U.S. patent application number 12/535632 was filed with the patent office on 2010-02-11 for electrochemical cell including functionally graded and architectured components and methods.
This patent application is currently assigned to Sakti3, Inc.. Invention is credited to Fabio Albano, Ann Marie Sastry, Chia-Wei Wang.
Application Number | 20100035152 12/535632 |
Document ID | / |
Family ID | 41653237 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100035152 |
Kind Code |
A1 |
Sastry; Ann Marie ; et
al. |
February 11, 2010 |
ELECTROCHEMICAL CELL INCLUDING FUNCTIONALLY GRADED AND
ARCHITECTURED COMPONENTS AND METHODS
Abstract
Electrochemical cells or batteries featuring functional
gradations, and having desirable, periodic configurations, and
methods for making the same. One or more methods, in alone or in
combination, are utilized to fabricate components of such
electrochemical cells or batteries, which are designed to achieve
certain thermal, mechanical, kinetic and spatial characteristics,
and their effects, singly and in all possible combinations, on
battery performance. The thermal characteristics relate to
temperature distribution during charge and discharge processes. The
kinetic characteristics relate to rate performance of the cells or
batteries such as the ionic diffusion process and electron
conduction. The mechanical characteristics relate to lifetime and
efficiency of the cells or batteries such as the strength and
moduli of the component materials. Finally, the spatial
characteristics relate to the energy and power densities, stress
and temperature mitigation mechanisms, and diffusion and conduction
enhancements. The electrochemical cells or batteries constructed
according to the methods presented in this invention are useful for
all applications that require high rate performance, high
energy/power density, good durability, high safety and long
lifetime.
Inventors: |
Sastry; Ann Marie; (Ann
Arbor, MI) ; Albano; Fabio; (Canton, MI) ;
Wang; Chia-Wei; (Ann Arbor, MI) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Sakti3, Inc.
Ann Arbor
MI
|
Family ID: |
41653237 |
Appl. No.: |
12/535632 |
Filed: |
August 4, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61086161 |
Aug 5, 2008 |
|
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Current U.S.
Class: |
429/218.1 ;
204/192.17; 264/400; 427/569; 427/575; 427/58; 427/8 |
Current CPC
Class: |
B29C 59/02 20130101;
H01M 2004/025 20130101; H01M 4/0404 20130101; H01M 10/0565
20130101; H01M 4/505 20130101; C23C 16/511 20130101; H01M 10/6554
20150401; C23C 4/134 20160101; H01M 4/382 20130101; H01M 4/0428
20130101; H01M 4/0471 20130101; H01M 4/131 20130101; C23C 14/042
20130101; C23C 14/08 20130101; C23C 14/22 20130101; H01M 4/13
20130101; H01M 4/0423 20130101; H01M 4/139 20130101; H01M 4/0426
20130101; B82Y 30/00 20130101; H01M 10/613 20150401; H01M 2004/021
20130101; Y02E 60/10 20130101; C23C 14/025 20130101; B29C 59/16
20130101; H01M 4/70 20130101; H01M 4/0407 20130101; H01M 4/0419
20130101; H01M 4/134 20130101; C23C 14/48 20130101; C23C 16/45525
20130101; C23C 16/44 20130101 |
Class at
Publication: |
429/218.1 ;
427/58; 204/192.17; 264/400; 427/569; 427/575; 427/8 |
International
Class: |
H01M 4/58 20100101
H01M004/58; B05D 5/12 20060101 B05D005/12; C23C 14/34 20060101
C23C014/34; B29C 35/08 20060101 B29C035/08; B05D 3/06 20060101
B05D003/06; C23C 16/52 20060101 C23C016/52 |
Claims
1. A micro-architectured electrochemical cell and/or battery device
comprising: an anode; a cathode arranged anti-symmetrically with
the anode; a predetermined distance between the cathode and the
anode; an electrical insulation provided to separate the anode from
the cathode, the electrical insulation being characterized by a
graded material property that changes within a portion of the
predetermined distance or one or more layers of insulating material
to separate the anode from the cathode; a nanocomposite anode
material characterizing the anode, the nanocomposite anode material
having one or more first intensive characteristics that is a
function of one or more second extensive characteristics; a
nanocomposite cathode material characterizing the cathode, the
nanocomposite cathode material having one or more first intensive
characteristics that is a function of one or more second extensive
characteristics; an electrolyte material provided between the anode
and the cathode; a cathode current collector in communication with
the cathode; and an anode current collector in communication with
the anode.
2. The device of claim 1 further comprising a substrate to support
the current collector if depositing current collector material
mechanical properties are not suitable for further deposition.
3. An electrochemical cell comprising: an anode member having one
or more first spatial features and formed substantially from a
first nanocomposite material, the first nanocomposite material
having an average feature size ranging from about 50 .ANG. to about
500 nanometers, the first nanocomposite material having a first
resistivity value of greater than 8 microohms centimeters; a
cathode member having one or more second spatial features, the
cathode member being operably coupled the anode member and formed
substantially from a second nanocomposite material, the second
nanocomposite material having an average feature size ranging from
about 50 .ANG. to about 500 nanometers, the second nanocomposite
having a second resistivity value of greater than 14.3 ohms
centimeters; a predetermined gap between the anode and the cathode,
the predetermined gap being greater than 500 nanometers; an
electrolyte provided between the anode and the cathode; a separator
provided between the anode and the cathode; a first current
collector coupled to the anode via at least a first contact; and a
second current collector coupled to the cathode via at least a
second contact.
4. The electrochemical cell of claim 3 further comprising an
aggregate resistance, the aggregate resistance being derived from a
sum of resistance values from one or more leads, the first contact,
the second contact, the first resistance value, the second
resistance value, and one or more resistance values between one or
more different elements of the electrochemical cell.
5. The electrochemical cell of claim 3 wherein the first
nanocomposite material is substantially free from a localized
charge of 1 eV and greater.
6. The electrochemical cell of claim 3 wherein the second
nanocomposite material is substantially free from a localized
charge of 1 eV and greater.
7. The electrochemical cell of claim 3 wherein the first
nanocomposite material is selected from at least a transition
metal, oxide of a metal, Groups IA, IVA, VIA, and IIB.
8. The electrochemical cell of claim 3 wherein the second
nanocomposite material is selected from at least a transition
metal, oxide of a metal, Groups IA, VIII, IVA, VIA, IB, IVB and
VIIB.
9. The electrochemical cell of claim 3 wherein the electrolyte is
selected from a liquid, solid, or gel.
10. The electrochemical cell of claim 3 wherein the electrolyte is
selected from a ceramic, a semiconductor, a polymeric material, or
any material in an aqueous solution.
11. The electrochemical cell of claim 3 wherein the electrolyte is
either homogeneous or inhomogeneous.
12. The electrochemical cell of claim 3 wherein the electrolyte is
a nanocomposite, microcomposite, or other heterogeneous
structure.
13. The electrochemical cell of claim 3 wherein the electrolyte
comprises one or more first intensive characteristics referenced
against one or more second extensive characteristics.
14. The electrochemical cell of claim 3 wherein the anode member
and/or cathode member comprises a dopant to maintain surfaces of
either or both the anode member and/or the cathode member
substantially free from dendrites.
15. The electrochemical cell of claim 14 wherein the dopant is
selected from any one or more combinations of Groups IA through
VIIA, and Groups IIB-VIIB, and Group VIII, inclusive and in any
permutation.
16. The electrochemical cell of claim 14 wherein the dopant is
provide in a homogeneous configuration or graded configuration.
17. A method for fabricating an electrode for an electrochemical
cell, the method comprising: providing a substrate member having a
predetermined spatial pattern; depositing a thickness of material
using one or more species overlying the predetermined spatial
pattern in a conformal manner, the thickness of material being
characterized as a nanocomposite structure having an average
feature size of about 500 nanometers and less; adjusting one or
more parameters related to the deposition during a time period
associated with the deposition of the thickness of material from a
first spatial region of the thickness of material to a second
spatial region of the thickness of material; and outputting an
electrode element having a graded feature of one or more
characteristics from the first spatial region to the second spatial
region.
18. The method of claim 17 wherein the electrodes are formed using
at least one technique from the group of evaporation, physical
vapor deposition (PVD), chemical vapor deposition, low pressure
chemical vapor deposition (LPCVD), atomic layer deposition (ALD),
direct laser writing (DLW), sputtering, radio frequency magnetron
sputtering, microwave plasma enhanced chemical vapor deposition
(MPECVD), pulsed laser deposition (PLD), nanoimprint, ion
implantation, laser ablation, spray deposition, spray pyrolysis,
spray coating or plasma spraying.
19. The method of claim 17 further comprises adding a non liquid
electrolyte for an electrochemical cell using the electrode
element, the non-liquid electrolyte being made using a process
selected from physical vapor deposition, laser deposition,
centrifuge, spinning, microwave, thermal gradient, sintering, spray
deposition, and chemical vapor deposition.
20. The method of claim 19 wherein an anode element, the
electrolyte, and a cathode member are deposited sequentially or in
reverse order.
21. The method of claim 17 wherein the one or more characteristics
is selected from an intensive property including mass density,
energy density, power density, composition, concentration,
thermal/electronic/ionic conductivities, thermal/ionic
diffusivities, maximum strain, ultimate strength, moduli,
ductility, and plasticity.
22. The method of claim 17 wherein the electrode element is
characterized by an optimized morphology created for neutralizing
internal stresses, stopping crack growth, maximizing material
strength, and stabilizing active material structure in anode,
electrolyte, cathode and current collectors.
23. The method of claim 17 further comprising a refresh process to
reintroduce the graded feature of one or more characteristics from
the first spatial region to the second spatial region if the graded
feature is diminished from the first spatial region to the second
spatial region.
24. The method of claim 17 wherein the predetermined spatial
pattern is an electrode design, the electrode design being provided
by a mathematical process.
25. The method of claim 24 wherein the mathematical process uses a
minimization or maximization of an intensive characteristic from
within an allowed set of material characteristics.
26. The method of claim 25 wherein the mathematical process is
selected from at least a surrogate-base analysis, genetic
algorithm, adaptive topology optimization, design of experiments,
ANOVA/MANOVA, basin based analysis, solid isotropic microstructure
with intermediate mass penalization (SIMP), power penalized
stiffness model, topology optimization of continuum structure,
normal boundary intersection (NBI) optimization method,
multivariable optimization method, or multidisciplinary design
optimization.
27. The method of claim 17 wherein the depositing and adjusting is
provided in a deposition chamber.
28. The method of claim 27 wherein the deposition chamber is
provided to output a complete battery.
29. A method for fabricating an electrochemical cell, the method
comprising: providing a substrate member having a predetermined
spatial pattern; depositing a first thickness of material using one
or more species overlying the predetermined spatial pattern in a
conformal manner, the first thickness of material being
characterized as a nanocomposite structure having an average
feature size of about 500 nanometers and less; adjusting one or
more parameters related to the deposition during a time period
associated with the deposition of the first thickness of material
from a first spatial region of the first thickness of material to a
second spatial region of the first thickness of material to form a
first electrode element having a graded feature of one or more
characteristics from the first spatial region to the second spatial
region; forming an electrolyte overlying the first electrode
element; and forming a second electrode element overlying the
electrolyte.
30. The method of claim 29 wherein the first electrode element, the
second electrode element, and the electrolyte are provided within
one or more deposition chambers.
31. The method of claim 29 wherein the first electrode element is a
cathode and the second electrode element is an anode.
32. The method of claim 29 wherein the first electrode element is
an anode and the second electrode element is a cathode.
33. The method of claim 29 further comprising depositing an anode
current collector and a cathode current collector.
34. The method of claim 29 wherein the first electrode element, the
electrolyte, and the second electrode element are deposited
sequentially.
35. The method of claim 29 wherein the first electrode element, the
electrolyte, and the second electrode element are deposited
sequentially and continuously without breaking vacuum.
36. The method of claim 29 further comprising providing a separator
between the first electrode element and the second electrode
element.
37. The method of claim 36 wherein the separator is provided within
the electrolyte.
38. A method for fabricating an electrode for an electrochemical
cell, the method comprising: providing a substrate member
comprising a current collector; depositing a thickness of material
using one or more species overlying a surface region of the
substrate member, the thickness of material being characterized as
a nanocomposite material; adjusting one or more parameters during a
time period associated with the depositing of the thickness of
material from a first spatial region of the thickness of material
to a second spatial region of the thickness of material; and
causing formation of an electrode element having a graded feature
of one or more characteristics from the first spatial region to the
second spatial region.
39. A method for fabricating a periodic geometric feature for an
electrochemical cell, the method comprising: masking and exposing a
region of substrate for an electrode member or current collector,
or exposing the electrode member itself, by periodically varying
one or more parameters selected from at least a magnetic field, an
electric field, a temperature gradient, and an optical beam
intensity to seed the exposed region of the substrate with one or
more precursors.
40. The method of claim 39 further comprising periodically
modifying one or more spatial regions of the exposed region of the
substrate for the electrode member or the electrode member itself,
using at least one or more processes selected from drilling,
masking, molding, indentation, nanoimprint, abrasive, laser
ablation, radiation and neutron scattering.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/086,161, filed Aug. 5, 2008, the disclosure of
which is hereby incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to electrochemical
cells. More particularly, the present invention provides methods
and devices having a functionally graded and an architectured
component for electrode(s). Merely by way of example, the invention
can be applied to a variety of applications including automotive,
telecommunication, general energy storage, portable electronics,
power tools, power supplies, among others.
[0003] As noted, electrochemical cells are used to store energy for
a variety of applications. These applications include portable
electronics such as cell phones, personal digital assistants, music
players, video cameras, and the like. Applications also include
power tools, power supplies for military use (e.g., communications,
lighting, imaging and the like), power supplies for aerospace
applications (e.g., power for satellites), and power supplies for
vehicle applications (e.g., hybrid electric vehicles, plug-in
hybrid electric vehicles, and fully electric vehicles), and
others.
[0004] Conventional electrochemical cells are manufactured using
paper-making techniques. The conventional electrochemical cells
have been fabricated without accounting for internal mechanical
stresses, intercalation and thermal induced stresses. Thus,
drawbacks exist with these conventional cells. The drawbacks
include limited lifetime, premature failure, limited storage
capability, and other imperfections. To increase the
electrochemical cell energy and power density, without compromising
lifetime, other manufacturing approaches have been proposed.
Concurrently, electrode architectures have been developed that use
thin-film, microarchitectured, functionally graded materials such
as Li.sub.2MnO.sub.3-stabilized LiMO.sub.2 (M.dbd.Mn, Ni, Co)
described in "M. M. Thackeray, S.-H. Kang, C. S. Johnson,
Li.sub.2MnO.sub.3-stabilized LiMO.sub.2 (M.dbd.Mn, Ni, Co)
Electrodes for Lithium-Ion Batteries, Journal of Material Chemistry
17, 3112-3125, 2007". This type of cells typically has non-aqueous
electrolyte sandwiched between a cathode layer and an anode layer
of similar geometry. For example, in a typical thin-film lithium
ion cell, the cathode is often, LiCoO.sub.2, LiMn.sub.2O.sub.4,
while the electrolyte is often lithium-phosphorous-oxynitride
(LIPON) and anode is lithium foil. Thin-film Li-ion cells have been
demonstrated to have energy densities of 1,000 Wh/Kg and power
densities of 10,000 W/Kg with potentially unlimited number of
discharge-charge cycles.
[0005] A central challenge to create cost-effectively
microarchitectured and functionally graded electrodes, cells or
batteries is precisely tuning material properties for the specific
role of that material needed. In order to achieve precise material
properties spanning through an electrochemical cell manufacturing
has to be inside a controlled environment. Traditional thin-film
electrochemical cells have been manufactured inside the clean room
for aerospace and implantable batteries. However, such a process is
too costly and can not be used for mass production of high-tech
electrochemical cells.
[0006] As a consequence, cost-effective high throughput
manufacturing techniques and microarchitectured and functionally
graded electrodes are desirable.
SUMMARY OF THE INVENTION
[0007] According to the present invention, techniques for
electrochemical cells are provided. More particularly, the present
invention provides methods and devices having a functionally graded
and an architectured component for electrode(s). Merely by way of
example, the invention can be applied to a variety of applications
including automotive, telecommunication, general energy storage,
portable electronics, power tools, power supplies, among
others.
[0008] Embodiments of the present invention comprise a
microarchitectured thin-film electrochemical cell with continuously
deposited layers that have varying at least one of (or more)
intensive properties as a function of at least one of (or more) the
extensive properties, and related methods to manufactured such type
of electrochemical cell. The intensive properties are, but are not
limited to, density, composition, concentration,
thermal/electronic/ionic conductivities, thermal/ionic
diffusivities, maximum strain, ultimate strength, moduli,
ductility, and plasticity, combinations, and the like. Also, the
extensive properties are, but are not limited to, volume, area, and
thickness, combinations, and the like.
[0009] Merely by way of example, the invention has been provided
with use of lithium based cells, but it would be recognized that
other materials such as zinc, silver, copper and nickel could be
designed in the same or similar fashion. Deposition of layers and
formation of microarchitecture of layers are accomplished by one of
several processes, used separately or in conjunction with one
another. Continuous manufacturing of electrodes and batteries is
accomplished via a variety of techniques. The manufacturing
processes of the present invention is finished inside the
deposition chamber, which is equipped with sufficient materials to
create complete batteries, via deposition of anode, cathode,
electrolyte, separator and current collector layers. As used
herein, the term "continuous process" shall mean a substantially
free from any breaks or each of the processes is within a
predetermined environment, e.g., vacuum. Batteries constructed
using this approach have at least one anode, one cathode, an
electrolyte, and may have a separator, depending upon the
electrochemistry used. Of course, there can be other variations,
modifications, and alternatives.
[0010] An embodiment of the present invention, one or more material
is provided that comprises a microarchitectured morphology having
at least one mechanism to mitigate intercalation and thermal
expansion stresses, strengthen the electrode material.
[0011] In another embodiment of the present invention, one or more
material is provided that comprises a functionally graded structure
having one or more intensive properties varying as function of one
or more extensive properties of the material. Intensive
characteristics include but are not limited to density,
composition, concentration, thermal/electronic/ionic
conductivities, thermal/ionic diffusivities, maximum strain,
ultimate strength, moduli, ductility, and plasticity. Extensive
characteristics include but are not limited to volume, area, and
thickness.
[0012] In yet another embodiment of the present invention, an anode
material is provided that having a composition containing at least
one element from Groups IA, IVA, VIA, and IIB; a cathode material
is provided that having a composition containing at least one
element from Groups IA, VIII, IVA, VIA, IB, IVB and VIIB;
[0013] In a still another embodiment of the present invention,
microarchitecture is created using one or more of the following
techniques. The anode current collector material is formed on a
microarchitectured substrate by using physical vapor deposition
techniques, or is a stand-alone microarchitectured film without
needing a substrate. The cathode current collector material is
formed on a microarchitectured substrate by using physical vapor
deposition techniques, or it is a stand-alone microarchitectured
film without requiring a substrate. The microarchitectured
electrochemical cell comprises anode, electrolyte and cathode
deposited sequentially or in reverse order by physical vapor
deposition techniques. As used herein, the term
"microarchitectured" shall be interpreted by ordinary meaning and
the description herein should not be limiting. As an example, the
term microarchitectured shall include feature sizes ranging from
about 100 nanometers to about 100 micrometers and less than 500
micrometers, but can be others.
[0014] In another embodiment of the present invention, a method is
provided that comprises of manipulating the configuration of the
electrode to create breadloafing. The anode connected with the
anode current collector and a second side is interlocked with the
electrolyte. The electrolyte of present invention, wherein a first
side is interlocked with the anode layer and a second side is
interlocked with the cathode layer. The cathode of claim 1, wherein
a first side is interlocked with the electrolyte and a second side
is connected with the cathode current collector.
[0015] In another embodiment of the present invention, methods are
provided that comprise of manipulating the materials to form
nanocomposite electrode. A nanocomposite architecture of the
cathode material to neutralize internal stresses, stop crack
growth, maximize material strength, and stabilize active material
structure. A nanocomposite material is formed by depositing two or
more layers of same material with different crystal structures. In
one embodiment, a nanocomposite material is formed by depositing
two or more layers of the same material with different crystal
structures, and using masks on alternate layers to create patterns.
In another embodiment, a nanocomposite material is formed by
depositing two or more layers of different materials. In yet
another embodiment, a nanocomposite material is formed by
depositing two or more layers of different materials, and using
masks on alternate layers to create patterns. In yet another
embodiment, a nanocomposite material is formed by depositing two or
more materials at the same time to create one or more nanodisperse
phases within the main matrix grains of active material. In another
embodiment, a nanocomposite material is formed by depositing two or
more materials at the same time to create dispersion of secondary
phases around the grain boundaries of the matrix of active
material. In yet another embodiment, a nanocomposite material is
formed by depositing two or more materials at the same time to
create a dispersion of secondary phases both inside and around the
grains of the matrix of active material. In another embodiment, a
nanocomposite material is formed by depositing two or more
materials at the same time to induce phase separation. As used
herein, the term nanocomposite shall include feature sizes ranging
from about 50 .ANG. about 500 nanometers and less, but can be other
sizes according to ordinary meaning.
[0016] In another embodiment of the present invention, methods are
provided that comprise of fabricating the functionally graded,
microarchitectured solid electrodes using a plurality of techniques
containing at least one from the group of evaporation, physical
vapor deposition (PVD), chemical vapor deposition, sputtering,
radio frequency magnetron sputtering, microwave plasma enhanced
chemical vapor deposition (MPECVD), pulsed laser deposition (PLD),
laser ablation, spray deposition, spray pyrolysis, spray coating or
plasma spraying, and fabricating functionally graded,
microarchitectured nonaqueous electrolyte using a plurality of
techniques containing at least one from the group of physical vapor
deposition, laser deposition, centrifuge, spinning, microwave,
thermal control, spray, and chemical vapor deposition.
[0017] In another embodiment of the present invention, methods are
provided that comprise of masking, and deposition to define a
precise morphology of active region for neutralizing internal
stresses, stopping crack growth, maximizing material strength, and
stabilizing active material structure in anode, electrolyte,
cathode and current collectors.
[0018] In another embodiment of the present invention, methods are
provided that morphology of periodic, irregular but not arbitrary
electrode is identified by using one of the optimization
techniques, but not limited to, surrogate-base analysis, genetic
algorithm, adaptive topology optimization, design of experiments,
ANOVA/MANOVA, basin based analysis, solid isotropic microstructure
with intermediate mass penalization (SIMP), power penalized
stiffness model, topology optimization of continuum structure,
normal boundary intersection (NBI) optimization method,
multivariable optimization method, or multidisciplinary design
optimization.
[0019] In another embodiment of the present invention, methods are
provided that comprise of preparing microarchitectured electrodes.
The microarchitectured electrode is characterized by periodic
pattern by using a patterning technique selected from a group
including but not limited to: periodically varying magnetic field,
electric field, temperature gradient, and optical beam intensity,
periodically seeding the current collector or substrate with
precursor, periodically modifying the current collector or
substrate using drilling, masking, molding, indentation,
nanoimprint, abrasive, laser ablation, radiation and neutron
scattering.
[0020] In a specific embodiment, the various cell elements can be
formed using one or more techniques. These techniques include
evaporation, physical vapor deposition (PVD), chemical vapor
deposition, low pressure chemical vapor deposition (LPCVD), atomic
layer deposition (ALD), direct laser writing (DLW), sputtering,
radio frequency magnetron sputtering, microwave plasma enhanced
chemical vapor deposition (MPECVD), pulsed laser deposition (PLD),
nanoimprint, ion implantation, laser ablation, spray deposition,
spray pyrolysis, spray coating or plasma spraying. Of course, there
can be other variations, modifications, and alternatives.
[0021] Moreover, the present invention provides a
micro-architectured electrochemical cell and/or battery device. The
cell and/or battery device includes an anode and a cathode arranged
anti-symmetrically with the anode. In a specific embodiment, the
device has a predetermined distance between the cathode and the
anode. An electrical insulation is provided to separate the anode
from the cathode. In a specific embodiment, the electrical
insulation is characterized by a graded material property that
changes within a portion of the predetermined distance or one or
more layers of insulating material to separate the anode from the
cathode. In a specific embodiment, the device has a nanocomposite
anode material characterizing the anode. In a preferred embodiment,
the nanocomposite anode material has one or more first intensive
characteristics that is a function of one or more second extensive
characteristics. A nanocomposite cathode material characterizes the
cathode. In a specific embodiment, the nanocomposite cathode
material has one or more first intensive characteristics that is a
function of one or more second extensive characteristics. In a
specific embodiment, an electrolyte material is provided between
the anode and the cathode. In a specific embodiment, the device has
a cathode current collector in communication with the cathode and
an anode current collector in communication with the anode.
[0022] Still further, the present invention provides an
electrochemical cell. The cell has an anode member having one or
more first spatial features and formed substantially from a first
nanocomposite material, which has an average feature size ranging
from about 50 .ANG. to about 500 nanometers. In a specific
embodiment, the first nanocomposite material has a first
resistivity value of greater than 8 micro-ohms centimeters, but can
be others. In a specific embodiment, the cell has a cathode member
having one or more second spatial features. The cathode member is
operably coupled the anode member and is formed substantially from
a second nanocomposite material, which has an average feature size
ranging from about 50 .ANG. to about 500 nanometers. In a specific
embodiment, the second nanocomposite has a second resistivity value
of greater than 14.3 ohms centimeters, but can be others. In a
specific embodiment, the device has a predetermined gap between the
anode and the cathode. In a specific embodiment, the predetermined
gap is greater than 500 nanometers. The device also has an
electrolyte provided between the anode and the cathode and a
separator provided between the anode and the cathode. The device
has a first current collector coupled to the anode via at least a
first contact and a second current collector coupled to the cathode
via at least a second contact.
[0023] Still further, the present invention provides a method for
fabricating an electrochemical cell. The method includes providing
a substrate member having a predetermined spatial pattern, e.g.,
patterned, periodic. The method includes depositing a first
thickness of material using one or more species overlying the
predetermined spatial pattern in a conformal manner. In a specific
embodiment, the first thickness of material is characterized as a
nanocomposite structure having an average feature size of about 500
nanometers and less. The method includes adjusting one or more
parameters related to the deposition during a time period
associated with the deposition of the first thickness of material
from a first spatial region of the first thickness of material to a
second spatial region of the first thickness of material to form a
first electrode element having a graded feature of one or more
characteristics from the first spatial region to the second spatial
region. The method forms an electrolyte overlying the first
electrode element and forms a second electrode element overlying
the electrolyte.
[0024] In an alternative specific embodiment, the present invention
provides a method for fabricating an electrode for an
electrochemical cell. The method includes providing a substrate
member comprising a current collector. The method includes
depositing a thickness of material using one or more species
overlying a surface region of the substrate member. In a specific
embodiment, the thickness of material is characterized as a
nanocomposite material. The method includes adjusting one or more
parameters during a time period associated with the depositing of
the thickness of material from a first spatial region of the
thickness of material to a second spatial region of the thickness
of material. The method also includes causing formation of an
electrode element having a graded feature of one or more
characteristics from the first spatial region to the second spatial
region.
[0025] Moreover, the present invention provides a method for
fabricating a periodic geometric feature for an electrochemical
cell. The method includes masking and exposing a region of
substrate for an electrode member or current collector by
periodically varying one or more parameters selected from at least
a magnetic field, an electric field, a temperature gradient, and an
optical beam intensity to seed the exposed region of the substrate
with one or more precursors. In other embodiments, the method also
includes periodically modifying one or more spatial regions of the
exposed region of the substrate using at least one or more
processes selected from drilling, masking, molding, indentation,
nanoimprint, abrasive, laser ablation, radiation and neutron
scattering. Of course, there can be other variations,
modifications, and alternatives.
[0026] The benefits of the invention include the ability it confers
in rational design and combination of multiple materials to produce
electrochemical cells, in novel arrangements. These in, turn,
confer superior properties to designed cells, and elimination of
costly-trial and error in construction of prototype cells.
Depending upon the embodiment, one or more of these benefits can be
achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 Periodic, irregular but not arbitrary electrode
according to an embodiment of the present invention.
[0028] FIGS. 2 (A)-(B) are simplified cross-sectional views showing
fabrication of a functionally graded electrode according to an
embodiment of the present invention.
[0029] FIGS. 3(A)-(C) are simplified cross-sectional views showing
fabrication of an electrode exhibiting a sinusoidal
microarchitecture according to an embodiment of the present
invention.
[0030] FIGS. 4(A)-(D) are simplified cross-sectional views showing
fabrication of an electrode exhibiting a nanocomposite material for
electrode according to an alternative embodiment of the present
invention.
[0031] FIG. 5(A) illustrates a cathode with thin-film design
according to an alternative embodiment of the present
invention;
[0032] FIG. 5(B) illustrates a cathode with column design according
to an alternative embodiment of the present invention;
[0033] FIG. 5(C) illustrates a cathode with sinusoidal design
according to an alternative embodiment of the present
invention;
[0034] FIG. 5(D) illustrates contours of von-Mises stress on column
design electrode.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0035] According to the present invention, techniques relate to
manufacture of three-dimensional interdigitated electrochemical
cells. More particularly, the present invention provides a method
and system for manufacture of three-dimensional elements for
three-dimensional interdigitated electrochemical cells. Merely by
way of example, the invention has been provided with use of lithium
based cells, but it would be recognized that other materials such
as zinc, silver, copper and nickel could be designed in the same
fashion. Additionally, such batteries can be used for a variety of
applications such as portable electronics (cell phones, personal
digital assistants, music players, video cameras, and the like),
power tools, power supplies for military use (communications,
lighting, imaging and the like), power supplies for aerospace
applications (power for satellites), and power supplies for vehicle
applications (hybrid electric vehicles, plug-in hybrid electric
vehicles, and fully electric vehicles). The design of such
batteries is also applicable to cases in which the battery is not
the only power supply in the system, and additional power is
provided by a fuel cell, other battery, IC engine or other
combustion device, capacitor, solar cell, etc. Of course, there can
be other variations, modifications, and alternatives.
[0036] It is to be understood that both the forgoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed. It may be noted that, as used in the specification and the
appended claims, the singular forms "a", "an", and "the" include
plural referents unless the context clearly dictates otherwise.
Thus, for example, reference to "a material" may include mixture of
materials; reference to "a compound" may include multiple
compounds.
[0037] In a specific embodiment, the present invention provides a
structure that is irregular in shape, but has a periodic spatial
feature. In a preferred embodiment, the irregularity is not
arbitrary in shape or size. The irregularity has a predetermined
spatial feature. As shown in FIG. 1, the structure has a first
periodic spatial feature domain and a second periodic spatial
feature domain. In a specific embodiment, each of the domains
include common features, which may include a pyramidal shape,
trapezoidal shape, dome shape, or any other shapes, including
combinations, and the like. Of course, there can be other
variations, modifications, and alternatives.
[0038] In a specific embodiment of the present invention, a device
of electrochemical cells comprises of functionally graded and
periodically spatial feature electrodes that would benefit its
usage to extend lifetime and efficiency by mitigating the stress
due to the ionic intercalation, alleviating thermal stress due to
the electrochemical reaction, stabilizing the host material lattice
structure during the charge-discharge process, and increasing the
kinetic properties of the host material. The electrode described
herein is referring to anode and cathode of a single
electrochemical cell. The anode and cathode referring herein are
based on the electric current direction and the mode. Therefore,
the anode is the negative terminal in a discharge electrochemical
cell (or also known as galvanic cell), but it would the positive
terminal in a recharging electrochemical cell (or also known as
electrolytic cell). The cathode is vice versa. The functionally
graded electrodes described herein are characterized by the
variation in composition and structure gradually over spatially
volume of single electrode or whole electrochemical cells. The
periodically spatial feature of electrodes or electrochemical cells
of the device described herein is employed to strengthen material
performance locally to facilitate the ionic diffusion, electronic
conduction, and mitigating stress inside the electrodes.
[0039] One advantage of using functionally graded electrode is that
a specific function of a material is integrated with the host
active material so that the benefit of that specific function would
be added to improve overall electrode performance. The host active
material referring herein is the material within an electrode
responsible for the electronic energy exchange with counter
electrode during the electrochemical reaction. The function
described herein includes, but not limited to, mitigating
intercalation stress due to the host material lattice increment,
alleviating thermal stress due to the energy exchange within the
whole device, and increasing the kinetic properties of the
electrode in specific region, etc. For example, utilizing
Li.sub.2MnO.sub.3 will stabilize LiMO.sub.2 lattice structure,
where M include Mn, Ni and Co, during the charge-discharge process
in a Li ion battery as described in U.S. Pat. No. 6,680,143 B2. But
in this patent, the function of stabilizing lattice structure of
the host active material is the only one.
[0040] In another embodiment of the present invention, a method is
provided that periodically spatial feature of the electrode is
identified as shown in FIG. 1. As shown, the diagram includes a
first period and a second period according to a specific
embodiment. In a specific embodiment, each of the periods includes
various shapes, e.g., pyramid, trapezoid, dome. The spatial feature
of the electrode has impacts on the cell performance, such as
mitigating stresses due to Li+ intercalation and temperature
increment, etc. The preferred spatial feature will be identified by
utilizing any optimization techniques. The optimization method
comprises one technique from, but not limited to, the group of
surrogate-base analysis, genetic algorithm, adaptive topology
optimization, design of experiments, ANOVA/MANOVA, basin based
analysis, solid isotropic microstructure with intermediate mass
penalization (SIMP), power penalized stiffness model, topology
optimization of continuum structure, normal boundary intersection
(NBI) optimization method, multivariable optimization method, or
multidisciplinary design optimization. A preferred embodiment of
the present invention would be having a sinusoidal electrode
profile, wherein the amplitude and frequency of the sinusoid will
be determined by the optimization techniques listed above to have
robust performance, long lifetime, and high safety. Of course,
there can be other variations, modifications, and alternatives.
[0041] In certain embodiments of the present invention the
atmosphere associated with the electrode material deposition may be
changed. In one embodiment, the suitable atmosphere comprises a
oxygen atmosphere to create metal oxide materials. In other
embodiments the atmosphere may be a nitrogen atmosphere to create
electrolyte layers or nitride materials.
[0042] In some embodiments of the present invention the temperature
associated to the electrode materials formation may be varied,
continuously or step-wise to achieve particular materials
microstructures. In one embodiment an annealing step up to
800.degree. C. may be introduced to induce re-crystallization of
amorphous metal oxides material layers.
[0043] In other embodiments ambient temperature may be maintained
constant by cooling the substrate and removing heat at a constant
rate.
[0044] In some embodiments of the present invention, architectured
components of the battery, having geometric features ranging from
100 nanometers to 100 micrometers or below 500 micrometers, may be
fabricated using any suitable technique from the following list,
individually or in combination with each other: evaporation,
physical vapor deposition (PVD), chemical vapor deposition, low
pressure chemical vapor deposition (LPCVD), atomic layer deposition
(ALD), direct laser writing (DLW), sputtering, radio frequency
magnetron sputtering, microwave plasma enhanced chemical vapor
deposition (MPECVD), pulsed laser deposition (PLD), nanoimprint,
ion implantation, laser ablation, spray deposition, spray
pyrolysis, spray coating or plasma spraying. Of course, there can
be other variations, modifications, and alternatives.
[0045] In another embodiment of the present invention, preferred
materials for each member include, but not limited to, a substrate
material comprising of copper (Cu), aluminum (Al), stainless steel,
or other suitable conductive alloy in the form of a thin foil and
bearing, an anode material comprising lithium metal (Li), lithium
titanium oxide (Li.sub.4Ti.sub.5O.sub.12), graphite (C), or
meso-carbon structures such as microbeads or other microstructures;
an electrolyte material overlying the first electrode material and
comprising lithium phosphorus oxynitride (LIPON), lithium salts
such as LiClO.sub.4/LiPF.sub.6 mixed with poly-ethylene oxide
(PEO), poly-vinylidene fluoride (PVDF), or combination of PEO and
PVDF; and a cathode material overlying the electrolyte material and
comprising layered metal oxide materials such as LiCoO.sub.2,
spinel materials such as LiMn.sub.2O.sub.4, olivine materials such
as LiFePO.sub.4, Li(Ni.sub.1/3Mn.sub.1/3Co.sub.1/3)O.sub.2,
LiNixCoyAl.sub.(1-x-y)O.sub.2 (NCA),
LiNi.sub.xMnyCo.sub.(l-x-y)O.sub.2 (NCM). Further details of the
methods and devices can be found throughout the present
specification and more particularly below. The following
descriptions are merely examples, which should not unduly limit the
scope of the claims herein. One of ordinary skill in the art would
recognize other variations, modifications, and alternatives.
Example 1A functionally graded electrode and its manufacturing
technique
[0046] In FIGS. 2A and 2B, a functionally graded graphite anode is
created by focusing a laser beam through polymer electrolyte layer
by layer gradually from current collector to some desired distance
toward the surface of the polymer electrolyte with decreasing the
frequency of turning on-and-off the laser beam as the focus point
of the laser beam is gradually moved away from the current
collector. The electrode 1 comprises of polymer electrolyte
(LiPF.sub.6 plus polyethyleneoxide, PEO) 2 coated on top of copper
current collector 3 as detailed described in FIG. 2A. Because of
the high-energy of the Nd:YAG laser beam 4, the polymer in polymer
electrolyte, where the laser beam is aimed, will be graphitized as
9 in FIG. 2B. Also, because of decreasing the frequency of turning
on-and-off the laser beam (as shown in 6 to 8 in FIG. 2B), the area
of graphitized polymer in one layer will be decreased. Hence,
concentration of the graphite-like electrode will be gradually
decreased moving away from the current collector as 9 illustrated
FIG. 2B. The strength of color black 9 indicates the concentration
of graphite. Of course, there can be other variations,
modifications, and alternatives.
Example 2 Manufacturing of a Microarchitectured Electrode
[0047] In FIGS. 3A, B, and C, a microarchitectured
LiMn.sub.2O.sub.4 cathode having a periodic but non-arbitrary
geometry is made using a silicon (Si) substrate 11 as a template. A
Nd:YAG laser 13 is used to machine the substrate and remove
material 14, creating a set of channels and ridges that follows a
predetermined geometry obtained using a Computer Aided Design (CAD)
software as 12. The design is reflecting minimization of
intercalation stresses in the LiMn.sub.2O.sub.4 material according
to computer simulations. Once the substrate machining is completed
conformal material layers are deposited using physical vapor
deposition (PVD) onto the substrate. Respectively, a first titanium
(Ti) 18 attachment layer, having a thickness of 50 .ANG. or less,
followed by a second aluminum (Al) layer 19, having a thickness of
500 nanometers or higher, to serve as cathode current collector.
After deposition of the current collector, the active material
(LiMn.sub.2O.sub.4) 20 is formed following the same geometry
imprinted by the substrate. The thickness of the active material is
1-10 .mu.m. Of course, there can be other variations,
modifications, and alternatives.
Example 3 Manufacturing of a Nanocomposite Material for
Electrode
[0048] In FIGS. 4A, B, C, and D, a LiMn.sub.2O.sub.4 partially
stabilized cathode is fabricated by depositing conformal material
layers using physical vapor deposition (PVD). The same procedure
illustrated here can be used with or without the pre-existence of a
substrate 22. In this latter case, the current collector is also
serving as substrate material 22. A first layer of
LiMn.sub.2O.sub.4, 23, is deposited having a thickness of 100-500
nanometers. After the first layer is completed a mask, 26, having
geometric features of 100 nanometers or higher, is applied onto it
and a layer of Li.sub.2MnO.sub.3, 29, is deposited. Finally the
mask is removed and another layer of LiMn.sub.2O.sub.4, 34, having
a thickness of 100-500 nanometers, is deposited to embed the
Li.sub.2MnO.sub.3 features previously created.
[0049] Alternatively to using a mask, sputtering of
Li.sub.2MnO.sub.3 can be employed to create irregular second phase
regions on the first layer followed by a layer of
LiMn.sub.2O.sub.4, having a thickness of 100-500 nanometers
deposited to embed the second phases. As a third option is to
create a uniform layer of Li.sub.2MnO.sub.3 onto the first layer of
LiMn.sub.2O.sub.4 having a thickness of 50-100 nanometers and then
a new layer of LiMn.sub.2O.sub.4, having a thickness of 100-500
nanometers to sandwich the Li.sub.2MnO.sub.3 layer. The function of
the Li.sub.2MnO.sub.3 regions is to stabilize the spinel crystal
structure of LiMn.sub.2O.sub.4 when, during discharge the number of
Li+ ions is depleted and the structure becomes metastable. Normally
the cathode material would transform to a more stable spinel-type
configuration degrading the high potential and limiting capacity
and rechargeability of the electrode, however the second phase
prevents this from happening. Of course, there can be other
variations, modifications, and alternatives.
Example 4 Breadloafing
Sinusoidal Form of Electrodes Interdigitated with Electrolyte, and
Comb-Like Electrodes Interdigitated with Electrolyte
[0050] This example demonstrates the process of identifying a new
electrochemical cell with the optimal morphological shape of the
electrode. As an example of the problems encountered by the
designer, three different morphological designs of
three-dimensional electrodes are provided: thin-film in FIG. 5A,
columnar shape in FIG. 5B, and a sinusoidal shape in FIG. 5C. The
materials for the three-dimensional electrochemical cells are
copper as anode current collector (101 in FIG. 5A, 108 in FIG. 5B,
113 in FIG. 5C), lithium metal as anode (102 in FIG. 5A, 109 in
FIG. 5B, 114 in FIG. 5C), lithium manganese oxide as cathode (103
in FIG. 5A, 110 in FIG. 5B, 115 in FIG. 5C), polymer
(polyethyleneoxide, PEO) with lithium salts (LiPF.sub.6) as the
electrolyte (104 in FIG. 5A, 111 in FIG. 5B, 116 in FIG. 5C), and
aluminum as cathode current collector (105 in FIG. 5A, 112 in FIG.
5B, 117 in FIG. 5C). Because a polymer electrolyte is used, a
separator is unnecessary. These three electrochemical cells (100,
106, and 112) are produced by physical vapor deposition (PVD)
technique. Hence, the breadloafing is not avoidable. Cell
performance of 100 would not be suitable for high-rate performance
due to the low kinetic properties of LiMn.sub.2O.sub.4 103, such as
the diffusivity of Li+ and electronic conductivity. Therefore,
increasing the surface area of LiMn.sub.2O.sub.4 electrode would
increase LiMn.sub.2O.sub.4 electrode exposure to the electrolyte;
hence, increase the high-rate performance. The morphology of 106
and 112 are two possibilities. By utilizing the computational
technique, described in commonly assigned, co-pending U.S. patent
application Ser. No. 12/484,959, which is hereby incorporated by
reference, as a numerical experiment, it shows that the maximum
stress occurred at the edge, where the LiMn.sub.2O.sub.4, 110,
connect with the current collector, 111 as indicated in FIG. 5D. Of
course, there can be other variations, modifications, and
alternatives.
[0051] While the above is a full description of the specific
embodiments, various modifications, alternative constructions and
equivalents may be used. Therefore, the above description and
illustrations should not be taken as limiting the scope of the
present invention which is defined by the appended claims.
* * * * *