PATENT DOCUMENT

Publication Number: US-10115994-B2
Application Number: US-201514722077-A
Country: US
Kind Code: B2

Title: Devices and methods for reducing battery defects

Abstract:
Solid-state battery structures and methods of manufacturing solid-state batteries are disclosed. More particularly, embodiments relate to solid-state batteries having one or more subdivided electrode layers. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. An electrochemical cell, comprising:
 a cathode current collector having a continuous layer structure; 
 a cathode layer having a plurality of cathode subregions electrically connected to each other through the continuous layer structure of the cathode current collector, wherein the plurality of cathode subregions are separated by a first gap, and wherein the gap is at least partially filled by a dielectric gas; 
 an anode layer having a plurality of anode subregions positioned on each of the plurality of cathode subregions and separated by a second gap, the second gap at least partially filled by a dielectric gas; and 
 an electrolyte layer between the plurality of cathode subregions and the anode layer. 
 
     
     
       2. The electrochemical cell of  claim 1 , wherein the combined projected surface area of the cathode subregions is at least 80 percent of a total projected surface area of the cathode layer. 
     
     
       3. The electrochemical cell of  claim 2  further comprising an anode current collector electrically connected to the anode layer. 
     
     
       4. The electrochemical cell of  claim 1 , wherein the anode current collector includes a continuous layer structure, and wherein the plurality of anode subregions are electrically connected to each other through the continuous layer structure of the anode current collector. 
     
     
       5. An electrochemical cell, comprising:
 an anode current collector having a continuous layer structure; 
 an anode layer having a plurality of anode subregions electrically connected to each other through the continuous layer structure of the anode current collector; 
 an electrolyte layer between the plurality of anode subregions and a cathode layer; and 
 a cathode current collector electrically connected to the cathode layer, 
 wherein the plurality of anode subregions are separated by a first gap defined by adjacent anode subregions, the anode current collector and the electrolyte layer, and wherein the gap is at least partially filled by a dielectric gas, 
 the cathode layer includes a plurality of cathode subregions, wherein at least two anode subregions are disposed over each cathode subregion, 
 the cathode subregions are separated from each other by a second gap extending between the anode current collector and the cathode current collector, wherein the second gap is at least partially filled by a dielectric gas. 
 
     
     
       6. The electrochemical cell of  claim 5 , wherein a combined projected surface area of the anode subregions is less than 25 percent of a total projected surface area of the anode layer. 
     
     
       7. The electrochemical cell of  claim 5 , wherein the cathode subregions are electrically connected to each other through the continuous layer structure of the cathode current collector. 
     
     
       8. The electrochemical cell of  claim 7 , wherein a combined projected surface area of the cathode subregions is at least 80 percent of a total projected surface area of the cathode layer.

Description:
This application claims the benefit of U.S. Provisional Patent Application No. 62/003,509, filed May 27, 2014, and U.S. Provisional Patent Application No. 62/165,105, filed May 21, 2015, and this application hereby incorporates herein by reference those provisional patent applications. 
    
    
     BACKGROUND 
     Field 
     Embodiments relate to electrochemical devices and methods of manufacturing electrochemical devices. More particularly, embodiments relate to thin film electrochemical devices, including batteries, which incorporate one or more subdivided electrode layers. 
     Background Information 
     Solid-state batteries, such as thin-film batteries (TFBs), are known to provide better form factors, cycle life, power capability, and safety, as compared to conventional battery technologies. However, solid-state battery structures and manufacturing methods require further optimization to reduce fabrication costs and improve performance. 
     Referring to  FIG. 1 , an electrochemical cell  100 , which may be incorporated in a solid-state battery, includes a first electrode, e.g., an anode layer  102 , separated from a second electrode, e.g., a cathode layer  104 , by an electrolyte layer  106 . During manufacturing of the solid-state battery, a defect  108  may occur in the electrolyte layer  106  that causes internal short-circuiting between the electrodes. More particularly, the defect  108 , which may be a crack or pinhole extending between the anode layer  102  and the cathode layer  104 , can cause an internal, electronic leak through the electrolyte layer  106  during fabrication or operation of the battery. For example, an anode leak  110  may propagate through the defect  108  into the cathode layer  104 , causing a chemical reaction  112  that chemically reduces or over discharges some or all of the cathode layer  104  and eventually affects the entire cathode layer  104  to degrade battery performance and/or disable the battery. 
     SUMMARY 
     Embodiments of solid-state battery structures are disclosed. In an embodiment, an electrochemical cell includes a cathode layer having a group of two or more cathode subregions that are electrically separated by one or more gaps, and an electrolyte layer between the cathode subregions and an anode layer. The cathode subregions may be electrically connected to a common cathode current collector. The cathode current collector may have a continuous layer structure such that the cathode subregions are electrically connected to each other through the continuous layer structure of the cathode current collector. In an embodiment, a combined projected surface area of the cathode subregions is at least 80 percent of a total projected surface area of what would be a “filled” or solid cathode layer, i.e., one in which the gaps between the cathode sub-regions are filled with cathode material. In an embodiment, the gaps are at least partially filled by a dielectric material, e.g., a dielectric gas. An anode current collector may be located over the anode layer. An insulating layer, such as one that is inert to lithium, may be located over the anode layer. 
     The one or more gaps may also be partially filled by at least one of the electrolyte layer or the anode layer. For example, the cathode subregions may include respective sidewalls that are separated by the gaps and the anode layer may have a continuous layer structure that covers the sidewalls of the cathode subregions, and thus, is disposed in the gaps between the sidewalls. In addition to separating the sidewalls, the gaps may separate a portion of the anode layer between the sidewalls from the anode current collector that extends over plateaus of the cathode subregions. 
     In an embodiment, the anode layer includes several anode subregions separated by the one or more gaps. For example, an electrochemical cell may include an anode layer having a discontinuous layer structure. That is, the anode layer may include several anode subregions separated by one or more gaps. An electrolyte layer may be disposed between several anode subregions and a cathode layer. In an embodiment, an anode current collector extends over the anode subregions and includes a continuous layer structure such that the anode subregions are electrically connected to each other through the continuous layer structure of the anode current collector. A combined projected surface area of the anode subregions may be less than 25 percent of a total projected surface area of what would be described as a “filled” or solid anode layer. 
     In an embodiment, an electrochemical device includes two electrochemical cells that include respective cathode layers covered by respective anode layers. The cathode layers may have several cathode subregions separated by a gap. The cathode subregions may be electrically connected to a common cathode current collector, i.e., the cathode subregions of each cell may be electrically connected to each other through the respective cathode current collector. In an embodiment, the cells are stacked such that the anode layer of one cell is physically connected to the anode layer of the other cell. 
     A tab insertion space may be disposed between the cathode current collectors of the stacked cells, and an anode current collector tab may be disposed in the tab insertion space. The anode layers of the cells may include continuous layer structures that separate the tab insertion space from respective cathode current collectors. Thus, the anode current collector tab disposed in the tab insertion space may be connected to the anode layers between the cathode current collectors. In an embodiment, an insulating layer, such as an insulating layer that is also inert to lithium, may be disposed between the cathode layers and physically connected to the anode layers. 
     In an embodiment, an electrochemical cell includes an anode current collector having a continuous layer structure. An anode layer may be subdivided into anode subregions that are electrically connected to each other through the continuous layer structure of the anode current collector. An electrolyte layer may be disposed between the anode subregions and a cathode layer. In an embodiment, the anode subregions are separated by a gap that extends between the anode current collector and the electrolyte layer. The gap may be at least partially filled by a dielectric material, e.g., a dielectric gas. The cell may include a cathode current collector having a continuous layer structure that is electrically connected to the cathode layer. In an embodiment, a combined projected surface area of the anode subregions is less than 25 percent of a total projected surface area of the anode layer. 
     In an embodiment, the cathode layer of the cell includes several cathode subregions, and at least two of the anode subregions are disposed over each cathode subregion. The cathode subregions may be separated from each other by a gap that extends between the anode current collector and the cathode current collector. The gap may be at least partially filled by a dielectric material, e.g., a dielectric gas. Furthermore, the cathode subregions may be electrically connected to each other through the continuous layer structure of the cathode current collector. A combined projected surface area of the cathode subregions may be at least 80 percent of a total projected surface area of the cathode layer. 
     In an embodiment, an electrochemical device includes a stack of electrochemical cells having respective anode layers. The anode layers may include several anode subregions and the cells may include respective electrolyte layers between the anode subregions and a respective cathode layer. In an embodiment, an anode current collector having a continuous layer structure is disposed between the cathode layers and is physically connected to the anode subregions of the stacked cells. Thus, the anode subregions are electrically connected to each other through the continuous layer structure of the anode current collector. The cells may also include respective cathode current collectors that are electrically connected to the cathode layers of the respective cells. In an embodiment, a combined projected surface area of the anode subregions of each cell is less than 25 percent of a total projected surface area of the anode layers of each cell. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an electrochemical cell having a defect in an electrolyte layer. 
         FIG. 2  is a plan view of an electrochemical cell having a subdivided cathode layer in accordance with an embodiment. 
         FIG. 3  is a cross-sectional view, taken about line A-A of  FIG. 2 , of an electrochemical cell having a subdivided cathode layer in accordance with an embodiment. 
         FIGS. 4A-4B  are cross-sectional views, taken about line A-A of  FIG. 2 , of an electrochemical cell having a defect in an electrolyte layer over a subdivided cathode layer in accordance with an embodiment. 
         FIG. 5  is a plan view of an electrochemical cell having a neutralized cathode subregion in accordance with an embodiment. 
         FIG. 6  is a side view of an electrochemical cell having a subdivided cathode layer in accordance with an embodiment. 
         FIG. 7  is a plan view of an electrochemical cell having a subdivided cathode layer and an anode current collector tab in accordance with an embodiment. 
         FIGS. 8A-8B  are cross-sectional views of an electrochemical device having a defect in an electrolyte layer over a subdivided cathode layer in accordance with an embodiment. 
         FIG. 9  is a cross-sectional view of an electrochemical device having an intermediate layer between subdivided cathode layers in accordance with an embodiment. 
         FIG. 10  is a plan view of an electrochemical cell having a subdivided anode layer in accordance with an embodiment. 
         FIG. 11  is a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a subdivided anode layer in accordance with an embodiment. 
         FIG. 12  is a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a defect in an electrolyte layer under a subdivided anode layer in accordance with an embodiment. 
         FIGS. 13A-13B  are cross-sectional views, taken about line C-C of  FIG. 10 , of an electrochemical cell having a defect in an electrolyte layer under a subdivided anode layer in accordance with an embodiment. 
         FIG. 14  is a side view of an electrochemical device having an anode current collector between subdivided anode layers in accordance with an embodiment. 
         FIG. 15  is a plan view of an electrochemical cell having a subdivided anode layer over a subdivided cathode layer in accordance with an embodiment. 
         FIG. 16  is a cross-sectional view, taken about line D-D of  FIG. 15 , of an electrochemical cell having a subdivided anode layer over a subdivided cathode layer in accordance with an embodiment. 
         FIG. 17  is a flowchart illustrating a method for isolating a cathode layer from an anode leak in accordance with an embodiment. 
         FIG. 18  is a side view of an electrochemical cell during a defect detection operation in accordance with an embodiment. 
         FIG. 19  is a side view of a precursor cell having a defect in an electrolyte layer in accordance with an embodiment. 
         FIG. 20  is a side view of an electrochemical cell having a backfilled electrolyte layer in accordance with an embodiment. 
         FIG. 21  is a side view of an electrochemical cell having a defect in an electrolyte layer in accordance with an embodiment. 
         FIGS. 22A-22C  are side views of an electrochemical cell having a cathode layer isolated from an anode leak in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe structures and manufacturing methods for solid-state batteries, such as thin-film batteries. However, while some embodiments are described with specific regard to manufacturing processes or structures for integration within a solid-state battery, the embodiments are not so limited, and certain embodiments may also be applicable to other uses. For example, one or more of the embodiments described below may be used to manufacture other layered elements, such as silicon-based solar cells. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment,” or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment,” or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     In an aspect, an electrochemical cell may include several layers, such as an electrolyte layer between an anode layer and a cathode layer. Each of the layers of the electrochemical cell may be formed in a subdivided manner. For instance, one or more of the electrode layers, i.e., the anode layer or the cathode layer, may be patterned to remove gaps as per a pattern, leaving essentially islands making up the subdivided layer. Other methods for producing a “layer” of anode or cathode islands are possible. 
     In an aspect, an electrochemical cell having a cathode layer subdivided into cathode subregions is provided. For example, the cathode layer may be subdivided into several rectangular subregions separated by gaps between the subregions. Thus, each subregion may be isolated from the others, and accordingly, an anode leak that chemically reacts within one cathode subregion will not propagate to or affect the other cathode subregions. Furthermore, the gaps may also serve to provide separations between anode layer regions that are disposed over the cathode subregions, to limit the anode material that will leak into the cathode subregions, before an open circuit forms between a defect in the electrolyte layer and an anode current collector. In an embodiment, the cathode subregions may be electrically connected and physically coupled to a common, or shared, cathode current collector. Thus, the cathode subregions may be electrically connected to each other through the cathode current collector. For instance, the cathode subregions may be directly connected to the common cathode current collector, or one or more intermediate layers, such as a barrier film layer, may couple the cathode subregions with the common cathode current collector. Accordingly, fabrication yield may be increased and the electrochemical cell may be more resistant to degradation caused by anode leaks. 
     In an aspect, an electrochemical cell having an anode layer subdivided into anode subregions is provided. For example, the anode layer may be subdivided into several rectangular subregions separated by one or more gaps between the subregions. In another embodiment, a subdivided anode layer having patterned anode islands may be disposed over a subdivided cathode layer. Thus, one or more anode subregions may be located over one cathode subregion. In any case, the total projected surface area of the anode subregions may occupy a fraction of the total projected surface area of what would be the “filled” or solid anode layer. Accordingly, the probability of a defect in an electrolyte layer being adjacent to a particular anode subregion is reduced, and even if the defect does contact an anode subregion, a resulting anode leak may drain one anode subregion (thereby essentially removing that sub-region from operation) but not the other anode subregions. Furthermore, as the isolated anode subregion leaks, one or more gaps may form between the portion of the electrolyte layer that is adjacent to that anode subregion and an anode current collector; this helps reduce the likelihood of electrical discharge occurring in neighboring anode subregions (through the anode current collector and the defect). Accordingly, fabrication yield may be increased and the electrochemical cell may be more resistant to degradation caused by anode leaks. 
     In an aspect, an electrochemical cell having a repaired defect in an electrolyte layer is provided. More particularly, the electrochemical cell may be modified in a precursor state or in an assembled state to reduce the likelihood of an anode leak that could degrade the cathode layer. A repair may include filling and/or backfilling a portion of the electrolyte layer that includes the defect. A repair may include removing that portion of the anode layer that lies over the defect, and accordingly, the anode layer cannot leak through the defect into the cathode layer. A repair may include forming a channel around the defect such that even if an anode leak does occur, a first portion of the cathode layer that lies under the defect would be isolated from a second portion of the cathode layer, and thus, degradation of the cathode layer would be limited to degradation of the first portion. 
     Referring to  FIG. 2 , a plan view of an electrochemical cell having a subdivided cathode layer is shown in accordance with an embodiment. An electrochemical cell  200  may include an anode layer  202  over a cathode layer. Furthermore, the cathode layer may be subdivided into one or more cathode subregions  204 , shown with hidden lines in  FIG. 2 , spaced and patterned across the electrochemical cell  200  beneath the anode layer  202 . More particularly, the cathode subregions  204  may be separated from each other by one or more gaps  206 . For example, one or more gaps  206  may surround each cathode subregion  204  to physically isolate the cathode subregion  204  from neighboring cathode subregions  204 . 
     In an embodiment, the cathode layer may include a grid pattern, in which each cathode subregion  204  includes a rectangular surface area and is separated from adjacent cathode subregions  204  by one or more linear gaps  206  traversing the electrochemical cell  200 . That is, the cathode layer may have several cathode subregions  204  and one or more gaps  206  arranged like city blocks and streets. The grid pattern and city block metaphor may lend itself to fabrication. For example, laser scribing may be used to remove cathode layer material and form one or more gaps  206  between cathode subregions  204  after deposition of the cathode material over a substrate or after connecting the cathode material to a cathode current collector. Alternatively, shadow masking may be used to form cathode subregions  204  separated by masked regions that become the unfilled one or more gaps  206 . However, other cathode layer patterns may be used. For example, the one or more gaps  206  may be laser scribed in any shape to form isolated cathode subregions  204  that are, e.g., polygonal, conic sections, elliptical, etc., islands. The cathode subregions  204  may have a same or different shape as compared to other cathode subregions  204  in the cathode layer. 
     Regardless of the shape of the cathode subregions  204 , the cathode layer may include a total projected surface area within an electrochemical cell perimeter  208  when viewed from above, which includes a combined surface area of each cathode subregion  204  and a combined surface area of each gap  206 . For example, each cathode subregion  204  may have a projected area of a square profile with equal sides. Furthermore, each gap  206  may be formed by ablating through the cathode layer with a laser beam to create a grid of trenches with equal widths, i.e., trenches devoid of cathode material. Thus, a total projected surface area of the cathode layer within an electrochemical cell perimeter  208  may include all of the square projected surface areas as well as the projected surface area within the one or more gaps. In an embodiment, a patterned cathode area utilization, i.e., a ratio of the combined individual cathode subregion projected surface areas to the total projected surface area of the cathode layer, may be greater than 75%, with an error percentage of 2-5%. For example, the patterned cathode area utilization may be at least 80%, with an error percentage of 2-5%. In an embodiment, a grid pattern has square cathode subregions  204  with sides of 100 micron separated by one or more 10 micron gaps. Thus, the patterned cathode area utilization may be expected to be 83%. Narrowing the one or more gaps  206  or enlarging the cathode subregions  204  can increase the patterned cathode area utilization. 
     Referring to  FIG. 3 , a cross-sectional view, taken about line A-A of  FIG. 2 , of an electrochemical cell having a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, the electrochemical cell  200  may include an electrolyte layer  302  between the anode layer  202  and the cathode layer  304 , and more particularly, between the anode layer  202  and one or more cathode subregions  204 . Furthermore, a barrier film layer  306  may optionally be between the cathode layer and a cathode current collector  308 . In an embodiment, cathode current collector  308  may have a continuous layer structure, e.g., a continuous sheet or film, extending under the one or more cathode subregions  204 . As described above, each of the cathode subregions  204  may be separated by one or more gaps  206 , which defines a space between the cathode subregions  204  within the cathode layer  304 . Thus, the cathode subregions  204  may be electrically connected to each other through the continuous layer structure of cathode current collector  308 . 
     A continuous layer structure as used throughout this specification may be, but need not be, a completely filled layer. That is, a continuous layer structure may include one or more local discontinuities, such as holes, gaps, voids, etc. through a thickness of the layer, making the layer physically discontinuous, but the layer may nonetheless be electrically continuous in that an electrical potential at one location on the continuous layer structure may be essentially equal to an electrical potential at any other location on the continuous layer structure. Likewise, a continuous layer structure may be physically continuous, having no discontinuities along a layer surface, but may nonetheless be electrically discontinuous, e.g., as in the case of an insulating layer with different electrical potentials at different locations along the surface. Thus, a continuous layer structure may be one or more of physically continuous and/or electrically continuous. 
     The patterned cathode material of the cathode layer  304 , i.e., the cathode subregions  204 , may, for example, include LiCoO 2 , LiMn 2 O 4 , LiMnO 2 , LiNiO 2 , LiFePO 4 , LiVO 2 , or any mixture or chemical derivative thereof. The electrolyte layer  302  may facilitate ion transfer between the cathode subregions  204  and the anode layer  202 . Accordingly, the electrolyte layer  302  may be a solid electrolyte, which may not contain any liquid components and may not require any binder or separator materials compounded into a solid thin film. For example, the electrolyte layer  302  may include lithium phosphorous oxynitride (LiPON) or other solid state thin-film electrolytes such as LiAlF 4 , Li 3 PO 4  doped Li 4 SiS 4 . The anode layer  202  may, for example, include lithium, lithium alloys, metals that can form solid solutions or chemical compounds with lithium, or a so-called lithium-ion compound that may be used as a negative anode material in lithium-based batteries, such as Li 4 Ti 5 O 12 . 
     In an embodiment, the cathode layer subregions  204  may be electrically connected with a cathode current collector  308 , which may be an electrically conductive layer or a tab. Similarly, the anode layer  202  may be electrically connected with an anode current collector  310 , which may be an electrically conductive layer or a tab. Optionally, one or more intermediate layers may be disposed between the patterned cathode material of the cathode layer  304  or the anode layer  202  and a respective current collector. For example, a barrier film layer  306  may separate the cathode subregions  204  from the cathode current collector  308 . For example, the barrier film layer  306  may be in direct physical contact with the cathode subregions  204  and the cathode current collector  308 . The barrier film layer  306  may reduce the likelihood of contaminants and/or ions from diffusing between the cathode current collector  308  and the cathode subregions  204 . Thus, the barrier film layer  306  may include materials that are poor conductors of ions, such as borides, carbides, diamond, diamond-like carbon, silicides, nitrides, phosphides, oxides, fluorides, chlorides, bromides, iodides, and compounds thereof. Alternatively, an additional intermediate layer, such as a substrate layer may be disposed between the cathode layer  304  and the cathode current collector  308 . The substrate layer may, for example, provide electrical connectivity between the cathode subregions  204  and the cathode current collector  308  and may also provide structural support, e.g., rigidity, to the electrochemical cell  200 . Accordingly, the substrate layer may include a metal foil or another electrically conductive layer. 
     In some instances, the electrochemically active layers of the cell may be formed on one side of the substrate layer, e.g., using material deposition techniques such as physical vapor deposition, and the cathode current collector  308  may be formed separately and physically coupled to another side of the substrate layer. In other instances, the electrochemically active layers of the cell may be formed on the substrate layer, and then the electrochemically active layers may be removed from the substrate layer and physically coupled to the separately formed cathode current collector  308 . In still other instances, the electrochemically active layers of the cell may be formed, e.g., physical vapor deposited, directly on the cathode current collector  308 . Thus, there are many different ways to create an electrochemical cell  200  having several electrochemically active layers. 
     In an embodiment, the one or more gaps  206  within the patterned cathode layer  304  are at least partially filled by a dielectric  312 . More particularly, sidewalls  314  of respective cathode subregions  204  may be separated by a dielectric fluid or solid, such as a dielectric gas, e.g., an inert gas. Furthermore, multiple dielectrics or other materials may occupy the one or more gaps  206 . For example, the electrolyte layer  302  and/or the anode layer  202  may be deposited over the sidewalls  314  and the barrier film layer  306  to at least partially fill the one or more gaps  206  between the cathode subregions  204  of the patterned cathode layer  304 . The anode layer  202  and/or electrolyte layer  302  may be deposited in a continuous layer over the cathode subregions  204 , thereby forming a continuous covering across adjacent cathode subregions  204 . That is, anode layer  202  and/or electrolyte layer  302  may have a continuous layer structure, e.g., a sheet or film structure. The continuous covering may both above cathode subregions  204 , e.g., between cathode subregions  204  and anode current collector  310 , as well as laterally between cathode subregions  204 , e.g., disposed between and/or covering sidewalls  314  of adjacent cathode subregions  204 . Furthermore, since one or more of anode layer  202  or electrolyte layer  302  may be disposed as a continuous layer deposited over cathode subregions  204  and at least partially filling gaps  206 , apposing surfaces of the deposited layers may face each other. This is shown in  FIG. 3  in which laterally facing surfaces of anode layer  202  face each other across dielectric  312 , e.g., a dielectric gas. Similarly, the continuous layer structure of anode layer  202  may cover the sidewalls such that dielectric  312  separates a portion of the anode layer inside the gap  206 , e.g., the portion at the bottom of gap  206  directly above barrier film layer  306 , from anode current collector  310 . In an embodiment, dielectric  312  is absent, and the facing surfaces of anode layer  202  touch each other, thereby completely filling at least a portion of gap  206  between adjacent cathode subregions  204 . That is, apposing surfaces of anode layer  202  may touch along a bottom half of gap  206 , completely filling the space between cathode subregions  204  in that lower portion, while the apposing surfaces of anode layer  202  may be separated by dielectric  312  along a top half of gap  206 , in the same manner shown across the entire gap  206  in  FIG. 3 . Thus, the one or more gaps  206  may provide a physical and electrochemical separation between adjacent cathode subregions  204 . Furthermore, the portions of anode layer  202  overlying one cathode subregion  204  may be physically separated from anode layer  202  overlying an adjacent cathode subregion  204 . However, the anode layer portions overlying the cathode subregions  204  may be sandwiched between the cathode subregions  204  and an anode current collector  310 . 
     Referring to  FIG. 4A , a cross-sectional view, taken about line A-A of  FIG. 2 , of an electrochemical cell having a defect in an electrolyte layer over a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, the electrolyte layer  302  may include a defect. The defect may include, for example, a void  402  such as a nano-crack, a micro-crack, or a pinhole. The void  402  may occur in the electrolyte layer  302  during cell fabrication or cell operation. Various causes for the void  402  include suboptimal morphology or cleanliness of any of the cathode current collector  308 , the barrier film layer  306 , the cathode layer  304 , or the electrolyte layer  302 . Furthermore, external short-circuiting, mechanical abuse, thermal abuse, etc., may generate the void  402 . In any case, the void  402  can introduce a path for an electrical leak between the anode layer  202  and the cathode layer  304 . That is, an anode leak  404  may occur as the anode layer  202  material creeps into a cathode subregion  204  of the cathode layer  304 , through the void  402 . As the anode material interacts with the cathode material, chemical reactions  406  may propagate through the cathode subregion  204  to create unwanted chemical products that degrade electrochemical cell function. 
     Referring to  FIG. 4B , a cross-sectional view, taken about line A-A of  FIG. 2 , of an electrochemical cell having a defect in an electrolyte layer over a subdivided cathode layer is shown in accordance with an embodiment. As the anode leak  404  persists, chemical reactions  406  through the cathode subregion  204  may continue and be accompanied by concomitant disappearance of the anode layer  202  over the cathode subregion  204 , as shown in this figure. That is, anode layer  202  material may physically leak through the void  402  until there is no longer anode material directly above void  402 . Accordingly, portions of the anode layer  202  may remain within the one or more gaps  206  between cathode subregions  204 , but there may be an empty space  408  created in a portion of the anode layer  202  that is above the electrolyte layer  302 , e.g., between the electrolyte layer  302  and the anode current collector  310 . Thus, the anode leak  404  may eventually cease, and as a result, the chemical reaction  406  in the cathode subregion  204  may stop. 
     Referring to  FIG. 5 , a plan view of an electrochemical cell having a neutralized cathode subregion is shown in accordance with an embodiment. In an embodiment, after the anode layer  202  has leaked into the cathode subregion  204  through the void  402 , the cathode subregion  204  may be disabled, as shown by cross-hatching in  FIG. 5 . The one or more gaps  206  that are around the disabled cathode subregion  502  will limit the propagation of the anode material and arrest the chemical reaction  406  from expanding into adjacent cathode subregions  204 . Furthermore, the empty space  408  essentially creates an open circuit between the anode current collector  310  and the disabled cathode subregion  502 . Thus, since the cathode subregions  204  are essentially connected in parallel, the empty space  408  reduces the likelihood of healthy cathode subregions  204  from discharging through the unhealthy cathode subregion  502 , i.e., the empty space  408  disconnects the void  402  from the remainder of the operational electrochemical cell  200 . 
     Referring to  FIG. 6 , a side view of an electrochemical cell having a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, the cathode layer  304  includes separate cathode subregions  204  separated by one or more gaps  206  that are filled entirely by a single dielectric, e.g., a gas such as an inert gas, or a vacuum. For instance, an electrochemical cell  200  may be fabricated having essentially flat thin layers that include, the anode layer  202 , the electrolyte layer  302 , the cathode layer  304 , the barrier film layer  306 , and the cathode current collector  308 . An ablation laser may then be used to laser scribe the one or more gaps  206  through the anode layer  202 , the electrolyte layer  302 , and the cathode layer  304 . Alternatively, the one or more gaps  206  may be formed in one or more of the anode layer  202 , the electrolyte layer  302 , and the cathode layer  304  using masking techniques to control the areas of material deposition during fabrication of the electrochemical cell  200 . A thin layer of material may be removed from barrier film layer  506  as well, e.g., using a laser ablation process, such that adjacent cathode subregions  204  are fully separated across gaps  206 . As a result, several cathode subregions  204  separated by one or more gaps  206  may be formed. Similarly, the electrolyte layer  302  and the anode layer  202  may have respective subregions formed therein, separated by the one or more gaps  206 . That is, rather than having a continuous layer structure as described above with respect to  FIG. 3 , anode layer  202  and/or electrolyte layer  302  may be patterned to have a discontinuous layer structure with several subregions formed therein. The discontinuous layer structure may be planar. That is, the subregions of the anode layer  202  and/or electrolyte layer  302  may be essentially coplanar such that sidewalls of the several subregions of each layer face each other across the one or more gaps  206  and respective upward/facing surfaces of the several subregions lie within a common transverse plane. Thus, the electrochemical cell  200  may include several cell subregions  602  physically separated from each other by the one or more gaps  206 . More particularly, each cell subregion  602  may include a stack of cathode, electrolyte, and anode subregions. Furthermore, an anode current collector  310  may be placed over the anode subregions to electrically connect each and all of the cell subregions  602  so as to form a single cell. In an embodiment, the anode current collector  310  has a continuous layer structure, e.g., a single sheet or film structure. Thus, anode subregions may be electrically connected to each other through the continuous layer structure of the anode current collector  310 . In an embodiment, the combined projected surface area of the cell subregions  602  may be at least 80% of the total projected surface area of the electrochemical cell  200  within the electrochemical cell perimeter  208 , i.e., the patterned cathode utilization area may be at least 80%. 
     The electrolyte layer  302  in a cell subregion  602  may develop a void  402  during manufacture or use. In such case, the anode layer  202  in the defective cell subregion  602  may leak through the void  402  into an underlying cathode subregion  204  in the defective cell subregion  602 . As described above, the anode leak  404  may persist until the anode layer  202  over the void  402  is reduced to a point that an empty space  408  is created between the void  402  and the anode current collector  310 . The empty space  408  may provide an electrical open circuit to reduce the likelihood of the discharge of surrounding cell subregions  602  through the defective cell subregion  602 . Furthermore, since the cathode subregion  204  of each cell subregion  602  are physically separated by one or more gaps  206 , the leaking anode layer  202  material may be arrested within the defective cell subregion  602  and disallowed from propagating to other cell subregions  602 . Accordingly, the negative effects of an anode leak  404  may be limited to the disablement of a single cell subregion  602 . 
     Referring to  FIG. 7 , a plan view of an electrochemical cell having a subdivided cathode layer and an anode current collector tab is shown in accordance with an embodiment. In an embodiment, the anode layer  202  of the electrochemical cell  200  may also be an anode current collector. For example, the anode layer  202  may be metallic lithium with sufficient conductivity to act as a current collector across the entire face of the electrochemical cell  200 . Thus, a separate anode current collector  310  over the anode layer  202  may be unnecessary. Accordingly, the anode layer  202  may be used to electrically connect the electrochemically active portions of the electrochemical cell  200  with external product circuitry. For example, the anode layer  202  may be lithium that is conductively connected with external product circuitry through a separate anode current collector tab  702 . The anode layer  202  may conduct electricity between electrochemically active regions of electrochemical cell  200  and the anode current collector tab  702 . The anode current collector tab  702  may, for example, be located in a corner of the electrochemical cell  200 . A region over which the anode current collector tab  702  is coupled with the anode layer  202  may not have a cathode subregion  204 , and thus, may be thinner than a portion of the electrochemical cell  200  that includes a cathode subregion  204 . More particularly, in an embodiment, the thinner corner may be formed by laser ablating or shadow masking the corner during formation of the cathode layer  304 . Subsequently, the electrolyte layer  302  and the anode layer  202  may be deposited over the thinner corner. As a result, the anode current collector tab  702  may be an electrically conductive metal foil having a thickness equal to the thickness of the cathode subregions  204  without adding to an overall height of the electrochemical cell  200 . Thus, incorporating an anode current collector tab  702  in a corner of the electrochemical cell  200  rather than placing an anode current collector  310  over the entire anode layer  202  may result in higher total energy densities of fully packaged electrochemical cells  200  and/or electrochemical devices incorporating electrochemical cells  200 . Furthermore, the anode current collector tab  702  that is electrically connected to the anode layer  202  may be made thicker and more robust to improve the reliability of electrical connections to external circuitry. 
     Referring to  FIG. 8A , a cross-sectional view of an electrochemical device having a defect in an electrolyte layer over a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, an electrochemical device  800  includes a first electrochemical cell  802  stacked on a second electrochemical cell  804  such that respective anode layers  202  of the electrochemical cells are adjacent to or in contact with one another. The respective anode layers  202  may have continuous layer structures, e.g., continuous sheet or film structures, that cover cathode subregions  204  and extend into the one or more gaps  206  between adjacent cathode subregions  204 . Furthermore, as described above, a region of one or more of the stacked electrochemical cells, such as a corner region, may not include a cathode subregion. Thus, a tab insertion space  806  between respective anode layers  202  may allow for insertion of the anode current collector tab  702 . The continuous layer structures of the anode layers  202  may separate the tab insertion space  806  from respective cathode current collectors  308  of the first electrochemical cell  802  and the second electrochemical cell  804 . Thus, the anode current collector tab  702  may be sandwiched between the anode layers  202  and electrically connected to the anode layers  202  within the tab insertion space  806  without contacting cathode current collectors  308 . Anode current collector tab  702  may be bonded to anode layers  202  using, e.g., conductive pressure sensitive adhesive. As described above, a defect such as the void  402  may occur in an electrolyte layer  302 , allowing for an anode leak  404  of the anode layer  202  material into the cathode subregion  204 . 
     Referring to  FIG. 8B , a cross-sectional view of an electrochemical device having a defect in an electrolyte layer over a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, since the respective anode layers  202  are in contact adjacent to the void  402 , the anode leak  404  may include material from anode layers  202  of both the first electrochemical cell  802  and the second electrochemical cell  804  propagating through the void  402  to the affected cathode subregion  204 . As described above in relation to an electrochemical cell  200 , the chemical reaction  406  in the cathode subregion  204  may persist until the empty space  408  is formed over the void  402 . That is, the anode leak may stop after the anode material between electrolyte layers of the electrochemical cells is drained. Accordingly, the electrochemical device  800  having stacked electrochemical cells with subdivided cathode layers may limit defects to individual cathode subregions  204  that become physically and electrically isolated from other portions of the electrochemical device  800 . As such, a defective area may have little impact on the device performance, e.g., capacity, energy, power, resistance, cycle life, and yields and overall performance of the electrochemical device  800  may be improved. 
     Referring to  FIG. 9 , a cross-sectional view of an electrochemical device having an intermediate layer between subdivided cathode layers is shown in accordance with an embodiment. In an embodiment, the propagation of anode layer  202  material when a void  402  occurs may be limited further by incorporating an intermediate layer  902  between respective anode layers  202  of the stacked electrochemical cells in the electrochemical device  800 . For example, the intermediate layer  902  may include an electrically conductive anode current collector between the anode layers  202  that electrically connects the cathode subregions  204  of the electrochemical device  800 , but reduces the likelihood of anode layer  202  material of a second electrochemical cell  804  from propagating through a void  402  in an electrolyte layer  302  of the first electrochemical cell  802 . Thus, when the void  402  forms, anode layer  202  material from the first electrochemical cell  802  may propagate through the void  402  to cause chemical reactions in the cathode subregion  204  until an empty space is formed between the intermediate layer  902  and the void  402 , thereby creating an open circuit and isolating the cathode subregion  204  from the remainder of the electrochemical device  800 . Although the anode current collector tab  702  is illustrated in  FIG. 9 , in an embodiment, intermediate layer  902  may be an anode current collector  310  that extends outside and away from electrochemical device  800  for connection with external product circuitry. Thus, the anode current collector tab  702  may be omitted in an embodiment in which it is a redundant with the intermediate layer  902 . 
     In an alternative embodiment, the intermediate layer  902  may include an insulating layer between the anode layers  202  of the stacked electrochemical cells. For example, the insulating layer  902  may be a thin film of insulating material that is inert to lithium. Examples of such material include pressure sensitive adhesives, such as acrylics, as well as other insulating materials such as polyimide, etc. The insulating layer may be one or both of electrically insulating or ionically insulating, and may be made from materials having either of those properties. 
     Referring to  FIG. 10 , a plan view of an electrochemical cell having a subdivided anode layer is shown in accordance with an embodiment. An electrochemical cell  200  may include an anode layer  202  over a cathode layer. Furthermore, the anode layer  202  may be subdivided into one or more anode subregions  1002  spaced across the electrochemical cell  200  above the cathode layer and the electrolyte layer. More particularly, the anode subregions  1002  may be separated from each other by one or more gaps  206 . For example, one or more gaps  206  may surround each anode subregion  1002  to physically isolate the anode subregion  1002  from neighboring anode subregions  1002 . 
     In an embodiment, the anode layer  202  may include a grid pattern, in which each anode subregion  1002  includes a rectangular surface area and is separated from adjacent anode subregions  1002  by one or more linear gaps  206  traversing the electrochemical cell  200 . After anode layer material is deposited over the electrolyte layer, laser scribing may be used to remove the anode layer material to form one or more gaps  206  between anode subregions  1002 . Alternatively, shadow masking may be used to form anode subregions  1002  separated by masked regions that become the unfilled gaps  206 . However, other anode layer  202  patterns may be used. For example, the one or more gaps  206  may be laser scribed in any shape to form anode subregions  1002  that are, e.g., polygonal, conic sections, elliptical, etc. The remaining anode material of the anode subregions  1002  essentially form islands of a patterned anode layer  202 . Anode subregions  1002  may have a same or different shape as compared to other anode subregions  1002  in the anode layer  202 . 
     Regardless of the shape of the anode subregions  1002 , the anode layer  202  may include a total projected surface area when viewed from above within an electrochemical cell perimeter  208  that includes a combined projected surface area of each anode subregion  1002  and a combined projected surface area of the one or more gaps  206  between the anode subregions  1002 . For example, each anode subregion  1002  may have a projected area of a square profile with equal sides and each gap  206  may have equal widths. Thus, a total projected surface area of the anode layer  202  within an electrochemical cell perimeter  208  may include all of the projected square anode subregion surface areas as well as the projected surface area within the uniform gaps  206 . In an embodiment, a patterned anode area utilization, i.e., a ratio of the combined individual anode subregion surface areas to the total surface area of the anode layer  202 , may be less than 30%. For example, the patterned anode area utilization may be less than 25%. In an embodiment, a grid pattern has square anode subregions  1002  with sides of 10 micron separated by one or more 10 micron gaps  206 . Thus, the patterned anode area utilization may be expected to be 25%. Widening the one or more gaps  206  or shrinking the anode subregions  1002  can decrease the patterned anode area utilization. 
     Referring to  FIG. 11 , a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a subdivided anode layer is shown in accordance with an embodiment. In an embodiment, the electrochemical cell  200  may include the electrolyte layer  302  between the anode layer  202 , having anode subregions  1002  and one or more gaps  206 , and the cathode layer  304 . As described above, the one or more gaps  206  in the anode layer  202  may define a space between the portions of the anode layer  202  that contain anode material such as lithium, i.e., a space between anode subregions  1002 . Gaps  206  may be formed by removing anode material and optionally a thin layer of electrolyte material using, e.g., a laser ablation process. Thus, the anode subregions  1002  may be fully separated by intervening gaps  206 . In an embodiment, the gaps  206  between the anode subregions  1002  of the anode layer  202  are filled entirely by a single dielectric  312 , e.g., a dielectric gas such as an inert gas, or a vacuum. Furthermore, the barrier film layer  306  may be between the cathode layer  304  and the cathode current collector  308 . In an embodiment, the electrochemical cell  200  may include the electrically conductive anode current collector  310  placed in electrical contact with the anode layer  202 . The anode current collector  310  may include a metal foil that makes mechanical and electrical contact with all of the anode subregions  1002  of the anode layer  202 . In an embodiment, the various layers of electrochemical cell  200  may include materials and dimensions similar to those described above with respect to the electrochemical cell  200  having a patterned cathode layer  304 . 
     Referring to  FIG. 12 , a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a defect in an electrolyte layer under a subdivided anode layer is shown in accordance with an embodiment. In an embodiment, the electrolyte layer  302  may include a defect, such as a void  402 . As described above, the void  402  can introduce a path for an electrical leak between the anode layer  202  and the cathode layer  304 . However, as compared to an electrochemical cell  200  having a uniform, i.e., non-patterned anode layer  202  across electrochemical cell  200 , the electrochemical cell  200  having anode subregions  1002  occupying only a fraction of the total projected surface area of the anode layer is less likely to have the void  402  aligned with an anode subregion  1002 . More particularly, the void  402  may be three times more likely to be aligned with the one or more gaps  206  when the combined projected surface areas of the anode subregions  1002  is only 25% of a total projected surface of the anode layer  202 . Thus, as a result of the patterned anode layer  202 , the likelihood of battery failure via internal short circuit between the anode subregions  1002  and the cathode layer  304  may be reduced in proportion to the patterned anode area utilization. 
     Referring to  FIG. 13A , a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a defect in an electrolyte layer under a subdivided anode layer is shown in accordance with an embodiment. In an embodiment, the void  402  may occur in the electrolyte layer  302  between an anode subregion  1002  and the underlying cathode layer  304 . Thus, the void  402  can introduce a path for an electrical leak between the anode layer  202  and the cathode layer  304 . That is, an anode leak  404  may occur as the anode layer material creeps into the cathode layer  304  through the void  402 . As the anode material interacts with the cathode material, chemical reactions  406  may propagate through the cathode layer  304  to create unwanted chemical products. Furthermore, electron discharge from neighboring anode subregions  1002  may follow a pathway  1302  through the anode current collector  310  into the anode subregion  1002  adjacent to the void  402 , and then onward through the void  402  into the cathode layer  304 . Accordingly, the void  402  may result in self-discharge of the anode layer  202  that could eventually discharge the entire electrochemical cell  200 . 
     Referring to  FIG. 13B , a cross-sectional view, taken about line C-C of  FIG. 10 , of an electrochemical cell having a defect in an electrolyte layer under a subdivided anode layer is shown in accordance with an embodiment. As the anode leak persists, chemical reactions in the cathode layer  304  may continue and be accompanied by concomitant disappearance of the anode subregion  1002  adjacent to the void  402 . That is, anode layer material may physically leak through the void  402  until there is no longer anode material above void  402 . Accordingly, an empty space  408  may be created above the void  402 , e.g., between the electrolyte layer  302  and the anode current collector  310 . The empty space  408  may create an electrical open circuit between the electrolyte layer  302  and the anode current collector  310 . Thus, the anode leak may eventually cease, and the chemical reaction and electrical leakage in the cathode layer  304  may stop. In an embodiment, the anode leak may result in a degraded region  1304  of the cathode layer  304 , but a larger healthy region of the cathode layer  304  may be unaffected by the anode leak. Thus, a patterned anode layer may mitigate the impact of an electrolyte layer defect on overall performance of the electrochemical cell  200 . 
     Referring to  FIG. 14 , a side view of an electrochemical device having an anode current collector between subdivided anode layers is shown in accordance with an embodiment. In an embodiment, an electrochemical device  800  may be formed from several electrochemical cells  200  having patterned anode layers as described with respect to  FIG. 10 . More particularly, several electrochemical cells  200  may be stacked with respective anode subregions  1002  facing one another. Some of the anode subregions  1002  in the anode layers may be directly across from the anode current collector  310  from one another, i.e., may appear overlapping when viewed from above (i.e., when viewed vertically downward along the plane of the drawing sheet). The anode current collector  310  may have a continuous layer structure, e.g., a continuous sheet or film structure. Thus, the anode subregions  1002  of respective stacked electrochemical cells  200  may be electrically connected to each other through the continuous layer structure of the anode current collector  310 . That is, the anode subregions  1002  of a first electrochemical cell  200  of electrochemical device  800  may be electrically connected with each other, as well as electrically connected with anode subregions  1002  of a second electrochemical cell  200  of electrochemical device  800 , through the continuous layer structure of the anode current collector  310 . Furthermore, the anode current collector  310  having a continuous layer structure may be between respective cathode layers  304  of the stacked electrochemical cells  200  of electrochemical device  800 , thereby physically separating the electrochemical cells  200 . 
     In an embodiment, one or more of the stacked electrochemical cells  200  forming electrochemical device  800  may include a cathode current collector  308  electrically connected to a cathode layer  304 . For example, a first cathode current collector  308  may be electrically connected to a cathode layer  304  of a first electrochemical cell  200  of electrochemical device  800  and a second cathode current collector  308  may be electrically connected to a cathode layer  304  of a second electrochemical cell  200  of electrochemical device  800 . Both the cathode layer  304  and the cathode current collector  308  may have continuous layer structures, e.g., continuous sheet or film structures. 
     In an embodiment, the electrochemical device  800  may include a void  402  in one of the electrolyte layers  302  that causes an anode leak  404  to reduce the size of a respective anode subregion  1002  adjacent to the void  402 . Accordingly, the anode subregion  1002  will eventually shrink to fill space laterally away from void  402  (not under void  402 ), as indicated by the dotted lines in  FIG. 14 , to result in an empty space between the void  402  and the anode current collector  310 . Thus, the degraded region  1304  of the underlying cathode layer  304  may be limited by the size of the anode subregion  1002  adjacent to the void  402 . As such, an electrochemical device having patterned anode layers may limit the impact that an electrolyte void has on overall performance of the device. 
     Referring to  FIG. 15 , a plan view of an electrochemical cell having a subdivided anode layer over a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, electrochemical cell  200  may be subdivided into several cell subunits  1500 , and each cell subunit may include at least two anode subregions  1002  disposed over a cathode subregion  204 . That is, the anode layer  202  may be subdivided into one or more anode subregions  1002  spaced across the electrochemical cell  200  above a cathode layer  304  that is also subdivided into one or more cathode subregions  204 . For example, as shown in  FIG. 15 , each cathode subregion  204  may provide a base to support four anode subregions  1002 , although this is illustrated by way of example and not limitation. More particularly, the cathode layer  304  may be patterned to include at least two cathode subregions  204 , and two or more of the anode subregions  1002  may be disposed over one of the cathode subregions  204  represented with hidden lines. In each of the cathode layer  304  and the anode layer  202 , one or more gaps may surround each patterned island. For example, one or more gaps  1502 A may separate anode subregions  1002  from neighboring anode subregions  1002 , and one or more gaps  1502 B may separate cathode subregions  602  from a neighboring cathode subregions  602 . Accordingly, the gaps  1502 B may also extend into the page between cell subunits  1500  to separate the cell subunits. As described above, the gaps  1502 A and  1502 B may be at least partially filled by a dielectric  312 , e.g., a dielectric gas. 
     Referring to  FIG. 16 , a cross-sectional view, taken about line D-D of  FIG. 15 , of an electrochemical cell having a subdivided anode layer over a subdivided cathode layer is shown in accordance with an embodiment. In an embodiment, the electrochemical cell  200  may include the electrolyte layer  302  between the anode layer  202 , having anode subregions  1002  and one or more gaps  1502 A, and the cathode layer  304 , having cathode subregions  204  and one or more gaps  1502 B. As described above, the one or more gaps  1502 A in the anode layer  202  may define a space between the anode subregions  1002 . Anode subregions  1002  may contain anode material such as lithium. In an embodiment, the one or more gaps  1502 A are filled entirely by a single dielectric  312 , e.g., a dielectric gas such as an inert gas, or a vacuum. Also as described above, the one or more gaps  1502 B in the cathode layer  304  may define a space between the cathode subregions  204  (and also separate anode subregions  1002  located on adjacent cathode subregions  204 ). The cathode subregions may contain cathode material. In an embodiment, the one or more gaps  1502 B are filled entirely by a single dielectric  312 , e.g., a dielectric gas such as an inert gas, or a vacuum. In an embodiment, the electrochemical cell  200  may include the electrically conductive anode current collector  310  placed in electrical contact with anode subregions  1002 . The anode current collector  310  may include a metal foil that makes mechanical and electrical contact with all of the anode subregions  1002  in the electrochemical cell  200 . Furthermore, the electrochemical cell  200  may include an electrically conductive cathode current collector  308  placed in electrical connection with the cathode subregions  204 . That is, the cathode subregions  204  may electrically connect to a common, or shared, cathode current collector  308 . The various layers of electrochemical cell  200  may include materials and dimensions similar to those described above. 
     In an embodiment, the anode layer  202  and the cathode layer  304  may each include a grid pattern, as described above. In an embodiment, the anode layer  202 , the cathode layer  304 , and the electrolyte layer  302  may be formed over, e.g., cathode current collector  310 , in uniform layers. The layers may then be selectively laser scribed to create one or more gaps  1502 B separating cathode subregions  204  (and also separating anode subregions  1002  located on adjacent cathode subregions  204 ) and one or more gaps  1502 A separating anode subregions  1002  on top of one or more of cathode subregions  204 . More particularly, laser scribing may remove material to create essentially a set of cathode islands with a set of anode islands over one of the cathode islands. Other methods, including shadow masking may be used to form the structure shown in  FIG. 16 . 
     Referring to  FIG. 17 , a flowchart illustrating a method for isolating a cathode layer from an anode leak is shown in accordance with an embodiment. At operation  1702 , during production of an electrochemical cell  200  or assembly of an electrochemical device  800 , such as a solid-state battery, a void  402  in an electrolyte layer  302  may be detected. Detection of the void  402  may occur at various times during the manufacturing process, including before or after deposition of the anode layer  202  over the electrolyte layer  302 . At operation  1704 , once the void  402  is detected, various operations may be employed to ensure that the cathode layer  304  in a finished electrochemical cell  200  will be isolated from the anode layer  202  across the electrolyte layer  302 . For example, the void  402  may be filled or the anode layer material may be removed from over the void  402  to reduce the likelihood of an anode leak  404 . Embodiments of methods for detecting a void  402  and isolating the cathode layer  304  will be described further below. 
     Referring to  FIG. 18 , a side view of an electrochemical cell during a defect detection operation is shown in accordance with an embodiment. Detection of the void  402  at operation  1702  may include detection performed by optical, electrical, thermal, and other testing methods that are known for finding material voids. For example, an electrochemical cell  200  may be viewed under microscopy to detect the void  402 . In an embodiment, the void  402  in electrolyte layer  302  causes a depression  1802  in an anode subregion  1002  of the anode layer  202 , as the anode layer material creeps into the void  402 . The depression  1802  may be visible as a discoloration or as a defective topology, such as a sinkhole on a top surface of an anode subregion  1002 . Thus, the void  402  may be identified by optical methods. 
     In an embodiment, the void  402  may be detected with electrical methods. For example, the anode layer  202  may include several anode subregions  1002  over a top surface of the electrochemical cell  200 . Depending on the integrity of the electrolyte layer  302  beneath the anode subregions  1002 , the voltage at the anode subregions  1002  may vary. For example, a voltage probe may be placed on the rightmost anode subregion  1002  shown in  FIG. 18  to measure a first voltage measurement and the center anode subregion  1002  may be probed to measure a second voltage measurement. In an embodiment, given that the void  402  may create an electrical short between the center anode subregion  1002  and the cathode layer  304 , the first voltage measurement may be markedly higher than the second voltage measurement. It may therefore be inferred through voltage readings of a patterned anode layer which anode subregions  1002  are adjacent to voids  402 . Thus, in addition to increasing yield and mitigating the impact of defects on cell performance, an electrochemical cell  200  having a patterned anode layer  202  may also facilitate identification of defects during manufacturing, so that they may be dealt with prior to product packaging. This may increase yields and product performance even further. 
     Additional methods of detecting voids  402  may be used. For example, electrical methods of detection may also include measuring current flow or resistivity across the electrochemical cell  200  to infer a void  402  location. Thermal methods of detection include monitoring surface temperatures of electrochemical cell  200  while applying a current to infer void  402  locations through the identification of localized hot spots. Other methods include electromagnetic wave deflection, absorption, reflection, raman scattering, etc., that can be used to detect pinholes in materials, i.e., the void  402  in electrolyte layer  302 . Depending upon the stage of manufacturing at which the void  402  is detected, various methods may be used to mitigate the impact of the void  402  by isolating the cathode layer  304  under the void  402 . In particular, modifications may be made to ensure that in the final electrochemical cell  200  assembly, the cathode layer  304  under the void  402  is either not in electrical communication with the anode layer  202 , or is isolated from surrounding cathode layer  304  areas to mitigate the impact that an anode leak  404  may have on electrochemical cell function. 
     Referring to  FIG. 19 , a side view of a precursor cell having a defect in an electrolyte layer is shown in accordance with an embodiment. A precursor cell  1900  may include the electrolyte layer  302 , the cathode layer  304 , the barrier film layer  306 , and the cathode current collector  308 . Thus, in an embodiment, the precursor cell  1900  represents a state of manufacturing prior to deposition of the anode layer  202  over the electrolyte layer  302 . At this stage, a void  402  may be detected in the electrolyte layer  302  using any of the methods described above, or other detection methods. Accordingly, a repair technique may be employed that will reduce the likelihood of an anode leak  404  through the void  402  after the anode layer  202  is deposited over the electrolyte layer  302 . 
     Referring to  FIG. 20 , a side view of an electrochemical cell having a backfilled electrolyte layer is shown in accordance with an embodiment. In an embodiment, the void  402  detected in the precursor cell  1900  may be filled with a filler  2002 . For example, the void  402  may be ablated, drilled, ground, etc., to form a bore  2004  through the electrolyte layer  302 . The bore  2004  may enlarge the void in electrolyte layer  302 , making it easier to insert a filler material. Furthermore, although the bore  2004  may be controlled to stop at an upper surface of the cathode layer  304 , in an embodiment, the bore  2004  may extend into the cathode layer  304 . After creating bore  2004 , a filler material may be backfilled into the bore  2004 . Thus, when the anode layer  202  is deposited in a subsequent operation, the cathode layer  304  may be electrically isolated from the anode layer  202  across filler  2002 . Accordingly, the filler  2002  may include a variety of materials that may be inert to lithium, and which may be electrically insulating. The choice of materials may include adhesive materials that can be injected into the bore  2004  and then allowed to cure under, e.g., time, heat, and/or ultraviolet radiation. 
     Referring to  FIG. 21 , a side view of an electrochemical cell having a defect in an electrolyte layer is shown in accordance with an embodiment. In an embodiment, the void  402  in the electrolyte layer  302  may be detected after deposition of the anode layer  202 . For example, one of the detection methods described above may be used to detect the void  402  prior to placing an anode current collector  310  over the anode layer  202 . In an embodiment, the anode layer may be patterned to facilitate detection using voltage probing, as described above. Accordingly, a repair technique may be employed that isolates the cathode layer  304  from an anode leak  404  through the void  402 . 
     Referring to  FIG. 22A , a side view of an electrochemical cell having a cathode layer isolated from an anode leak is shown in accordance with an embodiment. In an embodiment, the anode layer  202  over the void  402  may be removed such that the void  402  does not extend from the anode layer  202  to the cathode layer  304 . That is, the anode material is removed over a first end of the void  402 , is not present above void  402 , and thus cannot leak through the void. Accordingly, an anode leak  404  through the void  402  may not be established, and thus, the impact of void  402  on electrochemical cell  200  performance may be mitigated. Removal of the anode layer  202  may include forming a blind hole  2202  over the void  402 . An inner dimension of the blind hole  2202  may be at least as large as the void  402  diameter and the bottom of the blind hole  2202  may terminate at or below an upper surface of the electrolyte layer  302 . Accordingly, the repaired electrochemical cell  200  may have no anode layer  202  material adjacent to the void  402 , and the risk of an anode leak  404  occurring may therefore be reduced. 
     Referring to  FIG. 22B , a side view of an electrochemical cell having a cathode layer isolated from an anode leak is shown in accordance with an embodiment. In an embodiment, the anode layer  202  and the void  402  may be removed to isolate the cathode layer  304  from the anode layer  202 . More particularly, a blind hole  2202  may be formed through the anode layer  202  and the electrolyte layer  302  to remove the void  402 . A sidewall  2204  of the blind hole  2202  may be contiguous such that each layer along the sidewall  2204  is electrically isolated and essentially continuous with one another, e.g., as in having a tapered sidewall  2204 . That is, although the sidewalls  2204  of the anode layer  202  and the electrolyte layer  302  may be essentially continuous with one another, the anode layer  202  may be sufficiently isolated from the cathode layer  304  to reduce the likelihood of anode layer  202  material from electrically shorting with the cathode layer  304 . Accordingly, the repaired electrochemical cell  200  may reduce the risk of an anode leak  404  occurring in an assembled solid-state battery. 
     Referring to  FIG. 22C , a side view of an electrochemical cell having a cathode layer isolated from an anode leak is shown in accordance with an embodiment. In an embodiment, rather than removing the anode layer  202  adjacent to the void  402 , a portion of the cathode layer  304  may be isolated from the rest of the cathode layer  304  so that if an anode leak  404  occurs, the degraded region will be limited to a small fraction of the cathode layer  304 . Thus, the impact on electrochemical cell performance may be reduced. In an embodiment, a channel  2206  may be formed around the void  402  to isolate a first cathode portion  2208  from a second cathode portion  2210 . The channel  2206  may be annular having an inner wall that includes the first cathode portion  2208  sidewall and an outer wall that includes the second cathode portion  2210  sidewall. Furthermore, the channel  2206  may extend from an upper surface of the electrochemical cell  200  or precursor cell  1900  to the barrier film layer  306  (and may even extend below the top surface of barrier film layer  306  supporting cathode layer  304 ). Thus, the channel  2206  may create a discontinuity to physically isolate the cathode portions from each other. In an embodiment, the channel  2206  may be backfilled with, e.g., a dielectric filler, to further isolate the cathode portions physically, electrically, or ionically. Although an anode leak  404  may form between the anode layer  202  and the first cathode portion  2208 , the first cathode portion  2208  volume may be small so as to cause the entire portion to chemically react and to then cease to support further propagation of the chemical reaction to nearby areas of the cathode layer  304 . Accordingly, the repaired electrochemical cell  200  may reduce the impact of an anode leak  404  on electrochemical cell  200  performance. 
     The various repair modifications described above with respect to isolating the cathode layer  304  may be made using a variety of fabrication technologies. For example, a bore  2004 , a blind hole  2202 , or a channel  2206  may be formed through one or more layers of the electrochemical cell  200  using, e.g., laser machining techniques such as laser ablation, abrasive jet machining, etching, etc. Some of these processes, such as laser ablation, can remove portions of material layers, such as a thin top layer from barrier film layer  306 , without melting and cutting through the entire material thickness, as is typically the case with conventional laser cutting processes. Furthermore, modifications that involve the addition of materials, such as backfilling the bore  2004  with the filler  2002 , may be performed using material application techniques such as coating, infusion, deposition, etc. Accordingly, the impact of electrolyte layer defects on product cost and performance may be mitigated by detecting and repairing the defects. 
     The present invention also provides the following itemized embodiments: 
     1. An electrochemical cell, comprising: an electrolyte layer between an anode layer and a cathode layer, wherein the electrolyte layer includes a hole at least partially filled by a filler, and wherein the filler separates the anode layer from the cathode layer. 
     2. An electrochemical cell, comprising: an electrolyte layer between an anode layer and a cathode layer, wherein the electrolyte layer includes a void extending from a first end to the cathode layer, and wherein the anode layer includes a hole over the void such that the hole separates the void from the anode layer. 
     3. An electrochemical cell, comprising: an electrolyte layer between an anode layer and a cathode layer, wherein the electrolyte layer includes a void; and a channel extending through the electrolyte layer and the cathode layer around the void, such that a first region of the cathode layer is separated from a second region of the cathode layer by the channel. 
     4. A method, comprising: detecting a void in an electrolyte layer, wherein the void extends from a first end to a cathode layer of an electrochemical cell; and isolating the cathode layer from the first end. 
     5. The method of item  4 , wherein the electrolyte layer is between the cathode layer and an anode layer, and wherein detecting the void includes measuring an electrical voltage at one or more anode subregions of the anode layer. 
     6. The method of item  4 , wherein isolating the cathode layer includes filling the void with a filler to separate the cathode layer from the first end. 
     7. The method of item  4  further comprising depositing an anode layer over the electrolyte layer such that the void extends from the anode layer to the cathode layer, and wherein isolating the cathode layer includes removing the anode layer over the void such that the void does not extend from the anode layer to the cathode layer. 
     8. The method of item  4  further comprising depositing an anode layer over the electrolyte layer such that the void extends from the anode layer to a first region of the cathode layer, and wherein isolating the cathode layer includes forming a channel around the void through the electrolyte layer and the cathode layer, such that the first region of the cathode layer is separated from a second region of the cathode layer by the channel. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Metadata:
Filing Date: 20150526
Publication Date: 20181030
Grant Date: 20181030
Priority Date: 20140527
Inventors: NEUDECKER, Bernd Jurgen
SNYDER, Shawn William
ISHIKAWA, TETSUYA
ANDERSON, Tor Collins
Assignee: APPLE INC
CPC Classifications: [{"code": "H01M10/0562", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M6/40", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/052", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/058", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M6/40", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M10/0585", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/058", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0562", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0562", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0436", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/052", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0585", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0585", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0436", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/058", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M6/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/052", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/052", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M10/0562", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M6/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/409", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0585", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0436", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02P70/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M2/164", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0463", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/0436", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M10/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01M10/052", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M6/40", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0585", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0562", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/058", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M2004/021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M50/409", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02P70/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M50/409", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01M50/409", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02E60/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02E60/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01M10/0436", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 53284643