Prelithiated electrode improvement

Abstract

A system for processing a prelithiated electrode is provided. The system includes: a process chamber comprising: a chamber body disposed around an interior volume; a first support shaft in the interior volume, the first support shaft configured to support a first roll of prelithiated electrode; and a first temperature sensor configured to measure a temperature of the first roll of prelithiated electrode positioned on the first support shaft; and a cooling source fluidly coupled with the interior volume, the cooling source configured to cool the interior volume.

Description

PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCTPRELITHIATED ELECTRODE IMPROVEMENTBACKGROUND

[0001] Embodiments of the present disclosure generally relate to equipment and methods for improving the product quality of prelithiated electrodes.Description of the Related Art

[0002] Different materials can be used for the anode of lithium-ion batteries, such as one or more of copper, silicon, and graphite. Prelithiation is a technique that adds lithium to an electrode (e.g., the anode) of a lithium-ion battery to prevent loss of lithium ions that act as charge carriers during use of the lithium-ion battery. Preventing this loss of lithium ions can improve the useful life of a lithium-ion battery by reducing performance loss that can occur with aging of the battery.

[0003] Lithium can be added to the anode using a variety of techniques, such as directly depositing the lithium on the anode or using roll-to-roll applications to press the lithium layer onto the anode.

[0004] Although prelithiation of substrates (e.g., flexible substrates) serving as the anode can improve the performance of lithium-ion batteries, it still remains difficult to obtain consistent product quality. Accordingly, there is a need for improved methods and equipment that can further improve the product quality of prelithiated electrodes.SUMMARY

[0005] In one embodiment, a system for processing a prelithiated electrode is provided. The system includes: a process chamber comprising: a chamber body disposed around an interior volume; a first support shaft in the interior volume, the first support shaft configured to support a first roll of prelithiated electrode; and a first temperature sensor configured to measure a temperature of the first roll of prelithiated electrode positioned on the first support shaft; and a cooling source fluidly coupled with the interior volume, the cooling source configured to cool the interior volume.

[0006] In another embodiment, a method of controlling an alloying process of a prelithiated electrode is provided. The method includes: positioning a roll of prelithiated electrode in an interior volume of a process chamber, wherein the prelithiated electrode is undergoing an alloying process between a lithium layer andPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT an electrode material of the prelithiated electrode when the roll of prelithiated electrode is positioned in the interior volume of the process chamber; providing an inert gas to the interior volume of the process chamber when the prelithiated electrode is positioned in the process chamber; and maintaining the interior volume at a vacuum pressure when the prelithiated electrode is positioned in the process chamber.

[0007] In another embodiment, a method of controlling an alloying process of a prelithiated electrode is provided. The method includes: positioning a roll of prelithiated electrode in an interior volume of a process chamber, wherein the prelithiated electrode is undergoing an alloying process between a lithium layer and an electrode material of the prelithiated electrode when the roll of prelithiated electrode is positioned in the interior volume of the process chamber; supplying an inert gas to the interior volume of the process chamber when the prelithiated electrode is positioned in the process chamber; measuring a temperature in the interior volume when the prelithiated electrode is positioned in the process chamber; and adjusting an amount of cooling provided to interior volume based on the temperature measurements.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0009] Figure 1 shows a side cross-sectional view of a processing system, according to one embodiment.

[0010] Figure 2 is a process flow diagram of a method of controlling the alloying process of one or more rolls of prelithiated electrodes in the process chamber using the processing system of Figure 1 , according to one embodiment.

[0011] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It isPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0012] Embodiments of the present disclosure generally relate to equipment and methods for improving the product quality of prelithiated electrodes.

[0013] After the lithium is added to the anode for a lithium-ion battery, the lithium interacts with the material of the anode (e.g., copper, silicon, or carbon of the graphite) resulting in an alloying process in which the lithium and material of the anode mix together. The alloying process can often take several hours. The alloying process is an exothermic reaction, which leads to temperature changes of the prelithiated electrode during the alloying process. It is believed the excess heat generated by the exothermic reactions of the alloying processes can lead to product quality issues for the prelithiated electrodes. The excess heat from the exothermic reactions can also potentially lead to safety issues as lithium is a highly combustible material that can ignite when exposed to oxygen or water. This disclosure addresses the problem of excess heat from the exothermic alloying reactions by positioning the prelithiated electrodes in a controlled environment during the alloying process.

[0014] Figure 1 shows a side cross-sectional view of a processing system 100, according to one embodiment. The processing system 100 includes a process chamber 101 , a gas supply system 130, a vacuum pump 140, a recirculation cooling unit 150, and a controller 185.

[0015] The process chamber 101 includes a chamber body 102 disposed around an interior volume 110. The chamber body 102 includes a top 103, a bottom 104, and one or more sidewalls 105 connecting the top 103 with the bottom 104. The process chamber 101 can include a door 106 configured to open to allow the transferring of rolls of prelithiated electrodes into and out of the interior volume 110 of the process chamber 101. In some embodiments, the door 106 forms all or a portion of one of the one or more sidewalls 105 of the process chamber 101 .

[0016] The process chamber 101 includes a first support shaft 11 1 and a second support shaft 112. Each support shaft 111 , 112 is configured to support a roll 50 of prelithiated electrode 51 during processing. A roll 50 of prelithiated electrode 51 isPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT shown positioned on the first support shaft 111. The roll 50 can include an inner tube 55. The prelithiated electrode 51 is wound around the inner tube 55. The inner tube 55 can be hollow and can be configured to slide onto the first support shaft 111. In some embodiments, the process chamber can include three or more support shafts with each support shaft configured to support a roll 50 of prelithiated electrode 51 .

[0017] The gas supply system 130 can include a plurality of gas sources 131-134 configured to supply different gases to the interior volume 110 of the process chamber 101. In one embodiment, the first gas source 131 is configured to supply clean dry air, the second gas source 132 is configured to supply an inert gas (e.g., argon), the third gas source 133 is configured to supply carbon dioxide, and the fourth gas source is configured to supply sulfur hexafluoride. The clean dry air can assist in creating a safe environment for an operator during loading and unloading of the rolls 50 of prelithiated electrodes 51. The argon can assist in creating an inert environment in the interior volume 110 or act as a carrier gas for the other gases, such as the carbon dioxide or sulfur hexafluoride.

[0018] The carbon dioxide can be used to passivate exposed lithium surfaces of the prelithiated electrode 51 by forming a passivation layer of lithium carbonate (Li2COs) over the exposed lithium surfaces. The sulfur hexafluoride can be used to passivate the exposed lithium surfaces by forming a passivation layer of lithium fluoride (Li F) or lithium sulfur hexafluoride (LixSFe). These passivation layers prevent negative reactions from occurring between lithium and components in the ambient environment, such as the reactions with nitrogen. As these passivation layers form, the available locations for the lithium to react with ambient environment are consumed, and thus after the formation of the passivation layer is completed, the negative reactions between the lithium and components (e.g., nitrogen) of the ambient environment are prevented or substantially reduced.

[0019] Other gases that can be used to form passivation layers on a lithium surface include carbon monoxide (CO), carbon tetrafluoride (CF4), ammonia (NH3) as well as other oxide, fluoride, and chloride gases. The thickness of the passivation layers formed on the lithium surfaces can be from about 1 nm to about 1000 nm, such as from about 10 nm to about 500 nm.PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT

[0020] The gas supply system 130 can further include a plurality of valves (not shown) for controlling the flow of each of the gases from the gas sources 131-134 to the interior volume 110 during different portions of the process.

[0021] The vacuum pump 140 can be fluidly coupled with the interior volume 110 of the process chamber 101 . The vacuum pump 140 can be used to exhaust gases from the interior volume 110 as well as maintain a vacuum pressure in the interior volume 110. For example, the vacuum pump 140 can be used to exhaust the clean dry air that includes nitrogen from the interior volume when a new roll 50 of prel ithiated electrode 51 is positioned in the interior volume 110. The vacuum pump 140 can then be used to remove passivation reaction byproducts from the interior volume 110. In some embodiments, which can be combined with other embodiments, the vacuum pump 140 is used to reduce the pressure in the interior volume to a pressure from about 0.001 millibar to about 0.1 millibar.

[0022] The recirculation cooling unit 150 can be used to maintain a temperature in the interior volume 110 below a specified temperature, such as a temperature in a range from about -5°C to about 25°C. The recirculation cooling unit 150 can be fluidly coupled with the interior volume 110 of the process chamber 101 . The recirculation cooling unit 150 can be configured to circulate gases from the interior volume 110, through the recirculation cooling unit 150, and then return the gases in a cooled state to the interior volume 110. The recirculation cooling unit 150 can include a blower for circulating the gases. The recirculation cooling unit 150 can include a heat exchanger for cooling the gases from the interior volume 110 before the gases are returned to the interior volume 110. The recirculation cooling unit 150 is one example of a cooling source that can be used to maintain the temperatures in the process chamber 101 below specified temperatures. The recirculation cooling unit 150 can be used to maintain a temperature of the roll 50 of prelithiated electrode 51 below a specified temperature, such as a temperature in a range from about 0°C to about 35°C

[0023] The recirculation cooling unit 150 can keep the interior volume 110 of the process chamber 101 below a specified temperature while also reducing the amount of fresh gas that is needed from the gas sources 131-134, which reduces operating costs.PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT

[0024] In some embodiments, which can be combined with other embodiments, the processing system 100 can increase the flow of inert gas to the interior volume 110 to assist in maintaining a temperature of the interior volume 110 or a temperature of the roll 50 of prelithiated electrode 51 below a specified temperature.

[0025] The process chamber 101 can further include a plurality of sensors 161- 166 to assist in controlling the process chamber 101 during the alloying process of the prelithiated electrode 51 in the interior volume 110. The first support shaft 111 can include a temperature sensor 161 (e.g., a thermocouple) to measure the temperature of the roll 50 of prelithiated electrode 51 . In some examples, the temperature sensor 161 can be configured to contact the inner tube 55 of the roll 50. The second support shaft 1 12 can include a corresponding temperature sensor 162 for measuring the temperature of a roll 50 of prelithiated electrode 51 positioned on the second support shaft 112. The process chamber 101 can further include a temperature sensor 163 for measuring the temperature of the interior volume 110 of the process chamber 101. Measurements from the temperature sensors 161-163 can be used by the controller 185 to control the amount of cooling provided by the recirculation cooling unit 150.

[0026] The process chamber 101 can further include a pressure sensor 164 for measuring the pressure of the interior volume 110 of the process chamber 101. Measurements from the pressure sensor 164 can be used by the controller 185 to control the vacuum pump 140.

[0027] In some embodiments, which may be combined with other embodiments, the process chamber 101 can further include an ultraviolet / infrared sensor 165 to detect unsafe conditions, such as ignition of the prelithiated electrode 51 . Additionally, the process chamber 101 can further include one or more sensors 166 configured to determine the composition of the gases in the interior volume 110. For example, the one or more sensors 166 can include one or more of a residual gas analyzer, an oxygen sensor, and a carbon dioxide sensor.

[0028] The processing system 100 also includes the controller 185 for controlling processes performed by the processing system 100. The controller 185 can be any type of controller used in an industrial setting, such as a programmable logic controller (PLC). The controller 185 includes a processor 187, a memory 186, and input / outputPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT(I / O) circuits 188. The controller 185 can further include one or more of the following components (not shown), such as one or more power supplies, clocks, communication components (e.g., network interface card), and user interfaces typically found in controllers for semiconductor equipment.

[0029] The memory 186 can include non-transitory memory. The non-transitory memory can be used to store the programs and settings described below. The memory 186 can include one or more readily available types of memory, such as read only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM).

[0030] The processor 187 is configured to execute various programs stored in the memory 186, such as programs for controlling the conditions in the interior volume 110 when the prelithiated electrodes 51 are undergoing the alloying process in the process chamber 101. During execution of these programs, the controller 185 can communicate to I / O devices through the I / O circuits 188. For example, during execution of these programs and communication through the I / O circuits 188, the controller 185 can control outputs, such as changing the position of valves (not shown) to send different gases to the interior volume 1 10 of the process chamber 101 , and the controller 185 can monitor the measurements from the sensors 161-166. The memory 186 can further include various operational settings used to control the processing system 100. For example, the settings can include pressure and temperature settings at which the controller 185 can maintain the interior volume 110 when the prelithiated electrodes 51 are undergoing the alloying process in the interior volume 110. The controller 185 can use the pressure settings along with measurements from the pressure sensor 164 to adjust the speed of the vacuum pump. The controller 185 can use the temperature settings along with measurements from the temperatures sensors 161 -163 to adjust the amount of cooling provided by the recirculation cooling unit 150.

[0031] Figure 2 is a process flow diagram of a method 2000 of controlling the alloying process of one or more rolls 50 of prelithiated electrodes 51 in the process chamber 101 using the processing system 100 of Figure 1 , according to onePCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT embodiment. Many portions of the method 2000 can be performed by the controller 185. With reference to Figures 1 and 2, the method 2000 is described.

[0032] The method begins at block 2002. At block 2002, the interior volume 110 of the process chamber 101 is filled with clean dry air from the first gas source 131 .

[0033] At block 2004, the door 106 of the process chamber 101 is opened and one or more rolls 50 of prelithiated electrodes 51 are loaded into the interior volume 110 of the process chamber 101. Each roll 50 of the prelithiated electrode 51 can be positioned on one of the corresponding support shafts 1 11 , 112. Each roll 50 of prelithiated electrode 51 is currently undergoing an alloying process between the lithium layer and the electrode material (e.g., copper, graphite, or silicon) of the prelithiated electrode when the roll 50 of prelithiated electrode 51 is positioned in the process chamber.

[0034] At block 2006, the door 106 is closed and the inert gas (e.g., argon) from the second gas source 132 is supplied to the interior volume 110 of the process chamber 101 . When the door 106 is closed, the vacuum pump 140 can begin lowering the pressure in the interior volume 110 to a vacuum pressure (e.g., from about 0.001 millibar to about 0.1 millibar. In some embodiments, one or more pump and purge cycles can be used to assist in removing all of the gas (e.g., clean dry air) present in the interior volume before closure of the door 106.

[0035] In some embodiments, which can be combined with other embodiments, one or more of the passivating gases from the third gas source 133 (e.g., source of carbon dioxide) and the fourth gas source 134 (e.g., source of sulfur hexafluoride) are also supplied to the interior volume 110 with the inert gas from the second gas source 132. Alternatively, the passivating gases may be omitted, for example if the lithium surfaces of the prelithiated electrode are already passivated.

[0036] The inert gas can assist in creating an inert environment in the interior volume 110 or act as a carrier gas for the passivating gases when one or more of the passivating gases are used. Carbon dioxide can passivate the lithium surface by forming a passivation layer of lithium carbonate (U2CO3). Sulfur hexafluoride can passivate the lithium surface by forming a passivation layer of lithium fluoride (LiF) or lithium sulfur hexafluoride (LixSFe). In some examples, the one or more passivatingPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT gases may be provided for only a portion of block 2006, for example a time period that allows the lithium surface to be fully passivated. After the lithium surface of the prelithiated electrode is fully passivated, the controller 185 can then continue to supply the inert gas without the one or more passivating gases, so that the alloying process of the prelithiated electrode 51 can continue in an inert environment.

[0037] During block 2006, the controller 185 can control various conditions in the interior volume 110 of the process chamber 101. For example, the controller 185 can control the pressure in the interior volume 110 by monitoring the measurements from pressure sensor 164 and adjusting the speed of the vacuum pump 140 and / or adjusting the flow rates of the one or more gases provided to the interior volume 110 from the gas supply system 130. Similarly, the controller 185 can control the temperature of the interior volume 110 or temperature of the rolls 50 of prelithiated electrodes 51 by monitoring the measurements from the corresponding temperature sensors 161-163 and adjusting the amount of cooling provided by the recirculation cooling unit 150.

[0038] At block 2008, the controller 185 determines whether the alloying process is sufficiently complete and whether to continue operating at block 2006 or to proceed to block 2010. The controller 185 can be configured to continue the operation at block 2006 until the alloying process of the prelithiated electrode is complete or substantially complete (e.g., greater than 90% complete). The controller 185 can determine when to end block 2006 based on expiration of a timer (e.g., a six hour timer) or by monitoring the measurements from one or more of the sensors. For example, in one embodiment, a temperature of one of the rolls 50 of prelithiated electrodes 51 as measured by one of the temperature sensors 161 , 162 can be used to determine when the alloying process is complete or substantially complete. In another embodiment, measurements from the one or more composition sensors 166 can be used to determine when the alloying process is complete or substantially complete. In some embodiments, the controller 185 can also confirm the passivating process is complete before determining to end the operation at block 2006.

[0039] At 2010, the interior volume 110 of the process chamber 101 is filled with clean dry air from the first gas source 131 .PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT

[0040] At block 2012, the door 106 of the process chamber 101 is opened and one or more rolls 50 of prelithiated electrodes 51 are removed from the interior volume 110 of the process chamber 101 .

[0041] While the foregoing is directed to examples of the present disclosure, other and further examples of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCTWhat is claimed is:1 . A system for processing a prelithiated electrode comprising: a process chamber comprising: a chamber body disposed around an interior volume; a first support shaft in the interior volume, the first support shaft configured to support a first roll of prelithiated electrode; and a first temperature sensor configured to measure a temperature of the first roll of prelithiated electrode positioned on the first support shaft; and a cooling source fluidly coupled with the interior volume, the cooling source configured to cool the interior volume.

2. The system of claim 1 , wherein the cooling source is a recirculation cooling unit that is configured to: receive gases from the interior volume of the process chamber; cool the gases, and return the gases in a cooled state to the interior volume of the process chamber.

3. The system of claim 1 , further comprising a second support shaft, the second support shaft configured to support a second roll of prelithiated electrode.

4. The system of claim 3, further comprising a second temperature sensor coupled to the second support shaft, the second temperature sensor configured to measure a temperature of the second roll of prelithiated electrode positioned on the second support shaft.

5. The system of claim 1 , further comprising a gas source coupled with the interior volume of the process chamber, wherein the gas source contains a passivating gas configured to passivate a lithium surface of the first roll of prelithiated electrode.

6. The system of claim 5, wherein the passivating gas is carbon dioxide.

7. The system of claim 5, wherein the passivating gas is sulfur hexafluoride.

8. A method of controlling an alloying process of a prelithiated electrode, the method comprising: positioning a roll of prelithiated electrode in an interior volume of a process chamber, wherein the prelithiated electrode is undergoing an alloying process between a lithium layer and an electrode material of the prelithiated electrode whenPCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT the roll of prelithiated electrode is positioned in the interior volume of the process chamber; providing an inert gas to the interior volume of the process chamber when the prelithiated electrode is positioned in the process chamber; and maintaining the interior volume at a vacuum pressure when the prelithiated electrode is positioned in the process chamber.

9. The method of claim 8, further comprising: measuring a temperature in the interior volume when the prelithiated electrode is positioned in the process chamber; and adjusting an amount of cooling provided to interior volume based on the temperature measurements.

10. The method of claim 8, wherein positioning the roll of prelithiated in the process chamber comprises positioning the roll on a first support shaft.11 . The method of claim 10, further comprising measuring a temperature of the roll of prelithiated electrode using a temperature sensor coupled to the first support shaft.

12. The method of claim 11 , further comprising adjusting an amount of cooling provided to interior volume based on the temperature measurements.

13. The method of claim 8, further comprising supplying a passivating gas to the interior volume of the process chamber when the roll of prelithiated electrode is positioned in the interior volume of the process chamber, wherein the passivating gas is configured to react with lithium in a lithium layer of the prelithiated electrode to form a passivating layer over the lithium layer.

14. The method of claim 13, wherein the passivating gas is carbon dioxide.

15. The method of claim 13, wherein the passivating gas is sulfur hexafluoride.

16. A method of controlling an alloying process of a prelithiated electrode, the method comprising: positioning a roll of prelithiated electrode in an interior volume of a process chamber, wherein the prelithiated electrode is undergoing an alloying process between a lithium layer and an electrode material of the prelithiated electrode when the roll of prelithiated electrode is positioned in the interior volume of the process chamber; supplying an inert gas to the interior volume of the process chamber when the prelithiated electrode is positioned in the process chamber;PCT / US25 / 39736 29 July 2025 (29.07.2025)Attorney Docket No.: E165-0159PCT measuring a temperature in the interior volume when the prelithiated electrode is positioned in the process chamber; and adjusting an amount of cooling provided to interior volume based on the temperature measurements.

17. The method of claim 16, wherein the cooling is provided by a recirculation cooling unit that: receives gases from the interior volume of the process chamber; cools the gases, and returns the gases in a cooled state to the interior volume of the process chamber.

18. The method of claim 16, further comprising supplying a passivating gas to the interior volume of the process chamber when the roll of prelithiated electrode is positioned in the interior volume of the process chamber, wherein the passivating gas is configured to react with lithium in a lithium layer of the prelithiated electrode to form a passivating layer over the lithium layer.

19. The method of claim 18, wherein the passivating gas is carbon dioxide.

20. The method of claim 18, wherein the passivating gas is sulfur hexafluoride.

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