Replenished negative electrodes for secondary batteries

Patent metadata

Field	Value
Publication number	US-2018151920-A1
Application number	US-201615572191-A
Country	US
Kind code	A1
Filing date	May 6, 2016
Priority date	May 8, 2015
Publication date	May 31, 2018
Grant date	—

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 V pos,eod and a negative electrode end of discharge voltage V neg,eod when the cell is at a predefined V cell,eod value, the value of V pos,eod corresponding to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li).

First claim

What is claimed is:

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 V cell,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 V pos,eod and a negative electrode end of discharge voltage V neg,eod when the cell is at the predefined V cell,eod value, wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li).

2 . The process of claim 1 , wherein step (ii) is performed after or simultaneously with step (i).

3 . The process 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.

4 . The process 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.

5 . The process of claim 1 wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at V cell,eod .

6 . The process of claim 1 wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 96% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at V cell,eod .

7 . The process of claim 1 wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 97% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at V cell,eod .

8 . The process of claim 1 wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 98% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at V cell,eod .

9 . The process of claim 1 wherein the value of V pos,eod corresponds to a voltage at which the state of charge of the positive electrode is at least 99% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li) when the cell is at V cell,eod .

10 . The process of any of claims 1 to 9 wherein V neg,eod is at least 0.4 V (vs Li) but less than 0.8 V (vs Li) when the cell is at V cell,eod .

11 . The process of any of claims 1 to 9 wherein V neg,eod is at least 0.5 V (vs Li) but less than 0.8 V (vs Li) when the cell is at V cell,eod .

12 . The process of any of claims 1 to 9 wherein V neg,eod is at least 0.4 V (vs Li) but less than 0.7 V (vs Li) when the cell is at V cell,eod .

13 . The process of any of claims 1 to 9 wherein V neg,eod is at least 0.5 V (vs Li) but less than 0.7 V (vs Li) when the cell is at V cell,eod .

14 . 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 V cell,eoc value and a predefined cell end of discharge voltage V cell,eod value, and the positive electrode has an end of discharge voltage V pos,eod and the negative electrode has an end of discharge voltage V neg,eod when the cell is at the predefined V cell,eod , the value of V pos,eod corresponding to a voltage at which the state of charge of the positive electrode is at least 95% of its coulombic capacity and V neg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li).

15 . The secondary battery of claim 14 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of V neg,eod is in excess of 0.9 V (vs Li) when the secondary battery is the predefined V cell,eod value at the end of a discharge cycle of the secondary battery.

16 . The secondary battery of claim 14 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of V neg,eod is in excess of 0.8 V (vs Li) when the secondary battery is the predefined V cell,eod value at the end of a discharge cycle of the secondary battery.

17 . The secondary battery of claim 14 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of V neg,eod is in excess of 0.7 V (vs Li) when the secondary battery is the predefined V cell,eod value at the end of a discharge cycle of the secondary battery.

18 . The secondary battery of claim 14 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of V neg,eod is in excess of 0.6 V (vs Li) when the secondary battery is the predefined V cell,eod value at the end of a discharge cycle of the secondary battery.

19 . The secondary battery of claim 14 wherein controller is programmed to transfer carrier ions from the auxiliary electrode to the positive or negative electrode when the value of V neg,eod is in excess of 0.5 V (vs Li) when the secondary battery is the predefined V cell,eod value at the end of a discharge cycle of the secondary battery.

Assignees

• Enovix Corp

Inventors

• Castledine Christopher G
• Fouchard David T
• Doan Jonathan C
• Spindt Christopher J
• Spotniz Robert M
• Wilcox James D
• Lahiri Ashok
• Ramasubramanian Murali

Classifications

• H01M10/446 Primary

  Initial charging measures · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/48

  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) · CPC title

• H01M10/448 Primary

  End of discharge regulating measures · CPC title