Performance and limitations of Si anodes in 18650 cells for military applications 

Lasantha Korala – Battery Scientist American Lithium Energy

0:00:02   scientist, that American lithium energy. Today I'm
0:00:09   going to show you some off the performance data off 18, 6 50 cells based on Silicon Graphite
0:00:15   Composite An office. These cells are primary designed for military applications. I will also discuss
0:00:22   some off the key challenges off the system on how we're going to address those issues. Let me start
0:00:30   the presentation briefly introducing our company. American Lithium Energy Cooperation was founded in
0:00:36   2006, and our main goal leaves designed, developed and commercialized next generation lithium ion
0:00:44   cells for demanding military and commercial applications. Over the years, we have developed a
0:00:50   several proprietary process development methods to manufacture high energy and high power lithium
0:00:56   ion cells. We have also developed a proprietary safety technology called Safeco, and this can be
0:01:02   applied to both military and commercial batteries. Up to now, we have over 23 should patents with
0:01:10   worldwide coverage and another 10 pending applications. Our 24,000 square feet state off the art
0:01:18   facility is located in San Diego County. On this facility is is 9 100 d certified, so this allows us
0:01:26   to reliably manufacturing in mind sells for both heros, faith and different applications. We have 18,
0:01:34   6 50 prismatic and pouch format prototype cell production lines with two high volume advanced
0:01:40   coating systems. These court systems are capable of producing several million electrodes per year.
0:01:47   Another nice feature off our facilities we have in house safety testing capabilities. So this allows
0:01:54   us to rapidly evaluate the search for humans off ourselves. So in this slide, I would like to point
0:02:02   out some off the key requirements off letting mind cells developed for military applications. So, as
0:02:09   in the case of commercial applications says should have a high energy, high power, unreasonably long
0:02:15   cycle life, and also they should be able to produce that reasonably lower cost. However, in contrast,
0:02:23   toe commercial applications, military applications require enhanced safety for extreme abuse. For
0:02:29   example, Bull administration and also says, should be able to operate across a much wider
0:02:37   temperature range, for example, from minus 40 degrees to 60 degrees. Another important requirement
0:02:43   is domestic manufacturing capability. This is critical to maintain supply chain in times off
0:02:50   conflict. So in next flu side, I will show how a little itty man cells meet these requirements
0:02:59   early has been developing a several lithium and sell products based on silicon graphite composite in
0:03:04   order for military applications. Our prismatic and poach formats Elsa targeted for conform aware of
0:03:11   our batteries and these cells have over 350 watt hours per kilogram specific energy and they can be
0:03:17   operated across a white temperature range. We're also developing two types of 18 6 50 cells for B B
0:03:25   2, 50 90 and large format batteries. Our high energy 18 6 50 cells have over 351 topic low Graham
0:03:33   specific energy and over four power capacity. These cells also can be operated across a white
0:03:40   temperature range. Our high power cells have over 200 what our per kilograms specific energy and
0:03:47   over three point to empower capacity. The unique feature off these cells is they have excellent park
0:03:54   ever will get low temperature. For example, they can deliver 25 watt discharge at minus 40 degrees.
0:04:03   For this presentation, I am going to mainly focus on high energy 18 6 50 with your mind cells. This
0:04:10   graph shows the evolution off commercial 18 6 50 cells since its first introduction in 1990 Blue
0:04:18   Ghoshal cell capacity or in school social specific energy. As you can see in the graph, cell
0:04:24   capacity and specific energy gradually increased over time until 2012. Since the introduction, off
0:04:32   3.5 and parcel in 2020. There is virtually no increase in cell capacity. Cell specific energy has
0:04:40   slightly increased since 2012, mainly due toa introduction off small percentage off silicon to the
0:04:47   Cafe Donald. However, Ellie was able to break this trend by significantly increasing silicon content
0:04:54   in composite and art. In 2020 we introduce our first generation for empower 18 6 50 cells with over
0:05:02   300 watt hour program specific energy.
0:05:07   This is our short terms and development roadmap for high energy 18 6 50 cells. As I mentioned before,
0:05:15   current generation high energy rating 6 50 cells have foreign power capacity on 220 water per
0:05:22   kilogram specific energy by the end of next year. Our goal is to increase the capacity of 4.4 um
0:05:30   power with 350 watt hours per kilogram specific energy. We're planning to further increase the
0:05:37   capacity up to 4.8 empower with 365 watt hours per kilogram specific energy by the end of 2022. So
0:05:47   in next few slides, I would like to present some key performance data for current generation foreign
0:05:53   power cells.
0:05:56   This slide shows rate and low temperature performances off foreign power Selves. The tough club
0:06:02   shows this search capacity attention at different cities at room temperature, as you can see in the
0:06:09   graph for empower cells show excellent rate performance, and they can deliver over 92% off cell
0:06:15   capacity at once they discharge rate. The bottom graph shows discharge capacity attention at
0:06:22   different temperatures here. Discharge ratings point to see. As you can see in the graph, these
0:06:28   cells can be operated across a wide temperature range one off the key attributes for military
0:06:33   application. For example, at minus 40 degrees Celsius, cells can deliver over 50% off cell capacity
0:06:41   at 500.208 In fact, our next generations self show even better low temperature performance. They can
0:06:50   deliver close to 70% off the capacity at minus 40 degrees Celsius and point to see discharge rate.
0:06:59   Another important performance metric for military applications is high temperature storage. This
0:07:05   graph shows capacity retention and capacity recovery after 60 degrees Celsius. Storage for one week
0:07:13   at 100%. State offs charge the sales showed close to 95% capacity, attention after storage and
0:07:22   negligible, irreversible capacity loss as indicated by over 99% capacity recovery.
0:07:30   We have been continually increasing cycle life performance off our high energy. 18 6 50 cells
0:07:37   describe shows capacity retention on discharge capacity 100% of top discharge during cell cycling.
0:07:45   In fact, the cell capacity is a little over 4.1 M Power charge rate is C 03 on discharge rate is 05
0:07:53   These cells can be cycled over 200 times with 80% capacity retention.
0:08:01   Next, I would like to discuss the safety performance off our 86 50 years left. Graph shows
0:08:07   temperature profile of a four and power cell during 130 degrees Celsius. Hotbox test at 100%. State
0:08:14   off. Charge the silken past the hotbox test without catching fire or explosion on right graph shows
0:08:21   cell temperature profile during overcharge test here, the cell waas charged upto eight world and
0:08:27   again still can pass all charge test without catching fire or explosion. However, as I mentioned
0:08:34   before for military applications, cells should be able to withstand extreme abuse, such as bull
0:08:40   administration. This is a tough challenge for any cell, but a particularly a hard one for silicon
0:08:47   with high energy 18 6 50 format cells.
0:08:53   In order to compare these safety issues related to lithium ion cells, we have developed a
0:08:59   proprietary, better safety technology called Safeco. Simply. Safeco is a layer that can be
0:09:06   conveniently corded or another or cathode current collector. This courting can be done by typical
0:09:12   rolled role processing without to use off any advance depression meters. The schematic shows the
0:09:19   working mechanism off the created safe Kolia. So in the event off electrical mechanical low thermal
0:09:25   abuse safe Kolia decomposes and creates a gap between the electrode and current collector. This gap
0:09:33   effectively increases the cell. Internal resistance by several ordered soft magnitude and reduces
0:09:39   the internal search circuit can flow local and flow means minimal heat generation, and this prevents
0:09:46   occurrence off thermal runaway. In 2016, a least one off a company called um you knocks to focus
0:09:53   wholly on consumer applications. Recently, they have entered into a license agreement for Safeco,
0:10:00   which Stanley Black and Decker
0:10:04   to demonstrate the effectiveness off safe for in the event off severe Internet short, we help
0:10:10   performed both nail penetration tests on blood penetration tests on partial former. The graph on the
0:10:17   left side shows the cell voltage and temperature profile during the penetration test Off fire
0:10:23   Barcella. As you can see in the inside figure the cell can pass the noticed without catching fire or
0:10:29   exposure. I would like to spend some time here to explain this phenomenon. As you can see in the
0:10:36   voltage profile, there's a sudden drop off cell voltage at the nation Elka. However, the cell
0:10:43   voltage quickly rebounded back on, then decrease gradually over time. Also, as you can see in
0:10:50   temperature profile, cell temperature increase after nail contact and then started to decrease
0:10:56   gradually. After reaching the maximum value on the right, you can see an image of a separate layer
0:11:04   where you can see the separate and melting around their penetration area. This suggests that the
0:11:10   local temperature has risen at least up to 130 big associates around the nail penetration area, so
0:11:19   these observations are in line with working mechanism off to safety. As I described in the previous
0:11:25   life. The initial legs contract droves high current on increases the local temperature around the
0:11:31   initial around. The nail significant. This causes separator melting and sudden drop of 40. This
0:11:40   local temperature increase triggers Safeco activation around the nail penetration area. On this
0:11:45   converts low temperature internal short Work, High Resistance International, and this leads to a
0:11:53   quick rebound off the cell voltage on, then gradual voltage dick. Also, the slow discharge generates
0:12:00   minimal heat on cell temperature reaches to a slightly higher value than room temperature without
0:12:07   leading to a thermal runaway. Currently, we are in the process of applying safe for technology. Tow
0:12:14   our high energy 18 63 form ourselves
0:12:20   in some way. A Lee Hyeon 80 18 6 50 cells show Excellent features that can be employed for a wide
0:12:28   range of military devices are waiting 6 50 cells higher. 90. An excellent power capability. These
0:12:36   cells can be manufactured that reasonably lower cost because off the employment off standard lady in
0:12:42   my cell manufacturing it as a domestic cell manufacturer, Ale is uniquely capable of providing
0:12:51   reliable sells off life for military application. Our 18 6 50 sales have also demonstrated excellent
0:12:58   high temperatures, storage performance can be operated across a wide temperature ring. With the
0:13:05   employment off, our provider is safe for technology. We are hoping to significantly and have self
0:13:12   safety for demanding military application. Over the years, we have built up a strong relationship on
0:13:20   successful partnership with many leading battery manufacturers and defense contractors. So this
0:13:26   gives us a strong access toe military bedroom market. At this point, we are in the process of
0:13:33   expanding our domestic cell manufacturing capability. Did that I would like to refer my presentation
0:13:40   on thank you very much for your attention.