WO2019013536A1

WO2019013536A1 - Lithium secondary battery regeneration method

Info

Publication number: WO2019013536A1
Application number: PCT/KR2018/007825
Authority: WO
Inventors: 홍철기; 이재헌; 김석구; 김동규; 김대수
Original assignee: 주식회사 엘지화학
Priority date: 2017-07-10
Filing date: 2018-07-10
Publication date: 2019-01-17

Abstract

A lithium secondary battery regeneration method according to the present invention is a method for regenerating a secondary battery comprising: an electrode assembly in which electrodes including a positive electrode and a negative electrode and a separator are alternately stacked together; and a battery case for receiving the electrode assembly. The method comprises: a lithium resupply step of further providing the secondary battery with a lithium resupply electrode, and setting the positive electrode as a counter electrode and setting the lithium resupply electrode as a working electrode to supply lithium ions to the positive electrode through the lithium resupply electrode; and a negative electrode discharge step of, after resupplying lithium ions to the positive electrode through the resupply step, setting the lithium resupply electrode as a counter electrode and setting the negative electrode as a working electrode to fully discharge the negative electrode up to a discharge limit.

Description

Regeneration method of lithium secondary battery

Mutual citation with related application

This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0087274, filed on Jul. 10, 2017, and Korean Patent Application No. 10-2018-0079493, filed on Jul. 09, 2018, The entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to a method for regenerating a lithium secondary battery.

Unlike primary batteries, rechargeable secondary batteries can be recharged, and they are being researched and developed recently due to their small size and high capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing.

The secondary battery is classified into a coin type battery, a cylindrical type battery, a square type battery, and a pouch type battery depending on the shape of the battery case. An electrode assembly mounted in a battery case of a secondary battery is a chargeable and dischargeable power generation device having a stacked structure of an electrode and a separation membrane.

The electrode assembly includes a jelly-roll type in which a separator is interposed between a positive electrode and a negative electrode coated with an active material, and a stacked type in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator interposed therebetween And a stack / folding type in which stacked unit cells are wound with a long length separating film.

On the other hand, as the conventional lithium secondary battery is repeatedly used, lithium ions are gradually transferred from the anode to the cathode and charged, and lithium ions are gradually transferred from the cathode to the anode and discharged repeatedly while the lithium source is gradually lacking. The battery capacity was reduced and degraded. Currently, methods for recycling and reusing such degenerated lithium secondary batteries are being studied.

One aspect of the present invention is to provide a method for regenerating a lithium secondary battery capable of improving lifetime characteristics of the lithium secondary battery.

Another aspect of the present invention is to provide a regeneration method of a lithium secondary battery capable of recovering a battery capacity by reapplying lithium ions to an anode through a lithium re-supply electrode without disassembling the secondary battery.

Another aspect of the present invention is to provide a regenerating method of a lithium secondary battery capable of increasing the recovery of the battery capacity by completely discharging the negative electrode to the discharge limit through the lithium re-supply electrode without disassembling the secondary battery.

Another aspect of the present invention is to provide a regeneration method of a lithium secondary battery capable of adjusting a balance between an anode and a cathode

A method of regenerating a lithium secondary battery according to an exemplary embodiment of the present invention is a method of regenerating a rechargeable lithium battery including an electrode assembly including an electrode assembly including an anode and a cathode and a separator alternately stacked, Wherein the lithium secondary battery further comprises a lithium re-supply electrode, wherein the anode is set as an opposite electrode, the lithium re-supply electrode is set as a working electrode, and the lithium re- Supplying a lithium material to the anode as lithium ions and supplying the lithium material to the anode through the re-supply step, and then setting the lithium material supplying electrode as a counter electrode, setting the cathode as a working electrode, And a cathode discharge step of completely discharging the cathode to the discharge limit, whereby the capacity of the secondary battery can be restored.

According to the present invention, the secondary battery further includes a lithium re-supply electrode, and the battery capacity can be restored by re-supplying lithium ions to the anode through the lithium re-supply electrode without disassembling the secondary battery.

In addition, according to the present invention, it is possible to increase the recovery of the battery capacity by completely discharging the negative electrode to the discharge limit through the lithium re-supply electrode without disassembling the secondary battery. That is, lithium ions are moved from the cathode to the anode, and lithium ions are left in the cathode at the time of discharging, so that a complete discharge is not achieved. However, when lithium is supplied as a counter electrode and a cathode is set as a working electrode, It is possible to completely discharge the negative electrode to the discharge limit while moving the lithium ion to the electrode.

According to the present invention, by regulating the balance between the anode and the cathode by regulating the amount of re-supply of lithium ions and the amount of discharge of the cathode to the anode through the lithium re-supply electrode, the electrode capacity can be remarkably restored.

1 is a perspective view of a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention.

2 is a front view showing a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention.

3 is an exploded perspective view illustrating an electrode assembly and a lithium re-supply electrode in a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention.

4 is a front perspective view exemplarily showing a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention.

FIG. 5 is a bottom perspective view illustrating a lithium secondary battery according to an embodiment of the present invention, which is applied to a method of regenerating a lithium secondary battery. FIG.

FIG. 6 is a graph illustrating differential voltage data used in a determination step in a method of regenerating a lithium secondary battery according to an embodiment of the present invention. Referring to FIG.

FIG. 7 is a graph illustrating a change in resistance of a lithium secondary battery regenerated by a method of regenerating a lithium secondary battery according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Furthermore, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In the following description of the present invention, a detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

FIG. 1 is a perspective view of a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a lithium secondary battery according to an embodiment of the present invention. FIG. 3 is an exploded perspective view illustrating an electrode assembly and a lithium re-supply electrode in a lithium secondary battery applied to a method of regenerating a lithium secondary battery according to an embodiment of the present invention. FIG.

1 to 3, a method of regenerating a lithium secondary battery according to an embodiment of the present invention includes a step of supplying a lithium material to an anode 121 through a lithium material supplying electrode 130, And a cathode discharge step of completely discharging the cathode 122 to the discharge limit via the supply electrode 130 to restore the capacity of the secondary battery 100. The regenerating method of the lithium secondary battery according to an embodiment of the present invention may further include a discharging step of discharging the electrode 123 before the supplying of the lithium material and a discharging step of discriminating the degree of degradation of the anode 121 and the cathode 122 And a balance re-establishment step of re-establishing the balance of the electrode 123. [0033]

FIG. 4 is a front perspective view illustrating a lithium secondary battery according to an embodiment of the present invention. FIG. 5 is a cross-sectional view of a lithium rechargeable battery according to an embodiment of the present invention. 1 is a bottom perspective view exemplarily showing a lithium secondary battery.

Hereinafter, a method of regenerating a lithium secondary battery according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG.

3 and 4, a secondary battery 100 applied to a method for regenerating a lithium secondary battery according to an embodiment of the present invention includes a battery case 100 having an electrode assembly 120 and an accommodating portion for accommodating the electrode assembly 120 110). The secondary battery 100 applied to the regenerating method of the lithium secondary battery according to an embodiment of the present invention may further include an electrolyte and a lithium re-supply electrode 130 to be received in the battery case 110.

The electrode assembly 120 is a chargeable and dischargeable power generation element, and the electrode 123 and the separation membrane 124 are assembled to form a structure in which the layers are alternately stacked. In addition, the electrode assembly 120 may include electrode leads 125 and 126 that are electrically connected to the electrode 123. The electrode assembly 120 may further include

electrode tabs

127 and 128 protruding from the side surface of the electrode 123 and electrically connected to the electrode leads 125 and 126.

The electrode 123 may be composed of a positive electrode 121 and a negative electrode 122. At this time, the electrode assembly 120 may have a structure in which the anode 121 / the separation membrane 124 / the cathode 122 are alternately stacked.

The anode 121 includes a cathode current collector (not shown) and a cathode active material (not shown) coated on the cathode current collector. The cathode 122 includes a cathode current collector (not shown) and a cathode active material (Not shown).

The positive electrode collector may be made of, for example, a foil made of aluminum (Al).

The cathode active material may be composed of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture thereof containing at least one of the foregoing.

In addition, the cathode active material may be made of a Hi Ni-based cathode material as another example. Here, the Hi Ni-based cathode material may include any one or more of LiNiMnCoO-based, LiNiCoAl-based, and LiMiMnCoAl-based materials.

The anode current collector may be made of, for example, a foil made of copper (Cu) or nickel (Ni).

The negative electrode active material may be made of a material including artificial graphite.

In addition, the negative electrode active material may be made of lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or an alloy thereof.

The separator 124 is made of an insulating material and electrically insulates between the anode 121 and the cathode 122. Here, the separation membrane 124 may be located between the anode 121 and the cathode 122, and on the outer surface of the anode 121 and the cathode 122. At this time, the outermost side of the separation membrane 134 may be provided so as to surround the electrode assembly 120 so as to be positioned between the lithium re-supply electrode 130 and the anode 121 and the cathode 122.

In addition, the separation membrane 124 may be formed of a polyolefin-based resin film such as polyethylene or polypropylene having micropores, for example.

The electrode leads 125 and 126 may include a positive electrode lead 125 electrically connected to the positive electrode 121 and a negative electrode lead 126 electrically connected to the negative electrode 122.

The

electrode tabs

127 and 128 protrude from the side surface of the anode 121 and protrude from the side surfaces of the cathode 122 and the anode tab 127 connecting the anode 121 to the anode lead 125, And an anode tab 126 electrically connected to the anode 126.

The electrolytic solution may be, for example, a lithium-containing non-aqueous electrolytic solution comprising a non-aqueous electrolyte and a lithium salt.

Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylenecarbonate, dimethyl carbonate, diethyl carbonate, But are not limited to, butylolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, But are not limited to, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxy methane, dioxolane derivatives, sulfolane, methyl sulfolane, Derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, ethyl propionate and the like can be used.

At this time, the lithium salt is a material that is readily soluble in non-aqueous liquid electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB10Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, lithium tetraphenylborate, imide and the like can be used.

Referring to FIGS. 3 to 5, a plurality of lithium re-supply electrodes 130 may be accommodated in the battery case 110. The lithium re-supply electrode 130 includes a first lithium re-supply electrode 131 located at one side of the electrode assembly 120 and a second lithium material supply electrode 132 located at the other side of the electrode assembly 120 . At this time, the electrode assembly 120 is positioned in the receiving portion of the battery case 110, and the first lithium re-supply electrode 131 and the two lithium re-supply electrodes 132 ) Can be located.

Further, lithium re-supply electrode leads 133 and 134 electrically connected to the lithium re-supply electrode 130 may be further provided.

In addition, the lithium re-supply electrode 130 may be made of, for example, lithium metal.

The plurality of lithium re-supply electrodes 130 may surround the opposite ends of the electrode assembly 120, respectively. At this time, the lithium re-supply electrode 130 may be formed in, for example, a " C " shape. Here, the through hole 131a through which the electrode tab is passed may be formed in the lithium re-supply electrode 130. [

Meanwhile, lithium

re-supply electrode tabs

135 and 136 protruded from the side surface of the lithium re-supply electrode 130 may be further provided. Here, the lithium

re-supply electrode tabs

135 and 136 may be electrically connected to the lithium re-supply electrode leads 133 and 134. At this time, for example, the lithium

re-supply electrode tabs

135 and 136 may be made of lithium metal, and the lithium re-supply electrode leads 133 and 134 may be made of aluminum.

The lithium

re-supply electrode tabs

135 and 136 and the lithium re-supply electrode leads 133 and 134 can be mutually fixed through welding.

The lithium re-supply electrode 130 and the lithium

re-supply electrode tabs

135 and 136 are accommodated in the battery case 110 and one side of the lithium re-supply electrode leads 133 and 134 is positioned inside the battery case 110 And the other side portion may protrude to the outside of the battery case 110.

The discharging step may discharge the electrode 123 before the lithium refeeding step. Here, the discharging step discharges the lithium ions of the cathode 122 to the anode 121 as much as possible. That is, the lithium ions in the cathode 122 can be moved to the anode 121 as much as possible.

The lithium re-supply step further includes a lithium re-supply electrode 130 in the secondary battery 100. The anode 121 is set as a counter electrode and the lithium re-supply electrode 130 is connected to a working electrode electrode, and lithium ions are charged into the anode 121 through the lithium re-supply electrode 130. Here, the working electrode is an electrode for supplying lithium ions and the counter electrode is an electrode for receiving lithium ions.

Here, the lithium refeeding step electrically turns off between the anode 121 and the cathode 122, and electrically turns on the lithium re-supply electrode 130 and the cathode 122. That is, when the lithium secondary battery 100 is used in an electronic device or the like, the lithium re-supply electrode 130 is electrically turned off and the anode 121 and the cathode 122 are electrically turned on , The lithium re-supply electrode 130 and the cathode 122 are electrically turned on and the anode 121 is turned off when the capacity of the lithium secondary battery 100 is restored. At this time, the electrical connection between the positive electrode lead 125 connected to the positive electrode 121, the negative electrode lead 126 connected to the negative electrode 122 and the lithium material supplying electrode leads 133 and 134 connected to the lithium material supplying electrode 130, The anode 121, the cathode 122, and the lithium re-supply electrode 130 can be selectively turned on / off by turning on / off the lithium re-supply electrode 130.

In the lithium re-supply step, for example, one of the plurality of lithium re-supply electrodes 130 is set as a working electrode to charge lithium ions into the positive electrode 121, When the charged amount of the lithium re-supply electrode 121 is 40 to 60%, the other lithium re-supply electrode 130 may be set as a working electrode in place of any one of the lithium re- have.

Here, in the lithium refeeding step, for example, a first lithium re-supply electrode 131 positioned at one side of the electrode assembly 120 is set as a working electrode, lithium ions are charged into the anode 121, When the charged amount of the anode 121 reaches 50%, the second lithium re-supply electrode 132 may be set as a working electrode instead of the first lithium re-supply electrode 131 to fully charge the lithium ion into the anode 121.

Accordingly, lithium ions in the positive electrode 121 are supplied using both the first lithium re-supply electrode 131 and the second lithium re-supply electrode 132 located on both sides of the electrode assembly 120, ) Of lithium ions. That is, when a lithium source is supplied only to one side of the anode 121, a lithium source is supplied to one side. However, when a lithium source is supplied to both sides of the anode 121, a lithium source can be supplied more uniformly.

In the cathode discharge step, the lithium re-supply electrode 130 is set as the counter electrode, the cathode electrode 122 is set as the working electrode, and the cathode 122 to the discharge limit. That is, the lithium ions remaining on the cathode 122 are moved to the lithium re-supply electrode 130. Therefore, due to the capacity limitation of the anode 121, the lithium ions can not be moved to the anode 121 from the cathode 122 and the remaining lithium ions can be moved to the lithium re-supply electrode 130. As a result, the lithium ions remaining in the cathode 122 can be removed and new lithium ions can be supplied.

At this time, it is possible to increase the electrode capacity and supply new lithium by repeating the lithium refeeding step and the cathode discharging step.

In the cathode discharge step, one of the plurality of lithium re-supply electrodes 130 is set as a counter electrode to discharge the cathode 122, and the discharge amount of the cathode 122 is set to 40 ~ 60%, it is possible to completely discharge the cathode 122 by setting one lithium re-supply electrode 130 as a counter electrode in place of any one of the lithium re-supply electrodes 130.

Here, in the cathode discharge step, for example, the first lithium re-supply electrode 131 positioned at one side of the electrode assembly 120 is set as the counter electrode, and the first lithium re- When the discharge amount of the cathode 122 becomes 50%, the second lithium re-supply electrode 132 is set as the counter electrode instead of the first lithium re-supply electrode 131, and the negative electrode 122 ), The lithium ion can be completely discharged.

In the method of regenerating a lithium secondary battery according to an embodiment of the present invention, the negative electrode discharge step further includes a pulse applying step of applying a high current pulse to the negative electrode 122 to remove the inorganic salt layer and the organic salt layer stacked on the negative electrode 122 can do.

More specifically, as the secondary battery 100 is repeatedly used, the cathodic discharge step is carried out so that the inorganic salt layer and the organic salt layer are applied to the cathode 122 by applying a strong current pulse stronger to the cathode 122, The cathode 122 can be detached from the anode 122 by increasing the current.

That is, inorganic salts and organic salts, which are lithium salts contained in the electrolytic solution, are laminated on the outer surface of the cathode 122 to form a layer, and the inorganic salt layer and the organic salt, which are formed on the outer surface of the cathode 122, when the organic salt layer prevents the movement of lithium ions located in the negative electrode active material in the negative electrode 122, if a strong current pulse is applied to the negative electrode 122 to increase the moving speed of the lithium ion, the inorganic salt layer and the organic salt layer can be pushed out by the lithium ion to separate the inorganic salt layer and the organic salt layer from the cathode 122. [

Here, since the pulse size of the current is proportional to the moving speed of the lithium ion, the moving speed of the lithium ion is increased as the pulse size of the current is stronger, and the stronger high current pulse is applied to the inorganic salt layer and organic salt layer can be removed.

In addition, the pulse applying step can specifically apply a current pulse of, for example, 1.0 to 2.5 C to the cathode 122. Here, when a current pulse lower than 1.0 C is applied to the cathode 122, the movement speed of the lithium ion is lowered and the effect of removing the inorganic salt layer and the organic salt layer may be small.

If a current pulse higher than 2.5 C is applied to the cathode 122, the anode active material may be damaged or destroyed due to excessive high currents. In addition, when a current pulse higher than 2.5 C is applied to the cathode 122, the SEI (solid electrolyte interface) layer formed on the surface of the cathode 122 is broken due to excessive high current, and lithium ions become dead lithium, The dendrite may grow to increase the resistance and the continuous dendrite may damage the separation membrane 124 and may short-circuit the anode 121 and the cathode 122, have.

At this time, more specifically, for example, a current pulse of 2.5 C (if the battery capacity is 50 Ah and a current of 2.5 C is applied, a current of 50 * 2.5 = 125 A flows) can be applied to the cathode 122 .

The pulse applying step is included in the cathode discharging step to set any one of the plurality of lithium re-supply electrodes 130 as the counter electrode, and when the cathode 122 is discharged, When the discharge amount of the cathode 122 is 40 to 60%, the other lithium re-supply electrode 130 is set as the counter electrode instead of the one of the lithium re-supply electrodes 130, and the pulse applying step is performed And the cathode 122 can be completely discharged. Accordingly, it is possible to prevent a problem that the anode structure is collapsed due to damage or destruction of the cathode active material, which is moved to the anode 121 by the lithium ions moved in a strong current in the pulse applying step.

In the determining step, the lithium re-supply electrode 130 is set as a working electrode, the anode 121 and the cathode 122 are set as counter electrodes, and the anode 121 and the cathode 122, It is possible to detect the degree of degradation of the anode 121 and the cathode 122 by detecting the voltage value and the charging capacity of the anode 122 and the cathode 122, respectively.

When the voltage value and the charging capacity are measured through the anode 121 and the cathode 122, the voltage value and the charging capacity for each of the anode 121 and the cathode 122 can not be measured. The positive electrode 121 and the negative electrode 122 are formed by one electrical connection, so that only one voltage value and the charging capacity are shown.

However, if the lithium re-supply electrode 130 is set as the reference electrode, the lithium re-supply electrode 130 and the anode 121 may be connected, and the lithium re-supply electrode 130 and the cathode 122 may be individually connected , The anode voltage (121), and the cathode voltage (122) and the charging capacity can be separately measured. As a result, the degree of degradation of the anode 121 and the cathode 122 can be individually and accurately discriminated through the lithium re-supply electrode 130.

In the graph of Fig. 6, the X axis represents the charging capacity (Capacity), and the Y axis represents the differential voltage (dQ / dQ). Here, the differential voltage of the Y-axis represents a value obtained by differentiating the voltage of the cathode by a differential value (dV) divided by a value (dQ) obtained by differentiating the charging capacity of the cathode. The graph of FIG. 6 can be divided into A, B, C, and D zones according to the charging capacity.

The zones B and C shown in FIG. 6 are shifted to the right on the graph of FIG. 6 when the active material degrades, and the zone D is shifted to the right when lithium available in the lithium secondary battery is reduced.

Accordingly, the degradation tendency of the secondary battery can be accurately determined by checking the degeneration degree of the active material and the amount of available lithium through the graph shown in FIG.

Meanwhile, a cathode differential voltage graph such as the cathode differential voltage graph shown in FIG. 6 can also be shown. As a result, the data of the cathode and the anode can be separately measured, and the degradation degree of the anode and the cathode can be individually discriminated.

In particular, it is possible to monitor the differential voltage graph of the anode and the cathode in real time to supply lithium at the required time.

3 to 5, in the balancing step, the degree of deterioration of the anode 121 and the cathode 122 is discriminated through the discrimination step, and the amount of lithium supplied to the anode 121 through the lithium refeeding step, The balance of the electrode 123 can be reestablished by adjusting the discharge amount of the cathode 122 through the step.

More specifically, if it is determined that the degradation degree of the anode 121 is further advanced by the discrimination step than the cathode 122, the amount of lithium supplied through the lithium refeeding step is increased to change the capacity of the anode 121 and the cathode 122 Direction.

On the other hand, if it is determined that the degradation degree of the cathode 122 is further advanced through the discrimination step than the anode 121, the amount of lithium discharge is increased through the cathode discharge step to increase the capacity of the anode 121 and the cathode 122 in the corresponding direction .

That is, when lithium ions move between the anode 121 and the cathode 122, the capacity of any one of the anode 121 and the cathode 122 is restricted when charging and discharging are performed, It is possible to solve the problem that the capacity of the electrode 123 of the plasma display panel is limited. As a result, the capacity of the secondary battery 100 can be increased more effectively.

The graph shown in FIG. 7 shows the resistance change of the lithium secondary battery A regenerated by the regeneration method of the lithium secondary battery according to the embodiment of the present invention and the lithium secondary battery B before regeneration. Here, the horizontal axis of the graph represents SOC (State of Charge) and the vertical axis represents resistance. In the graph of FIG. 6, 1.5 C (Coulomb) of electricity was applied to the lithium secondary battery to detect a resistance value when a current of 98.7 A flows through the lithium secondary battery. At this time, the electricity was cut for 10 seconds for each section of the charged state, and the resistance value was detected for each section.

7, it can be seen that the resistance of the lithium secondary battery A regenerated by the regenerating method of the lithium secondary battery according to the embodiment of the present invention is lower than the resistance of the lithium secondary battery B before regeneration . As a result, it can be seen that the performance of the lithium secondary battery A regenerated by the regenerating method of the lithium secondary battery according to the embodiment of the present invention is improved

Hereinafter, a method for regenerating a lithium secondary battery according to another embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

1 to 5, the method for regenerating the lithium secondary battery according to another embodiment of the present invention differs from the method for determining the determination step in comparison with the method for regenerating the lithium secondary battery according to the above embodiment . Therefore, the present embodiment will briefly describe the contents overlapping one embodiment, and focus on the differences.

A method of determining a method of regenerating a lithium secondary battery according to another embodiment of the present invention includes applying a constant current pulse to the anode 121 and the cathode 122 for a predetermined time based on the lithium re- The resistance value of each of the positive electrode 121 and the negative electrode 122 is detected through the value of the value and the amount of change of the voltage and if the resistance value is larger, The degree of degeneration can be determined.

In this case, for example, if a 1C current pulse is applied to the anode 121 and the cathode 122 (if a battery capacity is 50 Ah and a 1C current pulse is applied, a current of 50 * 1 = 50 A flows) The resistance value of each of the anode 121 and the cathode 122 can be detected through the value of the current and the amount of change of the voltage.

Meanwhile, according to the regenerating method of a lithium secondary battery according to another embodiment of the present invention, depending on the degradation degree of the anode 121 and the cathode 122 determined through the discriminating step in the balance refining step, The balance between the anode 121 and the cathode 122 can be regulated by adjusting the amount of lithium supplied to the anode 121 and the amount of discharge of the cathode 122 through the cathode discharging step.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Further, the scope of protection of the invention will be clarified by the appended claims.

Claims

A method for regenerating a secondary battery, the method comprising the steps of: preparing a battery case having an electrode assembly including a positive electrode and a negative electrode,

The secondary battery further includes a lithium rechargeable electrode, wherein the positive electrode is set as an opposite electrode, the lithium material supplying electrode is set as a working electrode, lithium ions are supplied to the positive electrode through the lithium material supplying electrode, A lithium refeeding step of charging; And

Supplying the lithium re-supply electrode to the counter electrode through the lithium refeeding step, setting the lithium re-supply electrode as a counter electrode, setting the cathode as a working electrode, and discharging the negative electrode to a discharge limit, Comprising the steps of:

And regenerating the capacity of the secondary battery.
The method according to claim 1,

Before the lithium refeeding step,

And discharging the electrode by discharging lithium ions from the negative electrode to the positive electrode.
The method according to claim 1,

The regenerating method of the lithium secondary battery repeatedly performing the lithium refeeding step and the cathodic discharging step to recover the capacity of the secondary battery.
The method according to claim 1,

The lithium refeeding step

One of the plurality of lithium re-supply electrodes is set as a working electrode, and lithium ions are charged into the positive electrode,

Wherein when the charged amount of the positive electrode is 40 to 60%, the other one of the lithium re-supply electrodes is set as a working electrode instead of the one of the lithium re-supply electrodes, thereby fully charging the lithium ion into the positive electrode.
The method according to claim 1,

The cathode discharge step

One of the lithium re-supply electrodes provided as a plurality of lithium re-supply electrodes is set as a counter electrode to discharge the negative electrode,

Wherein when the discharge amount of the negative electrode is 40 to 60%, the other one of the lithium re-supply electrodes is set as a counter electrode instead of the one of the lithium re-supply electrodes, thereby completely discharging the negative electrode.
The method according to claim 4 or 5,

Wherein the plurality of lithium re-supply electrodes comprise a first lithium re-supply electrode located at one side of the electrode assembly and a second lithium re-supply electrode located at the other side of the electrode assembly.
The method according to claim 4 or 5,

The cathode discharge step

Applying a high current pulse to the negative electrode to remove an inorganic salt layer and an organic salt layer stacked on the negative electrode.
The method of claim 7,

Wherein the pulse applying step applies a current pulse of 1.0 to 2.5 C to the negative electrode.
The method according to any one of claims 1 to 5,

Further comprising a discriminating step of discriminating a degeneration degree of the anode and the cathode,

Wherein the step of regenerating the lithium secondary battery further comprises the step of supplying the lithium material or the step of discharging the cathode only when the degradation degree of the positive electrode and the negative electrode determined through the determining step is a certain range or more.
The method of claim 9,

Determining a degradation degree of the anode and the cathode through the determination step,

And regulating the balance of the electrode by regulating the amount of lithium supplied to the positive electrode through the lithium supplying step and the discharging amount of the negative electrode through the negative discharging step.
The method of claim 9,

The determining step

The positive electrode and the negative electrode are set as opposing electrodes and the voltage value and the charging capacity of the positive electrode and the negative electrode with reference to the lithium material supplying electrode are detected, And regenerating the lithium secondary battery.
The method of claim 9,

The determining step

A resistance value of each of the positive electrode and the negative electrode is detected by applying a constant current pulse to the positive electrode and the negative electrode for a predetermined time with reference to the lithium re-supply electrode, The deterioration degree of the positive electrode and the negative electrode is determined in such a manner that it is determined that the deterioration is greater.
The method according to any one of claims 1 to 5,

Wherein the lithium re-supply electrode is made of lithium metal.