Description:FIELD OF INVENTION
[001] The subject matter of the present disclosure broadly relates to the field of battery,
preferably lithium-ion battery. Particularly, the present disclosure relates to electrolyte filling
methods for lithium-ion battery cells.
5 BACKGROUND OF THE INVENTION
[002] Lithium-ion batteries have revolutionized portable electronics by providing a
lightweight, high-capacity power source, largely owing to their exceptional energy density,
extensive cycle life, and minimal self-discharge. The movement of lithium ions, which shuttle
back and forth between the cathode and anode during charging and discharging cycles is the
10 most crucial functionality. This ion migration occurs through an electrolyte medium, which
acts as a conductive pathway while simultaneously ensuring the electrochemical stability of
the entire system. The electrolyte's composition, which is a lithium salt dissolved in an organic
solvent must allow for efficient ion conduction, prevent electronic conductivity that could
cause short circuits, and remain stable over a wide voltage range and temperature spectrum.
15 The quality and properties of the electrolyte are therefore pivotal in determining the battery's
performance, safety, and longevity, making it a critical component in the design and
optimization of lithium-ion battery technology.
[003] The process of filling lithium-ion battery cells with electrolyte is a critical yet intricate
step in manufacturing that significantly impacts the overall performance and reliability of the
20 battery. Traditional methods typically involve multiple filling cycles, each followed by a
soaking period designed to ensure thorough permeation of the electrolyte into the porous
electrode materials and separator layers. This multi-step approach aims to achieve complete
wetting, which is essential for optimal ionic conductivity and uniform electrochemical
behaviour across the cell. However, the extended duration of these repeated cycles can hinder
25 large-scale production efficiency, reducing throughput and increasing manufacturing costs.
Moreover, the repeated handling increases the risk of electrolyte spillage, contamination, and
material wastage, all of which can compromise product quality and safety.
[004] In addition to time and safety concerns, conventional filling techniques often struggle
to ensure uniform electrolyte distribution, especially in larger-format cells or those with
30 densely packed electrodes. Non-uniform wetting can lead to regions within the cell that have
insufficient ionic pathways, resulting in decreased capacity, higher internal resistance, and
accelerated capacity fade over time. Another significant challenge is the formation of trapped
air pockets or voids within the cell structure during filling, which can create localized areas of
2
poor ion conductivity. These air pockets not only impair initial performance but can also cause
long-term degradation, as they promote uneven current distribution and mechanical stress.
[005] Hence, there is a need in the art for advanced filling economically significant methods
capable of achieving full, uniform electrolyte saturation while minimizing defects, thereby
enhancing t 5 he longevity and safety of lithium-ion batteries.
SUMMARY OF THE INVENTION
[006] In a first aspect of the present disclosure, there is provided a method for electrolyte
filling for a lithium-ion battery cell, the method comprising: (i) degassing the battery cell at a
pressure in a range of 0 kPa to 5 kPa; (ii) applying a high pressure at a range of 20 kPa to 50
10 kPa to fill the electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -
40 kPa to -90 kPa to create an internal vacuum in the battery-cell; (iv) optionally, applying high
vacuum at a pressure in a range of -70 kPa to -90 kPa; and (v) applying pressure in a range of
15 kPa to 30 kPa for complete electrolyte filling into the cell.
[007] In a second aspect of the present disclosure, there is provided a lithium-ion battery cell
15 filled with electrolyte using the method as disclosed herein.
[008] These and other features, aspects, advantages of the present subject matter will be better
understood with reference to the following description and appended claims. This summary is
provided to introduce a selection of concepts in a simplified form. This summary is not intended
to identify key features or essential features of the claimed subject matter, nor is it intended to
20 be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] The following drawings form a part of the present specification and are included to
further illustrate aspects of the present disclosure. The disclosure may be better understood by
reference to the drawings in combination with the detailed description of the specific
25 embodiments presented herein.
[010] Figure 1 depicts computed tomography (CT) scan results for (a) multi-shot electrolyte
filling process; (b) two-shot electrolyte filling process; and (c) single-shot electrolyte filling
process, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
30 [011] Those skilled in the art will be aware that the present disclosure is subject to variations
and modifications other than those specifically described. It is to be understood that the present
3
disclosure includes all such variations and modifications. The disclosure also includes all such
steps, features, compositions, and compounds referred to or indicated in this specification,
individually or collectively, and any and all combinations of any or more of such steps or
features.
5 Definitions
[012] For convenience, before further description of the present disclosure, certain terms
employed in the specification, and examples are delineated here. These definitions should be
read in the light of the remainder of the disclosure and understood as by a person of skill in the
art. The terms used herein have the meanings recognized and known to those of skill in the art,
10 however, for convenience and completeness, particular terms and their meanings are set forth
below.
[013] The articles “a”, “an” and “the” are used to refer to one or to more than one (i.e., to at
least one) of the grammatical object of the article.
[014] The terms “comprise” and “comprising” are used in the inclusive, open sense, meaning
15 that additional elements may be included. It is not intended to be construed as “consists of
only”.
[015] Throughout this specification, unless the context requires otherwise the word
“comprise”, and variations such as “comprises” and “comprising”, will be understood to imply
the inclusion of a stated element or step or group of elements or steps but not the exclusion of
20 any other element or step or group of elements or steps.
[016] The term “including” is used to mean “including but not limited to”. “Including” and
“including but not limited to” are used interchangeably.
[017] The term “electrolyte filling” refers to the process of introducing the conductive
medium into the cell to facilitate the movement of lithium ions between the cathode and anode
25 during charge and discharge cycles.. This step is crucial for enabling efficient ion transport,
which directly impacts the battery’s performance, capacity, and lifespan.
[018] The term "degassing" refers to the process of removing gases from the battery cell,
typically performed under low pressure conditions to extract trapped air or other gaseous
components from within the cell structure. In an aspect of the present disclosure, degassing of
30 the battery cell is carried out at a pressure in a range of 0 kPa to 5 kPa, where 0 kPa corresponds
to atmospheric pressure.
[019] The term "high pressure" in the context of electrolyte filling refers to the application of
pressure significantly above atmospheric pressure to force electrolyte into the porous structures
4
of the battery cell components. In an aspect of the present disclosure, to fill the electrolyte into
the battery cell, high pressure is applied at a range of 20 kPa to 50 kPa.
[020] The term "low vacuum" describes a state of reduced pressure that is moderately below
atmospheric pressure, used to create a partial vacuum within the battery cell to facilitate
electrolyte penetration. In an aspect of the present 5 disclosure, to create an internal vacuum in
the battery-cell, low vacuum is applied at a range of -40 kPa to -90 kPa.
[021] The term "high vacuum" refers to a state of very low pressure, approaching a nearcomplete
vacuum, used to remove residual gases and ensure thorough electrolyte distribution.
In an aspect of the present disclosure, high vacuum is applied at a pressure in a range of -70
10 kPa to -90 kPa.
[022] The term “single filling” refers to the process of introducing the electrolyte into a
battery cell in one continuous and complete step, rather than multiple partial fills or iterative
injections. It ensures that the electrolyte is uniformly distributed throughout the cell's internal
components in a single operation, which helps to minimize the risk of air entrapment, uneven
15 wetting, or contamination.
[023] The term "injection cycles" refer to the discrete instances of introducing electrolyte into
the battery cell during the filling process. In an aspect of the present disclosure, the electrolyte
is injected into the lithium-ion battery cell in 15 to 16 injection cycles during the single filling
cycle.
20 [024] The term "electrolyte" refers to the ionically conductive medium in a lithium-ion
battery that facilitates the movement of lithium ions between the cathode and anode during
charge and discharge cycles.
[025] The term "lithium-ion battery cell" refers to an electrochemical cell or a combination
of electrochemical cells wherein the cell undergoes chemical reactions that get converted and
25 stored as electrical energy.
[026] The term "cylindrical cell" refers to a type of lithium-ion battery cell that has a
cylindrical shape, typically characterized by a tubular metal casing that houses the electrode
assembly and electrolyte. It is a specific geometry of lithium-ion battery where the electrodes
and separator are rolled into a cylindrical shape and enclosed in a cylindrical casing. In an
30 aspect the present disclosure, cylindrical cell is selected from wet NMC, dry NMC, wet
LiFePO4 without core tube..
[027] The term “cathode” refers to the positive terminal where ions gain electrons (are
reduced) during discharge. In an aspect of the present disclosure, cathode is selected from
layered metal oxides, spinel metal oxides or olivine phosphates.
5
[028] The term "layered metal oxides" refers to a class of cathode materials with a layered
crystal structure, typically including compounds such as lithium cobalt oxide (LiCoO2) or
lithium nickel manganese cobalt oxide (NMC).
[029] The term "spinel metal oxides" refers to a cathode material with a three-dimensional
cubic crystal structure, known as 5 the spinel structure, which follows the general formula
AB₂O₄, such as lithium manganese oxide (LiMn2O4). In this structure, metal cations occupy
specific sites within an oxygen anion framework, resulting in a highly stable and conductive
material.
[030] The term "olivine phosphates" refers to cathode materials with an olivine crystal
10 structure, which has the general formula LiMPO₄, where M typically represents transition
metals such as iron, manganese, or cobalt, the most common being lithium iron phosphate
(LiFePO4).
[031] The term “anode” refers to the electrode where lithium or other ions are released
(oxidized) during discharge, and it typically serves as the negative terminal. In an aspect of the
15 present disclosure, anode is selected from graphite, silicon, silicon-carbon composites, or
Lithium Titanate Oxide (LTO).
[032] Ratios, concentrations, amounts, and other numerical data may be presented herein in
a range format. It is to be understood that such range format is used merely for convenience
and brevity and should be interpreted flexibly to include not only the numerical values
20 explicitly recited as the limits of the range, but also to include all the individual numerical
values or sub-ranges encompassed within that range as if each numerical value and sub-range
is explicitly recited.
[033] Unless defined otherwise, all technical and scientific terms used herein have the same
meaning as commonly understood by one of ordinary skills in the art to which this disclosure
25 belongs. Although any methods and materials similar or equivalent to those described herein
can be used in the practice or testing of the disclosure, the preferred methods, and materials are
now described. All publications mentioned herein are incorporated herein by reference.
[034] The present disclosure is not to be limited in scope by the specific embodiments
described herein, which are intended for the purposes of exemplification only. Functionally
30 equivalent products, and methods are clearly within the scope of the disclosure, as described
herein.
[035] As discussed in the background, conventional methods for electrolyte filling in lithiumion
battery cells often involve multi-shot or two-shot processes, which are time-consuming and
may lead to inconsistent electrolyte distribution. These methods typically require multiple
6
filling cycles and extended soaking periods, resulting in low production rates and potential
electrolyte wastage. Additionally, the prolonged exposure of battery components to air during
these processes may introduce impurities and affect cell performance. Therefore, the present
disclosure addresses these limitations by introducing a single-shot electrolyte filling process
for lithium-ion battery cells. This method significantly 5 reduces filling time, increases
production efficiency, and ensures uniform electrolyte distribution throughout the cell. By
optimizing vacuum and pressure parameters, the process achieves complete electrolyte filling
in a single cycle, eliminating the need for multiple filling and soaking steps.
[036] Accordingly, the present disclosure provides a method for electrolyte filling for a
10 lithium-ion battery cell, the method comprising: (i) degassing the battery cell at a pressure in a
range of 0 kPa to 5 kPa; (ii) applying a high pressure at a range of 20 kPa to 50 kPa to fill the
electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -40 kPa to -90
kPa to create an internal vacuum in the battery-cell; (iv) optionally, applying high vacuum at a
pressure in a range of -70 kPa to -90 kPa and (v)applying pressure in a range of 15 kPa to 30
15 kPa for complete electrolyte filling into the cell.
[037] In an embodiment of the present disclosure, there is provided a method for electrolyte
filling for a lithium-ion battery cell, the method comprising: (i) degassing the battery cell at a
pressure in a range of 0 kPa to 5 kPa; (ii) applying a high pressure at a range of 20 kPa to 50
kPa to fill the electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -
20 40 kPa to -90 kPa to create an internal vacuum in the battery-cell; (iv) optionally, applying high
vacuum at a pressure in a range of -70 kPa to -90 kPa and (v) applying pressure in a range of
15 kPa to 30 kPa for complete electrolyte filling into the cell. In another embodiment of the
present disclosure, the method comprising: (i) degassing the battery cell at a pressure in a range
of 2 kPa to 4 kPa; (ii) applying a high pressure at a range of 25 kPa to 35 kPa to fill the
25 electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -60 kPa to -89
kPa to create an internal vacuum in the battery-cell; (iv) optionally, applying high vacuum at a
pressure in a range of -75 kPa to -88 kPa; and (v) applying pressure in a range of 19 kPa to 25
kPa for complete electrolyte filling into the cell.
[038] In an embodiment of the present disclosure, there is provided a method as disclosed
30 herein, wherein the method comprises applying a vacuum pressure to the battery cell in a range
of -70 kPa to -90 kPa, prior to the step (i). In another embodiment of the present disclosure, the
method comprises applying a vacuum pressure to the battery cell in a range of -75 kPa to -88
kPa, prior to the step (i).
7
[039] In an embodiment of the present disclosure, there is provided a method for electrolyte
filling for a lithium-ion battery cell, the method comprising: (i) applying a vacuum pressure to
the battery cell in a range of -70 kPa to -90 kPa; (ii) degassing the battery cell at a pressure in
a range of 0 kPa to 5 kPa; (iii) applying a high pressure at a range of 20 kPa to 50 kPa to fill
the electrolyte into the battery cell; (iv) applying a 5 low vacuum step at a range of -40 kPa to -
90 kPa to create an internal vacuum in the battery-cell; (v) optionally, applying high vacuum
at a pressure in a range of -70 kPa to -90 kPa and (vi) applying pressure in a range of 15 kPa
to 30 kPa for complete electrolyte filling into the cell.
[040] In an embodiment of the present disclosure, there is provided a method as disclosed
10 herein, wherein the steps (ii) and (iii) are repeated for 2-3 times.
[041] In an embodiment of the present disclosure, there is provided a method for electrolyte
filling for a lithium-ion battery cell, the method comprising: (i) degassing the battery cell at a
pressure in a range of 0 kPa to 5 kPa; (ii) applying a high pressure at a range of 20 kPa to 50
kPa to fill the electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -
15 40 kPa to -90 kPa to create an internal vacuum in the battery-cell; (iv) optionally, applying high
vacuum at a pressure in a range of -70 kPa to -90 kPa and (v) applying pressure in a range of
15 kPa to 30 kPa for complete electrolyte filling into the cell, wherein the steps (ii) and (iii) are
repeated for 2-3 times.
[042] In an embodiment of the present disclosure, there is provided a method as disclosed
20 herein, wherein the steps (i) to (iv) are maintained for a time period in a range of 20 seconds to
60 seconds. In another embodiment of the present disclosure, the steps (i) to (iv) are maintained
for a time period in a range of 30 seconds to 55 seconds.
[043] In an embodiment of the present disclosure, there is provided a method for electrolyte
filling for a lithium-ion battery cell, the method comprising: (i) degassing the battery cell at a
25 pressure in a range of 0 kPa to 5 kPa for a time period in a range of 30 seconds to 60 seconds;
(ii) applying a high pressure at a range of 20 kPa to 50 kPa to fill the electrolyte into the battery
cell; (iii) applying a low vacuum step at a range of -40 kPa to -90 kPa to create an internal
vacuum in the battery-cell; (iv) applying high vacuum at a pressure in a range of -70 kPa to -
90 kPa for a time period in a range of 30 seconds to 60 seconds; and (v) applying pressure in a
30 range of 15 kPa to 30 kPa for complete electrolyte filling into the cell.
[044] In an embodiment of the present disclosure, there is provided a method as disclosed
herein, wherein the method comprises filling the electrolyte in a single filling cycle.
8
[045] In an embodiment of the present disclosure, there is provided a method as disclosed
herein, further comprising injecting electrolyte into the lithium-ion battery cell in 15 to 16
injection cycles during the single filling cycle.
[046] In an embodiment of the present disclosure, there is provided a method as disclosed
herein, wherein the cell contains 35 to 45 5 grams of electrolyte. In another embodiment of the
present disclosure, the cell contains 36 to 40 grams of electrolyte.
[047] In an embodiment of the present disclosure, there is provided a method as disclosed
herein, wherein the method results in electrolyte filling of 10 to 20 cells per hour.
[048] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
10 filled with electrolyte using the method as disclosed herein.
[049] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
filled with electrolyte using the method as disclosed herein, wherein the method comprising:
(i) degassing the battery cell at a pressure in a range of 0 kPa to 5 kPa for a time period in a
range of 20 seconds to 60 seconds; (ii) applying a high pressure at a range of 20 kPa to 50 kPa
15 to fill the electrolyte into the battery cell; (iii) applying a low vacuum step at a range of -40
kPa to -90 kPa to create an internal vacuum in the battery-cell; (iv) optionally applying high
vacuum at a pressure in a range of -70 kPa to -90 kPa for a time period in a range of 30 seconds
to 60 seconds; and (v) applying pressure in a range of 15 kPa to 30 kPa for complete electrolyte
filling into the cell.
20 [050] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
as disclosed herein, wherein the cell is a cylindrical cell.
[051] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
as disclosed herein, wherein the cell contains 35 to 45 grams of electrolyte. In another
embodiment of the present disclosure, the cell contains 36 to 42 grams of electrolyte.
25 [052] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
as disclosed herein, wherein the cell comprises cathode selected from layered metal oxides,
spinel metal oxides or olivine phosphates and anode selected from graphite, silicon, siliconcarbon
composites, or lithium titanate oxide (LTO).
[053] In an embodiment of the present disclosure, there is provided a lithium-ion battery cell
30 as disclosed herein, wherein the cell exhibits no electrolyte spillage after the single filling cycle.
[054] In an embodiment of the present disclosure, there is provided an apparatus for
electrolyte filling for a lithium-ion battery cell, the apparatus comprising: (a) a vacuum system
configured to apply a vacuum pressure in a range of -70 kPa to -90 kPa; (b) a pressure system
configured to apply a high pressure in a range of 15 to 30 kPa; (c) a control system configured
9
to perform a filling cycle comprising the steps of: (i) degassing the battery cell at a pressure in
a range of 0 kPa to 5 kPa for a time period in a range of 20 seconds to 60 seconds; (ii) applying
a high pressure at a range of 20 kPa to 50 kPa to fill the electrolyte into the battery cell; (iii)
applying a low vacuum step at a range of -40 kPa to -90 kPa to create an internal vacuum in
the battery-cell; (iv) optionally applying high vacuum at 5 a pressure in a range of -70 kPa to -
90 kPa for a time period in a range of 30 seconds to 60 seconds; and (v) applying pressure in a
range of 15 kPa to 30 kPa for complete electrolyte filling into the cell.
[055] In an embodiment of the present disclosure, there is provided an apparatus as disclosed
herein, wherein the apparatus performs the electrolyte filling in a single filling cycle.
10 [056] In an embodiment of the present disclosure, there is provided an apparatus as disclosed
herein, wherein the apparatus further comprises an injection system configured to inject
electrolyte in 15 to 16 injection cycles during the single filling cycle.
[057] In an embodiment of the present disclosure, there is provided an apparatus as disclosed
herein, wherein the apparatus is adapted to uniformly fill the battery cell with electrolyte and
15 minimizing trapped gases.
[058] In an embodiment of the present disclosure, there is provided an apparatus as disclosed
herein, wherein the cell contains 35 to 45 grams of electrolyte. In another embodiment of the
present disclosure, the cell contains 36 to 40 grams of electrolyte.
[059] embodiment of the present disclosure, there is provided an apparatus as disclosed
20 herein, wherein the method results in electrolyte filling of 10 to 20 cells per hour.
[060] Although the subject matter has been described in considerable detail with reference to
certain examples and implementations thereof, other implementations are possible.
EXAMPLES
[061] The disclosure will now be illustrated with following examples, which is intended to
25 illustrate the working of disclosure and not intended to take restrictively to imply any
limitations on the scope of the present disclosure. Unless defined otherwise, all technical and
scientific terms used herein have the same meaning as commonly understood to one of ordinary
skill in the art to which this disclosure belongs. Although methods and materials similar or
equivalent to those described herein can be used in the practice of the disclosed methods and
30 materials, the exemplary methods, devices, and materials are described herein. It is to be
understood that this disclosure is not limited to particular methods, and experimental conditions
described, as such methods and conditions may apply.
Materials and methods
10
[062] Lithium nickel manganese cobalt oxide (NMC) (cathode), and graphite (anode), were
procured from commercial sources.
Example 1
A method for electrolyte filling for a lithium-ion battery cell
[063] The cell was prepared prior to filling of the electrolyte 5 in the lithium-ion battery cell by
testing the Hi-pot resistance of all cells at 250V for 10 seconds using the battery short circuit
tester on the winding machine. It was confirmed that all cells passed the Hi-pot test
(>100Mohm). The cells that passed the tests were sealed with a temporary plug. Then, each
cell was weighed to ensure that it weighs between 310 to 320 g after removing the temporary
10 plug. The weighed cell was then placed into a sample holder for electrolyte filling.
[064] The machine for filling the electrolyte was set up by verifying the degassing time, high
pressure time, low vacuum time, and high vacuum time settings on the human-machine
interface according to Table 1. It was ensured that the number of cycles displayed on the screen
was set to 2. Then the number of inject cycles were entered as 15. The machine was then shifted
15 to auto mode to initiate the filling operation. The automated filling process was initiated by
pressing the pedal switch which will begin a sequence of operations.
[065] A cylindrical lithium-ion battery cell, C1 comprised of lithium nickel manganese cobalt
oxide (NMC; cathode) and graphite (anode) prepared as explained here was subjected to
electrolyte filling. Initially, a vacuum pressure of -85 kPa was applied to the lithium-ion battery
20 cell for 20 seconds. Then, the lithium-ion battery cell was degassed at a pressure of 0 kPa for
20 seconds, followed by applying high pressure of 20 kPa twice to fill 37.7g (±) 0.5g electrolyte
into the battery cell. Then a low vacuum was applied at -85 kPa, twice to create an internal
vacuum, which was followed by optionally applying high vacuum at -85 kPa for 40 seconds.
Finally, a pressure of 20 kPa was applied to complete the single filling of electrolyte into the
25 cell in 15 injection cycles in 4 minutes. Once the filling was completed, the final weight of the
cell was weighed and the cell was moved for closing pin welding.15 cells were filled with
electrolyte with no spillage, by the process as provided herein, in one hour.
[066] Similarly, a cylindrical lithium-ion battery cell, C2 was prepared by the process as
disclosed herein, wherein the process parameters are provided in Table 1.
30 [067] For comparative purposes, lithium-ion battery cells CP1 and CP2 underwent the
conventional multi-shot filling process, and two-shot filling method, respectively (Table 1),
wherein the cell was allowed to soak for a time period 15 to 20 minutes after electrolyte filling.
11
Table 1
Process C1 C2 CP1 CP2
Vacuum pressure
(kPa)
-85 -80 -80 -80
Vacuum time
(seconds)
20 20 20 20
Degassing pressure
(kPa)
0 3 3 3
Degassing time
(seconds)
20 35 20 20
High pressure (kPa) 20 35 20 20
High pressure time
(seconds)
40 50 20 20
Low vacuum pressure
(kPa)
-85 -80 -80 -80
Low vacuum time
(seconds)
40 50 20 20
High vacuum pressure
(kPa)
-85 -80 -80 -80
High vacuum time
(seconds)
40 50 20 20
Pressure (kPa) 20 28 23 23
Injection cycles
(Nos)
15 16 17 15
Filling time per cell
(minutes)
4 8.2 20 15
No. of cells per hour
(Nos)
15 7 3 4
5
12
Example 2
Evaluation of the lithium-ion battery cell
(a) CT Scan
[068] The survey meter was switched ON before starting the CT inspection. The TLD badge
was worn, and the vacuum gauge signal was confirmed to 5 be below 400. The drive control was
set to auto mode, and the X-Ray key was turned ON. The door was opened and then closed to
activate the warning alarm and lamp. The METROTOM OS software was launched and the XRay
Tube, Detector, and Positioning System was enabled by selecting "Initialize
METROTOM," which triggered a 30-minute warm-up. After warm-up, a 2 mm Cu filter was
10 placed at the focal spot, and the voltage was set to 100 kV and current to 100 μA, then the XRay
was switched ON and settings was increased to 150 kV and 200 μA, verifying that the
leakage dose was below 1 μSv/hr. The sample was prepared as per dimension limits (max 615
mm Dia/800 mm Height and 50 kg) and was placed it in a plastic container inclined at 15°–
20°, supported with foam, and mounted securely on the rotary table. The door was closed, and
15 the X-Ray was energized. The object was centred using the positioning menu, magnification
was adjusted, and a New Vast CT scan was started. The image quality was optimized with
voltage/current tweaks and filters. After finalizing positioning, scan parameters was input, and
the air region was defined, and the scanning was begun by selecting the Measure icon. Postprocess
the data in GOM Volume Inspect Pro by importing the scan file, polygonising and
20 aligning the model, adjusting 3D and 2D histograms, then capturing and exporting enhanced
images for analysis.
[069] The lithium-ion cell battery cell as prepared by the process as provided in Example 1
was evaluated by using CT scan method. From the Figure 1, it was observed that, the CT scan
results of the C1 (single-shot), CP1 (multi-shot), and CP2 (two-shot) were the same. Hence, it
25 was clear that the single shot filling process as provided in the Example 1 has not caused any
damage to the electrodes and separator. Further, it was confirmed that all the three cells
exhibited uniform electrolyte distribution. Thus, the efficiency and effectiveness of the
single-shot filling method as provided in Example 1, in terms of time savings and
production rate increase, while maintaining the quality of electrolyte distribution was
30 substantiated.
[070] It was confirmed that the electrolyte had thoroughly penetrated all layers of the
electrodes and separators. Therefore, the soaking step while filling can be safely omitted
without compromising electrolyte distribution or overall cell performance.
13
[071] Post-filling of the electrolyte into the cell, the cells were subjected to 24 hours of hightemperature
(HT) aging, which provided sufficient time for complete electrolyte wetting
throughout the jelly roll. It was observed that, after 8 hours, the electrolyte was fully absorbed
by the jelly roll.
ADVANTAGES 5 OF THE PRESENT DISCLOSURE
[072] The present disclosure provides a method for filling electrolyte for lithium-ion battery
cells. The method streamlines and enhances manufacturing efficiency by reducing the overall
filling time per cell, potentially doubling or tripling production rates, which increases the output
without additional equipment or floor space. Further, the method ensures uniform electrolyte
10 distribution comparable to more time-consuming methods, maintaining high quality standards.
The precise control inherent in the single-shot method as disclosed herein also minimizes
electrolyte waste by reducing overfilling and spillage, contributing to cost savings. Simplifying
the process into a single cycle reduces complexity and the likelihood of errors, making it more
scalable for high-volume production environments. Additionally, this method can be adapted
15 to various battery cell types and electrode materials, ensuring versatility. The standardized
process enhances consistency across batches, leading to improved quality, while shorter
exposure times help protect sensitive components from ambient conditions, potentially
boosting long-term performance and reliability. Hence, the method as disclosed herein provides
an efficient, cost-effective, and reliable battery manufacturing process with the potential for
20 higher quality and scalability.
14
I/We Claim:
1. A method for electrolyte filling for a lithium-ion battery cell, the method comprising:
i) degassing the battery cell at a pressure in a range of 0 kPa to 5 kPa;
ii) applying a high pressure at a range of 20 kPa to 50 kPa to fill the electrolyte
5 into the battery cell;
iii) applying a low vacuum step at a range of -40 kPa to -90 kPa to create an internal
vacuum in the battery-cell;
iv) optionally, applying high vacuum at a pressure in a range of -70 kPa to -90 kPa;
and
10 v) applying pressure in a range of 15 kPa to 30 kPa for complete electrolyte filling
into the cell.
2. The method as claimed in claim 1, wherein the method comprises applying a vacuum
pressure to the battery cell in a range of -70 kPa to -90 kPa, prior to the step (i).
3. The method as claimed in claim 1, wherein the steps (ii) and (iii) are repeated for 2-3
15 times.
4. The method as claimed in claim 1, wherein the steps (i) to (iv) are maintained for a time
period in a range of 20 seconds to 60 seconds.
5. The method as claimed in claim 1, wherein the method comprises filling the electrolyte
in a single filling cycle.
20 6. The method as claimed in claim 1, further comprising injecting electrolyte into the
lithium-ion battery cell in 15 to 16 injection cycles during the single filling cycle.
7. The method as claimed in claim 1, wherein the cell contains 35 to 45 grams of
electrolyte.
8. The method as claimed in claim 1, wherein the method results in electrolyte filling of
25 10 to 20 cells per hour.
9. A lithium-ion battery cell filled with electrolyte using the method as claimed in any one
of claims 1 to 7.
10. The lithium-ion battery cell as claimed in claim 9, wherein the cell is a cylindrical cell.
11. The lithium-ion battery cell as claimed in claim 9, wherein the cell contains 35 to 45
30 grams of electrolyte.
15
12. The lithium-ion battery cell as claimed in claim 9, wherein the cell comprises cathode
selected from layered metal oxides, spinel metal oxides or olivine phosphates; and
anode selected from graphite, silicon, silicon-carbon composites, or lithium titanate
oxide (LTO).
13. The lithium-ion battery cell as claimed 5 in claim 9, wherein the cell exhibits no
electrolyte spillage after the single filling cycle.
16
ABSTRACT
A METHOD FOR ELECTROLYTE FILLING AND LITHIUM-ION BATTERY
CELL THEREOF
The present disclosure provides a method for electrolyte filling for a lithium-ion battery
cell, the method comprising: (i) degassing the battery c 5 ell at a pressure in a range of 0 kPa
to 5 kPa; (ii) applying a high pressure at a range of 20 kPa to 50 kPa to fill the electrolyte
into the battery cell; (iii) applying a low vacuum step at a range of -40 kPa to -90 kPa to
create an internal vacuum in the battery-cell; (iv) optionally, applying high vacuum at a
pressure in a range of -70 kPa to -90 kPa and (v) applying pressure in a range of 15 kPa to
10 30 kPa for complete electrolyte filling into the cell. The present disclosure further provides
a lithium-ion battery cell filled with electrolyte using the method as disclosed herein.
17 , Claims:I/We Claim:
1. A method for electrolyte filling for a lithium-ion battery cell, the method comprising:
i) degassing the battery cell at a pressure in a range of 0 kPa to 5 kPa;
ii) applying a high pressure at a range of 20 kPa to 50 kPa to fill the electrolyte
5 into the battery cell;
iii) applying a low vacuum step at a range of -40 kPa to -90 kPa to create an internal
vacuum in the battery-cell;
iv) optionally, applying high vacuum at a pressure in a range of -70 kPa to -90 kPa;
and
10 v) applying pressure in a range of 15 kPa to 30 kPa for complete electrolyte filling
into the cell.
2. The method as claimed in claim 1, wherein the method comprises applying a vacuum
pressure to the battery cell in a range of -70 kPa to -90 kPa, prior to the step (i).
3. The method as claimed in claim 1, wherein the steps (ii) and (iii) are repeated for 2-3
15 times.
4. The method as claimed in claim 1, wherein the steps (i) to (iv) are maintained for a time
period in a range of 20 seconds to 60 seconds.
5. The method as claimed in claim 1, wherein the method comprises filling the electrolyte
in a single filling cycle.
20 6. The method as claimed in claim 1, further comprising injecting electrolyte into the
lithium-ion battery cell in 15 to 16 injection cycles during the single filling cycle.
7. The method as claimed in claim 1, wherein the cell contains 35 to 45 grams of
electrolyte.
8. The method as claimed in claim 1, wherein the method results in electrolyte filling of
25 10 to 20 cells per hour.
9. A lithium-ion battery cell filled with electrolyte using the method as claimed in any one
of claims 1 to 7.
10. The lithium-ion battery cell as claimed in claim 9, wherein the cell is a cylindrical cell.
11. The lithium-ion battery cell as claimed in claim 9, wherein the cell contains 35 to 45
30 grams of electrolyte.
15
12. The lithium-ion battery cell as claimed in claim 9, wherein the cell comprises cathode
selected from layered metal oxides, spinel metal oxides or olivine phosphates; and
anode selected from graphite, silicon, silicon-carbon composites, or lithium titanate
oxide (LTO).
13. The lithium-ion battery cell as