Supplementary negative electrode for secondary batteries

Abstract

A method for activating a secondary battery is provided, the secondary battery having a negative electrode, a positive electrode, and an electrolyte containing carrier ions infiltrated between the negative electrode and the positive electrode, the negative electrode having anode-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 the auxiliary electrode to the positive electrode to provide the secondary battery with a positive electrode discharge end voltage V pos,eod and negative electrode discharge end voltage V neg,eod , when the primitive is at a predetermined V cell,eod When V pos,eod The value corresponds to a voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, and V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

Description

[0001] This application is a divisional application of a patent application with an application date of May 6, 2016, application number 201680039874.5, and name “Supplementary negative electrode for secondary battery”. Technical Field

[0002] The present disclosure generally relates to methods for replenishing energy storage devices and replenished energy storage devices, such as secondary batteries. Background Art

[0003] In a rocking chair battery cell, both the positive and negative electrodes include materials into which carrier ions (e.g., lithium) are inserted and extracted. When the cell is discharged, carrier ions are extracted from the negative electrode and inserted into the positive electrode. When the cell is charged, the reverse process occurs: carrier ions are extracted from the positive electrode and inserted into the negative electrode.

[0004] Silicon has become a promising candidate for the role of an anode for rechargeable secondary batteries as an alternative to carbonaceous materials due to its ultra-high capacity. Large volume increases of more than 300% have been observed for bulk silicon upon insertion of carrier ions (e.g., lithium ions). This volume increase, along with cracking and pulverization during charge and discharge cycles, limits the use of bulk silicon anodes in practice.

[0005] When an energy storage device such as a secondary battery is assembled, the amount of carrier ions available for circulation between the anode and the cathode is typically initially provided in the cathode, because cathode active materials such as lithium cobalt oxide are relatively stable (e.g., resistant to oxidation) in ambient air compared to lithiated anode materials such as lithiated graphite. When the secondary battery is charged for the first time, carrier ions are extracted from the cathode and introduced into the anode. As a result, the anode potential drops significantly (towards the potential of the metal carrier ions), and the cathode potential rises further (even becoming more positive). These potential changes may cause parasitic reactions on both electrodes, but sometimes they are more severe on the anode. For example, decomposition products containing lithium (or other carrier ions) and electrolyte components (known as solid electrolyte interface (SEI)) are easily formed on the surface of the carbon anode. These surface layers or covering layers are carrier ion conductors that establish ionic connections between the anode and the electrolyte and prevent further reaction.

[0006] Although the formation of the SEI layer is necessary for the stability of the half-cell system including the anode and the electrolyte, a portion of the carrier ions introduced into the cell by the cathode are irreversibly bound and therefore removed from the cycling operation (i.e., from the capacity available to the user). As a result, during the initial discharge, fewer carrier ions are returned from the anode to the cathode than initially provided by the cathode during the initial charging operation, which results in an irreversible capacity loss. During each subsequent charge and discharge cycle, the capacity loss to the anode and / or cathode due to mechanical and / or electrical degradation tends to be smaller in each cycle, but as the battery ages, even a relatively small loss of carrier ions per cycle significantly reduces the energy density and cycle life. In addition, chemical and electrochemical degradation may also occur on the electrodes and result in capacity loss. Summary of the invention

[0007] In various aspects of the present disclosure, energy storage devices, such as secondary batteries, fuel cells, and electrochemical capacitors, are provided in which capacity lost due to SEI formation and / or mechanical or electrical degradation of the negative electrode and / or the positive electrode may be recovered. Advantageously, the energy storage devices of the present disclosure provide increased cycle life, higher energy density, and / or increased discharge rate.

[0008] Therefore, in brief, one aspect of the present disclosure relates to a method for activating a secondary battery having a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode permeated with an electrolyte containing carrier ions in ionic contact with the negative electrode and the positive electrode, and a battery programmed with a predetermined discharge end voltage V cell,eod The method comprises: (i) transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery, wherein a solid electrolyte interface is formed on the surface of the negative electrode during the transfer, and (ii) transferring carrier ions from the auxiliary electrode to the positive electrode to charge the secondary battery when the cell is at a predetermined V cell,eod When the positive electrode discharge end voltage V is provided to the secondary battery pos,eod and negative electrode discharge end voltage V neg,eod , V pos The value of corresponds to a voltage at which the positive electrode has a state of charge of at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0009] Another aspect of the present invention is a method for activating a secondary battery, the secondary battery having a negative electrode, a positive electrode, a microporous membrane between the negative electrode and the positive electrode permeated with an electrolyte containing carrier ions in ionic contact with the positive electrode and the negative electrode, and a control unit, wherein the positive electrode includes a cathode active material and has a reversible coulombic capacity for carrier ions, and the negative electrode has an anode active silicon or an alloy thereof and has a reversible coulombic capacity for carrier ions that exceeds the coulombic capacity of the positive electrode. The method comprises: (i) transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery, wherein a solid electrolyte interface (interphase) is formed on the surface of the negative electrode during the transfer; (ii) after step (i), transferring carrier ions from an auxiliary electrode to the positive electrode, (iii) after step (ii), transferring carrier ions from the positive electrode to the negative electrode to charge the secondary battery, and (iv) programming the control unit to set a cell discharge end voltage V cell,eod , where when the primitive is at V cell eod When the activated secondary battery has a positive electrode discharge end voltage V pos,eod and negative electrode discharge end voltage V neg,eod The positive electrode terminal, V pos,eod The value of corresponds to a voltage at which the positive electrode has a state of charge of at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0010] Another aspect of the present disclosure is a method for charging a secondary battery, the secondary battery having: a negative electrode, a positive electrode and a microporous separator between the negative electrode and the positive electrode, the electrolyte containing carrier ions in contact with the negative electrode and the positive electrode being infiltrated, and the negative electrode having anode-active silicon or its alloy, the positive electrode having cathode-active material, wherein the ratio of the coulombic capacity of the negative electrode to the coulombic capacity of the positive electrode is at least 1.2:1, respectively. The method comprises: (i) transferring carrier ions from an auxiliary electrode to the positive electrode, and (ii) charging the negative electrode with the carrier ions transferred from the auxiliary electrode to the positive electrode, thereby charging the secondary battery, the charged secondary battery having a discharge end voltage V cell,eod and negative electrode discharge end voltage V neg,eod , when V cell,eod When V neg,eod Less than 0.9V (vs Li) and at least 0.4V (vs Li).

[0011] Another aspect of the present disclosure is a secondary battery having: a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode, the separator being permeated with an electrolyte containing carrier ions in ionic contact with the negative electrode and the positive electrode, an auxiliary electrode, and a control unit. The positive electrode includes a cathode active material and has a coulomb capacity for carrier ions. The negative electrode includes an anode active silicon or an alloy thereof and has a coulomb capacity for carrier ions exceeding the coulomb capacity of the positive electrode. The control unit has a controller and a sensor electrically coupled to the sensor, the sensor being configured to: measure the cell voltage of the secondary battery during operation of the secondary battery, and to measure the voltage of the positive electrode or the negative electrode relative to the auxiliary electrode, the controller being programmed to: upon detecting a cell charge end voltage V cell,eoc When the charging operation of the secondary battery is ended, and when the cell discharge end voltage V is detected cell_eod When the discharge operation of the secondary battery is terminated. In addition, when the battery is at V cell,eod When the positive electrode has a discharge end voltage V pos,eod , and the negative electrode has a discharge end voltage V neg,eod , the V pos,eod The value of corresponds to a voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0012] Other objects and features will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is an exemplary charge / discharge cycle of a silicon-containing negative electrode.

[0014] Figure 1A is with Figure 1 Exemplary charge / discharge cycles of the positive electrode matching the discharge capacity of the silicon-containing electrode.

[0015] Figure 2 is an exemplary charge / discharge cycle of a silicon-containing negative electrode.

[0016] Figure 2A is with Figure 2 The discharge capacity of the silicon-containing electrode matches the exemplary charge / discharge cycle of the positive electrode.

[0017] Figure 3 is an exemplary charge / discharge cycle of a silicon-containing negative electrode.

[0018] Figure 3A is with Figure 3Exemplary charge / discharge cycles of the positive electrode matching the discharge capacity of the silicon-containing electrode.

[0019] Figure 4 is an exemplary charge / discharge cycle of a silicon-containing negative electrode.

[0020] Figure 4A is with Figure 4 Exemplary charge / discharge cycles of the positive electrode matching the discharge capacity of the silicon-containing electrode.

[0021] Figure 5 is a schematic diagram of one embodiment of a secondary battery of the present disclosure.

[0022] Figure 6 is a schematic diagram of an alternative embodiment of a secondary battery of the present disclosure.

[0023] Figure 7 is a schematic diagram of an alternative embodiment of a secondary battery of the present disclosure.

[0024] Figure 8 is an exploded view of one embodiment of a secondary battery of the present disclosure.

[0025] Fig. 9 Is Figure 7 Schematic diagram of an electrode assembly constituting a secondary battery, with parts thereof cut away to reveal the internal structure.

[0026] Fig.10 is an exploded view of an alternative embodiment of the secondary battery of the present invention.

[0027] Fig.11 is a schematic diagram of an alternative embodiment of an electrode assembly including a secondary battery of the present disclosure.

[0028] Fig.12 is a schematic diagram of an alternative embodiment of an electrode assembly stack including a secondary battery of the present disclosure.

[0029] Corresponding reference characters indicate corresponding parts throughout the drawings. Specific embodiments

[0030] Unless the context clearly indicates otherwise, "a", "an", and "the" (i.e., singular form) used herein also refer to plural referents. For example, in one example, reference to "an electrode" includes a single electrode and multiple similar electrodes. The terms "comprising", "including", and "having" are intended to be inclusive and mean that there may be additional elements in addition to the listed elements.

[0031] As used herein, "about" and "approximately" refer to plus or minus 10%, 5%, or 1% of the value. For example, in one example, about 250 μm will include 225 μm to 275 μm. As another example, in one example, about 1,000 μm will include 900 μm to 1100 μm. Unless otherwise indicated, all numbers used in the specification and claims to indicate quantity (e.g., measurement, etc.) should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the attached claims are approximate values. Each numerical parameter should at least be interpreted according to the number of reported significant figures and by using ordinary rounding techniques.

[0032] As used herein, "state of charge" in the context of the state of a secondary battery refers to a state in which the secondary battery is charged to at least 75% of its rated capacity. For example, the battery may be charged to at least 80% of its rated capacity, at least 90% of its rated capacity, or even at least 95% of its rated capacity, such as 100% of its rated capacity.

[0033] The term "discharge capacity" as used herein with respect to the negative electrode refers to the amount of available carrier ions extracted from the negative electrode and inserted into the positive electrode during battery discharge operation between predetermined set cell end-of-charge and end-of-discharge voltage limits.

[0034] As used herein, "discharge state" in the context of the state of a secondary battery refers to a state in which the secondary battery is discharged to less than 25% of its rated capacity. For example, the battery may be discharged to less than 20% of its rated capacity, such as less than 10% of its rated capacity, or even less than 5% of its rated capacity, such as 0% of its rated capacity.

[0035] As used herein in the context of a secondary battery, "rated capacity" refers to the capacity of a secondary battery to deliver current over a period of time measured under standard temperature conditions (25°C). For example, the rated capacity can be measured in Amp hours, either by determining the current output for a specific time, or by determining the time a specific current can output the current, and multiplying the current by the time. For example, for a battery with a rated current of 20Amp·hr, if the rated current is 2 amperes, then the battery can be understood as a battery that can provide a current output for 10 hours, whereas if the time is specified at a rated value of 10 hours, the battery can be understood as a battery that will output 2 amperes in 10 hours.

[0036] The term "reversible coulombic capacity" as used herein with respect to an electrode (ie, positive electrode, negative electrode or auxiliary electrode) refers to the total capacity of the electrode that is available for reversible exchange of carrier ions with a counter electrode.

[0037] Specific description

[0038] In various aspects of the present disclosure, cell designs and formation methods for secondary batteries may be noted that provide a range of advantages, including, for example, improved cycle life, higher energy density, greater charge rates, and / or greater discharge rates. Typically, secondary batteries have a cell voltage limit for the charge / discharge cycle of the secondary battery, a positive electrode (cathode), and a negative electrode (anode), wherein the reversible coulombic capacity of the positive electrode matches the discharge capacity of the negative electrode after the battery is formed (i.e., after an initial charge / discharge cycle).

[0039] As previously described, the formation of a solid electrolyte interface (SEI) during the initial charge / discharge cycle reduces the amount of carrier ions available for reversible cycling. Mechanical and / or electrical degradation of the negative electrode during battery cycling can further reduce the amount of carrier ions available for reversible cycling. In order to compensate for the formation of the SEI (or another carrier ion consumption mechanism, such as mechanical and / or electrical degradation of the negative electrode), additional or supplemental carrier ions can therefore be provided from the auxiliary electrode after the battery is formed.

[0040] Generally, the voltage limit of a secondary battery cell and the relationship between the positive electrode and the negative electrode of the secondary battery are as follows:

[0041] V cell,eoc =V pos,eoc –V neg,eoc [1]

[0042] V cell,eod =V pos,eod –V neg,eod [2]

[0043] Where V cell,eoc is the charge end voltage for the cell, V pos,eoc is the charge end voltage for the positive electrode, V neg,eoc is the charge end voltage for the negative electrode, V cell,eod is the discharge end voltage for the cell, V pos,eod is the discharge end voltage for the positive electrode, V neg,eod is the discharge end voltage for the negative electrode.

[0044] Usually, V cell,eoc is the maximum value, since the cell voltage is ideally always at or below this value, and V cell,eod is the minimum value, because the cell voltage is ideally always equal to or higher than this value. By design, the cell voltage limit V cell,eoc and V cell，eodThe voltage limits of the positive and negative electrodes are fixed for the life of the battery, while the voltage limits of the individual electrodes may vary. Therefore, as used herein, it is understood that the designation of the positive and negative electrode voltage limits at the end of charge or discharge refers to the charge or discharge cycle after the battery is formed, i.e., after the first charge and discharge.

[0045] For the charging end voltage V of the positive active material for the secondary battery pos,eoc It can be as high as 5 V (vs.) Li, typically in the range of about 4.3 V to 4.5 V (vs. Li), and the discharge end voltage V of positive active materials commonly used in secondary batteries pos,end Will typically be at least 2.5 V (vs. Li). For a silicon-containing negative electrode, the end-of-charge voltage V neg,eoc Typically 0.1 V (vs. Li), and the end-of-discharge voltage is a matter of design choice, which is programmed into and controlled by the battery's control unit. Thus, according to equations [1] and [2], the cell charge end voltage V for a cell comprising this material is cell,eoc Typically at least about 4.2 V, at least about 4.4 V (vs. Li), or even greater values, and for such materials, the cell discharge end voltage V cell,eod Typically has 2.5V and V neg,eod (vs.Li) is the value determined by the difference between cell,eod =2.5VV neg,eod ).

[0046] In one embodiment of the present disclosure, when the secondary battery reaches the cell discharge end voltage V during the discharge cycle of the secondary battery (after the initial charge and discharge cycle when SEI is formed), cell,eod When the negative electrode discharge ends, the voltage V neg,eod is less than 0.9 V (vs. Li), and greater than 0.4 V (vs. Li). Thus, for example, in one such embodiment, when the secondary battery reaches the cell discharge end voltage V during the discharge cycle of the secondary battery (i.e., when the cell is under discharge load), the secondary battery reaches the cell discharge end voltage V cell,eod When the negative electrode discharge ends, the voltage V neg,eod As another example, in one such embodiment, when the secondary battery reaches the cell discharge end voltage V during the discharge cycle of the secondary battery (i.e., when the cell is under discharge load), the secondary battery reaches the cell discharge end voltage V cell,eod When the negative electrode discharge ends, the voltage V neg,eodThe voltage V may be in the range of about 0.6 V (vs. Li) to about 0.8 V (vs. Li). In one such embodiment, when the secondary battery reaches the cell discharge end voltage V during the discharge cycle of the secondary battery (i.e., when the cell is under discharge load), the secondary battery reaches the cell discharge end voltage V cell,eod When the negative electrode discharge ends, the voltage V neg,eod It may be in the range of about 0.6 V (vs. Li) to about 0.7 V (vs. Li).

[0047] Figure 1-4 An exemplary charge / discharge cycle for a silicon-containing negative electrode is shown. The end-of-charge voltage V neg,eoc is 0.1V (vs.Li), and the discharge end voltage V neg,eod 0.9V( Figure 1 )、0.8V( Figure 2 )、0.7V( Figure 3 ) or 0.6V( Figure 4 )(vs.Li). The discharge capacity of silicon-containing electrodes with these end-of-charge limitations is determined by C a ( Figure 1 ), C b ( Figure 2 ), C c ( Figure 3 ) and C d ( Figure 4 ) is given. Compare Figure 1-4 As shown in the figure, the discharge capacity of each silicon-containing electrode increases with the discharge end voltage V neg,eod As the value of decreases (for a constant reversible coulombic capacity), the discharge capacity of the electrode decreases.

[0048] like Figure 1-4 As shown in FIG. 1 , a discharge end voltage value of less than 0.4 V (vs. Li) reduces the energy density of the entire cell and is therefore not preferred. A V of at least 0.9 V (vs. Li) neg,eod Values ​​of 100 provide significantly greater overall cell energy density, but tend to reduce cycle life and are generally not preferred. According to one aspect of the present disclosure, the discharge end voltage V for a lithium ion battery including a silicon-containing electrode is neg,eod Less than 0.9V (vs. Li). For example, in one such embodiment, V neg,eod As a further example, in one such embodiment, V neg,eod As a further example, in one such embodiment, V neg,eod As another example, in one such embodiment, V neg,eodNo more than 0.5V (vs. Li). In one such exemplary embodiment, V neg,eod More than 0.4V, but less than 0.9V (vs. Li). As another example, in one such embodiment, V neg,eod In the range of about 0.5V to about 0.8V (vs. Li). As another example, in one such embodiment, V neg,eod In the range of about 0.6V to about 0.8V (vs. Li). In one such exemplary embodiment, V neg,eod In the range of about 0.6V to about 0.7V (vs. Li).

[0049] Generally, the positive electrode of the secondary battery of the present disclosure preferably has a reversible coulombic capacity that matches the discharge capacity of the negative electrode. In other words, the size of the cathode is designed to have a reversible coulombic capacity corresponding to the discharge capacity of the negative electrode, which in turn is the negative electrode discharge end voltage V neg,eod Function (see Figure 1-4 ). For example, now refer to Figure 1A-4A , the reversible coulombic capacity of the positive electrode is matched to the discharge capacity of the negative electrode, which has Figure 1-4 C e ( Figure 1A ), C f ( Figure 2A ), C g ( Figure 3A ) and C h ( Figure 4A ) gives the discharge end voltage limit. Figure 1A-4A , it can be observed that the reversible coulomb capacity of the positive electrode matching the discharge capacity of the negative electrode increases with the discharge end voltage V for the negative electrode (with a constant reversible coulomb capacity). neg,eod decreases with the decrease of value.

[0050] In one embodiment, the reversible capacity of the positive electrode matches the discharge capacity of the negative electrode so that when V cell,eod When the positive electrode has V pos,eod A value corresponding to a voltage at which the state of charge of the positive electrode is at least 95% of its reversible coulombic capacity and Vneg,eod is at least 0.4 V (vs Li) but less than 0.9 V (vs Li). For example, in one such embodiment, when V cell,eod When the positive electrode has such a V pos,eod value, the V pos,eod The value corresponds to a state of charge of the positive electrode of at least 96% of its reversible coulombic capacity and V neg,eodAs a further example, in one such embodiment, when V cell,eod When the positive electrode has V pos,eod value, which corresponds to a state of charge of the positive electrode of at least 97% of its reversible coulombic capacity and V neg,eod A voltage of at least 0.4 V (vs Li) but less than 0.9 V (vs Li). By way of further example, in one such embodiment, when V cell,eod When the positive electrode has V pos,eod value, which corresponds to a state of charge of the positive electrode of at least 98% of its reversible coulombic capacity and V neg,eod A voltage of at least 0.4 V (vs Li) but less than 0.9 V (vs Li). As a further example, in one such embodiment, when V cell,eod When the positive electrode has V pos,eod value, which corresponds to a state of charge of the positive electrode of at least 99% of its reversible coulombic capacity and V neg,eod A voltage of at least 0.4 V (vs Li) but less than 0.9 V (vs Li).

[0051] According to one aspect of the present disclosure, the negative electrode is designed to have a reversible coulombic capacity that significantly exceeds the reversible coulombic capacity of the positive electrode. For example, in one embodiment, the 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. As another example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 1.3:1. As another example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 2:1. As another example, in one embodiment, the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 3:1. As another example, the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 4:1. As another example, the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode is at least 5:1. Advantageously, the excess coulombic capacity of the negative electrode provides a source of anode active material to allow the battery to operate reversibly within a specific voltage that inhibits the formation of a crystalline phase (bound carrier ions) at the negative electrode, which reduces the cycle life of the negative electrode (and thus the battery) as the battery cycles. Additionally, the excess anode coulombic capacity and reduced negative electrode voltage on discharge provide a battery with greater energy density (due to a greater average voltage).

[0052] Typically, the carrier ions can be any carrier ions suitable for secondary batteries. In a preferred exemplary embodiment, as the secondary battery is charged and discharged, the secondary battery utilizes carrier ions selected from such as lithium ions, sodium ions, potassium ions, calcium ions, magnesium ions and aluminum ions that circulate between the components of the electrode and the electrode population. For example, in one such embodiment, the carrier ions are lithium ions. As a further example, in another such embodiment, the carrier ions can be magnesium ions. As a further example, in another such embodiment, the carrier ions can be aluminum ions.

[0053] Reference now Figure 5 , an embodiment of a secondary battery of the present disclosure, generally labeled 10, is shown. The battery 10 includes at least one positive electrode structure 20, at least one negative electrode structure 22, an auxiliary electrode 24 that can be selectively electrically connected or coupled to the positive electrode structure 20 (e.g., by a switch 32), and a control unit (not shown) within a battery housing 11. The auxiliary electrode 24 shown in the head space of the battery 10 can be set at other locations as needed. The connectors 26, 28, 30 enable the positive electrode, the negative electrode, and the auxiliary electrode to be connected to an external battery terminal (not shown) to connect to an energy source or a consumer, and the switch 32 enables electrical connection between the positive electrode structure 20 and the auxiliary electrode 24. The control unit includes a sensor for sensing the cell voltage (i.e., the voltage between the positive electrode and the negative electrode) and for sensing the voltage of the positive electrode, the negative electrode, or both the positive electrode and the negative electrode relative to the auxiliary electrode. The control unit also includes a controller for controlling the charge and discharge cycle of the battery in response to the voltage sensed by the sensor.

[0054] The battery housing 11 may be made of any one or some of a range of materials commonly used in secondary batteries. For example, in one embodiment, the battery housing 11 may be made of a plastic material or a plastic foil laminate (e.g., an aluminum foil provided between a polyolefin layer and a polyester layer). Alternatively, the battery housing 11 may be made of stainless steel, titanium, aluminum, or other metals or alloys thereof.

[0055] In one embodiment, the positive electrode structure 20 includes any one or some of a series of cathode active materials capable of storing lithium or other carrier ions. For example, the positive electrode can include a cathode active material selected from transition metal oxides, transition metal sulfides, transition metal nitrides, lithium transition metal oxides, lithium transition metal sulfides, and lithium transition metal nitrides. The transition metal elements of these transition metal oxides, transition metal sulfides, and transition metal nitrides can include metal elements with d-shells or f-shells. Specific examples of these metal elements are Sc, Y, lanthanides, actinides, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pb, Pt, Cu, Ag, and Au. Additional cathode active materials include LiCoO2, LiNi 0.5 Mn 1.5 O4、Li(Ni x Co y The cathode active material may be deposited to form a positive electrode structure by any of a series of techniques including, for example, electrophoretic deposition, electrodeposition, co-deposition or slurry deposition. In an exemplary embodiment, one of the aforementioned cathode active materials in particulate form or a combination thereof is electrophoretically deposited. In another exemplary embodiment, a cathode active material such as V2O5 is electrodeposited. In another exemplary embodiment, one of the aforementioned cathode active materials in particle form or a combination thereof is co-deposited in a conductive matrix such as polyaniline. In another exemplary embodiment, one of the aforementioned cathode active materials in particle form or a combination thereof is deposited in a slurry.

[0056] The negative electrode structure 22 comprises a silicon-containing anode active material. In one embodiment, the negative electrode structure 22 comprises silicon, a silicon alloy, a mixture of silicon and another anode active material, a mixture of silicon and an electrochemically inert material, or a combination thereof. For example, in one exemplary embodiment, the negative electrode structure 22 comprises silicon or a combination of silicon and the following, carbon, germanium; selenium; nickel copper, tin, manganese, bismuth, silver, gold, zinc, lead and / or lead. As another example, in one such exemplary embodiment, the negative electrode structure 22 comprises silicon; silicon and germanium; silicon and carbon; silicon and selenium; silicon, selenium and carbon; a mixture of silicon and nickel and / or copper, or a combination thereof. In one exemplary embodiment, the negative electrode structure 22 comprises silicon or its oxide or nitride, its fluoride or other alloy. In another exemplary embodiment, the negative electrode structure 22 comprises silicon or its alloy. In each of the embodiments and examples described in this paragraph, the negative electrode structure 22 can be a particle agglomerated electrode or a monolithic electrode. The negative electrode structure 22 may be formed using methods such as electrodeposition, electrophoretic deposition, vapor deposition, catalyst-based growth such as gas-liquid-solid deposition, gel casting, tape casting, patterning, and slurry deposition followed by densification by methods such as sintering, bonding, and the like.

[0057] In one embodiment, the negative electrode structure 22 includes a microstructured silicon-containing active material that contains a significant void volume fraction to accommodate volume expansion and contraction caused by carrier ions being incorporated into or leaving the negative electrode structure 22 during charge and discharge cycles. Typically, the void volume fraction of the anode active material is at least 0.1. However, typically, the void volume fraction of the anode active material is no greater than 0.8. For example, in one embodiment, the void volume fraction of the anode active material is about 0.15 to about 0.75. As another example, in one embodiment, the void volume fraction of the anode active material is about 0.2 to about 0.7. By way of further example, in one embodiment, the void volume fraction of the anode active material is about 0.25 to about 0.6.

[0058] Depending on the composition of the microstructured anode active material and its formation method, the microstructured anode active material may include a macroporous, microporous or mesoporous material layer or a combination thereof, such as a combination of micropores and mesopores, or a combination of mesopores and macropores. Microporous materials are generally characterized by pore sizes less than 10nm, wall sizes less than 10nm, pore depths of 1-50 microns, and pore morphology generally characterized by "sponge-like" and irregular appearance, non-smooth walls, and branched pores. Mesoporous materials are typically characterized by pore sizes of 10-50nm, wall sizes of 10-50nm, pore depths of 1-100 microns, and pore morphology generally characterized by branched pores that are slightly well defined or dendritic pores. Macroporous materials are generally characterized by pore sizes greater than 50nm, wall sizes greater than 50nm, pore depths of 1-500 microns, and pore morphology that can be varied, straight, branched or dendritic and smooth or rough. In addition, the void volume may include open or closed voids or a combination thereof. In one embodiment, the void volume includes open voids, that is, the anode active material contains voids having openings on the side surfaces of the anode active material (i.e., the surfaces facing the separator and the cathode active material), and lithium ions (or other carrier ions) can enter or leave the anode active material through the openings; for example, lithium ions can enter the anode active material through the void openings after leaving the cathode active material. In another embodiment, the void volume includes closed voids, that is, the anode active material contains voids surrounded by the anode active material. Generally, open voids can provide a larger interfacial surface area for carrier ions, while closed voids are often less susceptible to the solid electrolyte interface ("SEI"), and each provides space for the expansion of the anode active material when carrier ions enter. Therefore, in certain embodiments, the anode active material preferably contains a combination of open and closed voids.

[0059] In one embodiment, the negative electrode structure 22 comprises porous silicon or an alloy thereof. The porous silicon layer can be formed, for example, by anodization, by etching (e.g., by depositing a noble metal such as gold, platinum, silver, or gold / palladium on the (100) surface of single crystal silicon and etching the surface with a mixture of hydrofluoric acid and hydrogen peroxide), or by other methods known in the art such as patterned chemical etching. In addition, as previously described, the porous anode active material typically has a porosity fraction of at least about 0.1 but less than 0.8.

[0060] In another embodiment, the negative electrode structure 22 includes fibers of silicon or its alloys. A single fiber may have a diameter (thickness dimension) of about 5 nm to about 10,000 nm. The fibers (nanowires) of silicon may be formed, for example, by chemical vapor deposition or other techniques known in the art such as gas-liquid-solid (VLS) growth and solid-liquid-solid (SLS) growth. In addition, as previously described, the anode active material 22 typically has a porosity fraction of at least about 0.1 but less than 0.8.

[0061] In one embodiment, the dimensions of the positive electrode and the negative electrode are determined so that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 120% of the reversible coulombic capacity of the positive electrode. For example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are set so that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 130% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are determined so that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 200% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are set so that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 300% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are determined such that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 400% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are set such that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is at least 500% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the dimensions of the positive electrode and the negative electrode are set such that after formation, when cycled relative to a reference electrode, the reversible coulombic capacity of the negative electrode is about 120% to about 175% of the reversible coulombic capacity of the positive electrode, or even about 120% to about 150% of the reversible coulombic capacity of the positive electrode.

[0062] The positive electrode structure 20 and the negative electrode structure 22 can be configured as flat or planar components of the battery 10, can be wound in a spiral or other configuration, and can be configured in a folded configuration; for example, the electrodes can be wound around a relatively rectangular mandrel so that they form an elliptical winding coil for insertion into a relatively prismatic battery case.

[0063] The auxiliary electrode contains a source of carrier ions to replenish the lost energy capacity after the battery is formed (i.e., to compensate for the loss of carrier ions that form the SEI and other carrier ion losses in the first charge and / or discharge cycle). The auxiliary electrode may include a foil of carrier ions in metal form (e.g., a foil of lithium, magnesium, or aluminum), or any of the aforementioned positive or anode active materials in the form of carrier ions. For example, the auxiliary electrode may include lithiated silicon or a lithiated silicon alloy. The auxiliary electrode may be formed by placing an electrode made of the desired material in an inactive region of the battery cell, but still coupled to the negative electrode and / or the positive electrode through a diaphragm electrolytically. Alternatively, the auxiliary electrode may be formed by depositing the desired auxiliary electrode material using, for example, electrochemical deposition, electroless deposition, electrophoretic deposition, vacuum assisted filling, template assisted filling, dip coating, etc.

[0064] In one embodiment, the auxiliary electrode is sized to provide at least 15% of the reversible coulombic capacity of the positive electrode. For example, in one such embodiment, the auxiliary electrode is sized to include enough carrier ions (e.g., lithium ions, magnesium ions, or aluminum ions) to provide at least 30% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the auxiliary electrode is sized to include enough carrier ions to provide at least 100% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the auxiliary electrode is sized to include enough carrier ions to provide at least 200% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the auxiliary electrode is sized to include enough carrier ions to provide at least 300% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the auxiliary electrode is sized to include enough carrier ions to provide about 100% to about 200% of the reversible coulombic capacity of the positive electrode.

[0065] Once the cell is assembled, it is charged by transferring charge carrier ions from the positive electrode to the negative electrode. pos,eoc When the designed value is reached, the charging is stopped. During the initial charging cycle, SEI is easily formed on the surface of the negative electrode structure. In order to compensate for the loss of carrier ions to SEI, and again refer to Figure 5 , the positive electrode structure 20 can be replenished by closing the switch 32 and applying a voltage across the auxiliary electrode 24 and the positive electrode structure 20 to drive the carrier ions from the auxiliary electrode to the positive electrode. Once the transfer of the carrier ions from the auxiliary electrode to the positive electrode is complete, the negative electrode is charged again, this time with the carrier ions transferred from the auxiliary electrode, until V is reached. cell,eoc value, which typically corresponds to a V of about 0.1V neg,eoc The value is equal to Vcell and 0.1V (vs Li) is the sum of V pos,eoc value.

[0066] In yet another embodiment, the positive electrode may be replenished with carrier ions by simultaneously transferring carrier ions from the auxiliary electrode to the positive electrode and also transferring carrier ions from the positive electrode to the negative electrode. Figure 5 , a voltage is applied across the positive electrode structure 20 and the negative electrode structure 22 to drive the carrier ions from the positive electrode structure 20 to the negative electrode structure 22. When the carrier ions are transferred from the positive electrode structure 20 to the negative electrode structure 22, the switch 32 can be closed and a voltage is applied across the auxiliary electrode 24 and the positive electrode structure 20 to drive the carrier ions from the auxiliary electrode 24 to the positive electrode structure 20. Therefore, at the same time as the carrier ions are transferred from the positive electrode structure 20 to the negative electrode, the carrier ions move from the auxiliary electrode 24 to the positive electrode structure 20. That is, the voltage across the positive electrode structure 20 and the negative electrode structure 22 is maintained sufficient to drive the carrier ions from the positive electrode structure 20 to the negative electrode structure 22, while the voltage maintained across the auxiliary electrode 24 and the positive electrode structure 20 is maintained sufficient to drive the carrier ions from the auxiliary electrode to the positive electrode structure. In one embodiment, the switch 32 may be closed and a voltage may be applied across the auxiliary electrode 24 and the positive electrode structure 20 to drive the carrier ions to the positive electrode structure 20 at a time t1, which is a predetermined duration after the voltage t0 applied across the positive electrode structure 20 and the negative electrode structure 22 to drive the carrier ions to the negative electrode structure occurs. That is, the occurrence of the transfer of the carrier ions from the positive electrode structure 20 to the negative electrode structure 22 may begin at an initial time t0, with the transfer of the carrier ions from the auxiliary electrode 24 to the positive electrode structure 20 occurring at a time t1 a predetermined time after t0, such that in the time period after t1, the carrier ions are transferred from the auxiliary electrode 24 to the positive electrode structure 20 while the carrier ions are transferred from the positive electrode structure to the negative electrode structure 22. In another embodiment, the occurrence of the transfer of the carrier ions from the auxiliary electrode 24 to the positive electrode structure 20 may begin simultaneously with the occurrence of the transfer of the carrier ions from the positive electrode structure 20 to the negative electrode structure 22, for example at time t0. Similarly, in one embodiment, the transfer of carrier ions from the auxiliary electrode 24 to the positive electrode structure 20 can be stopped at a time t2, which is the same as the time when the transfer of carrier ions from the positive electrode structure 20 to the negative electrode is stopped, and / or the transfer of carrier ions from the auxiliary electrode 24 can be stopped at such a time t2, which is a predetermined time before the moment t3 when the transfer of carrier ions from the positive electrode structure 20 to the negative electrode structure 22 is stopped.

[0067] In one embodiment, the transfer rate of carrier ions from the positive electrode structure 20 to the negative electrode structure 22 is greater than or equal to the transfer rate of carrier ions from the auxiliary electrode 24 to the positive electrode structure 20, so that a good overall transfer rate of carrier ions from the auxiliary electrode 24 via the positive electrode structure 20 to the negative electrode structure 22 can be maintained. That is, the relative transfer rates between the positive electrode structure 20 and the negative electrode structure 22 and the auxiliary electrode 24 and the positive electrode structure 20 can be maintained so that the overall capacity of the positive electrode structure 20 for additional carrier ions is not exceeded. The positive electrode structure 20 can thus be maintained in a state in which it has the ability to accept new carrier ions from the auxiliary electrode 24, which can allow the carrier ions to be subsequently transferred to the negative electrode structure 22. For example, in one embodiment, the voltage applied across the positive electrode structure 20 and the negative electrode structure 22 and the voltage applied across the auxiliary electrode 24 and the positive electrode structure 20 are selected to provide a transfer rate of carrier ions between the positive electrode structure and the negative electrode structure 22 that is greater than or equal to the transfer rate of carrier ions between the auxiliary electrode 24 and the positive electrode structure 20. The carrier ion transfer rate between the electrodes can be related to the current between the electrodes, which can be measured using a sensor, for example. Therefore, in one example, the current between the auxiliary electrode 24 and the positive electrode structure 20 is lower than the current between the positive electrode structure 20 and the negative electrode structure 22, which reflects the lower transfer rate of carrier ions between the auxiliary electrode 24 and the positive electrode structure 20 compared to the transfer rate of carrier ions between the positive electrode structure 20 and the negative electrode structure 22. For example, in one embodiment, the current between the auxiliary electrode 24 and the positive electrode structure 20 can be 80% or less of the current between the positive electrode structure 20 and the negative electrode structure 22. As another example, in one embodiment, the current between the auxiliary electrode 24 and the positive electrode structure 20 can be 60% or less of the current between the positive electrode structure 20 and the negative electrode structure 22. In another example, in one embodiment, the current between the auxiliary electrode 24 and the positive electrode structure 20 can be 50% or less of the current between the positive electrode structure 20 and the negative electrode structure 22. As another example, in one embodiment, the current between the auxiliary electrode 24 and the positive electrode structure 20 may be 30% or less of the current between the positive electrode structure 20 and the negative electrode structure 22. As yet another example, in one embodiment, the current between the auxiliary electrode 24 and the positive electrode structure 20 may be 20% or less of the current between the positive electrode structure 20 and the negative electrode structure 22.

[0068] In one embodiment, without being limited to any particular theory, carrier ions are transferred from the auxiliary electrode 24 to the positive electrode structure 20 as part of the supplementation of the negative electrode structure 22 (rather than directly from the auxiliary electrode 24 to the negative electrode structure 22) because the positive electrode structure 20 may be able to more uniformly accept carrier ions across its surface, thereby allowing the carrier ions to more uniformly participate in their transfer between the positive electrode structure 20 and the negative electrode structure 22. In contrast, for certain materials used to form the negative electrode structure 22 (such as silicon-containing materials), direct transfer of carrier ions from the auxiliary electrode 24 to the negative electrode structure 22 may result in uneven accumulation of carrier ions on its surface, such as on the surface of the negative electrode structure 22 closest to the auxiliary electrode 24, thereby limiting the ability of the accumulated carrier ions to uniformly participate in transfer between the positive electrode structure 20 and the negative electrode structure 22 during charging and discharging. Therefore, by transferring carrier ions from the auxiliary electrode 24 to the positive electrode structure 20, a more uniform carrier ion transfer to the negative electrode structure 22 may be provided, thereby improving the overall performance of the battery having the supplemented negative electrode structure 22.

[0069] Typically, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode (and then ultimately to the negative electrode) is sufficient to match the reversible capacity of the positive electrode with the discharge capacity of the negative electrode (where the reversible capacity of the positive electrode is equal to the discharge capacity of the negative electrode when the secondary battery reaches the cell discharge end voltage V cell,eod When the negative electrode discharge ends, the voltage V neg,eod Greater than 0.4V (vs Li) and less than 0.9V (vs Li)). In one embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 10% of the reversible capacity of the positive electrode. For example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 15% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 20% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 25% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 30% of the reversible coulombic capacity of the positive electrode. As another example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 40% of the reversible coulombic capacity of the positive electrode. As a further example, in one such embodiment, the amount of carrier ions transferred from the auxiliary electrode to the positive electrode is at least 50% of the reversible coulombic capacity of the positive electrode.

[0070] Reference again Figure 5, a porous separator (not shown) is located between the positive electrode structure 20 and the negative electrode structure 22 and between the auxiliary electrode 24 and the positive electrode structure and / or the negative electrode structure. The porous separator material may include any porous material conventionally used as a secondary battery separator, including, for example, microporous polyethylene, polypropylene, TiO2-polymer composites, SiO2, Al2O3, etc. (P. Arora and J. Zhang, "Battery Separators" Chemical Reviews 2004, 104, 4419-4462). Such materials can be deposited, for example, by electrophoretic deposition of particulate separator materials, slurry deposition of particulate separator materials (including spinning or spraying), or sputtering coating of ion-conductive particulate separator materials. In one embodiment, the porous separator material includes pores having a diameter of at least (More usually around range), and a porosity range of about 25% to about 75% (more typically about 35%-55%).

[0071] The porous separator material is permeated with a non-aqueous electrolyte that serves as a medium for conducting carrier ions between the positive electrode, the negative electrode, and the auxiliary electrode. Typically, the non-aqueous electrolyte can be any one or some of a series of non-aqueous electrolytes suitable for use as a secondary battery electrolyte. Typically, the non-aqueous electrolyte contains a salt of carrier ions such as a magnesium salt, an aluminum salt, or a lithium salt dissolved in an organic solvent. Exemplary lithium salts include inorganic lithium salts such as LiClO4, LiBF4, LiPF6, LiAsF6, LiCl, and LiBr; and LiB(C6H5)4, LiN(SO2CF3)2, LiN(SO2CF3)3, LiNSO2CF3, LiNSO2CF5, LiNSO2C4F9, LiNSO2C5F 11 、LiNSO2C6F 13 and LiNSO2C7F 15The organic lithium salt of the present invention is preferably selected from the group consisting of propylene carbonate, butylene carbonate, γ-butyrolactone, vinylene carbonate, 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone and γ-valerolactone. Specific examples of chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate, butyl propyl carbonate, alkyl propionate, dialkyl malonate, alkyl acetate. Specific examples of cyclic ethers include tetrahydrofuran, alkyltetrahydrofuran, dialkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane and 1,4-dioxolane. Specific examples of chain ethers include 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether. Other examples include alkoxy solutions with carrier ions, dichloro complex electrolytes, organic borates, organic halogenates, organic halogenated aluminates, Grignard organohaloaluminates, borohydrides, phenolates, and halides.

[0072] like Figure 5 As shown, the auxiliary electrode is a component of the finished secondary battery. In an alternative embodiment, the auxiliary electrode is removed from the secondary battery cell after supplementation of the positive electrode or negative electrode but before final packaging.

[0073] Including an auxiliary electrode in a secondary battery cell has important benefits in battery monitoring and maintenance. For example, the auxiliary electrode can be used as a reference electrode, and for accurate measurement of state of charge and health, and can measure the relationship between the cell voltage and state of charge over time, or when the voltage of the battery is relatively independent of the state of charge. For example, the auxiliary electrode can be used as a reference electrode to cut off the discharge when the voltage of the negative electrode exceeds a limit relative to the auxiliary electrode; in one such embodiment, this can be achieved by using a sensor to sense the voltage of the negative electrode relative to the auxiliary electrode, and then the controller will isolate the cell from the circuit it is powering when a predetermined voltage limit is exceeded.

[0074] In one embodiment, when the state of charge of one of the electrodes is not within a predetermined range, the auxiliary electrode may be accessed to transfer carrier ions to the positive electrode and / or the negative electrode to restore the predetermined state of charge. For example, if at some point in the service life of the secondary battery, the control unit detects that the negative electrode has a discharge end voltage V exceeding 0.9 V (vs. Li) neg,eod, the control unit can activate the transfer of carrier ions from the auxiliary electrode to the positive electrode and / or the negative electrode (as described above) so that V neg,eod As another example, if at some point in the life of the secondary battery, the control unit detects that the negative electrode has a discharge end voltage V exceeding 0.8 V (vs Li), neg,eod value, the control unit can activate the transfer of carrier ions from the auxiliary electrode to the positive electrode and / or the negative electrode (as described above) to increase V neg,eod As another example, if at some point in the life of the secondary battery, the control unit detects that the negative electrode has a discharge end voltage V exceeding 0.7 V (vs Li), neg,eod value, the control unit can activate the transfer of carrier ions from the auxiliary electrode to the positive electrode and / or the negative electrode (as described above) so that V neg,eod As another example, if at some point in the life of the secondary battery, the control unit detects that the negative electrode has a discharge end voltage V exceeding 0.6 V (vs. Li), neg,eod value, the control unit can activate the transfer of carrier ions from the auxiliary electrode to the positive electrode and / or the negative electrode (as described above) so that V neg,eod Recover to a value less than 0.6V (vs Li).

[0075] In an alternative embodiment, carrier ions can be transferred from the positive electrode to an auxiliary state of charge or balance electrode in order to restore a predetermined state of charge. For example, some positive electrode materials have a first cycle loss that significantly exceeds the first cycle of the elementary negative electrode. In such an embodiment, the difference in the first cycle loss of the positive electrode and the negative electrode can be compensated by providing a negative electrode having a reversible coulombic capacity that significantly exceeds the reversible coulombic capacity of the positive electrode. Alternatively or additionally, the difference in the first cycle loss can be accommodated by transferring carrier ions from the positive electrode to the auxiliary electrode during the formation of the battery.

[0076] Reference now Figure 6 In an alternative embodiment, the secondary battery 10 includes a plurality of positive electrode structures 20, a plurality of negative electrode structures 22, an auxiliary electrode 24, a control unit 27, and a substrate 29 supporting the positive electrode structures and the negative electrode structures. Each positive electrode structure includes a positive electrode current collector 21 and a cathode active material 120 on and in direct contact with the positive electrode current collector 21. Each negative electrode structure also includes a negative electrode current collector 23 and an anode active material 122 on and in direct contact with the negative electrode current collector 23. When the secondary battery 10 includes such Figure 6When the plurality of positive electrode structures 20 are shown, the positive electrode structures can be electrically coupled to each other. Figure 6 When a plurality of negative electrode structures 22 are shown, the negative electrode structures can be electrically coupled to each other. The control unit 27 includes a sensor for sensing the elementary voltage (i.e., the voltage difference between the positive electrode and the negative electrode) and for sensing the voltage difference between the auxiliary electrode and (i) the positive electrode, (ii) the negative electrode, or (iii) each of the positive electrode and the negative electrode. The control unit further includes a controller in communication with the sensor for controlling the charging and discharging operation of the battery, and the transfer of carrier ions from the auxiliary electrode to the positive electrode and / or the negative electrode, as described elsewhere herein.

[0077] In one embodiment, the anode active material 122 is in the form of a layer having a thickness of about 1 to about 100 microns. For example, in one embodiment, the anode active material 122 comprises porous silicon, having a thickness of about 5 to about 100 microns, and having a porosity fraction of about 0.15 to about 0.75. As another example, in one embodiment, the anode active material 122 comprises porous silicon, having a thickness of about 10 to about 80 microns, and having a porosity of about 0.15 to about 0.7. As another example, in one such embodiment, the anode active material 122 comprises porous silicon, having a thickness of about 20 to about 50 microns, and having a porosity fraction of about 0.25 to about 0.6. As another example, in one embodiment, the anode active material 122 comprises a porous silicon alloy (e.g., nickel silicide) having a thickness of about 5 to about 100 microns, and having a porosity of about 0.15 to about 0.75.

[0078] In an alternative embodiment, the anode active material 122 comprises silicon nanowires having a thickness of about 5 to about 100 microns and having a porosity fraction of about 0.15 to about 0.75. For example, in one such embodiment, the anode active material 122 comprises silicon nanowires having a thickness of about 10 to about 80 microns and having a porosity fraction of about 0.15 to about 0.7. As a further example, in one such embodiment, the anode active material 122 comprises silicon nanowires having a thickness of about 20 to about 50 microns and having a porosity fraction of about 0.25 to about 0.6. As another example, in one embodiment, the anode active material 122 comprises nanowires of a silicon alloy (e.g., nickel silicide) having a thickness of about 5 to about 100 microns and having a porosity fraction of about 0.15 to about 0.75.

[0079] The negative electrode current collector 23 will generally have a 3 Siemens / cm. For example, in one such embodiment, the negative electrode current collector 23 has a conductivity of at least about 10 4As a further example, in one such embodiment, the negative electrode current collector 23 has a conductivity of at least about 10 Siemens / cm. 5 Siemens / cm conductivity. Generally, the negative electrode current collector 23 can include any metal or other conductor commonly used as a current collector material for a negative electrode, such as carbon, cobalt, chromium, copper, nickel, titanium or an alloy of one or more thereof. The negative electrode current collector 23 can be manufactured by processes such as electrodeposition, electroless deposition, immersion deposition, physical vapor deposition, chemical vapor deposition, etc.

[0080] The separator 25 surrounds each component 20 of the positive electrode structure group and electrically isolates it from each component 22 of the negative electrode structure group, and includes a microporous separator material that can be permeated with a non-aqueous electrolyte as described above. For example, in one embodiment, the microporous separator material includes at least (More typically around ), and a porosity in the range of about 25% to about 75% (more typically in the range of about 35-55%).

[0081] The separator 25 also electrically isolates the auxiliary electrode 24 from the positive electrode structure 20 and the negative electrode structure 22. As shown, the separator 25 can include the same microporous material in the region between the auxiliary electrode 24 and the negative and positive electrode structures 20, 22 as in the region between the positive electrode structure 20 and the negative electrode structure 22. Alternatively, the separator 25 can include a microporous material in the region between the auxiliary electrode 24 and the negative and positive electrode structures 20, 22 that is different from the microporous material in the region between the positive electrode structure 20 and the negative electrode structure 22.

[0082] In those embodiments where the voltage difference between the auxiliary electrode and the positive electrode is greater than the voltage difference between the charge and discharge voltage limits between the auxiliary electrode and the negative electrode, the positive electrode can be replenished more quickly than the negative electrode. In addition, in those embodiments where the transfer of carrier ions involves a phase change reaction, i.e., when crystalline silicon is converted into amorphous silicon, the transfer of carrier ions directly from the auxiliary electrode to the negative electrode may produce an uneven concentration of carrier ions in the negative electrode (the carrier ions will tend to be concentrated at the position closest to the auxiliary electrode). Therefore, in such embodiments, it may be preferred to replenish the secondary battery by transferring carrier ions from the auxiliary electrode to the positive electrode and then to the negative electrode, rather than directly from the auxiliary electrode to the negative electrode. Nevertheless, there are some embodiments in which instead of (or in addition to) the positive electrode structure 20 (in addition to Figure 6It may be advantageous to electrically couple the auxiliary electrode 24 to the negative electrode structure 22 (as shown). For example, in one such embodiment, the auxiliary electrode 24 is electrically coupled to the negative electrode structure 22 and has the ability to function as an auxiliary negative electrode. The negative electrode structure 22 combined with the auxiliary negative electrode can achieve better performance than a single negative electrode.

[0083] As described above, the secondary battery 10 includes a group of negative electrode structures 22 and a group of positive electrode structures 20. Figure 6 As shown, in one embodiment, the components of the two groups are staggered and stacked in an alternating order (ie, negative electrode structure, positive electrode structure, negative electrode structure, positive electrode structure . . . ). For ease of illustration, Figure 6 , the number of positive electrode structure groups includes four components 20, and the negative electrode structure group includes three components 22; however, in practice, the negative electrode structure group and the positive electrode structure group may each include a greater or lesser number of components. For example, in one embodiment, the negative electrode structure group and the positive electrode structure group including the secondary element of the present disclosure may each include at least 5 components. As a further example, in one embodiment, the negative electrode structure group and the positive electrode structure group each include at least 10 components. As another example, in one embodiment, the negative electrode structure group and the positive electrode structure group each include at least 50 components. As a further example, in one embodiment, the negative electrode structure group and the positive electrode structure group each include at least 100 components.

[0084] like Figure 6 As shown, each component 22 of the negative electrode group is located between two components 20 of the positive electrode structure group, so that the staggered series begins and ends with the positive electrode structure 20, and each negative electrode structure 22 is located between two positive electrode structures 20 (e.g., a series of electrodes having the following repeating sequence: positive electrode, negative electrode, positive electrode, negative electrode, positive electrode...). For example, in one such embodiment, the negative electrode structure group has N components, the positive electrode structure group has N+1 components, each negative electrode is between two positive electrodes, and N is at least 5, at least 10, at least 25, at least 50, or even at least 100.

[0085] In an alternative embodiment, with one exception, each component 22 of the negative electrode structure group is between two components 20 of the positive electrode group, and with one exception, each component 20 of the positive electrode group is between two components 22 of the negative electrode group. More generally, in one embodiment, the positive electrode structure group and the negative electrode group each have N components, each of the N-1 positive electrode structures is between two negative electrode structures, each of the N-1 negative electrode structures is between two positive electrode structures, and N is at least 2. For example, in one embodiment, N is at least 4 (e.g., Figure 4as shown), at least 5, at least 10, at least 25, at least 50 or even at least 100.

[0086] In another alternative embodiment, for example, each component 20 of the positive electrode structure group is located between two components 22 of the negative electrode structure group, so that the interleaved series begins and ends with a negative electrode structure 22, and each positive electrode structure 20 is located between two negative electrode structures 22 (e.g., a series of electrodes having the following repeating order: negative electrode, positive electrode, negative electrode, positive electrode, negative electrode...). In one such embodiment, the positive electrode structure group has N components, the negative electrode structure group has N+1 components, each positive electrode structure is located between two negative electrode structures, and N is at least 5, at least 10, at least 25, at least 50, or even at least 100.

[0087] like Figure 6 As shown, the auxiliary electrode 24 is shown as an integral element. In some embodiments, the auxiliary electrode can include multiple auxiliary electrode elements or parts. For example, in one embodiment, the auxiliary electrode can include a lithium metal layer deposited (e.g., sputter deposited) onto the positive electrode current collector, the negative electrode current collector, a substrate supporting the positive electrode structure, a substrate supporting the negative electrode structure (see, e.g., Figure 6 ) or other surfaces or structures within a secondary battery such as a battery housing. In addition, the auxiliary electrode may be consumed during the battery formation process, or it may contain enough lithium so that the auxiliary electrode can be accessed after formation to provide additional lithium to the positive electrode or negative electrode structure.

[0088] Now refer to Figure 7 In an alternative embodiment, the secondary battery 10 includes an electrode assembly stack 74 and a control unit 27. In this embodiment, the electrode assembly stack 74 includes two electrode assemblies 75, each electrode assembly including a positive electrode structure 20 group, a negative electrode structure 22 group, a substrate 29 supporting the positive electrode structure and the negative electrode structure, and an auxiliary electrode 24. In this embodiment, the electrode assemblies are stacked relative to each other in a direction perpendicular to the planar substrate 29, and the positive electrode structure family and the negative electrode structure family are stacked relative to each other in a direction parallel to the planar substrate 29 within each electrode assembly 75. The control unit 27 is electrically connected to the positive electrode structure, the negative electrode structure, and the auxiliary electrode, and is operable to replenish each electrode assembly 75 with carrier ions, as described above. For ease of illustration, each electrode assembly 75 includes a group of two negative electrode structures and a group of two positive electrode structures; in practice, each of these groups may contain more components. In addition, in some embodiments, the substrate 29 can be omitted, in which case the stacking direction (as described in this paragraph) refers to an imaginary plane parallel to the substrate 29.

[0089] Reference now Figure 8In one embodiment, the secondary battery 10 of the present disclosure includes a battery housing 72, an electrode assembly stack 74, an auxiliary electrode 24, a negative electrode terminal 41 and a positive electrode terminal 42 for electrically connecting the electrode stack 74 to an external energy supply or consumer (not shown), and a control unit (not shown) including a sensor and a controller as described above. The electrode assembly stack 74 includes a group of six electrode assemblies 75 stacked vertically relative to each other, and the stacking direction is perpendicular to each electrode assembly 75 (see Fig. 9 ) in the stacking direction of the positive electrode and the negative electrode within the electrode assembly stack 74. The number of electrode assemblies 75 in the electrode assembly stack 74 is not critical and can be in the range of, for example, 1 to 50, with 2 to 20 electrode structures in the electrode stack being typical. After filling the battery housing with the non-aqueous electrolyte, the battery housing 72 can be sealed by a folding cover 72A at a hinge 72B and an adhesive cover 72A to an upper surface 72C. As described in more detail below, the auxiliary electrode 24 can be incorporated into the sealed secondary battery (i.e., as a component thereof), or alternatively, can be accessed during formation of the secondary battery and removed prior to sealing, as previously described.

[0090] The negative electrode tab extension 25 is electrically connected to each negative electrode structure 22 of each electrode assembly 75 (see Fig. 9 ), and the positive electrode tab extension 26 is electrically connected to each positive electrode structure 20 of each electrode assembly 75 (see Figure 8 ). Tab 41 may be electrically connected to negative electrode tab extension 25 using, for example, conductive glue, and tab 42 may be electrically connected to positive electrode tab extension 26 using, for example, conductive glue. Alternatively, tabs 41, 42 may be folded ends of negative electrode tab extension 25 and positive electrode tab extension 26, respectively.

[0091] Reference now Fig. 9 Each electrode assembly 75 includes a group of negative electrode structures 22 and a group of positive electrode structures 20 and a porous separator (not shown), such as a combination of Figure 5 and Figure 6 The components of the two groups are arranged in a direction D (a direction perpendicular to the stacking direction of the electrode assemblies 75 in the electrode assembly stack 74 (see Figure 7 )) are staggered and stacked in an alternating order.

[0092] Reference now Fig.10 In an alternative embodiment, the secondary battery 10 of the present disclosure is combined with Fig. 9 As otherwise described, however, two auxiliary electrode structures are included, one at the top and another at the bottom of the stack 74. The cell includes a control unit (not shown) which can be used to supplement each electrode assembly 75 from one or the other, or even both, auxiliary electrode structures, as previously described.

[0093] Now refer to Fig.11 In an alternative embodiment, the electrode assembly 75 includes an auxiliary electrode 24 and a group of positive electrode structures 20 and a group of negative electrode structures 22, each including a positive electrode skeleton (backbone) 80 and a negative electrode skeleton 82. In addition, in this embodiment, each component 20 of the group of positive electrode structures includes a collector 21 located between the skeleton 80 and the cathode active material 120, and each component 22 of the group of negative electrode structures includes a collector 23 located on its surface (i.e., at the interface between the anode active material 122 and the separator 25). The skeleton 80 and the cathode skeleton 82 provide mechanical stability for the cathode active material layer 120 and the anode active material layer 122, respectively. Typically, the skeleton will have a thickness of at least 1 micron. Depending on the application, the positive electrode skeleton 80 and the negative electrode skeleton 82 can be independently conductive or insulating.

[0094] Now refer to Fig.12 In an alternative embodiment, the electrode assembly stack 74 is combined with Figure 7 and Fig.11 As described further, however, in this embodiment, the electrode assembly stack 74 includes more auxiliary electrode structures 24 than electrode assemblies in the electrode assembly stack. As previously described, the battery includes a control unit (not shown) that can be used to supplement each electrode assembly 75 from one or more auxiliary electrode structures.

[0095] In further embodiments, numbered 1-84 below, aspects of the present disclosure include:

[0096] Embodiment 1. A method for activating a secondary battery, the secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode, the microporous separator being permeated with an electrolyte containing carrier ions in ionic contact with the positive electrode and the negative electrode, and a control unit, the negative electrode comprising anode active silicon or its alloy and having a coulombic capacity for carrier ions, the positive electrode comprising cathode active material and having a coulombic capacity for carrier ions, the negative electrode coulombic capacity exceeding the positive electrode coulombic capacity, the method comprising:

[0097] (i) transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery, wherein a solid electrolyte interface is formed on the surface of the negative electrode during the transfer,

[0098] (ii) after step (i), transferring carrier ions from the auxiliary electrode to the positive electrode,

[0099] (iii) after step (ii), transferring carrier ions from the positive electrode to the negative electrode to charge the secondary battery, and

[0100] (iv) Using a predetermined cell discharge end voltage Vcell,eod Value to () programming control unit,

[0101] The activated secondary battery has a positive electrode discharge end voltage V pos,eod and negative electrode discharge voltage V neg,eod , when the primitive is in the predefined V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0102] Embodiment 2. The method of embodiment 1, when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0103] Embodiment 3. The method of embodiment 1, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 96% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0104] Embodiment 4: The method of embodiment 1, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 97% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0105] Embodiment 5. The method of embodiment 1, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to a voltage at which the positive electrode has a state of charge of at least 98% of its Coulombic capacity and V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0106] Embodiment 6. The method of embodiment 1, wherein when the primitive is at V cell,eod When V pos,eod The value of V corresponds to the voltage at which the positive electrode is charged to at least 99% of its coulombic capacity, while V neg,eodAt least 0.4V (vsLi) but less than 0.9V (vs Li).

[0107] Embodiment 7: The method according to any one of embodiments 1 to 6, wherein when the primitive is at V cell,eod When V neg,eod At least 0.4V (vs Li) but less than 0.8V (vs Li).

[0108] Embodiment 8. The method of any one of Embodiments 1 to 6, wherein when the primitive is at V cell,eod When V neg,eod At least 0.5V (vs Li) but less than 0.8V (vs Li).

[0109] Embodiment 9. The method according to any one of embodiments 1 to 6, wherein when the primitive is at V cell,eod When V neg,eod At least 0.4V (vs Li) but less than 0.7V (vs Li).

[0110] Embodiment 10. The method according to any one of embodiments 1 to 6, wherein when the primitive is at V cell,eod When V neg,eod At least 0.5V (vs Li) but less than 0.7V (vs Li).

[0111] Embodiment 11. A secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode and permeated with an electrolyte containing carrier ions in contact with the negative electrode and the positive electrode ions, an auxiliary electrode and a control unit, wherein:

[0112] The positive electrode contains cathode active material and has a coulombic capacity for carrier ions,

[0113] The negative electrode comprises anodically active silicon or an alloy thereof and has a coulombic capacity for carrier ions exceeding the coulombic capacity of the positive electrode,

[0114] The control unit includes a controller and a sensor electrically coupled to the sensor,

[0115] The sensor is configured to measure a cell voltage of the secondary battery and measure a voltage of the positive electrode or the negative electrode relative to the auxiliary electrode during operation of the secondary battery,

[0116] The controller includes a predefined cell charging end voltage V cell,eoc value and the predetermined cell discharge end voltage V cell,eod value, and

[0117] When the battery is at a predetermined V cell,eod When the positive electrode has a discharge end voltage V pos,eod, and the negative electrode has a discharge end voltage V neg,eod , V pos,eod The value corresponds to the voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, and V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0118] Embodiment 12: The secondary battery according to Embodiment 11, wherein the controller is programmed to, when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value of the voltage exceeds 0.9 V (vs Li), the carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0119] Embodiment 13: The secondary battery according to Embodiment 11, wherein the controller is programmed to, when the secondary battery is at a predetermined V at the end of a discharge cycle of the secondary battery, cell,eod value, when V neg,eod When the value exceeds 0.8 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0120] Embodiment 14: The secondary battery according to embodiment 11, wherein the controller is programmed to, when the secondary battery is at a predetermined V at the end of a discharge cycle of the secondary battery, cell,eod value, when V neg,eod When the value exceeds 0.7 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0121] Embodiment 15: The secondary battery according to embodiment 11, wherein the controller is programmed to, when the secondary battery is at a predetermined V at the end of the discharge cycle of the secondary battery, cell,eod value, when V neg,eod When the value exceeds 0.6 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0122] Embodiment 16: The secondary battery according to embodiment 11, wherein the controller is programmed to, when the secondary battery is at a predetermined V at the end of the discharge cycle of the secondary battery, cell,eod When V neg,eod When the value exceeds 0.5 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0123] Embodiment 17: The method of any one of Embodiments 1 to 10 or the secondary battery of any one of Embodiments 11 to 16, wherein the carrier ions are lithium ions, sodium ions, potassium ions, magnesium ions, or aluminum ions.

[0124] Embodiment 18. The method of any one of Embodiments 1 to 10 or the secondary battery of any one of Embodiments 11 to 16, wherein the carrier ions are lithium ions, magnesium ions, or aluminum ions.

[0125] Embodiment 19: The method of any one of Embodiments 1 to 10 or the secondary battery of any one of Embodiments 11 to 16, wherein the carrier ions are lithium ions.

[0126] Embodiment 20: The method of any one of Embodiments 1 to 10 or the secondary battery of any one of Embodiments 11 to 16, wherein the carrier ions are magnesium ions.

[0127] Embodiment 21. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.2:1, respectively.

[0128] Embodiment 22. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.3:1, respectively.

[0129] Embodiment 23. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.5:1, respectively.

[0130] Embodiment 24: The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 2:1, respectively.

[0131] Embodiment 25: The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 3:1, respectively.

[0132] Embodiment 26: The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 4:1, respectively.

[0133] Embodiment 27: The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 5:1, respectively.

[0134] Embodiment 28. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.2:1, respectively.

[0135] Embodiment 29. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.3:1, respectively.

[0136] Embodiment 30. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.5:1, respectively.

[0137] Embodiment 31. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 2:1, respectively.

[0138] Embodiment 32. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 3:1, respectively.

[0139] Embodiment 33. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 4:1, respectively.

[0140] Embodiment 34: The method or secondary battery of any of the preceding embodiments, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 5:1, respectively.

[0141] Embodiment 35. A method or secondary battery according to any of the preceding embodiments, wherein the negative electrode comprises a microstructured silicon-containing active material, wherein the microstructured silicon-containing active material comprises a significant void volume fraction to accommodate volume expansion and contraction as carrier ions are incorporated into or leave the negative electrode during charge and discharge cycles.

[0142] Embodiment 36. The method or secondary battery of Embodiment 35, wherein the void volume fraction of the anode active material is at least 0.1.

[0143] Embodiment 37. The method or secondary battery of Embodiment 35 or 36, wherein the void volume fraction of the anode active material is no greater than 0.8.

[0144] Embodiment 38. The method or secondary battery of Embodiment 35 or 36, wherein the void volume fraction of the anode active material is from about 0.15 to about 0.75.

[0145] Embodiment 39: The method or secondary battery of Embodiment 35 or 36, wherein the void volume fraction of the anode active material is from about 0.2 to about 0.7.

[0146] Embodiment 40: The method or secondary battery of Embodiment 35 or 36, wherein the void volume fraction of the anode active material is from about 0.25 to about 0.6.

[0147] Embodiment 41. The method or secondary battery of Embodiment 35 or 36, wherein the microstructured anode active material comprises a macroporous, microporous or mesoporous material layer or a combination thereof.

[0148] Embodiment 42. A method for activating a secondary battery, the secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode permeated with an electrolyte containing carrier ions in ionic contact with the negative electrode and the positive electrode, and a V programmed with a predetermined discharge end voltage value. cell,eod A control unit, wherein the negative electrode comprises anode active silicon or an alloy thereof and has a coulombic capacity for the carrier ions, and the positive electrode comprises cathode active material and has a coulombic capacity for the carrier ions, the coulombic capacity of the negative electrode exceeds the coulombic capacity of the positive electrode, and the method comprises:

[0149] (i) transferring carrier ions from the positive electrode to the negative electrode to at least partially charge the secondary battery, wherein a solid electrolyte interface is formed on the surface of the negative electrode during the transfer, and

[0150] (ii) Transferring carrier ions from the auxiliary electrode to the positive electrode to generate a charge carrier when the cell is at a predetermined V cell,eod When the value is V, the secondary battery is provided with a positive electrode discharge end voltage V pos,eod and negative electrode discharge end voltage V neg,eod , where V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vs Li) but less than 0.9V (vs Li).

[0151] Embodiment 43. The method of embodiment 42, wherein step (ii) is performed after or simultaneously with step (i).

[0152] Embodiment 44. The method of Embodiment 43, wherein when step (ii) is performed after step (i), the method further comprises step (iii): after step (ii), transferring carrier ions from the positive electrode to the negative electrode to charge the secondary battery.

[0153] Example 45: The method of Example 43, 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 than the first rate.

[0154] Embodiment 46. The method of embodiment 42, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 95% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0155] Embodiment 47. The method of embodiment 42, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 96% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0156] Embodiment 48. The method of embodiment 42, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 97% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0157] Embodiment 49: The method of Embodiment 42, wherein when the primitive is at V cell,eod When V pos,eod The value of corresponds to the voltage at which the positive electrode is charged to at least 98% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0158] Embodiment 50. The method of embodiment 42, wherein when the primitive is at V cell,eod When V pos,eod The value of V corresponds to the voltage at which the positive electrode is charged to at least 99% of its Coulombic capacity, while V neg,eod At least 0.4V (vsLi) but less than 0.9V (vs Li).

[0159] Embodiment 51. The method of any one of Embodiments 42 to 50, wherein when the primitive is at V cell,eod When Vneg,eod At least 0.4V (vs Li) but less than 0.8V (vs Li).

[0160] Embodiment 52: The method of any one of Embodiments 42 to 50, wherein when the primitive is at V cell,eod When V neg,eod At least 0.5V (vs Li) but less than 0.8V (vs Li).

[0161] Embodiment 53. The method of any one of Embodiments 42 to 50, wherein when the primitive is at V cell,eod When V neg,eod At least 0.4V (vs Li) but less than 0.7V (vs Li).

[0162] Embodiment 54. The method of any one of Embodiments 42 to 50, wherein when the primitive is at V cell,eod When V neg,eod At least 0.5V (vs Li) but less than 0.7V (vs Li).

[0163] Embodiment 55. A secondary battery comprising a negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode and permeated with an electrolyte containing carrier ions in contact with the negative electrode and the positive electrode ions, an auxiliary electrode, and a control unit, wherein:

[0164] The positive electrode contains the cathode active material and has a coulombic capacity for carrier ions,

[0165] the negative electrode comprises anodically active silicon or an alloy thereof and has a coulombic capacity for carrier ions exceeding the coulombic capacity of the positive electrode,

[0166] The control unit includes a controller and a sensor electrically coupled to the sensor,

[0167] The sensor is configured to measure a cell voltage of the secondary battery and measure a voltage of the positive electrode or the negative electrode relative to the auxiliary electrode during operation of the secondary battery,

[0168] The controller is programmed with a predetermined cell charge end voltage V cell,eoc value and the predetermined cell discharge end voltage V cell,eod value, and

[0169] When the primitive is at a predetermined V cell,eod When the positive electrode has a discharge end voltage V pos,eod , and the negative electrode has a discharge end voltage V neg,eod , V pos,eod corresponds to a voltage at which the positive electrode voltage is charged to at least 95% of its Coulombic capacity, V neg,eodAt least 0.4V (vs Li) but less than 0.9V (vs Li).

[0170] Embodiment 56: The secondary battery according to Embodiment 55, wherein the controller is programmed to: when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value exceeds 0.9 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0171] Embodiment 57. The secondary battery according to embodiment 55, wherein the controller is programmed to: when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value exceeds 0.8 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0172] Embodiment 58. The secondary battery according to embodiment 55, wherein the controller is programmed to: when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value exceeds 0.7 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0173] Embodiment 59. The secondary battery according to embodiment 55, wherein the controller is programmed to: when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value exceeds 0.6 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0174] Embodiment 60. The secondary battery according to embodiment 55, wherein the controller is programmed to: when the secondary battery is at a predetermined V cell,eod value, when V neg,eod When the value exceeds 0.5 V (vs Li), carrier ions are transferred from the auxiliary electrode to the positive electrode or the negative electrode.

[0175] Embodiment 61. The method of any one of Embodiments 42-54 or the secondary battery of Embodiments 55-60, wherein the carrier ions are lithium ions, sodium ions, potassium ions, magnesium ions, or aluminum ions.

[0176] Embodiment 62. The method of any one of Embodiments 42 to 54 or the secondary battery of Embodiments 55 to 60, wherein the carrier ions are lithium ions, magnesium ions, or aluminum ions.

[0177] Embodiment 62. The method of any one of Embodiments 42 to 54 or the secondary battery of Embodiments 55 to 60, wherein the carrier ions are lithium ions.

[0178] Embodiment 63. The secondary battery of any of the methods of Embodiments 42 to 54 or Embodiments 55 to 60, wherein the carrier ions are magnesium ions.

[0179] Embodiment 64. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.2:1, respectively.

[0180] Embodiment 65. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.3:1, respectively.

[0181] Embodiment 66. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.5:1, respectively.

[0182] Embodiment 67. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 2:1, respectively.

[0183] Embodiment 68. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 3:1, respectively.

[0184] Embodiment 69. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 4:1, respectively.

[0185] Embodiment 70. The method or secondary battery of any preceding embodiment, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 5:1, respectively.

[0186] Embodiment 71. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.2:1, respectively.

[0187] Embodiment 72. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.3:1, respectively.

[0188] Embodiment 73. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 1.5:1, respectively.

[0189] Embodiment 74. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 2:1, respectively.

[0190] Embodiment 75. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 3:1, respectively.

[0191] Embodiment 76. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 4:1, respectively.

[0192] Embodiment 77. The method or secondary battery of any preceding embodiment, wherein the ratio of the coulombic capacity of the auxiliary electrode to the reversible coulombic capacity of the positive electrode when cycled relative to the counter electrode is at least 5:1, respectively.

[0193] Embodiment 78. A method or secondary battery according to any preceding embodiment, wherein the negative electrode comprises a microstructured silicon-containing active material comprising a significant void volume fraction to accommodate volume expansion and contraction as carrier ions are incorporated into or leave the negative electrode during charge and discharge cycles.

[0194] Embodiment 79. The method or secondary battery of Embodiment 78, wherein the void volume fraction of the anode active material is at least 0.1.

[0195] Embodiment 80. The method or secondary battery of Embodiment 78, wherein the void volume fraction of the anode active material is no greater than 0.8.

[0196] Embodiment 81: The method or secondary battery of Embodiment 78, wherein the void volume fraction of the anode active material is from about 0.15 to about 0.75.

[0197] Embodiment 82: The method or secondary battery of Embodiment 78, wherein the void volume fraction of the anode active material is from about 0.2 to about 0.7.

[0198] Embodiment 83. The method or secondary battery of Embodiment 78, wherein the void volume fraction of the anode active material is from about 0.25 to about 0.6.

[0199] Embodiment 84. The method or secondary battery of Embodiment 78, wherein the microstructured anode active material comprises a layer of macroporous, microporous or mesoporous material or a combination thereof.

[0200] As various changes could be made in the above articles, compositions and methods without departing from the scope of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A secondary battery comprising: A negative electrode, a positive electrode, a microporous separator between the negative electrode and the positive electrode, which is permeated with an electrolyte containing carrier ions that are in ionic contact with the negative electrode and the positive electrode, and a control unit, wherein: The positive electrode comprises a cathode 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 carrier ions that exceeds the coulombic capacity of the positive electrode, The control unit includes a controller and a sensor electrically coupled to the controller, The sensor is configured to measure a cell voltage of the secondary battery during operation of the secondary battery, The controller is programmed with a predetermined cell charge end voltage Vcell,eoc value and a predetermined cell discharge end voltage Vcell,eod value, and When the cell is at a predetermined Vcell,eod, the positive electrode has an end-of-discharge voltage Vpos,eod and the negative electrode has an end-of-discharge voltage Vneg,eod, the Vpos,eod value 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), Wherein an auxiliary electrode is used in the manufacturing process of the secondary battery, the sensor is further configured to measure the voltage of the positive electrode and the negative electrode equivalent to the auxiliary electrode, and the auxiliary electrode is removed from the secondary battery before packaging. 2 . The secondary battery according to claim 1 , wherein the carrier ions are lithium ions, sodium ions, potassium ions, magnesium ions or aluminum ions. 3 . The secondary battery according to claim 1 , wherein the carrier ions are lithium ions, magnesium ions or aluminum ions. The secondary battery according to claim 1 , wherein the carrier ions are lithium ions.

5. The secondary battery of claim 1, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to a counter electrode is at least 1.2:1, respectively.

6. The secondary battery of claim 1, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to a counter electrode is at least 1.5:1, respectively. 7 . The secondary battery of claim 1 , wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to a counter electrode is at least 2:1, respectively.

8. The secondary battery of claim 1, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to a counter electrode is at least 4:1, respectively.

9. The secondary battery of claim 1, wherein the ratio of the reversible coulombic capacity of the negative electrode to the reversible coulombic capacity of the positive electrode when cycled relative to a counter electrode is at least 5:1, respectively.

10. The secondary battery of claim 1, wherein the negative electrode comprises a microstructured silicon-containing active material comprising a significant void volume fraction to accommodate volume expansion and contraction as carrier ions are incorporated into or out of the negative electrode during charge and discharge cycles. 11 . The secondary battery according to claim 10 , wherein the void volume fraction of the microstructured silicon-containing active material is 0.2 to 0.

7. 12 . The secondary battery according to claim 10 , wherein the void volume fraction of the microstructured silicon-containing active material is 0.25 to 0.

6. 13 . The secondary battery according to claim 5 , wherein the carrier ions are lithium ions.

14. The secondary battery according to claim 6, wherein the carrier ions are lithium ions.

15. The secondary battery according to claim 7, wherein the carrier ions are lithium ions.

16. The secondary battery according to claim 8, wherein the carrier ions are lithium ions. 17 . The secondary battery according to claim 9 , wherein the carrier ions are lithium ions.

18. The secondary battery according to claim 10, wherein the carrier ions are lithium ions.

19. The secondary battery according to claim 11, wherein the carrier ions are lithium ions.

20. The secondary battery according to claim 12, wherein the carrier ions are lithium ions.

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