U.S. patent application number 16/702417 was filed with the patent office on 2020-04-02 for hybrid solid-state cell with a sealed anode structure.
This patent application is currently assigned to KERACEL, INC.. The applicant listed for this patent is KERACEL, INC.. Invention is credited to Philip E. ROGREN.
Application Number | 20200106135 16/702417 |
Document ID | / |
Family ID | 67392886 |
Filed Date | 2020-04-02 |
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United States Patent
Application |
20200106135 |
Kind Code |
A1 |
ROGREN; Philip E. |
April 2, 2020 |
HYBRID SOLID-STATE CELL WITH A SEALED ANODE STRUCTURE
Abstract
A monolithic ceramic electrochemical cell housing is provided.
The housing includes two or more electrochemical sub cell housings.
Each of the electrochemical sub cell housing includes an anode
receptive space, a cathode receptive space, a separator between the
anode receptive space and the cathode receptive space, and
integrated electron conductive circuits. A first integrated
electron conductive circuit is configured as an anode current
collector within the anode receptive space. A second integrated
electron conductive circuit is disposed as a cathode current
collector within the cathode receptive space.
Inventors: |
ROGREN; Philip E.; (Santa
Clara, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KERACEL, INC. |
Santa Clara |
CA |
US |
|
|
Assignee: |
KERACEL, INC.
Santa Clara
CA
|
Family ID: |
67392886 |
Appl. No.: |
16/702417 |
Filed: |
December 3, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16262058 |
Jan 30, 2019 |
10535900 |
|
|
16702417 |
|
|
|
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62624476 |
Jan 31, 2018 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 2/08 20130101; H01M
2220/20 20130101; H01M 10/052 20130101; H01M 10/0562 20130101; B29C
64/106 20170801; H01M 10/04 20130101; B33Y 80/00 20141201; H01M
2300/0068 20130101; H01M 2/26 20130101; Y02E 60/10 20130101; B33Y
10/00 20141201; H01M 2/1264 20130101; H01M 2/0207 20130101; H01M
10/0585 20130101; H01M 2/12 20130101; H01M 4/64 20130101 |
International
Class: |
H01M 10/0585 20060101
H01M010/0585; H01M 2/12 20060101 H01M002/12; H01M 2/26 20060101
H01M002/26; H01M 2/08 20060101 H01M002/08; H01M 4/64 20060101
H01M004/64; B33Y 80/00 20060101 B33Y080/00; H01M 2/02 20060101
H01M002/02; H01M 10/052 20060101 H01M010/052; H01M 10/0562 20060101
H01M010/0562; B29C 64/106 20060101 B29C064/106 |
Claims
1. A manufacturing method for assembling a monolithic ceramic
electrochemical cell housing comprising: depositing precursor
materials in a flexible format to form a multi-layer structure; and
heating the multi-layer structure to convert the precursors into a
single monolithic structure void of physical interfaces between
deposited layers.
2. The manufacturing method of claim 1, wherein the flexible format
is fluid, selected from a group consisting of pastes, flowable
powders and green tapes.
3. The manufacturing method of claim 1, wherein depositing the
precursor materials comprises a combination of three dimensional
(3D) printing and laminated tape depositing.
4. The manufacturing method of claim 1, wherein depositing the
precursor materials comprises using additive manufacturing
processes.
5. The manufacturing method of claim 4, wherein the additive
manufacturing processes includes three-dimensional (3D) printing
for each layer of the monolithic ceramic electrochemical cell
housing.
6. The manufacturing method of claim 1, wherein depositing the
precursor materials comprises depositing layers of green (unfired)
tape, prepared to the desires patterns, stacked in the design order
and laminated together.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 16/262,058 entitled "HYBRID SOLID-STATE CELL
WITH A SEALED ANODE STRUCTURE", filed on Jan. 30, 2019, which
claims priority to U.S. Provisional Application No. 62/624,476
entitled "HYBRID SOLID-STATE CELL", filed Jan. 31, 2018, the
contents of which are incorporated by reference in their
entirety.
[0002] The present application is also related to U.S. patent
application Ser. No. 15/883,698, entitled "CERAMIC LITHIUM
RETENTION DEVICE," filed Jan. 30, 2018, the disclosure of which is
hereby incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0003] The present invention relates to a monolithic ceramic
electrochemical cell housing and associated methods of
manufacturing.
BACKGROUND
[0004] Lithium ion batteries (LIBs) provide significant
improvements in energy density and cost per watt hour compared to
the NiCad and Lithium metal hydride cells that preceded them.
Notwithstanding, the manufacturing costs to produce a LIB is cost
prohibitive in electric vehicles. Furthermore, the low energy
density causes our electronic gadgets to be larger and bulkier than
desirable. Recent improvements in the field have attempted to
address these drawbacks by increasing the density of solid-state
cells.
[0005] While cells with lithium metal anodes provide superior
energy density, rechargeable cells cannot be constructed with
lithium metal anodes because of the risk of dendrite formation
during the charge cycle. The dendrite formation during the charge
cycle results in short circuits that cause explosion and combustion
during ignition of the liquid electrolyte. The liquid electrolyte
is a highly combustible organic solvent and does prevent dendrite
growth between the anode and cathode. As a result, LIBs are
typically made up of intercalation anodes, which allow lithium ions
to be inserted into the crystalline structure rather than being
plated onto a current collector. Inserting the lithium ions into
the crystalline structure reduces the effective energy storage
capacity of the anode to less than 10% the theoretical capacity of
lithium metal.
[0006] Liquid electrolyte also limits a maximum voltage for the
battery. Typical liquid electrolytes decompose above four-volts
difference between an anode and a cathode, which effectively limits
the maximum open circuit voltage of LIBs to about 3.8-volts.
Cathode materials that can produce 6 volts against a lithium anode
are considered practical, but not usable in cells with liquid
electrolyte. The ability to use such high voltage cathodes could
increase the energy density of the cells by 50%.
[0007] An obvious solution is to use a nonflammable electrolyte
that resists dendrite formation, is unaffected by potentials above
6 volts, and possesses ionic conductivities equaling or approaching
those of the liquid electrolytes. While ceramics with high lithium
ion conductivities meet those requirements, they also have physical
and chemical properties that prevent practical implementations. For
example, ceramic materials are typically very rigid and brittle.
Furthermore, a practical cell is made up of stacks of sub cells,
each in turn includes very thin layers of the basic components of
an electrochemical cell. Common approaches include constructing a
cell by producing the thin layers (<40 .mu.m for the separator)
in sheets and assembling them in order. However, the thin layers
are fragile and rarely flat, causing a discontinuous contact
between individual layers across the meeting surfaces. Applying
pressure to the stack of layers tends to improve the contact, but
unacceptably increases the risk of fracturing a layer.
[0008] Moreover, applying pressure to the stack of layers fails to
create an integrated connection between layers, rather it creates
pressure contact between two surfaces. Typical battery materials
are chemically active causing the contact to react with the
surrounding environment. In other words, surface contacts, even
between like materials, will be susceptible to increased ionic
and/or electrical resistance at the points of contacts.
[0009] Other drawbacks associated with a cell with lithium metal
anode includes a difficulty in achieving a true hermetic seal
around the anode space. Any oxygen or water ingress into the anode
space will cause oxidation of the lithium, so a non-hermetic seal
reduces the capacity and eventually destroys the cell as oxygen or
water leak into the cell. Although, it is clear liquid electrolyte
poses significant drawbacks, liquid electrolyte is able to flow
into any open space where a lithium atom was oxidized to a lithium
ion and moves across the separator to the cathode, to maintain the
ionic conductivity throughout the cell. Ceramic electrolyte does
not possess this ability. As a result, the conventional approach to
using ceramic electrolyte is to create a planar interface between
the lithium metal and the ceramic cathode. In this way, only a thin
layer of lithium close to the ceramic electrolyte can oxidize and
move into the electrolyte. The result is a very big limitation to
the energy storage capacity of the anode. Thin film solid-state
cells epitomize this drawback because the useable thickness of the
lithium metal anode is only a fraction of the metal deposited.
[0010] There is a need to address the short comings of current
solid-state cell development efforts.
SUMMARY
[0011] A monolithic ceramic electrochemical cell housing is
provided. The housing includes two or more electrochemical sub cell
housings. Each of the electrochemical sub cell housing includes an
anode receptive space, a cathode receptive space, a separator
between the anode receptive space and the cathode receptive space,
and integrated electron conductive circuits. A first integrated
electron conductive circuit is configured as an anode current
collector within the anode receptive space. A second integrated
electron conductive circuit is disposed as a cathode current
collector within the cathode receptive space.
[0012] In some embodiments, the anode receptive spaces are
configured as hermetically sealed volumes, partially filled with
strands of solid-state electrolyte material. The solid-state
electrolyte material includes a high-density ceramic. The
high-density ceramic can be selected from a group consisting of:
borides, carbides, nitrides, phosphides, oxides, selinides,
florides, chlorides, bromides, iodides, or combinations thereof.
The strands of solid-state electrolyte can form a network of
continuous ionic conductivity between the separator and the anode
current collector.
[0013] The strands of electrolyte can occupy between 20% and 80%
volume of the anode receptive spaces. The anode current collector
can serve as current collector for the anode receptive spaces of
the electrochemical sub cell housing and second anode receptive
spaces of a second adjacent electrochemical sub cell housing.
[0014] The cathode receptive spaces can be partially filled with
strands of ceramic material between 1% and 60% volume. In another
embodiment, the cathode receptive spaces can be devoid of ceramic
electrolyte material. The monolithic ceramic electrochemical cell
housing can also include insulating material between each of the
electrochemical sub cell housing.
[0015] The cathode layer can include a seal structure in a filling
aperture configured to contain catholyte. The seal structure can be
configured to isolate the catholyte and provide pressure relief
from the cathode receptive spaces. The anode receptive spaces can
be filled with anode active material during an initial charging
phase.
[0016] The anode receptive spaces can be sealed and the cathode
receptive spaces can be partially sealed. The monolithic ceramic
electrochemical cell housing can also include an anode electrical
contact connecting anode sub-cell current collectors and a cathode
electrical contact connecting cathode sub-cell current
collectors.
[0017] A manufacturing method for assembling a monolithic ceramic
electrochemical cell housing is also provided. The method can
include depositing precursor materials in a flexible format to form
a multi-layer structure. The method can also include heating the
multi-layer structure to convert the precursors into a single
monolithic structure void of physical interfaces between deposited
layers. In some embodiments, the format is fluid, selected from a
group consisting of pastes, flowable powders and green tapes. In
some embodiments, the precursors are deposited using additive
manufacturing techniques.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to describe the manner in which the above-recited
disclosure and its advantages and features can be obtained, a more
particular description of the principles described above will be
rendered by reference to specific examples illustrated in the
appended drawings. These drawings depict only example aspects of
the disclosure, and are therefore not to be considered as limiting
of its scope. These principles are described and explained with
additional specificity and detail through the use of the following
drawings.
[0019] FIG. 1 illustrates an exemplary solid-state cell, in
accordance with an embodiment of the disclosure;
[0020] FIG. 2 illustrates an integrated framework of the exemplary
solid-state cell of FIG. 1, in accordance with an embodiment of the
disclosure;
[0021] FIG. 3 illustrates a sub-cell housing, in accordance with an
embodiment of the disclosure,
[0022] FIG. 4 illustrates a sub-cell housing, in accordance with an
embodiment of the disclosure;
[0023] FIG. 5 illustrates a sub-cell housing, in accordance with an
embodiment of the disclosure;
[0024] FIG. 6 is a flow chart illustrating manufacturing method of
a sub-cell housing, in accordance with an embodiment of the
disclosure;
[0025] FIG. 7 illustrates an alternate integrated framework of the
exemplary solid-state cell of FIG. 1, in accordance with an
embodiment of the disclosure;
[0026] FIG. 8 illustrates an anode layer of the exemplary
solid-state cell of FIG. 1, in accordance with an embodiment of the
disclosure;
[0027] FIG. 9 illustrates a cathode layer of the exemplary
solid-state cell of FIG. 1, in accordance with an embodiment of the
disclosure;
[0028] FIG. 10 illustrates a cell schematic of the exemplary
solid-state cell of FIG. 1, in accordance with an embodiment of the
disclosure; and
[0029] FIG. 11 illustrates a cell schematic of the exemplary
solid-state cell of FIG. 1, in accordance with an embodiment of the
disclosure.
DETAILED DESCRIPTION
[0030] The present invention is described with reference to the
attached figures, where like reference numerals are used throughout
the figures to designate similar or equivalent elements. The
figures are not drawn to scale, and they are provided merely to
illustrate the instant invention. Several aspects of the invention
are described below with reference to example applications for
illustration. It should be understood that numerous specific
details, relationships, and methods are set forth to provide a full
understanding of the invention. One having ordinary skill in the
relevant art, however, will readily recognize that the invention
can be practiced without one or more of the specific details, or
with other methods. In other instances, well-known structures or
operations are not shown in detail to avoid obscuring the
invention. The present invention is not limited by the illustrated
ordering of acts or events, as some acts may occur in different
orders and/or concurrently with other acts or events. Furthermore,
not all illustrated acts or events are required to implement a
methodology in accordance with the present invention.
[0031] In view of the foregoing, embodiments disclosed herein are
directed to an apparatus and a manufacturing process for producing
a monolithic ceramic electrochemical cell housing. The monolithic
ceramic electrochemical cell housing are produced at a per watt
costs below current lithium ion batteries (LIBs). The volumetric
energy densities are significantly higher than current LIBs, and in
capacities ranging from a few milliwatt hours to kilowatt hours. In
some embodiments, multi-material additive processes are
incorporated to assemble the cells from precursors of the final
materials, and convert the precursors to their final properties
when the assembly is complete. These multi-material additive
processes are implemented to eliminate the drawbacks of assembling
cells from ceramic sheets with their final properties. The
precursors can be in a fluid or plastically deformable sheet state,
which can be layered and bonded together as precursors. The
precursors in this state are also easy to handle and form into the
desired configuration.
[0032] As a result, after the conversion to the final properties
the resulting structure is a monolithic block with no discernable
interface where adjacent layers were joined. The interface of the
layers of dissimilar precursor materials is designed chemically and
physically to optimize the conductivity between the two final
materials. Specifically, a true chemical bond can be formed at the
interface, avoiding the possibility of uncontrolled reactions with
the environment or incomplete contact between materials will
compromise the desired properties of the interface. Conversion of
the precursors in some embodiments include heat treatment processes
that remove organic material components of the precursors, convert
the remaining constituents to the final desired chemistry, and
sinter the final materials to their respective density targets.
[0033] The disclosed multi-material additive processes also produce
a design that allows the liquid electrolyte to maintain ionic
conductivity completely across an electrode space regardless of the
state of charge. For examples, a porous structure of electrolyte
can be created across an anode space, which forms a fully
interconnected web of ionic conductive material from the solid
electrolyte separator to the current collector of the electrode.
The porous structure can be configured such that the distance
between adjacent portions of the ionically conductive web is less
than two-times the maximum distance an ion can be transferred into
the ionically conductive electrolyte.
[0034] The disclosed multi-material additive processes also provide
a cost-effective configuration of a hybrid cell design that
incorporates a cathode with a similar composition to the typical
cathodes employed in conventional lithium ion cells, and an anode
that it is a hermetically sealed space. Specifically, the anode can
be bounded by the current collector on one side, the separator on
the opposite side, filled with the ionically conductive porous
structure, and void of any intercalation host or active charge
transfer species immediately following manufacture of the cell
structure. The active charge transfer species (e.g., lithium) can
be introduced to the anode space by plating lithium from the
cathode to the anode current collector during the conditioning, or
first charging of the cell.
[0035] FIG. 1 illustrates an exemplary solid-state cell 100 in
accordance with an embodiment of the disclosure. The general
structure of the solid-state cell 100 can include a monolithic and
highly integrated framework 102, as illustrated in FIG. 2. The
integrated framework 102 can include one to thousands of stacked
sub cells housings 80.
[0036] Referring to FIG. 2, each sub-cell housing 80, with
alternating thin layers, can include an anode receptive space 41
and a cathode receptive space 11. The anode receptive space 41 and
cathode receptive space 11 can be separated by a thin separator 30,
which may be made up of solid-state electrolyte. Each anode
receptive space 41 can be made up of a hermetically sealed, defined
volume, partially filled with strands of solid-state electrolyte
material (shown in FIG. 3 as 32).
[0037] Referring to FIG. 3, the hermetically sealed, defined
volume, partially filled with strands of solid-state electrolyte
material 32 form a region of controlled porosity (referred to
herein as the "empty space 42"). The solid-state electrolyte
material 32 can include a high-density ceramic. For the purposes of
this example, the high-density ceramic can include, but is not
limited to, borides, carbides, nitrides, phosphides, oxides,
selinides, florides, chlorides, bromides, iodides, or combinations
of thereof. The high-density ceramic can include any ceramic that
exhibits room temperature conductivities of the intended charge
transfer ion of the specific battery design, greater than
1.times.10.sup.-6 S/cm. In some embodiments, the charge transfer
ion is Li.sup.+. In alternative embodiments, the charge transfer
ion can be either Na.sup.+, Mg.sup.+2, K.sup.+, and Al.sup.+3.
[0038] The strands of solid-state electrolyte 32 can form a network
of continuous ionic conductivity between the separator 30 and the
anode current collector 50. The porous electrolyte structure can be
made from solid-state electrolyte material, similar to the
separator 30, but with a controlled structure. Continuous strands
of electrolyte can be surrounded by the empty space 42 and extend
from the separator 30 and the current collector 50. The empty space
42 can also extend from the separator 30 to the anode current
collector 50. In some embodiments, the strands of electrolyte can
occupy between 20% and 80% of the volume of the anode receptive
space 41 (also shown in FIG. 2) while the void space occupies the
remaining volume. In some embodiments, the porous structure is
designed such that the average distance between adjacent strands of
electrolyte material can be between 0.000001 mm and 0.040 mm.
Referring back to FIG. 2, the anode receptive spaces 41 for two
adjacent sub cell housings 98 can be juxtaposed, separated by the
current collector 50. The current collector 50 can serve as current
collector for both anode receptive spaces 41 of the two adjacent
sub cell housings 80.
[0039] Each cathode receptive space 11 can also be a defined volume
partially filled with strands of ceramic material. In some
embodiments, the cathode receptive space 11 can form a region of
controlled porosity. In other embodiments, the cathode receptive
space 11 can be an open defined volume free of any ceramic
material. In some embodiments, strands of electrolyte material in
the cathode receptive space 11 can occupy from 0% to 60% of the
total volume. Furthermore, the strands of electrolyte material can
be designed such that the average distance between adjacent strands
of electrolyte material can be between 0.02 mm and 200 mm.
[0040] The strands of ceramic material can include solid state
electrolyte material that provides ionic conductivity across the
thickness of the cathode space similar to the porous structure in
the anode receptive space 41. Alternatively, the ceramic strands
can be provided as mechanical elements to control the precise
thickness of the cathode receptive space 11.
[0041] In some embodiments, the cathode receptive spaces 11 of two
adjacent sub cell housings 80 can be configured such that one
cathode receptive space serves said two adjacent sub cell housings
80. Referring momentarily to the cathode current collectors 20 in
FIG. 2 and FIG. 11. Each of the two adjacent sub cells can be
configured with an electron conductive layer directly on the
cathode side of the separators 30. The cathode receptive space 11
(shown in FIG. 11) of the two sub cell housings can be bounded on
either side by cathode current collectors 20 of the two adjacent
cell housings. The distance between the separators 30 of the two
adjacent sub cell housings can be calculated to create a cathode
receptive space 11 volume that includes an amount of catholyte that
meets the design parameters of the two adjacent sub cells.
[0042] Referring back to FIG. 2, the cathode receptive space 11 can
be further defined by low porosity ceramic walls 46 extending
between the separators 30 to create a seal between the separators
30. The ceramic walls (shown in FIG. 9 as 46) can extend around at
least 60% of the periphery of the cathode receptive space 11. The
low porosity ceramic can be made up of solid-state electrolyte.
[0043] With reference to FIG. 7, in some embodiments, each sub-cell
housing 80 can be separated from surrounding sub-cell housings 80
by layers of insulating material 25. The insulating material can be
disposed between the separators of adjacent sub cell housings, at a
calculated distance. The distance can be calculated to create
cathode receptive space 11 volume and anode receptive space 41
volume to contain an amount of catholyte and charge transfer
species. The amount of catholyte and charge transfer species are
designed to meet the configuration parameters of the sub-cell 80.
In these embodiments, current collectors can be disposed on the
surfaces of the layer of insulating material 25 or anywhere within
the cathode receptive space 11.
[0044] FIG. 3 illustrates a sub-cell housing 80, in accordance with
an embodiment of the disclosure. Each sub-cell housing 80 is a
layered structure, which can include solid-state electrolyte with
alternating layers of high density electrolyte material. The
sub-cell housing 80 also can include layers with a high degree of
controlled porosity. The layers include anode layers 44, cathode
layers 10, and separator layers 30. The anode and cathode layers
can be made up of high porosity while the separator layers can be
made up of high density electrolyte. The anode layers 44 can
include anode receptive spaces 41, low porosity boarders 60 (Shown
in FIG. 8), and anode current collectors 50. The cathode layers 10
can be made up of cathode receptive space 11, low porosity boarder
46 and a filling aperture 49 (Shown in FIG. 9). The low porosity
border 46 can be made up of high density ceramic material. In some
embodiments, the high density ceramic material can include
solid-state electrolyte. The low porosity border 60 completely and
hermetically seals the anode receptive spaces 41 from the
environment. The low porosity border 46 can also partially surround
the cathode receptive spaces 11, physically isolating the cathode
receptive space from other layers in the sub-cell housing.
[0045] Referring back to FIG. 3, the separators 30 are configured
to separate the anode receptive space 41 of each sub-cell housing
from the cathode receptive space 11 of each sub-cell to eliminate
contact between the spaces. The separator layer 30 can be
configured with a precise thickness to ensure it is void of open
pores. In a preferred embodiment, the thickness of the separator
layer can be range between 0.00001 mm to 1.0 mm. The thickness of
the anode receptive space 41 and cathode receptive space 11 can be
configured to optimize the performance of the specific materials.
The configuration of the open volume and the solid-state
electrolyte strands are also designed to optimize the performance
of the specific materials.
[0046] As indicated above, the cathode layers 10 can include
cathode receptive space 11 partially or completely filled with
catholyte. The low porosity ceramic walls can be positioned around
at least a portion of the cathode receptive space 11 and the
cathode current collectors 20 within the cathode receptive
space.
[0047] The cathode layer 10 can also include a seal structure in a
filling aperture 49 (shown in FIG. 2 and FIG. 9) configured to
contain the catholyte. The seal structure can be configured to
protect the catholyte from the environment and provide pressure
relief from the cathode receptive space 11. The separator layer 30
can include electrically insulated ceramic material. In some
embodiments, at least a central portion of the electrically
insulated ceramic material includes solid-state electrolyte
appropriate for the design charge transfer species of the sub-cell.
The low porosity ceramic walls can also include solid-state
electrolyte material and serve as protective packaging for the
sub-cell.
[0048] In a preferred embodiment, the multilayered structure of
anode receptive space 41, the cathode receptive space 11, the
separators 30 and the current collectors 50 and 20 can be assembled
without either catholyte or anode active materials present. The
catholyte material can be inserted through the filling aperture 49
(shown in FIG. 2 and FIG. 9) and sealed in place in the cathode
layer 10. The catholyte material can be made up of cathode active
material, an electrolyte for the charge transfer ion of the
sub-cell, and an electron conducting material. The electron
conducting material can include carbon, a metal or an electron
conductive ceramic. The cathode active material can be made up of
an intercalation host material suitable for the charge transfer
ion.
[0049] Referring specifically to FIG. 5, the empty space 42 of the
porous anode receptive space 41 can be partially filled with anode
active material 43 during the initial charging of the battery. In
some embodiments, the anode active material 43 can include lithium
metal. The anode active material can be electro plated onto the
anode current collector to initiate the filling of the anode
receptive space 41. The anode active material can then be electro
plated onto the previously plated anode active material until the
anode receptive space 41 fills with the anode active material
43.
[0050] The catholyte material can be inserted in the cathode
receptive space 10 by converting the catholyte material to a fluid
and drawing the fluid material into the porous structure under
vacuum force. In some embodiments, converting the catholyte
materials to a fluid can include melting the catholyte materials,
compounding the catholyte materials into a mixture of solid and
liquid materials, dissolving the catholyte materials in a solvent,
or converting the catholyte materials to a fine powder. In an
alternative embodiment, the catholyte material can be configured as
solid or semi solid structure. The structure can be shaped to
precisely fit the cathode receptive spaces. In this embodiment, the
catholyte material structures can directly inserted and secured in
the respective cathode receptive spaces.
[0051] The sub-cell can be configured to enable the introduction of
the catholyte material into the cathode receptive spaces, without
damaging the rest of the structure. For example, the sub-cell can
be configured such that all cathode receptive spaces are sealed
continuously along at least three quarters of the edges of the
sheet like volume, by low porosity ceramic walls 46. In some
embodiments, the cathode receptive spaces are open from over
1/1,000 to 1/2 of the total circumference. In some embodiments, the
cathode receptive spaces are open at a first location of the stack
of cell layers. The first location enables the filling aperture of
the cathode receptive spaces to be immersed into a fluid catholyte
material. In some embodiments, the filling aperture can be fully
immersed in the fluid catholyte material.
[0052] Further, the sub-cell includes an anode electrical contact
92 of FIG. 10 and FIG. 11, connecting all of the anode sub cell
current collectors. The anode electrical contact can include an
extension for making electrical contact on the outside of the
sub-cell. The sub-cell also includes a cathode electrical contact
94 of FIG. 10 and FIG. 11, connecting all of the cathode sub cell
current collectors. The cathode electrical contact can also include
an extension accessible for making electrical contact on the
outside of the sub-cell.
[0053] In some embodiments, the electrolyte structure is the basic
framework and exoskeleton of the solid-state cell 100. A continuous
electrolyte is required within the anode region to transport
lithium ions to and from electron conductive sites. The solid-state
electrolyte can also serve as the separator 30 between anode and
cathode regions, as a fully dense ceramic structure preventing
growth of lithium dendrites during a cell charging cycle. In the
anode and cathode regions, the electrolyte can form a porous
structure that emulates a liquid electrolyte, allowing ion transfer
throughout the three-dimensional space regardless of the state of
charge. The electrolyte structure can seal the edges of the
electrode regions, effectively completing a package around the
sub-cell. The result is a structure of alternating dense and porous
layers, integrated as a continuous structure throughout the cell
with no apparent discontinuity at the interface of layers of
similar material. At interfaces of chemically dissimilar materials,
properties of the dissimilar materials are configured such that the
only discontinuity at such interfaces is in the chemical
composition of the interfacing layers.
[0054] In some embodiments, assembly of the solid-state cell
structure is accomplished by sequential deposition of layers or
partial layers. The deposition of layers or partial layers can be
patterned appropriately for the function of the individual layers,
as precursors of the desired final materials. The precursors
include mixtures of materials that form desired high density and
electrochemical properties after a heat treatment. The mixture of
materials can also act to bind the precursor materials in the
predetermined configuration. The binding materials can be separate
materials from those that form the desired end material. In this
case, the binding materials are removed from the structure during
the heat-treating process. In other embodiments, the binding
materials can form the desired end material and have binding
properties.
[0055] FIG. 6 is a flow chart illustrating the manufacturing
process of a sub-cell housing. At step 601, the precursor materials
are deposited in formats which are highly flexible and not brittle.
For example, the precursor materials can be deposited as a fluid,
including sheets which are easily plastically deformed without
sacrificing the integrity of the sheet. The fluids can include
pastes, flowable powders and green tapes. It should be understood
that the precursors can be deposited in one format or a combination
of two or more formats. After all the layers of the cell structure
are deposited, the completed structure can be heat treated to
convert the precursors to the desired physical and electrochemical
properties at Step 602. Furthermore, the heat treatment creates a
single monolithic structure with no physical interfaces between the
deposited layers.
[0056] In some embodiments, the precursors can be deposited using
additive manufacturing techniques. For example, the precursors can
be deposited using a three-dimensional (3D) printer accompanied by
a computer system and guided by CAD data for each layer of the
structure. In alternative embodiments, the precursors can be
deposited as layers of green (unfired) tape, prepared to the
desired patterns, stacked in the design order and laminated
together. In alternative embodiments, both 3D printing and
laminated tape deposition processes can be incorporated to form the
complete structure.
[0057] Although the cathode contains organic liquid electrolyte,
the overall volume of liquid in the solid-state cell is about 10%
of that in a standard LIB. This reduction of liquid greatly reduces
the explosion and fire potential of the solid-state cell 100
compared to a standard LIB.
[0058] While some embodiments have been shown and described, it
will be obvious to those skilled in the relevant arts that changes
and modifications may be made without departing from the invention
in its broader aspects. Therefore, the aim in the appended claims
is to cover all such changes and modifications that fall within the
true spirit and scope of the invention. The matter set forth in the
foregoing description and accompanying drawings is offered by way
of illustration only and not as a limitation. The actual scope of
the invention is intended to be defined in the following claims
when viewed in their proper perspective based on the prior art.
[0059] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to limit the
invention. As used herein, the singular forms "a," "an," and "the"
are intended to include the plural forms as well, unless the
context clearly indicates otherwise. Furthermore, to the extent
that the terms "including," "includes," "having," "has," "with," or
variants thereof are used in either the detailed description and/or
the claims, such terms are intended to be inclusive in a manner
similar to the term "comprising."
[0060] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. Furthermore, terms, such as those defined in
commonly used dictionaries, should be interpreted as having a
meaning that is consistent with their meaning in the context of the
relevant art, and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
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