Electrochemical cells connected in series in single pouch and methods of making the same

Abstract

To provide electrochemical cells connected in series in a single pouch.SOLUTION: An multicell is provided which includes a plurality of electrochemical cells. Each of the electrochemical cells includes: an anode disposed on an anode current collector including an anode tab; a cathode disposed on a cathode current collector including a cathode tab; and a separator disposed between the anode and the cathode. The cathode tab of a first electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a second electrochemical cell of the plurality of electrochemical cells at a first connection point. The cathode tab of a second electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a third electrochemical cell of the plurality of electrochemical cells at a second connection point. The electrochemical cells are disposed in a single pouch.SELECTED DRAWING: Figure 3C

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 62 / 938,107, entitled "Serially Connected Electrochemical Cells in a Single Pouch and Methods of Making Same," filed November 20, 2019, and U.S. Provisional Application No. 63 / 009,085, entitled "Serially Connected Electrochemical Cells in a Single Pouch and Methods of Making Same," filed April 13, 2020, the disclosures of each of which are incorporated herein by reference in their entireties.

[0002] FIELD OF THE INVENTION

[0002] Embodiments described herein relate to series-connected electrochemical cells in a single pouch and methods for making the same. [Background technology]

[0003]

[0003] Embodiments described herein relate to electrochemical cells connected in series in a single pouch and methods for making the same. Electrochemical cells can often be connected in series to increase the total voltage of a system while maintaining a constant system capacity. For example, connecting two 9-volt batteries in series can create a system with an 18-volt voltage drop but the same capacity as a single 9-volt battery. Additionally, a battery management system (BMS) can be employed to control the operation of a single electrochemical cell or a system of electrochemical cells. In some cases, the BMS can monitor the state of charge of the electrochemical cells, protect the electrochemical cells from operating outside their safe operating area, balance individual cell voltages, or monitor and report performance statistics of the cells as a whole. Summary of the Invention

[0004]

[0004] Embodiments described herein relate to systems and stacks of multiple electrochemical cells. The electrochemical cell stack includes a plurality of electrochemical cells connected in series in a single pouch. Each electrochemical cell of the plurality of electrochemical cells includes an anode disposed on an anode current collector, a cathode disposed on a cathode current collector, and a separator disposed between the anode and the cathode. The anode current collector includes an anode tab, and the cathode current collector includes a cathode tab. In some embodiments, the anode tab can be a welded tab. In some embodiments, the cathode tab can be a welded tab. In some embodiments, a first electrochemical cell of the plurality of electrochemical cells can be connected in series to a second electrochemical cell of the plurality of electrochemical cells by electronically coupling the cathode tab of the first electrochemical cell to the anode tab of the second electrochemical cell. In some embodiments, a second electrochemical cell can be connected in series to a third electrochemical cell by electronically coupling the cathode tab of the second electrochemical cell to the anode tab of the third electrochemical cell. In some embodiments, the third electrochemical cell can be connected in series to a fourth electrochemical cell by electronically coupling the cathode tab of the third electrochemical cell to the anode tab of the fourth electrochemical cell. In some embodiments, the anode and cathode tabs of each of the plurality of electrochemical cells can be trimmed so that the interconnected tabs are aligned with each other and do not touch each other. In some embodiments, each of the plurality of electrochemical cells can be disposed within a single pouch.

[0005] In some embodiments, each electrical connection between the cathode tab and the anode tab, as well as the anode tab of the first electrochemical cell and the cathode tab of the fourth electrochemical cell, may also be connected to an extension tab that protrudes outside the single pouch. In some embodiments, the total voltage drop across the multiple electrochemical cells may be custom selected by connecting a first connector to the first extension tab and a second connector to the second extension tab. In some embodiments, the electrochemical cell system may include multiple electrochemical cell stacks, each including multiple electrochemical cells disposed within a single pouch. In some embodiments, the electrochemical cell system may include a BMS configured to control charge and discharge within specified limits. In some embodiments, each pouch of the electrochemical cell system may include a vent tab configured to allow trapped gas to escape during cell formation. [Brief explanation of the drawings]

[0006] [Figure 1] 1 illustrates a multi-cell according to one embodiment. [Figure 2A]

[0007] 1 illustrates an individual electrochemical cell according to one embodiment. [Figure 2B] 1 illustrates an individual electrochemical cell according to one embodiment. [Figure 3A]

[0008] 1 illustrates multiple electrochemical cells connected in series to form a multi-cell and disposed within a single pouch, according to one embodiment. [Figure 3B]

[0008] Figure 1 shows multiple electrochemical cells connected in series to form a multi-cell and disposed within a single pouch, according to one embodiment. [Figure 3C]

[0008] Figure 1 shows multiple electrochemical cells connected in series to form a multi-cell and disposed within a single pouch, according to one embodiment. [Figure 3D]

[0008] Figure 1 shows multiple electrochemical cells connected in series to form a multi-cell and disposed within a single pouch, according to one embodiment. [Figure 3E]

[0008] Figure 1 shows multiple electrochemical cells connected in series to form a multi-cell and disposed within a single pouch, according to one embodiment. [Figure 4A]

[0009] 1 illustrates a multi-cell system according to one embodiment. [Figure 4B] 1 illustrates a multi-cell system according to one embodiment. [Figure 5A]

[0010] 1 illustrates a multi-cell system according to one embodiment. [Figure 5B] 1 illustrates a multi-cell system according to one embodiment. [Figure 6A]

[0011] 1 illustrates a multi-cell system according to one embodiment. [Figure 6B] 1 illustrates a multi-cell system according to one embodiment. [Figure 7A]

[0012] 1 illustrates a multi-cell system according to one embodiment. [Figure 7B] 1 illustrates a multi-cell system according to one embodiment. [Figure 8A]

[0013] 1 illustrates multiple multi-cells connected to a single BMS according to one embodiment. [Figure 8B] 1 illustrates multiple multi-cells connected to a single BMS according to one embodiment. [Figure 8C] 1 illustrates multiple multi-cells connected to a single BMS according to one embodiment. [Figure 9A]

[0014] 1 illustrates multiple multi-cells with venting tabs connected to a single BMS, according to one embodiment. [Figure 9B] 1 illustrates multiple multi-cells with venting tabs connected to a single BMS, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007]

[0015]

[0002] Embodiments described herein relate to electrochemical cells connected in series in a single pouch and methods for making the same. Advantages of having multiple cells connected in series in a single pouch include reducing the amount of packaging material required for a given system size. This can translate into reduced costs and overall system mass. For example, a system with multiple cells connected in series in a single pouch may have less aluminized sealing film and fewer feed-through tabs.

[0008]

[0016] An additional advantage of connecting multiple electrochemical cells in series in a single pouch is the variability of voltage and / or capacity. For example, by organizing a series of tabs to contact multiple electrochemical cells at various points in the series, an external circuit can be attached to any pair of tabs to provide a wide range of voltages. For example, four lithium iron phosphate (3.2 V) electrochemical cells can be connected in series in a circuit within a single pouch. A first tab can be placed to contact the circuit at a point upstream of the first electrochemical cell, a second tab can be placed at a point on the circuit between the first and second electrochemical cells, a third tab can be placed at a point on the circuit between the second and third electrochemical cells, a fourth tab can be placed at a point on the circuit between the third and fourth electrochemical cells, and a fifth tab can be placed at a point on the circuit downstream of the fourth electrochemical cell. An external circuit can then be connected to any pair of tabs depending on the desired voltage. For example, an external circuit may be attached to the first and third tabs to create a circuit with a voltage of 6.4 V. An external circuit may be attached to the first and fourth tabs to create a circuit with a voltage of 9.6 V. An external circuit may be attached to the first and fifth tabs to create a circuit with a voltage of 12.8 V. Any other combination of tab connections to the external circuit is also possible.

[0009]

[0017] In some embodiments, a stack of multiple electrochemical cells connected in series in a single pouch (also referred to herein as a "multi-cell") can be connected in series or parallel to one or more additional multi-cells. For example, several multi-cells can be connected in parallel in a multi-cell system to increase the electrochemical capacity of the multi-cell system compared to a single multi-cell while maintaining the same voltage variability. In some embodiments, several multi-cells can be connected in series in a multi-cell system to provide higher voltage capability and more voltage variability compared to a single multi-cell. In some embodiments, multiple multi-cells can be connected in both series and parallel to increase the electrochemical capacity and provide higher voltage capability / variability compared to a single multi-cell.

[0010]

[0018] In some embodiments, the electrochemical cells described herein can include a semi-solid cathode and / or a semi-solid anode. In some embodiments, the semi-solid electrodes described herein can be binderless and / or use less binder than typically used in conventional battery manufacturing. The semi-solid electrodes described herein can be formulated as a slurry such that the electrolyte is included in the slurry formulation. This is in contrast to conventional electrodes, such as calendered electrodes, where the electrolyte is generally added to the electrochemical cell once the electrochemical cell is disposed in a container, such as a pouch or can.

[0011]

[0019] In some embodiments, the electrode materials described herein can be flowable semi-solid or condensate compositions. In some embodiments, a flowable semi-solid electrode can include a suspension of electrochemically active material (anode or cathode particles or particulates) and, optionally, an electronically conductive material (e.g., carbon) in a non-aqueous electrolyte. In some embodiments, the active electrode particles and conductive particles can be co-suspended in the electrolyte to produce a semi-solid electrode. In some embodiments, the electrode materials described herein can include conventional electrode materials (e.g., including lithium metal).

[0012]

[0020] Systems and methods for charging and discharging multiple batteries connected in series are described in U.S. Pat. No. 10,153,651 (the "'651 patent"), entitled "Systems and Methods for Series Battery Charging," the disclosure of which is incorporated herein by reference in its entirety. Electrochemical cell chemistry and anode / cathode composition are described in U.S. Pat. No. 9,437,864 (the "'864 patent"), entitled "Asymmetric Battery Having a Semi-Solid Cathode and High Energy Density Anode," the disclosure of which is incorporated herein by reference in its entirety.

[0013]

[0021] In some embodiments, the electrodes and / or electrochemical cells described herein can include a solid-state electrolyte. In some embodiments, the anodes described herein can include a solid-state electrolyte. In some embodiments, the cathodes described herein can include a solid-state electrolyte. In some embodiments, the electrochemical cells described herein can include a solid-state electrolyte in both the anode and the cathode. In some embodiments, the electrochemical cells described herein can include a unit cell structure with a solid-state electrolyte. In some embodiments, the solid-state electrolyte material can be a powder that is mixed with a binder and then processed (e.g., extruded, cast, wet-cast, blown, etc.) to form a sheet of solid-state electrolyte material. In some embodiments, the solid-state electrolyte material can be a garnet structure, a perovskite structure, a phosphate-based lithium superionic conductor (LISICON) structure, a La 0.51 Li 0.34 TiO 2.94 ,Li 1.3 Al 0.3 Ti 1.7 (PO4)3,Li 1.4 Al 0.4 Ti 1.6 (PO4)3,Li7La3Zr2O 12 ,Li 6.6 6La3Zr 1.6 Ta 0.4 O 12,9 (LLZO),50Li4SiO4·50Li3BO3,Li 2.9 PO 3.3 N 0.46 (Lithium phosphate oxynitride, LiPON), Li 3.6 Si 0.6 P 0.4 Oxide-based solid electrolyte materials including glass structures such as O4, Li3BN2, Li3BO3-Li2SO4, Li3BO3-Li2SO4-Li2CO3 (LIBSCO, pseudo-ternary system), and / or thio-LISICON structure, glassy structure, and Li 1.07 Al 0.69 Ti 1.46 (PO4)3,Li 1.5 Al 0.5 Ge 1.5(PO4)3,Li 10 GeP2S 12 (LGPS),30Li2S・26B2S3・44LiI,63Li2S・36SiS2・1Li3PO4,57Li2S・38SiS2・5Li4SiO4,70Li2S・30P2S5,50Li2S・50GeS2,Li7P3S 11 ,Li 3.25 P 0.95 S4,Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Sulfide-containing solid electrolyte materials including glass-ceramic structures such as LiBH4-LiI, LiBH4-LiNH2, LiBH4-P2S5, Li(CB9H 10 )-LiI such as Li(CB X H X+1 The solid electrolyte may be a closo-based complex hydride solid electrolyte, such as )-LiI, and / or one or more of the lithium electrolyte salts bis(trifluoromethane)sulfonamide (TFSI), bis(pentafluoroethanesulfonyl)imide (BETI), bis(fluorosulfonyl)imide, lithium borate oxalatophosphine oxide (LiBOP), lithium bis(fluorosulfonyl)imide, amidoborohydride, LiBF, LiPF, LIF, or a combination thereof. In some embodiments, the electrodes described herein may comprise from about 40% to about 90% by weight of the solid electrolyte. Examples of electrochemical cells and electrodes comprising a solid electrolyte are described in U.S. Pat. No. 10,734,672, entitled "Electrochemical Cells Including Selectively Permeable Membranes, Systems and Methods of Manufacturing the Same," filed January 8, 2019 (the "'672 Patent"), the disclosure of which is incorporated herein by reference in its entirety.

[0014]

[0022] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, the term "a member" is intended to mean a single member or combination of members, and "a material" is intended to mean one or more materials or combinations thereof.

[0015]

[0023] As used herein, the term "set" may refer to multiple features or a single feature that comprises multiple parts. For example, when referring to a set of battery modules, the set of modules may be considered to be one module with individual parts (e.g., cell fixtures, wires, connectors, etc.), or the set of modules may be considered to be multiple modules. Similarly, a monolithically constructed item may include a set of modules. Such a set of modules may, for example, include multiple parts that are discontinuous with one another. A set of modules may also be fabricated from multiple items that are produced separately and later joined (e.g., via welding, adhesive, or any suitable method).

[0016]

[0024] As used herein, the terms "about," "approximately," and "approximately" when used in connection with a numerical value are intended to convey that the value so defined is nominally its stated value. Stated differently, the terms "about," "approximately," and "approximately" when used in connection with a numerical value generally include the stated value, plus or minus a given tolerance. For example, in some cases, a suitable tolerance may be plus or minus 10% of the stated value. Thus, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, and about 1000 would include 900 to 1100. In other cases, a suitable tolerance may be plus or minus an acceptable percentage of the last significant figure of the stated value. For example, a suitable tolerance may be plus or minus 10% of the last significant figure. Thus, about 10.1 would include 10.09 and 10.11, and about 25 would include 24.5 and 25.5. Such variances may arise due to manufacturing tolerances or other practical considerations (such as tolerances associated with measuring equipment, allowable human error, or the like).

[0017]

[0025] FIG. 1 illustrates a multi-cell 1000 according to one embodiment. As shown, the multi-cell 1000 includes electrochemical cells 100a, 100b, and 100c (collectively referred to as electrochemical cells 100) and connection points 105a, 105b, 105c, and 105d (collectively referred to as connection points 105). As shown, the electrochemical cells 100 are connected in series in a single circuit in a pouch 160. In some embodiments, the multi-cell 1000 can include extension tabs 146a, 146b, 146c, and 146d (collectively referred to as extension tabs 146) that extend from connection points 105 inside the pouch 160 to the outside of the pouch 160. An external circuit (not shown) can be connected to any two of the extension tabs 146 to achieve a desired voltage.

[0018]

[0026] As shown, each of the electrochemical cells 100 has a voltage V. The voltage drop across one of the electrochemical cells 100 is V×1. In other words, the voltage drop from extension tab 146a to extension tab 146b (i.e., across electrochemical cell 100a) is V×1. As shown, the voltage drop across two of the electrochemical cells 100 (e.g., from extension tab 146a to extension tab 146c) is V×2. As shown, the voltage drop across three of the electrochemical cells 100 (e.g., from extension tab 146a to extension tab 146d) is V×3. As shown, each of the electrochemical cells 100 has approximately the same voltage V. In some embodiments, the electrochemical cells 100 can have varying voltages. In some embodiments, electrochemical cell 100a can have a first voltage and electrochemical cell 100b can have a second voltage, where the second voltage is different from the first voltage. In some embodiments, electrochemical cell 100c may have a third voltage, where the third voltage is different from the first voltage and the second voltage. As an example of varying voltages, electrochemical cell 100a may have a voltage of 1 V and electrochemical cell 100b may have a voltage of 0.5 V. In such a case, the voltage drop from extension tab 146a to extension tab 146c would be 1.5 V. In some embodiments, each of electrochemical cells 100 may have the same cell chemistry. In some embodiments, electrochemical cells 100 may have varying cell chemistries. In other words, electrochemical cell 100a may have a first cell chemistry and electrochemical cell 100b may have a second cell chemistry, where the second cell chemistry is different from the first cell chemistry. In some embodiments, electrochemical cell 100c may have a third cell chemistry, where the third cell chemistry is different from the first cell chemistry and the second cell chemistry.

[0019]

[0027] As shown, the multi-cell 1000 includes three electrochemical cells 100. In some embodiments, the multi-cell 1000 can include at least about four, at least about five, at least about six, at least about seven, at least about eight, at least about nine, 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 electrochemical cells 100. In some embodiments, the multicell 1000 can include about 100 or less, about 95 or less, about 90 or less, about 85 or less, about 80 or less, about 75 or less, about 70 or less, about 65 or less, about 60 or less, about 55 or less, about 50 or less, about 45 or less, about 40 or less, about 30 or less, about 20 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, about 6 or less, or about 5 or less electrochemical cells 100. Combinations of the above-referenced ranges of the number of electrochemical cells 100 in the multicell 1000 are also possible (e.g., at least about 4 and less than about 100 or at least about 10 and less than about 20), including all values ​​and ranges therebetween. In some embodiments, the multi-cell 1000 can include 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 electrochemical cells 100.

[0020]

[0028] As shown, the multicell 1000 includes four connection points 105. In some embodiments, the multicell 1000 can include 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 connection points 105. In some embodiments, the multicell 1000 can include about 100 or less, about 95 or less, about 90 or less, about 85 or less, about 80 or less, about 75 or less, about 70 or less, about 65 or less, about 60 or less, about 55 or less, about 50 or less, about 45 or less, about 40 or less, about 30 or less, about 20 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, or about 6 or less connection points 105. Combinations of the above-referenced ranges for the number of connection points 105 in the multicell 1000 are also possible (e.g., at least about 5 and less than about 100, or at least about 10 and less than about 20), including all values ​​and ranges therebetween. In some embodiments, the multicell 1000 can include 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 connection points 105.

[0021]

[0029] As shown, the multi-cell 1000 includes four extension tabs 146. In some embodiments, the multi-cell 1000 can include 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 extension tabs 146. In some embodiments, the multi-cell 1000 can include about 100 or less, about 95 or less, about 90 or less, about 85 or less, about 80 or less, about 75 or less, about 70 or less, about 65 or less, about 60 or less, about 55 or less, about 50 or less, about 45 or less, about 40 or less, about 30 or less, about 20 or less, about 10 or less, about 9 or less, about 8 or less, about 7 or less, or about 6 or less extension tabs 146. Combinations of the above-referenced ranges for the number of extension tabs 146 in the multi-cell 1000 are also possible (e.g., at least about 5 and less than about 100 or at least about 10 and less than about 20), including all values ​​and ranges therebetween. In some embodiments, the multi-cell 1000 can include 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 extension tabs 146.

[0022]

[0030] In some embodiments, multiple multicells 1000 may be connected in series. In some embodiments, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least about 20 multicells 1000 may be connected in series, including all values ​​and ranges therebetween. In some embodiments, multiple multicells 1000 may be connected in parallel. In some embodiments, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least about 20 multicells 1000 may be connected in parallel. In some embodiments, multiple multicells 1000 may be connected in both series and parallel in an m×n configuration. where m is a positive integer representing the number of multicells 1000 in a series of multicells 1000 and n is a positive integer representing the number of series of multicells 1000 connected in parallel. In some embodiments, m and / or n can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least about 20, including all values ​​and ranges therebetween.

[0023]

[0031] 2A-2B show an individual electrochemical cell 200 according to one embodiment. The electrochemical cell 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. The anode current collector 220 includes an anode weld tab 225, while the cathode current collector 240 includes a cathode weld tab 245. FIG. 2A is a cross-sectional view of an individual electrochemical cell 200, while FIG. 2B is a front view of an individual electrochemical cell 200 with the cathode side facing forward.

[0024]

[0032] 3A through 3E illustrate a multi-cell 3000 including multiple electrochemical cells 300-i, 300-ii, 300-iii, and 300-iv (collectively referred to as electrochemical cells 300), according to one embodiment. FIG. 3A illustrates four electrochemical cells 300, including anode weld tabs 325a, 325b, 325c, and 325d (collectively referred to as anode weld tabs 325) and cathode weld tabs 345a, 345b, 345c, and 345d (collectively referred to as cathode weld tabs 345). As shown, cathode current collectors 340a, 340b, 340c, and 340d (collectively referred to as cathode current collectors 340) are visible in FIG. 3A, while anode current collectors are on the opposite side of each electrochemical cell 300 and are therefore not shown. Electrochemical cell 300 may include each of the components described above with reference to the individual electrochemical cells 200 described above with reference to Figures 2A-2B.

[0025]

[0033] 3B shows the electrochemical cells 300 of FIG. 3A stacked to form a multi-cell 3000. As shown, each of the anode weld tabs 325 and each of the cathode weld tabs 345 are trimmed to a predetermined shape, with dotted lines representing electrical contact between adjacent electrochemical cells 300. Trimming the anode weld tabs 325 and cathode weld tabs 345 to a predetermined shape can help selectively couple (i.e., electrically and mechanically) these tabs while insulating them from undesired electrical contact. In other words, the cathode weld tab 345a of a first electrochemical cell 300-i can be coupled to the anode weld tab 325b of a second electrochemical cell 300-ii, and if both of these tabs are trimmed so that they can only contact each other, the occurrence of undesired electrical contact (i.e., short circuits) between the tabs can be reduced. 3B, cathode weld tab 345a is connected to anode weld tab 325b, cathode weld tab 345b is connected to anode weld tab 325c, and cathode weld tab 345c is connected to anode weld tab 325d. Anode weld tab 325a and cathode weld tab 345d are left to be connected to an external circuit. In some embodiments, the connection between anode weld tab 325 and cathode weld tab 345 may be made by ultrasonic welding, soldering, brazing, or any other suitable connection technique.

[0026]

[0034] 3C and 3D show additional components of the fabrication of multi-cell 3000. Multi-cell 3000 includes extension tabs 346a, 346b, 346c, 346d, and 346e (collectively referred to as extension tabs 346), insulating strips 347a and 347b (collectively referred to as insulating strips 347), and pouch 360. FIG. 3C is an exploded view of the layers of multi-cell 3000, with dotted lines representing electrical contacts. FIG. 3D is a detailed view of the connections between extension tabs 346, anode weld tab 325, and cathode weld tab 345. As shown, extension tab 346a is connected to cathode weld tab 345d, extension tab 346b is connected to anode weld tab 325c and cathode weld tab 345b, extension tab 346c is connected to anode weld tab 325a, extension tab 346d is connected to anode weld tab 325d and cathode weld tab 345c, and extension tab 346e is connected to anode weld tab 325b and cathode weld tab 345a. In some embodiments, the connections between extension tabs 346, anode weld tab 325, and cathode weld tab 345 may be made by ultrasonic welding, soldering, brazing, or any other suitable connection technique. In some embodiments, an insulating strip 347 may be connected to extension tab 346.

[0027]

[0035] In some embodiments, the insulating strip 347 can keep the extension tabs 346 from moving independently and bending in undesired directions. In some embodiments, the insulating strip 347 can help prevent undesired electrical contact between the extension tabs 346, the anode welding tab 325, or the cathode welding tab 345. In some embodiments, the insulating strip 347 can include an adhesive surface so that the extension tabs 346 are secured to the interior surface of the pouch 360. The extension tabs 346 can extend to the exterior of the pouch 360 and serve as connection points for connector wires. FIG. 3D shows, by way of example, a sample of the voltage associated with each of the extension tabs 346. If each of the electrochemical cells 300 is a lithium iron phosphate (LFP) cell, the cell voltage of each of the electrochemical cells 300 is approximately 3.2 V when fully charged. Therefore, a custom voltage can be selected for a given application based on the placement of the connector wires. For example, if a first connector wire (not shown) is connected to extension tab 346c and a second connector wire (not shown) is connected to extension tab 346a, the total voltage drop from the first connector wire to the second connector wire will be approximately 12.8V. In this configuration and example, any other multiple of 3.2V is possible. For example, if a first connector wire is connected to extension tab 346c and a second connector wire is connected to extension tab 346e, the total voltage drop from the first connector wire to the second connector wire will be approximately 3.2V.

[0028]

[0036] FIG. 3E shows the multi-cell 3000 in a fully assembled state. As shown, all of the extension tabs 346 extend to the exterior of the pouch 360. As shown and described in FIGS. 3A-3E, the multi-cell 3000 includes four electrochemical cells 300. In some embodiments, the multi-cell 3000 can include two, three, five, six, seven, eight, nine, ten, or more electrochemical cells 300. In some embodiments, multiple multi-cells 3000 can be stacked to create an electrochemical cell system. As shown, the multi-cell 3000 is contained within a pouch. In some embodiments, the multi-cell 3000 can be contained in a hard-cased can or any other suitable electrochemical cell containment means.

[0029]

[0037] 4A through 7B illustrate various physical and electrical connection schemes for joining multi-cells 3000a, 3000b, 3000c, and 3000d (collectively referred to as multi-cells 3000) according to various embodiments. Multi-cell 3000a includes series-connected electrochemical cells 300a-i, 300a-ii, 300a-iii, and 300a-iv (collectively referred to as electrochemical cells 300a). Multi-cell 3000b includes series-connected electrochemical cells 300b-i, 300b-ii, 300b-iii, and 300b-iv (collectively referred to as electrochemical cells 300b). Multi-cell 3000c includes series-connected electrochemical cells 300c-i, 300c-ii, 300c-iii, and 300c-iv (collectively referred to as electrochemical cells 300c). Multi-cell 3000d includes electrochemical cells 300d-i, 300d-ii, 300d-iii, and 300d-iv (collectively referred to as electrochemical cells 300d) connected in series. Each of multi-cell 3000 includes extension tabs 346a, 346b, 346c, 346d, and 346e (collectively referred to as extension tabs 346).

[0030]

[0038] 4A-4B illustrate a multi-cell system 30000 that includes multiple cells 3000 that are physically coupled to one another but electrically isolated from one another. FIG. 4A is a physical depiction of the multi-cell system 30000, while FIG. 4B is a circuit diagram of the multi-cell system 30000. As shown, electrochemical cell 300a is operable in one series, electrochemical cell 300b is operable in one series, electrochemical cell 300c is operable in one series, and electrochemical cell 300d is operable in one series. In other words, there is no electrical connection between electrochemical cell 300a, electrochemical cell 300b, electrochemical cell 300c, or electrochemical cell 300d. As shown, the multi-cell system 30000 includes four multi-cells 3000. In some embodiments, the multi-cell system 30000 may include 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more than about 20 multi-cells 3000, including all values ​​and ranges therebetween.

[0031]

[0039] 5A-5B illustrate a multi-cell system 40000 including multiple multi-cells 3000 connected in parallel, according to one embodiment. FIG. 5A is a physical depiction of the multi-cell system 40000, while FIG. 5B is a circuit diagram of the multi-cell system 40000. The multi-cell 40000 includes full parallel connectors 370a, 370b, 370c, 370d, and 370e (collectively referred to as full parallel connectors 370) that electrically connect the extension tabs 346 across all of the multi-cells 3000. In other words, each full parallel connector 370 connects all of the extension tabs 346 to the same reduction potential. The reduction potential is shown by way of example in the circuit diagram of FIG. 5B. As shown, electrochemical cell 300a-i is connected in parallel with electrochemical cells 300b-i, 300c-i, and 300d-i; electrochemical cell 300a-ii is connected in parallel with electrochemical cells 300b-ii, 300c-ii, and 300d-ii; electrochemical cell 300a-iii is connected in parallel with electrochemical cells 300b-iii, 300c-iii, and 300d-iii; and electrochemical cell 300a-iv is connected in parallel with electrochemical cells 300b-iv, 300c-iv, and 300d-iv. Multi-cell system 40000 has the same reduction potential at overall parallel connectors 370a, 370b, 370c, 370d, 370d, and 370e as multi-cells 3000a, 3000b, 3000c, or 3000d at extension tabs 346a, 346b, 346c, 346d, and 346e, respectively. However, multi-cell system 40000 has four times the energy capacity of multi-cells 3000a, 3000b, 3000c, or 3000d. As shown, multi-cell system 40000 includes four multi-cells 3000 and four overall parallel connectors 370. In some embodiments, the multi-cell system 30000 may include 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more than about 20 multi-cells 3000 and total parallel connectors 370, including all values ​​and ranges therebetween.

[0032]

[0040] 6A-6B illustrate a multi-cell system 50000 including multiple multi-cells 3000 connected in series, according to one embodiment. FIG. 6A is a physical depiction of the multi-cell system 50000, while FIG. 6B is a circuit diagram of the multi-cell system 50000. The multi-cell system 50000 includes series connectors 380a, 380b, and 380c (collectively referred to as series connectors 380). As shown, the series connector 380a connects the highest reduction potential extension tab (346a) of the multi-cell 3000a to the lowest reduction potential extension tab (346c) of the multi-cell 3000b. As shown, the series connector 380b connects the highest reduction potential extension tab (346a) of the multi-cell 3000b to the lowest reduction potential extension tab (346c) of the multi-cell 3000c. As shown, series connector 380c connects the extension tab (346a) with the highest reduction potential of multi-cell 3000c to the extension tab (346c) with the lowest reduction potential of multi-cell 3000d. The reduction potentials are shown by example in the circuit diagram of FIG. 6B. As shown, the voltage drop across multi-cell system 50000 is 16 times the voltage drop across a single electrochemical cell (e.g., 300a-i), while the energy capacity of multi-cell system 50000 is the same as that of a single electrochemical cell. As shown, multi-cell system 50000 includes four multi-cells 3000 connected in series. In some embodiments, the multi-cell system 50000 can include two, three, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more than about 20 multi-cells 3000, including all values ​​and ranges therebetween. As shown, the multi-cell system 50000 includes three series connectors 380. In some embodiments, the multi-cell system 50000 can include two, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more than about 20 series connectors 380, including all values ​​and ranges therebetween.

[0033]

[0041] 7A-7B illustrate a multi-cell system 60000 including multiple multi-cells 3000 connected both in series and in parallel, according to one embodiment. FIG. 7A is a physical depiction of the multi-cell system 60000, while FIG. 7B is a circuit diagram of the multi-cell system 60000. The multi-cell system 60000 includes partial parallel connectors 372a, 372b, 372c, 372d, 372e, 372f, 372g, 372h, 372i, and 372j (collectively referred to as partial parallel connectors 372) and a series connector 380. As shown, the partial parallel connectors 372 connect the extension tabs 346 between multi-cell 3000a and multi-cell 3000b, and between multi-cell 3000c and multi-cell 3000d. Series connector 380 connects multicells 3000a and 3000b to multicells 3000c and 3000d in series. Reduction potentials are shown by way of example in the circuit diagram of FIG. 7B. As shown, the voltage drop across multicell system 60000 is eight times that across a single electrochemical cell (e.g., 300a-i), while the energy capacity of multicell system 60000 is twice that of a single electrochemical cell. As shown, multicell system 60000 includes two series of multicells 3000 connected in parallel, each series of multicells 3000 including two multicells 3000. In some embodiments, multicell system 60000 may include m series of multicells 3000 connected in parallel, each series of multicells 3000 including n multicells 3000. wherein m and / or n are 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least about 20, including all values ​​and ranges therebetween.

[0034]

[0042] 8A-8C illustrate a multi-cell system 70000 including multiple multi-cells 3000a, 3000b, 3000c, and 3000d (collectively referred to as multi-cells 3000), according to one embodiment. As shown in FIGS. 8A-8C, multi-cell system 70000 includes multi-cells 3000 (each of which includes extension tabs 346), end plates 302a and 302b (collectively referred to as end plates 302), spacers 304a and 304b (collectively referred to as spacers 304), restraining straps 306a, 306b, and 306c (collectively referred to as restraining straps 306), and a BMS circuit board 360. In some embodiments, BMS circuit board 360 may include main power connections 362a and 362b (collectively referred to as main power connections 362) and contact pads 366. The multi-cell tabs 346 may be connected to the contact pads 366 by ultrasonic welding, soldering, brazing, or any other suitable joining technique. In some embodiments, the end plates 302 and restraining straps 306 may be used to provide compression and structural cohesion to the multi-cells 3000. In some embodiments, the spacers 304 may minimize physical contact between the multi-cells 3000. In some embodiments, the spacers 304 may be constructed of a soft, insulating material to minimize damage to the multi-cells 3000 while the multi-cells 3000 are compressed.

[0035]

[0043] In some embodiments, the BMS circuit board 360 may control charging and discharging within specified limits, which may be useful during the formation cycle of the electrochemical cell system 30000. By controlling charging and discharging within specified limits during the formation cycle, the evolution of various electrochemical species may be more precisely controlled and monitored. This may allow for convenient removal and replacement of the multi-cell 3000 if the multi-cell 3000 fails quality control protocols during the formation cycle. In other words, rather than replacing the entire multi-cell system 70000 or individually testing each component of the multi-cell system 70000 to find the faulty part, only a small portion of the multi-cell system 70000 may be selectively and precisely replaced.

[0036]

[0044] For quality control, voltage may be monitored through the use of the main power connection 362 and pogo pins 364. During testing, the main power connection 362 may be used to supply current to the multi-cell system 70000, while voltage monitoring is performed via the pogo pins 364. In other words, the pogo pins 364 may be part of an external quality control monitoring system. In some embodiments, the external quality control system may monitor voltage without supplying or controlling current. The current travels through a predetermined path on the BMS circuit board 360. The pogo pins 364 may be mounted above the BMS circuit board 360 and may contact the extension tabs 346 with the contact pads 366 before the extension tabs 346 are permanently connected to the contact pads 366. This level of current control may greatly reduce the number of current channels required to test the multi-cell system. As shown, the multi-cell system 70000 includes four multi-cells 3000, each including four electrochemical cells 300. Testing a multi-cell system with 16 electrochemical cells would typically require 16 current delivery channels. With the aforementioned BMS circuit board 360 in place, effective testing can be achieved with a single current delivery channel. During testing, the BMS circuit board 360 can provide charge control (i.e., top-of-charge safety monitoring and cell balancing). Because the extension tabs 346 are not yet hard-connected to the contact pads 366 on the BMS circuit board 360, reprocessing can be performed if cell replacement is desired. This concept is applicable to any electrochemical cell type. As shown, the multi-cell system 70000 includes four multi-cells 3000. In some embodiments, the multi-cell system 70000 can include two, three, five, six, seven, eight, nine, ten, or more electrochemical cell stacks.

[0037]

[0045] 9A and 9B show a multi-cell system 80000 including venting tabs 390a, 390b, 390c, and 390d (collectively referred to as venting tabs 390). When electrochemical cells 300 and multi-cells 3000 are formed, they often generate small amounts of gas, depending on the cell chemistry. Removing this gas prior to installation of the multi-cell system 80000 is an important safety precaution. Removal of gas from the cell pouch is often accomplished by trimming a portion of the pouch's heat seal, applying a vacuum, and then resealing the pouch. By positioning the venting tabs 390 away from the contact points between the multi-cells 3000 and away from the restraining straps 306, venting of the multi-cell system 80000 can be accomplished in situ in a single operation. Additionally, the restraining straps 306 and end plates 302 can apply a clamping pressure. Applying a clamping pressure can reduce or completely eliminate the use of a vacuum. This reduction in processing steps can significantly reduce the cost of producing the multi-cell system 80000.

[0038]

[0046] Some embodiments and / or methods described herein may be implemented by software (executed on hardware), hardware, or a combination thereof. Hardware modules may include, for example, general-purpose processors, field-programmable gate arrays (FPGAs), and / or application-specific integrated circuits (ASICs). Software modules (executed on hardware) may be expressed in various software languages ​​(e.g., computer code), including C, C++, Java™, Ruby, Visual Basic™, and / or other object-oriented, procedural, or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions such as those generated by a compiler, code used to create web services, and files containing higher-level instructions executed by a computer using an interpreter. For example, embodiments may be implemented using imperative programming languages ​​(e.g., C, Fortran, etc.), functional programming languages ​​(e.g., Haskell, Erlang, etc.), logic programming languages ​​(e.g., Prolog), object-oriented programming languages ​​(e.g., Java, C++, etc.), or other suitable programming languages ​​and / or development tools. Further examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0039]

[0047] Various concepts may be embodied as one or more methods, at least one example of which is provided. Acts performed as part of a method may be arranged in any suitable order. Thus, embodiments may be constructed to perform acts in an order different from that illustrated, which may include performing some acts simultaneously, even if shown as sequential acts in the illustrated embodiment. Stated differently, it should be understood that such features are not necessarily limited to a particular order of execution, but rather any number of threads, processes, services, servers, and / or the like may execute sequentially, asynchronously, simultaneously, in parallel, simultaneously, synchronously, and / or similarly in a manner consistent with the present disclosure. Thus, some of these features may be inconsistent with one another in that they may not simultaneously exist in a single embodiment. Similarly, some features may be applicable to some aspects of the innovations and not to other aspects.

[0040]

[0048] Additionally, the present disclosure may include other innovations not currently described. Applicant reserves all rights with respect to such innovations, including the right to embody such innovations and to file additional applications, continuations, continuations-in-part, divisional applications, and / or the like. Accordingly, it should be understood that advantages, embodiments, examples, functionals, features, logical, operational, organizational, structural, topological, and / or other aspects of the present disclosure should not be considered limitations on the present disclosure as defined by the embodiments or limitations on equivalents of the embodiments. Depending on the particular desires and / or characteristics of individual and / or business users, database organization and / or relational models, data types, data transmission and / or network frameworks, syntax structures, and / or the like, various embodiments of the technology disclosed herein can be implemented to allow for much of the flexibility and customization described herein.

[0041]

[0049] All definitions and definitions used herein should be understood to govern dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0042]

[0050] As used herein, particularly in the embodiments, the term "about" or "approximately," when preceding a numerical value, indicates a range of plus or minus 10% of that value. When a range of values ​​is presented, unless the context clearly dictates otherwise, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range, and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges, which may be independently included in the smaller ranges, are also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. When a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included within the disclosure.

[0043]

[0051] The indefinite articles "a" and "an" as used in this specification and embodiments should be understood to mean "at least one" unless expressly stated otherwise.

[0044]

[0052] The phrase "and / or" as used in this specification and in the embodiments should be understood to mean "either or both" of the elements conjoined thereby, i.e., elements that are sometimes conjunctive and sometimes disjunctive. Multiple elements listed with "and / or" should be interpreted similarly, i.e., "one or more" of the elements conjoined thereby. Other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether related or unrelated to those specifically identified elements. Thus, as a non-limiting example, when used in connection with open-ended language such as "comprising," "A and / or B" may refer in some embodiments to A only (optionally including elements other than B); in other embodiments to B only (optionally including elements other than A); in yet other embodiments to both A and B (optionally including other elements); and so on.

[0045]

[0053] As used in the specification and embodiments, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating listed items, "or" or "and / or" should be interpreted as inclusive, i.e., including at least one but more than one of the several or listed elements, and optionally further unlisted items. Only terms expressly stated otherwise, such as "only one of" or "only one of," or, when used in the embodiments, "consisting of," refer to the inclusion of only one element of the several or listed elements. Generally, the term "or" as used herein should only be interpreted as indicating exclusive alternatives (i.e., "one or the other, but not both") when preceded by terms of exclusivity such as "either," "one of," "only one of," or "only one of." "Consisting essentially of," when used in the embodiments, should have its ordinary meaning as used in the field of patent law.

[0046]

[0054] As used herein and in the embodiments, the phrase "at least one" referring to a list of one or more elements should be understood to mean at least one element selected from any one or more of the elements in that list of elements, but not necessarily including at least one of each and every element specifically listed in that list of elements, and not excluding any combinations of elements in that list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related 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 in some embodiments to at least one, optionally more than one, A, with no B (and optionally including elements other than B); in some other embodiments to at least one, optionally more than one, B, with no A (and optionally including elements other than A); in some other embodiments to at least one, optionally more than one, A and at least one, optionally more than one, B (and optionally including other elements); and so on.

[0047]

[0055] In the embodiments, as well as in the foregoing specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like, are to be understood to be open-ended, i.e., to mean including but not limited to. As set forth in the United States Manual of Patent Examining Procedures at 2111.03, only the transitional phrases "consisting of" and "consisting essentially of" are considered closed or semi-closed transitional phrases, respectively.

[0048]

[0056] While specific embodiments of the present disclosure have been outlined above, many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the embodiments described herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the present disclosure. While the methods and steps described above indicate certain events occurring in a particular order, those skilled in the art having the benefit of this disclosure will recognize that the ordering of certain steps may be modified, and such modifications are in accordance with variations of the invention. Also, certain of the steps may be performed simultaneously in parallel processing, where possible, or sequentially as described above. While embodiments have been individually shown and described in detail, it will be understood that various changes in form and detail may be made.

Claims

1. a plurality of electrochemical cells; Each of the plurality of electrochemical cells comprises: an anode disposed on an anode current collector including an anode tab; a cathode disposed on a cathode current collector including a cathode tab; a separator disposed between the anode and the cathode; Equipped with the cathode tab of a first electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a second electrochemical cell of the plurality of electrochemical cells at a first connection point; the cathode tab of a second electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a third electrochemical cell of the plurality of electrochemical cells at a second connection point; The plurality of electrochemical cells are disposed within a single pouch.

2. the cathode tab of the first electrochemical cell and the anode tab of the second electrochemical cell are trimmed so that the cathode tab of the first electrochemical cell is in physical contact with the anode tab of the second electrochemical cell and the cathode tab of the first electrochemical cell is not in physical contact with any other tab; 10. The multi-cell of claim 1, wherein the cathode tab of the second electrochemical cell and the anode tab of the third electrochemical cell are trimmed so that the cathode tab of the second electrochemical cell is in physical contact with the anode tab of the third electrochemical cell and the cathode tab of the first electrochemical cell is not in physical contact with any other tab.

3. a first extension tab connected to the first connection point and extending outside the single pouch; a second extension tab connected to the second connection point and extending outside the single pouch; The multi-cell of claim 1 further comprising:

4. an anode disposed on an anode current collector including an anode tab; a cathode disposed on a cathode current collector including a cathode tab; a separator disposed between the anode and the cathode; a fourth electrochemical cell comprising:

10. The multi-cell of claim 1, wherein the cathode tab of a third electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a fourth electrochemical cell of the plurality of electrochemical cells at a third connection point.

5. The multi-cell of claim 4 , further comprising an extension tab connected to the third connection point, the third extension tab extending outside the single pouch.

6. It has multiple multi-cells, Each of the multi-cells is a multi-cell according to claim 1, A multi-cell system, wherein each of the multiple cells is physically connected to one another.

7. The multi-cell system of claim 6 , wherein the plurality of multi-cells are connected in parallel.

8. The multi-cell system of claim 6 , wherein the plurality of multi-cells are connected in series.

9. The multi-cell system of claim 6 , wherein the plurality of multi-cells are connected in both series and parallel.

10. The multi-cell system of claim 6 , further comprising a battery management system configured to monitor a state of charge of each electrochemical cell of the plurality of electrochemical cells.

11. 7. The multi-cell system of claim 6, wherein each multi-cell includes a venting tab, each venting tab configured to release gas from each multi-cell when cut.

12. a plurality of electrochemical cells connected in series; Each of the plurality of electrochemical cells comprises: an anode disposed on an anode current collector including an anode tab; a cathode disposed on a cathode current collector including a cathode tab; a separator disposed between the anode and the cathode; Equipped with the cathode tab of a first electrochemical cell of the plurality of electrochemical cells physically contacts the anode tab of a second electrochemical cell of the plurality of electrochemical cells, and the cathode tab of the first electrochemical cell does not contact any other tab; a cathode tab of a second electrochemical cell of the plurality of electrochemical cells physically contacts the anode tab of a third electrochemical cell of the plurality of electrochemical cells, and the cathode tab of the second electrochemical cell does not contact any other tabs.

13. The multi-cell of claim 12 , wherein the plurality of electrochemical cells are disposed within a single pouch.

14. a first extension tab coupled to the cathode tab of the first electrochemical cell and the anode tab of the second electrochemical cell; a second extension tab coupled to the cathode weld tab of the second electrochemical cell and the anode weld tab of the third electrochemical cell; The multi-cell of claim 12 further comprising:

15. an anode disposed on an anode current collector including an anode tab; a cathode disposed on a cathode current collector including a cathode tab; a separator disposed between the anode and the cathode; a fourth electrochemical cell comprising:

13. The multi-cell of claim 12, wherein the cathode tab of a third electrochemical cell of the plurality of electrochemical cells is connected to the anode tab of a fourth electrochemical cell of the plurality of electrochemical cells, and the cathode tab of the third electrochemical cell does not contact any other tabs.

16. 16. The multi-cell of claim 15, further comprising an extension tab connected to the cathode tab of the third electrochemical cell and the anode tab of the fourth electrochemical cell.

17. It has multiple multi-cells, Each multi-cell comprises a plurality of electrochemical cells connected in series; Each multi-cell includes a terminal anode tab and a terminal cathode tab; a terminal cathode tab of a first multi-cell of the plurality of multi-cells electrically coupled to either a terminal anode tab or a terminal cathode tab of a second multi-cell of the plurality of multi-cells.

18. 20. The multi-cell system of claim 17, wherein the terminal cathode tab of the first multi-cell of the plurality of multi-cells is electrically coupled to the terminal cathode tab of the second multi-cell of the plurality of multi-cells.

19. 20. The multi-cell system of claim 17, wherein the terminal cathode tab of the first multi-cell of the plurality of multi-cells is electrically coupled to the terminal anode tab of the second multi-cell of the plurality of multi-cells.

20. 20. The multi-cell system of claim 18, wherein a terminal cathode tab of the second multi-cell of the plurality of multi-cells is electrically coupled to a terminal cathode tab of a third multi-cell of the plurality of multi-cells.

21. 21. The multi-cell system of claim 20, wherein a terminal cathode tab of the second multi-cell of the plurality of multi-cells is electrically coupled to a terminal anode tab of a third multi-cell of the plurality of multi-cells.

22. 20. The multi-cell system of claim 17, further comprising a battery management system configured to control charging and discharging of the plurality of multi-cells within specified limits.

23. 20. The multi-cell system of claim 17, wherein each multi-cell of the plurality of electrochemical cells is disposed within a single pouch.

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