Patent Application
20220328860
This application relates to solid-state batteries, and in particular to ceramic solid-state batteries including piezoelectric layers configured to compensate for material changes during operation thereof.
Batteries with lithium metal anodes provide a high energy density among currently commercially available batteries. While the reduction/oxidation reactions that liberate the energy from the lithium metal chemistry are reversible, rechargeable batteries with lithium metal anodes are not largely commercially available. Such rechargeable batteries may not be largely commercially available because of the potential of fire and explosion that may be caused by the growth of lithium dendrites during the recharge cycle of a solid-state battery. The lithium dendrites that may grow in the anode during the recharge cycle may extend through the solid-state electrolyte, and even through the cathode, and create a short circuit directly between the anode and cathode. Several strategies for preventing shorting dendrites have been advanced with varying degrees of success, but none have yet reached the level of safety required for commercial acceptance. Among some approaches for reducing the fire and explosion risk in advanced LIBs (Lithium Ion Batteries) with lithium metal anodes is the use of solid-state, ceramic electrolyte as the separator between anode and cathode.
During operation of a solid-state battery, both the anode and the cathode may undergo material changes as well as changes in mechanical forces between the various layers of the solid-state battery. These changes may be caused by, e.g., material transport such as Lithium ions, volume changes due to material transport. As a result, the interface between the anode or cathode and the current collector may deteriorate, which may lead to a deterioration in the amount of power being generated or in the recharging ability of the solid-state battery. Typically, to improve the electrical interface between the various layers of a solid-state battery, cell manufacturers apply some amount of mechanical pressure to the battery layers using, e.g., a spring inside a coin cell. For example, higher pressures applied to the various layers typically result in better interfaces between the layers, and thus a better performance of the solid-state battery. Also, to compensate for swelling due to traveling charge carriers such as, e.g., Li ions, new types of anode structures such as, e.g., nano wires, are developed that swell into empty spaces rather than in the direction of the traveling charge carriers.
In one general aspect, the instant application describes a solid-state battery cell that includes a cathode region, an anode region, a separator interconnecting the cathode region and the anode region, the separator including a solid-state electrolyte, a cathode current collector on a surface of the cathode region, an anode current collector on a surface of the anode region, a first piezoelectric layer on a surface of the cathode current collector opposite the cathode region, and a second piezoelectric layer on a surface of the anode current collector opposite the anode region.
The above general aspect may include one or more of the following features. For example, at least one of the first piezoelectric layer and the second piezoelectric layer is powered by a voltage source separate from the solid-state battery cell. For another example, at least one of the first piezoelectric material layer and the second piezoelectric material layer is powered by the solid-state battery cell.
For another example, the solid-state electrolyte includes a ceramic electrolyte. For a further example, at least one of the first piezoelectric material layer and the second piezoelectric material layer include a ceramic material. For example, the ceramic material is a 3D-printed ceramic material.
In another general aspect, the instant application describes a solid-state battery cell that includes a cathode region, a first anode region, a second anode region on an opposite side of the cathode region from the first anode region, a first separator interconnecting the cathode region and the first anode region, the first separator including a first solid-state electrolyte, a second separator interconnecting the cathode region and the second anode region, the second separator including a second solid-state electrolyte, a first anode current collector on a surface of the first anode region, a second anode current collector on a surface of the second anode region, a first piezoelectric layer on a surface of the first anode current collector, and a second piezoelectric layer on a surface of the second anode current collector.
For another example, at least one of the first piezoelectric layer and the second piezoelectric layer is connected to a voltage source. As another example, at least one of the first solid-state electrolyte and the second solid-state electrolyte includes a ceramic electrolyte. For a further example, at least one of the first anode region and the second anode region includes a lithium anode.
In yet another general aspect, the instant application describes a battery that includes a plurality of solid-state cells arranged in a stack, the stack including a first cell at a first end thereof and a last cell at a second end thereof opposite the first end. Each of the plurality of cells includes a cathode region, an anode region, a separator interconnecting the cathode region and the anode region, the separator including a solid-state electrolyte, a cathode current collector on a surface of the cathode region of the first cell, and an anode current collector on a surface of the anode region of the last cell, a first piezoelectric layer on a surface of the cathode current collector, and a second piezoelectric layer on a surface of the anode current collector.
For another example, at least one of the first piezoelectric material layer and the second piezoelectric material layer is connected to a voltage source located inside the battery. For a further example, at least one of the first piezoelectric material layer and the second piezoelectric material layer is connected to one or more of the plurality of solid-state cells. As another example, the battery is encased in a receptacle, and the voltage source is inside the receptacle.
In yet another general aspect, the instant application describes a battery that includes a plurality of solid-state cells arranged in a stack, the stack including a first cell at a first end thereof and a last cell at a second end thereof opposite the first end. Each of the plurality of cells includes a cathode region, a first anode region, a second anode region on an opposite side of the cathode region from the first anode region, a first separator interconnecting the cathode region and the first anode region, the first separator including a first solid-state electrolyte, a second separator interconnecting the cathode region and the second anode region, the second separator including a second solid-state electrolyte, a first anode current collector on a surface of the first anode region of the first cell, a second current collector on a surface of the second anode region of the last cell, a first piezoelectric layer on a surface of the first anode current collector, and a second piezoelectric layer on a surface of the second anode current collector.
In one general aspect, the instant application describes a method of operating a solid-state battery cell that includes detecting a first voltage at one of the first piezoelectric layer and the second piezoelectric layer, and when the first voltage is a non-zero voltage, applying a second voltage to the one of the first piezoelectric layer and the second piezoelectric layer.
For another example, the at least one of the first piezoelectric material layer and the second piezoelectric material layer generate pressure against an adjacent layer due to the applied second voltage. As another example, the applied second voltage is equal to the detected first voltage.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements. Furthermore, it should be understood that the drawings are not necessarily to scale.
In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.
Solid-state batteries present a technical problem where one or both electrodes of a given solid-state battery may undergo material losses during operation of the battery, and the loss of material may impair the quality and performance of the battery. To address these technical problems and more, in various implementations, this description provides a technical solution for solid-state batteries, where a piezoelectric layer is provided on each electrode, and the piezoelectric layer is configured to expand and apply a pressure on an adjacent electrode when electric power is applied to it. The adjacent electrode may undergo, e.g., material changes such as material losses, or other physical degradation during operation of the battery. As a result of the applied pressure, an integrity of the interface between the adjacent electrode and the current collector, or between the adjacent electrode and the solid electrolyte, may be maintained, and the performance of the solid-state battery may be preserved.
An exemplary advanced solid-state cell is illustrated in
In some implementations of the disclosure, each layer of anode materials 40 and cathode materials 10 can mechanically define the anodes and cathodes for two sub-cells 99 of a many layered cell 100. Each of the sub-cells 99 can be separated by a current collector 50. That is, the boundary between the first and second of these sub-cells 99 can be defined by current collector 50. In some implementations, the current collector 50 can include low reactivity metals or metallic compounds, like copper, aluminum, gold, platinum, tin oxide or indium oxide. Other materials can be implemented as a current collector 50 herein.
Alternatively, each sub-cell 99 of the cell 100 can be completely separated from adjacent sub-cells by layers of insulating material. In some implementations, the insulating material can include dielectric material, ceramic materials such as porcelain. Other ceramics can include alumina and zirconia. Other known materials can be implemented as an insulating material herein. Specifically, each sub-cell is a layered structure, made up of two different classes of solid-state electrolyte materials. A layer of low porosity, impenetrable ceramic electrolyte material can function as each cell's separator 30. For example, a separator 30 including a layer of nonporous ceramic electrolyte might successfully be as thin as 10 μm, but a separator including a ceramic electrolyte of 5% porosity might have to be 30 μm thick to avoid penetrating apertures, giving a sub-cell 99 three times more internal series resistance and correspondingly poorer electrical performance. Layers of relatively high but controlled porosity can function specifically as the anode layers 40 and the cathode layers 10. For example, some low porosity ceramic electrolyte material can include lithium aluminum titanium phosphate, lithium aluminum germanium phosphate, lithium lanthanum zirconate garnet (LLZO), LLZO garnet with calcium and niobium substitutions (LLCZN). An anode region 40 or cathode region 10 with 70% porosity would be able to hold twice as much lithium-bearing material as a region having 35% porosity, meaning that for the same total volume, the 70% version would have twice the storage capacity.
In various implementations, during the charging-discharging process of a solid-state battery, the respective thicknesses of the cathode and of the anode increase and decrease as a function of the charging or discharging cycle of the solid-state battery. As a result of these changes in the thicknesses of the cathode and the anode, the battery cell of the solid-state battery may experience swelling because the changes in the thicknesses of the cathode and of the anode are not equivalent in size and do not naturally compensate for each other. The swelling of the solid-state battery that is due to these material changes may be the cause of failure of the solid-state battery.
In various implementations, in order to compensate for the loss of material for the cathode structure during the charging process, the piezoelectric layer 60, under the impetus of an electric voltage source, generates a force or pressure and expands against the cathode current collector 20 and the cathode structure 10. Accordingly, the applied pressure may maintain the quality of the interfaces between several layers of the battery 400: the interface between, e.g., the cathode current collector 20 and the cathode structure 10, the interface between the cathode structure 10 and the solid electrode separator 30, and possibly the interface between the solid electrolyte separator 30 and the anode region 40. As a result of the application of pressure from the piezoelectric layer 60 against the current collector 20, any deleterious effects caused by material losses of the cathode structure 10 on the interface between the layers of the battery 400 may be mitigated, reduced or compensated. Accordingly, the quality of the interface between the layers of the battery 400, e.g., between the cathode structure 10 and the ceramic electrolyte separator 30, may be maintained to ensure a good operation state of the solid-state battery cell 400.
As a result of this change in thickness in the anode region 40, the piezoelectric layer 80, under the impetus of a voltage source, generates a force or pressure and expands against the anode region 40. Accordingly, the applied pressure from the piezoelectric layer 80 may maintain the quality of the interfaces between several layers of the battery 500: the interface between, e.g., the anode current collector 50 and the anode region 40, the interface between the anode region 40 and the solid electrode separator 30, and possibly the interface between the solid electrode separator 30 and the cathode structure 10. As a result of the application of pressure against the current collector 50 by the piezoelectric layer 80, any deleterious effects due to material losses of the anode region 40 on the interface between the layers of the battery 500 may be mitigated, reduced or compensated. Accordingly, the quality of the interface between the layers of the battery 500, e.g., between the anode region 40 and the ceramic electrolyte separator 30, may be maintained to ensure a good operation state of the solid-state battery cell 500.
In various implementations, the piezoelectric layers 80 or 60 may also be used as sensors to sense the extent of the material changes occurring at the cathode structure 10 or at the anode region 40. For example, the pressure applied by either one of the cathode structure 10 or the anode region 40 can be measured via a voltage detected by the piezoelectric layer 80 or 60. Such measurement may be indicative of the material changes occurring at the cathode structure 10 or at the anode region 40. For example, a voltage reading of the piezoelectric layer 80 or 60 may be indicative of a given amount of material change expressed in added pressure or decreased pressure against the piezoelectric layer 80 or 60.
In various implementations, the voltage measured by the piezoelectric layer 80 or 60 may be used to apply the correct amount of pressure to cathode structure 10 or the anode region 40. For example, when a voltage is measured at the piezoelectric layer 80 or 60 as a result of added or reduced pressure from the cathode structure 10 or the anode region 40, substantially the same voltage may be used to apply to the piezoelectric layer 80 or 60 to in turn apply a compensating pressure on the cathode structure 10 or the anode region 40.
Although
In various implementations, the voltage source 710 is connected to the solid-state battery 700 and is powered by the solid-state battery 700. In other implementations (not shown), the voltage source 710 is independent from the solid-state battery 700 and is not electrically connected to the solid-state battery 700.
In various implementations, at S820, as a result of detecting the first voltage, a second voltage is applied to the piezoelectric layer that is on the side of the electrode for which the first voltage has been detected. For example, when the first voltage is detected from the piezoelectric layer 60, the second voltage may be applied to the piezoelectric layer 60 to urge the piezoelectric layer 60 to apply pressure against the cathode structure 10. For example, when the first voltage is detected from the piezoelectric layer 80, the second voltage may be applied to the piezoelectric layer 80 to urge the piezoelectric layer 80 to apply pressure against the anode region 40. For example, the second voltage may be substantially the same as the first voltage.
In various implementations, at S830, as a result of receiving the second voltage, the piezoelectric layer 60 or 80 generates a mechanical force against the cathode structure 10 or the anode region 40. More specifically, when a current collector is between the piezoelectric layer and the electrode, the piezoelectric layer generates a force against the current collector at S830, and the current collector transmits that force to the cathode structure 10 or the anode region 40. As a result of the application of the mechanical force by the piezoelectric layer, the quality of the interface between various layers of the battery may be maintained or improved. For example, the quality of the interface between the cathode structure 10/anode region 40 and the current collector 20/50, the interface between the cathode structure 10/anode region 40 and the solid-state electrolyte, or even the interface between the solid-state electrolyte and the cathode structure 10/anode region 40 on the opposite side of the battery. For example, improving or maintain the interface between the layers of the battery includes improving or maintaining the surface of the contact area between those layers. Accordingly, if an electrode (i.e., cathode structure 10/anode region 40) undergoes material losses, then by being pressed against the solid-state electrolyte, the electrode can maintain an appropriate level of contact surface area at the interface with the solid-state electrolyte.
In various implementations, at S840, the method determines whether a voltage such as the first voltage discussed above is still detected at either the piezoelectric layer 60 or 80. If at S840, a voltage is detected at either of the piezoelectric layers 60 or 80, then the method continues to S820 to apply a second voltage, as discussed above. If at S840 a voltage is not detected at either of the piezoelectric layers 60 or 80, then the method goes to S850 and the second voltage is no longer applied to either of the piezoelectric layers 60 or 80.
In the following, further features, characteristics and advantages of the instant application will be described by means of items:
Item 1: A solid-state battery cell includes a cathode region, an anode region, a separator interconnecting the cathode region and the anode region, the separator including a solid-state electrolyte, a cathode current collector on a surface of the cathode region, an anode current collector on a surface of the anode region, a first piezoelectric layer on a surface of the cathode current collector opposite the cathode region, and a second piezoelectric layer on a surface of the anode current collector opposite the anode region.
Item 2: The solid-state battery cell of item 1, wherein at least one of the first piezoelectric layer and the second piezoelectric layer is powered by a voltage source separate from the solid-state battery cell.
Item 3: The solid-state battery cell of item 1 or 2, wherein at least one of the first piezoelectric material layer and the second piezoelectric material layer is powered by the solid-state battery cell.
Item 4: The solid-state battery cell of any of items 1-3, wherein the solid-state electrolyte includes a ceramic electrolyte.
Item 5: The solid-state battery cell of any of items 1-4, wherein at least one of the first piezoelectric material layer and the second piezoelectric material layer include a ceramic material. For example, the ceramic material is a 3D-printed ceramic material.
Item 6: A solid-state battery cell includes a cathode region, a first anode region, a second anode region on an opposite side of the cathode region from the first anode region, a first separator interconnecting the cathode region and the first anode region, the first separator including a first solid-state electrolyte, a second separator interconnecting the cathode region and the second anode region, the second separator including a second solid-state electrolyte, a first anode current collector on a surface of the first anode region, a second anode current collector on a surface of the second anode region, a first piezoelectric layer on a surface of the first anode current collector, and a second piezoelectric layer on a surface of the second anode current collector.
Item 7: The solid-state battery cell of item 6, wherein at least one of the first piezoelectric layer and the second piezoelectric layer is connected to a voltage source.
Item 8: The solid-state battery cell of item 6 or 7, wherein at least one of the first solid-state electrolyte and the second solid-state electrolyte includes a ceramic electrolyte.
Item 9: The solid-state battery cell of any of items 6-8, wherein at least one of the first anode region and the second anode region includes a lithium anode.
Item 10: A battery includes a plurality of solid-state cells arranged in a stack, the stack including a first cell at a first end thereof and a last cell at a second end thereof opposite the first end. Each of the plurality of cells includes a cathode region, an anode region, a separator interconnecting the cathode region and the anode region, the separator including a solid-state electrolyte, a cathode current collector on a surface of the cathode region of the first cell, and an anode current collector on a surface of the anode region of the last cell, a first piezoelectric layer on a surface of the cathode current collector, and a second piezoelectric layer on a surface of the anode current collector.
Item 11: The battery of item 10, wherein at least one of the first piezoelectric material layer and the second piezoelectric material layer is connected to a voltage source located inside the battery.
Item 12: The battery of item 10 or 11, wherein at least one of the first piezoelectric material layer and the second piezoelectric material layer is connected to one or more of the plurality of solid-state cells.
Item 13: The battery of any of items 10-12, wherein the battery is encased in a receptacle, and the voltage source is inside the receptacle.
Item 14: A battery includes a plurality of solid-state cells arranged in a stack, the stack including a first cell at a first end thereof and a last cell at a second end thereof opposite the first end. Each of the plurality of cells includes a cathode region, a first anode region, a second anode region on an opposite side of the cathode region from the first anode region, a first separator interconnecting the cathode region and the first anode region, the first separator including a first solid-state electrolyte, a second separator interconnecting the cathode region and the second anode region, the second separator including a second solid-state electrolyte, a first anode current collector on a surface of the first anode region of the first cell, a second current collector on a surface of the second anode region of the last cell, a first piezoelectric layer on a surface of the first anode current collector, and a second piezoelectric layer on a surface of the second anode current collector.
Item 15: A method of operating a solid-state battery cell includes detecting a first voltage at one of the first piezoelectric layer and the second piezoelectric layer, and when the first voltage is a non-zero voltage, applying a second voltage to the one of the first piezoelectric layer and the second piezoelectric layer.
Item 16: The method of item 15, wherein the at least one of the first piezoelectric material layer and the second piezoelectric material layer generate pressure against an adjacent layer due to the applied second voltage.
Item 17: The method of item 15 or 16, wherein the applied second voltage is equal to the detected first voltage.
Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.
It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.
The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it may be seen that various features are grouped together in various examples for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed example. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.
