# US 10,770,760 B2 · Replenished negative electrodes for secondary batteries > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,760 B2 - Document ID: US10770760B2 - Status: Granted - Kind: B2 - Application number: 15/572,191 - Filed: 2016-05-06 - Published: 2018-05-31 - Granted: 2020-09-08 - Earliest claimed: 2015-05-08 - Assignees: Enovix Corporation - Applicants: Enovix Corporation - Inventors: Christopher G. Castledine; David T. Fouchard; Jonathan C. Doan; Christopher J. Spindt; Robert M. Spotniz; James D. Wilcox; Ashok Lahiri; Murali Ramasubramanian - Web page: https://patentgrep.com/patent/US10770760B2 ## CPC - H01M 10/448: {End of discharge regulating measures} - H01M 4/386: {Silicon or alloys based on silicon} - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/446: {Initial charging measures} - H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A method is provided for activating a secondary battery having a negative electrode, a positive electrode, and a microporous separator between the negative and positive electrodes permeated with carrier-ion containing electrolyte, the negative electrode having anodically active silicon or an alloy thereof. The method includes transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery, and transferring carrier ions from an auxiliary electrode to the positive electrode, to provide the secondary battery with a positive electrode end of discharge voltage Vpos,eod and a negative electrode end of discharge voltage Vneg,eod when the cell is at a predefined Vcell,eod value, the value of Vpos,eod corresponding to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li). ## Claims ### Claim 1 A method for activating a secondary battery, the secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative and positive electrodes permeated with a carrier ion-containing electrolyte in ionic contact with the negative and positive electrodes, and a control unit programmed with a predefined cell end of discharge voltage Vcell,eod value, the negative electrode comprising anodically active silicon or an alloy thereof and having a coulombic capacity for the carrier ions, the positive electrode comprising a cathodically active material and having a coulombic capacity for the carrier ions, the negative electrode coulombic capacity exceeding the positive electrode coulombic capacity, the method comprising: (i) transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery wherein a solid electrolyte interphase is formed on a surface of the negative electrode during the transfer, and (ii) transferring carrier ions from an auxiliary electrode to the positive electrode, to provide the secondary battery with a positive electrode end of discharge voltage Vpos,eod and a negative electrode end of discharge voltage Vneg,eod when the cell is at the predefined Vcell,eod value, wherein the value of Vpos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li). ### Claim 2 (depends on 1) The method of claim 1, wherein step (ii) is performed after or simultaneously with step (i). ### Claim 3 (depends on 2) The method of claim 2, wherein in a case where step (ii) is performed after step (i), the process further comprises step (iii) of transferring, after step (ii), carrier ions from the positive electrode to the negative electrode to charge the secondary battery. ### Claim 4 (depends on 2) The method of claim 2, wherein step (ii) is performed simultaneously with step (i), and wherein step (ii) comprises transferring carrier ions from the auxiliary electrode to the positive electrode at a first rate, and step (i) comprises transferring carrier ions from the positive electrode to the negative electrode at a second rate, the second rate being higher that the first rate. ### Claim 5 (depends on 1) The method of claim 1 wherein the value of Vpos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at Vcell,eod. ### Claim 6 (depends on 1) The method of claim 1 wherein the value of Vpos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 99% of its coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at Vcell,eod. ### Claim 7 (depends on 1) The method of claim 1 wherein Vneg,eod is at least 0.4 V (vs Li) but less than 0.8 V (vs Li) when the cell is at Vcell,eod. ### Claim 8 (depends on 1) The method of claim 1 wherein Vneg,eod is at least 0.5 V (vs Li) but less than 0.7 V (vs Li) when the cell is at Vcell,eod. ### Claim 9 (depends on 1) The method of claim 1 wherein the carrier ions are lithium, sodium, potassium, magnesium or aluminum ions. ### Claim 10 (depends on 1) The method of claim 1 wherein the carrier ions are lithium ions. ### Claim 11 (depends on 1) The method of claim 1 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 1.2:1, respectively, when cycled against a counter-electrode. ### Claim 12 (depends on 1) The method of claim 1 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 1.5:1, respectively, when cycled against a counter-electrode. ### Claim 13 (depends on 1) The method of claim 1 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 2:1, respectively, when cycled against a counter-electrode. ### Claim 14 (depends on 1) The method of claim 1 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 5:1, respectively, when cycled against a counter-electrode. ### Claim 15 (depends on 1) The method of claim 1 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 1.2:1, respectively, when cycled against a counter-electrode. ### Claim 16 (depends on 1) The method of claim 1 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 1.5:1, respectively, when cycled against a counter-electrode. ### Claim 17 (depends on 1) The method of claim 1 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 2:1, respectively, when cycled against a counter-electrode. ### Claim 18 (depends on 1) The method of claim 1 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 5:1, respectively, when cycled against a counter-electrode. ### Claim 19 (depends on 1) The method of claim 1 wherein the negative electrode comprises a silicon-containing active material that contains a significant void volume fraction to accommodate volume expansion and contraction as carrier ions are incorporated into or leave the negative electrode during charging and discharging cycles. ### Claim 20 (depends on 19) The method of claim 19 wherein the void volume fraction of the anodically active material is at least 0.1. ### Claim 21 (depends on 19) The method of claim 19 wherein the void volume fraction of the anodically active material is not greater than 0.8. ### Claim 22 (depends on 19) The method of claim 19 wherein the void volume fraction of the anodically active material is about 0.15 to about 0.75. ### Claim 23 (depends on 19) The method of claim 19 wherein the void volume fraction of the anodically active material is about 0.25 to about 0.6. ### Claim 24 (depends on 19) The method of claim 19 wherein the anodically active material comprises macroporous, microporous or mesoporous material layers or a combination thereof. ### Claim 25 A secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative and positive electrodes permeated with a carrier ion-containing electrolyte in ionic contact with the negative and positive electrodes, an auxiliary electrode, and a control unit, wherein the positive electrode comprises a cathodically active material and has a coulombic capacity for the carrier ions, the negative electrode comprises anodically active silicon or an alloy thereof and has a coulombic capacity for the carrier ions that exceeds the positive electrode coulombic capacity, the control unit comprises a controller and a sensor electrically coupled to the sensor, the sensor is configured to measure a cell voltage of the secondary battery during operation of the secondary battery and to measure the voltage of the positive or negative electrode relative to the auxiliary electrode, the controller is programmed with a predefined cell end of charge voltage Vcell,eoc value and a predefined cell end of discharge voltage Vcell,eod value, and the positive electrode has an end of discharge voltage Vpos,eod and the negative electrode has an end of discharge voltage Vneg,eod when the cell is at the predefined Vcell,eod, the value of Vpos,eod corresponding to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li). ### Claim 26 (depends on 25) The secondary battery of claim 25 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of Vneg,eod is in excess of 0.9 V (vs Li) and when the secondary battery is at the predefined Vcell,eod value at the end of a discharge cycle of the secondary battery. ### Claim 27 (depends on 25) The secondary battery of claim 25 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of Vneg,eod is in excess of 0.5 V (vs Li) and when the secondary battery is at the predefined Vcell,eod value at the end of a discharge cycle of the secondary battery. ### Claim 28 (depends on 25) The secondary battery of claim 25 wherein the carrier ions are lithium, sodium, potassium, magnesium or aluminum ions. ### Claim 29 (depends on 25) The secondary battery of claim 25 wherein the carrier ions are lithium ions. ### Claim 30 (depends on 25) The secondary battery of claim 25 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 1.2:1, respectively, when cycled against a counter-electrode. ### Claim 31 (depends on 25) The secondary battery of claim 25 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 1.5:1, respectively, when cycled against a counter-electrode. ### Claim 32 (depends on 25) The secondary battery of claim 25 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 2:1, respectively, when cycled against a counter-electrode. ### Claim 33 (depends on 25) The secondary battery of claim 25 wherein a ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 5:1, respectively, when cycled against a counter-electrode. ### Claim 34 (depends on 25) The secondary battery of claim 25 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 1.2:1, respectively, when cycled against a counter-electrode. ### Claim 35 (depends on 25) The secondary battery of claim 25 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 1.5:1, respectively, when cycled against a counter-electrode. ### Claim 36 (depends on 25) The secondary battery of claim 25 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 2:1, respectively, when cycled against a counter-electrode. ### Claim 37 (depends on 25) The secondary battery of claim 25 wherein a ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode is at least 5:1, respectively, when cycled against a counter-electrode. ### Claim 38 (depends on 25) The secondary battery of claim 25 wherein the negative electrode comprises a silicon-containing active material that contains a significant void volume fraction to accommodate volume expansion and contraction as carrier ions are incorporated into or leave the negative electrode during charging and discharging cycles. ### Claim 39 (depends on 38) The secondary battery of claim 38 wherein the void volume fraction of the anodically active material is at least 0.1. ### Claim 40 (depends on 38) The secondary battery of claim 38 wherein the void volume fraction of the anodically active material is not greater than 0.8. ### Claim 41 (depends on 38) The secondary battery of claim 38 wherein the void volume fraction of the anodically active material is about 0.15 to about 0.75. ### Claim 42 (depends on 38) The secondary battery of claim 38 wherein the void volume fraction of the anodically active material is about 0.25 to about 0.6. ### Claim 43 (depends on 38) The secondary battery of claim 38 wherein the anodically active material comprises macroporous, microporous or mesoporous material layers or a combination thereof.