Battery cell formation

Abstract

The compression fixture includes a base and a plurality of compression plate sets coupled to the base. Each compression plate set includes a stationary compression plate, a movable compression plate, and at least one spring coupled to the movable compression plate. The movable compression plate is movable relative to the stationary compression plate between a first position and a second position in which the movable compression plate is disposed further from the stationary compression plate than the first position. The stationary compression plate and the movable compression plate define a battery receptacle therebetween for receiving a lithium-containing secondary battery. The spring biases the movable compression plate toward the stationary compression plate such that a compressive force is applied to the lithium-containing secondary battery when disposed in the battery receptacle. The compression fixture can be incorporated into a cell formation system for a lithium-containing secondary battery.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 325,928, 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 cell formation systems for lithium-containing secondary batteries. [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] Silicon has become a promising candidate to replace carbonaceous materials as anodes due to its high specific capacity. For example, a graphite anode formed from LiC6 can have a specific capacity of about 370 milliampere-hours per gram (mAh / g), while a Li 15 Crystalline silicon anodes formed from Si4 can have a specific capacity of about 3600 mAh / g, nearly 10 times higher than graphite anodes. However, the use of silicon anodes has been limited due to the large volume change (e.g., 300%) of silicon when Li carrier ions are inserted into the silicon anode. This volume increase, together with the cracking and pulverization associated with charge and discharge cycles, has limited the practical use of silicon anodes. In addition, the use of silicon anodes has been limited due to their poor initial coulombic efficiency (ICE), which leads to capacity loss during the initial formation of secondary batteries utilizing silicon anodes.

[0005] After the lithium-containing secondary batteries are assembled, the assembled batteries are typically subjected to a formation process. During the formation process, the batteries are slowly charged and discharged one or more times. At least some known formation processes include a pre-lithiation process to add lithium to the batteries. These formation processes are typically performed by large-scale centralized systems. Such systems include a central control center connected to all the batteries undergoing the formation process. The central control center directly controls the charging, discharging, and (where applicable) pre-lithiation of all the batteries to which it is connected. To control the formation process and enable the distribution of power to a large number of batteries, the central control center is a relatively large and expensive system that uses a significant amount of power, occupies a significant amount of space, and utilizes a large number of wires to connect to all of the batteries undergoing formation. Summary of the Invention

[0006] One embodiment includes a cell formation system for lithium-containing secondary batteries. Each lithium-containing secondary battery includes a population of unit cells, an electrode bus bar, a counter electrode bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter electrode bus bar. Each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The cell formation system includes a compression fixture and a loading mechanism. The compression fixture includes a base and a plurality of compression plate sets coupled to the base. Each compression plate set includes a stationary compression plate, a movable compression plate movable relative to the stationary compression plate between a first position and a second position, and at least one spring operably coupled to the movable compression plate. The movable compression plate is disposed further from the stationary compression plate at the second position than at the first position. The stationary compression plate and the movable compression plate define a battery receptacle therebetween for receiving a lithium-containing secondary battery. The at least one spring biases the movable compression plate toward the fixed compression plate to apply a compressive force to the lithium-containing secondary battery when disposed in the battery receptacle, and the loading mechanism includes at least one plate spreader operable to move the movable compression plate away from the fixed compression plate for loading and unloading the lithium-containing secondary battery in the battery receptacle.

[0007] Another embodiment includes a compression fixture for lithium-containing secondary batteries. Each lithium-containing secondary 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. Each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The compression fixture includes a base and a plurality of compression plate sets coupled to the base. Each compression plate set includes a fixed compression plate, a movable compression plate, and at least one spring coupled to the movable compression plate. The movable compression plate is movable relative to the fixed compression plate between a first position and a second position in which the movable compression plate is disposed further from the fixed compression plate than the first position. The fixed compression plate and the movable compression plate define a battery receptacle therebetween for receiving a lithium-containing secondary battery. The at least one spring biases the movable compression plate toward the fixed compression plate to apply a compressive force to the lithium-containing secondary battery when disposed in the battery receptacle.

[0008] Another embodiment includes a method of manufacturing a lithium-containing secondary battery. Each lithium-containing secondary battery includes a population of unit cells, an electrode bus bar, a counter electrode bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter electrode bus bar. Each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The method includes moving a movable compression plate of a compression plate set from a first position to a second position. The compression plate set includes a fixed compression plate, a movable compression plate, and at least one spring biasing the movable compression plate toward the fixed compression plate. The fixed compression plate and the movable compression plate define a battery receptacle therebetween. The movable compression plate is disposed further from the fixed compression plate in the second position than in the first position. The method further includes placing a lithium-containing secondary battery in the battery receptacle and moving the movable compression plate toward and engaging the lithium-containing secondary battery such that the lithium-containing secondary battery is compressed between the fixed compression plate and the movable compression plate.

[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 extended 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 an 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] FIG. 1 is a block diagram of an exemplary cell formation system. [Diagram 23] FIG. 23 is a perspective view of an exemplary battery tray for the cell formation system of FIG. [Figure 24] 23 is a perspective view of an exemplary forming base for the cell forming system of FIG. 22. [Diagram 25] 25 is an enlarged view of the connector group of the forming base of FIG. 24. [Figure 26] 25 is a side view of the battery tray of FIG. 23 positioned to be attached to the forming base of FIG. 24 to form a forming assembly. [Figure 27] 25 is a partial view of the battery tray of FIG. 23 positioned on the forming base of FIG. 24 with the assembly connectors aligned. [Figure 28] 25 is a partial view of the battery tray of FIG. 23 lowered onto the forming base of FIG. 24. [Figure 29] 25 is a partial view of the battery tray of FIG. 23 lowered onto the forming base of FIG. 24 with the assembly connector engaged. [Diagram 30] FIG. 1 is a block diagram of an exemplary cell formation system for a lithium-containing secondary battery. [Diagram 31] FIG. 31 is a block diagram of an exemplary cell forming cluster for use in the cell forming system of FIG. 30. [Diagram 32] FIG. 32 is a block diagram of an exemplary pre-lithiation module for use in the formation cluster of FIG. [Diagram 33] FIG. 33 is a simplified circuit diagram of an exemplary embodiment of a switched-capacitor circuit for use in the pre-lithiation module of FIG. [Figure 34A] 34 is a graph of a series of PFM control pulses applied to the switches of the switched capacitor circuit of FIG. 33 as a function of time. [Figure 34B] 34B is a graph of the resulting current through the auxiliary electrode in response to the control pulse of FIG. 34A as a function of time. [Diagram 35] FIG. 33 is a circuit diagram of an exemplary embodiment of a switched-capacitor circuit for use in the pre-lithiation module of FIG. [Figure 36A] 1 is a graph of a buffer current for use as part of an exemplary pre-lithiation profile. [Figure 36B] 1 is a graph of pulse duration for an exemplary prelithiation profile. [Figure 36C] 1 is a graph of the number of pulses for an exemplary pre-lithiation profile. [Figure 37A] FIG. 36C is a graph of the cathode-anode voltage and the cathode-auxiliary electrode voltage as a function of time when prelithiating using the prelithiation profiles of FIGS. 36A-36C. [Figure 37B] FIG. 36C is a graph of buffer current as a function of time when prelithiating using the prelithiation profiles of FIGS. 36A-36C. [Figure 38] FIG. 1 is a perspective view of a cell formation system including a compression fixture according to one suitable embodiment of the present disclosure. [Figure 39] FIG. 39 is a perspective view of a battery tray of the cell formation system of FIG. [Diagram 40] FIG. 39 is a partial exploded view of the components of the compression fastener shown in FIG. 38. [Diagram 41] FIG. 39 is a top perspective view of the base of the compression fixture shown in FIG. 38. [Diagram 42] FIG. 42 is a bottom perspective view of the compression fixture base shown in FIG. 41. [Diagram 43] FIG. 42 is an enlarged perspective view of the compression fixture base shown in FIG. 41. [Diagram 44] FIG. 39 is an enlarged perspective view of the compression fixture shown in FIG. 38. [Diagram 45] FIG. 39 is an enlarged top view of the compression fixture shown in FIG. 38 showing the movable compression plate in a first position. [Diagram 46] 39 is another enlarged top view of the compression fixture shown in FIG. 38 showing the movable compression plate in a second position. [Figure 47] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 48] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 49] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 50] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 51] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 52] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 53] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 54] 39A-39C are perspective and top views of the compression fixture shown in FIG. 38 illustrating a sequence of steps for loading a secondary battery into a battery receptacle of the compression fixture. [Figure 55] FIG. 39 is a front view of a stationary compression plate suitable for use with the compression fixture shown in FIG. 38. [Figure 56] FIG. 56 is a rear view of the fixed compression plate shown in FIG. [Figure 57] FIG. 39 is a front view of a movable compression plate suitable for use with the compression fixture shown in FIG. 38. [Figure 58]FIG. 58 is a rear view of the movable compression plate shown in FIG. 57. [Figure 59] FIG. 39 is a perspective view of a compression fixture and loading mechanism of the cell formation system shown in FIG. 38. [Figure 60] FIG. 60 is an enlarged perspective view of the loading mechanism and compression fixture shown in FIG. 59. [Figure 61] FIG. 60 is another enlarged perspective view of the loading mechanism and compression fixture shown in FIG. 59. [Figure 62] FIG. 60 is a side view of the loading mechanism and compression fixture shown in FIG. 59. [Figure 63] FIG. 60 is an enlarged perspective view of a portion of the loading mechanism shown in FIG. 59. [Figure 64] FIG. 60 is another enlarged perspective view of a portion of the loading mechanism shown in FIG. 59. [Figure 65] FIG. 60 is another enlarged perspective view of a portion of the loading mechanism shown in FIG. 59. [Figure 66] 1 is a flowchart of an exemplary method for compressing a lithium-containing secondary battery in accordance with one suitable embodiment. 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 including 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, "macroporous" may refer to materials that contain pores having diameters greater than about 50 nanometers, unless the context clearly indicates otherwise.

[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 The embodiments of the present disclosure provide a distributed formation process in which modern electronic devices and distributed embedded network strategies are adopted. Thus, instead of a centralized system that requires a dedicated connection to every battery undergoing a formation process and controls the formation process of hundreds or thousands of batteries, the formation process in the exemplary embodiments of the present disclosure is distributed among smaller clusters, each of which directly handles the formation process of the battery to which it is connected. These embodiments can simplify the construction of the formation system by requiring a less powerful central controller and less interconnection wiring, while allowing the formation processing system to be more easily scaled and physically distributed to desired locations.

[0042] Some embodiments of the present disclosure may provide advantages such as mitigation or amelioration of poor ICE associated with silicon-based anodes in secondary batteries utilizing an auxiliary anode electrochemically coupled with the secondary battery to provide additional carrier ions during and / or after initial battery formation. The use of the auxiliary anode mitigates the initial loss of carrier ions in the secondary battery during initial formation, thereby providing the technical advantage of, for example, increasing the capacity of the secondary battery after formation. Furthermore, the introduction of additional carrier ions after battery formation mitigates the cycle-based loss of carrier ions typically lost through secondary reactions, thereby providing the technical advantage of reducing capacity loss per cycle in the secondary battery. Still further, the introduction of additional carrier ions after battery formation improves the cycle performance of the secondary battery by maintaining the anode of the secondary battery at a lower potential voltage upon discharge since the anode contains additional carrier ions. In some embodiments, the auxiliary anode is removed from the secondary battery after formation, thereby providing the technical advantage of increasing the energy density of the battery.

[0043] 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.

[0044] 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 preferred embodiments 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.

[0045] 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.

[0046] 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.

[0047] 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%.

[0048] 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.

[0049] 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 .

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The cathode active material layer 106 can be an intercalation-type chemically active material, a conversion chemically active material, or a combination thereof.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 ).

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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 less than 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 0.1 to 0.5 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.

[0072] 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.

[0073] 4 shows 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 ).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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%.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] In some embodiments, the separator layer 108 may include a solid lithium-ion conducting ceramic, such as a lithium-filled garnet.

[0086] 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%.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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 .

[0097] 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.

[0098] 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 in 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 a carrier ion-containing form of any of the aforementioned materials used for the cathode active material layer 106 and / or the anode active material layer 104 (see FIG. 2). 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 and the secondary battery 100, which may be referred to as an auxiliary subassembly 516 (see FIG. 6), 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 covered by the enclosure 504 and a conductive tab 508-1 partially exposed by the enclosure, as depicted in FIG. 5.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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 major surfaces 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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).

[0122] 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).

[0123] 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 in a direction away from the pouch 514 along the Y-axis direction.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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 in its final form 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.

[0135] 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.

[0136] 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 .

[0137] 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).

[0138] 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).

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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).

[0144] 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.

[0145] 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.

[0146] 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 its final form to enclose secondary battery 100 for use.

[0147] 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).

[0148] 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.

[0149] 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.

[0150] In some embodiments, one or more steps of the forming process performed on the secondary battery 100 discussed above may be performed using a battery tray and a forming base removably attachable to the battery tray.

[0151] 22 is a block diagram of an exemplary cell formation system 2200 for lithium-containing secondary batteries, such as secondary battery 100. System 2200 includes a battery tray 2202, a forming base 2204, a loading station 2206, a charging station 2208, and a forming station 2210. Battery tray 2202 and forming base 2204, when attached, form a forming assembly 2209. Other embodiments do not include charging station 2208, and batteries to be processed by cell formation system 2200 may be charged using any suitable charging system.

[0152] The battery tray 2202 includes battery slots 2212 and a first assembly connector 2213. Each battery slot 2212 is configured (e.g., sized and shaped) to receive and hold a secondary battery 100. In an exemplary embodiment, each battery slot 2212 is configured to receive only one secondary battery 100, although in other embodiments, each battery slot may be configured to receive two or more batteries. In one exemplary embodiment, the battery tray 2202 includes 120 battery slots 2212 arranged in three rows of 40 battery slots. Other embodiments include more or fewer battery slots 2212 arranged in more or fewer rows. Openings are defined in the bottom of the battery tray 2202 at locations corresponding to the battery slots 2212 to allow the first terminal 124, the second terminal 125, and the conductive tab 508-1 to extend through the bottom of the battery tray when the secondary battery 100 is positioned in the battery slot 2212.

[0153] The forming base 2204 is designed with a similar size and shape to the battery tray 2202 and is configured to removably attach to the battery tray. The forming base 2204 includes a connector group 2214, a pre-lithiated module 2216, and a second assembly connector 2218. Each connector group 2214 is configured to make an electrical connection to the conductive tab 508-1 and one of the first terminal 124 and the second terminal 125 of the different secondary battery 100 when the battery tray 2202 with a secondary battery loaded therein is attached to the forming base. One of the first terminal 124 and the second terminal 125 of the different secondary battery 100 to which the connector group 2214 connects is a negative terminal. In other embodiments, each connector group 2214 is configured to make an electrical connection to the conductive tab 508-1, the first terminal 124, and the second terminal 125 of a different secondary battery 100 when the battery tray 2202 with the secondary battery loaded therein is attached to the forming base 2204.

[0154] Each pre-lithiation module 2216 is electrically connected to a different one of the connector groups 2214 and configured to diffuse lithium into electrode active materials of the secondary batteries 100 connected to the connector groups 2214 to which the pre-lithiation module 2216 is electrically connected. In other embodiments, each pre-lithiation module 2216 is electrically connected to more than one of the connector groups 2214 and configured to diffuse lithium into electrode active materials of the secondary batteries 100 connected to the two or more connector groups 2214 to which the pre-lithiation module 2216 is electrically connected. In one example, the pre-lithiation module 2216 is a switched capacitor circuit. In another example, the pre-lithiation module 2216 includes a resistor electrically connected between the conductive tab 508-1 and one of the first terminal 124 and the second terminal 125, and a circuit that interrupts the connection when the voltage drops to 1.5V (indicating completion of the buffering process). Other embodiments include any other suitable pre-lithiation module 2216.

[0155] The second assembly connector 2218 is configured to matingly engage with the first assembly connector 2213 to mechanically connect the battery tray 2202 to the forming base 2204. In one exemplary embodiment, the first assembly connector 2213 is a rectangular opening through the bottom of the battery tray 2202 and the second assembly connector 2218 is a rotatable T-shaped connector extending from the forming base 2204. In a first orientation, the second assembly connector 2218 can pass through the rectangular opening of the first assembly connector 2213 to allow the battery tray 2202 to be placed in a predetermined position on the forming base 2204. When the second assembly connector 2218 is rotated to a second position (e.g., 90 degrees from the first position), the second assembly connector 2218 cannot pass through the rectangular opening of the first assembly connector 2213. Thus, after the battery tray 2202 is placed in place on the forming base 2204, the second assembly connector 2218 is rotated to a second position to lock the battery tray 2202 and forming base 2204 together within the forming assembly 2209. Other embodiments may use other connection systems for the first and second assembly connectors 2213, 2218.

[0156] The loading station 2206, the charging station 2208, and the forming station 2210 are stations for loading the batteries 100 into the battery tray 2202, charging the batteries in the battery tray, and buffering the batteries in the forming assembly 2209, respectively. In the loading station 2206, the secondary batteries 100 are typically loaded into the battery tray 2202 by a loading mechanism (e.g., loading mechanism 3860 shown in FIG. 38). In other embodiments, the secondary batteries 100 are loaded into the battery tray 2202 by a human operator. The charging station 2208 is configured to receive the battery tray 2202 loaded with the secondary batteries 100, store the loaded battery tray, and charge the batteries 100 in the battery tray. The forming station 2210 is configured to receive a forming assembly 2209 including a battery tray 2202 loaded with a charged secondary battery 100 and store the forming assembly while lithium is diffused into the electrode active material of the secondary battery in the battery tray by a pre-lithiation module 2216. Some embodiments also include a loading station (not shown) where the battery tray 2202 is mounted to the forming base 2204. The battery tray 2202 and forming assembly 2209 can move between the loading station 2206, the charging station 2208, the forming station 2210, and the loading station on a conveyor belt or any other suitable transport system.

[0157] The charging station 2208 includes a rack or shelving system for storing the battery trays 2202 as well as electrical connections for providing power to the battery trays to charge the secondary batteries 100 therein. In some embodiments, the charging station includes charging circuitry for controlling the charging of the secondary batteries 100, while in other embodiments the charging circuitry is included within the battery trays 2202 or forming base 2204. In some embodiments, the charging station 2208 also includes communications connections that allow one or more remote computing devices to control and / or monitor the charging of the secondary batteries 100 at the charging station 2208.

[0158] The forming station 2210 includes a rack or shelving system for storing the forming assemblies 2209, as well as electrical connections for providing power to the forming process. In some embodiments, the forming station 2210 also includes communication connections that allow one or more remote computing devices to control and / or monitor the forming process at the forming station 2210.

[0159] FIG. 23 is a perspective view of an exemplary battery tray that may be used as the battery tray 2202 in the cell formation system 2200 (shown in FIG. 22). The battery tray 2202 includes sides 2300 connected to and extending above a base 2302. In the exemplary embodiment, the battery tray 2202 includes four sides 2300 of approximately equal length, height, and thickness. In other embodiments, the battery tray may include more or fewer sides 2300 and / or the sides may vary in one or more of their dimensions. The exemplary battery tray 2202 includes 120 battery slots 2212 arranged in three columns 2304 of 40 slots each. Other embodiments may include more or fewer total slots 2212 arranged in more or fewer rows 2304. At least one opening (not shown in FIG. 23) is defined through the base 2302 at the location of each slot 2212 to allow the conductive tabs 508-1, the first terminals 124, and the second terminals 125 to extend from the slots 2212 through the base of the battery tray 2202 to a location accessible from the underside 2306 of the battery tray's base. The battery tray 2202 includes six first assembly connectors 2213 (not shown in FIG. 23) for matingly engaging with six corresponding second assembly connectors 2218 of the formed base 2204 to mechanically connect the battery tray 2202 to the formed base 2204. Other embodiments may include more or fewer first assembly connectors 2213 and second assembly connectors 2218.

[0160] FIG. 24 is a perspective view of an exemplary forming base that may be used as the forming base 2204 in the cell forming system 2200 (shown in FIG. 22). The forming base 2204 includes as many connector groups 2214 as the battery trays 2202 have battery slots 2212. Three connector groups 2214 are shown in FIG. 25. The exemplary forming base 2204 includes six second assembly connectors 2218 (three on each side, only one visible in FIG. 24) for mating engagement with the first assembly connectors 2213 of the battery trays 2202 to mechanically connect the battery trays 2202 to the forming base 2204.

[0161] FIG. 26 is a side view of the battery tray 2202 positioned to attach to the forming base 2204 to form a forming assembly 2209. FIGS. 27-29 show the process of engaging one of the second assembly connectors 2218 of the forming base 2204 with one of the first assembly connectors 2213 of the battery tray 2202. During connection of the battery tray 2202 to the forming base 2204, the same process will occur for each first assembly connector 2213 and second assembly connector 2218. As shown in FIG. 27, the battery tray 2202 is positioned on the forming base 2204 with the first assembly connector 2213 aligned over the second assembly connector 2218. In this embodiment, the first assembly connector 2213 is a rectangular opening and the second assembly connector 2218 includes a rotatable rectangular bar 2700 supported above the base 2702 by a post 2704. The rectangular bar 2700 is sized to fit through a rectangular opening in the first assembly connector 2213, and the posts 2704 are sized to be approximately the same height as the thickness of the battery tray base 2302, or slightly greater above the base 2702. When starting to assemble the forming assembly 2209, the second assembly connector 2218 is oriented with the rectangular bar 2700 in a first orientation that will allow it to pass through the rectangular opening in the first assembly connector 2213 and connect the battery tray 2202 and forming base 2204 when the battery tray 2202 is lowered (or the forming base 2204 is raised). The forming base 2204 also has a group of alignment posts 2706 (only one of which is shown in FIG. 27) that correspond to alignment holes 2708 in the battery tray 2202. When the battery tray 2202 is positioned on the forming base 2204, the alignment posts 2706 pass into the alignment holes 2708 to facilitate aligning the forming base 2204 and the battery tray 2202 and to facilitate limited movement of the battery tray 2202 relative to the forming base 2204 in a plane parallel to the base 2702.

[0162] In FIG. 28, the battery tray 2202 has been lowered onto the forming base 2204 and the rectangular bar 2700 of the second assembly connector 2218 has passed through the rectangular opening of the first assembly connector 2213. The rectangular bar 2700 is still in the first orientation at this stage and the battery tray 2202 can be lifted and removed from the forming base 2204. In FIG. 29, the rectangular bar 2700 has been rotated to a second orientation. In the second orientation, the rectangular bar 2700 of the second assembly connector 2218 cannot pass through the opening of the first assembly connector 2213, thereby securing the battery tray 2202 to the forming base 2204. The second orientation is approximately 90 degrees from the first orientation, but the two orientations can differ by any angle sufficient to allow passage of the rectangular bar 2700 through the opening in the first assembly connector 2213 in the first orientation and to prevent passage of the rectangular bar 2700 through the opening in the first assembly connector 2213. Other embodiments may use any other suitable types of connectors for the first and second assembly connectors.

[0163] Described below is one exemplary method of cell formation using cell formation system 2200. It should be understood that cell formation system 2200 may also be used for other methods of cell formation.

[0164] First, a group of lithium-containing secondary batteries 100 are loaded into the battery tray 2202. Each battery 100 is loaded into a different battery slot 2212 having a conductive tab 508-1, a first terminal 124, and a second terminal 125 extending through the battery tray base 2302 to a position accessible from the underside of the battery tray base. The battery tray 2202 is then transported to a charging station 2208, where the lithium-containing secondary batteries 100 in the battery tray are charged. The battery tray 2202 is removed from the charging station 2208, and the forming base 2204 is attached to the battery tray from the underside of the battery tray base 2302 to form a forming assembly 2209. The forming assembly 2209 is transported to the forming station 2210, where the lithium-containing secondary batteries 100 in the forming assembly 2209 are pre-lithiated using the pre-lithiated module 2216. The forming base 2204 is removed from the battery tray 2202 after pre-lithiation is completed. One or more additional processes may be performed on the lithium-containing secondary batteries 100 in the battery tray 2202. The forming base 2204 is returned for reuse while the additional processes are performed. Thus, additional populations of lithium-containing secondary batteries 100 can be loaded into additional battery trays 2202, and the above process can be repeated with the additional battery trays 2202 and forming bases 2204.

[0165] In some embodiments, the formation process is performed by a distributed formation system (which may include cell formation system 2200), in which each secondary battery 100 is connected to a separate formation cluster that performs the formation process for the secondary battery 100 to which it is connected. In embodiments using cell formation system 2200, a separate formation cluster for each secondary battery 100 may be included in formation base 2204. In such embodiments, charging and discharging may occur with formation base 2204 attached to the battery tray, or may occur within the battery tray without formation base 2204 attached (e.g., charging and discharging modules may be in the battery tray and pre-lithiation module may be in the formation base).

[0166] 30 is a block diagram of an exemplary cell formation system 3000 for a lithium-containing secondary battery, such as secondary battery 100. The cell formation system includes a population of formation clusters 3002 and a central controller 3004. Each formation cluster 3002 is connected to a secondary battery 100 and performs a formation process on the connected secondary battery 100.

[0167] The forming clusters 3002 are communicatively coupled to the central controller 3004 by a network 3006. The network 3006 may be any type of wired or wireless network suitable for communication between the forming clusters 3002 and the central controller 3004. For example, the network 3006 may be an Inter-Integrated Circuit (I2C) network, a Controller Area Network (CAN), a Local Area Network (LAN), a Wide Area Network (WAN), etc. Although shown connected to the same network 3006 in FIG. 30, the forming clusters 3002 and the central controller 3004 may be connected to different networks or a combination of the same and different networks. For example, some of the forming clusters 3002 may be connected to a first LAN and some of the forming clusters may be connected to a second LAN, and the first and second LANs may be connected to the central controller 3004 through a WAN that is connected to both the first and second LANs.

[0168] Each forming cluster 3002 is connected to a power source 3008, such as a power grid, a generator, a solar power system, a battery, etc. The forming clusters 3002 use power from the power source 3008 to power the forming clusters and perform the forming process. Although illustrated in FIG. 30 as being connected to the same power source 3008, the forming clusters 3002 in the cell forming system 3000 may be connected to different power sources.

[0169] The group of forming clusters 3002 are supported by a housing 3010. The housing 3010 can be an enclosure such as a cabinet, or an open support such as a rack. For simplicity, two forming clusters 3002 are shown in one housing 3010 and a single forming cluster 3002 is shown in another housing, but in practice, each housing 3010 will typically support a larger number of forming clusters, such as 10, 25, 50, 100, 250, or 1000 forming clusters. Notably, the central controller 3004 is separate from (and may be located remotely from) the housings 3010 and their forming clusters 3002. Furthermore, the housings 3010 may be located in different locations from each other, so long as they are located anywhere with access to a power source 3008 and a network 3006. Furthermore, each housing 3010 can support a different number of forming clusters 3002.

[0170] 31 is a block diagram of an example formation cluster 3002. The formation cluster 3002 includes a battery connector 3100, a charging module 3102, a pre-lithiation module 3104 (sometimes referred to as a buffer module), a discharging module 3106, a communication interface 3108, a formation cluster controller 3110, a power connection 3112, a power supply unit (PSU) 3113, and a sensor 3114.

[0171] The battery connector 3100 connects the formed cluster 3002 to the secondary battery 100. The battery connector 3100 may be any connector suitable for connecting to the secondary battery 100, including a connector configured to mate with a similar connector on the battery, a clamp connector (such as an alligator clip), wires soldered or welded to the battery and the formed cluster 3002, and the like. The battery connector 3100 is configured to connect to the positive and negative poles of the secondary battery 100. In some embodiments, the battery connector 3100 also electrically connects the formed cluster 3002 to the auxiliary electrode 502. In other embodiments, the formed cluster 3002 includes a separate connector, referred to as a pre-lithiated connector, that electrically connects the formed cluster 3002 to the auxiliary electrode 502. In some embodiments, the formed cluster 3002 includes more than one battery connector 3100, with each battery connector connected to a separate one of the modules of the formed cluster (e.g., the charging module 3102, the pre-lithiated module 3104, and the discharging module 3106).

[0172] The charging module 3102 is connected to the battery connector 3100 and configured to charge the secondary battery 100 connected to the battery connector 3100. The pre-lithiation module 3104 is connected to the battery connector 3100 and configured to diffuse lithium carrier ions to the electrode active material layers (e.g., the cathode active material layer 106 and / or the anode active material layer 104) of the secondary battery 100. The discharging module 3106 is connected to the battery connector 3100 and configured to discharge the secondary battery 100.

[0173] The communication interface 3108 connects the forming clusters 3002 to the central controller 3004. The communication interface 3108 may be any wired or wireless communication interface that allows the controllers 3110 to communicate with the central controller 3004 directly or over a network. The wireless communication interface 3108 may include a radio frequency (RF) transceiver, a Bluetooth adapter, a Wi-Fi transceiver, a ZigBee transceiver, an infrared (IR) transceiver, and / or any other device and communication protocol connection for wireless communication. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group, Kirkland, Washington, and ZigBee is a registered trademark of the ZigBee Alliance, San Ramon, California.) The wired communication interface 3108 may use any suitable wired communication protocol for direct communication, including but not limited to USB, RS232, I2C, SPI, analog, and proprietary I / O protocols. In some embodiments, the wired communication interface 3108 includes a wired network adapter that enables the controller 3110 to be coupled to a network, such as the Internet, a local area network (LAN), a wide area network (WAN), a mesh network, and / or any other network for communicating with remote devices and systems via the network.

[0174] The formation cluster controller 3110 controls the operation of the formation cluster 3002 to operate as described herein. The formation cluster controller 3110 includes a processor 3116 and a memory 3118. The processor 3116 is any programmable system including a microcontroller, a microcomputer, a microprocessor, a reduced instruction set circuit (RISC), an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and any other circuit or processor capable of performing the functions described herein. The memory 3118 stores computer readable instructions executable by the processor 3116 for the control of the formation cluster 3002 as described herein. The memory 3118 can be any suitable type of memory including, but not limited to, a random access memory (RAM), such as a dynamic RAM (DRAM) or a static RAM (SRAM), a read only memory (ROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), and a non-volatile RAM (NVRAM). In some embodiments, the processor 3116 and the memory 3118 are both embodied within a microcontroller, while in other embodiments, the processor 3116 and the memory 3118 are separate components.

[0175] In an exemplary embodiment, the formation cluster controller 3110 is programmed (by instructions stored in memory 3118) to directly control each of the modules 3102, 3104, and 3106. That is, the formation cluster controller 3110 is programmed to control the pre-lithiation module 3104 to pre-lithiate (also referred to as buffering) the secondary battery 100 by controlling a charging module to charge the secondary battery 100, and to control a discharging module 3106 to discharge the secondary battery 100. The formation cluster controller 3110 is also programmed to control the entire formation process, including which of the modules 3102, 3104, and 3106 to use.

[0176] In other embodiments, one or more of the modules 3102, 3104, and 3106 include their own module controllers (with processors and memory). In such embodiments, the formation cluster controller 3110 controls the entire formation process, but the module controllers control the specific tasks of those modules. For example, the formation cluster controller 3110 may instruct the charging module 3102 to charge the secondary battery 100, and then the module controller in the charging module will control the charging module to charge the secondary battery 100 according to instructions stored in the memory of the module controller of the charging module.

[0177] In further embodiments, the forming cluster 3002 does not include a forming cluster controller 3110. Rather, each of the modules 3102, 3104, and 3106 includes its own module controller. In such embodiments, the central controller 3004 controls the entire forming process and sends instructions to the module controllers through the communication interface 3108. In such embodiments, the multiple module controllers in the forming cluster 3002 can be considered a distributed forming cluster controller 3110.

[0178] Various levels of interaction and control may be performed by the central controller 3004 and the forming cluster controller 3110 in different embodiments. For example, in some embodiments, the central controller 3004 simply sends instructions to the forming cluster 3002 to initiate the forming process. Then, in response to the instructions, the forming cluster controller 3110 controls the modules 3102, 3104, and 3106 to perform the forming process. Alternatively, in response to the instructions, the forming cluster controller 3110 may instruct the modules 3102, 3104, and 3106 to perform their respective functions at the appropriate times. In other embodiments, the central controller 3004 sends instructions to the forming cluster 3002 to perform individual parts of the forming process (e.g., "charge the battery here"), and the forming cluster controller 3110 or the module controllers perform the tasks instructed by the central controller. In some embodiments, the central controller 3004 may send instructions to the forming cluster 3002 on how to perform one or more of the forming tasks, including sending a control algorithm. In some embodiments, the forming cluster controller 3110 or module controller may store instructions for multiple methods of performing the same task (e.g., fast charging, slow charging, charging with rest periods, etc.), and the central controller's instructions may instruct the forming cluster 3002 which method to use.

[0179] In some embodiments, the central controller 3004 can program or update the programming of the formation cluster controllers 3110 or the module controllers. For example, the central controller 3004 can send a control algorithm to the formation cluster 3002, and the formation cluster controller 3110 and / or the module controllers can store the control algorithm in their respective memories. In other embodiments, the central controller can send modifications to a control algorithm already stored in the formation cluster, such as changing variables, changing timing, etc. The formation cluster controller 3110 or the controller module then stores the modifications in memory for use in the formation process.

[0180] The formation cluster controller 3110, in some embodiments, also transmits information back to the central controller 3004. The information sent to the central controller 3004 may include confirmation that the command was received, confirmation that the commanded process has begun, the status of the operation being performed, data collected from the sensors 3114, or any other suitable information.

[0181] The power connection 3112 connects the forming cluster 3002 to the power source 3008. The power connection 3112 can be any connector suitable for connection to the power source 3008, including a plug configured to insert into a mating socket of the power source, wires soldered or welded to the power source, a clamp connector for clamping to the terminals or wires of the power source, etc. The PSU 3113 converts and / or distributes power from the power source to the remainder of the forming cluster 3002 for use in the forming process. The PSU 3113 may be an AC / DC power converter, a DC / DC power converter, an inverter, or any other unit suitable for converting power and / or distributing power to the forming cluster. Some embodiments do not include a PSU and utilize power directly from the power source 3008.

[0182] The sensor 3114 is any sensor capable of monitoring a variable important to the formation process. For example, the sensor 3114 may be a voltage sensor for monitoring the voltage of the secondary battery 100, an ambient temperature sensor for monitoring the temperature surrounding the formation cluster 3002, a temperature sensor for monitoring the temperature of the battery assembly or components of the formation cluster, a current sensor for monitoring the current flowing into, out of, or through the battery assembly, etc. Some embodiments include more than one sensor 3114, including a combination of the aforementioned sensors. Furthermore, some sensors 3114 may perform more than one of the above-mentioned monitoring tasks.

[0183] The modular and distributed nature of the cell formation system 3000 allows the system to be easily expanded or contracted as desired. Unlike conventional centralized systems that are configured to form a set number of batteries at a time, the system 3000 can be expanded to any number of batteries by simply adding more forming clusters 3002 (including increasing the number of batteries by as little as one additional battery). In conventional centralized systems, increasing the number of batteries formed requires the acquisition of additional systems and an increase in a set number of batteries (determined by the size and configuration of the centralized system obtained). Furthermore, centralized systems typically require running significant additional wiring to each additional battery to provide controlled power and communication to the additional batteries. In contrast, the cell formation system 3000 only requires connecting the additional forming clusters 3002 to a power source and an existing communication network. The forming clusters 3002 in the system 3000 do not all need to be the same, as long as the central controller 3004 is aware of the configuration of each forming cluster 3002. Furthermore, the forming clusters 3002 in the system 3000 can be used to form different batteries at different times or simultaneously, so long as the central controller 3004 or forming cluster controller 3110 is aware of which secondary batteries 100 are connected to the forming clusters 3002.

[0184] 32 is a block diagram of an exemplary pre-lithiation module 3104 for use in the cell formation cluster 3002. As described above, the pre-lithiation module 3104 is configured to diffuse lithium into the electrode active material layers (e.g., the cathode active material layer 106 and / or the anode active material layer 104) of the secondary battery 100. The pre-lithiation module 3104 includes a switched capacitor circuit 3200, a pre-lithiation module controller 3202, a battery connector 3204, a pre-lithiation connector 3206, and a communication interface 3208.

[0185] The switched capacitor circuit 3200 is a switched resistor-capacitor network. The switched capacitor circuit 3200 is described in more detail below with reference to FIG. 33. Generally, in a first stage, a current can be passed through the circuit 3200 to charge the capacitor network, and then in a second stage, the energy stored in the capacitor network is discharged through a discharge resistor and released as heat. In the pre-lithiation module 3104, a current can be passed between the auxiliary electrode 502 and one of the electrodes of the secondary battery 100 to diffuse lithium from the auxiliary electrode 502 to the electrode active material layer of the secondary battery 100.

[0186] The pre-lithiation module controller 3202 controls the operation of the pre-lithiation module 3104 to pre-lithiate the secondary battery 100 by selectively passing a current through the auxiliary electrode 502 to diffuse lithium into the electrode active material layer of the secondary battery 100. The pre-lithiation module controller 3202 includes a processor 3210 and a memory 3212. The memory 3212 stores instructions that, when executed by the processor 3210, cause the processor to perform pre-lithiation as described herein. The processor 3210 is any programmable system, including a microcontroller, a microcomputer, a microprocessor, a reduced instruction set circuit (RISC), an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and any other circuit or processor capable of performing the functions described herein. The memory 3212 may be any suitable type of memory, including, but not limited to, random access memory (RAM), such as dynamic RAM (DRAM) or static RAM (SRAM), read only memory (ROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), and non-volatile RAM (NVRAM). In some embodiments, the processor 3210 and memory 3212 are both embodied within a microcontroller, while in other embodiments, the processor and memory are separate components.

[0187] The battery connector 3204 connects the pre-lithiation module 3104 to the secondary battery 100. The battery connector 3204 may be the battery connector 3100 or may be a separate battery connector connected only to the pre-lithiation module 3104. The battery connector 3204 may be any connector suitable for connection to the secondary battery 100, including a connector configured to mate with a similar connector on the battery, a clamp connector (such as an alligator clip), wires soldered or welded to the battery and the pre-lithiation module 3104, etc. The battery connector 3204 is configured to connect to the positive and negative poles of the secondary battery 100.

[0188] The pre-lithiated connector 3206 connects the pre-lithiated module 3104 to the auxiliary electrode 502 of the secondary battery 100. The pre-lithiated connector 3204 may be any connector suitable for connection to the secondary battery 100, including a connector configured to mate with a similar connector on the battery, a clamp connector (such as an alligator clip), wires soldered or welded to the battery and pre-lithiated module 3104, etc. In some embodiments, the pre-lithiated connector 3206 is part of the battery connector 3100.

[0189] The communication interface 3208 connects the pre-lithiation module 3104 to the central controller 3004. The communication interface 3208 may be the communication interface 3108 or may be a separate communication interface. The communication interface 3208 may allow the pre-lithiation module 3104 to communicate directly with the central controller 3004 or may allow the pre-lithiation module 3104 to communicate indirectly with the central controller, for example, via the formation cluster controller 3110. The communication interface 3208 may be any wired or wireless communication interface that allows the controller 3202 to communicate with the central controller 3004 directly or over a network. The wireless communication interface 3208 may include a radio frequency (RF) transceiver, a Bluetooth adapter, a Wi-Fi transceiver, a ZigBee transceiver, an infrared (IR) transceiver, and / or any other device and communication protocol connection for wireless communication. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group, Kirkland, Washington, and ZigBee is a registered trademark of the ZigBee Alliance, San Ramon, California.) The wired communication interface 3208 can use any suitable wired communication protocol for direct communication, including, but not limited to, USB, RS232, I2C, SPI, analog, and proprietary I / O protocols. In some embodiments, the wired communication interface 3108 includes a wired network adapter that allows the controller 3202 to be coupled to a network, such as the Internet, a local area network (LAN), a wide area network (WAN), a mesh network, and / or any other network for communicating with remote devices and systems over the network.

[0190] 33 is a simplified circuit diagram of an exemplary embodiment of a switched capacitor circuit 3200 connected to a secondary battery 100. The switched capacitor circuit 3200 includes a microcontroller 3300, a storage capacitor 3302, a discharge resistor 3304, a first switch 3306, and a second switch 3308.

[0191] Microcontroller 3300 controls switched capacitor circuit 3200 according to a control algorithm stored in its memory. In an exemplary embodiment, microcontroller 3300 is also pre-lithiation module controller 3202. In other embodiments, pre-lithiation module controller 3202 is separate from microcontroller 3300. In an exemplary embodiment, the microcontroller is a PIC 16F15323 microcontroller from Microchip Technology Inc. of Chandler, Arizona, USA. In other embodiments, any other suitable microcontroller may be used. In this embodiment, microcontroller 3300 is powered by power supply 3008 via PSU 3113.

[0192] The microcontroller 3300 controls the pre-lithiation of the secondary battery 100 by selectively conducting current through the auxiliary electrode 502 by controlling the first switch 3306 and the second switch 3308. The first switch 3306 is an N-channel enhancement mode metal oxide semiconductor field effect transistor (MOSFET) and the second switch 3308 is a P-channel enhancement mode MOSFET. Other embodiments may use any other suitable switches. By closing the first switch 3306 and opening the second switch 3308, the microcontroller 3300 forms a first current path from the negative bus bar 112 of the secondary battery 100 through the first switch 3306 to the auxiliary electrode. The first current path includes a storage capacitor 3302. When a current flows through the first current path, lithium diffuses from the auxiliary electrode 502 to the electrode active material layer of the secondary battery 100 and energy is stored in the storage capacitor 3302. The microcontroller 3300 then closes the second switch 3308 and opens the first switch 3306 to establish a second current path. The second current path includes a storage capacitor 3302, a discharge resistor 3304, and a second switch 3308. As current flows through the second current path, the energy stored in the capacitor 3302 is discharged through the discharge resistor 3304 and released as heat.

[0193] In an exemplary embodiment, lithium migrates from the auxiliary electrode 502 to the electrode active material layer of the positive electrode of the secondary battery 100. In other embodiments, the diffusion is to the electrode active material layer of the negative electrode of the secondary battery 100 by connecting the switched capacitor circuit 3200 such that the first current loop includes the anode bus bar 110 instead of the cathode bus bar 112. In yet other embodiments, the switched capacitor circuit 3200 may be duplicated such that there are two first current loops, one including the anode bus bar 110 and the other including the cathode bus bar 112. Such an embodiment allows a single pre-lithiation module 3104 to migrate lithium from the auxiliary electrode 502 to the active material layers of the positive and negative electrodes of the secondary battery 100 without having to stop the formation process to reconfigure the connections to the secondary battery 100 and the auxiliary electrode 502, and without having to use two separate pre-lithiation modules 3104.

[0194] Pre-lithiation of the secondary battery 100 using the switched capacitor circuit 3200 generally draws charge from one small packet of the secondary battery 100 at a high rate at a time. Thus, the average current is equal to the packet charge / discharge frequency multiplied by the packet size in coulombs, as shown by:

[0195]

number

[0196]

number

[0197] To control the switched capacitor circuit 3200, the microcontroller 3300 uses a pulse frequency modulated (PFM) control signal to the first switch 3306 and the second switch 3308. PFM is described by pulses with a fixed width (i.e., each pulse is for a fixed length of time) with a variable time between the pulses. The time between the pulses is varied to provide different frequencies for charge transfer. The faster the packets move (i.e., the higher the frequency of the fixed width pulses), the higher the current conducted through the auxiliary electrode 502. Conversely, the lower the frequency of the pulses (i.e., the longer the time between the pulses), the lower the current conducted through the auxiliary electrode 502. The upper limit of the current conducted through the auxiliary electrode 502 is determined by the settling time of the RC circuit element of the switched capacitor circuit 3200. Thus, by varying the frequency of the control pulses to the switches 3306 and 3308, the microcontroller 3300 can control the current flowing through the auxiliary electrode 502. In another embodiment, the microcontroller 3300 uses pulse width modulated (PWM) control signals to the first switch 3306 and the second switch 3308. With PWM control, pulses occur at a fixed frequency, but the length of each pulse can be varied to control the amount of charge moved, thereby controlling the amount of current.

[0198] FIG. 34A is a graph of a series of PFM control pulses applied to switches 3306 and 3308 as a function of time. As shown, in a first portion 3400 of the series of pulses, fixed width pulses are applied at a higher frequency than in a second portion 3402 of the series of pulses. FIG. 34B is a graph of the resulting current through the auxiliary electrode 502 in response to the control pulses shown in FIG. 34A as a function of time. The current increases in a sawtooth pattern during the first portion 3400 to a first maximum current 3404. When the frequency of the pulses is reduced in the second portion 3402, the current through the auxiliary electrode 502 decreases to a second maximum current 3406 that is lower than the first maximum current 3404.

[0199] 35 is a circuit diagram of an exemplary implementation of a switched-capacitor circuit 3200 connected to a secondary battery 100. Like components share reference numbers with their corresponding components in FIG. 33. In this embodiment, the microcontroller 3300 is powered by the secondary battery 100 rather than the PSU 3113. The microcontroller 3300 presents a small leakage on the secondary battery 100, generally in the range of 50 nA to 100 nA, in most situations except when it is in an active state.

[0200] During the pre-lithiation process, the microcontroller 3300 detects the voltage at the negative electrode of the secondary battery 100 and the voltage V at the auxiliary electrode 502. L Monitor the cathode voltage V c To measure V, pin RC3 of the microcontroller 3300 is driven low with respect to the positive terminal of the secondary battery 100, which is considered the reference point for this circuit. This creates a voltage divider, y is read out on pin RA0 of the microcontroller 3300. Then, the cathode voltage V c is calculated by the microcontroller 3300 as follows:

[0201]

number

[0202]

number

[0203]

number

[0204]

number

[0205] When measuring the voltage, the microcontroller 3300 may use filtering to increase the stability of the measurement. For example, the microcontroller 3300 may use decimation, non-linear IIR filtering, or some combination of such signal processing to improve measurement stability. Filtering can improve resolution and reduce noise before the data is consumed by the management functions of the microcontroller 3300. This provides a relatively clean decision-making regardless of any external factory noise that may otherwise affect the measurement. Because pre-lithiation is a relatively slow process (often requiring tens of hours), significant signal processing can be used without much concern regarding time.

[0206] 36A-36C are graphs of exemplary pre-lithiation profiles used by the microcontroller 3300 to perform pre-lithiation of the secondary battery 100. FIG. 36A is a graph showing the buffer current (i.e., the current through the auxiliary electrode 502) as a function of the voltage difference in millivolts (mV) between the negative electrode of the secondary battery 100 and the auxiliary electrode 502. FIG. 36B is a graph showing the period of pulses as a function of the voltage difference in mV between the negative electrode of the secondary battery 100 and the auxiliary electrode 502. FIG. 36C is a graph showing the number of pulses as a function of the voltage difference in mV between the negative electrode of the secondary battery 100 and the auxiliary electrode 502. Of course, different profiles may be used for secondary batteries 100 having different capacities and / or different upper charging voltage limits.

[0207] The pre-lithiation profiles shown in Figures 36A-36C were used in conjunction with the embodiment of the switched capacitor circuit 3200 shown in Figure 33 to pre-lithiate a secondary battery 100. The results of this process are shown in Figures 37A and 37B. Figure 37A is a graph of the cathode-to-anode voltage 3700 and the cathode-to-auxiliary electrode voltage 3702 as a function of time. Figure 37B is a graph of the buffer current as a function of time.

[0208] The embodiments of the present disclosure utilize an auxiliary electrode to transfer or buffer carrier ions to the secondary battery during or after the initial formation of the secondary battery. Transferring carrier ions to the secondary battery (also referred to as pre-lithiation or buffering) provides the technical advantage of mitigating carrier ion loss during formation, for example, by the SEI, thereby improving the capacity of the secondary battery. Furthermore, transferring or buffering carrier ions to the secondary battery provides the negative electrode of the secondary battery with additional carrier ions in excess of the positive electrode coulombic capacity of the secondary battery, thereby providing a reservoir of additional carrier ions over the cycle life of the secondary battery, further mitigating carrier ion loss during cycling due to side reactions that remove carrier ions from availability during cycling. The result of the additional carrier ions in the negative electrode provides the further technical advantage of reducing the amount of capacity loss in the secondary battery from one discharge-charge cycle to the next, thereby improving the overall capacity of the secondary battery during cycle life.

[0209] In some examples, during formation and / or prelithiation processes of a secondary battery as described herein, gas or other vapors may be generated and / or otherwise formed within an enclosure (e.g., enclosure 504 (FIG. 6) and / or first enclosure layer 510 and second enclosure layer 511 (FIG. 6)) of the secondary battery. For example, gas bubbles may form between an auxiliary electrode (e.g., auxiliary electrode 502 (FIG. 6)) and another portion (e.g., unit cell 200 (FIG. 2)) of the secondary battery. The presence of gas can prevent or inhibit uniform anode prelithiation in the secondary battery.

[0210] Thus, the cell formation system of the present disclosure may include a compression fixture that applies a compressive force to the secondary battery during the formation and / or pre-lithiation process of the secondary battery, as further described herein. The compression force may help prevent gas formation or transport between the auxiliary electrode and other portions of the secondary battery. The compression force may also promote uniform distribution of lithium (e.g., during the formation and / or pre-lithiation process). The compression force may also help form better mechanical and / or electrical connections of the secondary battery, as it holds the secondary battery securely in place within the battery tray.

[0211] FIG. 38 is a perspective view of a portion of an exemplary cell formation system 3800 according to one suitable embodiment of the present disclosure. The cell formation system 3800 includes various components and mechanisms for applying a compressive force to one or more secondary batteries during the formation and / or pre-lithiation process. The illustrated cell formation system 3800 includes a battery tray 3810, a compression fixture 3830 coupled to the battery tray 3810, and a loading mechanism 3860 operable to load and unload secondary batteries into the compression fixture 3830 and the battery tray 3810. In other embodiments, the cell formation system 3800 may include additional or fewer elements than those shown in FIG. 38. For example, the cell formation system 3800 may include elements of the cell formation systems 2200 and 3000 described above with reference to FIGS. 22 and 30, respectively. In some embodiments, for example, the cell formation system 3800 includes a forming base 2204 , a loading station 2206 , a charging station 2208 , a forming station 2210 , one or more forming clusters 3002 , a central controller 3004 , and / or a power source 3008 .

[0212] The battery tray 3810 may have the same or substantially the same structure as the battery tray 2202 illustrated and described with respect to FIGS. 22-29. For example, the battery tray 3810 may include a plurality of battery slots 3820, each configured (e.g., sized, shaped, and positioned) to receive and hold a secondary battery (e.g., secondary battery 100) or a portion of a secondary battery therein. The battery slots 3820 may have the same or substantially the same structure as the battery slots 2212 illustrated and described with respect to FIGS. 22-29. The illustrated battery tray 3810 includes 120 battery slots 3820 arranged in three rows of 40 slots each. Other embodiments may include more or fewer battery slots 3820 arranged in more or fewer rows.

[0213] In an exemplary embodiment, each row of battery slots 3820 is configured to receive one of the compression fixtures 3830. In other words, the illustrated battery tray 3810 is configured to receive three compression fixtures 3830, one for each row of battery slots 3820 defined by the battery tray 3810. In other embodiments, a single compression fixture 3830 may extend across or span multiple rows of battery slots 3820. In some embodiments, for example, a single compression fixture can span all three rows of battery slots in the battery tray 3810.

[0214] 39, in this embodiment, the battery tray 3810 also includes one or more alignment features 3910 configured to cooperatively engage with corresponding alignment features of the compression fixture 3830 (e.g., alignment feature 4114 shown in FIG. 42) to facilitate alignment and coupling of the compression fixture 3830 to the battery tray 3810. In the exemplary embodiment, the alignment features 3910 are shown as raised posts or pins, but the battery tray 3810 may include any other suitable alignment features that enable the compression fixture 3830 to function as described herein. The exemplary battery tray 3810 includes 24 alignment features arranged in three sets of eight alignment features, where each set of alignment features corresponds to one of the rows of battery slots. Other embodiments may have any other suitable number of alignment features in any suitable arrangement.

[0215] 40, the compression fixture 3830 includes a base 4010 and a plurality of compression plates 4020 coupled to the base 4010. As described in more detail herein, the plurality of compression plates 4020 includes a plurality of stationary compression plates 4030 and a plurality of movable compression plates 4040 arranged in an alternating configuration (i.e., the compression plates 4020 are arranged alternating between the stationary compression plates 4030 and the movable compression plates 4040). The compression plates 4020 are operable to apply a compressive force to a secondary battery (e.g., the secondary battery 100) loaded in the compression fixture 3830 during a cell formation and / or pre-lithiation process, as described further herein.

[0216] FIG. 41 is a top perspective view of the compression fixture base 4010 and FIG. 42 is a bottom perspective view of the compression fixture base 4010. The base 4010 is sized and shaped to be received within and coupled to the battery tray 3810. As shown in FIG. 41 , the base 4010 extends a length 4102 in a longitudinal direction x, a width 4104 in a lateral direction y, and a height 4106 in a vertical direction z. The base 4010 may have any suitable length 4102, width 4104, and height 4106 that enables the compression fixture 3830 to function as described herein. The height 4106 extends between a first or top planar surface 4108 and an opposing second or bottom planar surface 4110.

[0217] The base 4010 may be permanently (i.e., non-removably) or removably coupled to the battery tray 3810. In an exemplary embodiment, the base 4010 is removably coupled to the battery tray 3810 via fasteners (e.g., screws, bolts, pins, etc., not shown) inserted through fastener openings 4112 defined in the base 4010. Other embodiments of the base 4010 may be removably coupled to the battery tray 3810 using any suitable coupling means that enables the compression fixture 3830 to function as described herein.

[0218] The base 4010 also includes a number of complementary alignment features 4114 configured to cooperatively engage with corresponding alignment features of the battery tray 3810 (e.g., alignment feature 3910 shown in FIG. 39 ) to facilitate alignment and coupling of the compression fixture 3830 to the battery tray 3810. Although the alignment features 4114 are shown as counterbore in the exemplary embodiment, the base 4010 may include any other suitable alignment features that enable the compression fixture 3830 to function as described herein. The exemplary base 4010 includes eight alignment features 4114, or as many alignment features 4114 as there are alignment features 3910 in one set of alignment features of the battery tray 3810.

[0219] The base 4010 also includes a compression plate retaining section 4116 configured to receive and retain a compression plate 4020. In the illustrated embodiment, the compression plate retaining section 4116 includes a pair of rails 4118 extending vertically from the top surface 4108. In the illustrated embodiment, each rail 4118 extends longitudinally across the entire length 4102 of the base 4010, although in other embodiments the rails 4118 can extend longitudinally less than the entire length 4102 of the base 4010. The rails 4118 are laterally spaced apart from one another and define longitudinally extending recesses or channels 4120 therebetween.

[0220] 43, each rail 4118 extends perpendicularly from the top surface 4108 of the base 4010 and includes a lateral inner surface 4302, a lateral outer surface 4304, and a top surface 4306 extending between the lateral inner surface 4302 and the lateral outer surface 4304. The top surface 4306 of each rail 4118 is substantially flat and smooth to facilitate movement (e.g., sliding) of the movable compression plate 4040 along the top surface 4306 of the rail 4118. The channel 4120 is defined by the lateral inner surface 4302 of each rail 4118 and a concave surface 4308 extending between the rails 4118. The concave surface 4308 is located opposite the bottom surface 4110 of the base 4010. In the exemplary embodiment, the concave surface 4308 is spaced from the bottom surface 4110 a distance less than the height 4106 of the base 4010. In other words, the height or thickness of the base 4010 within the compression plate retaining section 4116 is less than the height 4106 of the base 4010 measured between the top surface 4108 and the bottom surface 4110 .

[0221] Each rail 4118 defines a number of compression plate channels 4310, each configured (e.g., sized, shaped, and positioned) to receive a portion of one of the fixed compression plates 4030 therein. In the illustrated embodiment, each compression plate channel 4310 extends laterally outward from the lateral inner surface 4302 of the rail 4118 and extends vertically through the rail 4118 from the top surface 4306 to the concave surface 4308. The compression plate channels 4310 are defined in each rail 4118 such that each of the compression plate channels 4310 defined in one of the rails 4118 is laterally aligned with a corresponding compression plate channel 4310 defined in the other of the rails 4118.

[0222] Each compression plate channel 4310 receives at least a portion of the fixed compression plate 4030 when the fixed compression plate 4030 is coupled to the base 4010. For example, to couple the fixed compression plate 4030 to the base 4010, a side edge of the fixed compression plate 4030 is inserted into an upper portion of the laterally opposed compression plate channel 4310, and the fixed compression plate 4030 moves (e.g., downward) toward the base 4010 (i.e., toward the concave surface 4308) until a lower end of the fixed compression plate 4030 is flush or substantially flush with the concave surface 4308. The configuration of the compression plate channels 4310 helps to hold the fixed compression plate 4030 in a fixed position relative to the moveable compression plate 4040.

[0223] The base 4010 also has a plurality of battery openings 4312 defined therein. The battery openings 4312 of the compression fixture 3830 are positioned or otherwise arranged within the base 4010 to align with the battery slots 3820 ( FIG. 38 ) of the battery tray 3810 when the base 4010 is coupled to the battery tray 3810. Thus, an electrical terminal of a secondary battery disposed within the compression fixture 3830 can extend through one of the battery openings 4312 of the compression fixture 3830 and one of the battery slots 3820 of the battery tray 3810. In the illustrated embodiment, each battery opening 4312 is defined in the base 4010 within the compression plate retention section 4116 (specifically, between the rails 4118) and extends through the base 4010 from the concave surface 4308 to the bottom surface 4110. Each battery opening 4312 is elongated in the lateral direction y and has a width (measured in the lateral direction y in the orientation shown in FIG. 43) sufficient to receive one or more terminals or conductive tabs therein (e.g., first terminal 124, second terminal 125, and / or conductive tab 508-1).

[0224] In the illustrated embodiment, the base 4010 also includes a number of stops 4314 shown in the form of a raised lip or rim that extends laterally across the channel 4120 from one rail 4118 to the other rail 4118. Each stopper 4314 extends vertically upwardly from the concave surface 4308 and is spaced from an adjacent stopper 4314 a sufficient distance to receive one of the fixed compression plates 4030 and one of the movable compression plates 4040 therebetween. As described further herein, each stopper 4314 is configured (e.g., sized, shaped, and positioned) to inhibit or prevent longitudinal movement of the movable compression plate 4040 beyond a particular position (e.g., the second position of the movable compression plate 4040). The plurality of stops 4314 segment or divide the compression plate retaining section 4116 into a plurality of pockets 4316, each pocket sized and shaped to receive one of the fixed compression plates 4030 and one of the movable compression plates 4040. Each pocket 4316 also includes a pair of laterally opposed compression plate channels 4310 defined by rails 4118 and one of the battery openings 4312. In one exemplary embodiment, the base 4010 includes 40 pockets 4316 arranged in a row. Other embodiments include more or fewer pockets 4316 arranged in one or more rows.

[0225] Referring again to FIG. 40 , the compression plates 4020 are arranged in an alternating pattern alternating between the fixed compression plates 4030 and the movable compression plates 4040. The illustrated compression fixture 3830 includes 40 fixed compression plates 4030 and 40 movable compression plates 4040. Other embodiments may include more or fewer fixed compression plates 4030 and / or movable compression plates 4040. Each of the compression plates 4020 may be made of any suitable material that helps provide a compressive force to the secondary battery when the secondary battery is disposed between one of the movable compression plates 4040 and a corresponding one of the fixed compression plates 4030. For example, each fixed compression plate 4030 and each movable compression plate 4040 may be made of plastic, aluminum, or a combination thereof. In other embodiments, the fixed compression plates 4030 and / or the movable compression plates 4040 may be made of other materials. In some embodiments, the surface (eg, the flat surface) of each compression plate may be anodized or coated with a non-conductive material.

[0226] The compression plates 4020 are coupled to the compression fixture base 4010 and are arranged in compression plate sets 4050, with each compression plate set including one of the fixed compression plates 4030 and a corresponding one of the movable compression plates 4040. With further reference to FIGS. 44-46 , each fixed compression plate 4030 of the set 4050 is spaced apart from a corresponding movable compression plate 4040 of the set 4050, thereby defining a battery receptacle 4402 therebetween. Each movable compression plate 4040 is movable relative to the corresponding fixed compression plate 4030 such that a width 4404 of the battery receptacle 4402 is increased (e.g., to insert a secondary battery into the battery receptacle 4402) or decreased (e.g., to apply a compressive force to a secondary battery disposed in the battery receptacle 4402). More specifically, each movable compression plate 4040 is movable (e.g., moved linearly by a sliding motion) toward and away from the fixed compression plate 4030 between a first position (shown in FIG. 45) and a second position (shown in FIGS. 44 and 46). The movable compression plate 4040 is disposed closer to the fixed compression plate 4030 in the first position than in the second position. When the movable compression plate 4040 is in the second position, a secondary battery may be loaded or removed from the battery receptacle 4402 (e.g., using the loading mechanism 3860).

[0227] The exemplary compression fixture 3830 also includes one or more alignment rods 4406 to facilitate maintaining the orientation (e.g., parallel orientation with respect to one another) of the fixed compression plates 4030 and the movable compression plates 4040. Each alignment rod 4406 extends at least partially along the length of the compression fixture 3830 (i.e., in the longitudinal direction x) and is oriented parallel to each of the other alignment rods 4406. Each fixed compression plate 4030 and each movable compression plate 4040 is coupled to an alignment rod 4406 to facilitate maintaining the orientation and alignment of each fixed compression plate 4030 and each movable compression plate 4040. For example, each fixed compression plate 4030 and each movable compression plate 4040 may include a through hole (described in more detail herein) through which the alignment rod 4406 extends. In this manner, the fixed compression plate 4030 and the movable compression plate 4040 are prevented or inhibited from rotating (e.g., about the x-axis, y-axis, or z-axis) and are held in a parallel orientation to one another. The movable compression plate 4040 is operable to move or slide (e.g., in the longitudinal direction x) along the alignment rod 4406 to move between a first position and a second position. The alignment rod 4406 may be constructed of and / or coated with a low friction material that helps enable sliding or other movement of the movable compression plate 4040 along the alignment rod 4406. Suitable low friction materials include, but are not limited to, for example, plastic, thermoplastic, polyester, nylon, acetal, polytetrafluoroethylene (PTFE), polyimide, polyetheretherketone (PEEK), and polyphenylene sulfide (PPS).

[0228] The compression fixture 3830 may include any suitable number of alignment rods 4406 that enable the compression fixture 3830 to function as described herein. The compression fixture 3830 in the illustrated embodiment includes four alignment rods 4406 (three shown in FIG. 44 ) disposed adjacent respective corners of the fixed compression plate 4030 and the movable compression plate 4040. For example, in the illustrated embodiment, a first alignment rod 4406 extends through a first through hole located at or near the upper right corner of each compression plate 4020, a second alignment rod 4406 extends through a second through hole located at or near the upper left corner of each compression plate 4020, a third alignment rod 4406 extends through a third through hole located at or near the lower right corner of each compression plate 4020, and a fourth alignment rod 4406 extends through a fourth through hole located at or near the lower left corner of each compression plate 4020. Other embodiments may include more or less than four alignment rods 4406. Additionally, other embodiments may include other alignment mechanisms in addition to, or in place of, the alignment rods 4406. For example, the compression fixture 3830 may include one or more alignment wires in place of, or in addition to, alignment rods.

[0229] 45 and 46, each compression plate set 4050 includes one or more biasing elements or springs 4408 operably coupled to the movable compression plate 4040 of the set 4050. The one or more springs 4408 bias the movable compression plate 4040 toward the fixed compression plate 4030 of the set 4050 (i.e., toward the first position). The springs 4408 are disposed between the movable compression plate 4040 and a fixed or non-movable surface of the movable compression plate 4040 opposite the fixed compression plate 4030. In this embodiment, the one or more springs 4408 are disposed between the movable compression plate 4040 of one set 4050 of compression plates 4020 and the fixed compression plate 4030 of an adjacent set 4050 of compression plates 4020 such that the springs 4408 engage both the movable compression plate 4040 and the fixed compression plate 4030. In other embodiments, one or more springs 4408 may be disposed between the movable compression plate 4040 and any other surface.

[0230] As shown in FIG. 45 , when the movable compression plate 4040 is in the first position, the spring 4408 is in an expanded state. As the movable compression plate 4040 moves from the first position to the second position, the spring 4408 is compressed between the movable compression plate 4040 of one set 4050 and the fixed compression plate 4030 of the adjacent set 4050. The compressive force of the spring 4408 urges the movable compression plate 4040 toward the first position and toward the fixed compression plate 4030 of the set 4050. In the absence of an applied force (e.g., from the loading mechanism 3860), the spring 4408 moves the movable compression plate 4040 along the alignment rod 4406 from the second position toward the first position. The spring 4408 also exerts a compressive force on the movable compression plate 4040, which in turn exerts a compressive force on the secondary battery disposed in the battery receptacle 4402.

[0231] Each compression plate set 4050 may include any suitable number and type of springs 4408 that enable the compression fixture 3830 to function as described herein. In an exemplary embodiment, each compression plate set 4050 includes four springs 4408, each positioned adjacent a respective corner of the movable compression plate 4040. For example, a first spring 4408 is positioned at or near the top right region of the movable compression plate 4040, a second spring 4408 is positioned at or near the top left region of the movable compression plate 4040, a third spring 4408 is positioned at or near the bottom right region of the movable compression plate 4040, and a fourth spring 4408 is positioned at or near the bottom right region of the movable compression plate 4040. Arranging the springs 4408 in this manner facilitates applying pressure evenly across the surface of the secondary battery. Other embodiments may include more or fewer springs 4408. The spring 4408 in the illustrated embodiment is a helical coil spring, although other types of springs 4408 may be used.

[0232] Other embodiments may include a biasing element in addition to or instead of spring 4408. For example, some embodiments may include an active biasing element (as compared to a passive biasing element such as spring 4408) that requires some type of active control or actuation. In some embodiments, for example, compression plate set 4050 may include an inflatable balloon or airbag coupled in communication with a suitable fluid source (e.g., compressed air) that inflates and deflates to apply a compressive force to the secondary battery. Additionally, in embodiments that include an inflatable balloon or airbag, moveable compression plate 4040 may be omitted and the inflatable balloon or airbag may apply a compressive pressure directly to the secondary battery.

[0233] Each compression plate set 4050 of the exemplary embodiment also includes one or more spacers 4410 disposed between the fixed compression plate 4030 and the movable compression plate 4040 of the set 4050. The spacers 4410 limit a minimum distance or spacing between the fixed compression plate 4030 and the movable compression plate 4040. That is, the spacers 4410 are provided or otherwise used to maintain a minimum distance between the movable compression plate 4040 and the fixed compression plate 4030 and / or to maintain a minimum spacing or width 4404 of the battery receptacle 4402. The fixed minimum spacing may be equal or substantially equal to one or more dimensions of a secondary battery (e.g., a thickness of the secondary battery) to be inserted into the battery receptacle 4402. The spacer 4410 can also facilitate maintaining spacing between the fixed compression plate 4030 and the movable compression plate 4040 when no secondary battery is disposed in the battery receptacle 4402 so that an actuator or other component of the loading mechanism 3860 can interact with the movable compression plate 4040 (e.g., to load a secondary battery into the battery receptacle 4402). The spacer 4410 and the battery receptacle 4402 are disposed in a non-sprung space of the array. For example, the arrangement of the array of compression plates 4020, springs 4408, and spacers 4410 can be: spring(s) 4408, movable compression plate 4040, spacer(s) 4410, fixed compression plate 4030, spring(s) 4408, movable compression plate 4040, spacer(s) 4410, fixed compression plate 4030, etc.

[0234] Each compression plate set 4050 may include any suitable number of spacers 4410 that enable the compression fixture 3830 to function as described herein. In the exemplary embodiment, each compression plate set 4050 includes four spacers 4410, although other embodiments may include more or less than four spacers. Further, in the exemplary embodiment, each spacer 4410 is annular and is disposed concentrically with a respective through hole of the moveable compression plate 4040 such that one of the alignment rods 4406 extends through each of the spacers 4410 and each spacer 4410 is coupled to one of the alignment rods 4406. In other embodiments, the spacers 4410 may be disposed in other positions relative to the alignment rods 4406 and the through holes of the moveable compression plate 4040.

[0235] The spacers 4410 may be coupled to or integrally formed with one of the fixed compression plate 4030 or the movable compression plate 4040. For example, in the illustrated embodiment, each spacer 4410 is integrally formed with a respective movable compression plate 4040. In other embodiments, the spacers 4410 may be formed separately from and coupled to the movable compression plate 4040. In yet other embodiments, the spacers 4410 may be coupled to or integrally formed with the fixed compression plate 4030.

[0236] In operation, the springs 4408, in combination with the moveable compression plate 4040, the fixed compression plate 4030, and the spacers 4410, are used to apply a compressive force to a secondary battery disposed in the battery receptacle 4402. As shown in FIGS. 47-54, to load, for example, a secondary battery 5100 (FIG. 51) into the battery receptacle 4402, the moveable compression plate 4040 is moved (e.g., using the loading mechanism 3860) from a first position (shown in FIGS. 47 and 48) to a second position (shown in FIGS. 49-52) to compress the springs 4408 between the moveable compression plate 4040 of one set 4050 and the fixed compression plate 4030 of an adjacent set 4050. As shown in FIGS. 51 and 52, when the secondary battery 5100 is placed in the battery receptacle 4402, the movable compression plate 4040 can be moved from the second position toward the first position (e.g., by releasing the movable compression plate 4040 from the loading mechanism 3860) to engage with the secondary battery 5100 placed in the battery receptacle 4402, as shown in FIGS. 53 and 54. Depending on the thickness of the secondary battery 5100 placed in the battery receptacle 4402, the movable compression plate 4040 can engage with the secondary battery 5100 before returning to the first position. That is, when the secondary battery 5100 is placed in the battery receptacle 4402, the movable compression plate 4040 may not return completely to the first position due to the thickness of the secondary battery 5100. The spring 4408 exerts a compressive force on the secondary battery 5100 in the battery receptacle 4402 via the movable compression plate 4040. The secondary battery 5100 loaded into the compression fixture 3830 may be the same or substantially the same as the secondary batteries described herein, such as the secondary battery 100. Additionally, the secondary battery 5100 may be loaded into the compression fixture 3830 as part of a larger assembly or system, such as a cushioning system (e.g., cushioning system 500 described above with reference to FIGS. 5 and 6).

[0237] 55 and 56 are front and rear views, respectively, of a fixed compression plate 4030 according to one suitable embodiment. The fixed compression plate 4030 includes a first or front side 5502 and a second or rear side 5504 opposite the first side 5502. The first side 5502 extends between the first side 5502 and the second side 5504 and is coupled to the second side 5504 by a perimeter 5506 that surrounds the perimeter of the fixed compression plate 4030. The perimeter 5506 includes an upper edge 5508, a lower edge 5510, and laterally opposed side edges 5512. The first side 5502 faces the battery receptacle 4402 when the fixed compression plate 4030 is assembled into a compression plate set 4050 with the moveable compression plate 4040. The first side 5502 is thereby positioned to engage a secondary battery disposed within the battery receptacle 4402. The first side 5502 is a substantially flat surface or plane to promote even distribution of pressure across a secondary battery disposed within the battery receptacle 4402. In the illustrated embodiment, the second side 5504 is also a substantially flat surface or plane.

[0238] The stationary compression plate 4030 of the exemplary embodiment includes a pair of flanges 5514 extending from laterally opposed side edges 5512. Each flange 5514 extends from a lower edge 5510 toward an upper edge 5508 of the stationary compression plate 4030 and is sized and shaped to be received within one of the compression plate channels 4310 defined in the base 4010 to couple the stationary compression plate 4030 to the base 4010. The flanges 5514 of the stationary compression plate 4030 can be used by the loading mechanism 3860 to facilitate moving the moveable compression plate 4040 toward and / or away from the stationary compression plate 4030 to load or unload a secondary battery in the battery receptacle 4402. For example, a portion of the loading mechanism 3860 may engage with a flange 5514 of the fixed compression plate 4030 to fix the loading mechanism 3860 and simultaneously engage with a portion of the moveable compression plate 4040 to move the moveable compression plate 4040.

[0239] The fixed compression plate 4030 also has a plurality of through holes 5516 defined therein and extending through the fixed compression plate 4030 from the first side 5502 to the second side 5504. Each through hole 5516 is sized and positioned on the fixed compression plate 4030 to align with and receive one of the alignment rods 4406. The fixed compression plate 4030 includes a number of through holes 5516 equal to the number of alignment rods 4406 of the compression fixture 3830, which is four in the illustrated embodiment. In other embodiments, the fixed compression plate 4030 may include more or less than four through holes.

[0240] 55, the first side 5502 of the fixed compression plate 4030 has one or more slots 5518 defined therein. The slots 5518 extend from an upper edge 5508 of the fixed compression plate 4030 toward a lower edge 5510 of the fixed compression plate 4030. Each slot 5518 is sized and shaped to receive a finger of a loading mechanism 3860 (described further herein) to facilitate loading and unloading of a secondary battery within the battery receptacle 4402. Although the illustrated fixed compression plate 4030 includes two laterally spaced apart slots 5518, other embodiments may include more or less than two slots 5518.

[0241] In some examples, the fixed compression plate 4030 may include a compliant material (e.g., foam, neoprene) disposed on a first side 5502 (i.e., the side facing the battery receptacle 4402 and the fixed compression plate 4030), for example, to facilitate applying even pressure across a surface of a secondary battery disposed within the battery receptacle 4402.

[0242] As shown in FIG. 56, the second side 5504 of the fixed compression plate 4030 has one or more spring recesses 5520 defined therein. Each spring recess 5520 is configured (e.g., sized and shaped) to receive at least a portion of a spring therein (e.g., spring 4408 shown in FIGS. 45 and 46). For example, each spring recess 5520 can receive a first end of one of the springs 4408 and hold the spring 4408 in place between the fixed compression plate 4030 of one set 4050 and the movable compression plate 4040 of an adjacent set 4050. The fixed compression plate 4030 includes a number of spring recesses 5520 equal to the number of springs 4408 in each compression plate set 4050, which is four in the illustrated embodiment. In other embodiments, the fixed compression plate 4030 may include more or less than four spring recesses 5520.

[0243] 57 and 58 are front and rear views, respectively, of a moveable compression plate 4040 according to one suitable embodiment. The moveable compression plate 4040 includes a first or front side 5702 and a second or rear side 5704 opposite the first side 5702. The first side 5702 extends between the first side 5702 and the second side 5704 and is coupled to the second side 5704 by a perimeter 5706 that surrounds the perimeter of the moveable compression plate 4040. The perimeter 5706 includes an upper edge 5708, a lower edge 5710, and laterally opposed side edges 5712. The first side 5702 faces the battery receptacle 4402 when the moveable compression plate 4040 is assembled into a compression plate set 4050 with the moveable compression plate 4040. The first side 5702 is thereby positioned to engage a secondary battery disposed within the battery receptacle 4402. The first side 5702 is a substantially flat surface or plane to promote even distribution of pressure across a secondary battery disposed within the battery receptacle 4402. In the illustrated embodiment, the second side 5704 is also a substantially flat surface or plane.

[0244] The movable compression plate 4040 of the exemplary embodiment includes a pair of flanges 5714 extending from laterally opposed side edges 5712. Each flange 5714 is spaced apart from the upper edge 5708 and the lower edge 5710 of the movable compression plate 4040 such that the flanges 5714 are located approximately midway between the upper edge 5708 and the lower edge 5710. Additionally, a bottom 5716 of each flange 5714 is spaced apart from the lower edge 5710 of the movable compression plate 4040 a sufficient distance such that when the movable compression plate 4040 is coupled to the base 4010, each flange 5714 is positioned adjacent to and / or in engagement with the upper surface 4036 of a respective rail 4118. 44-54 , for example, each flange 5714 of the moveable compression plate 4040 is sized and shaped such that each flange 5714 of the moveable compression plate 4040 abuts a portion of each flange 5514 of the fixed compression plate 4030 that extends over the compression plate channel 4310. The flanges 5714 of the moveable compression plate 4040 can be used by the loading mechanism 3860 to move the moveable compression plate 4040 toward and / or away from the fixed compression plate 4030 to load or unload a secondary battery in the battery receptacle 4402. For example, a portion of the loading mechanism 3860 can engage the flanges 5714 of the moveable compression plate 4040 to move the moveable compression plate 4040.

[0245] The movable compression plate 4040 also has a plurality of through holes 5718 defined therein and extending through the movable compression plate 4040 from the first side 5702 to the second side 5704. Each through hole 5718 is sized and positioned on the movable compression plate 4040 to align with and receive one of the alignment rods 4406. The movable compression plate 4040 includes a number of through holes 5718 equal to the number of alignment rods 4406 of the compression fixture 3830, which is four in the illustrated embodiment. In other embodiments, the movable compression plate 4040 may include more or less than four through holes.

[0246] As shown in FIG. 57 , the first side 5702 of the movable compression plate 4040 has one or more slots 5720 defined therein. The slots 5720 extend from an upper edge 5708 of the movable compression plate 4040 toward a lower edge 5710 of the movable compression plate 4040. Each slot 5720 is sized and shaped to receive a finger of a loading mechanism 3860 (described further herein) to facilitate loading and unloading of a secondary battery within the battery receptacle 4402. The illustrated movable compression plate 4040 includes two slots 5720 laterally spaced apart from one another, although other embodiments may include more or less than two slots 5720. In an exemplary embodiment, the slots 5720 of the movable compression plate 4040 have the same configuration (e.g., size, shape, and location) as the slots 5518 of the fixed compression plate 4030.

[0247] In this embodiment, the first side 5702 of the moveable compression plate 4040 also includes a spacer 4410. More specifically, each spacer 4410 is integrally formed with the moveable compression plate 4040 and is concentric with one of the through holes 5718 of the moveable compression plate 4040. In this embodiment, each spacer 4410 is annular and each defines a through hole that is aligned with a corresponding through hole 5718 of the moveable compression plate 4040. As mentioned above, in other embodiments, the spacers 4410 may be formed separately from the moveable compression plate 4040 and / or positioned other than concentric with the through holes 5718.

[0248] In some examples, the movable compression plate 4040 may include a compliant material (e.g., foam, neoprene) disposed on a first side 5702 (i.e., the side facing the battery receptacle 4402 and the fixed compression plate 4030), for example, to facilitate applying even pressure across a surface of a secondary battery disposed within the battery receptacle 4402.

[0249] As shown in FIG. 58 , the second side 5704 of the movable compression plate 4040 has one or more spring recesses 5722 defined therein. Each spring recess 5722 is configured (e.g., sized and shaped) to receive at least a portion of a spring therein (e.g., spring 4408 shown in FIGS. 45 and 46 ). For example, each spring recess 5722 can receive a second end of one of the springs 4408 and hold the spring 4408 in position between the movable compression plate 4040 of one set 4050 and the fixed compression plate 4030 of an adjacent set 4050. The movable compression plate 4040 includes a number of spring recesses 5722 equal to the number of springs 4408 in each compression plate set 4050, which is four in the illustrated embodiment. In other embodiments, the movable compression plate 4040 may include more or less than four spring recesses 5722. Each spring recess 5722 on the movable compression plate 4040 is aligned with and faces one of the spring recesses 5520 on the fixed compression plate 4030 when the fixed compression plate 4030 and the movable compression plate 4040 are coupled to the base 4010.

[0250] 43-46, the compression fixture 3830 may be assembled by coupling the fixed compression plate 4030 and the movable compression plate 4040 to the base 4010, disposing a spring 4408 between each movable compression plate 4040 and the fixed compression plate 4030 of an adjacent set 4050, and inserting the alignment rod 4406 into the through holes 5516 and 5718 of the fixed compression plate 4030 and the movable compression plate 4040. The springs 4408 may be disposed between the movable compression plate 4040 and the fixed compression plate 4030, for example, by inserting a first end of each spring 4408 into one of the spring recesses 5520 of the fixed compression plate 4030 and an opposite second end of the spring 4408 into one of the spring recesses 5722 of the movable compression plate 4040. The fixed compression plates 4030 may be coupled to the base 4010, for example, by inserting a flange 5514 of each fixed compression plate 4030 into a corresponding compression plate channel 4310 ( FIG. 43 ) of the base 4010. When the fixed compression plates 4030 are coupled to the base 4010, a second side 5504 ( FIG. 56 ) of each fixed compression plate 4030 engages one of the stops 4314 of the base 4010. When the movable compression plate 4040 is coupled to the base 4010, the flange 5714 of each movable compression plate 4040 is disposed on and / or adjacent to the upper surface 4306 of the rail 4118. Positioning the movable compression plate 4040 within the base 4010 in this manner allows the movable compression plate 4040 to move linearly in the longitudinal direction x (e.g., in response to actuation by the loading mechanism 3860). In this embodiment, linear or longitudinal movement of each movable compression plate 4040 away from the fixed compression plate 4030 of the same set 4050 is limited by one of the stops 4314. For example, as the movable compression plate 4040 moves away from the fixed compression plate 4030 (e.g., during insertion or removal of a secondary battery in the battery receptacle 4402), the second side 5704 of the movable compression plate 4040 will engage the stopper 4314, which inhibits further longitudinal or linear movement of the movable compression plate 4040 away from the fixed compression plate 4030.

[0251] 38 , the exemplary embodiment includes a loading mechanism 3860 that facilitates loading and unloading of the secondary battery within the compression fixture 3830. For example, the loading mechanism 3860 of the exemplary embodiment is configured to load the secondary battery 5100 into the compression fixture 3830 (e.g., after a formation process and / or a pre-lithiation process) and remove the secondary battery 5100 from the compression fixture 3830. More specifically, the loading mechanism 3860 is configured to interact with each moveable compression plate 4040 and / or each fixed compression plate 4030 of the compression fixture 3830 to move each moveable compression plate 4040 from a first position to a second position to increase the size or width 4404 of the battery receptacle 4402 such that the secondary battery 5100 may be inserted into or removed from the battery receptacle 4402. Additionally, the loading mechanism 3860 is configured to interact with each movable compression plate 4040 and / or each fixed compression plate 4030 of the compression fixture 3830 to enable movement of each movable compression plate 4040 from the second position to the first position (e.g., by releasing or otherwise disengaging the movable compression plate 4040 under the force of the spring 4408) to engage and compress the secondary battery 5100 disposed within the battery receptacle 4402. Additionally, the illustrated loading mechanism 3860 is further configured to insert the secondary battery 5100 into the battery receptacle 4402 of the compression fixture 3830 and remove the secondary battery from the battery receptacle 4402 of the compression fixture 3830. The loading mechanism 3860 may include any suitable actuators, motors, mechanical linkages, controllers, and other components to enable the loading mechanism 3860 to function as described herein. In some embodiments, the loading mechanism 3860 includes or is coupled to a positioning system operable to move the loading mechanism 3860 longitudinally, laterally, and / or vertically relative to the compression fixture 3830.In some embodiments, the loading mechanism 3860 is movable longitudinally along the length of the compression fixture 3830 such that the loading mechanism 3860 can interact (e.g., move, grab, push, pull, etc.) with the movable compression plates 4040 of each compression plate set 4050. In one embodiment, for example, the loading mechanism 3860 is mounted to an XY positioning system operable to move the loading mechanism 3860 in a plane parallel to the base 4010 of the compression fixture 3830 (e.g., longitudinally and laterally relative to the compression fixture 3830).

[0252] 59, the example loading mechanism 3860 includes a bracket 5910, one or more plate spreaders 5920 coupled to the bracket 5910, and a battery clamp 5930 coupled to the bracket 5910. In this embodiment, the battery clamp 5930 is coupled to the bracket 5910 by a linear actuator 5940 operable to raise and lower the battery clamp 5930 (e.g., toward and away from the compression fixture 3830 and the battery receptacle 4402).

[0253] 60 and 61 are enlarged perspective views of the loading mechanism 3860, and FIG. 62 is an enlarged side view of the loading mechanism 3860. As shown in FIGS. 60-62, the battery clamp 5930 includes two pairs 6002 of elongated fingers 6004 operable to clamp the secondary battery 5100 between the fingers 6004 of one pair 6002 and the fingers 6004 of the other pair 6002. Each finger 6004 of one pair 6002 is disposed opposite and parallel to one of the fingers 6004 of the other pair 6002. One or both pairs 6002 of fingers 6004 may be coupled to an actuator operable to move the pairs 6002 of fingers 6004 toward or away from each other to clamp the secondary battery 5100 between the pairs 6002 of fingers 6004 and release the secondary battery 5100. That is, one or both pairs 6002 of fingers 6004 may be movable toward and away from the other pair 6002 of fingers 6004 to facilitate clamping and releasing the secondary battery 5100 from the battery clamp 5930. In this example, each pair 6002 of fingers 6004 is coupled to a respective linear actuator (not shown) operable to move the pair 6002 of fingers 6004 toward or away from the other pair 6002 of fingers 6004. In other embodiments, only one pair 6002 of fingers 6004 may be movable (e.g., via a suitable actuator) and the other pair 6002 of fingers 6004 may be fixed or stationary. In other embodiments, any other suitable mechanism may be used to hold and release the secondary battery that enables the cell formation system 3800 to function as described herein.

[0254] 63 is another enlarged perspective view of the loading mechanism 3860 separated from the compression fixture 3830 showing details of the plate spreaders 5920. The exemplary loading mechanism 3860 includes two plate spreaders 5920 laterally spaced apart from one another and positioned in opposing relationship. When the loading mechanism 3860 interacts with the compression fixture 3830, one plate spreader 5920 is disposed on one side of the compression plate 4020 and the other plate spreader 5920 is disposed on the other side of the compression plate 4020 such that the compression plate 4020 is disposed between the two plate spreaders 5920. Other embodiments may include more or less than two plate spreaders 5920. Details of a single plate spreader 5920 are described below, but it should be understood that the other plate spreaders 5920 may have the same or substantially the same structure and operate in the same or substantially the same manner.

[0255] As shown in FIG. 63, the plate spreader 5920 includes a guide 6302 defining an elongated slot 6304, a movable tab 6306 disposed within the slot 6304 for linear movement within the slot 6304, and an actuator 6308 coupled to the guide 6302 and the movable tab 6306. In this embodiment, the actuator 6308 is a linear actuator that is operably coupled to the movable tab 6306 (e.g., via a shaft, not shown) to move the tab between a first position (shown in FIG. 63 as transparent) and a second position (shown in FIG. 63 as solid lines). The movable tab 6306 protrudes from the elongated slot 6304 and is positioned to engage one of the movable compression plates 4040 to move the movable compression plate 4040 (e.g., from the first position to or toward the second position). More specifically, the movable tab 6306 is positioned to engage one of the flanges 5714 of the movable compression plate 4040 to move the movable compression plate 4040 linearly or longitudinally along the alignment rod 4406. For example, when the movable tab 6306 is positioned adjacent to and / or engaged with a flange 5714 of the movable compression plate 4040, actuation of the actuator 6308 causes the movable tab 6306 to move from a first position to a second position, thereby moving the movable compression plate 4040 toward the second position (i.e., away from the fixed compression plate 4030). In some embodiments, the thickness of the movable tab 6306 is less than the thickness or height of a spacer 4410 (FIGS. 44-46) positioned between the fixed compression plate 4030 and the movable compression plate 4040 of each compression plate set 4050, such that the movable tab 6306 can be positioned or inserted between the fixed compression plate 4030 and the movable compression plate 4040 when the movable compression plate 4040 is in a first position (i.e., the position closest to the fixed compression plate 4030).

[0256] The plate spreaders 5920 may also be movable relative to the compression fixture 3830 and compression plate 4020 such that each plate spreader 5920 can be moved (e.g., laterally and / or vertically) toward and away from the compression plate 4020 to facilitate positioning the movable tab 6306 of the plate spreader 5920 between the movable compression plate 4040 and the fixed compression plate 4030 of the compression plate set 4050. With reference to FIG. 64, for example, each plate spreader 5920 in the illustrated embodiment is coupled to the bracket 5910 by a lift mechanism 6400 operable to raise and lower the plate spreader 5920 relative to the compression fixture 3830. The exemplary lift mechanism 6400 includes a yoke 6402 slidably coupled to a bracket 5910 and an actuator 6404 coupled to the bracket 5910 and operably coupled to the yoke 6402 to move or slide the yoke 6402 along the bracket 5910 toward and away from the compression fixture 3830. Each plate spreader 5920 is coupled to the yoke 6402 via a respective arm 6406. The actuator 6404 is coupled to the yoke 6402 via one of the arms 6406 in this embodiment, but in other embodiments the actuator 6404 may be coupled directly to the yoke 6402 or via other suitable mechanical linkages. Actuation of the actuator 6404 raises and lowers the yoke 6402 and the plate spreader 5920 relative to the compression fixture 3830 such that the movable tab 6306 of the plate spreader 5920 may be positioned between the movable compression plate 4040 and the stationary compression plate 4030 of the compression plate set 4050. For example, after the loading mechanism 3860 loads a secondary battery into the battery receptacle 4402 of one of the compression plate sets 4050, the plate spreader 5920 may be raised by the lift mechanism 6400 above the movable compression plate 4040 and the fixed compression plate 4030 of that set 4050, so that the plate spreader 5920 can be moved longitudinally (e.g., via an XY positioning system) relative to the compression fixture 3830 and positioned above another compression plate set 4050.When the plate spreader 5920 is to be placed on top of another compression plate set 4050, the actuator 6404 can be actuated again to lower the yoke 6402 and the plate spreader 5920 towards the compression fixture 3830 so that the movable tabs 6306 of the plate spreader 5920 are positioned between the movable compression plate 4040 and the fixed compression plate 4030 of the compression plate set 4050.

[0257] Actuators of the loading mechanism 3860 may include, for example, electrically controllable actuators including, but not limited to, pneumatic actuators, electric motors, servo motors, stepper motors, and combinations thereof. Such electrically controllable actuators may include and / or be communicatively coupled to suitable one or more controllers (e.g., controller 3004, controller 3110, and / or a dedicated loading mechanism controller) to control operation of the loading mechanism 3860. In some embodiments, for example, one or more actuators of the loading mechanism 3860 may include and / or be communicatively coupled to one or more controllers for automatic or semi-automatic control of the loading mechanism 3860. For example, the one or more controllers may be programmed to control the actuators of the loading mechanism 3860 to perform one or more operations described herein, including, but not limited to, for example, transporting a secondary battery to the compression fixture 3830, loading the secondary battery into the battery receptacle 4402 of the compression fixture 3830, removing the secondary battery 5100 from the battery receptacle 4402 of the compression fixture 3830, moving the moveable compression plate 4040 (e.g., from a first position to a second position), releasing or disengaging the moveable compression plate from the loading mechanism 3860, and any other process or operation described herein.

[0258] In operation, the compression fixture 3830 is used to apply a compressive force to the secondary batteries, for example, during the formation and / or pre-lithiation process of the secondary batteries. For example, the loading mechanism 3860 can transport one or more secondary batteries 5100 to the compression fixture 3830 and insert the secondary batteries 5100 into corresponding battery receptacles 4402 of the compression fixture 3830. The secondary batteries 5100 may be stored in any suitable location prior to being transported to the compression fixture 3830. For example, the secondary batteries 5100 may be stored in a battery tray (e.g., battery tray 2202 or battery tray 3810) or in a separate row of battery slots 3820 of the tray 3810 to which the compression fixture 3830 is mated.

[0259] To transport the secondary battery 5100 to the compression fixture 3830, the loading mechanism 3860 may be positioned adjacent to (e.g., above) one of the secondary batteries 5100 via a suitable positioning system (e.g., an XY positioning system). The battery clamp 5930 may then be lowered or otherwise positioned relative to the secondary battery 5100 (e.g., via a linear actuator 5940) such that the secondary battery 5100 is positioned between the pair 6002 of the fingers 6004 of the battery clamp 5930. The battery clamp 5930 may then be actuated to cause the pair 6002 of the fingers 6004 to clamp the secondary battery 5100 therebetween, thereby securing the secondary battery 5100 by the battery clamp 5930. The battery clamp 5930 may then be raised with the secondary battery 5100 secured thereto, and the compression fixture 3830 may then be positioned adjacent to the loading mechanism 3860, thereby loading the secondary battery 5100 therein.

[0260] In the illustrated embodiment, the secondary battery 5100 is loaded into the compression fixture 3830 as part of a cushioning system (e.g., cushioning system 500). Thus, the battery clamp 5930 can engage an enclosure or other portion of the cushioning system instead of directly engaging the secondary battery 5100. In the illustrated embodiment, for example, the fingers 6004 of the battery clamp 5930 engage the cushioning system's enclosure (e.g., film) on the left and right sides of the secondary battery. In other embodiments, the battery clamp 5930 may directly engage the secondary battery 5100. In still other embodiments, the secondary battery 5100 may be loaded into a compression fixture 3830 that is separate from or distinct from the cushioning system.

[0261] When a secondary battery is transported to or from the compression fixture 3830, the plate spreader 5920 may be maintained in a raised position (e.g., via a lift mechanism 6400), e.g., to avoid interference with the compression fixture 3830 and / or other secondary batteries. To load the secondary battery 5100 into the compression fixture 3830, a loading mechanism 3860 having the secondary battery 5100 secured by battery clamps 5930 may be positioned adjacent to the compression fixture 3830. For example, the loading mechanism 3860 may be positioned above the compression fixture 3830 with the secondary battery 5100 vertically aligned with the battery receptacle 4402 of one of the compression plate sets 4050 and the movable tab 6306 of each plate spreader 5920 vertically aligned with the space or gap between the corresponding flanges (e.g., flanges 5514 and 5714) of the stationary compression plate 4030 and the movable compression plate 4040 of the compression plate set 4050. The plate spreaders 5920 may then be lowered or moved (e.g., via the lift mechanism 6400) such that the movable tab 6306 of each plate spreader 5920 is positioned between the corresponding flanges (e.g., flanges 5514 and 5714) of the movable compression plate 4040 and the stationary compression plate 4030 of the compression plate set 4050. The actuator 6308 of each plate spreader 5920 can operate to engage the movable tabs 6306 with corresponding flanges 5714 of the movable compression plate 4040 and move the movable compression plate 4040 away from the fixed compression plate 4030 (e.g., from a first position to a second position) to increase the size or width of the battery receptacle 4402.

[0262] The secondary battery 5100 may then be lowered or moved by the battery clamps 5930 (e.g., via actuation of the linear actuators 5940) into the battery receptacle 4402 while the moveable compression plate 4040 is held in position (e.g., the second position) by the plate spreader 5920. For example, the secondary battery 5100 may be lowered into the battery receptacle 4402 until a portion of the secondary battery 5100 contacts the concave surface 4308 of the base 4010. For example, as shown in FIG. 59 , when the secondary battery 5100 is placed into the battery receptacle 4402, the first electrical terminal 5102 (e.g., electrical terminal 124) and the second electrical terminal 5104 (e.g., electrical terminal 125) of the secondary battery 5100 may extend through corresponding battery openings 4312 in the base 4010. The first electrical terminal 5102 and the second electrical terminal 5104 of the secondary battery 5100 may also extend through one of the battery slots 3820 of the battery tray 3810 aligned with the battery opening 4312 of the compression fixture base 4010. As described above, in this embodiment, the secondary battery 5100 is loaded into the compression fixture 3830 as part of a buffer system. Thus, the third terminal 5106 electrically connected to an auxiliary electrode (e.g., conductive tab 508-1) of the buffer system may also extend through the battery opening 4312 and the battery slot 3820. Thus, the terminals of the secondary battery 5100 are easily accessible and connectable to other components of the cell formation system 3800, for example, to perform one or more of the formation and / or pre-lithiation processes described herein.

[0263] When the secondary battery 5100 is placed in the battery receptacle 4402, the plate spreader 5920 can be released or otherwise disengaged from the moveable compression plate 4040, for example, by actuating the plate spreader actuator 6308 to move the moveable tabs 6306 away from the moveable compression plate 4040 of the set 4050 and / or toward the fixed compression plate 4030. Releasing the moveable compression plate 4040 allows the moveable compression plate 4040 to move toward the secondary battery 5100 under the force of the springs 4408 and engage the secondary battery 5100. The secondary battery 5100 is then compressed between the moveable compression plate 4040 and the fixed compression plate 4030.

[0264] The battery clamp 5930 can release the secondary battery 5100, for example, by actuating the battery clamp 5930 to move the pair 6002 of fingers 6004 away from each other. The battery clamp 5930 can release the secondary battery 5100 before, during (i.e., simultaneously with), or after the plate spreader 5920 releases or disengages the moveable compression plate 4040. In one example, the battery clamp 5930 releases the secondary battery 5100 after the moveable compression plate 4040 is released from the plate spreader 5920 and engages the secondary battery 5100. In this example, the fingers 6004 of the battery clamp 5930 may be positioned within the slots 5518 of the fixed compression plate 4030 ( FIG. 55 ) and / or the slots 5720 of the movable compression plate 4040 ( FIG. 57 ), for example, to prevent interference between the fingers 6004 and the fixed compression plate 4030 and the movable compression plate 4040 and to enable the battery clamp 5930 to be removed from the battery receptacle 4402 after the secondary battery 5100 is placed therein.

[0265] Once the secondary battery 5100 is released from the battery clamps 5930, the battery clamps 5930 may be lifted or otherwise moved out of the battery receptacle 4402, for example, by actuation of the linear actuator 5940. The plate spreader 5920 may also be lifted or otherwise moved out and / or away from the battery receptacle 4402 (e.g., via the lift mechanism 6400) to allow movement of the loading mechanism 3860 to a position where additional secondary batteries are stored. The above process may be repeated to load additional secondary batteries 5100 into the compression fixture 3830.

[0266] While the secondary batteries 5100 are held within the compression fixture 3830, each secondary battery 5100 is compressed between the fixed compression plate 4030 and the movable compression plate 4040 of the compression plate set 4050. The amount of compression is based, at least in part, on the type and number of springs 4408 included in each compression plate set 4050. For example, the amount of compression can be increased or decreased by utilizing springs having a higher or lower spring constant and / or by utilizing a greater or lesser number of springs 4408. Additionally, the compression force applied to the secondary battery 5100 can be selected based on one or more of the size of the secondary battery 5100, the geometry of the secondary battery 5100, the structure of the secondary battery 5100, and one or more processes (e.g., formation and / or pre-lithiation processes) the secondary battery 5100 undergoes while in the compression fixture 3830. In some embodiments, each compression plate set 4050 is configured (i.e., has an appropriate number and type of springs 4408) to apply a compressive force across the surface of the secondary battery 5100 equal to a pressure in the range of 1 pound per square inch (PSI) to 10 PSI, in the range of 1 PSI to 8 PSI, in the range of 2 PSI to 10 PSI, in the range of 1 PSI to 6 PSI, in the range of 2 PSI to 8 PSI, in the range of 3 PSI to 10 PSI, in the range of 2 PSI to 6 PSI, in the range of 3 PSI to 8 PSI, in the range of 4 PSI to 10 PSI, or in the range of 3 PSI to 6 PSI.

[0267] Additionally, as described above, the terminals of the secondary batteries 5100 may be connected to one or more components of the cell formation system 3800 to perform one or more processes on the secondary batteries 5100 while they are held in the compression fixture 3830. In some embodiments, for example, the terminals of each secondary battery 5100 are connected to a pre-lithiation module (e.g., pre-lithiation module 2216 and / or pre-lithiation module 3104) and the secondary batteries undergo a pre-lithiation process while they are held in the compression fixture 3830.

[0268] The secondary battery 5100 can be removed from the compression fixture 3830 in a similar manner to how it was loaded. For example, the loading mechanism 3860 may be positioned above the compression fixture 3830 with the fingers 6004 of the battery clamps 5930 vertically aligned with the battery receptacle 4402 of one of the compression plate sets 4050 and the moveable tabs 6306 of each plate spreader 5920 vertically aligned with the space or gap between corresponding flanges (e.g., flanges 5514 and 5714) of the fixed and moveable compression plates 4030 and 4040 of the compression plate set 4050. The plate spreaders 5920 may then be lowered or moved (e.g., via the lift mechanism 6400) such that the movable tab 6306 of each plate spreader 5920 is disposed between a corresponding flange (e.g., flanges 5514 and 5714) of the movable compression plate 4040 and the fixed compression plate 4030 of the compression plate set 4050. The actuator 6308 of each plate spreader 5920 may operate to engage the movable tab 6306 with the corresponding flange 5714 of the movable compression plate 4040 and move the movable compression plate 4040 away from the fixed compression plate 4030 (e.g., to a second position) to increase the size or width of the battery receptacle 4402 and disengage the movable compression plate 4040 from the secondary battery 5100.

[0269] The battery clamp 5930 may be lowered or otherwise moved (e.g., via a linear actuator 5940) such that the secondary battery 5100 is disposed between the pair 6002 of fingers 6004 of the battery clamp 5930. In some embodiments, the battery clamp 5930 is lowered by the linear actuator 5940 before the plate spreader 5920 moves the moveable compression plate 4040 such that the secondary battery 5100 is held in place until the battery clamp 5930 clamps the secondary battery 5100. In such embodiments, the fingers 6004 of the battery clamp 5930 may be inserted into the slots 5518 of the fixed compression plate 4030 ( FIG. 55 ) and / or the slots 5720 of the moveable compression plate 4040 ( FIG. 57 ) when the clamp 5930 is lowered by the linear actuator 5940 towards the compression fixture 3830. When the secondary battery 5100 is placed between the pair 6002 of fingers 6004 of the battery clamp 5930, the battery clamp 5930 can be actuated to cause the pair 6002 of fingers 6004 to clamp the secondary battery 5100 between them, thereby securing the secondary battery 5100 by the battery clamp 5930. If not already moved, the plate spreader 5920 can move the moveable compression plate 4040 away from the fixed compression plate 4030 and the secondary battery 5100. The battery clamp 5930 can then be raised along with the secondary battery 5100 secured thereto, thereby removing the secondary battery 5100 from the battery receptacle 4402. The plate spreader 5920 can also be lifted or otherwise moved out and / or away from the battery receptacle 4402 (e.g., via the lift mechanism 6400) to allow the loading mechanism 3860 to move to another location and transport the secondary battery 5100 thereto. The above process can be repeated to unload additional secondary batteries 5100 from the compression fixture 3830.

[0270] 66 is a flowchart of an exemplary method 6600 of compressing a lithium-containing secondary battery according to one suitable embodiment. The method 6600 can be performed by or within a cell formation system, such as, for example, the cell formation system 3800 shown and described with reference to FIGS.

[0271] The method 6600 begins 6610 when a loading mechanism (e.g., loading mechanism 3860) interacts with a movable compression plate and a fixed compression plate of a compression fixture (e.g., compression fixture 3830). As described above, the fixed compression plate and the movable compression plate define a battery receptacle having an associated width. The loading mechanism may be movable along the length of the compression fixture as secondary batteries are loaded and / or removed from the battery receptacle.

[0272] As part of this interaction, the loading mechanism can interface with one or more flanges of the movable compression plate and / or the fixed compression plate such that the movable compression plate is moved from a first position to a second position (6620). For example, the loading mechanism can insert a movable tab into a battery receptacle and / or push or pull the movable compression plate away from the fixed compression plate.

[0273] As the movable compression plate is moved from the first position to the second position, the secondary battery is loaded (or unloaded) from the battery receptacle 6630. The loading mechanism then moves the movable compression plate from the second position toward the first position 6640. As a result, a compressive force is applied to the secondary battery.

[0274] 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.

[0275] Embodiment 1: A cell formation system for a lithium-containing secondary battery, each of which 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, wherein each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure. The cell formation system includes a compression fixture and a loading mechanism. The compression fixture includes a base and a plurality of compression plate sets coupled to the base, each compression plate set including a stationary compression plate, a movable compression plate movable relative to the stationary compression plate between a first position and a second position, and at least one spring operably coupled to the movable compression plate. The movable compression plate is disposed farther from the stationary compression plate at the second position than at the first position, wherein the stationary compression plate and the movable compression plate define a battery receptacle therebetween for receiving a lithium-containing secondary battery. The at least one spring biases the movable compression plate toward the fixed compression plate to apply a compressive force to the lithium-containing secondary battery when disposed in the battery receptacle, and the loading mechanism includes at least one plate spreader operable to move the movable compression plate away from the fixed compression plate for loading and unloading the lithium-containing secondary battery in the battery receptacle.

[0276] Embodiment 2: A cell formation system as described in embodiment 1, wherein the base defines a plurality of battery openings, each battery opening being aligned with a battery receptacle of a corresponding compression plate set, and wherein the first terminal and the second terminal of the lithium-containing secondary battery extend through one of the battery openings when the lithium-containing secondary battery is placed in the battery receptacle of the corresponding compression plate set.

[0277] Embodiment 3: The cell formation system of embodiment 2, wherein each lithium-containing secondary battery further includes an auxiliary electrode and a conductive tab electrically connected to the auxiliary electrode, wherein the conductive tab of the lithium-containing secondary battery extends through one of the battery openings when the lithium-containing secondary battery is placed in a battery receptacle of the corresponding compression plate set.

[0278] Embodiment 4: The cell formation system of any one of the preceding embodiments, further comprising a battery tray, wherein the compression fixture is removably coupled to the battery tray.

[0279] Embodiment 5: A cell formation system as described in embodiment 4, wherein the battery tray defines a plurality of battery slots, and wherein when the lithium-containing secondary battery is placed in the battery receptacle of one of the compression plate sets and the compression fixture is coupled to the battery tray, the first terminal and the second terminal of the lithium-containing secondary battery extend through one of the battery slots.

[0280] Embodiment 6: The cell formation system of embodiment 5, wherein each lithium-containing secondary battery further includes an auxiliary electrode and a conductive tab electrically connected to the auxiliary electrode, and when the lithium-containing secondary battery is placed in the battery receptacle of one of the compression plate sets and the compression fixture is coupled to the battery tray, the conductive tab of the lithium-containing secondary battery extends through one of the battery slots.

[0281] Embodiment 7: A cell formation system described in any one of the previous embodiments, wherein the movable compression plate of each compression plate set includes a first side facing the fixed compression plate and an opposing second side facing in an opposite direction from the fixed compression plate, wherein the movable compression plate includes a compliant material disposed on the first side.

[0282] Embodiment 8: A cell formation system described in any one of the preceding embodiments, wherein the fixed compression plate of each compression plate set includes a first side facing the movable compression plate and an opposing second side facing in an opposite direction from the movable compression plate, wherein the fixed compression plate includes a compliant material disposed on the first side.

[0283] Embodiment 9: A cell formation system described in any one of the preceding embodiments, wherein each compression plate set further includes at least one spacer disposed between the fixed compression plate and the movable compression plate, the at least one spacer maintaining a minimum distance between the fixed compression plate and the movable compression plate.

[0284] Embodiment 10: The cell formation system of embodiment 9, wherein the at least one plate spreader includes a movable tab operable to engage the movable compression plate and move the movable compression plate from the first position to the second position, wherein a thickness of the movable tab is less than a thickness of the spacer.

[0285] Embodiment 11: A cell formation system described in any one of the preceding embodiments, wherein the at least one spring is positioned between the movable compression plate of one compression plate set and the fixed compression plate of an adjacent compression plate set.

[0286] Embodiment 12: A cell formation system described in any one of the preceding embodiments, further comprising at least one alignment rod, wherein each of the fixed compression plate and the movable compression plate defines at least one through hole, and wherein the at least one alignment rod extends through the at least one through hole of each fixed compression plate and each movable compression plate.

[0287] Embodiment 13: A cell formation system described in any one of the preceding embodiments, wherein the movable compression plate of each compression plate set includes at least one flange, and wherein the plate spreader is operable to engage with the at least one flange to move the movable compression plate from the first position to the second position.

[0288] Embodiment 14: A cell formation system described in any one of the preceding embodiments, wherein the loading mechanism further includes a battery clamp operable to clamp the lithium-containing secondary battery and place the lithium-containing secondary battery in the battery receptacle.

[0289] Embodiment 15: A lithium-containing secondary battery formed using the cell formation system of any one of the preceding embodiments, the lithium-containing secondary battery comprising: a population of unit cells, an electrode bus bar, a counter electrode bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter electrode bus bar, wherein each unit cell of the population of unit cells comprises an electrode structure, a separator structure, and a counter electrode structure, the electrode structure of each member of the population of unit cells comprises an electrode current collector and an electrode active material layer, and the counter electrode structure of each member of the population of unit cells comprises a counter electrode current collector and a counter electrode active material layer.

[0290] Embodiment 16: The lithium-containing secondary battery of embodiment 15, further comprising an auxiliary electrode, an enclosure surrounding the group of unit cells, the electrode bus bar, the counter electrode bus bar, and the auxiliary electrode, and a conductive tab electrically connected to the auxiliary electrode, wherein the first terminal, the second terminal, and the conductive tab extend from the enclosure.

[0291] Embodiment 17: A compression fixture for a lithium-containing secondary battery, each of which 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, each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure, the compression fixture comprising a base and a plurality of compression plate sets coupled to the base, each compression plate set including a fixed compression plate and a movable compression plate movable relative to the fixed compression plate between a first position and a second position, the movable compression plate being movable relative to the fixed compression plate between a first position and a second position. a dynamic compression plate disposed farther from the fixed compression plate at the second position than at the first position, wherein the fixed compression plate and the movable compression plate define a battery receptacle therebetween for receiving a lithium-containing secondary battery, and a compression plate set including: a dynamic compression plate; and at least one spring operatively coupled to the movable compression plate and biasing the movable compression plate toward the fixed compression plate so as to apply a compressive force to the lithium-containing secondary battery when disposed within the battery receptacle.

[0292] Embodiment 18: The compression fixture of embodiment 17, wherein the base defines a plurality of battery openings, each battery opening being aligned with a battery receptacle of a corresponding compression plate set, and wherein the first terminal and the second terminal of the lithium-containing secondary battery extend through one of the battery openings when the lithium-containing secondary battery is placed in the battery receptacle of the corresponding compression plate set.

[0293] Embodiment 19: The compression fixture of embodiment 18, wherein each lithium-containing secondary battery further includes an auxiliary electrode and a conductive tab electrically connected to the auxiliary electrode, and wherein the conductive tab of the lithium-containing secondary battery extends through one of the battery openings when the lithium-containing secondary battery is placed in a battery receptacle of the corresponding compression plate set.

[0294] Embodiment 20: A compression fixture described in any one of the preceding embodiments, wherein each compression plate set further includes at least one spacer disposed between the fixed compression plate and the movable compression plate, the at least one spacer maintaining a minimum distance between the fixed compression plate and the movable compression plate.

[0295] Embodiment 21: A compression fixture described in any one of the previous embodiments, wherein the at least one spring is disposed between the movable compression plate of one compression plate set and the fixed compression plate of an adjacent compression plate set.

[0296] Embodiment 22: A compression fixture described in any one of the preceding embodiments, further comprising at least one alignment rod, wherein each of the fixed compression plate and the movable compression plate defines at least one through hole, and wherein the at least one alignment rod extends through the at least one through hole of each fixed compression plate and each movable compression plate.

[0297] Embodiment 23: A compression fixture described in any one of the preceding embodiments, wherein the movable compression plate of each compression plate set includes a first side facing the fixed compression plate and an opposing second side facing in an opposite direction from the fixed compression plate, wherein the movable compression plate includes a compliant material disposed on the first side.

[0298] Embodiment 24: A compression fixture described in any one of the preceding embodiments, wherein the fixed compression plate of each compression plate set includes a first side facing the movable compression plate and an opposing second side facing in a direction away from the movable compression plate, wherein the fixed compression plate includes a compliant material disposed on the first side.

[0299] Embodiment 25: A method for manufacturing a lithium-containing secondary battery, each of which includes a population of unit cells, an electrode bus bar, a counter electrode bus bar, a first terminal electrically connected to the electrode bus bar, and a second terminal electrically connected to the counter electrode 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 comprising the steps of: moving a movable compression plate of a compression plate set from a first position to a second position, the compression plate set including a fixed compression plate, the movable compression plate, and at least one biasing member for biasing the movable compression plate toward the fixed compression plate. and at least one spring, the fixed compression plate and the movable compression plate defining a battery receptacle therebetween, wherein the movable compression plate is positioned farther from the fixed compression plate in the second position than in the first position; placing a lithium-containing secondary battery in the battery receptacle; and moving the movable compression plate toward and engaging the lithium-containing secondary battery such that the lithium-containing secondary battery is compressed between the fixed compression plate and the movable compression plate.

[0300] Embodiment 26: The method of embodiment 25, wherein the compression plate set is coupled to a base of a compression fixture, and wherein the step of placing a lithium-containing secondary battery in the battery receptacle includes a step of placing the first terminal and the second terminal of the lithium-containing secondary battery through a battery opening defined in the base and aligned with the battery receptacle.

[0301] Embodiment 27: The method of embodiment 26, wherein each lithium-containing secondary battery further includes an auxiliary electrode and a conductive tab electrically connected to the auxiliary electrode, and wherein placing the lithium-containing secondary battery in the battery receptacle further includes placing the conductive tab of the lithium-containing secondary battery through the battery opening.

[0302] Embodiment 28: The method of any one of the preceding embodiments, further comprising the step of performing a pre-lithiation process on the lithium-containing secondary battery while the lithium-containing secondary battery is compressed between the movable compression plate and the fixed compression plate.

[0303] Embodiment 29: The method of embodiment 28, further comprising removing the lithium-containing secondary battery from the battery receptacle after the pre-lithiation process.

[0304] Embodiment 30: A method according to any one of the preceding embodiments, wherein the step of moving a movable compression plate of a compression plate set from a first position to a second position includes a step of engaging a flange of the movable compression plate with a plate spreader of a loading mechanism, and a step of using the plate spreader to move the movable compression plate from the first position to the second position.

[0305] Embodiment 31: A secondary battery assembly formed using any of the above-described embodiments of the cell formation system, compression fixture, and / or method for manufacturing a lithium-containing secondary battery.

[0306] Embodiment 32. A secondary battery assembly as described in embodiment 31, wherein the electrode assembly of the battery assembly includes a rectangular prism shape.

[0307] Embodiment 33. 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 portion.

[0308] Embodiment 34. The electrode assembly is 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; or (c) Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, or Cd. (d) oxides, carbides, nitrides, sulfides, phosphides, selenides, and tellurides of Li, and mixtures, composites, or lithium-containing composites thereof; (e) salts and hydroxides of Sn; (f) particles of graphite and carbon; (g) lithium metal; and (h) combinations thereof.

[0309] Embodiment 35. 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 (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd).

[0310] Embodiment 36. 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 alloys and intermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements.

[0311] Embodiment 37. 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.

[0312] Embodiment 38. 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.

[0313] Embodiment 39. 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.

[0314] Embodiment 40. A secondary battery assembly according to any one of the preceding embodiments, wherein the electrode assembly comprises a positive electrode active material comprising lithium metal.

[0315] Embodiment 41. 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.

[0316] Embodiment 42. 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.

[0317] Embodiment 43. 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.

[0318] Embodiment 44. A secondary battery assembly as described in any one of the preceding embodiments, wherein the secondary battery further includes a polymer electrolyte within the enclosure.

[0319] Embodiment 45. A secondary battery assembly as described in any one of the preceding embodiments, wherein the secondary battery further includes a solid electrolyte within the enclosure.

[0320] Embodiment 46. 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.

[0321] Embodiment 47. The secondary battery contains 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:

[0322] Embodiment 48. 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.

[0323] Embodiment 49. 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.

[0324] 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 oxide-based electrolytes.

[0325] Embodiment 51. The secondary battery includes a lithium lanthanum titanate (Li 0.34 La0.56 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 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).

[0326] Embodiment 52. 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.

[0327] Embodiment 53. 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 comprising an intercalation-type chemical cathode material.

[0328] Embodiment 54. 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.

[0329] Embodiment 55. 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.

[0330] Embodiment 56: A secondary battery assembly as described in any one of the preceding embodiments, comprising 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, wherein each unit cell of the population of unit cells includes an electrode structure, a separator structure, and a counter electrode structure.

[0331] Embodiment 57: A secondary battery assembly as described in embodiment 56, wherein the electrode structure is one of a positive electrode and a negative electrode, 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.

[0332] Embodiment 58: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.2:1.

[0333] Embodiment 59: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.3:1.

[0334] Embodiment 60: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 1.5:1.

[0335] Embodiment 61: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 2:1.

[0336] Embodiment 62: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 3:1.

[0337] Embodiment 63: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 4:1.

[0338] Embodiment 64: A secondary battery assembly as described in embodiment 57, wherein the ratio of negative electrode coulombic capacity to positive electrode coulombic capacity is at least 5:1.

[0339] Embodiment 65: A secondary battery assembly according to any one of the preceding embodiments, comprising a lithium-containing secondary battery and an auxiliary electrode.

[0340] Embodiment 66: The secondary battery assembly of embodiment 65, wherein the auxiliary electrode includes 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 the lithium-containing secondary battery, and a second separator layer comprising an ion-permeable material and in contact with the carrier ion supply layer.

[0341] Embodiment 67: A secondary battery assembly as described in embodiment 66, 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 region and the second region, wherein one of the carrier ion supply layers is disposed within the first region and another of the carrier ion supply layers is disposed within the second region.

[0342] Embodiment 68: A secondary battery assembly as described in embodiment 67, wherein the second separator layer is in contact with the third region of the second surface of the conductive layer.

[0343] Embodiment 69: A secondary battery assembly as described in embodiment 67 or 68, wherein the first region, the second region, and the third region are disposed along the length of the conductive layer.

[0344] Embodiment 70: A secondary battery assembly described in any one of embodiments 66 to 69, wherein the first separator layer and the second separator layer are mechanically bonded around at least a portion of the first separator layer and the second separator layer.

[0345] Embodiment 71: A secondary battery assembly described in any one of embodiments 66 to 69, 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.

[0346] Embodiment 72: A secondary battery assembly as described in embodiment 71, wherein the continuous separator material has a thickness in the range of about 0.01 millimeters to about 1 millimeter.

[0347] Embodiment 73: A secondary battery assembly as described in embodiment 72, wherein the thickness of the continuous separator material is about 0.025 millimeters.

[0348] Embodiment 74: A secondary battery assembly described in any one of embodiments 66 to 73, wherein the first separator layer and the second separator layer have a thickness ranging from about 0.01 millimeters to about 1 millimeter.

[0349] Embodiment 75: A secondary battery assembly described in any one of embodiments 66 to 74, wherein the second separator layer has a thickness of about 0.025 millimeters.

[0350] Embodiment 76: A secondary battery assembly described in any one of embodiments 66 to 75, wherein the conductive layer includes one of copper and aluminum, or an alloy of copper and aluminum.

[0351] Embodiment 77: A secondary battery assembly described in any one of embodiments 66 to 76, wherein the conductive layer comprises copper.

[0352] Embodiment 78: A secondary battery assembly described in any one of embodiments 66 to 77, wherein the thickness of the conductive layer has a value in the range of about 0.01 millimeters to about 1 millimeter.

[0353] Embodiment 79: A secondary battery assembly described in any one of embodiments 66 to 78, wherein the conductive layer has a thickness of about 0.1 millimeters.

[0354] Embodiment 80: A secondary battery assembly described in any one of embodiments 66 to 79, wherein the carrier ion supply layer has a thickness in the range of about 0.05 millimeters to about 1 millimeter.

[0355] Embodiment 81: A secondary battery assembly described in any one of embodiments 66 to 80, wherein the carrier ion supply layer has a thickness of about 0.15 millimeters.

[0356] Embodiment 82: A secondary battery assembly described in any one of embodiments 66 to 81, wherein the carrier ion supply layer provides a source of lithium ions.

[0357] Embodiment 83: A secondary battery assembly described in any one of embodiments 66 to 82, wherein the carrier ion supply layer is cold welded to the second surface of the conductive layer.

[0358] Embodiment 84: A secondary battery assembly described in any one of embodiments 66 to 83, wherein the auxiliary electrode includes a conductive tab coupled to the second surface of the conductive layer, the conductive tab comprising a conductive material.

[0359] Embodiment 85: A secondary battery assembly as described in embodiment 84, 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.

[0360] Embodiment 86: A secondary battery assembly as described in embodiment 84 or 85, wherein the conductive tab comprises one of nickel, copper, aluminum, or an alloy of copper, nickel and aluminum.

[0361] Embodiment 87: A secondary battery assembly as described in embodiment 84 or 85, wherein the conductive tab comprises nickel.

[0362] 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 device that forms a battery unit, The auxiliary electrode is operably coupled to the battery unit and configured to allow the flow of carrier ions from the auxiliary electrode to the unit cell in order to form a unit cell of the battery unit, wherein the carrier ions are involved in the electrolysis process within the unit cell, and the coupling between the auxiliary electrode and the battery unit is made by at least a portion of coupling the auxiliary electrode to at least one face of the battery unit, An electrical connector for connecting the auxiliary electrode to the unit cell A device equipped with the following features.

2. The auxiliary electrode is configured to be able to be disconnected from the unit cell. The device according to claim 1.

3. The device is configured to be operably coupled to a compression fixture for the flow of carrier ions from the auxiliary electrode to the unit cell of the battery unit. The device according to claim 1.

4. The auxiliary electrode is configured to be bonded to at least one surface of the unit cell. The device according to claim 1.

5. The at least one surface is the main surface of the battery unit. The device according to claim 4.

6. The auxiliary electrodes are configured to be simultaneously bonded to opposing surfaces of the unit cell. The device according to claim 1.

7. The auxiliary electrode is coupled to the unit cell at least partially by operably coupling it to a constraint portion coupled to the unit cell, the constraint portion being configured to facilitate the flow of electrolyte passing through it and thereby enable the flow of carrier ions. The device according to claim 1.

8. The restricting portion has perforations configured to facilitate the flow of electrolytes passing through it, thereby enabling the flow of carrier ions. The device according to claim 7.

9. The constraint portion includes metal, polymer, ceramic, fiber, composite material, or any combination thereof. The device according to claim 7.

10. The unit cell comprises silicon, silicon composites, silicon blends, silicon oxide, porous silicon, silicon alloys, or mixtures thereof. The device according to claim 1.

11. The battery unit comprises unit cells similar to the unit cell, and the auxiliary electrode is configured to be coupled to at least one side of the battery unit. The device according to claim 1.

12. The battery unit comprises an electrolyte configured to transport the carrier ions from the auxiliary electrode to the unit cell, wherein the electrolyte is a liquid electrolyte, and the formation of the battery unit includes forming a solid electrolyte interface within the unit cell in at least part of the form by the carrier ions. The device according to claim 1.

13. The battery unit comprises unit cells similar to the unit cell, the unit cells are stacked along an axis, and the auxiliary electrodes are coupled to at least one side of the battery unit and configured to be parallel to the axis. The device according to claim 1.

14. The aforementioned battery unit is a secondary battery. The device according to claim 1.

15. The unit cell comprises an electrode and a counter electrode, each of the electrode and / or the counter electrode having a length, width, and height, the height, length, and width aligned with the axes of a Cartesian coordinate system, the length ranging from approximately 5 millimeters (mm) to approximately 500 mm, the width ranging from approximately 0.01 mm to approximately 2.5 mm, and the height ranging from approximately 0.05 mm to approximately 25 mm, and the battery unit comprises one to 200 or more of the unit cells. The device according to claim 1.

16. The unit cell comprises an electrode separated from a counter electrode by a separator, each of the electrode and / or the counter electrode having a length, width, and height, the height, length, and width aligned with the axes of a Cartesian coordinate system, the ratio of the length to the width and height being at least 5:1, and the ratio of the height to the width being at least 0.4:1, the separator may have a thickness of at least about 4 micrometers to about 50 micrometers, and the battery unit comprises one to 200 or more of the unit cells. The device according to claim 1.

17. The unit cell comprises an anode separated from the cathode, and the anode has a concentration of 0.1 milligrams per square centimeter (mg / cm³). ２ ) 5 mg / cm ２ Having a filling amount, The device according to claim 1.

18. (a) To manufacture any device from claim 1 to 17, (b) Using the device to buffer the battery unit for the formation of the battery unit, (c) Controlling the device during the formation of the battery unit, or (d) Any combination of (a), (b), and (c) A method for forming a battery unit, including the following:

19. A battery unit forming apparatus comprising at least one controller operably coupled to any device of claims 1 to 17, wherein the at least one controller is configured to control the battery unit, and the at least one controller is coupled to a power supply.

20. A device that introduces carrier ions into a unit cell, A device comprising an enclosure that seals an auxiliary electrode and a battery unit from the external environment to the enclosure, the enclosure enabling electrical coupling between the auxiliary electrode and the battery unit in the external environment, the auxiliary electrode being operably coupled to the battery unit and configured to enable the flow of carrier ions from the auxiliary electrode to the unit cell of the battery unit, the carrier ions participating in the electrolysis process within the unit cell.

21. A device that introduces carrier ions into a battery, (I) A compression fixture comprising a base and (II) a compression plate set, The aforementioned compression plate set is (a) Fixed compression plate and (b) A movable compression plate, which is movable relative to the fixed compression plate, and which defines a receptacle between the movable compression plate and the fixed compression plate for receiving a battery unit operably coupled to an auxiliary electrode and enabling the flow of carrier ions from the auxiliary electrode to the battery unit, (c) at least one mechanism operably coupled to the movable compression plate, the at least one mechanism configured to bias the movable compression plate toward the fixed compression plate such that a compressive force is applied when the battery unit and the auxiliary electrode are positioned within the receptacle, and Includes, The device is configured to enable an electrical connection between the auxiliary electrode and the battery unit, thereby enabling the flow of carrier ions into the battery unit.

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