode tabs; as well as A plurality of cathode tabs are electrically connected to the cathode current collector such that a first cathode voltage can be measured at a first cathode tab from the plurality of cathode tabs and a second cathode voltage can be measured at a second cathode tab from the plurality of cathode tabs.

17. The electrochemical cell of claim 16, wherein the first cathode tab and the first anode tab extend outwardly from a proximal end of the electrochemical cell.

18. The electrochemical cell of claim 17, wherein: The plurality of cathode tabs except the first cathode tab extend outwardly from a first horizontal side of the electrochemical cell, and the plurality of anode tabs except the first anode tab extend outwardly from a second horizontal side of the electrochemical cell, the second horizontal side opposite the first horizontal side.

19. The electrochemical cell of claim 18, wherein the distance between the first anode tab and the second anode tab is within about 5% of the distance between the first cathode tab and the second cathode tab.

20. The electrochemical cell of claim 16, wherein the distance between each of the anode tabs is in a range of about 1 cm to about 3 cm, and the distance between each of the cathode tabs is in a range of about 1 cm to about 3 cm.

21. The electrochemical cell of claim 16, wherein the cathode current collector and the anode current collector each have a length of at least about 5 cm.

22. The electrochemical cell of claim 16, wherein the cathode current collector and the anode current collector each have a width of at least about 5 mm.

23. An electrochemical cell according to claim 17, wherein the electrochemical cell is placed in a shell, the shell comprising a plurality of external anode tabs and a plurality of external cathode tabs, so that the first anode voltage, the second anode voltage, the first cathode voltage and the second cathode voltage can be measured from outside the shell.

24. The electrochemical cell of claim 16, wherein a first voltage gradient is measurable along the width of the electrochemical cell and a second voltage gradient is measurable along the length of the electrochemical cell.

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