Restraint in longitudinal direction for energy storage device

Abstract

To provide a secondary battery having improved reliability and cycle life.SOLUTION: A secondary battery that is airtightly sealed so as to be cycled between a charge state and a discharge state includes an enclosure for airtightly sealing a content of the secondary battery, an electrode assembly and a non-aqueous liquid electrolyte in the enclosure, and a restraint in the enclosure for keeping a pressure to the electrode assembly, when the secondary battery is cycled between the charge state and the discharge state, wherein the electrode assembly includes an assembly of electrode structures, an assembly of counter electrode structures, and an electric insulative separator material between members of the electrode assembly and the counter electrode assembly, the electrode assembly surrounds first and second longitudinal end faces which are separated from one another and face each other in a longitudinal axis, and an outside surface which surrounds the longitudinal axis and connects the first and second longitudinal end faces.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure generally relates to structures for use in energy storage devices, energy storage devices incorporating the structures, and methods of making the structures and energy devices. [Background technology]

[0002] A rocking chair or insertion secondary battery is a type of energy storage device in which carrier ions, such as lithium, sodium, potassium, calcium, magnesium, or aluminum ions, move between a positive electrode and a negative electrode through an electrolyte. A secondary battery includes a single battery cell or two or more battery cells electrically coupled to form a battery, each battery cell including a positive electrode, a negative electrode, a microporous separator, and an electrolyte.

[0003] In a rocking chair battery cell, both the positive and negative electrode structures contain materials through which carrier ions can move in and out. When the cell is discharged, carrier ions are extracted from the negative electrode and inserted into the positive electrode. When the cell is charged, the reverse process occurs; carrier ions are extracted from the positive electrode and inserted into the negative electrode.

[0004] FIG. 1 shows a cross-sectional view of an electrochemical stack of an existing energy storage device, such as a non-aqueous secondary battery. The electrochemical stack 1 includes, in a stacked configuration, a positive electrode assembly 3, a positive electrode active material layer 5, a microporous separator 7, a negative electrode active material layer 9, and a negative electrode assembly 11. Each of the layers has a height measured in the electrode stacking direction (i.e., in the direction from the positive electrode assembly 3 to the negative electrode assembly 11 as shown in FIG. 1) that is significantly smaller (e.g., at least 10 times smaller) than the length and width of each of the layers measured in directions perpendicular to each other and perpendicular to the electrode stacking direction, respectively. Now referring to FIG. 2, a roll 13 (sometimes referred to as a "jelly roll") having a top 15 and a bottom 17 is formed by rolling the electrochemical stack around a central axis 19, after which the roll 13 is packed into a can (not shown) and filled with a non-aqueous electrolyte to assemble a secondary battery. As shown in FIG. 2, the electrode stacking direction of the layers is perpendicular to the central axis 19.

[0005] Existing energy storage devices, such as batteries, fuel cells, and electrochemical capacitors, typically have a two-dimensional thin-layer architecture (e.g., planar or spiral-wound stacks) as shown in Figures 1 and 2, where the surface area of ​​each individual stack is roughly equal to the geometric footprint (ignoring porosity and surface roughness). Three-dimensional batteries have been proposed in the literature as a way to improve battery capacity and active material utilization. It has been proposed that three-dimensional architectures can be used to provide higher surface areas and higher energy compared to two-dimensional thin-layer battery architectures. There are advantages to creating three-dimensional energy storage devices due to the increased amount of energy that can be obtained from a small geometric area. See, for example, WO2008 / 089110 by Rust et al. and "Three-dimensional battery architectures" by Long et al., Chemical Reviews, (2004), 104, 4463-4492.

[0006] Conventional wound batteries (see, for example, U.S. Pat. Nos. 6,090,505 and 6,235,427 and FIG. 2) typically have the electrode materials (active material, binder, conductive aids) coated onto a single foil and compressed prior to cell assembly. The foil on which the electrodes are coated is typically part of the current collection path. In a single jelly roll battery, such as an 18650 or prismatic cell, the current collector foil is ultrasonically welded to an electrode bus, tab, tag, etc., that carries the current from the active material through the current collector foil and tab to the exterior of the battery. Depending on the design, there may be tabs in multiple locations along the single jelly roll, or there may be tabs along one location on one or both ends of the current collector foil. Conventional stacked battery pouch cells have multiple plates (or foils) of active material gathered in sequence and welded to a tab, with an area on top of each individual foil. The plates then carry the electrical current to the exterior of the battery pouch (see, for example, US Patent Application Publication No. 2005 / 0008939). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2008 / 089110 [Patent Document 2] U.S. Patent No. 6,090,505 [Patent Document 3] U.S. Patent No. 6,235,427 [Patent Document 4] US Patent Application Publication No. 2005 / 0008939 [Non-patent literature]

[0008] [Non-Patent Document 1] Long et al., “Three-dimensional battery architectures,” Chemical Reviews, (2004), 104, 4463-4492 Summary of the Invention [Problem to be solved by the invention]

[0009] However, one of the challenges associated with secondary batteries is their reliability and cycle life. For example, the electrode structure of a lithium-ion battery tends to expand (swell) and contract when the battery is repeatedly charged and discharged, which can lead to electrical shorts and equipment failure. [Means for solving the problem]

[0010] Among the various aspects of the present disclosure, three-dimensional structures are provided for use in energy storage devices, such as batteries, fuel cells, and electrochemical capacitors. Advantageously, and according to one aspect of the present disclosure, the ratio of electrode active material to other components of the energy storage device (i.e., components of the non-active material of the energy storage device) can be increased. As a result, energy storage devices including the three-dimensional structures of the present disclosure can have higher energy density. They can also provide higher energy recovery rates for a given amount of energy stored than two-dimensional energy storage devices, for example, by minimizing or reducing the transport distances for electron and ion transfer between the positive and negative electrodes. These devices may be more suitable for miniaturization and for applications where the geometric area available for the device is limited and / or the energy density requirements are higher than can be achieved with thin-layer devices.

[0011] Briefly, therefore, according to one aspect of the disclosure, there is provided an energy storage device for cycling between a charged state and a discharged state. The energy storage device includes an enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the enclosure, and a restraint that maintains pressure on the electrode assembly as the energy storage device cycles between the charged state and the discharged state. The electrode assembly includes an assembly of electrode structures, an assembly of counter electrode structures, and an electrically insulating microporous separator material between the members of the electrode assembly and the counter electrode assembly. The electrode assembly includes opposing first and second longitudinal end faces separated along a longitudinal axis, and an exterior surface that surrounds the longitudinal axis and connects the first and second longitudinal end faces, the combined surface area of ​​the first and second longitudinal end faces being less than 33% of the combined surface area of ​​the exterior surface and the first and second longitudinal end faces. The members of the electrode assembly and the members of the counter electrode assembly are alternately arranged in a stacking direction parallel to the longitudinal axis within the electrode assembly. The constraint has first and second compression members connected by at least one tension member that pulls the compression members toward each other, and the constraint maintains a pressure on the electrode assembly in a stack direction that exceeds a pressure maintained on the electrode assembly in each of two directions that are perpendicular to each other and perpendicular to the electrode stack direction.

[0012] According to yet another aspect of the present disclosure, a secondary battery for cycling between a charged state and a discharged state is provided, the secondary battery having a battery enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the battery enclosure, and a restraint for maintaining pressure on the electrode assembly as the secondary battery cycles between a charged state and a discharged state. The electrode assembly has an assembly of electrode structures, an assembly of counter electrode structures, and an electrically insulating microporous separator material between the members of the electrode assembly and the counter electrode assembly. The electrode assembly has opposing first and second longitudinal end faces separated along a longitudinal axis, and an exterior surface surrounding the longitudinal axis and connecting the first and second longitudinal end faces, the surface area of ​​the first and second longitudinal end faces being less than 33% of the surface area of ​​the electrode assembly. The members of the electrode assembly and the members of the counter electrode assembly are alternately arranged in a stack direction parallel to the longitudinal axis within the electrode assembly. The projections of the electrode assembly and counter-electrode assembly members onto the first longitudinal surface enclose a first projected area and the projections of the electrode assembly and counter-electrode assembly members onto the second longitudinal surface enclose a second projected area, the constraint has first and second compression members overlying the first and second projected areas respectively, the compression members overlying outer surfaces of the electrode assemblies and connected by tension members pulling the compression members towards each other, the constraint maintaining a pressure on the electrode assembly in the stack direction that exceeds pressures maintained on the electrode assembly in each of two directions orthogonal to each other and orthogonal to the electrode stack direction.

[0013] Other objects and features will be in part apparent and in part pointed out hereinafter. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a cell of an electrochemical stack of a prior art two-dimensional energy storage device, such as a lithium-ion battery. [Diagram 2] FIG. 1 is a cross-sectional view of a cell of a wound electrochemical stack of a prior art two-dimensional energy storage device, such as a lithium ion battery. [Figure 3A]FIG. 2 is a schematic diagram of one embodiment of an electrode assembly of the present disclosure having a triangular prism shape. [Figure 3B] FIG. 2 is a schematic diagram of one embodiment of an electrode assembly of the present disclosure having a parallel pipe geometry. [Figure 3C] FIG. 2 is a schematic diagram of one embodiment of an electrode assembly of the present disclosure having a rectangular prism shape. [Figure 3D] FIG. 2 is a schematic diagram of one embodiment of an electrode assembly of the present disclosure having a pentagonal prism shape. [Figure 3E] FIG. 2 is a schematic diagram of one embodiment of an electrode assembly of the present disclosure having a hexagonal prism shape. [Figure 4] FIG. 1 is a schematic exploded view of one embodiment of a secondary battery of the present disclosure. [Figure 5A] 5 is a schematic end view of one end of the electrode assembly of the secondary battery of FIG. 4. [Figure 5B] 5B is a schematic end view of opposing ends of the electrode assembly of FIG. 5A. [Figure 5C] FIG. 5B is a schematic top view of the outer surface of the electrode assembly of FIG. 5A. [Figure 5D] FIG. 5B is a schematic bottom view of the opposite exterior surface of the electrode assembly of FIG. 5A. [Figure 6A] FIG. 5 is a schematic perspective view of the secondary battery of FIG. 4 in a restrained state. [Figure 6B] 1 illustrates one embodiment of a cross section of an electrode assembly having a constraint with an internal compression member. [Figure 6C] 1 illustrates one embodiment of a cross section of an electrode assembly having a constraint with multiple internal compression members. [Figure 7] FIG. 2 is a schematic exploded view of another embodiment of a secondary battery of the present disclosure. [Figure 8] FIG. 2 is a schematic diagram of another embodiment of a deployed restraint for an electrode assembly of a secondary battery of the present disclosure. [Figure 9] FIG. 9 is a schematic diagram of the constraint of FIG. 8 after it has been folded. [Figure 10A] FIG. 2 is a schematic diagram of another embodiment of a restraint and electrode assembly of a secondary battery of the present disclosure. [Figure 10B]FIG. 10B is an enlarged view of the restraint and electrode assembly of FIG. 10A. [Figure 11A] FIG. 2 is a schematic diagram of another embodiment of a constraint for an electrode assembly of a secondary battery of the present disclosure. [Figure 11B] FIG. 11B is an enlarged view of the constraint of FIG. 11A. [Figure 12A] FIG. 1 is a perspective view of one embodiment of an electrode assembly of a secondary battery of the present disclosure, with a portion removed to show the internal structure. [Figure 12B] FIG. 12B is an end view of one end of the electrode assembly of FIG. 12A. [Figure 12C] FIG. 12B is an end view of opposite ends of the electrode assembly of FIG. 12A. [Figure 13] FIG. 2 is a perspective view of another embodiment of a secondary battery of the present disclosure with a portion removed to show the internal structure. [Figure 14] FIG. 2 is a perspective view of another embodiment of a secondary battery of the present disclosure with a portion removed to show the internal structure. [Figure 15] FIG. 2 is a perspective view of another embodiment of a secondary battery of the present disclosure with a portion removed to show the internal structure. [Figure 16] 1 is a cross-sectional view of another embodiment of a restraint and electrode assembly of the present disclosure.

[0015] Corresponding reference characters indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] definition

[0017] As used herein, singular references refer to plural referents unless the context clearly dictates otherwise. For example, in one instance, reference to an "electrode" includes both a singular electrode and a plurality of similar electrodes.

[0018] As used herein, "about" and "approximately" refer to ±10%, 5%, or 1% of the stated value. For example, in one example, about 250 μm includes 225 μm to 275 μm. As a further example, in one example, about 1000 μm includes 900 μm to 1100 μm. Unless otherwise indicated, all numbers expressing quantities (e.g., measurements, etc.) and the like used in the specification and claims should be understood to be modified in all instances by "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations. Each numerical parameter should be construed at least in light of the number of significant digits accounted for and by applying ordinary rounding techniques.

[0019] As used herein in the context of describing the state of a secondary battery, a "state of charge" refers to a state in which a secondary battery is charged to at least 75% of its rated capacity. For example, a battery can 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 (e.g., 100% of its rated capacity).

[0020] As used herein in the context of describing the state of a secondary battery, a "discharged state" refers to a state in which a secondary battery has been discharged to less than 25% of its rated capacity. For example, a battery can be discharged to less than 20% of its rated capacity (e.g., less than 10% of its rated capacity), or even less than 5% of its rated capacity (e.g., 0% of its rated capacity).

[0021] As used herein in the context of describing cycling of a secondary battery between a charge state and a discharge state, "cycling" refers to charging and / or discharging the battery to change the battery from a first state, either a charge state or a discharge state, to a second state opposite the first state (i.e., the charge state if the first state is a discharge state, or the discharge state if the first state is a charge state) in a cycle, and then returning the battery to the first state to complete the cycle. For example, a single cycle of a secondary battery between a charge state and a discharge state can include charging from the discharge state to the charge state, and then discharging to the discharge state to complete the cycle. A single cycle can also include discharging the battery from the charge state to the discharge state, and then charging to the charge state to complete the cycle.

[0022] As referred to herein in relation to an electrode assembly, the "ferret diameter" is defined as the distance between two planes that constrain the electrode assembly measured in a direction perpendicular to the two parallel planes.

[0023] As used herein, "longitudinal axis", "horizontal axis" and "vertical axis" refer to mutually orthogonal axes (i.e., each perpendicular to the other). For example, as used herein, "longitudinal axis", "horizontal axis" and "vertical axis" are analogous to a Cartesian coordinate system used to define three-dimensional shapes or orientations. Thus, the description of the elements of the subject matter of the present invention is not limited to the particular coordinate axis or axes used to describe the three-dimensional orientation of the elements. In other words, the coordinate axes can be interchangeable when referring to the three-dimensional shapes of the subject matter of the present invention.

[0024] As used herein, "longitudinal," "lateral," and "vertical" refer to mutually orthogonal directions (i.e., each is perpendicular to the other). For example, as used herein, "longitudinal," "lateral," and "vertical" may be approximately parallel to the longitudinal, lateral, and vertical axes, respectively, of a Cartesian coordinate system used to define three-dimensional shapes or orientations.

[0025] As used herein in the context of describing cycling between a charge state and a discharge state of a secondary battery, "repeated cycles" refers to cycling from a discharge state to a charge state or from a charge state to a discharge state two or more times. The repeated cycles between the charge state and the discharge state can include cycling from the discharge state to the charge state at least twice (e.g., charging from the discharge state to the charge state, discharging back to the discharge state, charging again to the charge state, and finally discharging back to the discharge state). As yet another example, the at least two repeated cycles between the charge state and the discharge state can include discharging from the charge state to the discharge state, charging back to the charge state, discharging again to the discharge state, and finally charging back to the charge state. As a further example, the repeated cycles between the charge state and the discharge state can include at least five cycles from the discharge state to the charge state, and even at least ten cycles. As a further example, the repeated cycling between the charged and discharged states can include cycling from the discharged state to the charged state at least 25, 50, 100, 300, 500, or even 1000 times.

[0026] "Rated power output," as used herein in the context of describing a secondary battery, refers to the capacity of a secondary battery to supply current for a period of time, measured at standard temperature conditions (25°C). For example, rated power output may be measured in ampere-hours by determining the current output for a particular period of time, or by determining the time that current may be output for a particular current and taking the product of current and time. For example, for a battery rated at 20 ampere-hours, if the current is specified as 2 amperes for the rating, the battery may be understood to supply that current output for 10 hours, and conversely, if the time is specified as 10 hours for the rating, the battery may be understood to output 2 amperes for the 10 hours.

[0027] Detailed Description

[0028] Generally, the secondary battery of the present disclosure comprises a battery enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the battery enclosure, and a constraint that maintains pressure on the electrode assembly as the secondary battery cycles between a charged state and a discharged state. As previously mentioned, during formation of the secondary battery and / or subsequent cycling of the secondary battery between a charged state and a discharged state, the electrodes and / or counter electrodes in the electrode assembly may expand in the electrode and counter electrode stacking direction. Such expansion becomes a challenge when the electrode assembly includes dozens (or more) of stacked electrodes and counter electrodes. Advantageously, the constraint of the present disclosure maintains pressure on the electrode assembly that inhibits expansion of the electrode assembly (in the stacking direction) during formation of the battery and / or subsequent cycling of the battery between a charged state and a discharged state. Additionally, the constraint further inhibits buckling of the electrode assembly that could potentially result from differential pressure exerted by the constraint on different surfaces of the electrode assembly.

[0029] The constraints of the present disclosure may be embodied, for example, in any of the structures including the battery enclosure itself, structures external to the battery enclosure, structures within the battery enclosure, or a combination of the battery enclosure with structures within the battery enclosure and / or structures external to the battery enclosure. In one such embodiment, the battery enclosure is a part of the constraint, in other words, in this embodiment, the battery enclosure, either alone or in combination with one or more other structures (within the battery enclosure and / or external), exerts a pressure on the electrode structures in the electrode stack direction that is greater than the pressure on the electrode structures in directions perpendicular to each other and perpendicular to the electrode stack direction. In another embodiment, the constraint does not include the battery enclosure and one or more separate structures (within the battery enclosure and / or external) other than the battery enclosure that exert a pressure on the electrode structures in the electrode stack direction that is greater than the pressure on the electrode structures in directions perpendicular to each other and perpendicular to the electrode stack direction.

[0030] In one exemplary embodiment, the restraint includes one or more separate structures within the battery enclosure that exert a pressure on the electrode structures in the electrode stack direction that exceeds the pressure exerted on the electrode structures in two directions that are perpendicular to the electrode stack direction and perpendicular to each other.

[0031] In one exemplary embodiment, a constraint is present within the battery enclosure and exerts a pressure on the electrode structure in the electrode stack direction that exceeds the pressure exerted on the electrode structure in two directions that are perpendicular to the electrode stack direction and perpendicular to each other.

[0032] In one exemplary embodiment, the restraint includes one or more separate structures external to the battery enclosure and one or more separate structures inside the battery enclosure that in combination exert a pressure on the electrode structures in the electrode stack direction that exceeds the pressure on the electrode structures in two directions perpendicular to the electrode stack direction and perpendicular to each other.

[0033] Regardless of the location of the restraint (e.g., inside or outside the battery enclosure and / or contained within the enclosure), the restraint and battery enclosure preferably combine to occupy no more than 75% of the volume enclosed by the exterior surface of the battery enclosure (i.e., the displaced volume of the battery). For example, in one such embodiment, the restraint and battery enclosure combine to occupy no more than 60% of the volume enclosed by the exterior surface of the battery enclosure. By way of further example, in one such embodiment, the restraint and battery enclosure combine to occupy no more than 45% of the volume enclosed by the exterior surface of the battery enclosure. By way of further example, in one such embodiment, the restraint and battery enclosure combine to occupy no more than 30% of the volume enclosed by the exterior surface of the battery enclosure. By way of further example, in one such embodiment, the restraint and battery enclosure combine to occupy no more than 20% of the volume enclosed by the exterior surface of the battery enclosure.

[0034] An electrode assembly of the present disclosure generally comprises two opposing longitudinal end faces (separated along a longitudinal axis of the electrode assembly) and an outer surface (circumscribing the longitudinal axis) extending between the two opposing longitudinal end faces. In general, the longitudinal end faces may be planar or non-planar. For example, in one embodiment, the opposing longitudinal end faces are convex. As a further example, in one embodiment, the opposing longitudinal end faces are concave. As a further example, in one embodiment, the opposing longitudinal end faces are substantially planar.

[0035] The opposing longitudinal end faces may also have any range of two-dimensional shapes when projected onto a plane. For example, the longitudinal end faces may independently have a smoothly curved shape (e.g., circular, elliptical, hyperbolic, or parabolic), may independently include a series of lines and vertices (e.g., polygonal), or may independently include a smoothly curved shape and include one or more lines and vertices. Similarly, the outer surface of the electrode assembly may be smoothly curved (e.g., the electrode assembly has a circular, elliptical, hyperbolic, or parabolic cross-sectional shape), or the outer surface may include two or more faces connected at vertices (e.g., the electrode assembly may have a polygonal cross-section). For example, in one embodiment, the electrode assembly has a cylindrical, elliptical cylindrical, parabolic cylindrical, or hyperbolic cylindrical shape. As a further example, in one such embodiment, the electrode assembly may have opposing longitudinal end faces of the same size and shape and an outer surface of a parallelogram (i.e., the face extending between the opposing longitudinal end faces). By way of further example, in one such embodiment, the electrode assembly has a shape corresponding to a triangular prism, the electrode assembly having two opposing triangular longitudinal end faces and an outer surface consisting of three parallelograms (e.g., rectangular) extending between the two longitudinal end faces. By way of further example, in one such embodiment, the electrode assembly has a shape corresponding to a rectangular prism, the electrode assembly having two opposing rectangular longitudinal end faces and an outer surface including four parallelogram (e.g., rectangular) faces. By way of further example, in one such embodiment, the electrode assembly has a shape corresponding to a pentagonal prism, hexagonal prism, etc., the electrode assembly having two opposing longitudinal end faces, each pentagonal, hexagonal, etc., and an outer surface including five, six, etc. parallelogram (e.g., rectangular) faces.

[0036] 3A-3E, several exemplary geometric shapes are shown diagrammatically for the electrode assembly 120. In FIG. 3A, the electrode assembly 120 has a triangular prism shape having opposing first and second longitudinal end faces 122, 124 separated along a longitudinal axis A and an outer surface (not numbered) that connects the longitudinal end faces and includes three rectangular faces that surround the longitudinal axis A. In FIG. 3B, the electrode assembly 120 has a parallelepiped shape having opposing first and second parallelogram longitudinal end faces 122, 124 separated along a longitudinal axis A and an outer surface (not numbered) that connects the two longitudinal end faces and includes four parallelogram faces that surround the longitudinal axis A. In FIG. 3C, the electrode assembly 120 has a rectangular prism shape having opposing first and second rectangular longitudinal end faces 122, 124 separated along a longitudinal axis A and an outer surface (not numbered) that connects the two longitudinal end faces and includes four rectangular faces that surround the longitudinal axis A. In Figure 3D, the electrode assembly 120 has a pentagonal prism shape having first and second opposing pentagonal longitudinal end faces 122, 124 separated along a longitudinal axis A, and an outer surface (unnumbered) that connects the two longitudinal end faces and includes five rectangular faces circumscribing the longitudinal axis A. In Figure 3E, the electrode assembly 120 has a hexagonal prism shape having first and second opposing hexagonal longitudinal end faces 122, 124 separated along a longitudinal axis A, and an outer surface (unnumbered) that connects the two longitudinal end faces and includes six rectangular faces circumscribing the longitudinal axis A.

[0037] Regardless of the overall geometric shape of the electrode assembly, the opposing first and second longitudinal end faces of the electrode assembly have a combined surface area that is less than 50% of the total surface area of ​​the electrode assembly (i.e., the total surface area is the sum of the surface areas of the first and second longitudinal end faces and the surface area of ​​the outer surface of the electrode assembly). For example, the first and second opposing longitudinal end faces 122, 124 of each electrode assembly 120 of Figures 3A-3E have a combined surface area (i.e., the sum of the surface areas of the first and second longitudinal end faces) that is less than 50% of the total surface area of ​​a triangular prism (Figure 3A), parallelepiped (Figure 3B), rectangular prism (Figure 3C), pentagonal prism (Figure 3D), or hexagonal prism (Figure 3E), respectively. For example, in one such embodiment, the opposing first and second longitudinal end faces of the electrode assembly have a surface area that is less than 33% of the total surface area of ​​the electrode assembly. By way of further example, in one such embodiment, the opposing first and second longitudinal end faces of the electrode assembly have a surface area that is less than 25% of the total surface of the electrode assembly. By way of further example, in one such embodiment, the opposing first and second longitudinal end faces of the electrode assembly have a surface area that is less than 20% of the total surface of the electrode assembly. By way of further example, in one such embodiment, the opposing first and second longitudinal end faces of the electrode assembly have a surface area that is less than 15% of the total surface of the electrode assembly. By way of further example, in one such embodiment, the opposing first and second longitudinal end faces of the electrode assembly have a surface area that is less than 10% of the total surface of the electrode assembly.

[0038] In some embodiments, the electrode assembly is a rectangular prism, the first and second opposing longitudinal end faces having a combined surface area (i.e., the sum of the surface areas of the two opposing rectangular outer faces connecting the opposing longitudinal end faces) that is less than the combined surface area of ​​at least two opposing faces of the outer face. In some embodiments, the electrode assembly is a rectangular prism, the rectangular prism having first and second opposing longitudinal end faces and an outer face including two pairs of opposing surfaces (faces), the two opposing longitudinal end faces having a combined surface area that is less than the combined surface area of ​​at least one pair of the two pairs of opposing faces included in the outer face. In some embodiments, the electrode assembly is a rectangular prism, the rectangular prism having two opposing first and second longitudinal end faces and an outer face including two pairs of opposing surfaces (faces), the two opposing longitudinal end faces having a combined surface area that is less than the combined surface area of ​​each pair of the two pairs of opposing faces included in the outer face.

[0039] Typically, the electrode assembly includes an electrode assembly and a counter-electrode assembly stacked in a direction (i.e., electrode stacking direction) that is aligned with the longitudinal axis of the electrode assembly (see, e.g., FIGS. 3A-3E). In other words, the electrodes and counter-electrodes are stacked in a direction extending from a first opposing longitudinal end face to a second opposing longitudinal end face of the electrode assembly. In one embodiment, the members of the electrode assembly and / or the members of the counter-electrode assembly are laminar in nature (see, e.g., FIGS. 1 and 2). In another embodiment, the members of the electrode assembly and / or the members of the counter-electrode assembly are non-laminar in nature, in other words, in one embodiment, the members of the electrode assembly and / or the members of the counter-electrode assembly extend sufficiently from a virtual backplane (e.g., a plane substantially aligned with the surface of the electrode assembly) to have a surface area (ignoring porosity) that is greater than twice the geometric footprint (i.e., projection) of the members within the backplane. In certain embodiments, the ratio of the surface area of ​​a non-laminar (i.e., three-dimensional) electrode and / or counter-electrode structure to its non-geometric footprint in the virtual backplane can be at least about 5, at least about 10, at least about 50, at least about 100, or even at least about 500. Generally, however, this ratio is from about 2 to about 1000. In one such embodiment, the members of the electrode assembly are non-laminar in nature. As a further example, in one such embodiment, the members of the counter-electrode assembly are non-laminar in nature. As a further example, in one such embodiment, the members of the electrode assembly and the members of the counter-electrode assembly are non-laminar in nature.

[0040] During formation and / or cycling of a secondary battery incorporating the electrode assembly, expansion of the electrode assembly in a longitudinal direction (e.g., a direction parallel to the longitudinal axis A in each of FIGS. 3A-3E) can be constrained by a constraint of the present disclosure. In general, the constraint comprises a compression member (adapted to overlie the first and second projected regions, respectively) connected by a tension member (adapted to overlie the outer surface of the electrode assembly). The tension member pulls the compression members toward each other, thereby applying a compressive force to the opposing first and second longitudinal end faces of the electrode assembly, thereby constraining expansion of the electrode assembly in the longitudinal direction (which coincides with the electrode stacking direction as further described herein). Additionally, after the battery is formed, the constraint exerts a pressure on the electrode assembly in the longitudinal direction (i.e., the electrode stacking direction) that exceeds the pressure maintained on the electrode assembly in each of two directions that are mutually orthogonal and orthogonal to the longitudinal direction.

[0041] 4, there can be seen an exploded view of one embodiment of a secondary battery of the present disclosure, generally designated 100. The secondary battery includes a battery enclosure 102 and a set 110 of electrode assemblies 120 within the battery enclosure 102, each of the electrode assemblies having a first longitudinal end face 122, an opposing second longitudinal end face 124 (separated from the first longitudinal end face 122 along a longitudinal axis (not shown) parallel to the "Y-axis" of a virtual Cartesian coordinate system of FIG. 4), and outer surfaces including outer surfaces 123, 125, 126, 127 (see FIG. 12A). Each electrode assembly includes a collection of electrode structures and a collection of counter-electrode structures stacked on top of each other within each of the electrode assemblies (see, e.g., FIG. 12A) in an electrode stacking direction D, in other words, the collection of electrode structures and counter-electrode structures are arranged in an alternating series of electrodes and counter-electrodes progressing in the direction D between a first longitudinal end face 122 and a second longitudinal end face 124 (see, e.g., FIG. 12A. As shown in FIG. 4, the electrode stacking direction D is parallel to the Y-axis of the imaginary Cartesian coordinate system of FIG. 4). Also, the stacking direction D of the electrodes within an individual electrode assembly 120 is orthogonal to the stacking direction of the collection of electrode assemblies 120 within the set 110 (i.e., the stacking direction of the electrode assemblies). In other words, the electrode assemblies are inter-arranged in a direction within the set 110 that is perpendicular to the electrode stacking direction D within each individual electrode assembly (e.g., the stacking direction of the electrode assemblies is in a direction corresponding to the Z-axis of a virtual Cartesian coordinate system, while the electrode stacking direction D within each individual electrode assembly is in a direction corresponding to the Y-axis of the virtual Cartesian coordinate system).

[0042] Tabs 141, 142 protrude from the battery enclosure to provide electrical connection between the electrode assemblies of set 110 and an energy supplying or consuming device (not shown). More specifically, in this embodiment, tab 141 is electrically connected (e.g., using a conductive adhesive) to tab extension 143, which is electrically connected to an electrode included in each of the electrode assemblies 120. Similarly, tab 142 is electrically connected (e.g., using a conductive adhesive) to tab extension 144, which is electrically connected to a counter electrode included in each of the electrode assemblies 120.

[0043] Each electrode assembly 120 of the embodiment shown in Figure 4 has an associated constraint 130 for constraining expansion in the longitudinal direction (i.e., electrode stacking direction D). Each constraint 130 includes a compression member 132, 134 (see Figures 5A and 5B) overlying the first and second longitudinal end faces 122, 124, respectively, and a tension member 133, 135 (see Figures 5C and 5D) overlying the outer surface 123, 125, respectively. The tension members 133, 135 pull the compression members 132, 134 toward each other, and the compression members 132, 134 apply a compressive force to the opposing first and second longitudinal end faces 122, 124. As a result, expansion of the electrode assembly in the longitudinal direction is constrained during formation of the battery and / or cycling of the battery between charge and discharge states. The constraints 130 also exert a pressure on the electrode assembly in a longitudinal direction (i.e., electrode stack direction D) that exceeds the pressure maintained on the electrode assembly in either of two mutually orthogonal directions and orthogonal to the longitudinal direction. (As shown, the longitudinal direction corresponds to the direction of the "Y" axis, and the two mutually orthogonal directions and orthogonal to the longitudinal direction correspond to the directions of the X and Z axes, respectively, of a virtual Cartesian coordinate system shown.)

[0044] 5A, 5B, 5C and 5D, each electrode assembly 120 in the embodiment of FIG. 4 has a geometric shape corresponding to that of a rectangular prism having first and second longitudinal end faces 122, 124 having dimensions X1×Z1, outer side faces 123, 125 having dimensions X1×Y1, and outer side faces 126, 127 having dimensions Y1×Z1 (where X1, Y1 and Z1 are dimensions measured in directions corresponding to the X, Y and Z axes, respectively, of a Cartesian coordinate system). Thus, the first and second longitudinal end faces 122, 124 have a surface area corresponding to the multiplication product of X1 and Z1, the outer side faces 123, 125 each have a surface area corresponding to the multiplication product of X1 and Y1, and the outer side faces 126, 127 each have a surface area corresponding to the multiplication product of Y1 and Z1. According to one aspect of the present disclosure, the sum of the surface areas of the first and second longitudinal end faces is less than 33% of the surface area of ​​the total surface of the electrode assembly, the electrode assembly is a rectangular prism, the combined surface area of ​​the first and second longitudinal end faces is equal to (X1×Z1)+(X1×Z1), and the surface area of ​​the outer surface is equal to (X1×Y1)+(X1×Y1)+(Y1×Z1)+(Y1×Z1). For example, in one such embodiment, the sum of the surface areas of the first and second longitudinal end faces is less than 25% of the surface area of ​​the total surface of the electrode assembly, the combined surface area of ​​the first and second longitudinal end faces is equal to (X1×Z1)+(X1×Z1), and the total surface area of ​​the electrode assembly is equal to (X1×Y1)+(X1×Y1)+(Y1×Z1)+(Y1×Z1)+(X1×Z1).

[0045] Each constraint 130 in this embodiment includes a compression member 132, 134 overlying the first and second longitudinal end faces 122, 124, respectively, and at least one tension member that pulls the compression members toward each other. For example, the constraints can include tension members 133, 135 overlying respective outer surfaces 123, 125 of the outer surfaces. In general, the compression members 132, 134 exert a pressure against the first and second longitudinal end faces 122, 124 (i.e., in the electrode stacking direction D) that exceeds the pressure maintained against the outer surfaces 123, 125 and outer surfaces 126, 127 of the electrode assembly (i.e., in each of two directions perpendicular to each other and perpendicular to the electrode stacking direction). For example, in one such embodiment, the constraint exerts a pressure on the first and second longitudinal end faces 122, 124 (i.e., in the electrode stacking direction D) that is at least three times greater than the pressure maintained on the electrode assembly in at least one of two directions orthogonal to the electrode stacking direction and mutually orthogonal, or even both. By way of further example, in one such embodiment, the constraint exerts a pressure on the first and second longitudinal end faces 122, 124 (i.e., in the electrode stacking direction D) that is at least four times greater than the pressure maintained on the electrode assembly in at least one of two directions orthogonal to the electrode stacking direction and mutually orthogonal, or even both. By way of further example, in one such embodiment, the constraint exerts a pressure on the first and second longitudinal end faces 122, 124 (i.e., in the electrode stacking direction D) that is at least five times greater than the pressure maintained on the electrode assembly in at least one of two directions orthogonal to the electrode stacking direction and mutually orthogonal, or even both.

[0046] 6A, in one embodiment, the constraint 130 may be derived from a sheet 107 having a length L1, a width W1, and a thickness t1. To form the constraint, the sheet 107 is simply wrapped around the electrode structure 120 (see FIGS. 4 and 5A-5D) and folded at fold line 113 to enclose the electrode structure. Edges 115, 117 overlap one another and are welded, glued, or otherwise secured to one another to form the constraint including compression members 132, 134 (compression member 134 including overlapping edges 115, 117 secured to one another) and tension members 133, 135. In this embodiment, the constraint has a volume corresponding to the displacement volume of the sheet 107 (i.e., the multiplication product of L1, W1, and t1).

[0047] The sheet 107 can comprise any of a wide range of compatible materials capable of applying the desired force to the electrode structure. In general, the constraint typically comprises a material that has an ultimate tensile strength of at least 10,000 psi (>70 MPa), is compatible with the battery electrolyte, does not significantly corrode at the floating or anode potential of the battery, and does not significantly react or lose mechanical strength at 45° C. For example, the constraint can comprise any of a wide range of metals, alloys, ceramics, glasses, plastics, or combinations thereof (i.e., composites). In one exemplary embodiment, the constraint comprises a metal (e.g., stainless steel (e.g., SS316, 440C, or 440C hard), aluminum (e.g., aluminum 7075-T6, hard H18), titanium (e.g., 6Al-4V), beryllium, beryllium copper (hard), copper (O2 free, hard), nickel). In general, however, if the constraint comprises a metal, it is generally preferred that it be incorporated in a manner that limits corrosion and limits the creation of an electrical short between the electrode and the counter-electrode. In another exemplary embodiment, the constraint comprises a ceramic (e.g., alumina (e.g., sintered or Coorstek AD96), zirconia (e.g., Coorstek YZTP), yttria stabilized zirconia (e.g., ENrG E-Strate®)). In another exemplary embodiment, the constraint comprises a glass (e.g., Schott D263 tempered glass). In another exemplary embodiment, the constraint comprises a plastic (e.g., 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), polyetheretherketone (PEEK) with 30% glass (e.g., Victrex 90HMF40 or Xycomp 1000-04), polyimide (e.g., Kapton®)).In another exemplary embodiment, the restraint comprises a composite material (e.g., E-glass standard Fabric / epoxy, 0°, E-glass UD / epoxy, 0°, Kevlar standard Fabric / epoxy, 0°, Kevlar UD / epoxy, 0°, Carbon standard Fabric / epoxy, 0°, Carbon UD / epoxy, 0°, Toyobo Zylon® HM fiber / epoxy). In another exemplary embodiment, the restraint comprises a fiber (e.g., Kevlar 49 aramid fiber, S-glass fiber, carbon fiber, Vectran UM LCP fiber, Dyneema, Zylon).

[0048] The thickness (t1) of the constraint depends on a range of factors including, for example, the material of construction of the constraint, the overall dimensions of the electrode assembly, and the composition of the anode and cathode of the battery. In some embodiments, for example, the constraint comprises a sheet having a thickness ranging from about 10 to about 100 micrometers. For example, in one such embodiment, the constraint comprises a stainless steel sheet (e.g., SS316) having a thickness of about 30 μm. By way of further example, in another such embodiment, the constraint comprises an aluminum sheet (e.g., 7075-T6) having a thickness of about 40 μm. By way of further example, in another such embodiment, the constraint comprises a zirconia sheet (e.g., Coorstek YZTP) having a thickness of about 30 μm. By way of further example, in another such embodiment, the constraint comprises an E-glass UD / epoxy 0 degree sheet having a thickness of about 75 μm. By way of further example, in another such embodiment, the constraint comprises 12 μm carbon fiber with a packing density of >50%.

[0049] In certain embodiments, the compression and / or tension members of the restraint include a porous material. Generally, the porous material facilitates access of the electrolyte to the electrode assembly. For example, in some embodiments, the compression and / or tension members can have a porosity of at least 0.25. By way of further example, in some embodiments, the compression and / or tension members can have a porosity of at least 0.375. By way of further example, in some embodiments, the compression and / or tension members can have a porosity of at least 0.5. By way of further example, in some embodiments, the compression and / or tension members can have a porosity of at least 0.625. By way of further example, in some embodiments, the compression and / or tension members can have a porosity of at least 0.75.

[0050] In yet another embodiment, the constraint 130 includes one or more compression members that are internal to the electrode assembly 120. For example, referring now to FIG. 6B, a cross-sectional view of an embodiment of an electrode assembly 120 having a constraint 130 with an internal compression member 132a is shown. In the embodiment shown in FIG. 6B, the constraint 130 can include first and second compression members 132, 134 at the longitudinal end faces 122, 124 of the electrode assembly 120, respectively. However, additionally and / or alternatively, the constraint 130 can further include at least one internal compression member 132a disposed in an interior region other than the longitudinal end faces 122, 124 of the electrode assembly. The internal compression member 132a is connected to the tension members 133, 135 to apply a compressive pressure between the internal compression member 132a and another compression member (e.g., one or more compression members 132, 134 at the longitudinal end faces 122, 124 of the electrode assembly 120) and / or to a portion of the electrode assembly 120 having one or more other internal compression members 132. With reference to the embodiment shown in FIG. 6B, the internal compression member 132a can be provided spaced apart along the longitudinal axis (in the stacking direction D) away from the first and second longitudinal end faces 122, 124 of the electrode assembly 120, respectively (e.g., toward a central region of the electrode assembly 120). The internal compression member 132a can be connected to the tension members 133, 135 at a location interior to the electrode assembly end faces 122, 124. In one embodiment, at least one internal compression member 132a is provided at a location interior to the end faces 122, 124 in addition to the compression members 132, 134 provided at the electrode assembly end faces 122, 124. In another embodiment, the constraint 130 includes an internal compression member 132a at a location interior to the electrode assembly 120 spaced inwardly from the longitudinal end faces 122, 124, with or without compression members 132, 134 at the longitudinal end faces 122, 124. In yet another embodiment, the constraint 130 includes an internal compression member 132a at a location interior to the electrode assembly spaced inwardly from the longitudinal end faces 122, 124 without a compression member 132, 134 at the longitudinal end faces 122, 124.In one embodiment, the internal compression member 132a can be understood to cooperate with one or more compression members 132, 134 and / or other internal compression members 132a to apply a compressive pressure to portions of the electrode assembly 120 that lie longitudinally between the internal compression member 132a and the longitudinal surfaces 122, 124 of the electrode assembly 120, where the compression member 132, 134 may be located, and / or to apply a compressive pressure to portions of the electrode assembly 120 that lie longitudinally between the internal compression member 132a and another internal compression member 132a. In one version, at least one of the internal compression members 132a includes at least a portion of an electrode structure 151 or a counter electrode structure 152, as described in more detail below. For example, the internal compression member 132a can include at least a portion of a counter electrode active material, a separator, an electrode current collector, a counter electrode current collector, an electrode backbone, and a counter electrode backbone.

[0051] According to one embodiment, as described above, the constraint 130 can include an internal compression member 132a that is part of the internal structure of the electrode assembly 106 (e.g., part of the electrode 151 and / or the counter electrode structure 152). In one embodiment, by providing compression between structures within the electrode assembly 120, a tightly constrained structure can be achieved that adequately compensates for strains generated by the elongation of the electrode structure 120. For example, in one embodiment, one or more internal compression members 132 can be arranged in tension with each other via connecting tension members 133, 134, thereby acting in cooperation with the compression members 132, 134 at the longitudinal end faces 122, 124 of the electrode assembly 120 to inhibit elongation in a direction parallel to the longitudinal direction. In yet another embodiment, elongation of the electrode structure 151 (e.g., an anode structure) can be countered by compression via one or more internal compression members 132a that correspond to the portions of the counter electrode structure 152 (e.g., anode) that are arranged in tension with each other via tension members 133, 135.

[0052] Generally, in certain embodiments, the components of the constraint 130 may be embodied as electrodes 151 and / or counter-electrode structures 152 in the electrode assembly 120, respectively, to provide effective constraint as well as to more efficiently utilize the volume of the electrode assembly 120 without unduly increasing the size of a secondary battery having the electrode assembly 120. For example, in one embodiment, the constraint 130 may include tension members 133, 135 functioning as an internal compression member 132a attached to one or more of the electrode structures 151 and / or counter-electrode structures 152. As a further example, in certain embodiments, at least one internal compression member 132a may be embodied as an assembly of the electrode structures 151. As a further example, in certain embodiments, at least one internal compression member 132a may be embodied as an assembly of the counter-electrode structures 152.

[0053] 6C, a Cartesian coordinate system for reference is shown having a vertical axis (Z-axis), a longitudinal axis (Y-axis), and a horizontal axis (X-axis), with the X-axis oriented out of the plane of the page, and the designation of the stack direction D as described above being parallel to the Y-axis. More specifically, FIG. 7 shows a cross-sectional view of an electrode assembly 120 having a constraint 130 having compression members 132, 134 on its longitudinal surfaces and at least one internal compression member 132a. The constraint 130 includes the compression members 132, 134, as well as the internal compression member embodied as a collection of electrode structures 151 and / or a collection of counter-electrode structures 152. Thus, in this embodiment, the at least one internal compression member 132a, the electrode structures 151, and / or the counter-electrode structures 152 can be understood to be interchangeable. Furthermore, the separator 150 can also form part of the internal compression member 132a. More specifically, FIG. 6C illustrates one embodiment of a flush connection of the inner compression member 132a to the corresponding electrode 151 or counter electrode structure 152. The flush connection can further include a layer of adhesive 182 of other adhesive means between the tension members 133, 135 and the inner compression member 132a. The layer of adhesive 182 secures the inner compression member 132a to the tension members 133, 135 so that the inner compression member 132a can be held in tension with other compression members (e.g., other inner compression members or compression members at the longitudinal ends of the electrode assembly 120).

[0054] Further shown in Figure 6C is a member of an electrode assembly 151 having, in one embodiment, an electrode active material layer 160, an electrode current collector 163 (e.g., an ionic porous electrode current collector), and an electrode backbone 165 supporting the electrode active material layer 160 and the electrode current collector 163. Similarly, in one embodiment, a member of a counter electrode assembly 152 is shown in Figure 6C having a counter electrode active material layer 167, a counter electrode current collector 169, and a counter electrode backbone 171 supporting the counter electrode active material layer 167 and the counter electrode current collector 169.

[0055] Without being bound to a particular theory (e.g., as in FIG. 6C ), in certain embodiments, the members of the electrode assembly 151 include an electrode active material layer 160, an electrode current collector 163, and an electrode backbone 165 that supports the electrode active material layer 160 and the electrode current collector 163. Similarly, in certain embodiments, the members of the counter electrode assembly 152 include a counter electrode active material layer 167, a counter electrode current collector 169, and a counter electrode backbone 171 that supports the counter electrode active material layer 167 and the counter electrode current collector 169. In one embodiment, at least a portion of any of the electrode and counter electrode structures 151, 152 (e.g., current collectors 163, 169, backbones 165, 171, counter electrode active material layer 167, and separator 130) can function as part of or as the entire inner compression member 132a (e.g., by being connected to tension members 133, 135 or otherwise placed in tension with one or more other inner or outer compression members 132, 134). In one embodiment, the inner compression member 132a can be connected to the tension members 133, 135 by at least one of gluing, welding, bonding, adhesion, or similar connecting means. 6C shows an inner compression member 132a corresponding to both the electrode and counter electrode structures 151, 152 (i.e., both the electrode and counter electrode structures are placed in tension with each other by being connected to tension members 133, 135), in other embodiments, only one of the electrode and / or counter electrode structures can function as the inner compression member 132a (e.g., by being adhered to tension members 133, 135) and / or only a portion of the electrode or counter electrode structures 151, 152 can function as the inner compression member 132a. For example, in one embodiment, a current collector (e.g., at least one of electrode current collector 163 and / or counter electrode current collector 152) can function as the inner compression member 132 (e.g., by being adhered to tension members 133, 135).

[0056] 4, to complete the fabrication of the secondary battery 100, the battery enclosure 102 is filled with a non-aqueous electrolyte (not shown) and the lid 104 is folded (along crease 106) and sealed to the top surface 108. When fully assembled, the sealed secondary battery occupies a volume bounded by its exterior surfaces (i.e., the displaced volume), the secondary battery enclosure 102 occupies a volume corresponding to the displaced volume of the battery (including the lid 104) that is less than its interior volume (i.e., the columnar volume bounded by the interior surfaces 103A, 103B, 103C, 103D, 103E, and the lid 104), and each restraint 130 of the set 110 occupies a volume corresponding to its respective displaced volume. Thus, in combination, the battery enclosure and restraints occupy only 75% of the volume bounded by the exterior surfaces of the battery enclosure (i.e., the displaced volume of the battery). For example, in one such embodiment, the restraint and battery enclosure, combined, occupy only 60% of the volume bounded by the exterior surface of the battery enclosure. By way of a further example, in one such embodiment, the restraint and battery enclosure, combined, occupy only 45% of the volume bounded by the exterior surface of the battery enclosure. By way of a further example, in one such embodiment, the restraint and battery enclosure, combined, occupy only 30% of the volume bounded by the exterior surface of the battery enclosure. By way of a further example, in one such embodiment, the restraint and battery enclosure, combined, occupy only 20% of the volume bounded by the exterior surface of the battery enclosure.

[0057] For ease of illustration in FIG. 4, the secondary battery 100 includes only one set 110 of electrode assemblies, and the set includes only six electrode assemblies 120. In practice, the secondary battery includes two or more sets of electrode assemblies, and each of the sets can be arranged laterally (e.g., in a relative direction within the XY plane of the Cartesian coordinate system of FIG. 4) or vertically (e.g., in a direction substantially parallel to the Z axis of the Cartesian coordinate system of FIG. 4) relative to one another. Also, in each of these embodiments, each of the sets of electrode assemblies can include one or more electrode assemblies. For example, in certain embodiments, the secondary battery can include one, two, or more sets of electrode assemblies, and each such set includes one or more electrode assemblies (e.g., 1, 2, 3, 4, 5, 6, 10, 15, or more electrode assemblies within each such set), and when the battery includes two or more such sets, the sets can be arranged laterally or vertically relative to the electrode assemblies of the other sets that make up the secondary battery. In each of these various embodiments, each individual electrode assembly can have its own constraint (i.e., a one-to-one relationship between the electrode assembly and the constraint), two or more electrode assemblies may have a common constraint (i.e., one constraint for two or more electrode assemblies), or two or more electrode assemblies may share components of a constraint (i.e., two or more electrode assemblies may have a common compression and / or tension member).

[0058] 12A, in one exemplary embodiment, the electrode assembly 120 comprises first and second longitudinal end faces 121, 122 and an outer surface including outer surfaces 123, 124, 125, 126. The electrode assembly 120 further comprises a collection of electrode structures 151 and a collection of counter-electrode structures 152 stacked in an electrode stacking direction D parallel to a longitudinal axis A extending between the opposing first and second longitudinal end faces 121, 122. The electrode structures and counter-electrode structures 151, 152 are stacked in an alternating (e.g., interlaced) manner such that each member of an electrode assembly is substantially between two members of a counter-electrode assembly and each member of a counter-electrode assembly is substantially between two members of an electrode assembly. For example, except for the first and last electrode or counter-electrode structure in an alternating series, in one embodiment, each electrode structure in an alternating series is between two counter-electrode structures and each counter-electrode structure in a series is between two electrode structures. Additionally, the ratio of the surface area of ​​the non-thin electrode and counter-electrode structures to their respective geometric footprints on the virtual backplane (e.g., outer surfaces 126, 127, respectively) can be at least about 5, at least about 10, at least about 50, at least about 100, or even at least about 500.

[0059] 12A, with one exception, each member 151 of an assembly of electrode structures is between two members 152 of a counter electrode assembly, and with one exception, each member 152 of an assembly of counter electrode structures is between two members 151 of an assembly of electrode structures. More generally, in one embodiment, the electrode and counter electrode assemblies each have N members, each of the N-1 electrode assembly members is between two counter electrode structures, and each of the N-1 counter electrode assembly members is between the electrode structures, and N is at least 2. For example, in one embodiment, N is at least 4, at least 5, at least 10, at least 25, at least 50, or even at least 100 (as shown in FIG. 4).

[0060] 12B and 12C, the projection of the members of the electrode and counter-electrode assemblies onto the first longitudinal end face 122 encloses a first projected area 162, and the projection of the members of the electrode and counter-electrode assemblies onto the second longitudinal end face 124 encloses a second projected area 164. In general, the first and second projected areas 162, 164 typically include a substantial portion of the surface area of ​​the first and second longitudinal end faces 122, 124, respectively. For example, in one embodiment, the first and second projected areas each include at least 50% of the surface area of ​​the first and second longitudinal end faces. As a further example, in one such embodiment, the first and second projected areas each include at least 75% of the surface area of ​​the first and second longitudinal end faces, respectively. By way of further example, in one such embodiment, the first and second projected areas each comprise at least 90% of the surface area of ​​the first and second longitudinal end faces, respectively.

[0061] The members of the electrode and counter electrode assemblies include electroactive materials capable of absorbing and releasing carrier ions (e.g., lithium ions, sodium ions, potassium ions, calcium ions, magnesium ions, or aluminum ions). In some embodiments, the member 151 of the electrode structure assembly includes an electroactive material that is anode active (sometimes referred to as a negative electrode), and the member 152 of the counter electrode structure assembly includes an electroactive material that is cathode active (sometimes referred to as a positive electrode). In other embodiments, the member 151 of the electrode structure assembly includes an electroactive material that is cathode active, and the member 152 of the counter electrode structure assembly includes an electroactive material that is anode active. In each of the embodiments and examples described in this paragraph, the negative electrode active material can be a granular aggregate electrode or a monolithic electrode.

[0062] Exemplary anode active electroactive materials include carbon materials (e.g., graphite, and soft or hard carbon), or any of the metals, metalloids, alloys, oxides, and compounds that can form an alloy with lithium. Specific examples of metals or metalloids that can constitute the anode material include tin, lead, magnesium, aluminum, boron, gallium, silicon, indium, zirconium, germanium, bismuth, cadmium, antimony, silver, zinc, arsenic, hafnium, yttrium, and palladium. In one exemplary embodiment, the anode active material includes aluminum, tin, or silicon, or an oxide thereof, a nitride thereof, a fluoride thereof, or another alloy thereof. In another exemplary embodiment, the anode active material includes silicon or an alloy thereof.

[0063] Exemplary negative electrode active materials include any of a wide range of negative electrode active materials. For example, in a lithium ion battery, the negative electrode active material can include a negative electrode material selected from transition metal oxides, transition metal sulfides, transition metal nitrides, lithium transition metal oxides, lithium transition metal sulfides, and lithium transition metal nitrides. The transition metal elements of these transition metal oxides, transition metal sulfides, and transition metal nitrides can include metal elements having a d-shell or an f-shell. Specific examples of such metal elements are 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 negative electrode active materials include LiCoO2, LiNi 0.5 Mn 1.5 O4, Li(Ni x Co y Al2)O2, LiFePO4, Li2MnO4, V2O5, molybdenum oxysulfide, phosphates, silicates, vanadates, and combinations thereof.

[0064] In one embodiment, the positive electrode active material is microstructured to provide a large porosity to accommodate volume expansion and contraction when lithium ions (or other carrier ions) are incorporated into or separated from the negative electrode active material during the charging and discharging process. Generally, the porosity of the negative electrode active material is at least 0.1. Typically, however, the porosity of the negative electrode active material is 0.8 or less. For example, in one embodiment, the porosity of the negative electrode active material is about 0.15 to about 0.75. As a further example, in one embodiment, the porosity of the negative electrode active material is about 0.2 to about 0.7. As a further example, in one embodiment, the porosity of the negative electrode active material is about 0.25 to about 0.6.

[0065] Depending on the composition of the microstructured negative electrode active material and the method of its formation, the microstructured negative electrode active material may include macroporous, microporous, or mesoporous material layers, or combinations thereof (e.g., a combination of microporous and mesoporous, or a combination of mesoporous and macroporous). Microporous materials are typically characterized by pore dimensions of less than 10 nm, wall dimensions of less than 10 nm, pore depths of 1-50 micrometers, and pore morphologies generally characterized by a "spongy" irregular appearance (smooth, non-branched walls). Mesoporous materials are typically characterized by pore dimensions of 10-50 nm, wall dimensions of 10-50 nm, pore depths of 1-100 micrometers, and pore morphologies generally characterized by somewhat well-defined branched or dendritic pores. Macroporous materials are typically characterized by pore sizes greater than 50 nm, wall sizes greater than 50 nm, pore depths of 1 to 500 micrometers, and pore morphologies that can be linear, branched, or dendritic, and smooth or rough-walled. The void volume can also include open or closed voids, or a combination thereof. In one embodiment, the void volume includes open voids. That is, the negative electrode active material includes voids with openings on the outer surface of the negative electrode active material through which lithium ions (or other carrier ions) can enter or exit the negative electrode active material, e.g., lithium ions can enter the negative electrode active material through the void openings after leaving the positive electrode active material. In another embodiment, the void volume includes closed voids. That is, the negative electrode active material includes voids surrounded by the negative electrode active material. In general, open porosity can provide a larger interfacial surface area for carrier ions, while closed porosity is less susceptible to the solid electrolyte interface, while providing space for the negative electrode active material to expand upon the ingress of carrier ions. Thus, in certain embodiments, it is preferred that the negative electrode active material includes a combination of open and closed porosity.

[0066] In one embodiment, the negative electrode active material comprises porous aluminum, tin, or silicon, or an alloy thereof. The porous silicon layer can be formed, for example, by anodization, etching (e.g., depositing a noble metal (e.g., gold, platinum, silver, or gold / palladium) on the (100) surface of single crystal silicon and etching the surface with a mixture of hydrofluoric acid and hydrogen peroxide), or other methods known in the art (e.g., patterned chemical etching). In addition, the porous negative electrode active material generally has a porosity of at least about 0.1 and less than 0.8, and a thickness of about 1 to about 100 micrometers. For example, in one embodiment, the negative electrode active material comprises porous silicon, has a thickness of about 5 to about 100 micrometers, and has a porosity of about 0.15 to about 0.75. As a further example, in one embodiment, the negative electrode active material comprises porous silicon, has a thickness of about 10 to about 80 micrometers, and has a porosity of about 0.15 to about 0.7. By way of further example, in one such embodiment, the negative electrode active material comprises porous silicon, has a thickness of about 20 to about 50 micrometers, and has a porosity of about 0.25 to about 0.6. By way of further example, in one embodiment, the negative electrode active material comprises a porous silicon alloy (e.g., nickel silicide), has a thickness of about 5 to about 100 micrometers, and has a porosity of about 0.15 to about 0.75.

[0067] In another embodiment, the negative electrode active material includes fibers of aluminum, tin, or silicon, or alloys thereof. The individual fibers can have a diameter (thickness dimension) of about 5 nm to about 10,000 nm and a length that corresponds approximately to the thickness of the negative electrode active material. The silicon fibers (nanowires) can be formed by chemical vapor deposition or other techniques known in the art (e.g., VLS (Vapor Liquid Solid) growth and SLS (Solid Liquid Solid) growth). The negative electrode active material generally has a porosity of at least about 0.1 and less than 0.8 and a thickness of about 1 to about 200 micrometers. For example, in one embodiment, the negative electrode active material includes silicon nanowires, has a thickness of about 5 to about 100 micrometers, and has a porosity of about 0.15 to about 0.75. As a further example, in one embodiment, the negative electrode active material includes silicon nanowires, has a thickness of about 10 to about 80 micrometers, and has a porosity of about 0.15 to about 0.7. By way of further example, in one such embodiment, the negative electrode active material comprises silicon nanowires, has a thickness of about 20 to about 50 micrometers, and has a porosity of about 0.25 to about 0.6. By way of further example, in one embodiment, the negative electrode active material comprises silicon alloy (e.g., nickel silicide) nanowires, has a thickness of about 5 to about 100 micrometers, and has a porosity of about 0.15 to about 0.75.

[0068] In one embodiment, the electrode assembly members include an electrode active material layer, an electrode current collector, and an electrode backbone supporting the electrode active material layer and the electrode current collector. Similarly, in one embodiment, the counter electrode assembly members include a counter electrode active material layer, a counter electrode current collector, and a counter electrode backbone supporting the counter electrode active material layer and the counter electrode current collector.

[0069] In one embodiment, each member of the electrode assembly has a bottom, a top, and a longitudinal axis (A) that extends from the bottom to the top in a direction generally perpendicular to the direction in which the alternating arrangement of the electrode structures and counter-electrode structures proceeds. E Each member of the electrode assembly has a vertical axis (A E) measured along the length (L E ), the width (W E ), and length (L E ) and width (W E ) and the height (H E Each member of the electrode assembly also has a perimeter (P E ).

[0070] The length of the electrode assembly (L E The length (L) of the electrode assembly varies depending on the energy storage device and its intended use. In general, however, the electrode assembly members typically have lengths (L) ranging from about 5 mm to about 500 mm. E For example, in one such embodiment, the electrode assembly members have a length (L E By way of further example, in one such embodiment, the electrode assembly members have a length (L E ).

[0071] Width of the electrode assembly (W E The width (W) of the electrode assembly also varies depending on the energy storage device and its intended use. In general, however, each member of the electrode assembly typically has a width (W) within the range of about 0.01 mm to 2.5 mm. E For example, in one embodiment, each member of the electrode assembly has a width (W E ) is in the range of about 0.025 mm to about 2 mm. As a further example, in one embodiment, the width (W E ) is in the range of about 0.05 mm to about 1 mm.

[0072] Height of the electrode assembly (H E The height (H) also varies depending on the energy storage device and its intended use. In general, however, the electrode assembly members typically have a height (H) within the range of about 0.05 mm to about 10 mm. EFor example, in one embodiment, each member of the electrode assembly has a height (H E ) is in the range of about 0.05 mm to about 5 mm. As a further example, in one embodiment, the height (H E ) is in the range of about 0.1 mm to about 1 mm.

[0073] The circumference of the electrode assembly member (P E ) will also vary depending on the energy storage device and its intended use. In general, however, electrode assembly members typically have a circumference (P E For example, in one embodiment, the perimeter (P E ) is in the range of about 0.1 mm to about 15 mm. As a further example, in one embodiment, the perimeter (P E ) is in the range of about 0.5 mm to about 10 mm.

[0074] Generally, the electrode assembly member has a width (W E ) and its height (H E ) E For example, in one embodiment, L E W E and H E is at least 5:1 for each member of the electrode assembly (i.e., L E W E and L E H E and L are each at least 5:1. E W E and H E and each of L is at least 10:1. E W E and H E and each of L is at least 15:1. E W Eand H E is at least 20:1 for each member of the electrode assembly.

[0075] In addition, the electrode assembly members are E ) E For example, in one embodiment, L E P E is at least 1.25:1 for each member of the electrode assembly. E P E is at least 2.5:1 for each member of the electrode assembly. E P E is at least 3.75:1, respectively, for each member of the electrode assembly.

[0076] In one embodiment, the height (H E ) width (W E ) is at least 0.4:1, respectively. For example, in one embodiment, E W E is at least 2:1 for each member of the electrode assembly. E W E and H are at least 10:1, respectively. E W E The ratio of H to H is at least 20:1, respectively. E W E and H are generally less than 1000:1, 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 WE and H are each less than 10:1. E W E to range from about 2:1 to about 100:1 for each member of the electrode assembly, respectively.

[0077] Each member of the counter electrode assembly has a bottom, a top, and a longitudinal axis (A ) extending from the bottom to the top in a direction generally perpendicular to the direction in which the alternating arrangement of the electrode structures and counter electrode structures proceeds. CE Each member of the counter electrode assembly has a vertical axis (A CE ) measured along the length (L CE ), the width (W CE ), and length (L CE ) and width (W CE ) and the height (H CE Each member of the counter electrode assembly also has a perimeter (P CE ).

[0078] The length of the counter electrode assembly (L CE The length (L) of the counter electrode assembly varies depending on the energy storage device and its intended use. In general, however, the counter electrode assembly members typically have lengths (L) ranging from about 5 mm to about 500 mm. CE For example, in one such embodiment, each member of the counter electrode assembly has a length (L CE By way of further example, in one such embodiment, each member of the counter electrode assembly has a length (L CE ).

[0079] The width of the counter electrode assembly (W CE The width (W) of the counter electrode assembly also varies depending on the energy storage device and its intended use. In general, however, each member of the counter electrode assembly typically has a width (W) within the range of about 0.01 mm to 2.5 mm. CEFor example, in one embodiment, each member of the counter electrode assembly has a width (W CE ) is in the range of about 0.025 mm to about 2 mm. By way of further example, in one embodiment, the width (W CE ) is in the range of about 0.05 mm to about 1 mm.

[0080] The height of the counter electrode assembly (H CE The height (H) also varies depending on the energy storage device and its intended use. In general, however, the members of the counter electrode assembly typically have a height (H) within the range of about 0.05 mm to about 10 mm. CE For example, in one embodiment, each member of the counter electrode assembly has a height (H CE ) is in the range of about 0.05 mm to about 5 mm. As a further example, in one embodiment, the height (H CE ) is in the range of about 0.1 mm to about 1 mm.

[0081] The periphery of the counter electrode assembly member (P CE ) also varies depending on the energy storage device and its intended use. In general, however, the counter electrode assembly members typically have a circumference (P CE For example, in one embodiment, the perimeter (P CE ) is in the range of about 0.1 mm to about 15 mm. As a further example, in one embodiment, the perimeter (P CE ) is in the range of about 0.5 mm to about 10 mm.

[0082] Generally, each member of the counter electrode assembly has a width (W CE ) and its height (H CE ) CE For example, in one embodiment, L CE W CE and H CE is at least 5:1 for each member of the counter electrode assembly (i.e., L CE WCE and L CE H CE and L are each at least 5:1. CE W CE and H CE is at least 10:1 for each member of the counter electrode assembly. CE W CE and H CE is at least 15:1 for each member of the counter electrode assembly. CE W CE and H CE is at least 20:1 for each member of the electrode assembly.

[0083] In addition, the counter electrode assembly member is CE ) CE For example, in one embodiment, L CE P CE is at least 1.25:1 for each member of the counter electrode assembly. CE P CE is at least 2.5:1 for each member of the counter electrode assembly. CE P CE is at least 3.75:1, respectively, for each member of the counter electrode assembly.

[0084] In one embodiment, the height (H CE ) width (W CE ) is at least 0.4:1, respectively. For example, in one embodiment, CE W CE The ratio of H to H is at least 2:1 for each member of the counter electrode assembly. CEW CE is at least 10:1 for each member of the counter electrode assembly. CE W CE The ratio of H to H is at least 20:1 for each member of the counter electrode assembly. CE W CE The ratio of H to H is generally less than 1000:1 for each member of the electrode assembly. CE W CE is less than 500:1 for each member of the counter electrode assembly. CE W CE and H are each less than 100:1. CE W CE and H are each less than 10:1. CE W CE to range from about 2:1 to about 100:1, respectively, for each member of the counter electrode assembly.

[0085] Referring again to FIG. 12A, an electrically insulating separator layer 153 surrounds each member 151 of the electrode structure assembly and electrically insulates each member 152 of the counter electrode structure assembly. The electrically insulating separator layer 153 typically includes a microporous separator material that can be permeated with a non-aqueous electrolyte. For example, in one embodiment, the microporous separator material includes pores having a diameter of at least 50 Å, more typically within the range of about 2500 Å, and a porosity within the range of about 25% to about 75%, more typically within the range of about 35% to about 55%. The microporous separator material also allows the non-aqueous electrolyte to permeate to allow the conduction of carrier ions between adjacent members of the electrode and counter electrode assemblies. In one embodiment, for example, disregarding the porosity of the microporous separator material, at least 70% by volume of the electrically insulating separator material layer 153 between the member 151 of the electrode structure assembly and the nearest member 152 of the counter electrode structure for ion exchange during charging or discharging (i.e., the "adjacent pair") is the microporous separator material. In other words, the microporous separator material constitutes at least 70% by volume of the electrically insulating material between the member 151 of the electrode structure assembly and the nearest member 152 of the counter electrode structure assembly. By way of further example, in one embodiment, disregarding the porosity of the microporous separator material, the microporous separator material constitutes at least 75% by volume of the electrically insulating separator material layer between the nearest pair of members 151 and 152 of the electrode structure assembly and the counter electrode structure assembly, respectively. By way of further example, in one embodiment, disregarding the porosity of the microporous separator material, the microporous separator material constitutes at least 80% by volume of the electrically insulating separator material layer between adjacent pairs of members 151 and 152 of the electrode structure assembly and counter electrode structure assembly, respectively. By way of further example, in one embodiment, disregarding the porosity of the microporous separator material, the microporous separator material constitutes at least 85% by volume of the electrically insulating separator material layer between adjacent pairs of members 151 and 152 of the electrode structure assembly and counter electrode structure assembly, respectively.By way of further example, in one embodiment, ignoring the porosity of the microporous separator material, the microporous separator material constitutes at least 90% by volume of the electrically insulating separator material layer between adjacent pairs of members 151 and 152 of the electrode structure assembly and counter electrode structure assembly, respectively. By way of further example, in one embodiment, ignoring the porosity of the microporous separator material, the microporous separator material constitutes at least 95% by volume of the electrically insulating separator material layer between adjacent pairs of members 151 and 152 of the electrode structure assembly and counter electrode structure assembly, respectively. By way of further example, in one embodiment, ignoring the porosity of the microporous separator material, the microporous separator material constitutes at least 99% by volume of the electrically insulating separator material layer between adjacent pairs of members 151 and 152 of the electrode structure assembly and counter electrode structure assembly, respectively.

[0086] In one embodiment, the microporous separator material includes a particulate material and a binder and has a porosity (void fraction) 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 250-2500 Å. The microporous separator material typically has a porosity of less than about 75%. In one embodiment, the microporous separator material has a porosity (void fraction) of at least about 25% by volume. In one embodiment, the microporous separator material has a porosity of about 35-55%.

[0087] Binders for the microporous separator material 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 (e.g., magnesium hydroxide, calcium hydroxide, etc.). For example, in one embodiment, the binder is a fluorinated polymer derived from monomers including vinylidene fluoride, hexafluoropropylene, tetrafluoropropene, etc. In another embodiment, the binder is a polyolefin (e.g., polyethylene, polypropylene, or polybutene) having any range of molecular weights and densities. In another embodiment, the binder is selected from the group consisting of ethylene-diene-propene terpolymers, 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. In another embodiment, the binder is a copolymer or blend of two or more of the above polymers.

[0088] The particulate material included in the microporous separator material can 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 in contact with the microporous separator material. For example, in one embodiment, the particulate material has a 1×10 -4 By way of further example, in one embodiment, the granular material has a conductivity for carrier ions (e.g., lithium) of less than 1×10 -5By way of further example, in one embodiment, the granular material has a conductivity for carrier ions of less than 1×10 -6 The granular material has a conductivity for carrier ions of less than 10 ... In one embodiment, the particulate material has an average particle size of about 20 nm to 2 micrometers, more typically 200 nm to 1.5 micrometers, hi one embodiment, the particulate material has an average particle size of about 500 nm to 1 micrometer.

[0089] In another embodiment, the particulate materials included in the microporous separator material may be bound by techniques such as sintering, bonding, curing, etc., while retaining a desired porosity for electrolyte intrusion to provide ionic conductivity for the function of the battery.

[0090] The microporous separator material can be deposited, for example, by electrophoretic deposition of a particulate separator material in which the particles are held together by surface energy (e.g., electrostatic attraction or van der Waals forces), slurry deposition (including spin or spray coating) of the particulate separator material, screen printing, dip coating, and electrostatic spray deposition. A binder may be included in the deposition process, for example, the particulate material can be slurry deposited with a dissolved binder that precipitates by solvent evaporation, electrophoretically deposited in the presence of a dissolved binder material, or co-electrophoretically deposited with a binder and insulating particles, etc. Alternatively or additionally, the binder may be added after the particles are deposited in or on the electrode structure. For example, the particulate material can be dispersed in an organic binder solution and dip or spray coated, followed by drying, dissolving, or crosslinking the binder material to provide adhesive strength.

[0091] In the assembled energy storage device, the microporous separator material is infiltrated with a non-aqueous electrolyte suitable for use as a secondary battery electrolyte. Typically, the non-aqueous electrolyte comprises a lithium salt dissolved in an organic solvent. Exemplary lithium salts include inorganic lithium salts (e.g., LiClO4, LiBF4, LiPF6, LiAsF6, LiCl, and LiBr) and organic lithium salts (e.g., LiB(C6H5)4, LiN(SO2CF3)2, LiN(SO2CF3)3, LiNSO2CF3, LiNSO2CF5, LiNSO2C4F9, LiNSO2C5F 11 , LiNSO2C6F 13 , and LiNSO2C7F 15) Exemplary organic solvents for dissolving lithium salts include cyclic esters, linear esters, cyclic ethers, and linear 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 linear esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, methylethyl carbonate, methylbutyl carbonate, methylpropyl carbonate, ethylbutyl carbonate, ethylpropyl carbonate, butylpropyl carbonate, alkyl propionates, dialkyl malonates, and alkyl acetates. 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.

[0092] 12A, 12B, and 12C, the areas of the longitudinal end faces 122, 124 of the electrode assembly that coincide with the projections of the electrode and counter-electrode assembly members onto the longitudinal end faces 162, 164, respectively, (i.e., the "projected surface areas"), are subjected to a significant compressive load imposed by the constraint 130 (see FIG. 4). For example, in one embodiment, the areas of the longitudinal end faces of the electrode assembly that coincide with the projections of the electrode and counter-electrode assembly members onto the longitudinal end faces are each under a compressive load of at least 0.7 kPa (averaged over the respective surface areas of the first and second projected surface areas, respectively). By way of further example, in one such embodiment, the areas of the longitudinal end faces of the electrode assembly that coincide with the projections of the electrode and counter-electrode assembly members onto the longitudinal end faces are each under a compressive load of at least 1.75 kPa (averaged over the respective surface areas of the first and second projected surface areas, respectively). By way of further example, in one such embodiment, the areas of the longitudinal end faces of the electrode assembly coinciding with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces of the members are each under a compressive load of at least 2.8 kPa (averaged over the respective surface areas of the first and second projected surface areas, respectively). By way of further example, in one such embodiment, the areas of the longitudinal end faces of the electrode assembly coinciding with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces of the members are each under a compressive load of at least 3.5 kPa (averaged over the respective surface areas of the first and second projected surface areas, respectively). By way of further example, in one such embodiment, the areas of the longitudinal end faces of the electrode assembly coinciding with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces of the members are each under a compressive load of at least 5.25 kPa (averaged over the respective surface areas of the first and second projected surface areas, respectively). As a further example, in one such embodiment, areas of the longitudinal end faces of the electrode assembly coinciding with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces are each under a compressive load (averaged over the surface areas of the first and second projected surface areas, respectively) of at least 7 kPa.As a further example, in one such embodiment, the areas of the longitudinal end faces of the electrode assembly that coincide with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces of the members are each under a compressive load of at least 8.75 kPa (averaged over the surface area of ​​the first and second projected surface areas, respectively). Typically, however, the areas of the longitudinal end faces of the electrode assembly that coincide with the projections of the electrode and counter-electrode assemblies onto the longitudinal end faces of the members are each under a compressive load of only about 10 kPa (averaged over the surface area of ​​the first and second projected surface areas, respectively). In each of the foregoing exemplary embodiments, the longitudinal end faces of the secondary battery of the present disclosure are under such compressive loads when the battery is charged to at least about 80% of its rated capacity.

[0093] In certain embodiments, substantially the entire longitudinal end face of the electrode assembly is under a significant compressive load (not necessarily just the first and second projected surface areas). For example, in some embodiments, generally, each longitudinal end face of the electrode assembly is under a compressive load of at least 0.7 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). For example, in one embodiment, each longitudinal end face of the electrode assembly is under a compressive load of at least 1.75 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). By way of further example, in one such embodiment, each longitudinal end face of the electrode assembly is under a compressive load of at least 2.8 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). By way of further example, in one such embodiment, each longitudinal end face of the electrode assembly is under a compressive load of at least 3.5 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). By way of further example, in one such embodiment, each longitudinal end face of the electrode assembly is under a compressive load of at least 5.25 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). By way of further example, in one such embodiment, each of the longitudinal end faces of the electrode assembly is under a compressive load of at least 7 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). By way of further example, in one such embodiment, each of the longitudinal end faces of the electrode assembly is under a compressive load of at least 8.75 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). Typically, however, the longitudinal end faces of the electrode assembly are under a compressive load of only about 10 kPa (averaged over the entire surface area of ​​each of the longitudinal end faces). In each of the above exemplary embodiments, the longitudinal end faces of the electrode assembly are under such compressive loads when the battery is charged to at least about 80% of its rated capacity.

[0094] In one embodiment, each of the first and second longitudinal ends of the electrode assembly is under a compressive load of at least 100 psi. For example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 200 psi. As a further example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 300 psi. As a further example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 400 psi. As yet another example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 500 psi. As a further example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 600 psi. As yet another example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 700 psi. As yet another example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 800 psi. As a further example, in one embodiment, each of the first and second longitudinal ends is under a compressive load of at least 900 psi. In yet another example, each of the first and second longitudinal ends is under a compressive load of at least 1000 psi.

[0095] Referring again to FIG. 4 and FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D, according to one aspect of the present disclosure, the tension members 133, 135 are preferably relatively close to the outer surface to inhibit buckling of the electrode assembly in response to a compressive force applied to the longitudinal end surface. In the embodiment shown in FIG. 5A-FIG. 5D, for example, the tension members 133, 135 contact the outer surface 123, 125, respectively. However, in other embodiments, a gap may exist between the tension members and the outer surface. Generally, however, the distance between the tension members and the outer surface of the electrode assembly is less than 50% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension members and the outer surface of the electrode assembly. As a further example, in one such embodiment, the distance between the tension members and the outer surface of the electrode assembly is less than 40% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension members and the outer surface of the electrode assembly. By way of further example, in one such embodiment, the distance between the tension member and the outer surface of the electrode assembly is less than 30% of the smallest ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly. By way of further example, in one such embodiment, the distance between the tension member and the outer surface of the electrode assembly is less than 20% of the smallest ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly. By way of further example, in one such embodiment, the distance between the tension member and the outer surface of the electrode assembly is less than 10% of the smallest ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly. By way of further example, in one such embodiment, the distance between the tension member and the outer surface of the electrode assembly is less than 5% of the smallest ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0096] Referring now to FIG. 7, there is seen an exploded view of another embodiment of a secondary battery of the present disclosure, generally designated 100. The secondary battery includes a battery enclosure 102 and a set 110 of electrode assemblies 120 within the battery enclosure 102, each of the electrode assemblies having a first longitudinal end face 122, an opposing second longitudinal end face 124 (separated from the first longitudinal end face 122 along a longitudinal axis (not shown) parallel to the "Y-axis" of the imaginary Cartesian coordinate system of FIG. 7), and an outer surface including outer surfaces 123, 125, 126, 127 (see FIG. 4). In contrast to the embodiment shown in FIG. 4, in this embodiment, individual constraints 130 impose a compressive force on the first and second longitudinal surfaces of each of the electrode assemblies of the set 110. As previously mentioned, the combined surface area of ​​the opposing first and second longitudinal end faces of each electrode assembly in the set 110 is less than 50% of each of the total surface areas of the electrode assemblies in the set. The tension members of the constraint 130 pull the compression members toward each other, thereby applying a compressive force to each of the opposing first and second longitudinal end faces of each electrode assembly in the set 110, which in turn constrains the longitudinal expansion of each electrode assembly in the set 110 (coincident with the electrode stacking direction of each electrode assembly as previously described herein). Furthermore, after the battery is formed, the constraint exerts a pressure on each electrode assembly in the set 110 in the longitudinal direction (i.e., the electrode stacking direction) that exceeds the pressure maintained on the respective electrode assembly in either of two directions perpendicular to each other and perpendicular to the longitudinal direction.

[0097] 8, 9, 10A, and 10B, in another embodiment, the constraint 130 is formed from a sheet 107 that includes slots 109, connection regions 111, and folding regions 113. To form the constraint, the sheet 107 is simply wrapped around the electrode structure 120 that is folded along the folding regions 113 (shown in FIG. 9 without the electrode structure 120) and the overlapping edges 115, 117 are welded, glued, or otherwise secured together to form the constraint that includes compression members 132, 134 (compression member 134 that, when secured together, includes overlapping edges 115, 117) and tension members 133, 135. In one such embodiment, the constraint 130 is stretched in the stacking direction D, tensioning the connection regions 111 and, as a result, applying a compressive force to the longitudinal end faces 122, 124. In another embodiment, instead of stretching the connection regions 111 and tensioning them, the connection regions are pre-tensioned prior to installation onto the electrode assembly. In another alternative embodiment, the connection regions 111 are not under tension when initially placed onto the electrode assembly, but rather, formation of the battery causes the electrode assembly to expand and induce tension (i.e., self-tension) in the connection tension members.

[0098] 11A and 11B, in another embodiment, the constraint 130 comprises one or more serpentine tension members 121 in addition to the slots 109 and connection regions 111. The serpentine tension members 121 provide a secondary tension force in embodiments where the forces are greater during forming than during cycling. In such embodiments, the straight members provide greater resistance and yield during forming, while the serpentine tension members apply less tension during cycling. As previously described, the constraint 130 can be formed by wrapping the sheet 107 around the electrode structure 120, folding it along the folding region 113, and securing the overlapping edges 115, 117 (shown in FIGS. 11A and 11B without the electrode structure 20). As the sheet 107 is wrapped around the electrode structure, the constraint 130 is stretched in the stacking direction D to place the connection regions 111 and the serpentine tension members 121 in tension, which then exerts a compressive force on the electrode structure 120 in the stacking direction D.

[0099] In general, a constraint with high strength and stiffness can inhibit the rapid growth of the electrode assembly during the formation of the battery, while a constraint with much lower strength and stiffness allows the electrode assembly to change in volume due to changes in lithiation that occur at different charge states. Also, a constraint with low stiffness and high preload (or starting load) helps control the cell impedance by maintaining a minimum force between the cathode and anode. One approach to address these conflicting requirements according to one embodiment of the present disclosure is to construct the constraint from two components. These components can be made from either (i) similar materials with different geometries, or (ii) materials with different elastic moduli and the same geometries, or (iii) a combination of elastic moduli and geometric properties to achieve the desired stiffness. In either case, the first component ("Element 1") utilizes a higher stiffness design (material or geometry driven) than the second component ("Element 2"), and elastically plastically deforms but does not shatter under the loads experienced during battery formation. Element 2 preferably only deforms elastically. In either case, the first element should prevent the second element from displacing more than it itself, by containing or otherwise supporting the second element.

[0100] In one embodiment, the constraint comprises an elastically deformable material located between the longitudinal surfaces of the electrode assembly and the compression member. In this embodiment, the elastically deformable material elastically deforms to accommodate the expansion of the electrode and elastically returns to its original thickness and shape when the electrode contracts. As a result, minimal forces can be maintained longitudinally on the electrode assembly as the electrode and / or counter-electrode expand and contract during cycling of the secondary battery.

[0101] 16, in one exemplary embodiment, the constraint 130 includes first and second elements 136, 137. In this embodiment, the compression member 132 includes compression regions 132A, 132B of the first and second elements 136, 137, respectively, that overlie the longitudinal end surface 122, the compression member 134 includes compression regions 134A and 134B of the first and second elements 136, 137, respectively, that overlie the longitudinal end surface 124, the tension member 133 also includes tension member regions 133A, 133B of the first and second elements 136, 137, respectively, that overlie the outer surface 123, and the tension member 135 includes tension member regions 135A and 135B of the first and second elements 136, 137, respectively, that overlie the outer surface 125. In this exemplary embodiment, the first element 136 is used to limit the maximum growth of the electrode assembly during cell formation or cell cycling, while the element 137 is used to hold a preload in the direction of the electrode stack direction D during the discharge state. In this exemplary embodiment, the element 136 has no preload (applies no force to the electrode assembly) before formation. The element 137 is preloaded against the electrode assembly to impose a compressive force on the first and second longitudinal end faces 122, 124. When the electrode assembly expands (e.g., when the silicon-containing anode expands upon the uptake of carrier ions during the charging process), the force on the element 136 grows rapidly due to its high stiffness, while the force on the lower stiffness element 137 rises slowly as its displacement is limited by the element 136. Above a certain force, the element 136 yields or transitions from elastic to plastic (permanent), while the element 137 remains in the elastic range. As the force continues to rise, the length of the element 136 increases permanently. Thereafter, when the force is reduced to a small value (e.g., when the silicon-containing anode contracts as carrier ions deintercalate during the discharge step), element 136 is permanently deformed and can no longer contact electrode assembly 120, allowing it to return to near its initial preload level.

[0102] 13, in another embodiment, a secondary battery 100 includes a battery enclosure 102 and a set of electrode assemblies 120 within the battery enclosure 102. As previously described, each of the electrode assemblies has a first longitudinal end surface and an opposing second longitudinal end surface separated along a longitudinal axis, and a transverse surface surrounding the longitudinal axis (see FIGS. 4 and 12A). Additionally, the set has associated restraints 130, including a top restraint member 130T and a bottom restraint member 130B, for constraining the expansion of each of the electrode assemblies in the set in an electrode stacking direction D. The top restraint member 130T and the bottom restraint member 130B each include interlocking tabs 132D, 132C that combine to form a compression member 132. The top restraint member 130T and the bottom restraint member 130B each include interlocking tabs that combine to form a compression member 134 (not shown). As with the other embodiments, each of the compression members applies a compressive force to opposing first and second longitudinal end faces, and the tension members include slots 109 and connection regions 111 as previously described.

[0103] 14, in another embodiment, a secondary battery 100 includes a battery enclosure 102, a set of electrode assemblies (not shown) within the battery enclosure 102, and an associated restraint 130 that prevents expansion of each of the electrode assemblies in the set in the electrode stack direction. The restraint 130 includes first and second shells 130R, 130L that respectively encase the first and second longitudinal halves of the set of electrode assemblies. As in the other embodiments, a first compression member 132 including elements 132E and 132F overlies a first longitudinal end face (not shown) of the electrode assemblies in the set, a second compression member (not shown) overlies a second longitudinal end face (not shown) of the electrode assemblies in the set, and a tension member overlies an outer surface of the electrode assemblies. As in the other embodiments, each of the compression members applies a compression force to the opposing first and second longitudinal end faces, and the tension member includes a slot 109 and a connection region 111 as described above.

[0104] 15, in another embodiment, a secondary battery 100 includes a battery enclosure 102, a set of electrode assemblies 120 within the battery enclosure 102, and an associated restraint 130 that prevents expansion of each of the electrode assemblies in the set in the electrode stack direction. The restraint 130 includes a series of bands 151 that surround each of the electrode assemblies and a cap 153 that is interposed between the bands 151 and the first and second longitudinal end faces (not shown) of each electrode assembly 120 in the set. In this embodiment, the portions of the bands overlying the longitudinal end faces and the caps constitute the compression members of the present disclosure, and the portions of the bands covering the outer surfaces of the electrode assemblies constitute the tension members. As with the other embodiments, each of the compression members applies a compressive force to the opposing first and second longitudinal end faces, as previously described.

[0105] In further embodiments numbered 1 to 122 below, aspects of the disclosure include the following:

[0106] EMBODIMENT 1 A secondary battery for cycling between charged and discharged states, the secondary battery comprising a battery enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the battery enclosure, and a restraint that maintains pressure on the electrode assembly as the secondary battery cycles between charged and discharged states, the electrode assembly including an assembly of electrode structures, an assembly of counter electrode structures, and an electrically insulating microporous separator material between members of the electrode assembly and the counter electrode assembly;

[0107] the electrode assembly having first and second opposed longitudinal end faces separated along a longitudinal axis and an exterior surface circumscribing the longitudinal axis and connecting the first and second longitudinal end faces, the surface area of ​​the first and second longitudinal end faces being less than 33% of a surface area of ​​the electrode assembly;

[0108] the members of the electrode assembly and the members of the counter-electrode assembly are arranged alternately in a stack direction parallel to the longitudinal axis within the electrode assembly;

[0109] a projection of the electrode assembly and the counter-electrode assembly member onto a first longitudinal surface encloses a first projection area, and a projection of the electrode assembly and the counter-electrode assembly member onto a second longitudinal surface encloses a second projection area;

[0110] the constraint comprises first and second compression members overlying the first and second projection areas, respectively, the compression members overlying an outer surface of the electrode assembly and connected by a tension member pulling the compression members toward each other;

[0111] The restraint maintains a pressure on the electrode assembly in the stack direction that exceeds pressure maintained on the electrode assembly in each of two directions that are mutually orthogonal and orthogonal to the electrode stack direction.

[0112] EMBODIMENT 2 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 0.7 kPa averaged over the surface area of ​​the first and second projected regions.

[0113] EMBODIMENT 3 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions of at least 1.75 kPa averaged over the surface area of ​​the first and second projected regions, respectively.

[0114] EMBODIMENT 4 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 2.8 kPa averaged over the surface areas of the first and second projected regions.

[0115] EMBODIMENT 5 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 3.5 kPa averaged over the surface area of ​​the first and second projected regions.

[0116] EMBODIMENT 6 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 5.25 kPa averaged over the surface areas of the first and second projected regions.

[0117] EMBODIMENT 7 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 7 kPa averaged over the surface area of ​​the first and second projected regions.

[0118] EMBODIMENT 8 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions of at least 8.75 kPa averaged over the surface areas of the first and second projected regions.

[0119] EMBODIMENT 9 2. The secondary battery of embodiment 1, wherein the restraint imposes an average compressive force on each of the first and second projected regions of at least 10 kPa averaged over the surface area of ​​the first and second projected regions, respectively.

[0120] EMBODIMENT 10 The secondary battery of any of the preceding embodiments, wherein the surface area of ​​the first and second longitudinal end faces is less than 25% of the surface area of ​​the electrode assembly.

[0121] EMBODIMENT 11 The secondary battery of any of the preceding embodiments, wherein the surface area of ​​the first and second longitudinal end faces is less than 20% of the surface area of ​​the electrode assembly.

[0122] EMBODIMENT 12 The secondary battery of any of the preceding embodiments, wherein the surface area of ​​the first and second longitudinal end faces is less than 15% of the surface area of ​​the electrode assembly.

[0123] EMBODIMENT 13 The secondary battery of any of the preceding embodiments, wherein the surface area of ​​the first and second longitudinal end faces is less than 10% of the surface area of ​​the electrode assembly.

[0124] EMBODIMENT 14 4. The secondary battery of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 60% of the volume enclosed by the battery enclosure.

[0125] EMBODIMENT 15 4. The secondary battery of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 45% of the volume enclosed by the battery enclosure.

[0126] EMBODIMENT 16 4. The secondary battery of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 30% of the volume enclosed by the battery enclosure.

[0127] EMBODIMENT 17 4. The secondary battery of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 20% of the volume enclosed by the battery enclosure.

[0128] EMBODIMENT 18 Each member of the electrode assembly has a bottom, a top, and a length L E , width W E , height H E , and a central longitudinal axis A extending from the bottom to the top of each member in a direction generally transverse to the stacking direction. E Each member of the electrode assembly has a length L E is its central vertical axis A E The width W of each member of the electrode assembly is measured in the direction E is measured in the stack direction and is the height H E is the central vertical axis A of each member E and W of each member of the electrode assembly measured in a direction perpendicular to the stack direction. E and H E L for each E The ratio of H of each member of the electrode assembly is at least 5:1, E and WE The secondary battery according to any one of the preceding embodiments, wherein the ratio of is 0.4:1 to 1000:1, respectively.

[0129] EMBODIMENT 19 The secondary battery of any of the previous embodiments, wherein the microporous separator material comprises a particulate material and a binder, has a porosity of at least 20% by volume, and is permeated by a non-aqueous liquid electrolyte.

[0130] EMBODIMENT 20 The secondary battery of any of the previous embodiments, wherein the tension member is sufficiently close to the outer surface to inhibit buckling of the electrode assembly when the secondary battery is cycled between a charged state and a discharged state.

[0131] EMBODIMENT 21 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 50% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0132] EMBODIMENT 22 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 40% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0133] EMBODIMENT 23 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 30% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0134] EMBODIMENT 24 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 20% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0135] EMBODIMENT 25 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 10% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0136] EMBODIMENT 26 The secondary battery of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 5% of the minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

[0137] EMBODIMENT 27 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 100 psi.

[0138] EMBODIMENT 28 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 200 psi.

[0139] EMBODIMENT 29 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 300 psi.

[0140] EMBODIMENT 30 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 400 psi.

[0141] EMBODIMENT 31 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 500 psi.

[0142] EMBODIMENT 32 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 600 psi.

[0143] EMBODIMENT 33 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 700 psi.

[0144] EMBODIMENT 34 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 800 psi.

[0145] EMBODIMENT 35 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 900 psi.

[0146] EMBODIMENT 36 4. The secondary battery of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 1000 psi.

[0147] EMBODIMENT 37 11. A secondary battery as in any of the preceding embodiments, wherein the secondary battery has a rated capacity, and wherein the first and second longitudinal end faces are under such compressive load when the secondary battery is charged to at least 80% of its rated capacity.

[0148] EMBODIMENT 38 4. The secondary battery of any of the previous embodiments, wherein the electrode structure comprises an anode active electroactive material and the counter electrode structure comprises a cathode active electroactive material.

[0149] EMBODIMENT 39 4. The secondary battery of any of the previous embodiments, wherein the electrode structure comprises an anode active electroactive material comprising silicon, and the counter electrode structure comprises a cathode active electroactive material.

[0150] EMBODIMENT 40 The secondary battery of any of the preceding embodiments, wherein the secondary battery includes a set of electrode assemblies including at least two electrode assemblies.

[0151] EMBODIMENT 41 40. The secondary battery of any one of embodiments 1 to 39, wherein the secondary battery comprises a set of at least two electrode assemblies, and the constraint maintains pressure on the electrode assemblies in the set when the secondary battery is cycled between a charged state and a discharged state.

[0152] EMBODIMENT 42 A secondary battery as described in any one of embodiments 1 to 39, wherein the secondary battery comprises a set of at least two electrode assemblies, and the secondary battery includes a corresponding number of constraints, each of which maintains pressure on one of the electrode assemblies in the set when the secondary battery is cycled between a charged state and a discharged state.

[0153] EMBODIMENT 43 The secondary battery of any of the previous embodiments, wherein the electrode assembly includes at least five electrode structures and at least five counter electrode structures.

[0154] EMBODIMENT 44 4. The secondary battery of any of the preceding embodiments, wherein the electrode assembly comprises at least 10 electrode structures and at least 10 counter electrode structures.

[0155] EMBODIMENT 45 The secondary battery of any of the previous embodiments, wherein the electrode assembly comprises at least 50 electrode structures and at least 50 counter electrode structures.

[0156] EMBODIMENT 46 4. The secondary battery of any of the previous embodiments, wherein the electrode assembly comprises at least 100 electrode structures and at least 100 counter electrode structures.

[0157] EMBODIMENT 47 4. The secondary battery of any of the preceding embodiments, wherein the electrode assembly comprises at least 500 electrode structures and at least 500 counter electrode structures.

[0158] EMBODIMENT 48 The secondary battery of any of the previous embodiments, wherein the constraint comprises a material having an ultimate tensile strength of at least 10,000 psi (>70 MPa).

[0159] EMBODIMENT 49 4. The secondary battery of any of the previous embodiments, wherein the constraint comprises a material compatible with the battery's electrolyte.

[0160] EMBODIMENT 50 4. The secondary battery of any of the previous embodiments, wherein the constraint comprises a material that does not significantly corrode at the floating or anode potential of the battery.

[0161] EMBODIMENT 51 The secondary battery of any of the previous embodiments, wherein the constraint comprises a material that does not significantly react or lose mechanical strength at 45°C.

[0162] EMBODIMENT 52 The secondary battery of any of the previous embodiments, wherein the constraint comprises a metal, a metal alloy, a ceramic, a glass, a plastic, or a combination thereof.

[0163] EMBODIMENT 53 The secondary battery of any of the preceding embodiments, wherein the constraint comprises a sheet of material having a thickness in the range of about 10 to about 100 micrometers.

[0164] EMBODIMENT 54 The secondary battery of any of the preceding embodiments, wherein the constraint comprises a sheet of material having a thickness in the range of about 30 to about 75 micrometers.

[0165] EMBODIMENT 55 4. The secondary battery of any of the previous embodiments, wherein the constraint comprises carbon fiber with a packing density of >50%.

[0166] EMBODIMENT 56 The secondary battery of any of the preceding embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than the pressure maintained on the electrode assembly.

[0167] EMBODIMENT 57 The secondary battery of any of the preceding embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than the pressure maintained on the electrode assembly.

[0168] EMBODIMENT 58 The secondary battery of any of the preceding embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least four times greater than the pressure maintained on the electrode assembly.

[0169] EMBODIMENT 59 The secondary battery of any of the preceding embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least five times greater than the pressure maintained on the electrode assembly.

[0170] EMBODIMENT 60 An energy storage device for cycling between a charged state and a discharged state, the energy storage device comprising an enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the enclosure, and a restraint that maintains pressure on the electrode assembly as the energy storage device cycles between a charged state and a discharged state, the electrode assembly including an assembly of electrode structures, an assembly of counter electrode structures, and an electrically insulating microporous separator material between members of the electrode assembly and the counter electrode assembly;

[0171] the electrode assembly having opposed first and second longitudinal end faces separated along a longitudinal axis and an exterior surface circumscribing the longitudinal axis and connecting the first and second longitudinal end faces, a combined surface area of ​​the first and second longitudinal end faces being less than 33% of a combined surface area of ​​the exterior surface and the first and second longitudinal end faces;

[0172] the members of the electrode assembly and the members of the counter-electrode assembly are arranged alternately in a stack direction parallel to the longitudinal axis within the electrode assembly;

[0173] the constraint comprises first and second compression members connected by at least one tension member that pulls the compression members toward each other;

[0174] The restraint maintains a pressure on the electrode assembly in the stack direction that exceeds a pressure maintained on the electrode assembly in each of two directions that are mutually orthogonal and orthogonal to the electrode stack direction.

[0175] EMBODIMENT 61 61. The energy storage device of embodiment 60, wherein the energy storage device is a secondary battery.

[0176] EMBODIMENT 62 61. An energy storage device as described in embodiment 60, wherein the restraint includes first and second compression members overlying the longitudinal end faces of the electrode assembly.

[0177] EMBODIMENT 63 The energy storage device of any of the previous embodiments, wherein the constraint includes at least one compression member within the longitudinal end surface.

[0178] EMBODIMENT 64 An energy storage device as described in any of the preceding embodiments, wherein the projections of the electrode assembly and the counter-electrode assembly members onto a first longitudinal surface enclose a first projection area and the projections of the electrode assembly and the counter-electrode assembly members onto a second longitudinal surface enclose a second projection area, the first and second projection areas respectively comprising at least 50% of the surface area of ​​the first and second longitudinal end faces.

[0179] EMBODIMENT 65 An energy storage device as described in any of the preceding embodiments, wherein the projections of the electrode assembly and counter-electrode assembly members onto the first longitudinal surface enclose a first projection area, the projections of the electrode assembly and counter-electrode assembly members onto the second longitudinal surface enclose a second projection area, and the constraint imposes an average compressive force of at least 0.7 kPa on each of the first and second projection areas, respectively.

[0180] EMBODIMENT 66 10. The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 1.75 kPa averaged over a surface area of ​​the first and second projected regions.

[0181] EMBODIMENT 67 10. The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 2.8 kPa averaged over a surface area of ​​the first and second projected regions.

[0182] EMBODIMENT 68 10. The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 3.5 kPa averaged over a surface area of ​​the first and second projected regions.

[0183] EMBODIMENT 69 10. The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 5.25 kPa averaged over a surface area of ​​the first and second projected regions.

[0184] EMBODIMENT 70 The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 7 kPa averaged over a surface area of ​​the first and second projected regions.

[0185] EMBODIMENT 71 The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions of at least 8.75 kPa averaged over a surface area of ​​the first and second projected regions.

[0186] EMBODIMENT 72 The energy storage device of any of the preceding embodiments, wherein the constraint imposes an average compressive force on each of the first and second projected regions, respectively, of at least 10 kPa averaged over a surface area of ​​the first and second projected regions.

[0187] EMBODIMENT 73 13. The energy storage device of any of the preceding embodiments, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 25% of a surface area of ​​the electrode assembly.

[0188] EMBODIMENT 74 13. The energy storage device of any of the preceding embodiments, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 20% of a surface area of ​​the electrode assembly.

[0189] EMBODIMENT 75 13. The energy storage device of any of the preceding embodiments, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 15% of a surface area of ​​the electrode assembly.

[0190] EMBODIMENT 76 11. The energy storage device of any of the preceding embodiments, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 10% of a surface area of ​​the electrode assembly.

[0191] EMBODIMENT 77 13. The energy storage device of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 60% of a volume enclosed by the enclosure.

[0192] EMBODIMENT 78 13. The energy storage device of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 45% of a volume enclosed by the enclosure.

[0193] EMBODIMENT 79 13. The energy storage device of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 30% of a volume enclosed by the enclosure.

[0194] EMBODIMENT 80 13. The energy storage device of any of the previous embodiments, wherein the restraint and enclosure have a combined volume that is less than 20% of a volume enclosed by the enclosure.

[0195] Embodiment 81 Each member of the electrode assembly has a bottom, a top, and a length L E , width W E , height H E , and a central longitudinal axis A extending from the bottom to the top of each member in a direction generally transverse to the stacking direction. E Each member of the electrode assembly has a length L E is its central vertical axis A EThe width W of each member of the electrode assembly is measured in the direction E is measured in the stack direction and is the height H E is the central vertical axis A of each member E and W of each member of the electrode assembly measured in a direction perpendicular to the stack direction. E and H E L for each E The ratio of W of each member of the electrode assembly is at least 5:1, E H E The energy storage device according to any of the previous embodiments, wherein the ratio of H to Mn is 0.4:1 to 1000:1, respectively.

[0196] EMBODIMENT 82 13. The energy storage device of any of the previous embodiments, wherein the microporous separator material comprises a particulate material and a binder, has a porosity of at least 20% by volume, and is infiltrated by a non-aqueous liquid electrolyte.

[0197] EMBODIMENT 83 13. The energy storage device of any of the preceding embodiments, wherein the tension member is sufficiently close to the outer surface to inhibit buckling of the electrode assembly when the energy storage device is cycled between a charged state and a discharged state.

[0198] EMBODIMENT 84 The energy storage device of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 50% of the minimum ferret diameter of the electrode assembly.

[0199] EMBODIMENT 85 The energy storage device of any of the previous embodiments, wherein the distance between the tension member and the outer surface is less than 40% of the minimum ferret diameter of the electrode assembly.

[0200] EMBODIMENT 86 The energy storage device of any of the previous embodiments, wherein the distance between the tension member and the outer surface is less than 30% of the minimum ferret diameter of the electrode assembly.

[0201] EMBODIMENT 87 The energy storage device of any of the previous embodiments, wherein the distance between the tension member and the outer surface is less than 20% of the minimum ferret diameter of the electrode assembly.

[0202] EMBODIMENT 88 The energy storage device of any of the previous embodiments, wherein the distance between the tension member and the outer surface is less than 10% of the minimum ferret diameter of the electrode assembly.

[0203] EMBODIMENT 89 The energy storage device of any of the preceding embodiments, wherein the distance between the tension member and the outer surface is less than 5% of the minimum ferret diameter of the electrode assembly.

[0204] EMBODIMENT 90 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 100 psi.

[0205] EMBODIMENT 91 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 200 psi.

[0206] EMBODIMENT 92 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 300 psi.

[0207] EMBODIMENT 93 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 400 psi.

[0208] EMBODIMENT 94 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 500 psi.

[0209] EMBODIMENT 95 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 600 psi.

[0210] EMBODIMENT 96 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 700 psi.

[0211] EMBODIMENT 97 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 800 psi.

[0212] EMBODIMENT 98 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 900 psi.

[0213] EMBODIMENT 99 13. The energy storage device of any of the preceding embodiments, wherein each of the first and second longitudinal ends is under a compressive load of at least 1000 psi.

[0214] EMBODIMENT 100 11. The energy storage device of any of the preceding embodiments, wherein the energy storage device has a rated capacity, and wherein the first and second longitudinal end faces are under such compressive load when the energy storage device is charged to at least 80% of its rated capacity.

[0215] EMBODIMENT 101 13. The energy storage device of any of the previous embodiments, wherein the electrode structure comprises an anode active electroactive material and the counter electrode structure comprises a cathode active electroactive material.

[0216] EMBODIMENT 102 13. The energy storage device of any of the previous embodiments, wherein the electrode structure comprises an anodically active electroactive material comprising silicon and the counter electrode structure comprises a cathodically active electroactive material.

[0217] EMBODIMENT 103 The energy storage device of any of the preceding embodiments, wherein the energy storage device includes a set of electrode assemblies including at least two electrode assemblies.

[0218] EMBODIMENT 104 An energy storage device as described in any of embodiments 60 to 103, wherein the energy storage device comprises a set of at least two electrode assemblies, and the constraint maintains pressure on the electrode assemblies in the set when the energy storage device is cycled between a charged state and a discharged state.

[0219] EMBODIMENT 105 An energy storage device as described in any of embodiments 60 to 103, wherein the energy storage device comprises a set of at least two electrode assemblies and a corresponding number of constraints, each of which maintains pressure on one of the electrode assemblies in the set when the energy storage device is cycled between a charged state and a discharged state.

[0220] EMBODIMENT 106 The energy storage device of any of the previous embodiments, wherein the electrode assembly includes at least five electrode structures and at least five counter electrode structures.

[0221] EMBODIMENT 107 13. The energy storage device of any of the previous embodiments, wherein the electrode assembly includes at least 10 electrode structures and at least 10 counter electrode structures.

[0222] EMBODIMENT 108 13. The energy storage device of any of the previous embodiments, wherein the electrode assembly comprises at least 50 electrode structures and at least 50 counter electrode structures.

[0223] EMBODIMENT 109 13. The energy storage device of any of the previous embodiments, wherein the electrode assembly comprises at least 100 electrode structures and at least 100 counter electrode structures.

[0224] Embodiment 110 13. The energy storage device of any of the previous embodiments, wherein the electrode assembly comprises at least 500 electrode structures and at least 500 counter electrode structures.

[0225] EMBODIMENT 111 13. The energy storage device of any of the previous embodiments, wherein the constraint comprises a material having an ultimate tensile strength of at least 10,000 psi (>70 MPa).

[0226] EMBODIMENT 112 13. The energy storage device of any of the previous embodiments, wherein the constraint comprises a material compatible with the electrolyte.

[0227] EMBODIMENT 113 13. The energy storage device of any of the previous embodiments, wherein the constraint comprises a material that does not significantly corrode at the floating or anodic potential of the energy storage device.

[0228] EMBODIMENT 114 The energy storage device of any of the previous embodiments, wherein the constraint comprises a material that does not significantly react or lose mechanical strength at 45°C.

[0229] EMBODIMENT 115 13. The energy storage device of any of the previous embodiments, wherein the constraint comprises a metal, a metal alloy, a ceramic, a glass, a plastic, or a combination thereof.

[0230] EMBODIMENT 116 The energy storage device of any of the previous embodiments, wherein the constraint comprises a sheet of material having a thickness in the range of about 10 to about 100 micrometers.

[0231] EMBODIMENT 117 The energy storage device of any of the previous embodiments, wherein the constraint comprises a sheet of material having a thickness in the range of about 30 to about 75 micrometers.

[0232] EMBODIMENT 118 13. The energy storage device of any of the previous embodiments, wherein the constraint comprises carbon fiber with a packing density of >50%.

[0233] EMBODIMENT 119 An energy storage device as described in any of the previous embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than the pressure maintained on the electrode assembly.

[0234] Embodiment 120 An energy storage device as described in any of the previous embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than the pressure maintained on the electrode assembly.

[0235] EMBODIMENT 121 An energy storage device as described in any of the previous embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least four times greater than the pressure maintained on the electrode assembly.

[0236] EMBODIMENT 122 An energy storage device as described in any of the previous embodiments, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least five times greater than the pressure maintained on the electrode assembly.

[0237] Since various changes can be made in the above articles, compositions, and methods without departing from the scope of the present disclosure, it is intended that all matter shown in the above description and accompanying drawings be interpreted as illustrative and not limiting.

[0238] All directional descriptors (eg, up, down, left, right, etc.) are used only for ease of reference with respect to the drawings and are not meant as limiting.

Claims

1. 1. An energy storage device for cycling between a charged state and a discharged state, the energy storage device comprising: an enclosure, an electrode assembly and a non-aqueous liquid electrolyte within the enclosure, and a restraint that maintains pressure on the electrode assembly as the energy storage device cycles between a charged state and a discharged state, the electrode assembly including an assembly of electrode structures, an assembly of counter electrode structures, and an electrically insulating microporous separator material between members of the electrode assembly and the counter electrode assembly; the electrode assembly having opposed first and second longitudinal end faces separated along a longitudinal axis and an exterior surface circumscribing the longitudinal axis and connecting the first and second longitudinal end faces, a combined surface area of ​​the first and second longitudinal end faces being less than 33% of a combined surface area of ​​the exterior surface and the first and second longitudinal end faces; the electrode assembly members and the counter electrode assembly members are arranged alternately in a stack direction parallel to the longitudinal axis within the electrode assembly; the constraint comprises first and second compression members connected by at least one tension member that pulls the compression members toward each other; The restraint maintains a pressure on the electrode assembly in a stack direction that exceeds a pressure maintained on the electrode assembly in each of two directions that are mutually orthogonal and orthogonal to the electrode stack direction.

2. The energy storage device of claim 1 , wherein the energy storage device is a secondary battery.

3. The energy storage device of claim 1 , wherein the restraint comprises first and second compression members overlying longitudinal end faces of the electrode assembly.

4. The energy storage device of any one of claims 1 to 3, wherein the constraint comprises at least one compression member within the longitudinal end surface.

5. 5. The energy storage device of claim 1, wherein the projections of the electrode assembly and the members of the counter-electrode assembly onto the first longitudinal surface enclose a first projection area and the projections of the electrode assembly and the members of the counter-electrode assembly onto the second longitudinal surface enclose a second projection area, the first and second projection areas respectively comprising at least 50% of a surface area of ​​the first and second longitudinal end faces.

6. 6. The energy storage device of claim 1, wherein a projection of the electrode assembly and the counter-electrode assembly members onto the first longitudinal plane encloses a first projection area, a projection of the electrode assembly and the counter-electrode assembly members onto the second longitudinal plane encloses a second projection area, and the constraint imposes an average compressive force of at least 0.7 kPa averaged over a surface area of ​​the first and second projection areas, respectively, on each of the first and second projection areas.

7. 7. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 1.75 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

8. 8. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 2.8 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

9. 9. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 3.5 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

10. 10. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 5.25 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

11. 11. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 7 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

12. 12. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 8.75 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

13. 13. The energy storage device of claim 1, wherein the constraint imposes an average compressive force on each of the first and second projection regions of at least 10 kPa averaged over a surface area of ​​the first and second projection regions, respectively.

14. The energy storage device of any preceding claim, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 25% of the surface area of ​​the electrode assembly.

15. 15. The energy storage device of claim 1, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 20% of the surface area of ​​the electrode assembly.

16. 16. The energy storage device of claim 1, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 15% of the surface area of ​​the electrode assembly.

17. 17. The energy storage device of claim 1, wherein the combined surface area of ​​the first and second longitudinal end faces is less than 10% of the surface area of ​​the electrode assembly.

18. The energy storage device of any preceding claim, wherein the restraint and enclosure have a combined volume that is less than 60% of a volume enclosed by the enclosure.

19. The energy storage device of any preceding claim, wherein the restraint and enclosure have a combined volume that is less than 45% of a volume enclosed by the enclosure.

20. The energy storage device of any preceding claim, wherein the restraint and enclosure have a combined volume that is less than 30% of a volume enclosed by the enclosure.

21. The energy storage device of any preceding claim, wherein the restraint and enclosure have a combined volume that is less than 20% of a volume enclosed by the enclosure.

22. Each member of the electrode assembly has a bottom, a top, and a length L Ｅ , width W Ｅ , height H Ｅ and a central longitudinal axis A extending from the bottom to the top of each member in a direction that is generally transverse to the stacking direction. Ｅ Each member of the electrode assembly has a length L Ｅ is its central vertical axis A Ｅ The width W of each member of the electrode assembly is measured in the direction Ｅ is the height H of each member of the electrode assembly measured in the stack direction. Ｅ is the central vertical axis A of each member Ｅ and W of each member of the electrode assembly measured in a direction perpendicular to the stacking direction. Ｅ and H Ｅ L for each of Ｅ The ratio of W of each member of the electrode assembly is at least 5:1, Ｅ H Ｅ The energy storage device according to any one of claims 1 to 21, wherein the ratio of H to Mg is from 0.4:1 to 1000:1, respectively.

23. 23. The energy storage device of claim 1, wherein the microporous separator material comprises a particulate material and a binder, has a porosity of at least 20% by volume, and is permeated by the non-aqueous liquid electrolyte.

24. 24. The energy storage device of any one of claims 1 to 23, wherein the tension member is sufficiently close to the exterior surface to inhibit buckling of the electrode assembly when the energy storage device is cycled between a charged state and a discharged state.

25. 25. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 50% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

26. 26. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 40% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

27. 27. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 30% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

28. 28. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 20% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

29. 29. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 10% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

30. 30. The energy storage device of claim 1, wherein the distance between the tension member and the outer surface is less than 5% of a minimum ferret diameter of the electrode assembly, the ferret diameter being measured in the same direction as the distance between the tension member and the outer surface of the electrode assembly.

31. The energy storage device of any one of claims 1 to 30, wherein each of the first and second longitudinal end faces is under a compressive load of at least 100 psi.

32. The energy storage device of any preceding claim, wherein each of the first and second longitudinal ends is under a compressive load of at least 200 psi.

33. The energy storage device of any preceding claim, wherein each of the first and second longitudinal end faces is under a compressive load of at least 300 psi.

34. The energy storage device of any preceding claim, wherein each of the first and second longitudinal end faces is under a compressive load of at least 400 psi.

35. The energy storage device of any preceding claim, wherein each of the first and second longitudinal end faces is under a compressive load of at least 500 psi.

36. The energy storage device of any preceding claim, wherein each of the first and second longitudinal ends is under a compressive load of at least 600 psi.

37. The energy storage device of any preceding claim, wherein each of the first and second longitudinal ends is under a compressive load of at least 700 psi.

38. The energy storage device of any preceding claim, wherein each of the first and second longitudinal ends is under a compressive load of at least 800 psi.

39. The energy storage device of any preceding claim, wherein each of the first and second longitudinal end faces is under a compressive load of at least 900 psi.

40. 40. The energy storage device of any one of claims 1 to 39, wherein each of the first and second longitudinal end faces is under a compressive load of at least 1000 psi.

41. 41. The energy storage device of any one of claims 1 to 40, wherein the energy storage device has a rated capacity, and the first and second longitudinal end faces are under such compressive load when the energy storage device is charged to at least 80% of its rated capacity.

42. 42. The energy storage device of claim 1, wherein the electrode structure comprises an anode active electroactive material and the counter electrode structure comprises a cathode active electroactive material.

43. 43. The energy storage device of any preceding claim, wherein the electrode structure comprises an anodically active electroactive material comprising silicon and the counter electrode structure comprises a cathodically active electroactive material.

44. The energy storage device according to any one of claims 1 to 43, comprising a set of electrode assemblies comprising at least two electrode assemblies.

45. 45. The energy storage device of any one of claims 1 to 44, wherein the energy storage device comprises a set of at least two electrode assemblies, and the constraint maintains pressure on the electrode assemblies in the set as the energy storage device is cycled between a charged state and a discharged state.

46. 45. The energy storage device of any one of claims 1 to 44, wherein the energy storage device comprises a set of at least two electrode assemblies and a corresponding number of constraints, each of the constraints maintaining pressure on one of the electrode assemblies in the set when the energy storage device is cycled between a charged state and a discharged state.

47. 47. The energy storage device of any preceding claim, wherein the electrode assembly comprises at least five electrode structures and at least five counter electrode structures.

48. 48. The energy storage device of any one of claims 1 to 47, wherein the electrode assembly comprises at least 10 electrode structures and at least 10 counter electrode structures.

49. 49. The energy storage device of any one of claims 1 to 48, wherein the electrode assembly comprises at least 50 electrode structures and at least 50 counter electrode structures.

50. 50. The energy storage device of any one of claims 1 to 49, wherein the electrode assembly comprises at least 100 electrode structures and at least 100 counter electrode structures.

51. 51. The energy storage device of any one of claims 1 to 50, wherein the electrode assembly comprises at least 500 electrode structures and at least 500 counter electrode structures.

52. The energy storage device of any preceding claim, wherein the constraint comprises a material having an ultimate tensile strength of at least 10,000 psi (>70 MPa).

53. 53. The energy storage device of any preceding claim, wherein the constraint comprises a material that is compatible with the electrolyte.

54. 54. The energy storage device of any preceding claim, wherein the constraint comprises a material that does not significantly corrode at the floating potential or the anodic potential of the energy storage device.

55. 55. The energy storage device of any preceding claim, wherein the constraint comprises a material that does not significantly react or lose mechanical strength at 45°C.

56. 56. The energy storage device of any preceding claim, wherein the constraint comprises a metal, a metal alloy, a ceramic, a glass, a plastic, or a combination thereof.

57. 57. The energy storage device of any one of claims 1 to 56, wherein the constraint comprises a sheet of material having a thickness in a range of about 10 to about 100 micrometers.

58. 58. The energy storage device of any one of claims 1 to 57, wherein the constraint comprises a sheet of material having a thickness in a range of about 30 to about 75 micrometers.

59. 59. The energy storage device of any preceding claim, wherein the constraint comprises carbon fibre with a packing density of >50%.

60. 60. The energy storage device of claim 1, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than a pressure maintained on the electrode assembly.

61. 61. The energy storage device of claim 1, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least three times greater than a pressure maintained on the electrode assembly.

62. 62. The energy storage device of claim 1, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least four times greater than a pressure maintained on the electrode assembly.

63. 63. The energy storage device of claim 1, wherein the compression member applies a pressure to the first and second longitudinal end faces in each of two directions perpendicular to each other and perpendicular to the stack direction that is at least five times greater than a pressure maintained on the electrode assembly.

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