Battery Formation Method

Abstract

The method includes the steps of placing a lithium-containing secondary battery within a pouch defined by an enclosure; trimming the enclosure to form a plurality of flaps; attaching a first side flap and a second side flap of the plurality of flaps to the pouch by folding each of the first and second side flaps toward and into contact with the pouch, where a portion of the first side flap extends beyond the pouch to define a first tab and a portion of the second side flap extends beyond the pouch to define a second tab; attaching an end flap of the plurality of flaps to the pouch by folding the end flap toward and into contact with the pouch; and attaching the first tab and the second tab to the end flap by folding the first tab and the second tab toward and into contact with the end flap.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 326,112, filed March 31, 2022, the disclosure of which is incorporated by reference in its entirety herein.

[0002] The field of the disclosure relates generally to the formation of secondary batteries, and more specifically, to methods of forming secondary battery assemblies following a pre-lithiation process. [Background technology]

[0003] In a rocking chair battery cell, both the positive and negative electrodes of the secondary battery contain a material into which carrier ions, such as lithium, can be inserted and extracted. When the battery is discharged, carrier ions are extracted from the negative electrode and inserted into the positive electrode. When the battery is charged, carrier ions are extracted from the positive electrode and inserted into the negative electrode.

[0004] After the lithium-containing secondary battery is assembled, the assembled battery is typically subjected to a formation process. During the formation process, the battery is slowly charged and discharged one or more times. At least some known formation processes include a pre-lithiation process to add lithium to the battery. In some cases, following the pre-lithiation process, it may be desirable to remove one or more auxiliary electrodes used in the pre-lithiation process to reduce the footprint and increase the energy density of the secondary battery. Summary of the Invention

[0005] One embodiment includes a method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, where each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The method includes disposing the lithium-containing secondary battery within a pouch defined by an enclosure, trimming the enclosure to form a plurality of flaps including a first side flap extending from the pouch at a first fold line, a second side flap extending from the pouch at a second fold line, and an end flap extending from the pouch at a third fold line, and attaching the first and second side flaps to the pouch by folding each of the first and second side flaps toward and into contact with the pouch about their respective first and second fold lines. A portion of the first side flap extends beyond the pouch to define a first tab and a portion of the second side flap extends beyond the pouch to define a second tab. The method further includes attaching the end flap to the pouch by folding the end flap about the third fold line toward and into contact with the pouch, and attaching the first tab and the second tab to the end flap by folding each of the first tab and the second tab toward and into contact with the end flap.

[0006] Another embodiment includes a method of forming a lithium-containing secondary battery disposed within a pouch defined by an enclosure. The lithium-containing battery includes a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, where each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter structure. The enclosure includes a plurality of flaps extending outwardly from the pouch, the plurality of flaps including a first side flap extending from the pouch at a first fold line, a second side flap extending from the pouch at a second fold line, and an end flap extending from the pouch at a third fold line. The method includes the steps of applying an adhesive to at least one of the first side flap and the pouch, the second side flap and the pouch, and at least one of the end flap and the pouch; folding the first side flap toward the pouch about a first fold line, where a portion of the first side flap extends beyond the pouch to define a first tab; folding the second side flap toward the pouch about a second fold line, where a portion of the second side flap extends beyond the pouch to define a second tab; and folding the first side flap toward the pouch about a second fold line, where a portion of the second side flap extends beyond the pouch to define a second tab. and the second side flap against the pouch; folding the end flap around the third fold line toward and in contact with the pouch; applying adhesive to at least one of the end flap and each of the first and second tabs after the end flap is folded into contact with the pouch; connecting the first and second tabs to the end flap by folding the first and second tabs toward and in contact with the end flap; and pressing the end flap, the first tab, and the second tab against the pouch.

[0007] Another embodiment includes a method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, where each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The method includes the steps of disposing the lithium-containing secondary battery in a pouch defined by an enclosure, disposing an auxiliary electrode in the pouch such that the auxiliary electrode contacts the lithium-containing secondary battery, performing a buffering process on the lithium-containing secondary battery, thereby transferring carrier ions from the auxiliary electrode to the lithium-containing secondary battery, removing the auxiliary electrode from the pouch after the buffering process, sealing the enclosure with the secondary battery disposed in the pouch after removing the auxiliary electrode from the pouch, and trimming the sealed enclosure to form a plurality of flaps in the enclosure, each flap extending outwardly from the pouch at a respective fold line, the plurality of flaps extending from a first sub-slot to a second sub-slot. the first and second side flaps being attached to the pouch by folding each of the first and second side flaps toward and in contact with the pouch, where a portion of the first side flap extends beyond the pouch to define a first tab and a portion of the second side flap extends beyond the pouch to define a second tab; attaching the end flap to the pouch by folding the end flap toward and in contact with the pouch; and attaching the first and second tabs to the end flap by folding each of the first and second tabs toward and in contact with the end flap.

[0008] Another embodiment includes a method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, where each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The method includes disposing a lithium-containing secondary battery within a pouch defined by an enclosure, the enclosure including a first enclosure layer and a second enclosure layer joined to the first enclosure layer, the pouch including a base defined by the first enclosure layer, a cover opposite the base and defined by the second enclosure layer, a first sidewall extending from the base to the cover, a second sidewall opposite the first sidewall and extending from the base to the cover, a first end wall extending from the first sidewall to the second sidewall and from the base to the cover, and a second end wall opposite the first end wall and extending from the first sidewall to the second sidewall and from the base to the cover, where first and second terminals of the secondary battery extend outwardly from the second end wall. The method further includes trimming the enclosure to form a plurality of flaps within the enclosure, each flap extending outwardly from the pouch at a respective fold line and including a first surface defined by the first enclosure layer and an opposing second surface defined by the second enclosure layer, the plurality of flaps including a first side flap extending from a first side wall of the pouch at the first fold line, a second side flap extending from a second side wall of the pouch at a second fold line, and an end flap extending from a first end wall of the pouch at a third fold line.The method includes the steps of applying an adhesive to at least one of a first surface of a first side flap and a first side wall of the pouch, a first surface of a second side flap and a second side wall of the pouch, and a first surface of an end flap and a first end wall of the pouch; folding the first side flap about a first fold line toward and in contact with the first side wall of the pouch, a portion of the first side flap extending beyond the first end wall of the pouch to define a first tab; folding the second side flap about a second fold line toward and in contact with the second side wall of the pouch, a portion of the second side flap extending beyond the first end wall of the pouch to define a second tab; and heating the first side flap to the pouch while heating at a first temperature for a first pressing time. the first tab and the second tab against the first side wall of the pouch; folding the end flap about the third fold line toward and in contact with the first end wall of the pouch; applying adhesive to at least one of the second surface of the end flap and the first surface of each of the first and second tabs after the end flap is folded into contact with the first end wall of the pouch; folding the first tab about a fourth fold line toward and in contact with the second surface of the end flap; folding the second tab about a fifth fold line toward and in contact with the second surface of the end flap; and pressing the end flap, the first tab, and the second tab against the first end wall of the pouch while heating at a second temperature for a second pressing time.

[0009] Various refinements exist on the features mentioned in relation to the above aspects. Further features may be incorporated into the above aspects. These refinements and additional features may exist individually or in any combination. For example, various features discussed below in relation to any of the illustrated embodiments may be incorporated alone or in any combination into any of the above aspects. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of an exemplary embodiment of a secondary battery. [Diagram 2] 2 shows a unit cell of the secondary battery of FIG. 1. [Diagram 3] 3 illustrates an exemplary cathode structure for the unit cell of FIG. 2. [Figure 4] The anode structure of the unit cell of FIG. [Diagram 5] FIG. 1 illustrates a perspective view of an exemplary embodiment of a cushioning system. [Figure 6] 6 shows an exploded view of the cushioning system of FIG. 5. [Figure 7] 1 illustrates a perspective view of an exemplary embodiment of an auxiliary electrode. [Figure 8] 8 shows an exploded view of the auxiliary electrode of FIG. 7. [Figure 9] 8 is a perspective view of the auxiliary electrode of FIG. 7 at a stage in the assembly process of the auxiliary electrode of FIG. 7. [Figure 10] 8 is a perspective view of the auxiliary electrode of FIG. 7 at another stage in the assembly process of the auxiliary electrode of FIG. 7. [Figure 11] 8 is a perspective view of the auxiliary electrode of FIG. 7 at yet another stage in the assembly process of adding an extending tab to the auxiliary electrode of FIG. 7. [Figure 12] 6 is a perspective view of the cushioning system of FIG. 5 at one stage in the assembly process of the cushioning system. [Figure 13] 6 is a perspective view of the cushioning system of FIG. 5 at another stage in the assembly process of the cushioning system. [Figure 14] 6 is a perspective view of the cushioning system of FIG. 5 at yet another stage in the assembly process of the cushioning system. [Figure 15] FIG. 15 is a cross-sectional view of a portion of the cushioning system of FIG. [Figure 16] 6 is a perspective view of the cushioning system of FIG. 5 at yet another stage in the assembly process of the cushioning system. [Figure 17] FIG. 6 is a perspective view of the buffering system of FIG. 5 after performing a buffering process on the secondary battery. [Figure 18]1 is a flowchart of a method of pre-lithiating a secondary battery with carrier ions using an auxiliary electrode of an exemplary embodiment. [Figure 19] 19 is a flowchart depicting further details of the method of FIG. 18. [Figure 20] 19 is a flowchart depicting further details of the method of FIG. 18. [Figure 21] 19 is a flowchart depicting further details of the method of FIG. 18. [Figure 22] 1 is a flowchart of an exemplary method of forming a secondary battery assembly, for example, following a pre-lithiation process or a buffering process to prepare the secondary battery assembly for an end use application. [Diagram 23] FIG. 2 is a front perspective view of an exemplary secondary battery assembly at an intermediate stage of formation. [Figure 24] FIG. 24 is a rear perspective view of the secondary battery assembly of FIG. 23. [Diagram 25] FIG. 24 is another front perspective view of the secondary battery assembly of FIG. 23. [Figure 26] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. [Figure 27] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. [Figure 28] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. [Figure 29] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. [Diagram 30] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. [Diagram 31] 24 illustrates steps of an exemplary method for forming the secondary battery assembly of FIG. 23. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] definition As used herein, "A," "an," and "the" (i.e., singular) refer to plural referents unless the context clearly dictates otherwise. For example, in one instance, reference to "an electrode" includes both a single electrode and a plurality of similar electrodes.

[0012] As used herein, "about" and "approximately" refer to plus or minus 10%, 5%, or 1% of the stated value. For example, in one example, about 250 micrometers (μm) includes 225 μm to 275 μm. As a further example, in one example, about 1,000 μm includes 900 μm to 1,100 μm. Unless otherwise indicated, all numbers expressing quantities (e.g., measurements, etc.) and the like used in the specification and claims should be understood in all instances as being modified by the term "about". Accordingly, unless otherwise indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximations. Each numerical parameter should be construed, at least in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0013] "Anode" as used herein in the context of a secondary battery refers to the negative electrode in the secondary battery.

[0014] As used herein, "anode material" or "anode active" means a material suitable for use as the negative electrode of a secondary battery.

[0015] "Cathode" as used herein in the context of a secondary battery refers to the positive electrode in the secondary battery.

[0016] As used herein, "cathode material" or "cathode active" means a material suitable for use as the positive electrode of a secondary battery.

[0017] "Conversion chemically active material" or "conversion chemistry" refers to a material that undergoes a chemical reaction during the charge and discharge cycle of a secondary battery.

[0018] As used herein, "counter electrode" may refer to the negative or positive electrode (anode or cathode) opposite an electrode of a secondary battery, unless the context clearly indicates otherwise.

[0019] As used herein, "counter electrode current collector" may refer to the negative or positive (anode or cathode) current collector on the opposite side of an electrode current connector of a secondary battery, unless the context clearly indicates otherwise.

[0020] As used herein in the context of cycling a secondary battery between a charging state and a discharging state, "cycling" refers to charging and / or discharging the battery to move the battery in a cycle from a first state, either a charging state or a discharging state, to a second state that is the opposite of the first state (i.e., the charging state if the first state was discharged, or the discharging state if the first state was charged), and then returning the battery to the first state to complete the cycle. For example, a single cycle of a secondary battery between a charging state and a discharging state may include charging the battery from the discharging state to the charging state, as in a charging cycle, and then discharging to the discharging state to complete the cycle. A single cycle may also include discharging the battery from the charging state to the discharging state, as in a discharging cycle, and then charging to the charging state to complete the cycle.

[0021] As used herein, "electrochemically active material" means an anode active material or a cathode active material.

[0022] As used herein, "electrode" may refer to either the negative or positive electrode (anode or cathode) of a secondary battery, unless the context clearly indicates otherwise.

[0023] As used herein, "electrode current collector" may refer to either the negative or positive (anode or cathode) current collector of a secondary battery, unless the context clearly indicates otherwise.

[0024] As used herein, "electrode material" may refer to either an anode material or a cathode material, unless the context clearly indicates otherwise.

[0025] As used herein, "electrode structure" may refer to an anode structure (e.g., anode structure) or a cathode structure (e.g., cathode structure) adapted for use in a battery, unless the context clearly indicates otherwise.

[0026] "Capacity" or "C", as used herein, unless the context clearly indicates otherwise, refers to the amount of charge that a battery (or a subportion of a battery that includes one or more pairs of electrode and counter electrode structures forming a bilayer) can deliver at a given voltage.

[0027] "Electrolyte," as used herein, unless the context clearly indicates otherwise, refers to a non-metallic liquid, gel, or solid material adapted for use in a battery in which electrical current is carried by the movement of ions.

[0028] As used herein in the context of the condition of a secondary battery, "state of charge" refers to a state in which a secondary battery is charged to at least 75% of its rated capacity, unless the context clearly indicates otherwise. For example, a battery may be charged to at least 80% of its rated capacity, at least 90% of its rated capacity, or even at least 95% of its rated capacity, such as 100% of its rated capacity.

[0029] "Discharge capacity," as used herein with respect to the negative electrode, means the amount of carrier ions available for extraction from the negative electrode and insertion into the positive electrode during a discharge operation of the battery between a given set of cell end-of-charge and cell end-of-discharge voltage limits, unless the context clearly indicates otherwise.

[0030] A "discharged state," as used herein in the context of the state of a secondary battery, refers to a state in which a secondary battery is discharged to less than 25% of its specified capacity, unless the context clearly indicates otherwise. For example, a battery may be discharged to less than 20% of its rated capacity, such as less than 10% of its rated capacity, or even less than 5% of its rated capacity, such as 0% of its rated capacity.

[0031] "Reversible Coulombic capacity," as used herein with reference to an electrode (i.e., positive, negative, or auxiliary electrode), means the total capacity of the electrode for carrier ions available for reversible exchange with the counter electrode.

[0032] As used herein, the terms "longitudinal axis", "lateral axis", and "vertical axis" refer to axes that are perpendicular to one another (i.e., each is perpendicular to the other). For example, the terms "longitudinal axis", "lateral axis", and "vertical axis" used herein are similar to a Cartesian coordinate system used to define three-dimensional aspects or orientations. As such, the description of the elements of the subject matter disclosed herein is not limited to the particular axis(es) used to describe the three-dimensional orientation of the elements. Alternatively stated, the axes may be interchangeable when referring to three-dimensional aspects of the subject matter disclosed herein.

[0033] As used herein, "composite material" or "composite" refers to a material that includes two or more constituent materials, unless the context clearly indicates otherwise.

[0034] As used herein, "porosity" or "porosity" or "void volume fraction" refers to a measurement of void (i.e., empty) space in a material and is the fraction of the volume of voids relative to the total volume of the material as a percentage from 0 to 1, or 0% to 100%.

[0035] "Polymer," as used herein, unless the context clearly indicates otherwise, may refer to a substance or material composed of repeating macromolecular subunits.

[0036] As used herein, unless the context clearly indicates otherwise, "microstructure" may refer to the structure of the surface of a material as revealed by an optical microscope at a magnification of greater than about 25 times.

[0037] As used herein, unless the context clearly indicates otherwise, "microporous" may refer to a material that contains pores having diameters of less than about 2 nanometers.

[0038] As used herein, unless the context clearly indicates otherwise, "macroporous" may refer to a material that contains pores having diameters greater than about 50 nanometers.

[0039] As used herein, "nanoscale" or "nanoscopic scale" can refer to structures having length scales ranging from about 1 nanometer to about 100 nanometers.

[0040] As used herein, "pre-lithiation" or "pre-lithiating" may refer to the addition of lithium to the active lithium content of a lithium-containing secondary battery as part of the formation process prior to operation of the battery to compensate for the loss of active lithium. "Pre-lithiation" or "pre-lithiating" is also referred to herein as a "buffer process."

[0041] Detailed Description Figure 1 is a perspective view of an exemplary embodiment of a secondary battery 100, and Figure 2 shows a unit cell 200 for the secondary battery 100. The secondary battery 100 of Figure 1 has an exposed portion that shows a portion of the internal structure of the secondary battery, as described further below.

[0042] As illustrated in FIG. 1, the secondary battery 100 includes a plurality of adjacent subunits 102. Each of the electrode subunits 102 has dimensions of an X-axis, a Y-axis, and a Z-axis, respectively. The X-axis, the Y-axis, and the Z-axis are each perpendicular to each other, similar to a Cartesian coordinate system. As used herein, the dimension of each electrode subunit 102 in the Z-axis may be referred to as the "height", the dimension in the X-axis may be referred to as the "length", and the dimension in the Y-axis may be referred to as the "width". The electrode subunits 102 may be combined into one or more unit cells 200 (see FIG. 2). Each of the unit cells 200 includes at least one anode active material layer 104 and at least one cathode active material layer 106. The anode active material layer 104 and the cathode active material layer 106 are electrically insulated from each other by a separator layer 108. It should be understood that in a preferred embodiment of the present disclosure, any number of electrode subunits 102 may be used in the secondary battery 100, such as 1 to 200 or more electrode subunits 102.

[0043] Referring to FIG. 1, the secondary battery 100 includes a first bus bar 110 and a second bus bar 112, which are in electrical contact with the anode active material layer 104 and the cathode active material layer 106 of each of the electrode subunits 102, respectively, via electrode tabs 114. The electrode tabs 114 are only visible on a first side 120 of the secondary battery 100 in FIG. 1, but a different set of electrode tabs 114 is present on a second side 121 of the secondary battery. The electrode tabs 114 on the first side 120 of the secondary battery 100 are electrically coupled to the first bus bar 110, which may be referred to as an anode bus bar. The electrode tabs 114 on the second side 121 of the secondary battery 100 (not visible in FIG. 1) are electrically coupled to the second bus bar 112, which may be referred to as a cathode bus bar. In this embodiment, the first bus bar 110 is electrically coupled to a first electrical terminal 124 of the secondary battery 100, which is electrically conductive. If the first bus bar 110 comprises a positive bus bar for the secondary battery 100, the first electrical terminal 124 comprises a negative terminal for the secondary battery 100. Further, in this embodiment, the second bus bar 112 is electrically coupled to a second electrical terminal 125 of the secondary battery 100, which is electrically conductive. If the second bus bar 112 comprises a negative bus bar for the secondary battery 100, the second electrical terminal 125 comprises a positive terminal for the secondary battery 100.

[0044] In one embodiment, a casing 116, which may be referred to as a constraint, may be applied over one or both of the XY surfaces of the secondary battery 100. In the embodiment shown in Figure 1, the casing 116 includes a number of perforations 118 to facilitate electrolyte distribution or flow once the secondary battery 100 is fully assembled. In one embodiment, the casing 116 includes stainless steel, such as SS301, SS316, 440C, or 440C hard. In other embodiments, the casing 116 is made of aluminum (e.g., aluminum 7075-T6, hard H18, etc.), titanium (e.g., 6A1-4V), beryllium, beryllium copper (hard), copper (O2 free, hard), nickel, other metals or metal alloys, composites, polymers, ceramics (e.g., alumina (e.g., sintered or Coorstek AD96), zirconia (e.g., Coorstek YZTP), yttria stabilized zirconia (e.g., ENrG E-Strate®)), glass, tempered glass, polyetheretherketone (PEEK) (e.g., Aptiv 1102), PEEK with carbon (e.g., Victrex 90HMF40 or Xycomp 1000-04), polyphenylene sulfide (PPS) with carbon (e.g., Tepex Dynalite 207), 30% Polyetheretherketone (PEEK) glass (e.g., Victrex 90HMF40 or Xycomp 1000-04), Polyimide (e.g., Kapton®), E Glass Std Fabric / Epoxy, 0°, E Glass UD / Epoxy, 0°, Kevlar Std Fabric / Epoxy, 0°, Kevlar UD / Epoxy, 0°, Carbon Std Fabric / Epoxy, 0°, Carbon UD / Epoxy, 0°, Toyobo Zylon® HM Fiber / Epoxy, Kevlar 49 Aramid Fiber, S Glass Fibers, Carbon Fibers, Vectran UM LCP Fibers, Dyneema, Zylon, or other suitable materials.

[0045] In some embodiments, the casing 116 comprises a sheet having a thickness ranging from about 10 to about 100 micrometers (μm). In one embodiment, the casing 116 comprises a stainless steel sheet (e.g., SS316) having a thickness of about 30 μm. In another embodiment, the casing 116 comprises an aluminum sheet (e.g., 7075-T6) having a thickness of about 40 μm. In another embodiment, the casing 116 comprises a zirconia sheet (e.g., Coorstek YZTP) having a thickness of about 30 μm. In another embodiment, the casing 116 comprises an E-glass UD / epoxy 0 degree sheet having a thickness of about 75 μm. In another embodiment, the casing 116 comprises 12 μm carbon fiber with a packing density of >50%.

[0046] In this embodiment, secondary battery 100 includes a first major surface 126 and a second major surface 127 opposite first major surface 126. Major surfaces 126, 127 of secondary battery 100 may be substantially planar in some embodiments.

[0047] Referring to FIG. 2, which shows the secondary battery 100 along the cut line DD in FIG. 1, individual layers of a unit cell 200, which may be the same or similar to the electrode subunit 102, are depicted. For each of the unit cells 200, in some embodiments, the separator layer 108 is an ion-permeable microporous polymeric material suitable for use as a separator in a secondary battery. In one embodiment, the separator layer 108 is coated with ceramic particles on one or both sides. In this embodiment, the unit cell 200 includes a positive electrode current collector 202 in the center, which may include or be electrically coupled to one of the electrode tabs 114 on one of the sides 120, 121 of the secondary battery 100 (see FIG. 1). The unit cell 200 further includes, in a laminated structure, a positive electrode active material layer 104, a separator layer 108, a negative electrode active material layer 106, and a negative electrode current collector 204. The negative electrode current collector 204 may include or be electrically coupled to one of the electrode tabs 114 on one of the sides 120 , 121 of the secondary battery 100 that is different from the positive electrode current collector 202 .

[0048] In an alternative embodiment, the arrangement of the cathode active material layer 106 and the anode active material layer 104 may be swapped such that the cathode active material layer is toward the center and the anode active material layer is distal to the cathode active material layer. In one embodiment, unit cell 200A includes, stacked in succession from left to right, an anode current collector 202, an anode active material layer 104, a separator layer 108, a cathode active material layer 106, and a cathode current collector 204. In an alternative embodiment, unit cell 200B includes, stacked in succession from left to right, a separator layer 108, a first layer of cathode active material layer 106, a cathode current collector 204, a second layer of cathode active material layer 106, a separator layer 108, a first layer of anode active material layer 104, an anode current collector 202, a second layer of anode active material layer 104, and a separator layer 108.

[0049] 2 , the layered structure comprising the cathode active material layer 106 and the cathode current collector 204 may be referred to as a cathode structure 206, while the layered structure comprising the anode active material layer 104 and the anode current collector 202 may be referred to as an anode structure 207. Collectively, the collection of cathode structures 206 for the secondary battery 100 may be referred to as the positive electrode 208 of the secondary battery 100, and the collection of anode structures 207 for the secondary battery 100 (only one of the anode structures 207 is shown in FIG. 2 ) may be referred to as the negative electrode 209 of the secondary battery 100.

[0050] A voltage difference V exists between adjacent cathode structures 206 and anode structures 207, the adjacent structures being considered bilayers in some embodiments. Each bilayer has a capacity C determined by the configuration and construction of the cathode structures 206 and anode structures 207. In this embodiment, each bilayer produces a voltage difference of about 4.35 volts. In other embodiments, each bilayer has a voltage difference of about 0.5 volts, about 1.0 volts, about 1.5 volts, about 2.0 volts, about 2.5 volts, about 3.0 volts, about 3.5 volts, about 4.0 volts, 4.5 volts, about 5.0 volts, 4-5 volts, or any other suitable voltage. During cycling between charge and discharge states, the voltage may vary, for example, between about 2.5 volts and about 4.35 volts. The capacity C of the bilayer in this embodiment is about 3.5 milliamp hours (mAh). In other embodiments, the capacity C of the bilayer is about 2 mAh, less than 5 mAh, or any other suitable capacity. In some embodiments, the capacity C of the bilayer can be up to about 10 mAh.

[0051] The cathode current collector 204 may include aluminum, nickel, cobalt, titanium, and tungsten, or alloys thereof, or any other material suitable for use as a cathode current collector layer. 3 For example, in one such embodiment, the cathode current collector 204 has a conductivity of at least about 10 4 By way of further example, in one such embodiment, the cathode current collector 204 has a conductivity of at least about 10 5The cathode current collector 204 has a conductivity of Siemens / cm. In general, the cathode current collector 204 may include a metal such as aluminum, carbon, chromium, gold, nickel, NiP, palladium, platinum, rhodium, ruthenium, alloys of silicon and nickel, titanium, or combinations thereof (see A.H. Whitehead and M. Schreiber, "Current collectors for positive electrodes of lithium-based batteries," Journal of the Electrochemical Society, 152(11)A2105-A2113 (2005)). By way of further example, in one embodiment, the cathode current collector 204 includes gold or an alloy thereof, such as gold silicide. By way of further example, in one embodiment, the cathode current collector 204 includes nickel or an alloy thereof, such as nickel silicide.

[0052] The cathode active material layer 106 can be an intercalation-type chemically active material, a conversion chemically active material, or a combination thereof.

[0053] Exemplary conversion chemical materials useful in the present disclosure include S (or the lithiated state LiS), LiF, Fe, Cu, Ni, FeF, FeO d F 3.2d , FeF3, CoF3, CoF2, CuF2, NiF2 (where 0≦d≦0.5), and the like.

[0054] The exemplary cathode active material layer 106 may also include any of a wide range of intercalation-type cathode active materials. For example, in the case of a lithium-ion battery, the cathode active material may include a cathode active material selected from transition metal oxides, transition metal sulfides, transition metal nitrides, lithium transition metal oxides, and lithium transition metal sulfides, with lithium transition metal nitrides being selectively used. The transition metal elements of these transition metal oxides, transition metal sulfides, and transition metal nitrides may include metal elements having d-shells or f-shells. Specific examples of such metal elements may include Sc, Y, lanthanides, actinides, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pb, Pt, Cu, Ag, and Au. Additional cathode active materials include LiCoO2, LiNi 0.5 Mn 1.5 O4, Li(Ni x Co y Al z )O2, LiFePO4, Li2MnO4, V2O5, molybdenum oxysulfide, phosphates, silicates, vanadates, sulfur, sulfur compounds, oxygen (air), Li(Ni x Mn y Co z )O2, and combinations thereof.

[0055] Generally, the cathode active material layer 106 has a thickness of at least about 20 μm. For example, in one embodiment, the cathode active material layer 106 has a thickness of at least about 40 μm. By way of further example, in one such embodiment, the cathode active material layer 106 has a thickness of at least about 60 μm. By way of further example, in one such embodiment, the cathode active material layer 106 has a thickness of at least about 100 μm. Typically, the cathode active material layer 106 has a thickness of less than about 90 μm or less than about 70 μm.

[0056] FIG. 3 illustrates one of the cathode structures 206 of FIG. 2. Each cathode structure 206 has a longitudinal axis (A CE ) measured along the length (L CE ), width (W CE ), and length L CE and width WCE The height (H CE ).

[0057] The total length L of the cathode structure 206 CE will vary depending on the secondary battery 100 and its intended use. In general, however, each cathode structure 206 typically has a length L in the range of about 5 millimeters (mm) to about 500 mm. CE For example, in one such embodiment, each cathode structure 206 has a length L of about 10 mm to about 250 mm. CE By way of further example, in one such embodiment, each cathode structure 206 has a length L of about 25 mm to about 100 mm. CE According to one embodiment, the cathode structure 206 includes one or more first electrode members having a first length and one or more second electrode members having a second length different from the first length. In yet another embodiment, the different lengths of the one or more first electrode members and the one or more second electrode members may be selected to conform to a predetermined shape of the electrode assembly, such as an electrode assembly shape having different lengths along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0058] Width W of cathode structure 206 CE W also varies depending on the secondary battery 100 and its intended use. In general, however, the cathode structure 206 typically has a width W in the range of about 0.01 mm to 2.5 mm. CE For example, in one embodiment, each cathode structure 206 has a width W CE By way of further example, in one embodiment, the width W of each cathode structure 206 is in the range of about 0.025 mm to about 2 mm. CEis in the range of about 0.05 mm to about 1 mm. According to one embodiment, the cathode structure 206 includes one or more first electrode members having a first width and one or more second electrode members having a second width different from the first width. In yet another embodiment, the different widths of the one or more first electrode members and the one or more second electrode members may be selected to conform to a predetermined shape of the secondary battery 100, such as an assembly having different widths along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0059] Height H of cathode structure 206 CE will vary depending on the secondary battery 100 and its intended use. In general, however, the cathode structure 206 will typically have a height H CE For example, in one embodiment, each cathode structure 206 has a height H CE By way of further example, in one embodiment, the height H of each cathode structure 206 is in the range of about 0.05 mm to about 5 mm. CE is in the range of about 0.1 mm to about 1 mm. According to one embodiment, the cathode structure 206 includes one or more first cathode members having a first height and one or more second cathode members having a second height different from the first height. In yet another embodiment, the different heights of the one or more first cathode members and the one or more second cathode members may be selected to conform to a predetermined shape of the secondary battery 100, such as a shape having different heights along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0060] Generally, each cathode structure 206 has a width W CE and its height H CE Length L substantially larger than CE For example, in one embodiment, for each cathode structure 206, W CE and H CE L for each CE The ratio of L CEAgainst W CE The ratio of L to L is at least 5:1, CE Against H CE and the ratio of W to W is at least 5:1, respectively. CE and H CE L for each CE is at least 10:1 for each cathode structure 206. By way of further example, in one embodiment, W CE and H CE L for each CE is at least 15:1 for each cathode structure 206. By way of further example, in one embodiment, W CE and H CE L for each CE is at least 20:1 for each cathode structure 206.

[0061] In one embodiment, the width W of the cathode structure 206 CE Height H CE and H are each at least 0.4:1. CE Against W CE is at least 2:1, respectively, for each cathode structure 206. By way of further example, in one embodiment, H CE Against W CE is at least 10:1, respectively, for each cathode structure 206. By way of further example, in one embodiment, H CE Against W CE The ratio of H is at least 20:1 for each cathode structure 206, respectively. CE Against W CE The ratio of H is generally at least 1,000:1, respectively, for each cathode structure 206. For example, in one embodiment, CE Against W CE is less than 500:1, respectively, for each cathode structure 206. By way of further example, in one embodiment, H CE W CE and H are each less than 100:1. CE W CEand H are each less than 10:1. CE Against W CE is in the range of about 2:1 to about 100:1 for each cathode structure 206, respectively.

[0062] Anode structure and materials 2, the anode current collector 202 in the unit cell 200 may comprise a conductive material such as copper, carbon, nickel, stainless steel, cobalt, titanium, and tungsten, and alloys thereof, or any other material suitable as an anode current collector layer. Generally, the anode current collector 202 has a thickness of at least about 10 3 For example, in one such embodiment, the anode current collector 202 has a conductivity of at least about 10 4 By way of further example, in one such embodiment, the anode current collector 202 has a conductivity of at least about 10 5 It has a conductivity in Siemens / cm.

[0063] In general, the anode active material layer 104 in the unit cell 200 may be selected from the group consisting of: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements; (c) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zinc (Zn), Al, Ti, Ni, Co, or Cd with other elements; (d) oxides, carbides, nitrides, sulfides, phosphides, selenides and tellurides of Al, Al, Ti, Fe, Ni, Co, V, or Cd, and mixtures, composites, or lithium-containing composites thereof; (d) salts and hydroxides of Sn; (e) lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxides, lithium transition metal oxides, ZnCo2O4; (f) particles of graphite and carbon; (g) lithium metal; and (h) combinations thereof.

[0064] Exemplary anode active material layer 104 includes graphite and soft or hard carbon, or carbon materials such as graphene (e.g., single-walled or multi-walled carbon nanotubes), or any of a range of metals, metalloids, alloys, oxides, nitrides, and compounds that can intercalate or alloy with lithium. Specific examples of metals or metalloids that can comprise the anode material include graphite, tin, lead, magnesium, aluminum, boron, gallium, silicon, Si / C composites, Si / graphite blends, silicon oxide (SiOx), porous Si, intermetallic Si alloys, indium, zirconium, germanium, bismuth, cadmium, antimony, silver, zinc, arsenic, hafnium, yttrium, lithium, sodium, graphite, carbon, lithium titanate, palladium, and mixtures thereof. In one exemplary embodiment, the anode active material includes aluminum, tin, or silicon, or oxides thereof, nitrides thereof, fluorides thereof, or other alloys thereof. In another exemplary embodiment, the anode active material layer 104 includes silicon or an alloy or oxide thereof.

[0065] In one embodiment, the anode active material layer 104 is microstructured to provide a significant void volume fraction to accommodate volume expansion and contraction as lithium ions (or other carrier ions) are incorporated into or exit the anode active material layer 104 during the charge and discharge process of the secondary battery 100. In general, the void volume fraction of the (each of) the anode active material layer 104 is at least 0.1. Typically, however, the void volume fraction of the (each of) the anode active material layer 104 is 0.8 or less. For example, in one embodiment, the void volume fraction of the (each of) the anode active material layer 104 is between about 0.15 and about 0.75. As a further example, in one embodiment, the void volume fraction of the (each of) the anode active material layer 104 is between about 0.2 and about 0.7. By way of further example, in one embodiment, the void volume fraction of (each of) the anode active material layers 104 is between about 0.25 and about 0.6.

[0066] Depending on the composition of the microstructured anode active material layer 104 and the method of their formation, the microstructured anode active material layer 104 may comprise a macroporous, microporous, or mesoporous material layer, or a combination thereof, such as a combination of mesoporous and macroporous. Microporous materials are typically characterized by pore dimensions less than 10 nanometers (nm), wall dimensions less than 10 nm, pore depths between 1 μm and 50 μm, and a pore morphology generally characterized by a "spongy" irregular appearance, non-smooth walls, and branched pores. Mesoporous materials are typically characterized by pore dimensions between 10 nm and 50 nm, wall dimensions between 10 nm and 50 nm, pore depths between 1 μm and 100 μm, and a pore morphology generally characterized by more or less well-defined branched or dendritic pores. Macroporous materials are typically characterized by pore dimensions greater than 50 nm, wall dimensions greater than 50 nm, pore depths between 1 μm and 500 μm, and pore morphologies that can be linear, branched, or dendritic, and smooth or rough-walled. In addition, the void volume can include open or closed porosity, or a combination thereof. In one embodiment, the void volume includes open porosity, i.e., the anode active material layer 104 includes porosity at the sides of the anode active material layer that has openings through which lithium ions (or other carrier ions) can enter or exit. For example, lithium ions can enter the anode active material layer 104 through the pore openings after leaving the cathode active material layer 106. In another embodiment, the void volume includes closed porosity, i.e., the anode active material layer 104 includes porosity that is enclosed. In general, open porosity can provide a larger interfacial surface area for carrier ions, while closed porosity tends to be less susceptible to SEI formation, each providing room for expansion of anode active material layer 104 upon the ingress of carrier ions. Thus, in certain embodiments, it is preferred that anode active material layer 104 include a combination of open and closed porosity.

[0067] In one embodiment, the anode active material layer 104 comprises porous aluminum, tin, or silicon, or alloys, oxides, or nitrides thereof. The porous silicon layer may be formed, for example, by anodization, by etching (e.g., by depositing a precious metal such as gold, platinum, silver, or gold / palladium on the surface of single crystal silicon and etching the surface with a mixture of hydrofluoric acid and hydrogen peroxide), or by other methods known in the art, such as patterned chemical etching. In addition, the porous anode active material layer 104 generally has a porosity of at least about 0.1 but less than 0.8, and a thickness of about 1 μm to about 100 μm. For example, in one embodiment, the anode active material layer 104 comprises porous silicon, has a thickness of about 5 μm to about 100 μm, and has a porosity of about 0.15 to about 0.75. By way of further example, in one embodiment, the anode active material layer 104 comprises porous silicon, has a thickness of about 10 μm to about 80 μm, and has a porosity of about 0.15 to about 0.7. By way of further example, in one such embodiment, the anode active material layer 104 comprises porous silicon, has a thickness of about 20 μm to about 50 μm, and has a porosity of about 0.25 to about 0.6. By way of further example, in one such embodiment, the anode active material layer 104 comprises a porous silicon alloy (such as nickel silicide), has a thickness of about 5 μm to about 100 μm, and has a porosity of about 0.15 to about 0.75.

[0068] In another embodiment, the anode active material layer 104 comprises fibers of aluminum, tin, or silicon, or alloys thereof. The individual fibers may have a diameter (thickness dimension) of about 5 nm to about 10,000 nm and a length that generally corresponds to the thickness of the anode active material layer 104. The silicon fibers (nanowires) may be formed by other techniques known in the art, such as, for example, chemical vapor deposition or vapor-liquid-solid (VLS) growth and solid-liquid-solid (SLS) growth. In addition, the anode active material layer 104 generally has a porosity of at least about 0.1 but less than 0.8, and a thickness of about 1 μm to about 200 μm. For example, in one embodiment, the anode active material layer 104 comprises silicon nanowires, has a thickness of about 5 μm to about 100 μm, and a porosity of about 0.15 to about 0.75. By way of further example, in one embodiment, anode active material layer 104 comprises silicon nanowires, has a thickness of about 10 μm to about 80 μm, and a porosity of about 0.15 to about 0.7. By way of further example, in one such embodiment, anode active material layer 104 comprises silicon nanowires, has a thickness of about 20 μm to about 50 μm, and a porosity of about 0.25 to about 0.6. By way of further example, in one such embodiment, anode active material layer 104 comprises silicon alloy (such as nickel silicide) nanowires, has a thickness of about 5 μm to about 100 μm, and a porosity of about 0.15 to about 0.75.

[0069] In yet another embodiment, the anode active material layer 104 is coated with a particulate lithium material selected from the group consisting of stabilized lithium metal particles, such as lithium carbonate stabilized lithium metal powder, lithium silicate stabilized lithium metal powder, or other sources of stabilized lithium metal powder or ink. The particulate lithium material is coated with a concentration of about 0.05 mg / cm. 2 ~5mg / cm 2 , for example, about 0.1 mg / cm 2 ~4mg / cm 2 , or even about 0.5 mg / cm 2 ~3mg / cm 2 The lithium particulate material may be applied onto the anode active material layer 104 by spraying, packing, or otherwise disposing on the anode active material layer 104 at a loading of about 100 μm.50 The average particle size (D) can be from 5 μm to 200 μm, for example, from about 10 μm to 100 μm, from 20 μm to 80 μm, or even from about 30 μm to 50 μm. 50 ) can be defined as the particle size corresponding to 50% on the cumulative volume-based particle size distribution curve. 50 ) can be measured, for example, using laser diffraction methods.

[0070] In one embodiment, the anode current collector 202 has a conductivity that is substantially greater than the conductivity of its associated anode active material layer 104. For example, in one embodiment, the ratio of the conductivity of the anode current collector 202 to the conductivity of the anode active material layer 104 is at least 100:1 when there is an applied current to store energy in the secondary battery 100 or an applied load to discharge the secondary battery 100. By way of further example, in some embodiments, the ratio of the conductivity of the anode current collector 202 to the conductivity of the anode active material layer 104 is at least 500:1 when there is an applied current to store energy in the secondary battery 100 or an applied load to discharge the secondary battery 100. By way of further example, in some embodiments, the ratio of the conductivity of the anode current collector 202 to the conductivity of the anode active material layer 104 is at least 1000:1 when there is an applied current to store energy in the secondary battery 100 or an applied load to discharge the secondary battery 100. By way of further example, in some embodiments, the ratio of the conductivity of the anode current collector 202 to the conductivity of the anode active material layer 104 is at least 5000:1 when there is an applied current to store energy in the secondary battery 100 or an applied load to discharge the secondary battery 100. By way of further example, in some embodiments, the ratio of the conductivity of the anode current collector 202 to the conductivity of the anode active material layer 104 is at least 10,000:1 when there is an applied current to store energy in the secondary battery 100 or an applied load to discharge the secondary battery 100.

[0071] FIG. 4 illustrates one of the anode structures 207 of FIG. 2 in an exemplary embodiment. Each anode structure 207 is aligned along the longitudinal axis (AE ) measured along the length (L E ), width (W E ), and length L E and width W E The height (H E ).

[0072] Length L of anode structure 207 E will vary depending on the secondary battery 100 and its intended use. In general, however, the anode structure 207 typically has a length L in the range of about 5 millimeters (mm) to about 500 mm. E For example, in one such embodiment, the anode structure 207 has a length L of about 10 mm to about 250 mm. E By way of further example, in one such embodiment, the anode structure 207 has a length L of about 25 mm to about 100 mm. E According to one embodiment, the anode structure 207 includes one or more first electrode members having a first length and one or more second electrode members having a second length different from the first length. In yet another embodiment, the different lengths of the one or more first electrode members and the one or more second electrode members may be selected to conform to a predetermined shape of the secondary battery 100, such as a shape having different lengths along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0073] Width W of anode structure 207 E W also varies depending on the secondary battery 100 and its intended use. In general, however, each anode structure 207 typically has a width W E For example, in one embodiment, each anode structure 207 has a width W E By way of further example, in one embodiment, the width W of each anode structure 207 is in the range of about 0.025 mm to about 2 mm. Eis in the range of about 0.05 mm to about 1 mm. According to one embodiment, the anode structure 207 includes one or more first electrode members having a first width and one or more second electrode members having a second width different from the first width. In yet another embodiment, the different widths of the one or more first electrode members and the one or more second electrode members may be selected to conform to a predetermined shape of the secondary battery 100, such as a shape having different widths along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0074] Height H of anode structure 207 E will vary depending on the secondary battery 100 and its intended use. In general, however, the anode structure 207 will typically have a height H E For example, in one embodiment, each anode structure 207 has a height H E By way of further example, in one embodiment, the height H of each anode structure 207 is in the range of about 0.05 mm to about 5 mm. E is in the range of about 0.1 mm to about 1 mm. According to one embodiment, the anode structure 207 includes one or more first electrode members having a first height and one or more second electrode members having a second height different from the first height. In yet another embodiment, the different heights for the one or more first electrode members and the one or more second electrode members may be selected to conform to a predetermined shape of the secondary battery 100, such as a shape having different heights along one or more of the longitudinal and / or lateral axes, and / or to provide predetermined performance characteristics of the secondary battery 100.

[0075] Generally, each anode structure 207 has a width W E and height H E A length L substantially larger than each of E For example, in one embodiment, for each anode structure 207, W E and H E L for each E The ratio of L E Against WE The ratio of L to L is at least 5:1, E Against H E and the ratio of W to W is at least 5:1, respectively. E and H E L for each E is at least 10:1. By way of further example, in one embodiment, W E and H E L for each E is at least 15:1. By way of further example, in one embodiment, W E and H E L for each E is at least 20:1 for each anode structure 207.

[0076] In one embodiment, the width W of the anode structure 207 E Height H E and H are each at least 0.4:1. E Against W E is at least 2:1, respectively, for each anode structure 207. By way of further example, in one embodiment, H E W E and H are each at least 10:1. E W E The ratio of H to H is at least 20:1, respectively. E Against W E The ratio of H is generally less than 1,000:1, respectively. For example, in one embodiment, E W E and H are each less than 500:1. E W E and H are each less than 100:1. E W E and H are each less than 10:1. E W Eto ranges from about 2:1 to about 100:1 for each anode structure 207, respectively.

[0077] Separator structure, separator material, and electrolyte Referring again to FIG. 2, separator layer(s) 108 separate the cathode structure 206 from the anode structure 207. The separator layer 108 is made of an electrically insulating but ionically permeable separator material. The separator layer 108 is adapted to electrically insulate each member of the plurality of cathode structures 206 from each member of the plurality of anode structures 207. Each separator layer 108 will typically comprise a microporous separator material that can be permeated with a non-aqueous electrolyte. For example, in one embodiment, the microporous separator material comprises pores having a diameter of at least 50 angstroms (Å), more typically in the range of about 2,500 Å, and a porosity in the range of about 25% to about 75%, more typically in the range of about 35% to 55%.

[0078] Generally, the separator layers 108 each have a thickness of at least about 4 μm. For example, in one embodiment, the separator layers 108 have a thickness of at least about 8 μm. By way of further example, in one such embodiment, the separator layers 108 have a thickness of at least about 12 μm. By way of further example, in one such embodiment, the separator layers 108 have a thickness of at least about 15 μm. In some embodiments, the separator layers 108 have a thickness of up to 25 μm, up to 50 μm, or any other suitable thickness. Typically, however, the separator layers 108 have a thickness of less than about 12 μm or less than about 10 μm.

[0079] In general, the material of the separator layer 108 can be selected from a wide range of materials capable of conducting carrier ions between the anode active material layer 104 and the cathode active material layer 106 of the unit cell 200. For example, the separator layer 108 can include a microporous separator material capable of being permeated with a liquid non-aqueous electrolyte. Alternatively, the separator layer 108 can include a gel or solid electrolyte capable of conducting carrier ions between the anode active material layer 104 and the cathode active material layer 106 of the unit cell 200.

[0080] In one embodiment, the separator layer 108 may include a polymer-based electrolyte. Exemplary polymer electrolytes include PEO-based polymer electrolytes and polymer-ceramic composite electrolytes.

[0081] In another embodiment, the separator layer 108 may include an oxide-based electrolyte. Exemplary oxide-based electrolytes include lithium lanthanum titanate (Li 0.34 La 0.56 TiO3), Al-doped lithium lanthanum zirconate (Li 6.24 La3Zr2Al 0.24 O 11.98 ), Ta-doped lithium lanthanum zirconate (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 ), and lithium aluminum titanium phosphate (Li 1.4 Al 0.4 Ti 1.6 (PO4)3).

[0082] In another embodiment, the separator layer 108 may include a solid electrolyte. An exemplary solid electrolyte includes lithium tin phosphate (Li 10 SnP2S 12 ), lithium phosphorus sulfide (β-Li3PS4), and lithium phosphorus sulfide iodide (Li6PS5Cl 0.9 I 0.1 ) and other sulfide-based electrolytes.

[0083] In some embodiments, the separator layer 108 may include a solid lithium-ion conducting ceramic, such as a lithium-filled garnet.

[0084] In one embodiment, the separator layer 108 comprises a microporous separator material including a particulate material and a binder, the microporous separator material having a porosity of at least about 20% by volume. The pores of the microporous separator material have a diameter of at least 50 Å, typically in the range of about 250 Å to about 2,500 Å. The microporous separator material typically has a porosity of less than about 75%. In one embodiment, the microporous separator material has a porosity of at least about 25% by volume. In one embodiment, the microporous separator material has a porosity of about 35 to 55%.

[0085] Binders for microporous separator materials can be selected from a wide range of inorganic or polymeric materials. For example, in one embodiment, the binder is an organic material selected from the group consisting of silicates, phosphates, aluminates, aluminosilicates, and hydroxides such as magnesium hydroxide, calcium hydroxide, etc. For example, in one embodiment, the binder is a fluoropolymer derived from monomers containing vinylidene fluoride, hexafluoropropylene, tetrafluoropropene, etc. In another embodiment, the binder is a polyolefin such as polyethylene, polypropylene, or polybutene having any of a variety of molecular weight and density ranges. In another embodiment, the binder is selected from the group consisting of ethylene-diene-propene terpolymer, polystyrene, polymethyl methacrylate, polyethylene glycol, polyvinyl acetate, polyvinyl butyral, polyacetal, and polyethylene glycol diacrylate. In another embodiment, the binder is selected from the group consisting of methyl cellulose, carboxymethyl cellulose, styrene rubber, butadiene rubber, styrene butadiene rubber, isoprene rubber, polyacrylamide, polyvinyl ether, polyacrylic acid, polymethacrylic acid, and polyethylene oxide. In another embodiment, the binder is selected from the group consisting of acrylates, styrenes, epoxies, and silicones, hi another embodiment, the binder is a copolymer or blend of two or more of the foregoing polymers.

[0086] The particulate material included in the microporous separator material may also be selected from a wide range of materials. Generally, such materials have relatively low electronic and ionic conductivity at operating temperatures and do not corrode under the operating voltages of the battery electrodes or current collectors that contact the microporous separator material. For example, in one embodiment, the particulate material is in the range of 1×10 -4 By way of further example, in one embodiment, the particulate material has a conductivity for carrier ions (e.g., lithium) of less than 1×10 -5 By way of further example, in one embodiment, the particulate material has a carrier ion conductivity of less than 1×10 -6The conductive material has a carrier ion conductivity of less than 10 ... In one embodiment, the particulate material has an average particle size of about 20 nm to 2 μm, more typically 200 nm to 1.5 μm, In one embodiment, the particulate material has an average particle size of about 500 nm to 1 μm.

[0087] In alternative embodiments, the particulate materials comprised by the microporous separator material may be bound by techniques such as sintering, bonding, curing, etc., while maintaining a desired porosity for electrolyte infiltration to provide ionic conductivity for the functioning of the battery.

[0088] In secondary battery 100 (see FIG. 1), the microporous separator material of separator layer 108 is infiltrated with a non-aqueous electrolyte suitable for use as a secondary battery electrolyte. Typically, the non-aqueous electrolyte comprises a lithium salt and / or mixture of salts dissolved in an organic solvent and / or solvent mixture. Exemplary lithium salts include inorganic lithium salts such as LiClO4, LiBF4, LiPF6, LiAsF6, LiCl, and LiBr, LiB(C6H5)4, LiN(SO2CF3)2, LiN(SO2CF3)3, LiNSO2CF3, LiNSO2CF5, LiNSO2C4F9, LiNSO2C5F 11 , LiNSO2C6F 13 , and LiNSO2C7F 15The organic lithium salts include organic lithium salts such as those mentioned above. Examples of organic solvents that dissolve lithium salts include cyclic esters, chain esters, cyclic ethers, and chain ethers. Specific examples of cyclic esters include propylene carbonate, butylene carbonate, γ-butyrolactone, vinylene carbonate, 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone. Specific examples of chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate, butyl propyl carbonate, alkyl propionate, dialkyl malonate, and alkyl acetate. Specific examples of cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, dialkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, and 1,4-dioxolane.Specific examples of chain ethers include 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

[0089] Additional Embodiments of the Disclosure When a secondary battery is assembled, the amount of carrier ions available for circulation between the anode and cathode is often initially provided at the cathode because cathode active materials such as lithium cobalt oxide are relatively stable in ambient air (e.g., they resist oxidation) compared to lithiated anode materials such as lithiated graphite. When the secondary battery is first charged, carrier ions are extracted from the cathode and introduced into the anode. As a result, the anode potential drops significantly (towards the potential of the carrier ions) and the cathode potential rises (to become more positive). These potential changes can cause parasitic reactions at both the cathode and anode, but sometimes more severely at the anode. For example, decomposition products containing lithium (or other carrier ions) and electrolyte components, known as solid electrolyte interfaces (SEIs), can easily form on the surface of carbon anodes. These surfaces or coating layers are carrier ion conductors and establish ionic bonds between the anode and the electrolyte, preventing the reaction from proceeding further.

[0090] Although the formation of the SEI layer is desirable for the stability of the half-cell system including the anode and electrolyte, a portion of the carrier ions introduced into the cell through the cathode are irreversibly bound and therefore removed from the cycling operation, i.e., from the capacity available to the user. As a result, during the initial discharge, fewer carrier ions are transferred back from the anode to the cathode than were initially provided by the cathode during the initial charging operation, resulting in irreversible capacity loss. During each subsequent charge and discharge cycle, the capacity loss resulting from mechanical and / or electrical degradation to the anode and / or cathode tends to be much less per cycle, but even the relatively small carrier ion losses per cycle contribute significantly to the reduction in energy density and cycle life as the battery ages. In addition, chemical and electrochemical degradation can also occur on the electrodes, causing capacity loss. To compensate for the formation of the SEI (or another carrier ion consumption mechanism, such as mechanical and / or electrical degradation of the negative electrode), additional or supplemental carrier ions can be provided from an auxiliary electrode after the formation of the battery.

[0091] In general, the positive electrode 208 of the secondary battery 100 (e.g., the population of negative electrode structures 206 in the secondary battery 100) preferably has a reversible coulombic capacity that matches the discharge capacity of the negative electrode 209 (e.g., the population of anode structures 207 in the secondary battery 100). Stated another way, the positive electrode 208 of the secondary battery 100 is sized to have a reversible coulombic capacity that corresponds to the discharge capacity of the negative electrode 209, which is a function of the end-of-discharge voltage of the negative electrode 209.

[0092] In some embodiments, the negative electrode 209 of the secondary battery 100 (e.g., the collective collection of positive electrode structures 207 in the secondary battery 100) is designed to have a reversible coulombic capacity that exceeds the reversible coulombic capacity of the positive electrode 208. For example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208, respectively, is at least 1.2:1. As a further example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208, respectively, is at least 1.3:1. As a further example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208, respectively, is at least 2:1. As a further example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208, respectively, is at least 3:1. As a further example, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208 is at least 4:1, respectively. As a further example, the ratio of the reversible coulombic capacity of the negative electrode 209 to the reversible coulombic capacity of the positive electrode 208 is at least 5:1, respectively. Advantageously, the excess coulombic capacity of the negative electrode 209 provides a source of positive electrode active material, allowing the secondary battery 100 to operate reversibly within a certain voltage that inhibits the formation of crystalline phases (which incorporate carrier ions) on the negative electrode 209 that would reduce the cycle life of the negative electrode 209 as a result of cycling.

[0093] As mentioned above, the formation of the SEI during the initial charge / discharge cycles reduces the amount of carrier ions available for reversible cycling. Mechanical and / or electrical degradation of the negative electrode 209 during cycling of the secondary battery 100 may further reduce the amount of carrier ions available for reversible cycling. Therefore, to compensate for the formation of the SEI (or another carrier ion consumption mechanism such as mechanical and / or electrical degradation of the negative electrode), additional or supplemental carrier ions can be provided from an auxiliary electrode after formation of the secondary battery 100. In an embodiment of the present disclosure, the auxiliary electrode is used to electrochemically transfer additional carrier ions to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100 during and / or after formation. In one embodiment, the auxiliary electrode is removed after transferring additional carrier ions to the secondary battery 100 to improve the energy density of the final form of the secondary battery.

[0094] FIG. 5 is a perspective view of an exemplary embodiment of a buffer system 500, and FIG. 6 is an exploded view of the buffer system 500. In general, the buffer system 500 can be temporarily assembled during or after the initial formation of the secondary battery 100, and the buffer system 500 is used to introduce additional carrier ions to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100 using an auxiliary electrode 502 (see FIG. 6). In this embodiment, the buffer system 500 includes an enclosure 504 that encapsulates the auxiliary electrode 502 (see FIG. 6) and the secondary battery 100 within the periphery 506 of the enclosure 504. In FIG. 5, the electrical terminals 124, 125 of the secondary battery 100 and segments of the conductive tab 508-1 extend from the periphery 506 of the enclosure 504 and provide electrical connections to the auxiliary electrode 502 and the secondary battery 100. In this embodiment, the enclosure 504 includes a first enclosure layer 510 and a second enclosure layer 511 joined together to form the enclosure 504 .

[0095] 6, the first enclosure layer 510 has a perimeter 512 and the second enclosure layer 511 has a perimeter 513. Each of the enclosure layers 510, 511 may include a flexible or semi-flexible material, such as aluminum, a polymer, a thin flexible metal, or the like. In one embodiment, one or more of the enclosure layers 510, 511 includes a multi-layer aluminum polymer material, plastic, or the like. In another embodiment, one or more of the enclosure layers 510, 511 includes a polymer material laminated on a metal substrate, such as aluminum. In one embodiment, the first enclosure layer 510 includes a pouch 514 (e.g., a recess) that is sized and shaped to match the exterior size and shape of the secondary battery 100.

[0096] The auxiliary electrode 502 partially surrounds the secondary battery 100 in the buffer system 500 and includes a source of carrier ions to replenish the lost energy capability of the secondary battery 100 after formation (i.e., to compensate for the loss of carrier ions during the formation of the SEI and other carrier ion losses during the first charge and / or discharge cycle of the secondary battery 100). In some embodiments, the auxiliary electrode 502 may include a foil of carrier ions in metallic form (e.g., a foil of lithium, magnesium, or aluminum) or any of the aforementioned materials used for the cathode active material layer 106 and / or anode active material layer 104 (see FIG. 2) in a carrier ion-containing form. For example, the auxiliary electrode 502 may include lithiated silicon or a lithiated silicon alloy. When the buffer system 500 is assembled, the combination of the auxiliary electrode 502, which may be referred to as an auxiliary subassembly 516 (see FIG. 6), and the secondary battery 100 is inserted into the pouch 514, and the enclosure layers 510, 511 are sealed together to form the buffer system 500 as depicted in FIG. 5. Specific details of the assembly process for the buffer system 500 and how the buffer system 500 is used during the carrier ion transfer process to the secondary battery 100 are described in more detail below. The auxiliary electrode 502 in this embodiment includes a conductive tab 508, which may be segmented, for example, for ease of manufacturing, into a conductive tab 508-2 that is covered by the enclosure 504 and a conductive tab 508-1 that is partially exposed by the enclosure, as depicted in FIG. 5.

[0097] FIG. 7 is a perspective view of an auxiliary electrode 502 according to an embodiment of the present invention, and FIG. 8 is an exploded perspective view of the auxiliary electrode. Referring to FIG. 7, the auxiliary electrode 502 includes a separator 702 covering a conductive layer 704 and a carrier ion supply layer 706. When the auxiliary electrode 502 is formed into the shape depicted in FIG. 6, the carrier ion supply layer 706 is disposed adjacent to the main surfaces 126, 127 (see FIG. 1) of the secondary battery 100, and the separator 702 insulates the casing 116 of the secondary battery 100 from the conductive layer 704 and the carrier ion supply layer 706. The separator 702 includes an electrolyte, which facilitates the movement of carrier ions from the carrier ion supply layer 706 to the secondary battery 100 during the buffering process.

[0098] 8, the auxiliary electrode 502 includes, from bottom to top in FIG. 8, a collection of separator 702, conductive layer 704, and carrier ion supply layer 706. The auxiliary electrode 502 in this embodiment further includes a conductive tab 508-2, which is conductive and electrically coupled to the conductive layer 704. The conductive tab 508-2 provides an electrical connection to the auxiliary electrode 502. In general, the auxiliary electrode 502 is used during a buffer process to transfer carrier ions from the carrier ion supply layer 706 to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100 during or after formation of the secondary battery 100.

[0099] The separator 702 may include any of the materials described above with respect to the separator layer 108 of the secondary battery 100. The separator 702 may be impregnated with an electrolyte that provides a medium for conducting carrier ions from the carrier ion supply layer 706 to the positive electrode 208 of the secondary battery 100 and / or the negative electrode 209 of the secondary battery. The electrolyte may include any of the materials described above with respect to the secondary battery 100.

[0100] The separator 702 in this embodiment includes a first surface 802 and a second surface 803 opposite the first surface 802. The surfaces 802, 803 of the separator 702 form the main surface of the separator 702 and are disposed in the XY plane of FIG. 8. The separator 702 in this embodiment has a width 804 extending in the direction of the Y axis. The separator 702 in this embodiment is segmented in the width 804 into a first portion 805 and a second portion 806. In some embodiments, the separator 702 can include a first separator layer 702-1 corresponding to the first portion 805 and a second separator layer 702-2 corresponding to the second portion 806.

[0101] In one embodiment, the width 804 of the separator 702 is about 34 mm. In other embodiments, the width 804 of the separator is about 30 mm, about 35 mm, or another suitable value. In some embodiments, the width 804 of the separator 702 is within a range of values ​​from about 10 mm to about 200 mm, or any other suitable range that enables the separator 702 to function as described herein.

[0102] The separator 702, in one embodiment, has a length 808 that extends in the direction of the X-axis. In one embodiment, the length 808 of the separator 702 is about 72 mm. In other embodiments, the length 808 of the separator 702 is about 65 mm, about 70 mm, about 75 mm, or any other suitable value that enables the separator 702 to function as described herein. In some embodiments, the length 808 of the separator 702 is within a range of values ​​from about 30 mm to about 200 mm, or any other suitable range of values ​​that enables the separator 702 to function as described herein.

[0103] In one embodiment, the separator 702 has a thickness 810 extending in the direction of the Z-axis. Generally, the thickness 810 is the distance from the first surface 802 of the separator 702 to (and including) the second surface 803 of the separator. In one embodiment, the thickness 810 of the separator 702 is about 0.025 mm. In other embodiments, the thickness 810 of the separator 702 is about 0.015 mm, about 0.02 mm, about 0.03 mm, about 0.035 mm, or some other suitable value. In some embodiments, the thickness 810 of the separator 702 is within a range of values ​​from about 0.01 mm to about 1.0 mm, or some other suitable range of values ​​that enables the separator 702 to function as described herein.

[0104] The conductive layer 704 is electrically conductive and may include a metal, a metallized film, an insulating base material to which a conductive material is applied, or some other type of conductive material. In some embodiments, the conductive layer 704 includes copper. In other embodiments, the conductive layer 704 includes aluminum or another metal. In this embodiment, the conductive layer 704 is electrically coupled to a conductive tab 508-2, which is also electrically conductive. The conductive tab 508-2 has a first end 812 disposed proximate to the conductive layer 704 and a second end 813 disposed distally of the conductive layer 704 opposite the first end 812. The first end 812 of the conductive tab 508-2 is electrically coupled to the conductive layer 704. In some embodiments, the first end 812 of the conductive tab 508-2 is spot welded to the conductive layer 704. In other embodiments, the first end 812 of the conductive tab 508-2 is soldered to the conductive layer 704. In general, the conductive tab 508-2 may be affixed to the conductive layer 704 at the first end 812 using any suitable means that ensures a mechanical and electrical connection to the conductive layer. The conductive tab 508-2 may comprise any type of conductive material as desired. In one embodiment, the conductive tab 508-2 comprises a metal. In these embodiments, the conductive tab 508-2 may comprise nickel, copper, aluminum, or other suitable metal or metal alloy that enables the conductive tab 508-2 to function as described herein.

[0105] The conductive layer 704 in this embodiment includes a first surface 814 and a second surface 815 opposite the first surface 814. The surfaces 814, 815 of the conductive layer 704 form the major surfaces of the conductive layer 704 and are disposed in the XY plane of FIG. 8. The conductive layer 704 in this embodiment has a width 816 that extends in the direction of the Y axis. In one embodiment, the width 816 of the conductive layer 704 is about 15 mm. In other embodiments, the width 816 of the conductive layer 704 is about 10 mm, about 20 mm, or any other suitable value that enables the conductive layer 704 to function as described herein.

[0106] In some embodiments, the width 816 of the conductive layer 704 is within a range of values ​​from about 5 mm to about 100 mm, or any other suitable range of values ​​that enables the conductive layer 704 to function as described herein. The first surface 814 of the conductive layer 704 in this embodiment is segmented into a first region 818-1 disposed proximate a first end 820 of the conductive layer 704, a second region 818-2 disposed proximate a second end 821 of the conductive layer 704, and a third region 818-3 disposed between the first region 818-1 and the second region 818-2.

[0107] The conductive layer 704 has a length 822 that extends in the direction of the X-axis. In one embodiment, the length 822 of the conductive layer 704 is about 70 mm. In other embodiments, the length 822 of the conductive layer 704 is about 60 mm, about 65 mm, about 75 mm, or some other suitable value that enables the conductive layer 704 to function as described herein. In some embodiments, the length 822 of the conductive layer 704 is within a range of values ​​from about 30 mm to about 200 mm, or some other suitable range of values ​​that enables the conductive layer 704 to function as described herein.

[0108] The conductive layer 704 has a thickness 824 extending in the direction of the Z-axis. Generally, the thickness 824 is the distance from the first surface 814 of the conductive layer 704 to (and including) the second surface 815 of the conductive layer 704. In one embodiment, the thickness 824 of the conductive layer 704 is about 0.1 mm. In other embodiments, the thickness 824 of the conductive layer 704 is about 0.005 mm, about 0.15 mm, or about 0.2 mm. In some embodiments, the thickness 824 of the conductive layer 704 is within a range of values ​​from about 0.01 mm to about 1.0 mm, or any other suitable range of thicknesses that enables the conductive layer 704 to function as described herein.

[0109] In one embodiment, the carrier ion supply layer 706 including the population of carrier ion supply layers 706 includes any of the carrier ion containing materials described above that may be utilized to supply carrier ions to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100. The carrier ion supply layer 706 may include one or more sources of lithium ions, sodium ions, potassium ions, calcium ions, magnesium ions, and aluminum ions. In this embodiment, the carrier ion supply layer 706 is disposed in the first region 818-1 and the second region 818-2 of the conductive layer 704. In some embodiments, the carrier ion supply layer 706 is also disposed in the third region 818-3 of the conductive layer 704.

[0110] The carrier ion supply layer 706 in this embodiment has a first surface 826 and a second surface 827 opposite the first surface 826. The surfaces 826, 827 of the carrier ion supply layer 706 form the major surfaces of the carrier ion supply layer 706 and are disposed in the XY plane of FIG. 8. The carrier ion supply layer 706 in this embodiment has a width 828 extending in the direction of the Y axis. In one embodiment, the width 828 of the carrier ion supply layer 706 is about 15 mm. In other embodiments, the width 828 of the carrier ion supply layer 706 is about 10 mm, about 20 mm, or any other suitable value that enables the carrier ion supply layer 706 to function as described herein. In some embodiments, the width 828 of the carrier ion supply layer 706 is within a range of values ​​between about 5 mm and about 100 mm, or any other suitable range of values ​​that enables the carrier ion supply layer 706 to function as described herein.

[0111] The carrier ion supply layer 706, in one embodiment, has a length 830 extending in the direction of the X-axis. In one embodiment, the length 830 of the carrier ion supply layer 706 is about 23 mm. In other embodiments, the length 830 of the carrier ion supply layer 706 is about 15 mm, about 20 mm, about 25 mm, or any other suitable length that enables the carrier ion supply layer 706 to function as described herein. In some embodiments, the length 830 of the carrier ion supply layer 706 is within a range of values ​​from about 10 mm to about 100 mm, or any other suitable range of values ​​that enables the carrier ion supply layer 706 to function as described herein.

[0112] The carrier ion supply layer 706 has a thickness 832 extending in the direction of the Z-axis. Generally, the thickness 832 is the distance between a first surface 826 of the carrier ion supply layer 706 and a second surface 827 of the carrier ion supply layer 706. In one embodiment, the thickness 832 of the carrier ion supply layer 706 is about 0.13 mm. In other embodiments, the thickness 832 of the carrier ion supply layer 706 is about 0.005 mm, about 0.15 mm, or about 0.2 mm. In some embodiments, the thickness 832 of the carrier ion supply layer 706 is within a range of values ​​between about 0.01 mm and about 1.0 mm, or any other suitable value for the thickness 832 that enables the carrier ion supply layer 706 to function as described herein.

[0113] In this embodiment, the carrier ion supply layers 706 are separated from one another by a distance 834 that corresponds to the third region 818-3. In one embodiment, the distance 834 is about 23 mm. In other embodiments, the distance 834 is about 15 mm, about 20 mm, about 25 mm, or about 30 mm. In some embodiments, the distance 834 is within a range of values ​​from about 10 mm to about 50 mm, or any other suitable range of values ​​that enables the carrier ion supply layers 706 to function as described herein.

[0114] In one embodiment, the carrier ion supply layer 706 is sized to provide at least 15% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. For example, in one such embodiment, the carrier ion supply layer 706 is sized to include sufficient carrier ions (e.g., lithium, magnesium, or aluminum ions) to provide at least 30% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. By way of further example, in one such embodiment, the carrier ion supply layer 706 is sized to include sufficient carrier ions to provide at least 100% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. By way of further example, in one such embodiment, the carrier ion supply layer 706 is sized to include sufficient carrier ions to provide at least 200% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. By way of further example, in one such embodiment, the carrier ion supply layer 706 is sized to include sufficient carrier ions to provide at least 300% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. By way of further example, in one such embodiment, the carrier ion supply layer 706 is sized to include sufficient carrier ions to provide between about 100% and about 200% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100.

[0115] During the assembly process of the auxiliary electrode 502, the separator 702 may be cut from stock material or may be prefabricated to achieve the width 804 and length 808 as shown in FIG. 8. The conductive layer 704 may be cut from stock material or may be prefabricated to achieve the width 816 and length 822 shown in FIG. 8. In some embodiments, the conductive layer 704 is prefabricated to include a conductive tab 508-2 having a first end 812 mechanically and electrically affixed to the conductive layer 704 as depicted in FIG. 8. In other embodiments, the conductive tab 508-2 is cut from stock material and mechanically and electrically coupled to the conductive layer 704 (e.g., by spot welding or soldering the first end 812 to the conductive layer 704). In some embodiments, the carrier ion supply layer 706 is cut to size from a stock material and bonded or otherwise laminated to the conductive layer 704 (e.g., by cold welding the carrier ion supply layer 706 onto the conductive layer 704) to achieve the orientation depicted in Figure 8, with the second surface 827 of the carrier ion supply layer 706 in contact with the first surface 814 of the conductive layer 704. For example, the material (e.g., lithium) used to form the carrier ion supply layer 706 may be present in stock form as a roll of lithium sheets cut to size.

[0116] In another embodiment, the conductive layer 704 is prefabricated to include a carrier ion supply layer 706 arranged in the orientation depicted in Figure 8. In this embodiment, the conductive layer 704 is disposed within the first portion 805 of the separator 702 along the X-axis, and the second surface 815 of the conductive layer 704 contacts the first surface 802 of the separator 702.

[0117] 9 is a perspective view of the auxiliary electrode 502 at an intermediate stage in the auxiliary electrode fabrication process. At this stage, the conductive layer 704 is disposed on the first portion 805 of the separator 702, and the conductive tab 508-2 extends from a first end 812 attached to the conductive layer 704 to the left (Y-axis direction) of FIG. 9, away from the separator 702 and the conductive layer 704 toward a second end 813. The first surface 802 of the separator 702 is covered by the conductive layer 704 in the first portion 805 of the separator 702, while the first surface 802 of the separator remains uncovered in the second portion 806 of the separator 702.

[0118] To continue the fabrication process of the auxiliary electrode 502, in one embodiment, the second portion 806 of the separator 702 is folded in the direction of the left-facing arrow 902 in FIG. 9 (around an axis parallel to the X-axis) such that the first surface 802 in the second portion 806 of the separator 702 contacts the first surface 826 of the carrier ion supply layer 706 and the first surface 814 of the conductive layer 704 exposed between the carrier ion supply layers 706. If the separator 702 includes a first separator layer 702-1 and a second separator layer 702-2, the second separator layer may be positioned such that the first surface 802 of the second separator layer contacts the first surface 826 of the carrier ion supply layer 706 and the first surface 814 of the conductive layer 704 exposed between the carrier ion supply layers 706.

[0119] 10 is a perspective view of the auxiliary electrode 502 at another intermediate stage of the manufacturing process after folding the second portion 806 of the separator 702 as described above. At this stage, the separator 702 encapsulates the conductive layer 704 and the carrier ion supply layer 706, leaving a portion between the first end 812 of the conductive tab 508-2 and the second end 813 of the conductive tab 508-2 uncovered by the separator 702. The separator 702 can then be bonded to itself along at least a portion of the separator's periphery 1002 to encapsulate the conductive layer 704 within the separator's first portion 805 and the separator's second portion 806 along the separator's first surface 802 (not visible in FIG. 10).

[0120] In one embodiment, the separator 702 is bonded to itself along at least a portion of the separator's perimeter 1002 using a hot melt process, a welding process, a bonding process, or the like. In Fig. 10, the auxiliary electrode 502 at this stage includes a first side 1004 and a second side 1005 opposite the first side 1004. The first side 1004 includes the second surface 803 of the separator 702, which covers the carrier ion supply layer 706 in a first region 818-1 adjacent the first end 820 of the conductive layer 704 (not visible in Fig. 10) and in a second region 818-2 adjacent the second end 821 of the conductive layer 704 (not visible in this view). 10, the first region 818-1 is proximate to the first end 812 of the conductive tab 508-2 and the second region 818-2 is disposed away from the first end 812 of the conductive tab 508-2. The first end 812 of the conductive tab 508-2 is electrically coupled to the conductive layer 704 in a third region 818-3 of the conductive layer 704. In some embodiments, the conductive tab 508 can be extended (e.g., along with the conductive tab 508-1, as shown in FIG. 11, which shows the auxiliary electrode 502 after assembly).

[0121] Implementing a fabrication process for the cushioning system 500 (see FIGS. 6 and 7) in response to fabrication of the auxiliary electrode 502 continues as follows. FIGS. 12-16 are perspective views of the cushioning system 500 at various stages of the fabrication process. Referring to FIG. 12, the second region 818-2 of the auxiliary electrode 502 is inserted into the pouch 514 of the first enclosure layer 510, the second side 1005 of the auxiliary electrode is disposed in the pouch 514 toward the first enclosure layer 510, and the first side 1004 of the auxiliary electrode is disposed in the pouch 514 away from the first enclosure layer 510. The third region 818-3 and the first region 818-1 of the auxiliary electrode 502 extend away from the pouch 514 along the Y-axis direction.

[0122] With the auxiliary electrode 502 oriented in the pouch 514 as depicted in FIG. 12, the secondary battery 100 is placed on the auxiliary electrode 502 in the pouch 514 corresponding to the second region 818-2 of the auxiliary electrode 502 (see FIG. 13). In this embodiment, the first major surface 126 (see FIG. 1, not visible in FIG. 13) of the secondary battery 100 contacts the auxiliary electrode 502 in the pouch 514, and the second major surface 127 of the secondary battery is disposed away from the auxiliary electrode 502. The electrical terminals 124, 125 of the secondary battery 100 extend away from the pouch 514 in the Y-axis direction of FIG. 13, positioning the electrical terminals outside the perimeter 512 of the first enclosure layer 510. At this stage in the fabrication process of the buffer system 500, in one embodiment, an electrolyte is added to the pouch 514. In another embodiment, the separator 702 of the auxiliary electrode 502 is pre-impregnated with the electrolyte.

[0123] With the secondary battery 100 loaded onto the second region 818-2 of the auxiliary electrode 502 in the pouch 514, the auxiliary electrode 502 is folded in the direction of the arrow 1302 to position the first side 1004 of the first region 818-1 of the auxiliary electrode 502 in contact with the second main surface 127 of the secondary battery 100, as depicted in FIG. 14. In this configuration, both main surfaces 126, 127 of the secondary battery 100 (see FIG. 1) are electrochemically bonded to the carrier ion supply layer 706 of the auxiliary electrode 502 using the separator 702 (see FIGS. 7-11) and an electrolyte disposed between each of the main surfaces 126, 127 of the secondary battery 100 and the carrier ion supply layer 706.

[0124] FIG. 15 is a cross-sectional view of the cushioning system 500 taken along the line AA in FIG. 14. In this view, the layers of the cushioning system 500 in the pouch 514 of the first enclosure layer 510 are visible. In particular, FIG. 15 illustrates the arrangement of the secondary battery 100 and the auxiliary electrode 502 in the pouch 514, specifically, from top to bottom, the separator 702, the conductive layer 704, one of the carrier ion supply layers 706, the separator 702, and the second main surface 127 of the secondary battery 100 in the casing 116. FIG. 15 further illustrates the first enclosure layer 510, the separator 702, the conductive layer 704, one of the carrier ion supply layers 706, the separator 702, and the first main surface 126 of the secondary battery 100 in the casing 116, which are stacked in this order from bottom to top.

[0125] With the secondary battery 100 sandwiched by the auxiliary electrode 502 within the pouch 514, as illustrated in FIG. 15, the second enclosure layer 511 is aligned to the first enclosure layer 510, as depicted in FIG. 16. After the second enclosure layer 511 is properly positioned relative to the first enclosure layer 510, the enclosure layers 510, 511 are sealed along a sealing line 1602 (shown in dashed lines in FIG. 16) to form the enclosure 504. The enclosure layers 510, 511 may be sealed along the sealing line 1602 by welding, heat sealing, adhesives, combinations thereof, and the like. In another embodiment, the enclosure layers 510, 511 can be sealed along three sides of the sealing line 1602 to form a pocket therein. In this embodiment, the secondary battery 100 can be placed within the pocket, after which the final edge of the sealing line 1602 is sealed. In one embodiment, the sealing line 1602 is sealed using a hot press, which applies a controlled temperature and pressure to the sealing line 1602 to bond or fuse the enclosure layers 510, 511 together along the sealing line 1602. In another embodiment, a vacuum is applied to the secondary battery 100 during the sealing process to evacuate any excess volume occupied by air or other gases. The time that the sealing line 1602 undergoes the hot press may be controlled and depends on the material selected for the enclosure layers 510, 511. When sealed over the secondary battery 100, the sealed enclosure layers 510, 511 form the buffer system 500. When sealed, the buffer system 500 is liquid-tight and / or air-tight, depending on the desired application. The electrical terminals 124 and 125 of the secondary battery 100 and the conductive tab 508-1 remain exposed and are not covered by the enclosure layers 510, 511, allowing a subsequent buffering process to be applied to the secondary battery 100.

[0126] With the secondary battery 100 and the carrier ion supply layer 706 of the auxiliary electrode 502 (not visible in FIG. 16 ) electrochemically bonded together within the enclosure 504 of the buffering system 500, a carrier ion buffering process is performed on the secondary battery 100 during or after the initial formation of the secondary battery 100. Generally, this carrier ion buffering process transfers carrier ions from the carrier ion supply layer 706 of the auxiliary electrode 502 to each of the first major surface 126 of the secondary battery 100 and the second major surface 127 of the secondary battery 100 (see FIG. 15 ). Generally, transferring carrier ions from both major surfaces 126, 127 of the secondary battery 100 to the secondary battery 100 as depicted in FIG. 15 provides the technical advantage that more carrier ions are loaded into the anode and / or cathode of the secondary battery 100, thereby distributing forces generated by the expansion of the anode and / or cathode more evenly across the casing 116 of the secondary battery 100.

[0127] Either before or after inserting the secondary battery 100 into the buffer system 500, the secondary battery 100 is charged (e.g., via electrical terminals 124, 125) by transferring carrier ions from the secondary battery's cathode structure 206 to the secondary battery's anode structure 207. Charging may be interrupted when the secondary battery's positive electrode 208 reaches its end-of-charge design voltage. During the initial charging cycle, an SEI may form on the surface of the secondary battery's anode structure 207. To compensate for the loss of carrier ions to the SEI and to further provide additional carrier ions to mitigate long-term secondary reactions during cycling in which carrier ions are lost due to side reactions, the positive electrode 208 and / or negative electrode 209 of the secondary battery 100 can be replenished by applying a voltage across the auxiliary electrode 502 and the cathode structure 206 and / or anode structure 207 (e.g., via the conductive tab 508-1 of the auxiliary electrode 502 and one of the electrical terminals 124, 125) to drive carrier ions from the carrier ion supply layer 706 of the auxiliary electrode 502 to the cathode structure 206 and / or anode structure 207 of the secondary battery 100. Upon completion of the transfer of carrier ions from the auxiliary electrode 502 to the secondary battery 100, the negative electrode 209 of the secondary battery 100 is charged again, and this time carrier ions are transferred from the cathode structure 206 of the secondary battery 100 to the anode structure 207 of the secondary battery.

[0128] In one embodiment, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 during the buffering process is about 50% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In other embodiments, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 during the buffering process is about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In some embodiments, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 is within a range of values ​​from about 1% to about 100% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In one particular embodiment, the negative electrode 209 of the secondary battery 100 has about 170% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100 stored as carrier ions when the secondary battery 100 is charged, and has about 70% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100 stored as carrier ions when the secondary battery 100 is discharged. The excess carrier ions in the negative electrode 209 of the secondary battery 100 provided during the buffering process provides the technical advantage of mitigating the loss of carrier ions in the secondary battery 100 due to the SEI upon initial formation. Furthermore, the excess carrier ions in the negative electrode 209 of the secondary battery 100 provided during the buffering process provides the technical advantage of mitigating the loss of carrier ions in the secondary battery 100 due to side reactions that deplete carrier ions in the secondary battery 100 when the secondary battery 100 is cycled during use, which reduces the capacity loss of the secondary battery 100 over time.

[0129] In some embodiments, the transfer of carrier ions from the auxiliary electrode 502 to the secondary battery 100 may occur simultaneously with the initial formation of the secondary battery 100 (e.g., during a first charge of the secondary battery 100) and / or during a subsequent charge of the secondary battery 100 after the initial formation. In these embodiments, the carrier ions transfer from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100. Simultaneously or based on a time delay or pattern, the carrier ions transfer from the auxiliary electrode 502 to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100.

[0130] In yet another embodiment, the positive electrode 208 can be replenished with carrier ions by simultaneously transferring carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 and transferring carrier ions from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100. Referring to FIG. 6, a voltage is applied across the electrical terminals 124, 125 of the secondary battery 100 to drive the carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. While the carrier ions are transferring from the positive electrode 208 to the negative electrode 209, a voltage is applied across the conductive tab 508-1 of the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100 to drive the carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100. Thus, carrier ions are transferred from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 at the same time that carrier ions are transferred from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. That is, a voltage sufficient to drive carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100 is maintained across the positive electrode 208 and the negative electrode 209 of the secondary battery 100, and at the same time, a voltage sufficient to drive carrier ions from the auxiliary electrode 502 to the positive electrode 208 is maintained across the conductive tab 508-1 of the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100. In another embodiment, the initiation of transfer of carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 may begin at the same time as the initiation of transfer of carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. In one embodiment, the rate of carrier ion migration from the positive electrode 208 to the negative electrode 209 of the secondary battery 100 is equal to or greater than the rate of carrier ion migration from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100, so that a good overall rate of carrier ion migration from the auxiliary electrode 502 to the negative electrode 209 of the secondary battery 100 via the positive electrode 208 can be maintained. That is, the relative rates of migration between the positive electrode 208 and the negative electrode 209, and between the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100 can be maintained such that they do not exceed the overall capacity of the positive electrode 208 for additional carrier ions.This allows the positive electrode 208 to be maintained in a state capable of accepting new carrier ions from the auxiliary electrode 502, and allows the carrier ions to subsequently move to the negative electrode 209 of the secondary battery 100.

[0131] In one embodiment, without being limited by any particular theory, carrier ions are transferred from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 as part of replenishing the negative electrode 209 of the secondary battery 100 (as opposed to transferring directly from the auxiliary electrode 502 to the negative electrode 209 of the secondary battery) because the positive electrode 208 may be able to receive carrier ions more uniformly across its surface, thus allowing the carrier ions to participate more uniformly in their transfer between the positive electrode 208 and the negative electrode 209 of the secondary battery 100.

[0132] After the buffering process is performed on the secondary battery 100 using the buffering system 500, the auxiliary electrode 502 can be removed from the buffering system 500 to improve the energy density of the secondary battery 100 in its final form. For example, after the buffering process, the carrier ion supply layer 706 (see FIG. 7) may be removed from the conductive layer 704 that has been electrochemically transferred to the secondary battery 100. Thus, the auxiliary electrode 502 may not be needed at this point. To remove the auxiliary electrode 502 from the enclosure 504 after the buffering process is performed, the enclosure layers 510, 511 of the enclosure may be cut along the cut lines 1702 illustrated as solid lines in FIG. 17, allowing the enclosure layers 510, 511 to be peeled away adjacent to the auxiliary electrode 502. The auxiliary electrode 502 is removed from the enclosure 504 of the buffering system 500, and the secondary battery 100 is left in the pouch 514 (see FIG. 12). The enclosure layers 510, 511 can then be resealed along a final sealing line 1704, illustrated as a dashed line, to form the enclosure 504 prior to use of the secondary battery 100. This resealing may be performed using any of the processes previously described for sealing the first enclosure layer 510 and the second enclosure layer 511 together.

[0133] FIG 18 is a flowchart of a method 1800 of pre-lithiating a secondary battery with carrier ions using an auxiliary electrode of an exemplary embodiment, and FIGS. 19-21 are flowcharts depicting further details of method 1800. Although method 1800 is described with respect to secondary battery 100, buffer system 500, and auxiliary electrode 502 of FIGS. 1-17, method 1800 may be applied to other systems not shown. The steps of method 1800 are not all inclusive, and method 1800 may include other steps not shown. Additionally, the steps of method 1800 may be performed in an alternate order.

[0134] In this embodiment, the secondary battery 100 (see FIG. 1 ) has opposing major surfaces 126, 127 and electrical terminals 124, 125. The electrical terminals 124, 125 are coupled to one of the positive electrode 208 of the secondary battery 100 (e.g., a group of cathode structures 206 in the secondary battery 100 as depicted in FIG. 2 ) and the negative electrode 209 of the secondary battery 100 (e.g., a group of anode structures 207 in the secondary battery 100 as depicted in FIG. 2 ). Between the negative electrode 209 and the positive electrode 208, the secondary battery 100 includes an electrolyte-permeated microporous separator layer 108 (see FIG. 2 ) that is in ionic contact with the negative electrode 209 and the positive electrode 208. The negative electrode 209 includes a layer 104 of a positive electrode active material, such as silicon or an alloy thereof, that has a coulombic capacity for carrier ions. The positive electrode 208 includes a cathode active material layer 106 that has a coulombic capacity of carrier ions, and the coulombic capacity of the negative electrode 209 exceeds the coulombic capacity of the positive electrode 208 .

[0135] The auxiliary electrode 502 (see FIG. 6) is placed in contact with the major surfaces 126, 127 of the secondary battery 100 to form an auxiliary subassembly 516, in which the auxiliary electrode 502 includes a conductive layer 704, a carrier ion supply layer 706 disposed on the conductive layer 704 adjacent the major surfaces 126, 127 of the secondary battery 100, a separator 702 disposed between the carrier ion supply layer 706 and the major surfaces 126, 127 of the secondary battery, and a conductive tab 508 coupled to the conductive layer 704 (see step 1802 of FIG. 18 and FIGS. 12-15).

[0136] The auxiliary subassembly 516 is installed within the enclosure 504, where the electrical terminals 124, 125 of the secondary battery 100 and the conductive tab 508 of the auxiliary electrode 502 electrically extend from the outer periphery 506 of the enclosure 504 (step 1804, and see FIG. 16).

[0137] Carrier ions are transferred from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100 by applying an electric potential voltage across the electrical terminals 124, 125 to at least partially charge the secondary battery 100 (see step 1806). The charging may be interrupted when the positive electrode 208 of the secondary battery 100 reaches its end-of-charge design voltage. During the initial charging cycle, an SEI may form on the internal structural surface of the negative electrode 209 of the secondary battery 100.

[0138] To compensate for the loss of carrier ions to the SEI and to further provide additional carrier ions to mitigate long-term secondary reactions during cycling in which carrier ions are lost to side reactions, carrier ions are transferred from the carrier ion supply layer 706 of the auxiliary electrode 502 to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100 by applying a potential voltage across the conductive tab 508 of the auxiliary electrode 502 and one or more of the electrical terminals 124, 125 of the secondary battery 100 (see step 1808 of FIG. 16). Generally, this carrier ion buffering process transfers carrier ions from the carrier ion supply layer 706 of the auxiliary electrode 502 to each of the first major surface 126 of the secondary battery 100 and the second major surface 127 of the secondary battery 100 (see FIG. 15). Generally, transferring carrier ions into the secondary battery 100 from both of the major surfaces 126, 127 of the secondary battery 100, as depicted in FIG. 15, provides the technical advantage that more carrier ions are loaded into the cathode and / or anode of the secondary battery 100, thereby distributing forces generated by expansion of the cathode and / or anode more evenly across the casing 116 of the secondary battery 100.

[0139] In one embodiment, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 is about 50% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In other embodiments, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 is about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In some embodiments, the amount of carrier ions transferred from the auxiliary electrode 502 to the secondary battery 100 is within a range of values ​​from about 1% to about 100% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100. In one particular embodiment, the negative electrode 209 of the secondary battery 100 has about 170% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100 stored as carrier ions when the secondary battery 100 is charged, and has about 70% of the reversible coulombic capacity of the positive electrode 208 of the secondary battery 100 stored as carrier ions when the secondary battery 100 is discharged. The excess carrier ions in the negative electrode 209 of the secondary battery 100 provided during the buffering process provides the technical advantage of mitigating the loss of carrier ions in the secondary battery 100 due to the SEI upon initial formation. Furthermore, the excess carrier ions in the negative electrode 209 of the secondary battery 100 provided during the buffering process provides the technical advantage of mitigating the loss of carrier ions in the secondary battery 100 due to side reactions that deplete carrier ions in the secondary battery 100 when the secondary battery 100 is cycled during use, which reduces the capacity loss of the secondary battery 100 over time.

[0140] In some embodiments, the transfer of carrier ions from the auxiliary electrode 502 to the secondary battery 100 may occur simultaneously with the initial formation of the secondary battery 100 (e.g., during a first charge of the secondary battery 100) and / or during a subsequent charge of the secondary battery 100 after the initial formation. In these embodiments, the carrier ions transfer from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100. Simultaneously or based on a time delay or pattern, the carrier ions transfer from the auxiliary electrode 502 to the positive electrode 208 and / or negative electrode 209 of the secondary battery 100.

[0141] The carrier ions are again transferred from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100 by applying a potential voltage across the electrical terminals 124, 125 of the secondary battery 100, charging the secondary battery 100 until the negative electrode 209 exceeds 100% of the coulombic capacity of the positive electrode 208 stored as carrier ions (see step 1810).

[0142] In yet another embodiment, the positive electrode 208 can be replenished with carrier ions by simultaneously transferring carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 and transferring carrier ions from the positive electrode 208 of the secondary battery 100 to the negative electrode 209 of the secondary battery 100. Referring to FIG. 6, a voltage is applied across the electrical terminals 124, 125 of the secondary battery 100 to drive the carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. While the carrier ions are transferring from the positive electrode 208 to the negative electrode 209, a voltage is applied across the conductive tab 508-1 of the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100 to drive the carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100. Thus, carrier ions are transferred from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 at the same time that carrier ions are transferred from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. That is, a voltage sufficient to drive carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100 is maintained across the positive electrode 208 and the negative electrode 209 of the secondary battery 100, and at the same time, a voltage sufficient to drive carrier ions from the auxiliary electrode 502 to the positive electrode 208 is maintained across the conductive tab 508-1 of the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100. In another embodiment, the initiation of transfer of carrier ions from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 may begin at the same time as the initiation of transfer of carrier ions from the positive electrode 208 to the negative electrode 209 of the secondary battery 100. In one embodiment, the rate of carrier ion migration from the positive electrode 208 to the negative electrode 209 of the secondary battery 100 is equal to or greater than the rate of carrier ion migration from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100, so that a good overall rate of carrier ion migration from the auxiliary electrode 502 to the negative electrode 209 of the secondary battery 100 via the positive electrode 208 can be maintained. That is, the relative rates of migration between the positive electrode 208 and the negative electrode 209, and between the auxiliary electrode 502 and the positive electrode 208 of the secondary battery 100 can be maintained such that they do not exceed the overall capacity of the positive electrode 208 for additional carrier ions.This allows the positive electrode 208 to be maintained in a state capable of accepting new carrier ions from the auxiliary electrode 502, and allows the carrier ions to subsequently move to the negative electrode 209 of the secondary battery 100.

[0143] In one embodiment, without being limited by any particular theory, carrier ions are transferred from the auxiliary electrode 502 to the positive electrode 208 of the secondary battery 100 as part of replenishing the negative electrode 209 of the secondary battery 100 (as opposed to transferring directly from the auxiliary electrode 502 to the negative electrode 209 of the secondary battery 100) because the positive electrode 208 may be able to receive carrier ions more uniformly across its surface, thus allowing the carrier ions to participate more uniformly in their transfer between the positive electrode 208 and the negative electrode 209 of the secondary battery 100.

[0144] In some embodiments of method 1800, enclosure 504 is opened (see step 1902 of FIG. 19 ) and auxiliary electrode 502 is removed (see step 1904) from enclosure 504. In response to removing auxiliary electrode 502 from enclosure 504, the enclosure is resealed (see step 1906) to enclose secondary battery 100.

[0145] As previously described with respect to step 1804 detailed above, one particular embodiment installs the auxiliary subassembly 516 within the enclosure 504, but includes installing the auxiliary subassembly 516 on the first enclosure layer 510 (see step 2002 of FIG. 20). A second enclosure layer 511 is installed on the first enclosure layer 510 (see step 2004), and the first enclosure layer 510 and the second enclosure layer 511 are sealed together along the sealing line 1602 to form the enclosure 504 (see step 2006).

[0146] The enclosure layers 510, 511 may be sealed along a sealing line 1602 (see FIG. 16 ) by welding, heat sealing, adhesives, combinations thereof, and the like. In another embodiment, the enclosure layers 510, 511 may be sealed along three sides of the sealing line 1602 to form a pocket therein. In this embodiment, the secondary battery 100 may be placed in the pocket, after which the final edge of the sealing line 1602 is sealed. In one embodiment, the sealing line 1602 is sealed using a hot press, which applies a controlled temperature and pressure to the sealing line 1602 to bond or fuse the enclosure layers 510, 511 together along the sealing line 1602. In another embodiment, a vacuum is applied to the secondary battery 100 during the sealing process to evacuate any excess volume occupied by air or other gases. The time that the sealing line 1602 undergoes the hot press may be controlled and depends on the material selected for the enclosure layers 510, 511. When sealed over the secondary battery 100, the sealed enclosure layers 510, 511 form the cushioning system 500. When sealed, the cushioning system 500 is liquid-tight and / or air-tight, depending on the desired application. The electrical terminals 124, 125 and the conductive tabs 508 of the secondary battery 100 remain exposed and are not covered by the enclosure layers 510, 511.

[0147] In embodiments in which the first enclosure layer 510 includes a pouch 514, placing the auxiliary subassembly 516 within the enclosure 504 includes first disposing the auxiliary subassembly 516 within the pouch 514 (see step 2102 of FIG. 21 ). In some embodiments, electrolyte is added to the pouch 514 (e.g., either before or after placing the auxiliary subassembly 516 within the pouch 514), and then the enclosure 504 is formed by sealing the first enclosure layer 510 and the second enclosure layer 511 together along the seal line 1602.

[0148] 22 is a flow chart of an exemplary method 2200 of forming a secondary battery assembly, for example, following a pre-lithiation or buffering process to prepare the secondary battery assembly for an end use. Although method 2200 is described with respect to secondary battery 100, buffering system 500, and auxiliary electrode 502 of FIGS. 1-17, method 2200 may be applied to other systems not shown. The steps of method 2200 are not all inclusive, and method 2200 may include other steps not shown. Additionally, steps of method 2200 may be performed in an alternate order.

[0149] In the exemplary method 2200, the secondary battery 100 is placed 2202 in a pouch 514 defined by an enclosure 504, and the auxiliary electrode 502 is placed 2204 in the pouch 514, such that the auxiliary electrode 502 is in contact with the secondary battery 100. A buffering process, such as a buffering or pre-lithiation process described herein, is performed 2206 on the lithium-containing secondary battery to transfer carrier ions from the auxiliary electrode 502 to the lithium-containing secondary battery 100.

[0150] After the buffering process is performed 2206, the auxiliary electrode 502 is removed 2208 from the pouch 514. As described above, for example, the enclosure layers 510, 511 of the enclosure 504 can be cut or separated 1702 along a separation line ( FIG. 17 ) after the buffering or pre-lithiation process, and the enclosure layers 510, 511 can be peeled away adjacent the auxiliary electrode 502 to remove 2208 the auxiliary electrode 502 from the pouch 514 of the enclosure 504. The secondary battery 100 can be left in the pouch 514 after the auxiliary electrode 502 is removed 2208, or can be repositioned in the pouch 514.

[0151] After the auxiliary electrode 502 is removed from the pouch 514, the enclosure 504 can then be sealed (or resealed) 2210 with the secondary battery 100 disposed within the pouch 514. For example, the enclosure layers 510, 511 can be sealed 2210 along a final seal line 1704 using any of the processes previously described for sealing the first enclosure layer 510 and the second enclosure layer 511 together. The sealed enclosure 504 may then be trimmed or cut 2212 along one or more final cut lines 1706, shown in solid lines in FIG. 17, such that multiple flaps are formed from the enclosure 504, with each flap extending outwardly from the pouch 514 at a respective fold line. The enclosure 504 may be trimmed 2212 along one or more final cut lines 1706 ( FIG. 17 ) by die cutting, rotary cutting, reciprocating cutting, laser cutting, fluid jet cutting, and combinations thereof. As described further herein, each of the flaps remaining after the final trim 2212 may be folded 2214 around the respective fold line toward and in contact with the pouch 514 to attach each of the flaps to the pouch 514. In some embodiments, for example, each of the multiple flaps may be folded to contact and be connected or secured to the pouch 514 to reduce the footprint of the secondary battery assembly for end use and provide a compact package. In some embodiments, an adhesive may be applied to each of the flaps and / or a portion of the pouch 514, and each flap may be folded around the respective fold line to contact the pouch 514 to adhere each of the flaps to the pouch 514.

[0152] 23 and 24 are front and rear perspective views, respectively, of an exemplary secondary battery assembly 2300 at an intermediate stage of formation (e.g., after the sealing 2210 and trimming 2212 steps, but before the flap folding step 2214 of the method 2200 of FIG. 22). FIG. 25 is another front perspective view of the secondary battery assembly 2300. The secondary battery assembly 2300 includes a secondary battery 100 and an enclosure 504, with the secondary battery 100 shown disposed within a pouch 514 of the enclosure 504 in FIGS. 23-25.

[0153] In this embodiment, the pouch 514 is formed as a right angle prism and includes a planar rectangular base 2302, a planar rectangular cover 2304 (FIG. 24) disposed opposite and spaced apart from the base 2302 (Z direction as shown in FIGS. 23 and 24), a first sidewall 2306 extending from the base 2302 to the cover 2304, and a second sidewall 2306 disposed opposite and spaced apart from the first sidewall (X direction as shown in FIGS. 23 and 24) extending from the base 2302 to the cover 2304. 23 and 24 ), and a second end wall 2312 disposed opposite the first end wall 2310 and spaced apart from the first end wall 2310 (in the Y direction as shown in FIGS. 23 and 24 ) and extending from the first side wall 2306 to the second side wall 2308 and from the base 2302 to the cover 2304. In the illustrated embodiment, the electrical terminals 124, 125 of the secondary battery 100 extend outwardly therefrom through the second end wall 2312. In this embodiment, the base 2302 and each of the first side wall 2306, second side wall 2308, first end wall 2310, and second end wall 2312 are defined by the first enclosure layer 510, and the cover 2304 is defined by the second enclosure layer 511. It should be understood that in other embodiments, the elements of the pouch 514 may be formed from either the first enclosure layer 510 or the second enclosure layer 511. Furthermore, although in the illustrated embodiment, the pouch 514 and each of the base 2302, cover 2304, side walls 2306, 2308, and end walls 2310, 2312 are rectangular, in other embodiments the pouch 514 and its elements may be shaped other than rectangular.

[0154] As shown in FIGS. 23-25, the enclosure 504 includes a plurality of flaps 2314 extending outwardly from the pouch 514 at respective fold lines 2316 following the sealing 2210 and trimming 2212 steps of the method 2200 (FIG. 22). As described further herein, the fold lines 2316 may include lines along which one of the flaps 2314 exits or joins the pouch 514, and may include lines that are not perforated or foldable, such as lines around which the flap 2314 is folded, e.g., to attach the flap 2314 to the pouch 514. As used herein, the fold lines 2316 need not be scored, perforated, scored, or otherwise outlined to be considered fold lines. Each flap 2314 includes a first surface 2318 (FIG. 23) and an opposing second surface 2320 (FIG. 24). The first surface 2318 faces generally toward the pouch 514 and away from the cover 2304, and the second surface 2320 faces generally away from the pouch 514 (in the Z direction, as shown in FIG. 24 ). In the illustrated embodiment, the first surface 2318 of each of the flaps 2314 is defined by the first enclosure layer 510, and the second surface 2320 of each flap 2314 is defined by the second enclosure layer 511.

[0155] The plurality of flaps 2314 are formed during the sealing 2210 and / or trimming 2212 steps described above. More specifically, the size and shape of each of the flaps 2314 may be set when the enclosure 504 is sealed and trimmed after removal of the auxiliary electrode 502. In the illustrated embodiment, each of the flaps 2314 is rectangular in shape, although other embodiments may have flaps that are other than rectangular in shape. In some embodiments, the step 2212 of trimming the enclosure 504 may include trimming the enclosure 504 so that each of the flaps 2314 has a width 2322 ( FIG. 25 ) measured from the respective fold line 2316 to the free end 2326 of the flap 2314 (i.e., in the Z or Y direction as shown in FIG. 25 ), which is less than or equal to the height 2324 of the secondary battery 100 and / or pouch 514 measured from the base 2302 to the cover 2304 (i.e., in the Z direction as shown in FIG. 25 ), such that when the flap 2314 is folded into contact with the pouch 514, the flap 2314 does not extend vertically (in the Z direction as shown in FIG. 25 ) beyond the pouch 514.

[0156] Although other embodiments may include additional or alternative flaps, in the illustrated embodiment, the secondary battery assembly 2300 includes a first side flap 2328, a second side flap 2330, and an end flap 2332. The first side flap 2328 extends outwardly (in the X direction as shown in FIGS. 23-25 ​​) from a first side wall 2306 of the pouch at a first fold line 2334, the second side flap 2330 extends outwardly (in the X direction as shown in FIGS. 23-25 ​​) from a second side wall 2308 of the pouch at a second fold line 2336, and the end flap 2332 extends outwardly (in the Y direction as shown in FIGS. 23-25 ​​) from a first end wall 2310 of the pouch at a third fold line 2338.

[0157] 26-31 illustrate steps of an exemplary method of forming a secondary battery assembly 2300. These steps may be performed immediately after the sealing step 2210 and trimming step 2212 described with reference to FIG 22, or after one or more intermediate steps have been performed on the secondary battery assembly 2300. Additionally, the steps illustrated in FIGS. 26-31 may be performed sequentially in the order shown, or one or more steps may be performed in a different order.

[0158] 26, the adhesive 2602 is applied to at least one of the first surface 2318 of the first side flap 2328 and the first side wall 2306 of the pouch, and the first surface 2318 of the second side flap 2330 and at least one of the second side wall 2308 of the pouch. In the illustrated embodiment, in addition to or instead of applying the adhesive 2602 to the pouch 514, the adhesive 2602 may be applied to the first side flap 2328 and / or the second side flap 2330 of the pouch, while the bonding agent 2602 is applied to the first side wall 2306 of the pouch and the second side wall 2308 of the pouch. In some embodiments, for example, the adhesive 2602 is applied to each of the first surface 2318 of the first side flap 2328 and the first surface 2318 of the second side flap 2330 instead of being applied to the first and second side walls 2306, 2308 of the pouch 514. Examples of suitable adhesives include, but are not limited to, for example, adhesive strips (e.g., tape), liquid adhesives, epoxies, resins, and combinations thereof. In one exemplary embodiment, the adhesive 2602 comprises an adhesive strip.

[0159] As shown in FIGS. 26-27 , after the adhesive 2602 is applied, the first side flap 2328 is folded about the first fold line 2334 toward and in contact with the first side wall 2306 of the pouch to connect the first side flap 2328 to the first side wall 2306 of the pouch, and the second side flap 2330 is folded about the second fold line 2336 toward and in contact with the second side wall 2308 of the pouch to connect the second side flap 2330 to the second side wall 2308 of the pouch. In some embodiments, the first side flap 2328 and / or the second side flap 2330 may initially be folded only partially toward the pouch 514 (e.g., so as not to contact the pouch 514) or may be folded so as to contact and / or be attached to the pouch 514 during one or more subsequent steps (e.g., a pressing step as further described herein).

[0160] As shown in FIG. 27, after the first and second side flaps 2328, 2330 are folded toward and optionally contact the pouch 514, a portion of the first side flap 2328 extends beyond the first end wall 2310 of the pouch (in the Y direction shown in FIG. 27) to define a first tab 2702, and a portion of the second side flap 2330 extends beyond the first end wall 2310 of the pouch (in the Y direction shown in FIG. 27) to define a second tab 2704.

[0161] 28, adhesive 2802 is also applied to at least one of the first surface 2318 of the end flap 2332 and the first end wall 2310 of the pouch 514. In the illustrated embodiment, adhesive 2802 is applied to the first end wall 2310 of the pouch, although in addition to or instead of applying adhesive 2802 to the pouch 514, adhesive 2802 may be applied to the end flap 2332. In some embodiments, for example, adhesive 2802 is applied to the first surface 2318 of the end flap 2332 instead of being applied to the first end wall 2310 of the pouch 514. The adhesive 2802 applied to the end flap 2332 and / or first end wall 2310 of the pouch 514 may include any of the adhesives described above with reference to adhesive 2602 (FIG. 26). The adhesive 2802 applied to the end flap 2332 and / or first end wall 2310 of the pouch 514 may be the same as or different from the adhesive 2602 applied to the first and second side walls 2306, 2308 and / or first and second side flaps 2328, 2330 of the pouch 514. In one exemplary embodiment, the adhesive 2802 comprises an adhesive strip.

[0162] 28 and 29 , after adhesive 2802 is applied to end flap 2332 and / or pouch first end wall 2310, end flap 2332 is folded toward and in contact with pouch first end wall 2310 about third fold line 2338 to connect end flap 2332 to pouch first end wall 2310. In some embodiments, end flap 2332 may be initially folded only partially toward pouch 514 (e.g., out of contact with pouch 514) or may be folded to contact and / or be attached to pouch 514 during one or more subsequent steps (e.g., a pressing step as further described herein).

[0163] When the end flap 2332 is folded toward, and optionally into contact with, the first end wall 2310 of the pouch 514, a portion of the first and second tabs 2702, 2704 may be folded along with the end flap 2332 due to the connections between the end flap 2332 and the first and second tabs 2702, 2704. As a result, an edge of each of the tabs 2702, 2704 may be oriented at an oblique angle relative to the other edges of the tabs 2702, 2704, as shown, for example, in FIG. 31 . For this reason, these tabs 2702, 2704 are sometimes colloquially referred to as "bat ears."

[0164] 30, the adhesive 3002 is also applied to at least one of the second surface 2320 of the end flap 2332 and the first surface 2318 of each of the first and second tabs 2702, 2704. In this embodiment, the adhesive 3002 is applied after the first side flap 2328, the second side flap 2330, and the end flap 2332 are folded toward and optionally in contact with the pouch 514, although in other embodiments the adhesive 3002 may be partially applied to one or more of the first side flap 2328, the second side flap 2330, and the end flap 2332 are folded toward and optionally in contact with the pouch 514. In the illustrated embodiment, the adhesive 3002 is applied to the second surface 2320 of the end flap 2332, although in addition to or instead of being applied to the end flap 2332, the adhesive 3002 may be applied to the first tab 2702 and / or the second tab 2704 (e.g., the first surface 2318 of the first tab 2702 and / or the second tab 2704). In some embodiments, for example, the adhesive 3002 is applied to the first surface 2318 of the first tab 2702 and the first surface 2318 of the second tab 2704 instead of being applied to the second surface 2320 of the end flap 2332. The adhesive 3002 applied to the end flap 2332 and / or the first tab 2702 and the second tab 2704 may include any of the adhesives described above with reference to adhesive 2602 ( FIG. 26 ) and adhesive 2802 ( FIG. 28 ). The adhesive 3002 applied to the end flap 2332 and / or the first and second tabs 2702, 2704 may be the same or different than the adhesive 2602, 2802 applied to the other flaps 2314 and / or the pouch 514. In one exemplary embodiment, the adhesive 3002 comprises an adhesive strip.

[0165] 31 , after the adhesive 3002 is applied, the first tab 2702 is folded toward and contacting the second surface 2320 of the end flap 2332 about the fourth fold line 3102 to connect the first tab 2702 to the end flap 2332, and the second tab 2704 is folded toward and contacting the second surface 2320 of the end flap 2332 about the fifth fold line 3104 to connect the second tab 2704 to the end flap 2332. In some embodiments, the first tab 2702 and / or the second tab 2704 may be initially folded only partially toward the end flap 2332 (e.g., not in contact with the end flap 2332) or may be folded to contact and / or be attached to the end flap 2332 during one or more subsequent steps (e.g., a pressing step as further described herein).

[0166] In some embodiments, the secondary battery assembly 2300 may undergo one or more attachment and / or heat treatment steps to facilitate maintaining adhesion between the flaps 2314 and the pouch 514. For example, the secondary battery assembly 2300 may be pressed and / or heated (simultaneously or in successive steps) after one or more flaps 2314 are folded towards and optionally in contact with the pouch 514 to promote adhesion between the one or more flaps 2314 and the pouch 514 and / or to reduce or mitigate internal stresses or strains in the flaps 2314 (particularly within the material of the enclosure 504) resulting from deformation of the flaps 2314 upon folding.

[0167] In some embodiments, for example, after the first side flap 2328 is folded towards and optionally in contact with the first side wall 2306 of the pouch and the second side flap 2330 is folded towards and optionally in contact with the second side wall 2308 of the pouch, the first side flap 2328 is pressed against the first side wall 2306 of the pouch and the second side flap 2330 is pressed against the second side wall 2308 of the pouch. The pressing force or pressure used to press the first side flap 2328 against the first side wall 2306 of the pouch and the second side flap 2330 against the second side wall 2308 of the pouch may be any suitable force or pressure that facilitates maintaining an adhesion or connection between the first and second side flaps 2328, 2330 and the pouch 514. In some embodiments, the first and second side flaps 2328, 2330 are pressed against the first side wall 2306 of the pouch and the second side wall 2308 of the pouch, respectively, by applying a pressing force across the first side wall 2306 of the pouch and the second side wall 2308 of the pouch equal to a pressure of at least 5 pounds per square inch (psi), at least 8 psi, at least 10 psi, at least 15 psi, at least 20 psi, at least 25 psi, at least 30 psi, at least 35 psi, between 5 psi and 50 psi, between 5 psi and 20 psi, between 10 psi and 40 psi, between 5 psi and 15 psi, or between 20 psi and 40 psi.

[0168] The first side flap 2328 and the second side flap 2330 may be pressed against the pouch 514 simultaneously or sequentially. Additionally, the secondary battery assembly 2300 may be heated before, during, or after the first side flap 2328 and the second side flap 2330 are pressed against the pouch 514. In one exemplary embodiment, the first side flap 2328 is pressed against the first side wall 2306 of the pouch and the second side flap 2330 is pressed against the second side wall 2308 of the pouch while the secondary battery assembly 2300 is heated at a first pressing temperature for a first pressing time. The first pressing temperature may be, for example, but is not limited to, in the range of 50° C. to 150° C., 70° C. to 150° C., 90° C. to 150° C., 90° C. to 140° C., 100° C. to 150° C., 90° C. to 130° C., 100° C. to 140° C., 110° C. to 150° C., 90° C. to 120° C., 100° C. to 130° C., 110° C. to 140° C., or 120° C. to 150° C. The first pressing time may be, for example, but is not limited to, in the range of 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0169] Additionally or alternatively, the end flap 2332, the first tab 2702, and the second tab 2704 may be pressed against the first end wall 2310 of the pouch after the end flap 2332 is folded toward and optionally in contact with the first end wall 2310 of the pouch and the first and second tabs 2702, 2704 are folded toward and optionally in contact with the end flap 2332. The pressing force or pressure used to press the end flap 2332, the first tab 2702, and the second tab 2704 against the first end wall 2310 of the pouch may be any suitable force or pressure that facilitates maintaining an adhesion or connection between the end flap 2332 and the first end wall 2310 of the pouch and / or between the first and second tabs 2702, 2704 and the end flap 2332. In some embodiments, the end flap 2332 and the first and second tabs 2702, 2704 are pressed against the first end wall 2310 of the pouch by applying a pressing force across the first end wall 2310 of the pouch equal to a pressure of at least 2.5 psi, at least 3 psi, at least 4 psi, at least 5 psi, at least 10 psi, at least 15 psi, at least 20 psi, 2.5 psi to 40 psi, 2.5 psi to 30 psi, 2.5 psi to 25 psi, 3 psi to 30 psi, 3 psi to 25 psi, 4 psi to 40 psi, 4 psi to 25 psi, 5 psi to 40 psi, 5 psi to 30 psi, 5 psi to 25 psi, 10 psi to 50 psi, 10 psi to 40 psi, 10 psi to 30 psi, 10 psi to 25 psi, 15 psi to 30 psi, or 20 psi to 35 psi.

[0170] The end flap 2332, the first tab 2702, and the second tab 2704 may be pressed simultaneously or sequentially against the first end wall 2310 of the pouch. Additionally, the secondary battery assembly 2300 may be heated before, during, or after the end flap 2332, the first tab 2702, and the second tab 2704 are pressed against the pouch 514. In one exemplary embodiment, the end flap 2332, the first tab 2702, and the second tab 2704 are pressed against the first end wall 2310 of the pouch while the secondary battery assembly 2300 is heated at a second pressing temperature for a second pressing time. The second pressing temperature may be, for example, but is not limited to, in the range of 50° C. to 150° C., 70° C. to 150° C., 90° C. to 150° C., 90° C. to 140° C., 100° C. to 150° C., 90° C. to 130° C., 100° C. to 140° C., 110° C. to 150° C., 90° C. to 120° C., 100° C. to 130° C., 110° C. to 140° C., or 120° C. to 150° C. The second pressing time may be, for example, but is not limited to, in the range of 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0171] The pressing and heat treatment steps described above can be performed on the secondary battery assembly 2300 using any suitable pressing fixture(s) and heating system(s) known in the art. For example, a suitable pressing fixture can include a pair of plates oriented parallel to one another, at least one of the plates secured to a drive mechanism that moves the plate toward and away from the other plate to apply a pressing load to the plate against an object placed between the plates. The pressing fixture or a portion thereof can be enclosed or disposed within a temperature controlled environment to heat an object pressed by the pressing fixture to a desired temperature. Additionally, in some embodiments, the secondary battery assembly 2300 can be placed and secured within a clamp, vice, or other pressing device prior to undergoing the pressing and / or heat treatment steps described herein. For example, the secondary battery assembly 2300 can be secured within a clamp that applies pressure in a direction perpendicular to the direction of the pressing force applied during the pressing process to prevent or inhibit deformation of the secondary battery assembly 2300 in a direction perpendicular to the direction of the pressing force. In some embodiments, for example, the secondary battery assembly 2300 is placed in a clamp that applies a compressive force against the base 2302 and cover 2304 (i.e., in the Z direction, as shown in Figures 23-25) before the secondary battery assembly 2300 undergoes the compression processing steps described herein.

[0172] The following embodiments are provided to illustrate various aspects of the present disclosure. The following embodiments are not intended to be limiting, and thus the present disclosure further supports other aspects and / or embodiments not specifically provided below.

[0173] Embodiment 1: A method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, each unit cell of the population of unit cells including an electrode structure, a separator structure, and a counter electrode structure, the method including the steps of: disposing the lithium-containing secondary battery within a pouch defined by an enclosure; trimming the enclosure to form a plurality of flaps including a first side flap extending from the pouch at a first fold line, a second side flap extending from the pouch at a second fold line, and an end flap extending from the pouch at a third fold line; and trimming the first side flap to form a plurality of flaps. attaching the end flap to the pouch by folding each of the first and second side flaps toward and in contact with the pouch about respective first and second fold lines, where a portion of the first side flap extends beyond the pouch to define a first tab and a portion of the second side flap extends beyond the pouch to define a second tab; attaching the end flap to the pouch by folding the end flap toward and in contact with the pouch about a third fold line; and attaching the first and second tabs to the end flap by folding each of the first and second tabs toward and in contact with the end flap.

[0174] Embodiment 2: The method of embodiment 1, wherein the step of attaching the first and second side flaps to the pouch includes the steps of applying adhesive to at least one of the first side flap and the pouch and the second side flap and the pouch, folding the first side flap toward the pouch around a first fold line, folding the second side flap toward the pouch around a second fold line, and pressing the first and second side flaps against the pouch.

[0175] Embodiment 3: The method of embodiment 2, wherein the step of pressing the first and second side flaps against the pouch comprises the step of pressing the first and second side flaps against the pouch while heating at a temperature in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0176] Embodiment 4: The method of embodiment 3, wherein the step of pressing the first and second side flaps against the pouch comprises the step of pressing the first and second side flaps against the pouch while heating at a temperature for a time in the range of 10 seconds to 60 seconds, in the range of 10 seconds to 40 seconds, in the range of 20 seconds to 50 seconds, in the range of 30 seconds to 60 seconds, in the range of 10 seconds to 30 seconds, in the range of 15 seconds to 35 seconds, in the range of 20 seconds to 40 seconds, in the range of 25 seconds to 45 seconds.

[0177] Embodiment 5: The method of any one of the previous embodiments, wherein the step of attaching the end flap to the pouch includes the steps of applying adhesive to at least one of the end flap and the pouch, folding the end flap toward the pouch around the third fold line, and pressing the end flap, the first tab, and the second tab against the pouch after the first tab and the second tab are folded toward and in contact with the end flap.

[0178] Embodiment 6: The method of any one of the preceding embodiments, wherein the step of attaching the first tab and the second tab to the end flap includes the steps of: applying adhesive to at least one of the end flap and each of the first tab and the second tab after the end flap is folded towards and in contact with the pouch; folding the first and second tabs towards and in contact with the end flap; and pressing the end flap, the first tab, and the second tab against the pouch.

[0179] Embodiment 7: The method of embodiment 6, wherein the step of pressing the end flaps, the first tab, and the second tab against the pouch includes the step of pressing the end flaps, the first tab, and the second tab against the pouch while heating at a temperature in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0180] Embodiment 8: The method of embodiment 7, wherein the step of pressing the end flaps, the first tab, and the second tab against the pouch includes the step of pressing the end flaps, the first tab, and the second tab against the pouch while heating at a temperature for a time in the range of 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0181] Embodiment 9: A method according to any one of the preceding embodiments, wherein the step of trimming the enclosure includes trimming the enclosure such that each of the multiple flaps has a width, measured from a respective fold line to a free end of the flap, that is less than or equal to the height of the pouch, such that when each of the multiple flaps is folded to contact the pouch, none of the multiple flaps extends beyond the height of the pouch.

[0182] Embodiment 10: A method according to any one of the preceding embodiments, wherein trimming the enclosure includes trimming the enclosure by die cutting, rotary cutting, reciprocating cutting, laser cutting, fluid jet cutting, or any combination thereof.

[0183] Embodiment 11: The method of any one of the preceding embodiments, wherein the enclosure comprises aluminum, an aluminum alloy, a polymer, a thin film flexible metal, or any combination thereof.

[0184] Embodiment 12: A method of forming a lithium-containing secondary battery disposed within a pouch defined by an enclosure, the lithium-containing battery including a population of unit cells, an electrode bus bar, a counter electrode bus bar, and a first terminal electrically connected to the electrode bus bar, where each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure, where the enclosure includes a plurality of flaps extending outwardly from the pouch, the plurality of flaps including a first side flap extending from the pouch at a first fold line, a second side flap extending from the pouch at a second fold line, and an end flap extending from the pouch at a third fold line, the method including applying an adhesive to at least one of the first side flap and the pouch, at least one of the second side flap and the pouch, and at least one of the end flap and the pouch; and adhering the first side flap to the first fold line. folding an end flap about a third fold line toward the pouch so that a portion of the first side flap extends beyond the pouch to define a first tab; folding a second side flap about a second fold line toward the pouch so that a portion of the second side flap extends beyond the pouch to define a second tab; pressing the first and second side flaps against the pouch; folding the end flap about a third fold line toward and into contact with the pouch; applying adhesive to at least one of the end flap and each of the first and second tabs after the end flap is folded into contact with the pouch; folding the first and second tabs toward and into contact with the end flap to connect the first and second tabs to the pouch; and pressing the end flap, the first tab, and the second tab against the pouch.

[0185] Embodiment 13: The method of embodiment 12, wherein the enclosure includes a first enclosure layer and a second enclosure layer joined to the first enclosure layer, and each flap includes a first surface defined by the first enclosure layer and an opposing second surface defined by the second enclosure layer.

[0186] Embodiment 14: The method of embodiment 13, wherein the step of applying adhesive to at least one of the first side flap and the pouch, the second side flap and the pouch, and the end flap and the pouch includes a step of applying adhesive to at least one of the first surface of the first side flap and the pouch, the first surface of the second side flap and the pouch, and the first surface of the end flap and the pouch, and wherein the step of pressing the first and second side flaps against the pouch includes a step of pressing the first surface of the first side flap and the first surface of the second side flap against the pouch.

[0187] Embodiment 15: The method of embodiment 14, wherein folding the end flap around the third fold line toward the pouch to contact it includes folding the end flap so that a first surface of the end flap contacts the pouch, wherein applying adhesive to at least one of the end flap and the first and second tabs includes applying adhesive to at least one of the second surface of the end flap and each of the first and second tabs, wherein folding the first tab and the second tab toward the end flap to contact it includes folding the first tab and the second tab toward the second surface of the end flap to contact it.

[0188] Embodiment 16: The method of any one of the preceding embodiments, wherein each of the multiple flaps has a width, measured from a respective fold line to a free end of the flap, that is less than or equal to the height of the pouch, such that when each of the multiple flaps is folded into contact with the pouch, none of the multiple flaps extends beyond the height of the pouch.

[0189] Embodiment 17: The method of any one of the preceding embodiments, wherein the step of pressing the first and second side flaps against the pouch comprises pressing the first and second side flaps against the pouch while heating at a first temperature for a first pressing time.

[0190] Embodiment 18: The method according to embodiment 17, wherein the first pressing time is 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0191] Embodiment 19: The method according to embodiment 17, wherein the first temperature is in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0192] Embodiment 20: The method of any one of the preceding embodiments, wherein the step of pressing the end flaps, the first tab, and the second tab against the pouch includes a step of pressing the end flaps, the first tab, and the second tab against the pouch while heating at a second temperature for a second pressing time.

[0193] Embodiment 21: The method according to embodiment 20, wherein the second pressing time is 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0194] Embodiment 22: The method of embodiment 20, wherein the second temperature is in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0195] Embodiment 23: The method of any one of the preceding embodiments, wherein the adhesive comprises an adhesive tape.

[0196] Embodiment 24: The method of any one of the preceding embodiments, wherein the enclosure comprises aluminum, an aluminum alloy, a polymer, a thin film flexible metal, or any combination thereof.

[0197] Embodiment 25: A method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, each unit cell of the population of unit cells including an electrode structure, a separator structure, and a counter electrode structure, the method includes the steps of disposing the lithium-containing secondary battery in a pouch defined by an enclosure, disposing an auxiliary electrode in the pouch such that the auxiliary electrode contacts the lithium-containing secondary battery, performing a buffering process on the lithium-containing secondary battery, thereby transferring carrier ions from the auxiliary electrode to the lithium-containing secondary battery, removing the auxiliary electrode from the pouch after the buffering process, sealing the enclosure with the secondary battery disposed in the pouch after removing the auxiliary electrode from the pouch, and trimming the sealed enclosure. and attaching the first and second side flaps to the pouch by folding each of the first and second side flaps toward and in contact with the pouch, wherein a portion of the first side flap extends beyond the pouch to define a first tab and a portion of the second side flap extends beyond the pouch to define a second tab; attaching the end flap to the pouch by folding the end flap toward and in contact with the pouch; and attaching the first and second tabs to the end flap by folding each of the first and second tabs toward and in contact with the end flap.

[0198] Embodiment 26: The enclosure includes a first enclosure layer and a second enclosure layer joined to the first enclosure layer, and the pouch includes a base defined by the first enclosure layer, a cover opposite the base and defined by the second enclosure layer, a first sidewall extending from the base to the cover, a second sidewall opposite the first sidewall and extending from the base to the cover, a first end wall extending from the first sidewall to the second sidewall and from the base to the cover, and a first end wall opposite the first end wall. and a second end wall extending from the side wall to the second side wall and from the base to the cover, where first and second terminals of the secondary battery extend outwardly from the second end wall, each flap including a first surface defined by a first enclosure layer and an opposing second surface defined by a second enclosure layer, the first side flap extending from the first side wall of the pouch at a first fold line, the second side flap extending from the second side wall of the pouch at a second fold line, and the end flap extending from the first end wall of the pouch at a third fold line, Attaching the second side flap to the pouch includes applying adhesive to at least one of a first surface of the first side flap and the first side wall of the pouch, a first surface of the second side flap and the second side wall of the pouch, and at least one of a first surface of the end flap and the first end wall of the pouch; and folding the first side flap about a first fold line toward and into contact with the first side wall of the pouch, wherein a portion of the first side flap extends beyond the first end wall of the pouch to define a first tab. folding the second side flap about the second fold line toward and into contact with the second side wall of the pouch, with a portion of the second side flap extending beyond the first end wall of the pouch to define a second tab; and pressing the first side flap against the first side wall of the pouch and the second side flap against the second side wall of the pouch while heating at a first temperature for a first pressing time, wherein attaching the end flap to the pouch and the first and second tabs to the end cap comprises:26. The method of embodiment 25, comprising folding the end flap about the third fold line toward and in contact with the first end wall of the pouch, applying adhesive to at least one of the second surface of the end flap and the first surface of each of the first and second tabs after the end flap is folded into contact with the first end wall of the pouch, folding the first tab about the fourth fold line toward and in contact with the second surface of the end flap, folding the second tab about the fifth fold line toward and in contact with the second surface of the end flap, and pressing the end flap, the first tab, and the second tab against the first end wall of the pouch while heating at a second temperature for a second pressing time.

[0199] Embodiment 27: A method of forming a lithium-containing secondary battery including a population of unit cells, an electrode bus bar, a counter bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter bus bar, each unit cell of the population of unit cells including an electrode structure, a separator structure, and a counter electrode structure, the method including disposing the lithium-containing secondary battery within a pouch defined by an enclosure, the enclosure including a first enclosure layer and a second enclosure layer bonded to the first enclosure layer. and a closure layer, the pouch including a base defined by a first enclosure layer, a cover opposite the base and defined by a second enclosure layer, a first sidewall extending from the base to the cover, a second sidewall opposite the first sidewall and extending from the base to the cover, a first end wall extending from the first sidewall to the second sidewall and from the base to the cover, and a second end wall opposite the first end wall and extending from the first sidewall to the second sidewall and from the base to the cover, wherein first and second terminals of the secondary battery are extending outwardly from the second end wall; and trimming the enclosure to form a plurality of flaps within the enclosure, each flap extending outwardly from the pouch at a respective fold line and including a first surface defined by the first enclosure layer and an opposing second surface defined by the second enclosure layer, the plurality of flaps including a first side flap extending from the first side wall of the pouch at the first fold line, a second side flap extending from the second side wall of the pouch at the second fold line, and a third side flap extending from the first end wall of the pouch at the third fold line. applying adhesive to at least one of a first surface of the first side flap and the first side wall of the pouch, at least one of a first surface of the second side flap and the second side wall of the pouch, and at least one of the first surface of the end flap and the first end wall; folding the first side flap about a first fold line toward and into contact with the first side wall of the pouch, wherein a portion of the first side flap extends beyond the first end wall of the pouch to define a first tab;folding the second side flap about the second fold line toward and into contact with the second side wall of the pouch, with a portion of the second side flap extending beyond the first end wall of the pouch to define a second tab; pressing the first side flap against the first side wall of the pouch and pressing the second side flap against the second side wall of the pouch while heating at a first temperature for a first pressing time; folding the end flap about a third fold line toward and into contact with the first end wall of the pouch; applying adhesive to at least one of the second surface of the end flap and the first surface of each of the first and second tabs after contacting the first end wall of the pouch, folding the first tab toward and contacting the second surface of the end flap about a fourth fold line, folding the second tab toward and contacting the second surface of the end flap about a fifth fold line, and pressing the end flap, the first tab, and the second tab against the first end wall of the pouch while heating at a second temperature for a second pressing time.

[0200] Embodiment 28: The method of embodiment 26 or embodiment 27, wherein the step of trimming the enclosure includes a step of trimming the enclosure such that each of the multiple flaps has a width, measured from the respective fold line to the free end of the flap, that is less than or equal to the height of the pouch, such that when each of the multiple flaps is folded to contact the pouch, none of the multiple flaps extends beyond the height of the pouch.

[0201] Embodiment 29: The method of any one of the previous embodiments, wherein the step of pressing the first side flap against the first side wall of the pouch and the second side flap against the second side wall of the pouch comprises applying a pressing force across the first side wall of the pouch and the second side wall of the pouch equal to a pressure of at least 5 pounds per square inch (psi), at least 8 psi, at least 10 psi, at least 15 psi, at least 20 psi, at least 25 psi, at least 30 psi, at least 35 psi, between 5 psi and 50 psi, between 5 psi and 20 psi, between 10 psi and 40 psi, between 5 psi and 15 psi, or between 20 psi and 40 psi.

[0202] Embodiment 30: The method according to any one of the preceding embodiments, wherein the first pressing time is 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0203] Embodiment 31: The method according to any one of the previous embodiments, wherein the first temperature is in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0204] Embodiment 32: The method of any one of the preceding embodiments, wherein pressing the end flap, the first tab, and the second tab against the first end wall of the pouch comprises applying a pressing force equal to a pressure of at least 3 pounds per square inch (psi), at least 4 psi, at least 5 psi, at least 10 psi, at least 15 psi, at least 20 psi, 3 psi to 40 psi, 3 psi to 30 psi, 3 psi to 25 psi, 4 psi to 40 psi, 4 psi to 25 psi, 5 psi to 40 psi, 5 psi to 30 psi, 5 psi to 25 psi, 10 psi to 50 psi, 10 psi to 40 psi, 10 psi to 30 psi, 10 psi to 25 psi, 15 psi to 30 psi, or 20 psi to 35 psi across the first end wall of the pouch.

[0205] Embodiment 33: The method according to any one of the preceding embodiments, wherein the second pressing time is 10 seconds to 60 seconds, 10 seconds to 40 seconds, 20 seconds to 50 seconds, 30 seconds to 60 seconds, 10 seconds to 30 seconds, 15 seconds to 35 seconds, 20 seconds to 40 seconds, or 25 seconds to 45 seconds.

[0206] Embodiment 34: The method according to any one of the previous embodiments, wherein the second temperature is in the range of 50°C to 150°C, 70°C to 150°C, 90°C to 150°C, 90°C to 140°C, 100°C to 150°C, 90°C to 130°C, 100°C to 140°C, 110°C to 150°C, 90°C to 120°C, 100°C to 130°C, 110°C to 140°C, or 120°C to 150°C.

[0207] Embodiment 35: A secondary battery assembly formed using any of the preceding embodiments of the method of forming a lithium-containing secondary battery.

[0208] Embodiment 36: A secondary battery assembly as described in embodiment 35, wherein the electrode assembly of the battery assembly includes a rectangular prism shape.

[0209] Embodiment 37: A secondary battery assembly described in any one of the preceding embodiments, wherein the electrode assembly is enclosed within a volume defined by a constraint.

[0210] Embodiment 38: The electrode assembly is an electrode assembly comprising: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements; (c) alloys or intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, or Cd. The secondary battery assembly of any one of the preceding embodiments, comprising a positive electrode active material selected from the group consisting of oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides, and mixtures, composites, or lithium-containing composites thereof; (d) salts and hydroxides of Sn; (e) lithium titanate, lithium manganate, lithium aluminate, lithium-containing titanium oxides, lithium transition metal oxides, ZnCo2O4; (f) particles of graphite and carbon; (g) lithium metal; and (h) combinations thereof.

[0211] Embodiment 39: A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises an anode active material selected from the group consisting of silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd).

[0212] Embodiment 40: A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises an anode active material selected from the group consisting of alloys and intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements.

[0213] Embodiment 41: A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises an anode active material selected from the group consisting of oxides, carbides, nitrides, sulfides, phosphides, selenides and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, and Cd.

[0214] Embodiment 42: A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises an anode active material selected from the group consisting of oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Si.

[0215] Embodiment 43: A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises a positive electrode active material selected from the group consisting of silicon, oxides and carbides of silicon.

[0216] Embodiment 44: A secondary battery assembly as described in any one of the preceding embodiments, wherein the electrode assembly comprises a positive electrode active material comprising lithium metal.

[0217] Embodiment 45: A secondary battery assembly as described in any one of the preceding embodiments, wherein the electrode assembly comprises a positive electrode active material selected from the group consisting of graphite and carbon.

[0218] Embodiment 46: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises a non-aqueous organic electrolyte within the enclosure.

[0219] Embodiment 47: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises within the enclosure a non-aqueous electrolyte comprising a mixture of a lithium salt and an organic solvent.

[0220] Embodiment 48: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises a polymer electrolyte within the enclosure.

[0221] Embodiment 49: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises a solid electrolyte within the enclosure.

[0222] Embodiment 50: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises, within the enclosure, a solid electrolyte selected from the group consisting of sulfide-based electrolytes.

[0223] Embodiment 51: A secondary battery includes a lithium tin phosphorus sulfide (Li 10 SnP2S 12 ), lithium phosphorus sulfide (β-Li3PS4) and lithium phosphorus sulfide iodide (Li6PS5Cl 0.9 I 0.1 4. The secondary battery assembly of any one of the preceding embodiments, further comprising a solid electrolyte selected from the group consisting of:

[0224] Embodiment 52: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises a polymer-based electrolyte within the enclosure.

[0225] Embodiment 53: A secondary battery assembly described in any one of the preceding embodiments, wherein the secondary battery further comprises a polymer electrolyte within the enclosure selected from the group consisting of PEO-based polymer electrolytes, polymer ceramic composite electrolytes (solid-state), and other polymer ceramic composite electrolytes.

[0226] Embodiment 54: A secondary battery assembly according to any one of the preceding embodiments, wherein the secondary battery further comprises, within the enclosure, a solid electrolyte selected from the group consisting of oxide-based electrolytes.

[0227] Embodiment 55: A secondary battery includes a lithium lanthanum titanate (Li 0.34 La 0.56 TiO3), Al-doped lithium lanthanum zirconate (Li 6.24 La3Zr2Al0.24 O 11.98 ), Ta-doped lithium lanthanum zirconate (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 ) and lithium aluminum titanium phosphate (Li 1.4 Al 0.4 Ti 1.6 3. The secondary battery assembly of any one of the preceding embodiments, further comprising a solid electrolyte selected from the group consisting of (PO4)3).

[0228] Embodiment 56: A secondary battery assembly according to any one of the preceding embodiments, wherein one of the electrode active material and the counter electrode material of the electrode assembly is a cathode active material selected from the group consisting of an intercalation type chemical cathode and a conversion type chemical cathode.

[0229] Embodiment 57: A secondary battery assembly according to any one of the preceding embodiments, wherein one of the electrode active material and the counter electrode material of the electrode assembly is a negative electrode active material comprising an intercalation-type chemical positive electrode material.

[0230] Embodiment 58: A secondary battery assembly according to any one of the preceding embodiments, wherein one of the electrode active material and the counter electrode material of the electrode assembly is a negative electrode active material comprising a conversion type chemistry positive electrode active material.

[0231] Embodiment 59: One of the electrode active material and the counter electrode material of the electrode assembly is S (or a lithiated state Li2S), LiF, Fe, Cu, Ni, FeF2, FeO d F 3.2d , FeF3, CoF3, CoF2, CuF2, NiF2, where 0≦d≦0.5.

[0232] Embodiment 60: A secondary battery assembly described in any one of the preceding embodiments, wherein the electrode structure is one of a positive electrode and a negative electrode, and the counter electrode structure is the other of a positive electrode and a negative electrode, the positive electrode having a positive electrode coulombic capacity, and the negative electrode having a negative electrode coulombic capacity that exceeds the positive electrode coulombic capacity.

[0233] Embodiment 61: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.2:1.

[0234] Embodiment 62: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.3:1.

[0235] Embodiment 63: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.5:1.

[0236] Embodiment 64: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 2:1.

[0237] Embodiment 65: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 3:1.

[0238] Embodiment 66: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 4:1.

[0239] Embodiment 67: A secondary battery assembly as described in embodiment 60, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 5:1.

[0240] Embodiment 68: The method of any one of the preceding embodiments, further comprising the steps of disposing a lithium-containing secondary battery in a pouch defined by the enclosure, disposing an auxiliary electrode in the pouch such that the auxiliary electrode is in contact with the lithium-containing secondary battery, and performing a buffer process on the lithium-containing secondary battery, thereby transferring carrier ions from the auxiliary electrode to the lithium-containing secondary battery.

[0241] Embodiment 69: The method of embodiment 68, further comprising the steps of removing the auxiliary electrode from the pouch after the buffering process, and sealing the enclosure with the secondary battery disposed in the pouch after removing the auxiliary electrode from the pouch.

[0242] Embodiment 70: The method of embodiment 68 or embodiment 69, wherein the auxiliary electrode comprises a first separator layer comprising an ion-permeable material, a conductive layer comprising a conductive material, the conductive layer having a first surface in contact with the first separator layer and a second surface opposite the first surface, a group of carrier ion supply layers disposed on the second surface of the conductive layer, each carrier ion supply layer comprising a material that supplies lithium ions to an electrode active material layer of a lithium-containing secondary battery, and a second separator layer comprising an ion-permeable material and in contact with the carrier ion supply layer.

[0243] Embodiment 71: The method of embodiment 70, wherein the second surface of the conductive layer includes a first region disposed at a first end of the conductive layer, a second region disposed at a second end of the conductive layer opposite the first end, and a third region disposed between the first and second regions, wherein one carrier ion supply layer is disposed in the first region and another carrier ion supply layer is disposed in the second region.

[0244] Embodiment 72: The method of embodiment 71, wherein the second separator layer is in contact with a third region of the second surface of the conductive layer.

[0245] Embodiment 73: The method of embodiment 70 or embodiment 71, wherein the first region, the second region, and the third region are disposed along the length of the conductive layer.

[0246] Embodiment 74: The method of any one of embodiments 70-73, wherein the first separator layer and the second separator layer are mechanically bonded around at least a portion of the periphery of the first separator layer and the second separator layer.

[0247] Embodiment 75: The method of any one of embodiments 70 to 74, wherein the first separator layer and the second separator layer are formed from a continuous separator material, the first separator layer comprising a first portion of the continuous separator material, and the second separator layer comprising a second portion of the continuous separator material, the second portion being folded over the first portion to contact the surface of the carrier ion supply layer.

[0248] Embodiment 76: The method of embodiment 75, wherein the continuous separator material has a thickness in the range of about 0.01 millimeters to about 1 millimeter.

[0249] Embodiment 77: The method of embodiment 76, wherein the thickness of the continuous separator material is about 0.025 millimeters.

[0250] Embodiment 78: The method of any one of embodiments 70 to 77, wherein the first separator layer and the second separator layer have a thickness ranging from about 0.01 millimeters to about 1 millimeter.

[0251] Embodiment 79: The method of any one of embodiments 70-78, wherein the second separator layer has a thickness of about 0.025 millimeters.

[0252] Embodiment 80: The method of any one of embodiments 70 to 79, wherein the conductive layer comprises one of copper and aluminum, or an alloy of copper and aluminum.

[0253] Embodiment 81: The method of any one of embodiments 70-80, wherein the conductive layer comprises copper.

[0254] Embodiment 82: The method of any one of embodiments 70 to 81, wherein the conductive layer has a thickness ranging from about 0.01 millimeters to about 1 millimeter.

[0255] Embodiment 83: The method of any one of embodiments 70 to 82, wherein the conductive layer has a thickness of about 0.1 millimeters.

[0256] Embodiment 84: The method of any one of embodiments 70 to 83, wherein the carrier ion supply layer has a thickness in the range of about 0.05 millimeters to about 1 millimeter.

[0257] Embodiment 85: The method of any one of embodiments 70 to 84, wherein the carrier ion supply layer has a thickness of about 0.15 millimeters.

[0258] Embodiment 86: The method of any one of embodiments 70-85, wherein the carrier ion supply layer provides a source of lithium ions.

[0259] Embodiment 87: The method of any one of embodiments 70 to 86, wherein the carrier ion supply layer is cold welded to the second surface of the conductive layer.

[0260] Embodiment 88: The method of any one of embodiments 70 to 87, wherein the auxiliary electrode comprises a conductive tab coupled to the second surface of the conductive layer, the conductive tab comprising a conductive material.

[0261] Embodiment 89: The method of any one of embodiments 88, wherein the conductive tab includes a first end coupled to the conductive layer and a second end away from the first end protruding from the conductive layer.

[0262] Embodiment 90: The method of any one of embodiment 88 or embodiment 89, wherein the conductive tab comprises one of nickel, copper, aluminum, or an alloy of copper, nickel and aluminum.

[0263] Embodiment 91: The method of any one of embodiment 88 or embodiment 89, wherein the conductive tab comprises nickel.

[0264] This written specification uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal words of the claims, or if they include equivalent structural elements with differences that do not differ insubstantially from the literal words of the claims.

Claims

1. A method for forming a battery, The aforementioned method, Positioning the electrode assembly within an enclosure having a flap extending from the internal space of the enclosure that houses the electrode assembly, wherein the electrode assembly includes an electrode separated from the counter electrode by a separator structure. The enclosure is trimmed to form a flap that includes a first side flap extending from the enclosure along a first fold, a second side flap extending from the enclosure along a second fold, and an end flap extending from the enclosure along a third fold. (a) the first side flap is folded toward the enclosure and in contact with it around the first fold line such that a portion of the first side flap extends beyond the enclosure and defines a first tab, and (b) the first side flap is folded toward the enclosure and in contact with it around the second fold line such that a portion of the second side flap extends beyond the enclosure and defines a second tab, thereby causing the first side flap to be in at least partial contact with the enclosure. By folding the end flap toward the enclosure around the third fold line and bringing it into contact with the enclosure, the end flap is brought into at least partial contact with the enclosure, and (i) By bending the first tab toward the end flap and bringing it into contact with the end flap, the first tab is brought into at least partial contact with the end flap; (ii) By bending the second tab toward the end flap, the second tab is brought into at least partial contact with the end flap. A method that includes this.

2. Bringing the first side flap and the second side flap into contact with the enclosure means that Apply the adhesive to (a) at least one of the first side flap and the internal space of the enclosure, and (b) at least one of the second side flap and the enclosure. Folding the first side flap toward the enclosure around the first fold line, Folding the second side flap toward the enclosure around the second fold line, and (i) Pressing the first side flap against the enclosure, and (ii) Pressing the second side flap against the enclosure. including, The method according to claim 1.

3. The adhesive includes an adhesive strip, a liquid adhesive, or any combination thereof. The method according to claim 2.

4. (A) The pressing includes clamping or using a vise, and / or (B) The method includes using a hot press, The method according to claim 2.

5. The adhesive includes adhesive tape. The method according to claim 2.

6. Pressing the first side flap and the second side flap against the enclosure includes pressing them at a temperature in the range of 50 degrees Celsius to 150 degrees Celsius. The method according to claim 2.

7. Pressing the first side flap and the second side flap against the enclosure includes pressing them for a period of time ranging from 10 to 60 seconds. The method according to claim 3.

8. Bringing the end flap into contact with the enclosure means Apply adhesive to at least one of the end flap and the enclosure. Folding the end flap toward the enclosure around the third fold line, (i) pressing the end flap, (ii) the first tab, and (iii) the second tab against the enclosure, The pressing is performed after the first tab and the second tab are bent toward the end flap and come into contact with the end flap. including, The method according to claim 1.

9. Attaching the first tab and the second tab to the end flap is, After the end flap is bent toward the enclosure and in contact with the enclosure, (a) adhesive is applied to the end flap and (b) at least one of the first tab and the second tab. Bending the first tab and the second tab toward the end flap and bringing them into contact, (a) Pressing the end flap, (b) the first tab, and (c) the second tab against the enclosure. including, The method according to claim 1.

10. Trimming the enclosure includes trimming the enclosure such that the width measured from each fold line of the flap to the free edge of the flap is less than or equal to the height of the enclosure, and that when each flap is folded to contact the enclosure, none of the flaps extend beyond the height of the enclosure. The method according to claim 1.

11. Trimming the enclosure includes trimming by die cutting, rotary cutting, reciprocating cutting, laser cutting, fluid jet cutting, or any combination thereof. The method according to claim 1.

12. The enclosure includes polymers, resins, single metals, metal alloys, composite materials, or any combination thereof. The method according to claim 1.

13. The enclosure includes a first enclosure layer and a second enclosure layer bonded to the first enclosure layer, and each of the flaps includes a first surface defined by the first enclosure layer and an opposing second surface defined by the second enclosure layer. The method according to claim 1.

14. Pressing (A) the first side flap and (B) the second side flap against the enclosure includes pressing while heated at a first temperature for a first pressing time, and pressing (a) the end flap, (b) the first tab, and (c) the second tab against the enclosure includes pressing while heated at a second temperature for a second pressing time. The method according to claim 1.

15. The electrode assembly has a volume defined by a casing configured to promote the distribution of the electrolyte, and the casing is a restraining body. The method according to claim 1.

16. The enclosure is sized and shaped to match the size and shape of the outer surface of the electrode assembly, respectively. The method according to claim 1.

17. (A) The enclosure is airtight, (B) The enclosure is liquidtight, or (C) Any combination thereof. The method according to claim 1.

18. The method described above is performed at least partially in a controlled environment. The method according to claim 1.

19. Further including controlling temperature and / or pressure, The method according to claim 18.

20. The material of the enclosure includes aluminum, aluminum alloy, or any combination thereof. The method according to claim 1.

21. Before trimming the enclosure to form the aforementioned flap, Positioning the auxiliary electrode within the enclosure, A buffering process is performed to transfer carrier ions from the auxiliary electrode to the electrode assembly. Removing the auxiliary electrode from the enclosure after the buffering process, and The electrode assembly is positioned within the enclosure and the enclosure is sealed. Further including, The method according to claim 1.

22. The auxiliary electrode partially surrounds the electrode assembly. The method according to claim 21.

23. The further includes performing buffering to form at least partially a solid electrolyte interface (SEI) on the surface of the anode active material of the electrode assembly, The method according to claim 21.

24. Pressing (a) the end flap, (b) the first tab, and (c) the second tab against the enclosure includes pressing at a temperature in the range of 50°C to 150°C. The method according to claim 22.

25. Pressing (a) the end flap, (b) the first tab, and (c) the second tab against the enclosure includes pressing for a period of time ranging from 10 to 60 seconds. The method according to claim 23.

26. The enclosure includes a first enclosure layer and a second enclosure layer bonded to the first enclosure layer, the enclosure includes a base defined by the first enclosure layer, a cover located on the opposite side of the base and defined by the second enclosure layer, a first side wall extending from the base to the cover, a second side wall located on the opposite side of the first side wall and extending from the base to the cover, a first end wall extending from the first side wall to the second side wall and from the base to the cover, and a second end wall located on the opposite side of the first end wall and extending from the first side wall to the second side wall and from the base to the cover. The method according to claim 1.

27. The electrode assembly is operably coupled to a first terminal and a second terminal, each of which extends outward from the second end wall. The method according to claim 26.

28. Pressing (a) the end flap, (b) the first tab, and (c) the second tab against the first end wall includes applying a pressing force equal to a pressure of 3 pounds per square inch across the first end wall. The method according to claim 26.

29. The aforementioned battery is a lithium-containing secondary battery. The method according to claim 1.

30. The battery is configured to perform an initial formation process different from subsequent charge and discharge cycles. The method according to claim 29.

31. The electrode assembly is operably coupled to the electrode busbar and the counter electrode busbar. The method according to claim 1.

32. The first terminal is electrically connected to the electrode busbar, and the second terminal is electrically connected to the counter electrode busbar. The method according to claim 31.

33. A battery manufactured according to the method of any one of claims 1 to 32.

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